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

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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).



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169859 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evgeniy Stepanov 2012-12-11 12:34:09 +00:00
parent 34525f9ac0
commit 7fa2240485
1 changed files with 13 additions and 8 deletions
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21
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);