//===--- SemaOverload.cpp - C++ Overloading -------------------------------===// // // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. // See https://llvm.org/LICENSE.txt for license information. // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception // //===----------------------------------------------------------------------===// // // This file provides Sema routines for C++ overloading. // //===----------------------------------------------------------------------===// #include "clang/AST/ASTContext.h" #include "clang/AST/CXXInheritance.h" #include "clang/AST/DeclObjC.h" #include "clang/AST/DependenceFlags.h" #include "clang/AST/Expr.h" #include "clang/AST/ExprCXX.h" #include "clang/AST/ExprObjC.h" #include "clang/AST/TypeOrdering.h" #include "clang/Basic/Diagnostic.h" #include "clang/Basic/DiagnosticOptions.h" #include "clang/Basic/PartialDiagnostic.h" #include "clang/Basic/SourceManager.h" #include "clang/Basic/TargetInfo.h" #include "clang/Sema/Initialization.h" #include "clang/Sema/Lookup.h" #include "clang/Sema/Overload.h" #include "clang/Sema/SemaInternal.h" #include "clang/Sema/Template.h" #include "clang/Sema/TemplateDeduction.h" #include "llvm/ADT/DenseSet.h" #include "llvm/ADT/Optional.h" #include "llvm/ADT/STLExtras.h" #include "llvm/ADT/SmallPtrSet.h" #include "llvm/ADT/SmallString.h" #include #include using namespace clang; using namespace sema; using AllowedExplicit = Sema::AllowedExplicit; static bool functionHasPassObjectSizeParams(const FunctionDecl *FD) { return llvm::any_of(FD->parameters(), [](const ParmVarDecl *P) { return P->hasAttr(); }); } /// A convenience routine for creating a decayed reference to a function. static ExprResult CreateFunctionRefExpr(Sema &S, FunctionDecl *Fn, NamedDecl *FoundDecl, const Expr *Base, bool HadMultipleCandidates, SourceLocation Loc = SourceLocation(), const DeclarationNameLoc &LocInfo = DeclarationNameLoc()){ if (S.DiagnoseUseOfDecl(FoundDecl, Loc)) return ExprError(); // If FoundDecl is different from Fn (such as if one is a template // and the other a specialization), make sure DiagnoseUseOfDecl is // called on both. // FIXME: This would be more comprehensively addressed by modifying // DiagnoseUseOfDecl to accept both the FoundDecl and the decl // being used. if (FoundDecl != Fn && S.DiagnoseUseOfDecl(Fn, Loc)) return ExprError(); DeclRefExpr *DRE = new (S.Context) DeclRefExpr(S.Context, Fn, false, Fn->getType(), VK_LValue, Loc, LocInfo); if (HadMultipleCandidates) DRE->setHadMultipleCandidates(true); S.MarkDeclRefReferenced(DRE, Base); if (auto *FPT = DRE->getType()->getAs()) { if (isUnresolvedExceptionSpec(FPT->getExceptionSpecType())) { S.ResolveExceptionSpec(Loc, FPT); DRE->setType(Fn->getType()); } } return S.ImpCastExprToType(DRE, S.Context.getPointerType(DRE->getType()), CK_FunctionToPointerDecay); } static bool IsStandardConversion(Sema &S, Expr* From, QualType ToType, bool InOverloadResolution, StandardConversionSequence &SCS, bool CStyle, bool AllowObjCWritebackConversion); static bool IsTransparentUnionStandardConversion(Sema &S, Expr* From, QualType &ToType, bool InOverloadResolution, StandardConversionSequence &SCS, bool CStyle); static OverloadingResult IsUserDefinedConversion(Sema &S, Expr *From, QualType ToType, UserDefinedConversionSequence& User, OverloadCandidateSet& Conversions, AllowedExplicit AllowExplicit, bool AllowObjCConversionOnExplicit); static ImplicitConversionSequence::CompareKind CompareStandardConversionSequences(Sema &S, SourceLocation Loc, const StandardConversionSequence& SCS1, const StandardConversionSequence& SCS2); static ImplicitConversionSequence::CompareKind CompareQualificationConversions(Sema &S, const StandardConversionSequence& SCS1, const StandardConversionSequence& SCS2); static ImplicitConversionSequence::CompareKind CompareDerivedToBaseConversions(Sema &S, SourceLocation Loc, const StandardConversionSequence& SCS1, const StandardConversionSequence& SCS2); /// GetConversionRank - Retrieve the implicit conversion rank /// corresponding to the given implicit conversion kind. ImplicitConversionRank clang::GetConversionRank(ImplicitConversionKind Kind) { static const ImplicitConversionRank Rank[(int)ICK_Num_Conversion_Kinds] = { ICR_Exact_Match, ICR_Exact_Match, ICR_Exact_Match, ICR_Exact_Match, ICR_Exact_Match, ICR_Exact_Match, ICR_Promotion, ICR_Promotion, ICR_Promotion, ICR_Conversion, ICR_Conversion, ICR_Conversion, ICR_Conversion, ICR_Conversion, ICR_Conversion, ICR_Conversion, ICR_Conversion, ICR_Conversion, ICR_Conversion, ICR_Conversion, ICR_OCL_Scalar_Widening, ICR_Complex_Real_Conversion, ICR_Conversion, ICR_Conversion, ICR_Writeback_Conversion, ICR_Exact_Match, // NOTE(gbiv): This may not be completely right -- // it was omitted by the patch that added // ICK_Zero_Event_Conversion ICR_C_Conversion, ICR_C_Conversion_Extension }; return Rank[(int)Kind]; } /// GetImplicitConversionName - Return the name of this kind of /// implicit conversion. static const char* GetImplicitConversionName(ImplicitConversionKind Kind) { static const char* const Name[(int)ICK_Num_Conversion_Kinds] = { "No conversion", "Lvalue-to-rvalue", "Array-to-pointer", "Function-to-pointer", "Function pointer conversion", "Qualification", "Integral promotion", "Floating point promotion", "Complex promotion", "Integral conversion", "Floating conversion", "Complex conversion", "Floating-integral conversion", "Pointer conversion", "Pointer-to-member conversion", "Boolean conversion", "Compatible-types conversion", "Derived-to-base conversion", "Vector conversion", "SVE Vector conversion", "Vector splat", "Complex-real conversion", "Block Pointer conversion", "Transparent Union Conversion", "Writeback conversion", "OpenCL Zero Event Conversion", "C specific type conversion", "Incompatible pointer conversion" }; return Name[Kind]; } /// StandardConversionSequence - Set the standard conversion /// sequence to the identity conversion. void StandardConversionSequence::setAsIdentityConversion() { First = ICK_Identity; Second = ICK_Identity; Third = ICK_Identity; DeprecatedStringLiteralToCharPtr = false; QualificationIncludesObjCLifetime = false; ReferenceBinding = false; DirectBinding = false; IsLvalueReference = true; BindsToFunctionLvalue = false; BindsToRvalue = false; BindsImplicitObjectArgumentWithoutRefQualifier = false; ObjCLifetimeConversionBinding = false; CopyConstructor = nullptr; } /// getRank - Retrieve the rank of this standard conversion sequence /// (C++ 13.3.3.1.1p3). The rank is the largest rank of each of the /// implicit conversions. ImplicitConversionRank StandardConversionSequence::getRank() const { ImplicitConversionRank Rank = ICR_Exact_Match; if (GetConversionRank(First) > Rank) Rank = GetConversionRank(First); if (GetConversionRank(Second) > Rank) Rank = GetConversionRank(Second); if (GetConversionRank(Third) > Rank) Rank = GetConversionRank(Third); return Rank; } /// isPointerConversionToBool - Determines whether this conversion is /// a conversion of a pointer or pointer-to-member to bool. This is /// used as part of the ranking of standard conversion sequences /// (C++ 13.3.3.2p4). bool StandardConversionSequence::isPointerConversionToBool() const { // Note that FromType has not necessarily been transformed by the // array-to-pointer or function-to-pointer implicit conversions, so // check for their presence as well as checking whether FromType is // a pointer. if (getToType(1)->isBooleanType() && (getFromType()->isPointerType() || getFromType()->isMemberPointerType() || getFromType()->isObjCObjectPointerType() || getFromType()->isBlockPointerType() || First == ICK_Array_To_Pointer || First == ICK_Function_To_Pointer)) return true; return false; } /// isPointerConversionToVoidPointer - Determines whether this /// conversion is a conversion of a pointer to a void pointer. This is /// used as part of the ranking of standard conversion sequences (C++ /// 13.3.3.2p4). bool StandardConversionSequence:: isPointerConversionToVoidPointer(ASTContext& Context) const { QualType FromType = getFromType(); QualType ToType = getToType(1); // Note that FromType has not necessarily been transformed by the // array-to-pointer implicit conversion, so check for its presence // and redo the conversion to get a pointer. if (First == ICK_Array_To_Pointer) FromType = Context.getArrayDecayedType(FromType); if (Second == ICK_Pointer_Conversion && FromType->isAnyPointerType()) if (const PointerType* ToPtrType = ToType->getAs()) return ToPtrType->getPointeeType()->isVoidType(); return false; } /// Skip any implicit casts which could be either part of a narrowing conversion /// or after one in an implicit conversion. static const Expr *IgnoreNarrowingConversion(ASTContext &Ctx, const Expr *Converted) { // We can have cleanups wrapping the converted expression; these need to be // preserved so that destructors run if necessary. if (auto *EWC = dyn_cast(Converted)) { Expr *Inner = const_cast(IgnoreNarrowingConversion(Ctx, EWC->getSubExpr())); return ExprWithCleanups::Create(Ctx, Inner, EWC->cleanupsHaveSideEffects(), EWC->getObjects()); } while (auto *ICE = dyn_cast(Converted)) { switch (ICE->getCastKind()) { case CK_NoOp: case CK_IntegralCast: case CK_IntegralToBoolean: case CK_IntegralToFloating: case CK_BooleanToSignedIntegral: case CK_FloatingToIntegral: case CK_FloatingToBoolean: case CK_FloatingCast: Converted = ICE->getSubExpr(); continue; default: return Converted; } } return Converted; } /// Check if this standard conversion sequence represents a narrowing /// conversion, according to C++11 [dcl.init.list]p7. /// /// \param Ctx The AST context. /// \param Converted The result of applying this standard conversion sequence. /// \param ConstantValue If this is an NK_Constant_Narrowing conversion, the /// value of the expression prior to the narrowing conversion. /// \param ConstantType If this is an NK_Constant_Narrowing conversion, the /// type of the expression prior to the narrowing conversion. /// \param IgnoreFloatToIntegralConversion If true type-narrowing conversions /// from floating point types to integral types should be ignored. NarrowingKind StandardConversionSequence::getNarrowingKind( ASTContext &Ctx, const Expr *Converted, APValue &ConstantValue, QualType &ConstantType, bool IgnoreFloatToIntegralConversion) const { assert(Ctx.getLangOpts().CPlusPlus && "narrowing check outside C++"); // C++11 [dcl.init.list]p7: // A narrowing conversion is an implicit conversion ... QualType FromType = getToType(0); QualType ToType = getToType(1); // A conversion to an enumeration type is narrowing if the conversion to // the underlying type is narrowing. This only arises for expressions of // the form 'Enum{init}'. if (auto *ET = ToType->getAs()) ToType = ET->getDecl()->getIntegerType(); switch (Second) { // 'bool' is an integral type; dispatch to the right place to handle it. case ICK_Boolean_Conversion: if (FromType->isRealFloatingType()) goto FloatingIntegralConversion; if (FromType->isIntegralOrUnscopedEnumerationType()) goto IntegralConversion; // -- from a pointer type or pointer-to-member type to bool, or return NK_Type_Narrowing; // -- from a floating-point type to an integer type, or // // -- from an integer type or unscoped enumeration type to a floating-point // type, except where the source is a constant expression and the actual // value after conversion will fit into the target type and will produce // the original value when converted back to the original type, or case ICK_Floating_Integral: FloatingIntegralConversion: if (FromType->isRealFloatingType() && ToType->isIntegralType(Ctx)) { return NK_Type_Narrowing; } else if (FromType->isIntegralOrUnscopedEnumerationType() && ToType->isRealFloatingType()) { if (IgnoreFloatToIntegralConversion) return NK_Not_Narrowing; const Expr *Initializer = IgnoreNarrowingConversion(Ctx, Converted); assert(Initializer && "Unknown conversion expression"); // If it's value-dependent, we can't tell whether it's narrowing. if (Initializer->isValueDependent()) return NK_Dependent_Narrowing; if (Optional IntConstantValue = Initializer->getIntegerConstantExpr(Ctx)) { // Convert the integer to the floating type. llvm::APFloat Result(Ctx.getFloatTypeSemantics(ToType)); Result.convertFromAPInt(*IntConstantValue, IntConstantValue->isSigned(), llvm::APFloat::rmNearestTiesToEven); // And back. llvm::APSInt ConvertedValue = *IntConstantValue; bool ignored; Result.convertToInteger(ConvertedValue, llvm::APFloat::rmTowardZero, &ignored); // If the resulting value is different, this was a narrowing conversion. if (*IntConstantValue != ConvertedValue) { ConstantValue = APValue(*IntConstantValue); ConstantType = Initializer->getType(); return NK_Constant_Narrowing; } } else { // Variables are always narrowings. return NK_Variable_Narrowing; } } return NK_Not_Narrowing; // -- from long double to double or float, or from double to float, except // where the source is a constant expression and the actual value after // conversion is within the range of values that can be represented (even // if it cannot be represented exactly), or case ICK_Floating_Conversion: if (FromType->isRealFloatingType() && ToType->isRealFloatingType() && Ctx.getFloatingTypeOrder(FromType, ToType) == 1) { // FromType is larger than ToType. const Expr *Initializer = IgnoreNarrowingConversion(Ctx, Converted); // If it's value-dependent, we can't tell whether it's narrowing. if (Initializer->isValueDependent()) return NK_Dependent_Narrowing; if (Initializer->isCXX11ConstantExpr(Ctx, &ConstantValue)) { // Constant! assert(ConstantValue.isFloat()); llvm::APFloat FloatVal = ConstantValue.getFloat(); // Convert the source value into the target type. bool ignored; llvm::APFloat::opStatus ConvertStatus = FloatVal.convert( Ctx.getFloatTypeSemantics(ToType), llvm::APFloat::rmNearestTiesToEven, &ignored); // If there was no overflow, the source value is within the range of // values that can be represented. if (ConvertStatus & llvm::APFloat::opOverflow) { ConstantType = Initializer->getType(); return NK_Constant_Narrowing; } } else { return NK_Variable_Narrowing; } } return NK_Not_Narrowing; // -- from an integer type or unscoped enumeration type to an integer type // that cannot represent all the values of the original type, except where // the source is a constant expression and the actual value after // conversion will fit into the target type and will produce the original // value when converted back to the original type. case ICK_Integral_Conversion: IntegralConversion: { assert(FromType->isIntegralOrUnscopedEnumerationType()); assert(ToType->isIntegralOrUnscopedEnumerationType()); const bool FromSigned = FromType->isSignedIntegerOrEnumerationType(); const unsigned FromWidth = Ctx.getIntWidth(FromType); const bool ToSigned = ToType->isSignedIntegerOrEnumerationType(); const unsigned ToWidth = Ctx.getIntWidth(ToType); if (FromWidth > ToWidth || (FromWidth == ToWidth && FromSigned != ToSigned) || (FromSigned && !ToSigned)) { // Not all values of FromType can be represented in ToType. const Expr *Initializer = IgnoreNarrowingConversion(Ctx, Converted); // If it's value-dependent, we can't tell whether it's narrowing. if (Initializer->isValueDependent()) return NK_Dependent_Narrowing; Optional OptInitializerValue; if (!(OptInitializerValue = Initializer->getIntegerConstantExpr(Ctx))) { // Such conversions on variables are always narrowing. return NK_Variable_Narrowing; } llvm::APSInt &InitializerValue = *OptInitializerValue; bool Narrowing = false; if (FromWidth < ToWidth) { // Negative -> unsigned is narrowing. Otherwise, more bits is never // narrowing. if (InitializerValue.isSigned() && InitializerValue.isNegative()) Narrowing = true; } else { // Add a bit to the InitializerValue so we don't have to worry about // signed vs. unsigned comparisons. InitializerValue = InitializerValue.extend( InitializerValue.getBitWidth() + 1); // Convert the initializer to and from the target width and signed-ness. llvm::APSInt ConvertedValue = InitializerValue; ConvertedValue = ConvertedValue.trunc(ToWidth); ConvertedValue.setIsSigned(ToSigned); ConvertedValue = ConvertedValue.extend(InitializerValue.getBitWidth()); ConvertedValue.setIsSigned(InitializerValue.isSigned()); // If the result is different, this was a narrowing conversion. if (ConvertedValue != InitializerValue) Narrowing = true; } if (Narrowing) { ConstantType = Initializer->getType(); ConstantValue = APValue(InitializerValue); return NK_Constant_Narrowing; } } return NK_Not_Narrowing; } default: // Other kinds of conversions are not narrowings. return NK_Not_Narrowing; } } /// dump - Print this standard conversion sequence to standard /// error. Useful for debugging overloading issues. LLVM_DUMP_METHOD void StandardConversionSequence::dump() const { raw_ostream &OS = llvm::errs(); bool PrintedSomething = false; if (First != ICK_Identity) { OS << GetImplicitConversionName(First); PrintedSomething = true; } if (Second != ICK_Identity) { if (PrintedSomething) { OS << " -> "; } OS << GetImplicitConversionName(Second); if (CopyConstructor) { OS << " (by copy constructor)"; } else if (DirectBinding) { OS << " (direct reference binding)"; } else if (ReferenceBinding) { OS << " (reference binding)"; } PrintedSomething = true; } if (Third != ICK_Identity) { if (PrintedSomething) { OS << " -> "; } OS << GetImplicitConversionName(Third); PrintedSomething = true; } if (!PrintedSomething) { OS << "No conversions required"; } } /// dump - Print this user-defined conversion sequence to standard /// error. Useful for debugging overloading issues. void UserDefinedConversionSequence::dump() const { raw_ostream &OS = llvm::errs(); if (Before.First || Before.Second || Before.Third) { Before.dump(); OS << " -> "; } if (ConversionFunction) OS << '\'' << *ConversionFunction << '\''; else OS << "aggregate initialization"; if (After.First || After.Second || After.Third) { OS << " -> "; After.dump(); } } /// dump - Print this implicit conversion sequence to standard /// error. Useful for debugging overloading issues. void ImplicitConversionSequence::dump() const { raw_ostream &OS = llvm::errs(); if (isStdInitializerListElement()) OS << "Worst std::initializer_list element conversion: "; switch (ConversionKind) { case StandardConversion: OS << "Standard conversion: "; Standard.dump(); break; case UserDefinedConversion: OS << "User-defined conversion: "; UserDefined.dump(); break; case EllipsisConversion: OS << "Ellipsis conversion"; break; case AmbiguousConversion: OS << "Ambiguous conversion"; break; case BadConversion: OS << "Bad conversion"; break; } OS << "\n"; } void AmbiguousConversionSequence::construct() { new (&conversions()) ConversionSet(); } void AmbiguousConversionSequence::destruct() { conversions().~ConversionSet(); } void AmbiguousConversionSequence::copyFrom(const AmbiguousConversionSequence &O) { FromTypePtr = O.FromTypePtr; ToTypePtr = O.ToTypePtr; new (&conversions()) ConversionSet(O.conversions()); } namespace { // Structure used by DeductionFailureInfo to store // template argument information. struct DFIArguments { TemplateArgument FirstArg; TemplateArgument SecondArg; }; // Structure used by DeductionFailureInfo to store // template parameter and template argument information. struct DFIParamWithArguments : DFIArguments { TemplateParameter Param; }; // Structure used by DeductionFailureInfo to store template argument // information and the index of the problematic call argument. struct DFIDeducedMismatchArgs : DFIArguments { TemplateArgumentList *TemplateArgs; unsigned CallArgIndex; }; // Structure used by DeductionFailureInfo to store information about // unsatisfied constraints. struct CNSInfo { TemplateArgumentList *TemplateArgs; ConstraintSatisfaction Satisfaction; }; } /// Convert from Sema's representation of template deduction information /// to the form used in overload-candidate information. DeductionFailureInfo clang::MakeDeductionFailureInfo(ASTContext &Context, Sema::TemplateDeductionResult TDK, TemplateDeductionInfo &Info) { DeductionFailureInfo Result; Result.Result = static_cast(TDK); Result.HasDiagnostic = false; switch (TDK) { case Sema::TDK_Invalid: case Sema::TDK_InstantiationDepth: case Sema::TDK_TooManyArguments: case Sema::TDK_TooFewArguments: case Sema::TDK_MiscellaneousDeductionFailure: case Sema::TDK_CUDATargetMismatch: Result.Data = nullptr; break; case Sema::TDK_Incomplete: case Sema::TDK_InvalidExplicitArguments: Result.Data = Info.Param.getOpaqueValue(); break; case Sema::TDK_DeducedMismatch: case Sema::TDK_DeducedMismatchNested: { // FIXME: Should allocate from normal heap so that we can free this later. auto *Saved = new (Context) DFIDeducedMismatchArgs; Saved->FirstArg = Info.FirstArg; Saved->SecondArg = Info.SecondArg; Saved->TemplateArgs = Info.take(); Saved->CallArgIndex = Info.CallArgIndex; Result.Data = Saved; break; } case Sema::TDK_NonDeducedMismatch: { // FIXME: Should allocate from normal heap so that we can free this later. DFIArguments *Saved = new (Context) DFIArguments; Saved->FirstArg = Info.FirstArg; Saved->SecondArg = Info.SecondArg; Result.Data = Saved; break; } case Sema::TDK_IncompletePack: // FIXME: It's slightly wasteful to allocate two TemplateArguments for this. case Sema::TDK_Inconsistent: case Sema::TDK_Underqualified: { // FIXME: Should allocate from normal heap so that we can free this later. DFIParamWithArguments *Saved = new (Context) DFIParamWithArguments; Saved->Param = Info.Param; Saved->FirstArg = Info.FirstArg; Saved->SecondArg = Info.SecondArg; Result.Data = Saved; break; } case Sema::TDK_SubstitutionFailure: Result.Data = Info.take(); if (Info.hasSFINAEDiagnostic()) { PartialDiagnosticAt *Diag = new (Result.Diagnostic) PartialDiagnosticAt( SourceLocation(), PartialDiagnostic::NullDiagnostic()); Info.takeSFINAEDiagnostic(*Diag); Result.HasDiagnostic = true; } break; case Sema::TDK_ConstraintsNotSatisfied: { CNSInfo *Saved = new (Context) CNSInfo; Saved->TemplateArgs = Info.take(); Saved->Satisfaction = Info.AssociatedConstraintsSatisfaction; Result.Data = Saved; break; } case Sema::TDK_Success: case Sema::TDK_NonDependentConversionFailure: llvm_unreachable("not a deduction failure"); } return Result; } void DeductionFailureInfo::Destroy() { switch (static_cast(Result)) { case Sema::TDK_Success: case Sema::TDK_Invalid: case Sema::TDK_InstantiationDepth: case Sema::TDK_Incomplete: case Sema::TDK_TooManyArguments: case Sema::TDK_TooFewArguments: case Sema::TDK_InvalidExplicitArguments: case Sema::TDK_CUDATargetMismatch: case Sema::TDK_NonDependentConversionFailure: break; case Sema::TDK_IncompletePack: case Sema::TDK_Inconsistent: case Sema::TDK_Underqualified: case Sema::TDK_DeducedMismatch: case Sema::TDK_DeducedMismatchNested: case Sema::TDK_NonDeducedMismatch: // FIXME: Destroy the data? Data = nullptr; break; case Sema::TDK_SubstitutionFailure: // FIXME: Destroy the template argument list? Data = nullptr; if (PartialDiagnosticAt *Diag = getSFINAEDiagnostic()) { Diag->~PartialDiagnosticAt(); HasDiagnostic = false; } break; case Sema::TDK_ConstraintsNotSatisfied: // FIXME: Destroy the template argument list? Data = nullptr; if (PartialDiagnosticAt *Diag = getSFINAEDiagnostic()) { Diag->~PartialDiagnosticAt(); HasDiagnostic = false; } break; // Unhandled case Sema::TDK_MiscellaneousDeductionFailure: break; } } PartialDiagnosticAt *DeductionFailureInfo::getSFINAEDiagnostic() { if (HasDiagnostic) return static_cast(static_cast(Diagnostic)); return nullptr; } TemplateParameter DeductionFailureInfo::getTemplateParameter() { switch (static_cast(Result)) { case Sema::TDK_Success: case Sema::TDK_Invalid: case Sema::TDK_InstantiationDepth: case Sema::TDK_TooManyArguments: case Sema::TDK_TooFewArguments: case Sema::TDK_SubstitutionFailure: case Sema::TDK_DeducedMismatch: case Sema::TDK_DeducedMismatchNested: case Sema::TDK_NonDeducedMismatch: case Sema::TDK_CUDATargetMismatch: case Sema::TDK_NonDependentConversionFailure: case Sema::TDK_ConstraintsNotSatisfied: return TemplateParameter(); case Sema::TDK_Incomplete: case Sema::TDK_InvalidExplicitArguments: return TemplateParameter::getFromOpaqueValue(Data); case Sema::TDK_IncompletePack: case Sema::TDK_Inconsistent: case Sema::TDK_Underqualified: return static_cast(Data)->Param; // Unhandled case Sema::TDK_MiscellaneousDeductionFailure: break; } return TemplateParameter(); } TemplateArgumentList *DeductionFailureInfo::getTemplateArgumentList() { switch (static_cast(Result)) { case Sema::TDK_Success: case Sema::TDK_Invalid: case Sema::TDK_InstantiationDepth: case Sema::TDK_TooManyArguments: case Sema::TDK_TooFewArguments: case Sema::TDK_Incomplete: case Sema::TDK_IncompletePack: case Sema::TDK_InvalidExplicitArguments: case Sema::TDK_Inconsistent: case Sema::TDK_Underqualified: case Sema::TDK_NonDeducedMismatch: case Sema::TDK_CUDATargetMismatch: case Sema::TDK_NonDependentConversionFailure: return nullptr; case Sema::TDK_DeducedMismatch: case Sema::TDK_DeducedMismatchNested: return static_cast(Data)->TemplateArgs; case Sema::TDK_SubstitutionFailure: return static_cast(Data); case Sema::TDK_ConstraintsNotSatisfied: return static_cast(Data)->TemplateArgs; // Unhandled case Sema::TDK_MiscellaneousDeductionFailure: break; } return nullptr; } const TemplateArgument *DeductionFailureInfo::getFirstArg() { switch (static_cast(Result)) { case Sema::TDK_Success: case Sema::TDK_Invalid: case Sema::TDK_InstantiationDepth: case Sema::TDK_Incomplete: case Sema::TDK_TooManyArguments: case Sema::TDK_TooFewArguments: case Sema::TDK_InvalidExplicitArguments: case Sema::TDK_SubstitutionFailure: case Sema::TDK_CUDATargetMismatch: case Sema::TDK_NonDependentConversionFailure: case Sema::TDK_ConstraintsNotSatisfied: return nullptr; case Sema::TDK_IncompletePack: case Sema::TDK_Inconsistent: case Sema::TDK_Underqualified: case Sema::TDK_DeducedMismatch: case Sema::TDK_DeducedMismatchNested: case Sema::TDK_NonDeducedMismatch: return &static_cast(Data)->FirstArg; // Unhandled case Sema::TDK_MiscellaneousDeductionFailure: break; } return nullptr; } const TemplateArgument *DeductionFailureInfo::getSecondArg() { switch (static_cast(Result)) { case Sema::TDK_Success: case Sema::TDK_Invalid: case Sema::TDK_InstantiationDepth: case Sema::TDK_Incomplete: case Sema::TDK_IncompletePack: case Sema::TDK_TooManyArguments: case Sema::TDK_TooFewArguments: case Sema::TDK_InvalidExplicitArguments: case Sema::TDK_SubstitutionFailure: case Sema::TDK_CUDATargetMismatch: case Sema::TDK_NonDependentConversionFailure: case Sema::TDK_ConstraintsNotSatisfied: return nullptr; case Sema::TDK_Inconsistent: case Sema::TDK_Underqualified: case Sema::TDK_DeducedMismatch: case Sema::TDK_DeducedMismatchNested: case Sema::TDK_NonDeducedMismatch: return &static_cast(Data)->SecondArg; // Unhandled case Sema::TDK_MiscellaneousDeductionFailure: break; } return nullptr; } llvm::Optional DeductionFailureInfo::getCallArgIndex() { switch (static_cast(Result)) { case Sema::TDK_DeducedMismatch: case Sema::TDK_DeducedMismatchNested: return static_cast(Data)->CallArgIndex; default: return llvm::None; } } bool OverloadCandidateSet::OperatorRewriteInfo::shouldAddReversed( OverloadedOperatorKind Op) { if (!AllowRewrittenCandidates) return false; return Op == OO_EqualEqual || Op == OO_Spaceship; } bool OverloadCandidateSet::OperatorRewriteInfo::shouldAddReversed( ASTContext &Ctx, const FunctionDecl *FD) { if (!shouldAddReversed(FD->getDeclName().getCXXOverloadedOperator())) return false; // Don't bother adding a reversed candidate that can never be a better // match than the non-reversed version. return FD->getNumParams() != 2 || !Ctx.hasSameUnqualifiedType(FD->getParamDecl(0)->getType(), FD->getParamDecl(1)->getType()) || FD->hasAttr(); } void OverloadCandidateSet::destroyCandidates() { for (iterator i = begin(), e = end(); i != e; ++i) { for (auto &C : i->Conversions) C.~ImplicitConversionSequence(); if (!i->Viable && i->FailureKind == ovl_fail_bad_deduction) i->DeductionFailure.Destroy(); } } void OverloadCandidateSet::clear(CandidateSetKind CSK) { destroyCandidates(); SlabAllocator.Reset(); NumInlineBytesUsed = 0; Candidates.clear(); Functions.clear(); Kind = CSK; } namespace { class UnbridgedCastsSet { struct Entry { Expr **Addr; Expr *Saved; }; SmallVector Entries; public: void save(Sema &S, Expr *&E) { assert(E->hasPlaceholderType(BuiltinType::ARCUnbridgedCast)); Entry entry = { &E, E }; Entries.push_back(entry); E = S.stripARCUnbridgedCast(E); } void restore() { for (SmallVectorImpl::iterator i = Entries.begin(), e = Entries.end(); i != e; ++i) *i->Addr = i->Saved; } }; } /// checkPlaceholderForOverload - Do any interesting placeholder-like /// preprocessing on the given expression. /// /// \param unbridgedCasts a collection to which to add unbridged casts; /// without this, they will be immediately diagnosed as errors /// /// Return true on unrecoverable error. static bool checkPlaceholderForOverload(Sema &S, Expr *&E, UnbridgedCastsSet *unbridgedCasts = nullptr) { if (const BuiltinType *placeholder = E->getType()->getAsPlaceholderType()) { // We can't handle overloaded expressions here because overload // resolution might reasonably tweak them. if (placeholder->getKind() == BuiltinType::Overload) return false; // If the context potentially accepts unbridged ARC casts, strip // the unbridged cast and add it to the collection for later restoration. if (placeholder->getKind() == BuiltinType::ARCUnbridgedCast && unbridgedCasts) { unbridgedCasts->save(S, E); return false; } // Go ahead and check everything else. ExprResult result = S.CheckPlaceholderExpr(E); if (result.isInvalid()) return true; E = result.get(); return false; } // Nothing to do. return false; } /// checkArgPlaceholdersForOverload - Check a set of call operands for /// placeholders. static bool checkArgPlaceholdersForOverload(Sema &S, MultiExprArg Args, UnbridgedCastsSet &unbridged) { for (unsigned i = 0, e = Args.size(); i != e; ++i) if (checkPlaceholderForOverload(S, Args[i], &unbridged)) return true; return false; } /// Determine whether the given New declaration is an overload of the /// declarations in Old. This routine returns Ovl_Match or Ovl_NonFunction if /// New and Old cannot be overloaded, e.g., if New has the same signature as /// some function in Old (C++ 1.3.10) or if the Old declarations aren't /// functions (or function templates) at all. When it does return Ovl_Match or /// Ovl_NonFunction, MatchedDecl will point to the decl that New cannot be /// overloaded with. This decl may be a UsingShadowDecl on top of the underlying /// declaration. /// /// Example: Given the following input: /// /// void f(int, float); // #1 /// void f(int, int); // #2 /// int f(int, int); // #3 /// /// When we process #1, there is no previous declaration of "f", so IsOverload /// will not be used. /// /// When we process #2, Old contains only the FunctionDecl for #1. By comparing /// the parameter types, we see that #1 and #2 are overloaded (since they have /// different signatures), so this routine returns Ovl_Overload; MatchedDecl is /// unchanged. /// /// When we process #3, Old is an overload set containing #1 and #2. We compare /// the signatures of #3 to #1 (they're overloaded, so we do nothing) and then /// #3 to #2. Since the signatures of #3 and #2 are identical (return types of /// functions are not part of the signature), IsOverload returns Ovl_Match and /// MatchedDecl will be set to point to the FunctionDecl for #2. /// /// 'NewIsUsingShadowDecl' indicates that 'New' is being introduced into a class /// by a using declaration. The rules for whether to hide shadow declarations /// ignore some properties which otherwise figure into a function template's /// signature. Sema::OverloadKind Sema::CheckOverload(Scope *S, FunctionDecl *New, const LookupResult &Old, NamedDecl *&Match, bool NewIsUsingDecl) { for (LookupResult::iterator I = Old.begin(), E = Old.end(); I != E; ++I) { NamedDecl *OldD = *I; bool OldIsUsingDecl = false; if (isa(OldD)) { OldIsUsingDecl = true; // We can always introduce two using declarations into the same // context, even if they have identical signatures. if (NewIsUsingDecl) continue; OldD = cast(OldD)->getTargetDecl(); } // A using-declaration does not conflict with another declaration // if one of them is hidden. if ((OldIsUsingDecl || NewIsUsingDecl) && !isVisible(*I)) continue; // If either declaration was introduced by a using declaration, // we'll need to use slightly different rules for matching. // Essentially, these rules are the normal rules, except that // function templates hide function templates with different // return types or template parameter lists. bool UseMemberUsingDeclRules = (OldIsUsingDecl || NewIsUsingDecl) && CurContext->isRecord() && !New->getFriendObjectKind(); if (FunctionDecl *OldF = OldD->getAsFunction()) { if (!IsOverload(New, OldF, UseMemberUsingDeclRules)) { if (UseMemberUsingDeclRules && OldIsUsingDecl) { HideUsingShadowDecl(S, cast(*I)); continue; } if (!isa(OldD) && !shouldLinkPossiblyHiddenDecl(*I, New)) continue; Match = *I; return Ovl_Match; } // Builtins that have custom typechecking or have a reference should // not be overloadable or redeclarable. if (!getASTContext().canBuiltinBeRedeclared(OldF)) { Match = *I; return Ovl_NonFunction; } } else if (isa(OldD) || isa(OldD)) { // We can overload with these, which can show up when doing // redeclaration checks for UsingDecls. assert(Old.getLookupKind() == LookupUsingDeclName); } else if (isa(OldD)) { // We can always overload with tags by hiding them. } else if (auto *UUD = dyn_cast(OldD)) { // Optimistically assume that an unresolved using decl will // overload; if it doesn't, we'll have to diagnose during // template instantiation. // // Exception: if the scope is dependent and this is not a class // member, the using declaration can only introduce an enumerator. if (UUD->getQualifier()->isDependent() && !UUD->isCXXClassMember()) { Match = *I; return Ovl_NonFunction; } } else { // (C++ 13p1): // Only function declarations can be overloaded; object and type // declarations cannot be overloaded. Match = *I; return Ovl_NonFunction; } } // C++ [temp.friend]p1: // For a friend function declaration that is not a template declaration: // -- if the name of the friend is a qualified or unqualified template-id, // [...], otherwise // -- if the name of the friend is a qualified-id and a matching // non-template function is found in the specified class or namespace, // the friend declaration refers to that function, otherwise, // -- if the name of the friend is a qualified-id and a matching function // template is found in the specified class or namespace, the friend // declaration refers to the deduced specialization of that function // template, otherwise // -- the name shall be an unqualified-id [...] // If we get here for a qualified friend declaration, we've just reached the // third bullet. If the type of the friend is dependent, skip this lookup // until instantiation. if (New->getFriendObjectKind() && New->getQualifier() && !New->getDescribedFunctionTemplate() && !New->getDependentSpecializationInfo() && !New->getType()->isDependentType()) { LookupResult TemplateSpecResult(LookupResult::Temporary, Old); TemplateSpecResult.addAllDecls(Old); if (CheckFunctionTemplateSpecialization(New, nullptr, TemplateSpecResult, /*QualifiedFriend*/true)) { New->setInvalidDecl(); return Ovl_Overload; } Match = TemplateSpecResult.getAsSingle(); return Ovl_Match; } return Ovl_Overload; } bool Sema::IsOverload(FunctionDecl *New, FunctionDecl *Old, bool UseMemberUsingDeclRules, bool ConsiderCudaAttrs, bool ConsiderRequiresClauses) { // C++ [basic.start.main]p2: This function shall not be overloaded. if (New->isMain()) return false; // MSVCRT user defined entry points cannot be overloaded. if (New->isMSVCRTEntryPoint()) return false; FunctionTemplateDecl *OldTemplate = Old->getDescribedFunctionTemplate(); FunctionTemplateDecl *NewTemplate = New->getDescribedFunctionTemplate(); // C++ [temp.fct]p2: // A function template can be overloaded with other function templates // and with normal (non-template) functions. if ((OldTemplate == nullptr) != (NewTemplate == nullptr)) return true; // Is the function New an overload of the function Old? QualType OldQType = Context.getCanonicalType(Old->getType()); QualType NewQType = Context.getCanonicalType(New->getType()); // Compare the signatures (C++ 1.3.10) of the two functions to // determine whether they are overloads. If we find any mismatch // in the signature, they are overloads. // If either of these functions is a K&R-style function (no // prototype), then we consider them to have matching signatures. if (isa(OldQType.getTypePtr()) || isa(NewQType.getTypePtr())) return false; const FunctionProtoType *OldType = cast(OldQType); const FunctionProtoType *NewType = cast(NewQType); // The signature of a function includes the types of its // parameters (C++ 1.3.10), which includes the presence or absence // of the ellipsis; see C++ DR 357). if (OldQType != NewQType && (OldType->getNumParams() != NewType->getNumParams() || OldType->isVariadic() != NewType->isVariadic() || !FunctionParamTypesAreEqual(OldType, NewType))) return true; // C++ [temp.over.link]p4: // The signature of a function template consists of its function // signature, its return type and its template parameter list. The names // of the template parameters are significant only for establishing the // relationship between the template parameters and the rest of the // signature. // // We check the return type and template parameter lists for function // templates first; the remaining checks follow. // // However, we don't consider either of these when deciding whether // a member introduced by a shadow declaration is hidden. if (!UseMemberUsingDeclRules && NewTemplate && (!TemplateParameterListsAreEqual(NewTemplate->getTemplateParameters(), OldTemplate->getTemplateParameters(), false, TPL_TemplateMatch) || !Context.hasSameType(Old->getDeclaredReturnType(), New->getDeclaredReturnType()))) return true; // If the function is a class member, its signature includes the // cv-qualifiers (if any) and ref-qualifier (if any) on the function itself. // // As part of this, also check whether one of the member functions // is static, in which case they are not overloads (C++ // 13.1p2). While not part of the definition of the signature, // this check is important to determine whether these functions // can be overloaded. CXXMethodDecl *OldMethod = dyn_cast(Old); CXXMethodDecl *NewMethod = dyn_cast(New); if (OldMethod && NewMethod && !OldMethod->isStatic() && !NewMethod->isStatic()) { if (OldMethod->getRefQualifier() != NewMethod->getRefQualifier()) { if (!UseMemberUsingDeclRules && (OldMethod->getRefQualifier() == RQ_None || NewMethod->getRefQualifier() == RQ_None)) { // C++0x [over.load]p2: // - Member function declarations with the same name and the same // parameter-type-list as well as member function template // declarations with the same name, the same parameter-type-list, and // the same template parameter lists cannot be overloaded if any of // them, but not all, have a ref-qualifier (8.3.5). Diag(NewMethod->getLocation(), diag::err_ref_qualifier_overload) << NewMethod->getRefQualifier() << OldMethod->getRefQualifier(); Diag(OldMethod->getLocation(), diag::note_previous_declaration); } return true; } // We may not have applied the implicit const for a constexpr member // function yet (because we haven't yet resolved whether this is a static // or non-static member function). Add it now, on the assumption that this // is a redeclaration of OldMethod. auto OldQuals = OldMethod->getMethodQualifiers(); auto NewQuals = NewMethod->getMethodQualifiers(); if (!getLangOpts().CPlusPlus14 && NewMethod->isConstexpr() && !isa(NewMethod)) NewQuals.addConst(); // We do not allow overloading based off of '__restrict'. OldQuals.removeRestrict(); NewQuals.removeRestrict(); if (OldQuals != NewQuals) return true; } // Though pass_object_size is placed on parameters and takes an argument, we // consider it to be a function-level modifier for the sake of function // identity. Either the function has one or more parameters with // pass_object_size or it doesn't. if (functionHasPassObjectSizeParams(New) != functionHasPassObjectSizeParams(Old)) return true; // enable_if attributes are an order-sensitive part of the signature. for (specific_attr_iterator NewI = New->specific_attr_begin(), NewE = New->specific_attr_end(), OldI = Old->specific_attr_begin(), OldE = Old->specific_attr_end(); NewI != NewE || OldI != OldE; ++NewI, ++OldI) { if (NewI == NewE || OldI == OldE) return true; llvm::FoldingSetNodeID NewID, OldID; NewI->getCond()->Profile(NewID, Context, true); OldI->getCond()->Profile(OldID, Context, true); if (NewID != OldID) return true; } if (getLangOpts().CUDA && ConsiderCudaAttrs) { // Don't allow overloading of destructors. (In theory we could, but it // would be a giant change to clang.) if (!isa(New)) { CUDAFunctionTarget NewTarget = IdentifyCUDATarget(New), OldTarget = IdentifyCUDATarget(Old); if (NewTarget != CFT_InvalidTarget) { assert((OldTarget != CFT_InvalidTarget) && "Unexpected invalid target."); // Allow overloading of functions with same signature and different CUDA // target attributes. if (NewTarget != OldTarget) return true; } } } if (ConsiderRequiresClauses) { Expr *NewRC = New->getTrailingRequiresClause(), *OldRC = Old->getTrailingRequiresClause(); if ((NewRC != nullptr) != (OldRC != nullptr)) // RC are most certainly different - these are overloads. return true; if (NewRC) { llvm::FoldingSetNodeID NewID, OldID; NewRC->Profile(NewID, Context, /*Canonical=*/true); OldRC->Profile(OldID, Context, /*Canonical=*/true); if (NewID != OldID) // RCs are not equivalent - these are overloads. return true; } } // The signatures match; this is not an overload. return false; } /// Tries a user-defined conversion from From to ToType. /// /// Produces an implicit conversion sequence for when a standard conversion /// is not an option. See TryImplicitConversion for more information. static ImplicitConversionSequence TryUserDefinedConversion(Sema &S, Expr *From, QualType ToType, bool SuppressUserConversions, AllowedExplicit AllowExplicit, bool InOverloadResolution, bool CStyle, bool AllowObjCWritebackConversion, bool AllowObjCConversionOnExplicit) { ImplicitConversionSequence ICS; if (SuppressUserConversions) { // We're not in the case above, so there is no conversion that // we can perform. ICS.setBad(BadConversionSequence::no_conversion, From, ToType); return ICS; } // Attempt user-defined conversion. OverloadCandidateSet Conversions(From->getExprLoc(), OverloadCandidateSet::CSK_Normal); switch (IsUserDefinedConversion(S, From, ToType, ICS.UserDefined, Conversions, AllowExplicit, AllowObjCConversionOnExplicit)) { case OR_Success: case OR_Deleted: ICS.setUserDefined(); // C++ [over.ics.user]p4: // A conversion of an expression of class type to the same class // type is given Exact Match rank, and a conversion of an // expression of class type to a base class of that type is // given Conversion rank, in spite of the fact that a copy // constructor (i.e., a user-defined conversion function) is // called for those cases. if (CXXConstructorDecl *Constructor = dyn_cast(ICS.UserDefined.ConversionFunction)) { QualType FromCanon = S.Context.getCanonicalType(From->getType().getUnqualifiedType()); QualType ToCanon = S.Context.getCanonicalType(ToType).getUnqualifiedType(); if (Constructor->isCopyConstructor() && (FromCanon == ToCanon || S.IsDerivedFrom(From->getBeginLoc(), FromCanon, ToCanon))) { // Turn this into a "standard" conversion sequence, so that it // gets ranked with standard conversion sequences. DeclAccessPair Found = ICS.UserDefined.FoundConversionFunction; ICS.setStandard(); ICS.Standard.setAsIdentityConversion(); ICS.Standard.setFromType(From->getType()); ICS.Standard.setAllToTypes(ToType); ICS.Standard.CopyConstructor = Constructor; ICS.Standard.FoundCopyConstructor = Found; if (ToCanon != FromCanon) ICS.Standard.Second = ICK_Derived_To_Base; } } break; case OR_Ambiguous: ICS.setAmbiguous(); ICS.Ambiguous.setFromType(From->getType()); ICS.Ambiguous.setToType(ToType); for (OverloadCandidateSet::iterator Cand = Conversions.begin(); Cand != Conversions.end(); ++Cand) if (Cand->Best) ICS.Ambiguous.addConversion(Cand->FoundDecl, Cand->Function); break; // Fall through. case OR_No_Viable_Function: ICS.setBad(BadConversionSequence::no_conversion, From, ToType); break; } return ICS; } /// TryImplicitConversion - Attempt to perform an implicit conversion /// from the given expression (Expr) to the given type (ToType). This /// function returns an implicit conversion sequence that can be used /// to perform the initialization. Given /// /// void f(float f); /// void g(int i) { f(i); } /// /// this routine would produce an implicit conversion sequence to /// describe the initialization of f from i, which will be a standard /// conversion sequence containing an lvalue-to-rvalue conversion (C++ /// 4.1) followed by a floating-integral conversion (C++ 4.9). // /// Note that this routine only determines how the conversion can be /// performed; it does not actually perform the conversion. As such, /// it will not produce any diagnostics if no conversion is available, /// but will instead return an implicit conversion sequence of kind /// "BadConversion". /// /// If @p SuppressUserConversions, then user-defined conversions are /// not permitted. /// If @p AllowExplicit, then explicit user-defined conversions are /// permitted. /// /// \param AllowObjCWritebackConversion Whether we allow the Objective-C /// writeback conversion, which allows __autoreleasing id* parameters to /// be initialized with __strong id* or __weak id* arguments. static ImplicitConversionSequence TryImplicitConversion(Sema &S, Expr *From, QualType ToType, bool SuppressUserConversions, AllowedExplicit AllowExplicit, bool InOverloadResolution, bool CStyle, bool AllowObjCWritebackConversion, bool AllowObjCConversionOnExplicit) { ImplicitConversionSequence ICS; if (IsStandardConversion(S, From, ToType, InOverloadResolution, ICS.Standard, CStyle, AllowObjCWritebackConversion)){ ICS.setStandard(); return ICS; } if (!S.getLangOpts().CPlusPlus) { ICS.setBad(BadConversionSequence::no_conversion, From, ToType); return ICS; } // C++ [over.ics.user]p4: // A conversion of an expression of class type to the same class // type is given Exact Match rank, and a conversion of an // expression of class type to a base class of that type is // given Conversion rank, in spite of the fact that a copy/move // constructor (i.e., a user-defined conversion function) is // called for those cases. QualType FromType = From->getType(); if (ToType->getAs() && FromType->getAs() && (S.Context.hasSameUnqualifiedType(FromType, ToType) || S.IsDerivedFrom(From->getBeginLoc(), FromType, ToType))) { ICS.setStandard(); ICS.Standard.setAsIdentityConversion(); ICS.Standard.setFromType(FromType); ICS.Standard.setAllToTypes(ToType); // We don't actually check at this point whether there is a valid // copy/move constructor, since overloading just assumes that it // exists. When we actually perform initialization, we'll find the // appropriate constructor to copy the returned object, if needed. ICS.Standard.CopyConstructor = nullptr; // Determine whether this is considered a derived-to-base conversion. if (!S.Context.hasSameUnqualifiedType(FromType, ToType)) ICS.Standard.Second = ICK_Derived_To_Base; return ICS; } return TryUserDefinedConversion(S, From, ToType, SuppressUserConversions, AllowExplicit, InOverloadResolution, CStyle, AllowObjCWritebackConversion, AllowObjCConversionOnExplicit); } ImplicitConversionSequence Sema::TryImplicitConversion(Expr *From, QualType ToType, bool SuppressUserConversions, AllowedExplicit AllowExplicit, bool InOverloadResolution, bool CStyle, bool AllowObjCWritebackConversion) { return ::TryImplicitConversion(*this, From, ToType, SuppressUserConversions, AllowExplicit, InOverloadResolution, CStyle, AllowObjCWritebackConversion, /*AllowObjCConversionOnExplicit=*/false); } /// PerformImplicitConversion - Perform an implicit conversion of the /// expression From to the type ToType. Returns the /// converted expression. Flavor is the kind of conversion we're /// performing, used in the error message. If @p AllowExplicit, /// explicit user-defined conversions are permitted. ExprResult Sema::PerformImplicitConversion(Expr *From, QualType ToType, AssignmentAction Action, bool AllowExplicit) { if (checkPlaceholderForOverload(*this, From)) return ExprError(); // Objective-C ARC: Determine whether we will allow the writeback conversion. bool AllowObjCWritebackConversion = getLangOpts().ObjCAutoRefCount && (Action == AA_Passing || Action == AA_Sending); if (getLangOpts().ObjC) CheckObjCBridgeRelatedConversions(From->getBeginLoc(), ToType, From->getType(), From); ImplicitConversionSequence ICS = ::TryImplicitConversion( *this, From, ToType, /*SuppressUserConversions=*/false, AllowExplicit ? AllowedExplicit::All : AllowedExplicit::None, /*InOverloadResolution=*/false, /*CStyle=*/false, AllowObjCWritebackConversion, /*AllowObjCConversionOnExplicit=*/false); return PerformImplicitConversion(From, ToType, ICS, Action); } /// Determine whether the conversion from FromType to ToType is a valid /// conversion that strips "noexcept" or "noreturn" off the nested function /// type. bool Sema::IsFunctionConversion(QualType FromType, QualType ToType, QualType &ResultTy) { if (Context.hasSameUnqualifiedType(FromType, ToType)) return false; // Permit the conversion F(t __attribute__((noreturn))) -> F(t) // or F(t noexcept) -> F(t) // where F adds one of the following at most once: // - a pointer // - a member pointer // - a block pointer // Changes here need matching changes in FindCompositePointerType. CanQualType CanTo = Context.getCanonicalType(ToType); CanQualType CanFrom = Context.getCanonicalType(FromType); Type::TypeClass TyClass = CanTo->getTypeClass(); if (TyClass != CanFrom->getTypeClass()) return false; if (TyClass != Type::FunctionProto && TyClass != Type::FunctionNoProto) { if (TyClass == Type::Pointer) { CanTo = CanTo.castAs()->getPointeeType(); CanFrom = CanFrom.castAs()->getPointeeType(); } else if (TyClass == Type::BlockPointer) { CanTo = CanTo.castAs()->getPointeeType(); CanFrom = CanFrom.castAs()->getPointeeType(); } else if (TyClass == Type::MemberPointer) { auto ToMPT = CanTo.castAs(); auto FromMPT = CanFrom.castAs(); // A function pointer conversion cannot change the class of the function. if (ToMPT->getClass() != FromMPT->getClass()) return false; CanTo = ToMPT->getPointeeType(); CanFrom = FromMPT->getPointeeType(); } else { return false; } TyClass = CanTo->getTypeClass(); if (TyClass != CanFrom->getTypeClass()) return false; if (TyClass != Type::FunctionProto && TyClass != Type::FunctionNoProto) return false; } const auto *FromFn = cast(CanFrom); FunctionType::ExtInfo FromEInfo = FromFn->getExtInfo(); const auto *ToFn = cast(CanTo); FunctionType::ExtInfo ToEInfo = ToFn->getExtInfo(); bool Changed = false; // Drop 'noreturn' if not present in target type. if (FromEInfo.getNoReturn() && !ToEInfo.getNoReturn()) { FromFn = Context.adjustFunctionType(FromFn, FromEInfo.withNoReturn(false)); Changed = true; } // Drop 'noexcept' if not present in target type. if (const auto *FromFPT = dyn_cast(FromFn)) { const auto *ToFPT = cast(ToFn); if (FromFPT->isNothrow() && !ToFPT->isNothrow()) { FromFn = cast( Context.getFunctionTypeWithExceptionSpec(QualType(FromFPT, 0), EST_None) .getTypePtr()); Changed = true; } // Convert FromFPT's ExtParameterInfo if necessary. The conversion is valid // only if the ExtParameterInfo lists of the two function prototypes can be // merged and the merged list is identical to ToFPT's ExtParameterInfo list. SmallVector NewParamInfos; bool CanUseToFPT, CanUseFromFPT; if (Context.mergeExtParameterInfo(ToFPT, FromFPT, CanUseToFPT, CanUseFromFPT, NewParamInfos) && CanUseToFPT && !CanUseFromFPT) { FunctionProtoType::ExtProtoInfo ExtInfo = FromFPT->getExtProtoInfo(); ExtInfo.ExtParameterInfos = NewParamInfos.empty() ? nullptr : NewParamInfos.data(); QualType QT = Context.getFunctionType(FromFPT->getReturnType(), FromFPT->getParamTypes(), ExtInfo); FromFn = QT->getAs(); Changed = true; } } if (!Changed) return false; assert(QualType(FromFn, 0).isCanonical()); if (QualType(FromFn, 0) != CanTo) return false; ResultTy = ToType; return true; } /// Determine whether the conversion from FromType to ToType is a valid /// vector conversion. /// /// \param ICK Will be set to the vector conversion kind, if this is a vector /// conversion. static bool IsVectorConversion(Sema &S, QualType FromType, QualType ToType, ImplicitConversionKind &ICK) { // We need at least one of these types to be a vector type to have a vector // conversion. if (!ToType->isVectorType() && !FromType->isVectorType()) return false; // Identical types require no conversions. if (S.Context.hasSameUnqualifiedType(FromType, ToType)) return false; // There are no conversions between extended vector types, only identity. if (ToType->isExtVectorType()) { // There are no conversions between extended vector types other than the // identity conversion. if (FromType->isExtVectorType()) return false; // Vector splat from any arithmetic type to a vector. if (FromType->isArithmeticType()) { ICK = ICK_Vector_Splat; return true; } } if (ToType->isSizelessBuiltinType() || FromType->isSizelessBuiltinType()) if (S.Context.areCompatibleSveTypes(FromType, ToType) || S.Context.areLaxCompatibleSveTypes(FromType, ToType)) { ICK = ICK_SVE_Vector_Conversion; return true; } // We can perform the conversion between vector types in the following cases: // 1)vector types are equivalent AltiVec and GCC vector types // 2)lax vector conversions are permitted and the vector types are of the // same size // 3)the destination type does not have the ARM MVE strict-polymorphism // attribute, which inhibits lax vector conversion for overload resolution // only if (ToType->isVectorType() && FromType->isVectorType()) { if (S.Context.areCompatibleVectorTypes(FromType, ToType) || (S.isLaxVectorConversion(FromType, ToType) && !ToType->hasAttr(attr::ArmMveStrictPolymorphism))) { ICK = ICK_Vector_Conversion; return true; } } return false; } static bool tryAtomicConversion(Sema &S, Expr *From, QualType ToType, bool InOverloadResolution, StandardConversionSequence &SCS, bool CStyle); /// IsStandardConversion - Determines whether there is a standard /// conversion sequence (C++ [conv], C++ [over.ics.scs]) from the /// expression From to the type ToType. Standard conversion sequences /// only consider non-class types; for conversions that involve class /// types, use TryImplicitConversion. If a conversion exists, SCS will /// contain the standard conversion sequence required to perform this /// conversion and this routine will return true. Otherwise, this /// routine will return false and the value of SCS is unspecified. static bool IsStandardConversion(Sema &S, Expr* From, QualType ToType, bool InOverloadResolution, StandardConversionSequence &SCS, bool CStyle, bool AllowObjCWritebackConversion) { QualType FromType = From->getType(); // Standard conversions (C++ [conv]) SCS.setAsIdentityConversion(); SCS.IncompatibleObjC = false; SCS.setFromType(FromType); SCS.CopyConstructor = nullptr; // There are no standard conversions for class types in C++, so // abort early. When overloading in C, however, we do permit them. if (S.getLangOpts().CPlusPlus && (FromType->isRecordType() || ToType->isRecordType())) return false; // The first conversion can be an lvalue-to-rvalue conversion, // array-to-pointer conversion, or function-to-pointer conversion // (C++ 4p1). if (FromType == S.Context.OverloadTy) { DeclAccessPair AccessPair; if (FunctionDecl *Fn = S.ResolveAddressOfOverloadedFunction(From, ToType, false, AccessPair)) { // We were able to resolve the address of the overloaded function, // so we can convert to the type of that function. FromType = Fn->getType(); SCS.setFromType(FromType); // we can sometimes resolve &foo regardless of ToType, so check // if the type matches (identity) or we are converting to bool if (!S.Context.hasSameUnqualifiedType( S.ExtractUnqualifiedFunctionType(ToType), FromType)) { QualType resultTy; // if the function type matches except for [[noreturn]], it's ok if (!S.IsFunctionConversion(FromType, S.ExtractUnqualifiedFunctionType(ToType), resultTy)) // otherwise, only a boolean conversion is standard if (!ToType->isBooleanType()) return false; } // Check if the "from" expression is taking the address of an overloaded // function and recompute the FromType accordingly. Take advantage of the // fact that non-static member functions *must* have such an address-of // expression. CXXMethodDecl *Method = dyn_cast(Fn); if (Method && !Method->isStatic()) { assert(isa(From->IgnoreParens()) && "Non-unary operator on non-static member address"); assert(cast(From->IgnoreParens())->getOpcode() == UO_AddrOf && "Non-address-of operator on non-static member address"); const Type *ClassType = S.Context.getTypeDeclType(Method->getParent()).getTypePtr(); FromType = S.Context.getMemberPointerType(FromType, ClassType); } else if (isa(From->IgnoreParens())) { assert(cast(From->IgnoreParens())->getOpcode() == UO_AddrOf && "Non-address-of operator for overloaded function expression"); FromType = S.Context.getPointerType(FromType); } // Check that we've computed the proper type after overload resolution. // FIXME: FixOverloadedFunctionReference has side-effects; we shouldn't // be calling it from within an NDEBUG block. assert(S.Context.hasSameType( FromType, S.FixOverloadedFunctionReference(From, AccessPair, Fn)->getType())); } else { return false; } } // Lvalue-to-rvalue conversion (C++11 4.1): // A glvalue (3.10) of a non-function, non-array type T can // be converted to a prvalue. bool argIsLValue = From->isGLValue(); if (argIsLValue && !FromType->isFunctionType() && !FromType->isArrayType() && S.Context.getCanonicalType(FromType) != S.Context.OverloadTy) { SCS.First = ICK_Lvalue_To_Rvalue; // C11 6.3.2.1p2: // ... if the lvalue has atomic type, the value has the non-atomic version // of the type of the lvalue ... if (const AtomicType *Atomic = FromType->getAs()) FromType = Atomic->getValueType(); // If T is a non-class type, the type of the rvalue is the // cv-unqualified version of T. Otherwise, the type of the rvalue // is T (C++ 4.1p1). C++ can't get here with class types; in C, we // just strip the qualifiers because they don't matter. FromType = FromType.getUnqualifiedType(); } else if (FromType->isArrayType()) { // Array-to-pointer conversion (C++ 4.2) SCS.First = ICK_Array_To_Pointer; // An lvalue or rvalue of type "array of N T" or "array of unknown // bound of T" can be converted to an rvalue of type "pointer to // T" (C++ 4.2p1). FromType = S.Context.getArrayDecayedType(FromType); if (S.IsStringLiteralToNonConstPointerConversion(From, ToType)) { // This conversion is deprecated in C++03 (D.4) SCS.DeprecatedStringLiteralToCharPtr = true; // For the purpose of ranking in overload resolution // (13.3.3.1.1), this conversion is considered an // array-to-pointer conversion followed by a qualification // conversion (4.4). (C++ 4.2p2) SCS.Second = ICK_Identity; SCS.Third = ICK_Qualification; SCS.QualificationIncludesObjCLifetime = false; SCS.setAllToTypes(FromType); return true; } } else if (FromType->isFunctionType() && argIsLValue) { // Function-to-pointer conversion (C++ 4.3). SCS.First = ICK_Function_To_Pointer; if (auto *DRE = dyn_cast(From->IgnoreParenCasts())) if (auto *FD = dyn_cast(DRE->getDecl())) if (!S.checkAddressOfFunctionIsAvailable(FD)) return false; // An lvalue of function type T can be converted to an rvalue of // type "pointer to T." The result is a pointer to the // function. (C++ 4.3p1). FromType = S.Context.getPointerType(FromType); } else { // We don't require any conversions for the first step. SCS.First = ICK_Identity; } SCS.setToType(0, FromType); // The second conversion can be an integral promotion, floating // point promotion, integral conversion, floating point conversion, // floating-integral conversion, pointer conversion, // pointer-to-member conversion, or boolean conversion (C++ 4p1). // For overloading in C, this can also be a "compatible-type" // conversion. bool IncompatibleObjC = false; ImplicitConversionKind SecondICK = ICK_Identity; if (S.Context.hasSameUnqualifiedType(FromType, ToType)) { // The unqualified versions of the types are the same: there's no // conversion to do. SCS.Second = ICK_Identity; } else if (S.IsIntegralPromotion(From, FromType, ToType)) { // Integral promotion (C++ 4.5). SCS.Second = ICK_Integral_Promotion; FromType = ToType.getUnqualifiedType(); } else if (S.IsFloatingPointPromotion(FromType, ToType)) { // Floating point promotion (C++ 4.6). SCS.Second = ICK_Floating_Promotion; FromType = ToType.getUnqualifiedType(); } else if (S.IsComplexPromotion(FromType, ToType)) { // Complex promotion (Clang extension) SCS.Second = ICK_Complex_Promotion; FromType = ToType.getUnqualifiedType(); } else if (ToType->isBooleanType() && (FromType->isArithmeticType() || FromType->isAnyPointerType() || FromType->isBlockPointerType() || FromType->isMemberPointerType())) { // Boolean conversions (C++ 4.12). SCS.Second = ICK_Boolean_Conversion; FromType = S.Context.BoolTy; } else if (FromType->isIntegralOrUnscopedEnumerationType() && ToType->isIntegralType(S.Context)) { // Integral conversions (C++ 4.7). SCS.Second = ICK_Integral_Conversion; FromType = ToType.getUnqualifiedType(); } else if (FromType->isAnyComplexType() && ToType->isAnyComplexType()) { // Complex conversions (C99 6.3.1.6) SCS.Second = ICK_Complex_Conversion; FromType = ToType.getUnqualifiedType(); } else if ((FromType->isAnyComplexType() && ToType->isArithmeticType()) || (ToType->isAnyComplexType() && FromType->isArithmeticType())) { // Complex-real conversions (C99 6.3.1.7) SCS.Second = ICK_Complex_Real; FromType = ToType.getUnqualifiedType(); } else if (FromType->isRealFloatingType() && ToType->isRealFloatingType()) { // FIXME: disable conversions between long double and __float128 if // their representation is different until there is back end support // We of course allow this conversion if long double is really double. // Conversions between bfloat and other floats are not permitted. if (FromType == S.Context.BFloat16Ty || ToType == S.Context.BFloat16Ty) return false; if (&S.Context.getFloatTypeSemantics(FromType) != &S.Context.getFloatTypeSemantics(ToType)) { bool Float128AndLongDouble = ((FromType == S.Context.Float128Ty && ToType == S.Context.LongDoubleTy) || (FromType == S.Context.LongDoubleTy && ToType == S.Context.Float128Ty)); if (Float128AndLongDouble && (&S.Context.getFloatTypeSemantics(S.Context.LongDoubleTy) == &llvm::APFloat::PPCDoubleDouble())) return false; } // Floating point conversions (C++ 4.8). SCS.Second = ICK_Floating_Conversion; FromType = ToType.getUnqualifiedType(); } else if ((FromType->isRealFloatingType() && ToType->isIntegralType(S.Context)) || (FromType->isIntegralOrUnscopedEnumerationType() && ToType->isRealFloatingType())) { // Conversions between bfloat and int are not permitted. if (FromType->isBFloat16Type() || ToType->isBFloat16Type()) return false; // Floating-integral conversions (C++ 4.9). SCS.Second = ICK_Floating_Integral; FromType = ToType.getUnqualifiedType(); } else if (S.IsBlockPointerConversion(FromType, ToType, FromType)) { SCS.Second = ICK_Block_Pointer_Conversion; } else if (AllowObjCWritebackConversion && S.isObjCWritebackConversion(FromType, ToType, FromType)) { SCS.Second = ICK_Writeback_Conversion; } else if (S.IsPointerConversion(From, FromType, ToType, InOverloadResolution, FromType, IncompatibleObjC)) { // Pointer conversions (C++ 4.10). SCS.Second = ICK_Pointer_Conversion; SCS.IncompatibleObjC = IncompatibleObjC; FromType = FromType.getUnqualifiedType(); } else if (S.IsMemberPointerConversion(From, FromType, ToType, InOverloadResolution, FromType)) { // Pointer to member conversions (4.11). SCS.Second = ICK_Pointer_Member; } else if (IsVectorConversion(S, FromType, ToType, SecondICK)) { SCS.Second = SecondICK; FromType = ToType.getUnqualifiedType(); } else if (!S.getLangOpts().CPlusPlus && S.Context.typesAreCompatible(ToType, FromType)) { // Compatible conversions (Clang extension for C function overloading) SCS.Second = ICK_Compatible_Conversion; FromType = ToType.getUnqualifiedType(); } else if (IsTransparentUnionStandardConversion(S, From, ToType, InOverloadResolution, SCS, CStyle)) { SCS.Second = ICK_TransparentUnionConversion; FromType = ToType; } else if (tryAtomicConversion(S, From, ToType, InOverloadResolution, SCS, CStyle)) { // tryAtomicConversion has updated the standard conversion sequence // appropriately. return true; } else if (ToType->isEventT() && From->isIntegerConstantExpr(S.getASTContext()) && From->EvaluateKnownConstInt(S.getASTContext()) == 0) { SCS.Second = ICK_Zero_Event_Conversion; FromType = ToType; } else if (ToType->isQueueT() && From->isIntegerConstantExpr(S.getASTContext()) && (From->EvaluateKnownConstInt(S.getASTContext()) == 0)) { SCS.Second = ICK_Zero_Queue_Conversion; FromType = ToType; } else if (ToType->isSamplerT() && From->isIntegerConstantExpr(S.getASTContext())) { SCS.Second = ICK_Compatible_Conversion; FromType = ToType; } else { // No second conversion required. SCS.Second = ICK_Identity; } SCS.setToType(1, FromType); // The third conversion can be a function pointer conversion or a // qualification conversion (C++ [conv.fctptr], [conv.qual]). bool ObjCLifetimeConversion; if (S.IsFunctionConversion(FromType, ToType, FromType)) { // Function pointer conversions (removing 'noexcept') including removal of // 'noreturn' (Clang extension). SCS.Third = ICK_Function_Conversion; } else if (S.IsQualificationConversion(FromType, ToType, CStyle, ObjCLifetimeConversion)) { SCS.Third = ICK_Qualification; SCS.QualificationIncludesObjCLifetime = ObjCLifetimeConversion; FromType = ToType; } else { // No conversion required SCS.Third = ICK_Identity; } // C++ [over.best.ics]p6: // [...] Any difference in top-level cv-qualification is // subsumed by the initialization itself and does not constitute // a conversion. [...] QualType CanonFrom = S.Context.getCanonicalType(FromType); QualType CanonTo = S.Context.getCanonicalType(ToType); if (CanonFrom.getLocalUnqualifiedType() == CanonTo.getLocalUnqualifiedType() && CanonFrom.getLocalQualifiers() != CanonTo.getLocalQualifiers()) { FromType = ToType; CanonFrom = CanonTo; } SCS.setToType(2, FromType); if (CanonFrom == CanonTo) return true; // If we have not converted the argument type to the parameter type, // this is a bad conversion sequence, unless we're resolving an overload in C. if (S.getLangOpts().CPlusPlus || !InOverloadResolution) return false; ExprResult ER = ExprResult{From}; Sema::AssignConvertType Conv = S.CheckSingleAssignmentConstraints(ToType, ER, /*Diagnose=*/false, /*DiagnoseCFAudited=*/false, /*ConvertRHS=*/false); ImplicitConversionKind SecondConv; switch (Conv) { case Sema::Compatible: SecondConv = ICK_C_Only_Conversion; break; // For our purposes, discarding qualifiers is just as bad as using an // incompatible pointer. Note that an IncompatiblePointer conversion can drop // qualifiers, as well. case Sema::CompatiblePointerDiscardsQualifiers: case Sema::IncompatiblePointer: case Sema::IncompatiblePointerSign: SecondConv = ICK_Incompatible_Pointer_Conversion; break; default: return false; } // First can only be an lvalue conversion, so we pretend that this was the // second conversion. First should already be valid from earlier in the // function. SCS.Second = SecondConv; SCS.setToType(1, ToType); // Third is Identity, because Second should rank us worse than any other // conversion. This could also be ICK_Qualification, but it's simpler to just // lump everything in with the second conversion, and we don't gain anything // from making this ICK_Qualification. SCS.Third = ICK_Identity; SCS.setToType(2, ToType); return true; } static bool IsTransparentUnionStandardConversion(Sema &S, Expr* From, QualType &ToType, bool InOverloadResolution, StandardConversionSequence &SCS, bool CStyle) { const RecordType *UT = ToType->getAsUnionType(); if (!UT || !UT->getDecl()->hasAttr()) return false; // The field to initialize within the transparent union. RecordDecl *UD = UT->getDecl(); // It's compatible if the expression matches any of the fields. for (const auto *it : UD->fields()) { if (IsStandardConversion(S, From, it->getType(), InOverloadResolution, SCS, CStyle, /*AllowObjCWritebackConversion=*/false)) { ToType = it->getType(); return true; } } return false; } /// IsIntegralPromotion - Determines whether the conversion from the /// expression From (whose potentially-adjusted type is FromType) to /// ToType is an integral promotion (C++ 4.5). If so, returns true and /// sets PromotedType to the promoted type. bool Sema::IsIntegralPromotion(Expr *From, QualType FromType, QualType ToType) { const BuiltinType *To = ToType->getAs(); // All integers are built-in. if (!To) { return false; } // An rvalue of type char, signed char, unsigned char, short int, or // unsigned short int can be converted to an rvalue of type int if // int can represent all the values of the source type; otherwise, // the source rvalue can be converted to an rvalue of type unsigned // int (C++ 4.5p1). if (FromType->isPromotableIntegerType() && !FromType->isBooleanType() && !FromType->isEnumeralType()) { if (// We can promote any signed, promotable integer type to an int (FromType->isSignedIntegerType() || // We can promote any unsigned integer type whose size is // less than int to an int. Context.getTypeSize(FromType) < Context.getTypeSize(ToType))) { return To->getKind() == BuiltinType::Int; } return To->getKind() == BuiltinType::UInt; } // C++11 [conv.prom]p3: // A prvalue of an unscoped enumeration type whose underlying type is not // fixed (7.2) can be converted to an rvalue a prvalue of the first of the // following types that can represent all the values of the enumeration // (i.e., the values in the range bmin to bmax as described in 7.2): int, // unsigned int, long int, unsigned long int, long long int, or unsigned // long long int. If none of the types in that list can represent all the // values of the enumeration, an rvalue a prvalue of an unscoped enumeration // type can be converted to an rvalue a prvalue of the extended integer type // with lowest integer conversion rank (4.13) greater than the rank of long // long in which all the values of the enumeration can be represented. If // there are two such extended types, the signed one is chosen. // C++11 [conv.prom]p4: // A prvalue of an unscoped enumeration type whose underlying type is fixed // can be converted to a prvalue of its underlying type. Moreover, if // integral promotion can be applied to its underlying type, a prvalue of an // unscoped enumeration type whose underlying type is fixed can also be // converted to a prvalue of the promoted underlying type. if (const EnumType *FromEnumType = FromType->getAs()) { // C++0x 7.2p9: Note that this implicit enum to int conversion is not // provided for a scoped enumeration. if (FromEnumType->getDecl()->isScoped()) return false; // We can perform an integral promotion to the underlying type of the enum, // even if that's not the promoted type. Note that the check for promoting // the underlying type is based on the type alone, and does not consider // the bitfield-ness of the actual source expression. if (FromEnumType->getDecl()->isFixed()) { QualType Underlying = FromEnumType->getDecl()->getIntegerType(); return Context.hasSameUnqualifiedType(Underlying, ToType) || IsIntegralPromotion(nullptr, Underlying, ToType); } // We have already pre-calculated the promotion type, so this is trivial. if (ToType->isIntegerType() && isCompleteType(From->getBeginLoc(), FromType)) return Context.hasSameUnqualifiedType( ToType, FromEnumType->getDecl()->getPromotionType()); // C++ [conv.prom]p5: // If the bit-field has an enumerated type, it is treated as any other // value of that type for promotion purposes. // // ... so do not fall through into the bit-field checks below in C++. if (getLangOpts().CPlusPlus) return false; } // C++0x [conv.prom]p2: // A prvalue of type char16_t, char32_t, or wchar_t (3.9.1) can be converted // to an rvalue a prvalue of the first of the following types that can // represent all the values of its underlying type: int, unsigned int, // long int, unsigned long int, long long int, or unsigned long long int. // If none of the types in that list can represent all the values of its // underlying type, an rvalue a prvalue of type char16_t, char32_t, // or wchar_t can be converted to an rvalue a prvalue of its underlying // type. if (FromType->isAnyCharacterType() && !FromType->isCharType() && ToType->isIntegerType()) { // Determine whether the type we're converting from is signed or // unsigned. bool FromIsSigned = FromType->isSignedIntegerType(); uint64_t FromSize = Context.getTypeSize(FromType); // The types we'll try to promote to, in the appropriate // order. Try each of these types. QualType PromoteTypes[6] = { Context.IntTy, Context.UnsignedIntTy, Context.LongTy, Context.UnsignedLongTy , Context.LongLongTy, Context.UnsignedLongLongTy }; for (int Idx = 0; Idx < 6; ++Idx) { uint64_t ToSize = Context.getTypeSize(PromoteTypes[Idx]); if (FromSize < ToSize || (FromSize == ToSize && FromIsSigned == PromoteTypes[Idx]->isSignedIntegerType())) { // We found the type that we can promote to. If this is the // type we wanted, we have a promotion. Otherwise, no // promotion. return Context.hasSameUnqualifiedType(ToType, PromoteTypes[Idx]); } } } // An rvalue for an integral bit-field (9.6) can be converted to an // rvalue of type int if int can represent all the values of the // bit-field; otherwise, it can be converted to unsigned int if // unsigned int can represent all the values of the bit-field. If // the bit-field is larger yet, no integral promotion applies to // it. If the bit-field has an enumerated type, it is treated as any // other value of that type for promotion purposes (C++ 4.5p3). // FIXME: We should delay checking of bit-fields until we actually perform the // conversion. // // FIXME: In C, only bit-fields of types _Bool, int, or unsigned int may be // promoted, per C11 6.3.1.1/2. We promote all bit-fields (including enum // bit-fields and those whose underlying type is larger than int) for GCC // compatibility. if (From) { if (FieldDecl *MemberDecl = From->getSourceBitField()) { Optional BitWidth; if (FromType->isIntegralType(Context) && (BitWidth = MemberDecl->getBitWidth()->getIntegerConstantExpr(Context))) { llvm::APSInt ToSize(BitWidth->getBitWidth(), BitWidth->isUnsigned()); ToSize = Context.getTypeSize(ToType); // Are we promoting to an int from a bitfield that fits in an int? if (*BitWidth < ToSize || (FromType->isSignedIntegerType() && *BitWidth <= ToSize)) { return To->getKind() == BuiltinType::Int; } // Are we promoting to an unsigned int from an unsigned bitfield // that fits into an unsigned int? if (FromType->isUnsignedIntegerType() && *BitWidth <= ToSize) { return To->getKind() == BuiltinType::UInt; } return false; } } } // An rvalue of type bool can be converted to an rvalue of type int, // with false becoming zero and true becoming one (C++ 4.5p4). if (FromType->isBooleanType() && To->getKind() == BuiltinType::Int) { return true; } return false; } /// IsFloatingPointPromotion - Determines whether the conversion from /// FromType to ToType is a floating point promotion (C++ 4.6). If so, /// returns true and sets PromotedType to the promoted type. bool Sema::IsFloatingPointPromotion(QualType FromType, QualType ToType) { if (const BuiltinType *FromBuiltin = FromType->getAs()) if (const BuiltinType *ToBuiltin = ToType->getAs()) { /// An rvalue of type float can be converted to an rvalue of type /// double. (C++ 4.6p1). if (FromBuiltin->getKind() == BuiltinType::Float && ToBuiltin->getKind() == BuiltinType::Double) return true; // C99 6.3.1.5p1: // When a float is promoted to double or long double, or a // double is promoted to long double [...]. if (!getLangOpts().CPlusPlus && (FromBuiltin->getKind() == BuiltinType::Float || FromBuiltin->getKind() == BuiltinType::Double) && (ToBuiltin->getKind() == BuiltinType::LongDouble || ToBuiltin->getKind() == BuiltinType::Float128)) return true; // Half can be promoted to float. if (!getLangOpts().NativeHalfType && FromBuiltin->getKind() == BuiltinType::Half && ToBuiltin->getKind() == BuiltinType::Float) return true; } return false; } /// Determine if a conversion is a complex promotion. /// /// A complex promotion is defined as a complex -> complex conversion /// where the conversion between the underlying real types is a /// floating-point or integral promotion. bool Sema::IsComplexPromotion(QualType FromType, QualType ToType) { const ComplexType *FromComplex = FromType->getAs(); if (!FromComplex) return false; const ComplexType *ToComplex = ToType->getAs(); if (!ToComplex) return false; return IsFloatingPointPromotion(FromComplex->getElementType(), ToComplex->getElementType()) || IsIntegralPromotion(nullptr, FromComplex->getElementType(), ToComplex->getElementType()); } /// BuildSimilarlyQualifiedPointerType - In a pointer conversion from /// the pointer type FromPtr to a pointer to type ToPointee, with the /// same type qualifiers as FromPtr has on its pointee type. ToType, /// if non-empty, will be a pointer to ToType that may or may not have /// the right set of qualifiers on its pointee. /// static QualType BuildSimilarlyQualifiedPointerType(const Type *FromPtr, QualType ToPointee, QualType ToType, ASTContext &Context, bool StripObjCLifetime = false) { assert((FromPtr->getTypeClass() == Type::Pointer || FromPtr->getTypeClass() == Type::ObjCObjectPointer) && "Invalid similarly-qualified pointer type"); /// Conversions to 'id' subsume cv-qualifier conversions. if (ToType->isObjCIdType() || ToType->isObjCQualifiedIdType()) return ToType.getUnqualifiedType(); QualType CanonFromPointee = Context.getCanonicalType(FromPtr->getPointeeType()); QualType CanonToPointee = Context.getCanonicalType(ToPointee); Qualifiers Quals = CanonFromPointee.getQualifiers(); if (StripObjCLifetime) Quals.removeObjCLifetime(); // Exact qualifier match -> return the pointer type we're converting to. if (CanonToPointee.getLocalQualifiers() == Quals) { // ToType is exactly what we need. Return it. if (!ToType.isNull()) return ToType.getUnqualifiedType(); // Build a pointer to ToPointee. It has the right qualifiers // already. if (isa(ToType)) return Context.getObjCObjectPointerType(ToPointee); return Context.getPointerType(ToPointee); } // Just build a canonical type that has the right qualifiers. QualType QualifiedCanonToPointee = Context.getQualifiedType(CanonToPointee.getLocalUnqualifiedType(), Quals); if (isa(ToType)) return Context.getObjCObjectPointerType(QualifiedCanonToPointee); return Context.getPointerType(QualifiedCanonToPointee); } static bool isNullPointerConstantForConversion(Expr *Expr, bool InOverloadResolution, ASTContext &Context) { // Handle value-dependent integral null pointer constants correctly. // http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#903 if (Expr->isValueDependent() && !Expr->isTypeDependent() && Expr->getType()->isIntegerType() && !Expr->getType()->isEnumeralType()) return !InOverloadResolution; return Expr->isNullPointerConstant(Context, InOverloadResolution? Expr::NPC_ValueDependentIsNotNull : Expr::NPC_ValueDependentIsNull); } /// IsPointerConversion - Determines whether the conversion of the /// expression From, which has the (possibly adjusted) type FromType, /// can be converted to the type ToType via a pointer conversion (C++ /// 4.10). If so, returns true and places the converted type (that /// might differ from ToType in its cv-qualifiers at some level) into /// ConvertedType. /// /// This routine also supports conversions to and from block pointers /// and conversions with Objective-C's 'id', 'id', and /// pointers to interfaces. FIXME: Once we've determined the /// appropriate overloading rules for Objective-C, we may want to /// split the Objective-C checks into a different routine; however, /// GCC seems to consider all of these conversions to be pointer /// conversions, so for now they live here. IncompatibleObjC will be /// set if the conversion is an allowed Objective-C conversion that /// should result in a warning. bool Sema::IsPointerConversion(Expr *From, QualType FromType, QualType ToType, bool InOverloadResolution, QualType& ConvertedType, bool &IncompatibleObjC) { IncompatibleObjC = false; if (isObjCPointerConversion(FromType, ToType, ConvertedType, IncompatibleObjC)) return true; // Conversion from a null pointer constant to any Objective-C pointer type. if (ToType->isObjCObjectPointerType() && isNullPointerConstantForConversion(From, InOverloadResolution, Context)) { ConvertedType = ToType; return true; } // Blocks: Block pointers can be converted to void*. if (FromType->isBlockPointerType() && ToType->isPointerType() && ToType->castAs()->getPointeeType()->isVoidType()) { ConvertedType = ToType; return true; } // Blocks: A null pointer constant can be converted to a block // pointer type. if (ToType->isBlockPointerType() && isNullPointerConstantForConversion(From, InOverloadResolution, Context)) { ConvertedType = ToType; return true; } // If the left-hand-side is nullptr_t, the right side can be a null // pointer constant. if (ToType->isNullPtrType() && isNullPointerConstantForConversion(From, InOverloadResolution, Context)) { ConvertedType = ToType; return true; } const PointerType* ToTypePtr = ToType->getAs(); if (!ToTypePtr) return false; // A null pointer constant can be converted to a pointer type (C++ 4.10p1). if (isNullPointerConstantForConversion(From, InOverloadResolution, Context)) { ConvertedType = ToType; return true; } // Beyond this point, both types need to be pointers // , including objective-c pointers. QualType ToPointeeType = ToTypePtr->getPointeeType(); if (FromType->isObjCObjectPointerType() && ToPointeeType->isVoidType() && !getLangOpts().ObjCAutoRefCount) { ConvertedType = BuildSimilarlyQualifiedPointerType( FromType->getAs(), ToPointeeType, ToType, Context); return true; } const PointerType *FromTypePtr = FromType->getAs(); if (!FromTypePtr) return false; QualType FromPointeeType = FromTypePtr->getPointeeType(); // If the unqualified pointee types are the same, this can't be a // pointer conversion, so don't do all of the work below. if (Context.hasSameUnqualifiedType(FromPointeeType, ToPointeeType)) return false; // An rvalue of type "pointer to cv T," where T is an object type, // can be converted to an rvalue of type "pointer to cv void" (C++ // 4.10p2). if (FromPointeeType->isIncompleteOrObjectType() && ToPointeeType->isVoidType()) { ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, ToPointeeType, ToType, Context, /*StripObjCLifetime=*/true); return true; } // MSVC allows implicit function to void* type conversion. if (getLangOpts().MSVCCompat && FromPointeeType->isFunctionType() && ToPointeeType->isVoidType()) { ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, ToPointeeType, ToType, Context); return true; } // When we're overloading in C, we allow a special kind of pointer // conversion for compatible-but-not-identical pointee types. if (!getLangOpts().CPlusPlus && Context.typesAreCompatible(FromPointeeType, ToPointeeType)) { ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, ToPointeeType, ToType, Context); return true; } // C++ [conv.ptr]p3: // // An rvalue of type "pointer to cv D," where D is a class type, // can be converted to an rvalue of type "pointer to cv B," where // B is a base class (clause 10) of D. If B is an inaccessible // (clause 11) or ambiguous (10.2) base class of D, a program that // necessitates this conversion is ill-formed. The result of the // conversion is a pointer to the base class sub-object of the // derived class object. The null pointer value is converted to // the null pointer value of the destination type. // // Note that we do not check for ambiguity or inaccessibility // here. That is handled by CheckPointerConversion. if (getLangOpts().CPlusPlus && FromPointeeType->isRecordType() && ToPointeeType->isRecordType() && !Context.hasSameUnqualifiedType(FromPointeeType, ToPointeeType) && IsDerivedFrom(From->getBeginLoc(), FromPointeeType, ToPointeeType)) { ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, ToPointeeType, ToType, Context); return true; } if (FromPointeeType->isVectorType() && ToPointeeType->isVectorType() && Context.areCompatibleVectorTypes(FromPointeeType, ToPointeeType)) { ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, ToPointeeType, ToType, Context); return true; } return false; } /// Adopt the given qualifiers for the given type. static QualType AdoptQualifiers(ASTContext &Context, QualType T, Qualifiers Qs){ Qualifiers TQs = T.getQualifiers(); // Check whether qualifiers already match. if (TQs == Qs) return T; if (Qs.compatiblyIncludes(TQs)) return Context.getQualifiedType(T, Qs); return Context.getQualifiedType(T.getUnqualifiedType(), Qs); } /// isObjCPointerConversion - Determines whether this is an /// Objective-C pointer conversion. Subroutine of IsPointerConversion, /// with the same arguments and return values. bool Sema::isObjCPointerConversion(QualType FromType, QualType ToType, QualType& ConvertedType, bool &IncompatibleObjC) { if (!getLangOpts().ObjC) return false; // The set of qualifiers on the type we're converting from. Qualifiers FromQualifiers = FromType.getQualifiers(); // First, we handle all conversions on ObjC object pointer types. const ObjCObjectPointerType* ToObjCPtr = ToType->getAs(); const ObjCObjectPointerType *FromObjCPtr = FromType->getAs(); if (ToObjCPtr && FromObjCPtr) { // If the pointee types are the same (ignoring qualifications), // then this is not a pointer conversion. if (Context.hasSameUnqualifiedType(ToObjCPtr->getPointeeType(), FromObjCPtr->getPointeeType())) return false; // Conversion between Objective-C pointers. if (Context.canAssignObjCInterfaces(ToObjCPtr, FromObjCPtr)) { const ObjCInterfaceType* LHS = ToObjCPtr->getInterfaceType(); const ObjCInterfaceType* RHS = FromObjCPtr->getInterfaceType(); if (getLangOpts().CPlusPlus && LHS && RHS && !ToObjCPtr->getPointeeType().isAtLeastAsQualifiedAs( FromObjCPtr->getPointeeType())) return false; ConvertedType = BuildSimilarlyQualifiedPointerType(FromObjCPtr, ToObjCPtr->getPointeeType(), ToType, Context); ConvertedType = AdoptQualifiers(Context, ConvertedType, FromQualifiers); return true; } if (Context.canAssignObjCInterfaces(FromObjCPtr, ToObjCPtr)) { // Okay: this is some kind of implicit downcast of Objective-C // interfaces, which is permitted. However, we're going to // complain about it. IncompatibleObjC = true; ConvertedType = BuildSimilarlyQualifiedPointerType(FromObjCPtr, ToObjCPtr->getPointeeType(), ToType, Context); ConvertedType = AdoptQualifiers(Context, ConvertedType, FromQualifiers); return true; } } // Beyond this point, both types need to be C pointers or block pointers. QualType ToPointeeType; if (const PointerType *ToCPtr = ToType->getAs()) ToPointeeType = ToCPtr->getPointeeType(); else if (const BlockPointerType *ToBlockPtr = ToType->getAs()) { // Objective C++: We're able to convert from a pointer to any object // to a block pointer type. if (FromObjCPtr && FromObjCPtr->isObjCBuiltinType()) { ConvertedType = AdoptQualifiers(Context, ToType, FromQualifiers); return true; } ToPointeeType = ToBlockPtr->getPointeeType(); } else if (FromType->getAs() && ToObjCPtr && ToObjCPtr->isObjCBuiltinType()) { // Objective C++: We're able to convert from a block pointer type to a // pointer to any object. ConvertedType = AdoptQualifiers(Context, ToType, FromQualifiers); return true; } else return false; QualType FromPointeeType; if (const PointerType *FromCPtr = FromType->getAs()) FromPointeeType = FromCPtr->getPointeeType(); else if (const BlockPointerType *FromBlockPtr = FromType->getAs()) FromPointeeType = FromBlockPtr->getPointeeType(); else return false; // If we have pointers to pointers, recursively check whether this // is an Objective-C conversion. if (FromPointeeType->isPointerType() && ToPointeeType->isPointerType() && isObjCPointerConversion(FromPointeeType, ToPointeeType, ConvertedType, IncompatibleObjC)) { // We always complain about this conversion. IncompatibleObjC = true; ConvertedType = Context.getPointerType(ConvertedType); ConvertedType = AdoptQualifiers(Context, ConvertedType, FromQualifiers); return true; } // Allow conversion of pointee being objective-c pointer to another one; // as in I* to id. if (FromPointeeType->getAs() && ToPointeeType->getAs() && isObjCPointerConversion(FromPointeeType, ToPointeeType, ConvertedType, IncompatibleObjC)) { ConvertedType = Context.getPointerType(ConvertedType); ConvertedType = AdoptQualifiers(Context, ConvertedType, FromQualifiers); return true; } // If we have pointers to functions or blocks, check whether the only // differences in the argument and result types are in Objective-C // pointer conversions. If so, we permit the conversion (but // complain about it). const FunctionProtoType *FromFunctionType = FromPointeeType->getAs(); const FunctionProtoType *ToFunctionType = ToPointeeType->getAs(); if (FromFunctionType && ToFunctionType) { // If the function types are exactly the same, this isn't an // Objective-C pointer conversion. if (Context.getCanonicalType(FromPointeeType) == Context.getCanonicalType(ToPointeeType)) return false; // Perform the quick checks that will tell us whether these // function types are obviously different. if (FromFunctionType->getNumParams() != ToFunctionType->getNumParams() || FromFunctionType->isVariadic() != ToFunctionType->isVariadic() || FromFunctionType->getMethodQuals() != ToFunctionType->getMethodQuals()) return false; bool HasObjCConversion = false; if (Context.getCanonicalType(FromFunctionType->getReturnType()) == Context.getCanonicalType(ToFunctionType->getReturnType())) { // Okay, the types match exactly. Nothing to do. } else if (isObjCPointerConversion(FromFunctionType->getReturnType(), ToFunctionType->getReturnType(), ConvertedType, IncompatibleObjC)) { // Okay, we have an Objective-C pointer conversion. HasObjCConversion = true; } else { // Function types are too different. Abort. return false; } // Check argument types. for (unsigned ArgIdx = 0, NumArgs = FromFunctionType->getNumParams(); ArgIdx != NumArgs; ++ArgIdx) { QualType FromArgType = FromFunctionType->getParamType(ArgIdx); QualType ToArgType = ToFunctionType->getParamType(ArgIdx); if (Context.getCanonicalType(FromArgType) == Context.getCanonicalType(ToArgType)) { // Okay, the types match exactly. Nothing to do. } else if (isObjCPointerConversion(FromArgType, ToArgType, ConvertedType, IncompatibleObjC)) { // Okay, we have an Objective-C pointer conversion. HasObjCConversion = true; } else { // Argument types are too different. Abort. return false; } } if (HasObjCConversion) { // We had an Objective-C conversion. Allow this pointer // conversion, but complain about it. ConvertedType = AdoptQualifiers(Context, ToType, FromQualifiers); IncompatibleObjC = true; return true; } } return false; } /// Determine whether this is an Objective-C writeback conversion, /// used for parameter passing when performing automatic reference counting. /// /// \param FromType The type we're converting form. /// /// \param ToType The type we're converting to. /// /// \param ConvertedType The type that will be produced after applying /// this conversion. bool Sema::isObjCWritebackConversion(QualType FromType, QualType ToType, QualType &ConvertedType) { if (!getLangOpts().ObjCAutoRefCount || Context.hasSameUnqualifiedType(FromType, ToType)) return false; // Parameter must be a pointer to __autoreleasing (with no other qualifiers). QualType ToPointee; if (const PointerType *ToPointer = ToType->getAs()) ToPointee = ToPointer->getPointeeType(); else return false; Qualifiers ToQuals = ToPointee.getQualifiers(); if (!ToPointee->isObjCLifetimeType() || ToQuals.getObjCLifetime() != Qualifiers::OCL_Autoreleasing || !ToQuals.withoutObjCLifetime().empty()) return false; // Argument must be a pointer to __strong to __weak. QualType FromPointee; if (const PointerType *FromPointer = FromType->getAs()) FromPointee = FromPointer->getPointeeType(); else return false; Qualifiers FromQuals = FromPointee.getQualifiers(); if (!FromPointee->isObjCLifetimeType() || (FromQuals.getObjCLifetime() != Qualifiers::OCL_Strong && FromQuals.getObjCLifetime() != Qualifiers::OCL_Weak)) return false; // Make sure that we have compatible qualifiers. FromQuals.setObjCLifetime(Qualifiers::OCL_Autoreleasing); if (!ToQuals.compatiblyIncludes(FromQuals)) return false; // Remove qualifiers from the pointee type we're converting from; they // aren't used in the compatibility check belong, and we'll be adding back // qualifiers (with __autoreleasing) if the compatibility check succeeds. FromPointee = FromPointee.getUnqualifiedType(); // The unqualified form of the pointee types must be compatible. ToPointee = ToPointee.getUnqualifiedType(); bool IncompatibleObjC; if (Context.typesAreCompatible(FromPointee, ToPointee)) FromPointee = ToPointee; else if (!isObjCPointerConversion(FromPointee, ToPointee, FromPointee, IncompatibleObjC)) return false; /// Construct the type we're converting to, which is a pointer to /// __autoreleasing pointee. FromPointee = Context.getQualifiedType(FromPointee, FromQuals); ConvertedType = Context.getPointerType(FromPointee); return true; } bool Sema::IsBlockPointerConversion(QualType FromType, QualType ToType, QualType& ConvertedType) { QualType ToPointeeType; if (const BlockPointerType *ToBlockPtr = ToType->getAs()) ToPointeeType = ToBlockPtr->getPointeeType(); else return false; QualType FromPointeeType; if (const BlockPointerType *FromBlockPtr = FromType->getAs()) FromPointeeType = FromBlockPtr->getPointeeType(); else return false; // We have pointer to blocks, check whether the only // differences in the argument and result types are in Objective-C // pointer conversions. If so, we permit the conversion. const FunctionProtoType *FromFunctionType = FromPointeeType->getAs(); const FunctionProtoType *ToFunctionType = ToPointeeType->getAs(); if (!FromFunctionType || !ToFunctionType) return false; if (Context.hasSameType(FromPointeeType, ToPointeeType)) return true; // Perform the quick checks that will tell us whether these // function types are obviously different. if (FromFunctionType->getNumParams() != ToFunctionType->getNumParams() || FromFunctionType->isVariadic() != ToFunctionType->isVariadic()) return false; FunctionType::ExtInfo FromEInfo = FromFunctionType->getExtInfo(); FunctionType::ExtInfo ToEInfo = ToFunctionType->getExtInfo(); if (FromEInfo != ToEInfo) return false; bool IncompatibleObjC = false; if (Context.hasSameType(FromFunctionType->getReturnType(), ToFunctionType->getReturnType())) { // Okay, the types match exactly. Nothing to do. } else { QualType RHS = FromFunctionType->getReturnType(); QualType LHS = ToFunctionType->getReturnType(); if ((!getLangOpts().CPlusPlus || !RHS->isRecordType()) && !RHS.hasQualifiers() && LHS.hasQualifiers()) LHS = LHS.getUnqualifiedType(); if (Context.hasSameType(RHS,LHS)) { // OK exact match. } else if (isObjCPointerConversion(RHS, LHS, ConvertedType, IncompatibleObjC)) { if (IncompatibleObjC) return false; // Okay, we have an Objective-C pointer conversion. } else return false; } // Check argument types. for (unsigned ArgIdx = 0, NumArgs = FromFunctionType->getNumParams(); ArgIdx != NumArgs; ++ArgIdx) { IncompatibleObjC = false; QualType FromArgType = FromFunctionType->getParamType(ArgIdx); QualType ToArgType = ToFunctionType->getParamType(ArgIdx); if (Context.hasSameType(FromArgType, ToArgType)) { // Okay, the types match exactly. Nothing to do. } else if (isObjCPointerConversion(ToArgType, FromArgType, ConvertedType, IncompatibleObjC)) { if (IncompatibleObjC) return false; // Okay, we have an Objective-C pointer conversion. } else // Argument types are too different. Abort. return false; } SmallVector NewParamInfos; bool CanUseToFPT, CanUseFromFPT; if (!Context.mergeExtParameterInfo(ToFunctionType, FromFunctionType, CanUseToFPT, CanUseFromFPT, NewParamInfos)) return false; ConvertedType = ToType; return true; } enum { ft_default, ft_different_class, ft_parameter_arity, ft_parameter_mismatch, ft_return_type, ft_qualifer_mismatch, ft_noexcept }; /// Attempts to get the FunctionProtoType from a Type. Handles /// MemberFunctionPointers properly. static const FunctionProtoType *tryGetFunctionProtoType(QualType FromType) { if (auto *FPT = FromType->getAs()) return FPT; if (auto *MPT = FromType->getAs()) return MPT->getPointeeType()->getAs(); return nullptr; } /// HandleFunctionTypeMismatch - Gives diagnostic information for differeing /// function types. Catches different number of parameter, mismatch in /// parameter types, and different return types. void Sema::HandleFunctionTypeMismatch(PartialDiagnostic &PDiag, QualType FromType, QualType ToType) { // If either type is not valid, include no extra info. if (FromType.isNull() || ToType.isNull()) { PDiag << ft_default; return; } // Get the function type from the pointers. if (FromType->isMemberPointerType() && ToType->isMemberPointerType()) { const auto *FromMember = FromType->castAs(), *ToMember = ToType->castAs(); if (!Context.hasSameType(FromMember->getClass(), ToMember->getClass())) { PDiag << ft_different_class << QualType(ToMember->getClass(), 0) << QualType(FromMember->getClass(), 0); return; } FromType = FromMember->getPointeeType(); ToType = ToMember->getPointeeType(); } if (FromType->isPointerType()) FromType = FromType->getPointeeType(); if (ToType->isPointerType()) ToType = ToType->getPointeeType(); // Remove references. FromType = FromType.getNonReferenceType(); ToType = ToType.getNonReferenceType(); // Don't print extra info for non-specialized template functions. if (FromType->isInstantiationDependentType() && !FromType->getAs()) { PDiag << ft_default; return; } // No extra info for same types. if (Context.hasSameType(FromType, ToType)) { PDiag << ft_default; return; } const FunctionProtoType *FromFunction = tryGetFunctionProtoType(FromType), *ToFunction = tryGetFunctionProtoType(ToType); // Both types need to be function types. if (!FromFunction || !ToFunction) { PDiag << ft_default; return; } if (FromFunction->getNumParams() != ToFunction->getNumParams()) { PDiag << ft_parameter_arity << ToFunction->getNumParams() << FromFunction->getNumParams(); return; } // Handle different parameter types. unsigned ArgPos; if (!FunctionParamTypesAreEqual(FromFunction, ToFunction, &ArgPos)) { PDiag << ft_parameter_mismatch << ArgPos + 1 << ToFunction->getParamType(ArgPos) << FromFunction->getParamType(ArgPos); return; } // Handle different return type. if (!Context.hasSameType(FromFunction->getReturnType(), ToFunction->getReturnType())) { PDiag << ft_return_type << ToFunction->getReturnType() << FromFunction->getReturnType(); return; } if (FromFunction->getMethodQuals() != ToFunction->getMethodQuals()) { PDiag << ft_qualifer_mismatch << ToFunction->getMethodQuals() << FromFunction->getMethodQuals(); return; } // Handle exception specification differences on canonical type (in C++17 // onwards). if (cast(FromFunction->getCanonicalTypeUnqualified()) ->isNothrow() != cast(ToFunction->getCanonicalTypeUnqualified()) ->isNothrow()) { PDiag << ft_noexcept; return; } // Unable to find a difference, so add no extra info. PDiag << ft_default; } /// FunctionParamTypesAreEqual - This routine checks two function proto types /// for equality of their argument types. Caller has already checked that /// they have same number of arguments. If the parameters are different, /// ArgPos will have the parameter index of the first different parameter. bool Sema::FunctionParamTypesAreEqual(const FunctionProtoType *OldType, const FunctionProtoType *NewType, unsigned *ArgPos) { for (FunctionProtoType::param_type_iterator O = OldType->param_type_begin(), N = NewType->param_type_begin(), E = OldType->param_type_end(); O && (O != E); ++O, ++N) { // Ignore address spaces in pointee type. This is to disallow overloading // on __ptr32/__ptr64 address spaces. QualType Old = Context.removePtrSizeAddrSpace(O->getUnqualifiedType()); QualType New = Context.removePtrSizeAddrSpace(N->getUnqualifiedType()); if (!Context.hasSameType(Old, New)) { if (ArgPos) *ArgPos = O - OldType->param_type_begin(); return false; } } return true; } /// CheckPointerConversion - Check the pointer conversion from the /// expression From to the type ToType. This routine checks for /// ambiguous or inaccessible derived-to-base pointer /// conversions for which IsPointerConversion has already returned /// true. It returns true and produces a diagnostic if there was an /// error, or returns false otherwise. bool Sema::CheckPointerConversion(Expr *From, QualType ToType, CastKind &Kind, CXXCastPath& BasePath, bool IgnoreBaseAccess, bool Diagnose) { QualType FromType = From->getType(); bool IsCStyleOrFunctionalCast = IgnoreBaseAccess; Kind = CK_BitCast; if (Diagnose && !IsCStyleOrFunctionalCast && !FromType->isAnyPointerType() && From->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNotNull) == Expr::NPCK_ZeroExpression) { if (Context.hasSameUnqualifiedType(From->getType(), Context.BoolTy)) DiagRuntimeBehavior(From->getExprLoc(), From, PDiag(diag::warn_impcast_bool_to_null_pointer) << ToType << From->getSourceRange()); else if (!isUnevaluatedContext()) Diag(From->getExprLoc(), diag::warn_non_literal_null_pointer) << ToType << From->getSourceRange(); } if (const PointerType *ToPtrType = ToType->getAs()) { if (const PointerType *FromPtrType = FromType->getAs()) { QualType FromPointeeType = FromPtrType->getPointeeType(), ToPointeeType = ToPtrType->getPointeeType(); if (FromPointeeType->isRecordType() && ToPointeeType->isRecordType() && !Context.hasSameUnqualifiedType(FromPointeeType, ToPointeeType)) { // We must have a derived-to-base conversion. Check an // ambiguous or inaccessible conversion. unsigned InaccessibleID = 0; unsigned AmbiguousID = 0; if (Diagnose) { InaccessibleID = diag::err_upcast_to_inaccessible_base; AmbiguousID = diag::err_ambiguous_derived_to_base_conv; } if (CheckDerivedToBaseConversion( FromPointeeType, ToPointeeType, InaccessibleID, AmbiguousID, From->getExprLoc(), From->getSourceRange(), DeclarationName(), &BasePath, IgnoreBaseAccess)) return true; // The conversion was successful. Kind = CK_DerivedToBase; } if (Diagnose && !IsCStyleOrFunctionalCast && FromPointeeType->isFunctionType() && ToPointeeType->isVoidType()) { assert(getLangOpts().MSVCCompat && "this should only be possible with MSVCCompat!"); Diag(From->getExprLoc(), diag::ext_ms_impcast_fn_obj) << From->getSourceRange(); } } } else if (const ObjCObjectPointerType *ToPtrType = ToType->getAs()) { if (const ObjCObjectPointerType *FromPtrType = FromType->getAs()) { // Objective-C++ conversions are always okay. // FIXME: We should have a different class of conversions for the // Objective-C++ implicit conversions. if (FromPtrType->isObjCBuiltinType() || ToPtrType->isObjCBuiltinType()) return false; } else if (FromType->isBlockPointerType()) { Kind = CK_BlockPointerToObjCPointerCast; } else { Kind = CK_CPointerToObjCPointerCast; } } else if (ToType->isBlockPointerType()) { if (!FromType->isBlockPointerType()) Kind = CK_AnyPointerToBlockPointerCast; } // We shouldn't fall into this case unless it's valid for other // reasons. if (From->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNull)) Kind = CK_NullToPointer; return false; } /// IsMemberPointerConversion - Determines whether the conversion of the /// expression From, which has the (possibly adjusted) type FromType, can be /// converted to the type ToType via a member pointer conversion (C++ 4.11). /// If so, returns true and places the converted type (that might differ from /// ToType in its cv-qualifiers at some level) into ConvertedType. bool Sema::IsMemberPointerConversion(Expr *From, QualType FromType, QualType ToType, bool InOverloadResolution, QualType &ConvertedType) { const MemberPointerType *ToTypePtr = ToType->getAs(); if (!ToTypePtr) return false; // A null pointer constant can be converted to a member pointer (C++ 4.11p1) if (From->isNullPointerConstant(Context, InOverloadResolution? Expr::NPC_ValueDependentIsNotNull : Expr::NPC_ValueDependentIsNull)) { ConvertedType = ToType; return true; } // Otherwise, both types have to be member pointers. const MemberPointerType *FromTypePtr = FromType->getAs(); if (!FromTypePtr) return false; // A pointer to member of B can be converted to a pointer to member of D, // where D is derived from B (C++ 4.11p2). QualType FromClass(FromTypePtr->getClass(), 0); QualType ToClass(ToTypePtr->getClass(), 0); if (!Context.hasSameUnqualifiedType(FromClass, ToClass) && IsDerivedFrom(From->getBeginLoc(), ToClass, FromClass)) { ConvertedType = Context.getMemberPointerType(FromTypePtr->getPointeeType(), ToClass.getTypePtr()); return true; } return false; } /// CheckMemberPointerConversion - Check the member pointer conversion from the /// expression From to the type ToType. This routine checks for ambiguous or /// virtual or inaccessible base-to-derived member pointer conversions /// for which IsMemberPointerConversion has already returned true. It returns /// true and produces a diagnostic if there was an error, or returns false /// otherwise. bool Sema::CheckMemberPointerConversion(Expr *From, QualType ToType, CastKind &Kind, CXXCastPath &BasePath, bool IgnoreBaseAccess) { QualType FromType = From->getType(); const MemberPointerType *FromPtrType = FromType->getAs(); if (!FromPtrType) { // This must be a null pointer to member pointer conversion assert(From->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNull) && "Expr must be null pointer constant!"); Kind = CK_NullToMemberPointer; return false; } const MemberPointerType *ToPtrType = ToType->getAs(); assert(ToPtrType && "No member pointer cast has a target type " "that is not a member pointer."); QualType FromClass = QualType(FromPtrType->getClass(), 0); QualType ToClass = QualType(ToPtrType->getClass(), 0); // FIXME: What about dependent types? assert(FromClass->isRecordType() && "Pointer into non-class."); assert(ToClass->isRecordType() && "Pointer into non-class."); CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true, /*DetectVirtual=*/true); bool DerivationOkay = IsDerivedFrom(From->getBeginLoc(), ToClass, FromClass, Paths); assert(DerivationOkay && "Should not have been called if derivation isn't OK."); (void)DerivationOkay; if (Paths.isAmbiguous(Context.getCanonicalType(FromClass). getUnqualifiedType())) { std::string PathDisplayStr = getAmbiguousPathsDisplayString(Paths); Diag(From->getExprLoc(), diag::err_ambiguous_memptr_conv) << 0 << FromClass << ToClass << PathDisplayStr << From->getSourceRange(); return true; } if (const RecordType *VBase = Paths.getDetectedVirtual()) { Diag(From->getExprLoc(), diag::err_memptr_conv_via_virtual) << FromClass << ToClass << QualType(VBase, 0) << From->getSourceRange(); return true; } if (!IgnoreBaseAccess) CheckBaseClassAccess(From->getExprLoc(), FromClass, ToClass, Paths.front(), diag::err_downcast_from_inaccessible_base); // Must be a base to derived member conversion. BuildBasePathArray(Paths, BasePath); Kind = CK_BaseToDerivedMemberPointer; return false; } /// Determine whether the lifetime conversion between the two given /// qualifiers sets is nontrivial. static bool isNonTrivialObjCLifetimeConversion(Qualifiers FromQuals, Qualifiers ToQuals) { // Converting anything to const __unsafe_unretained is trivial. if (ToQuals.hasConst() && ToQuals.getObjCLifetime() == Qualifiers::OCL_ExplicitNone) return false; return true; } /// Perform a single iteration of the loop for checking if a qualification /// conversion is valid. /// /// Specifically, check whether any change between the qualifiers of \p /// FromType and \p ToType is permissible, given knowledge about whether every /// outer layer is const-qualified. static bool isQualificationConversionStep(QualType FromType, QualType ToType, bool CStyle, bool IsTopLevel, bool &PreviousToQualsIncludeConst, bool &ObjCLifetimeConversion) { Qualifiers FromQuals = FromType.getQualifiers(); Qualifiers ToQuals = ToType.getQualifiers(); // Ignore __unaligned qualifier if this type is void. if (ToType.getUnqualifiedType()->isVoidType()) FromQuals.removeUnaligned(); // Objective-C ARC: // Check Objective-C lifetime conversions. if (FromQuals.getObjCLifetime() != ToQuals.getObjCLifetime()) { if (ToQuals.compatiblyIncludesObjCLifetime(FromQuals)) { if (isNonTrivialObjCLifetimeConversion(FromQuals, ToQuals)) ObjCLifetimeConversion = true; FromQuals.removeObjCLifetime(); ToQuals.removeObjCLifetime(); } else { // Qualification conversions cannot cast between different // Objective-C lifetime qualifiers. return false; } } // Allow addition/removal of GC attributes but not changing GC attributes. if (FromQuals.getObjCGCAttr() != ToQuals.getObjCGCAttr() && (!FromQuals.hasObjCGCAttr() || !ToQuals.hasObjCGCAttr())) { FromQuals.removeObjCGCAttr(); ToQuals.removeObjCGCAttr(); } // -- for every j > 0, if const is in cv 1,j then const is in cv // 2,j, and similarly for volatile. if (!CStyle && !ToQuals.compatiblyIncludes(FromQuals)) return false; // If address spaces mismatch: // - in top level it is only valid to convert to addr space that is a // superset in all cases apart from C-style casts where we allow // conversions between overlapping address spaces. // - in non-top levels it is not a valid conversion. if (ToQuals.getAddressSpace() != FromQuals.getAddressSpace() && (!IsTopLevel || !(ToQuals.isAddressSpaceSupersetOf(FromQuals) || (CStyle && FromQuals.isAddressSpaceSupersetOf(ToQuals))))) return false; // -- if the cv 1,j and cv 2,j are different, then const is in // every cv for 0 < k < j. if (!CStyle && FromQuals.getCVRQualifiers() != ToQuals.getCVRQualifiers() && !PreviousToQualsIncludeConst) return false; // Keep track of whether all prior cv-qualifiers in the "to" type // include const. PreviousToQualsIncludeConst = PreviousToQualsIncludeConst && ToQuals.hasConst(); return true; } /// IsQualificationConversion - Determines whether the conversion from /// an rvalue of type FromType to ToType is a qualification conversion /// (C++ 4.4). /// /// \param ObjCLifetimeConversion Output parameter that will be set to indicate /// when the qualification conversion involves a change in the Objective-C /// object lifetime. bool Sema::IsQualificationConversion(QualType FromType, QualType ToType, bool CStyle, bool &ObjCLifetimeConversion) { FromType = Context.getCanonicalType(FromType); ToType = Context.getCanonicalType(ToType); ObjCLifetimeConversion = false; // If FromType and ToType are the same type, this is not a // qualification conversion. if (FromType.getUnqualifiedType() == ToType.getUnqualifiedType()) return false; // (C++ 4.4p4): // A conversion can add cv-qualifiers at levels other than the first // in multi-level pointers, subject to the following rules: [...] bool PreviousToQualsIncludeConst = true; bool UnwrappedAnyPointer = false; while (Context.UnwrapSimilarTypes(FromType, ToType)) { if (!isQualificationConversionStep( FromType, ToType, CStyle, !UnwrappedAnyPointer, PreviousToQualsIncludeConst, ObjCLifetimeConversion)) return false; UnwrappedAnyPointer = true; } // We are left with FromType and ToType being the pointee types // after unwrapping the original FromType and ToType the same number // of times. If we unwrapped any pointers, and if FromType and // ToType have the same unqualified type (since we checked // qualifiers above), then this is a qualification conversion. return UnwrappedAnyPointer && Context.hasSameUnqualifiedType(FromType,ToType); } /// - Determine whether this is a conversion from a scalar type to an /// atomic type. /// /// If successful, updates \c SCS's second and third steps in the conversion /// sequence to finish the conversion. static bool tryAtomicConversion(Sema &S, Expr *From, QualType ToType, bool InOverloadResolution, StandardConversionSequence &SCS, bool CStyle) { const AtomicType *ToAtomic = ToType->getAs(); if (!ToAtomic) return false; StandardConversionSequence InnerSCS; if (!IsStandardConversion(S, From, ToAtomic->getValueType(), InOverloadResolution, InnerSCS, CStyle, /*AllowObjCWritebackConversion=*/false)) return false; SCS.Second = InnerSCS.Second; SCS.setToType(1, InnerSCS.getToType(1)); SCS.Third = InnerSCS.Third; SCS.QualificationIncludesObjCLifetime = InnerSCS.QualificationIncludesObjCLifetime; SCS.setToType(2, InnerSCS.getToType(2)); return true; } static bool isFirstArgumentCompatibleWithType(ASTContext &Context, CXXConstructorDecl *Constructor, QualType Type) { const auto *CtorType = Constructor->getType()->castAs(); if (CtorType->getNumParams() > 0) { QualType FirstArg = CtorType->getParamType(0); if (Context.hasSameUnqualifiedType(Type, FirstArg.getNonReferenceType())) return true; } return false; } static OverloadingResult IsInitializerListConstructorConversion(Sema &S, Expr *From, QualType ToType, CXXRecordDecl *To, UserDefinedConversionSequence &User, OverloadCandidateSet &CandidateSet, bool AllowExplicit) { CandidateSet.clear(OverloadCandidateSet::CSK_InitByUserDefinedConversion); for (auto *D : S.LookupConstructors(To)) { auto Info = getConstructorInfo(D); if (!Info) continue; bool Usable = !Info.Constructor->isInvalidDecl() && S.isInitListConstructor(Info.Constructor); if (Usable) { bool SuppressUserConversions = false; if (Info.ConstructorTmpl) S.AddTemplateOverloadCandidate(Info.ConstructorTmpl, Info.FoundDecl, /*ExplicitArgs*/ nullptr, From, CandidateSet, SuppressUserConversions, /*PartialOverloading*/ false, AllowExplicit); else S.AddOverloadCandidate(Info.Constructor, Info.FoundDecl, From, CandidateSet, SuppressUserConversions, /*PartialOverloading*/ false, AllowExplicit); } } bool HadMultipleCandidates = (CandidateSet.size() > 1); OverloadCandidateSet::iterator Best; switch (auto Result = CandidateSet.BestViableFunction(S, From->getBeginLoc(), Best)) { case OR_Deleted: case OR_Success: { // Record the standard conversion we used and the conversion function. CXXConstructorDecl *Constructor = cast(Best->Function); QualType ThisType = Constructor->getThisType(); // Initializer lists don't have conversions as such. User.Before.setAsIdentityConversion(); User.HadMultipleCandidates = HadMultipleCandidates; User.ConversionFunction = Constructor; User.FoundConversionFunction = Best->FoundDecl; User.After.setAsIdentityConversion(); User.After.setFromType(ThisType->castAs()->getPointeeType()); User.After.setAllToTypes(ToType); return Result; } case OR_No_Viable_Function: return OR_No_Viable_Function; case OR_Ambiguous: return OR_Ambiguous; } llvm_unreachable("Invalid OverloadResult!"); } /// Determines whether there is a user-defined conversion sequence /// (C++ [over.ics.user]) that converts expression From to the type /// ToType. If such a conversion exists, User will contain the /// user-defined conversion sequence that performs such a conversion /// and this routine will return true. Otherwise, this routine returns /// false and User is unspecified. /// /// \param AllowExplicit true if the conversion should consider C++0x /// "explicit" conversion functions as well as non-explicit conversion /// functions (C++0x [class.conv.fct]p2). /// /// \param AllowObjCConversionOnExplicit true if the conversion should /// allow an extra Objective-C pointer conversion on uses of explicit /// constructors. Requires \c AllowExplicit to also be set. static OverloadingResult IsUserDefinedConversion(Sema &S, Expr *From, QualType ToType, UserDefinedConversionSequence &User, OverloadCandidateSet &CandidateSet, AllowedExplicit AllowExplicit, bool AllowObjCConversionOnExplicit) { assert(AllowExplicit != AllowedExplicit::None || !AllowObjCConversionOnExplicit); CandidateSet.clear(OverloadCandidateSet::CSK_InitByUserDefinedConversion); // Whether we will only visit constructors. bool ConstructorsOnly = false; // If the type we are conversion to is a class type, enumerate its // constructors. if (const RecordType *ToRecordType = ToType->getAs()) { // C++ [over.match.ctor]p1: // When objects of class type are direct-initialized (8.5), or // copy-initialized from an expression of the same or a // derived class type (8.5), overload resolution selects the // constructor. [...] For copy-initialization, the candidate // functions are all the converting constructors (12.3.1) of // that class. The argument list is the expression-list within // the parentheses of the initializer. if (S.Context.hasSameUnqualifiedType(ToType, From->getType()) || (From->getType()->getAs() && S.IsDerivedFrom(From->getBeginLoc(), From->getType(), ToType))) ConstructorsOnly = true; if (!S.isCompleteType(From->getExprLoc(), ToType)) { // We're not going to find any constructors. } else if (CXXRecordDecl *ToRecordDecl = dyn_cast(ToRecordType->getDecl())) { Expr **Args = &From; unsigned NumArgs = 1; bool ListInitializing = false; if (InitListExpr *InitList = dyn_cast(From)) { // But first, see if there is an init-list-constructor that will work. OverloadingResult Result = IsInitializerListConstructorConversion( S, From, ToType, ToRecordDecl, User, CandidateSet, AllowExplicit == AllowedExplicit::All); if (Result != OR_No_Viable_Function) return Result; // Never mind. CandidateSet.clear( OverloadCandidateSet::CSK_InitByUserDefinedConversion); // If we're list-initializing, we pass the individual elements as // arguments, not the entire list. Args = InitList->getInits(); NumArgs = InitList->getNumInits(); ListInitializing = true; } for (auto *D : S.LookupConstructors(ToRecordDecl)) { auto Info = getConstructorInfo(D); if (!Info) continue; bool Usable = !Info.Constructor->isInvalidDecl(); if (!ListInitializing) Usable = Usable && Info.Constructor->isConvertingConstructor( /*AllowExplicit*/ true); if (Usable) { bool SuppressUserConversions = !ConstructorsOnly; // C++20 [over.best.ics.general]/4.5: // if the target is the first parameter of a constructor [of class // X] and the constructor [...] is a candidate by [...] the second // phase of [over.match.list] when the initializer list has exactly // one element that is itself an initializer list, [...] and the // conversion is to X or reference to cv X, user-defined conversion // sequences are not cnosidered. if (SuppressUserConversions && ListInitializing) { SuppressUserConversions = NumArgs == 1 && isa(Args[0]) && isFirstArgumentCompatibleWithType(S.Context, Info.Constructor, ToType); } if (Info.ConstructorTmpl) S.AddTemplateOverloadCandidate( Info.ConstructorTmpl, Info.FoundDecl, /*ExplicitArgs*/ nullptr, llvm::makeArrayRef(Args, NumArgs), CandidateSet, SuppressUserConversions, /*PartialOverloading*/ false, AllowExplicit == AllowedExplicit::All); else // Allow one user-defined conversion when user specifies a // From->ToType conversion via an static cast (c-style, etc). S.AddOverloadCandidate(Info.Constructor, Info.FoundDecl, llvm::makeArrayRef(Args, NumArgs), CandidateSet, SuppressUserConversions, /*PartialOverloading*/ false, AllowExplicit == AllowedExplicit::All); } } } } // Enumerate conversion functions, if we're allowed to. if (ConstructorsOnly || isa(From)) { } else if (!S.isCompleteType(From->getBeginLoc(), From->getType())) { // No conversion functions from incomplete types. } else if (const RecordType *FromRecordType = From->getType()->getAs()) { if (CXXRecordDecl *FromRecordDecl = dyn_cast(FromRecordType->getDecl())) { // Add all of the conversion functions as candidates. const auto &Conversions = FromRecordDecl->getVisibleConversionFunctions(); for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) { DeclAccessPair FoundDecl = I.getPair(); NamedDecl *D = FoundDecl.getDecl(); CXXRecordDecl *ActingContext = cast(D->getDeclContext()); if (isa(D)) D = cast(D)->getTargetDecl(); CXXConversionDecl *Conv; FunctionTemplateDecl *ConvTemplate; if ((ConvTemplate = dyn_cast(D))) Conv = cast(ConvTemplate->getTemplatedDecl()); else Conv = cast(D); if (ConvTemplate) S.AddTemplateConversionCandidate( ConvTemplate, FoundDecl, ActingContext, From, ToType, CandidateSet, AllowObjCConversionOnExplicit, AllowExplicit != AllowedExplicit::None); else S.AddConversionCandidate(Conv, FoundDecl, ActingContext, From, ToType, CandidateSet, AllowObjCConversionOnExplicit, AllowExplicit != AllowedExplicit::None); } } } bool HadMultipleCandidates = (CandidateSet.size() > 1); OverloadCandidateSet::iterator Best; switch (auto Result = CandidateSet.BestViableFunction(S, From->getBeginLoc(), Best)) { case OR_Success: case OR_Deleted: // Record the standard conversion we used and the conversion function. if (CXXConstructorDecl *Constructor = dyn_cast(Best->Function)) { // C++ [over.ics.user]p1: // If the user-defined conversion is specified by a // constructor (12.3.1), the initial standard conversion // sequence converts the source type to the type required by // the argument of the constructor. // QualType ThisType = Constructor->getThisType(); if (isa(From)) { // Initializer lists don't have conversions as such. User.Before.setAsIdentityConversion(); } else { if (Best->Conversions[0].isEllipsis()) User.EllipsisConversion = true; else { User.Before = Best->Conversions[0].Standard; User.EllipsisConversion = false; } } User.HadMultipleCandidates = HadMultipleCandidates; User.ConversionFunction = Constructor; User.FoundConversionFunction = Best->FoundDecl; User.After.setAsIdentityConversion(); User.After.setFromType(ThisType->castAs()->getPointeeType()); User.After.setAllToTypes(ToType); return Result; } if (CXXConversionDecl *Conversion = dyn_cast(Best->Function)) { // C++ [over.ics.user]p1: // // [...] If the user-defined conversion is specified by a // conversion function (12.3.2), the initial standard // conversion sequence converts the source type to the // implicit object parameter of the conversion function. User.Before = Best->Conversions[0].Standard; User.HadMultipleCandidates = HadMultipleCandidates; User.ConversionFunction = Conversion; User.FoundConversionFunction = Best->FoundDecl; User.EllipsisConversion = false; // C++ [over.ics.user]p2: // The second standard conversion sequence converts the // result of the user-defined conversion to the target type // for the sequence. Since an implicit conversion sequence // is an initialization, the special rules for // initialization by user-defined conversion apply when // selecting the best user-defined conversion for a // user-defined conversion sequence (see 13.3.3 and // 13.3.3.1). User.After = Best->FinalConversion; return Result; } llvm_unreachable("Not a constructor or conversion function?"); case OR_No_Viable_Function: return OR_No_Viable_Function; case OR_Ambiguous: return OR_Ambiguous; } llvm_unreachable("Invalid OverloadResult!"); } bool Sema::DiagnoseMultipleUserDefinedConversion(Expr *From, QualType ToType) { ImplicitConversionSequence ICS; OverloadCandidateSet CandidateSet(From->getExprLoc(), OverloadCandidateSet::CSK_Normal); OverloadingResult OvResult = IsUserDefinedConversion(*this, From, ToType, ICS.UserDefined, CandidateSet, AllowedExplicit::None, false); if (!