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[NFC] [MSAN] disambiguate insertShadowCheck #146616

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merged 4 commits into from
Jul 8, 2025
Merged

[NFC] [MSAN] disambiguate insertShadowCheck #146616

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[𝘀𝗽𝗿] initial version
fmayer Jul 2, 2025
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fmayer Jul 2, 2025
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fmayer Jul 7, 2025
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fmayer Jul 8, 2025
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85 changes: 43 additions & 42 deletions llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2180,7 +2180,7 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
///
/// This location will be later instrumented with a check that will print a
/// UMR warning in runtime if the shadow value is not 0.
void insertShadowCheck(Value *Shadow, Value *Origin, Instruction *OrigIns) {
void insertCheckShadow(Value *Shadow, Value *Origin, Instruction *OrigIns) {
assert(Shadow);
if (!InsertChecks)
return;
Expand All @@ -2201,11 +2201,12 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
ShadowOriginAndInsertPoint(Shadow, Origin, OrigIns));
}

/// Remember the place where a shadow check should be inserted.
/// Get shadow for value, and remember the place where a shadow check should
/// be inserted.
///
/// This location will be later instrumented with a check that will print a
/// UMR warning in runtime if the value is not fully defined.
void insertShadowCheck(Value *Val, Instruction *OrigIns) {
void insertCheckShadowOf(Value *Val, Instruction *OrigIns) {
assert(Val);
Value *Shadow, *Origin;
if (ClCheckConstantShadow) {
Expand All @@ -2219,7 +2220,7 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
return;
Origin = dyn_cast_or_null<Instruction>(getOrigin(Val));
}
insertShadowCheck(Shadow, Origin, OrigIns);
insertCheckShadow(Shadow, Origin, OrigIns);
}

AtomicOrdering addReleaseOrdering(AtomicOrdering a) {
Expand Down Expand Up @@ -2331,7 +2332,7 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
}

if (ClCheckAccessAddress)
insertShadowCheck(I.getPointerOperand(), &I);
insertCheckShadowOf(I.getPointerOperand(), &I);

if (I.isAtomic())
I.setOrdering(addAcquireOrdering(I.getOrdering()));
Expand All @@ -2354,7 +2355,7 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
void visitStoreInst(StoreInst &I) {
StoreList.push_back(&I);
if (ClCheckAccessAddress)
insertShadowCheck(I.getPointerOperand(), &I);
insertCheckShadowOf(I.getPointerOperand(), &I);
}

void handleCASOrRMW(Instruction &I) {
Expand All @@ -2368,13 +2369,13 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
.first;

if (ClCheckAccessAddress)
insertShadowCheck(Addr, &I);
insertCheckShadowOf(Addr, &I);

// Only test the conditional argument of cmpxchg instruction.
// The other argument can potentially be uninitialized, but we can not
// detect this situation reliably without possible false positives.
if (isa<AtomicCmpXchgInst>(I))
insertShadowCheck(Val, &I);
insertCheckShadowOf(Val, &I);

IRB.CreateStore(getCleanShadow(Val), ShadowPtr);

Expand All @@ -2394,15 +2395,15 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {

// Vector manipulation.
void visitExtractElementInst(ExtractElementInst &I) {
insertShadowCheck(I.getOperand(1), &I);
insertCheckShadowOf(I.getOperand(1), &I);
IRBuilder<> IRB(&I);
setShadow(&I, IRB.CreateExtractElement(getShadow(&I, 0), I.getOperand(1),
"_msprop"));
setOrigin(&I, getOrigin(&I, 0));
}

void visitInsertElementInst(InsertElementInst &I) {
insertShadowCheck(I.getOperand(2), &I);
insertCheckShadowOf(I.getOperand(2), &I);
IRBuilder<> IRB(&I);
auto *Shadow0 = getShadow(&I, 0);
auto *Shadow1 = getShadow(&I, 1);
Expand Down Expand Up @@ -2884,7 +2885,7 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
void handleIntegerDiv(Instruction &I) {
IRBuilder<> IRB(&I);
// Strict on the second argument.
insertShadowCheck(I.getOperand(1), &I);
insertCheckShadowOf(I.getOperand(1), &I);
setShadow(&I, getShadow(&I, 0));
setOrigin(&I, getOrigin(&I, 0));
}
Expand Down Expand Up @@ -3162,7 +3163,7 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
IRB.CreateAlignedStore(Shadow, ShadowPtr, Align(1));

if (ClCheckAccessAddress)
insertShadowCheck(Addr, &I);
insertCheckShadowOf(Addr, &I);

