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//===--- 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 "CGRecordLayout.h"
#include "CodeGenModule.h"
#include "clang/AST/ASTContext.h"
#include "clang/CodeGen/CGFunctionInfo.h"
#include "llvm/ADT/StringExtras.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;
CharUnits LValueAlign;
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<AtomicType>())
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.getAlignmentSource());
LVal.setTBAAInfo(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, ArrayType::Normal,
/*IndexTypeQuals=*/0);
}
AtomicAlign = ValueAlign = lvalue.getAlignment();
} else if (lvalue.isVectorElt()) {
ValueTy = lvalue.getType()->getAs<VectorType>()->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(), lvalue.getExtVectorAddress()
.getElementType()->getVectorNumElements());
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; }
CharUnits getValueAlignment() const { return ValueAlign; }
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();
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;
/// \brief 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, CharUnits());
return LValue::MakeAddr(addr, getValueType(), CGF.getContext(),
LVal.getAlignmentSource(), LVal.getTBAAInfo());
}
/// \brief Emits atomic load.
/// \returns Loaded value.
RValue EmitAtomicLoad(AggValueSlot ResultSlot, SourceLocation Loc,
bool AsValue, llvm::AtomicOrdering AO,
bool IsVolatile);
/// \brief 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<RValue, llvm::Value *> EmitAtomicCompareExchange(
RValue Expected, RValue Desired,
llvm::AtomicOrdering Success = llvm::SequentiallyConsistent,
llvm::AtomicOrdering Failure = llvm::SequentiallyConsistent,
bool IsWeak = false);
/// \brief Emits atomic update.
/// \param AO Atomic ordering.
/// \param UpdateOp Update operation for the current lvalue.
void EmitAtomicUpdate(llvm::AtomicOrdering AO,
const llvm::function_ref<RValue(RValue)> &UpdateOp,
bool IsVolatile);
/// \brief 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;
/// \brief Translates LLVM atomic ordering to GNU atomic ordering for
/// libcalls.
static AtomicExpr::AtomicOrderingKind
translateAtomicOrdering(const llvm::AtomicOrdering AO);
/// \brief Creates temp alloca for intermediate operations on atomic value.
Address CreateTempAlloca() const;
private:
bool requiresMemSetZero(llvm::Type *type) const;
/// \brief Emits atomic load as a libcall.
void EmitAtomicLoadLibcall(llvm::Value *AddForLoaded,
llvm::AtomicOrdering AO, bool IsVolatile);
/// \brief Emits atomic load as LLVM instruction.
llvm::Value *EmitAtomicLoadOp(llvm::AtomicOrdering AO, bool IsVolatile);
/// \brief Emits atomic compare-and-exchange op as a libcall.
llvm::Value *EmitAtomicCompareExchangeLibcall(
llvm::Value *ExpectedAddr, llvm::Value *DesiredAddr,
llvm::AtomicOrdering Success = llvm::SequentiallyConsistent,
llvm::AtomicOrdering Failure = llvm::SequentiallyConsistent);
/// \brief Emits atomic compare-and-exchange op as LLVM instruction.
std::pair<llvm::Value *, llvm::Value *> EmitAtomicCompareExchangeOp(
llvm::Value *ExpectedVal, llvm::Value *DesiredVal,
llvm::AtomicOrdering Success = llvm::SequentiallyConsistent,
llvm::AtomicOrdering Failure = llvm::SequentiallyConsistent,
bool IsWeak = false);
/// \brief Emit atomic update as libcalls.
void
EmitAtomicUpdateLibcall(llvm::AtomicOrdering AO,
const llvm::function_ref<RValue(RValue)> &UpdateOp,
bool IsVolatile);
/// \brief Emit atomic update as LLVM instructions.
void EmitAtomicUpdateOp(llvm::AtomicOrdering AO,
const llvm::function_ref<RValue(RValue)> &UpdateOp,
bool IsVolatile);
/// \brief Emit atomic update as libcalls.
void EmitAtomicUpdateLibcall(llvm::AtomicOrdering AO, RValue UpdateRVal,
bool IsVolatile);
/// \brief Emit atomic update as LLVM instructions.
