//===--- CGAtomic.cpp - Emit LLVM IR for atomic operations ----------------===// // // 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 contains the code for emitting atomic operations. // //===----------------------------------------------------------------------===// #include "CGCall.h" #include "CGRecordLayout.h" #include "CodeGenFunction.h" #include "CodeGenModule.h" #include "TargetInfo.h" #include "clang/AST/ASTContext.h" #include "clang/CodeGen/CGFunctionInfo.h" #include "clang/Frontend/FrontendDiagnostic.h" #include "llvm/ADT/DenseMap.h" #include "llvm/IR/DataLayout.h" #include "llvm/IR/Intrinsics.h" #include "llvm/IR/Operator.h" using namespace clang; using namespace CodeGen; namespace { class AtomicInfo { CodeGenFunction &CGF; QualType AtomicTy; QualType ValueTy; uint64_t AtomicSizeInBits; uint64_t ValueSizeInBits; CharUnits AtomicAlign; CharUnits ValueAlign; TypeEvaluationKind EvaluationKind; bool UseLibcall; LValue LVal; CGBitFieldInfo BFI; public: AtomicInfo(CodeGenFunction &CGF, LValue &lvalue) : CGF(CGF), AtomicSizeInBits(0), ValueSizeInBits(0), EvaluationKind(TEK_Scalar), UseLibcall(true) { assert(!lvalue.isGlobalReg()); ASTContext &C = CGF.getContext(); if (lvalue.isSimple()) { AtomicTy = lvalue.getType(); if (auto *ATy = AtomicTy->getAs()) ValueTy = ATy->getValueType(); else ValueTy = AtomicTy; EvaluationKind = CGF.getEvaluationKind(ValueTy); uint64_t ValueAlignInBits; uint64_t AtomicAlignInBits; TypeInfo ValueTI = C.getTypeInfo(ValueTy); ValueSizeInBits = ValueTI.Width; ValueAlignInBits = ValueTI.Align; TypeInfo AtomicTI = C.getTypeInfo(AtomicTy); AtomicSizeInBits = AtomicTI.Width; AtomicAlignInBits = AtomicTI.Align; assert(ValueSizeInBits <= AtomicSizeInBits); assert(ValueAlignInBits <= AtomicAlignInBits); AtomicAlign = C.toCharUnitsFromBits(AtomicAlignInBits); ValueAlign = C.toCharUnitsFromBits(ValueAlignInBits); if (lvalue.getAlignment().isZero()) lvalue.setAlignment(AtomicAlign); LVal = lvalue; } else if (lvalue.isBitField()) { ValueTy = lvalue.getType(); ValueSizeInBits = C.getTypeSize(ValueTy); auto &OrigBFI = lvalue.getBitFieldInfo(); auto Offset = OrigBFI.Offset % C.toBits(lvalue.getAlignment()); AtomicSizeInBits = C.toBits( C.toCharUnitsFromBits(Offset + OrigBFI.Size + C.getCharWidth() - 1) .alignTo(lvalue.getAlignment())); auto VoidPtrAddr = CGF.EmitCastToVoidPtr(lvalue.getBitFieldPointer()); auto OffsetInChars = (C.toCharUnitsFromBits(OrigBFI.Offset) / lvalue.getAlignment()) * lvalue.getAlignment(); VoidPtrAddr = CGF.Builder.CreateConstGEP1_64( VoidPtrAddr, OffsetInChars.getQuantity()); auto Addr = CGF.Builder.CreatePointerBitCastOrAddrSpaceCast( VoidPtrAddr, CGF.Builder.getIntNTy(AtomicSizeInBits)->getPointerTo(), "atomic_bitfield_base"); BFI = OrigBFI; BFI.Offset = Offset; BFI.StorageSize = AtomicSizeInBits; BFI.StorageOffset += OffsetInChars; LVal = LValue::MakeBitfield(Address(Addr, lvalue.getAlignment()), BFI, lvalue.getType(), lvalue.getBaseInfo(), lvalue.getTBAAInfo()); AtomicTy = C.getIntTypeForBitwidth(AtomicSizeInBits, OrigBFI.IsSigned); if (AtomicTy.isNull()) { llvm::APInt Size( /*numBits=*/32, C.toCharUnitsFromBits(AtomicSizeInBits).getQuantity()); AtomicTy = C.getConstantArrayType(C.CharTy, Size, nullptr, ArrayType::Normal, /*IndexTypeQuals=*/0); } AtomicAlign = ValueAlign = lvalue.getAlignment(); } else if (lvalue.isVectorElt()) { ValueTy = lvalue.getType()->castAs()->getElementType(); ValueSizeInBits = C.getTypeSize(ValueTy); AtomicTy = lvalue.getType(); AtomicSizeInBits = C.getTypeSize(AtomicTy); AtomicAlign = ValueAlign = lvalue.getAlignment(); LVal = lvalue; } else { assert(lvalue.isExtVectorElt()); ValueTy = lvalue.getType(); ValueSizeInBits = C.getTypeSize(ValueTy); AtomicTy = ValueTy = CGF.getContext().getExtVectorType( lvalue.getType(), cast( lvalue.getExtVectorAddress().getElementType()) ->getNumElements()); AtomicSizeInBits = C.getTypeSize(AtomicTy); AtomicAlign = ValueAlign = lvalue.getAlignment(); LVal = lvalue; } UseLibcall = !C.getTargetInfo().hasBuiltinAtomic( AtomicSizeInBits, C.toBits(lvalue.getAlignment())); } QualType getAtomicType() const { return AtomicTy; } QualType getValueType() const { return ValueTy; } CharUnits getAtomicAlignment() const { return AtomicAlign; } uint64_t getAtomicSizeInBits() const { return AtomicSizeInBits; } uint64_t getValueSizeInBits() const { return ValueSizeInBits; } TypeEvaluationKind getEvaluationKind() const { return EvaluationKind; } bool shouldUseLibcall() const { return UseLibcall; } const LValue &getAtomicLValue() const { return LVal; } llvm::Value *getAtomicPointer() const { if (LVal.isSimple()) return LVal.getPointer(CGF); else if (LVal.isBitField()) return LVal.getBitFieldPointer(); else if (LVal.isVectorElt()) return LVal.getVectorPointer(); assert(LVal.isExtVectorElt()); return LVal.getExtVectorPointer(); } Address getAtomicAddress() const { return Address(getAtomicPointer(), getAtomicAlignment()); } Address getAtomicAddressAsAtomicIntPointer() const { return emitCastToAtomicIntPointer(getAtomicAddress()); } /// Is the atomic size larger than the underlying value type? /// /// Note that the absence of padding does not mean that atomic /// objects are completely interchangeable with non-atomic /// objects: we might have promoted the alignment of a type /// without making it bigger. bool hasPadding() const { return (ValueSizeInBits != AtomicSizeInBits); } bool emitMemSetZeroIfNecessary() const; llvm::Value *getAtomicSizeValue() const { CharUnits size = CGF.getContext().toCharUnitsFromBits(AtomicSizeInBits); return CGF.CGM.getSize(size); } /// Cast the given pointer to an integer pointer suitable for atomic /// operations if the source. Address emitCastToAtomicIntPointer(Address Addr) const; /// If Addr is compatible with the iN that will be used for an atomic /// operation, bitcast it. Otherwise, create a temporary that is suitable /// and copy the value across. Address convertToAtomicIntPointer(Address Addr) const; /// Turn an atomic-layout object into an r-value. RValue convertAtomicTempToRValue(Address addr, AggValueSlot resultSlot, SourceLocation loc, bool AsValue) const; /// Converts a rvalue to integer value. llvm::Value *convertRValueToInt(RValue RVal) const; RValue ConvertIntToValueOrAtomic(llvm::Value *IntVal, AggValueSlot ResultSlot, SourceLocation Loc, bool AsValue) const; /// Copy an atomic r-value into atomic-layout memory. void emitCopyIntoMemory(RValue rvalue) const; /// Project an l-value down to the value field. LValue projectValue() const { assert(LVal.isSimple()); Address addr = getAtomicAddress(); if (hasPadding()) addr = CGF.Builder.CreateStructGEP(addr, 0); return LValue::MakeAddr(addr, getValueType(), CGF.getContext(), LVal.getBaseInfo(), LVal.getTBAAInfo()); } /// Emits atomic load. /// \returns Loaded value. RValue EmitAtomicLoad(AggValueSlot ResultSlot, SourceLocation Loc, bool AsValue, llvm::AtomicOrdering AO, bool IsVolatile); /// Emits atomic compare-and-exchange sequence. /// \param Expected Expected value. /// \param Desired Desired value. /// \param Success Atomic ordering for success operation. /// \param Failure Atomic ordering for failed operation. /// \param IsWeak true if atomic operation is weak, false otherwise. /// \returns Pair of values: previous value from storage (value type) and /// boolean flag (i1 type) with true if success and false otherwise. std::pair EmitAtomicCompareExchange(RValue Expected, RValue Desired, llvm::AtomicOrdering Success = llvm::AtomicOrdering::SequentiallyConsistent, llvm::AtomicOrdering Failure = llvm::AtomicOrdering::SequentiallyConsistent, bool IsWeak = false); /// Emits atomic update. /// \param AO Atomic ordering. /// \param UpdateOp Update operation for the current lvalue. void EmitAtomicUpdate(llvm::AtomicOrdering AO, const llvm::function_ref &UpdateOp, bool IsVolatile); /// Emits atomic update. /// \param AO Atomic ordering. void EmitAtomicUpdate(llvm::AtomicOrdering AO, RValue UpdateRVal, bool IsVolatile); /// Materialize an atomic r-value in atomic-layout memory. Address materializeRValue(RValue rvalue) const; /// Creates temp alloca for intermediate operations on atomic value. Address CreateTempAlloca() const; private: bool requiresMemSetZero(llvm::Type *type) const; /// Emits atomic load as a libcall. void EmitAtomicLoadLibcall(llvm::Value *AddForLoaded, llvm::AtomicOrdering AO, bool IsVolatile); /// Emits atomic load as LLVM instruction. llvm::Value *EmitAtomicLoadOp(llvm::AtomicOrdering AO, bool IsVolatile); /// Emits atomic compare-and-exchange op as a libcall. llvm::Value *EmitAtomicCompareExchangeLibcall( llvm::Value *ExpectedAddr, llvm::Value *DesiredAddr, llvm::AtomicOrdering Success = llvm::AtomicOrdering::SequentiallyConsistent, llvm::AtomicOrdering Failure = llvm::AtomicOrdering::SequentiallyConsistent); /// Emits atomic compare-and-exchange op as LLVM instruction. std::pair EmitAtomicCompareExchangeOp( llvm::Value *ExpectedVal, llvm::Value *DesiredVal, llvm::AtomicOrdering Success = llvm::AtomicOrdering::SequentiallyConsistent, llvm::AtomicOrdering Failure = llvm::AtomicOrdering::SequentiallyConsistent, bool IsWeak = false); /// Emit atomic update as libcalls. void EmitAtomicUpdateLibcall(llvm::AtomicOrdering AO, const llvm::function_ref &UpdateOp, bool IsVolatile); /// Emit atomic update as LLVM instructions. void EmitAtomicUpdateOp(llvm::AtomicOrdering AO, const