(OvResult == OR_Ambiguous || (OvResult == OR_No_Viable_Function && !CandidateSet.empty()))) return false; auto Cands = CandidateSet.CompleteCandidates( *this, OvResult == OR_Ambiguous ? OCD_AmbiguousCandidates : OCD_AllCandidates, From); if (OvResult == OR_Ambiguous) Diag(From->getBeginLoc(), diag::err_typecheck_ambiguous_condition) << From->getType() << ToType << From->getSourceRange(); else { // OR_No_Viable_Function && !CandidateSet.empty() if (!RequireCompleteType(From->getBeginLoc(), ToType, diag::err_typecheck_nonviable_condition_incomplete, From->getType(), From->getSourceRange())) Diag(From->getBeginLoc(), diag::err_typecheck_nonviable_condition) << false << From->getType() << From->getSourceRange() << ToType; } CandidateSet.NoteCandidates( *this, From, Cands); return true; } // Helper for compareConversionFunctions that gets the FunctionType that the // conversion-operator return value 'points' to, or nullptr. static const FunctionType * getConversionOpReturnTyAsFunction(CXXConversionDecl *Conv) { const FunctionType *ConvFuncTy = Conv->getType()->castAs(); const PointerType *RetPtrTy = ConvFuncTy->getReturnType()->getAs(); if (!RetPtrTy) return nullptr; return RetPtrTy->getPointeeType()->getAs(); } /// Compare the user-defined conversion functions or constructors /// of two user-defined conversion sequences to determine whether any ordering /// is possible. static ImplicitConversionSequence::CompareKind compareConversionFunctions(Sema &S, FunctionDecl *Function1, FunctionDecl *Function2) { CXXConversionDecl *Conv1 = dyn_cast_or_null(Function1); CXXConversionDecl *Conv2 = dyn_cast_or_null(Function2); if (!Conv1 || !Conv2) return ImplicitConversionSequence::Indistinguishable; if (!Conv1->getParent()->isLambda() || !Conv2->getParent()->isLambda()) return ImplicitConversionSequence::Indistinguishable; // Objective-C++: // If both conversion functions are implicitly-declared conversions from // a lambda closure type to a function pointer and a block pointer, // respectively, always prefer the conversion to a function pointer, // because the function pointer is more lightweight and is more likely // to keep code working. if (S.getLangOpts().ObjC && S.getLangOpts().CPlusPlus11) { bool Block1 = Conv1->getConversionType()->isBlockPointerType(); bool Block2 = Conv2->getConversionType()->isBlockPointerType(); if (Block1 != Block2) return Block1 ? ImplicitConversionSequence::Worse : ImplicitConversionSequence::Better; } // In order to support multiple calling conventions for the lambda conversion // operator (such as when the free and member function calling convention is // different), prefer the 'free' mechanism, followed by the calling-convention // of operator(). The latter is in place to support the MSVC-like solution of // defining ALL of the possible conversions in regards to calling-convention. const FunctionType *Conv1FuncRet = getConversionOpReturnTyAsFunction(Conv1); const FunctionType *Conv2FuncRet = getConversionOpReturnTyAsFunction(Conv2); if (Conv1FuncRet && Conv2FuncRet && Conv1FuncRet->getCallConv() != Conv2FuncRet->getCallConv()) { CallingConv Conv1CC = Conv1FuncRet->getCallConv(); CallingConv Conv2CC = Conv2FuncRet->getCallConv(); CXXMethodDecl *CallOp = Conv2->getParent()->getLambdaCallOperator(); const FunctionProtoType *CallOpProto = CallOp->getType()->getAs(); CallingConv CallOpCC = CallOp->getType()->castAs()->getCallConv(); CallingConv DefaultFree = S.Context.getDefaultCallingConvention( CallOpProto->isVariadic(), /*IsCXXMethod=*/false); CallingConv DefaultMember = S.Context.getDefaultCallingConvention( CallOpProto->isVariadic(), /*IsCXXMethod=*/true); CallingConv PrefOrder[] = {DefaultFree, DefaultMember, CallOpCC}; for (CallingConv CC : PrefOrder) { if (Conv1CC == CC) return ImplicitConversionSequence::Better; if (Conv2CC == CC) return ImplicitConversionSequence::Worse; } } return ImplicitConversionSequence::Indistinguishable; } static bool hasDeprecatedStringLiteralToCharPtrConversion( const ImplicitConversionSequence &ICS) { return (ICS.isStandard() && ICS.Standard.DeprecatedStringLiteralToCharPtr) || (ICS.isUserDefined() && ICS.UserDefined.Before.DeprecatedStringLiteralToCharPtr); } /// CompareImplicitConversionSequences - Compare two implicit /// conversion sequences to determine whether one is better than the /// other or if they are indistinguishable (C++ 13.3.3.2). static ImplicitConversionSequence::CompareKind CompareImplicitConversionSequences(Sema &S, SourceLocation Loc, const ImplicitConversionSequence& ICS1, const ImplicitConversionSequence& ICS2) { // (C++ 13.3.3.2p2): When comparing the basic forms of implicit // conversion sequences (as defined in 13.3.3.1) // -- a standard conversion sequence (13.3.3.1.1) is a better // conversion sequence than a user-defined conversion sequence or // an ellipsis conversion sequence, and // -- a user-defined conversion sequence (13.3.3.1.2) is a better // conversion sequence than an ellipsis conversion sequence // (13.3.3.1.3). // // C++0x [over.best.ics]p10: // For the purpose of ranking implicit conversion sequences as // described in 13.3.3.2, the ambiguous conversion sequence is // treated as a user-defined sequence that is indistinguishable // from any other user-defined conversion sequence. // String literal to 'char *' conversion has been deprecated in C++03. It has // been removed from C++11. We still accept this conversion, if it happens at // the best viable function. Otherwise, this conversion is considered worse // than ellipsis conversion. Consider this as an extension; this is not in the // standard. For example: // // int &f(...); // #1 // void f(char*); // #2 // void g() { int &r = f("foo"); } // // In C++03, we pick #2 as the best viable function. // In C++11, we pick #1 as the best viable function, because ellipsis // conversion is better than string-literal to char* conversion (since there // is no such conversion in C++11). If there was no #1 at all or #1 couldn't // convert arguments, #2 would be the best viable function in C++11. // If the best viable function has this conversion, a warning will be issued // in C++03, or an ExtWarn (+SFINAE failure) will be issued in C++11. if (S.getLangOpts().CPlusPlus11 && !S.getLangOpts().WritableStrings && hasDeprecatedStringLiteralToCharPtrConversion(ICS1) != hasDeprecatedStringLiteralToCharPtrConversion(ICS2)) return hasDeprecatedStringLiteralToCharPtrConversion(ICS1) ? ImplicitConversionSequence::Worse : ImplicitConversionSequence::Better; if (ICS1.getKindRank() < ICS2.getKindRank()) return ImplicitConversionSequence::Better; if (ICS2.getKindRank() < ICS1.getKindRank()) return ImplicitConversionSequence::Worse; // The following checks require both conversion sequences to be of // the same kind. if (ICS1.getKind() != ICS2.getKind()) return ImplicitConversionSequence::Indistinguishable; ImplicitConversionSequence::CompareKind Result = ImplicitConversionSequence::Indistinguishable; // Two implicit conversion sequences of the same form are // indistinguishable conversion sequences unless one of the // following rules apply: (C++ 13.3.3.2p3): // List-initialization sequence L1 is a better conversion sequence than // list-initialization sequence L2 if: // - L1 converts to std::initializer_list for some X and L2 does not, or, // if not that, // - L1 converts to type "array of N1 T", L2 converts to type "array of N2 T", // and N1 is smaller than N2., // even if one of the other rules in this paragraph would otherwise apply. if (!ICS1.isBad()) { if (ICS1.isStdInitializerListElement() && !ICS2.isStdInitializerListElement()) return ImplicitConversionSequence::Better; if (!ICS1.isStdInitializerListElement() && ICS2.isStdInitializerListElement()) return ImplicitConversionSequence::Worse; } if (ICS1.isStandard()) // Standard conversion sequence S1 is a better conversion sequence than // standard conversion sequence S2 if [...] Result = CompareStandardConversionSequences(S, Loc, ICS1.Standard, ICS2.Standard); else if (ICS1.isUserDefined()) { // User-defined conversion sequence U1 is a better conversion // sequence than another user-defined conversion sequence U2 if // they contain the same user-defined conversion function or // constructor and if the second standard conversion sequence of // U1 is better than the second standard conversion sequence of // U2 (C++ 13.3.3.2p3). if (ICS1.UserDefined.ConversionFunction == ICS2.UserDefined.ConversionFunction) Result = CompareStandardConversionSequences(S, Loc, ICS1.UserDefined.After, ICS2.UserDefined.After); else Result = compareConversionFunctions(S, ICS1.UserDefined.ConversionFunction, ICS2.UserDefined.ConversionFunction); } return Result; } // Per 13.3.3.2p3, compare the given standard conversion sequences to // determine if one is a proper subset of the other. static ImplicitConversionSequence::CompareKind compareStandardConversionSubsets(ASTContext &Context, const StandardConversionSequence& SCS1, const StandardConversionSequence& SCS2) { ImplicitConversionSequence::CompareKind Result = ImplicitConversionSequence::Indistinguishable; // the identity conversion sequence is considered to be a subsequence of // any non-identity conversion sequence if (SCS1.isIdentityConversion() && !SCS2.isIdentityConversion()) return ImplicitConversionSequence::Better; else if (!SCS1.isIdentityConversion() && SCS2.isIdentityConversion()) return ImplicitConversionSequence::Worse; if (SCS1.Second != SCS2.Second) { if (SCS1.Second == ICK_Identity) Result = ImplicitConversionSequence::Better; else if (SCS2.Second == ICK_Identity) Result = ImplicitConversionSequence::Worse; else return ImplicitConversionSequence::Indistinguishable; } else if (!Context.hasSimilarType(SCS1.getToType(1), SCS2.getToType(1))) return ImplicitConversionSequence::Indistinguishable; if (SCS1.Third == SCS2.Third) { return Context.hasSameType(SCS1.getToType(2), SCS2.getToType(2))? Result : ImplicitConversionSequence::Indistinguishable; } if (SCS1.Third == ICK_Identity) return Result == ImplicitConversionSequence::Worse ? ImplicitConversionSequence::Indistinguishable : ImplicitConversionSequence::Better; if (SCS2.Third == ICK_Identity) return Result == ImplicitConversionSequence::Better ? ImplicitConversionSequence::Indistinguishable : ImplicitConversionSequence::Worse; return ImplicitConversionSequence::Indistinguishable; } /// Determine whether one of the given reference bindings is better /// than the other based on what kind of bindings they are. static bool isBetterReferenceBindingKind(const StandardConversionSequence &SCS1, const StandardConversionSequence &SCS2) { // C++0x [over.ics.rank]p3b4: // -- S1 and S2 are reference bindings (8.5.3) and neither refers to an // implicit object parameter of a non-static member function declared // without a ref-qualifier, and *either* S1 binds an rvalue reference // to an rvalue and S2 binds an lvalue reference *or S1 binds an // lvalue reference to a function lvalue and S2 binds an rvalue // reference*. // // FIXME: Rvalue references. We're going rogue with the above edits, // because the semantics in the current C++0x working paper (N3225 at the // time of this writing) break the standard definition of std::forward // and std::reference_wrapper when dealing with references to functions. // Proposed wording changes submitted to CWG for consideration. if (SCS1.BindsImplicitObjectArgumentWithoutRefQualifier || SCS2.BindsImplicitObjectArgumentWithoutRefQualifier) return false; return (!SCS1.IsLvalueReference && SCS1.BindsToRvalue && SCS2.IsLvalueReference) || (SCS1.IsLvalueReference && SCS1.BindsToFunctionLvalue && !SCS2.IsLvalueReference && SCS2.BindsToFunctionLvalue); } enum class FixedEnumPromotion { None, ToUnderlyingType, ToPromotedUnderlyingType }; /// Returns kind of fixed enum promotion the \a SCS uses. static FixedEnumPromotion getFixedEnumPromtion(Sema &S, const StandardConversionSequence &SCS) { if (SCS.Second != ICK_Integral_Promotion) return FixedEnumPromotion::None; QualType FromType = SCS.getFromType(); if (!FromType->isEnumeralType()) return FixedEnumPromotion::None; EnumDecl *Enum = FromType->castAs()->getDecl(); if (!Enum->isFixed()) return FixedEnumPromotion::None; QualType UnderlyingType = Enum->getIntegerType(); if (S.Context.hasSameType(SCS.getToType(1), UnderlyingType)) return FixedEnumPromotion::ToUnderlyingType; return FixedEnumPromotion::ToPromotedUnderlyingType; } /// CompareStandardConversionSequences - Compare two standard /// conversion sequences to determine whether one is better than the /// other or if they are indistinguishable (C++ 13.3.3.2p3). static ImplicitConversionSequence::CompareKind CompareStandardConversionSequences(Sema &S, SourceLocation Loc, const StandardConversionSequence& SCS1, const StandardConversionSequence& SCS2) { // Standard conversion sequence S1 is a better conversion sequence // than standard conversion sequence S2 if (C++ 13.3.3.2p3): // -- S1 is a proper subsequence of S2 (comparing the conversion // sequences in the canonical form defined by 13.3.3.1.1, // excluding any Lvalue Transformation; the identity conversion // sequence is considered to be a subsequence of any // non-identity conversion sequence) or, if not that, if (ImplicitConversionSequence::CompareKind CK = compareStandardConversionSubsets(S.Context, SCS1, SCS2)) return CK; // -- the rank of S1 is better than the rank of S2 (by the rules // defined below), or, if not that, ImplicitConversionRank Rank1 = SCS1.getRank(); ImplicitConversionRank Rank2 = SCS2.getRank(); if (Rank1 < Rank2) return ImplicitConversionSequence::Better; else if (Rank2 < Rank1) return ImplicitConversionSequence::Worse; // (C++ 13.3.3.2p4): Two conversion sequences with the same rank // are indistinguishable unless one of the following rules // applies: // A conversion that is not a conversion of a pointer, or // pointer to member, to bool is better than another conversion // that is such a conversion. if (SCS1.isPointerConversionToBool() != SCS2.isPointerConversionToBool()) return SCS2.isPointerConversionToBool() ? ImplicitConversionSequence::Better : ImplicitConversionSequence::Worse; // C++14 [over.ics.rank]p4b2: // This is retroactively applied to C++11 by CWG 1601. // // A conversion that promotes an enumeration whose underlying type is fixed // to its underlying type is better than one that promotes to the promoted // underlying type, if the two are different. FixedEnumPromotion FEP1 = getFixedEnumPromtion(S, SCS1); FixedEnumPromotion FEP2 = getFixedEnumPromtion(S, SCS2); if (FEP1 != FixedEnumPromotion::None && FEP2 != FixedEnumPromotion::None && FEP1 != FEP2) return FEP1 == FixedEnumPromotion::ToUnderlyingType ? ImplicitConversionSequence::Better : ImplicitConversionSequence::Worse; // C++ [over.ics.rank]p4b2: // // If class B is derived directly or indirectly from class A, // conversion of B* to A* is better than conversion of B* to // void*, and conversion of A* to void* is better than conversion // of B* to void*. bool SCS1ConvertsToVoid = SCS1.isPointerConversionToVoidPointer(S.Context); bool SCS2ConvertsToVoid = SCS2.isPointerConversionToVoidPointer(S.Context); if (SCS1ConvertsToVoid != SCS2ConvertsToVoid) { // Exactly one of the conversion sequences is a conversion to // a void pointer; it's the worse conversion. return SCS2ConvertsToVoid ? ImplicitConversionSequence::Better : ImplicitConversionSequence::Worse; } else if (!SCS1ConvertsToVoid && !SCS2ConvertsToVoid) { // Neither conversion sequence converts to a void pointer; compare // their derived-to-base conversions. if (ImplicitConversionSequence::CompareKind DerivedCK = CompareDerivedToBaseConversions(S, Loc, SCS1, SCS2)) return DerivedCK; } else if (SCS1ConvertsToVoid && SCS2ConvertsToVoid && !S.Context.hasSameType(SCS1.getFromType(), SCS2.getFromType())) { // Both conversion sequences are conversions to void // pointers. Compare the source types to determine if there's an // inheritance relationship in their sources. QualType FromType1 = SCS1.getFromType(); QualType FromType2 = SCS2.getFromType(); // Adjust the types we're converting from via the array-to-pointer // conversion, if we need to. if (SCS1.First == ICK_Array_To_Pointer) FromType1 = S.Context.getArrayDecayedType(FromType1); if (SCS2.First == ICK_Array_To_Pointer) FromType2 = S.Context.getArrayDecayedType(FromType2); QualType FromPointee1 = FromType1->getPointeeType().getUnqualifiedType(); QualType FromPointee2 = FromType2->getPointeeType().getUnqualifiedType(); if (S.IsDerivedFrom(Loc, FromPointee2, FromPointee1)) return ImplicitConversionSequence::Better; else if (S.IsDerivedFrom(Loc, FromPointee1, FromPointee2)) return ImplicitConversionSequence::Worse; // Objective-C++: If one interface is more specific than the // other, it is the better one. const ObjCObjectPointerType* FromObjCPtr1 = FromType1->getAs(); const ObjCObjectPointerType* FromObjCPtr2 = FromType2->getAs(); if (FromObjCPtr1 && FromObjCPtr2) { bool AssignLeft = S.Context.canAssignObjCInterfaces(FromObjCPtr1, FromObjCPtr2); bool AssignRight = S.Context.canAssignObjCInterfaces(FromObjCPtr2, FromObjCPtr1); if (AssignLeft != AssignRight) { return AssignLeft? ImplicitConversionSequence::Better : ImplicitConversionSequence::Worse; } } } if (SCS1.ReferenceBinding && SCS2.ReferenceBinding) { // Check for a better reference binding based on the kind of bindings. if (isBetterReferenceBindingKind(SCS1, SCS2)) return ImplicitConversionSequence::Better; else if (isBetterReferenceBindingKind(SCS2, SCS1)) return ImplicitConversionSequence::Worse; } // Compare based on qualification conversions (C++ 13.3.3.2p3, // bullet 3). if (ImplicitConversionSequence::CompareKind QualCK = CompareQualificationConversions(S, SCS1, SCS2)) return QualCK; if (SCS1.ReferenceBinding && SCS2.ReferenceBinding) { // C++ [over.ics.rank]p3b4: // -- S1 and S2 are reference bindings (8.5.3), and the types to // which the references refer are the same type except for // top-level cv-qualifiers, and the type to which the reference // initialized by S2 refers is more cv-qualified than the type // to which the reference initialized by S1 refers. QualType T1 = SCS1.getToType(2); QualType T2 = SCS2.getToType(2); T1 = S.Context.getCanonicalType(T1); T2 = S.Context.getCanonicalType(T2); Qualifiers T1Quals, T2Quals; QualType UnqualT1 = S.Context.getUnqualifiedArrayType(T1, T1Quals); QualType UnqualT2 = S.Context.getUnqualifiedArrayType(T2, T2Quals); if (UnqualT1 == UnqualT2) { // Objective-C++ ARC: If the references refer to objects with different // lifetimes, prefer bindings that don't change lifetime. if (SCS1.ObjCLifetimeConversionBinding != SCS2.ObjCLifetimeConversionBinding) { return SCS1.ObjCLifetimeConversionBinding ? ImplicitConversionSequence::Worse : ImplicitConversionSequence::Better; } // If the type is an array type, promote the element qualifiers to the // type for comparison. if (isa(T1) && T1Quals) T1 = S.Context.getQualifiedType(UnqualT1, T1Quals); if (isa(T2) && T2Quals) T2 = S.Context.getQualifiedType(UnqualT2, T2Quals); if (T2.isMoreQualifiedThan(T1)) return ImplicitConversionSequence::Better; if (T1.isMoreQualifiedThan(T2)) return ImplicitConversionSequence::Worse; } } // In Microsoft mode (below 19.28), prefer an integral conversion to a // floating-to-integral conversion if the integral conversion // is between types of the same size. // For example: // void f(float); // void f(int); // int main { // long a; // f(a); // } // Here, MSVC will call f(int) instead of generating a compile error // as clang will do in standard mode. if (S.getLangOpts().MSVCCompat && !S.getLangOpts().isCompatibleWithMSVC(LangOptions::MSVC2019_8) && SCS1.Second == ICK_Integral_Conversion && SCS2.Second == ICK_Floating_Integral && S.Context.getTypeSize(SCS1.getFromType()) == S.Context.getTypeSize(SCS1.getToType(2))) return ImplicitConversionSequence::Better; // Prefer a compatible vector conversion over a lax vector conversion // For example: // // typedef float __v4sf __attribute__((__vector_size__(16))); // void f(vector float); // void f(vector signed int); // int main() { // __v4sf a; // f(a); // } // Here, we'd like to choose f(vector float) and not // report an ambiguous call error if (SCS1.Second == ICK_Vector_Conversion && SCS2.Second == ICK_Vector_Conversion) { bool SCS1IsCompatibleVectorConversion = S.Context.areCompatibleVectorTypes( SCS1.getFromType(), SCS1.getToType(2)); bool SCS2IsCompatibleVectorConversion = S.Context.areCompatibleVectorTypes( SCS2.getFromType(), SCS2.getToType(2)); if (SCS1IsCompatibleVectorConversion != SCS2IsCompatibleVectorConversion) return SCS1IsCompatibleVectorConversion ? ImplicitConversionSequence::Better : ImplicitConversionSequence::Worse; } if (SCS1.Second == ICK_SVE_Vector_Conversion && SCS2.Second == ICK_SVE_Vector_Conversion) { bool SCS1IsCompatibleSVEVectorConversion = S.Context.areCompatibleSveTypes(SCS1.getFromType(), SCS1.getToType(2)); bool SCS2IsCompatibleSVEVectorConversion = S.Context.areCompatibleSveTypes(SCS2.getFromType(), SCS2.getToType(2)); if (SCS1IsCompatibleSVEVectorConversion != SCS2IsCompatibleSVEVectorConversion) return SCS1IsCompatibleSVEVectorConversion ? ImplicitConversionSequence::Better : ImplicitConversionSequence::Worse; } return ImplicitConversionSequence::Indistinguishable; } /// CompareQualificationConversions - Compares two standard conversion /// sequences to determine whether they can be ranked based on their /// qualification conversions (C++ 13.3.3.2p3 bullet 3). static ImplicitConversionSequence::CompareKind CompareQualificationConversions(Sema &S, const StandardConversionSequence& SCS1, const StandardConversionSequence& SCS2) { // C++ 13.3.3.2p3: // -- S1 and S2 differ only in their qualification conversion and // yield similar types T1 and T2 (C++ 4.4), respectively, and the // cv-qualification signature of type T1 is a proper subset of // the cv-qualification signature of type T2, and S1 is not the // deprecated string literal array-to-pointer conversion (4.2). if (SCS1.First != SCS2.First || SCS1.Second != SCS2.Second || SCS1.Third != SCS2.Third || SCS1.Third != ICK_Qualification) return ImplicitConversionSequence::Indistinguishable; // FIXME: the example in the standard doesn't use a qualification // conversion (!) QualType T1 = SCS1.getToType(2); QualType T2 = SCS2.getToType(2); T1 = S.Context.getCanonicalType(T1); T2 = S.Context.getCanonicalType(T2); assert(!T1->isReferenceType() && !T2->isReferenceType()); Qualifiers T1Quals, T2Quals; QualType UnqualT1 = S.Context.getUnqualifiedArrayType(T1, T1Quals); QualType UnqualT2 = S.Context.getUnqualifiedArrayType(T2, T2Quals); // If the types are the same, we won't learn anything by unwrapping // them. if (UnqualT1 == UnqualT2) return ImplicitConversionSequence::Indistinguishable; ImplicitConversionSequence::CompareKind Result = ImplicitConversionSequence::Indistinguishable; // Objective-C++ ARC: // Prefer qualification conversions not involving a change in lifetime // to qualification conversions that do not change lifetime. if (SCS1.QualificationIncludesObjCLifetime != SCS2.QualificationIncludesObjCLifetime) { Result = SCS1.QualificationIncludesObjCLifetime ? ImplicitConversionSequence::Worse : ImplicitConversionSequence::Better; } while (S.Context.UnwrapSimilarTypes(T1, T2)) { // Within each iteration of the loop, we check the qualifiers to // determine if this still looks like a qualification // conversion. Then, if all is well, we unwrap one more level of // pointers or pointers-to-members and do it all again // until there are no more pointers or pointers-to-members left // to unwrap. This essentially mimics what // IsQualificationConversion does, but here we're checking for a // strict subset of qualifiers. if (T1.getQualifiers().withoutObjCLifetime() == T2.getQualifiers().withoutObjCLifetime()) // The qualifiers are the same, so this doesn't tell us anything // about how the sequences rank. // ObjC ownership quals are omitted above as they interfere with // the ARC overload rule. ; else if (T2.isMoreQualifiedThan(T1)) { // T1 has fewer qualifiers, so it could be the better sequence. if (Result == ImplicitConversionSequence::Worse) // Neither has qualifiers that are a subset of the other's // qualifiers. return ImplicitConversionSequence::Indistinguishable; Result = ImplicitConversionSequence::Better; } else if (T1.isMoreQualifiedThan(T2)) { // T2 has fewer qualifiers, so it could be the better sequence. if (Result == ImplicitConversionSequence::Better) // Neither has qualifiers that are a subset of the other's // qualifiers. return ImplicitConversionSequence::Indistinguishable; Result = ImplicitConversionSequence::Worse; } else { // Qualifiers are disjoint. return ImplicitConversionSequence::Indistinguishable; } // If the types after this point are equivalent, we're done. if (S.Context.hasSameUnqualifiedType(T1, T2)) break; } // Check that the winning standard conversion sequence isn't using // the deprecated string literal array to pointer conversion. switch (Result) { case ImplicitConversionSequence::Better: if (SCS1.DeprecatedStringLiteralToCharPtr) Result = ImplicitConversionSequence::Indistinguishable; break; case ImplicitConversionSequence::Indistinguishable: break; case ImplicitConversionSequence::Worse: if (SCS2.DeprecatedStringLiteralToCharPtr) Result = ImplicitConversionSequence::Indistinguishable; break; } return Result; } /// CompareDerivedToBaseConversions - Compares two standard conversion /// sequences to determine whether they can be ranked based on their /// various kinds of derived-to-base conversions (C++ /// [over.ics.rank]p4b3). As part of these checks, we also look at /// conversions between Objective-C interface types. static ImplicitConversionSequence::CompareKind CompareDerivedToBaseConversions(Sema &S, SourceLocation Loc, const StandardConversionSequence& SCS1, const StandardConversionSequence& SCS2) { QualType FromType1 = SCS1.getFromType(); QualType ToType1 = SCS1.getToType(1); QualType FromType2 = SCS2.getFromType(); QualType ToType2 = SCS2.getToType(1); // Adjust the types we're converting from via the array-to-pointer // conversion, if we need to. if (SCS1.First == ICK_Array_To_Pointer) FromType1 = S.Context.getArrayDecayedType(FromType1); if (SCS2.First == ICK_Array_To_Pointer) FromType2 = S.Context.getArrayDecayedType(FromType2); // Canonicalize all of the types. FromType1 = S.Context.getCanonicalType(FromType1); ToType1 = S.Context.getCanonicalType(ToType1); FromType2 = S.Context.getCanonicalType(FromType2); ToType2 = S.Context.getCanonicalType(ToType2); // C++ [over.ics.rank]p4b3: // // If class B is derived directly or indirectly from class A and // class C is derived directly or indirectly from B, // // Compare based on pointer conversions. if (SCS1.Second == ICK_Pointer_Conversion && SCS2.Second == ICK_Pointer_Conversion && /*FIXME: Remove if Objective-C id conversions get their own rank*/ FromType1->isPointerType() && FromType2->isPointerType() && ToType1->isPointerType() && ToType2->isPointerType()) { QualType FromPointee1 = FromType1->castAs()->getPointeeType().getUnqualifiedType(); QualType ToPointee1 = ToType1->castAs()->getPointeeType().getUnqualifiedType(); QualType FromPointee2 = FromType2->castAs()->getPointeeType().getUnqualifiedType(); QualType ToPointee2 = ToType2->castAs()->getPointeeType().getUnqualifiedType(); // -- conversion of C* to B* is better than conversion of C* to A*, if (FromPointee1 == FromPointee2 && ToPointee1 != ToPointee2) { if (S.IsDerivedFrom(Loc, ToPointee1, ToPointee2)) return ImplicitConversionSequence::Better; else if (S.IsDerivedFrom(Loc, ToPointee2, ToPointee1)) return ImplicitConversionSequence::Worse; } // -- conversion of B* to A* is better than conversion of C* to A*, if (FromPointee1 != FromPointee2 && ToPointee1 == ToPointee2) { if (S.IsDerivedFrom(Loc, FromPointee2, FromPointee1)) return ImplicitConversionSequence::Better; else if (S.IsDerivedFrom(Loc, FromPointee1, FromPointee2)) return ImplicitConversionSequence::Worse; } } else if (SCS1.Second == ICK_Pointer_Conversion && SCS2.Second == ICK_Pointer_Conversion) { const ObjCObjectPointerType *FromPtr1 = FromType1->getAs(); const ObjCObjectPointerType *FromPtr2 = FromType2->getAs(); const ObjCObjectPointerType *ToPtr1 = ToType1->getAs(); const ObjCObjectPointerType *ToPtr2 = ToType2->getAs(); if (FromPtr1 && FromPtr2 && ToPtr1 && ToPtr2) { // Apply the same conversion ranking rules for Objective-C pointer types // that we do for C++ pointers to class types. However, we employ the // Objective-C pseudo-subtyping relationship used for assignment of // Objective-C pointer types. bool FromAssignLeft = S.Context.canAssignObjCInterfaces(FromPtr1, FromPtr2); bool FromAssignRight = S.Context.canAssignObjCInterfaces(FromPtr2, FromPtr1); bool ToAssignLeft = S.Context.canAssignObjCInterfaces(ToPtr1, ToPtr2); bool ToAssignRight = S.Context.canAssignObjCInterfaces(ToPtr2, ToPtr1); // A conversion to an a non-id object pointer type or qualified 'id' // type is better than a conversion to 'id'. if (ToPtr1->isObjCIdType() && (ToPtr2->isObjCQualifiedIdType() || ToPtr2->getInterfaceDecl())) return ImplicitConversionSequence::Worse; if (ToPtr2->isObjCIdType() && (ToPtr1->isObjCQualifiedIdType() || ToPtr1->getInterfaceDecl())) return ImplicitConversionSequence::Better; // A conversion to a non-id object pointer type is better than a // conversion to a qualified 'id' type if (ToPtr1->isObjCQualifiedIdType() && ToPtr2->getInterfaceDecl()) return ImplicitConversionSequence::Worse; if (ToPtr2->isObjCQualifiedIdType() && ToPtr1->getInterfaceDecl()) return ImplicitConversionSequence::Better; // A conversion to an a non-Class object pointer type or qualified 'Class' // type is better than a conversion to 'Class'. if (ToPtr1->isObjCClassType() && (ToPtr2->isObjCQualifiedClassType() || ToPtr2->getInterfaceDecl())) return ImplicitConversionSequence::Worse; if (ToPtr2->isObjCClassType() && (ToPtr1->isObjCQualifiedClassType() || ToPtr1->getInterfaceDecl())) return ImplicitConversionSequence::Better; // A conversion to a non-Class object pointer type is better than a // conversion to a qualified 'Class' type. if (ToPtr1->isObjCQualifiedClassType() && ToPtr2->getInterfaceDecl()) return ImplicitConversionSequence::Worse; if (ToPtr2->isObjCQualifiedClassType() && ToPtr1->getInterfaceDecl()) return ImplicitConversionSequence::Better; // -- "conversion of C* to B* is better than conversion of C* to A*," if (S.Context.hasSameType(FromType1, FromType2) && !FromPtr1->isObjCIdType() && !FromPtr1->isObjCClassType() && (ToAssignLeft != ToAssignRight)) { if (FromPtr1->isSpecialized()) { // "conversion of B * to B * is better than conversion of B * to // C *. bool IsFirstSame = FromPtr1->getInterfaceDecl() == ToPtr1->getInterfaceDecl(); bool IsSecondSame = FromPtr1->getInterfaceDecl() == ToPtr2->getInterfaceDecl(); if (IsFirstSame) { if (!IsSecondSame) return ImplicitConversionSequence::Better; } else if (IsSecondSame) return ImplicitConversionSequence::Worse; } return ToAssignLeft? ImplicitConversionSequence::Worse : ImplicitConversionSequence::Better; } // -- "conversion of B* to A* is better than conversion of C* to A*," if (S.Context.hasSameUnqualifiedType(ToType1, ToType2) && (FromAssignLeft != FromAssignRight)) return FromAssignLeft? ImplicitConversionSequence::Better : ImplicitConversionSequence::Worse; } } // Ranking of member-pointer types. if (SCS1.Second == ICK_Pointer_Member && SCS2.Second == ICK_Pointer_Member && FromType1->isMemberPointerType() && FromType2->isMemberPointerType() && ToType1->isMemberPointerType() && ToType2->isMemberPointerType()) { const auto *FromMemPointer1 = FromType1->castAs(); const auto *ToMemPointer1 = ToType1->castAs(); const auto *FromMemPointer2 = FromType2->castAs(); const auto *ToMemPointer2 = ToType2->castAs(); const Type *FromPointeeType1 = FromMemPointer1->getClass(); const Type *ToPointeeType1 = ToMemPointer1->getClass(); const Type *FromPointeeType2 = FromMemPointer2->getClass(); const Type *ToPointeeType2 = ToMemPointer2->getClass(); QualType FromPointee1 = QualType(FromPointeeType1, 0).getUnqualifiedType(); QualType ToPointee1 = QualType(ToPointeeType1, 0).getUnqualifiedType(); QualType FromPointee2 = QualType(FromPointeeType2, 0).getUnqualifiedType(); QualType ToPointee2 = QualType(ToPointeeType2, 0).getUnqualifiedType(); // conversion of A::* to B::* is better than conversion of A::* to C::*, if (FromPointee1 == FromPointee2 && ToPointee1 != ToPointee2) { if (S.IsDerivedFrom(Loc, ToPointee1, ToPointee2)) return ImplicitConversionSequence::Worse; else if (S.IsDerivedFrom(Loc, ToPointee2, ToPointee1)) return ImplicitConversionSequence::Better; } // conversion of B::* to C::* is better than conversion of A::* to C::* if (ToPointee1 == ToPointee2 && FromPointee1 != FromPointee2) { if (S.IsDerivedFrom(Loc, FromPointee1, FromPointee2)) return ImplicitConversionSequence::Better; else if (S.IsDerivedFrom(Loc, FromPointee2, FromPointee1)) return ImplicitConversionSequence::Worse; } } if (SCS1.Second == ICK_Derived_To_Base) { // -- conversion of C to B is better than conversion of C to A, // -- binding of an expression of type C to a reference of type // B& is better than binding an expression of type C to a // reference of type A&, if (S.Context.hasSameUnqualifiedType(FromType1, FromType2) && !S.Context.hasSameUnqualifiedType(ToType1, ToType2)) { if (S.IsDerivedFrom(Loc, ToType1, ToType2)) return ImplicitConversionSequence::Better; else if (S.IsDerivedFrom(Loc, ToType2, ToType1)) return ImplicitConversionSequence::Worse; } // -- conversion of B to A is better than conversion of C to A. // -- binding of an expression of type B to a reference of type // A& is better than binding an expression of type C to a // reference of type A&, if (!S.Context.hasSameUnqualifiedType(FromType1, FromType2) && S.Context.hasSameUnqualifiedType(ToType1, ToType2)) { if (S.IsDerivedFrom(Loc, FromType2, FromType1)) return ImplicitConversionSequence::Better; else if (S.IsDerivedFrom(Loc, FromType1, FromType2)) return ImplicitConversionSequence::Worse; } } return ImplicitConversionSequence::Indistinguishable; } /// Determine whether the given type is valid, e.g., it is not an invalid /// C++ class. static bool isTypeValid(QualType T) { if (CXXRecordDecl *Record = T->getAsCXXRecordDecl()) return !Record->isInvalidDecl(); return true; } static QualType withoutUnaligned(ASTContext &Ctx, QualType T) { if (!T.getQualifiers().hasUnaligned()) return T; Qualifiers Q; T = Ctx.getUnqualifiedArrayType(T, Q); Q.removeUnaligned(); return Ctx.getQualifiedType(T, Q); } /// CompareReferenceRelationship - Compare the two types T1 and T2 to /// determine whether they are reference-compatible, /// reference-related, or incompatible, for use in C++ initialization by /// reference (C++ [dcl.ref.init]p4). Neither type can be a reference /// type, and the first type (T1) is the pointee type of the reference /// type being initialized. Sema::ReferenceCompareResult Sema::CompareReferenceRelationship(SourceLocation Loc, QualType OrigT1, QualType OrigT2, ReferenceConversions *ConvOut) { assert(!OrigT1->isReferenceType() && "T1 must be the pointee type of the reference type"); assert(!OrigT2->isReferenceType() && "T2 cannot be a reference type"); QualType T1 = Context.getCanonicalType(OrigT1); QualType T2 = Context.getCanonicalType(OrigT2); Qualifiers T1Quals, T2Quals; QualType UnqualT1 = Context.getUnqualifiedArrayType(T1, T1Quals); QualType UnqualT2 = Context.getUnqualifiedArrayType(T2, T2Quals); ReferenceConversions ConvTmp; ReferenceConversions &Conv = ConvOut ? *ConvOut : ConvTmp; Conv = ReferenceConversions(); // C++2a [dcl.init.ref]p4: // Given types "cv1 T1" and "cv2 T2," "cv1 T1" is // reference-related to "cv2 T2" if T1 is similar to T2, or // T1 is a base class of T2. // "cv1 T1" is reference-compatible with "cv2 T2" if // a prvalue of type "pointer to cv2 T2" can be converted to the type // "pointer to cv1 T1" via a standard conversion sequence. // Check for standard conversions we can apply to pointers: derived-to-base // conversions, ObjC pointer conversions, and function pointer conversions. // (Qualification conversions are checked last.) QualType ConvertedT2; if (UnqualT1 == UnqualT2) { // Nothing to do. } else if (isCompleteType(Loc, OrigT2) && isTypeValid(UnqualT1) && isTypeValid(UnqualT2) && IsDerivedFrom(Loc, UnqualT2, UnqualT1)) Conv |= ReferenceConversions::DerivedToBase; else if (UnqualT1->isObjCObjectOrInterfaceType() && UnqualT2->isObjCObjectOrInterfaceType() && Context.canBindObjCObjectType(UnqualT1, UnqualT2)) Conv |= ReferenceConversions::ObjC; else if (UnqualT2->isFunctionType() && IsFunctionConversion(UnqualT2, UnqualT1, ConvertedT2)) { Conv |= ReferenceConversions::Function; // No need to check qualifiers; function types don't have them. return Ref_Compatible; } bool ConvertedReferent = Conv != 0; // We can have a qualification conversion. Compute whether the types are // similar at the same time. bool PreviousToQualsIncludeConst = true; bool TopLevel = true; do { if (T1 == T2) break; // We will need a qualification conversion. Conv |= ReferenceConversions::Qualification; // Track whether we performed a qualification conversion anywhere other // than the top level. This matters for ranking reference bindings in // overload resolution. if (!TopLevel) Conv |= ReferenceConversions::NestedQualification; // MS compiler ignores __unaligned qualifier for references; do the same. T1 = withoutUnaligned(Context, T1); T2 = withoutUnaligned(Context, T2); // If we find a qualifier mismatch, the types are not reference-compatible, // but are still be reference-related if they're similar. bool ObjCLifetimeConversion = false; if (!isQualificationConversionStep(T2, T1, /*CStyle=*/false, TopLevel, PreviousToQualsIncludeConst, ObjCLifetimeConversion)) return (ConvertedReferent || Context.hasSimilarType(T1, T2)) ? Ref_Related : Ref_Incompatible; // FIXME: Should we track this for any level other than the first? if (ObjCLifetimeConversion) Conv |= ReferenceConversions::ObjCLifetime; TopLevel = false; } while (Context.UnwrapSimilarTypes(T1, T2)); // At this point, if the types are reference-related, we must either have the // same inner type (ignoring qualifiers), or must have already worked out how // to convert the referent. return (ConvertedReferent || Context.hasSameUnqualifiedType(T1, T2)) ? Ref_Compatible : Ref_Incompatible; } /// Look for a user-defined conversion to a value reference-compatible /// with DeclType. Return true if something definite is found. static bool FindConversionForRefInit(Sema &S, ImplicitConversionSequence &ICS, QualType DeclType, SourceLocation DeclLoc, Expr *Init, QualType T2, bool AllowRvalues, bool AllowExplicit) { assert(T2->isRecordType() && "Can only find conversions of record types."); auto *T2RecordDecl = cast(T2->castAs()->getDecl()); OverloadCandidateSet CandidateSet( DeclLoc, OverloadCandidateSet::CSK_InitByUserDefinedConversion); const auto &Conversions = T2RecordDecl->getVisibleConversionFunctions(); for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) { NamedDecl *D = *I; CXXRecordDecl *ActingDC = cast(D->getDeclContext()); if (isa(D)) D = cast(D)->getTargetDecl(); FunctionTemplateDecl *ConvTemplate = dyn_cast(D); CXXConversionDecl *Conv; if (ConvTemplate) Conv = cast(ConvTemplate->getTemplatedDecl()); else Conv = cast(D); if (AllowRvalues) { // If we are initializing an rvalue reference, don't permit conversion // functions that return lvalues. if (!ConvTemplate && DeclType->isRValueReferenceType()) { const ReferenceType *RefType = Conv->getConversionType()->getAs(); if (RefType && !RefType->getPointeeType()->isFunctionType()) continue; } if (!ConvTemplate && S.CompareReferenceRelationship( DeclLoc, Conv->getConversionType() .getNonReferenceType() .getUnqualifiedType(), DeclType.getNonReferenceType().getUnqualifiedType()) == Sema::Ref_Incompatible) continue; } else { // If the conversion function doesn't return a reference type, // it can't be considered for this conversion. An rvalue reference // is only acceptable if its referencee is a function type. const ReferenceType *RefType = Conv->getConversionType()->getAs(); if (!RefType || (!RefType->isLValueReferenceType() && !RefType->getPointeeType()->isFunctionType())) continue; } if (ConvTemplate) S.AddTemplateConversionCandidate( ConvTemplate, I.getPair(), ActingDC, Init, DeclType, CandidateSet, /*AllowObjCConversionOnExplicit=*/false, AllowExplicit); else S.AddConversionCandidate( Conv, I.getPair(), ActingDC, Init, DeclType, CandidateSet, /*AllowObjCConversionOnExplicit=*/false, AllowExplicit); } bool HadMultipleCandidates = (CandidateSet.size() > 1); OverloadCandidateSet::iterator Best; switch (CandidateSet.BestViableFunction(S, DeclLoc, Best)) { case OR_Success: // C++ [over.ics.ref]p1: // // [...] If the parameter binds directly to the result of // applying a conversion function to the argument // expression, the implicit conversion sequence is a // user-defined conversion sequence (13.3.3.1.2), with the // second standard conversion sequence either an identity // conversion or, if the conversion function returns an // entity of a type that is a derived class of the parameter // type, a derived-to-base Conversion. if (!Best->FinalConversion.DirectBinding) return false; ICS.setUserDefined(); ICS.UserDefined.Before = Best->Conversions[0].Standard; ICS.UserDefined.After = Best->FinalConversion; ICS.UserDefined.HadMultipleCandidates = HadMultipleCandidates; ICS.UserDefined.ConversionFunction = Best->Function; ICS.UserDefined.FoundConversionFunction = Best->FoundDecl; ICS.UserDefined.EllipsisConversion = false; assert(ICS.UserDefined.After.ReferenceBinding && ICS.UserDefined.After.DirectBinding && "Expected a direct reference binding!"); return true; case OR_Ambiguous: ICS.setAmbiguous(); for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(); Cand != CandidateSet.end(); ++Cand) if (Cand->Best) ICS.Ambiguous.addConversion(Cand->FoundDecl, Cand->Function); return true; case OR_No_Viable_Function: case OR_Deleted: // There was no suitable conversion, or we found a deleted // conversion; continue with other checks. return false; } llvm_unreachable("Invalid OverloadResult!"); } /// Compute an implicit conversion sequence for reference /// initialization. static ImplicitConversionSequence TryReferenceInit(Sema &S, Expr *Init, QualType DeclType, SourceLocation DeclLoc, bool SuppressUserConversions, bool AllowExplicit) { assert(DeclType->isReferenceType() && "Reference init needs a reference"); // Most paths end in a failed conversion. ImplicitConversionSequence ICS; ICS.setBad(BadConversionSequence::no_conversion, Init, DeclType); QualType T1 = DeclType->castAs()->getPointeeType(); QualType T2 = Init->getType(); // If the initializer is the address of an overloaded function, try // to resolve the overloaded function. If all goes well, T2 is the // type of the resulting function. if (S.Context.getCanonicalType(T2) == S.Context.OverloadTy) { DeclAccessPair Found; if (FunctionDecl *Fn = S.ResolveAddressOfOverloadedFunction(Init, DeclType, false, Found)) T2 = Fn->getType(); } // Compute some basic properties of the types and the initializer. bool isRValRef = DeclType->isRValueReferenceType(); Expr::Classification InitCategory = Init->Classify(S.Context); Sema::ReferenceConversions RefConv; Sema::ReferenceCompareResult RefRelationship = S.CompareReferenceRelationship(DeclLoc, T1, T2, &RefConv); auto SetAsReferenceBinding = [&](bool BindsDirectly) { ICS.setStandard(); ICS.Standard.First = ICK_Identity; // FIXME: A reference binding can be a function conversion too. We should // consider that when ordering reference-to-function bindings. ICS.Standard.Second = (RefConv & Sema::ReferenceConversions::DerivedToBase) ? ICK_Derived_To_Base : (RefConv & Sema::ReferenceConversions::ObjC) ? ICK_Compatible_Conversion : ICK_Identity; // FIXME: As a speculative fix to a defect introduced by CWG2352, we rank // a reference binding that performs a non-top-level qualification // conversion as a qualification conversion, not as an identity conversion. ICS.Standard.Third = (RefConv & Sema::ReferenceConversions::NestedQualification) ? ICK_Qualification : ICK_Identity; ICS.Standard.setFromType(T2); ICS.Standard.setToType(0, T2); ICS.Standard.setToType(1, T1); ICS.Standard.setToType(2, T1); ICS.Standard.ReferenceBinding = true; ICS.Standard.DirectBinding = BindsDirectly; ICS.Standard.IsLvalueReference = !isRValRef; ICS.Standard.BindsToFunctionLvalue = T2->isFunctionType(); ICS.Standard.BindsToRvalue = InitCategory.isRValue(); ICS.Standard.BindsImplicitObjectArgumentWithoutRefQualifier = false; ICS.Standard.ObjCLifetimeConversionBinding = (RefConv & Sema::ReferenceConversions::ObjCLifetime) != 0; ICS.Standard.CopyConstructor = nullptr; ICS.Standard.DeprecatedStringLiteralToCharPtr = false; }; // C++0x [dcl.init.ref]p5: // A reference to type "cv1 T1" is initialized by an expression // of type "cv2 T2" as follows: // -- If reference is an lvalue reference and the initializer expression if (!isRValRef) { // -- is an lvalue (but is not a bit-field), and "cv1 T1" is // reference-compatible with "cv2 T2," or // // Per C++ [over.ics.ref]p4, we don't check the bit-field property here. if (InitCategory.isLValue() && RefRelationship == Sema::Ref_Compatible) { // C++ [over.ics.ref]p1: // When a parameter of reference type binds directly (8.5.3) // to an argument expression, the implicit conversion sequence // is the identity conversion, unless the argument expression // has a type that is a derived class of the parameter type, // in which case the implicit conversion sequence is a // derived-to-base Conversion (13.3.3.1). SetAsReferenceBinding(/*BindsDirectly=*/true); // Nothing more to do: the inaccessibility/ambiguity check for // derived-to-base conversions is suppressed when we're // computing the implicit conversion sequence (C++ // [over.best.ics]p2). return ICS; } // -- has a class type (i.e., T2 is a class type), where T1 is // not reference-related to T2, and can be implicitly // converted to an lvalue of type "cv3 T3," where "cv1 T1" // is reference-compatible with "cv3 T3" 92) (this // conversion is selected by enumerating the applicable // conversion functions (13.3.1.6) and choosing the best // one through overload resolution (13.3)), if (!SuppressUserConversions && T2->isRecordType() && S.isCompleteType(DeclLoc, T2) && RefRelationship == Sema::Ref_Incompatible) { if (FindConversionForRefInit(S, ICS, DeclType, DeclLoc, Init, T2, /*AllowRvalues=*/false, AllowExplicit)) return ICS; } } // -- Otherwise, the reference shall be an lvalue reference to a // non-volatile const type (i.e., cv1 shall be const), or the reference // shall be an rvalue reference. if (!isRValRef && (!T1.isConstQualified() || T1.isVolatileQualified())) { if (InitCategory.isRValue() && RefRelationship != Sema::Ref_Incompatible) ICS.setBad(BadConversionSequence::lvalue_ref_to_rvalue, Init, DeclType); return ICS; } // -- If the initializer expression // // -- is an xvalue, class prvalue, array prvalue or function // lvalue and "cv1 T1" is reference-compatible with "cv2 T2", or if (RefRelationship == Sema::Ref_Compatible && (InitCategory.isXValue() || (InitCategory.isPRValue() && (T2->isRecordType() || T2->isArrayType())) || (InitCategory.isLValue() && T2->isFunctionType()))) { // In C++11, this is always a direct binding. In C++98/03, it's a direct // binding unless we're binding to a class prvalue. // Note: Although xvalues wouldn't normally show up in C++98/03 code, we // allow the use of rvalue references in C++98/03 for the benefit of // standard library implementors; therefore, we need the xvalue check here. SetAsReferenceBinding(/*BindsDirectly=*/S.getLangOpts().CPlusPlus11 || !(InitCategory.isPRValue() || T2->isRecordType())); return ICS; } // -- has a class type (i.e., T2 is a class type), where T1 is not // reference-related to T2, and can be implicitly converted to // an xvalue, class prvalue, or function lvalue of type // "cv3 T3", where "cv1 T1" is reference-compatible with // "cv3 T3", // // then the reference is bound to the value of the initializer // expression in the first case and to the result of the conversion // in the second case (or, in either case, to an appropriate base // class subobject). if (!SuppressUserConversions && RefRelationship == Sema::Ref_Incompatible && T2->isRecordType() && S.isCompleteType(DeclLoc, T2) && FindConversionForRefInit(S, ICS, DeclType, DeclLoc, Init, T2, /*AllowRvalues=*/true, AllowExplicit)) { // In the second case, if the reference is an rvalue reference // and the second standard conversion sequence of the // user-defined conversion sequence includes an lvalue-to-rvalue // conversion, the program is ill-formed. if (ICS.isUserDefined() && isRValRef && ICS.UserDefined.After.First == ICK_Lvalue_To_Rvalue) ICS.setBad(BadConversionSequence::no_conversion, Init, DeclType); return ICS; } // A temporary of function type cannot be created; don't even try. if (T1->isFunctionType()) return ICS; // -- Otherwise, a temporary of type "cv1 T1" is created and // initialized from the initializer expression using the // rules for a non-reference copy initialization (8.5). The // reference is then bound to the temporary. If T1 is // reference-related to T2, cv1 must be the same // cv-qualification as, or greater cv-qualification than, // cv2; otherwise, the program is ill-formed. if (RefRelationship == Sema::Ref_Related) { // If cv1 == cv2 or cv1 is a greater cv-qualified than cv2, then // we would be reference-compatible or reference-compatible with // added qualification. But that wasn't the case, so the reference // initialization fails. // // Note that we only want to check address spaces and cvr-qualifiers here. // ObjC GC, lifetime and unaligned qualifiers aren't important. Qualifiers T1Quals = T1.getQualifiers(); Qualifiers T2Quals = T2.getQualifiers(); T1Quals.removeObjCGCAttr(); T1Quals.removeObjCLifetime(); T2Quals.removeObjCGCAttr(); T2Quals.removeObjCLifetime(); // MS compiler ignores __unaligned qualifier for references; do the same. T1Quals.removeUnaligned(); T2Quals.removeUnaligned(); if (!T1Quals.compatiblyIncludes(T2Quals)) return ICS; } // If at least one of the types is a class type, the types are not // related, and we aren't allowed any user conversions, the // reference binding fails. This case is important for breaking // recursion, since TryImplicitConversion below will attempt to // create a temporary through the use of a copy constructor. if (SuppressUserConversions && RefRelationship == Sema::Ref_Incompatible && (T1->isRecordType() || T2->isRecordType())) return ICS; // If T1 is reference-related to T2 and the reference is an rvalue // reference, the initializer expression shall not be an lvalue. if (RefRelationship >= Sema::Ref_Related && isRValRef && Init->Classify(S.Context).isLValue()) { ICS.setBad(BadConversionSequence::rvalue_ref_to_lvalue, Init, DeclType); return ICS; } // C++ [over.ics.ref]p2: // When a parameter of reference type is not bound directly to // an argument expression, the conversion sequence is the one // required to convert the argument expression to the // underlying type of the reference according to // 13.3.3.1. Conceptually, this conversion sequence corresponds // to copy-initializing a temporary of the underlying type with // the argument expression. Any difference in top-level // cv-qualification is subsumed by the initialization itself // and does not constitute a conversion. ICS = TryImplicitConversion(S, Init, T1, SuppressUserConversions, AllowedExplicit::None, /*InOverloadResolution=*/false, /*CStyle=*/false, /*AllowObjCWritebackConversion=*/false, /*AllowObjCConversionOnExplicit=*/false); // Of course, that's still a reference binding. if (ICS.isStandard()) { ICS.Standard.ReferenceBinding = true; ICS.Standard.IsLvalueReference = !isRValRef; ICS.Standard.BindsToFunctionLvalue = false; ICS.Standard.BindsToRvalue = true; ICS.Standard.BindsImplicitObjectArgumentWithoutRefQualifier = false; ICS.Standard.ObjCLifetimeConversionBinding = false; } else if (ICS.isUserDefined()) { const ReferenceType *LValRefType = ICS.UserDefined.ConversionFunction->getReturnType() ->getAs(); // C++ [over.ics.ref]p3: // Except for an implicit object parameter, for which see 13.3.1, a // standard conversion sequence cannot be formed if it requires [...] // binding an rvalue reference to an lvalue other than a function // lvalue. // Note that the function case is not possible here. if (isRValRef && LValRefType) { ICS.setBad(BadConversionSequence::no_conversion, Init, DeclType); return ICS; } ICS.UserDefined.After.ReferenceBinding = true; ICS.UserDefined.After.IsLvalueReference = !isRValRef; ICS.UserDefined.After.BindsToFunctionLvalue = false; ICS.UserDefined.After.BindsToRvalue = !LValRefType; ICS.UserDefined.After.BindsImplicitObjectArgumentWithoutRefQualifier = false; ICS.UserDefined.After.ObjCLifetimeConversionBinding = false; } return ICS; } static ImplicitConversionSequence TryCopyInitialization(Sema &S, Expr *From, QualType ToType, bool SuppressUserConversions, bool InOverloadResolution, bool AllowObjCWritebackConversion, bool AllowExplicit = false); /// TryListConversion - Try to copy-initialize a value of type ToType from the /// initializer list From. static ImplicitConversionSequence TryListConversion(Sema &S, InitListExpr *From, QualType ToType, bool SuppressUserConversions, bool InOverloadResolution, bool AllowObjCWritebackConversion) { // C++11 [over.ics.list]p1: // When an argument is an initializer list, it is not an expression and // special rules apply for converting it to a parameter type. ImplicitConversionSequence Result; Result.setBad(BadConversionSequence::no_conversion, From, ToType); // We need a complete type for what follows. Incomplete types can never be // initialized from init lists. if (!S.isCompleteType(From->getBeginLoc(), ToType)) return Result; // Per DR1467: // If the parameter type is a class X and the initializer list has a single // element of type cv U, where U is X or a class derived from X, the // implicit conversion sequence is the one required to convert the element // to the parameter type. // // Otherwise, if the parameter type is a character array [... ] // and the initializer list has a single element that is an // appropriately-typed string literal (8.5.2 [dcl.init.string]), the // implicit conversion sequence is the identity conversion. if (From->getNumInits() == 1) { if (ToType->isRecordType()) { QualType InitType = From->getInit(0)->getType(); if (S.Context.hasSameUnqualifiedType(InitType, ToType) || S.IsDerivedFrom(From->getBeginLoc(), InitType, ToType)) return TryCopyInitialization(S, From->getInit(0), ToType, SuppressUserConversions, InOverloadResolution, AllowObjCWritebackConversion); } if (const auto *AT = S.Context.getAsArrayType(ToType)) { if (S.IsStringInit(From->getInit(0), AT)) { InitializedEntity Entity = InitializedEntity::InitializeParameter(S.Context, ToType, /*Consumed=*/false); if (S.CanPerformCopyInitialization(Entity, From)) { Result.setStandard(); Result.Standard.setAsIdentityConversion(); Result.Standard.setFromType(ToType); Result.Standard.setAllToTypes(ToType); return Result; } } } } // C++14 [over.ics.list]p2: Otherwise, if the parameter type [...] (below). // C++11 [over.ics.list]p2: // If the parameter type is std::initializer_list or "array of X" and // all the elements can be implicitly converted to X, the implicit // conversion sequence is the worst conversion necessary to convert an // element of the list to X. // // C++14 [over.ics.list]p3: // Otherwise, if the parameter type is "array of N X", if the initializer // list has exactly N elements or if it has fewer than N elements and X is // default-constructible, and if all the elements of the initializer list // can be implicitly converted to X, the implicit conversion sequence is // the worst conversion necessary to convert an element of the list to X. // // FIXME: We're missing a lot of these checks. bool toStdInitializerList = false; QualType X; if (ToType->isArrayType()) X = S.Context.getAsArrayType(ToType)->getElementType(); else toStdInitializerList = S.isStdInitializerList(ToType, &X); if (!X.isNull()) { for (unsigned i = 0, e = From->getNumInits(); i < e; ++i) { Expr *Init = From->getInit(i); ImplicitConversionSequence ICS = TryCopyInitialization(S, Init, X, SuppressUserConversions, InOverloadResolution, AllowObjCWritebackConversion); // If a single element isn't convertible, fail. if (ICS.isBad()) { Result = ICS; break; } // Otherwise, look for the worst conversion. if (Result.isBad() || CompareImplicitConversionSequences( S, From->getBeginLoc(), ICS, Result) == ImplicitConversionSequence::Worse) Result = ICS; } // For an empty list, we won't have computed any conversion sequence. // Introduce the identity conversion sequence. if (From->getNumInits() == 0) { Result.setStandard(); Result.Standard.setAsIdentityConversion(); Result.Standard.setFromType(ToType); Result.Standard.setAllToTypes(ToType); } Result.setStdInitializerListElement(toStdInitializerList); return Result; } // C++14 [over.ics.list]p4: // C++11 [over.ics.list]p3: // Otherwise, if the parameter is a non-aggregate class X and overload // resolution chooses a single best constructor [...] the implicit // conversion sequence is a user-defined conversion sequence. If multiple // constructors are viable but none is better than the others, the // implicit conversion sequence is a user-defined conversion sequence. if (ToType->isRecordType() && !ToType->isAggregateType()) { // This function can deal with initializer lists. return TryUserDefinedConversion(S, From, ToType, SuppressUserConversions, AllowedExplicit::None, InOverloadResolution, /*CStyle=*/false, AllowObjCWritebackConversion, /*AllowObjCConversionOnExplicit=*/false); } // C++14 [over.ics.list]p5: // C++11 [over.ics.list]p4: // Otherwise, if the parameter has an aggregate type which can be // initialized from the initializer list [...] the implicit conversion // sequence is a user-defined conversion sequence. if (ToType->isAggregateType()) { // Type is an aggregate, argument is an init list. At this point it comes // down to checking whether the initialization works. // FIXME: Find out whether this parameter is consumed or not. InitializedEntity Entity = InitializedEntity::InitializeParameter(S.Context, ToType, /*Consumed=*/false); if (S.CanPerformAggregateInitializationForOverloadResolution(Entity, From)) { Result.setUserDefined(); Result.UserDefined.Before.setAsIdentityConversion(); // Initializer lists don't have a type. Result.UserDefined.Before.setFromType(QualType()); Result.UserDefined.Before.setAllToTypes(QualType()); Result.UserDefined.After.setAsIdentityConversion(); Result.UserDefined.After.setFromType(ToType); Result.UserDefined.After.setAllToTypes(ToType); Result.UserDefined.ConversionFunction = nullptr; } return Result; } // C++14 [over.ics.list]p6: // C++11 [over.ics.list]p5: // Otherwise, if the parameter is a reference, see 13.3.3.1.4. if (ToType->isReferenceType()) { // The standard is notoriously unclear here, since 13.3.3.1.4 doesn't // mention initializer lists in any way. So we go by what list- // initialization would do and try to extrapolate from that. QualType T1 = ToType->castAs()->getPointeeType(); // If the initializer list has a single element that is reference-related // to the parameter type, we initialize the reference from that. if (From->getNumInits() == 1) { Expr *Init = From->getInit(0); QualType T2 = Init->getType(); // If the initializer is the address of an overloaded function, try // to resolve the overloaded function. If all goes well, T2 is the // type of the resulting function. if (S.Context.getCanonicalType(T2) == S.Context.OverloadTy) { DeclAccessPair Found; if (FunctionDecl *Fn = S.ResolveAddressOfOverloadedFunction( Init, ToType, false, Found)) T2 = Fn->getType(); } // Compute some basic properties of the types and the initializer. Sema::ReferenceCompareResult RefRelationship = S.CompareReferenceRelationship(From->getBeginLoc(), T1, T2); if (RefRelationship >= Sema::Ref_Related) { return TryReferenceInit(S, Init, ToType, /*FIXME*/ From->getBeginLoc(), SuppressUserConversions, /*AllowExplicit=*/false); } } // Otherwise, we bind the reference to a temporary created from the // initializer list. Result = TryListConversion(S, From, T1, SuppressUserConversions, InOverloadResolution, AllowObjCWritebackConversion); if (Result.isFailure()) return Result; assert(!Result.isEllipsis() && "Sub-initialization cannot result in ellipsis conversion."); // Can we even bind to a temporary? if (ToType->isRValueReferenceType() || (T1.isConstQualified() && !T1.isVolatileQualified())) { StandardConversionSequence &SCS = Result.isStandard() ? Result.Standard : Result.UserDefined.After; SCS.ReferenceBinding = true; SCS.IsLvalueReference = ToType->isLValueReferenceType(); SCS.BindsToRvalue = true; SCS.BindsToFunctionLvalue = false; SCS.BindsImplicitObjectArgumentWithoutRefQualifier = false; SCS.ObjCLifetimeConversionBinding = false; } else Result.setBad(BadConversionSequence::lvalue_ref_to_rvalue, From, ToType); return Result; } // C++14 [over.ics.list]p7: // C++11 [over.ics.list]p6: // Otherwise, if the parameter type is not a class: if (!ToType->isRecordType()) { // - if the initializer list has one element that is not itself an // initializer list, the implicit conversion sequence is the one // required to convert the element to the parameter type. unsigned NumInits = From->getNumInits(); if (NumInits == 1 && !isa(From->getInit(0))) Result = TryCopyInitialization(S, From->getInit(0), ToType, SuppressUserConversions, InOverloadResolution, AllowObjCWritebackConversion); // - if the initializer list has no elements, the implicit conversion // sequence is the identity conversion. else if (NumInits == 0) { Result.setStandard(); Result.Standard.setAsIdentityConversion(); Result.Standard.setFromType(ToType); Result.Standard.setAllToTypes(ToType); } return Result; } // C++14 [over.ics.list]p8: // C++11 [over.ics.list]p7: // In all cases other than those enumerated above, no conversion is possible return Result; } /// TryCopyInitialization - Try to copy-initialize a value of type /// ToType from the expression From. Return the implicit conversion /// sequence required to pass this argument, which may be a bad /// conversion sequence (meaning that the argument cannot be passed to /// a parameter of this type). If @p SuppressUserConversions, then we /// do not permit any user-defined conversion sequences. static ImplicitConversionSequence TryCopyInitialization(Sema &S, Expr *From, QualType ToType, bool SuppressUserConversions, bool InOverloadResolution, bool AllowObjCWritebackConversion, bool AllowExplicit) { if (InitListExpr *FromInitList = dyn_cast(From)) return TryListConversion(S, FromInitList, ToType, SuppressUserConversions, InOverloadResolution,AllowObjCWritebackConversion); if (ToType->isReferenceType()) return TryReferenceInit(S, From, ToType, /*FIXME:*/ From->getBeginLoc(), SuppressUserConversions, AllowExplicit); return TryImplicitConversion(S, From, ToType, SuppressUserConversions, AllowedExplicit::None, InOverloadResolution, /*CStyle=*/false, AllowObjCWritebackConversion, /*AllowObjCConversionOnExplicit=*/false); } static bool TryCopyInitialization(const CanQualType FromQTy, const CanQualType ToQTy, Sema &S, SourceLocation Loc, ExprValueKind FromVK) { OpaqueValueExpr TmpExpr(Loc, FromQTy, FromVK); ImplicitConversionSequence ICS = TryCopyInitialization(S, &TmpExpr, ToQTy, true, true, false); return !ICS.isBad(); } /// TryObjectArgumentInitialization - Try to initialize the object /// parameter of the given member function (@c Method) from the /// expression @p From. static ImplicitConversionSequence TryObjectArgumentInitialization(Sema &S, SourceLocation Loc, QualType FromType, Expr::Classification FromClassification, CXXMethodDecl *Method, CXXRecordDecl *ActingContext) { QualType ClassType = S.Context.getTypeDeclType(ActingContext); // [class.dtor]p2: A destructor can be invoked for a const, volatile or // const volatile object. Qualifiers Quals = Method->getMethodQualifiers(); if (isa(Method)) { Quals.addConst(); Quals.addVolatile(); } QualType ImplicitParamType = S.Context.getQualifiedType(ClassType, Quals); // Set up the conversion sequence as a "bad" conversion, to allow us // to exit early. ImplicitConversionSequence ICS; // We need to have an object of class type. if (const PointerType *PT = FromType->getAs()) { FromType = PT->getPointeeType(); // When we had a pointer, it's implicitly dereferenced, so we // better have an lvalue. assert(FromClassification.isLValue()); } assert(FromType->isRecordType()); // C++0x [over.match.funcs]p4: // For non-static member functions, the type of the implicit object // parameter is // // - "lvalue reference to cv X" for functions declared without a // ref-qualifier or with the & ref-qualifier // - "rvalue reference to cv X" for functions declared with the && // ref-qualifier // // where X is the class of which the function is a member and cv is the // cv-qualification on the member function declaration. // // However, when finding an implicit conversion sequence for the argument, we // are not allowed to perform user-defined conversions // (C++ [over.match.funcs]p5). We perform a simplified version of // reference binding here, that allows class rvalues to bind to // non-constant references. // First check the qualifiers. QualType FromTypeCanon = S.Context.getCanonicalType(FromType); if (ImplicitParamType.getCVRQualifiers() != FromTypeCanon.getLocalCVRQualifiers() && !ImplicitParamType.isAtLeastAsQualifiedAs(FromTypeCanon)) { ICS.setBad(BadConversionSequence::bad_qualifiers, FromType, ImplicitParamType); return ICS; } if (FromTypeCanon.hasAddressSpace()) { Qualifiers QualsImplicitParamType = ImplicitParamType.getQualifiers(); Qualifiers QualsFromType = FromTypeCanon.getQualifiers(); if (!QualsImplicitParamType.isAddressSpaceSupersetOf(QualsFromType)) { ICS.setBad(BadConversionSequence::bad_qualifiers, FromType, ImplicitParamType); return ICS; } } // Check that we have either the same type or a derived type. It // affects the conversion rank. QualType ClassTypeCanon = S.Context.getCanonicalType(ClassType); ImplicitConversionKind SecondKind; if (ClassTypeCanon == FromTypeCanon.getLocalUnqualifiedType()) { SecondKind = ICK_Identity; } else if (S.IsDerivedFrom(Loc, FromType, ClassType)) SecondKind = ICK_Derived_To_Base; else { ICS.setBad(BadConversionSequence::unrelated_class, FromType, ImplicitParamType); return ICS; } // Check the ref-qualifier. switch (Method->getRefQualifier()) { case RQ_None: // Do nothing; we don't care about lvalueness or rvalueness. break; case RQ_LValue: if (!FromClassification.isLValue() && !Quals.hasOnlyConst()) { // non-const lvalue reference cannot bind to an rvalue ICS.setBad(BadConversionSequence::lvalue_ref_to_rvalue, FromType, ImplicitParamType); return ICS; } break; case RQ_RValue: if (!FromClassification.isRValue()) { // rvalue reference cannot bind to an lvalue ICS.setBad(BadConversionSequence::rvalue_ref_to_lvalue, FromType, ImplicitParamType); return ICS; } break; } // Success. Mark this as a reference binding. ICS.setStandard(); ICS.Standard.setAsIdentityConversion(); ICS.Standard.Second = SecondKind; ICS.Standard.setFromType(FromType); ICS.Standard.setAllToTypes(ImplicitParamType); ICS.Standard.ReferenceBinding = true; ICS.Standard.DirectBinding = true; ICS.Standard.IsLvalueReference = Method->getRefQualifier() != RQ_RValue; ICS.Standard.BindsToFunctionLvalue = false; ICS.Standard.BindsToRvalue = FromClassification.isRValue(); ICS.Standard.BindsImplicitObjectArgumentWithoutRefQualifier = (Method->getRefQualifier() == RQ_None); return ICS; } /// PerformObjectArgumentInitialization - Perform initialization of /// the implicit object parameter for the given Method with the given /// expression. ExprResult Sema::PerformObjectArgumentInitialization(Expr *From, NestedNameSpecifier *Qualifier, NamedDecl *FoundDecl, CXXMethodDecl *Method) { QualType FromRecordType, DestType; QualType ImplicitParamRecordType = Method->getThisType()->castAs()->getPointeeType(); Expr::Classification FromClassification; if (const PointerType *PT = From->getType()->getAs()) { FromRecordType = PT->getPointeeType(); DestType = Method->getThisType(); FromClassification = Expr::Classification::makeSimpleLValue(); } else { FromRecordType = From->getType(); DestType = ImplicitParamRecordType; FromClassification = From->Classify(Context); // When performing member access on an rvalue, materialize a temporary. if (From->isRValue()) { From = CreateMaterializeTemporaryExpr(FromRecordType, From, Method->getRefQualifier() != RefQualifierKind::RQ_RValue); } } // Note that we always use the true parent context when performing // the actual argument initialization. ImplicitConversionSequence ICS = TryObjectArgumentInitialization( *this, From->getBeginLoc(), From->getType(), FromClassification, Method, Method->getParent()); if (ICS.isBad()) { switch (ICS.Bad.Kind) { case BadConversionSequence::bad_qualifiers: { Qualifiers FromQs = FromRecordType.getQualifiers(); Qualifiers ToQs = DestType.getQualifiers(); unsigned CVR = FromQs.getCVRQualifiers() & ~ToQs.getCVRQualifiers(); if (CVR) { Diag(From->getBeginLoc(), diag::err_member_function_call_bad_cvr) << Method->getDeclName() << FromRecordType << (CVR - 1) << From->getSourceRange(); Diag(Method->getLocation(), diag::note_previous_decl) << Method->getDeclName(); return ExprError(); } break; } case BadConversionSequence::lvalue_ref_to_rvalue: case BadConversionSequence::rvalue_ref_to_lvalue: { bool IsRValueQualified = Method->getRefQualifier() == RefQualifierKind::RQ_RValue; Diag(From->getBeginLoc(), diag::err_member_function_call_bad_ref) << Method->getDeclName() << FromClassification.isRValue() << IsRValueQualified; Diag(Method->getLocation(), diag::note_previous_decl) << Method->getDeclName(); return ExprError(); } case BadConversionSequence::no_conversion: case BadConversionSequence::unrelated_class: break; } return Diag(From->getBeginLoc(), diag::err_member_function_call_bad_type) << ImplicitParamRecordType << FromRecordType << From->getSourceRange(); } if (ICS.Standard.Second == ICK_Derived_To_Base) { ExprResult FromRes = PerformObjectMemberConversion(From, Qualifier, FoundDecl, Method); if (FromRes.isInvalid()) return ExprError(); From = FromRes.get(); } if (!Context.hasSameType(From->getType(), DestType)) { CastKind CK; QualType PteeTy = DestType->getPointeeType(); LangAS DestAS = PteeTy.isNull() ? DestType.getAddressSpace() : PteeTy.getAddressSpace(); if (FromRecordType.getAddressSpace() != DestAS) CK = CK_AddressSpaceConversion; else CK = CK_NoOp; From = ImpCastExprToType(From, DestType, CK, From->getValueKind()).get(); } return From; } /// TryContextuallyConvertToBool - Attempt to contextually convert the /// expression From to bool (C++0x [conv]p3). static ImplicitConversionSequence TryContextuallyConvertToBool(Sema &S, Expr *From) { // C++ [dcl.init]/17.8: // - Otherwise, if the initialization is direct-initialization, the source // type is std::nullptr_t, and the destination type is bool, the initial // value of the object being initialized is false. if (From->getType()->isNullPtrType()) return ImplicitConversionSequence::getNullptrToBool(From->getType(), S.Context.BoolTy, From->isGLValue()); // All other direct-initialization of bool is equivalent to an implicit // conversion to bool in which explicit conversions are permitted. return TryImplicitConversion(S, From, S.Context.BoolTy, /*SuppressUserConversions=*/false, AllowedExplicit::Conversions, /*InOverloadResolution=*/false, /*CStyle=*/false, /*AllowObjCWritebackConversion=*/false, /*AllowObjCConversionOnExplicit=*/false); } /// PerformContextuallyConvertToBool - Perform a contextual conversion /// of the expression From to bool (C++0x [conv]p3). ExprResult Sema::PerformContextuallyConvertToBool(Expr *From) { if (checkPlaceholderForOverload(*this, From)) return ExprError(); ImplicitConversionSequence ICS = TryContextuallyConvertToBool(*this, From); if (!ICS.isBad()) return PerformImplicitConversion(From, Context.BoolTy, ICS, AA_Converting); if (!DiagnoseMultipleUserDefinedConversion(From, Context.BoolTy)) return Diag(From->getBeginLoc(), diag::err_typecheck_bool_condition) << From->getType() << From->getSourceRange(); return ExprError(); } /// Check that the specified conversion is permitted in a converted constant /// expression, according to C++11 [expr.const]p3. Return true if the conversion /// is acceptable. static bool CheckConvertedConstantConversions(Sema &S, StandardConversionSequence &SCS) { // Since we know that the target type is an integral or unscoped enumeration // type, most conversion kinds are impossible. All possible First and Third // conversions are fine. switch (SCS.Second) { case ICK_Identity: case ICK_Integral_Promotion: case ICK_Integral_Conversion: // Narrowing conversions are checked elsewhere. case ICK_Zero_Queue_Conversion: return true; case ICK_Boolean_Conversion: // Conversion from an integral or unscoped enumeration type to bool is // classified as ICK_Boolean_Conversion, but it's also arguably an integral // conversion, so we allow it in a converted constant expression. // // FIXME: Per core issue 1407, we should not allow this, but that breaks // a lot of popular code. We should at least add a warning for this // (non-conforming) extension. return SCS.getFromType()->isIntegralOrUnscopedEnumerationType() && SCS.getToType(2)->isBooleanType(); case ICK_Pointer_Conversion: case ICK_Pointer_Member: // C++1z: null pointer conversions and null member pointer conversions are // only permitted if the source type is std::nullptr_t. return SCS.getFromType()->isNullPtrType(); case ICK_Floating_Promotion: case ICK_Complex_Promotion: case ICK_Floating_Conversion: case ICK_Complex_Conversion: case ICK_Floating_Integral: case ICK_Compatible_Conversion: case ICK_Derived_To_Base: case ICK_Vector_Conversion: case ICK_SVE_Vector_Conversion: case ICK_Vector_Splat: case ICK_Complex_Real: case ICK_Block_Pointer_Conversion: case ICK_TransparentUnionConversion: case ICK_Writeback_Conversion: case ICK_Zero_Event_Conversion: case ICK_C_Only_Conversion: case ICK_Incompatible_Pointer_Conversion: return false; case ICK_Lvalue_To_Rvalue: case ICK_Array_To_Pointer: case ICK_Function_To_Pointer: llvm_unreachable("found a first conversion kind in Second"); case ICK_Function_Conversion: case ICK_Qualification: llvm_unreachable("found a third conversion kind in Second"); case ICK_Num_Conversion_Kinds: break; } llvm_unreachable("unknown conversion kind"); } /// CheckConvertedConstantExpression - Check that the expression From is a /// converted constant expression of type T, perform the conversion and produce /// the converted expression, per C++11 [expr.const]p3. static ExprResult CheckConvertedConstantExpression(Sema &S, Expr *From, QualType T, APValue &Value, Sema::CCEKind CCE, bool RequireInt, NamedDecl *Dest) { assert(S.getLangOpts().CPlusPlus11 && "converted constant expression outside C++11"); if (checkPlaceholderForOverload(S, From)) return ExprError(); // C++1z [expr.const]p3: // A converted constant expression of type T is an expression, // implicitly converted to type T, where the converted // expression is a constant expression and the implicit conversion // sequence contains only [... list of conversions ...]