void EmitAtomicUpdateOp(llvm::AtomicOrdering AO, RValue UpdateRal,
bool IsVolatile);
};
}
AtomicExpr::AtomicOrderingKind
AtomicInfo::translateAtomicOrdering(const llvm::AtomicOrdering AO) {
switch (AO) {
case llvm::Unordered:
case llvm::NotAtomic:
case llvm::Monotonic:
return AtomicExpr::AO_ABI_memory_order_relaxed;
case llvm::Acquire:
return AtomicExpr::AO_ABI_memory_order_acquire;
case llvm::Release:
return AtomicExpr::AO_ABI_memory_order_release;
case llvm::AcquireRelease:
return AtomicExpr::AO_ABI_memory_order_acq_rel;
case llvm::SequentiallyConsistent:
return AtomicExpr::AO_ABI_memory_order_seq_cst;
}
llvm_unreachable("Unhandled AtomicOrdering");
}
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().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);
// 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();
if (!requiresMemSetZero(addr->getType()->getPointerElementType()))
return false;
CGF.Builder.CreateMemSet(
addr, llvm::ConstantInt::get(CGF.Int8Ty, 0),
CGF.getContext().toCharUnitsFromBits(AtomicSizeInBits).getQuantity(),
LVal.getAlignment().getQuantity());
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) {
// 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);
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::AtomicOrdering FailureOrder;
if (llvm::ConstantInt *FO = dyn_cast<llvm::ConstantInt>(FailureOrderVal)) {
switch (FO->getSExtValue()) {
default:
FailureOrder = llvm::Monotonic;
break;
case AtomicExpr::AO_ABI_memory_order_consume:
case AtomicExpr::AO_ABI_memory_order_acquire:
FailureOrder = llvm::Acquire;
break;
case AtomicExpr::AO_ABI_memory_order_seq_cst:
FailureOrder = llvm::SequentiallyConsistent;
break;
}
if (FailureOrder >= SuccessOrder) {
// Don't assert on undefined behaviour.
FailureOrder =
llvm::AtomicCmpXchgInst::getStrongestFailureOrdering(SuccessOrder);
}
emitAtomicCmpXchg(CGF, E, IsWeak, Dest, Ptr, Val1, Val2, Size,
SuccessOrder, FailureOrder);
return;
}
// Create all the relevant BB's
llvm::BasicBlock *MonotonicBB = nullptr, *AcquireBB = nullptr,
*SeqCstBB = nullptr;
MonotonicBB = CGF.createBasicBlock("monotonic_fail", CGF.CurFn);
if (SuccessOrder != llvm::Monotonic && SuccessOrder != llvm::Release)
AcquireBB = CGF.createBasicBlock("acquire_fail", CGF.CurFn);
if (SuccessOrder == llvm::SequentiallyConsistent)
SeqCstBB = CGF.createBasicBlock("seqcst_fail", CGF.CurFn);
llvm::BasicBlock *ContBB = CGF.createBasicBlock("atomic.continue", CGF.CurFn);
llvm::SwitchInst *SI = CGF.Builder.CreateSwitch(FailureOrderVal, MonotonicBB);
// Emit all the different atomics
// 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.
