//===--- 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)
.RoundUpToAlignment(lvalue.getAlignment()));
auto VoidPtrAddr = CGF.EmitCastToVoidPtr(lvalue.getBitFieldAddr());
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;
LVal = LValue::MakeBitfield(Addr, BFI, lvalue.getType(),
lvalue.getAlignment());
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.getExtVectorAddr()
->getType()
->getPointerElementType()
->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 *getAtomicAddress() const {
if (LVal.isSimple())
return LVal.getAddress();
else if (LVal.isBitField())
return LVal.getBitFieldAddr();
else if (LVal.isVectorElt())
return LVal.getVectorAddr();
assert(LVal.isExtVectorElt());
return LVal.getExtVectorAddr();
}
/// 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.
llvm::Value *emitCastToAtomicIntPointer(llvm::Value *addr) const;
/// Turn an atomic-layout object into an r-value.
RValue convertTempToRValue(llvm::Value *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());
llvm::Value *addr = getAtomicAddress();
if (hasPadding())
addr = CGF.Builder.CreateStructGEP(nullptr, addr, 0);
return LValue::MakeAddr(addr, getValueType(), LVal.getAlignment(),
CGF.getContext(), 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);
/// Materialize an atomic r-value in atomic-layout memory.
llvm::Value *materializeRValue(RValue rvalue) const;
/// \brief Translates LLVM atomic ordering to GNU atomic ordering for
/// libcalls.
static AtomicExpr::AtomicOrderingKind
translateAtomicOrdering(const llvm::AtomicOrdering AO);
private:
bool requiresMemSetZero(llvm::Type *type) const;
/// \brief Creates temp alloca for intermediate operations on atomic value.
llvm::Value *CreateTempAlloca() 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.
std::pair<RValue, llvm::Value *> EmitAtomicCompareExchangeLibcall(
RValue Expected, RValue DesiredAddr,
llvm::AtomicOrdering Success = llvm::SequentiallyConsistent,
llvm::AtomicOrdering Failure = llvm::SequentiallyConsistent);
/// \brief Emits atomic compare-and-exchange op as LLVM instruction.
std::pair<RValue, llvm::Value *> EmitAtomicCompareExchangeOp(
RValue Expected, RValue Desired,
llvm::AtomicOrdering Success = llvm::SequentiallyConsistent,
llvm::AtomicOrdering Failure = llvm::SequentiallyConsistent,
bool IsWeak = false);
};
}
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");
}
llvm::Value *AtomicInfo::CreateTempAlloca() const {
auto *TempAlloca = CGF.CreateMemTemp(
(LVal.isBitField() && ValueSizeInBits > AtomicSizeInBits) ? ValueTy
: AtomicTy,
"atomic-temp");
TempAlloca->setAlignment(getAtomicAlignment().getQuantity());
// 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.getAddress();
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,
llvm::Value *Dest, llvm::Value *Ptr,
llvm::Value *Val1, llvm::Value *Val2,
uint64_t Size, unsigned Align,
llvm::AtomicOrdering SuccessOrder,
llvm::AtomicOrdering FailureOrder) {
// Note that cmpxchg doesn't support weak cmpxchg, at least at the moment.
llvm::LoadInst *Expected = CGF.Builder.CreateLoad(Val1);
Expected->setAlignment(Align);
llvm::LoadInst *Desired = CGF.Builder.CreateLoad(Val2);
Desired->setAlignment(Align);
llvm::AtomicCmpXchgInst *Pair = CGF.Builder.CreateAtomicCmpXchg(
Ptr, 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.