llvm::function_ref &UpdateOp, bool IsVolatile); /// Emit atomic update as libcalls. void EmitAtomicUpdateLibcall(llvm::AtomicOrdering AO, RValue UpdateRVal, bool IsVolatile); /// Emit atomic update as LLVM instructions. void EmitAtomicUpdateOp(llvm::AtomicOrdering AO, RValue UpdateRal, bool IsVolatile); }; } Address AtomicInfo::CreateTempAlloca() const { Address TempAlloca = CGF.CreateMemTemp( (LVal.isBitField() && ValueSizeInBits > AtomicSizeInBits) ? ValueTy : AtomicTy, getAtomicAlignment(), "atomic-temp"); // Cast to pointer to value type for bitfields. if (LVal.isBitField()) return CGF.Builder.CreatePointerBitCastOrAddrSpaceCast( TempAlloca, getAtomicAddress().getType()); return TempAlloca; } static RValue emitAtomicLibcall(CodeGenFunction &CGF, StringRef fnName, QualType resultType, CallArgList &args) { const CGFunctionInfo &fnInfo = CGF.CGM.getTypes().arrangeBuiltinFunctionCall(resultType, args); llvm::FunctionType *fnTy = CGF.CGM.getTypes().GetFunctionType(fnInfo); llvm::AttrBuilder fnAttrB; fnAttrB.addAttribute(llvm::Attribute::NoUnwind); fnAttrB.addAttribute(llvm::Attribute::WillReturn); llvm::AttributeList fnAttrs = llvm::AttributeList::get( CGF.getLLVMContext(), llvm::AttributeList::FunctionIndex, fnAttrB); llvm::FunctionCallee fn = CGF.CGM.CreateRuntimeFunction(fnTy, fnName, fnAttrs); auto callee = CGCallee::forDirect(fn); return CGF.EmitCall(fnInfo, callee, ReturnValueSlot(), args); } /// Does a store of the given IR type modify the full expected width? static bool isFullSizeType(CodeGenModule &CGM, llvm::Type *type, uint64_t expectedSize) { return (CGM.getDataLayout().getTypeStoreSize(type) * 8 == expectedSize); } /// Does the atomic type require memsetting to zero before initialization? /// /// The IR type is provided as a way of making certain queries faster. bool AtomicInfo::requiresMemSetZero(llvm::Type *type) const { // If the atomic type has size padding, we definitely need a memset. if (hasPadding()) return true; // Otherwise, do some simple heuristics to try to avoid it: switch (getEvaluationKind()) { // For scalars and complexes, check whether the store size of the // type uses the full size. case TEK_Scalar: return !isFullSizeType(CGF.CGM, type, AtomicSizeInBits); case TEK_Complex: return !isFullSizeType(CGF.CGM, type->getStructElementType(0), AtomicSizeInBits / 2); // Padding in structs has an undefined bit pattern. User beware. case TEK_Aggregate: return false; } llvm_unreachable("bad evaluation kind"); } bool AtomicInfo::emitMemSetZeroIfNecessary() const { assert(LVal.isSimple()); llvm::Value *addr = LVal.getPointer(CGF); if (!requiresMemSetZero(addr->getType()->getPointerElementType())) return false; CGF.Builder.CreateMemSet( addr, llvm::ConstantInt::get(CGF.Int8Ty, 0), CGF.getContext().toCharUnitsFromBits(AtomicSizeInBits).getQuantity(), LVal.getAlignment().getAsAlign()); return true; } static void emitAtomicCmpXchg(CodeGenFunction &CGF, AtomicExpr *E, bool IsWeak, Address Dest, Address Ptr, Address Val1, Address Val2, uint64_t Size, llvm::AtomicOrdering SuccessOrder, llvm::AtomicOrdering FailureOrder, llvm::SyncScope::ID Scope) { // Note that cmpxchg doesn't support weak cmpxchg, at least at the moment. llvm::Value *Expected = CGF.Builder.CreateLoad(Val1); llvm::Value *Desired = CGF.Builder.CreateLoad(Val2); llvm::AtomicCmpXchgInst *Pair = CGF.Builder.CreateAtomicCmpXchg( Ptr.getPointer(), Expected, Desired, SuccessOrder, FailureOrder, Scope); Pair->setVolatile(E->isVolatile()); Pair->setWeak(IsWeak); // Cmp holds the result of the compare-exchange operation: true on success, // false on failure. llvm::Value *Old = CGF.Builder.CreateExtractValue(Pair, 0); llvm::Value *Cmp = CGF.Builder.CreateExtractValue(Pair, 1); // This basic block is used to hold the store instruction if the operation // failed. llvm::BasicBlock *StoreExpectedBB = CGF.createBasicBlock("cmpxchg.store_expected", CGF.CurFn); // This basic block is the exit point of the operation, we should end up // here regardless of whether or not the operation succeeded. llvm::BasicBlock *ContinueBB = CGF.createBasicBlock("cmpxchg.continue", CGF.CurFn); // Update Expected if Expected isn't equal to Old, otherwise branch to the // exit point. CGF.Builder.CreateCondBr(Cmp, ContinueBB, StoreExpectedBB); CGF.Builder.SetInsertPoint(StoreExpectedBB); // Update the memory at Expected with Old's value. CGF.Builder.CreateStore(Old, Val1); // Finally, branch to the exit point. CGF.Builder.CreateBr(ContinueBB); CGF.Builder.SetInsertPoint(ContinueBB); // Update the memory at Dest with Cmp's value. CGF.EmitStoreOfScalar(Cmp, CGF.MakeAddrLValue(Dest, E->getType())); } /// Given an ordering required on success, emit all possible cmpxchg /// instructions to cope with the provided (but possibly only dynamically known) /// FailureOrder. static void emitAtomicCmpXchgFailureSet(CodeGenFunction &CGF, AtomicExpr *E, bool IsWeak, Address Dest, Address Ptr, Address Val1, Address Val2, llvm::Value *FailureOrderVal, uint64_t Size, llvm::AtomicOrdering SuccessOrder, llvm::SyncScope::ID Scope) { llvm::AtomicOrdering FailureOrder; if (llvm::ConstantInt *FO = dyn_cast(FailureOrderVal)) { auto FOS = FO->getSExtValue(); if (!llvm::isValidAtomicOrderingCABI(FOS)) FailureOrder = llvm::AtomicOrdering::Monotonic; else switch ((llvm::AtomicOrderingCABI)FOS) { case llvm::AtomicOrderingCABI::relaxed: // 31.7.2.18: "The failure argument shall not be memory_order_release // nor memory_order_acq_rel". Fallback to monotonic. case llvm::AtomicOrderingCABI::release: case llvm::AtomicOrderingCABI::acq_rel: FailureOrder = llvm::AtomicOrdering::Monotonic; break; case llvm::AtomicOrderingCABI::consume: case llvm::AtomicOrderingCABI::acquire: FailureOrder = llvm::AtomicOrdering::Acquire; break; case llvm::AtomicOrderingCABI::seq_cst: FailureOrder = llvm::AtomicOrdering::SequentiallyConsistent; break; } // Prior to c++17, "the failure argument shall be no stronger than the // success argument". This condition has been lifted and the only // precondition is 31.7.2.18. Effectively treat this as a DR and skip // language version checks. emitAtomicCmpXchg(CGF, E, IsWeak, Dest, Ptr, Val1, Val2, Size, SuccessOrder, FailureOrder, Scope); return; } // Create all the relevant BB's auto *MonotonicBB = CGF.createBasicBlock("monotonic_fail", CGF.CurFn); auto *AcquireBB = CGF.createBasicBlock("acquire_fail", CGF.CurFn); auto *SeqCstBB = CGF.createBasicBlock("seqcst_fail", CGF.CurFn); auto *ContBB = CGF.createBasicBlock("atomic.continue", CGF.CurFn); // MonotonicBB is arbitrarily chosen as the default case; in practice, this // doesn't matter unless someone is crazy enough to use something that // doesn't fold to a constant for the ordering. llvm::SwitchInst *SI = CGF.Builder.CreateSwitch(FailureOrderVal, MonotonicBB); // Implemented as acquire, since it's the closest in LLVM. SI->addCase(CGF.Builder.getInt32((int)llvm::AtomicOrderingCABI::consume), AcquireBB); SI->addCase(CGF.Builder.getInt32((int)llvm::AtomicOrderingCABI::acquire), AcquireBB); SI->addCase(CGF.Builder.getInt32((int)llvm::AtomicOrderingCABI::seq_cst), SeqCstBB); // Emit all the different atomics CGF.Builder.SetInsertPoint(MonotonicBB); emitAtomicCmpXchg(CGF, E, IsWeak, Dest, Ptr, Val1, Val2, Size, SuccessOrder, llvm::AtomicOrdering::Monotonic, Scope); CGF.Builder.CreateBr(ContBB); CGF.Builder.SetInsertPoint(AcquireBB); emitAtomicCmpXchg(CGF, E, IsWeak, Dest, Ptr, Val1, Val2, Size, SuccessOrder, llvm::AtomicOrdering::Acquire, Scope); CGF.Builder.CreateBr(ContBB); CGF.Builder.SetInsertPoint(SeqCstBB); emitAtomicCmpXchg(CGF, E, IsWeak, Dest, Ptr, Val1, Val2, Size, SuccessOrder, llvm::AtomicOrdering::SequentiallyConsistent, Scope); CGF.Builder.CreateBr(ContBB); CGF.Builder.SetInsertPoint(ContBB); } /// Duplicate the atomic min/max operation in conventional IR for the builtin /// variants that return the new rather than the original value. static llvm::Value *EmitPostAtomicMinMax(CGBuilderTy &Builder, AtomicExpr::AtomicOp Op, bool IsSigned, llvm::Value *OldVal, llvm::Value *RHS) { llvm::CmpInst::Predicate Pred; switch (Op) { default: llvm_unreachable("Unexpected min/max operation"); case AtomicExpr::AO__atomic_max_fetch: Pred = IsSigned ? llvm::CmpInst::ICMP_SGT : llvm::CmpInst::ICMP_UGT; break; case AtomicExpr::AO__atomic_min_fetch: Pred = IsSigned ? llvm::CmpInst::ICMP_SLT : llvm::CmpInst::ICMP_ULT; break; } llvm::Value *Cmp = Builder.CreateICmp(Pred, OldVal, RHS, "tst"); return Builder.CreateSelect(Cmp, OldVal, RHS, "newval"); } static void EmitAtomicOp(CodeGenFunction &CGF, AtomicExpr *E, Address Dest, Address Ptr, Address Val1, Address Val2, llvm::Value *IsWeak, llvm::Value *FailureOrder, uint64_t Size, llvm::AtomicOrdering Order, llvm::SyncScope::ID Scope) { llvm::AtomicRMWInst::BinOp Op = llvm::AtomicRMWInst::Add; bool PostOpMinMax = false; unsigned PostOp = 0; switch (E->getOp()) { case AtomicExpr::AO__c11_atomic_init: case AtomicExpr::AO__opencl_atomic_init: llvm_unreachable("Already handled!"); case AtomicExpr::AO__c11_atomic_compare_exchange_strong: case AtomicExpr::AO__opencl_atomic_compare_exchange_strong: emitAtomicCmpXchgFailureSet(CGF, E, false, Dest, Ptr, Val1, Val2, FailureOrder, Size, Order, Scope); return; case AtomicExpr::AO__c11_atomic_compare_exchange_weak: case AtomicExpr::AO__opencl_atomic_compare_exchange_weak: emitAtomicCmpXchgFailureSet(CGF, E, true, Dest, Ptr, Val1, Val2, FailureOrder, Size, Order, Scope); return; case AtomicExpr::AO__atomic_compare_exchange: case AtomicExpr::AO__atomic_compare_exchange_n: { if (llvm::ConstantInt *IsWeakC = dyn_cast(IsWeak)) { emitAtomicCmpXchgFailureSet(CGF, E, IsWeakC->getZExtValue(), Dest, Ptr, Val1, Val2, FailureOrder, Size, Order, Scope); } else { // Create all the relevant BB's llvm::BasicBlock *StrongBB = CGF.createBasicBlock("cmpxchg.strong", CGF.CurFn); llvm::BasicBlock *WeakBB = CGF.createBasicBlock("cmxchg.weak", CGF.CurFn); llvm::BasicBlock *ContBB = CGF.createBasicBlock("cmpxchg.continue", CGF.CurFn); llvm::SwitchInst *SI = CGF.Builder.CreateSwitch(IsWeak, WeakBB); SI->addCase(CGF.Builder.getInt1(false), StrongBB); CGF.Builder.SetInsertPoint(StrongBB); emitAtomicCmpXchgFailureSet(CGF, E, false, Dest, Ptr, Val1, Val2, FailureOrder, Size, Order, Scope); CGF.Builder.CreateBr(ContBB); CGF.Builder.SetInsertPoint(WeakBB); emitAtomicCmpXchgFailureSet(CGF, E, true, Dest, Ptr, Val1, Val2, FailureOrder, Size, Order, Scope); CGF.Builder.CreateBr(ContBB); CGF.Builder.SetInsertPoint(ContBB); } return; } case AtomicExpr::AO__c11_atomic_load: case AtomicExpr::AO__opencl_atomic_load: case AtomicExpr::AO__atomic_load_n: case AtomicExpr::AO__atomic_load: { llvm::LoadInst *Load = CGF.Builder.CreateLoad(Ptr); Load->setAtomic(Order, Scope); Load->setVolatile(E->isVolatile()); CGF.Builder.CreateStore(Load, Dest); return; } case AtomicExpr::AO__c11_atomic_store: case AtomicExpr::AO__opencl_atomic_store: case AtomicExpr::AO__atomic_store: case AtomicExpr::AO__atomic_store_n: { llvm::Value *LoadVal1 = CGF.Builder.CreateLoad(Val1); llvm::StoreInst *Store = CGF.Builder.CreateStore(LoadVal1, Ptr); Store->setAtomic(Order, Scope); Store->setVolatile(E->isVolatile()); return; } case AtomicExpr::AO__c11_atomic_exchange: case AtomicExpr::AO__opencl_atomic_exchange: case AtomicExpr::AO__atomic_exchange_n: case AtomicExpr::AO__atomic_exchange: Op = llvm::AtomicRMWInst::Xchg; break; case AtomicExpr::AO__atomic_add_fetch: PostOp = E->getValueType()->isFloatingType() ? llvm::Instruction::FAdd : llvm::Instruction::Add; LLVM_FALLTHROUGH; case AtomicExpr::AO__c11_atomic_fetch_add: case AtomicExpr::AO__opencl_atomic_fetch_add: case AtomicExpr::AO__atomic_fetch_add: Op = E->getValueType()->isFloatingType() ? llvm::AtomicRMWInst::FAdd : llvm::AtomicRMWInst::Add; break; case AtomicExpr::AO__atomic_sub_fetch: PostOp = E->getValueType()->isFloatingType() ? llvm::Instruction::FSub : llvm::Instruction::Sub; LLVM_FALLTHROUGH; case AtomicExpr::AO__c11_atomic_fetch_sub: case AtomicExpr::AO__opencl_atomic_fetch_sub: case AtomicExpr::AO__atomic_fetch_sub: Op = E->getValueType()->isFloatingType() ? llvm::AtomicRMWInst::FSub : llvm::AtomicRMWInst::Sub; break; case AtomicExpr::AO__atomic_min_fetch: PostOpMinMax = true; LLVM_FALLTHROUGH; case AtomicExpr::AO__c11_atomic_fetch_min: case AtomicExpr::AO__opencl_atomic_fetch_min: case AtomicExpr::AO__atomic_fetch_min: Op = E->getValueType()->isSignedIntegerType() ? llvm::AtomicRMWInst::Min : llvm::AtomicRMWInst::UMin; break; case AtomicExpr::AO__atomic_max_fetch: PostOpMinMax = true; LLVM_FALLTHROUGH; case AtomicExpr::AO__c11_atomic_fetch_max: case AtomicExpr::AO__opencl_atomic_fetch_max: case AtomicExpr::AO__atomic_fetch_max: Op = E->getValueType()->isSignedIntegerType() ? llvm::AtomicRMWInst::Max : llvm::AtomicRMWInst::UMax; break; case AtomicExpr::AO__atomic_and_fetch: PostOp = llvm::Instruction::And; LLVM_FALLTHROUGH; case AtomicExpr::AO__c11_atomic_fetch_and: case AtomicExpr::AO__opencl_atomic_fetch_and: case AtomicExpr::AO__atomic_fetch_and: Op = llvm::AtomicRMWInst::And; break; case AtomicExpr::AO__atomic_or_fetch: PostOp = llvm::Instruction::Or; LLVM_FALLTHROUGH; case AtomicExpr::AO__c11_atomic_fetch_or: case AtomicExpr::AO__opencl_atomic_fetch_or: case AtomicExpr::AO__atomic_fetch_or: Op = llvm::AtomicRMWInst::Or; break; case AtomicExpr::AO__atomic_xor_fetch: PostOp = llvm::Instruction::Xor; LLVM_FALLTHROUGH; case AtomicExpr::AO__c11_atomic_fetch_xor: case AtomicExpr::AO__opencl_atomic_fetch_xor: case AtomicExpr::AO__atomic_fetch_xor: Op = llvm::AtomicRMWInst::Xor; break; case AtomicExpr::AO__atomic_nand_fetch: PostOp = llvm::Instruction::And; // the NOT is special cased below LLVM_FALLTHROUGH; case AtomicExpr::AO__atomic_fetch_nand: Op = llvm::AtomicRMWInst::Nand; break; } llvm::Value *LoadVal1 = CGF.Builder.CreateLoad(Val1); llvm::AtomicRMWInst *RMWI = CGF.Builder.CreateAtomicRMW(Op, Ptr.getPointer(), LoadVal1, Order, Scope); RMWI->setVolatile(E->isVolatile()); // For __atomic_*_fetch operations, perform the operation again to // determine the value which was written. llvm::Value *Result = RMWI; if (PostOpMinMax) Result = EmitPostAtomicMinMax(CGF.Builder, E->getOp(), E->getValueType()->isSignedIntegerType(), RMWI, LoadVal1); else if (PostOp) Result = CGF.Builder.CreateBinOp((llvm::Instruction::BinaryOps)PostOp, RMWI, LoadVal1); if (E->getOp() == AtomicExpr::AO__atomic_nand_fetch) Result = CGF.Builder.CreateNot(Result); CGF.Builder.CreateStore(Result, Dest); } // This function emits any expression (scalar, complex, or aggregate) // into a temporary alloca. static Address EmitValToTemp(CodeGenFunction &CGF, Expr *E) { Address DeclPtr = CGF.CreateMemTemp(E->getType(), ".atomictmp"); CGF.EmitAnyExprToMem(E, DeclPtr, E->getType().getQualifiers(), /*Init*/ true); return DeclPtr; } static void EmitAtomicOp(CodeGenFunction &CGF, AtomicExpr *Expr, Address Dest, Address Ptr, Address Val1, Address Val2, llvm::Value *IsWeak, llvm::Value *FailureOrder, uint64_t Size, llvm::AtomicOrdering Order, llvm::Value *Scope) { auto ScopeModel = Expr->getScopeModel(); // LLVM atomic instructions always have synch scope. If clang atomic // expression has no scope operand, use default LLVM synch scope. if (!ScopeModel) { EmitAtomicOp(CGF, Expr, Dest, Ptr, Val1, Val2, IsWeak, FailureOrder, Size, Order, CGF.CGM.getLLVMContext().getOrInsertSyncScopeID("")); return; } // Handle constant scope. if (auto SC = dyn_cast(Scope)) { auto SCID = CGF.getTargetHooks().getLLVMSyncScopeID( CGF.CGM.getLangOpts(), ScopeModel->map(SC->getZExtValue()), Order, CGF.CGM.getLLVMContext()); EmitAtomicOp(CGF, Expr, Dest, Ptr, Val1, Val2, IsWeak, FailureOrder, Size, Order, SCID); return; } // Handle non-constant scope. auto &Builder = CGF.Builder; auto Scopes = ScopeModel->getRuntimeValues(); llvm::DenseMap BB; for (auto S : Scopes) BB[S] = CGF.createBasicBlock(getAsString(ScopeModel->map(S)), CGF.CurFn); llvm::BasicBlock *ContBB = CGF.createBasicBlock("atomic.scope.continue", CGF.CurFn); auto *SC = Builder.CreateIntCast(Scope, Builder.getInt32Ty(), false); // If unsupported synch scope is encountered at run time, assume a fallback // synch scope value. auto FallBack = ScopeModel->getFallBackValue(); llvm::SwitchInst *SI = Builder.CreateSwitch(SC, BB[FallBack]); for (auto S : Scopes) { auto *B = BB[S]; if (S != FallBack) SI->addCase(Builder.getInt32(S), B); Builder.SetInsertPoint(B); EmitAtomicOp(CGF, Expr, Dest, Ptr, Val1, Val2, IsWeak, FailureOrder, Size, Order, CGF.getTargetHooks().getLLVMSyncScopeID(CGF.CGM.getLangOpts(), ScopeModel->map(S), Order, CGF.getLLVMContext())); Builder.CreateBr(ContBB); } Builder.SetInsertPoint(ContBB); } static void AddDirectArgument(CodeGenFunction &CGF, CallArgList &Args, bool UseOptimizedLibcall, llvm::Value *Val, QualType ValTy, SourceLocation Loc, CharUnits SizeInChars) { if (UseOptimizedLibcall) { // Load value and pass it to the function directly. CharUnits Align = CGF.getContext().getTypeAlignInChars(ValTy); int64_t SizeInBits = CGF.getContext().toBits(SizeInChars); ValTy = CGF.getContext().getIntTypeForBitwidth(SizeInBits, /*Signed=*/false); llvm::Type *IPtrTy = llvm::IntegerType::get(CGF.getLLVMContext(), SizeInBits)->getPointerTo(); Address Ptr = Address(CGF.Builder.CreateBitCast(Val, IPtrTy), Align); Val = CGF.EmitLoadOfScalar(Ptr, false, CGF.getContext().getPointerType(ValTy), Loc); // Coerce the value into an appropriately sized integer type. Args.add(RValue::get(Val), ValTy); } else { // Non-optimized functions always take a reference. Args.add(RValue::get(CGF.EmitCastToVoidPtr(Val)), CGF.getContext().VoidPtrTy); } } RValue CodeGenFunction::EmitAtomicExpr(AtomicExpr *E) { QualType AtomicTy = E->getPtr()->getType()->getPointeeType(); QualType MemTy = AtomicTy; if (const AtomicType *AT = AtomicTy->getAs()) MemTy = AT->getValueType(); llvm::Value *IsWeak = nullptr, *OrderFail = nullptr; Address Val1 = Address::invalid(); Address Val2 = Address::invalid(); Address Dest = Address::invalid(); Address Ptr = EmitPointerWithAlignment(E->getPtr()); if (E->getOp() == AtomicExpr::AO__c11_atomic_init || E->getOp() == AtomicExpr::AO__opencl_atomic_init) { LValue lvalue = MakeAddrLValue(Ptr, AtomicTy); EmitAtomicInit(E->getVal1(), lvalue); return RValue::get(nullptr); } auto TInfo = getContext().getTypeInfoInChars(AtomicTy); uint64_t Size = TInfo.Width.getQuantity(); unsigned MaxInlineWidthInBits = getTarget().getMaxAtomicInlineWidth(); bool Oversized = getContext().toBits(TInfo.Width) > MaxInlineWidthInBits; bool Misaligned = (Ptr.getAlignment() % TInfo.Width) != 0; bool UseLibcall = Misaligned | Oversized; bool ShouldCastToIntPtrTy = true; CharUnits MaxInlineWidth = getContext().toCharUnitsFromBits(MaxInlineWidthInBits); DiagnosticsEngine &Diags = CGM.getDiags(); if (Misaligned) { Diags.Report(E->getBeginLoc(), diag::warn_atomic_op_misaligned) << (int)TInfo.Width.getQuantity() << (int)Ptr.getAlignment().getQuantity(); } if (Oversized) { Diags.Report(E->getBeginLoc(), diag::warn_atomic_op_oversized) << (int)TInfo.Width.getQuantity() << (int)MaxInlineWidth.getQuantity(); } llvm::Value *Order = EmitScalarExpr(E->getOrder()); llvm::Value *Scope = E->getScopeModel() ? EmitScalarExpr(E->getScope()) : nullptr; switch (E->getOp()) { case AtomicExpr::AO__c11_atomic_init: case AtomicExpr::AO__opencl_atomic_init: llvm_unreachable("Already handled above with EmitAtomicInit!"); case AtomicExpr::AO__c11_atomic_load: case AtomicExpr::AO__opencl_atomic_load: case AtomicExpr::AO__atomic_load_n: break; case AtomicExpr::AO__atomic_load: Dest = EmitPointerWithAlignment(E->getVal1()); break; case AtomicExpr::AO__atomic_store: Val1 = EmitPointerWithAlignment(E->getVal1()); break; case AtomicExpr::AO__atomic_exchange: Val1 = EmitPointerWithAlignment(E->getVal1()); Dest = EmitPointerWithAlignment(E->getVal2()); break; case AtomicExpr::AO__c11_atomic_compare_exchange_strong: case AtomicExpr::AO__c11_atomic_compare_exchange_weak: case AtomicExpr::AO__opencl_atomic_compare_exchange_strong: case AtomicExpr::AO__opencl_atomic_compare_exchange_weak: case AtomicExpr::AO__atomic_compare_exchange_n: case AtomicExpr::AO__atomic_compare_exchange: Val1 = EmitPointerWithAlignment(E->getVal1()); if (E->getOp() == AtomicExpr::AO__atomic_compare_exchange) Val2 = EmitPointerWithAlignment(E->getVal2()); else Val2 = EmitValToTemp(*this, E->getVal2()); OrderFail = EmitScalarExpr(E->getOrderFail()); if (E->getOp() == AtomicExpr::AO__atomic_compare_exchange_n || E->getOp() == AtomicExpr::AO__atomic_compare_exchange) IsWeak = EmitScalarExpr(E->getWeak()); break; case AtomicExpr::AO__c11_atomic_fetch_add: case AtomicExpr::AO__c11_atomic_fetch_sub: case AtomicExpr::AO__opencl_atomic_fetch_add: case AtomicExpr::AO__opencl_atomic_fetch_sub: if (MemTy->isPointerType()) { // For pointer arithmetic, we're required to do a bit of math: // adding 1 to an int* is not the same as adding 1 to a uintptr_t. // ... but only for the C11 builtins. The GNU builtins expect the // user to multiply by sizeof(T). QualType Val1Ty = E->getVal1()->getType(); llvm::Value *Val1Scalar = EmitScalarExpr(E->getVal1()); CharUnits PointeeIncAmt = getContext().getTypeSizeInChars(MemTy->getPointeeType()); Val1Scalar = Builder.CreateMul(Val1Scalar, CGM.getSize(PointeeIncAmt)); auto Temp = CreateMemTemp(Val1Ty, ".atomictmp"); Val1 = Temp; EmitStoreOfScalar(Val1Scalar, MakeAddrLValue(Temp, Val1Ty)); break; } LLVM_FALLTHROUGH; case AtomicExpr::AO__atomic_fetch_add: case AtomicExpr::AO__atomic_fetch_sub: case AtomicExpr::AO__atomic_add_fetch: case AtomicExpr::AO__atomic_sub_fetch: ShouldCastToIntPtrTy = !MemTy->isFloatingType(); LLVM_FALLTHROUGH; case AtomicExpr::AO__c11_atomic_store: case AtomicExpr::AO__c11_atomic_exchange: case AtomicExpr::AO__opencl_atomic_store: case AtomicExpr::AO__opencl_atomic_exchange: case AtomicExpr::AO__atomic_store_n: case AtomicExpr::AO__atomic_exchange_n: case AtomicExpr::AO__c11_atomic_fetch_and: case AtomicExpr::AO__c11_atomic_fetch_or: case AtomicExpr::AO__c11_atomic_fetch_xor: case AtomicExpr::AO__c11_atomic_fetch_max: case AtomicExpr::AO__c11_atomic_fetch_min: case AtomicExpr::AO__opencl_atomic_fetch_and: case AtomicExpr::AO__opencl_atomic_fetch_or: case AtomicExpr::AO__opencl_atomic_fetch_xor: case AtomicExpr::AO__opencl_atomic_fetch_min: case AtomicExpr::AO__opencl_atomic_fetch_max: case AtomicExpr::AO__atomic_fetch_and: case AtomicExpr::AO__atomic_fetch_or: case AtomicExpr::AO__atomic_fetch_xor: case AtomicExpr::AO__atomic_fetch_nand: case AtomicExpr::AO__atomic_and_fetch: case AtomicExpr::AO__atomic_or_fetch: case AtomicExpr::AO__atomic_xor_fetch: case AtomicExpr::AO__atomic_nand_fetch: case AtomicExpr::AO__atomic_max_fetch: case AtomicExpr::AO__atomic_min_fetch: case AtomicExpr::AO__atomic_fetch_max: case AtomicExpr::AO__atomic_fetch_min: Val1 = EmitValToTemp(*this, E->getVal1()); break; } QualType RValTy = E->getType().getUnqualifiedType(); // The inlined atomics only function on iN types, where N is a power of 2. We // need to make sure (via temporaries if necessary) that all incoming values // are compatible. LValue AtomicVal = MakeAddrLValue(Ptr, AtomicTy); AtomicInfo Atomics(*this, AtomicVal); if (ShouldCastToIntPtrTy) { Ptr = Atomics.emitCastToAtomicIntPointer(Ptr); if (Val1.isValid()) Val1 = Atomics.convertToAtomicIntPointer(Val1); if (Val2.isValid()) Val2 = Atomics.convertToAtomicIntPointer(Val2); } if (Dest.isValid()) { if (ShouldCastToIntPtrTy) Dest = Atomics.emitCastToAtomicIntPointer(Dest); } else if (E->isCmpXChg()) Dest = CreateMemTemp(RValTy, "cmpxchg.bool"); else if (!RValTy->isVoidType()) { Dest = Atomics.CreateTempAlloca(); if (ShouldCastToIntPtrTy) Dest = Atomics.emitCastToAtomicIntPointer(Dest); } // Use a library call. See: http://gcc.gnu.org/wiki/Atomic/GCCMM/LIbrary . if (UseLibcall) { bool UseOptimizedLibcall = false; switch (E->getOp()) { case AtomicExpr::AO__c11_atomic_init: case AtomicExpr::AO__opencl_atomic_init: llvm_unreachable("Already handled above with EmitAtomicInit!"); case AtomicExpr::AO__c11_atomic_fetch_add: case AtomicExpr::AO__opencl_atomic_fetch_add: case AtomicExpr::AO__atomic_fetch_add: case AtomicExpr::AO__c11_atomic_fetch_and: case AtomicExpr::AO__opencl_atomic_fetch_and: case AtomicExpr::AO__atomic_fetch_and: case AtomicExpr::AO__c11_atomic_fetch_or: case AtomicExpr::AO__opencl_atomic_fetch_or: case AtomicExpr::AO__atomic_fetch_or: case AtomicExpr::AO__atomic_fetch_nand: case AtomicExpr::AO__c11_atomic_fetch_sub: case AtomicExpr::AO__opencl_atomic_fetch_sub: case AtomicExpr::AO__atomic_fetch_sub: case AtomicExpr::AO__c11_atomic_fetch_xor: case AtomicExpr::AO__opencl_atomic_fetch_xor: case AtomicExpr::AO__opencl_atomic_fetch_min: case AtomicExpr::AO__opencl_atomic_fetch_max: case AtomicExpr::AO__atomic_fetch_xor: case AtomicExpr::AO__c11_atomic_fetch_max: case AtomicExpr::AO__c11_atomic_fetch_min: case AtomicExpr::AO__atomic_add_fetch: case AtomicExpr::AO__atomic_and_fetch: case AtomicExpr::AO__atomic_nand_fetch: case AtomicExpr::AO__atomic_or_fetch: case AtomicExpr::AO__atomic_sub_fetch: case AtomicExpr::AO__atomic_xor_fetch: case AtomicExpr::AO__atomic_fetch_max: case AtomicExpr::AO__atomic_fetch_min: case AtomicExpr::AO__atomic_max_fetch: case AtomicExpr::AO__atomic_min_fetch: // For these, only library calls for certain sizes exist. UseOptimizedLibcall = true; break; case AtomicExpr::AO__atomic_load: case AtomicExpr::AO__atomic_store: case AtomicExpr::AO__atomic_exchange: case AtomicExpr::AO__atomic_compare_exchange: // Use the generic version if we don't know that the operand will be // suitably aligned for the optimized version. if (Misaligned) break; LLVM_FALLTHROUGH; case AtomicExpr::AO__c11_atomic_load: case AtomicExpr::AO__c11_atomic_store: case AtomicExpr::AO__c11_atomic_exchange: case AtomicExpr::AO__c11_atomic_compare_exchange_weak: case AtomicExpr::AO__c11_atomic_compare_exchange_strong: case AtomicExpr::AO__opencl_atomic_load: case AtomicExpr::AO__opencl_atomic_store: case AtomicExpr::AO__opencl_atomic_exchange: case AtomicExpr::AO__opencl_atomic_compare_exchange_weak: case AtomicExpr::AO__opencl_atomic_compare_exchange_strong: case AtomicExpr::AO__atomic_load_n: case AtomicExpr::AO__atomic_store_n: case AtomicExpr::AO__atomic_exchange_n: case AtomicExpr::AO__atomic_compare_exchange_n: // Only use optimized library calls for sizes for which they exist. // FIXME: Size == 16 optimized library functions exist too. if (Size == 1 || Size == 2 || Size == 4 || Size == 8) UseOptimizedLibcall = true; break; } CallArgList Args; if (!UseOptimizedLibcall) { // For non-optimized library calls, the size is the first parameter Args.add(RValue::get(llvm::ConstantInt::get(SizeTy, Size)), getContext().getSizeType()); } // Atomic address is the first or second parameter // The OpenCL atomic library functions only accept pointer arguments to // generic address space. auto CastToGenericAddrSpace = [&](llvm::Value *V, QualType PT) { if (!E->isOpenCL()) return V; auto AS = PT->castAs()->getPointeeType().getAddressSpace(); if (AS == LangAS::opencl_generic) return V; auto DestAS = getContext().getTargetAddressSpace(LangAS::opencl_generic); auto T = V->getType(); auto *DestType = T->getPointerElementType()->getPointerTo(DestAS); return getTargetHooks().performAddrSpaceCast( *this, V, AS, LangAS::opencl_generic, DestType, false); }; Args.add(RValue::get(CastToGenericAddrSpace( EmitCastToVoidPtr(Ptr.getPointer()), E->getPtr()->getType())), getContext().VoidPtrTy); std::string LibCallName; QualType LoweredMemTy = MemTy->isPointerType() ? getContext().getIntPtrType() : MemTy; QualType RetTy; bool HaveRetTy = false; llvm::Instruction::BinaryOps PostOp = (llvm::Instruction::BinaryOps)0; bool PostOpMinMax = false; switch (E->getOp()) { case AtomicExpr::AO__c11_atomic_init: case AtomicExpr::AO__opencl_atomic_init: llvm_unreachable("Already handled!"); // There is only one libcall for compare an exchange, because there is no // optimisation benefit possible from a libcall version of a weak compare // and exchange. // bool __atomic_compare_exchange(size_t size, void *mem, void *expected, // void *desired, int success, int failure) // bool __atomic_compare_exchange_N(T *mem, T *expected, T desired, // int success, int failure) case AtomicExpr::AO__c11_atomic_compare_exchange_weak: case AtomicExpr::AO__c11_atomic_compare_exchange_strong: case AtomicExpr::AO__opencl_atomic_compare_exchange_weak: case AtomicExpr::AO__opencl_atomic_compare_exchange_strong: case AtomicExpr::AO__atomic_compare_exchange: case AtomicExpr::AO__atomic_compare_exchange_n: LibCallName = "__atomic_compare_exchange"; RetTy = getContext().BoolTy; HaveRetTy = true; Args.add( RValue::get(CastToGenericAddrSpace( EmitCastToVoidPtr(Val1.getPointer()), E->getVal1()->getType())), getContext().VoidPtrTy); AddDirectArgument(*this, Args, UseOptimizedLibcall, Val2.getPointer(), MemTy, E->getExprLoc(), TInfo.Width); Args.add(RValue::get(Order), getContext().IntTy); Order = OrderFail; break; // void __atomic_exchange(size_t size, void *mem, void *val, void *return, // int order) // T __atomic_exchange_N(T *mem, T val, int order) case AtomicExpr::AO__c11_atomic_exchange: case AtomicExpr::AO__opencl_atomic_exchange: case AtomicExpr::AO__atomic_exchange_n: case AtomicExpr::AO__atomic_exchange: LibCallName = "__atomic_exchange"; AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), MemTy, E->getExprLoc(), TInfo.Width); break; // void __atomic_store(size_t size, void *mem, void *val, int order) // void __atomic_store_N(T *mem, T val, int order) case AtomicExpr::AO__c11_atomic_store: case AtomicExpr::AO__opencl_atomic_store: case AtomicExpr::AO__atomic_store: case AtomicExpr::AO__atomic_store_n: LibCallName = "__atomic_store"; RetTy = getContext().VoidTy; HaveRetTy = true; AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), MemTy, E->getExprLoc(), TInfo.Width); break; // void __atomic_load(size_t size, void *mem, void *return, int order) // T __atomic_load_N(T *mem, int order) case AtomicExpr::AO__c11_atomic_load: case AtomicExpr::AO__opencl_atomic_load: case AtomicExpr::AO__atomic_load: case AtomicExpr::AO__atomic_load_n: LibCallName = "__atomic_load"; break; // T __atomic_add_fetch_N(T *mem, T val, int order) // T __atomic_fetch_add_N(T *mem, T val, int order) case AtomicExpr::AO__atomic_add_fetch: PostOp = llvm::Instruction::Add; LLVM_FALLTHROUGH; case AtomicExpr::AO__c11_atomic_fetch_add: case AtomicExpr::AO__opencl_atomic_fetch_add: case AtomicExpr::AO__atomic_fetch_add: LibCallName = "__atomic_fetch_add"; AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), LoweredMemTy, E->getExprLoc(), TInfo.Width); break; // T __atomic_and_fetch_N(T *mem, T val, int order) // T __atomic_fetch_and_N(T *mem, T val, int order) case AtomicExpr::AO__atomic_and_fetch: PostOp = llvm::Instruction::And; LLVM_FALLTHROUGH; case AtomicExpr::AO__c11_atomic_fetch_and: case AtomicExpr::AO__opencl_atomic_fetch_and: case AtomicExpr::AO__atomic_fetch_and: LibCallName = "__atomic_fetch_and"; AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), MemTy, E->getExprLoc(), TInfo.Width); break; // T __atomic_or_fetch_N(T *mem, T val, int order) // T __atomic_fetch_or_N(T *mem, T val, int order) case AtomicExpr::AO__atomic_or_fetch: PostOp = llvm::Instruction::Or; LLVM_FALLTHROUGH; case AtomicExpr::AO__c11_atomic_fetch_or: case AtomicExpr::AO__opencl_atomic_fetch_or: case AtomicExpr::AO__atomic_fetch_or: LibCallName = "__atomic_fetch_or"; AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), MemTy, E->getExprLoc(), TInfo.Width); break; // T __atomic_sub_fetch_N(T *mem, T val, int order) // T __atomic_fetch_sub_N(T *mem, T val, int order) case AtomicExpr::AO__atomic_sub_fetch: PostOp = llvm::Instruction::Sub; LLVM_FALLTHROUGH; case AtomicExpr::AO__c11_atomic_fetch_sub: case AtomicExpr::AO__opencl_atomic_fetch_sub: case AtomicExpr::AO__atomic_fetch_sub: LibCallName = "__atomic_fetch_sub"; AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), LoweredMemTy, E->getExprLoc(), TInfo.Width); break; // T __atomic_xor_fetch_N(T *mem, T val, int order) // T __atomic_fetch_xor_N(T *mem, T val, int order) case AtomicExpr::AO__atomic_xor_fetch: PostOp = llvm::Instruction::Xor; LLVM_FALLTHROUGH; case AtomicExpr::AO__c11_atomic_fetch_xor: case AtomicExpr::AO__opencl_atomic_fetch_xor: case AtomicExpr::AO__atomic_fetch_xor: LibCallName = "__atomic_fetch_xor"; AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), MemTy, E->getExprLoc(), TInfo.Width); break; case AtomicExpr::AO__atomic_min_fetch: PostOpMinMax = true; LLVM_FALLTHROUGH; case AtomicExpr::AO__c11_atomic_fetch_min: case AtomicExpr::AO__atomic_fetch_min: case AtomicExpr::AO__opencl_atomic_fetch_min: LibCallName = E->getValueType()->isSignedIntegerType() ? "__atomic_fetch_min" : "__atomic_fetch_umin"; AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), LoweredMemTy, E->getExprLoc(), TInfo.Width); break; case AtomicExpr::AO__atomic_max_fetch: PostOpMinMax = true; LLVM_FALLTHROUGH; case AtomicExpr::AO__c11_atomic_fetch_max: case AtomicExpr::AO__atomic_fetch_max: case AtomicExpr::AO__opencl_atomic_fetch_max: LibCallName = E->getValueType()->isSignedIntegerType() ? "__atomic_fetch_max" : "__atomic_fetch_umax"; AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), LoweredMemTy, E->getExprLoc(), TInfo.Width); break; // T __atomic_nand_fetch_N(T *mem, T val, int order) // T __atomic_fetch_nand_N(T *mem, T val, int order) case AtomicExpr::AO__atomic_nand_fetch: PostOp = llvm::Instruction::And; // the NOT is special cased below LLVM_FALLTHROUGH; case AtomicExpr::AO__atomic_fetch_nand: LibCallName = "__atomic_fetch_nand"; AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), MemTy, E->getExprLoc(), TInfo.Width); break; } if (E->isOpenCL()) { LibCallName = std::string("__opencl") + StringRef(LibCallName).drop_front(1).str(); } // Optimized functions have the size in their name. if (UseOptimizedLibcall) LibCallName += "_" + llvm::utostr(Size); // By default, assume we return a value of the atomic type. if (!HaveRetTy) { if (UseOptimizedLibcall) { // Value is returned directly. // The function returns an appropriately sized integer type. RetTy = getContext().getIntTypeForBitwidth( getContext().toBits(TInfo.Width), /*Signed=*/false); } else { // Value is returned through parameter before the order. RetTy = getContext().VoidTy; Args.add(RValue::get(EmitCastToVoidPtr(Dest.getPointer())), getContext().VoidPtrTy); } } // order is always the last parameter Args.add(RValue::get(Order), getContext().IntTy); if (E->isOpenCL()) Args.add(RValue::get(Scope), getContext().IntTy); // PostOp is only needed for the atomic_*_fetch operations, and // thus is only needed for and implemented in the // UseOptimizedLibcall codepath. assert(UseOptimizedLibcall || (!PostOp && !PostOpMinMax)); RValue Res = emitAtomicLibcall(*this, LibCallName, RetTy, Args); // The value is returned directly from the libcall. if (E->isCmpXChg()) return Res; // The value is returned directly for optimized libcalls but the expr // provided an out-param. if (UseOptimizedLibcall && Res.getScalarVal()) { llvm::Value *ResVal = Res.getScalarVal(); if (PostOpMinMax) { llvm::Value *LoadVal1 = Args[1].getRValue(*this).getScalarVal(); ResVal = EmitPostAtomicMinMax(Builder, E->getOp(), E->getValueType()->isSignedIntegerType(), ResVal, LoadVal1); } else if (PostOp) { llvm::Value *LoadVal1 = Args[1].getRValue(*this).getScalarVal(); ResVal = Builder.CreateBinOp(PostOp, ResVal, LoadVal1); } if (E->getOp() == AtomicExpr::AO__atomic_nand_fetch) ResVal = Builder.CreateNot(ResVal); Builder.CreateStore( ResVal, Builder.CreateBitCast(Dest, ResVal->getType()->getPointerTo())); } if (RValTy->isVoidType()) return RValue::get(nullptr); return convertTempToRValue( Builder.CreateBitCast(Dest, ConvertTypeForMem(RValTy)->getPointerTo()), RValTy, E->getExprLoc()); } bool IsStore = E->getOp() == AtomicExpr::AO__c11_atomic_store || E->getOp() == AtomicExpr::AO__opencl_atomic_store || E->getOp() == AtomicExpr::AO__atomic_store || E->getOp() == AtomicExpr::AO__atomic_store_n; bool IsLoad = E->getOp() == AtomicExpr::AO__c11_atomic_load || E->getOp() == AtomicExpr::AO__opencl_atomic_load || E->getOp() == AtomicExpr::AO__atomic_load || E->getOp() == AtomicExpr::AO__atomic_load_n; if (isa(Order)) { auto ord = cast(Order)->getZExtValue(); // We should not ever get to a case where the ordering isn't a valid C ABI // value, but it's hard to enforce that in general. if (llvm::isValidAtomicOrderingCABI(ord)) switch ((llvm::AtomicOrderingCABI)ord) { case llvm::AtomicOrderingCABI::relaxed: EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, llvm::AtomicOrdering::Monotonic, Scope); break; case llvm::AtomicOrderingCABI::consume: case llvm::AtomicOrderingCABI::acquire: if (IsStore) break; // Avoid crashing on code with undefined behavior EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, llvm::AtomicOrdering::Acquire, Scope); break; case llvm::AtomicOrderingCABI::release: if (IsLoad) break; // Avoid crashing on code with undefined behavior EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, llvm::AtomicOrdering::Release, Scope); break; case llvm::AtomicOrderingCABI::acq_rel: if (IsLoad || IsStore) break; // Avoid crashing on code with undefined behavior EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, llvm::AtomicOrdering::AcquireRelease, Scope); break; case llvm::AtomicOrderingCABI::seq_cst: EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, llvm::AtomicOrdering::SequentiallyConsistent, Scope); break; } if (RValTy->isVoidType()) return