CGF.Builder.SetInsertPoint(MonotonicBB);
emitAtomicCmpXchg(CGF, E, IsWeak, Dest, Ptr, Val1, Val2,
Size, SuccessOrder, llvm::Monotonic);
CGF.Builder.CreateBr(ContBB);
if (AcquireBB) {
CGF.Builder.SetInsertPoint(AcquireBB);
emitAtomicCmpXchg(CGF, E, IsWeak, Dest, Ptr, Val1, Val2,
Size, SuccessOrder, llvm::Acquire);
CGF.Builder.CreateBr(ContBB);
SI->addCase(CGF.Builder.getInt32(AtomicExpr::AO_ABI_memory_order_consume),
AcquireBB);
SI->addCase(CGF.Builder.getInt32(AtomicExpr::AO_ABI_memory_order_acquire),
AcquireBB);
}
if (SeqCstBB) {
CGF.Builder.SetInsertPoint(SeqCstBB);
emitAtomicCmpXchg(CGF, E, IsWeak, Dest, Ptr, Val1, Val2,
Size, SuccessOrder, llvm::SequentiallyConsistent);
CGF.Builder.CreateBr(ContBB);
SI->addCase(CGF.Builder.getInt32(AtomicExpr::AO_ABI_memory_order_seq_cst),
SeqCstBB);
}
CGF.Builder.SetInsertPoint(ContBB);
}
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::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:
emitAtomicCmpXchgFailureSet(CGF, E, false, Dest, Ptr, Val1, Val2,
FailureOrder, Size, Order);
return;
case AtomicExpr::AO__c11_atomic_compare_exchange_weak:
emitAtomicCmpXchgFailureSet(CGF, E, true, Dest, Ptr, Val1, Val2,
FailureOrder, Size, Order);
return;
case AtomicExpr::AO__atomic_compare_exchange:
case AtomicExpr::AO__atomic_compare_exchange_n: {
if (llvm::ConstantInt *IsWeakC = dyn_cast<llvm::ConstantInt>(IsWeak)) {
emitAtomicCmpXchgFailureSet(CGF, E, IsWeakC->getZExtValue(), Dest, Ptr,
Val1, Val2, FailureOrder, Size, Order);
} 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);
CGF.Builder.CreateBr(ContBB);
CGF.Builder.SetInsertPoint(WeakBB);
emitAtomicCmpXchgFailureSet(CGF, E, true, Dest, Ptr, Val1, Val2,
FailureOrder, Size, Order);
CGF.Builder.CreateBr(ContBB);
CGF.Builder.SetInsertPoint(ContBB);
}
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->setVolatile(E->isVolatile());
CGF.Builder.CreateStore(Load, Dest);
return;
}
case AtomicExpr::AO__c11_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);
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; // the NOT is special cased below
// Fall through.
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);
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);
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
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<AtomicType>())
MemTy = AT->getValueType();
CharUnits sizeChars, alignChars;
std::tie(sizeChars, alignChars) = getContext().getTypeInfoInChars(AtomicTy);
uint64_t Size = sizeChars.getQuantity();
unsigned MaxInlineWidthInBits = getTarget().getMaxAtomicInlineWidth();
bool UseLibcall = (sizeChars != alignChars ||
getContext().toBits(sizeChars) > MaxInlineWidthInBits);
llvm::Value *IsWeak = nullptr, *OrderFail = nullptr;
Address Val1 = Address::invalid();
Address Val2 = Address::invalid();
Address Dest = Address::invalid();
Address Ptr(EmitScalarExpr(E->getPtr()), alignChars);
if (E->getOp() == AtomicExpr::AO__c11_atomic_init) {
LValue lvalue = MakeAddrLValue(Ptr, AtomicTy);
EmitAtomicInit(E->getVal1(), lvalue);
return RValue::get(nullptr);
}
llvm::Value *Order = EmitScalarExpr(E->getOrder());
switch (E->getOp()) {
case AtomicExpr::AO__c11_atomic_init:
llvm_unreachable("Already handled above with EmitAtomicInit!");
case AtomicExpr::AO__c11_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__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->getNumSubExprs() == 6)
IsWeak = 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));
auto Temp = CreateMemTemp(Val1Ty, ".atomictmp");
Val1 = Temp;
EmitStoreOfScalar(Val1Scalar, MakeAddrLValue(Temp, 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;
}
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);
Ptr = Atomics.emitCastToAtomicIntPointer(Ptr);
if (Val1.isValid()) Val1 = Atomics.convertToAtomicIntPointer(Val1);
if (Val2.isValid()) Val2 = Atomics.convertToAtomicIntPointer(Val2);
if (Dest.isValid())
Dest = Atomics.emitCastToAtomicIntPointer(Dest);
else if (E->isCmpXChg())
Dest = CreateMemTemp(RValTy, "cmpxchg.bool");
else if (!RValTy->isVoidType())
Dest = Atomics.emitCastToAtomicIntPointer(Atomics.CreateTempAlloca());
// 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:
llvm_unreachable("Already handled above with EmitAtomicInit!");
case AtomicExpr::AO__c11_atomic_fetch_add:
case AtomicExpr::AO__atomic_fetch_add:
case AtomicExpr::AO__c11_atomic_fetch_and:
case AtomicExpr::AO__atomic_fetch_and:
case AtomicExpr::AO__c11_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__atomic_fetch_sub:
case AtomicExpr::AO__c11_atomic_fetch_xor:
case AtomicExpr::AO__atomic_fetch_xor:
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:
// For these, only library calls for certain sizes exist.