llvm::StoreInst *StoreExpected = CGF.Builder.CreateStore(Old, Val1);
StoreExpected->setAlignment(Align);
// 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()));
return;
}
/// 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, llvm::Value *Dest,
llvm::Value *Ptr, llvm::Value *Val1,
llvm::Value *Val2,
llvm::Value *FailureOrderVal,
uint64_t Size, unsigned Align,
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, Align,
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, Align, SuccessOrder, llvm::Monotonic);
CGF.Builder.CreateBr(ContBB);
if (AcquireBB) {
CGF.Builder.SetInsertPoint(AcquireBB);
emitAtomicCmpXchg(CGF, E, IsWeak, Dest, Ptr, Val1, Val2,
Size, Align, 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, Align, 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, llvm::Value *Dest,
llvm::Value *Ptr, llvm::Value *Val1, llvm::Value *Val2,
llvm::Value *IsWeak, llvm::Value *FailureOrder,
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:
emitAtomicCmpXchgFailureSet(CGF, E, false, Dest, Ptr, Val1, Val2,
FailureOrder, Size, Align, Order);
return;
case AtomicExpr::AO__c11_atomic_compare_exchange_weak:
emitAtomicCmpXchgFailureSet(CGF, E, true, Dest, Ptr, Val1, Val2,
FailureOrder, Size, Align, 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, Align, 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, Align, Order);
CGF.Builder.CreateBr(ContBB);
CGF.Builder.SetInsertPoint(WeakBB);
emitAtomicCmpXchgFailureSet(CGF, E, true, Dest, Ptr, Val1, Val2,
FailureOrder, Size, Align, 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->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;
}
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.
unsigned Align = CGF.getContext().getTypeAlignInChars(ValTy).getQuantity();
int64_t SizeInBits = CGF.getContext().toBits(SizeInChars);
ValTy =
CGF.getContext().getIntTypeForBitwidth(SizeInBits, /*Signed=*/false);
llvm::Type *IPtrTy = llvm::IntegerType::get(CGF.getLLVMContext(),
SizeInBits)->getPointerTo();
Val = CGF.EmitLoadOfScalar(CGF.Builder.CreateBitCast(Val, IPtrTy), false,
Align, 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, 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 =
getTarget().getMaxAtomicInlineWidth();
bool UseLibcall = (Size != Align ||
getContext().toBits(sizeChars) > MaxInlineWidthInBits);
llvm::Value *IsWeak = nullptr, *OrderFail = nullptr, *Val1 = nullptr,
*Val2 = nullptr;
llvm::Value *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(nullptr);
}
llvm::Value *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());
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));
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;
}
QualType RValTy = E->getType().getUnqualifiedType();
auto GetDest = [&] {
if (!RValTy->isVoidType() && !Dest) {
Dest = CreateMemTemp(RValTy, ".atomicdst");
}
return Dest;
};
// Use a library call. See: http://gcc.gnu.org/wiki/Atomic/GCCMM/LIbrary .
if (UseLibcall) {
bool UseOptimizedLibcall = false;
switch (E->getOp()) {
case AtomicExpr::AO__c11_atomic_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__c11_atomic_fetch_sub:
case AtomicExpr::AO__atomic_fetch_sub:
case AtomicExpr::AO__c11_atomic_fetch_xor:
case AtomicExpr::AO__atomic_fetch_xor:
// For these, only library calls for certain sizes exist.
