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[msan] Use explicitely aligned stores and loads with function argument shadow. 

Use explicitely aligned store and load instructions to deal with argument and
retval shadow. This matters when an argument's alignment is higher than
__msan_param_tls alignment (which is the case with __m128i).

llvm-svn: 169859
This commit is contained in:
Evgeniy Stepanov 2012-12-11 12:34:09 +00:00
parent c5033786ba
commit d2bd319adc
1 changed files with 13 additions and 8 deletions
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21
llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
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@ -76,6 +76,7 @@ static const uint64_t kShadowMask32 = 1ULL << 31;
static const uint64_t kShadowMask64 = 1ULL << 46;
static const uint64_t kOriginOffset32 = 1ULL << 30;
static const uint64_t kOriginOffset64 = 1ULL << 45;
static const uint64_t kShadowTLSAlignment = 8;
// This is an important flag that makes the reports much more
// informative at the cost of greater slowdown. Not fully implemented
@ -1226,11 +1227,13 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
Size, Alignment);
} else {
Size = MS.TD->getTypeAllocSize(A->getType());
Store = IRB.CreateStore(ArgShadow, ArgShadowBase);
Store = IRB.CreateAlignedStore(ArgShadow, ArgShadowBase,
kShadowTLSAlignment);
}
if (ClTrackOrigins)
IRB.CreateStore(getOrigin(A),
getOriginPtrForArgument(A, IRB, ArgOffset));
IRB.CreateAlignedStore(getOrigin(A),
getOriginPtrForArgument(A, IRB, ArgOffset),
kShadowTLSAlignment);
assert(Size != 0 && Store != 0);
DEBUG(dbgs() << " Param:" << *Store << "\n");
ArgOffset += DataLayout::RoundUpAlignment(Size, 8);
@ -1248,7 +1251,7 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
IRBuilder<> IRBBefore(&I);
// Untill we have full dynamic coverage, make sure the retval shadow is 0.
Value *Base = getShadowPtrForRetval(&I, IRBBefore);
IRBBefore.CreateStore(getCleanShadow(&I), Base);
IRBBefore.CreateAlignedStore(getCleanShadow(&I), Base, kShadowTLSAlignment);
Instruction *NextInsn = 0;
if (CS.isCall()) {
NextInsn = I.getNextNode();
@ -1267,8 +1270,10 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
"Could not find insertion point for retval shadow load");
}
IRBuilder<> IRBAfter(NextInsn);
setShadow(&I, IRBAfter.CreateLoad(getShadowPtrForRetval(&I, IRBAfter),
"_msret"));
Value *RetvalShadow =
IRBAfter.CreateAlignedLoad(getShadowPtrForRetval(&I, IRBAfter),
kShadowTLSAlignment, "_msret");
setShadow(&I, RetvalShadow);
if (ClTrackOrigins)
setOrigin(&I, IRBAfter.CreateLoad(getOriginPtrForRetval(IRBAfter)));
}
@ -1280,7 +1285,7 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
Value *Shadow = getShadow(RetVal);
Value *ShadowPtr = getShadowPtrForRetval(RetVal, IRB);
DEBUG(dbgs() << "Return: " << *Shadow << "\n" << *ShadowPtr << "\n");
IRB.CreateStore(Shadow, ShadowPtr);
IRB.CreateAlignedStore(Shadow, ShadowPtr, kShadowTLSAlignment);
if (ClTrackOrigins)
IRB.CreateStore(getOrigin(RetVal), getOriginPtrForRetval(IRB));
}
@ -1471,7 +1476,7 @@ struct VarArgAMD64Helper : public VarArgHelper {
Base = getShadowPtrForVAArgument(A, IRB, OverflowOffset);
OverflowOffset += DataLayout::RoundUpAlignment(ArgSize, 8);
}
IRB.CreateStore(MSV.getShadow(A), Base);
IRB.CreateAlignedStore(MSV.getShadow(A), Base, kShadowTLSAlignment);
}
Constant *OverflowSize =
ConstantInt::get(IRB.getInt64Ty(), OverflowOffset - AMD64FpEndOffset);