static const unsigned kMinOriginAlignment = 4;
static const unsigned kShadowTLSAlignment = 8;
+// These constants must be kept in sync with the ones in msan.h.
+static const unsigned kParamTLSSize = 800;
+static const unsigned kRetvalTLSSize = 800;
+
// Accesses sizes are powers of two: 1, 2, 4, 8.
static const size_t kNumberOfAccessSizes = 4;
cl::desc("Do not wrap indirect calls with target in the same module"),
cl::Hidden, cl::init(true));
+// This is an experiment to enable handling of cases where shadow is a non-zero
+// compile-time constant. For some unexplainable reason they were silently
+// ignored in the instrumentation.
+static cl::opt<bool> ClCheckConstantShadow("msan-check-constant-shadow",
+ cl::desc("Insert checks for constant shadow values"),
+ cl::Hidden, cl::init(false));
+
namespace {
/// \brief An instrumentation pass implementing detection of uninitialized
// Create globals.
RetvalTLS = new GlobalVariable(
- M, ArrayType::get(IRB.getInt64Ty(), 8), false,
+ M, ArrayType::get(IRB.getInt64Ty(), kRetvalTLSSize / 8), false,
GlobalVariable::ExternalLinkage, nullptr, "__msan_retval_tls", nullptr,
GlobalVariable::InitialExecTLSModel);
RetvalOriginTLS = new GlobalVariable(
"__msan_retval_origin_tls", nullptr, GlobalVariable::InitialExecTLSModel);
ParamTLS = new GlobalVariable(
- M, ArrayType::get(IRB.getInt64Ty(), 1000), false,
+ M, ArrayType::get(IRB.getInt64Ty(), kParamTLSSize / 8), false,
GlobalVariable::ExternalLinkage, nullptr, "__msan_param_tls", nullptr,
GlobalVariable::InitialExecTLSModel);
ParamOriginTLS = new GlobalVariable(
- M, ArrayType::get(OriginTy, 1000), false, GlobalVariable::ExternalLinkage,
- nullptr, "__msan_param_origin_tls", nullptr,
- GlobalVariable::InitialExecTLSModel);
+ M, ArrayType::get(OriginTy, kParamTLSSize / 4), false,
+ GlobalVariable::ExternalLinkage, nullptr, "__msan_param_origin_tls",
+ nullptr, GlobalVariable::InitialExecTLSModel);
VAArgTLS = new GlobalVariable(
- M, ArrayType::get(IRB.getInt64Ty(), 1000), false,
+ M, ArrayType::get(IRB.getInt64Ty(), kParamTLSSize / 8), false,
GlobalVariable::ExternalLinkage, nullptr, "__msan_va_arg_tls", nullptr,
GlobalVariable::InitialExecTLSModel);
VAArgOverflowSizeTLS = new GlobalVariable(
// The following flags disable parts of MSan instrumentation based on
// blacklist contents and command-line options.
bool InsertChecks;
- bool LoadShadow;
+ bool PropagateShadow;
bool PoisonStack;
bool PoisonUndef;
bool CheckReturnValue;
bool SanitizeFunction = F.getAttributes().hasAttribute(
AttributeSet::FunctionIndex, Attribute::SanitizeMemory);
InsertChecks = SanitizeFunction;
- LoadShadow = SanitizeFunction;
+ PropagateShadow = SanitizeFunction;
PoisonStack = SanitizeFunction && ClPoisonStack;
PoisonUndef = SanitizeFunction && ClPoisonUndef;
// FIXME: Consider using SpecialCaseList to specify a list of functions that
// TODO(eugenis): handle non-zero constant shadow by inserting an
// unconditional check (can not simply fail compilation as this could
// be in the dead code).
- if (isa<Constant>(ConvertedShadow)) return;
+ if (!ClCheckConstantShadow)
+ if (isa<Constant>(ConvertedShadow)) return;
unsigned TypeSizeInBits =
MS.DL->getTypeSizeInBits(ConvertedShadow->getType());
unsigned SizeIndex = TypeSizeToSizeIndex(TypeSizeInBits);
ConvertedShadow, IRB.getIntNTy(8 * (1 << SizeIndex)));
IRB.CreateCall3(Fn, ConvertedShadow2,
IRB.CreatePointerCast(Addr, IRB.getInt8PtrTy()),
- updateOrigin(Origin, IRB));
+ Origin);
} else {
Value *Cmp = IRB.CreateICmpNE(
ConvertedShadow, getCleanShadow(ConvertedShadow), "_mscmp");
DEBUG(dbgs() << " SHAD0 : " << *Shadow << "\n");
Value *ConvertedShadow = convertToShadowTyNoVec(Shadow, IRB);
DEBUG(dbgs() << " SHAD1 : " << *ConvertedShadow << "\n");
- // See the comment in materializeStores().
- if (isa<Constant>(ConvertedShadow)) return;
+ // See the comment in storeOrigin().