. // C++1z [stmt.if]p2: // If the if statement is of the form if constexpr, the value of the // condition shall be a contextually converted constant expression of type // bool. ImplicitConversionSequence ICS = CCE == Sema::CCEK_ConstexprIf || CCE == Sema::CCEK_ExplicitBool ? TryContextuallyConvertToBool(S, From) : TryCopyInitialization(S, From, T, /*SuppressUserConversions=*/false, /*InOverloadResolution=*/false, /*AllowObjCWritebackConversion=*/false, /*AllowExplicit=*/false); StandardConversionSequence *SCS = nullptr; switch (ICS.getKind()) { case ImplicitConversionSequence::StandardConversion: SCS = &ICS.Standard; break; case ImplicitConversionSequence::UserDefinedConversion: if (T->isRecordType()) SCS = &ICS.UserDefined.Before; else SCS = &ICS.UserDefined.After; break; case ImplicitConversionSequence::AmbiguousConversion: case ImplicitConversionSequence::BadConversion: if (!S.DiagnoseMultipleUserDefinedConversion(From, T)) return S.Diag(From->getBeginLoc(), diag::err_typecheck_converted_constant_expression) << From->getType() << From->getSourceRange() << T; return ExprError(); case ImplicitConversionSequence::EllipsisConversion: llvm_unreachable("ellipsis conversion in converted constant expression"); } // Check that we would only use permitted conversions. if (!CheckConvertedConstantConversions(S, *SCS)) { return S.Diag(From->getBeginLoc(), diag::err_typecheck_converted_constant_expression_disallowed) << From->getType() << From->getSourceRange() << T; } // [...] and where the reference binding (if any) binds directly. if (SCS->ReferenceBinding && !SCS->DirectBinding) { return S.Diag(From->getBeginLoc(), diag::err_typecheck_converted_constant_expression_indirect) << From->getType() << From->getSourceRange() << T; } // Usually we can simply apply the ImplicitConversionSequence we formed // earlier, but that's not guaranteed to work when initializing an object of // class type. ExprResult Result; if (T->isRecordType()) { assert(CCE == Sema::CCEK_TemplateArg && "unexpected class type converted constant expr"); Result = S.PerformCopyInitialization( InitializedEntity::InitializeTemplateParameter( T, cast(Dest)), SourceLocation(), From); } else { Result = S.PerformImplicitConversion(From, T, ICS, Sema::AA_Converting); } if (Result.isInvalid()) return Result; // C++2a [intro.execution]p5: // A full-expression is [...] a constant-expression [...] Result = S.ActOnFinishFullExpr(Result.get(), From->getExprLoc(), /*DiscardedValue=*/false, /*IsConstexpr=*/true); if (Result.isInvalid()) return Result; // Check for a narrowing implicit conversion. bool ReturnPreNarrowingValue = false; APValue PreNarrowingValue; QualType PreNarrowingType; switch (SCS->getNarrowingKind(S.Context, Result.get(), PreNarrowingValue, PreNarrowingType)) { case NK_Dependent_Narrowing: // Implicit conversion to a narrower type, but the expression is // value-dependent so we can't tell whether it's actually narrowing. case NK_Variable_Narrowing: // Implicit conversion to a narrower type, and the value is not a constant // expression. We'll diagnose this in a moment. case NK_Not_Narrowing: break; case NK_Constant_Narrowing: if (CCE == Sema::CCEK_ArrayBound && PreNarrowingType->isIntegralOrEnumerationType() && PreNarrowingValue.isInt()) { // Don't diagnose array bound narrowing here; we produce more precise // errors by allowing the un-narrowed value through. ReturnPreNarrowingValue = true; break; } S.Diag(From->getBeginLoc(), diag::ext_cce_narrowing) << CCE << /*Constant*/ 1 << PreNarrowingValue.getAsString(S.Context, PreNarrowingType) << T; break; case NK_Type_Narrowing: // FIXME: It would be better to diagnose that the expression is not a // constant expression. S.Diag(From->getBeginLoc(), diag::ext_cce_narrowing) << CCE << /*Constant*/ 0 << From->getType() << T; break; } if (Result.get()->isValueDependent()) { Value = APValue(); return Result; } // Check the expression is a constant expression. SmallVector Notes; Expr::EvalResult Eval; Eval.Diag = &Notes; ConstantExprKind Kind; if (CCE == Sema::CCEK_TemplateArg && T->isRecordType()) Kind = ConstantExprKind::ClassTemplateArgument; else if (CCE == Sema::CCEK_TemplateArg) Kind = ConstantExprKind::NonClassTemplateArgument; else Kind = ConstantExprKind::Normal; if (!Result.get()->EvaluateAsConstantExpr(Eval, S.Context, Kind) || (RequireInt && !Eval.Val.isInt())) { // The expression can't be folded, so we can't keep it at this position in // the AST. Result = ExprError(); } else { Value = Eval.Val; if (Notes.empty()) { // It's a constant expression. Expr *E = ConstantExpr::Create(S.Context, Result.get(), Value); if (ReturnPreNarrowingValue) Value = std::move(PreNarrowingValue); return E; } } // It's not a constant expression. Produce an appropriate diagnostic. if (Notes.size() == 1 && Notes[0].second.getDiagID() == diag::note_invalid_subexpr_in_const_expr) { S.Diag(Notes[0].first, diag::err_expr_not_cce) << CCE; } else if (!Notes.empty() && Notes[0].second.getDiagID() == diag::note_constexpr_invalid_template_arg) { Notes[0].second.setDiagID(diag::err_constexpr_invalid_template_arg); for (unsigned I = 0; I < Notes.size(); ++I) S.Diag(Notes[I].first, Notes[I].second); } else { S.Diag(From->getBeginLoc(), diag::err_expr_not_cce) << CCE << From->getSourceRange(); for (unsigned I = 0; I < Notes.size(); ++I) S.Diag(Notes[I].first, Notes[I].second); } return ExprError(); } ExprResult Sema::CheckConvertedConstantExpression(Expr *From, QualType T, APValue &Value, CCEKind CCE, NamedDecl *Dest) { return ::CheckConvertedConstantExpression(*this, From, T, Value, CCE, false, Dest); } ExprResult Sema::CheckConvertedConstantExpression(Expr *From, QualType T, llvm::APSInt &Value, CCEKind CCE) { assert(T->isIntegralOrEnumerationType() && "unexpected converted const type"); APValue V; auto R = ::CheckConvertedConstantExpression(*this, From, T, V, CCE, true, /*Dest=*/nullptr); if (!R.isInvalid() && !R.get()->isValueDependent()) Value = V.getInt(); return R; } /// dropPointerConversions - If the given standard conversion sequence /// involves any pointer conversions, remove them. This may change /// the result type of the conversion sequence. static void dropPointerConversion(StandardConversionSequence &SCS) { if (SCS.Second == ICK_Pointer_Conversion) { SCS.Second = ICK_Identity; SCS.Third = ICK_Identity; SCS.ToTypePtrs[2] = SCS.ToTypePtrs[1] = SCS.ToTypePtrs[0]; } } /// TryContextuallyConvertToObjCPointer - Attempt to contextually /// convert the expression From to an Objective-C pointer type. static ImplicitConversionSequence TryContextuallyConvertToObjCPointer(Sema &S, Expr *From) { // Do an implicit conversion to 'id'. QualType Ty = S.Context.getObjCIdType(); ImplicitConversionSequence ICS = TryImplicitConversion(S, From, Ty, // FIXME: Are these flags correct? /*SuppressUserConversions=*/false, AllowedExplicit::Conversions, /*InOverloadResolution=*/false, /*CStyle=*/false, /*AllowObjCWritebackConversion=*/false, /*AllowObjCConversionOnExplicit=*/true); // Strip off any final conversions to 'id'. switch (ICS.getKind()) { case ImplicitConversionSequence::BadConversion: case ImplicitConversionSequence::AmbiguousConversion: case ImplicitConversionSequence::EllipsisConversion: break; case ImplicitConversionSequence::UserDefinedConversion: dropPointerConversion(ICS.UserDefined.After); break; case ImplicitConversionSequence::StandardConversion: dropPointerConversion(ICS.Standard); break; } return ICS; } /// PerformContextuallyConvertToObjCPointer - Perform a contextual /// conversion of the expression From to an Objective-C pointer type. /// Returns a valid but null ExprResult if no conversion sequence exists. ExprResult Sema::PerformContextuallyConvertToObjCPointer(Expr *From) { if (checkPlaceholderForOverload(*this, From)) return ExprError(); QualType Ty = Context.getObjCIdType(); ImplicitConversionSequence ICS = TryContextuallyConvertToObjCPointer(*this, From); if (!ICS.isBad()) return PerformImplicitConversion(From, Ty, ICS, AA_Converting); return ExprResult(); } /// Determine whether the provided type is an integral type, or an enumeration /// type of a permitted flavor. bool Sema::ICEConvertDiagnoser::match(QualType T) { return AllowScopedEnumerations ? T->isIntegralOrEnumerationType() : T->isIntegralOrUnscopedEnumerationType(); } static ExprResult diagnoseAmbiguousConversion(Sema &SemaRef, SourceLocation Loc, Expr *From, Sema::ContextualImplicitConverter &Converter, QualType T, UnresolvedSetImpl &ViableConversions) { if (Converter.Suppress) return ExprError(); Converter.diagnoseAmbiguous(SemaRef, Loc, T) << From->getSourceRange(); for (unsigned I = 0, N = ViableConversions.size(); I != N; ++I) { CXXConversionDecl *Conv = cast(ViableConversions[I]->getUnderlyingDecl()); QualType ConvTy = Conv->getConversionType().getNonReferenceType(); Converter.noteAmbiguous(SemaRef, Conv, ConvTy); } return From; } static bool diagnoseNoViableConversion(Sema &SemaRef, SourceLocation Loc, Expr *&From, Sema::ContextualImplicitConverter &Converter, QualType T, bool HadMultipleCandidates, UnresolvedSetImpl &ExplicitConversions) { if (ExplicitConversions.size() == 1 && !Converter.Suppress) { DeclAccessPair Found = ExplicitConversions[0]; CXXConversionDecl *Conversion = cast(Found->getUnderlyingDecl()); // The user probably meant to invoke the given explicit // conversion; use it. QualType ConvTy = Conversion->getConversionType().getNonReferenceType(); std::string TypeStr; ConvTy.getAsStringInternal(TypeStr, SemaRef.getPrintingPolicy()); Converter.diagnoseExplicitConv(SemaRef, Loc, T, ConvTy) << FixItHint::CreateInsertion(From->getBeginLoc(), "static_cast<" + TypeStr + ">(") << FixItHint::CreateInsertion( SemaRef.getLocForEndOfToken(From->getEndLoc()), ")"); Converter.noteExplicitConv(SemaRef, Conversion, ConvTy); // If we aren't in a SFINAE context, build a call to the // explicit conversion function. if (SemaRef.isSFINAEContext()) return true; SemaRef.CheckMemberOperatorAccess(From->getExprLoc(), From, nullptr, Found); ExprResult Result = SemaRef.BuildCXXMemberCallExpr(From, Found, Conversion, HadMultipleCandidates); if (Result.isInvalid()) return true; // Record usage of conversion in an implicit cast. From = ImplicitCastExpr::Create(SemaRef.Context, Result.get()->getType(), CK_UserDefinedConversion, Result.get(), nullptr, Result.get()->getValueKind(), SemaRef.CurFPFeatureOverrides()); } return false; } static bool recordConversion(Sema &SemaRef, SourceLocation Loc, Expr *&From, Sema::ContextualImplicitConverter &Converter, QualType T, bool HadMultipleCandidates, DeclAccessPair &Found) { CXXConversionDecl *Conversion = cast(Found->getUnderlyingDecl()); SemaRef.CheckMemberOperatorAccess(From->getExprLoc(), From, nullptr, Found); QualType ToType = Conversion->getConversionType().getNonReferenceType(); if (!Converter.SuppressConversion) { if (SemaRef.isSFINAEContext()) return true; Converter.diagnoseConversion(SemaRef, Loc, T, ToType) << From->getSourceRange(); } ExprResult Result = SemaRef.BuildCXXMemberCallExpr(From, Found, Conversion, HadMultipleCandidates); if (Result.isInvalid()) return true; // Record usage of conversion in an implicit cast. From = ImplicitCastExpr::Create(SemaRef.Context, Result.get()->getType(), CK_UserDefinedConversion, Result.get(), nullptr, Result.get()->getValueKind(), SemaRef.CurFPFeatureOverrides()); return false; } static ExprResult finishContextualImplicitConversion( Sema &SemaRef, SourceLocation Loc, Expr *From, Sema::ContextualImplicitConverter &Converter) { if (!Converter.match(From->getType()) && !Converter.Suppress) Converter.diagnoseNoMatch(SemaRef, Loc, From->getType()) << From->getSourceRange(); return SemaRef.DefaultLvalueConversion(From); } static void collectViableConversionCandidates(Sema &SemaRef, Expr *From, QualType ToType, UnresolvedSetImpl &ViableConversions, OverloadCandidateSet &CandidateSet) { for (unsigned I = 0, N = ViableConversions.size(); I != N; ++I) { DeclAccessPair FoundDecl = ViableConversions[I]; NamedDecl *D = FoundDecl.getDecl(); CXXRecordDecl *ActingContext = cast(D->getDeclContext()); if (isa(D)) D = cast(D)->getTargetDecl(); CXXConversionDecl *Conv; FunctionTemplateDecl *ConvTemplate; if ((ConvTemplate = dyn_cast(D))) Conv = cast(ConvTemplate->getTemplatedDecl()); else Conv = cast(D); if (ConvTemplate) SemaRef.AddTemplateConversionCandidate( ConvTemplate, FoundDecl, ActingContext, From, ToType, CandidateSet, /*AllowObjCConversionOnExplicit=*/false, /*AllowExplicit*/ true); else SemaRef.AddConversionCandidate(Conv, FoundDecl, ActingContext, From, ToType, CandidateSet, /*AllowObjCConversionOnExplicit=*/false, /*AllowExplicit*/ true); } } /// Attempt to convert the given expression to a type which is accepted /// by the given converter. /// /// This routine will attempt to convert an expression of class type to a /// type accepted by the specified converter. In C++11 and before, the class /// must have a single non-explicit conversion function converting to a matching /// type. In C++1y, there can be multiple such conversion functions, but only /// one target type. /// /// \param Loc The source location of the construct that requires the /// conversion. /// /// \param From The expression we're converting from. /// /// \param Converter Used to control and diagnose the conversion process. /// /// \returns The expression, converted to an integral or enumeration type if /// successful. ExprResult Sema::PerformContextualImplicitConversion( SourceLocation Loc, Expr *From, ContextualImplicitConverter &Converter) { // We can't perform any more checking for type-dependent expressions. if (From->isTypeDependent()) return From; // Process placeholders immediately. if (From->hasPlaceholderType()) { ExprResult result = CheckPlaceholderExpr(From); if (result.isInvalid()) return result; From = result.get(); } // If the expression already has a matching type, we're golden. QualType T = From->getType(); if (Converter.match(T)) return DefaultLvalueConversion(From); // FIXME: Check for missing '()' if T is a function type? // We can only perform contextual implicit conversions on objects of class // type. const RecordType *RecordTy = T->getAs(); if (!RecordTy || !getLangOpts().CPlusPlus) { if (!Converter.Suppress) Converter.diagnoseNoMatch(*this, Loc, T) << From->getSourceRange(); return From; } // We must have a complete class type. struct TypeDiagnoserPartialDiag : TypeDiagnoser { ContextualImplicitConverter &Converter; Expr *From; TypeDiagnoserPartialDiag(ContextualImplicitConverter &Converter, Expr *From) : Converter(Converter), From(From) {} void diagnose(Sema &S, SourceLocation Loc, QualType T) override { Converter.diagnoseIncomplete(S, Loc, T) << From->getSourceRange(); } } IncompleteDiagnoser(Converter, From); if (Converter.Suppress ? !isCompleteType(Loc, T) : RequireCompleteType(Loc, T, IncompleteDiagnoser)) return From; // Look for a conversion to an integral or enumeration type. UnresolvedSet<4> ViableConversions; // These are *potentially* viable in C++1y. UnresolvedSet<4> ExplicitConversions; const auto &Conversions = cast(RecordTy->getDecl())->getVisibleConversionFunctions(); bool HadMultipleCandidates = (std::distance(Conversions.begin(), Conversions.end()) > 1); // To check that there is only one target type, in C++1y: QualType ToType; bool HasUniqueTargetType = true; // Collect explicit or viable (potentially in C++1y) conversions. for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) { NamedDecl *D = (*I)->getUnderlyingDecl(); CXXConversionDecl *Conversion; FunctionTemplateDecl *ConvTemplate = dyn_cast(D); if (ConvTemplate) { if (getLangOpts().CPlusPlus14) Conversion = cast(ConvTemplate->getTemplatedDecl()); else continue; // C++11 does not consider conversion operator templates(?). } else Conversion = cast(D); assert((!ConvTemplate || getLangOpts().CPlusPlus14) && "Conversion operator templates are considered potentially " "viable in C++1y"); QualType CurToType = Conversion->getConversionType().getNonReferenceType(); if (Converter.match(CurToType) || ConvTemplate) { if (Conversion->isExplicit()) { // FIXME: For C++1y, do we need this restriction? // cf. diagnoseNoViableConversion() if (!ConvTemplate) ExplicitConversions.addDecl(I.getDecl(), I.getAccess()); } else { if (!ConvTemplate && getLangOpts().CPlusPlus14) { if (ToType.isNull()) ToType = CurToType.getUnqualifiedType(); else if (HasUniqueTargetType && (CurToType.getUnqualifiedType() != ToType)) HasUniqueTargetType = false; } ViableConversions.addDecl(I.getDecl(), I.getAccess()); } } } if (getLangOpts().CPlusPlus14) { // C++1y [conv]p6: // ... An expression e of class type E appearing in such a context // is said to be contextually implicitly converted to a specified // type T and is well-formed if and only if e can be implicitly // converted to a type T that is determined as follows: E is searched // for conversion functions whose return type is cv T or reference to // cv T such that T is allowed by the context. There shall be // exactly one such T. // If no unique T is found: if (ToType.isNull()) { if (diagnoseNoViableConversion(*this, Loc, From, Converter, T, HadMultipleCandidates, ExplicitConversions)) return ExprError(); return finishContextualImplicitConversion(*this, Loc, From, Converter); } // If more than one unique Ts are found: if (!HasUniqueTargetType) return diagnoseAmbiguousConversion(*this, Loc, From, Converter, T, ViableConversions); // If one unique T is found: // First, build a candidate set from the previously recorded // potentially viable conversions. OverloadCandidateSet CandidateSet(Loc, OverloadCandidateSet::CSK_Normal); collectViableConversionCandidates(*this, From, ToType, ViableConversions, CandidateSet); // Then, perform overload resolution over the candidate set. OverloadCandidateSet::iterator Best; switch (CandidateSet.BestViableFunction(*this, Loc, Best)) { case OR_Success: { // Apply this conversion. DeclAccessPair Found = DeclAccessPair::make(Best->Function, Best->FoundDecl.getAccess()); if (recordConversion(*this, Loc, From, Converter, T, HadMultipleCandidates, Found)) return ExprError(); break; } case OR_Ambiguous: return diagnoseAmbiguousConversion(*this, Loc, From, Converter, T, ViableConversions); case OR_No_Viable_Function: if (diagnoseNoViableConversion(*this, Loc, From, Converter, T, HadMultipleCandidates, ExplicitConversions)) return ExprError(); LLVM_FALLTHROUGH; case OR_Deleted: // We'll complain below about a non-integral condition type. break; } } else { switch (ViableConversions.size()) { case 0: { if (diagnoseNoViableConversion(*this, Loc, From, Converter, T, HadMultipleCandidates, ExplicitConversions)) return ExprError(); // We'll complain below about a non-integral condition type. break; } case 1: { // Apply this conversion. DeclAccessPair Found = ViableConversions[0]; if (recordConversion(*this, Loc, From, Converter, T, HadMultipleCandidates, Found)) return ExprError(); break; } default: return diagnoseAmbiguousConversion(*this, Loc, From, Converter, T, ViableConversions); } } return finishContextualImplicitConversion(*this, Loc, From, Converter); } /// IsAcceptableNonMemberOperatorCandidate - Determine whether Fn is /// an acceptable non-member overloaded operator for a call whose /// arguments have types T1 (and, if non-empty, T2). This routine /// implements the check in C++ [over.match.oper]p3b2 concerning /// enumeration types. static bool IsAcceptableNonMemberOperatorCandidate(ASTContext &Context, FunctionDecl *Fn, ArrayRef Args) { QualType T1 = Args[0]->getType(); QualType T2 = Args.size() > 1 ? Args[1]->getType() : QualType(); if (T1->isDependentType() || (!T2.isNull() && T2->isDependentType())) return true; if (T1->isRecordType() || (!T2.isNull() && T2->isRecordType())) return true; const auto *Proto = Fn->getType()->castAs(); if (Proto->getNumParams() < 1) return false; if (T1->isEnumeralType()) { QualType ArgType = Proto->getParamType(0).getNonReferenceType(); if (Context.hasSameUnqualifiedType(T1, ArgType)) return true; } if (Proto->getNumParams() < 2) return false; if (!T2.isNull() && T2->isEnumeralType()) { QualType ArgType = Proto->getParamType(1).getNonReferenceType(); if (Context.hasSameUnqualifiedType(T2, ArgType)) return true; } return false; } /// AddOverloadCandidate - Adds the given function to the set of /// candidate functions, using the given function call arguments. If /// @p SuppressUserConversions, then don't allow user-defined /// conversions via constructors or conversion operators. /// /// \param PartialOverloading true if we are performing "partial" overloading /// based on an incomplete set of function arguments. This feature is used by /// code completion. void Sema::AddOverloadCandidate( FunctionDecl *Function, DeclAccessPair FoundDecl, ArrayRef Args, OverloadCandidateSet &CandidateSet, bool SuppressUserConversions, bool PartialOverloading, bool AllowExplicit, bool AllowExplicitConversions, ADLCallKind IsADLCandidate, ConversionSequenceList EarlyConversions, OverloadCandidateParamOrder PO) { const FunctionProtoType *Proto = dyn_cast(Function->getType()->getAs()); assert(Proto && "Functions without a prototype cannot be overloaded"); assert(!Function->getDescribedFunctionTemplate() && "Use AddTemplateOverloadCandidate for function templates"); if (CXXMethodDecl *Method = dyn_cast(Function)) { if (!isa(Method)) { // If we get here, it's because we're calling a member function // that is named without a member access expression (e.g., // "this->f") that was either written explicitly or created // implicitly. This can happen with a qualified call to a member // function, e.g., X::f(). We use an empty type for the implied // object argument (C++ [over.call.func]p3), and the acting context // is irrelevant. AddMethodCandidate(Method, FoundDecl, Method->getParent(), QualType(), Expr::Classification::makeSimpleLValue(), Args, CandidateSet, SuppressUserConversions, PartialOverloading, EarlyConversions, PO); return; } // We treat a constructor like a non-member function, since its object // argument doesn't participate in overload resolution. } if (!CandidateSet.isNewCandidate(Function, PO)) return; // C++11 [class.copy]p11: [DR1402] // A defaulted move constructor that is defined as deleted is ignored by // overload resolution. CXXConstructorDecl *Constructor = dyn_cast(Function); if (Constructor && Constructor->isDefaulted() && Constructor->isDeleted() && Constructor->isMoveConstructor()) return; // Overload resolution is always an unevaluated context. EnterExpressionEvaluationContext Unevaluated( *this, Sema::ExpressionEvaluationContext::Unevaluated); // C++ [over.match.oper]p3: // if no operand has a class type, only those non-member functions in the // lookup set that have a first parameter of type T1 or "reference to // (possibly cv-qualified) T1", when T1 is an enumeration type, or (if there // is a right operand) a second parameter of type T2 or "reference to // (possibly cv-qualified) T2", when T2 is an enumeration type, are // candidate functions. if (CandidateSet.getKind() == OverloadCandidateSet::CSK_Operator && !IsAcceptableNonMemberOperatorCandidate(Context, Function, Args)) return; // Add this candidate OverloadCandidate &Candidate = CandidateSet.addCandidate(Args.size(), EarlyConversions); Candidate.FoundDecl = FoundDecl; Candidate.Function = Function; Candidate.Viable = true; Candidate.RewriteKind = CandidateSet.getRewriteInfo().getRewriteKind(Function, PO); Candidate.IsSurrogate = false; Candidate.IsADLCandidate = IsADLCandidate; Candidate.IgnoreObjectArgument = false; Candidate.ExplicitCallArguments = Args.size(); // Explicit functions are not actually candidates at all if we're not // allowing them in this context, but keep them around so we can point // to them in diagnostics. if (!AllowExplicit && ExplicitSpecifier::getFromDecl(Function).isExplicit()) { Candidate.Viable = false; Candidate.FailureKind = ovl_fail_explicit; return; } if (Function->isMultiVersion() && Function->hasAttr() && !Function->getAttr()->isDefaultVersion()) { Candidate.Viable = false; Candidate.FailureKind = ovl_non_default_multiversion_function; return; } if (Constructor) { // C++ [class.copy]p3: // A member function template is never instantiated to perform the copy // of a class object to an object of its class type. QualType ClassType = Context.getTypeDeclType(Constructor->getParent()); if (Args.size() == 1 && Constructor->isSpecializationCopyingObject() && (Context.hasSameUnqualifiedType(ClassType, Args[0]->getType()) || IsDerivedFrom(Args[0]->getBeginLoc(), Args[0]->getType(), ClassType))) { Candidate.Viable = false; Candidate.FailureKind = ovl_fail_illegal_constructor; return; } // C++ [over.match.funcs]p8: (proposed DR resolution) // A constructor inherited from class type C that has a first parameter // of type "reference to P" (including such a constructor instantiated // from a template) is excluded from the set of candidate functions when // constructing an object of type cv D if the argument list has exactly // one argument and D is reference-related to P and P is reference-related // to C. auto *Shadow = dyn_cast(FoundDecl.getDecl()); if (Shadow && Args.size() == 1 && Constructor->getNumParams() >= 1 && Constructor->getParamDecl(0)->getType()->isReferenceType()) { QualType P = Constructor->getParamDecl(0)->getType()->getPointeeType(); QualType C = Context.getRecordType(Constructor->getParent()); QualType D = Context.getRecordType(Shadow->getParent()); SourceLocation Loc = Args.front()->getExprLoc(); if ((Context.hasSameUnqualifiedType(P, C) || IsDerivedFrom(Loc, P, C)) && (Context.hasSameUnqualifiedType(D, P) || IsDerivedFrom(Loc, D, P))) { Candidate.Viable = false; Candidate.FailureKind = ovl_fail_inhctor_slice; return; } } // Check that the constructor is capable of constructing an object in the // destination address space. if (!Qualifiers::isAddressSpaceSupersetOf( Constructor->getMethodQualifiers().getAddressSpace(), CandidateSet.getDestAS())) { Candidate.Viable = false; Candidate.FailureKind = ovl_fail_object_addrspace_mismatch; } } unsigned NumParams = Proto->getNumParams(); // (C++ 13.3.2p2): A candidate function having fewer than m // parameters is viable only if it has an ellipsis in its parameter // list (8.3.5). if (TooManyArguments(NumParams, Args.size(), PartialOverloading) && !Proto->isVariadic()) { Candidate.Viable = false; Candidate.FailureKind = ovl_fail_too_many_arguments; return; } // (C++ 13.3.2p2): A candidate function having more than m parameters // is viable only if the (m+1)st parameter has a default argument // (8.3.6). For the purposes of overload resolution, the // parameter list is truncated on the right, so that there are // exactly m parameters. unsigned MinRequiredArgs = Function->getMinRequiredArguments(); if (Args.size() < MinRequiredArgs && !PartialOverloading) { // Not enough arguments. Candidate.Viable = false; Candidate.FailureKind = ovl_fail_too_few_arguments; return; } // (CUDA B.1): Check for invalid calls between targets. if (getLangOpts().CUDA) if (const FunctionDecl *Caller = dyn_cast(CurContext)) // Skip the check for callers that are implicit members, because in this // case we may not yet know what the member's target is; the target is // inferred for the member automatically, based on the bases and fields of // the class. if (!Caller->isImplicit() && !IsAllowedCUDACall(Caller, Function)) { Candidate.Viable = false; Candidate.FailureKind = ovl_fail_bad_target; return; } if (Function->getTrailingRequiresClause()) { ConstraintSatisfaction Satisfaction; if (CheckFunctionConstraints(Function, Satisfaction) || !Satisfaction.IsSatisfied) { Candidate.Viable = false; Candidate.FailureKind = ovl_fail_constraints_not_satisfied; return; } } // Determine the implicit conversion sequences for each of the // arguments. for (unsigned ArgIdx = 0; ArgIdx < Args.size(); ++ArgIdx) { unsigned ConvIdx = PO == OverloadCandidateParamOrder::Reversed ? 1 - ArgIdx : ArgIdx; if (Candidate.Conversions[ConvIdx].isInitialized()) { // We already formed a conversion sequence for this parameter during // template argument deduction. } else if (ArgIdx < NumParams) { // (C++ 13.3.2p3): for F to be a viable function, there shall // exist for each argument an implicit conversion sequence // (13.3.3.1) that converts that argument to the corresponding // parameter of F. QualType ParamType = Proto->getParamType(ArgIdx); Candidate.Conversions[ConvIdx] = TryCopyInitialization( *this, Args[ArgIdx], ParamType, SuppressUserConversions, /*InOverloadResolution=*/true, /*AllowObjCWritebackConversion=*/ getLangOpts().ObjCAutoRefCount, AllowExplicitConversions); if (Candidate.Conversions[ConvIdx].isBad()) { Candidate.Viable = false; Candidate.FailureKind = ovl_fail_bad_conversion; return; } } else { // (C++ 13.3.2p2): For the purposes of overload resolution, any // argument for which there is no corresponding parameter is // considered to ""match the ellipsis" (C+ 13.3.3.1.3). Candidate.Conversions[ConvIdx].setEllipsis(); } } if (EnableIfAttr *FailedAttr = CheckEnableIf(Function, CandidateSet.getLocation(), Args)) { Candidate.Viable = false; Candidate.FailureKind = ovl_fail_enable_if; Candidate.DeductionFailure.Data = FailedAttr; return; } } ObjCMethodDecl * Sema::SelectBestMethod(Selector Sel, MultiExprArg Args, bool IsInstance, SmallVectorImpl &Methods) { if (Methods.size() <= 1) return nullptr; for (unsigned b = 0, e = Methods.size(); b < e; b++) { bool Match = true; ObjCMethodDecl *Method = Methods[b]; unsigned NumNamedArgs = Sel.getNumArgs(); // Method might have more arguments than selector indicates. This is due // to addition of c-style arguments in method. if (Method->param_size() > NumNamedArgs) NumNamedArgs = Method->param_size(); if (Args.size() < NumNamedArgs) continue; for (unsigned i = 0; i < NumNamedArgs; i++) { // We can't do any type-checking on a type-dependent argument. if (Args[i]->isTypeDependent()) { Match = false; break; } ParmVarDecl *param = Method->parameters()[i]; Expr *argExpr = Args[i]; assert(argExpr && "SelectBestMethod(): missing expression"); // Strip the unbridged-cast placeholder expression off unless it's // a consumed argument. if (argExpr->hasPlaceholderType(BuiltinType::ARCUnbridgedCast) && !param->hasAttr()) argExpr = stripARCUnbridgedCast(argExpr); // If the parameter is __unknown_anytype, move on to the next method. if (param->getType() == Context.UnknownAnyTy) { Match = false; break; } ImplicitConversionSequence ConversionState = TryCopyInitialization(*this, argExpr, param->getType(), /*SuppressUserConversions*/false, /*InOverloadResolution=*/true, /*AllowObjCWritebackConversion=*/ getLangOpts().ObjCAutoRefCount, /*AllowExplicit*/false); // This function looks for a reasonably-exact match, so we consider // incompatible pointer conversions to be a failure here. if (ConversionState.isBad() || (ConversionState.isStandard() && ConversionState.Standard.Second == ICK_Incompatible_Pointer_Conversion)) { Match = false; break; } } // Promote additional arguments to variadic methods. if (Match && Method->isVariadic()) { for (unsigned i = NumNamedArgs, e = Args.size(); i < e; ++i) { if (Args[i]->isTypeDependent()) { Match = false; break; } ExprResult Arg = DefaultVariadicArgumentPromotion(Args[i], VariadicMethod, nullptr); if (Arg.isInvalid()) { Match = false; break; } } } else { // Check for extra arguments to non-variadic methods. if (Args.size() != NumNamedArgs) Match = false; else if (Match && NumNamedArgs == 0 && Methods.size() > 1) { // Special case when selectors have no argument. In this case, select // one with the most general result type of 'id'. for (unsigned b = 0, e = Methods.size(); b < e; b++) { QualType ReturnT = Methods[b]->getReturnType(); if (ReturnT->isObjCIdType()) return Methods[b]; } } } if (Match) return Method; } return nullptr; } static bool convertArgsForAvailabilityChecks( Sema &S, FunctionDecl *Function, Expr *ThisArg, SourceLocation CallLoc, ArrayRef Args, Sema::SFINAETrap &Trap, bool MissingImplicitThis, Expr *&ConvertedThis, SmallVectorImpl &ConvertedArgs) { if (ThisArg) { CXXMethodDecl *Method = cast(Function); assert(!isa(Method) && "Shouldn't have `this` for ctors!"); assert(!Method->isStatic() && "Shouldn't have `this` for static methods!"); ExprResult R = S.PerformObjectArgumentInitialization( ThisArg, /*Qualifier=*/nullptr, Method, Method); if (R.isInvalid()) return false; ConvertedThis = R.get(); } else { if (auto *MD = dyn_cast(Function)) { (void)MD; assert((MissingImplicitThis || MD->isStatic() || isa(MD)) && "Expected `this` for non-ctor instance methods"); } ConvertedThis = nullptr; } // Ignore any variadic arguments. Converting them is pointless, since the // user can't refer to them in the function condition. unsigned ArgSizeNoVarargs = std::min(Function->param_size(), Args.size()); // Convert the arguments. for (unsigned I = 0; I != ArgSizeNoVarargs; ++I) { ExprResult R; R = S.PerformCopyInitialization(InitializedEntity::InitializeParameter( S.Context, Function->getParamDecl(I)), SourceLocation(), Args[I]); if (R.isInvalid()) return false; ConvertedArgs.push_back(R.get()); } if (Trap.hasErrorOccurred()) return false; // Push default arguments if needed. if (!Function->isVariadic() && Args.size() < Function->getNumParams()) { for (unsigned i = Args.size(), e = Function->getNumParams(); i != e; ++i) { ParmVarDecl *P = Function->getParamDecl(i); if (!P->hasDefaultArg()) return false; ExprResult R = S.BuildCXXDefaultArgExpr(CallLoc, Function, P); if (R.isInvalid()) return false; ConvertedArgs.push_back(R.get()); } if (Trap.hasErrorOccurred()) return false; } return true; } EnableIfAttr *Sema::CheckEnableIf(FunctionDecl *Function, SourceLocation CallLoc, ArrayRef Args, bool MissingImplicitThis) { auto EnableIfAttrs = Function->specific_attrs(); if (EnableIfAttrs.begin() == EnableIfAttrs.end()) return nullptr; SFINAETrap Trap(*this); SmallVector ConvertedArgs; // FIXME: We should look into making enable_if late-parsed. Expr *DiscardedThis; if (!convertArgsForAvailabilityChecks( *this, Function, /*ThisArg=*/nullptr, CallLoc, Args, Trap, /*MissingImplicitThis=*/true, DiscardedThis, ConvertedArgs)) return *EnableIfAttrs.begin(); for (auto *EIA : EnableIfAttrs) { APValue Result; // FIXME: This doesn't consider value-dependent cases, because doing so is // very difficult. Ideally, we should handle them more gracefully. if (EIA->getCond()->isValueDependent() || !EIA->getCond()->EvaluateWithSubstitution( Result, Context, Function, llvm::makeArrayRef(ConvertedArgs))) return EIA; if (!Result.isInt() || !Result.getInt().getBoolValue()) return EIA; } return nullptr; } template static bool diagnoseDiagnoseIfAttrsWith(Sema &S, const NamedDecl *ND, bool ArgDependent, SourceLocation Loc, CheckFn &&IsSuccessful) { SmallVector Attrs; for (const auto *DIA : ND->specific_attrs()) { if (ArgDependent == DIA->getArgDependent()) Attrs.push_back(DIA); } // Common case: No diagnose_if attributes, so we can quit early. if (Attrs.empty()) return false; auto WarningBegin = std::stable_partition( Attrs.begin(), Attrs.end(), [](const DiagnoseIfAttr *DIA) { return DIA->isError(); }); // Note that diagnose_if attributes are late-parsed, so they appear in the // correct order (unlike enable_if attributes). auto ErrAttr = llvm::find_if(llvm::make_range(Attrs.begin(), WarningBegin), IsSuccessful); if (ErrAttr != WarningBegin) { const DiagnoseIfAttr *DIA = *ErrAttr; S.Diag(Loc, diag::err_diagnose_if_succeeded) << DIA->getMessage(); S.Diag(DIA->getLocation(), diag::note_from_diagnose_if) << DIA->getParent() << DIA->getCond()->getSourceRange(); return true; } for (const auto *DIA : llvm::make_range(WarningBegin, Attrs.end())) if (IsSuccessful(DIA)) { S.Diag(Loc, diag::warn_diagnose_if_succeeded) << DIA->getMessage(); S.Diag(DIA->getLocation(), diag::note_from_diagnose_if) << DIA->getParent() << DIA->getCond()->getSourceRange(); } return false; } bool Sema::diagnoseArgDependentDiagnoseIfAttrs(const FunctionDecl *Function, const Expr *ThisArg, ArrayRef Args, SourceLocation Loc) { return diagnoseDiagnoseIfAttrsWith( *this, Function, /*ArgDependent=*/true, Loc, [&](const DiagnoseIfAttr *DIA) { APValue Result; // It's sane to use the same Args for any redecl of this function, since // EvaluateWithSubstitution only cares about the position of each // argument in the arg list, not the ParmVarDecl* it maps to. if (!DIA->getCond()->EvaluateWithSubstitution( Result, Context, cast(DIA->getParent()), Args, ThisArg)) return false; return Result.isInt() && Result.getInt().getBoolValue(); }); } bool Sema::diagnoseArgIndependentDiagnoseIfAttrs(const NamedDecl *ND, SourceLocation Loc) { return diagnoseDiagnoseIfAttrsWith( *this, ND, /*ArgDependent=*/false, Loc, [&](const DiagnoseIfAttr *DIA) { bool Result; return DIA->getCond()->EvaluateAsBooleanCondition(Result, Context) && Result; }); } /// Add all of the function declarations in the given function set to /// the overload candidate set. void Sema::AddFunctionCandidates(const UnresolvedSetImpl &Fns, ArrayRef Args, OverloadCandidateSet &CandidateSet, TemplateArgumentListInfo *ExplicitTemplateArgs, bool SuppressUserConversions, bool PartialOverloading, bool FirstArgumentIsBase) { for (UnresolvedSetIterator F = Fns.begin(), E = Fns.end(); F != E; ++F) { NamedDecl *D = F.getDecl()->getUnderlyingDecl(); ArrayRef FunctionArgs = Args; FunctionTemplateDecl *FunTmpl = dyn_cast(D); FunctionDecl *FD = FunTmpl ? FunTmpl->getTemplatedDecl() : cast(D); if (isa(FD) && !cast(FD)->isStatic()) { QualType ObjectType; Expr::Classification ObjectClassification; if (Args.size() > 0) { if (Expr *E = Args[0]) { // Use the explicit base to restrict the lookup: ObjectType = E->getType(); // Pointers in the object arguments are implicitly dereferenced, so we // always classify them as l-values. if (!ObjectType.isNull() && ObjectType->isPointerType()) ObjectClassification = Expr::Classification::makeSimpleLValue(); else ObjectClassification = E->Classify(Context); } // .. else there is an implicit base. FunctionArgs = Args.slice(1); } if (FunTmpl) { AddMethodTemplateCandidate( FunTmpl, F.getPair(), cast(FunTmpl->getDeclContext()), ExplicitTemplateArgs, ObjectType, ObjectClassification, FunctionArgs, CandidateSet, SuppressUserConversions, PartialOverloading); } else { AddMethodCandidate(cast(FD), F.getPair(), cast(FD)->getParent(), ObjectType, ObjectClassification, FunctionArgs, CandidateSet, SuppressUserConversions, PartialOverloading); } } else { // This branch handles both standalone functions and static methods. // Slice the first argument (which is the base) when we access // static method as non-static. if (Args.size() > 0 && (!Args[0] || (FirstArgumentIsBase && isa(FD) && !isa(FD)))) { assert(cast(FD)->isStatic()); FunctionArgs = Args.slice(1); } if (FunTmpl) { AddTemplateOverloadCandidate(FunTmpl, F.getPair(), ExplicitTemplateArgs, FunctionArgs, CandidateSet, SuppressUserConversions, PartialOverloading); } else { AddOverloadCandidate(FD, F.getPair(), FunctionArgs, CandidateSet, SuppressUserConversions, PartialOverloading); } } } } /// AddMethodCandidate - Adds a named decl (which is some kind of /// method) as a method candidate to the given overload set. void Sema::AddMethodCandidate(DeclAccessPair FoundDecl, QualType ObjectType, Expr::Classification ObjectClassification, ArrayRef Args, OverloadCandidateSet &CandidateSet, bool SuppressUserConversions, OverloadCandidateParamOrder PO) { NamedDecl *Decl = FoundDecl.getDecl(); CXXRecordDecl *ActingContext = cast(Decl->getDeclContext()); if (isa(Decl)) Decl = cast(Decl)->getTargetDecl(); if (FunctionTemplateDecl *TD = dyn_cast(Decl)) { assert(isa(TD->getTemplatedDecl()) && "Expected a member function template"); AddMethodTemplateCandidate(TD, FoundDecl, ActingContext, /*ExplicitArgs*/ nullptr, ObjectType, ObjectClassification, Args, CandidateSet, SuppressUserConversions, false, PO); } else { AddMethodCandidate(cast(Decl), FoundDecl, ActingContext, ObjectType, ObjectClassification, Args, CandidateSet, SuppressUserConversions, false, None, PO); } } /// AddMethodCandidate - Adds the given C++ member function to the set /// of candidate functions, using the given function call arguments /// and the object argument (@c Object). For example, in a call /// @c o.f(a1,a2), @c Object will contain @c o and @c Args will contain /// both @c a1 and @c a2. If @p SuppressUserConversions, then don't /// allow user-defined conversions via constructors or conversion /// operators. void Sema::AddMethodCandidate(CXXMethodDecl *Method, DeclAccessPair FoundDecl, CXXRecordDecl *ActingContext, QualType ObjectType, Expr::Classification ObjectClassification, ArrayRef Args, OverloadCandidateSet &CandidateSet, bool SuppressUserConversions, bool PartialOverloading, ConversionSequenceList EarlyConversions, OverloadCandidateParamOrder PO) { const FunctionProtoType *Proto = dyn_cast(Method->getType()->getAs()); assert(Proto && "Methods without a prototype cannot be overloaded"); assert(!isa(Method) && "Use AddOverloadCandidate for constructors"); if (!CandidateSet.isNewCandidate(Method, PO)) return; // C++11 [class.copy]p23: [DR1402] // A defaulted move assignment operator that is defined as deleted is // ignored by overload resolution. if (Method->isDefaulted() && Method->isDeleted() && Method->isMoveAssignmentOperator()) return; // Overload resolution is always an unevaluated context. EnterExpressionEvaluationContext Unevaluated( *this, Sema::ExpressionEvaluationContext::Unevaluated); // Add this candidate OverloadCandidate &Candidate = CandidateSet.addCandidate(Args.size() + 1, EarlyConversions); Candidate.FoundDecl = FoundDecl; Candidate.Function = Method; Candidate.RewriteKind = CandidateSet.getRewriteInfo().getRewriteKind(Method, PO); Candidate.IsSurrogate = false; Candidate.IgnoreObjectArgument = false; Candidate.ExplicitCallArguments = Args.size(); unsigned NumParams = Proto->getNumParams(); // (C++ 13.3.2p2): A candidate function having fewer than m // parameters is viable only if it has an ellipsis in its parameter // list (8.3.5). if (TooManyArguments(NumParams, Args.size(), PartialOverloading) && !Proto->isVariadic()) { Candidate.Viable = false; Candidate.FailureKind = ovl_fail_too_many_arguments; return; } // (C++ 13.3.2p2): A candidate function having more than m parameters // is viable only if the (m+1)st parameter has a default argument // (8.3.6). For the purposes of overload resolution, the // parameter list is truncated on the right, so that there are // exactly m parameters. unsigned MinRequiredArgs = Method->getMinRequiredArguments(); if (Args.size() < MinRequiredArgs && !PartialOverloading) { // Not enough arguments. Candidate.Viable = false; Candidate.FailureKind = ovl_fail_too_few_arguments; return; } Candidate.Viable = true; if (Method->isStatic() || ObjectType.isNull()) // The implicit object argument is ignored. Candidate.IgnoreObjectArgument = true; else { unsigned ConvIdx = PO == OverloadCandidateParamOrder::Reversed ? 1 : 0; // Determine the implicit conversion sequence for the object // parameter. Candidate.Conversions[ConvIdx] = TryObjectArgumentInitialization( *this, CandidateSet.getLocation(), ObjectType, ObjectClassification, Method, ActingContext); if (Candidate.Conversions[ConvIdx].isBad()) { Candidate.Viable = false; Candidate.FailureKind = ovl_fail_bad_conversion; return; } } // (CUDA B.1): Check for invalid calls between targets. if (getLangOpts().CUDA) if (const FunctionDecl *Caller = dyn_cast(CurContext)) if (!IsAllowedCUDACall(Caller, Method)) { Candidate.Viable = false; Candidate.FailureKind = ovl_fail_bad_target; return; } if (Method->getTrailingRequiresClause()) { ConstraintSatisfaction Satisfaction; if (CheckFunctionConstraints(Method, Satisfaction) || !Satisfaction.IsSatisfied) { Candidate.Viable = false; Candidate.FailureKind = ovl_fail_constraints_not_satisfied; return; } } // Determine the implicit conversion sequences for each of the // arguments. for (unsigned ArgIdx = 0; ArgIdx < Args.size(); ++ArgIdx) { unsigned ConvIdx = PO == OverloadCandidateParamOrder::Reversed ? 0 : (ArgIdx + 1); if (Candidate.Conversions[ConvIdx].isInitialized()) { // We already formed a conversion sequence for this parameter during // template argument deduction. } else if (ArgIdx < NumParams) { // (C++ 13.3.2p3): for F to be a viable function, there shall // exist for each argument an implicit conversion sequence // (13.3.3.1) that converts that argument to the corresponding // parameter of F. QualType ParamType = Proto->getParamType(ArgIdx); Candidate.Conversions[ConvIdx] = TryCopyInitialization(*this, Args[ArgIdx], ParamType, SuppressUserConversions, /*InOverloadResolution=*/true, /*AllowObjCWritebackConversion=*/ getLangOpts().ObjCAutoRefCount); if (Candidate.Conversions[ConvIdx].isBad()) { Candidate.Viable = false; Candidate.FailureKind = ovl_fail_bad_conversion; return; } } else { // (C++ 13.3.2p2): For the purposes of overload resolution, any // argument for which there is no corresponding parameter is // considered to "match the ellipsis" (C+ 13.3.3.1.3). Candidate.Conversions[ConvIdx].setEllipsis(); } } if (EnableIfAttr *FailedAttr = CheckEnableIf(Method, CandidateSet.getLocation(), Args, true)) { Candidate.Viable = false; Candidate.FailureKind = ovl_fail_enable_if; Candidate.DeductionFailure.Data = FailedAttr; return; } if (Method->isMultiVersion() && Method->hasAttr() && !Method->getAttr()->isDefaultVersion()) { Candidate.Viable = false; Candidate.FailureKind = ovl_non_default_multiversion_function; } } /// Add a C++ member function template as a candidate to the candidate /// set, using template argument deduction to produce an appropriate member /// function template specialization. void Sema::AddMethodTemplateCandidate( FunctionTemplateDecl *MethodTmpl, DeclAccessPair FoundDecl, CXXRecordDecl *ActingContext, TemplateArgumentListInfo *ExplicitTemplateArgs, QualType ObjectType, Expr::Classification ObjectClassification, ArrayRef Args, OverloadCandidateSet &CandidateSet, bool SuppressUserConversions, bool PartialOverloading, OverloadCandidateParamOrder PO) { if (!CandidateSet.isNewCandidate(MethodTmpl, PO)) return; // C++ [over.match.funcs]p7: // In each case where a candidate is a function template, candidate // function template specializations are generated using template argument // deduction (14.8.3, 14.8.2). Those candidates are then handled as // candidate functions in the usual way.113) A given name can refer to one // or more function templates and also to a set of overloaded non-template // functions. In such a case, the candidate functions generated from each // function template are combined with the set of non-template candidate // functions. TemplateDeductionInfo Info(CandidateSet.getLocation()); FunctionDecl *Specialization = nullptr; ConversionSequenceList Conversions; if (TemplateDeductionResult Result = DeduceTemplateArguments( MethodTmpl, ExplicitTemplateArgs, Args, Specialization, Info, PartialOverloading, [&](ArrayRef ParamTypes) { return CheckNonDependentConversions( MethodTmpl, ParamTypes, Args, CandidateSet, Conversions, SuppressUserConversions, ActingContext, ObjectType, ObjectClassification, PO); })) { OverloadCandidate &Candidate = CandidateSet.addCandidate(Conversions.size(), Conversions); Candidate.FoundDecl = FoundDecl; Candidate.Function = MethodTmpl->getTemplatedDecl(); Candidate.Viable = false; Candidate.RewriteKind = CandidateSet.getRewriteInfo().getRewriteKind(Candidate.Function, PO); Candidate.IsSurrogate = false; Candidate.IgnoreObjectArgument = cast(Candidate.Function)->isStatic() || ObjectType.isNull(); Candidate.ExplicitCallArguments = Args.size(); if (Result == TDK_NonDependentConversionFailure) Candidate.FailureKind = ovl_fail_bad_conversion; else { Candidate.FailureKind = ovl_fail_bad_deduction; Candidate.DeductionFailure = MakeDeductionFailureInfo(Context, Result, Info); } return; } // Add the function template specialization produced by template argument // deduction as a candidate. assert(Specialization && "Missing member function template specialization?"); assert(isa(Specialization) && "Specialization is not a member function?"); AddMethodCandidate(cast(Specialization), FoundDecl, ActingContext, ObjectType, ObjectClassification, Args, CandidateSet, SuppressUserConversions, PartialOverloading, Conversions, PO); } /// Determine whether a given function template has a simple explicit specifier /// or a non-value-dependent explicit-specification that evaluates to true. static bool isNonDependentlyExplicit(FunctionTemplateDecl *FTD) { return ExplicitSpecifier::getFromDecl(FTD->getTemplatedDecl()).isExplicit(); } /// Add a C++ function template specialization as a candidate /// in the candidate set, using template argument deduction to produce /// an appropriate function template specialization. void Sema::AddTemplateOverloadCandidate( FunctionTemplateDecl *FunctionTemplate, DeclAccessPair FoundDecl, TemplateArgumentListInfo *ExplicitTemplateArgs, ArrayRef Args, OverloadCandidateSet &CandidateSet, bool SuppressUserConversions, bool PartialOverloading, bool AllowExplicit, ADLCallKind IsADLCandidate, OverloadCandidateParamOrder PO) { if (!CandidateSet.isNewCandidate(FunctionTemplate, PO)) return; // If the function template has a non-dependent explicit specification, // exclude it now if appropriate; we are not permitted to perform deduction // and substitution in this case. if (!AllowExplicit && isNonDependentlyExplicit(FunctionTemplate)) { OverloadCandidate &Candidate = CandidateSet.addCandidate(); Candidate.FoundDecl = FoundDecl; Candidate.Function = FunctionTemplate->getTemplatedDecl(); Candidate.Viable = false; Candidate.FailureKind = ovl_fail_explicit; return; } // C++ [over.match.funcs]p7: // In each case where a candidate is a function template, candidate // function template specializations are generated using template argument // deduction (14.8.3, 14.8.2). Those candidates are then handled as // candidate functions in the usual way.113) A given name can refer to one // or more function templates and also to a set of overloaded non-template // functions. In such a case, the candidate functions generated from each // function template are combined with the set of non-template candidate // functions. TemplateDeductionInfo Info(CandidateSet.getLocation()); FunctionDecl *Specialization = nullptr; ConversionSequenceList Conversions; if (TemplateDeductionResult Result = DeduceTemplateArguments( FunctionTemplate, ExplicitTemplateArgs, Args, Specialization, Info, PartialOverloading, [&](ArrayRef ParamTypes) { return CheckNonDependentConversions( FunctionTemplate, ParamTypes, Args, CandidateSet, Conversions, SuppressUserConversions, nullptr, QualType(), {}, PO); })) { OverloadCandidate &Candidate = CandidateSet.addCandidate(Conversions.size(), Conversions); Candidate.FoundDecl = FoundDecl; Candidate.Function = FunctionTemplate->getTemplatedDecl(); Candidate.Viable = false; Candidate.RewriteKind = CandidateSet.getRewriteInfo().getRewriteKind(Candidate.Function, PO); Candidate.IsSurrogate = false; Candidate.IsADLCandidate = IsADLCandidate; // Ignore the object argument if there is one, since we don't have an object // type. Candidate.IgnoreObjectArgument = isa(Candidate.Function) && !isa(Candidate.Function); Candidate.ExplicitCallArguments = Args.size(); if (Result == TDK_NonDependentConversionFailure) Candidate.FailureKind = ovl_fail_bad_conversion; else { Candidate.FailureKind = ovl_fail_bad_deduction; Candidate.DeductionFailure = MakeDeductionFailureInfo(Context, Result, Info); } return; } // Add the function template specialization produced by template argument // deduction as a candidate. assert(Specialization && "Missing function template specialization?"); AddOverloadCandidate( Specialization, FoundDecl, Args, CandidateSet, SuppressUserConversions, PartialOverloading, AllowExplicit, /*AllowExplicitConversions*/ false, IsADLCandidate, Conversions, PO); } /// Check that implicit conversion sequences can be formed for each argument /// whose corresponding parameter has a non-dependent type, per DR1391's /// [temp.deduct.call]p10. bool Sema::CheckNonDependentConversions( FunctionTemplateDecl *FunctionTemplate, ArrayRef ParamTypes, ArrayRef Args, OverloadCandidateSet &CandidateSet, ConversionSequenceList &Conversions, bool SuppressUserConversions, CXXRecordDecl *ActingContext, QualType ObjectType, Expr::Classification ObjectClassification, OverloadCandidateParamOrder PO) { // FIXME: The cases in which we allow explicit conversions for constructor // arguments never consider calling a constructor template. It's not clear // that is correct. const bool AllowExplicit = false; auto *FD = FunctionTemplate->getTemplatedDecl(); auto *Method = dyn_cast(FD); bool HasThisConversion = Method && !isa(Method); unsigned ThisConversions = HasThisConversion ? 1 : 0; Conversions = CandidateSet.allocateConversionSequences(ThisConversions + Args.size()); // Overload resolution is always an unevaluated context. EnterExpressionEvaluationContext Unevaluated( *this, Sema::ExpressionEvaluationContext::Unevaluated); // For a method call, check the 'this' conversion here too. DR1391 doesn't // require that, but this check should never result in a hard error, and // overload resolution is permitted to sidestep instantiations. if (HasThisConversion && !cast(FD)->isStatic() && !ObjectType.isNull()) { unsigned ConvIdx = PO == OverloadCandidateParamOrder::Reversed ? 1 : 0; Conversions[ConvIdx] = TryObjectArgumentInitialization( *this, CandidateSet.getLocation(), ObjectType, ObjectClassification, Method, ActingContext); if (Conversions[ConvIdx].isBad()) return true; } for (unsigned I = 0, N = std::min(ParamTypes.size(), Args.size()); I != N; ++I) { QualType ParamType = ParamTypes[I]; if (!ParamType->isDependentType()) { unsigned ConvIdx = PO == OverloadCandidateParamOrder::Reversed ? 0 : (ThisConversions + I); Conversions[ConvIdx] = TryCopyInitialization(*this, Args[I], ParamType, SuppressUserConversions, /*InOverloadResolution=*/true, /*AllowObjCWritebackConversion=*/ getLangOpts().ObjCAutoRefCount, AllowExplicit); if (Conversions[ConvIdx].isBad()) return true; } } return false; } /// Determine whether this is an allowable conversion from the result /// of an explicit conversion operator to the expected type, per C++ /// [over.match.conv]p1 and [over.match.ref]p1. /// /// \param ConvType The return type of the conversion function. /// /// \param ToType The type we are converting to. /// /// \param AllowObjCPointerConversion Allow a conversion from one /// Objective-C pointer to another. /// /// \returns true if the conversion is allowable, false otherwise. static bool isAllowableExplicitConversion(Sema &S, QualType ConvType, QualType ToType, bool AllowObjCPointerConversion) { QualType ToNonRefType = ToType.getNonReferenceType(); // Easy case: the types are the same. if (S.Context.hasSameUnqualifiedType(ConvType, ToNonRefType)) return true; // Allow qualification conversions. bool ObjCLifetimeConversion; if (S.IsQualificationConversion(ConvType, ToNonRefType, /*CStyle*/false, ObjCLifetimeConversion)) return true; // If we're not allowed to consider Objective-C pointer conversions, // we're done. if (!AllowObjCPointerConversion) return false; // Is this an Objective-C pointer conversion? bool IncompatibleObjC = false; QualType ConvertedType; return S.isObjCPointerConversion(ConvType, ToNonRefType, ConvertedType, IncompatibleObjC); } /// AddConversionCandidate - Add a C++ conversion function as a /// candidate in the candidate set (C++ [over.match.conv], /// C++ [over.match.copy]). From is the expression we're converting from, /// and ToType is the type that we're eventually trying to convert to /// (which may or may not be the same type as the type that the /// conversion function produces). void Sema::AddConversionCandidate( CXXConversionDecl *Conversion, DeclAccessPair FoundDecl, CXXRecordDecl *ActingContext, Expr *From, QualType ToType, OverloadCandidateSet &CandidateSet, bool AllowObjCConversionOnExplicit, bool AllowExplicit, bool AllowResultConversion) { assert(!Conversion->getDescribedFunctionTemplate() && "Conversion function templates use AddTemplateConversionCandidate"); QualType ConvType = Conversion->getConversionType().getNonReferenceType(); if (!CandidateSet.isNewCandidate(Conversion)) return; // If the conversion function has an undeduced return type, trigger its // deduction now. if (getLangOpts().CPlusPlus14 && ConvType->isUndeducedType()) { if (DeduceReturnType(Conversion, From->getExprLoc())) return; ConvType = Conversion->getConversionType().getNonReferenceType(); } // If we don't allow any conversion of the result type, ignore conversion // functions that don't convert to exactly (possibly cv-qualified) T. if (!AllowResultConversion && !Context.hasSameUnqualifiedType(Conversion->getConversionType(), ToType)) return; // Per C++ [over.match.conv]p1, [over.match.ref]p1, an explicit conversion // operator is only a candidate if its return type is the target type or // can be converted to the target type with a qualification conversion. // // FIXME: Include such functions in the candidate list and explain why we // can't select them. if (Conversion->isExplicit() && !isAllowableExplicitConversion(*this, ConvType, ToType, AllowObjCConversionOnExplicit)) return; // Overload resolution is always an unevaluated context. EnterExpressionEvaluationContext Unevaluated( *this, Sema::ExpressionEvaluationContext::Unevaluated); // Add this candidate OverloadCandidate &Candidate = CandidateSet.addCandidate(1); Candidate.FoundDecl = FoundDecl; Candidate.Function = Conversion; Candidate.IsSurrogate = false; Candidate.IgnoreObjectArgument = false; Candidate.FinalConversion.setAsIdentityConversion(); Candidate.FinalConversion.setFromType(ConvType); Candidate.FinalConversion.setAllToTypes(ToType); Candidate.Viable = true; Candidate.ExplicitCallArguments = 1; // Explicit functions are not actually candidates at all if we're not // allowing them in this context, but keep them around so we can point // to them in diagnostics. if (!AllowExplicit && Conversion->isExplicit()) { Candidate.Viable = false; Candidate.FailureKind = ovl_fail_explicit; return; } // C++ [over.match.funcs]p4: // For conversion functions, the function is considered to be a member of // the class of the implicit implied object argument for the purpose of // defining the type of the implicit object parameter. // // Determine the implicit conversion sequence for the implicit // object parameter. QualType ImplicitParamType = From->getType(); if (const PointerType *FromPtrType = ImplicitParamType->getAs()) ImplicitParamType = FromPtrType->getPointeeType(); CXXRecordDecl *ConversionContext = cast(ImplicitParamType->castAs()->getDecl()); Candidate.Conversions[0] = TryObjectArgumentInitialization( *this, CandidateSet.getLocation(), From->getType(), From->Classify(Context), Conversion, ConversionContext); if (Candidate.Conversions[0].isBad()) { Candidate.Viable = false; Candidate.FailureKind = ovl_fail_bad_conversion; return; } if (Conversion->getTrailingRequiresClause()) { ConstraintSatisfaction Satisfaction; if (CheckFunctionConstraints(Conversion, Satisfaction) || !Satisfaction.IsSatisfied) { Candidate.Viable = false; Candidate.FailureKind = ovl_fail_constraints_not_satisfied; return; } } // We won't go through a user-defined type conversion function to convert a // derived to base as such conversions are given Conversion Rank. They only // go through a copy constructor. 