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//===--- Atomic.cpp - Codegen of atomic operations ------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "llvm/Frontend/Atomic/Atomic.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/IRBuilder.h"
#include <utility>
using namespace llvm;
bool AtomicInfo::shouldCastToInt(Type *ValTy, bool CmpXchg) {
if (ValTy->isFloatingPointTy())
return ValTy->isX86_FP80Ty() || CmpXchg;
return !ValTy->isIntegerTy() && !ValTy->isPointerTy();
}
Value *AtomicInfo::EmitAtomicLoadOp(AtomicOrdering AO, bool IsVolatile,
bool CmpXchg) {
Value *Ptr = getAtomicPointer();
Type *AtomicTy = Ty;
if (shouldCastToInt(Ty, CmpXchg))
AtomicTy = IntegerType::get(getLLVMContext(), AtomicSizeInBits);
LoadInst *Load =
Builder->CreateAlignedLoad(AtomicTy, Ptr, AtomicAlign, "atomic-load");
Load->setAtomic(AO);
if (IsVolatile)
Load->setVolatile(true);
decorateWithTBAA(Load);
return Load;
}
CallInst *AtomicInfo::EmitAtomicLibcall(StringRef fnName, Type *ResultType,
ArrayRef<Value *> Args) {
LLVMContext &ctx = Builder->getContext();
SmallVector<Type *, 6> ArgTys;
for (Value *Arg : Args)
ArgTys.push_back(Arg->getType());
FunctionType *FnType = FunctionType::get(ResultType, ArgTys, false);
Module *M = Builder->GetInsertBlock()->getModule();
// TODO: Use llvm::TargetLowering for Libcall ABI
AttrBuilder fnAttrBuilder(ctx);
fnAttrBuilder.addAttribute(Attribute::NoUnwind);
fnAttrBuilder.addAttribute(Attribute::WillReturn);
AttributeList fnAttrs =
AttributeList::get(ctx, AttributeList::FunctionIndex, fnAttrBuilder);
FunctionCallee LibcallFn = M->getOrInsertFunction(fnName, FnType, fnAttrs);
CallInst *Call = Builder->CreateCall(LibcallFn, Args);
return Call;
}
std::pair<Value *, Value *> AtomicInfo::EmitAtomicCompareExchangeLibcall(
Value *ExpectedVal, Value *DesiredVal, AtomicOrdering Success,
AtomicOrdering Failure) {
LLVMContext &ctx = getLLVMContext();
// __atomic_compare_exchange's expected and desired are passed by pointers
// FIXME: types
// TODO: Get from llvm::TargetMachine / clang::TargetInfo
// if clang shares this codegen in future
constexpr uint64_t IntBits = 32;
// bool __atomic_compare_exchange(size_t size, void *obj, void *expected,
// void *desired, int success, int failure);
Value *Args[6] = {
getAtomicSizeValue(),
getAtomicPointer(),
ExpectedVal,
DesiredVal,
Constant::getIntegerValue(IntegerType::get(ctx, IntBits),
APInt(IntBits, static_cast<uint64_t>(Success),
/*signed=*/true)),
Constant::getIntegerValue(IntegerType::get(ctx, IntBits),
APInt(IntBits, static_cast<uint64_t>(Failure),
/*signed=*/true)),
};
auto Result = EmitAtomicLibcall("__atomic_compare_exchange",
IntegerType::getInt1Ty(ctx), Args);
return std::make_pair(ExpectedVal, Result);
}
std::pair<Value *, Value *> AtomicInfo::EmitAtomicCompareExchangeOp(
Value *ExpectedVal, Value *DesiredVal, AtomicOrdering Success,
AtomicOrdering Failure, bool IsVolatile, bool IsWeak) {
// Do the atomic store.
Value *Addr = getAtomicAddressAsAtomicIntPointer();
auto *Inst = Builder->CreateAtomicCmpXchg(Addr, ExpectedVal, DesiredVal,
getAtomicAlignment(), Success,
Failure, SyncScope::System);
// Other decoration.
Inst->setVolatile(IsVolatile);
Inst->setWeak(IsWeak);
auto *PreviousVal = Builder->CreateExtractValue(Inst, /*Idxs=*/0);
auto *SuccessFailureVal = Builder->CreateExtractValue(Inst, /*Idxs=*/1);
return std::make_pair(PreviousVal, SuccessFailureVal);
}
std::pair<LoadInst *, AllocaInst *>
AtomicInfo::EmitAtomicLoadLibcall(AtomicOrdering AO) {
LLVMContext &Ctx = getLLVMContext();
Type *SizedIntTy = Type::getIntNTy(Ctx, getAtomicSizeInBits());
Type *ResultTy;
SmallVector<Value *, 6> Args;
AttributeList Attr;
Module *M = Builder->GetInsertBlock()->getModule();
const DataLayout &DL = M->getDataLayout();
Args.push_back(
ConstantInt::get(DL.getIntPtrType(Ctx), this->getAtomicSizeInBits() / 8));
Value *PtrVal = getAtomicPointer();
PtrVal = Builder->CreateAddrSpaceCast(PtrVal, PointerType::getUnqual(Ctx));
Args.push_back(PtrVal);
AllocaInst *AllocaResult =
CreateAlloca(Ty, getAtomicPointer()->getName() + "atomic.temp.load");
const Align AllocaAlignment = DL.getPrefTypeAlign(SizedIntTy);
AllocaResult->setAlignment(AllocaAlignment);
Args.push_back(AllocaResult);
Constant *OrderingVal =
ConstantInt::get(Type::getInt32Ty(Ctx), (int)toCABI(AO));
Args.push_back(OrderingVal);
ResultTy = Type::getVoidTy(Ctx);
SmallVector<Type *, 6> ArgTys;
for (Value *Arg : Args)
ArgTys.push_back(Arg->getType());
FunctionType *FnType = FunctionType::get(ResultTy, ArgTys, false);
FunctionCallee LibcallFn =
M->getOrInsertFunction("__atomic_load", FnType, Attr);
CallInst *Call = Builder->CreateCall(LibcallFn, Args);
Call->setAttributes(Attr);
return std::make_pair(
Builder->CreateAlignedLoad(Ty, AllocaResult, AllocaAlignment),
AllocaResult);
}
std::pair<Value *, Value *> AtomicInfo::EmitAtomicCompareExchange(
Value *ExpectedVal, Value *DesiredVal, AtomicOrdering Success,
AtomicOrdering Failure, bool IsVolatile, bool IsWeak) {
if (shouldUseLibcall())
return EmitAtomicCompareExchangeLibcall(ExpectedVal, DesiredVal, Success,
Failure);
auto Res = EmitAtomicCompareExchangeOp(ExpectedVal, DesiredVal, Success,
Failure, IsVolatile, IsWeak);
return Res;
}
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