+ if (!ClCheckConstantShadow)
+ if (isa<Constant>(ConvertedShadow)) return;
unsigned TypeSizeInBits =
MS.DL->getTypeSizeInBits(ConvertedShadow->getType());
unsigned SizeIndex = TypeSizeToSizeIndex(TypeSizeInBits);
size_t NumValues = PN->getNumIncomingValues();
for (size_t v = 0; v < NumValues; v++) {
PNS->addIncoming(getShadow(PN, v), PN->getIncomingBlock(v));
- if (PNO)
- PNO->addIncoming(getOrigin(PN, v), PN->getIncomingBlock(v));
+ if (PNO) PNO->addIncoming(getOrigin(PN, v), PN->getIncomingBlock(v));
}
}
return VectorType::get(IntegerType::get(*MS.C, EltSize),
VT->getNumElements());
}
+ if (ArrayType *AT = dyn_cast<ArrayType>(OrigTy)) {
+ return ArrayType::get(getShadowTy(AT->getElementType()),
+ AT->getNumElements());
+ }
if (StructType *ST = dyn_cast<StructType>(OrigTy)) {
SmallVector<Type*, 4> Elements;
for (unsigned i = 0, n = ST->getNumElements(); i < n; i++)
/// \brief Set SV to be the shadow value for V.
void setShadow(Value *V, Value *SV) {
assert(!ShadowMap.count(V) && "Values may only have one shadow");
- ShadowMap[V] = SV;
+ ShadowMap[V] = PropagateShadow ? SV : getCleanShadow(V);
}
/// \brief Set Origin to be the origin value for V.
assert(ShadowTy);
if (isa<IntegerType>(ShadowTy) || isa<VectorType>(ShadowTy))
return Constant::getAllOnesValue(ShadowTy);
- StructType *ST = cast<StructType>(ShadowTy);
- SmallVector<Constant *, 4> Vals;
- for (unsigned i = 0, n = ST->getNumElements(); i < n; i++)
- Vals.push_back(getPoisonedShadow(ST->getElementType(i)));
- return ConstantStruct::get(ST, Vals);
+ if (ArrayType *AT = dyn_cast<ArrayType>(ShadowTy)) {
+ SmallVector<Constant *, 4> Vals(AT->getNumElements(),
+ getPoisonedShadow(AT->getElementType()));
+ return ConstantArray::get(AT, Vals);
+ }
+ if (StructType *ST = dyn_cast<StructType>(ShadowTy)) {
+ SmallVector<Constant *, 4> Vals;
+ for (unsigned i = 0, n = ST->getNumElements(); i < n; i++)
+ Vals.push_back(getPoisonedShadow(ST->getElementType(i)));
+ return ConstantStruct::get(ST, Vals);
+ }
+ llvm_unreachable("Unexpected shadow type");
}
/// \brief Create a dirty shadow for a given value.
/// This function either returns the value set earlier with setShadow,
/// or extracts if from ParamTLS (for function arguments).
Value *getShadow(Value *V) {
+ if (!PropagateShadow) return getCleanShadow(V);
if (Instruction *I = dyn_cast<Instruction>(V)) {
// For instructions the shadow is already stored in the map.
Value *Shadow = ShadowMap[V];
? MS.DL->getTypeAllocSize(FArg.getType()->getPointerElementType())
: MS.DL->getTypeAllocSize(FArg.getType());
if (A == &FArg) {
+ bool Overflow = ArgOffset + Size > kParamTLSSize;
Value *Base = getShadowPtrForArgument(&FArg, EntryIRB, ArgOffset);
if (FArg.hasByValAttr()) {
// ByVal pointer itself has clean shadow. We copy the actual
Type *EltType = A->getType()->getPointerElementType();
ArgAlign = MS.DL->getABITypeAlignment(EltType);
}
- unsigned CopyAlign = std::min(ArgAlign, kShadowTLSAlignment);
- Value *Cpy = EntryIRB.CreateMemCpy(
- getShadowPtr(V, EntryIRB.getInt8Ty(), EntryIRB), Base, Size,
- CopyAlign);
- DEBUG(dbgs() << " ByValCpy: " << *Cpy << "\n");
- (void)Cpy;
+ if (Overflow) {
+ // ParamTLS overflow.
+ EntryIRB.CreateMemSet(
+ getShadowPtr(V, EntryIRB.getInt8Ty(), EntryIRB),
+ Constant::getNullValue(EntryIRB.getInt8Ty()), Size, ArgAlign);
+ } else {
+ unsigned CopyAlign = std::min(ArgAlign, kShadowTLSAlignment);
+ Value *Cpy = EntryIRB.CreateMemCpy(
+ getShadowPtr(V, EntryIRB.getInt8Ty(), EntryIRB), Base, Size,
+ CopyAlign);
+ DEBUG(dbgs() << " ByValCpy: " << *Cpy << "\n");
+ (void)Cpy;
+ }
*ShadowPtr = getCleanShadow(V);
} else {
- *ShadowPtr = EntryIRB.CreateAlignedLoad(Base, kShadowTLSAlignment);
+ if (Overflow) {
+ // ParamTLS overflow.