13.3.3.1.2-p4 [over.ics.user] QualType FromCanon = Context.getCanonicalType(From->getType().getUnqualifiedType()); QualType ToCanon = Context.getCanonicalType(ToType).getUnqualifiedType(); if (FromCanon == ToCanon || IsDerivedFrom(CandidateSet.getLocation(), FromCanon, ToCanon)) { Candidate.Viable = false; Candidate.FailureKind = ovl_fail_trivial_conversion; return; } // To determine what the conversion from the result of calling the // conversion function to the type we're eventually trying to // convert to (ToType), we need to synthesize a call to the // conversion function and attempt copy initialization from it. This // makes sure that we get the right semantics with respect to // lvalues/rvalues and the type. Fortunately, we can allocate this // call on the stack and we don't need its arguments to be // well-formed. DeclRefExpr ConversionRef(Context, Conversion, false, Conversion->getType(), VK_LValue, From->getBeginLoc()); ImplicitCastExpr ConversionFn(ImplicitCastExpr::OnStack, Context.getPointerType(Conversion->getType()), CK_FunctionToPointerDecay, &ConversionRef, VK_RValue, FPOptionsOverride()); QualType ConversionType = Conversion->getConversionType(); if (!isCompleteType(From->getBeginLoc(), ConversionType)) { Candidate.Viable = false; Candidate.FailureKind = ovl_fail_bad_final_conversion; return; } ExprValueKind VK = Expr::getValueKindForType(ConversionType); // Note that it is safe to allocate CallExpr on the stack here because // there are 0 arguments (i.e., nothing is allocated using ASTContext's // allocator). QualType CallResultType = ConversionType.getNonLValueExprType(Context); alignas(CallExpr) char Buffer[sizeof(CallExpr) + sizeof(Stmt *)]; CallExpr *TheTemporaryCall = CallExpr::CreateTemporary( Buffer, &ConversionFn, CallResultType, VK, From->getBeginLoc()); ImplicitConversionSequence ICS = TryCopyInitialization(*this, TheTemporaryCall, ToType, /*SuppressUserConversions=*/true, /*InOverloadResolution=*/false, /*AllowObjCWritebackConversion=*/false); switch (ICS.getKind()) { case ImplicitConversionSequence::StandardConversion: Candidate.FinalConversion = ICS.Standard; // C++ [over.ics.user]p3: // If the user-defined conversion is specified by a specialization of a // conversion function template, the second standard conversion sequence // shall have exact match rank. if (Conversion->getPrimaryTemplate() && GetConversionRank(ICS.Standard.Second) != ICR_Exact_Match) { Candidate.Viable = false; Candidate.FailureKind = ovl_fail_final_conversion_not_exact; return; } // C++0x [dcl.init.ref]p5: // In the second case, if the reference is an rvalue reference and // the second standard conversion sequence of the user-defined // conversion sequence includes an lvalue-to-rvalue conversion, the // program is ill-formed. if (ToType->isRValueReferenceType() && ICS.Standard.First == ICK_Lvalue_To_Rvalue) { Candidate.Viable = false; Candidate.FailureKind = ovl_fail_bad_final_conversion; return; } break; case ImplicitConversionSequence::BadConversion: Candidate.Viable = false; Candidate.FailureKind = ovl_fail_bad_final_conversion; return; default: llvm_unreachable( "Can only end up with a standard conversion sequence or failure"); } if (EnableIfAttr *FailedAttr = CheckEnableIf(Conversion, CandidateSet.getLocation(), None)) { Candidate.Viable = false; Candidate.FailureKind = ovl_fail_enable_if; Candidate.DeductionFailure.Data = FailedAttr; return; } if (Conversion->isMultiVersion() && Conversion->hasAttr() && !Conversion->getAttr()->isDefaultVersion()) { Candidate.Viable = false; Candidate.FailureKind = ovl_non_default_multiversion_function; } } /// Adds a conversion function template specialization /// candidate to the overload set, using template argument deduction /// to deduce the template arguments of the conversion function /// template from the type that we are converting to (C++ /// [temp.deduct.conv]). void Sema::AddTemplateConversionCandidate( FunctionTemplateDecl *FunctionTemplate, DeclAccessPair FoundDecl, CXXRecordDecl *ActingDC, Expr *From, QualType ToType, OverloadCandidateSet &CandidateSet, bool AllowObjCConversionOnExplicit, bool AllowExplicit, bool AllowResultConversion) { assert(isa(FunctionTemplate->getTemplatedDecl()) && "Only conversion function templates permitted here"); if (!CandidateSet.isNewCandidate(FunctionTemplate)) return; // If the function template has a non-dependent explicit specification, // exclude it now if appropriate; we are not permitted to perform deduction // and substitution in this case. if (!AllowExplicit && isNonDependentlyExplicit(FunctionTemplate)) { OverloadCandidate &Candidate = CandidateSet.addCandidate(); Candidate.FoundDecl = FoundDecl; Candidate.Function = FunctionTemplate->getTemplatedDecl(); Candidate.Viable = false; Candidate.FailureKind = ovl_fail_explicit; return; } TemplateDeductionInfo Info(CandidateSet.getLocation()); CXXConversionDecl *Specialization = nullptr; if (TemplateDeductionResult Result = DeduceTemplateArguments(FunctionTemplate, ToType, Specialization, Info)) { OverloadCandidate &Candidate = CandidateSet.addCandidate(); Candidate.FoundDecl = FoundDecl; Candidate.Function = FunctionTemplate->getTemplatedDecl(); Candidate.Viable = false; Candidate.FailureKind = ovl_fail_bad_deduction; Candidate.IsSurrogate = false; Candidate.IgnoreObjectArgument = false; Candidate.ExplicitCallArguments = 1; Candidate.DeductionFailure = MakeDeductionFailureInfo(Context, Result, Info); return; } // Add the conversion function template specialization produced by // template argument deduction as a candidate. assert(Specialization && "Missing function template specialization?"); AddConversionCandidate(Specialization, FoundDecl, ActingDC, From, ToType, CandidateSet, AllowObjCConversionOnExplicit, AllowExplicit, AllowResultConversion); } /// AddSurrogateCandidate - Adds a "surrogate" candidate function that /// converts the given @c Object to a function pointer via the /// conversion function @c Conversion, and then attempts to call it /// with the given arguments (C++ [over.call.object]p2-4). Proto is /// the type of function that we'll eventually be calling. void Sema::AddSurrogateCandidate(CXXConversionDecl *Conversion, DeclAccessPair FoundDecl, CXXRecordDecl *ActingContext, const FunctionProtoType *Proto, Expr *Object, ArrayRef Args, OverloadCandidateSet& CandidateSet) { if (!CandidateSet.isNewCandidate(Conversion)) return; // Overload resolution is always an unevaluated context. EnterExpressionEvaluationContext Unevaluated( *this, Sema::ExpressionEvaluationContext::Unevaluated); OverloadCandidate &Candidate = CandidateSet.addCandidate(Args.size() + 1); Candidate.FoundDecl = FoundDecl; Candidate.Function = nullptr; Candidate.Surrogate = Conversion; Candidate.Viable = true; Candidate.IsSurrogate = true; Candidate.IgnoreObjectArgument = false; Candidate.ExplicitCallArguments = Args.size(); // Determine the implicit conversion sequence for the implicit // object parameter. ImplicitConversionSequence ObjectInit = TryObjectArgumentInitialization( *this, CandidateSet.getLocation(), Object->getType(), Object->Classify(Context), Conversion, ActingContext); if (ObjectInit.isBad()) { Candidate.Viable = false; Candidate.FailureKind = ovl_fail_bad_conversion; Candidate.Conversions[0] = ObjectInit; return; } // The first conversion is actually a user-defined conversion whose // first conversion is ObjectInit's standard conversion (which is // effectively a reference binding). Record it as such. Candidate.Conversions[0].setUserDefined(); Candidate.Conversions[0].UserDefined.Before = ObjectInit.Standard; Candidate.Conversions[0].UserDefined.EllipsisConversion = false; Candidate.Conversions[0].UserDefined.HadMultipleCandidates = false; Candidate.Conversions[0].UserDefined.ConversionFunction = Conversion; Candidate.Conversions[0].UserDefined.FoundConversionFunction = FoundDecl; Candidate.Conversions[0].UserDefined.After = Candidate.Conversions[0].UserDefined.Before; Candidate.Conversions[0].UserDefined.After.setAsIdentityConversion(); // Find the unsigned NumParams = Proto->getNumParams(); // (C++ 13.3.2p2): A candidate function having fewer than m // parameters is viable only if it has an ellipsis in its parameter // list (8.3.5). if (Args.size() > NumParams && !Proto->isVariadic()) { Candidate.Viable = false; Candidate.FailureKind = ovl_fail_too_many_arguments; return; } // Function types don't have any default arguments, so just check if // we have enough arguments. if (Args.size() < NumParams) { // Not enough arguments. Candidate.Viable = false; Candidate.FailureKind = ovl_fail_too_few_arguments; return; } // Determine the implicit conversion sequences for each of the // arguments. for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) { if (ArgIdx < NumParams) { // (C++ 13.3.2p3): for F to be a viable function, there shall // exist for each argument an implicit conversion sequence // (13.3.3.1) that converts that argument to the corresponding // parameter of F. QualType ParamType = Proto->getParamType(ArgIdx); Candidate.Conversions[ArgIdx + 1] = TryCopyInitialization(*this, Args[ArgIdx], ParamType, /*SuppressUserConversions=*/false, /*InOverloadResolution=*/false, /*AllowObjCWritebackConversion=*/ getLangOpts().ObjCAutoRefCount); if (Candidate.Conversions[ArgIdx + 1].isBad()) { Candidate.Viable = false; Candidate.FailureKind = ovl_fail_bad_conversion; return; } } else { // (C++ 13.3.2p2): For the purposes of overload resolution, any // argument for which there is no corresponding parameter is // considered to ""match the ellipsis" (C+ 13.3.3.1.3). Candidate.Conversions[ArgIdx + 1].setEllipsis(); } } if (EnableIfAttr *FailedAttr = CheckEnableIf(Conversion, CandidateSet.getLocation(), None)) { Candidate.Viable = false; Candidate.FailureKind = ovl_fail_enable_if; Candidate.DeductionFailure.Data = FailedAttr; return; } } /// Add all of the non-member operator function declarations in the given /// function set to the overload candidate set. void Sema::AddNonMemberOperatorCandidates( const UnresolvedSetImpl &Fns, ArrayRef Args, OverloadCandidateSet &CandidateSet, TemplateArgumentListInfo *ExplicitTemplateArgs) { for (UnresolvedSetIterator F = Fns.begin(), E = Fns.end(); F != E; ++F) { NamedDecl *D = F.getDecl()->getUnderlyingDecl(); ArrayRef FunctionArgs = Args; FunctionTemplateDecl *FunTmpl = dyn_cast(D); FunctionDecl *FD = FunTmpl ? FunTmpl->getTemplatedDecl() : cast(D); // Don't consider rewritten functions if we're not rewriting. if (!CandidateSet.getRewriteInfo().isAcceptableCandidate(FD)) continue; assert(!isa(FD) && "unqualified operator lookup found a member function"); if (FunTmpl) { AddTemplateOverloadCandidate(FunTmpl, F.getPair(), ExplicitTemplateArgs, FunctionArgs, CandidateSet); if (CandidateSet.getRewriteInfo().shouldAddReversed(Context, FD)) AddTemplateOverloadCandidate( FunTmpl, F.getPair(), ExplicitTemplateArgs, {FunctionArgs[1], FunctionArgs[0]}, CandidateSet, false, false, true, ADLCallKind::NotADL, OverloadCandidateParamOrder::Reversed); } else { if (ExplicitTemplateArgs) continue; AddOverloadCandidate(FD, F.getPair(), FunctionArgs, CandidateSet); if (CandidateSet.getRewriteInfo().shouldAddReversed(Context, FD)) AddOverloadCandidate(FD, F.getPair(), {FunctionArgs[1], FunctionArgs[0]}, CandidateSet, false, false, true, false, ADLCallKind::NotADL, None, OverloadCandidateParamOrder::Reversed); } } } /// Add overload candidates for overloaded operators that are /// member functions. /// /// Add the overloaded operator candidates that are member functions /// for the operator Op that was used in an operator expression such /// as "x Op y". , Args/NumArgs provides the operator arguments, and /// CandidateSet will store the added overload candidates. (C++ /// [over.match.oper]). void Sema::AddMemberOperatorCandidates(OverloadedOperatorKind Op, SourceLocation OpLoc, ArrayRef Args, OverloadCandidateSet &CandidateSet, OverloadCandidateParamOrder PO) { DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); // C++ [over.match.oper]p3: // For a unary operator @ with an operand of a type whose // cv-unqualified version is T1, and for a binary operator @ with // a left operand of a type whose cv-unqualified version is T1 and // a right operand of a type whose cv-unqualified version is T2, // three sets of candidate functions, designated member // candidates, non-member candidates and built-in candidates, are // constructed as follows: QualType T1 = Args[0]->getType(); // -- If T1 is a complete class type or a class currently being // defined, the set of member candidates is the result of the // qualified lookup of T1::operator@ (13.3.1.1.1); otherwise, // the set of member candidates is empty. if (const RecordType *T1Rec = T1->getAs()) { // Complete the type if it can be completed. if (!isCompleteType(OpLoc, T1) && !T1Rec->isBeingDefined()) return; // If the type is neither complete nor being defined, bail out now. if (!T1Rec->getDecl()->getDefinition()) return; LookupResult Operators(*this, OpName, OpLoc, LookupOrdinaryName); LookupQualifiedName(Operators, T1Rec->getDecl()); Operators.suppressDiagnostics(); for (LookupResult::iterator Oper = Operators.begin(), OperEnd = Operators.end(); Oper != OperEnd; ++Oper) AddMethodCandidate(Oper.getPair(), Args[0]->getType(), Args[0]->Classify(Context), Args.slice(1), CandidateSet, /*SuppressUserConversion=*/false, PO); } } /// AddBuiltinCandidate - Add a candidate for a built-in /// operator. ResultTy and ParamTys are the result and parameter types /// of the built-in candidate, respectively. Args and NumArgs are the /// arguments being passed to the candidate. IsAssignmentOperator /// should be true when this built-in candidate is an assignment /// operator. NumContextualBoolArguments is the number of arguments /// (at the beginning of the argument list) that will be contextually /// converted to bool. void Sema::AddBuiltinCandidate(QualType *ParamTys, ArrayRef Args, OverloadCandidateSet& CandidateSet, bool IsAssignmentOperator, unsigned NumContextualBoolArguments) { // Overload resolution is always an unevaluated context. EnterExpressionEvaluationContext Unevaluated( *this, Sema::ExpressionEvaluationContext::Unevaluated); // Add this candidate OverloadCandidate &Candidate = CandidateSet.addCandidate(Args.size()); Candidate.FoundDecl = DeclAccessPair::make(nullptr, AS_none); Candidate.Function = nullptr; Candidate.IsSurrogate = false; Candidate.IgnoreObjectArgument = false; std::copy(ParamTys, ParamTys + Args.size(), Candidate.BuiltinParamTypes); // Determine the implicit conversion sequences for each of the // arguments. Candidate.Viable = true; Candidate.ExplicitCallArguments = Args.size(); for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) { // C++ [over.match.oper]p4: // For the built-in assignment operators, conversions of the // left operand are restricted as follows: // -- no temporaries are introduced to hold the left operand, and // -- no user-defined conversions are applied to the left // operand to achieve a type match with the left-most // parameter of a built-in candidate. // // We block these conversions by turning off user-defined // conversions, since that is the only way that initialization of // a reference to a non-class type can occur from something that // is not of the same type. if (ArgIdx < NumContextualBoolArguments) { assert(ParamTys[ArgIdx] == Context.BoolTy && "Contextual conversion to bool requires bool type"); Candidate.Conversions[ArgIdx] = TryContextuallyConvertToBool(*this, Args[ArgIdx]); } else { Candidate.Conversions[ArgIdx] = TryCopyInitialization(*this, Args[ArgIdx], ParamTys[ArgIdx], ArgIdx == 0 && IsAssignmentOperator, /*InOverloadResolution=*/false, /*AllowObjCWritebackConversion=*/ getLangOpts().ObjCAutoRefCount); } if (Candidate.Conversions[ArgIdx].isBad()) { Candidate.Viable = false; Candidate.FailureKind = ovl_fail_bad_conversion; break; } } } namespace { /// BuiltinCandidateTypeSet - A set of types that will be used for the /// candidate operator functions for built-in operators (C++ /// [over.built]). The types are separated into pointer types and /// enumeration types. class BuiltinCandidateTypeSet { /// TypeSet - A set of types. typedef llvm::SetVector, llvm::SmallPtrSet> TypeSet; /// PointerTypes - The set of pointer types that will be used in the /// built-in candidates. TypeSet PointerTypes; /// MemberPointerTypes - The set of member pointer types that will be /// used in the built-in candidates. TypeSet MemberPointerTypes; /// EnumerationTypes - The set of enumeration types that will be /// used in the built-in candidates. TypeSet EnumerationTypes; /// The set of vector types that will be used in the built-in /// candidates. TypeSet VectorTypes; /// The set of matrix types that will be used in the built-in /// candidates. TypeSet MatrixTypes; /// A flag indicating non-record types are viable candidates bool HasNonRecordTypes; /// A flag indicating whether either arithmetic or enumeration types /// were present in the candidate set. bool HasArithmeticOrEnumeralTypes; /// A flag indicating whether the nullptr type was present in the /// candidate set. bool HasNullPtrType; /// Sema - The semantic analysis instance where we are building the /// candidate type set. Sema &SemaRef; /// Context - The AST context in which we will build the type sets. ASTContext &Context; bool AddPointerWithMoreQualifiedTypeVariants(QualType Ty, const Qualifiers &VisibleQuals); bool AddMemberPointerWithMoreQualifiedTypeVariants(QualType Ty); public: /// iterator - Iterates through the types that are part of the set. typedef TypeSet::iterator iterator; BuiltinCandidateTypeSet(Sema &SemaRef) : HasNonRecordTypes(false), HasArithmeticOrEnumeralTypes(false), HasNullPtrType(false), SemaRef(SemaRef), Context(SemaRef.Context) { } void AddTypesConvertedFrom(QualType Ty, SourceLocation Loc, bool AllowUserConversions, bool AllowExplicitConversions, const Qualifiers &VisibleTypeConversionsQuals); llvm::iterator_range pointer_types() { return PointerTypes; } llvm::iterator_range member_pointer_types() { return MemberPointerTypes; } llvm::iterator_range enumeration_types() { return EnumerationTypes; } llvm::iterator_range vector_types() { return VectorTypes; } llvm::iterator_range matrix_types() { return MatrixTypes; } bool containsMatrixType(QualType Ty) const { return MatrixTypes.count(Ty); } bool hasNonRecordTypes() { return HasNonRecordTypes; } bool hasArithmeticOrEnumeralTypes() { return HasArithmeticOrEnumeralTypes; } bool hasNullPtrType() const { return HasNullPtrType; } }; } // end anonymous namespace /// AddPointerWithMoreQualifiedTypeVariants - Add the pointer type @p Ty to /// the set of pointer types along with any more-qualified variants of /// that type. For example, if @p Ty is "int const *", this routine /// will add "int const *", "int const volatile *", "int const /// restrict *", and "int const volatile restrict *" to the set of /// pointer types. Returns true if the add of @p Ty itself succeeded, /// false otherwise. /// /// FIXME: what to do about extended qualifiers? bool BuiltinCandidateTypeSet::AddPointerWithMoreQualifiedTypeVariants(QualType Ty, const Qualifiers &VisibleQuals) { // Insert this type. if (!PointerTypes.insert(Ty)) return false; QualType PointeeTy; const PointerType *PointerTy = Ty->getAs(); bool buildObjCPtr = false; if (!PointerTy) { const ObjCObjectPointerType *PTy = Ty->castAs(); PointeeTy = PTy->getPointeeType(); buildObjCPtr = true; } else { PointeeTy = PointerTy->getPointeeType(); } // Don't add qualified variants of arrays. For one, they're not allowed // (the qualifier would sink to the element type), and for another, the // only overload situation where it matters is subscript or pointer +- int, // and those shouldn't have qualifier variants anyway. if (PointeeTy->isArrayType()) return true; unsigned BaseCVR = PointeeTy.getCVRQualifiers(); bool hasVolatile = VisibleQuals.hasVolatile(); bool hasRestrict = VisibleQuals.hasRestrict(); // Iterate through all strict supersets of BaseCVR. for (unsigned CVR = BaseCVR+1; CVR <= Qualifiers::CVRMask; ++CVR) { if ((CVR | BaseCVR) != CVR) continue; // Skip over volatile if no volatile found anywhere in the types. if ((CVR & Qualifiers::Volatile) && !hasVolatile) continue; // Skip over restrict if no restrict found anywhere in the types, or if // the type cannot be restrict-qualified. if ((CVR & Qualifiers::Restrict) && (!hasRestrict || (!(PointeeTy->isAnyPointerType() || PointeeTy->isReferenceType())))) continue; // Build qualified pointee type. QualType QPointeeTy = Context.getCVRQualifiedType(PointeeTy, CVR); // Build qualified pointer type. QualType QPointerTy; if (!buildObjCPtr) QPointerTy = Context.getPointerType(QPointeeTy); else QPointerTy = Context.getObjCObjectPointerType(QPointeeTy); // Insert qualified pointer type. PointerTypes.insert(QPointerTy); } return true; } /// AddMemberPointerWithMoreQualifiedTypeVariants - Add the pointer type @p Ty /// to the set of pointer types along with any more-qualified variants of /// that type. For example, if @p Ty is "int const *", this routine /// will add "int const *", "int const volatile *", "int const /// restrict *", and "int const volatile restrict *" to the set of /// pointer types. Returns true if the add of @p Ty itself succeeded, /// false otherwise. /// /// FIXME: what to do about extended qualifiers? bool BuiltinCandidateTypeSet::AddMemberPointerWithMoreQualifiedTypeVariants( QualType Ty) { // Insert this type. if (!MemberPointerTypes.insert(Ty)) return false; const MemberPointerType *PointerTy = Ty->getAs(); assert(PointerTy && "type was not a member pointer type!"); QualType PointeeTy = PointerTy->getPointeeType(); // Don't add qualified variants of arrays. For one, they're not allowed // (the qualifier would sink to the element type), and for another, the // only overload situation where it matters is subscript or pointer +- int, // and those shouldn't have qualifier variants anyway. if (PointeeTy->isArrayType()) return true; const Type *ClassTy = PointerTy->getClass(); // Iterate through all strict supersets of the pointee type's CVR // qualifiers. unsigned BaseCVR = PointeeTy.getCVRQualifiers(); for (unsigned CVR = BaseCVR+1; CVR <= Qualifiers::CVRMask; ++CVR) { if ((CVR | BaseCVR) != CVR) continue; QualType QPointeeTy = Context.getCVRQualifiedType(PointeeTy, CVR); MemberPointerTypes.insert( Context.getMemberPointerType(QPointeeTy, ClassTy)); } return true; } /// AddTypesConvertedFrom - Add each of the types to which the type @p /// Ty can be implicit converted to the given set of @p Types. We're /// primarily interested in pointer types and enumeration types. We also /// take member pointer types, for the conditional operator. /// AllowUserConversions is true if we should look at the conversion /// functions of a class type, and AllowExplicitConversions if we /// should also include the explicit conversion functions of a class /// type. void BuiltinCandidateTypeSet::AddTypesConvertedFrom(QualType Ty, SourceLocation Loc, bool AllowUserConversions, bool AllowExplicitConversions, const Qualifiers &VisibleQuals) { // Only deal with canonical types. Ty = Context.getCanonicalType(Ty); // Look through reference types; they aren't part of the type of an // expression for the purposes of conversions. if (const ReferenceType *RefTy = Ty->getAs()) Ty = RefTy->getPointeeType(); // If we're dealing with an array type, decay to the pointer. if (Ty->isArrayType()) Ty = SemaRef.Context.getArrayDecayedType(Ty); // Otherwise, we don't care about qualifiers on the type. Ty = Ty.getLocalUnqualifiedType(); // Flag if we ever add a non-record type. const RecordType *TyRec = Ty->getAs(); HasNonRecordTypes = HasNonRecordTypes || !TyRec; // Flag if we encounter an arithmetic type. HasArithmeticOrEnumeralTypes = HasArithmeticOrEnumeralTypes || Ty->isArithmeticType(); if (Ty->isObjCIdType() || Ty->isObjCClassType()) PointerTypes.insert(Ty); else if (Ty->getAs() || Ty->getAs()) { // Insert our type, and its more-qualified variants, into the set // of types. if (!AddPointerWithMoreQualifiedTypeVariants(Ty, VisibleQuals)) return; } else if (Ty->isMemberPointerType()) { // Member pointers are far easier, since the pointee can't be converted. if (!AddMemberPointerWithMoreQualifiedTypeVariants(Ty)) return; } else if (Ty->isEnumeralType()) { HasArithmeticOrEnumeralTypes = true; EnumerationTypes.insert(Ty); } else if (Ty->isVectorType()) { // We treat vector types as arithmetic types in many contexts as an // extension. HasArithmeticOrEnumeralTypes = true; VectorTypes.insert(Ty); } else if (Ty->isMatrixType()) { // Similar to vector types, we treat vector types as arithmetic types in // many contexts as an extension. HasArithmeticOrEnumeralTypes = true; MatrixTypes.insert(Ty); } else if (Ty->isNullPtrType()) { HasNullPtrType = true; } else if (AllowUserConversions && TyRec) { // No conversion functions in incomplete types. if (!SemaRef.isCompleteType(Loc, Ty)) return; CXXRecordDecl *ClassDecl = cast(TyRec->getDecl()); for (NamedDecl *D : ClassDecl->getVisibleConversionFunctions()) { if (isa(D)) D = cast(D)->getTargetDecl(); // Skip conversion function templates; they don't tell us anything // about which builtin types we can convert to. if (isa(D)) continue; CXXConversionDecl *Conv = cast(D); if (AllowExplicitConversions || !Conv->isExplicit()) { AddTypesConvertedFrom(Conv->getConversionType(), Loc, false, false, VisibleQuals); } } } } /// Helper function for adjusting address spaces for the pointer or reference /// operands of builtin operators depending on the argument. static QualType AdjustAddressSpaceForBuiltinOperandType(Sema &S, QualType T, Expr *Arg) { return S.Context.getAddrSpaceQualType(T, Arg->getType().getAddressSpace()); } /// Helper function for AddBuiltinOperatorCandidates() that adds /// the volatile- and non-volatile-qualified assignment operators for the /// given type to the candidate set. static void AddBuiltinAssignmentOperatorCandidates(Sema &S, QualType T, ArrayRef Args, OverloadCandidateSet &CandidateSet) { QualType ParamTypes[2]; // T& operator=(T&, T) ParamTypes[0] = S.Context.getLValueReferenceType( AdjustAddressSpaceForBuiltinOperandType(S, T, Args[0])); ParamTypes[1] = T; S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet, /*IsAssignmentOperator=*/true); if (!S.Context.getCanonicalType(T).isVolatileQualified()) { // volatile T& operator=(volatile T&, T) ParamTypes[0] = S.Context.getLValueReferenceType( AdjustAddressSpaceForBuiltinOperandType(S, S.Context.getVolatileType(T), Args[0])); ParamTypes[1] = T; S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet, /*IsAssignmentOperator=*/true); } } /// CollectVRQualifiers - This routine returns Volatile/Restrict qualifiers, /// if any, found in visible type conversion functions found in ArgExpr's type. static Qualifiers CollectVRQualifiers(ASTContext &Context, Expr* ArgExpr) { Qualifiers VRQuals; const RecordType *TyRec; if (const MemberPointerType *RHSMPType = ArgExpr->getType()->getAs()) TyRec = RHSMPType->getClass()->getAs(); else TyRec = ArgExpr->getType()->getAs(); if (!TyRec) { // Just to be safe, assume the worst case. VRQuals.addVolatile(); VRQuals.addRestrict(); return VRQuals; } CXXRecordDecl *ClassDecl = cast(TyRec->getDecl()); if (!ClassDecl->hasDefinition()) return VRQuals; for (NamedDecl *D : ClassDecl->getVisibleConversionFunctions()) { if (isa(D)) D = cast(D)->getTargetDecl(); if (CXXConversionDecl *Conv = dyn_cast(D)) { QualType CanTy = Context.getCanonicalType(Conv->getConversionType()); if (const ReferenceType *ResTypeRef = CanTy->getAs()) CanTy = ResTypeRef->getPointeeType(); // Need to go down the pointer/mempointer chain and add qualifiers // as see them. bool done = false; while (!done) { if (CanTy.isRestrictQualified()) VRQuals.addRestrict(); if (const PointerType *ResTypePtr = CanTy->getAs()) CanTy = ResTypePtr->getPointeeType(); else if (const MemberPointerType *ResTypeMPtr = CanTy->getAs()) CanTy = ResTypeMPtr->getPointeeType(); else done = true; if (CanTy.isVolatileQualified()) VRQuals.addVolatile(); if (VRQuals.hasRestrict() && VRQuals.hasVolatile()) return VRQuals; } } } return VRQuals; } namespace { /// Helper class to manage the addition of builtin operator overload /// candidates. It provides shared state and utility methods used throughout /// the process, as well as a helper method to add each group of builtin /// operator overloads from the standard to a candidate set. class BuiltinOperatorOverloadBuilder { // Common instance state available to all overload candidate addition methods. Sema &S; ArrayRef Args; Qualifiers VisibleTypeConversionsQuals; bool HasArithmeticOrEnumeralCandidateType; SmallVectorImpl &CandidateTypes; OverloadCandidateSet &CandidateSet; static constexpr int ArithmeticTypesCap = 24; SmallVector ArithmeticTypes; // Define some indices used to iterate over the arithmetic types in // ArithmeticTypes. The "promoted arithmetic types" are the arithmetic // types are that preserved by promotion (C++ [over.built]p2). unsigned FirstIntegralType, LastIntegralType; unsigned FirstPromotedIntegralType, LastPromotedIntegralType; unsigned FirstPromotedArithmeticType, LastPromotedArithmeticType; unsigned NumArithmeticTypes; void InitArithmeticTypes() { // Start of promoted types. FirstPromotedArithmeticType = 0; ArithmeticTypes.push_back(S.Context.FloatTy); ArithmeticTypes.push_back(S.Context.DoubleTy); ArithmeticTypes.push_back(S.Context.LongDoubleTy); if (S.Context.getTargetInfo().hasFloat128Type()) ArithmeticTypes.push_back(S.Context.Float128Ty); // Start of integral types. FirstIntegralType = ArithmeticTypes.size(); FirstPromotedIntegralType = ArithmeticTypes.size(); ArithmeticTypes.push_back(S.Context.IntTy); ArithmeticTypes.push_back(S.Context.LongTy); ArithmeticTypes.push_back(S.Context.LongLongTy); if (S.Context.getTargetInfo().hasInt128Type() || (S.Context.getAuxTargetInfo() && S.Context.getAuxTargetInfo()->hasInt128Type())) ArithmeticTypes.push_back(S.Context.Int128Ty); ArithmeticTypes.push_back(S.Context.UnsignedIntTy); ArithmeticTypes.push_back(S.Context.UnsignedLongTy); ArithmeticTypes.push_back(S.Context.UnsignedLongLongTy); if (S.Context.getTargetInfo().hasInt128Type() || (S.Context.getAuxTargetInfo() && S.Context.getAuxTargetInfo()->hasInt128Type())) ArithmeticTypes.push_back(S.Context.UnsignedInt128Ty); LastPromotedIntegralType = ArithmeticTypes.size(); LastPromotedArithmeticType = ArithmeticTypes.size(); // End of promoted types. ArithmeticTypes.push_back(S.Context.BoolTy); ArithmeticTypes.push_back(S.Context.CharTy); ArithmeticTypes.push_back(S.Context.WCharTy); if (S.Context.getLangOpts().Char8) ArithmeticTypes.push_back(S.Context.Char8Ty); ArithmeticTypes.push_back(S.Context.Char16Ty); ArithmeticTypes.push_back(S.Context.Char32Ty); ArithmeticTypes.push_back(S.Context.SignedCharTy); ArithmeticTypes.push_back(S.Context.ShortTy); ArithmeticTypes.push_back(S.Context.UnsignedCharTy); ArithmeticTypes.push_back(S.Context.UnsignedShortTy); LastIntegralType = ArithmeticTypes.size(); NumArithmeticTypes = ArithmeticTypes.size(); // End of integral types. // FIXME: What about complex? What about half? assert(ArithmeticTypes.size() <= ArithmeticTypesCap && "Enough inline storage for all arithmetic types."); } /// Helper method to factor out the common pattern of adding overloads /// for '++' and '--' builtin operators. void addPlusPlusMinusMinusStyleOverloads(QualType CandidateTy, bool HasVolatile, bool HasRestrict) { QualType ParamTypes[2] = { S.Context.getLValueReferenceType(CandidateTy), S.Context.IntTy }; // Non-volatile version. S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet); // Use a heuristic to reduce number of builtin candidates in the set: // add volatile version only if there are conversions to a volatile type. if (HasVolatile) { ParamTypes[0] = S.Context.getLValueReferenceType( S.Context.getVolatileType(CandidateTy)); S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet); } // Add restrict version only if there are conversions to a restrict type // and our candidate type is a non-restrict-qualified pointer. if (HasRestrict && CandidateTy->isAnyPointerType() && !CandidateTy.isRestrictQualified()) { ParamTypes[0] = S.Context.getLValueReferenceType( S.Context.getCVRQualifiedType(CandidateTy, Qualifiers::Restrict)); S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet); if (HasVolatile) { ParamTypes[0] = S.Context.getLValueReferenceType( S.Context.getCVRQualifiedType(CandidateTy, (Qualifiers::Volatile | Qualifiers::Restrict))); S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet); } } } /// Helper to add an overload candidate for a binary builtin with types \p L /// and \p R. void AddCandidate(QualType L, QualType R) { QualType LandR[2] = {L, R}; S.AddBuiltinCandidate(LandR, Args, CandidateSet); } public: BuiltinOperatorOverloadBuilder( Sema &S, ArrayRef Args, Qualifiers VisibleTypeConversionsQuals, bool HasArithmeticOrEnumeralCandidateType, SmallVectorImpl &CandidateTypes, OverloadCandidateSet &CandidateSet) : S(S), Args(Args), VisibleTypeConversionsQuals(VisibleTypeConversionsQuals), HasArithmeticOrEnumeralCandidateType( HasArithmeticOrEnumeralCandidateType), CandidateTypes(CandidateTypes), CandidateSet(CandidateSet) { InitArithmeticTypes(); } // Increment is deprecated for bool since C++17. // // C++ [over.built]p3: // // For every pair (T, VQ), where T is an arithmetic type other // than bool, and VQ is either volatile or empty, there exist // candidate operator functions of the form // // VQ T& operator++(VQ T&); // T operator++(VQ T&, int); // // C++ [over.built]p4: // // For every pair (T, VQ), where T is an arithmetic type other // than bool, and VQ is either volatile or empty, there exist // candidate operator functions of the form // // VQ T& operator--(VQ T&); // T operator--(VQ T&, int); void addPlusPlusMinusMinusArithmeticOverloads(OverloadedOperatorKind Op) { if (!HasArithmeticOrEnumeralCandidateType) return; for (unsigned Arith = 0; Arith < NumArithmeticTypes; ++Arith) { const auto TypeOfT = ArithmeticTypes[Arith]; if (TypeOfT == S.Context.BoolTy) { if (Op == OO_MinusMinus) continue; if (Op == OO_PlusPlus && S.getLangOpts().CPlusPlus17) continue; } addPlusPlusMinusMinusStyleOverloads( TypeOfT, VisibleTypeConversionsQuals.hasVolatile(), VisibleTypeConversionsQuals.hasRestrict()); } } // C++ [over.built]p5: // // For every pair (T, VQ), where T is a cv-qualified or // cv-unqualified object type, and VQ is either volatile or // empty, there exist candidate operator functions of the form // // T*VQ& operator++(T*VQ&); // T*VQ& operator--(T*VQ&); // T* operator++(T*VQ&, int); // T* operator--(T*VQ&, int); void addPlusPlusMinusMinusPointerOverloads() { for (QualType PtrTy : CandidateTypes[0].pointer_types()) { // Skip pointer types that aren't pointers to object types. if (!PtrTy->getPointeeType()->isObjectType()) continue; addPlusPlusMinusMinusStyleOverloads( PtrTy, (!PtrTy.isVolatileQualified() && VisibleTypeConversionsQuals.hasVolatile()), (!PtrTy.isRestrictQualified() && VisibleTypeConversionsQuals.hasRestrict())); } } // C++ [over.built]p6: // For every cv-qualified or cv-unqualified object type T, there // exist candidate operator functions of the form // // T& operator*(T*); // // C++ [over.built]p7: // For every function type T that does not have cv-qualifiers or a // ref-qualifier, there exist candidate operator functions of the form // T& operator*(T*); void addUnaryStarPointerOverloads() { for (QualType ParamTy : CandidateTypes[0].pointer_types()) { QualType PointeeTy = ParamTy->getPointeeType(); if (!PointeeTy->isObjectType() && !PointeeTy->isFunctionType()) continue; if (const FunctionProtoType *Proto =PointeeTy->getAs()) if (Proto->getMethodQuals() || Proto->getRefQualifier()) continue; S.AddBuiltinCandidate(&ParamTy, Args, CandidateSet); } } // C++ [over.built]p9: // For every promoted arithmetic type T, there exist candidate // operator functions of the form // // T operator+(T); // T operator-(T); void addUnaryPlusOrMinusArithmeticOverloads() { if (!HasArithmeticOrEnumeralCandidateType) return; for (unsigned Arith = FirstPromotedArithmeticType; Arith < LastPromotedArithmeticType; ++Arith) { QualType ArithTy = ArithmeticTypes[Arith]; S.AddBuiltinCandidate(&ArithTy, Args, CandidateSet); } // Extension: We also add these operators for vector types. for (QualType VecTy : CandidateTypes[0].vector_types()) S.AddBuiltinCandidate(&VecTy, Args, CandidateSet); } // C++ [over.built]p8: // For every type T, there exist candidate operator functions of // the form // // T* operator+(T*); void addUnaryPlusPointerOverloads() { for (QualType ParamTy : CandidateTypes[0].pointer_types()) S.AddBuiltinCandidate(&ParamTy, Args, CandidateSet); } // C++ [over.built]p10: // For every promoted integral type T, there exist candidate // operator functions of the form // // T operator~(T); void addUnaryTildePromotedIntegralOverloads() { if (!HasArithmeticOrEnumeralCandidateType) return; for (unsigned Int = FirstPromotedIntegralType; Int < LastPromotedIntegralType; ++Int) { QualType IntTy = ArithmeticTypes[Int]; S.AddBuiltinCandidate(&IntTy, Args, CandidateSet); } // Extension: We also add this operator for vector types. for (QualType VecTy : CandidateTypes[0].vector_types()) S.AddBuiltinCandidate(&VecTy, Args, CandidateSet); } // C++ [over.match.oper]p16: // For every pointer to member type T or type std::nullptr_t, there // exist candidate operator functions of the form // // bool operator==(T,T); // bool operator!=(T,T); void addEqualEqualOrNotEqualMemberPointerOrNullptrOverloads() { /// Set of (canonical) types that we've already handled. llvm::SmallPtrSet AddedTypes; for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) { for (QualType MemPtrTy : CandidateTypes[ArgIdx].member_pointer_types()) { // Don't add the same builtin candidate twice. if (!AddedTypes.insert(S.Context.getCanonicalType(MemPtrTy)).second) continue; QualType ParamTypes[2] = {MemPtrTy, MemPtrTy}; S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet); } if (CandidateTypes[ArgIdx].hasNullPtrType()) { CanQualType NullPtrTy = S.Context.getCanonicalType(S.Context.NullPtrTy); if (AddedTypes.insert(NullPtrTy).second) { QualType ParamTypes[2] = { NullPtrTy, NullPtrTy }; S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet); } } } } // C++ [over.built]p15: // // For every T, where T is an enumeration type or a pointer type, // there exist candidate operator functions of the form // // bool operator<(T, T); // bool operator>(T, T); // bool operator<=(T, T); // bool operator>=(T, T); // bool operator==(T, T); // bool operator!=(T, T); // R operator<=>(T, T) void addGenericBinaryPointerOrEnumeralOverloads() { // C++ [over.match.oper]p3: // [...]the built-in candidates include all of the candidate operator // functions defined in 13.6 that, compared to the given operator, [...] // do not have the same parameter-type-list as any non-template non-member // candidate. // // Note that in practice, this only affects enumeration types because there // aren't any built-in candidates of record type, and a user-defined operator // must have an operand of record or enumeration type. Also, the only other // overloaded operator with enumeration arguments, operator=, // cannot be overloaded for enumeration types, so this is the only place // where we must suppress candidates like this. llvm::DenseSet > UserDefinedBinaryOperators; for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) { if (!CandidateTypes[ArgIdx].enumeration_types().empty()) { for (OverloadCandidateSet::iterator C = CandidateSet.begin(), CEnd = CandidateSet.end(); C != CEnd; ++C) { if (!C->Viable || !C->Function || C->Function->getNumParams() != 2) continue; if (C->Function->isFunctionTemplateSpecialization()) continue; // We interpret "same parameter-type-list" as applying to the // "synthesized candidate, with the order of the two parameters // reversed", not to the original function. bool Reversed = C->isReversed(); QualType FirstParamType = C->Function->getParamDecl(Reversed ? 1 : 0) ->getType() .getUnqualifiedType(); QualType SecondParamType = C->Function->getParamDecl(Reversed ? 0 : 1) ->getType() .getUnqualifiedType(); // Skip if either parameter isn't of enumeral type. if (!FirstParamType->isEnumeralType() || !SecondParamType->isEnumeralType()) continue; // Add this operator to the set of known user-defined operators. UserDefinedBinaryOperators.insert( std::make_pair(S.Context.getCanonicalType(FirstParamType), S.Context.getCanonicalType(SecondParamType))); } } } /// Set of (canonical) types that we've already handled. llvm::SmallPtrSet AddedTypes; for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) { for (QualType PtrTy : CandidateTypes[ArgIdx].pointer_types()) { // Don't add the same builtin candidate twice. if (!AddedTypes.insert(S.Context.getCanonicalType(PtrTy)).second) continue; QualType ParamTypes[2] = {PtrTy, PtrTy}; S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet); } for (QualType EnumTy : CandidateTypes[ArgIdx].enumeration_types()) { CanQualType CanonType = S.Context.getCanonicalType(EnumTy); // Don't add the same builtin candidate twice, or if a user defined // candidate exists. if (!AddedTypes.insert(CanonType).second || UserDefinedBinaryOperators.count(std::make_pair(CanonType, CanonType))) continue; QualType ParamTypes[2] = {EnumTy, EnumTy}; S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet); } } } // C++ [over.built]p13: // // For every cv-qualified or cv-unqualified object type T // there exist candidate operator functions of the form // // T* operator+(T*, ptrdiff_t); // T& operator[](T*, ptrdiff_t); [BELOW] // T* operator-(T*, ptrdiff_t); // T* operator+(ptrdiff_t, T*); // T& operator[](ptrdiff_t, T*); [BELOW] // // C++ [over.built]p14: // // For every T, where T is a pointer to object type, there // exist candidate operator functions of the form // // ptrdiff_t operator-(T, T); void addBinaryPlusOrMinusPointerOverloads(OverloadedOperatorKind Op) { /// Set of (canonical) types that we've already handled. llvm::SmallPtrSet AddedTypes; for (int Arg = 0; Arg < 2; ++Arg) { QualType AsymmetricParamTypes[2] = { S.Context.getPointerDiffType(), S.Context.getPointerDiffType(), }; for (QualType PtrTy : CandidateTypes[Arg].pointer_types()) { QualType PointeeTy = PtrTy->getPointeeType(); if (!PointeeTy->isObjectType()) continue; AsymmetricParamTypes[Arg] = PtrTy; if (Arg == 0 || Op == OO_Plus) { // operator+(T*, ptrdiff_t) or operator-(T*, ptrdiff_t) // T* operator+(ptrdiff_t, T*); S.AddBuiltinCandidate(AsymmetricParamTypes, Args, CandidateSet); } if (Op == OO_Minus) { // ptrdiff_t operator-(T, T); if (!AddedTypes.insert(S.Context.getCanonicalType(PtrTy)).second) continue; QualType ParamTypes[2] = {PtrTy, PtrTy}; S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet); } } } } // C++ [over.built]p12: // // For every pair of promoted arithmetic types L and R, there // exist candidate operator functions of the form // // LR operator*(L, R); // LR operator/(L, R); // LR operator+(L, R); // LR operator-(L, R); // bool operator<(L, R); // bool operator>(L, R); // bool operator<=(L, R); // bool operator>=(L, R); // bool operator==(L, R); // bool operator!=(L, R); // // where LR is the result of the usual arithmetic conversions // between types L and R. // // C++ [over.built]p24: // // For every pair of promoted arithmetic types L and R, there exist // candidate operator functions of the form // // LR operator?(bool, L, R); // // where LR is the result of the usual arithmetic conversions // between types L and R. // Our candidates ignore the first parameter. void addGenericBinaryArithmeticOverloads() { if (!HasArithmeticOrEnumeralCandidateType) return; for (unsigned Left = FirstPromotedArithmeticType; Left < LastPromotedArithmeticType; ++Left) { for (unsigned Right = FirstPromotedArithmeticType; Right < LastPromotedArithmeticType; ++Right) { QualType LandR[2] = { ArithmeticTypes[Left], ArithmeticTypes[Right] }; S.AddBuiltinCandidate(LandR, Args, CandidateSet); } } // Extension: Add the binary operators ==, !=, <, <=, >=, >, *, /, and the // conditional operator for vector types. for (QualType Vec1Ty : CandidateTypes[0].vector_types()) for (QualType Vec2Ty : CandidateTypes[1].vector_types()) { QualType LandR[2] = {Vec1Ty, Vec2Ty}; S.AddBuiltinCandidate(LandR, Args, CandidateSet); } } /// Add binary operator overloads for each candidate matrix type M1, M2: /// * (M1, M1) -> M1 /// * (M1, M1.getElementType()) -> M1 /// * (M2.getElementType(), M2) -> M2 /// * (M2, M2) -> M2 // Only if M2 is not part of CandidateTypes[0]. void addMatrixBinaryArithmeticOverloads() { if (!HasArithmeticOrEnumeralCandidateType) return; for (QualType M1 : CandidateTypes[0].matrix_types()) { AddCandidate(M1, cast(M1)->getElementType()); AddCandidate(M1, M1); } for (QualType M2 : CandidateTypes[1].matrix_types()) { AddCandidate(cast(M2)->getElementType(), M2); if (!CandidateTypes[0].containsMatrixType(M2)) AddCandidate(M2, M2); } } // C++2a [over.built]p14: // // For every integral type T there exists a candidate operator function // of the form // // std::strong_ordering operator<=>(T, T) // // C++2a [over.built]p15: // // For every pair of floating-point types L and R, there exists a candidate // operator function of the form // // std::partial_ordering operator<=>(L, R); // // FIXME: The current specification for integral types doesn't play nice with // the direction of p0946r0, which allows mixed integral and unscoped-enum // comparisons. Under the current spec this can lead to ambiguity during // overload resolution. For example: // // enum A : int {a}; // auto x = (a <=> (long)42); // // error: call is ambiguous for arguments 'A' and 'long'. // note: candidate operator<=>(int, int) // note: candidate operator<=>(long, long) // // To avoid this error, this function deviates from the specification and adds // the mixed overloads `operator<=>(L, R)` where L and R are promoted // arithmetic types (the same as the generic relational overloads). // // For now this function acts as a placeholder. void addThreeWayArithmeticOverloads() { addGenericBinaryArithmeticOverloads(); } // C++ [over.built]p17: // // For every pair of promoted integral types L and R, there // exist candidate operator functions of the form // // LR operator%(L, R); // LR operator&(L, R); // LR operator^(L, R); // LR operator|(L, R); // L operator<<(L, R); // L operator>>(L, R); // // where LR is the result of the usual arithmetic conversions // between types L and R. void addBinaryBitwiseArithmeticOverloads(OverloadedOperatorKind Op) { if (!HasArithmeticOrEnumeralCandidateType) return; for (unsigned Left = FirstPromotedIntegralType; Left < LastPromotedIntegralType; ++Left) { for (unsigned Right = FirstPromotedIntegralType; Right < LastPromotedIntegralType; ++Right) { QualType LandR[2] = { ArithmeticTypes[Left], ArithmeticTypes[Right] }; S.AddBuiltinCandidate(LandR, Args, CandidateSet); } } } // C++ [over.built]p20: // // For every pair (T, VQ), where T is an enumeration or // pointer to member type and VQ is either volatile or // empty, there exist candidate operator functions of the form // // VQ T& operator=(VQ T&, T); void addAssignmentMemberPointerOrEnumeralOverloads() { /// Set of (canonical) types that we've already handled. llvm::SmallPtrSet AddedTypes; for (unsigned ArgIdx = 0; ArgIdx < 2; ++ArgIdx) { for (QualType EnumTy : CandidateTypes[ArgIdx].enumeration_types()) { if (!AddedTypes.insert(S.Context.getCanonicalType(EnumTy)).second) continue; AddBuiltinAssignmentOperatorCandidates(S, EnumTy, Args, CandidateSet); } for (QualType MemPtrTy : CandidateTypes[ArgIdx].member_pointer_types()) { if (!AddedTypes.insert(S.Context.getCanonicalType(MemPtrTy)).second) continue; AddBuiltinAssignmentOperatorCandidates(S, MemPtrTy, Args, CandidateSet); } } } // C++ [over.built]p19: // // For every pair (T, VQ), where T is any type and VQ is either // volatile or empty, there exist candidate operator functions // of the form // // T*VQ& operator=(T*VQ&, T*); // // C++ [over.built]p21: // // For every pair (T, VQ), where T is a cv-qualified or // cv-unqualified object type and VQ is either volatile or // empty, there exist candidate operator functions of the form // // T*VQ& operator+=(T*VQ&, ptrdiff_t); // T*VQ& operator-=(T*VQ&, ptrdiff_t); void addAssignmentPointerOverloads(bool isEqualOp) { /// Set of (canonical) types that we've already handled. llvm::SmallPtrSet AddedTypes; for (QualType PtrTy : CandidateTypes[0].pointer_types()) { // If this is operator=, keep track of the builtin candidates we added. if (isEqualOp) AddedTypes.insert(S.Context.getCanonicalType(PtrTy)); else if (!PtrTy->getPointeeType()->isObjectType()) continue; // non-volatile version QualType ParamTypes[2] = { S.Context.getLValueReferenceType(PtrTy), isEqualOp ? PtrTy : S.Context.getPointerDiffType(), }; S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet, /*IsAssignmentOperator=*/ isEqualOp); bool NeedVolatile = !PtrTy.isVolatileQualified() && VisibleTypeConversionsQuals.hasVolatile(); if (NeedVolatile) { // volatile version ParamTypes[0] = S.Context.getLValueReferenceType(S.Context.getVolatileType(PtrTy)); S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet, /*IsAssignmentOperator=*/isEqualOp); } if (!PtrTy.isRestrictQualified() && VisibleTypeConversionsQuals.hasRestrict()) { // restrict version ParamTypes[0] = S.Context.getLValueReferenceType(S.Context.getRestrictType(PtrTy)); S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet, /*IsAssignmentOperator=*/isEqualOp); if (NeedVolatile) { // volatile restrict version ParamTypes[0] = S.Context.getLValueReferenceType(S.Context.getCVRQualifiedType( PtrTy, (Qualifiers::Volatile | Qualifiers::Restrict))); S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet, /*IsAssignmentOperator=*/isEqualOp); } } } if (isEqualOp) { for (QualType PtrTy : CandidateTypes[1].pointer_types()) { // Make sure we don't add the same candidate twice. if (!AddedTypes.insert(S.Context.getCanonicalType(PtrTy)).second) continue; QualType ParamTypes[2] = { S.Context.getLValueReferenceType(PtrTy), PtrTy, }; // non-volatile version S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet, /*IsAssignmentOperator=*/true); bool NeedVolatile = !PtrTy.isVolatileQualified() && VisibleTypeConversionsQuals.hasVolatile(); if (NeedVolatile) { // volatile version ParamTypes[0] = S.Context.getLValueReferenceType( S.Context.getVolatileType(PtrTy)); S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet, /*IsAssignmentOperator=*/true); } if (!PtrTy.isRestrictQualified() && VisibleTypeConversionsQuals.hasRestrict()) { // restrict version ParamTypes[0] = S.Context.getLValueReferenceType( S.Context.getRestrictType(PtrTy)); S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet, /*IsAssignmentOperator=*/true); if (NeedVolatile) { // volatile restrict version ParamTypes[0] = S.Context.getLValueReferenceType(S.Context.getCVRQualifiedType( PtrTy, (Qualifiers::Volatile | Qualifiers::Restrict))); S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet, /*IsAssignmentOperator=*/true); } } } } } // C++ [over.built]p18: // // For every triple (L, VQ, R), where L is an arithmetic type, // VQ is either volatile or empty, and R is a promoted // arithmetic type, there exist candidate operator functions of // the form // // VQ L& operator=(VQ L&, R); // VQ L& operator*=(VQ L&, R); // VQ L& operator/=(VQ L&, R); // VQ L& operator+=(VQ L&, R); // VQ L& operator-=(VQ L&, R); void addAssignmentArithmeticOverloads(bool isEqualOp) { if (!HasArithmeticOrEnumeralCandidateType) return; for (unsigned Left = 0; Left < NumArithmeticTypes; ++Left) { for (unsigned Right = FirstPromotedArithmeticType; Right < LastPromotedArithmeticType; ++Right) { QualType ParamTypes[2]; ParamTypes[1] = ArithmeticTypes[Right]; auto LeftBaseTy = AdjustAddressSpaceForBuiltinOperandType( S, ArithmeticTypes[Left], Args[0]); // Add this built-in operator as a candidate (VQ is empty). ParamTypes[0] = S.Context.getLValueReferenceType(LeftBaseTy); S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet, /*IsAssignmentOperator=*/isEqualOp); // Add this built-in operator as a candidate (VQ is 'volatile'). if (VisibleTypeConversionsQuals.hasVolatile()) { ParamTypes[0] = S.Context.getVolatileType(LeftBaseTy); ParamTypes[0] = S.Context.getLValueReferenceType(ParamTypes[0]); S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet, /*IsAssignmentOperator=*/isEqualOp); } } } // Extension: Add the binary operators =, +=, -=, *=, /= for vector types. for (QualType Vec1Ty : CandidateTypes[0].vector_types()) for (QualType Vec2Ty : CandidateTypes[0].vector_types()) { QualType ParamTypes[2]; ParamTypes[1] = Vec2Ty; // Add this built-in operator as a candidate (VQ is empty). ParamTypes[0] = S.Context.getLValueReferenceType(Vec1Ty); S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet, /*IsAssignmentOperator=*/isEqualOp); // Add this built-in operator as a candidate (VQ is 'volatile'). if (VisibleTypeConversionsQuals.hasVolatile()) { ParamTypes[0] = S.Context.getVolatileType(Vec1Ty); ParamTypes[0] = S.Context.getLValueReferenceType(ParamTypes[0]); S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet, /*IsAssignmentOperator=*/isEqualOp); } } } // C++ [over.built]p22: // // For every triple (L, VQ, R), where L is an integral type, VQ // is either volatile or empty, and R is a promoted integral // type, there exist candidate operator functions of the form // // VQ L& operator%=(VQ L&, R); // VQ L& operator<<=(VQ L&, R); // VQ L& operator>>=(VQ L&, R); // VQ L& operator&=(VQ L&, R); // VQ L& operator^=(VQ L&, R); // VQ L& operator|=(VQ L&, R); void addAssignmentIntegralOverloads() { if (!HasArithmeticOrEnumeralCandidateType) return; for (unsigned Left = FirstIntegralType; Left < LastIntegralType; ++Left) { for (unsigned Right = FirstPromotedIntegralType; Right < LastPromotedIntegralType; ++Right) { QualType ParamTypes[2]; ParamTypes[1] = ArithmeticTypes[Right]; auto LeftBaseTy = AdjustAddressSpaceForBuiltinOperandType( S, ArithmeticTypes[Left], Args[0]); // Add this built-in operator as a candidate (VQ is empty). ParamTypes[0] = S.Context.getLValueReferenceType(LeftBaseTy); S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet); if (VisibleTypeConversionsQuals.hasVolatile()) { // Add this built-in operator as a candidate (VQ is 'volatile'). ParamTypes[0] = LeftBaseTy; ParamTypes[0] = S.Context.getVolatileType(ParamTypes[0]); ParamTypes[0] = S.Context.getLValueReferenceType(ParamTypes[0]); S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet); } } } } // C++ [over.operator]p23: // // There also exist candidate operator functions of the form // // bool operator!(bool); // bool operator&&(bool, bool); // bool operator||(bool, bool); void addExclaimOverload() { QualType ParamTy = S.Context.BoolTy; S.AddBuiltinCandidate(&ParamTy, Args, CandidateSet, /*IsAssignmentOperator=*/false, /*NumContextualBoolArguments=*/1); } void addAmpAmpOrPipePipeOverload() { QualType ParamTypes[2] = { S.Context.BoolTy, S.Context.BoolTy }; S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet, /*IsAssignmentOperator=*/false, /*NumContextualBoolArguments=*/2); } // C++ [over.built]p13: // // For every cv-qualified or cv-unqualified object type T there // exist candidate operator functions of the form // // T* operator+(T*, ptrdiff_t); [ABOVE] // T& operator[](T*, ptrdiff_t); // T* operator-(T*, ptrdiff_t); [ABOVE] // T* operator+(ptrdiff_t, T*); [ABOVE] // T& operator[](ptrdiff_t, T*); void addSubscriptOverloads() { for (QualType PtrTy : CandidateTypes[0].pointer_types()) { QualType ParamTypes[2] = {PtrTy, S.Context.getPointerDiffType()}; QualType PointeeType = PtrTy->getPointeeType(); if (!PointeeType->isObjectType()) continue; // T& operator[](T*, ptrdiff_t) S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet); } for (QualType PtrTy : CandidateTypes[1].pointer_types()) { QualType ParamTypes[2] = {S.Context.getPointerDiffType(), PtrTy}; QualType PointeeType = PtrTy->getPointeeType(); if (!PointeeType->isObjectType()) continue; // T& operator[](ptrdiff_t, T*) S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet); } } // C++ [over.built]p11: // For every quintuple (C1, C2, T, CV1, CV2), where C2 is a class type, // C1 is the same type as C2 or is a derived class of C2, T is an object // type or a function type, and CV1 and CV2 are cv-qualifier-seqs, // there exist candidate operator functions of the form // // CV12 T& operator->*(CV1 C1*, CV2 T C2::*); // // where CV12 is the union of CV1 and CV2. void addArrowStarOverloads() { for (QualType PtrTy : CandidateTypes[0].pointer_types()) { QualType C1Ty = PtrTy; QualType C1; QualifierCollector Q1; C1 = QualType(Q1.strip(C1Ty->getPointeeType()), 0); if (!isa(C1)) continue; // heuristic to reduce number of builtin candidates in the set. // Add volatile/restrict version only if there are conversions to a // volatile/restrict type. if (!VisibleTypeConversionsQuals.hasVolatile() && Q1.hasVolatile()) continue; if (!VisibleTypeConversionsQuals.hasRestrict() && Q1.hasRestrict()) continue; for (QualType MemPtrTy : CandidateTypes[1].member_pointer_types()) { const MemberPointerType *mptr = cast(MemPtrTy); QualType C2 = QualType(mptr->getClass(), 0); C2 = C2.getUnqualifiedType(); if (C1 != C2 && !S.IsDerivedFrom(CandidateSet.getLocation(), C1, C2)) break; QualType ParamTypes[2] = {PtrTy, MemPtrTy}; // build CV12 T& QualType T = mptr->getPointeeType(); if (!VisibleTypeConversionsQuals.hasVolatile() && T.isVolatileQualified()) continue; if (!VisibleTypeConversionsQuals.hasRestrict() && T.isRestrictQualified()) continue; T = Q1.apply(S.Context, T); S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet); } } } // Note that we don't consider the first argument, since it has been // contextually converted to bool long ago. The candidates below are // therefore added as binary. // // C++ [over.built]p25: // For every type T, where T is a pointer, pointer-to-member, or scoped // enumeration type, there exist candidate operator functions of the form // // T operator?(bool, T, T); // void addConditionalOperatorOverloads() { /// Set of (canonical) types that we've already handled. llvm::SmallPtrSet AddedTypes; for (unsigned ArgIdx = 0; ArgIdx < 2; ++ArgIdx) { for (QualType PtrTy : CandidateTypes[ArgIdx].pointer_types()) { if (!AddedTypes.insert(S.Context.getCanonicalType(PtrTy)).second) continue; QualType ParamTypes[2] = {PtrTy, PtrTy}; S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet); } for (QualType MemPtrTy : CandidateTypes[ArgIdx].member_pointer_types()) { if (!AddedTypes.insert(S.Context.getCanonicalType(MemPtrTy)).second) continue; QualType ParamTypes[2] = {MemPtrTy, MemPtrTy}; S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet); } if (S.getLangOpts().CPlusPlus11) { for (QualType EnumTy : CandidateTypes[ArgIdx].enumeration_types()) { if (!EnumTy->castAs()->getDecl()->isScoped()) continue; if (!AddedTypes.insert(S.Context.getCanonicalType(EnumTy)).second) continue; QualType ParamTypes[2] = {EnumTy, EnumTy}; S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet); } } } } }; } // end anonymous namespace /// AddBuiltinOperatorCandidates - Add the appropriate built-in /// operator overloads to the candidate set (C++ [over.built]), based /// on the operator @p Op and the arguments given. For example, if the /// operator is a binary '+', this routine might add "int /// operator+(int, int)" to cover integer addition. void Sema::AddBuiltinOperatorCandidates(OverloadedOperatorKind Op, SourceLocation OpLoc, ArrayRef Args, OverloadCandidateSet &CandidateSet) { // Find all of the types that the arguments can convert to, but only // if the operator we're looking at has built-in operator candidates // that make use of these types. Also record whether we encounter non-record // candidate types or either arithmetic or enumeral candidate types. Qualifiers VisibleTypeConversionsQuals; VisibleTypeConversionsQuals.addConst(); for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) VisibleTypeConversionsQuals += CollectVRQualifiers(Context, Args[ArgIdx]); bool HasNonRecordCandidateType = false; bool HasArithmeticOrEnumeralCandidateType = false; SmallVector CandidateTypes; for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) { CandidateTypes.emplace_back(*this); CandidateTypes[ArgIdx].AddTypesConvertedFrom(Args[ArgIdx]->getType(), OpLoc, true, (Op == OO_Exclaim || Op == OO_AmpAmp || Op == OO_PipePipe), VisibleTypeConversionsQuals); HasNonRecordCandidateType = HasNonRecordCandidateType || CandidateTypes[ArgIdx].hasNonRecordTypes(); HasArithmeticOrEnumeralCandidateType = HasArithmeticOrEnumeralCandidateType || CandidateTypes[ArgIdx].hasArithmeticOrEnumeralTypes(); } // Exit early when no non-record types have been added to the candidate set // for any of the arguments to the operator. // // We can't exit early for !, ||, or &&, since there we have always have // 'bool' overloads. if (!HasNonRecordCandidateType && !