| //===--- CGAtomic.cpp - Emit LLVM IR for atomic operations ----------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file contains the code for emitting atomic operations. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "CodeGenFunction.h" |
| #include "CGCall.h" |
| #include "CodeGenModule.h" |
| #include "clang/AST/ASTContext.h" |
| #include "llvm/IR/DataLayout.h" |
| #include "llvm/IR/Intrinsics.h" |
| #include "llvm/IR/Operator.h" |
| |
| using namespace clang; |
| using namespace CodeGen; |
| |
| // The ABI values for various atomic memory orderings. |
| enum AtomicOrderingKind { |
| AO_ABI_memory_order_relaxed = 0, |
| AO_ABI_memory_order_consume = 1, |
| AO_ABI_memory_order_acquire = 2, |
| AO_ABI_memory_order_release = 3, |
| AO_ABI_memory_order_acq_rel = 4, |
| AO_ABI_memory_order_seq_cst = 5 |
| }; |
| |
| namespace { |
| class AtomicInfo { |
| CodeGenFunction &CGF; |
| QualType AtomicTy; |
| QualType ValueTy; |
| uint64_t AtomicSizeInBits; |
| uint64_t ValueSizeInBits; |
| CharUnits AtomicAlign; |
| CharUnits ValueAlign; |
| CharUnits LValueAlign; |
| TypeEvaluationKind EvaluationKind; |
| bool UseLibcall; |
| public: |
| AtomicInfo(CodeGenFunction &CGF, LValue &lvalue) : CGF(CGF) { |
| assert(lvalue.isSimple()); |
| |
| AtomicTy = lvalue.getType(); |
| ValueTy = AtomicTy->castAs<AtomicType>()->getValueType(); |
| EvaluationKind = CGF.getEvaluationKind(ValueTy); |
| |
| ASTContext &C = CGF.getContext(); |
| |
| uint64_t valueAlignInBits; |
| llvm::tie(ValueSizeInBits, valueAlignInBits) = C.getTypeInfo(ValueTy); |
| |
| uint64_t atomicAlignInBits; |
| llvm::tie(AtomicSizeInBits, atomicAlignInBits) = C.getTypeInfo(AtomicTy); |
| |
| assert(ValueSizeInBits <= AtomicSizeInBits); |
| assert(valueAlignInBits <= atomicAlignInBits); |
| |
| AtomicAlign = C.toCharUnitsFromBits(atomicAlignInBits); |
| ValueAlign = C.toCharUnitsFromBits(valueAlignInBits); |
| if (lvalue.getAlignment().isZero()) |
| lvalue.setAlignment(AtomicAlign); |
| |
| UseLibcall = |
| (AtomicSizeInBits > uint64_t(C.toBits(lvalue.getAlignment())) || |
| AtomicSizeInBits > C.getTargetInfo().getMaxAtomicInlineWidth()); |
| } |
| |
| QualType getAtomicType() const { return AtomicTy; } |
| QualType getValueType() const { return ValueTy; } |
| CharUnits getAtomicAlignment() const { return AtomicAlign; } |
| CharUnits getValueAlignment() const { return ValueAlign; } |
| uint64_t getAtomicSizeInBits() const { return AtomicSizeInBits; } |
| uint64_t getValueSizeInBits() const { return AtomicSizeInBits; } |
| TypeEvaluationKind getEvaluationKind() const { return EvaluationKind; } |
| bool shouldUseLibcall() const { return UseLibcall; } |
| |
| /// 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); |
| } |
| |
| void emitMemSetZeroIfNecessary(LValue dest) 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. |
| llvm::Value *emitCastToAtomicIntPointer(llvm::Value *addr) const; |
| |
| /// Turn an atomic-layout object into an r-value. |
| RValue convertTempToRValue(llvm::Value *addr, |
| AggValueSlot resultSlot) const; |
| |
| /// Copy an atomic r-value into atomic-layout memory. |
| void emitCopyIntoMemory(RValue rvalue, LValue lvalue) const; |
| |
| /// Project an l-value down to the value field. |
| LValue projectValue(LValue lvalue) const { |
| llvm::Value *addr = lvalue.getAddress(); |
| if (hasPadding()) |
| addr = CGF.Builder.CreateStructGEP(addr, 0); |
| |
| return LValue::MakeAddr(addr, getValueType(), lvalue.getAlignment(), |
| CGF.getContext(), lvalue.getTBAAInfo()); |
| } |
| |
| /// Materialize an atomic r-value in atomic-layout memory. |
| llvm::Value *materializeRValue(RValue rvalue) const; |
| |
| private: |
| bool requiresMemSetZero(llvm::Type *type) const; |
| }; |
