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[msan] Avoid extra origin address realignment.

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Do not realign origin address if the corresponding application
address is at least 4-byte-aligned.

Saves 2.5% code size in track-origins mode.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223464 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evgeniy Stepanov
2014-12-05 14:34:03 +00:00
parent 54529ed1c4
commit c4c08aab64
2 changed files with 97 additions and 21 deletions
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45
lib/Transforms/Instrumentation/MemorySanitizer.cpp
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@ -522,9 +522,11 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
void storeOrigin(IRBuilder<> &IRB, Value *Addr, Value *Shadow, Value *Origin,
unsigned Alignment, bool AsCall) {
unsigned OriginAlignment = std::max(kMinOriginAlignment, Alignment);
if (isa<StructType>(Shadow->getType())) {
IRB.CreateAlignedStore(updateOrigin(Origin, IRB), getOriginPtr(Addr, IRB),
Alignment);
IRB.CreateAlignedStore(updateOrigin(Origin, IRB),
getOriginPtr(Addr, IRB, Alignment),
OriginAlignment);
} else {
Value *ConvertedShadow = convertToShadowTyNoVec(Shadow, IRB);
// TODO(eugenis): handle non-zero constant shadow by inserting an
@ -549,7 +551,8 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
Cmp, IRB.GetInsertPoint(), false, MS.OriginStoreWeights);
IRBuilder<> IRBNew(CheckTerm);
IRBNew.CreateAlignedStore(updateOrigin(Origin, IRBNew),
getOriginPtr(Addr, IRBNew), Alignment);
getOriginPtr(Addr, IRBNew, Alignment),
OriginAlignment);
}
}
}
@ -573,11 +576,9 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
if (SI.isAtomic()) SI.setOrdering(addReleaseOrdering(SI.getOrdering()));
if (MS.TrackOrigins) {
unsigned Alignment = std::max(kMinOriginAlignment, SI.getAlignment());
storeOrigin(IRB, Addr, Shadow, getOrigin(Val), Alignment,
if (MS.TrackOrigins)
storeOrigin(IRB, Addr, Shadow, getOrigin(Val), SI.getAlignment(),
InstrumentWithCalls);
}
}
}
@ -739,16 +740,17 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
/// address.
///
/// OriginAddr = (ShadowAddr + OriginOffset) & ~3ULL
Value *getOriginPtr(Value *Addr, IRBuilder<> &IRB) {
Value *getOriginPtr(Value *Addr, IRBuilder<> &IRB, unsigned Alignment) {
Value *ShadowLong =
IRB.CreateAnd(IRB.CreatePointerCast(Addr, MS.IntptrTy),
ConstantInt::get(MS.IntptrTy, ~MS.ShadowMask));
Value *Add =
IRB.CreateAdd(ShadowLong,
ConstantInt::get(MS.IntptrTy, MS.OriginOffset));
Value *SecondAnd =
IRB.CreateAnd(Add, ConstantInt::get(MS.IntptrTy, ~3ULL));
return IRB.CreateIntToPtr(SecondAnd, PointerType::get(IRB.getInt32Ty(), 0));
IRB.CreateAnd(IRB.CreatePointerCast(Addr, MS.IntptrTy),
ConstantInt::get(MS.IntptrTy, ~MS.ShadowMask));
Value *Origin = IRB.CreateAdd(
ShadowLong, ConstantInt::get(MS.IntptrTy, MS.OriginOffset));
if (Alignment < kMinOriginAlignment) {
uint64_t Mask = kMinOriginAlignment - 1;
Origin = IRB.CreateAnd(Origin, ConstantInt::get(MS.IntptrTy, ~Mask));
}
return IRB.CreateIntToPtr(Origin, PointerType::get(IRB.getInt32Ty(), 0));
}
/// \brief Compute the shadow address for a given function argument.
@ -1052,9 +1054,10 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
if (MS.TrackOrigins) {
if (PropagateShadow) {
unsigned Alignment = std::max(kMinOriginAlignment, I.getAlignment());
setOrigin(&I,
IRB.CreateAlignedLoad(getOriginPtr(Addr, IRB), Alignment));
unsigned Alignment = I.getAlignment();
unsigned OriginAlignment = std::max(kMinOriginAlignment, Alignment);
setOrigin(&I, IRB.CreateAlignedLoad(getOriginPtr(Addr, IRB, Alignment),
OriginAlignment));
} else {
setOrigin(&I, getCleanOrigin());
}
@ -1706,7 +1709,7 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
// FIXME: use ClStoreCleanOrigin
// FIXME: factor out common code from materializeStores
if (MS.TrackOrigins)
IRB.CreateStore(getOrigin(&I, 1), getOriginPtr(Addr, IRB));
IRB.CreateStore(getOrigin(&I, 1), getOriginPtr(Addr, IRB, 1));
return true;
}
@ -1733,7 +1736,7 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
if (MS.TrackOrigins) {
if (PropagateShadow)
setOrigin(&I, IRB.CreateLoad(getOriginPtr(Addr, IRB)));
setOrigin(&I, IRB.CreateLoad(getOriginPtr(Addr, IRB, 1)));
else
setOrigin(&I, getCleanOrigin());
}