UseOptimizedLibcall = true;
break;
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__atomic_load_n:
case AtomicExpr::AO__atomic_load:
case AtomicExpr::AO__atomic_store_n:
case AtomicExpr::AO__atomic_store:
case AtomicExpr::AO__atomic_exchange_n:
case AtomicExpr::AO__atomic_exchange:
case AtomicExpr::AO__atomic_compare_exchange_n:
case AtomicExpr::AO__atomic_compare_exchange:
// Only use optimized library calls for sizes for which they exist.
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
Args.add(RValue::get(EmitCastToVoidPtr(Ptr.getPointer())),
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;
switch (E->getOp()) {
case AtomicExpr::AO__c11_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__atomic_compare_exchange:
case AtomicExpr::AO__atomic_compare_exchange_n:
LibCallName = "__atomic_compare_exchange";
RetTy = getContext().BoolTy;
HaveRetTy = true;
Args.add(RValue::get(EmitCastToVoidPtr(Val1.getPointer())),
getContext().VoidPtrTy);
AddDirectArgument(*this, Args, UseOptimizedLibcall, Val2.getPointer(),
MemTy, E->getExprLoc(), sizeChars);
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__atomic_exchange_n:
case AtomicExpr::AO__atomic_exchange:
LibCallName = "__atomic_exchange";
AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(),
MemTy, E->getExprLoc(), sizeChars);
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__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(), sizeChars);
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__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;
// Fall through.
case AtomicExpr::AO__c11_atomic_fetch_add:
case AtomicExpr::AO__atomic_fetch_add:
LibCallName = "__atomic_fetch_add";
AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(),
LoweredMemTy, E->getExprLoc(), sizeChars);
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;
// Fall through.
case AtomicExpr::AO__c11_atomic_fetch_and:
case AtomicExpr::AO__atomic_fetch_and:
LibCallName = "__atomic_fetch_and";
AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(),
MemTy, E->getExprLoc(), sizeChars);
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;
// Fall through.
case AtomicExpr::AO__c11_atomic_fetch_or:
case AtomicExpr::AO__atomic_fetch_or:
LibCallName = "__atomic_fetch_or";
AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(),
MemTy, E->getExprLoc(), sizeChars);
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;
// Fall through.
case AtomicExpr::AO__c11_atomic_fetch_sub:
case AtomicExpr::AO__atomic_fetch_sub:
LibCallName = "__atomic_fetch_sub";
AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(),
LoweredMemTy, E->getExprLoc(), sizeChars);
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;
// Fall through.
case AtomicExpr::AO__c11_atomic_fetch_xor:
case AtomicExpr::AO__atomic_fetch_xor:
LibCallName = "__atomic_fetch_xor";
AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(),
MemTy, E->getExprLoc(), sizeChars);
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
// Fall through.
case AtomicExpr::AO__atomic_fetch_nand:
LibCallName = "__atomic_fetch_nand";
AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(),
MemTy, E->getExprLoc(), sizeChars);
break;
}
// 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(sizeChars), /*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);
// PostOp is only needed for the atomic_*_fetch operations, and
// thus is only needed for and implemented in the
// UseOptimizedLibcall codepath.
assert(UseOptimizedLibcall || !PostOp);
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 (PostOp) {
llvm::Value *LoadVal1 = Args[1].RV.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__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;
if (isa<llvm::ConstantInt>(Order)) {
int ord = cast<llvm::ConstantInt>(Order)->getZExtValue();
switch (ord) {
case AtomicExpr::AO_ABI_memory_order_relaxed:
EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail,
Size, llvm::Monotonic);
break;
case AtomicExpr::AO_ABI_memory_order_consume:
case AtomicExpr::AO_ABI_memory_order_acquire:
if (IsStore)
break; // Avoid crashing on code with undefined behavior
EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail,
Size, llvm::Acquire);
break;
case AtomicExpr::AO_ABI_memory_order_release:
if (IsLoad)
break; // Avoid crashing on code with undefined behavior
EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail,
Size, llvm::Release);
break;
case AtomicExpr::AO_ABI_memory_order_acq_rel:
if (IsLoad || IsStore)
break; // Avoid crashing on code with undefined behavior
EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail,
Size, llvm::AcquireRelease);
break;
case AtomicExpr::AO_ABI_memory_order_seq_cst:
EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail,
Size, llvm::SequentiallyConsistent);
break;
default: // invalid order
// We should not ever get here normally, but it's hard to
// enforce that in general.