| } |
| |
| static RValue emitAtomicLibcall(CodeGenFunction &CGF, |
| StringRef fnName, |
| QualType resultType, |
| CallArgList &args) { |
| const CGFunctionInfo &fnInfo = |
| CGF.CGM.getTypes().arrangeFreeFunctionCall(resultType, args, |
| FunctionType::ExtInfo(), RequiredArgs::All); |
| llvm::FunctionType *fnTy = CGF.CGM.getTypes().GetFunctionType(fnInfo); |
| llvm::Constant *fn = CGF.CGM.CreateRuntimeFunction(fnTy, fnName); |
| return CGF.EmitCall(fnInfo, fn, 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); |
| |
| // Just be pessimistic about aggregates. |
| case TEK_Aggregate: |
| return true; |
| } |
| llvm_unreachable("bad evaluation kind"); |
| } |
| |
| void AtomicInfo::emitMemSetZeroIfNecessary(LValue dest) const { |
| llvm::Value *addr = dest.getAddress(); |
| if (!requiresMemSetZero(addr->getType()->getPointerElementType())) |
| return; |
| |
| CGF.Builder.CreateMemSet(addr, llvm::ConstantInt::get(CGF.Int8Ty, 0), |
| AtomicSizeInBits / 8, |
| dest.getAlignment().getQuantity()); |
| } |
| |
| static void |
| EmitAtomicOp(CodeGenFunction &CGF, AtomicExpr *E, llvm::Value *Dest, |
| llvm::Value *Ptr, llvm::Value *Val1, llvm::Value *Val2, |
| uint64_t Size, unsigned Align, llvm::AtomicOrdering Order) { |
| llvm::AtomicRMWInst::BinOp Op = llvm::AtomicRMWInst::Add; |
| llvm::Instruction::BinaryOps PostOp = (llvm::Instruction::BinaryOps)0; |
| |
| switch (E->getOp()) { |
| case AtomicExpr::AO__c11_atomic_init: |
| llvm_unreachable("Already handled!"); |
| |
| case AtomicExpr::AO__c11_atomic_compare_exchange_strong: |
| case AtomicExpr::AO__c11_atomic_compare_exchange_weak: |
| case AtomicExpr::AO__atomic_compare_exchange: |
| case AtomicExpr::AO__atomic_compare_exchange_n: { |
| // Note that cmpxchg only supports specifying one ordering and |
| // doesn't support weak cmpxchg, at least at the moment. |
| llvm::LoadInst *LoadVal1 = CGF.Builder.CreateLoad(Val1); |
| LoadVal1->setAlignment(Align); |
| llvm::LoadInst *LoadVal2 = CGF.Builder.CreateLoad(Val2); |
| LoadVal2->setAlignment(Align); |
| llvm::AtomicCmpXchgInst *CXI = |
| CGF.Builder.CreateAtomicCmpXchg(Ptr, LoadVal1, LoadVal2, Order); |
| CXI->setVolatile(E->isVolatile()); |
| llvm::StoreInst *StoreVal1 = CGF.Builder.CreateStore(CXI, Val1); |
| StoreVal1->setAlignment(Align); |
| llvm::Value *Cmp = CGF.Builder.CreateICmpEQ(CXI, LoadVal1); |
| CGF.EmitStoreOfScalar(Cmp, CGF.MakeAddrLValue(Dest, E->getType())); |
| return; |
| } |
| |
| case AtomicExpr::AO__c11_atomic_load: |
| case AtomicExpr::AO__atomic_load_n: |
| case AtomicExpr::AO__atomic_load: { |
| llvm::LoadInst *Load = CGF.Builder.CreateLoad(Ptr); |
| Load->setAtomic(Order); |
| Load->setAlignment(Size); |
| Load->setVolatile(E->isVolatile()); |
| llvm::StoreInst *StoreDest = CGF.Builder.CreateStore(Load, Dest); |
| StoreDest->setAlignment(Align); |
| return; |
| } |
| |
| case AtomicExpr::AO__c11_atomic_store: |
| case AtomicExpr::AO__atomic_store: |
| case AtomicExpr::AO__atomic_store_n: { |
| assert(!Dest && "Store does not return a value"); |
| llvm::LoadInst *LoadVal1 = CGF.Builder.CreateLoad(Val1); |
| LoadVal1->setAlignment(Align); |
| llvm::StoreInst *Store = CGF.Builder.CreateStore(LoadVal1, Ptr); |
| Store->setAtomic(Order); |
| Store->setAlignment(Size); |
| Store->setVolatile(E->isVolatile()); |
| return; |
| } |
| |
| case AtomicExpr::AO__c11_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 = llvm::Instruction::Add; |
| // Fall through. |
| case AtomicExpr::AO__c11_atomic_fetch_add: |
| case AtomicExpr::AO__atomic_fetch_add: |
| Op = llvm::AtomicRMWInst::Add; |
| break; |
| |
| case AtomicExpr::AO__atomic_sub_fetch: |
| PostOp = llvm::Instruction::Sub; |
| // Fall through. |
| case AtomicExpr::AO__c11_atomic_fetch_sub: |