(Op == OO_Exclaim || Op == OO_AmpAmp || Op == OO_PipePipe)) return; // Setup an object to manage the common state for building overloads. BuiltinOperatorOverloadBuilder OpBuilder(*this, Args, VisibleTypeConversionsQuals, HasArithmeticOrEnumeralCandidateType, CandidateTypes, CandidateSet); // Dispatch over the operation to add in only those overloads which apply. switch (Op) { case OO_None: case NUM_OVERLOADED_OPERATORS: llvm_unreachable("Expected an overloaded operator"); case OO_New: case OO_Delete: case OO_Array_New: case OO_Array_Delete: case OO_Call: llvm_unreachable( "Special operators don't use AddBuiltinOperatorCandidates"); case OO_Comma: case OO_Arrow: case OO_Coawait: // C++ [over.match.oper]p3: // -- For the operator ',', the unary operator '&', the // operator '->', or the operator 'co_await', the // built-in candidates set is empty. break; case OO_Plus: // '+' is either unary or binary if (Args.size() == 1) OpBuilder.addUnaryPlusPointerOverloads(); LLVM_FALLTHROUGH; case OO_Minus: // '-' is either unary or binary if (Args.size() == 1) { OpBuilder.addUnaryPlusOrMinusArithmeticOverloads(); } else { OpBuilder.addBinaryPlusOrMinusPointerOverloads(Op); OpBuilder.addGenericBinaryArithmeticOverloads(); OpBuilder.addMatrixBinaryArithmeticOverloads(); } break; case OO_Star: // '*' is either unary or binary if (Args.size() == 1) OpBuilder.addUnaryStarPointerOverloads(); else { OpBuilder.addGenericBinaryArithmeticOverloads(); OpBuilder.addMatrixBinaryArithmeticOverloads(); } break; case OO_Slash: OpBuilder.addGenericBinaryArithmeticOverloads(); break; case OO_PlusPlus: case OO_MinusMinus: OpBuilder.addPlusPlusMinusMinusArithmeticOverloads(Op); OpBuilder.addPlusPlusMinusMinusPointerOverloads(); break; case OO_EqualEqual: case OO_ExclaimEqual: OpBuilder.addEqualEqualOrNotEqualMemberPointerOrNullptrOverloads(); LLVM_FALLTHROUGH; case OO_Less: case OO_Greater: case OO_LessEqual: case OO_GreaterEqual: OpBuilder.addGenericBinaryPointerOrEnumeralOverloads(); OpBuilder.addGenericBinaryArithmeticOverloads(); break; case OO_Spaceship: OpBuilder.addGenericBinaryPointerOrEnumeralOverloads(); OpBuilder.addThreeWayArithmeticOverloads(); break; case OO_Percent: case OO_Caret: case OO_Pipe: case OO_LessLess: case OO_GreaterGreater: OpBuilder.addBinaryBitwiseArithmeticOverloads(Op); break; case OO_Amp: // '&' is either unary or binary if (Args.size() == 1) // C++ [over.match.oper]p3: // -- For the operator ',', the unary operator '&', or the // operator '->', the built-in candidates set is empty. break; OpBuilder.addBinaryBitwiseArithmeticOverloads(Op); break; case OO_Tilde: OpBuilder.addUnaryTildePromotedIntegralOverloads(); break; case OO_Equal: OpBuilder.addAssignmentMemberPointerOrEnumeralOverloads(); LLVM_FALLTHROUGH; case OO_PlusEqual: case OO_MinusEqual: OpBuilder.addAssignmentPointerOverloads(Op == OO_Equal); LLVM_FALLTHROUGH; case OO_StarEqual: case OO_SlashEqual: OpBuilder.addAssignmentArithmeticOverloads(Op == OO_Equal); break; case OO_PercentEqual: case OO_LessLessEqual: case OO_GreaterGreaterEqual: case OO_AmpEqual: case OO_CaretEqual: case OO_PipeEqual: OpBuilder.addAssignmentIntegralOverloads(); break; case OO_Exclaim: OpBuilder.addExclaimOverload(); break; case OO_AmpAmp: case OO_PipePipe: OpBuilder.addAmpAmpOrPipePipeOverload(); break; case OO_Subscript: OpBuilder.addSubscriptOverloads(); break; case OO_ArrowStar: OpBuilder.addArrowStarOverloads(); break; case OO_Conditional: OpBuilder.addConditionalOperatorOverloads(); OpBuilder.addGenericBinaryArithmeticOverloads(); break; } } /// Add function candidates found via argument-dependent lookup /// to the set of overloading candidates. /// /// This routine performs argument-dependent name lookup based on the /// given function name (which may also be an operator name) and adds /// all of the overload candidates found by ADL to the overload /// candidate set (C++ [basic.lookup.argdep]). void Sema::AddArgumentDependentLookupCandidates(DeclarationName Name, SourceLocation Loc, ArrayRef Args, TemplateArgumentListInfo *ExplicitTemplateArgs, OverloadCandidateSet& CandidateSet, bool PartialOverloading) { ADLResult Fns; // FIXME: This approach for uniquing ADL results (and removing // redundant candidates from the set) relies on pointer-equality, // which means we need to key off the canonical decl. However, // always going back to the canonical decl might not get us the // right set of default arguments. What default arguments are // we supposed to consider on ADL candidates, anyway? // FIXME: Pass in the explicit template arguments? ArgumentDependentLookup(Name, Loc, Args, Fns); // Erase all of the candidates we already knew about. for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(), CandEnd = CandidateSet.end(); Cand != CandEnd; ++Cand) if (Cand->Function) { Fns.erase(Cand->Function); if (FunctionTemplateDecl *FunTmpl = Cand->Function->getPrimaryTemplate()) Fns.erase(FunTmpl); } // For each of the ADL candidates we found, add it to the overload // set. for (ADLResult::iterator I = Fns.begin(), E = Fns.end(); I != E; ++I) { DeclAccessPair FoundDecl = DeclAccessPair::make(*I, AS_none); if (FunctionDecl *FD = dyn_cast(*I)) { if (ExplicitTemplateArgs) continue; AddOverloadCandidate( FD, FoundDecl, Args, CandidateSet, /*SuppressUserConversions=*/false, PartialOverloading, /*AllowExplicit=*/true, /*AllowExplicitConversions=*/false, ADLCallKind::UsesADL); if (CandidateSet.getRewriteInfo().shouldAddReversed(Context, FD)) { AddOverloadCandidate( FD, FoundDecl, {Args[1], Args[0]}, CandidateSet, /*SuppressUserConversions=*/false, PartialOverloading, /*AllowExplicit=*/true, /*AllowExplicitConversions=*/false, ADLCallKind::UsesADL, None, OverloadCandidateParamOrder::Reversed); } } else { auto *FTD = cast(*I); AddTemplateOverloadCandidate( FTD, FoundDecl, ExplicitTemplateArgs, Args, CandidateSet, /*SuppressUserConversions=*/false, PartialOverloading, /*AllowExplicit=*/true, ADLCallKind::UsesADL); if (CandidateSet.getRewriteInfo().shouldAddReversed( Context, FTD->getTemplatedDecl())) { AddTemplateOverloadCandidate( FTD, FoundDecl, ExplicitTemplateArgs, {Args[1], Args[0]}, CandidateSet, /*SuppressUserConversions=*/false, PartialOverloading, /*AllowExplicit=*/true, ADLCallKind::UsesADL, OverloadCandidateParamOrder::Reversed); } } } } namespace { enum class Comparison { Equal, Better, Worse }; } /// Compares the enable_if attributes of two FunctionDecls, for the purposes of /// overload resolution. /// /// Cand1's set of enable_if attributes are said to be "better" than Cand2's iff /// Cand1's first N enable_if attributes have precisely the same conditions as /// Cand2's first N enable_if attributes (where N = the number of enable_if /// attributes on Cand2), and Cand1 has more than N enable_if attributes. /// /// Note that you can have a pair of candidates such that Cand1's enable_if /// attributes are worse than Cand2's, and Cand2's enable_if attributes are /// worse than Cand1's. static Comparison compareEnableIfAttrs(const Sema &S, const FunctionDecl *Cand1, const FunctionDecl *Cand2) { // Common case: One (or both) decls don't have enable_if attrs. bool Cand1Attr = Cand1->hasAttr(); bool Cand2Attr = Cand2->hasAttr(); if (!Cand1Attr || !Cand2Attr) { if (Cand1Attr == Cand2Attr) return Comparison::Equal; return Cand1Attr ? Comparison::Better : Comparison::Worse; } auto Cand1Attrs = Cand1->specific_attrs(); auto Cand2Attrs = Cand2->specific_attrs(); llvm::FoldingSetNodeID Cand1ID, Cand2ID; for (auto Pair : zip_longest(Cand1Attrs, Cand2Attrs)) { Optional Cand1A = std::get<0>(Pair); Optional Cand2A = std::get<1>(Pair); // It's impossible for Cand1 to be better than (or equal to) Cand2 if Cand1 // has fewer enable_if attributes than Cand2, and vice versa. if (!Cand1A) return Comparison::Worse; if (!Cand2A) return Comparison::Better; Cand1ID.clear(); Cand2ID.clear(); (*Cand1A)->getCond()->Profile(Cand1ID, S.getASTContext(), true); (*Cand2A)->getCond()->Profile(Cand2ID, S.getASTContext(), true); if (Cand1ID != Cand2ID) return Comparison::Worse; } return Comparison::Equal; } static Comparison isBetterMultiversionCandidate(const OverloadCandidate &Cand1, const OverloadCandidate &Cand2) { if (!Cand1.Function || !Cand1.Function->isMultiVersion() || !Cand2.Function || !Cand2.Function->isMultiVersion()) return Comparison::Equal; // If both are invalid, they are equal. If one of them is invalid, the other // is better. if (Cand1.Function->isInvalidDecl()) { if (Cand2.Function->isInvalidDecl()) return Comparison::Equal; return Comparison::Worse; } if (Cand2.Function->isInvalidDecl()) return Comparison::Better; // If this is a cpu_dispatch/cpu_specific multiversion situation, prefer // cpu_dispatch, else arbitrarily based on the identifiers. bool Cand1CPUDisp = Cand1.Function->hasAttr(); bool Cand2CPUDisp = Cand2.Function->hasAttr(); const auto *Cand1CPUSpec = Cand1.Function->getAttr(); const auto *Cand2CPUSpec = Cand2.Function->getAttr(); if (!Cand1CPUDisp && !Cand2CPUDisp && !Cand1CPUSpec && !Cand2CPUSpec) return Comparison::Equal; if (Cand1CPUDisp && !Cand2CPUDisp) return Comparison::Better; if (Cand2CPUDisp && !Cand1CPUDisp) return Comparison::Worse; if (Cand1CPUSpec && Cand2CPUSpec) { if (Cand1CPUSpec->cpus_size() != Cand2CPUSpec->cpus_size()) return Cand1CPUSpec->cpus_size() < Cand2CPUSpec->cpus_size() ? Comparison::Better : Comparison::Worse; std::pair FirstDiff = std::mismatch( Cand1CPUSpec->cpus_begin(), Cand1CPUSpec->cpus_end(), Cand2CPUSpec->cpus_begin(), [](const IdentifierInfo *LHS, const IdentifierInfo *RHS) { return LHS->getName() == RHS->getName(); }); assert(FirstDiff.first != Cand1CPUSpec->cpus_end() && "Two different cpu-specific versions should not have the same " "identifier list, otherwise they'd be the same decl!"); return (*FirstDiff.first)->getName() < (*FirstDiff.second)->getName() ? Comparison::Better : Comparison::Worse; } llvm_unreachable("No way to get here unless both had cpu_dispatch"); } /// Compute the type of the implicit object parameter for the given function, /// if any. Returns None if there is no implicit object parameter, and a null /// QualType if there is a 'matches anything' implicit object parameter. static Optional getImplicitObjectParamType(ASTContext &Context, const FunctionDecl *F) { if (!isa(F) || isa(F)) return llvm::None; auto *M = cast(F); // Static member functions' object parameters match all types. if (M->isStatic()) return QualType(); QualType T = M->getThisObjectType(); if (M->getRefQualifier() == RQ_RValue) return Context.getRValueReferenceType(T); return Context.getLValueReferenceType(T); } static bool haveSameParameterTypes(ASTContext &Context, const FunctionDecl *F1, const FunctionDecl *F2, unsigned NumParams) { if (declaresSameEntity(F1, F2)) return true; auto NextParam = [&](const FunctionDecl *F, unsigned &I, bool First) { if (First) { if (Optional T = getImplicitObjectParamType(Context, F)) return *T; } assert(I < F->getNumParams()); return F->getParamDecl(I++)->getType(); }; unsigned I1 = 0, I2 = 0; for (unsigned I = 0; I != NumParams; ++I) { QualType T1 = NextParam(F1, I1, I == 0); QualType T2 = NextParam(F2, I2, I == 0); if (!T1.isNull() && !T1.isNull() && !Context.hasSameUnqualifiedType(T1, T2)) return false; } return true; } /// isBetterOverloadCandidate - Determines whether the first overload /// candidate is a better candidate than the second (C++ 13.3.3p1). bool clang::isBetterOverloadCandidate( Sema &S, const OverloadCandidate &Cand1, const OverloadCandidate &Cand2, SourceLocation Loc, OverloadCandidateSet::CandidateSetKind Kind) { // Define viable functions to be better candidates than non-viable // functions. if (!Cand2.Viable) return Cand1.Viable; else if (!Cand1.Viable) return false; // [CUDA] A function with 'never' preference is marked not viable, therefore // is never shown up here. The worst preference shown up here is 'wrong side', // e.g. an H function called by a HD function in device compilation. This is // valid AST as long as the HD function is not emitted, e.g. it is an inline // function which is called only by an H function. A deferred diagnostic will // be triggered if it is emitted. However a wrong-sided function is still // a viable candidate here. // // If Cand1 can be emitted and Cand2 cannot be emitted in the current // context, Cand1 is better than Cand2. If Cand1 can not be emitted and Cand2 // can be emitted, Cand1 is not better than Cand2. This rule should have // precedence over other rules. // // If both Cand1 and Cand2 can be emitted, or neither can be emitted, then // other rules should be used to determine which is better. This is because // host/device based overloading resolution is mostly for determining // viability of a function. If two functions are both viable, other factors // should take precedence in preference, e.g. the standard-defined preferences // like argument conversion ranks or enable_if partial-ordering. The // preference for pass-object-size parameters is probably most similar to a // type-based-overloading decision and so should take priority. // // If other rules cannot determine which is better, CUDA preference will be // used again to determine which is better. // // TODO: Currently IdentifyCUDAPreference does not return correct values // for functions called in global variable initializers due to missing // correct context about device/host. Therefore we can only enforce this // rule when there is a caller. We should enforce this rule for functions // in global variable initializers once proper context is added. // // TODO: We can only enable the hostness based overloading resolution when // -fgpu-exclude-wrong-side-overloads is on since this requires deferring // overloading resolution diagnostics. if (S.getLangOpts().CUDA && Cand1.Function && Cand2.Function && S.getLangOpts().GPUExcludeWrongSideOverloads) { if (FunctionDecl *Caller = dyn_cast(S.CurContext)) { bool IsCallerImplicitHD = Sema::isCUDAImplicitHostDeviceFunction(Caller); bool IsCand1ImplicitHD = Sema::isCUDAImplicitHostDeviceFunction(Cand1.Function); bool IsCand2ImplicitHD = Sema::isCUDAImplicitHostDeviceFunction(Cand2.Function); auto P1 = S.IdentifyCUDAPreference(Caller, Cand1.Function); auto P2 = S.IdentifyCUDAPreference(Caller, Cand2.Function); assert(P1 != Sema::CFP_Never && P2 != Sema::CFP_Never); // The implicit HD function may be a function in a system header which // is forced by pragma. In device compilation, if we prefer HD candidates // over wrong-sided candidates, overloading resolution may change, which // may result in non-deferrable diagnostics. As a workaround, we let // implicit HD candidates take equal preference as wrong-sided candidates. // This will preserve the overloading resolution. // TODO: We still need special handling of implicit HD functions since // they may incur other diagnostics to be deferred. We should make all // host/device related diagnostics deferrable and remove special handling // of implicit HD functions. auto EmitThreshold = (S.getLangOpts().CUDAIsDevice && IsCallerImplicitHD && (IsCand1ImplicitHD || IsCand2ImplicitHD)) ? Sema::CFP_Never : Sema::CFP_WrongSide; auto Cand1Emittable = P1 > EmitThreshold; auto Cand2Emittable = P2 > EmitThreshold; if (Cand1Emittable && !Cand2Emittable) return true; if (!Cand1Emittable && Cand2Emittable) return false; } } // C++ [over.match.best]p1: // // -- if F is a static member function, ICS1(F) is defined such // that ICS1(F) is neither better nor worse than ICS1(G) for // any function G, and, symmetrically, ICS1(G) is neither // better nor worse than ICS1(F). unsigned StartArg = 0; if (Cand1.IgnoreObjectArgument || Cand2.IgnoreObjectArgument) StartArg = 1; auto IsIllFormedConversion = [&](const ImplicitConversionSequence &ICS) { // We don't allow incompatible pointer conversions in C++. if (!S.getLangOpts().CPlusPlus) return ICS.isStandard() && ICS.Standard.Second == ICK_Incompatible_Pointer_Conversion; // The only ill-formed conversion we allow in C++ is the string literal to // char* conversion, which is only considered ill-formed after C++11. return S.getLangOpts().CPlusPlus11 && !S.getLangOpts().WritableStrings && hasDeprecatedStringLiteralToCharPtrConversion(ICS); }; // Define functions that don't require ill-formed conversions for a given // argument to be better candidates than functions that do. unsigned NumArgs = Cand1.Conversions.size(); assert(Cand2.Conversions.size() == NumArgs && "Overload candidate mismatch"); bool HasBetterConversion = false; for (unsigned ArgIdx = StartArg; ArgIdx < NumArgs; ++ArgIdx) { bool Cand1Bad = IsIllFormedConversion(Cand1.Conversions[ArgIdx]); bool Cand2Bad = IsIllFormedConversion(Cand2.Conversions[ArgIdx]); if (Cand1Bad != Cand2Bad) { if (Cand1Bad) return false; HasBetterConversion = true; } } if (HasBetterConversion) return true; // C++ [over.match.best]p1: // A viable function F1 is defined to be a better function than another // viable function F2 if for all arguments i, ICSi(F1) is not a worse // conversion sequence than ICSi(F2), and then... bool HasWorseConversion = false; for (unsigned ArgIdx = StartArg; ArgIdx < NumArgs; ++ArgIdx) { switch (CompareImplicitConversionSequences(S, Loc, Cand1.Conversions[ArgIdx], Cand2.Conversions[ArgIdx])) { case ImplicitConversionSequence::Better: // Cand1 has a better conversion sequence. HasBetterConversion = true; break; case ImplicitConversionSequence::Worse: if (Cand1.Function && Cand2.Function && Cand1.isReversed() != Cand2.isReversed() && haveSameParameterTypes(S.Context, Cand1.Function, Cand2.Function, NumArgs)) { // Work around large-scale breakage caused by considering reversed // forms of operator== in C++20: // // When comparing a function against a reversed function with the same // parameter types, if we have a better conversion for one argument and // a worse conversion for the other, the implicit conversion sequences // are treated as being equally good. // // This prevents a comparison function from being considered ambiguous // with a reversed form that is written in the same way. // // We diagnose this as an extension from CreateOverloadedBinOp. HasWorseConversion = true; break; } // Cand1 can't be better than Cand2. return false; case ImplicitConversionSequence::Indistinguishable: // Do nothing. break; } } // -- for some argument j, ICSj(F1) is a better conversion sequence than // ICSj(F2), or, if not that, if (HasBetterConversion && !HasWorseConversion) return true; // -- the context is an initialization by user-defined conversion // (see 8.5, 13.3.1.5) and the standard conversion sequence // from the return type of F1 to the destination type (i.e., // the type of the entity being initialized) is a better // conversion sequence than the standard conversion sequence // from the return type of F2 to the destination type. if (Kind == OverloadCandidateSet::CSK_InitByUserDefinedConversion && Cand1.Function && Cand2.Function && isa(Cand1.Function) && isa(Cand2.Function)) { // First check whether we prefer one of the conversion functions over the // other. This only distinguishes the results in non-standard, extension // cases such as the conversion from a lambda closure type to a function // pointer or block. ImplicitConversionSequence::CompareKind Result = compareConversionFunctions(S, Cand1.Function, Cand2.Function); if (Result == ImplicitConversionSequence::Indistinguishable) Result = CompareStandardConversionSequences(S, Loc, Cand1.FinalConversion, Cand2.FinalConversion); if (Result != ImplicitConversionSequence::Indistinguishable) return Result == ImplicitConversionSequence::Better; // FIXME: Compare kind of reference binding if conversion functions // convert to a reference type used in direct reference binding, per // C++14 [over.match.best]p1 section 2 bullet 3. } // FIXME: Work around a defect in the C++17 guaranteed copy elision wording, // as combined with the resolution to CWG issue 243. // // When the context is initialization by constructor ([over.match.ctor] or // either phase of [over.match.list]), a constructor is preferred over // a conversion function. if (Kind == OverloadCandidateSet::CSK_InitByConstructor && NumArgs == 1 && Cand1.Function && Cand2.Function && isa(Cand1.Function) != isa(Cand2.Function)) return isa(Cand1.Function); // -- F1 is a non-template function and F2 is a function template // specialization, or, if not that, bool Cand1IsSpecialization = Cand1.Function && Cand1.Function->getPrimaryTemplate(); bool Cand2IsSpecialization = Cand2.Function && Cand2.Function->getPrimaryTemplate(); if (Cand1IsSpecialization != Cand2IsSpecialization) return Cand2IsSpecialization; // -- F1 and F2 are function template specializations, and the function // template for F1 is more specialized than the template for F2 // according to the partial ordering rules described in 14.5.5.2, or, // if not that, if (Cand1IsSpecialization && Cand2IsSpecialization) { if (FunctionTemplateDecl *BetterTemplate = S.getMoreSpecializedTemplate( Cand1.Function->getPrimaryTemplate(), Cand2.Function->getPrimaryTemplate(), Loc, isa(Cand1.Function) ? TPOC_Conversion : TPOC_Call, Cand1.ExplicitCallArguments, Cand2.ExplicitCallArguments, Cand1.isReversed() ^ Cand2.isReversed())) return BetterTemplate == Cand1.Function->getPrimaryTemplate(); } // -— F1 and F2 are non-template functions with the same // parameter-type-lists, and F1 is more constrained than F2 [...], if (Cand1.Function && Cand2.Function && !Cand1IsSpecialization && !Cand2IsSpecialization && Cand1.Function->hasPrototype() && Cand2.Function->hasPrototype()) { auto *PT1 = cast(Cand1.Function->getFunctionType()); auto *PT2 = cast(Cand2.Function->getFunctionType()); if (PT1->getNumParams() == PT2->getNumParams() && PT1->isVariadic() == PT2->isVariadic() && S.FunctionParamTypesAreEqual(PT1, PT2)) { Expr *RC1 = Cand1.Function->getTrailingRequiresClause(); Expr *RC2 = Cand2.Function->getTrailingRequiresClause(); if (RC1 && RC2) { bool AtLeastAsConstrained1, AtLeastAsConstrained2; if (S.IsAtLeastAsConstrained(Cand1.Function, {RC1}, Cand2.Function, {RC2}, AtLeastAsConstrained1) || S.IsAtLeastAsConstrained(Cand2.Function, {RC2}, Cand1.Function, {RC1}, AtLeastAsConstrained2)) return false; if (AtLeastAsConstrained1 != AtLeastAsConstrained2) return AtLeastAsConstrained1; } else if (RC1 || RC2) { return RC1 != nullptr; } } } // -- F1 is a constructor for a class D, F2 is a constructor for a base // class B of D, and for all arguments the corresponding parameters of // F1 and F2 have the same type. // FIXME: Implement the "all parameters have the same type" check. bool Cand1IsInherited = dyn_cast_or_null(Cand1.FoundDecl.getDecl()); bool Cand2IsInherited = dyn_cast_or_null(Cand2.FoundDecl.getDecl()); if (Cand1IsInherited != Cand2IsInherited) return Cand2IsInherited; else if (Cand1IsInherited) { assert(Cand2IsInherited); auto *Cand1Class = cast(Cand1.Function->getDeclContext()); auto *Cand2Class = cast(Cand2.Function->getDeclContext()); if (Cand1Class->isDerivedFrom(Cand2Class)) return true; if (Cand2Class->isDerivedFrom(Cand1Class)) return false; // Inherited from sibling base classes: still ambiguous. } // -- F2 is a rewritten candidate (12.4.1.2) and F1 is not // -- F1 and F2 are rewritten candidates, and F2 is a synthesized candidate // with reversed order of parameters and F1 is not // // We rank reversed + different operator as worse than just reversed, but // that comparison can never happen, because we only consider reversing for // the maximally-rewritten operator (== or <=>). if (Cand1.RewriteKind != Cand2.RewriteKind) return Cand1.RewriteKind < Cand2.RewriteKind; // Check C++17 tie-breakers for deduction guides. { auto *Guide1 = dyn_cast_or_null(Cand1.Function); auto *Guide2 = dyn_cast_or_null(Cand2.Function); if (Guide1 && Guide2) { // -- F1 is generated from a deduction-guide and F2 is not if (Guide1->isImplicit() != Guide2->isImplicit()) return Guide2->isImplicit(); // -- F1 is the copy deduction candidate(16.3.1.8) and F2 is not if (Guide1->isCopyDeductionCandidate()) return true; } } // Check for enable_if value-based overload resolution. if (Cand1.Function && Cand2.Function) { Comparison Cmp = compareEnableIfAttrs(S, Cand1.Function, Cand2.Function); if (Cmp != Comparison::Equal) return Cmp == Comparison::Better; } bool HasPS1 = Cand1.Function != nullptr && functionHasPassObjectSizeParams(Cand1.Function); bool HasPS2 = Cand2.Function != nullptr && functionHasPassObjectSizeParams(Cand2.Function); if (HasPS1 != HasPS2 && HasPS1) return true; auto MV = isBetterMultiversionCandidate(Cand1, Cand2); if (MV == Comparison::Better) return true; if (MV == Comparison::Worse) return false; // If other rules cannot determine which is better, CUDA preference is used // to determine which is better. if (S.getLangOpts().CUDA && Cand1.Function && Cand2.Function) { FunctionDecl *Caller = dyn_cast(S.CurContext); return S.IdentifyCUDAPreference(Caller, Cand1.Function) > S.IdentifyCUDAPreference(Caller, Cand2.Function); } return false; } /// Determine whether two declarations are "equivalent" for the purposes of /// name lookup and overload resolution. This applies when the same internal/no /// linkage entity is defined by two modules (probably by textually including /// the same header). In such a case, we don't consider the declarations to /// declare the same entity, but we also don't want lookups with both /// declarations visible to be ambiguous in some cases (this happens when using /// a modularized libstdc++). bool Sema::isEquivalentInternalLinkageDeclaration(const NamedDecl *A, const NamedDecl *B) { auto *VA = dyn_cast_or_null(A); auto *VB = dyn_cast_or_null(B); if (!VA || !VB) return false; // The declarations must be declaring the same name as an internal linkage // entity in different modules. if (!VA->getDeclContext()->getRedeclContext()->Equals( VB->getDeclContext()->getRedeclContext()) || getOwningModule(VA) == getOwningModule(VB) || VA->isExternallyVisible() || VB->isExternallyVisible()) return false; // Check that the declarations appear to be equivalent. // // FIXME: Checking the type isn't really enough to resolve the ambiguity. // For constants and functions, we should check the initializer or body is // the same. For non-constant variables, we shouldn't allow it at all. if (Context.hasSameType(VA->getType(), VB->getType())) return true; // Enum constants within unnamed enumerations will have different types, but // may still be similar enough to be interchangeable for our purposes. if (auto *EA = dyn_cast(VA)) { if (auto *EB = dyn_cast(VB)) { // Only handle anonymous enums. If the enumerations were named and // equivalent, they would have been merged to the same type. auto *EnumA = cast(EA->getDeclContext()); auto *EnumB = cast(EB->getDeclContext()); if (EnumA->hasNameForLinkage() || EnumB->hasNameForLinkage() || !Context.hasSameType(EnumA->getIntegerType(), EnumB->getIntegerType())) return false; // Allow this only if the value is the same for both enumerators. return llvm::APSInt::isSameValue(EA->getInitVal(), EB->getInitVal()); } } // Nothing else is sufficiently similar. return false; } void Sema::diagnoseEquivalentInternalLinkageDeclarations( SourceLocation Loc, const NamedDecl *D, ArrayRef Equiv) { assert(D && "Unknown declaration"); Diag(Loc, diag::ext_equivalent_internal_linkage_decl_in_modules) << D; Module *M = getOwningModule(D); Diag(D->getLocation(), diag::note_equivalent_internal_linkage_decl) << !M << (M ? M->getFullModuleName() : ""); for (auto *E : Equiv) { Module *M = getOwningModule(E); Diag(E->getLocation(), diag::note_equivalent_internal_linkage_decl) << !M << (M ? M->getFullModuleName() : ""); } } /// Computes the best viable function (C++ 13.3.3) /// within an overload candidate set. /// /// \param Loc The location of the function name (or operator symbol) for /// which overload resolution occurs. /// /// \param Best If overload resolution was successful or found a deleted /// function, \p Best points to the candidate function found. /// /// \returns The result of overload resolution. OverloadingResult OverloadCandidateSet::BestViableFunction(Sema &S, SourceLocation Loc, iterator &Best) { llvm::SmallVector Candidates; std::transform(begin(), end(), std::back_inserter(Candidates), [](OverloadCandidate &Cand) { return &Cand; }); // [CUDA] HD->H or HD->D calls are technically not allowed by CUDA but // are accepted by both clang and NVCC. However, during a particular // compilation mode only one call variant is viable. We need to // exclude non-viable overload candidates from consideration based // only on their host/device attributes. Specifically, if one // candidate call is WrongSide and the other is SameSide, we ignore // the WrongSide candidate. // We only need to remove wrong-sided candidates here if // -fgpu-exclude-wrong-side-overloads is off. When // -fgpu-exclude-wrong-side-overloads is on, all candidates are compared // uniformly in isBetterOverloadCandidate. if (S.getLangOpts().CUDA && !S.getLangOpts().GPUExcludeWrongSideOverloads) { const FunctionDecl *Caller = dyn_cast(S.CurContext); bool ContainsSameSideCandidate = llvm::any_of(Candidates, [&](OverloadCandidate *Cand) { // Check viable function only. return Cand->Viable && Cand->Function && S.IdentifyCUDAPreference(Caller, Cand->Function) == Sema::CFP_SameSide; }); if (ContainsSameSideCandidate) { auto IsWrongSideCandidate = [&](OverloadCandidate *Cand) { // Check viable function only to avoid unnecessary data copying/moving. return Cand->Viable && Cand->Function && S.IdentifyCUDAPreference(Caller, Cand->Function) == Sema::CFP_WrongSide; }; llvm::erase_if(Candidates, IsWrongSideCandidate); } } // Find the best viable function. Best = end(); for (auto *Cand : Candidates) { Cand->Best = false; if (Cand->Viable) if (Best == end() || isBetterOverloadCandidate(S, *Cand, *Best, Loc, Kind)) Best = Cand; } // If we didn't find any viable functions, abort. if (Best == end()) return OR_No_Viable_Function; llvm::SmallVector EquivalentCands; llvm::SmallVector PendingBest; PendingBest.push_back(&*Best); Best->Best = true; // Make sure that this function is better than every other viable // function. If not, we have an ambiguity. while (!PendingBest.empty()) { auto *Curr = PendingBest.pop_back_val(); for (auto *Cand : Candidates) { if (Cand->Viable && !Cand->Best && !isBetterOverloadCandidate(S, *Curr, *Cand, Loc, Kind)) { PendingBest.push_back(Cand); Cand->Best = true; if (S.isEquivalentInternalLinkageDeclaration(Cand->Function, Curr->Function)) EquivalentCands.push_back(Cand->Function); else Best = end(); } } } // If we found more than one best candidate, this is ambiguous. if (Best == end()) return OR_Ambiguous; // Best is the best viable function. if (Best->Function && Best->Function->isDeleted()) return OR_Deleted; if (!EquivalentCands.empty()) S.diagnoseEquivalentInternalLinkageDeclarations(Loc, Best->Function, EquivalentCands); return OR_Success; } namespace { enum OverloadCandidateKind { oc_function, oc_method, oc_reversed_binary_operator, oc_constructor, oc_implicit_default_constructor, oc_implicit_copy_constructor, oc_implicit_move_constructor, oc_implicit_copy_assignment, oc_implicit_move_assignment, oc_implicit_equality_comparison, oc_inherited_constructor }; enum OverloadCandidateSelect { ocs_non_template, ocs_template, ocs_described_template, }; static std::pair ClassifyOverloadCandidate(Sema &S, NamedDecl *Found, FunctionDecl *Fn, OverloadCandidateRewriteKind CRK, std::string &Description) { bool isTemplate = Fn->isTemplateDecl() || Found->isTemplateDecl(); if (FunctionTemplateDecl *FunTmpl = Fn->getPrimaryTemplate()) { isTemplate = true; Description = S.getTemplateArgumentBindingsText( FunTmpl->getTemplateParameters(), *Fn->getTemplateSpecializationArgs()); } OverloadCandidateSelect Select = [&]() { if (!Description.empty()) return ocs_described_template; return isTemplate ? ocs_template : ocs_non_template; }(); OverloadCandidateKind Kind = [&]() { if (Fn->isImplicit() && Fn->getOverloadedOperator() == OO_EqualEqual) return oc_implicit_equality_comparison; if (CRK & CRK_Reversed) return oc_reversed_binary_operator; if (CXXConstructorDecl *Ctor = dyn_cast(Fn)) { if (!Ctor->isImplicit()) { if (isa(Found)) return oc_inherited_constructor; else return oc_constructor; } if (Ctor->isDefaultConstructor()) return oc_implicit_default_constructor; if (Ctor->isMoveConstructor()) return oc_implicit_move_constructor; assert(Ctor->isCopyConstructor() && "unexpected sort of implicit constructor"); return oc_implicit_copy_constructor; } if (CXXMethodDecl *Meth = dyn_cast(Fn)) { // This actually gets spelled 'candidate function' for now, but // it doesn't hurt to split it out. if (!Meth->isImplicit()) return oc_method; if (Meth->isMoveAssignmentOperator()) return oc_implicit_move_assignment; if (Meth->isCopyAssignmentOperator()) return oc_implicit_copy_assignment; assert(isa(Meth) && "expected conversion"); return oc_method; } return oc_function; }(); return std::make_pair(Kind, Select); } void MaybeEmitInheritedConstructorNote(Sema &S, Decl *FoundDecl) { // FIXME: It'd be nice to only emit a note once per using-decl per overload // set. if (auto *Shadow = dyn_cast(FoundDecl)) S.Diag(FoundDecl->getLocation(), diag::note_ovl_candidate_inherited_constructor) << Shadow->getNominatedBaseClass(); } } // end anonymous namespace static bool isFunctionAlwaysEnabled(const ASTContext &Ctx, const FunctionDecl *FD) { for (auto *EnableIf : FD->specific_attrs()) { bool AlwaysTrue; if (EnableIf->getCond()->isValueDependent() || !EnableIf->getCond()->EvaluateAsBooleanCondition(AlwaysTrue, Ctx)) return false; if (!AlwaysTrue) return false; } return true; } /// Returns true if we can take the address of the function. /// /// \param Complain - If true, we'll emit a diagnostic /// \param InOverloadResolution - For the purposes of emitting a diagnostic, are /// we in overload resolution? /// \param Loc - The location of the statement we're complaining about. Ignored /// if we're not complaining, or if we're in overload resolution. static bool checkAddressOfFunctionIsAvailable(Sema &S, const FunctionDecl *FD, bool Complain, bool InOverloadResolution, SourceLocation Loc) { if (!isFunctionAlwaysEnabled(S.Context, FD)) { if (Complain) { if (InOverloadResolution) S.Diag(FD->getBeginLoc(), diag::note_addrof_ovl_candidate_disabled_by_enable_if_attr); else S.Diag(Loc, diag::err_addrof_function_disabled_by_enable_if_attr) << FD; } return false; } if (FD->getTrailingRequiresClause()) { ConstraintSatisfaction Satisfaction; if (S.CheckFunctionConstraints(FD, Satisfaction, Loc)) return false; if (!Satisfaction.IsSatisfied) { if (Complain) { if (InOverloadResolution) S.Diag(FD->getBeginLoc(), diag::note_ovl_candidate_unsatisfied_constraints); else S.Diag(Loc, diag::err_addrof_function_constraints_not_satisfied) << FD; S.DiagnoseUnsatisfiedConstraint(Satisfaction); } return false; } } auto I = llvm::find_if(FD->parameters(), [](const ParmVarDecl *P) { return P->hasAttr(); }); if (I == FD->param_end()) return true; if (Complain) { // Add one to ParamNo because it's user-facing unsigned ParamNo = std::distance(FD->param_begin(), I) + 1; if (InOverloadResolution) S.Diag(FD->getLocation(), diag::note_ovl_candidate_has_pass_object_size_params) << ParamNo; else S.Diag(Loc, diag::err_address_of_function_with_pass_object_size_params) << FD << ParamNo; } return false; } static bool checkAddressOfCandidateIsAvailable(Sema &S, const FunctionDecl *FD) { return checkAddressOfFunctionIsAvailable(S, FD, /*Complain=*/true, /*InOverloadResolution=*/true, /*Loc=*/SourceLocation()); } bool Sema::checkAddressOfFunctionIsAvailable(const FunctionDecl *Function, bool Complain, SourceLocation Loc) { return ::checkAddressOfFunctionIsAvailable(*this, Function, Complain, /*InOverloadResolution=*/false, Loc); } // Don't print candidates other than the one that matches the calling // convention of the call operator, since that is guaranteed to exist. static bool shouldSkipNotingLambdaConversionDecl(FunctionDecl *Fn) { const auto *ConvD = dyn_cast(Fn); if (!ConvD) return false; const auto *RD = cast(Fn->getParent()); if (!RD->isLambda()) return false; CXXMethodDecl *CallOp = RD->getLambdaCallOperator(); CallingConv CallOpCC = CallOp->getType()->castAs()->getCallConv(); QualType ConvRTy = ConvD->getType()->castAs()->getReturnType(); CallingConv ConvToCC = ConvRTy->getPointeeType()->castAs()->getCallConv(); return ConvToCC != CallOpCC; } // Notes the location of an overload candidate. void Sema::NoteOverloadCandidate(NamedDecl *Found, FunctionDecl *Fn, OverloadCandidateRewriteKind RewriteKind, QualType DestType, bool TakingAddress) { if (TakingAddress && !checkAddressOfCandidateIsAvailable(*this, Fn)) return; if (Fn->isMultiVersion() && Fn->hasAttr() && !Fn->getAttr()->isDefaultVersion()) return; if (shouldSkipNotingLambdaConversionDecl(Fn)) return; std::string FnDesc; std::pair KSPair = ClassifyOverloadCandidate(*this, Found, Fn, RewriteKind, FnDesc); PartialDiagnostic PD = PDiag(diag::note_ovl_candidate) << (unsigned)KSPair.first << (unsigned)KSPair.second << Fn << FnDesc; HandleFunctionTypeMismatch(PD, Fn->getType(), DestType); Diag(Fn->getLocation(), PD); MaybeEmitInheritedConstructorNote(*this, Found); } static void MaybeDiagnoseAmbiguousConstraints(Sema &S, ArrayRef Cands) { // Perhaps the ambiguity was caused by two atomic constraints that are // 'identical' but not equivalent: // // void foo() requires (sizeof(T) > 4) { } // #1 // void foo() requires (sizeof(T) > 4) && T::value { } // #2 // // The 'sizeof(T) > 4' constraints are seemingly equivalent and should cause // #2 to subsume #1, but these constraint are not considered equivalent // according to the subsumption rules because they are not the same // source-level construct. This behavior is quite confusing and we should try // to help the user figure out what happened. SmallVector FirstAC, SecondAC; FunctionDecl *FirstCand = nullptr, *SecondCand = nullptr; for (auto I = Cands.begin(), E = Cands.end(); I != E; ++I) { if (!I->Function) continue; SmallVector AC; if (auto *Template = I->Function->getPrimaryTemplate()) Template->getAssociatedConstraints(AC); else I->Function->getAssociatedConstraints(AC); if (AC.empty()) continue; if (FirstCand == nullptr) { FirstCand = I->Function; FirstAC = AC; } else if (SecondCand == nullptr) { SecondCand = I->Function; SecondAC = AC; } else { // We have more than one pair of constrained functions - this check is // expensive and we'd rather not try to diagnose it. return; } } if (!SecondCand) return; // The diagnostic can only happen if there are associated constraints on // both sides (there needs to be some identical atomic constraint). if (S.MaybeEmitAmbiguousAtomicConstraintsDiagnostic(FirstCand, FirstAC, SecondCand, SecondAC)) // Just show the user one diagnostic, they'll probably figure it out // from here. return; } // Notes the location of all overload candidates designated through // OverloadedExpr void Sema::NoteAllOverloadCandidates(Expr *OverloadedExpr, QualType DestType, bool TakingAddress) { assert(OverloadedExpr->getType() == Context.OverloadTy); OverloadExpr::FindResult Ovl = OverloadExpr::find(OverloadedExpr); OverloadExpr *OvlExpr = Ovl.Expression; for (UnresolvedSetIterator I = OvlExpr->decls_begin(), IEnd = OvlExpr->decls_end(); I != IEnd; ++I) { if (FunctionTemplateDecl *FunTmpl = dyn_cast((*I)->getUnderlyingDecl()) ) { NoteOverloadCandidate(*I, FunTmpl->getTemplatedDecl(), CRK_None, DestType, TakingAddress); } else if (FunctionDecl *Fun = dyn_cast((*I)->getUnderlyingDecl()) ) { NoteOverloadCandidate(*I, Fun, CRK_None, DestType, TakingAddress); } } } /// Diagnoses an ambiguous conversion. The partial diagnostic is the /// "lead" diagnostic; it will be given two arguments, the source and /// target types of the conversion. void ImplicitConversionSequence::DiagnoseAmbiguousConversion( Sema &S, SourceLocation CaretLoc, const PartialDiagnostic &PDiag) const { S.Diag(CaretLoc, PDiag) << Ambiguous.getFromType() << Ambiguous.getToType(); unsigned CandsShown = 0; AmbiguousConversionSequence::const_iterator I, E; for (I = Ambiguous.begin(), E = Ambiguous.end(); I != E; ++I) { if (CandsShown >= S.Diags.getNumOverloadCandidatesToShow()) break; ++CandsShown; S.NoteOverloadCandidate(I->first, I->second); } S.Diags.overloadCandidatesShown(CandsShown); if (I != E) S.Diag(SourceLocation(), diag::note_ovl_too_many_candidates) << int(E - I); } static void DiagnoseBadConversion(Sema &S, OverloadCandidate *Cand, unsigned I, bool TakingCandidateAddress) { const ImplicitConversionSequence &Conv = Cand->Conversions[I]; assert(Conv.isBad()); assert(Cand->Function && "for now, candidate must be a function"); FunctionDecl *Fn = Cand->Function; // There's a conversion slot for the object argument if this is a // non-constructor method. Note that 'I' corresponds the // conversion-slot index. bool isObjectArgument = false; if (isa(Fn) && !isa(Fn)) { if (I == 0) isObjectArgument = true; else I--; } std::string FnDesc; std::pair FnKindPair = ClassifyOverloadCandidate(S, Cand->FoundDecl, Fn, Cand->getRewriteKind(), FnDesc); Expr *FromExpr = Conv.Bad.FromExpr; QualType FromTy = Conv.Bad.getFromType(); QualType ToTy = Conv.Bad.getToType(); if (FromTy == S.Context.OverloadTy) { assert(FromExpr && "overload set argument came from implicit argument?"); Expr *E = FromExpr->IgnoreParens(); if (isa(E)) E = cast(E)->getSubExpr()->IgnoreParens(); DeclarationName Name = cast(E)->getName(); S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_overload) << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << ToTy << Name << I + 1; MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl); return; } // Do some hand-waving analysis to see if the non-viability is due // to a qualifier mismatch. CanQualType CFromTy = S.Context.getCanonicalType(FromTy); CanQualType CToTy = S.Context.getCanonicalType(ToTy); if (CanQual RT = CToTy->getAs()) CToTy = RT->getPointeeType(); else { // TODO: detect and diagnose the full richness of const mismatches. if (CanQual FromPT = CFromTy->getAs()) if (CanQual ToPT = CToTy->getAs()) { CFromTy = FromPT->getPointeeType(); CToTy = ToPT->getPointeeType(); } } if (CToTy.getUnqualifiedType() == CFromTy.getUnqualifiedType() && !CToTy.isAtLeastAsQualifiedAs(CFromTy)) { Qualifiers FromQs = CFromTy.getQualifiers(); Qualifiers ToQs = CToTy.getQualifiers(); if (FromQs.getAddressSpace() != ToQs.getAddressSpace()) { if (isObjectArgument) S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_addrspace_this) << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromQs.getAddressSpace() << ToQs.getAddressSpace(); else S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_addrspace) << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromQs.getAddressSpace() << ToQs.getAddressSpace() << ToTy->isReferenceType() << I + 1; MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl); return; } if (FromQs.getObjCLifetime() != ToQs.getObjCLifetime()) { S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_ownership) << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy << FromQs.getObjCLifetime() << ToQs.getObjCLifetime() << (unsigned)isObjectArgument << I + 1; MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl); return; } if (FromQs.getObjCGCAttr() != ToQs.getObjCGCAttr()) { S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_gc) << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy << FromQs.getObjCGCAttr() << ToQs.getObjCGCAttr() << (unsigned)isObjectArgument << I + 1; MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl); return; } if (FromQs.hasUnaligned() != ToQs.hasUnaligned()) { S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_unaligned) << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy << FromQs.hasUnaligned() << I + 1; MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl); return; } unsigned CVR = FromQs.getCVRQualifiers() & ~ToQs.getCVRQualifiers(); assert(CVR && "expected qualifiers mismatch"); if (isObjectArgument) { S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_cvr_this) << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy << (CVR - 1); } else { S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_cvr) << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy << (CVR - 1) << I + 1; } MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl); return; } if (Conv.Bad.Kind == BadConversionSequence::lvalue_ref_to_rvalue || Conv.Bad.Kind == BadConversionSequence::rvalue_ref_to_lvalue) { S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_value_category) << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc << (unsigned)isObjectArgument << I + 1 << (Conv.Bad.Kind == BadConversionSequence::rvalue_ref_to_lvalue) << (FromExpr ? FromExpr->getSourceRange() : SourceRange()); MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl); return; } // Special diagnostic for failure to convert an initializer list, since // telling the user that it has type void is not useful. if (FromExpr && isa(FromExpr)) { S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_list_argument) << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy << ToTy << (unsigned)isObjectArgument << I + 1; MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl); return; } // Diagnose references or pointers to incomplete types differently, // since it's far from impossible that the incompleteness triggered // the failure. QualType TempFromTy = FromTy.getNonReferenceType(); if (const PointerType *PTy = TempFromTy->getAs()) TempFromTy = PTy->getPointeeType(); if (TempFromTy->isIncompleteType()) { // Emit the generic diagnostic and, optionally, add the hints to it. S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_conv_incomplete) << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy << ToTy << (unsigned)isObjectArgument << I + 1 << (unsigned)(Cand->Fix.Kind); MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl); return; } // Diagnose base -> derived pointer conversions. unsigned BaseToDerivedConversion = 0; if (const PointerType *FromPtrTy = FromTy->getAs()) { if (const PointerType *ToPtrTy = ToTy->getAs()) { if (ToPtrTy->getPointeeType().isAtLeastAsQualifiedAs( FromPtrTy->getPointeeType()) && !FromPtrTy->getPointeeType()->isIncompleteType() && !ToPtrTy->getPointeeType()->isIncompleteType() && S.IsDerivedFrom(SourceLocation(), ToPtrTy->getPointeeType(), FromPtrTy->getPointeeType())) BaseToDerivedConversion = 1; } } else if (const ObjCObjectPointerType *FromPtrTy = FromTy->getAs()) { if (const ObjCObjectPointerType *ToPtrTy = ToTy->getAs()) if (const ObjCInterfaceDecl *FromIface = FromPtrTy->getInterfaceDecl()) if (const ObjCInterfaceDecl *ToIface = ToPtrTy->getInterfaceDecl()) if (ToPtrTy->getPointeeType().isAtLeastAsQualifiedAs( FromPtrTy->getPointeeType()) && FromIface->isSuperClassOf(ToIface)) BaseToDerivedConversion = 2; } else if (const ReferenceType *ToRefTy = ToTy->getAs()) { if (ToRefTy->getPointeeType().isAtLeastAsQualifiedAs(FromTy) && !FromTy->isIncompleteType() && !ToRefTy->getPointeeType()->isIncompleteType() && S.IsDerivedFrom(SourceLocation(), ToRefTy->getPointeeType(), FromTy)) { BaseToDerivedConversion = 3; } } if (BaseToDerivedConversion) { S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_base_to_derived_conv) << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << (BaseToDerivedConversion - 1) << FromTy << ToTy << I + 1; MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl); return; } if (isa(CFromTy) && isa(CToTy)) { Qualifiers FromQs = CFromTy.getQualifiers(); Qualifiers ToQs = CToTy.getQualifiers(); if (FromQs.getObjCLifetime() != ToQs.getObjCLifetime()) { S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_arc_conv) << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy << ToTy << (unsigned)isObjectArgument << I + 1; MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl); return; } } if (TakingCandidateAddress && !checkAddressOfCandidateIsAvailable(S, Cand->Function)) return; // Emit the generic diagnostic and, optionally, add the hints to it. PartialDiagnostic FDiag = S.PDiag(diag::note_ovl_candidate_bad_conv); FDiag << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy << ToTy << (unsigned)isObjectArgument << I + 1 << (unsigned)(Cand->Fix.Kind); // If we can fix the conversion, suggest the FixIts. for (std::vector::iterator HI = Cand->Fix.Hints.begin(), HE = Cand->Fix.Hints.end(); HI != HE; ++HI) FDiag << *HI; S.Diag(Fn->getLocation(), FDiag); MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl); } /// Additional arity mismatch diagnosis specific to a function overload /// candidates. This is not covered by the more general DiagnoseArityMismatch() /// over a candidate in any candidate set. static bool CheckArityMismatch(Sema &S, OverloadCandidate *Cand, unsigned NumArgs) { FunctionDecl *Fn = Cand->Function; unsigned MinParams = Fn->getMinRequiredArguments(); // With invalid overloaded operators, it's possible that we think we // have an arity mismatch when in fact it looks like we have the // right number of arguments, because only overloaded operators have // the weird behavior of overloading member and non-member functions. // Just don't report anything. if (Fn->isInvalidDecl() && Fn->getDeclName().getNameKind() == DeclarationName::CXXOperatorName) return true; if (NumArgs < MinParams) { assert((Cand->FailureKind == ovl_fail_too_few_arguments) || (Cand->FailureKind == ovl_fail_bad_deduction && Cand->DeductionFailure.Result == Sema::TDK_TooFewArguments)); } else { assert((Cand->FailureKind == ovl_fail_too_many_arguments) || (Cand->FailureKind == ovl_fail_bad_deduction && Cand->DeductionFailure.Result == Sema::TDK_TooManyArguments)); } return false; } /// General arity mismatch diagnosis over a candidate in a candidate set. static void DiagnoseArityMismatch(Sema &S, NamedDecl *Found, Decl *D, unsigned NumFormalArgs) { assert(isa(D) && "The templated declaration should at least be a function" " when diagnosing bad template argument deduction due to too many" " or too few arguments"); FunctionDecl *Fn = cast(D); // TODO: treat calls to a missing default constructor as a special case const auto *FnTy = Fn->getType()->castAs(); unsigned MinParams = Fn->getMinRequiredArguments(); // at least / at most / exactly unsigned mode, modeCount; if (NumFormalArgs < MinParams) { if (MinParams != FnTy->getNumParams() || FnTy->isVariadic() || FnTy->isTemplateVariadic()) mode = 0; // "at least" else mode = 2; // "exactly" modeCount = MinParams; } else { if (MinParams != FnTy->getNumParams()) mode = 1; // "at most" else mode = 2; // "exactly" modeCount = FnTy->getNumParams(); } std::string Description; std::pair FnKindPair = ClassifyOverloadCandidate(S, Found, Fn, CRK_None, Description); if (modeCount == 1 && Fn->getParamDecl(0)->getDeclName()) S.Diag(Fn->getLocation(), diag::note_ovl_candidate_arity_one) << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << Description << mode << Fn->getParamDecl(0) << NumFormalArgs; else S.Diag(Fn->getLocation(), diag::note_ovl_candidate_arity) << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << Description << mode << modeCount << NumFormalArgs; MaybeEmitInheritedConstructorNote(S, Found); } /// Arity mismatch diagnosis specific to a function overload candidate. static void DiagnoseArityMismatch(Sema &S, OverloadCandidate *Cand, unsigned NumFormalArgs) { if (!CheckArityMismatch(S, Cand, NumFormalArgs)) DiagnoseArityMismatch(S, Cand->FoundDecl, Cand->Function, NumFormalArgs); } static TemplateDecl *getDescribedTemplate(Decl *Templated) { if (TemplateDecl *TD = Templated->getDescribedTemplate()) return TD; llvm_unreachable("Unsupported: Getting the described template declaration" " for bad deduction diagnosis"); } /// Diagnose a failed template-argument deduction. static void DiagnoseBadDeduction(Sema &S, NamedDecl *Found, Decl *Templated, DeductionFailureInfo &DeductionFailure, unsigned NumArgs, bool TakingCandidateAddress) { TemplateParameter Param = DeductionFailure.getTemplateParameter(); NamedDecl *ParamD; (ParamD = Param.dyn_cast()) || (ParamD = Param.dyn_cast()) || (ParamD = Param.dyn_cast()); switch (DeductionFailure.Result) { case Sema::TDK_Success: llvm_unreachable("TDK_success while diagnosing bad deduction"); case Sema::TDK_Incomplete: { assert(ParamD && "no parameter found for incomplete deduction result"); S.Diag(Templated->getLocation(), diag::note_ovl_candidate_incomplete_deduction) << ParamD->getDeclName(); MaybeEmitInheritedConstructorNote(S, Found); return; } case Sema::TDK_IncompletePack: { assert(ParamD && "no parameter found for incomplete deduction result"); S.Diag(Templated->getLocation(), diag::note_ovl_candidate_incomplete_deduction_pack) << ParamD->getDeclName() << (DeductionFailure.getFirstArg()->pack_size() + 1) << *DeductionFailure.getFirstArg(); MaybeEmitInheritedConstructorNote(S, Found); return; } case Sema::TDK_Underqualified: { assert(ParamD && "no parameter found for bad qualifiers deduction result"); TemplateTypeParmDecl *TParam = cast(ParamD); QualType Param = DeductionFailure.getFirstArg()->getAsType(); // Param will have been canonicalized, but it should just be a // qualified version of ParamD, so move the qualifiers to that. QualifierCollector Qs; Qs.strip(Param); QualType NonCanonParam = Qs.apply(S.Context, TParam->getTypeForDecl()); assert(S.Context.hasSameType(Param, NonCanonParam)); // Arg has also been canonicalized, but there's nothing we can do // about that. It also doesn't matter as much, because it won't // have any template parameters in it (because deduction isn't // done on dependent types). QualType Arg = DeductionFailure.getSecondArg()->getAsType(); S.Diag(Templated->getLocation(), diag::note_ovl_candidate_underqualified) << ParamD->getDeclName() << Arg << NonCanonParam; MaybeEmitInheritedConstructorNote(S, Found); return; } case Sema::TDK_Inconsistent: { assert(ParamD && "no parameter found for inconsistent deduction result"); int which = 0; if (isa(ParamD)) which = 0; else if (isa(ParamD)) { // Deduction might have failed because we deduced arguments of two // different types for a non-type template parameter. // FIXME: Use a different TDK value for this. QualType T1 = DeductionFailure.getFirstArg()->getNonTypeTemplateArgumentType(); QualType T2 = DeductionFailure.getSecondArg()->getNonTypeTemplateArgumentType(); if (!T1.isNull() && !T2.isNull() && !S.Context.hasSameType(T1, T2)) { S.Diag(Templated->getLocation(), diag::note_ovl_candidate_inconsistent_deduction_types) << ParamD->getDeclName() << *DeductionFailure.getFirstArg() << T1 << *DeductionFailure.getSecondArg() << T2; MaybeEmitInheritedConstructorNote(S, Found); return; } which = 1; } else { which = 2; } // Tweak the diagnostic if the problem is that we deduced packs of // different arities. We'll print the actual packs anyway in case that // includes additional useful information. if (DeductionFailure.getFirstArg()->getKind() == TemplateArgument::Pack && DeductionFailure.getSecondArg()->getKind() == TemplateArgument::Pack && DeductionFailure.getFirstArg()->pack_size() != DeductionFailure.getSecondArg()->pack_size()) { which = 3; } S.Diag(Templated->getLocation(), diag::note_ovl_candidate_inconsistent_deduction) << which << ParamD->getDeclName() << *DeductionFailure.getFirstArg() << *DeductionFailure.getSecondArg(); MaybeEmitInheritedConstructorNote(S, Found); return; } case Sema::TDK_InvalidExplicitArguments: assert(ParamD && "no parameter found for invalid explicit arguments"); if (ParamD->getDeclName()) S.Diag(Templated->getLocation(), diag::note_ovl_candidate_explicit_arg_mismatch_named) << ParamD->getDeclName(); else { int index = 0; if (TemplateTypeParmDecl *TTP = dyn_cast(ParamD)) index = TTP->getIndex(); else if (NonTypeTemplateParmDecl *NTTP = dyn_cast(ParamD)) index = NTTP->getIndex(); else index = cast(ParamD)->getIndex(); S.Diag(Templated->getLocation(), diag::note_ovl_candidate_explicit_arg_mismatch_unnamed) << (index + 1); } MaybeEmitInheritedConstructorNote(S, Found); return; case Sema::TDK_ConstraintsNotSatisfied: { // Format the template argument list into the argument string. SmallString<128> TemplateArgString; TemplateArgumentList *Args = DeductionFailure.getTemplateArgumentList(); TemplateArgString = " "; TemplateArgString += S.getTemplateArgumentBindingsText( getDescribedTemplate(Templated)->getTemplateParameters(), *Args); if (TemplateArgString.size() == 1) TemplateArgString.clear(); S.Diag(Templated->getLocation(), diag::note_ovl_candidate_unsatisfied_constraints) << TemplateArgString; S.DiagnoseUnsatisfiedConstraint( static_cast(DeductionFailure.Data)->Satisfaction); return; } case Sema::TDK_TooManyArguments: case Sema::TDK_TooFewArguments: DiagnoseArityMismatch(S, Found, Templated, NumArgs); return; case Sema::TDK_InstantiationDepth: S.Diag(Templated->getLocation(), diag::note_ovl_candidate_instantiation_depth); MaybeEmitInheritedConstructorNote(S, Found); return; case Sema::TDK_SubstitutionFailure: { // Format the template argument list into the argument string. SmallString<128> TemplateArgString; if (TemplateArgumentList *Args = DeductionFailure.getTemplateArgumentList()) { TemplateArgString = " "; TemplateArgString += S.getTemplateArgumentBindingsText( getDescribedTemplate(Templated)->getTemplateParameters(), *Args); if (TemplateArgString.size() == 1) TemplateArgString.clear(); } // If this candidate was disabled by enable_if, say so. PartialDiagnosticAt *PDiag = DeductionFailure.getSFINAEDiagnostic(); if (PDiag && PDiag->second.getDiagID() == diag::err_typename_nested_not_found_enable_if) { // FIXME: Use the source range of the condition, and the fully-qualified // name of the enable_if template. These are both present in PDiag. S.Diag(PDiag->first, diag::note_ovl_candidate_disabled_by_enable_if) << "'enable_if'" << TemplateArgString; return; } // We found a specific requirement that disabled the enable_if. if (PDiag && PDiag->second.getDiagID() == diag::err_typename_nested_not_found_requirement) { S.Diag(Templated->getLocation(), diag::note_ovl_candidate_disabled_by_requirement) << PDiag->second.getStringArg(0) << TemplateArgString; return; } // Format the SFINAE diagnostic into the argument string. // FIXME: Add a general mechanism to include a PartialDiagnostic *'s // formatted message in another diagnostic. SmallString<128> SFINAEArgString; SourceRange R; if (PDiag) { SFINAEArgString = ": "; R = SourceRange(PDiag->first, PDiag->first); PDiag->second.EmitToString(S.getDiagnostics(), SFINAEArgString); } S.Diag(Templated->getLocation(), diag::note_ovl_candidate_substitution_failure) << TemplateArgString << SFINAEArgString << R; MaybeEmitInheritedConstructorNote(S, Found); return; } case Sema::TDK_DeducedMismatch: case Sema::TDK_DeducedMismatchNested: { // Format the template argument list into the argument string. SmallString<128> TemplateArgString; if (TemplateArgumentList *Args = DeductionFailure.getTemplateArgumentList()) { TemplateArgString = " "; TemplateArgString += S.getTemplateArgumentBindingsText( getDescribedTemplate(Templated)->getTemplateParameters(), *Args); if (TemplateArgString.size() == 1) TemplateArgString.clear(); } S.Diag(Templated->getLocation(), diag::note_ovl_candidate_deduced_mismatch) << (*DeductionFailure.getCallArgIndex() + 1) << *DeductionFailure.getFirstArg() << *DeductionFailure.getSecondArg() << TemplateArgString << (DeductionFailure.Result == Sema::TDK_DeducedMismatchNested); break; } case Sema::TDK_NonDeducedMismatch: { // FIXME: Provide a source location to indicate what we couldn't match. TemplateArgument FirstTA = *DeductionFailure.getFirstArg(); TemplateArgument SecondTA = *DeductionFailure.getSecondArg(); if (FirstTA.getKind() == TemplateArgument::Template && SecondTA.getKind() == TemplateArgument::Template) { TemplateName FirstTN = FirstTA.getAsTemplate(); TemplateName SecondTN = SecondTA.getAsTemplate(); if (FirstTN.getKind() == TemplateName::Template && SecondTN.getKind() == TemplateName::Template) { if (FirstTN.getAsTemplateDecl()->getName() == SecondTN.getAsTemplateDecl()->getName()) { // FIXME: This fixes a bad diagnostic where both templates are named // the same. This particular case is a bit difficult since: // 1) It is passed as a string to the diagnostic printer. // 2) The diagnostic printer only attempts to find a better // name for types, not decls. // Ideally, this should folded into the diagnostic printer. S.Diag(Templated->getLocation(), diag::note_ovl_candidate_non_deduced_mismatch_qualified) << FirstTN.getAsTemplateDecl() << SecondTN.getAsTemplateDecl(); return; } } } if (TakingCandidateAddress && isa(Templated) && !checkAddressOfCandidateIsAvailable(S, cast(Templated))) return; // FIXME: For generic lambda parameters, check if the function is a lambda // call operator, and if so, emit a prettier and more informative // diagnostic that mentions 'auto' and lambda in addition to // (or instead of?) the canonical template type parameters. S.Diag(Templated->getLocation(), diag::note_ovl_candidate_non_deduced_mismatch) << FirstTA << SecondTA; return; } // TODO: diagnose these individually, then kill off // note_ovl_candidate_bad_deduction, which is uselessly vague. case Sema::TDK_MiscellaneousDeductionFailure: S.Diag(Templated->getLocation(), diag::note_ovl_candidate_bad_deduction); MaybeEmitInheritedConstructorNote(S, Found); return; case Sema::TDK_CUDATargetMismatch: S.Diag(Templated->getLocation(), diag::note_cuda_ovl_candidate_target_mismatch); return; } } /// Diagnose a failed template-argument deduction, for function calls. static void DiagnoseBadDeduction(Sema &S, OverloadCandidate *Cand, unsigned NumArgs, bool TakingCandidateAddress) { unsigned TDK = Cand->DeductionFailure.Result; if (TDK == Sema::TDK_TooFewArguments || TDK == Sema::TDK_TooManyArguments) { if (CheckArityMismatch(S, Cand, NumArgs)) return; } DiagnoseBadDeduction(S, Cand->FoundDecl, Cand->Function, // pattern Cand->DeductionFailure, NumArgs, TakingCandidateAddress); } /// CUDA: diagnose an invalid call across targets. static void DiagnoseBadTarget(Sema &S, OverloadCandidate *Cand) { FunctionDecl *Caller = cast(S.CurContext); FunctionDecl *Callee = Cand->Function; Sema::CUDAFunctionTarget CallerTarget = S.IdentifyCUDATarget(Caller), CalleeTarget = S.IdentifyCUDATarget(Callee); std::string FnDesc; std::pair FnKindPair = ClassifyOverloadCandidate(S, Cand->FoundDecl, Callee, Cand->getRewriteKind(), FnDesc); S.Diag(Callee->getLocation(), diag::note_ovl_candidate_bad_target) << (unsigned)FnKindPair.first << (unsigned)ocs_non_template << FnDesc /* Ignored */ << CalleeTarget << CallerTarget; // This could be an implicit constructor for which we could not infer the // target due to a collsion. Diagnose that case. CXXMethodDecl *Meth = dyn_cast(Callee); if (Meth != nullptr && Meth->isImplicit()) { CXXRecordDecl *ParentClass = Meth->getParent(); Sema::CXXSpecialMember CSM; switch (FnKindPair.first) { default: return; case oc_implicit_default_constructor: CSM = Sema::CXXDefaultConstructor; break; case oc_implicit_copy_constructor: CSM = Sema::CXXCopyConstructor; break; case oc_implicit_move_constructor: CSM = Sema::CXXMoveConstructor; break; case oc_implicit_copy_assignment: CSM = Sema::CXXCopyAssignment; break; case oc_implicit_move_assignment: CSM = Sema::CXXMoveAssignment; break; }; bool ConstRHS = false; if (Meth->getNumParams()) { if (const ReferenceType *RT = Meth->getParamDecl(0)->getType()->getAs()) { ConstRHS = RT->getPointeeType().isConstQualified(); } } S.inferCUDATargetForImplicitSpecialMember(ParentClass, CSM, Meth, /* ConstRHS */ ConstRHS, /* Diagnose */ true); } } static void DiagnoseFailedEnableIfAttr(Sema &S, OverloadCandidate *Cand) { FunctionDecl *Callee = Cand->Function; EnableIfAttr *Attr = static_cast(Cand->DeductionFailure.Data); S.Diag(Callee->getLocation(), diag::note_ovl_candidate_disabled_by_function_cond_attr) << Attr->getCond()->getSourceRange() << Attr->getMessage(); } static void DiagnoseFailedExplicitSpec(Sema &S, OverloadCandidate *Cand) { ExplicitSpecifier ES = ExplicitSpecifier::getFromDecl(Cand->Function); assert(ES.isExplicit() && "not an explicit candidate"); unsigned Kind; switch (Cand->Function->getDeclKind()) { case Decl::Kind::CXXConstructor: Kind = 0; break; case Decl::Kind::CXXConversion: Kind = 1; break; case Decl::Kind::CXXDeductionGuide: Kind = Cand->Function->isImplicit() ? 0 : 2; break; default: llvm_unreachable("invalid Decl"); } // Note the location of the first (in-class) declaration; a redeclaration // (particularly an out-of-class definition) will typically lack the // 'explicit' specifier. // FIXME: This is probably a good thing to do for all 'candidate' notes. FunctionDecl *First = Cand->Function->getFirstDecl(); if (FunctionDecl *Pattern = First->getTemplateInstantiationPattern()) First = Pattern->getFirstDecl(); S.Diag(First->getLocation(), diag::note_ovl_candidate_explicit) << Kind << (ES.getExpr() ? 1 : 0) << (ES.getExpr() ? ES.getExpr()->getSourceRange() : SourceRange()); } /// Generates a 'note' diagnostic for an overload candidate. We've /// already generated a primary error at the call site. /// /// It really does need to be a single diagnostic with its caret /// pointed at the candidate declaration. Yes, this creates some /// major challenges of technical writing. Yes, this makes pointing /// out problems with specific arguments quite awkward. It's still /// better than generating twenty screens of text for every failed /// overload. /// /// It would be great to be able to express per-candidate problems /// more richly for those diagnostic clients that cared, but we'd /// still have to be just as careful with the default diagnostics. /// \param CtorDestAS Addr space of object being constructed (for ctor /// candidates only). static void NoteFunctionCandidate(Sema &S, OverloadCandidate *Cand, unsigned NumArgs, bool TakingCandidateAddress, LangAS CtorDestAS = LangAS::Default) { FunctionDecl *Fn = Cand->Function; if (shouldSkipNotingLambdaConversionDecl(Fn)) return; // Note deleted candidates, but only if they're viable. if (Cand->Viable) { if (Fn->isDeleted()) { std::string FnDesc; std::pair FnKindPair = ClassifyOverloadCandidate(S, Cand->FoundDecl, Fn, Cand->getRewriteKind(), FnDesc); S.Diag(Fn->getLocation(), diag::note_ovl_candidate_deleted) << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc << (Fn->isDeleted() ? (Fn->isDeletedAsWritten() ? 1 : 2) : 0); MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl); return; } // We don't really have anything else to say about viable candidates. S.NoteOverloadCandidate(Cand->FoundDecl, Fn, Cand->getRewriteKind()); return; } switch (Cand->FailureKind) { case ovl_fail_too_many_arguments: case ovl_fail_too_few_arguments: return DiagnoseArityMismatch(S, Cand, NumArgs); case ovl_fail_bad_deduction: return DiagnoseBadDeduction(S, Cand, NumArgs, TakingCandidateAddress); case ovl_fail_illegal_constructor: { S.Diag(Fn->getLocation(), diag::note_ovl_candidate_illegal_constructor) << (Fn->getPrimaryTemplate() ? 1 : 0); MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl); return; } case ovl_fail_object_addrspace_mismatch: { Qualifiers QualsForPrinting; QualsForPrinting.setAddressSpace(CtorDestAS); S.Diag(Fn->getLocation(), diag::note_ovl_candidate_illegal_constructor_adrspace_mismatch) << QualsForPrinting; MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl); return; } case ovl_fail_trivial_conversion: case ovl_fail_bad_final_conversion: case ovl_fail_final_conversion_not_exact: return S.NoteOverloadCandidate(Cand->FoundDecl, Fn, Cand->getRewriteKind()); case ovl_fail_bad_conversion: { unsigned I = (Cand->IgnoreObjectArgument ? 1 : 0); for (unsigned N = Cand->Conversions.size(); I != N; ++I) if (Cand->Conversions[I].isBad()) return DiagnoseBadConversion(S, Cand, I, TakingCandidateAddress); // FIXME: this currently happens when we're called from SemaInit // when user-conversion overload fails. Figure out how to handle // those conditions and diagnose them well. return S.NoteOverloadCandidate(Cand->FoundDecl, Fn, Cand->getRewriteKind()); } case ovl_fail_bad_target: return DiagnoseBadTarget(S, Cand); case ovl_fail_enable_if: return DiagnoseFailedEnableIfAttr(S, Cand); case ovl_fail_explicit: return DiagnoseFailedExplicitSpec(S, Cand); case ovl_fail_inhctor_slice: // It's generally not interesting to note copy/move constructors here. if (cast(Fn)->isCopyOrMoveConstructor()) return; S.Diag(Fn->getLocation(), diag::note_ovl_candidate_inherited_constructor_slice) << (Fn->getPrimaryTemplate() ? 