// FIXME: factor out common code from materializeStores
if (MS.TrackOrigins)
Expand Down Expand Up @@ -3195,7 +3196,7 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
}

if (ClCheckAccessAddress)
insertShadowCheck(Addr, &I);
insertCheckShadowOf(Addr, &I);

if (MS.TrackOrigins) {
if (PropagateShadow)
Expand Down Expand Up @@ -3519,7 +3520,7 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
AggShadow = ConvertShadow;
}
assert(AggShadow->getType()->isIntegerTy());
insertShadowCheck(AggShadow, getOrigin(ConvertOp), &I);
insertCheckShadow(AggShadow, getOrigin(ConvertOp), &I);

// Build result shadow by zero-filling parts of CopyOp shadow that come from
// ConvertOp.
Expand Down Expand Up @@ -3926,7 +3927,7 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
IRB.CreateStore(getCleanShadow(Ty), ShadowPtr);

if (ClCheckAccessAddress)
insertShadowCheck(Addr, &I);
insertCheckShadowOf(Addr, &I);
}

void handleLdmxcsr(IntrinsicInst &I) {
Expand All @@ -3942,12 +3943,12 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
getShadowOriginPtr(Addr, IRB, Ty, Alignment, /*isStore*/ false);

if (ClCheckAccessAddress)
insertShadowCheck(Addr, &I);
insertCheckShadowOf(Addr, &I);

Value *Shadow = IRB.CreateAlignedLoad(Ty, ShadowPtr, Alignment, "_ldmxcsr");
Value *Origin = MS.TrackOrigins ? IRB.CreateLoad(MS.OriginTy, OriginPtr)
: getCleanOrigin();
insertShadowCheck(Shadow, Origin, &I);
insertCheckShadow(Shadow, Origin, &I);
}

void handleMaskedExpandLoad(IntrinsicInst &I) {
Expand All @@ -3958,8 +3959,8 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
Value *PassThru = I.getArgOperand(2);

if (ClCheckAccessAddress) {
insertShadowCheck(Ptr, &I);
insertShadowCheck(Mask, &I);
insertCheckShadowOf(Ptr, &I);
insertCheckShadowOf(Mask, &I);
}

if (!PropagateShadow) {
Expand Down Expand Up @@ -3991,8 +3992,8 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
Value *Mask = I.getArgOperand(2);

if (ClCheckAccessAddress) {
insertShadowCheck(Ptr, &I);
insertShadowCheck(Mask, &I);
insertCheckShadowOf(Ptr, &I);
insertCheckShadowOf(Mask, &I);
}

Value *Shadow = getShadow(Values);
Expand All @@ -4016,11 +4017,11 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {

Type *PtrsShadowTy = getShadowTy(Ptrs);
if (ClCheckAccessAddress) {
insertShadowCheck(Mask, &I);
insertCheckShadowOf(Mask, &I);
Value *MaskedPtrShadow = IRB.CreateSelect(
Mask, getShadow(Ptrs), Constant::getNullValue((PtrsShadowTy)),
"_msmaskedptrs");
insertShadowCheck(MaskedPtrShadow, getOrigin(Ptrs), &I);
insertCheckShadow(MaskedPtrShadow, getOrigin(Ptrs), &I);
}

if (!PropagateShadow) {
Expand Down Expand Up @@ -4054,11 +4055,11 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {

Type *PtrsShadowTy = getShadowTy(Ptrs);
if (ClCheckAccessAddress) {
insertShadowCheck(Mask, &I);
insertCheckShadowOf(Mask, &I);
Value *MaskedPtrShadow = IRB.CreateSelect(
Mask, getShadow(Ptrs), Constant::getNullValue((PtrsShadowTy)),
"_msmaskedptrs");
insertShadowCheck(MaskedPtrShadow, getOrigin(Ptrs), &I);
insertCheckShadow(MaskedPtrShadow, getOrigin(Ptrs), &I);
}

Value *Shadow = getShadow(Values);
Expand Down Expand Up @@ -4086,8 +4087,8 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
Value *Shadow = getShadow(V);

if (ClCheckAccessAddress) {
insertShadowCheck(Ptr, &I);
insertShadowCheck(Mask, &I);
insertCheckShadowOf(Ptr, &I);
insertCheckShadowOf(Mask, &I);
}