UseOptimizedLibcall = true;
break;
default:
// 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)), getContext().VoidPtrTy);
std::string LibCallName;
QualType LoweredMemTy =
MemTy->isPointerType() ? getContext().getIntPtrType() : MemTy;
QualType RetTy;
bool HaveRetTy = false;
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 *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)), getContext().VoidPtrTy);
AddDirectArgument(*this, Args, UseOptimizedLibcall, Val2, 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, 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, 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_fetch_add_N(T *mem, T val, int order)
case AtomicExpr::AO__c11_atomic_fetch_add:
case AtomicExpr::AO__atomic_fetch_add:
LibCallName = "__atomic_fetch_add";
AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1, LoweredMemTy,
E->getExprLoc(), sizeChars);
break;
// T __atomic_fetch_and_N(T *mem, T val, int order)
case AtomicExpr::AO__c11_atomic_fetch_and:
case AtomicExpr::AO__atomic_fetch_and:
LibCallName = "__atomic_fetch_and";
AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1, MemTy,
E->getExprLoc(), sizeChars);
break;
// T __atomic_fetch_or_N(T *mem, T val, int order)
case AtomicExpr::AO__c11_atomic_fetch_or:
case AtomicExpr::AO__atomic_fetch_or:
LibCallName = "__atomic_fetch_or";
AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1, MemTy,
E->getExprLoc(), sizeChars);
break;
// T __atomic_fetch_sub_N(T *mem, T val, int order)
case AtomicExpr::AO__c11_atomic_fetch_sub:
case AtomicExpr::AO__atomic_fetch_sub:
LibCallName = "__atomic_fetch_sub";
AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1, LoweredMemTy,
E->getExprLoc(), sizeChars);
break;
// T __atomic_fetch_xor_N(T *mem, T val, int order)
case AtomicExpr::AO__c11_atomic_fetch_xor:
case AtomicExpr::AO__atomic_fetch_xor:
LibCallName = "__atomic_fetch_xor";
AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1, MemTy,
E->getExprLoc(), sizeChars);
break;
default: return EmitUnsupportedRValue(E, "atomic library call");
}
// 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)), getContext().VoidPtrTy);
}
}
// order is always the last parameter
Args.add(RValue::get(Order),
getContext().IntTy);
RValue Res = emitAtomicLibcall(*this, LibCallName, RetTy, Args);
// The value is returned directly from the libcall.
if (HaveRetTy && !RetTy->isVoidType())
return Res;
// The value is returned via an explicit out param.
if (RetTy->isVoidType())
return RValue::get(nullptr);
// The value is returned directly for optimized libcalls but the caller is
// expected an out-param.
if (UseOptimizedLibcall) {
llvm::Value *ResVal = Res.getScalarVal();
llvm::StoreInst *StoreDest = Builder.CreateStore(
ResVal,
Builder.CreateBitCast(GetDest(), ResVal->getType()->getPointerTo()));
StoreDest->setAlignment(Align);
}
return convertTempToRValue(Dest, 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;
llvm::Type *ITy =
llvm::IntegerType::get(getLLVMContext(), Size * 8);
llvm::Value *OrigDest = GetDest();
Ptr = Builder.CreateBitCast(
Ptr, ITy->getPointerTo(Ptr->getType()->getPointerAddressSpace()));
if (Val1) Val1 = Builder.CreateBitCast(Val1, ITy->getPointerTo());
if (Val2) Val2 = Builder.CreateBitCast(Val2, ITy->getPointerTo());
if (Dest && !E->isCmpXChg())
Dest = Builder.CreateBitCast(Dest, ITy->getPointerTo());
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, Align, 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, Align, 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, Align, 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, Align, llvm::AcquireRelease);
break;
case AtomicExpr::AO_ABI_memory_order_seq_cst:
EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail,
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 (RValTy->isVoidType())
return RValue::get(nullptr);
return convertTempToRValue(OrigDest, 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, Align, llvm::Monotonic);
Builder.CreateBr(ContBB);
if (!IsStore) {
Builder.SetInsertPoint(AcquireBB);
EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail,
Size, Align, 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, Align, 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, Align, 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, Align, 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);
return convertTempToRValue(OrigDest, RValTy, E->getExprLoc());
}
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,
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(nullptr, addr, 0);
// Otherwise, just convert the temporary to an r-value using the
// normal conversion routine.
return CGF.convertTempToRValue(addr, getValueType(), loc);
}
if (!AsValue)
// Get RValue from temp memory as atomic for non-simple lvalues
return RValue::get(
CGF.Builder.CreateAlignedLoad(addr, AtomicAlign.getQuantity()));
if (LVal.isBitField())
return CGF.EmitLoadOfBitfieldLValue(LValue::MakeBitfield(
addr, LVal.getBitFieldInfo(), LVal.getType(), LVal.getAlignment()));
if (LVal.isVectorElt())
return CGF.EmitLoadOfLValue(LValue::MakeVectorElt(addr, LVal.getVectorIdx(),
LVal.getType(),
LVal.getAlignment()),
loc);
assert(LVal.isExtVectorElt());
return CGF.EmitLoadOfExtVectorElementLValue(LValue::MakeExtVectorElt(
addr, LVal.getExtVectorElts(), LVal.getType(), LVal.getAlignment()));
}
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.