RValue::get(nullptr); return convertTempToRValue( Builder.CreateBitCast(Dest, ConvertTypeForMem(RValTy)->getPointerTo( Dest.getAddressSpace())), RValTy, E->getExprLoc()); } // Long case, when Order isn't obviously constant. // Create all the relevant BB's llvm::BasicBlock *MonotonicBB = nullptr, *AcquireBB = nullptr, *ReleaseBB = nullptr, *AcqRelBB = nullptr, *SeqCstBB = nullptr; MonotonicBB = createBasicBlock("monotonic", CurFn); if (!IsStore) AcquireBB = createBasicBlock("acquire", CurFn); if (!IsLoad) ReleaseBB = createBasicBlock("release", CurFn); if (!IsLoad && !IsStore) AcqRelBB = createBasicBlock("acqrel", CurFn); SeqCstBB = createBasicBlock("seqcst", CurFn); llvm::BasicBlock *ContBB = createBasicBlock("atomic.continue", CurFn); // Create the switch for the split // MonotonicBB is arbitrarily chosen as the default case; in practice, this // doesn't matter unless someone is crazy enough to use something that // doesn't fold to a constant for the ordering. Order = Builder.CreateIntCast(Order, Builder.getInt32Ty(), false); llvm::SwitchInst *SI = Builder.CreateSwitch(Order, MonotonicBB); // Emit all the different atomics Builder.SetInsertPoint(MonotonicBB); EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, llvm::AtomicOrdering::Monotonic, Scope); Builder.CreateBr(ContBB); if (!IsStore) { Builder.SetInsertPoint(AcquireBB); EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, llvm::AtomicOrdering::Acquire, Scope); Builder.CreateBr(ContBB); SI->addCase(Builder.getInt32((int)llvm::AtomicOrderingCABI::consume), AcquireBB); SI->addCase(Builder.getInt32((int)llvm::AtomicOrderingCABI::acquire), AcquireBB); } if (!IsLoad) { Builder.SetInsertPoint(ReleaseBB); EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, llvm::AtomicOrdering::Release, Scope); Builder.CreateBr(ContBB); SI->addCase(Builder.getInt32((int)llvm::AtomicOrderingCABI::release), ReleaseBB); } if (!IsLoad && !IsStore) { Builder.SetInsertPoint(AcqRelBB); EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, llvm::AtomicOrdering::AcquireRelease, Scope); Builder.CreateBr(ContBB); SI->addCase(Builder.getInt32((int)llvm::AtomicOrderingCABI::acq_rel), AcqRelBB); } Builder.SetInsertPoint(SeqCstBB); EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, llvm::AtomicOrdering::SequentiallyConsistent, Scope); Builder.CreateBr(ContBB); SI->addCase(Builder.getInt32((int)llvm::AtomicOrderingCABI::seq_cst), SeqCstBB); // Cleanup and return Builder.SetInsertPoint(ContBB); if (RValTy->isVoidType()) return RValue::get(nullptr); assert(Atomics.getValueSizeInBits() <= Atomics.getAtomicSizeInBits()); return convertTempToRValue( Builder.CreateBitCast(Dest, ConvertTypeForMem(RValTy)->getPointerTo( Dest.getAddressSpace())), RValTy, E->getExprLoc()); } Address AtomicInfo::emitCastToAtomicIntPointer(Address addr) const { unsigned addrspace = cast(addr.getPointer()->getType())->getAddressSpace(); llvm::IntegerType *ty = llvm::IntegerType::get(CGF.getLLVMContext(), AtomicSizeInBits); return CGF.Builder.CreateBitCast(addr, ty->getPointerTo(addrspace)); } Address AtomicInfo::convertToAtomicIntPointer(Address Addr) const { llvm::Type *Ty = Addr.getElementType(); uint64_t SourceSizeInBits = CGF.CGM.getDataLayout().getTypeSizeInBits(Ty); if (SourceSizeInBits != AtomicSizeInBits) { Address Tmp = CreateTempAlloca(); CGF.Builder.CreateMemCpy(Tmp, Addr, std::min(AtomicSizeInBits, SourceSizeInBits) / 8); Addr = Tmp; } return emitCastToAtomicIntPointer(Addr); } RValue AtomicInfo::convertAtomicTempToRValue(Address addr, AggValueSlot resultSlot, SourceLocation loc, bool asValue) const { if (LVal.isSimple()) { if (EvaluationKind == TEK_Aggregate) return resultSlot.asRValue(); // Drill into the padding structure if we have one. if (hasPadding()) addr = CGF.Builder.CreateStructGEP(addr, 0); // Otherwise, just convert the temporary to an r-value using the // normal conversion routine. return CGF.convertTempToRValue(addr, getValueType(), loc); } if (!asValue) // Get RValue from temp memory as atomic for non-simple lvalues return RValue::get(CGF.Builder.CreateLoad(addr)); if (LVal.isBitField()) return CGF.EmitLoadOfBitfieldLValue( LValue::MakeBitfield(addr, LVal.getBitFieldInfo(), LVal.getType(), LVal.getBaseInfo(), TBAAAccessInfo()), loc); if (LVal.isVectorElt()) return CGF.EmitLoadOfLValue( LValue::MakeVectorElt(addr, LVal.getVectorIdx(), LVal.getType(), LVal.getBaseInfo(), TBAAAccessInfo()), loc); assert(LVal.isExtVectorElt()); return CGF.EmitLoadOfExtVectorElementLValue(LValue::MakeExtVectorElt( addr, LVal.getExtVectorElts(), LVal.getType(), LVal.getBaseInfo(), TBAAAccessInfo())); } RValue AtomicInfo::ConvertIntToValueOrAtomic(llvm::Value *IntVal, AggValueSlot ResultSlot, SourceLocation Loc, bool AsValue) const { // Try not to in some easy cases. assert(IntVal->getType()->isIntegerTy() && "Expected integer value"); if (getEvaluationKind() == TEK_Scalar && (((!LVal.isBitField() || LVal.getBitFieldInfo().Size == ValueSizeInBits) && !hasPadding()) || !AsValue)) { auto *ValTy = AsValue ? CGF.ConvertTypeForMem(ValueTy) : getAtomicAddress().getType()->getPointerElementType(); if (ValTy->isIntegerTy()) { assert(IntVal->getType() == ValTy && "Different integer types."); return RValue::get(CGF.EmitFromMemory(IntVal, ValueTy)); } else if (ValTy->isPointerTy()) return RValue::get(CGF.Builder.CreateIntToPtr(IntVal, ValTy)); else if (llvm::CastInst::isBitCastable(IntVal->getType(), ValTy)) return RValue::get(CGF.Builder.CreateBitCast(IntVal, ValTy)); } // Create a temporary. This needs to be big enough to hold the // atomic integer. Address Temp = Address::invalid(); bool TempIsVolatile = false; if (AsValue && getEvaluationKind() == TEK_Aggregate) { assert(!ResultSlot.isIgnored()); Temp = ResultSlot.getAddress(); TempIsVolatile = ResultSlot.isVolatile(); } else { Temp = CreateTempAlloca(); } // Slam the integer into the temporary. Address CastTemp = emitCastToAtomicIntPointer(Temp); CGF.Builder.CreateStore(IntVal, CastTemp) ->setVolatile(TempIsVolatile); return convertAtomicTempToRValue(Temp, ResultSlot, Loc, AsValue); } void AtomicInfo::EmitAtomicLoadLibcall(llvm::Value *AddForLoaded, llvm::AtomicOrdering AO, bool) { // void __atomic_load(size_t size, void *mem, void *return, int order); CallArgList Args; Args.add(RValue::get(getAtomicSizeValue()), CGF.getContext().getSizeType()); Args.add(RValue::get(CGF.EmitCastToVoidPtr(getAtomicPointer())), CGF.getContext().VoidPtrTy); Args.add(RValue::get(CGF.EmitCastToVoidPtr(AddForLoaded)), CGF.getContext().VoidPtrTy); Args.add( RValue::get(llvm::ConstantInt::get(CGF.IntTy, (int)llvm::toCABI(AO))), CGF.getContext().IntTy); emitAtomicLibcall(CGF, "__atomic_load", CGF.getContext().VoidTy, Args); } llvm::Value *AtomicInfo::EmitAtomicLoadOp(llvm::AtomicOrdering AO, bool IsVolatile) { // Okay, we're doing this natively. Address Addr = getAtomicAddressAsAtomicIntPointer(); llvm::LoadInst *Load = CGF.Builder.CreateLoad(Addr, "atomic-load"); Load->setAtomic(AO); // Other decoration. if (IsVolatile) Load->setVolatile(true); CGF.CGM.DecorateInstructionWithTBAA(Load, LVal.getTBAAInfo()); return Load; } /// An LValue is a candidate for having its loads and stores be made atomic if /// we are operating under /volatile:ms *and* the LValue itself is volatile and /// performing such an operation can be performed without a libcall. bool CodeGenFunction::LValueIsSuitableForInlineAtomic(LValue LV) { if (!CGM.getCodeGenOpts().MSVolatile) return false; AtomicInfo AI(*this, LV); bool IsVolatile = LV.isVolatile() || hasVolatileMember(LV.getType()); // An atomic is inline if we don't need to use a libcall. bool AtomicIsInline = !AI.shouldUseLibcall(); // MSVC doesn't seem to do this for types wider than a pointer. if (getContext().getTypeSize(LV.getType()) > getContext().getTypeSize(getContext().getIntPtrType())) return false; return IsVolatile && AtomicIsInline; } RValue CodeGenFunction::EmitAtomicLoad(LValue LV, SourceLocation SL, AggValueSlot Slot) { llvm::AtomicOrdering AO; bool IsVolatile = LV.isVolatileQualified(); if (LV.getType()->isAtomicType()) { AO = llvm::AtomicOrdering::SequentiallyConsistent; } else { AO = llvm::AtomicOrdering::Acquire; IsVolatile = true; } return EmitAtomicLoad(LV, SL, AO, IsVolatile, Slot); } RValue AtomicInfo::EmitAtomicLoad(AggValueSlot ResultSlot, SourceLocation Loc, bool AsValue, llvm::AtomicOrdering AO, bool IsVolatile) { // Check whether we should use a library call. if (shouldUseLibcall()) { Address TempAddr = Address::invalid(); if (LVal.isSimple() && !ResultSlot.isIgnored()) { assert(getEvaluationKind() == TEK_Aggregate); TempAddr = ResultSlot.getAddress(); } else TempAddr = CreateTempAlloca(); EmitAtomicLoadLibcall(TempAddr.getPointer(), AO, IsVolatile); // Okay, turn that back into the original value or whole atomic (for // non-simple lvalues) type. return convertAtomicTempToRValue(TempAddr, ResultSlot, Loc, AsValue); } // Okay, we're doing this natively. auto *Load = EmitAtomicLoadOp(AO, IsVolatile); // If we're ignoring an aggregate return, don't do anything. if (getEvaluationKind() == TEK_Aggregate && ResultSlot.isIgnored()) return RValue::getAggregate(Address::invalid(), false); // Okay, turn that back into the original value or atomic (for non-simple // lvalues) type. return ConvertIntToValueOrAtomic(Load, ResultSlot, Loc, AsValue); } /// Emit a load from an l-value of atomic