Value *ShadowPtr;
Expand Down Expand Up @@ -4119,8 +4120,8 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
Value *PassThru = I.getArgOperand(3);

if (ClCheckAccessAddress) {
insertShadowCheck(Ptr, &I);
insertShadowCheck(Mask, &I);
insertCheckShadowOf(Ptr, &I);
insertCheckShadowOf(Mask, &I);
}

if (!PropagateShadow) {
Expand Down Expand Up @@ -4183,8 +4184,8 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
Value *SrcShadow = getShadow(Src);

if (ClCheckAccessAddress) {
insertShadowCheck(Dst, &I);
insertShadowCheck(Mask, &I);
insertCheckShadowOf(Dst, &I);
insertCheckShadowOf(Mask, &I);
}

Value *DstShadowPtr;
Expand Down Expand Up @@ -4244,7 +4245,7 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
const Align Alignment = Align(1);

if (ClCheckAccessAddress) {
insertShadowCheck(Mask, &I);
insertCheckShadowOf(Mask, &I);
}

Type *SrcShadowTy = getShadowTy(Src);
Expand Down Expand Up @@ -4289,7 +4290,7 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
assert(V->getType() == IndexBits->getType());
V = IRB.CreateOr(V, IRB.CreateAnd(V, IndexBits));
}
insertShadowCheck(V, getOrigin(Idx), I);
insertCheckShadow(V, getOrigin(Idx), I);
}

// Instrument AVX permutation intrinsic.
Expand Down Expand Up @@ -4578,8 +4579,8 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
// Technically, we could probably just check whether the LSB is
// initialized, but intuitively it feels like a partly uninitialized mask
// is unintended, and we should warn the user immediately.
insertShadowCheck(Mask, &I);
insertShadowCheck(RoundingMode, &I);
insertCheckShadowOf(Mask, &I);
insertCheckShadowOf(RoundingMode, &I);

assert(isa<FixedVectorType>(A->getType()));
unsigned NumElements =
Expand Down Expand Up @@ -4660,7 +4661,7 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
ShadowArgs.push_back(LaneNumber);

// TODO: blend shadow of lane number into output shadow?
insertShadowCheck(LaneNumber, &I);
insertCheckShadowOf(LaneNumber, &I);
}

Value *Src = I.getArgOperand(numArgs - 1);
Expand Down Expand Up @@ -4712,7 +4713,7 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
int skipTrailingOperands = 1;

if (ClCheckAccessAddress)
insertShadowCheck(Addr, &I);
insertCheckShadowOf(Addr, &I);

// Second-last operand is the lane number (for vst{2,3,4}lane)
if (useLane) {
Expand Down Expand Up @@ -5687,7 +5688,7 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
if (A->getType()->isScalableTy()) {
LLVM_DEBUG(dbgs() << "Arg " << i << " is vscale: " << CB << "\n");
// Handle as noundef, but don't reserve tls slots.
insertShadowCheck(A, &CB);
insertCheckShadowOf(A, &CB);
continue;
}

Expand All @@ -5699,7 +5700,7 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
bool EagerCheck = MayCheckCall && !ByVal && NoUndef;

if (EagerCheck) {
insertShadowCheck(A, &CB);
insertCheckShadowOf(A, &CB);
Size = DL.getTypeAllocSize(A->getType());
} else {
[[maybe_unused]] Value *Store = nullptr;
Expand Down Expand Up @@ -5847,7 +5848,7 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
Value *Shadow = getShadow(RetVal);
bool StoreOrigin = true;
if (EagerCheck) {
insertShadowCheck(RetVal, &I);
insertCheckShadowOf(RetVal, &I);
Shadow = getCleanShadow(RetVal);
StoreOrigin = false;
}
Expand Down Expand Up @@ -6080,7 +6081,7 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
// Each such pointer is instrumented with a call to the runtime library.
Type *OpType = Operand->getType();
// Check the operand value itself.
insertShadowCheck(Operand, &I);
insertCheckShadowOf(Operand, &I);
if (!OpType->isPointerTy() || !isOutput) {
assert(!isOutput);
return;
Expand Down Expand Up @@ -6190,7 +6191,7 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
for (size_t i = 0, n = I.getNumOperands(); i < n; i++) {
Value *Operand = I.getOperand(i);
if (Operand->getType()->isSized())
insertShadowCheck(Operand, &I);
insertCheckShadowOf(Operand, &I);
}
setShadow(&I, getCleanShadow(&I));
setOrigin(&I, getCleanOrigin());
Expand Down
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