llvm::Value *Temp;
bool TempIsVolatile = false;
CharUnits TempAlignment;
if (AsValue && getEvaluationKind() == TEK_Aggregate) {
assert(!ResultSlot.isIgnored());
Temp = ResultSlot.getAddr();
TempAlignment = getValueAlignment();
TempIsVolatile = ResultSlot.isVolatile();
} else {
Temp = CreateTempAlloca();
TempAlignment = getAtomicAlignment();
}
// Slam the integer into the temporary.
llvm::Value *CastTemp = emitCastToAtomicIntPointer(Temp);
CGF.Builder.CreateAlignedStore(IntVal, CastTemp, TempAlignment.getQuantity())
->setVolatile(TempIsVolatile);
return convertTempToRValue(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(getAtomicAddress())),
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.
llvm::Value *Addr = emitCastToAtomicIntPointer(getAtomicAddress());
llvm::LoadInst *Load = CGF.Builder.CreateLoad(Addr, "atomic-load");
Load->setAtomic(AO);
// Other decoration.
Load->setAlignment(getAtomicAlignment().getQuantity());
if (IsVolatile)
Load->setVolatile(true);
if (LVal.getTBAAInfo())
CGF.CGM.DecorateInstruction(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) {
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 CGM.getCodeGenOpts().MSVolatile && 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()) {
llvm::Value *TempAddr;
if (LVal.isSimple() && !ResultSlot.isIgnored()) {
assert(getEvaluationKind() == TEK_Aggregate);
TempAddr = ResultSlot.getAddr();
} else
TempAddr = CreateTempAlloca();
EmitAtomicLoadLibcall(TempAddr, AO, IsVolatile);
// Okay, turn that back into the original value or whole atomic (for
// non-simple lvalues) type.
return convertTempToRValue(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(nullptr, 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.getAggregateAddr(),
getAtomicType(),
(rvalue.isVolatileQualified()
|| LVal.isVolatileQualified()),
LVal.getAlignment());
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.
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.
LValue TempLV = CGF.MakeAddrLValue(CreateTempAlloca(), getAtomicType(),
getAtomicAlignment());
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.
llvm::Value *Addr = materializeRValue(RVal);
// Cast the temporary to the atomic int type and pull a value out.
Addr = emitCastToAtomicIntPointer(Addr);
return CGF.Builder.CreateAlignedLoad(Addr,
getAtomicAlignment().getQuantity());
}
std::pair<RValue, llvm::Value *> AtomicInfo::EmitAtomicCompareExchangeOp(
RValue Expected, RValue Desired, llvm::AtomicOrdering Success,
llvm::AtomicOrdering Failure, bool IsWeak) {
// Do the atomic store.
auto *ExpectedVal = convertRValueToInt(Expected);
auto *DesiredVal = convertRValueToInt(Desired);
auto *Addr = emitCastToAtomicIntPointer(getAtomicAddress());
auto *Inst = CGF.Builder.CreateAtomicCmpXchg(Addr, 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(
ConvertIntToValueOrAtomic(PreviousVal, AggValueSlot::ignored(),
SourceLocation(), /*AsValue=*/false),
SuccessFailureVal);
}
std::pair<RValue, llvm::Value *>
AtomicInfo::EmitAtomicCompareExchangeLibcall(RValue Expected, RValue Desired,
llvm::AtomicOrdering Success,
llvm::AtomicOrdering Failure) {
// bool __atomic_compare_exchange(size_t size, void *obj, void *expected,
// void *desired, int success, int failure);
auto *ExpectedAddr = materializeRValue(Expected);
auto *DesiredAddr = materializeRValue(Desired);
CallArgList Args;
Args.add(RValue::get(getAtomicSizeValue()), CGF.getContext().getSizeType());
Args.add(RValue::get(CGF.EmitCastToVoidPtr(getAtomicAddress())),
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 std::make_pair(
convertTempToRValue(ExpectedAddr, AggValueSlot::ignored(),
SourceLocation(), /*AsValue=*/false),
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.