| case AtomicExpr::AO__atomic_fetch_sub: |
| Op = llvm::AtomicRMWInst::Sub; |
| break; |
| |
| case AtomicExpr::AO__atomic_and_fetch: |
| PostOp = llvm::Instruction::And; |
| // Fall through. |
| case AtomicExpr::AO__c11_atomic_fetch_and: |
| case AtomicExpr::AO__atomic_fetch_and: |
| Op = llvm::AtomicRMWInst::And; |
| break; |
| |
| case AtomicExpr::AO__atomic_or_fetch: |
| PostOp = llvm::Instruction::Or; |
| // Fall through. |
| case AtomicExpr::AO__c11_atomic_fetch_or: |
| case AtomicExpr::AO__atomic_fetch_or: |
| Op = llvm::AtomicRMWInst::Or; |
| break; |
| |
| case AtomicExpr::AO__atomic_xor_fetch: |
| PostOp = llvm::Instruction::Xor; |
| // Fall through. |
| case AtomicExpr::AO__c11_atomic_fetch_xor: |
| case AtomicExpr::AO__atomic_fetch_xor: |
| Op = llvm::AtomicRMWInst::Xor; |
| break; |
| |
| case AtomicExpr::AO__atomic_nand_fetch: |
| PostOp = llvm::Instruction::And; |
| // Fall through. |
| case AtomicExpr::AO__atomic_fetch_nand: |
| Op = llvm::AtomicRMWInst::Nand; |
| break; |
| } |
| |
| llvm::LoadInst *LoadVal1 = CGF.Builder.CreateLoad(Val1); |
| LoadVal1->setAlignment(Align); |
| llvm::AtomicRMWInst *RMWI = |
| CGF.Builder.CreateAtomicRMW(Op, Ptr, LoadVal1, Order); |
| RMWI->setVolatile(E->isVolatile()); |
| |
| // For __atomic_*_fetch operations, perform the operation again to |
| // determine the value which was written. |
| llvm::Value *Result = RMWI; |
| if (PostOp) |
| Result = CGF.Builder.CreateBinOp(PostOp, RMWI, LoadVal1); |
| if (E->getOp() == AtomicExpr::AO__atomic_nand_fetch) |
| Result = CGF.Builder.CreateNot(Result); |
| llvm::StoreInst *StoreDest = CGF.Builder.CreateStore(Result, Dest); |
| StoreDest->setAlignment(Align); |
| } |
| |
| // This function emits any expression (scalar, complex, or aggregate) |
| // into a temporary alloca. |
| static llvm::Value * |
| EmitValToTemp(CodeGenFunction &CGF, Expr *E) { |
| llvm::Value *DeclPtr = CGF.CreateMemTemp(E->getType(), ".atomictmp"); |
| CGF.EmitAnyExprToMem(E, DeclPtr, E->getType().getQualifiers(), |
| /*Init*/ true); |
| return DeclPtr; |
| } |
| |
| RValue CodeGenFunction::EmitAtomicExpr(AtomicExpr *E, llvm::Value *Dest) { |
| QualType AtomicTy = E->getPtr()->getType()->getPointeeType(); |
| QualType MemTy = AtomicTy; |
| if (const AtomicType *AT = AtomicTy->getAs<AtomicType>()) |
| MemTy = AT->getValueType(); |
| CharUnits sizeChars = getContext().getTypeSizeInChars(AtomicTy); |
| uint64_t Size = sizeChars.getQuantity(); |
| CharUnits alignChars = getContext().getTypeAlignInChars(AtomicTy); |
| unsigned Align = alignChars.getQuantity(); |
| unsigned MaxInlineWidthInBits = |
| getContext().getTargetInfo().getMaxAtomicInlineWidth(); |
| bool UseLibcall = (Size != Align || |
| getContext().toBits(sizeChars) > MaxInlineWidthInBits); |
| |
| llvm::Value *Ptr, *Order, *OrderFail = 0, *Val1 = 0, *Val2 = 0; |
| Ptr = EmitScalarExpr(E->getPtr()); |
| |
| if (E->getOp() == AtomicExpr::AO__c11_atomic_init) { |
| assert(!Dest && "Init does not return a value"); |
| LValue lvalue = LValue::MakeAddr(Ptr, AtomicTy, alignChars, getContext()); |
| EmitAtomicInit(E->getVal1(), lvalue); |
| return RValue::get(0); |
| } |
| |
| Order = EmitScalarExpr(E->getOrder()); |
| |
| switch (E->getOp()) { |
| case AtomicExpr::AO__c11_atomic_init: |
| llvm_unreachable("Already handled!"); |
| |
| case AtomicExpr::AO__c11_atomic_load: |
| case AtomicExpr::AO__atomic_load_n: |
| break; |
| |
| case AtomicExpr::AO__atomic_load: |
| Dest = EmitScalarExpr(E->getVal1()); |
| break; |
| |
| case AtomicExpr::AO__atomic_store: |
| Val1 = EmitScalarExpr(E->getVal1()); |
| break; |
| |
| case AtomicExpr::AO__atomic_exchange: |
| Val1 = EmitScalarExpr(E->getVal1()); |
| Dest = EmitScalarExpr(E->getVal2()); |