break;
}
if (RValTy->isVoidType())
return RValue::get(nullptr);
return convertTempToRValue(
Builder.CreateBitCast(Dest, ConvertTypeForMem(RValTy)->getPointerTo()),
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::Monotonic);
Builder.CreateBr(ContBB);
if (!IsStore) {
Builder.SetInsertPoint(AcquireBB);
EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail,
Size, llvm::Acquire);
Builder.CreateBr(ContBB);
SI->addCase(Builder.getInt32(AtomicExpr::AO_ABI_memory_order_consume),
AcquireBB);
SI->addCase(Builder.getInt32(AtomicExpr::AO_ABI_memory_order_acquire),
AcquireBB);
}
if (!IsLoad) {
Builder.SetInsertPoint(ReleaseBB);
EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail,
Size, llvm::Release);
Builder.CreateBr(ContBB);
SI->addCase(Builder.getInt32(AtomicExpr::AO_ABI_memory_order_release),
ReleaseBB);
}
if (!IsLoad && !IsStore) {
Builder.SetInsertPoint(AcqRelBB);
EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail,
Size, llvm::AcquireRelease);
Builder.CreateBr(ContBB);
SI->addCase(Builder.getInt32(AtomicExpr::AO_ABI_memory_order_acq_rel),
AcqRelBB);
}
Builder.SetInsertPoint(SeqCstBB);
EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail,
Size, llvm::SequentiallyConsistent);
Builder.CreateBr(ContBB);
SI->addCase(Builder.getInt32(AtomicExpr::AO_ABI_memory_order_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()),
RValTy, E->getExprLoc());
}
Address AtomicInfo::emitCastToAtomicIntPointer(Address addr) const {
unsigned addrspace =
cast<llvm::PointerType>(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, CharUnits());
// 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.getAlignmentSource()));
if (LVal.isVectorElt())
return CGF.EmitLoadOfLValue(
LValue::MakeVectorElt(addr, LVal.getVectorIdx(), LVal.getType(),
LVal.getAlignmentSource()), loc);
assert(LVal.isExtVectorElt());
return CGF.EmitLoadOfExtVectorElementLValue(LValue::MakeExtVectorElt(
addr, LVal.getExtVectorElts(), LVal.getType(),
LVal.getAlignmentSource()));
}
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, translateAtomicOrdering(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);
if (LVal.getTBAAInfo())
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();
return IsVolatile && AtomicIsInline;
}
/// An type is a candidate for having its loads and stores be made atomic if
/// we are operating under /volatile:ms *and* we know the access is volatile and
/// performing such an operation can be performed without a libcall.
bool CodeGenFunction::typeIsSuitableForInlineAtomic(QualType Ty,
bool IsVolatile) const {
// An atomic is inline if we don't need to use a libcall (e.g. it is builtin).