return EmitAtomicCompareExchangeLibcall(Expected, Desired, Success,
Failure);
}
// If we've got a scalar value of the right size, try to avoid going
// through memory.
return EmitAtomicCompareExchangeOp(Expected, Desired, Success, Failure,
IsWeak);
}
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.getAggregateAddr()->getType()->getPointerElementType()
== dest.getAddress()->getType()->getPointerElementType());
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.
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(atomics.getAtomicAddress())),
getContext().VoidPtrTy);
args.add(RValue::get(EmitCastToVoidPtr(srcAddr)), 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.
llvm::Value *addr =
atomics.emitCastToAtomicIntPointer(atomics.getAtomicAddress());
intValue = Builder.CreateIntCast(
intValue, addr->getType()->getPointerElementType(), /*isSigned=*/false);
llvm::StoreInst *store = Builder.CreateStore(intValue, addr);
// Initializations don't need to be atomic.
if (!isInit)
store->setAtomic(AO);
// Other decoration.
store->setAlignment(dest.getAlignment().getQuantity());
if (IsVolatile)
store->setVolatile(true);
if (dest.getTBAAInfo())
CGM.DecorateInstruction(store, dest.getTBAAInfo());
return;
}
// Atomic load of prev value.
RValue OldRVal =
atomics.EmitAtomicLoad(AggValueSlot::ignored(), SourceLocation(),
/*AsValue=*/false, AO, IsVolatile);
// For non-simple lvalues perform compare-and-swap procedure.
auto *ContBB = createBasicBlock("atomic_cont");
auto *ExitBB = createBasicBlock("atomic_exit");
auto *CurBB = Builder.GetInsertBlock();
EmitBlock(ContBB);
llvm::PHINode *PHI = Builder.CreatePHI(OldRVal.getScalarVal()->getType(),
/*NumReservedValues=*/2);
PHI->addIncoming(OldRVal.getScalarVal(), CurBB);
RValue OriginalRValue = RValue::get(PHI);
// Build new lvalue for temp address
auto *Ptr = atomics.materializeRValue(OriginalRValue);
// Build new lvalue for temp address
LValue UpdateLVal;
if (LVal.isBitField())
UpdateLVal = LValue::MakeBitfield(Ptr, LVal.getBitFieldInfo(),
LVal.getType(), LVal.getAlignment());
else if (LVal.isVectorElt())
UpdateLVal = LValue::MakeVectorElt(Ptr, LVal.getVectorIdx(), LVal.getType(),
LVal.getAlignment());
else {
assert(LVal.isExtVectorElt());
UpdateLVal = LValue::MakeExtVectorElt(Ptr, LVal.getExtVectorElts(),
LVal.getType(), LVal.getAlignment());
}
UpdateLVal.setTBAAInfo(LVal.getTBAAInfo());
// Store new value in the corresponding memory area
EmitStoreThroughLValue(rvalue, UpdateLVal);
// Load new value
RValue NewRValue = RValue::get(EmitLoadOfScalar(
Ptr, LVal.isVolatile(), atomics.getAtomicAlignment().getQuantity(),
atomics.getAtomicType(), SourceLocation()));
// Try to write new value using cmpxchg operation
auto Pair = atomics.EmitAtomicCompareExchange(OriginalRValue, NewRValue, AO);
PHI->addIncoming(Pair.first.getScalarVal(), ContBB);
Builder.CreateCondBr(Pair.second, ExitBB, ContBB);
EmitBlock(ExitBB, /*IsFinished=*/true);
}
/// 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.getAggregateAddr()->getType()->getPointerElementType() ==
Obj.getAddress()->getType()->getPointerElementType());
assert(!Desired.isAggregate() ||
Desired.getAggregateAddr()->getType()->getPointerElementType() ==
Obj.getAddress()->getType()->getPointerElementType());
AtomicInfo Atomics(*this, Obj);
return Atomics.EmitAtomicCompareExchange(Expected, Desired, Success, Failure,
IsWeak);
}
void CodeGenFunction::EmitAtomicUpdate(
LValue LVal, llvm::AtomicOrdering AO,
const std::function<RValue(RValue)> &UpdateOp, bool IsVolatile) {
AtomicInfo Atomics(*this, LVal);
LValue AtomicLVal = Atomics.getAtomicLValue();
// Atomic load of prev value.