1 : 0) << Fn->getParamDecl(0)->getType()->isRValueReferenceType(); MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl); return; case ovl_fail_addr_not_available: { bool Available = checkAddressOfCandidateIsAvailable(S, Cand->Function); (void)Available; assert(!Available); break; } case ovl_non_default_multiversion_function: // Do nothing, these should simply be ignored. break; case ovl_fail_constraints_not_satisfied: { std::string FnDesc; std::pair FnKindPair = ClassifyOverloadCandidate(S, Cand->FoundDecl, Fn, Cand->getRewriteKind(), FnDesc); S.Diag(Fn->getLocation(), diag::note_ovl_candidate_constraints_not_satisfied) << (unsigned)FnKindPair.first << (unsigned)ocs_non_template << FnDesc /* Ignored */; ConstraintSatisfaction Satisfaction; if (S.CheckFunctionConstraints(Fn, Satisfaction)) break; S.DiagnoseUnsatisfiedConstraint(Satisfaction); } } } static void NoteSurrogateCandidate(Sema &S, OverloadCandidate *Cand) { if (shouldSkipNotingLambdaConversionDecl(Cand->Surrogate)) return; // Desugar the type of the surrogate down to a function type, // retaining as many typedefs as possible while still showing // the function type (and, therefore, its parameter types). QualType FnType = Cand->Surrogate->getConversionType(); bool isLValueReference = false; bool isRValueReference = false; bool isPointer = false; if (const LValueReferenceType *FnTypeRef = FnType->getAs()) { FnType = FnTypeRef->getPointeeType(); isLValueReference = true; } else if (const RValueReferenceType *FnTypeRef = FnType->getAs()) { FnType = FnTypeRef->getPointeeType(); isRValueReference = true; } if (const PointerType *FnTypePtr = FnType->getAs()) { FnType = FnTypePtr->getPointeeType(); isPointer = true; } // Desugar down to a function type. FnType = QualType(FnType->getAs(), 0); // Reconstruct the pointer/reference as appropriate. if (isPointer) FnType = S.Context.getPointerType(FnType); if (isRValueReference) FnType = S.Context.getRValueReferenceType(FnType); if (isLValueReference) FnType = S.Context.getLValueReferenceType(FnType); S.Diag(Cand->Surrogate->getLocation(), diag::note_ovl_surrogate_cand) << FnType; } static void NoteBuiltinOperatorCandidate(Sema &S, StringRef Opc, SourceLocation OpLoc, OverloadCandidate *Cand) { assert(Cand->Conversions.size() <= 2 && "builtin operator is not binary"); std::string TypeStr("operator"); TypeStr += Opc; TypeStr += "("; TypeStr += Cand->BuiltinParamTypes[0].getAsString(); if (Cand->Conversions.size() == 1) { TypeStr += ")"; S.Diag(OpLoc, diag::note_ovl_builtin_candidate) << TypeStr; } else { TypeStr += ", "; TypeStr += Cand->BuiltinParamTypes[1].getAsString(); TypeStr += ")"; S.Diag(OpLoc, diag::note_ovl_builtin_candidate) << TypeStr; } } static void NoteAmbiguousUserConversions(Sema &S, SourceLocation OpLoc, OverloadCandidate *Cand) { for (const ImplicitConversionSequence &ICS : Cand->Conversions) { if (ICS.isBad()) break; // all meaningless after first invalid if (!ICS.isAmbiguous()) continue; ICS.DiagnoseAmbiguousConversion( S, OpLoc, S.PDiag(diag::note_ambiguous_type_conversion)); } } static SourceLocation GetLocationForCandidate(const OverloadCandidate *Cand) { if (Cand->Function) return Cand->Function->getLocation(); if (Cand->IsSurrogate) return Cand->Surrogate->getLocation(); return SourceLocation(); } static unsigned RankDeductionFailure(const DeductionFailureInfo &DFI) { switch ((Sema::TemplateDeductionResult)DFI.Result) { case Sema::TDK_Success: case Sema::TDK_NonDependentConversionFailure: llvm_unreachable("non-deduction failure while diagnosing bad deduction"); case Sema::TDK_Invalid: case Sema::TDK_Incomplete: case Sema::TDK_IncompletePack: return 1; case Sema::TDK_Underqualified: case Sema::TDK_Inconsistent: return 2; case Sema::TDK_SubstitutionFailure: case Sema::TDK_DeducedMismatch: case Sema::TDK_ConstraintsNotSatisfied: case Sema::TDK_DeducedMismatchNested: case Sema::TDK_NonDeducedMismatch: case Sema::TDK_MiscellaneousDeductionFailure: case Sema::TDK_CUDATargetMismatch: return 3; case Sema::TDK_InstantiationDepth: return 4; case Sema::TDK_InvalidExplicitArguments: return 5; case Sema::TDK_TooManyArguments: case Sema::TDK_TooFewArguments: return 6; } llvm_unreachable("Unhandled deduction result"); } namespace { struct CompareOverloadCandidatesForDisplay { Sema &S; SourceLocation Loc; size_t NumArgs; OverloadCandidateSet::CandidateSetKind CSK; CompareOverloadCandidatesForDisplay( Sema &S, SourceLocation Loc, size_t NArgs, OverloadCandidateSet::CandidateSetKind CSK) : S(S), NumArgs(NArgs), CSK(CSK) {} OverloadFailureKind EffectiveFailureKind(const OverloadCandidate *C) const { // If there are too many or too few arguments, that's the high-order bit we // want to sort by, even if the immediate failure kind was something else. if (C->FailureKind == ovl_fail_too_many_arguments || C->FailureKind == ovl_fail_too_few_arguments) return static_cast(C->FailureKind); if (C->Function) { if (NumArgs > C->Function->getNumParams() && !C->Function->isVariadic()) return ovl_fail_too_many_arguments; if (NumArgs < C->Function->getMinRequiredArguments()) return ovl_fail_too_few_arguments; } return static_cast(C->FailureKind); } bool operator()(const OverloadCandidate *L, const OverloadCandidate *R) { // Fast-path this check. if (L == R) return false; // Order first by viability. if (L->Viable) { if (!R->Viable) return true; // TODO: introduce a tri-valued comparison for overload // candidates. Would be more worthwhile if we had a sort // that could exploit it. if (isBetterOverloadCandidate(S, *L, *R, SourceLocation(), CSK)) return true; if (isBetterOverloadCandidate(S, *R, *L, SourceLocation(), CSK)) return false; } else if (R->Viable) return false; assert(L->Viable == R->Viable); // Criteria by which we can sort non-viable candidates: if (!L->Viable) { OverloadFailureKind LFailureKind = EffectiveFailureKind(L); OverloadFailureKind RFailureKind = EffectiveFailureKind(R); // 1. Arity mismatches come after other candidates. if (LFailureKind == ovl_fail_too_many_arguments || LFailureKind == ovl_fail_too_few_arguments) { if (RFailureKind == ovl_fail_too_many_arguments || RFailureKind == ovl_fail_too_few_arguments) { int LDist = std::abs((int)L->getNumParams() - (int)NumArgs); int RDist = std::abs((int)R->getNumParams() - (int)NumArgs); if (LDist == RDist) { if (LFailureKind == RFailureKind) // Sort non-surrogates before surrogates. return !L->IsSurrogate && R->IsSurrogate; // Sort candidates requiring fewer parameters than there were // arguments given after candidates requiring more parameters // than there were arguments given. return LFailureKind == ovl_fail_too_many_arguments; } return LDist < RDist; } return false; } if (RFailureKind == ovl_fail_too_many_arguments || RFailureKind == ovl_fail_too_few_arguments) return true; // 2. Bad conversions come first and are ordered by the number // of bad conversions and quality of good conversions. if (LFailureKind == ovl_fail_bad_conversion) { if (RFailureKind != ovl_fail_bad_conversion) return true; // The conversion that can be fixed with a smaller number of changes, // comes first. unsigned numLFixes = L->Fix.NumConversionsFixed; unsigned numRFixes = R->Fix.NumConversionsFixed; numLFixes = (numLFixes == 0) ? UINT_MAX : numLFixes; numRFixes = (numRFixes == 0) ? UINT_MAX : numRFixes; if (numLFixes != numRFixes) { return numLFixes < numRFixes; } // If there's any ordering between the defined conversions... // FIXME: this might not be transitive. assert(L->Conversions.size() == R->Conversions.size()); int leftBetter = 0; unsigned I = (L->IgnoreObjectArgument || R->IgnoreObjectArgument); for (unsigned E = L->Conversions.size(); I != E; ++I) { switch (CompareImplicitConversionSequences(S, Loc, L->Conversions[I], R->Conversions[I])) { case ImplicitConversionSequence::Better: leftBetter++; break; case ImplicitConversionSequence::Worse: leftBetter--; break; case ImplicitConversionSequence::Indistinguishable: break; } } if (leftBetter > 0) return true; if (leftBetter < 0) return false; } else if (RFailureKind == ovl_fail_bad_conversion) return false; if (LFailureKind == ovl_fail_bad_deduction) { if (RFailureKind != ovl_fail_bad_deduction) return true; if (L->DeductionFailure.Result != R->DeductionFailure.Result) return RankDeductionFailure(L->DeductionFailure) < RankDeductionFailure(R->DeductionFailure); } else if (RFailureKind == ovl_fail_bad_deduction) return false; // TODO: others? } // Sort everything else by location. SourceLocation LLoc = GetLocationForCandidate(L); SourceLocation RLoc = GetLocationForCandidate(R); // Put candidates without locations (e.g. builtins) at the end. if (LLoc.isInvalid()) return false; if (RLoc.isInvalid()) return true; return S.SourceMgr.isBeforeInTranslationUnit(LLoc, RLoc); } }; } /// CompleteNonViableCandidate - Normally, overload resolution only /// computes up to the first bad conversion. Produces the FixIt set if /// possible. static void CompleteNonViableCandidate(Sema &S, OverloadCandidate *Cand, ArrayRef Args, OverloadCandidateSet::CandidateSetKind CSK) { assert(!Cand->Viable); // Don't do anything on failures other than bad conversion. if (Cand->FailureKind != ovl_fail_bad_conversion) return; // We only want the FixIts if all the arguments can be corrected. bool Unfixable = false; // Use a implicit copy initialization to check conversion fixes. Cand->Fix.setConversionChecker(TryCopyInitialization); // Attempt to fix the bad conversion. unsigned ConvCount = Cand->Conversions.size(); for (unsigned ConvIdx = (Cand->IgnoreObjectArgument ? 1 : 0); /**/; ++ConvIdx) { assert(ConvIdx != ConvCount && "no bad conversion in candidate"); if (Cand->Conversions[ConvIdx].isInitialized() && Cand->Conversions[ConvIdx].isBad()) { Unfixable = !Cand->TryToFixBadConversion(ConvIdx, S); break; } } // FIXME: this should probably be preserved from the overload // operation somehow. bool SuppressUserConversions = false; unsigned ConvIdx = 0; unsigned ArgIdx = 0; ArrayRef ParamTypes; bool Reversed = Cand->isReversed(); if (Cand->IsSurrogate) { QualType ConvType = Cand->Surrogate->getConversionType().getNonReferenceType(); if (const PointerType *ConvPtrType = ConvType->getAs()) ConvType = ConvPtrType->getPointeeType(); ParamTypes = ConvType->castAs()->getParamTypes(); // Conversion 0 is 'this', which doesn't have a corresponding parameter. ConvIdx = 1; } else if (Cand->Function) { ParamTypes = Cand->Function->getType()->castAs()->getParamTypes(); if (isa(Cand->Function) && !isa(Cand->Function) && !Reversed) { // Conversion 0 is 'this', which doesn't have a corresponding parameter. ConvIdx = 1; if (CSK == OverloadCandidateSet::CSK_Operator && Cand->Function->getDeclName().getCXXOverloadedOperator() != OO_Call) // Argument 0 is 'this', which doesn't have a corresponding parameter. ArgIdx = 1; } } else { // Builtin operator. assert(ConvCount <= 3); ParamTypes = Cand->BuiltinParamTypes; } // Fill in the rest of the conversions. for (unsigned ParamIdx = Reversed ? ParamTypes.size() - 1 : 0; ConvIdx != ConvCount; ++ConvIdx, ++ArgIdx, ParamIdx += (Reversed ? -1 : 1)) { assert(ArgIdx < Args.size() && "no argument for this arg conversion"); if (Cand->Conversions[ConvIdx].isInitialized()) { // We've already checked this conversion. } else if (ParamIdx < ParamTypes.size()) { if (ParamTypes[ParamIdx]->isDependentType()) Cand->Conversions[ConvIdx].setAsIdentityConversion( Args[ArgIdx]->getType()); else { Cand->Conversions[ConvIdx] = TryCopyInitialization(S, Args[ArgIdx], ParamTypes[ParamIdx], SuppressUserConversions, /*InOverloadResolution=*/true, /*AllowObjCWritebackConversion=*/ S.getLangOpts().ObjCAutoRefCount); // Store the FixIt in the candidate if it exists. if (!Unfixable && Cand->Conversions[ConvIdx].isBad()) Unfixable = !Cand->TryToFixBadConversion(ConvIdx, S); } } else Cand->Conversions[ConvIdx].setEllipsis(); } } SmallVector OverloadCandidateSet::CompleteCandidates( Sema &S, OverloadCandidateDisplayKind OCD, ArrayRef Args, SourceLocation OpLoc, llvm::function_ref Filter) { // Sort the candidates by viability and position. Sorting directly would // be prohibitive, so we make a set of pointers and sort those. SmallVector Cands; if (OCD == OCD_AllCandidates) Cands.reserve(size()); for (iterator Cand = begin(), LastCand = end(); Cand != LastCand; ++Cand) { if (!Filter(*Cand)) continue; switch (OCD) { case OCD_AllCandidates: if (!Cand->Viable) { if (!Cand->Function && !Cand->IsSurrogate) { // This a non-viable builtin candidate. We do not, in general, // want to list every possible builtin candidate. continue; } CompleteNonViableCandidate(S, Cand, Args, Kind); } break; case OCD_ViableCandidates: if (!Cand->Viable) continue; break; case OCD_AmbiguousCandidates: if (!Cand->Best) continue; break; } Cands.push_back(Cand); } llvm::stable_sort( Cands, CompareOverloadCandidatesForDisplay(S, OpLoc, Args.size(), Kind)); return Cands; } bool OverloadCandidateSet::shouldDeferDiags(Sema &S, ArrayRef Args, SourceLocation OpLoc) { bool DeferHint = false; if (S.getLangOpts().CUDA && S.getLangOpts().GPUDeferDiag) { // Defer diagnostic for CUDA/HIP if there are wrong-sided candidates or // host device candidates. auto WrongSidedCands = CompleteCandidates(S, OCD_AllCandidates, Args, OpLoc, [](auto &Cand) { return (Cand.Viable == false && Cand.FailureKind == ovl_fail_bad_target) || (Cand.Function->template hasAttr() && Cand.Function->template hasAttr()); }); DeferHint = !WrongSidedCands.empty(); } return DeferHint; } /// When overload resolution fails, prints diagnostic messages containing the /// candidates in the candidate set. void OverloadCandidateSet::NoteCandidates( PartialDiagnosticAt PD, Sema &S, OverloadCandidateDisplayKind OCD, ArrayRef Args, StringRef Opc, SourceLocation OpLoc, llvm::function_ref Filter) { auto Cands = CompleteCandidates(S, OCD, Args, OpLoc, Filter); S.Diag(PD.first, PD.second, shouldDeferDiags(S, Args, OpLoc)); NoteCandidates(S, Args, Cands, Opc, OpLoc); if (OCD == OCD_AmbiguousCandidates) MaybeDiagnoseAmbiguousConstraints(S, {begin(), end()}); } void OverloadCandidateSet::NoteCandidates(Sema &S, ArrayRef Args, ArrayRef Cands, StringRef Opc, SourceLocation OpLoc) { bool ReportedAmbiguousConversions = false; const OverloadsShown ShowOverloads = S.Diags.getShowOverloads(); unsigned CandsShown = 0; auto I = Cands.begin(), E = Cands.end(); for (; I != E; ++I) { OverloadCandidate *Cand = *I; if (CandsShown >= S.Diags.getNumOverloadCandidatesToShow() && ShowOverloads == Ovl_Best) { break; } ++CandsShown; if (Cand->Function) NoteFunctionCandidate(S, Cand, Args.size(), /*TakingCandidateAddress=*/false, DestAS); else if (Cand->IsSurrogate) NoteSurrogateCandidate(S, Cand); else { assert(Cand->Viable && "Non-viable built-in candidates are not added to Cands."); // Generally we only see ambiguities including viable builtin // operators if overload resolution got screwed up by an // ambiguous user-defined conversion. // // FIXME: It's quite possible for different conversions to see // different ambiguities, though. if (!ReportedAmbiguousConversions) { NoteAmbiguousUserConversions(S, OpLoc, Cand); ReportedAmbiguousConversions = true; } // If this is a viable builtin, print it. NoteBuiltinOperatorCandidate(S, Opc, OpLoc, Cand); } } // Inform S.Diags that we've shown an overload set with N elements. This may // inform the future value of S.Diags.getNumOverloadCandidatesToShow(). S.Diags.overloadCandidatesShown(CandsShown); if (I != E) S.Diag(OpLoc, diag::note_ovl_too_many_candidates, shouldDeferDiags(S, Args, OpLoc)) << int(E - I); } static SourceLocation GetLocationForCandidate(const TemplateSpecCandidate *Cand) { return Cand->Specialization ? Cand->Specialization->getLocation() : SourceLocation(); } namespace { struct CompareTemplateSpecCandidatesForDisplay { Sema &S; CompareTemplateSpecCandidatesForDisplay(Sema &S) : S(S) {} bool operator()(const TemplateSpecCandidate *L, const TemplateSpecCandidate *R) { // Fast-path this check. if (L == R) return false; // Assuming that both candidates are not matches... // Sort by the ranking of deduction failures. if (L->DeductionFailure.Result != R->DeductionFailure.Result) return RankDeductionFailure(L->DeductionFailure) < RankDeductionFailure(R->DeductionFailure); // Sort everything else by location. SourceLocation LLoc = GetLocationForCandidate(L); SourceLocation RLoc = GetLocationForCandidate(R); // Put candidates without locations (e.g. builtins) at the end. if (LLoc.isInvalid()) return false; if (RLoc.isInvalid()) return true; return S.SourceMgr.isBeforeInTranslationUnit(LLoc, RLoc); } }; } /// Diagnose a template argument deduction failure. /// We are treating these failures as overload failures due to bad /// deductions. void TemplateSpecCandidate::NoteDeductionFailure(Sema &S, bool ForTakingAddress) { DiagnoseBadDeduction(S, FoundDecl, Specialization, // pattern DeductionFailure, /*NumArgs=*/0, ForTakingAddress); } void TemplateSpecCandidateSet::destroyCandidates() { for (iterator i = begin(), e = end(); i != e; ++i) { i->DeductionFailure.Destroy(); } } void TemplateSpecCandidateSet::clear() { destroyCandidates(); Candidates.clear(); } /// NoteCandidates - When no template specialization match is found, prints /// diagnostic messages containing the non-matching specializations that form /// the candidate set. /// This is analoguous to OverloadCandidateSet::NoteCandidates() with /// OCD == OCD_AllCandidates and Cand->Viable == false. void TemplateSpecCandidateSet::NoteCandidates(Sema &S, SourceLocation Loc) { // Sort the candidates by position (assuming no candidate is a match). // Sorting directly would be prohibitive, so we make a set of pointers // and sort those. SmallVector Cands; Cands.reserve(size()); for (iterator Cand = begin(), LastCand = end(); Cand != LastCand; ++Cand) { if (Cand->Specialization) Cands.push_back(Cand); // Otherwise, this is a non-matching builtin candidate. We do not, // in general, want to list every possible builtin candidate. } llvm::sort(Cands, CompareTemplateSpecCandidatesForDisplay(S)); // FIXME: Perhaps rename OverloadsShown and getShowOverloads() // for generalization purposes (?). const OverloadsShown ShowOverloads = S.Diags.getShowOverloads(); SmallVectorImpl::iterator I, E; unsigned CandsShown = 0; for (I = Cands.begin(), E = Cands.end(); I != E; ++I) { TemplateSpecCandidate *Cand = *I; // Set an arbitrary limit on the number of candidates we'll spam // the user with. FIXME: This limit should depend on details of the // candidate list. if (CandsShown >= 4 && ShowOverloads == Ovl_Best) break; ++CandsShown; assert(Cand->Specialization && "Non-matching built-in candidates are not added to Cands."); Cand->NoteDeductionFailure(S, ForTakingAddress); } if (I != E) S.Diag(Loc, diag::note_ovl_too_many_candidates) << int(E - I); } // [PossiblyAFunctionType] --> [Return] // NonFunctionType --> NonFunctionType // R (A) --> R(A) // R (*)(A) --> R (A) // R (&)(A) --> R (A) // R (S::*)(A) --> R (A) QualType Sema::ExtractUnqualifiedFunctionType(QualType PossiblyAFunctionType) { QualType Ret = PossiblyAFunctionType; if (const PointerType *ToTypePtr = PossiblyAFunctionType->getAs()) Ret = ToTypePtr->getPointeeType(); else if (const ReferenceType *ToTypeRef = PossiblyAFunctionType->getAs()) Ret = ToTypeRef->getPointeeType(); else if (const MemberPointerType *MemTypePtr = PossiblyAFunctionType->getAs()) Ret = MemTypePtr->getPointeeType(); Ret = Context.getCanonicalType(Ret).getUnqualifiedType(); return Ret; } static bool completeFunctionType(Sema &S, FunctionDecl *FD, SourceLocation Loc, bool Complain = true) { if (S.getLangOpts().CPlusPlus14 && FD->getReturnType()->isUndeducedType() && S.DeduceReturnType(FD, Loc, Complain)) return true; auto *FPT = FD->getType()->castAs(); if (S.getLangOpts().CPlusPlus17 && isUnresolvedExceptionSpec(FPT->getExceptionSpecType()) && !S.ResolveExceptionSpec(Loc, FPT)) return true; return false; } namespace { // A helper class to help with address of function resolution // - allows us to avoid passing around all those ugly parameters class AddressOfFunctionResolver { Sema& S; Expr* SourceExpr; const QualType& TargetType; QualType TargetFunctionType; // Extracted function type from target type bool Complain; //DeclAccessPair& ResultFunctionAccessPair; ASTContext& Context; bool TargetTypeIsNonStaticMemberFunction; bool FoundNonTemplateFunction; bool StaticMemberFunctionFromBoundPointer; bool HasComplained; OverloadExpr::FindResult OvlExprInfo; OverloadExpr *OvlExpr; TemplateArgumentListInfo OvlExplicitTemplateArgs; SmallVector, 4> Matches; TemplateSpecCandidateSet FailedCandidates; public: AddressOfFunctionResolver(Sema &S, Expr *SourceExpr, const QualType &TargetType, bool Complain) : S(S), SourceExpr(SourceExpr), TargetType(TargetType), Complain(Complain), Context(S.getASTContext()), TargetTypeIsNonStaticMemberFunction( !!TargetType->getAs()), FoundNonTemplateFunction(false), StaticMemberFunctionFromBoundPointer(false), HasComplained(false), OvlExprInfo(OverloadExpr::find(SourceExpr)), OvlExpr(OvlExprInfo.Expression), FailedCandidates(OvlExpr->getNameLoc(), /*ForTakingAddress=*/true) { ExtractUnqualifiedFunctionTypeFromTargetType(); if (TargetFunctionType->isFunctionType()) { if (UnresolvedMemberExpr *UME = dyn_cast(OvlExpr)) if (!UME->isImplicitAccess() && !S.ResolveSingleFunctionTemplateSpecialization(UME)) StaticMemberFunctionFromBoundPointer = true; } else if (OvlExpr->hasExplicitTemplateArgs()) { DeclAccessPair dap; if (FunctionDecl *Fn = S.ResolveSingleFunctionTemplateSpecialization( OvlExpr, false, &dap)) { if (CXXMethodDecl *Method = dyn_cast(Fn)) if (!Method->isStatic()) { // If the target type is a non-function type and the function found // is a non-static member function, pretend as if that was the // target, it's the only possible type to end up with. TargetTypeIsNonStaticMemberFunction = true; // And skip adding the function if its not in the proper form. // We'll diagnose this due to an empty set of functions. if (!OvlExprInfo.HasFormOfMemberPointer) return; } Matches.push_back(std::make_pair(dap, Fn)); } return; } if (OvlExpr->hasExplicitTemplateArgs()) OvlExpr->copyTemplateArgumentsInto(OvlExplicitTemplateArgs); if (FindAllFunctionsThatMatchTargetTypeExactly()) { // C++ [over.over]p4: // If more than one function is selected, [...] if (Matches.size() > 1 && !eliminiateSuboptimalOverloadCandidates()) { if (FoundNonTemplateFunction) EliminateAllTemplateMatches(); else EliminateAllExceptMostSpecializedTemplate(); } } if (S.getLangOpts().CUDA && Matches.size() > 1) EliminateSuboptimalCudaMatches(); } bool hasComplained() const { return HasComplained; } private: bool candidateHasExactlyCorrectType(const FunctionDecl *FD) { QualType Discard; return Context.hasSameUnqualifiedType(TargetFunctionType, FD->getType()) || S.IsFunctionConversion(FD->getType(), TargetFunctionType, Discard); } /// \return true if A is considered a better overload candidate for the /// desired type than B. bool isBetterCandidate(const FunctionDecl *A, const FunctionDecl *B) { // If A doesn't have exactly the correct type, we don't want to classify it // as "better" than anything else. This way, the user is required to // disambiguate for us if there are multiple candidates and no exact match. return candidateHasExactlyCorrectType(A) && (!candidateHasExactlyCorrectType(B) || compareEnableIfAttrs(S, A, B) == Comparison::Better); } /// \return true if we were able to eliminate all but one overload candidate, /// false otherwise. bool eliminiateSuboptimalOverloadCandidates() { // Same algorithm as overload resolution -- one pass to pick the "best", // another pass to be sure that nothing is better than the best. auto Best = Matches.begin(); for (auto I = Matches.begin()+1, E = Matches.end(); I != E; ++I) if (isBetterCandidate(I->second, Best->second)) Best = I; const FunctionDecl *BestFn = Best->second; auto IsBestOrInferiorToBest = [this, BestFn]( const std::pair &Pair) { return BestFn == Pair.second || isBetterCandidate(BestFn, Pair.second); }; // Note: We explicitly leave Matches unmodified if there isn't a clear best // option, so we can potentially give the user a better error if (!llvm::all_of(Matches, IsBestOrInferiorToBest)) return false; Matches[0] = *Best; Matches.resize(1); return true; } bool isTargetTypeAFunction() const { return TargetFunctionType->isFunctionType(); } // [ToType] [Return] // R (*)(A) --> R (A), IsNonStaticMemberFunction = false // R (&)(A) --> R (A), IsNonStaticMemberFunction = false // R (S::*)(A) --> R (A), IsNonStaticMemberFunction = true void inline ExtractUnqualifiedFunctionTypeFromTargetType() { TargetFunctionType = S.ExtractUnqualifiedFunctionType(TargetType); } // return true if any matching specializations were found bool AddMatchingTemplateFunction(FunctionTemplateDecl* FunctionTemplate, const DeclAccessPair& CurAccessFunPair) { if (CXXMethodDecl *Method = dyn_cast(FunctionTemplate->getTemplatedDecl())) { // Skip non-static function templates when converting to pointer, and // static when converting to member pointer. if (Method->isStatic() == TargetTypeIsNonStaticMemberFunction) return false; } else if (TargetTypeIsNonStaticMemberFunction) return false; // C++ [over.over]p2: // If the name is a function template, template argument deduction is // done (14.8.2.2), and if the argument deduction succeeds, the // resulting template argument list is used to generate a single // function template specialization, which is added to the set of // overloaded functions considered. FunctionDecl *Specialization = nullptr; TemplateDeductionInfo Info(FailedCandidates.getLocation()); if (Sema::TemplateDeductionResult Result = S.DeduceTemplateArguments(FunctionTemplate, &OvlExplicitTemplateArgs, TargetFunctionType, Specialization, Info, /*IsAddressOfFunction*/true)) { // Make a note of the failed deduction for diagnostics. FailedCandidates.addCandidate() .set(CurAccessFunPair, FunctionTemplate->getTemplatedDecl(), MakeDeductionFailureInfo(Context, Result, Info)); return false; } // Template argument deduction ensures that we have an exact match or // compatible pointer-to-function arguments that would be adjusted by ICS. // This function template specicalization works. assert(S.isSameOrCompatibleFunctionType( Context.getCanonicalType(Specialization->getType()), Context.getCanonicalType(TargetFunctionType))); if (!S.checkAddressOfFunctionIsAvailable(Specialization)) return false; Matches.push_back(std::make_pair(CurAccessFunPair, Specialization)); return true; } bool AddMatchingNonTemplateFunction(NamedDecl* Fn, const DeclAccessPair& CurAccessFunPair) { if (CXXMethodDecl *Method = dyn_cast(Fn)) { // Skip non-static functions when converting to pointer, and static // when converting to member pointer. if (Method->isStatic() == TargetTypeIsNonStaticMemberFunction) return false; } else if (TargetTypeIsNonStaticMemberFunction) return false; if (FunctionDecl *FunDecl = dyn_cast(Fn)) { if (S.getLangOpts().CUDA) if (FunctionDecl *Caller = dyn_cast(S.CurContext)) if (!Caller->isImplicit() && !S.IsAllowedCUDACall(Caller, FunDecl)) return false; if (FunDecl->isMultiVersion()) { const auto *TA = FunDecl->getAttr(); if (TA && !TA->isDefaultVersion()) return false; } // If any candidate has a placeholder return type, trigger its deduction // now. if (completeFunctionType(S, FunDecl, SourceExpr->getBeginLoc(), Complain)) { HasComplained |= Complain; return false; } if (!S.checkAddressOfFunctionIsAvailable(FunDecl)) return false; // If we're in C, we need to support types that aren't exactly identical. if (!S.getLangOpts().CPlusPlus || candidateHasExactlyCorrectType(FunDecl)) { Matches.push_back(std::make_pair( CurAccessFunPair, cast(FunDecl->getCanonicalDecl()))); FoundNonTemplateFunction = true; return true; } } return false; } bool FindAllFunctionsThatMatchTargetTypeExactly() { bool Ret = false; // If the overload expression doesn't have the form of a pointer to // member, don't try to convert it to a pointer-to-member type. if (IsInvalidFormOfPointerToMemberFunction()) return false; for (UnresolvedSetIterator I = OvlExpr->decls_begin(), E = OvlExpr->decls_end(); I != E; ++I) { // Look through any using declarations to find the underlying function. NamedDecl *Fn = (*I)->getUnderlyingDecl(); // C++ [over.over]p3: // Non-member functions and static member functions match // targets of type "pointer-to-function" or "reference-to-function." // Nonstatic member functions match targets of // type "pointer-to-member-function." // Note that according to DR 247, the containing class does not matter. if (FunctionTemplateDecl *FunctionTemplate = dyn_cast(Fn)) { if (AddMatchingTemplateFunction(FunctionTemplate, I.getPair())) Ret = true; } // If we have explicit template arguments supplied, skip non-templates. else if (!OvlExpr->hasExplicitTemplateArgs() && AddMatchingNonTemplateFunction(Fn, I.getPair())) Ret = true; } assert(Ret || Matches.empty()); return Ret; } void EliminateAllExceptMostSpecializedTemplate() { // [...] and any given function template specialization F1 is // eliminated if the set contains a second function template // specialization whose function template is more specialized // than the function template of F1 according to the partial // ordering rules of 14.5.5.2. // The algorithm specified above is quadratic. We instead use a // two-pass algorithm (similar to the one used to identify the // best viable function in an overload set) that identifies the // best function template (if it exists). UnresolvedSet<4> MatchesCopy; // TODO: avoid! for (unsigned I = 0, E = Matches.size(); I != E; ++I) MatchesCopy.addDecl(Matches[I].second, Matches[I].first.getAccess()); // TODO: It looks like FailedCandidates does not serve much purpose // here, since the no_viable diagnostic has index 0. UnresolvedSetIterator Result = S.getMostSpecialized( MatchesCopy.begin(), MatchesCopy.end(), FailedCandidates, SourceExpr->getBeginLoc(), S.PDiag(), S.PDiag(diag::err_addr_ovl_ambiguous) << Matches[0].second->getDeclName(), S.PDiag(diag::note_ovl_candidate) << (unsigned)oc_function << (unsigned)ocs_described_template, Complain, TargetFunctionType); if (Result != MatchesCopy.end()) { // Make it the first and only element Matches[0].first = Matches[Result - MatchesCopy.begin()].first; Matches[0].second = cast(*Result); Matches.resize(1); } else HasComplained |= Complain; } void EliminateAllTemplateMatches() { // [...] any function template specializations in the set are // eliminated if the set also contains a non-template function, [...] for (unsigned I = 0, N = Matches.size(); I != N; ) { if (Matches[I].second->getPrimaryTemplate() == nullptr) ++I; else { Matches[I] = Matches[--N]; Matches.resize(N); } } } void EliminateSuboptimalCudaMatches() { S.EraseUnwantedCUDAMatches(dyn_cast(S.CurContext), Matches); } public: void ComplainNoMatchesFound() const { assert(Matches.empty()); S.Diag(OvlExpr->getBeginLoc(), diag::err_addr_ovl_no_viable) << OvlExpr->getName() << TargetFunctionType << OvlExpr->getSourceRange(); if (FailedCandidates.empty()) S.NoteAllOverloadCandidates(OvlExpr, TargetFunctionType, /*TakingAddress=*/true); else { // We have some deduction failure messages. Use them to diagnose // the function templates, and diagnose the non-template candidates // normally. for (UnresolvedSetIterator I = OvlExpr->decls_begin(), IEnd = OvlExpr->decls_end(); I != IEnd; ++I) if (FunctionDecl *Fun = dyn_cast((*I)->getUnderlyingDecl())) if (!functionHasPassObjectSizeParams(Fun)) S.NoteOverloadCandidate(*I, Fun, CRK_None, TargetFunctionType, /*TakingAddress=*/true); FailedCandidates.NoteCandidates(S, OvlExpr->getBeginLoc()); } } bool IsInvalidFormOfPointerToMemberFunction() const { return TargetTypeIsNonStaticMemberFunction && !OvlExprInfo.HasFormOfMemberPointer; } void ComplainIsInvalidFormOfPointerToMemberFunction() const { // TODO: Should we condition this on whether any functions might // have matched, or is it more appropriate to do that in callers? // TODO: a fixit wouldn't hurt. S.Diag(OvlExpr->getNameLoc(), diag::err_addr_ovl_no_qualifier) << TargetType << OvlExpr->getSourceRange(); } bool IsStaticMemberFunctionFromBoundPointer() const { return StaticMemberFunctionFromBoundPointer; } void ComplainIsStaticMemberFunctionFromBoundPointer() const { S.Diag(OvlExpr->getBeginLoc(), diag::err_invalid_form_pointer_member_function) << OvlExpr->getSourceRange(); } void ComplainOfInvalidConversion() const { S.Diag(OvlExpr->getBeginLoc(), diag::err_addr_ovl_not_func_ptrref) << OvlExpr->getName() << TargetType; } void ComplainMultipleMatchesFound() const { assert(Matches.size() > 1); S.Diag(OvlExpr->getBeginLoc(), diag::err_addr_ovl_ambiguous) << OvlExpr->getName() << OvlExpr->getSourceRange(); S.NoteAllOverloadCandidates(OvlExpr, TargetFunctionType, /*TakingAddress=*/true); } bool hadMultipleCandidates() const { return (OvlExpr->getNumDecls() > 1); } int getNumMatches() const { return Matches.size(); } FunctionDecl* getMatchingFunctionDecl() const { if (Matches.size() != 1) return nullptr; return Matches[0].second; } const DeclAccessPair* getMatchingFunctionAccessPair() const { if (Matches.size() != 1) return nullptr; return &Matches[0].first; } }; } /// ResolveAddressOfOverloadedFunction - Try to resolve the address of /// an overloaded function (C++ [over.over]), where @p From is an /// expression with overloaded function type and @p ToType is the type /// we're trying to resolve to. For example: /// /// @code /// int f(double); /// int f(int); /// /// int (*pfd)(double) = f; // selects f(double) /// @endcode /// /// This routine returns the resulting FunctionDecl if it could be /// resolved, and NULL otherwise. When @p Complain is true, this /// routine will emit diagnostics if there is an error. FunctionDecl * Sema::ResolveAddressOfOverloadedFunction(Expr *AddressOfExpr, QualType TargetType, bool Complain, DeclAccessPair &FoundResult, bool *pHadMultipleCandidates) { assert(AddressOfExpr->getType() == Context.OverloadTy); AddressOfFunctionResolver Resolver(*this, AddressOfExpr, TargetType, Complain); int NumMatches = Resolver.getNumMatches(); FunctionDecl *Fn = nullptr; bool ShouldComplain = Complain && !Resolver.hasComplained(); if (NumMatches == 0 && ShouldComplain) { if (Resolver.IsInvalidFormOfPointerToMemberFunction()) Resolver.ComplainIsInvalidFormOfPointerToMemberFunction(); else Resolver.ComplainNoMatchesFound(); } else if (NumMatches > 1 && ShouldComplain) Resolver.ComplainMultipleMatchesFound(); else if (NumMatches == 1) { Fn = Resolver.getMatchingFunctionDecl(); assert(Fn); if (auto *FPT = Fn->getType()->getAs()) ResolveExceptionSpec(AddressOfExpr->getExprLoc(), FPT); FoundResult = *Resolver.getMatchingFunctionAccessPair(); if (Complain) { if (Resolver.IsStaticMemberFunctionFromBoundPointer()) Resolver.ComplainIsStaticMemberFunctionFromBoundPointer(); else CheckAddressOfMemberAccess(AddressOfExpr, FoundResult); } } if (pHadMultipleCandidates) *pHadMultipleCandidates = Resolver.hadMultipleCandidates(); return Fn; } /// Given an expression that refers to an overloaded function, try to /// resolve that function to a single function that can have its address taken. /// This will modify `Pair` iff it returns non-null. /// /// This routine can only succeed if from all of the candidates in the overload /// set for SrcExpr that can have their addresses taken, there is one candidate /// that is more constrained than the rest. FunctionDecl * Sema::resolveAddressOfSingleOverloadCandidate(Expr *E, DeclAccessPair &Pair) { OverloadExpr::FindResult R = OverloadExpr::find(E); OverloadExpr *Ovl = R.Expression; bool IsResultAmbiguous = false; FunctionDecl *Result = nullptr; DeclAccessPair DAP; SmallVector AmbiguousDecls; auto CheckMoreConstrained = [&] (FunctionDecl *FD1, FunctionDecl *FD2) -> Optional { SmallVector AC1, AC2; FD1->getAssociatedConstraints(AC1); FD2->getAssociatedConstraints(AC2); bool AtLeastAsConstrained1, AtLeastAsConstrained2; if (IsAtLeastAsConstrained(FD1, AC1, FD2, AC2, AtLeastAsConstrained1)) return None; if (IsAtLeastAsConstrained(FD2, AC2, FD1, AC1, AtLeastAsConstrained2)) return None; if (AtLeastAsConstrained1 == AtLeastAsConstrained2) return None; return AtLeastAsConstrained1; }; // Don't use the AddressOfResolver because we're specifically looking for // cases where we have one overload candidate that lacks // enable_if/pass_object_size/... for (auto I = Ovl->decls_begin(), E = Ovl->decls_end(); I != E; ++I) { auto *FD = dyn_cast(I->getUnderlyingDecl()); if (!FD) return nullptr; if (!checkAddressOfFunctionIsAvailable(FD)) continue; // We have more than one result - see if it is more constrained than the // previous one. if (Result) { Optional MoreConstrainedThanPrevious = CheckMoreConstrained(FD, Result); if (!MoreConstrainedThanPrevious) { IsResultAmbiguous = true; AmbiguousDecls.push_back(FD); continue; } if (!*MoreConstrainedThanPrevious) continue; // FD is more constrained - replace Result with it. } IsResultAmbiguous = false; DAP = I.getPair(); Result = FD; } if (IsResultAmbiguous) return nullptr; if (Result) { SmallVector ResultAC; // We skipped over some ambiguous declarations which might be ambiguous with // the selected result. for (FunctionDecl *Skipped : AmbiguousDecls) if (!CheckMoreConstrained(Skipped, Result).hasValue()) return nullptr; Pair = DAP; } return Result; } /// Given an overloaded function, tries to turn it into a non-overloaded /// function reference using resolveAddressOfSingleOverloadCandidate. This /// will perform access checks, diagnose the use of the resultant decl, and, if /// requested, potentially perform a function-to-pointer decay. /// /// Returns false if resolveAddressOfSingleOverloadCandidate fails. /// Otherwise, returns true. This may emit diagnostics and return true. bool Sema::resolveAndFixAddressOfSingleOverloadCandidate( ExprResult &SrcExpr, bool DoFunctionPointerConverion) { Expr *E = SrcExpr.get(); assert(E->getType() == Context.OverloadTy && "SrcExpr must be an overload"); DeclAccessPair DAP; FunctionDecl *Found = resolveAddressOfSingleOverloadCandidate(E, DAP); if (!Found || Found->isCPUDispatchMultiVersion() || Found->isCPUSpecificMultiVersion()) return false; // Emitting multiple diagnostics for a function that is both inaccessible and // unavailable is consistent with our behavior elsewhere. So, always check // for both. DiagnoseUseOfDecl(Found, E->getExprLoc()); CheckAddressOfMemberAccess(E, DAP); Expr *Fixed = FixOverloadedFunctionReference(E, DAP, Found); if (DoFunctionPointerConverion && Fixed->getType()->isFunctionType()) SrcExpr = DefaultFunctionArrayConversion(Fixed, /*Diagnose=*/false); else SrcExpr = Fixed; return true; } /// Given an expression that refers to an overloaded function, try to /// resolve that overloaded function expression down to a single function. /// /// This routine can only resolve template-ids that refer to a single function /// template, where that template-id refers to a single template whose template /// arguments are either provided by the template-id or have defaults, /// as described in C++0x [temp.arg.explicit]p3. /// /// If no template-ids are found, no diagnostics are emitted and NULL is /// returned. FunctionDecl * Sema::ResolveSingleFunctionTemplateSpecialization(OverloadExpr *ovl, bool Complain, DeclAccessPair *FoundResult) { // C++ [over.over]p1: // [...] [Note: any redundant set of parentheses surrounding the // overloaded function name is ignored (5.1). ] // C++ [over.over]p1: // [...] The overloaded function name can be preceded by the & // operator. // If we didn't actually find any template-ids, we're done. if (!ovl->hasExplicitTemplateArgs()) return nullptr; TemplateArgumentListInfo ExplicitTemplateArgs; ovl->copyTemplateArgumentsInto(ExplicitTemplateArgs); TemplateSpecCandidateSet FailedCandidates(ovl->getNameLoc()); // Look through all of the overloaded functions, searching for one // whose type matches exactly. FunctionDecl *Matched = nullptr; for (UnresolvedSetIterator I = ovl->decls_begin(), E = ovl->decls_end(); I != E; ++I) { // C++0x [temp.arg.explicit]p3: // [...] In contexts where deduction is done and fails, or in contexts // where deduction is not done, if a template argument list is // specified and it, along with any default template arguments, // identifies a single function template specialization, then the // template-id is an lvalue for the function template specialization. FunctionTemplateDecl *FunctionTemplate = cast((*I)->getUnderlyingDecl()); // C++ [over.over]p2: // If the name is a function template, template argument deduction is // done (14.8.2.2), and if the argument deduction succeeds, the // resulting template argument list is used to generate a single // function template specialization, which is added to the set of // overloaded functions considered. FunctionDecl *Specialization = nullptr; TemplateDeductionInfo Info(FailedCandidates.getLocation()); if (TemplateDeductionResult Result = DeduceTemplateArguments(FunctionTemplate, &ExplicitTemplateArgs, Specialization, Info, /*IsAddressOfFunction*/true)) { // Make a note of the failed deduction for diagnostics. // TODO: Actually use the failed-deduction info? FailedCandidates.addCandidate() .set(I.getPair(), FunctionTemplate->getTemplatedDecl(), MakeDeductionFailureInfo(Context, Result, Info)); continue; } assert(Specialization && "no specialization and no error?"); // Multiple matches; we can't resolve to a single declaration. if (Matched) { if (Complain) { Diag(ovl->getExprLoc(), diag::err_addr_ovl_ambiguous) << ovl->getName(); NoteAllOverloadCandidates(ovl); } return nullptr; } Matched = Specialization; if (FoundResult) *FoundResult = I.getPair(); } if (Matched && completeFunctionType(*this, Matched, ovl->getExprLoc(), Complain)) return nullptr; return Matched; } // Resolve and fix an overloaded expression that can be resolved // because it identifies a single function template specialization. // // Last three arguments should only be supplied if Complain = true // // Return true if it was logically possible to so resolve the // expression, regardless of whether or not it succeeded. Always // returns true if 'complain' is set. bool Sema::ResolveAndFixSingleFunctionTemplateSpecialization( ExprResult &SrcExpr, bool doFunctionPointerConverion, bool complain, SourceRange OpRangeForComplaining, QualType DestTypeForComplaining, unsigned DiagIDForComplaining) { assert(SrcExpr.get()->getType() == Context.OverloadTy); OverloadExpr::FindResult ovl = OverloadExpr::find(SrcExpr.get()); DeclAccessPair found; ExprResult SingleFunctionExpression; if (FunctionDecl *fn = ResolveSingleFunctionTemplateSpecialization( ovl.Expression, /*complain*/ false, &found)) { if (DiagnoseUseOfDecl(fn, SrcExpr.get()->getBeginLoc())) { SrcExpr = ExprError(); return true; } // It is only correct to resolve to an instance method if we're // resolving a form that's permitted to be a pointer to member. // Otherwise we'll end up making a bound member expression, which // is illegal in all the contexts we resolve like this. if (!ovl.HasFormOfMemberPointer && isa(fn) && cast(fn)->isInstance()) { if (!complain) return false; Diag(ovl.Expression->getExprLoc(), diag::err_bound_member_function) << 0 << ovl.Expression->getSourceRange(); // TODO: I believe we only end up here if there's a mix of // static and non-static candidates (otherwise the expression // would have 'bound member' type, not 'overload' type). // Ideally we would note which candidate was chosen and why // the static candidates were rejected. SrcExpr = ExprError(); return true; } // Fix the expression to refer to 'fn'. SingleFunctionExpression = FixOverloadedFunctionReference(SrcExpr.get(), found, fn); // If desired, do function-to-pointer decay. if (doFunctionPointerConverion) { SingleFunctionExpression = DefaultFunctionArrayLvalueConversion(SingleFunctionExpression.get()); if (SingleFunctionExpression.isInvalid()) { SrcExpr = ExprError(); return true; } } } if (!SingleFunctionExpression.isUsable()) { if (complain) { Diag(OpRangeForComplaining.getBegin(), DiagIDForComplaining) << ovl.Expression->getName() << DestTypeForComplaining << OpRangeForComplaining << ovl.Expression->getQualifierLoc().getSourceRange(); NoteAllOverloadCandidates(SrcExpr.get()); SrcExpr = ExprError(); return true; } return false; } SrcExpr = SingleFunctionExpression; return true; } /// Add a single candidate to the overload set. static void AddOverloadedCallCandidate(Sema &S, DeclAccessPair FoundDecl, TemplateArgumentListInfo *ExplicitTemplateArgs, ArrayRef Args, OverloadCandidateSet &CandidateSet, bool PartialOverloading, bool KnownValid) { NamedDecl *Callee = FoundDecl.getDecl(); if (isa(Callee)) Callee = cast(Callee)->getTargetDecl(); if (FunctionDecl *Func = dyn_cast(Callee)) { if (ExplicitTemplateArgs) { assert(!KnownValid && "Explicit template arguments?"); return; } // Prevent ill-formed function decls to be added as overload candidates. if (!dyn_cast(Func->getType()->getAs())) return; S.AddOverloadCandidate(Func, FoundDecl, Args, CandidateSet, /*SuppressUserConversions=*/false, PartialOverloading); return; } if (FunctionTemplateDecl *FuncTemplate = dyn_cast(Callee)) { S.AddTemplateOverloadCandidate(FuncTemplate, FoundDecl, ExplicitTemplateArgs, Args, CandidateSet, /*SuppressUserConversions=*/false, PartialOverloading); return; } assert(!KnownValid && "unhandled case in overloaded call candidate"); } /// Add the overload candidates named by callee and/or found by argument /// dependent lookup to the given overload set. void Sema::AddOverloadedCallCandidates(UnresolvedLookupExpr *ULE, ArrayRef Args, OverloadCandidateSet &CandidateSet, bool PartialOverloading) { #ifndef NDEBUG // Verify that ArgumentDependentLookup is consistent with the rules // in C++0x [basic.lookup.argdep]p3: // // Let X be the lookup set produced by unqualified lookup (3.4.1) // and let Y be the lookup set produced by argument dependent // lookup (defined as follows). If X contains // // -- a declaration of a class member, or // // -- a block-scope function declaration that is not a // using-declaration, or // // -- a declaration that is neither a function or a function // template // // then Y is empty. if (ULE->requiresADL()) { for (UnresolvedLookupExpr::decls_iterator I = ULE->decls_begin(), E = ULE->decls_end(); I != E; ++I) { assert(!(*I)->getDeclContext()->isRecord()); assert(isa(*I) || !(*I)->getDeclContext()->isFunctionOrMethod()); assert((*I)->getUnderlyingDecl()->isFunctionOrFunctionTemplate()); } } #endif // It would be nice to avoid this copy. TemplateArgumentListInfo TABuffer; TemplateArgumentListInfo *ExplicitTemplateArgs = nullptr; if (ULE->hasExplicitTemplateArgs()) { ULE->copyTemplateArgumentsInto(TABuffer); ExplicitTemplateArgs = &TABuffer; } for (UnresolvedLookupExpr::decls_iterator I = ULE->decls_begin(), E = ULE->decls_end(); I != E; ++I) AddOverloadedCallCandidate(*this, I.getPair(), ExplicitTemplateArgs, Args, CandidateSet, PartialOverloading, /*KnownValid*/ true); if (ULE->requiresADL()) AddArgumentDependentLookupCandidates(ULE->getName(), ULE->getExprLoc(), Args, ExplicitTemplateArgs, CandidateSet, PartialOverloading); } /// Add the call candidates from the given set of lookup results to the given /// overload set. Non-function lookup results are ignored. void Sema::AddOverloadedCallCandidates( LookupResult &R, TemplateArgumentListInfo *ExplicitTemplateArgs, ArrayRef Args, OverloadCandidateSet &CandidateSet) { for (LookupResult::iterator I = R.begin(), E = R.end(); I != E; ++I) AddOverloadedCallCandidate(*this, I.getPair(), ExplicitTemplateArgs, Args, CandidateSet, false, /*KnownValid*/ false); } /// Determine whether a declaration with the specified name could be moved into /// a different namespace. static bool canBeDeclaredInNamespace(const DeclarationName &Name) { switch (Name.getCXXOverloadedOperator()) { case OO_New: case OO_Array_New: case OO_Delete: case OO_Array_Delete: return false; default: return true; } } /// Attempt to recover from an ill-formed use of a non-dependent name in a /// template, where the non-dependent name was declared after the template /// was defined. This is common in code written for a compilers which do not /// correctly implement two-stage name lookup. /// /// Returns true if a viable candidate was found and a diagnostic was issued. static bool DiagnoseTwoPhaseLookup( Sema &SemaRef, SourceLocation FnLoc, const CXXScopeSpec &SS, LookupResult &R, OverloadCandidateSet::CandidateSetKind CSK, TemplateArgumentListInfo *ExplicitTemplateArgs, ArrayRef Args, CXXRecordDecl **FoundInClass = nullptr) { if (!SemaRef.inTemplateInstantiation() || !SS.isEmpty()) return false; for (DeclContext *DC = SemaRef.CurContext; DC; DC = DC->getParent()) { if (DC->isTransparentContext()) continue; SemaRef.LookupQualifiedName(R, DC); if (!R.empty()) { R.suppressDiagnostics(); OverloadCandidateSet Candidates(FnLoc, CSK); SemaRef.AddOverloadedCallCandidates(R, ExplicitTemplateArgs, Args, Candidates); OverloadCandidateSet::iterator Best; OverloadingResult OR = Candidates.BestViableFunction(SemaRef, FnLoc, Best); if (auto *RD = dyn_cast(DC)) { // We either found non-function declarations or a best viable function // at class scope. A class-scope lookup result disables ADL. Don't // look past this, but let the caller know that we found something that // either is, or might be, usable in this class. if (FoundInClass) { *FoundInClass = RD; if (OR == OR_Success) { R.clear(); R.addDecl(Best->FoundDecl.getDecl(), Best->FoundDecl.getAccess()); R.resolveKind(); } } return false; } if (OR != OR_Success) { // There wasn't a unique best function or function template. return false; } // Find the namespaces where ADL would have looked, and suggest // declaring the function there instead. Sema::AssociatedNamespaceSet AssociatedNamespaces; Sema::AssociatedClassSet AssociatedClasses; SemaRef.FindAssociatedClassesAndNamespaces(FnLoc, Args, AssociatedNamespaces, AssociatedClasses); Sema::AssociatedNamespaceSet SuggestedNamespaces; if (canBeDeclaredInNamespace(R.getLookupName())) { DeclContext *Std = SemaRef.getStdNamespace(); for (Sema::AssociatedNamespaceSet::iterator it = AssociatedNamespaces.begin(), end = AssociatedNamespaces.end(); it != end; ++it) { // Never suggest declaring a function within namespace 'std'. if (Std && Std->Encloses(*it)) continue; // Never suggest declaring a function within a namespace with a // reserved name, like __gnu_cxx. NamespaceDecl *NS = dyn_cast(*it); if (NS && NS->getQualifiedNameAsString().find("__") != std::string::npos) continue; SuggestedNamespaces.insert(*it); } } SemaRef.Diag(R.getNameLoc(), diag::err_not_found_by_two_phase_lookup) << R.getLookupName(); if (SuggestedNamespaces.empty()) { SemaRef.Diag(Best->Function->getLocation(), diag::note_not_found_by_two_phase_lookup) << R.getLookupName() << 0; } else if (SuggestedNamespaces.size() == 1) { SemaRef.Diag(Best->Function->getLocation(), diag::note_not_found_by_two_phase_lookup) << R.getLookupName() << 1 << *SuggestedNamespaces.begin(); } else { // FIXME: It would be useful to list the associated namespaces here, // but the diagnostics infrastructure doesn't provide a way to produce // a localized representation of a list of items. SemaRef.Diag(Best->Function->getLocation(), diag::note_not_found_by_two_phase_lookup) << R.getLookupName() << 2; } // Try to recover by calling this function. return true; } R.clear(); } return false; } /// Attempt to recover from ill-formed use of a non-dependent operator in a /// template, where the non-dependent operator was declared after the template /// was defined. /// /// Returns true if a viable candidate was found and a diagnostic was issued. static bool DiagnoseTwoPhaseOperatorLookup(Sema &SemaRef, OverloadedOperatorKind Op, SourceLocation OpLoc, ArrayRef Args) { DeclarationName OpName = SemaRef.Context.DeclarationNames.getCXXOperatorName(Op); LookupResult R(SemaRef, OpName, OpLoc, Sema::LookupOperatorName); return DiagnoseTwoPhaseLookup(SemaRef, OpLoc, CXXScopeSpec(), R, OverloadCandidateSet::CSK_Operator, /*ExplicitTemplateArgs=*/nullptr, Args); } namespace { class BuildRecoveryCallExprRAII { Sema &SemaRef; public: BuildRecoveryCallExprRAII(Sema &S) : SemaRef(S) { assert(SemaRef.IsBuildingRecoveryCallExpr == false); SemaRef.IsBuildingRecoveryCallExpr = true; } ~BuildRecoveryCallExprRAII() { SemaRef.IsBuildingRecoveryCallExpr = false; } }; } /// Attempts to recover from a call where no functions were found. /// /// This function will do one of three things: /// * Diagnose, recover, and return a recovery expression. /// * Diagnose, fail to recover, and return ExprError(). /// * Do not diagnose, do not recover, and return ExprResult(). The caller is /// expected to diagnose as appropriate. static ExprResult BuildRecoveryCallExpr(Sema &SemaRef, Scope *S, Expr *Fn, UnresolvedLookupExpr *ULE, SourceLocation LParenLoc, MutableArrayRef Args, SourceLocation RParenLoc, bool EmptyLookup, bool AllowTypoCorrection) { // Do not try to recover if it is already building a recovery call. // This stops infinite loops for template instantiations like // // template auto foo(T t) -> decltype(foo(t)) {} // template auto foo(T t) -> decltype(foo(&t)) {} if (SemaRef.IsBuildingRecoveryCallExpr) return ExprResult(); BuildRecoveryCallExprRAII RCE(SemaRef); CXXScopeSpec SS; SS.Adopt(ULE->getQualifierLoc()); SourceLocation TemplateKWLoc = ULE->getTemplateKeywordLoc(); TemplateArgumentListInfo TABuffer; TemplateArgumentListInfo *ExplicitTemplateArgs = nullptr; if (ULE->hasExplicitTemplateArgs()) { ULE->copyTemplateArgumentsInto(TABuffer); ExplicitTemplateArgs = &TABuffer; } LookupResult R(SemaRef, ULE->getName(), ULE->getNameLoc(), Sema::LookupOrdinaryName); CXXRecordDecl *FoundInClass = nullptr; if (DiagnoseTwoPhaseLookup(SemaRef, Fn->getExprLoc(), SS, R, OverloadCandidateSet::CSK_Normal, ExplicitTemplateArgs, Args, &FoundInClass)) { // OK, diagnosed a two-phase lookup issue. } else if (EmptyLookup) { // Try to recover from an empty lookup with typo correction. R.clear(); NoTypoCorrectionCCC NoTypoValidator{}; FunctionCallFilterCCC FunctionCallValidator(SemaRef, Args.size(), ExplicitTemplateArgs != nullptr, dyn_cast(Fn)); CorrectionCandidateCallback &Validator = AllowTypoCorrection ? static_cast(FunctionCallValidator) : static_cast(NoTypoValidator); if (SemaRef.DiagnoseEmptyLookup(S, SS, R, Validator, ExplicitTemplateArgs, Args)) return ExprError(); } else if (FoundInClass && SemaRef.getLangOpts().MSVCCompat) { // We found a usable declaration of the name in a dependent base of some // enclosing class. // FIXME: We should also explain why the candidates found by name lookup // were not viable. if (SemaRef.DiagnoseDependentMemberLookup(R)) return ExprError(); } else { // We had viable candidates and couldn't recover; let the caller diagnose // this. return ExprResult(); } // If we get here, we should have issued a diagnostic and formed a recovery // lookup result. assert(!R.empty() && "lookup results empty despite recovery"); // If recovery created an ambiguity, just bail out. if (R.isAmbiguous()) { R.suppressDiagnostics(); return ExprError(); } // Build an implicit member call if appropriate. Just drop the // casts and such from the call, we don't really care. ExprResult NewFn = ExprError(); if ((*R.begin())->isCXXClassMember()) NewFn = SemaRef.BuildPossibleImplicitMemberExpr(SS, TemplateKWLoc, R, ExplicitTemplateArgs, S); else if (ExplicitTemplateArgs || TemplateKWLoc.isValid()) NewFn = SemaRef.BuildTemplateIdExpr(SS, TemplateKWLoc, R, false, ExplicitTemplateArgs); else NewFn = SemaRef.BuildDeclarationNameExpr(SS, R, false); if (NewFn.isInvalid()) return ExprError(); // This shouldn't cause an infinite loop because we're giving it // an expression with viable lookup results, which should never // end up here. return SemaRef.BuildCallExpr(/*Scope*/ nullptr, NewFn.get(), LParenLoc, MultiExprArg(Args.data(), Args.size()), RParenLoc); } /// Constructs and populates an OverloadedCandidateSet from /// the given function. /// \returns true when an the ExprResult output parameter has been set. bool Sema::buildOverloadedCallSet(Scope *S, Expr *Fn, UnresolvedLookupExpr *ULE, MultiExprArg Args, SourceLocation RParenLoc, OverloadCandidateSet *CandidateSet, ExprResult *Result) { #ifndef NDEBUG if (ULE->requiresADL()) { // To do ADL, we must have found an unqualified name. assert(!ULE->getQualifier() && "qualified name with ADL"); // We don't perform ADL for implicit declarations of builtins. // Verify that this was correctly set up. FunctionDecl *F; if (ULE->decls_begin() != ULE->decls_end() && ULE->decls_begin() + 1 == ULE->decls_end() && (F = dyn_cast(*ULE->decls_begin())) && F->getBuiltinID() && F->isImplicit()) llvm_unreachable("performing ADL for builtin"); // We don't perform ADL in C. assert(getLangOpts().CPlusPlus && "ADL enabled in C"); } #endif UnbridgedCastsSet UnbridgedCasts; if (checkArgPlaceholdersForOverload(*this, Args, UnbridgedCasts)) { *Result = ExprError(); return true; } // Add the functions denoted by the callee to the set of candidate // functions, including those from argument-dependent lookup. AddOverloadedCallCandidates(ULE, Args, *CandidateSet); if (getLangOpts().MSVCCompat && CurContext->isDependentContext() && !isSFINAEContext() && (isa(CurContext) || isa(CurContext))) { OverloadCandidateSet::iterator Best; if (CandidateSet->empty() || CandidateSet->BestViableFunction(*this, Fn->getBeginLoc(), Best) == OR_No_Viable_Function) { // In Microsoft mode, if we are inside a template class member function // then create a type dependent CallExpr. The goal is to postpone name // lookup to instantiation time to be able to search into type dependent // base classes. CallExpr *CE = CallExpr::Create(Context, Fn, Args, Context.DependentTy, VK_RValue, RParenLoc, CurFPFeatureOverrides()); CE->markDependentForPostponedNameLookup(); *Result = CE; return true; } } if (CandidateSet->empty()) return false; UnbridgedCasts.restore(); return false; } // Guess at what the return type for an unresolvable overload should be. static QualType chooseRecoveryType(OverloadCandidateSet &CS, OverloadCandidateSet::iterator *Best) { llvm::Optional Result; // Adjust Type after seeing a candidate. auto ConsiderCandidate = [&](const OverloadCandidate &Candidate) { if (!Candidate.Function) return; if (Candidate.Function->isInvalidDecl()) return; QualType T = Candidate.Function->getReturnType(); if (T.isNull()) return; if (!Result) Result = T; else if (Result != T) Result = QualType(); }; // Look for an unambiguous type from a progressively larger subset. // e.g. if types disagree, but all *viable* overloads return int, choose int. // // First, consider only the best candidate. if (Best && *Best != CS.end()) ConsiderCandidate(**Best); // Next, consider only viable candidates. if (!Result) for (const auto &C : CS) if (C.Viable) ConsiderCandidate(C); // Finally, consider all candidates. if (!Result) for (const auto &C : CS) ConsiderCandidate(C); if (!Result) return QualType(); auto Value = Result.getValue(); if (Value.isNull() || Value->isUndeducedType()) return QualType(); return Value; } /// FinishOverloadedCallExpr - given an OverloadCandidateSet, builds and returns /// the completed call expression. If overload resolution fails, emits /// diagnostics and returns ExprError() static ExprResult FinishOverloadedCallExpr(Sema &SemaRef, Scope *S, Expr *Fn, UnresolvedLookupExpr *ULE, SourceLocation LParenLoc, MultiExprArg Args, SourceLocation RParenLoc, Expr *ExecConfig, OverloadCandidateSet *CandidateSet, OverloadCandidateSet::iterator *Best, OverloadingResult OverloadResult, bool AllowTypoCorrection) { switch (OverloadResult) { case OR_Success: { FunctionDecl *FDecl = (*Best)->Function; SemaRef.CheckUnresolvedLookupAccess(ULE, (*Best)->FoundDecl); if (SemaRef.DiagnoseUseOfDecl(FDecl, ULE->getNameLoc())) return ExprError(); Fn = SemaRef.FixOverloadedFunctionReference(Fn, (*Best)->FoundDecl, FDecl); return SemaRef.BuildResolvedCallExpr(Fn, FDecl, LParenLoc, Args, RParenLoc, ExecConfig, /*IsExecConfig=*/false, (*Best)->IsADLCandidate); } case OR_No_Viable_Function: { // Try to recover by looking for viable functions which the user might // have meant to call. ExprResult Recovery = BuildRecoveryCallExpr(SemaRef, S, Fn, ULE, LParenLoc, Args, RParenLoc, CandidateSet->empty(), AllowTypoCorrection); if (Recovery.isInvalid() || Recovery.isUsable()) return Recovery; // If the user passes in a function that we can't take the address of, we // generally end up emitting really bad error messages. Here, we attempt to // emit better ones. for (const Expr *Arg : Args) { if (!Arg->getType()->isFunctionType()) continue; if (auto *DRE = dyn_cast(Arg->IgnoreParenImpCasts())) { auto *FD = dyn_cast(DRE->getDecl()); if (FD && !SemaRef.checkAddressOfFunctionIsAvailable(FD, /*Complain=*/true, Arg->getExprLoc())) return ExprError(); } } CandidateSet->NoteCandidates( PartialDiagnosticAt( Fn->getBeginLoc(), SemaRef.PDiag(diag::err_ovl_no_viable_function_in_call) << ULE->getName() << Fn->getSourceRange()), SemaRef, OCD_AllCandidates, Args); break; } case OR_Ambiguous: CandidateSet->NoteCandidates( PartialDiagnosticAt(Fn->getBeginLoc(), SemaRef.PDiag(diag::err_ovl_ambiguous_call) << ULE->getName() << Fn->getSourceRange()), SemaRef, OCD_AmbiguousCandidates, Args); break; case OR_Deleted: { CandidateSet->NoteCandidates( PartialDiagnosticAt(Fn->getBeginLoc(), SemaRef.PDiag(diag::err_ovl_deleted_call) << ULE->getName() << Fn->getSourceRange()), SemaRef, OCD_AllCandidates, Args); // We emitted an error for the unavailable/deleted function call but keep // the call in the AST. FunctionDecl *FDecl = (*Best)->Function; Fn = SemaRef.FixOverloadedFunctionReference(Fn, (*Best)->FoundDecl, FDecl); return SemaRef.BuildResolvedCallExpr(Fn, FDecl, LParenLoc, Args, RParenLoc, ExecConfig, /*IsExecConfig=*/false, (*Best)->IsADLCandidate); } } // Overload resolution failed, try to recover. SmallVector SubExprs = {Fn}; SubExprs.append(Args.begin(), Args.end()); return SemaRef.CreateRecoveryExpr(Fn->getBeginLoc(), RParenLoc, SubExprs, chooseRecoveryType(*CandidateSet, Best)); } static void markUnaddressableCandidatesUnviable(Sema &S, OverloadCandidateSet &CS) { for (auto I = CS.begin(), E = CS.end(); I != E; ++I) { if (I->Viable && !S.checkAddressOfFunctionIsAvailable(I->Function, /*Complain=*/false)) { I->Viable = false; I->FailureKind = ovl_fail_addr_not_available; } } } /// BuildOverloadedCallExpr - Given the call expression that calls Fn /// (which eventually refers to the declaration Func) and the call /// arguments Args/NumArgs, attempt to resolve the function call down /// to a specific function. If overload resolution succeeds, returns /// the call expression produced by overload resolution. /// Otherwise, emits diagnostics and returns ExprError. ExprResult Sema::BuildOverloadedCallExpr(Scope *S, Expr *Fn, UnresolvedLookupExpr *ULE, SourceLocation LParenLoc, MultiExprArg Args, SourceLocation RParenLoc, Expr *ExecConfig, bool AllowTypoCorrection, bool CalleesAddressIsTaken) { OverloadCandidateSet CandidateSet(Fn->getExprLoc(), OverloadCandidateSet::CSK_Normal); ExprResult result; if (buildOverloadedCallSet(S, Fn, ULE, Args, LParenLoc, &CandidateSet, &result)) return result; // If the user handed us something like `(&Foo)(Bar)`, we need to ensure that // functions that aren't addressible are considered unviable. if (CalleesAddressIsTaken) markUnaddressableCandidatesUnviable(*this, CandidateSet); OverloadCandidateSet::iterator Best; OverloadingResult OverloadResult = CandidateSet.BestViableFunction(*this, Fn->getBeginLoc(), Best); return FinishOverloadedCallExpr(*this, S, Fn, ULE, LParenLoc, Args, RParenLoc, ExecConfig, &CandidateSet, &Best, OverloadResult, AllowTypoCorrection); } static bool IsOverloaded(const UnresolvedSetImpl &Functions) { return Functions.size() > 1 || (Functions.size() == 1 && isa((*Functions.begin())->getUnderlyingDecl())); } ExprResult Sema::CreateUnresolvedLookupExpr(CXXRecordDecl *NamingClass, NestedNameSpecifierLoc NNSLoc, DeclarationNameInfo DNI, const UnresolvedSetImpl &Fns, bool PerformADL) { return UnresolvedLookupExpr::Create(Context, NamingClass, NNSLoc, DNI, PerformADL, IsOverloaded(Fns), Fns.begin(), Fns.end()); } /// Create a unary operation that may resolve to an overloaded /// operator. /// /// \param OpLoc The location of the operator itself (e.g., '*'). /// /// \param Opc The UnaryOperatorKind that describes this operator. /// /// \param Fns The set of non-member functions that will be /// considered by overload resolution. The caller needs to build this /// set based on the context using, e.g., /// LookupOverloadedOperatorName() and ArgumentDependentLookup(). This /// set should not contain any member functions; those will be added /// by CreateOverloadedUnaryOp(). /// /// \param Input The input argument. ExprResult Sema::CreateOverloadedUnaryOp(SourceLocation OpLoc, UnaryOperatorKind Opc, const UnresolvedSetImpl &Fns, Expr *Input, bool PerformADL) { OverloadedOperatorKind Op = UnaryOperator::getOverloadedOperator(Opc); assert(Op != OO_None && "Invalid opcode for overloaded unary operator"); DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); // TODO: provide better source location info. DeclarationNameInfo OpNameInfo(OpName, OpLoc); if (checkPlaceholderForOverload(*this, Input)) return ExprError(); Expr *Args[2] = { Input, nullptr }; unsigned NumArgs = 1; // For post-increment and post-decrement, add the implicit '0' as // the second argument, so that we know this is a post-increment or // post-decrement. if (Opc == UO_PostInc || Opc == UO_PostDec) { llvm::APSInt Zero(Context.getTypeSize(Context.IntTy), false); Args[1] = IntegerLiteral::Create(Context, Zero, Context.IntTy, SourceLocation()); NumArgs = 2; } ArrayRef ArgsArray(Args, NumArgs); if (Input->isTypeDependent()) { if (Fns.empty()) return UnaryOperator::Create(Context, Input, Opc, Context.DependentTy, VK_RValue, OK_Ordinary, OpLoc, false, CurFPFeatureOverrides()); CXXRecordDecl *NamingClass = nullptr; // lookup ignores member operators ExprResult Fn = CreateUnresolvedLookupExpr( NamingClass, NestedNameSpecifierLoc(), OpNameInfo, Fns); if (Fn.isInvalid()) return ExprError(); return CXXOperatorCallExpr::Create(Context, Op, Fn.get(), ArgsArray, Context.DependentTy, VK_RValue, OpLoc, CurFPFeatureOverrides()); } // Build an empty overload set. OverloadCandidateSet CandidateSet(OpLoc, OverloadCandidateSet::CSK_Operator); // Add the candidates from the given function set. AddNonMemberOperatorCandidates(Fns, ArgsArray, CandidateSet); // Add operator candidates that are member functions. AddMemberOperatorCandidates(Op, OpLoc, ArgsArray, CandidateSet); // Add candidates from ADL. if (PerformADL) { AddArgumentDependentLookupCandidates(OpName, OpLoc, ArgsArray, /*ExplicitTemplateArgs*/nullptr, CandidateSet); } // Add builtin operator candidates. AddBuiltinOperatorCandidates(Op, OpLoc, ArgsArray, CandidateSet); bool HadMultipleCandidates = (CandidateSet.size() > 1); // Perform overload resolution. OverloadCandidateSet::iterator Best; switch (CandidateSet.BestViableFunction(*this, OpLoc, Best)) { case OR_Success: { // We found a built-in operator or an overloaded operator. FunctionDecl *FnDecl = Best->Function; if (FnDecl) { Expr *Base = nullptr; // We matched an overloaded operator. Build a call to that // operator. // Convert the arguments. if (CXXMethodDecl *Method = dyn_cast(FnDecl)) { CheckMemberOperatorAccess(OpLoc, Args[0], nullptr, Best->FoundDecl); ExprResult InputRes = PerformObjectArgumentInitialization(Input, /*Qualifier=*/nullptr, Best->FoundDecl, Method); if (InputRes.isInvalid()) return ExprError(); Base = Input = InputRes.get(); } else { // Convert the arguments. ExprResult InputInit = PerformCopyInitialization(InitializedEntity::InitializeParameter( Context, FnDecl->getParamDecl(0)), SourceLocation(), Input); if (InputInit.isInvalid()) return ExprError(); Input = InputInit.get(); } // Build the actual expression node. ExprResult FnExpr = CreateFunctionRefExpr(*this, FnDecl, Best->FoundDecl, Base, HadMultipleCandidates, OpLoc); if (FnExpr.isInvalid()) return ExprError(); // Determine the result type. QualType ResultTy = FnDecl->getReturnType(); ExprValueKind VK = Expr::getValueKindForType(ResultTy); ResultTy = ResultTy.getNonLValueExprType(Context); Args[0] = Input; CallExpr *TheCall = CXXOperatorCallExpr::Create( Context, Op, FnExpr.get(), ArgsArray, ResultTy, VK, OpLoc, CurFPFeatureOverrides(), Best->IsADLCandidate); if (CheckCallReturnType(FnDecl->getReturnType(), OpLoc, TheCall, FnDecl)) return ExprError(); if (CheckFunctionCall(FnDecl, TheCall, FnDecl->getType()->castAs())) return ExprError(); return CheckForImmediateInvocation(MaybeBindToTemporary(TheCall), FnDecl); } else { // We matched a built-in operator. Convert the arguments, then // break out so that we will build the appropriate built-in // operator node. ExprResult InputRes = PerformImplicitConversion( Input, Best->BuiltinParamTypes[0], Best->Conversions[0], AA_Passing, CCK_ForBuiltinOverloadedOp); if (InputRes.isInvalid()) return ExprError(); Input = InputRes.get(); break; } } case OR_No_Viable_Function: // This is an erroneous use of an operator which can be overloaded by // a non-member function. Check for non-member operators which were // defined too late to be candidates. if (DiagnoseTwoPhaseOperatorLookup(*this, Op, OpLoc, ArgsArray)) // FIXME: Recover by calling the found function. return ExprError(); // No viable function; fall through to handling this as a // built-in operator, which will produce an error message for us. break; case OR_Ambiguous: CandidateSet.NoteCandidates( PartialDiagnosticAt(OpLoc, PDiag(diag::err_ovl_ambiguous_oper_unary) << UnaryOperator::getOpcodeStr(Opc) << Input->getType() << Input->getSourceRange()), *this, OCD_AmbiguousCandidates, ArgsArray, UnaryOperator::getOpcodeStr(Opc), OpLoc); return ExprError(); case OR_Deleted: CandidateSet.NoteCandidates( PartialDiagnosticAt(OpLoc, PDiag(diag::err_ovl_deleted_oper) << UnaryOperator::getOpcodeStr(Opc) << Input->getSourceRange()), *this, OCD_AllCandidates, ArgsArray, UnaryOperator::getOpcodeStr(Opc), OpLoc); return ExprError(); } // Either we found no viable overloaded operator or we matched a // built-in operator. In either case, fall through to trying to // build a built-in operation. return CreateBuiltinUnaryOp(OpLoc, Opc, Input); } /// Perform lookup for an overloaded binary operator. void Sema::LookupOverloadedBinOp(OverloadCandidateSet &CandidateSet, OverloadedOperatorKind Op, const UnresolvedSetImpl &Fns, ArrayRef Args, bool PerformADL) { SourceLocation OpLoc = CandidateSet.getLocation(); OverloadedOperatorKind ExtraOp = CandidateSet.getRewriteInfo().AllowRewrittenCandidates ? getRewrittenOverloadedOperator(Op) : OO_None; // Add the candidates from the given function set. This also adds the // rewritten candidates using these functions if necessary. AddNonMemberOperatorCandidates(Fns, Args, CandidateSet); // Add operator candidates that are member functions. AddMemberOperatorCandidates(Op, OpLoc, Args, CandidateSet); if (CandidateSet.getRewriteInfo().shouldAddReversed(Op)) AddMemberOperatorCandidates(Op, OpLoc, {Args[1], Args[0]}, CandidateSet, OverloadCandidateParamOrder::Reversed); // In C++20, also add any rewritten member candidates. if (ExtraOp) { AddMemberOperatorCandidates(ExtraOp, OpLoc, Args, CandidateSet); if (CandidateSet.getRewriteInfo().shouldAddReversed(ExtraOp)) AddMemberOperatorCandidates(ExtraOp, OpLoc, {Args[1], Args[0]}, CandidateSet, OverloadCandidateParamOrder::Reversed); } // Add candidates from ADL. Per [over.match.oper]p2, this lookup is not // performed for an assignment operator (nor for operator[] nor operator->, // which don't get here). if (Op != OO_Equal && PerformADL) { DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); AddArgumentDependentLookupCandidates(OpName, OpLoc, Args, /*ExplicitTemplateArgs*/ nullptr, CandidateSet); if (ExtraOp) { DeclarationName ExtraOpName = Context.DeclarationNames.getCXXOperatorName(ExtraOp); AddArgumentDependentLookupCandidates(ExtraOpName, OpLoc, Args, /*ExplicitTemplateArgs*/ nullptr, CandidateSet); } } // Add builtin operator candidates. // // FIXME: We don't add any rewritten candidates here. This is strictly // incorrect; a builtin candidate could be hidden by a non-viable candidate, // resulting in our selecting a rewritten builtin candidate. For example: // // enum class E { e }; // bool operator!