| break; |
| |
| case AtomicExpr::AO__c11_atomic_compare_exchange_strong: |
| case AtomicExpr::AO__c11_atomic_compare_exchange_weak: |
| case AtomicExpr::AO__atomic_compare_exchange_n: |
| case AtomicExpr::AO__atomic_compare_exchange: |
| Val1 = EmitScalarExpr(E->getVal1()); |
| if (E->getOp() == AtomicExpr::AO__atomic_compare_exchange) |
| Val2 = EmitScalarExpr(E->getVal2()); |
| else |
| Val2 = EmitValToTemp(*this, E->getVal2()); |
| OrderFail = EmitScalarExpr(E->getOrderFail()); |
| // Evaluate and discard the 'weak' argument. |
| if (E->getNumSubExprs() == 6) |
| EmitScalarExpr(E->getWeak()); |
| break; |
| |
| case AtomicExpr::AO__c11_atomic_fetch_add: |
| case AtomicExpr::AO__c11_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)); |
| Val1 = CreateMemTemp(Val1Ty, ".atomictmp"); |
| EmitStoreOfScalar(Val1Scalar, MakeAddrLValue(Val1, Val1Ty)); |
| break; |
| } |
| // Fall through. |
| case AtomicExpr::AO__atomic_fetch_add: |
| case AtomicExpr::AO__atomic_fetch_sub: |
| case AtomicExpr::AO__atomic_add_fetch: |
| case AtomicExpr::AO__atomic_sub_fetch: |
| case AtomicExpr::AO__c11_atomic_store: |
| case AtomicExpr::AO__c11_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__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: |
| Val1 = EmitValToTemp(*this, E->getVal1()); |
| break; |
| } |
| |
| if (!E->getType()->isVoidType() && !Dest) |
| Dest = CreateMemTemp(E->getType(), ".atomicdst"); |
| |
| // Use a library call. See: http://gcc.gnu.org/wiki/Atomic/GCCMM/LIbrary . |
| if (UseLibcall) { |
| |
| SmallVector<QualType, 5> Params; |
| CallArgList Args; |
| // Size is always the first parameter |
| Args.add(RValue::get(llvm::ConstantInt::get(SizeTy, Size)), |
| getContext().getSizeType()); |
| // Atomic address is always the second parameter |
| Args.add(RValue::get(EmitCastToVoidPtr(Ptr)), |
| getContext().VoidPtrTy); |
| |
| const char* LibCallName; |
| QualType RetTy = getContext().VoidTy; |
| switch (E->getOp()) { |
| // 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 *obj, void *expected, |
| // void *desired, int success, int failure) |
| case AtomicExpr::AO__c11_atomic_compare_exchange_weak: |
| case AtomicExpr::AO__c11_atomic_compare_exchange_strong: |
| case AtomicExpr::AO__atomic_compare_exchange: |
| case AtomicExpr::AO__atomic_compare_exchange_n: |
| LibCallName = "__atomic_compare_exchange"; |
| RetTy = getContext().BoolTy; |
| Args.add(RValue::get(EmitCastToVoidPtr(Val1)), |
| getContext().VoidPtrTy); |
| Args.add(RValue::get(EmitCastToVoidPtr(Val2)), |
| getContext().VoidPtrTy); |
| Args.add(RValue::get(Order), |
| getContext().IntTy); |
| Order = OrderFail; |
| break; |
| // void __atomic_exchange(size_t size, void *mem, void *val, void *return, |
| // int order) |
| case AtomicExpr::AO__c11_atomic_exchange: |
| case AtomicExpr::AO__atomic_exchange_n: |
| case AtomicExpr::AO__atomic_exchange: |
| LibCallName = "__atomic_exchange"; |
| Args.add(RValue::get(EmitCastToVoidPtr(Val1)), |
| getContext().VoidPtrTy); |
| Args.add(RValue::get(EmitCastToVoidPtr(Dest)), |
| getContext().VoidPtrTy); |
| break; |
| // void __atomic_store(size_t size, void *mem, void *val, int order) |
| case AtomicExpr::AO__c11_atomic_store: |
| case AtomicExpr::AO__atomic_store: |
| case AtomicExpr::AO__atomic_store_n: |
| LibCallName = "__atomic_store"; |
| Args.add(RValue::get(EmitCastToVoidPtr(Val1)), |
| getContext().VoidPtrTy); |
| break; |
| // void __atomic_load(size_t size, void *mem, void *return, int order) |
| case AtomicExpr::AO__c11_atomic_load: |
| case AtomicExpr::AO__atomic_load: |
| case AtomicExpr::AO__atomic_load_n: |
| LibCallName = "__atomic_load"; |
| Args.add(RValue::get(EmitCastToVoidPtr(Dest)), |
| getContext().VoidPtrTy); |
| break; |