RValue OldRVal =
Atomics.EmitAtomicLoad(AggValueSlot::ignored(), SourceLocation(),
/*AsValue=*/false, AO, IsVolatile);
bool IsScalar = OldRVal.isScalar();
auto *OldVal =
IsScalar ? OldRVal.getScalarVal() : Atomics.convertRValueToInt(OldRVal);
// For non-simple lvalues perform compare-and-swap procedure.
auto *ContBB = createBasicBlock("atomic_cont");
auto *ExitBB = createBasicBlock("atomic_exit");
auto *CurBB = Builder.GetInsertBlock();
EmitBlock(ContBB);
llvm::PHINode *PHI = Builder.CreatePHI(OldVal->getType(),
/*NumReservedValues=*/2);
PHI->addIncoming(OldVal, CurBB);
RValue OriginalRValue =
IsScalar ? RValue::get(PHI) : Atomics.ConvertIntToValueOrAtomic(
PHI, AggValueSlot::ignored(),
SourceLocation(), /*AsValue=*/false);
// Build new lvalue for temp address
LValue UpdateLVal;
llvm::Value *Ptr = nullptr;
RValue UpRVal;
if (AtomicLVal.isSimple()) {
UpRVal = OriginalRValue;
} else {
// Build new lvalue for temp address
Ptr = Atomics.materializeRValue(OriginalRValue);
if (AtomicLVal.isBitField())
UpdateLVal =
LValue::MakeBitfield(Ptr, AtomicLVal.getBitFieldInfo(),
AtomicLVal.getType(), AtomicLVal.getAlignment());
else if (AtomicLVal.isVectorElt())
UpdateLVal = LValue::MakeVectorElt(Ptr, AtomicLVal.getVectorIdx(),
AtomicLVal.getType(),
AtomicLVal.getAlignment());
else {
assert(AtomicLVal.isExtVectorElt());
UpdateLVal = LValue::MakeExtVectorElt(Ptr, AtomicLVal.getExtVectorElts(),
AtomicLVal.getType(),
AtomicLVal.getAlignment());
}
UpdateLVal.setTBAAInfo(LVal.getTBAAInfo());
UpRVal = EmitLoadOfLValue(UpdateLVal, SourceLocation());
}
// Store new value in the corresponding memory area
RValue NewRVal = UpdateOp(UpRVal);
if (!AtomicLVal.isSimple()) {
EmitStoreThroughLValue(NewRVal, UpdateLVal);
// Load new value
NewRVal = RValue::get(
EmitLoadOfScalar(Ptr, AtomicLVal.isVolatile(),
Atomics.getAtomicAlignment().getQuantity(),
Atomics.getAtomicType(), SourceLocation()));
}
// Try to write new value using cmpxchg operation
auto Pair = Atomics.EmitAtomicCompareExchange(OriginalRValue, NewRVal, AO);
OldVal = IsScalar ? Pair.first.getScalarVal()
: Atomics.convertRValueToInt(Pair.first);
PHI->addIncoming(OldVal, ContBB);
Builder.CreateCondBr(Pair.second, ExitBB, ContBB);
EmitBlock(ExitBB, /*IsFinished=*/true);
}
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");
}