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[msan] Generalize handleIntrinsicByApplyingToShadow by adding bitcasting #123474

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merged 2 commits into from
Jan 23, 2025
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[msan] Generalize handleIntrinsicByApplyingToShadow by adding bitcasting #123474

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9d64d8b
[msan] Generalize handleIntrinsicByApplyingToShadow by adding bitcasting
thurstond Jan 18, 2025
f5d688c
Fix comment wording
thurstond Jan 18, 2025
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12 changes: 10 additions & 2 deletions llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -4008,6 +4008,10 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
/// shadow[out] =
/// intrinsic(shadow[var1], shadow[var2], opType) | shadow[opType]
///
/// 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).
///
/// For example, this can be applied to the Arm NEON vector table intrinsics
/// (tbl{1,2,3,4}).
///
Expand All @@ -4022,7 +4026,11 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
// Don't use getNumOperands() because it includes the callee
for (unsigned int i = 0; i < I.arg_size() - trailingVerbatimArgs; i++) {
Value *Shadow = getShadow(&I, i);
ShadowArgs.push_back(Shadow);

// Shadows are integer-ish types but some intrinsics require a
// different (e.g., floating-point) type.
ShadowArgs.push_back(
IRB.CreateBitCast(Shadow, I.getArgOperand(i)->getType()));
}

for (unsigned int i = I.arg_size() - trailingVerbatimArgs; i < I.arg_size();
Expand All @@ -4043,7 +4051,7 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
CombinedShadow = IRB.CreateOr(Shadow, CombinedShadow, "_msprop");
}

setShadow(&I, CombinedShadow);
setShadow(&I, IRB.CreateBitCast(CombinedShadow, getShadowTy(&I)));

setOriginForNaryOp(I);
}
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