| #if 0 |
| // These are only defined for 1-16 byte integers. It is not clear what |
| // their semantics would be on anything else... |
| case AtomicExpr::Add: LibCallName = "__atomic_fetch_add_generic"; break; |
| case AtomicExpr::Sub: LibCallName = "__atomic_fetch_sub_generic"; break; |
| case AtomicExpr::And: LibCallName = "__atomic_fetch_and_generic"; break; |
| case AtomicExpr::Or: LibCallName = "__atomic_fetch_or_generic"; break; |
| case AtomicExpr::Xor: LibCallName = "__atomic_fetch_xor_generic"; break; |
| #endif |
| default: return EmitUnsupportedRValue(E, "atomic library call"); |
| } |
| // order is always the last parameter |
| Args.add(RValue::get(Order), |
| getContext().IntTy); |
| |
| const CGFunctionInfo &FuncInfo = |
| CGM.getTypes().arrangeFreeFunctionCall(RetTy, Args, |
| FunctionType::ExtInfo(), RequiredArgs::All); |
| llvm::FunctionType *FTy = CGM.getTypes().GetFunctionType(FuncInfo); |
| llvm::Constant *Func = CGM.CreateRuntimeFunction(FTy, LibCallName); |
| RValue Res = EmitCall(FuncInfo, Func, ReturnValueSlot(), Args); |
| if (E->isCmpXChg()) |
| return Res; |
| if (E->getType()->isVoidType()) |
| return RValue::get(0); |
| return convertTempToRValue(Dest, E->getType()); |
| } |
| |
| bool IsStore = E->getOp() == AtomicExpr::AO__c11_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__atomic_load || |
| E->getOp() == AtomicExpr::AO__atomic_load_n; |
| |
| llvm::Type *IPtrTy = |
| llvm::IntegerType::get(getLLVMContext(), Size * 8)->getPointerTo(); |
| llvm::Value *OrigDest = Dest; |
| Ptr = Builder.CreateBitCast(Ptr, IPtrTy); |
| if (Val1) Val1 = Builder.CreateBitCast(Val1, IPtrTy); |
| if (Val2) Val2 = Builder.CreateBitCast(Val2, IPtrTy); |
| if (Dest && !E->isCmpXChg()) Dest = Builder.CreateBitCast(Dest, IPtrTy); |
| |
| if (isa<llvm::ConstantInt>(Order)) { |
| int ord = cast<llvm::ConstantInt>(Order)->getZExtValue(); |
| switch (ord) { |
| case AO_ABI_memory_order_relaxed: |
| EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, Size, Align, |
| llvm::Monotonic); |
| break; |
| case AO_ABI_memory_order_consume: |
| case AO_ABI_memory_order_acquire: |
| if (IsStore) |
| break; // Avoid crashing on code with undefined behavior |
| EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, Size, Align, |
| llvm::Acquire); |
| break; |
| case AO_ABI_memory_order_release: |
| if (IsLoad) |
| break; // Avoid crashing on code with undefined behavior |
| EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, Size, Align, |
| llvm::Release); |
| break; |
| case AO_ABI_memory_order_acq_rel: |
| if (IsLoad || IsStore) |
| break; // Avoid crashing on code with undefined behavior |
| EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, Size, Align, |
| llvm::AcquireRelease); |
| break; |
| case AO_ABI_memory_order_seq_cst: |
| EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, Size, Align, |
| llvm::SequentiallyConsistent); |
| break; |
| default: // invalid order |
| // We should not ever get here normally, but it's hard to |
| // enforce that in general. |
| break; |
| } |
| if (E->getType()->isVoidType()) |
| return RValue::get(0); |
| return convertTempToRValue(OrigDest, E->getType()); |
| } |
| |
| // Long case, when Order isn't obviously constant. |
| |
| // Create all the relevant BB's |
| llvm::BasicBlock *MonotonicBB = 0, *AcquireBB = 0, *ReleaseBB = 0, |
| *AcqRelBB = 0, *SeqCstBB = 0; |
| 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, Size, Align, |
| llvm::Monotonic); |
| Builder.CreateBr(ContBB); |
| if (!IsStore) { |
| Builder.SetInsertPoint(AcquireBB); |
| EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, Size, Align, |
| llvm::Acquire); |
| Builder.CreateBr(ContBB); |
| SI->addCase(Builder.getInt32(1), AcquireBB); |