type. Note that the r-value /// we produce is an r-value of the atomic *value* type. RValue CodeGenFunction::EmitAtomicLoad(LValue src, SourceLocation loc, llvm::AtomicOrdering AO, bool IsVolatile, AggValueSlot resultSlot) { AtomicInfo Atomics(*this, src); return Atomics.EmitAtomicLoad(resultSlot, loc, /*AsValue=*/true, AO, IsVolatile); } /// Copy an r-value into memory as part of storing to an atomic type. /// This needs to create a bit-pattern suitable for atomic operations. void AtomicInfo::emitCopyIntoMemory(RValue rvalue) const { assert(LVal.isSimple()); // If we have an r-value, the rvalue should be of the atomic type, // which means that the caller is responsible for having zeroed // any padding. Just do an aggregate copy of that type. if (rvalue.isAggregate()) { LValue Dest = CGF.MakeAddrLValue(getAtomicAddress(), getAtomicType()); LValue Src = CGF.MakeAddrLValue(rvalue.getAggregateAddress(), getAtomicType()); bool IsVolatile = rvalue.isVolatileQualified() || LVal.isVolatileQualified(); CGF.EmitAggregateCopy(Dest, Src, getAtomicType(), AggValueSlot::DoesNotOverlap, IsVolatile); return; } // Okay, otherwise we're copying stuff. // Zero out the buffer if necessary. emitMemSetZeroIfNecessary(); // Drill past the padding if present. LValue TempLVal = projectValue(); // Okay, store the rvalue in. if (rvalue.isScalar()) { CGF.EmitStoreOfScalar(rvalue.getScalarVal(), TempLVal, /*init*/ true); } else { CGF.EmitStoreOfComplex(rvalue.getComplexVal(), TempLVal, /*init*/ true); } } /// Materialize an r-value into memory for the purposes of storing it /// to an atomic type. Address AtomicInfo::materializeRValue(RValue rvalue) const { // Aggregate r-values are already in memory, and EmitAtomicStore // requires them to be values of the atomic type. if (rvalue.isAggregate()) return rvalue.getAggregateAddress(); // Otherwise, make a temporary and materialize into it. LValue TempLV = CGF.MakeAddrLValue(CreateTempAlloca(), getAtomicType()); AtomicInfo Atomics(CGF, TempLV); Atomics.emitCopyIntoMemory(rvalue); return TempLV.getAddress(CGF); } llvm::Value *AtomicInfo::convertRValueToInt(RValue RVal) const { // If we've got a scalar value of the right size, try to avoid going // through memory. if (RVal.isScalar() && (!hasPadding() || !LVal.isSimple())) { llvm::Value *Value = RVal.getScalarVal(); if (isa(Value->getType())) return CGF.EmitToMemory(Value, ValueTy); else { llvm::IntegerType *InputIntTy = llvm::IntegerType::get( CGF.getLLVMContext(), LVal.isSimple() ? getValueSizeInBits() : getAtomicSizeInBits()); if (isa(Value->getType())) return CGF.Builder.CreatePtrToInt(Value, InputIntTy); else if (llvm::BitCastInst::isBitCastable(Value->getType(), InputIntTy)) return CGF.Builder.CreateBitCast(Value, InputIntTy); } } // Otherwise, we need to go through memory. // Put the r-value in memory. Address Addr = materializeRValue(RVal); // Cast the temporary to the atomic int type and pull a value out. Addr = emitCastToAtomicIntPointer(Addr); return CGF.Builder.CreateLoad(Addr); } std::pair AtomicInfo::EmitAtomicCompareExchangeOp( llvm::Value *ExpectedVal, llvm::Value *DesiredVal, llvm::AtomicOrdering Success, llvm::AtomicOrdering Failure, bool IsWeak) { // Do the atomic store. Address Addr = getAtomicAddressAsAtomicIntPointer(); auto *Inst = CGF.Builder.CreateAtomicCmpXchg(Addr.getPointer(), ExpectedVal, DesiredVal, Success, Failure); // Other decoration. Inst->setVolatile(LVal.isVolatileQualified()); Inst->setWeak(IsWeak); // Okay, turn that back into the original value type. auto *PreviousVal = CGF.Builder.CreateExtractValue(Inst, /*Idxs=*/0); auto *SuccessFailureVal = CGF.Builder.CreateExtractValue(Inst, /*Idxs=*/1); return std::make_pair(PreviousVal, SuccessFailureVal); } llvm::Value * AtomicInfo::EmitAtomicCompareExchangeLibcall(llvm::Value *ExpectedAddr, llvm::Value *DesiredAddr, llvm::AtomicOrdering Success, llvm::AtomicOrdering Failure) { // bool __atomic_compare_exchange(size_t size, void *obj, void *expected, // void *desired, int success, int failure); CallArgList Args; Args.add(RValue::get(getAtomicSizeValue()), CGF.getContext().getSizeType()); Args.add(RValue::get(CGF.EmitCastToVoidPtr(getAtomicPointer())), CGF.getContext().VoidPtrTy); Args.add(RValue::get(CGF.EmitCastToVoidPtr(ExpectedAddr)), CGF.getContext().VoidPtrTy); Args.add(RValue::get(CGF.EmitCastToVoidPtr(DesiredAddr)), CGF.getContext().VoidPtrTy); Args.add(RValue::get( llvm::ConstantInt::get(CGF.IntTy, (int)llvm::toCABI(Success))), CGF.getContext().IntTy); Args.add(RValue::get( llvm::ConstantInt::get(CGF.IntTy, (int)llvm::toCABI(Failure))), CGF.getContext().IntTy); auto SuccessFailureRVal = emitAtomicLibcall(CGF, "__atomic_compare_exchange", CGF.getContext().BoolTy, Args); return SuccessFailureRVal.getScalarVal(); } std::pair AtomicInfo::EmitAtomicCompareExchange( RValue Expected, RValue Desired, llvm::AtomicOrdering Success, llvm::AtomicOrdering Failure, bool IsWeak) { if (isStrongerThan(Failure, Success)) // Don't assert on undefined behavior "failure argument shall be no stronger // than the success argument". Failure = llvm::AtomicCmpXchgInst::getStrongestFailureOrdering(Success); // Check whether we should use a library call. if (shouldUseLibcall()) { // Produce a source address. Address ExpectedAddr = materializeRValue(Expected); Address DesiredAddr = materializeRValue(Desired); auto *Res = EmitAtomicCompareExchangeLibcall(ExpectedAddr.getPointer(), DesiredAddr.getPointer(), Success, Failure); return std::make_pair( convertAtomicTempToRValue(ExpectedAddr, AggValueSlot::ignored(), SourceLocation(), /*AsValue=*/false), Res); } // If we've got a scalar value of the right size, try to avoid going // through memory. auto *ExpectedVal = convertRValueToInt(Expected); auto *DesiredVal = convertRValueToInt(Desired); auto Res = EmitAtomicCompareExchangeOp(ExpectedVal, DesiredVal, Success, Failure, IsWeak); return std::make_pair( ConvertIntToValueOrAtomic(Res.first, AggValueSlot::ignored(), SourceLocation(), /*AsValue=*/false), Res.second); } static void EmitAtomicUpdateValue(CodeGenFunction &CGF, AtomicInfo &Atomics, RValue OldRVal, const llvm::function_ref &UpdateOp, Address DesiredAddr) { RValue UpRVal; LValue AtomicLVal = Atomics.getAtomicLValue(); LValue DesiredLVal; if (AtomicLVal.isSimple()) { UpRVal = OldRVal; DesiredLVal = CGF.MakeAddrLValue(DesiredAddr, AtomicLVal.getType()); } else { // Build new lvalue for temp address. Address Ptr = Atomics.materializeRValue(OldRVal); LValue UpdateLVal; if (AtomicLVal.isBitField()) { UpdateLVal = LValue::MakeBitfield(Ptr, AtomicLVal.getBitFieldInfo(), AtomicLVal.getType(), AtomicLVal.getBaseInfo(), AtomicLVal.getTBAAInfo()); DesiredLVal = LValue::MakeBitfield(DesiredAddr, AtomicLVal.getBitFieldInfo(), AtomicLVal.getType(), AtomicLVal.getBaseInfo(), AtomicLVal.getTBAAInfo()); } else if (AtomicLVal.isVectorElt()) { UpdateLVal = LValue::MakeVectorElt(Ptr, AtomicLVal.getVectorIdx(), AtomicLVal.getType(), AtomicLVal.getBaseInfo(), AtomicLVal.getTBAAInfo()); DesiredLVal = LValue::MakeVectorElt( DesiredAddr, AtomicLVal.getVectorIdx(), AtomicLVal.getType(), AtomicLVal.getBaseInfo(), AtomicLVal.getTBAAInfo()); } else { assert(AtomicLVal.isExtVectorElt()); UpdateLVal = LValue::MakeExtVectorElt(Ptr, AtomicLVal.getExtVectorElts(), AtomicLVal.getType(), AtomicLVal.getBaseInfo(), AtomicLVal.getTBAAInfo()); DesiredLVal = LValue::MakeExtVectorElt( DesiredAddr, AtomicLVal.getExtVectorElts(), AtomicLVal.getType(), AtomicLVal.getBaseInfo(), AtomicLVal.getTBAAInfo()); } UpRVal = CGF.EmitLoadOfLValue(UpdateLVal, SourceLocation()); } // Store new value in the corresponding memory area. RValue NewRVal = UpdateOp(UpRVal); if (NewRVal.isScalar()) { CGF.EmitStoreThroughLValue(NewRVal, DesiredLVal); } else { assert(NewRVal.isComplex()); CGF.EmitStoreOfComplex(NewRVal.getComplexVal(), DesiredLVal, /*isInit=*/false); } } void AtomicInfo::EmitAtomicUpdateLibcall( llvm::AtomicOrdering AO, const llvm::function_ref &UpdateOp, bool IsVolatile) { auto Failure = llvm::AtomicCmpXchgInst::getStrongestFailureOrdering(AO); Address ExpectedAddr = CreateTempAlloca(); EmitAtomicLoadLibcall(ExpectedAddr.getPointer(), AO, IsVolatile); auto *ContBB = CGF.createBasicBlock("atomic_cont"); auto *ExitBB = CGF.createBasicBlock("atomic_exit"); CGF.EmitBlock(ContBB); Address DesiredAddr = CreateTempAlloca(); if ((LVal.isBitField() && BFI.Size != ValueSizeInBits) || requiresMemSetZero(getAtomicAddress().getElementType())) { auto *OldVal = CGF.Builder.CreateLoad(ExpectedAddr); CGF.Builder.CreateStore(OldVal, DesiredAddr); } auto OldRVal = convertAtomicTempToRValue(ExpectedAddr, AggValueSlot::ignored(), SourceLocation(), /*AsValue=*/false); EmitAtomicUpdateValue(CGF, *this, OldRVal, UpdateOp, DesiredAddr); auto *Res = EmitAtomicCompareExchangeLibcall(ExpectedAddr.getPointer(), DesiredAddr.getPointer(), AO, Failure); CGF.Builder.CreateCondBr(Res, ExitBB, ContBB); CGF.EmitBlock(ExitBB, /*IsFinished=*/true); } void AtomicInfo::EmitAtomicUpdateOp( llvm::AtomicOrdering AO, const llvm::function_ref &UpdateOp, bool IsVolatile) { auto Failure = llvm::AtomicCmpXchgInst::getStrongestFailureOrdering(AO); // Do the atomic load. auto *OldVal = EmitAtomicLoadOp(Failure, IsVolatile); // For non-simple lvalues perform compare-and-swap procedure. auto *ContBB = CGF.createBasicBlock("atomic_cont"); auto *ExitBB = CGF.createBasicBlock("atomic_exit"); auto *CurBB = CGF.Builder.GetInsertBlock(); CGF.EmitBlock(ContBB); llvm::PHINode *PHI = CGF.Builder.CreatePHI(OldVal->getType(), /*NumReservedValues=*/2); PHI->addIncoming(OldVal, CurBB); Address NewAtomicAddr = CreateTempAlloca(); Address NewAtomicIntAddr = emitCastToAtomicIntPointer(NewAtomicAddr); if ((LVal.isBitField() && BFI.Size != ValueSizeInBits) || requiresMemSetZero(getAtomicAddress().getElementType())) { CGF.Builder.CreateStore(PHI, NewAtomicIntAddr); } auto OldRVal = ConvertIntToValueOrAtomic(PHI, AggValueSlot::ignored(), SourceLocation(), /*AsValue=*/false); EmitAtomicUpdateValue(CGF, *this, OldRVal, UpdateOp, NewAtomicAddr); auto *DesiredVal = CGF.Builder.CreateLoad(NewAtomicIntAddr); // Try to write new value using cmpxchg operation. auto Res = EmitAtomicCompareExchangeOp(PHI, DesiredVal, AO, Failure); PHI->addIncoming(Res.first, CGF.Builder.GetInsertBlock()); CGF.Builder.CreateCondBr(Res.second, ExitBB, ContBB); CGF.EmitBlock(ExitBB, /*IsFinished=*/true); } static void EmitAtomicUpdateValue(CodeGenFunction &CGF, AtomicInfo &Atomics, RValue UpdateRVal, Address DesiredAddr) { LValue AtomicLVal = Atomics.getAtomicLValue(); LValue DesiredLVal; // Build new lvalue for temp address. if (AtomicLVal.isBitField()) { DesiredLVal = LValue::MakeBitfield(DesiredAddr, AtomicLVal.getBitFieldInfo(), AtomicLVal.getType(), AtomicLVal.getBaseInfo(), AtomicLVal.getTBAAInfo()); } else if (AtomicLVal.isVectorElt()) { DesiredLVal = LValue::MakeVectorElt(DesiredAddr, AtomicLVal.getVectorIdx(), AtomicLVal.getType(), AtomicLVal.getBaseInfo(), AtomicLVal.getTBAAInfo()); } else { assert(AtomicLVal.isExtVectorElt()); DesiredLVal = LValue::MakeExtVectorElt( DesiredAddr, AtomicLVal.getExtVectorElts(), AtomicLVal.getType(), AtomicLVal.getBaseInfo(), AtomicLVal.getTBAAInfo()); } // Store new value in the corresponding memory area. assert(UpdateRVal.isScalar()); CGF.EmitStoreThroughLValue(UpdateRVal, DesiredLVal); } void AtomicInfo::EmitAtomicUpdateLibcall(llvm::AtomicOrdering AO, RValue UpdateRVal, bool IsVolatile) { auto Failure = llvm::AtomicCmpXchgInst::getStrongestFailureOrdering(AO); Address ExpectedAddr = CreateTempAlloca(); EmitAtomicLoadLibcall(ExpectedAddr.getPointer(), AO, IsVolatile); auto *ContBB = CGF.createBasicBlock("atomic_cont"); auto *ExitBB = CGF.createBasicBlock("atomic_exit"); CGF.EmitBlock(ContBB); Address DesiredAddr = CreateTempAlloca(); if ((LVal.isBitField() && BFI.Size != ValueSizeInBits) || requiresMemSetZero(getAtomicAddress().getElementType())) { auto *OldVal = CGF.Builder.CreateLoad(ExpectedAddr); CGF.Builder.CreateStore(OldVal, DesiredAddr); } EmitAtomicUpdateValue(CGF, *this, UpdateRVal, DesiredAddr); auto *Res = EmitAtomicCompareExchangeLibcall(ExpectedAddr.getPointer(), DesiredAddr.getPointer(), AO, Failure); CGF.Builder.CreateCondBr(Res, ExitBB, ContBB); CGF.EmitBlock(ExitBB, /*IsFinished=*/true); } void AtomicInfo::EmitAtomicUpdateOp(llvm::AtomicOrdering AO, RValue UpdateRVal, bool IsVolatile) { auto Failure = llvm::AtomicCmpXchgInst::getStrongestFailureOrdering(AO); // Do the atomic load. auto *OldVal = EmitAtomicLoadOp(Failure, IsVolatile); // For non-simple lvalues perform compare-and-swap procedure. auto *ContBB = CGF.createBasicBlock("atomic_cont"); auto *ExitBB = CGF.createBasicBlock("atomic_exit"); auto *CurBB = CGF.Builder.GetInsertBlock(); CGF.EmitBlock(ContBB); llvm::PHINode *PHI = CGF.Builder.CreatePHI(OldVal->getType(), /*NumReservedValues=*/2); PHI->addIncoming(OldVal, CurBB); Address NewAtomicAddr = CreateTempAlloca(); Address NewAtomicIntAddr = emitCastToAtomicIntPointer(NewAtomicAddr); if ((LVal.isBitField() && BFI.Size != ValueSizeInBits) || requiresMemSetZero(getAtomicAddress().getElementType())) { CGF.Builder.CreateStore(PHI, NewAtomicIntAddr); } EmitAtomicUpdateValue(CGF, *this, UpdateRVal, NewAtomicAddr); auto *DesiredVal = CGF.Builder.CreateLoad(NewAtomicIntAddr); // Try to write new value using cmpxchg operation. auto Res = EmitAtomicCompareExchangeOp(PHI, DesiredVal, AO, Failure); PHI->addIncoming(Res.first, CGF.Builder.GetInsertBlock()); CGF.Builder.CreateCondBr(Res.second, ExitBB, ContBB); CGF.EmitBlock(ExitBB, /*IsFinished=*/true); } void AtomicInfo::EmitAtomicUpdate( llvm::AtomicOrdering AO, const llvm::function_ref &UpdateOp, bool IsVolatile) { if (shouldUseLibcall()) { EmitAtomicUpdateLibcall(AO, UpdateOp, IsVolatile); } else { EmitAtomicUpdateOp(AO, UpdateOp, IsVolatile); } } void AtomicInfo::EmitAtomicUpdate(llvm::AtomicOrdering AO, RValue UpdateRVal, bool IsVolatile) { if (shouldUseLibcall()) { EmitAtomicUpdateLibcall(AO, UpdateRVal, IsVolatile); } else { EmitAtomicUpdateOp(AO, UpdateRVal, IsVolatile); } } void CodeGenFunction::EmitAtomicStore(RValue rvalue, LValue lvalue, bool isInit) { bool IsVolatile = lvalue.isVolatileQualified(); llvm::AtomicOrdering AO; if (lvalue.getType()->isAtomicType()) { AO = llvm::AtomicOrdering::SequentiallyConsistent; } else { AO = llvm::AtomicOrdering::Release; IsVolatile = true; } return EmitAtomicStore(rvalue, lvalue, AO, IsVolatile, isInit); } /// Emit a store to an l-value of atomic type. /// /// Note that the r-value is expected to be an r-value *of the atomic /// type*; this means that for aggregate r-values, it should include /// storage for any padding that was necessary. void CodeGenFunction::EmitAtomicStore(RValue rvalue, LValue dest, llvm::AtomicOrdering AO, bool IsVolatile, bool isInit) { // If this is an aggregate r-value, it should agree in type except // maybe for address-space qualification. assert(!rvalue.isAggregate() || rvalue.getAggregateAddress().getElementType() == dest.getAddress(*this).getElementType()); AtomicInfo atomics(*this, dest); LValue LVal = atomics.getAtomicLValue(); // If this is an initialization, just put the value there normally. if (LVal.isSimple()) { if (isInit) { atomics.emitCopyIntoMemory(rvalue); return; } // Check whether we should use a library call. if (atomics.shouldUseLibcall()) { // Produce a source address. Address srcAddr = atomics.materializeRValue(rvalue); // void __atomic_store(size_t size, void *mem, void *val, int order) CallArgList args; args.add(RValue::get(atomics.getAtomicSizeValue()), getContext().getSizeType()); args.add(RValue::get(EmitCastToVoidPtr(atomics.getAtomicPointer())), getContext().VoidPtrTy); args.add(RValue::get(EmitCastToVoidPtr(srcAddr.getPointer())), getContext().VoidPtrTy); args.add( RValue::get(llvm::ConstantInt::get(IntTy, (int)llvm::toCABI(AO))), getContext().IntTy); emitAtomicLibcall(*this, "__atomic_store", getContext().VoidTy, args); return; } // Okay, we're doing this natively. llvm::Value *intValue = atomics.convertRValueToInt(rvalue); // Do the atomic store. Address addr = atomics.emitCastToAtomicIntPointer(atomics.getAtomicAddress()); intValue = Builder.CreateIntCast( intValue, addr.getElementType(), /*isSigned=*/false); llvm::StoreInst *store = Builder.CreateStore(intValue, addr); if (AO == llvm::AtomicOrdering::Acquire) AO = llvm::AtomicOrdering::Monotonic; else if (AO == llvm::AtomicOrdering::AcquireRelease) AO = llvm::AtomicOrdering::Release; // Initializations don't need to be atomic. if (!isInit) store->setAtomic(AO); // Other decoration. if (IsVolatile) store->setVolatile(true); CGM.DecorateInstructionWithTBAA(store, dest.getTBAAInfo()); return; } // Emit simple atomic update operation. atomics.EmitAtomicUpdate(AO, rvalue, IsVolatile); } /// Emit a compare-and-exchange op for atomic type. /// std::pair CodeGenFunction::EmitAtomicCompareExchange( LValue Obj, RValue Expected, RValue Desired, SourceLocation Loc, llvm::AtomicOrdering Success, llvm::AtomicOrdering Failure, bool IsWeak, AggValueSlot Slot) { // If this is an aggregate r-value, it should agree in type except // maybe for address-space qualification. assert(!Expected.isAggregate() || Expected.getAggregateAddress().getElementType() == Obj.getAddress(*this).getElementType()); assert(!Desired.isAggregate() || Desired.getAggregateAddress().getElementType() == Obj.getAddress(*this).getElementType()); AtomicInfo Atomics(*this, Obj); return Atomics.EmitAtomicCompareExchange(Expected, Desired, Success, Failure, IsWeak); } void CodeGenFunction::EmitAtomicUpdate( LValue LVal, llvm::AtomicOrdering AO, const llvm::function_ref &UpdateOp, bool IsVolatile) { AtomicInfo Atomics(*this, LVal); Atomics.EmitAtomicUpdate(AO, UpdateOp, IsVolatile); } void CodeGenFunction::EmitAtomicInit(Expr *init, LValue dest) { AtomicInfo atomics(*this, dest); switch (atomics.getEvaluationKind()) { case TEK_Scalar: { llvm::Value *value = EmitScalarExpr(init); atomics.emitCopyIntoMemory(RValue::get(value)); return; } case TEK_Complex: { ComplexPairTy value = EmitComplexExpr(init); atomics.emitCopyIntoMemory(RValue::getComplex(value)); return; } case TEK_Aggregate: { // Fix up the destination if the initializer isn't an expression // of atomic type. bool Zeroed = false; if (!init->getType()->isAtomicType()) { Zeroed = atomics.emitMemSetZeroIfNecessary(); dest = atomics.projectValue(); } // Evaluate the expression directly into the destination. AggValueSlot slot = AggValueSlot::forLValue( dest, *this, AggValueSlot::IsNotDestructed, AggValueSlot::DoesNotNeedGCBarriers, AggValueSlot::IsNotAliased, AggValueSlot::DoesNotOverlap, Zeroed ? AggValueSlot::IsZeroed : AggValueSlot::IsNotZeroed); EmitAggExpr(init, slot); return; } } llvm_unreachable("bad evaluation kind"); }