bool AtomicIsInline = getContext().getTargetInfo().hasBuiltinAtomic(
getContext().getTypeSize(Ty), getContext().getTypeAlign(Ty));
return CGM.getCodeGenOpts().MSVolatile && IsVolatile && AtomicIsInline;
}
RValue CodeGenFunction::EmitAtomicLoad(LValue LV, SourceLocation SL,
AggValueSlot Slot) {
llvm::AtomicOrdering AO;
bool IsVolatile = LV.isVolatileQualified();
if (LV.getType()->isAtomicType()) {
AO = llvm::SequentiallyConsistent;
} else {
AO = llvm::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()) {
CGF.EmitAggregateCopy(getAtomicAddress(),
rvalue.getAggregateAddress(),
getAtomicType(),
(rvalue.isVolatileQualified()
|| LVal.isVolatileQualified()));
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();
}
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<llvm::IntegerType>(Value->getType()))
return CGF.EmitToMemory(Value, ValueTy);
else {
llvm::IntegerType *InputIntTy = llvm::IntegerType::get(
CGF.getLLVMContext(),
LVal.isSimple() ? getValueSizeInBits() : getAtomicSizeInBits());
if (isa<llvm::PointerType>(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<llvm::Value *, llvm::Value *> 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, translateAtomicOrdering(Success))),
CGF.getContext().IntTy);
Args.add(RValue::get(llvm::ConstantInt::get(
CGF.IntTy, translateAtomicOrdering(Failure))),
CGF.getContext().IntTy);
auto SuccessFailureRVal = emitAtomicLibcall(CGF, "__atomic_compare_exchange",
CGF.getContext().BoolTy, Args);
return SuccessFailureRVal.getScalarVal();
}
std::pair<RValue, llvm::Value *> AtomicInfo::EmitAtomicCompareExchange(
RValue Expected, RValue Desired, llvm::AtomicOrdering Success,
llvm::AtomicOrdering Failure, bool IsWeak) {
if (Failure >= Success)
// Don't assert on undefined behavior.
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<RValue(RValue)> &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.getAlignmentSource());
DesiredLVal =
LValue::MakeBitfield(DesiredAddr, AtomicLVal.getBitFieldInfo(),
AtomicLVal.getType(),
AtomicLVal.getAlignmentSource());
} else if (AtomicLVal.isVectorElt()) {
UpdateLVal = LValue::MakeVectorElt(Ptr, AtomicLVal.getVectorIdx(),
AtomicLVal.getType(),
AtomicLVal.getAlignmentSource());
DesiredLVal = LValue::MakeVectorElt(
DesiredAddr, AtomicLVal.getVectorIdx(), AtomicLVal.getType(),
AtomicLVal.getAlignmentSource());
} else {
assert(AtomicLVal.isExtVectorElt());
UpdateLVal = LValue::MakeExtVectorElt(Ptr, AtomicLVal.getExtVectorElts(),
AtomicLVal.getType(),
AtomicLVal.getAlignmentSource());
DesiredLVal = LValue::MakeExtVectorElt(
DesiredAddr, AtomicLVal.getExtVectorElts(), AtomicLVal.getType(),
AtomicLVal.getAlignmentSource());
}
UpdateLVal.setTBAAInfo(AtomicLVal.getTBAAInfo());
DesiredLVal.setTBAAInfo(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<RValue(RValue)> &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<RValue(RValue)> &UpdateOp,
bool IsVolatile) {
auto Failure = llvm::AtomicCmpXchgInst::getStrongestFailureOrdering(AO);
// Do the atomic load.
auto *OldVal = EmitAtomicLoadOp(AO, 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.getAlignmentSource());
} else if (AtomicLVal.isVectorElt()) {
DesiredLVal =
LValue::MakeVectorElt(DesiredAddr, AtomicLVal.getVectorIdx(),
AtomicLVal.getType(),
AtomicLVal.getAlignmentSource());
} else {
assert(AtomicLVal.isExtVectorElt());
DesiredLVal = LValue::MakeExtVectorElt(
DesiredAddr, AtomicLVal.getExtVectorElts(), AtomicLVal.getType(),
AtomicLVal.getAlignmentSource());
}
DesiredLVal.setTBAAInfo(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(AO, 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<RValue(RValue)> &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::SequentiallyConsistent;
} else {
AO = llvm::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().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, AtomicInfo::translateAtomicOrdering(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);
// Initializations don't need to be atomic.
if (!isInit)
store->setAtomic(AO);
// Other decoration.
if (IsVolatile)
store->setVolatile(true);
if (dest.getTBAAInfo())
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<RValue, llvm::Value *> 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().getElementType());
assert(!Desired.isAggregate() ||
Desired.getAggregateAddress().getElementType() ==
Obj.getAddress().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<RValue(RValue)> &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,
AggValueSlot::IsNotDestructed,
AggValueSlot::DoesNotNeedGCBarriers,
AggValueSlot::IsNotAliased,
Zeroed ? AggValueSlot::IsZeroed :
AggValueSlot::IsNotZeroed);
EmitAggExpr(init, slot);
return;
}
}
llvm_unreachable("bad evaluation kind");
}