| SI->addCase(Builder.getInt32(2), AcquireBB); |
| } |
| if (!IsLoad) { |
| Builder.SetInsertPoint(ReleaseBB); |
| EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, Size, Align, |
| llvm::Release); |
| Builder.CreateBr(ContBB); |
| SI->addCase(Builder.getInt32(3), ReleaseBB); |
| } |
| if (!IsLoad && !IsStore) { |
| Builder.SetInsertPoint(AcqRelBB); |
| EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, Size, Align, |
| llvm::AcquireRelease); |
| Builder.CreateBr(ContBB); |
| SI->addCase(Builder.getInt32(4), AcqRelBB); |
| } |
| Builder.SetInsertPoint(SeqCstBB); |
| EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, Size, Align, |
| llvm::SequentiallyConsistent); |
| Builder.CreateBr(ContBB); |
| SI->addCase(Builder.getInt32(5), SeqCstBB); |
| |
| // Cleanup and return |
| Builder.SetInsertPoint(ContBB); |
| if (E->getType()->isVoidType()) |
| return RValue::get(0); |
| return convertTempToRValue(OrigDest, E->getType()); |
| } |
| |
| llvm::Value *AtomicInfo::emitCastToAtomicIntPointer(llvm::Value *addr) const { |
| unsigned addrspace = |
| cast<llvm::PointerType>(addr->getType())->getAddressSpace(); |
| llvm::IntegerType *ty = |
| llvm::IntegerType::get(CGF.getLLVMContext(), AtomicSizeInBits); |
| return CGF.Builder.CreateBitCast(addr, ty->getPointerTo(addrspace)); |
| } |
| |
| RValue AtomicInfo::convertTempToRValue(llvm::Value *addr, |
| AggValueSlot resultSlot) const { |
| if (EvaluationKind == TEK_Aggregate) { |
| // Nothing to do if the result is ignored. |
| if (resultSlot.isIgnored()) return resultSlot.asRValue(); |
| |
| assert(resultSlot.getAddr() == addr || hasPadding()); |
| |
| // In these cases, we should have emitted directly into the result slot. |
| if (!hasPadding() || resultSlot.isValueOfAtomic()) |
| return resultSlot.asRValue(); |
| |
| // Otherwise, fall into the common path. |
| } |
| |
| // Drill into the padding structure if we have one. |
| if (hasPadding()) |
| addr = CGF.Builder.CreateStructGEP(addr, 0); |
| |
| // If we're emitting to an aggregate, copy into the result slot. |
| if (EvaluationKind == TEK_Aggregate) { |
| CGF.EmitAggregateCopy(resultSlot.getAddr(), addr, getValueType(), |
| resultSlot.isVolatile()); |
| return resultSlot.asRValue(); |
| } |
| |
| // Otherwise, just convert the temporary to an r-value using the |
| // normal conversion routine. |
| return CGF.convertTempToRValue(addr, getValueType()); |
| } |
| |
| /// 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, AggValueSlot resultSlot) { |
| AtomicInfo atomics(*this, src); |
| |
| // Check whether we should use a library call. |
| if (atomics.shouldUseLibcall()) { |
| llvm::Value *tempAddr; |
| if (resultSlot.isValueOfAtomic()) { |
| assert(atomics.getEvaluationKind() == TEK_Aggregate); |
| tempAddr = resultSlot.getPaddedAtomicAddr(); |
| } else if (!resultSlot.isIgnored() && !atomics.hasPadding()) { |
| assert(atomics.getEvaluationKind() == TEK_Aggregate); |
| tempAddr = resultSlot.getAddr(); |
| } else { |
| tempAddr = CreateMemTemp(atomics.getAtomicType(), "atomic-load-temp"); |
| } |
| |
| // void __atomic_load(size_t size, void *mem, void *return, int order); |
| CallArgList args; |
| args.add(RValue::get(atomics.getAtomicSizeValue()), |
| getContext().getSizeType()); |
| args.add(RValue::get(EmitCastToVoidPtr(src.getAddress())), |
| getContext().VoidPtrTy); |
| args.add(RValue::get(EmitCastToVoidPtr(tempAddr)), |
| getContext().VoidPtrTy); |
| args.add(RValue::get(llvm::ConstantInt::get(IntTy, |
| AO_ABI_memory_order_seq_cst)), |
| getContext().IntTy); |
| emitAtomicLibcall(*this, "__atomic_load", getContext().VoidTy, args); |
| |
| // Produce the r-value. |
| return atomics.convertTempToRValue(tempAddr, resultSlot); |
