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[msan][NFCI] Generalize handleIntrinsicByApplyingToShadow to allow alternative intrinsic for shadows #124831

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merged 2 commits into from
Jan 28, 2025
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[msan][NFCI] Generalize handleIntrinsicByApplyingToShadow to allow alternative intrinsic for shadows #124831

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[msan] Generalize handleIntrinsicByApplyingToShadow to allow alternat…
thurstond Jan 28, 2025
e15c1f1
Make shadowIntrinsicID mandatory
thurstond Jan 28, 2025
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15 changes: 12 additions & 3 deletions llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -4049,7 +4049,9 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
// consider this an acceptable tradeoff for performance.
// To make shadow propagation precise, we want the equivalent of
// "horizontal OR", but this is not available.
return handleIntrinsicByApplyingToShadow(I, /* trailingVerbatimArgs */ 0);
return handleIntrinsicByApplyingToShadow(
I, /*shadowIntrinsicID=*/I.getIntrinsicID(),
/*trailingVerbatimArgs*/ 0);
}

/// Handle Arm NEON vector store intrinsics (vst{2,3,4}, vst1x_{2,3,4},
Expand Down Expand Up @@ -4156,6 +4158,10 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
/// shadow[out] =
/// intrinsic(shadow[var1], shadow[var2], opType) | shadow[opType]
///
/// Typically, shadowIntrinsicID will be specified by the caller to be
/// I.getIntrinsicID(), but the caller can choose to replace it with another
/// intrinsic of the same type.
///
/// CAUTION: this assumes that the intrinsic will handle arbitrary
/// bit-patterns (for example, if the intrinsic accepts floats for
/// var1, we require that it doesn't care if inputs are NaNs).
Expand All @@ -4165,6 +4171,7 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
///
/// The origin is approximated using setOriginForNaryOp.
void handleIntrinsicByApplyingToShadow(IntrinsicInst &I,
Intrinsic::ID shadowIntrinsicID,
unsigned int trailingVerbatimArgs) {
IRBuilder<> IRB(&I);

Expand All @@ -4188,7 +4195,7 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
}

CallInst *CI =
IRB.CreateIntrinsic(I.getType(), I.getIntrinsicID(), ShadowArgs);
IRB.CreateIntrinsic(I.getType(), shadowIntrinsicID, ShadowArgs);
Value *CombinedShadow = CI;

// Combine the computed shadow with the shadow of trailing args
Expand Down Expand Up @@ -4664,7 +4671,9 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
case Intrinsic::aarch64_neon_tbx3:
case Intrinsic::aarch64_neon_tbx4: {
// The last trailing argument (index register) should be handled verbatim
handleIntrinsicByApplyingToShadow(I, 1);
handleIntrinsicByApplyingToShadow(
I, /*shadowIntrinsicID=*/I.getIntrinsicID(),
/*trailingVerbatimArgs*/ 1);
break;
}

Expand Down