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[Transforms][ASan] Move findAllocaForValue() to Utils/Local.cpp. NFC 

Summary:
Factor out findAllocaForValue() from ASan so that we can use it in
MSan to handle lifetime intrinsics.

Reviewers: eugenis, pcc

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D60615

llvm-svn: 358380
This commit is contained in:
Alexander Potapenko 2019-04-15 08:59:56 +00:00
parent f54328372b
commit 6a63e5aa7b
3 changed files with 45 additions and 39 deletions
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4
llvm/include/llvm/Transforms/Utils/Local.h
View File

@ -335,6 +335,10 @@ bool replaceDbgDeclareForAlloca(AllocaInst *AI, Value *NewAllocaAddress,
void replaceDbgValueForAlloca(AllocaInst *AI, Value *NewAllocaAddress,
DIBuilder &Builder, int Offset = 0);
/// Finds alloca where the value comes from.
AllocaInst *findAllocaForValue(Value *V,
DenseMap<Value *, AllocaInst *> &AllocaForValue);
/// Assuming the instruction \p I is going to be deleted, attempt to salvage
/// debug users of \p I by writing the effect of \p I in a DIExpression.
/// Returns true if any debug users were updated.

42
llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
View File

@ -1038,7 +1038,9 @@ struct FunctionStackPoisoner : public InstVisitor<FunctionStackPoisoner> {
!ConstantInt::isValueValidForType(IntptrTy, SizeValue))
return;
// Find alloca instruction that corresponds to llvm.lifetime argument.
AllocaInst *AI = findAllocaForValue(II.getArgOperand(1));
AllocaInst *AI =
llvm::findAllocaForValue(II.getArgOperand(1), AllocaForValue);
// We're interested only in allocas we can handle.
if (!AI || !ASan.isInterestingAlloca(*AI))
return;
bool DoPoison = (ID == Intrinsic::lifetime_end);
@ -1062,9 +1064,6 @@ struct FunctionStackPoisoner : public InstVisitor<FunctionStackPoisoner> {
// ---------------------- Helpers.
void initializeCallbacks(Module &M);
/// Finds alloca where the value comes from.
AllocaInst *findAllocaForValue(Value *V);
// Copies bytes from ShadowBytes into shadow memory for indexes where
// ShadowMask is not zero. If ShadowMask[i] is zero, we assume that
// ShadowBytes[i] is constantly zero and doesn't need to be overwritten.
@ -3228,41 +3227,6 @@ void FunctionStackPoisoner::poisonAlloca(Value *V, uint64_t Size,
// variable may go in and out of scope several times, e.g. in loops).
// (3) if we poisoned at least one %alloca in a function,
// unpoison the whole stack frame at function exit.
AllocaInst *FunctionStackPoisoner::findAllocaForValue(Value *V) {
if (AllocaInst *AI = dyn_cast<AllocaInst>(V))
// We're interested only in allocas we can handle.
return ASan.isInterestingAlloca(*AI) ? AI : nullptr;
// See if we've already calculated (or started to calculate) alloca for a
// given value.
AllocaForValueMapTy::iterator I = AllocaForValue.find(V);
if (I != AllocaForValue.end()) return I->second;
// Store 0 while we're calculating alloca for value V to avoid
// infinite recursion if the value references itself.
AllocaForValue[V] = nullptr;
AllocaInst *Res = nullptr;
if (CastInst *CI = dyn_cast<CastInst>(V))
Res = findAllocaForValue(CI->getOperand(0));
else if (PHINode *PN = dyn_cast<PHINode>(V)) {
for (Value *IncValue : PN->incoming_values()) {
// Allow self-referencing phi-nodes.
if (IncValue == PN) continue;
AllocaInst *IncValueAI = findAllocaForValue(IncValue);
// AI for incoming values should exist and should all be equal.
if (IncValueAI == nullptr || (Res != nullptr && IncValueAI != Res))
return nullptr;
Res = IncValueAI;
}
} else if (GetElementPtrInst *EP = dyn_cast<GetElementPtrInst>(V)) {
Res = findAllocaForValue(EP->getPointerOperand());
} else {
LLVM_DEBUG(dbgs() << "Alloca search canceled on unknown instruction: " << *V
<< "\n");
}
if (Res) AllocaForValue[V] = Res;
return Res;
}
void FunctionStackPoisoner::handleDynamicAllocaCall(AllocaInst *AI) {
IRBuilder<> IRB(AI);

38
llvm/lib/Transforms/Utils/Local.cpp
View File

@ -2886,3 +2886,41 @@ bool llvm::canReplaceOperandWithVariable(const Instruction *I, unsigned OpIdx) {
return true;
}
}
using AllocaForValueMapTy = DenseMap<Value *, AllocaInst *>;
AllocaInst *llvm::findAllocaForValue(Value *V,
AllocaForValueMapTy &AllocaForValue) {
if (AllocaInst *AI = dyn_cast<AllocaInst>(V))
return AI;
// See if we've already calculated (or started to calculate) alloca for a
// given value.
AllocaForValueMapTy::iterator I = AllocaForValue.find(V);
if (I != AllocaForValue.end())
return I->second;
// Store 0 while we're calculating alloca for value V to avoid
// infinite recursion if the value references itself.
AllocaForValue[V] = nullptr;
AllocaInst *Res = nullptr;
if (CastInst *CI = dyn_cast<CastInst>(V))
Res = findAllocaForValue(CI->getOperand(0), AllocaForValue);
else if (PHINode *PN = dyn_cast<PHINode>(V)) {
for (Value *IncValue : PN->incoming_values()) {
// Allow self-referencing phi-nodes.
if (IncValue == PN)
continue;
AllocaInst *IncValueAI = findAllocaForValue(IncValue, AllocaForValue);
// AI for incoming values should exist and should all be equal.
if (IncValueAI == nullptr || (Res != nullptr && IncValueAI != Res))
return nullptr;
Res = IncValueAI;
}
} else if (GetElementPtrInst *EP = dyn_cast<GetElementPtrInst>(V)) {
Res = findAllocaForValue(EP->getPointerOperand(), AllocaForValue);
} else {
LLVM_DEBUG(dbgs() << "Alloca search cancelled on unknown instruction: "
<< *V << "\n");
}
if (Res)
AllocaForValue[V] = Res;
return Res;
}