| } |
| |
| // Okay, we're doing this natively. |
| llvm::Value *addr = atomics.emitCastToAtomicIntPointer(src.getAddress()); |
| llvm::LoadInst *load = Builder.CreateLoad(addr, "atomic-load"); |
| load->setAtomic(llvm::SequentiallyConsistent); |
| |
| // Other decoration. |
| load->setAlignment(src.getAlignment().getQuantity()); |
| if (src.isVolatileQualified()) |
| load->setVolatile(true); |
| if (src.getTBAAInfo()) |
| CGM.DecorateInstruction(load, src.getTBAAInfo()); |
| |
| // Okay, turn that back into the original value type. |
| QualType valueType = atomics.getValueType(); |
| llvm::Value *result = load; |
| |
| // If we're ignoring an aggregate return, don't do anything. |
| if (atomics.getEvaluationKind() == TEK_Aggregate && resultSlot.isIgnored()) |
| return RValue::getAggregate(0, false); |
| |
| // The easiest way to do this this is to go through memory, but we |
| // try not to in some easy cases. |
| if (atomics.getEvaluationKind() == TEK_Scalar && !atomics.hasPadding()) { |
| llvm::Type *resultTy = CGM.getTypes().ConvertTypeForMem(valueType); |
| if (isa<llvm::IntegerType>(resultTy)) { |
| assert(result->getType() == resultTy); |
| result = EmitFromMemory(result, valueType); |
| } else if (isa<llvm::PointerType>(resultTy)) { |
| result = Builder.CreateIntToPtr(result, resultTy); |
| } else { |
| result = Builder.CreateBitCast(result, resultTy); |
| } |
| return RValue::get(result); |
| } |
| |
| // Create a temporary. This needs to be big enough to hold the |
| // atomic integer. |
| llvm::Value *temp; |
| bool tempIsVolatile = false; |
| CharUnits tempAlignment; |
| if (atomics.getEvaluationKind() == TEK_Aggregate && |
| (!atomics.hasPadding() || resultSlot.isValueOfAtomic())) { |
| assert(!resultSlot.isIgnored()); |
| if (resultSlot.isValueOfAtomic()) { |
| temp = resultSlot.getPaddedAtomicAddr(); |
| tempAlignment = atomics.getAtomicAlignment(); |
| } else { |
| temp = resultSlot.getAddr(); |
| tempAlignment = atomics.getValueAlignment(); |
| } |
| tempIsVolatile = resultSlot.isVolatile(); |
| } else { |
| temp = CreateMemTemp(atomics.getAtomicType(), "atomic-load-temp"); |
| tempAlignment = atomics.getAtomicAlignment(); |
| } |
| |
| // Slam the integer into the temporary. |
| llvm::Value *castTemp = atomics.emitCastToAtomicIntPointer(temp); |
| Builder.CreateAlignedStore(result, castTemp, tempAlignment.getQuantity()) |
| ->setVolatile(tempIsVolatile); |
| |
| return atomics.convertTempToRValue(temp, resultSlot); |
| } |
| |
| |
| |
| /// 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, LValue dest) const { |
| // 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()) { |
| CGF.EmitAggregateCopy(dest.getAddress(), |
| rvalue.getAggregateAddr(), |
| getAtomicType(), |
| (rvalue.isVolatileQualified() |
| || dest.isVolatileQualified()), |
| dest.getAlignment()); |
| return; |
| } |
| |
| // Okay, otherwise we're copying stuff. |
| |
| // Zero out the buffer if necessary. |
| emitMemSetZeroIfNecessary(dest); |
| |
| // Drill past the padding if present. |
| dest = projectValue(dest); |
| |
| // Okay, store the rvalue in. |
| if (rvalue.isScalar()) { |
| CGF.EmitStoreOfScalar(rvalue.getScalarVal(), dest, /*init*/ true); |
| } else { |
| CGF.EmitStoreOfComplex(rvalue.getComplexVal(), dest, /*init*/ true); |
| } |
| } |
| |
| |
| /// Materialize an r-value into memory for the purposes of storing it |
| /// to an atomic type. |
| llvm::Value *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.getAggregateAddr(); |
| |
| // Otherwise, make a temporary and materialize into it. |
| llvm::Value *temp = CGF.CreateMemTemp(getAtomicType(), "atomic-store-temp"); |
| LValue tempLV = CGF.MakeAddrLValue(temp, getAtomicType(), getAtomicAlignment()); |