=(E, E) requires false; // bool k = E::e != E::e; // // ... should select the rewritten builtin candidate 'operator==(E, E)'. But // it seems unreasonable to consider rewritten builtin candidates. A core // issue has been filed proposing to removed this requirement. AddBuiltinOperatorCandidates(Op, OpLoc, Args, CandidateSet); } /// Create a binary operation that may resolve to an overloaded /// operator. /// /// \param OpLoc The location of the operator itself (e.g., '+'). /// /// \param Opc The BinaryOperatorKind that describes this operator. /// /// \param Fns The set of non-member functions that will be /// considered by overload resolution. The caller needs to build this /// set based on the context using, e.g., /// LookupOverloadedOperatorName() and ArgumentDependentLookup(). This /// set should not contain any member functions; those will be added /// by CreateOverloadedBinOp(). /// /// \param LHS Left-hand argument. /// \param RHS Right-hand argument. /// \param PerformADL Whether to consider operator candidates found by ADL. /// \param AllowRewrittenCandidates Whether to consider candidates found by /// C++20 operator rewrites. /// \param DefaultedFn If we are synthesizing a defaulted operator function, /// the function in question. Such a function is never a candidate in /// our overload resolution. This also enables synthesizing a three-way /// comparison from < and == as described in C++20 [class.spaceship]p1. ExprResult Sema::CreateOverloadedBinOp(SourceLocation OpLoc, BinaryOperatorKind Opc, const UnresolvedSetImpl &Fns, Expr *LHS, Expr *RHS, bool PerformADL, bool AllowRewrittenCandidates, FunctionDecl *DefaultedFn) { Expr *Args[2] = { LHS, RHS }; LHS=RHS=nullptr; // Please use only Args instead of LHS/RHS couple if (!getLangOpts().CPlusPlus20) AllowRewrittenCandidates = false; OverloadedOperatorKind Op = BinaryOperator::getOverloadedOperator(Opc); // If either side is type-dependent, create an appropriate dependent // expression. if (Args[0]->isTypeDependent() || Args[1]->isTypeDependent()) { if (Fns.empty()) { // If there are no functions to store, just build a dependent // BinaryOperator or CompoundAssignment. if (BinaryOperator::isCompoundAssignmentOp(Opc)) return CompoundAssignOperator::Create( Context, Args[0], Args[1], Opc, Context.DependentTy, VK_LValue, OK_Ordinary, OpLoc, CurFPFeatureOverrides(), Context.DependentTy, Context.DependentTy); return BinaryOperator::Create(Context, Args[0], Args[1], Opc, Context.DependentTy, VK_RValue, OK_Ordinary, OpLoc, CurFPFeatureOverrides()); } // FIXME: save results of ADL from here? CXXRecordDecl *NamingClass = nullptr; // lookup ignores member operators // TODO: provide better source location info in DNLoc component. DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); DeclarationNameInfo OpNameInfo(OpName, OpLoc); ExprResult Fn = CreateUnresolvedLookupExpr( NamingClass, NestedNameSpecifierLoc(), OpNameInfo, Fns, PerformADL); if (Fn.isInvalid()) return ExprError(); return CXXOperatorCallExpr::Create(Context, Op, Fn.get(), Args, Context.DependentTy, VK_RValue, OpLoc, CurFPFeatureOverrides()); } // Always do placeholder-like conversions on the RHS. if (checkPlaceholderForOverload(*this, Args[1])) return ExprError(); // Do placeholder-like conversion on the LHS; note that we should // not get here with a PseudoObject LHS. assert(Args[0]->getObjectKind() != OK_ObjCProperty); if (checkPlaceholderForOverload(*this, Args[0])) return ExprError(); // If this is the assignment operator, we only perform overload resolution // if the left-hand side is a class or enumeration type. This is actually // a hack. The standard requires that we do overload resolution between the // various built-in candidates, but as DR507 points out, this can lead to // problems. So we do it this way, which pretty much follows what GCC does. // Note that we go the traditional code path for compound assignment forms. if (Opc == BO_Assign && !Args[0]->getType()->isOverloadableType()) return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]); // If this is the .* operator, which is not overloadable, just // create a built-in binary operator. if (Opc == BO_PtrMemD) return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]); // Build the overload set. OverloadCandidateSet CandidateSet( OpLoc, OverloadCandidateSet::CSK_Operator, OverloadCandidateSet::OperatorRewriteInfo(Op, AllowRewrittenCandidates)); if (DefaultedFn) CandidateSet.exclude(DefaultedFn); LookupOverloadedBinOp(CandidateSet, Op, Fns, Args, PerformADL); bool HadMultipleCandidates = (CandidateSet.size() > 1); // Perform overload resolution. OverloadCandidateSet::iterator Best; switch (CandidateSet.BestViableFunction(*this, OpLoc, Best)) { case OR_Success: { // We found a built-in operator or an overloaded operator. FunctionDecl *FnDecl = Best->Function; bool IsReversed = Best->isReversed(); if (IsReversed) std::swap(Args[0], Args[1]); if (FnDecl) { Expr *Base = nullptr; // We matched an overloaded operator. Build a call to that // operator. OverloadedOperatorKind ChosenOp = FnDecl->getDeclName().getCXXOverloadedOperator(); // C++2a [over.match.oper]p9: // If a rewritten operator== candidate is selected by overload // resolution for an operator@, its return type shall be cv bool if (Best->RewriteKind && ChosenOp == OO_EqualEqual && !FnDecl->getReturnType()->isBooleanType()) { bool IsExtension = FnDecl->getReturnType()->isIntegralOrUnscopedEnumerationType(); Diag(OpLoc, IsExtension ? diag::ext_ovl_rewrite_equalequal_not_bool : diag::err_ovl_rewrite_equalequal_not_bool) << FnDecl->getReturnType() << BinaryOperator::getOpcodeStr(Opc) << Args[0]->getSourceRange() << Args[1]->getSourceRange(); Diag(FnDecl->getLocation(), diag::note_declared_at); if (!IsExtension) return ExprError(); } if (AllowRewrittenCandidates && !IsReversed && CandidateSet.getRewriteInfo().isReversible()) { // We could have reversed this operator, but didn't. Check if some // reversed form was a viable candidate, and if so, if it had a // better conversion for either parameter. If so, this call is // formally ambiguous, and allowing it is an extension. llvm::SmallVector AmbiguousWith; for (OverloadCandidate &Cand : CandidateSet) { if (Cand.Viable && Cand.Function && Cand.isReversed() && haveSameParameterTypes(Context, Cand.Function, FnDecl, 2)) { for (unsigned ArgIdx = 0; ArgIdx < 2; ++ArgIdx) { if (CompareImplicitConversionSequences( *this, OpLoc, Cand.Conversions[ArgIdx], Best->Conversions[ArgIdx]) == ImplicitConversionSequence::Better) { AmbiguousWith.push_back(Cand.Function); break; } } } } if (!AmbiguousWith.empty()) { bool AmbiguousWithSelf = AmbiguousWith.size() == 1 && declaresSameEntity(AmbiguousWith.front(), FnDecl); Diag(OpLoc, diag::ext_ovl_ambiguous_oper_binary_reversed) << BinaryOperator::getOpcodeStr(Opc) << Args[0]->getType() << Args[1]->getType() << AmbiguousWithSelf << Args[0]->getSourceRange() << Args[1]->getSourceRange(); if (AmbiguousWithSelf) { Diag(FnDecl->getLocation(), diag::note_ovl_ambiguous_oper_binary_reversed_self); } else { Diag(FnDecl->getLocation(), diag::note_ovl_ambiguous_oper_binary_selected_candidate); for (auto *F : AmbiguousWith) Diag(F->getLocation(), diag::note_ovl_ambiguous_oper_binary_reversed_candidate); } } } // Convert the arguments. if (CXXMethodDecl *Method = dyn_cast(FnDecl)) { // Best->Access is only meaningful for class members. CheckMemberOperatorAccess(OpLoc, Args[0], Args[1], Best->FoundDecl); ExprResult Arg1 = PerformCopyInitialization( InitializedEntity::InitializeParameter(Context, FnDecl->getParamDecl(0)), SourceLocation(), Args[1]); if (Arg1.isInvalid()) return ExprError(); ExprResult Arg0 = PerformObjectArgumentInitialization(Args[0], /*Qualifier=*/nullptr, Best->FoundDecl, Method); if (Arg0.isInvalid()) return ExprError(); Base = Args[0] = Arg0.getAs(); Args[1] = RHS = Arg1.getAs(); } else { // Convert the arguments. ExprResult Arg0 = PerformCopyInitialization( InitializedEntity::InitializeParameter(Context, FnDecl->getParamDecl(0)), SourceLocation(), Args[0]); if (Arg0.isInvalid()) return ExprError(); ExprResult Arg1 = PerformCopyInitialization( InitializedEntity::InitializeParameter(Context, FnDecl->getParamDecl(1)), SourceLocation(), Args[1]); if (Arg1.isInvalid()) return ExprError(); Args[0] = LHS = Arg0.getAs(); Args[1] = RHS = Arg1.getAs(); } // Build the actual expression node. ExprResult FnExpr = CreateFunctionRefExpr(*this, FnDecl, Best->FoundDecl, Base, HadMultipleCandidates, OpLoc); if (FnExpr.isInvalid()) return ExprError(); // Determine the result type. QualType ResultTy = FnDecl->getReturnType(); ExprValueKind VK = Expr::getValueKindForType(ResultTy); ResultTy = ResultTy.getNonLValueExprType(Context); CXXOperatorCallExpr *TheCall = CXXOperatorCallExpr::Create( Context, ChosenOp, FnExpr.get(), Args, ResultTy, VK, OpLoc, CurFPFeatureOverrides(), Best->IsADLCandidate); if (CheckCallReturnType(FnDecl->getReturnType(), OpLoc, TheCall, FnDecl)) return ExprError(); ArrayRef ArgsArray(Args, 2); const Expr *ImplicitThis = nullptr; // Cut off the implicit 'this'. if (isa(FnDecl)) { ImplicitThis = ArgsArray[0]; ArgsArray = ArgsArray.slice(1); } // Check for a self move. if (Op == OO_Equal) DiagnoseSelfMove(Args[0], Args[1], OpLoc); if (ImplicitThis) { QualType ThisType = Context.getPointerType(ImplicitThis->getType()); QualType ThisTypeFromDecl = Context.getPointerType( cast(FnDecl)->getThisObjectType()); CheckArgAlignment(OpLoc, FnDecl, "'this'", ThisType, ThisTypeFromDecl); } checkCall(FnDecl, nullptr, ImplicitThis, ArgsArray, isa(FnDecl), OpLoc, TheCall->getSourceRange(), VariadicDoesNotApply); ExprResult R = MaybeBindToTemporary(TheCall); if (R.isInvalid()) return ExprError(); R = CheckForImmediateInvocation(R, FnDecl); if (R.isInvalid()) return ExprError(); // For a rewritten candidate, we've already reversed the arguments // if needed. Perform the rest of the rewrite now. if ((Best->RewriteKind & CRK_DifferentOperator) || (Op == OO_Spaceship && IsReversed)) { if (Op == OO_ExclaimEqual) { assert(ChosenOp == OO_EqualEqual && "unexpected operator name"); R = CreateBuiltinUnaryOp(OpLoc, UO_LNot, R.get()); } else { assert(ChosenOp == OO_Spaceship && "unexpected operator name"); llvm::APSInt Zero(Context.getTypeSize(Context.IntTy), false); Expr *ZeroLiteral = IntegerLiteral::Create(Context, Zero, Context.IntTy, OpLoc); Sema::CodeSynthesisContext Ctx; Ctx.Kind = Sema::CodeSynthesisContext::RewritingOperatorAsSpaceship; Ctx.Entity = FnDecl; pushCodeSynthesisContext(Ctx); R = CreateOverloadedBinOp( OpLoc, Opc, Fns, IsReversed ? ZeroLiteral : R.get(), IsReversed ? R.get() : ZeroLiteral, PerformADL, /*AllowRewrittenCandidates=*/false); popCodeSynthesisContext(); } if (R.isInvalid()) return ExprError(); } else { assert(ChosenOp == Op && "unexpected operator name"); } // Make a note in the AST if we did any rewriting. if (Best->RewriteKind != CRK_None) R = new (Context) CXXRewrittenBinaryOperator(R.get(), IsReversed); return R; } else { // We matched a built-in operator. Convert the arguments, then // break out so that we will build the appropriate built-in // operator node. ExprResult ArgsRes0 = PerformImplicitConversion( Args[0], Best->BuiltinParamTypes[0], Best->Conversions[0], AA_Passing, CCK_ForBuiltinOverloadedOp); if (ArgsRes0.isInvalid()) return ExprError(); Args[0] = ArgsRes0.get(); ExprResult ArgsRes1 = PerformImplicitConversion( Args[1], Best->BuiltinParamTypes[1], Best->Conversions[1], AA_Passing, CCK_ForBuiltinOverloadedOp); if (ArgsRes1.isInvalid()) return ExprError(); Args[1] = ArgsRes1.get(); break; } } case OR_No_Viable_Function: { // C++ [over.match.oper]p9: // If the operator is the operator , [...] and there are no // viable functions, then the operator is assumed to be the // built-in operator and interpreted according to clause 5. if (Opc == BO_Comma) break; // When defaulting an 'operator<=>', we can try to synthesize a three-way // compare result using '==' and '<'. if (DefaultedFn && Opc == BO_Cmp) { ExprResult E = BuildSynthesizedThreeWayComparison(OpLoc, Fns, Args[0], Args[1], DefaultedFn); if (E.isInvalid() || E.isUsable()) return E; } // For class as left operand for assignment or compound assignment // operator do not fall through to handling in built-in, but report that // no overloaded assignment operator found ExprResult Result = ExprError(); StringRef OpcStr = BinaryOperator::getOpcodeStr(Opc); auto Cands = CandidateSet.CompleteCandidates(*this, OCD_AllCandidates, Args, OpLoc); if (Args[0]->getType()->isRecordType() && Opc >= BO_Assign && Opc <= BO_OrAssign) { Diag(OpLoc, diag::err_ovl_no_viable_oper) << BinaryOperator::getOpcodeStr(Opc) << Args[0]->getSourceRange() << Args[1]->getSourceRange(); if (Args[0]->getType()->isIncompleteType()) { Diag(OpLoc, diag::note_assign_lhs_incomplete) << Args[0]->getType() << Args[0]->getSourceRange() << Args[1]->getSourceRange(); } } else { // This is an erroneous use of an operator which can be overloaded by // a non-member function. Check for non-member operators which were // defined too late to be candidates. if (DiagnoseTwoPhaseOperatorLookup(*this, Op, OpLoc, Args)) // FIXME: Recover by calling the found function. return ExprError(); // No viable function; try to create a built-in operation, which will // produce an error. Then, show the non-viable candidates. Result = CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]); } assert(Result.isInvalid() && "C++ binary operator overloading is missing candidates!"); CandidateSet.NoteCandidates(*this, Args, Cands, OpcStr, OpLoc); return Result; } case OR_Ambiguous: CandidateSet.NoteCandidates( PartialDiagnosticAt(OpLoc, PDiag(diag::err_ovl_ambiguous_oper_binary) << BinaryOperator::getOpcodeStr(Opc) << Args[0]->getType() << Args[1]->getType() << Args[0]->getSourceRange() << Args[1]->getSourceRange()), *this, OCD_AmbiguousCandidates, Args, BinaryOperator::getOpcodeStr(Opc), OpLoc); return ExprError(); case OR_Deleted: if (isImplicitlyDeleted(Best->Function)) { FunctionDecl *DeletedFD = Best->Function; DefaultedFunctionKind DFK = getDefaultedFunctionKind(DeletedFD); if (DFK.isSpecialMember()) { Diag(OpLoc, diag::err_ovl_deleted_special_oper) << Args[0]->getType() << DFK.asSpecialMember(); } else { assert(DFK.isComparison()); Diag(OpLoc, diag::err_ovl_deleted_comparison) << Args[0]->getType() << DeletedFD; } // The user probably meant to call this special member. Just // explain why it's deleted. NoteDeletedFunction(DeletedFD); return ExprError(); } CandidateSet.NoteCandidates( PartialDiagnosticAt( OpLoc, PDiag(diag::err_ovl_deleted_oper) << getOperatorSpelling(Best->Function->getDeclName() .getCXXOverloadedOperator()) << Args[0]->getSourceRange() << Args[1]->getSourceRange()), *this, OCD_AllCandidates, Args, BinaryOperator::getOpcodeStr(Opc), OpLoc); return ExprError(); } // We matched a built-in operator; build it. return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]); } ExprResult Sema::BuildSynthesizedThreeWayComparison( SourceLocation OpLoc, const UnresolvedSetImpl &Fns, Expr *LHS, Expr *RHS, FunctionDecl *DefaultedFn) { const ComparisonCategoryInfo *Info = Context.CompCategories.lookupInfoForType(DefaultedFn->getReturnType()); // If we're not producing a known comparison category type, we can't // synthesize a three-way comparison. Let the caller diagnose this. if (!Info) return ExprResult((Expr*)nullptr); // If we ever want to perform this synthesis more generally, we will need to // apply the temporary materialization conversion to the operands. assert(LHS->isGLValue() && RHS->isGLValue() && "cannot use prvalue expressions more than once"); Expr *OrigLHS = LHS; Expr *OrigRHS = RHS; // Replace the LHS and RHS with OpaqueValueExprs; we're going to refer to // each of them multiple times below. LHS = new (Context) OpaqueValueExpr(LHS->getExprLoc(), LHS->getType(), LHS->getValueKind(), LHS->getObjectKind(), LHS); RHS = new (Context) OpaqueValueExpr(RHS->getExprLoc(), RHS->getType(), RHS->getValueKind(), RHS->getObjectKind(), RHS); ExprResult Eq = CreateOverloadedBinOp(OpLoc, BO_EQ, Fns, LHS, RHS, true, true, DefaultedFn); if (Eq.isInvalid()) return ExprError(); ExprResult Less = CreateOverloadedBinOp(OpLoc, BO_LT, Fns, LHS, RHS, true, true, DefaultedFn); if (Less.isInvalid()) return ExprError(); ExprResult Greater; if (Info->isPartial()) { Greater = CreateOverloadedBinOp(OpLoc, BO_LT, Fns, RHS, LHS, true, true, DefaultedFn); if (Greater.isInvalid()) return ExprError(); } // Form the list of comparisons we're going to perform. struct Comparison { ExprResult Cmp; ComparisonCategoryResult Result; } Comparisons[4] = { {Eq, Info->isStrong() ? ComparisonCategoryResult::Equal : ComparisonCategoryResult::Equivalent}, {Less, ComparisonCategoryResult::Less}, {Greater, ComparisonCategoryResult::Greater}, {ExprResult(), ComparisonCategoryResult::Unordered}, }; int I = Info->isPartial() ? 3 : 2; // Combine the comparisons with suitable conditional expressions. ExprResult Result; for (; I >= 0; --I) { // Build a reference to the comparison category constant. auto *VI = Info->lookupValueInfo(Comparisons[I].Result); // FIXME: Missing a constant for a comparison category. Diagnose this? if (!VI) return ExprResult((Expr*)nullptr); ExprResult ThisResult = BuildDeclarationNameExpr(CXXScopeSpec(), DeclarationNameInfo(), VI->VD); if (ThisResult.isInvalid()) return ExprError(); // Build a conditional unless this is the final case. if (Result.get()) { Result = ActOnConditionalOp(OpLoc, OpLoc, Comparisons[I].Cmp.get(), ThisResult.get(), Result.get()); if (Result.isInvalid()) return ExprError(); } else { Result = ThisResult; } } // Build a PseudoObjectExpr to model the rewriting of an <=> operator, and to // bind the OpaqueValueExprs before they're (repeatedly) used. Expr *SyntacticForm = BinaryOperator::Create( Context, OrigLHS, OrigRHS, BO_Cmp, Result.get()->getType(), Result.get()->getValueKind(), Result.get()->getObjectKind(), OpLoc, CurFPFeatureOverrides()); Expr *SemanticForm[] = {LHS, RHS, Result.get()}; return PseudoObjectExpr::Create(Context, SyntacticForm, SemanticForm, 2); } ExprResult Sema::CreateOverloadedArraySubscriptExpr(SourceLocation LLoc, SourceLocation RLoc, Expr *Base, Expr *Idx) { Expr *Args[2] = { Base, Idx }; DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(OO_Subscript); // If either side is type-dependent, create an appropriate dependent // expression. if (Args[0]->isTypeDependent() || Args[1]->isTypeDependent()) { CXXRecordDecl *NamingClass = nullptr; // lookup ignores member operators // CHECKME: no 'operator' keyword? DeclarationNameInfo OpNameInfo(OpName, LLoc); OpNameInfo.setCXXOperatorNameRange(SourceRange(LLoc, RLoc)); ExprResult Fn = CreateUnresolvedLookupExpr( NamingClass, NestedNameSpecifierLoc(), OpNameInfo, UnresolvedSet<0>()); if (Fn.isInvalid()) return ExprError(); // Can't add any actual overloads yet return CXXOperatorCallExpr::Create(Context, OO_Subscript, Fn.get(), Args, Context.DependentTy, VK_RValue, RLoc, CurFPFeatureOverrides()); } // Handle placeholders on both operands. if (checkPlaceholderForOverload(*this, Args[0])) return ExprError(); if (checkPlaceholderForOverload(*this, Args[1])) return ExprError(); // Build an empty overload set. OverloadCandidateSet CandidateSet(LLoc, OverloadCandidateSet::CSK_Operator); // Subscript can only be overloaded as a member function. // Add operator candidates that are member functions. AddMemberOperatorCandidates(OO_Subscript, LLoc, Args, CandidateSet); // Add builtin operator candidates. AddBuiltinOperatorCandidates(OO_Subscript, LLoc, Args, CandidateSet); bool HadMultipleCandidates = (CandidateSet.size() > 1); // Perform overload resolution. OverloadCandidateSet::iterator Best; switch (CandidateSet.BestViableFunction(*this, LLoc, Best)) { case OR_Success: { // We found a built-in operator or an overloaded operator. FunctionDecl *FnDecl = Best->Function; if (FnDecl) { // We matched an overloaded operator. Build a call to that // operator. CheckMemberOperatorAccess(LLoc, Args[0], Args[1], Best->FoundDecl); // Convert the arguments. CXXMethodDecl *Method = cast(FnDecl); ExprResult Arg0 = PerformObjectArgumentInitialization(Args[0], /*Qualifier=*/nullptr, Best->FoundDecl, Method); if (Arg0.isInvalid()) return ExprError(); Args[0] = Arg0.get(); // Convert the arguments. ExprResult InputInit = PerformCopyInitialization(InitializedEntity::InitializeParameter( Context, FnDecl->getParamDecl(0)), SourceLocation(), Args[1]); if (InputInit.isInvalid()) return ExprError(); Args[1] = InputInit.getAs(); // Build the actual expression node. DeclarationNameInfo OpLocInfo(OpName, LLoc); OpLocInfo.setCXXOperatorNameRange(SourceRange(LLoc, RLoc)); ExprResult FnExpr = CreateFunctionRefExpr(*this, FnDecl, Best->FoundDecl, Base, HadMultipleCandidates, OpLocInfo.getLoc(), OpLocInfo.getInfo()); if (FnExpr.isInvalid()) return ExprError(); // Determine the result type QualType ResultTy = FnDecl->getReturnType(); ExprValueKind VK = Expr::getValueKindForType(ResultTy); ResultTy = ResultTy.getNonLValueExprType(Context); CXXOperatorCallExpr *TheCall = CXXOperatorCallExpr::Create( Context, OO_Subscript, FnExpr.get(), Args, ResultTy, VK, RLoc, CurFPFeatureOverrides()); if (CheckCallReturnType(FnDecl->getReturnType(), LLoc, TheCall, FnDecl)) return ExprError(); if (CheckFunctionCall(Method, TheCall, Method->getType()->castAs())) return ExprError(); return MaybeBindToTemporary(TheCall); } else { // We matched a built-in operator. Convert the arguments, then // break out so that we will build the appropriate built-in // operator node. ExprResult ArgsRes0 = PerformImplicitConversion( Args[0], Best->BuiltinParamTypes[0], Best->Conversions[0], AA_Passing, CCK_ForBuiltinOverloadedOp); if (ArgsRes0.isInvalid()) return ExprError(); Args[0] = ArgsRes0.get(); ExprResult ArgsRes1 = PerformImplicitConversion( Args[1], Best->BuiltinParamTypes[1], Best->Conversions[1], AA_Passing, CCK_ForBuiltinOverloadedOp); if (ArgsRes1.isInvalid()) return ExprError(); Args[1] = ArgsRes1.get(); break; } } case OR_No_Viable_Function: { PartialDiagnostic PD = CandidateSet.empty() ? (PDiag(diag::err_ovl_no_oper) << Args[0]->getType() << /*subscript*/ 0 << Args[0]->getSourceRange() << Args[1]->getSourceRange()) : (PDiag(diag::err_ovl_no_viable_subscript) << Args[0]->getType() << Args[0]->getSourceRange() << Args[1]->getSourceRange()); CandidateSet.NoteCandidates(PartialDiagnosticAt(LLoc, PD), *this, OCD_AllCandidates, Args, "[]", LLoc); return ExprError(); } case OR_Ambiguous: CandidateSet.NoteCandidates( PartialDiagnosticAt(LLoc, PDiag(diag::err_ovl_ambiguous_oper_binary) << "[]" << Args[0]->getType() << Args[1]->getType() << Args[0]->getSourceRange() << Args[1]->getSourceRange()), *this, OCD_AmbiguousCandidates, Args, "[]", LLoc); return ExprError(); case OR_Deleted: CandidateSet.NoteCandidates( PartialDiagnosticAt(LLoc, PDiag(diag::err_ovl_deleted_oper) << "[]" << Args[0]->getSourceRange() << Args[1]->getSourceRange()), *this, OCD_AllCandidates, Args, "[]", LLoc); return ExprError(); } // We matched a built-in operator; build it. return CreateBuiltinArraySubscriptExpr(Args[0], LLoc, Args[1], RLoc); } /// BuildCallToMemberFunction - Build a call to a member /// function. MemExpr is the expression that refers to the member /// function (and includes the object parameter), Args/NumArgs are the /// arguments to the function call (not including the object /// parameter). The caller needs to validate that the member /// expression refers to a non-static member function or an overloaded /// member function. ExprResult Sema::BuildCallToMemberFunction(Scope *S, Expr *MemExprE, SourceLocation LParenLoc, MultiExprArg Args, SourceLocation RParenLoc, bool AllowRecovery) { assert(MemExprE->getType() == Context.BoundMemberTy || MemExprE->getType() == Context.OverloadTy); // Dig out the member expression. This holds both the object // argument and the member function we're referring to. Expr *NakedMemExpr = MemExprE->IgnoreParens(); // Determine whether this is a call to a pointer-to-member function. if (BinaryOperator *op = dyn_cast(NakedMemExpr)) { assert(op->getType() == Context.BoundMemberTy); assert(op->getOpcode() == BO_PtrMemD || op->getOpcode() == BO_PtrMemI); QualType fnType = op->getRHS()->getType()->castAs()->getPointeeType(); const FunctionProtoType *proto = fnType->castAs(); QualType resultType = proto->getCallResultType(Context); ExprValueKind valueKind = Expr::getValueKindForType(proto->getReturnType()); // Check that the object type isn't more qualified than the // member function we're calling. Qualifiers funcQuals = proto->getMethodQuals(); QualType objectType = op->getLHS()->getType(); if (op->getOpcode() == BO_PtrMemI) objectType = objectType->castAs()->getPointeeType(); Qualifiers objectQuals = objectType.getQualifiers(); Qualifiers difference = objectQuals - funcQuals; difference.removeObjCGCAttr(); difference.removeAddressSpace(); if (difference) { std::string qualsString = difference.getAsString(); Diag(LParenLoc, diag::err_pointer_to_member_call_drops_quals) << fnType.getUnqualifiedType() << qualsString << (qualsString.find(' ') == std::string::npos ? 1 : 2); } CXXMemberCallExpr *call = CXXMemberCallExpr::Create( Context, MemExprE, Args, resultType, valueKind, RParenLoc, CurFPFeatureOverrides(), proto->getNumParams()); if (CheckCallReturnType(proto->getReturnType(), op->getRHS()->getBeginLoc(), call, nullptr)) return ExprError(); if (ConvertArgumentsForCall(call, op, nullptr, proto, Args, RParenLoc)) return ExprError(); if (CheckOtherCall(call, proto)) return ExprError(); return MaybeBindToTemporary(call); } // We only try to build a recovery expr at this level if we can preserve // the return type, otherwise we return ExprError() and let the caller // recover. auto BuildRecoveryExpr = [&](QualType Type) { if (!AllowRecovery) return ExprError(); std::vector SubExprs = {MemExprE}; llvm::for_each(Args, [&SubExprs](Expr *E) { SubExprs.push_back(E); }); return CreateRecoveryExpr(MemExprE->getBeginLoc(), RParenLoc, SubExprs, Type); }; if (isa(NakedMemExpr)) return CallExpr::Create(Context, MemExprE, Args, Context.VoidTy, VK_RValue, RParenLoc, CurFPFeatureOverrides()); UnbridgedCastsSet UnbridgedCasts; if (checkArgPlaceholdersForOverload(*this, Args, UnbridgedCasts)) return ExprError(); MemberExpr *MemExpr; CXXMethodDecl *Method = nullptr; DeclAccessPair FoundDecl = DeclAccessPair::make(nullptr, AS_public); NestedNameSpecifier *Qualifier = nullptr; if (isa(NakedMemExpr)) { MemExpr = cast(NakedMemExpr); Method = cast(MemExpr->getMemberDecl()); FoundDecl = MemExpr->getFoundDecl(); Qualifier = MemExpr->getQualifier(); UnbridgedCasts.restore(); } else { UnresolvedMemberExpr *UnresExpr = cast(NakedMemExpr); Qualifier = UnresExpr->getQualifier(); QualType ObjectType = UnresExpr->getBaseType(); Expr::Classification ObjectClassification = UnresExpr->isArrow()? Expr::Classification::makeSimpleLValue() : UnresExpr->getBase()->Classify(Context); // Add overload candidates OverloadCandidateSet CandidateSet(UnresExpr->getMemberLoc(), OverloadCandidateSet::CSK_Normal); // FIXME: avoid copy. TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = nullptr; if (UnresExpr->hasExplicitTemplateArgs()) { UnresExpr->copyTemplateArgumentsInto(TemplateArgsBuffer); TemplateArgs = &TemplateArgsBuffer; } for (UnresolvedMemberExpr::decls_iterator I = UnresExpr->decls_begin(), E = UnresExpr->decls_end(); I != E; ++I) { NamedDecl *Func = *I; CXXRecordDecl *ActingDC = cast(Func->getDeclContext()); if (isa(Func)) Func = cast(Func)->getTargetDecl(); // Microsoft supports direct constructor calls. if (getLangOpts().MicrosoftExt && isa(Func)) { AddOverloadCandidate(cast(Func), I.getPair(), Args, CandidateSet, /*SuppressUserConversions*/ false); } else if ((Method = dyn_cast(Func))) { // If explicit template arguments were provided, we can't call a // non-template member function. if (TemplateArgs) continue; AddMethodCandidate(Method, I.getPair(), ActingDC, ObjectType, ObjectClassification, Args, CandidateSet, /*SuppressUserConversions=*/false); } else { AddMethodTemplateCandidate( cast(Func), I.getPair(), ActingDC, TemplateArgs, ObjectType, ObjectClassification, Args, CandidateSet, /*SuppressUserConversions=*/false); } } DeclarationName DeclName = UnresExpr->getMemberName(); UnbridgedCasts.restore(); OverloadCandidateSet::iterator Best; bool Succeeded = false; switch (CandidateSet.BestViableFunction(*this, UnresExpr->getBeginLoc(), Best)) { case OR_Success: Method = cast(Best->Function); FoundDecl = Best->FoundDecl; CheckUnresolvedMemberAccess(UnresExpr, Best->FoundDecl); if (DiagnoseUseOfDecl(Best->FoundDecl, UnresExpr->getNameLoc())) break; // If FoundDecl is different from Method (such as if one is a template // and the other a specialization), make sure DiagnoseUseOfDecl is // called on both. // FIXME: This would be more comprehensively addressed by modifying // DiagnoseUseOfDecl to accept both the FoundDecl and the decl // being used. if (Method != FoundDecl.getDecl() && DiagnoseUseOfDecl(Method, UnresExpr->getNameLoc())) break; Succeeded = true; break; case OR_No_Viable_Function: CandidateSet.NoteCandidates( PartialDiagnosticAt( UnresExpr->getMemberLoc(), PDiag(diag::err_ovl_no_viable_member_function_in_call) << DeclName << MemExprE->getSourceRange()), *this, OCD_AllCandidates, Args); break; case OR_Ambiguous: CandidateSet.NoteCandidates( PartialDiagnosticAt(UnresExpr->getMemberLoc(), PDiag(diag::err_ovl_ambiguous_member_call) << DeclName << MemExprE->getSourceRange()), *this, OCD_AmbiguousCandidates, Args); break; case OR_Deleted: CandidateSet.NoteCandidates( PartialDiagnosticAt(UnresExpr->getMemberLoc(), PDiag(diag::err_ovl_deleted_member_call) << DeclName << MemExprE->getSourceRange()), *this, OCD_AllCandidates, Args); break; } // Overload resolution fails, try to recover. if (!Succeeded) return BuildRecoveryExpr(chooseRecoveryType(CandidateSet, &Best)); MemExprE = FixOverloadedFunctionReference(MemExprE, FoundDecl, Method); // If overload resolution picked a static member, build a // non-member call based on that function. if (Method->isStatic()) { return BuildResolvedCallExpr(MemExprE, Method, LParenLoc, Args, RParenLoc); } MemExpr = cast(MemExprE->IgnoreParens()); } QualType ResultType = Method->getReturnType(); ExprValueKind VK = Expr::getValueKindForType(ResultType); ResultType = ResultType.getNonLValueExprType(Context); assert(Method && "Member call to something that isn't a method?"); const auto *Proto = Method->getType()->castAs(); CXXMemberCallExpr *TheCall = CXXMemberCallExpr::Create( Context, MemExprE, Args, ResultType, VK, RParenLoc, CurFPFeatureOverrides(), Proto->getNumParams()); // Check for a valid return type. if (CheckCallReturnType(Method->getReturnType(), MemExpr->getMemberLoc(), TheCall, Method)) return BuildRecoveryExpr(ResultType); // Convert the object argument (for a non-static member function call). // We only need to do this if there was actually an overload; otherwise // it was done at lookup. if (!Method->isStatic()) { ExprResult ObjectArg = PerformObjectArgumentInitialization(MemExpr->getBase(), Qualifier, FoundDecl, Method); if (ObjectArg.isInvalid()) return ExprError(); MemExpr->setBase(ObjectArg.get()); } // Convert the rest of the arguments if (ConvertArgumentsForCall(TheCall, MemExpr, Method, Proto, Args, RParenLoc)) return BuildRecoveryExpr(ResultType); DiagnoseSentinelCalls(Method, LParenLoc, Args); if (CheckFunctionCall(Method, TheCall, Proto)) return ExprError(); // In the case the method to call was not selected by the overloading // resolution process, we still need to handle the enable_if attribute. Do // that here, so it will not hide previous -- and more relevant -- errors. if (auto *MemE = dyn_cast(NakedMemExpr)) { if (const EnableIfAttr *Attr = CheckEnableIf(Method, LParenLoc, Args, true)) { Diag(MemE->getMemberLoc(), diag::err_ovl_no_viable_member_function_in_call) << Method << Method->getSourceRange(); Diag(Method->getLocation(), diag::note_ovl_candidate_disabled_by_function_cond_attr) << Attr->getCond()->getSourceRange() << Attr->getMessage(); return ExprError(); } } if ((isa(CurContext) || isa(CurContext)) && TheCall->getMethodDecl()->isPure()) { const CXXMethodDecl *MD = TheCall->getMethodDecl(); if (isa(MemExpr->getBase()->IgnoreParenCasts()) && MemExpr->performsVirtualDispatch(getLangOpts())) { Diag(MemExpr->getBeginLoc(), diag::warn_call_to_pure_virtual_member_function_from_ctor_dtor) << MD->getDeclName() << isa(CurContext) << MD->getParent(); Diag(MD->getBeginLoc(), diag::note_previous_decl) << MD->getDeclName(); if (getLangOpts().AppleKext) Diag(MemExpr->getBeginLoc(), diag::note_pure_qualified_call_kext) << MD->getParent() << MD->getDeclName(); } } if (CXXDestructorDecl *DD = dyn_cast(TheCall->getMethodDecl())) { // a->A::f() doesn't go through the vtable, except in AppleKext mode. bool CallCanBeVirtual = !MemExpr->hasQualifier() || getLangOpts().AppleKext; CheckVirtualDtorCall(DD, MemExpr->getBeginLoc(), /*IsDelete=*/false, CallCanBeVirtual, /*WarnOnNonAbstractTypes=*/true, MemExpr->getMemberLoc()); } return CheckForImmediateInvocation(MaybeBindToTemporary(TheCall), TheCall->getMethodDecl()); } /// BuildCallToObjectOfClassType - Build a call to an object of class /// type (C++ [over.call.object]), which can end up invoking an /// overloaded function call operator (@c operator()) or performing a /// user-defined conversion on the object argument. ExprResult Sema::BuildCallToObjectOfClassType(Scope *S, Expr *Obj, SourceLocation LParenLoc, MultiExprArg Args, SourceLocation RParenLoc) { if (checkPlaceholderForOverload(*this, Obj)) return ExprError(); ExprResult Object = Obj; UnbridgedCastsSet UnbridgedCasts; if (checkArgPlaceholdersForOverload(*this, Args, UnbridgedCasts)) return ExprError(); assert(Object.get()->getType()->isRecordType() && "Requires object type argument"); // C++ [over.call.object]p1: // If the primary-expression E in the function call syntax // evaluates to a class object of type "cv T", then the set of // candidate functions includes at least the function call // operators of T. The function call operators of T are obtained by // ordinary lookup of the name operator() in the context of // (E).operator(). OverloadCandidateSet CandidateSet(LParenLoc, OverloadCandidateSet::CSK_Operator); DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(OO_Call); if (RequireCompleteType(LParenLoc, Object.get()->getType(), diag::err_incomplete_object_call, Object.get())) return true; const auto *Record = Object.get()->getType()->castAs(); LookupResult R(*this, OpName, LParenLoc, LookupOrdinaryName); LookupQualifiedName(R, Record->getDecl()); R.suppressDiagnostics(); for (LookupResult::iterator Oper = R.begin(), OperEnd = R.end(); Oper != OperEnd; ++Oper) { AddMethodCandidate(Oper.getPair(), Object.get()->getType(), Object.get()->Classify(Context), Args, CandidateSet, /*SuppressUserConversion=*/false); } // C++ [over.call.object]p2: // In addition, for each (non-explicit in C++0x) conversion function // declared in T of the form // // operator conversion-type-id () cv-qualifier; // // where cv-qualifier is the same cv-qualification as, or a // greater cv-qualification than, cv, and where conversion-type-id // denotes the type "pointer to function of (P1,...,Pn) returning // R", or the type "reference to pointer to function of // (P1,...,Pn) returning R", or the type "reference to function // of (P1,...,Pn) returning R", a surrogate call function [...] // is also considered as a candidate function. Similarly, // surrogate call functions are added to the set of candidate // functions for each conversion function declared in an // accessible base class provided the function is not hidden // within T by another intervening declaration. const auto &Conversions = cast(Record->getDecl())->getVisibleConversionFunctions(); for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) { NamedDecl *D = *I; CXXRecordDecl *ActingContext = cast(D->getDeclContext()); if (isa(D)) D = cast(D)->getTargetDecl(); // Skip over templated conversion functions; they aren't // surrogates. if (isa(D)) continue; CXXConversionDecl *Conv = cast(D); if (!Conv->isExplicit()) { // Strip the reference type (if any) and then the pointer type (if // any) to get down to what might be a function type. QualType ConvType = Conv->getConversionType().getNonReferenceType(); if (const PointerType *ConvPtrType = ConvType->getAs()) ConvType = ConvPtrType->getPointeeType(); if (const FunctionProtoType *Proto = ConvType->getAs()) { AddSurrogateCandidate(Conv, I.getPair(), ActingContext, Proto, Object.get(), Args, CandidateSet); } } } bool HadMultipleCandidates = (CandidateSet.size() > 1); // Perform overload resolution. OverloadCandidateSet::iterator Best; switch (CandidateSet.BestViableFunction(*this, Object.get()->getBeginLoc(), Best)) { case OR_Success: // Overload resolution succeeded; we'll build the appropriate call // below. break; case OR_No_Viable_Function: { PartialDiagnostic PD = CandidateSet.empty() ? (PDiag(diag::err_ovl_no_oper) << Object.get()->getType() << /*call*/ 1 << Object.get()->getSourceRange()) : (PDiag(diag::err_ovl_no_viable_object_call) << Object.get()->getType() << Object.get()->getSourceRange()); CandidateSet.NoteCandidates( PartialDiagnosticAt(Object.get()->getBeginLoc(), PD), *this, OCD_AllCandidates, Args); break; } case OR_Ambiguous: CandidateSet.NoteCandidates( PartialDiagnosticAt(Object.get()->getBeginLoc(), PDiag(diag::err_ovl_ambiguous_object_call) << Object.get()->getType() << Object.get()->getSourceRange()), *this, OCD_AmbiguousCandidates, Args); break; case OR_Deleted: CandidateSet.NoteCandidates( PartialDiagnosticAt(Object.get()->getBeginLoc(), PDiag(diag::err_ovl_deleted_object_call) << Object.get()->getType() << Object.get()->getSourceRange()), *this, OCD_AllCandidates, Args); break; } if (Best == CandidateSet.end()) return true; UnbridgedCasts.restore(); if (Best->Function == nullptr) { // Since there is no function declaration, this is one of the // surrogate candidates. Dig out the conversion function. CXXConversionDecl *Conv = cast( Best->Conversions[0].UserDefined.ConversionFunction); CheckMemberOperatorAccess(LParenLoc, Object.get(), nullptr, Best->FoundDecl); if (DiagnoseUseOfDecl(Best->FoundDecl, LParenLoc)) return ExprError(); assert(Conv == Best->FoundDecl.getDecl() && "Found Decl & conversion-to-functionptr should be same, right?!"); // We selected one of the surrogate functions that converts the // object parameter to a function pointer. Perform the conversion // on the object argument, then let BuildCallExpr finish the job. // Create an implicit member expr to refer to the conversion operator. // and then call it. ExprResult Call = BuildCXXMemberCallExpr(Object.get(), Best->FoundDecl, Conv, HadMultipleCandidates); if (Call.isInvalid()) return ExprError(); // Record usage of conversion in an implicit cast. Call = ImplicitCastExpr::Create( Context, Call.get()->getType(), CK_UserDefinedConversion, Call.get(), nullptr, VK_RValue, CurFPFeatureOverrides()); return BuildCallExpr(S, Call.get(), LParenLoc, Args, RParenLoc); } CheckMemberOperatorAccess(LParenLoc, Object.get(), nullptr, Best->FoundDecl); // We found an overloaded operator(). Build a CXXOperatorCallExpr // that calls this method, using Object for the implicit object // parameter and passing along the remaining arguments. CXXMethodDecl *Method = cast(Best->Function); // An error diagnostic has already been printed when parsing the declaration. if (Method->isInvalidDecl()) return ExprError(); const auto *Proto = Method->getType()->castAs(); unsigned NumParams = Proto->getNumParams(); DeclarationNameInfo OpLocInfo( Context.DeclarationNames.getCXXOperatorName(OO_Call), LParenLoc); OpLocInfo.setCXXOperatorNameRange(SourceRange(LParenLoc, RParenLoc)); ExprResult NewFn = CreateFunctionRefExpr(*this, Method, Best->FoundDecl, Obj, HadMultipleCandidates, OpLocInfo.getLoc(), OpLocInfo.getInfo()); if (NewFn.isInvalid()) return true; // The number of argument slots to allocate in the call. If we have default // arguments we need to allocate space for them as well. We additionally // need one more slot for the object parameter. unsigned NumArgsSlots = 1 + std::max(Args.size(), NumParams); // Build the full argument list for the method call (the implicit object // parameter is placed at the beginning of the list). SmallVector MethodArgs(NumArgsSlots); bool IsError = false; // Initialize the implicit object parameter. ExprResult ObjRes = PerformObjectArgumentInitialization(Object.get(), /*Qualifier=*/nullptr, Best->FoundDecl, Method); if (ObjRes.isInvalid()) IsError = true; else Object = ObjRes; MethodArgs[0] = Object.get(); // Check the argument types. for (unsigned i = 0; i != NumParams; i++) { Expr *Arg; if (i < Args.size()) { Arg = Args[i]; // Pass the argument. ExprResult InputInit = PerformCopyInitialization(InitializedEntity::InitializeParameter( Context, Method->getParamDecl(i)), SourceLocation(), Arg); IsError |= InputInit.isInvalid(); Arg = InputInit.getAs(); } else { ExprResult DefArg = BuildCXXDefaultArgExpr(LParenLoc, Method, Method->getParamDecl(i)); if (DefArg.isInvalid()) { IsError = true; break; } Arg = DefArg.getAs(); } MethodArgs[i + 1] = Arg; } // If this is a variadic call, handle args passed through "...". if (Proto->isVariadic()) { // Promote the arguments (C99 6.5.2.2p7). for (unsigned i = NumParams, e = Args.size(); i < e; i++) { ExprResult Arg = DefaultVariadicArgumentPromotion(Args[i], VariadicMethod, nullptr); IsError |= Arg.isInvalid(); MethodArgs[i + 1] = Arg.get(); } } if (IsError) return true; DiagnoseSentinelCalls(Method, LParenLoc, Args); // Once we've built TheCall, all of the expressions are properly owned. QualType ResultTy = Method->getReturnType(); ExprValueKind VK = Expr::getValueKindForType(ResultTy); ResultTy = ResultTy.getNonLValueExprType(Context); CXXOperatorCallExpr *TheCall = CXXOperatorCallExpr::Create( Context, OO_Call, NewFn.get(), MethodArgs, ResultTy, VK, RParenLoc, CurFPFeatureOverrides()); if (CheckCallReturnType(Method->getReturnType(), LParenLoc, TheCall, Method)) return true; if (CheckFunctionCall(Method, TheCall, Proto)) return true; return CheckForImmediateInvocation(MaybeBindToTemporary(TheCall), Method); } /// BuildOverloadedArrowExpr - Build a call to an overloaded @c operator-> /// (if one exists), where @c Base is an expression of class type and /// @c Member is the name of the member we're trying to find. ExprResult Sema::BuildOverloadedArrowExpr(Scope *S, Expr *Base, SourceLocation OpLoc, bool *NoArrowOperatorFound) { assert(Base->getType()->isRecordType() && "left-hand side must have class type"); if (checkPlaceholderForOverload(*this, Base)) return ExprError(); SourceLocation Loc = Base->getExprLoc(); // C++ [over.ref]p1: // // [...] An expression x->m is interpreted as (x.operator->())->m // for a class object x of type T if T::operator->() exists and if // the operator is selected as the best match function by the // overload resolution mechanism (13.3). DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(OO_Arrow); OverloadCandidateSet CandidateSet(Loc, OverloadCandidateSet::CSK_Operator); if (RequireCompleteType(Loc, Base->getType(), diag::err_typecheck_incomplete_tag, Base)) return ExprError(); LookupResult R(*this, OpName, OpLoc, LookupOrdinaryName); LookupQualifiedName(R, Base->getType()->castAs()->getDecl()); R.suppressDiagnostics(); for (LookupResult::iterator Oper = R.begin(), OperEnd = R.end(); Oper != OperEnd; ++Oper) { AddMethodCandidate(Oper.getPair(), Base->getType(), Base->Classify(Context), None, CandidateSet, /*SuppressUserConversion=*/false); } bool HadMultipleCandidates = (CandidateSet.size() > 1); // Perform overload resolution. OverloadCandidateSet::iterator Best; switch (CandidateSet.BestViableFunction(*this, OpLoc, Best)) { case OR_Success: // Overload resolution succeeded; we'll build the call below. break; case OR_No_Viable_Function: { auto Cands = CandidateSet.CompleteCandidates(*this, OCD_AllCandidates, Base); if (CandidateSet.empty()) { QualType BaseType = Base->getType(); if (NoArrowOperatorFound) { // Report this specific error to the caller instead of emitting a // diagnostic, as requested. *NoArrowOperatorFound = true; return ExprError(); } Diag(OpLoc, diag::err_typecheck_member_reference_arrow) << BaseType << Base->getSourceRange(); if (BaseType->isRecordType() && !BaseType->isPointerType()) { Diag(OpLoc, diag::note_typecheck_member_reference_suggestion) << FixItHint::CreateReplacement(OpLoc, "."); } } else Diag(OpLoc, diag::err_ovl_no_viable_oper) << "operator->" << Base->getSourceRange(); CandidateSet.NoteCandidates(*this, Base, Cands); return ExprError(); } case OR_Ambiguous: CandidateSet.NoteCandidates( PartialDiagnosticAt(OpLoc, PDiag(diag::err_ovl_ambiguous_oper_unary) << "->" << Base->getType() << Base->getSourceRange()), *this, OCD_AmbiguousCandidates, Base); return ExprError(); case OR_Deleted: CandidateSet.NoteCandidates( PartialDiagnosticAt(OpLoc, PDiag(diag::err_ovl_deleted_oper) << "->" << Base->getSourceRange()), *this, OCD_AllCandidates, Base); return ExprError(); } CheckMemberOperatorAccess(OpLoc, Base, nullptr, Best->FoundDecl); // Convert the object parameter. CXXMethodDecl *Method = cast(Best->Function); ExprResult BaseResult = PerformObjectArgumentInitialization(Base, /*Qualifier=*/nullptr, Best->FoundDecl, Method); if (BaseResult.isInvalid()) return ExprError(); Base = BaseResult.get(); // Build the operator call. ExprResult FnExpr = CreateFunctionRefExpr(*this, Method, Best->FoundDecl, Base, HadMultipleCandidates, OpLoc); if (FnExpr.isInvalid()) return ExprError(); QualType ResultTy = Method->getReturnType(); ExprValueKind VK = Expr::getValueKindForType(ResultTy); ResultTy = ResultTy.getNonLValueExprType(Context); CXXOperatorCallExpr *TheCall = CXXOperatorCallExpr::Create(Context, OO_Arrow, FnExpr.get(), Base, ResultTy, VK, OpLoc, CurFPFeatureOverrides()); if (CheckCallReturnType(Method->getReturnType(), OpLoc, TheCall, Method)) return ExprError(); if (CheckFunctionCall(Method, TheCall, Method->getType()->castAs())) return ExprError(); return MaybeBindToTemporary(TheCall); } /// BuildLiteralOperatorCall - Build a UserDefinedLiteral by creating a call to /// a literal operator described by the provided lookup results. ExprResult Sema::BuildLiteralOperatorCall(LookupResult &R, DeclarationNameInfo &SuffixInfo, ArrayRef Args, SourceLocation LitEndLoc, TemplateArgumentListInfo *TemplateArgs) { SourceLocation UDSuffixLoc = SuffixInfo.getCXXLiteralOperatorNameLoc(); OverloadCandidateSet CandidateSet(UDSuffixLoc, OverloadCandidateSet::CSK_Normal); AddNonMemberOperatorCandidates(R.asUnresolvedSet(), Args, CandidateSet, TemplateArgs); bool HadMultipleCandidates = (CandidateSet.size() > 1); // Perform overload resolution. This will usually be trivial, but might need // to perform substitutions for a literal operator template. OverloadCandidateSet::iterator Best; switch (CandidateSet.BestViableFunction(*this, UDSuffixLoc, Best)) { case OR_Success: case OR_Deleted: break; case OR_No_Viable_Function: CandidateSet.NoteCandidates( PartialDiagnosticAt(UDSuffixLoc, PDiag(diag::err_ovl_no_viable_function_in_call) << R.getLookupName()), *this, OCD_AllCandidates, Args); return ExprError(); case OR_Ambiguous: CandidateSet.NoteCandidates( PartialDiagnosticAt(R.getNameLoc(), PDiag(diag::err_ovl_ambiguous_call) << R.getLookupName()), *this, OCD_AmbiguousCandidates, Args); return ExprError(); } FunctionDecl *FD = Best->Function; ExprResult Fn = CreateFunctionRefExpr(*this, FD, Best->FoundDecl, nullptr, HadMultipleCandidates, SuffixInfo.getLoc(), SuffixInfo.getInfo()); if (Fn.isInvalid()) return true; // Check the argument types. This should almost always be a no-op, except // that array-to-pointer decay is applied to string literals. Expr *ConvArgs[2]; for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) { ExprResult InputInit = PerformCopyInitialization( InitializedEntity::InitializeParameter(Context, FD->getParamDecl(ArgIdx)), SourceLocation(), Args[ArgIdx]); if (InputInit.isInvalid()) return true; ConvArgs[ArgIdx] = InputInit.get(); } QualType ResultTy = FD->getReturnType(); ExprValueKind VK = Expr::getValueKindForType(ResultTy); ResultTy = ResultTy.getNonLValueExprType(Context); UserDefinedLiteral *UDL = UserDefinedLiteral::Create( Context, Fn.get(), llvm::makeArrayRef(ConvArgs, Args.size()), ResultTy, VK, LitEndLoc, UDSuffixLoc, CurFPFeatureOverrides()); if (CheckCallReturnType(FD->getReturnType(), UDSuffixLoc, UDL, FD)) return ExprError(); if (CheckFunctionCall(FD, UDL, nullptr)) return ExprError(); return CheckForImmediateInvocation(MaybeBindToTemporary(UDL), FD); } /// Build a call to 'begin' or 'end' for a C++11 for-range statement. If the /// given LookupResult is non-empty, it is assumed to describe a member which /// will be invoked. Otherwise, the function will be found via argument /// dependent lookup. /// CallExpr is set to a valid expression and FRS_Success returned on success, /// otherwise CallExpr is set to ExprError() and some non-success value /// is returned. Sema::ForRangeStatus Sema::BuildForRangeBeginEndCall(SourceLocation Loc, SourceLocation RangeLoc, const DeclarationNameInfo &NameInfo, LookupResult &MemberLookup, OverloadCandidateSet *CandidateSet, Expr *Range, ExprResult *CallExpr) { Scope *S = nullptr; CandidateSet->clear(OverloadCandidateSet::CSK_Normal); if (!MemberLookup.empty()) { ExprResult MemberRef = BuildMemberReferenceExpr(Range, Range->getType(), Loc, /*IsPtr=*/false, CXXScopeSpec(), /*TemplateKWLoc=*/SourceLocation(), /*FirstQualifierInScope=*/nullptr, MemberLookup, /*TemplateArgs=*/nullptr, S); if (MemberRef.isInvalid()) { *CallExpr = ExprError(); return FRS_DiagnosticIssued; } *CallExpr = BuildCallExpr(S, MemberRef.get(), Loc, None, Loc, nullptr); if (CallExpr->isInvalid()) { *CallExpr = ExprError(); return FRS_DiagnosticIssued; } } else { ExprResult FnR = CreateUnresolvedLookupExpr(/*NamingClass=*/nullptr, NestedNameSpecifierLoc(), NameInfo, UnresolvedSet<0>()); if (FnR.isInvalid()) return FRS_DiagnosticIssued; UnresolvedLookupExpr *Fn = cast(FnR.get()); bool CandidateSetError = buildOverloadedCallSet(S, Fn, Fn, Range, Loc, CandidateSet, CallExpr); if (CandidateSet->empty() || CandidateSetError) { *CallExpr = ExprError(); return FRS_NoViableFunction; } OverloadCandidateSet::iterator Best; OverloadingResult OverloadResult = CandidateSet->BestViableFunction(*this, Fn->getBeginLoc(), Best); if (OverloadResult == OR_No_Viable_Function) { *CallExpr = ExprError(); return FRS_NoViableFunction; } *CallExpr = FinishOverloadedCallExpr(*this, S, Fn, Fn, Loc, Range, Loc, nullptr, CandidateSet, &Best, OverloadResult, /*AllowTypoCorrection=*/false); if (CallExpr->isInvalid() || OverloadResult != OR_Success) { *CallExpr = ExprError(); return FRS_DiagnosticIssued; } } return FRS_Success; } /// FixOverloadedFunctionReference - E is an expression that refers to /// a C++ overloaded function (possibly with some parentheses and /// perhaps a '&' around it). We have resolved the overloaded function /// to the function declaration Fn, so patch up the expression E to /// refer (possibly indirectly) to Fn. Returns the new expr. Expr *Sema::FixOverloadedFunctionReference(Expr *E, DeclAccessPair Found, FunctionDecl *Fn) { if (ParenExpr *PE = dyn_cast(E)) { Expr *SubExpr = FixOverloadedFunctionReference(PE->getSubExpr(), Found, Fn); if (SubExpr == PE->getSubExpr()) return PE; return new (Context) ParenExpr(PE->getLParen(), PE->getRParen(), SubExpr); } if (ImplicitCastExpr *ICE = dyn_cast(E)) { Expr *SubExpr = FixOverloadedFunctionReference(ICE->getSubExpr(), Found, Fn); assert(Context.hasSameType(ICE->getSubExpr()->getType(), SubExpr->getType()) && "Implicit cast type cannot be determined from overload"); assert(ICE->path_empty() && "fixing up hierarchy conversion?"); if (SubExpr == ICE->getSubExpr()) return ICE; return ImplicitCastExpr::Create(Context, ICE->getType(), ICE->getCastKind(), SubExpr, nullptr, ICE->getValueKind(), CurFPFeatureOverrides()); } if (auto *GSE = dyn_cast(E)) { if (!GSE->isResultDependent()) { Expr *SubExpr = FixOverloadedFunctionReference(GSE->getResultExpr(), Found, Fn); if (SubExpr == GSE->getResultExpr()) return GSE; // Replace the resulting type information before rebuilding the generic // selection expression. ArrayRef A = GSE->getAssocExprs(); SmallVector AssocExprs(A.begin(), A.end()); unsigned ResultIdx = GSE->getResultIndex(); AssocExprs[ResultIdx] = SubExpr; return GenericSelectionExpr::Create( Context, GSE->getGenericLoc(), GSE->getControllingExpr(), GSE->getAssocTypeSourceInfos(), AssocExprs, GSE->getDefaultLoc(), GSE->getRParenLoc(), GSE->containsUnexpandedParameterPack(), ResultIdx); } // Rather than fall through to the unreachable, return the original generic // selection expression. return GSE; } if (UnaryOperator *UnOp = dyn_cast(E)) { assert(UnOp->getOpcode() == UO_AddrOf && "Can only take the address of an overloaded function"); if (CXXMethodDecl *Method = dyn_cast(Fn)) { if (Method->isStatic()) { // Do nothing: static member functions aren't any different // from non-member functions. } else { // Fix the subexpression, which really has to be an // UnresolvedLookupExpr holding an overloaded member function // or template. Expr *SubExpr = FixOverloadedFunctionReference(UnOp->getSubExpr(), Found, Fn); if (SubExpr == UnOp->getSubExpr()) return UnOp; assert(isa(SubExpr) && "fixed to something other than a decl ref"); assert(cast(SubExpr)->getQualifier() && "fixed to a member ref with no nested name qualifier"); // We have taken the address of a pointer to member // function. Perform the computation here so that we get the // appropriate pointer to member type. QualType ClassType = Context.getTypeDeclType(cast(Method->getDeclContext())); QualType MemPtrType = Context.getMemberPointerType(Fn->getType(), ClassType.getTypePtr()); // Under the MS ABI, lock down the inheritance model now. if (Context.getTargetInfo().getCXXABI().isMicrosoft()) (void)isCompleteType(UnOp->getOperatorLoc(), MemPtrType); return UnaryOperator::Create( Context, SubExpr, UO_AddrOf, MemPtrType, VK_RValue, OK_Ordinary, UnOp->getOperatorLoc(), false, CurFPFeatureOverrides()); } } Expr *SubExpr = FixOverloadedFunctionReference(UnOp->getSubExpr(), Found, Fn); if (SubExpr == UnOp->getSubExpr()) return UnOp; return UnaryOperator::Create(Context, SubExpr, UO_AddrOf, Context.getPointerType(SubExpr->getType()), VK_RValue, OK_Ordinary, UnOp->getOperatorLoc(), false, CurFPFeatureOverrides()); } if (UnresolvedLookupExpr *ULE = dyn_cast(E)) { // FIXME: avoid copy. TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = nullptr; if (ULE->hasExplicitTemplateArgs()) { ULE->copyTemplateArgumentsInto(TemplateArgsBuffer); TemplateArgs = &TemplateArgsBuffer; } DeclRefExpr *DRE = BuildDeclRefExpr(Fn, Fn->getType(), VK_LValue, ULE->getNameInfo(), ULE->getQualifierLoc(), Found.getDecl(), ULE->getTemplateKeywordLoc(), TemplateArgs); DRE->setHadMultipleCandidates(ULE->getNumDecls() > 1); return DRE; } if (UnresolvedMemberExpr *MemExpr = dyn_cast(E)) { // FIXME: avoid copy. TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = nullptr; if (MemExpr->hasExplicitTemplateArgs()) { MemExpr->copyTemplateArgumentsInto(TemplateArgsBuffer); TemplateArgs = &TemplateArgsBuffer; } Expr *Base; // If we're filling in a static method where we used to have an // implicit member access, rewrite to a simple decl ref. if (MemExpr->isImplicitAccess()) { if (cast(Fn)->isStatic()) { DeclRefExpr *DRE = BuildDeclRefExpr( Fn, Fn->getType(), VK_LValue, MemExpr->getNameInfo(), MemExpr->getQualifierLoc(), Found.getDecl(), MemExpr->getTemplateKeywordLoc(), TemplateArgs); DRE->setHadMultipleCandidates(MemExpr->getNumDecls() > 1); return DRE; } else { SourceLocation Loc = MemExpr->getMemberLoc(); if (MemExpr->getQualifier()) Loc = MemExpr->getQualifierLoc().getBeginLoc(); Base = BuildCXXThisExpr(Loc, MemExpr->getBaseType(), /*IsImplicit=*/true); } } else Base = MemExpr->getBase(); ExprValueKind valueKind; QualType type; if (cast(Fn)->isStatic()) { valueKind = VK_LValue; type = Fn->getType(); } else { valueKind = VK_RValue; type = Context.BoundMemberTy; } return BuildMemberExpr( Base, MemExpr->isArrow(), MemExpr->getOperatorLoc(), MemExpr->getQualifierLoc(), MemExpr->getTemplateKeywordLoc(), Fn, Found, /*HadMultipleCandidates=*/true, MemExpr->getMemberNameInfo(), type, valueKind, OK_Ordinary, TemplateArgs); } llvm_unreachable("Invalid reference to overloaded function"); } ExprResult Sema::FixOverloadedFunctionReference(ExprResult E, DeclAccessPair Found, FunctionDecl *Fn) { return FixOverloadedFunctionReference(E.get(), Found, Fn); }