| emitCopyIntoMemory(rvalue, tempLV); |
| return temp; |
| } |
| |
| /// 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, |
| bool isInit) { |
| // If this is an aggregate r-value, it should agree in type except |
| // maybe for address-space qualification. |
| assert(!rvalue.isAggregate() || |
| rvalue.getAggregateAddr()->getType()->getPointerElementType() |
| == dest.getAddress()->getType()->getPointerElementType()); |
| |
| AtomicInfo atomics(*this, dest); |
| |
| // If this is an initialization, just put the value there normally. |
| if (isInit) { |
| atomics.emitCopyIntoMemory(rvalue, dest); |
| return; |
| } |
| |
| // Check whether we should use a library call. |
| if (atomics.shouldUseLibcall()) { |
| // Produce a source address. |
| llvm::Value *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(dest.getAddress())), |
| getContext().VoidPtrTy); |
| args.add(RValue::get(EmitCastToVoidPtr(srcAddr)), |
| getContext().VoidPtrTy); |
| args.add(RValue::get(llvm::ConstantInt::get(IntTy, |
| AO_ABI_memory_order_seq_cst)), |
| getContext().IntTy); |
| emitAtomicLibcall(*this, "__atomic_store", getContext().VoidTy, args); |
| return; |
| } |
| |
| // Okay, we're doing this natively. |
| llvm::Value *intValue; |
| |
| // If we've got a scalar value of the right size, try to avoid going |
| // through memory. |
| if (rvalue.isScalar() && !atomics.hasPadding()) { |
| llvm::Value *value = rvalue.getScalarVal(); |
| if (isa<llvm::IntegerType>(value->getType())) { |
| intValue = value; |
| } else { |
| llvm::IntegerType *inputIntTy = |
| llvm::IntegerType::get(getLLVMContext(), atomics.getValueSizeInBits()); |
| if (isa<llvm::PointerType>(value->getType())) { |
| intValue = Builder.CreatePtrToInt(value, inputIntTy); |
| } else { |
| intValue = Builder.CreateBitCast(value, inputIntTy); |
| } |
| } |
| |
| // Otherwise, we need to go through memory. |
| } else { |
| // Put the r-value in memory. |
| llvm::Value *addr = atomics.materializeRValue(rvalue); |
| |
| // Cast the temporary to the atomic int type and pull a value out. |
| addr = atomics.emitCastToAtomicIntPointer(addr); |
| intValue = Builder.CreateAlignedLoad(addr, |
| atomics.getAtomicAlignment().getQuantity()); |
| } |
| |
| // Do the atomic store. |
| llvm::Value *addr = atomics.emitCastToAtomicIntPointer(dest.getAddress()); |
| llvm::StoreInst *store = Builder.CreateStore(intValue, addr); |
| |
| // Initializations don't need to be atomic. |
| if (!isInit) store->setAtomic(llvm::SequentiallyConsistent); |
| |
| // Other decoration. |
| store->setAlignment(dest.getAlignment().getQuantity()); |
| if (dest.isVolatileQualified()) |
| store->setVolatile(true); |
| if (dest.getTBAAInfo()) |
| CGM.DecorateInstruction(store, dest.getTBAAInfo()); |
| } |
| |
| 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), dest); |
| return; |
| } |
| |
| case TEK_Complex: { |
| ComplexPairTy value = EmitComplexExpr(init); |
| atomics.emitCopyIntoMemory(RValue::getComplex(value), dest); |
| return; |
| } |
| |
| case TEK_Aggregate: { |
| // Memset the buffer first if there's any possibility of |
| // uninitialized internal bits. |
| atomics.emitMemSetZeroIfNecessary(dest); |
| |
| // HACK: whether the initializer actually has an atomic type |
| // doesn't really seem reliable right now. |
| if (!init->getType()->isAtomicType()) { |
| dest = atomics.projectValue(dest); |
| } |
| |
| // Evaluate the expression directly into the destination. |
| AggValueSlot slot = AggValueSlot::forLValue(dest, |
| AggValueSlot::IsNotDestructed, |
| AggValueSlot::DoesNotNeedGCBarriers, |
| AggValueSlot::IsNotAliased); |
| EmitAggExpr(init, slot); |
| return; |
| } |
| } |
| llvm_unreachable("bad evaluation kind"); |
| } |