+ *ShadowPtr = getCleanShadow(V);
+ } else {
+ *ShadowPtr =
+ EntryIRB.CreateAlignedLoad(Base, kShadowTLSAlignment);
+ }
}
DEBUG(dbgs() << " ARG: " << FArg << " ==> " <<
**ShadowPtr << "\n");
- if (MS.TrackOrigins) {
+ if (MS.TrackOrigins && !Overflow) {
Value *OriginPtr =
getOriginPtrForArgument(&FArg, EntryIRB, ArgOffset);
setOrigin(A, EntryIRB.CreateLoad(OriginPtr));
}
}
- ArgOffset += DataLayout::RoundUpAlignment(Size, kShadowTLSAlignment);
+ ArgOffset += RoundUpToAlignment(Size, kShadowTLSAlignment);
}
assert(*ShadowPtr && "Could not find shadow for an argument");
return *ShadowPtr;
/// UMR warning in runtime if the value is not fully defined.
void insertShadowCheck(Value *Val, Instruction *OrigIns) {
assert(Val);
- Instruction *Shadow = dyn_cast_or_null<Instruction>(getShadow(Val));
- if (!Shadow) return;
- Instruction *Origin = dyn_cast_or_null<Instruction>(getOrigin(Val));
+ Value *Shadow, *Origin;
+ if (ClCheckConstantShadow) {
+ Shadow = getShadow(Val);
+ if (!Shadow) return;
+ Origin = getOrigin(Val);
+ } else {
+ Shadow = dyn_cast_or_null<Instruction>(getShadow(Val));
+ if (!Shadow) return;
+ Origin = dyn_cast_or_null<Instruction>(getOrigin(Val));
+ }
insertShadowCheck(Shadow, Origin, OrigIns);
}
IRBuilder<> IRB(I.getNextNode());
Type *ShadowTy = getShadowTy(&I);
Value *Addr = I.getPointerOperand();
- if (LoadShadow) {
+ if (PropagateShadow) {
Value *ShadowPtr = getShadowPtr(Addr, ShadowTy, IRB);
setShadow(&I,
IRB.CreateAlignedLoad(ShadowPtr, I.getAlignment(), "_msld"));
I.setOrdering(addAcquireOrdering(I.getOrdering()));
if (MS.TrackOrigins) {
- if (LoadShadow) {
+ if (PropagateShadow) {
unsigned Alignment = std::max(kMinOriginAlignment, I.getAlignment());
setOrigin(&I,
IRB.CreateAlignedLoad(getOriginPtr(Addr, IRB), Alignment));
if (!Origin) {
Origin = OpOrigin;
} else {
- Value *FlatShadow = MSV->convertToShadowTyNoVec(OpShadow, IRB);
- Value *Cond = IRB.CreateICmpNE(FlatShadow,
- MSV->getCleanShadow(FlatShadow));
- Origin = IRB.CreateSelect(Cond, OpOrigin, Origin);
+ Constant *ConstOrigin = dyn_cast<Constant>(OpOrigin);
+ // No point in adding something that might result in 0 origin value.
+ if (!ConstOrigin || !ConstOrigin->isNullValue()) {
+ Value *FlatShadow = MSV->convertToShadowTyNoVec(OpShadow, IRB);
+ Value *Cond =
+ IRB.CreateICmpNE(FlatShadow, MSV->getCleanShadow(FlatShadow));
+ Origin = IRB.CreateSelect(Cond, OpOrigin, Origin);
+ }
}
}
return *this;
SC.Done(&I);
}
+ // \brief Handle multiplication by constant.
+ //
+ // Handle a special case of multiplication by constant that may have one or
+ // more zeros in the lower bits. This makes corresponding number of lower bits
+ // of the result zero as well. We model it by shifting the other operand
+ // shadow left by the required number of bits. Effectively, we transform
+ // (X * (A * 2**B)) to ((X << B) * A) and instrument (X << B) as (Sx << B).
+ // We use multiplication by 2**N instead of shift to cover the case of
+ // multiplication by 0, which may occur in some elements of a vector operand.
+ void handleMulByConstant(BinaryOperator &I, Constant *ConstArg,
+ Value *OtherArg) {
+ Constant *ShadowMul;
+ Type *Ty = ConstArg->getType();
+ if (Ty->isVectorTy()) {
+ unsigned NumElements = Ty->getVectorNumElements();
+ Type *EltTy = Ty->getSequentialElementType();
+ SmallVector<Constant *, 16> Elements;
+ for (unsigned Idx = 0; Idx < NumElements; ++Idx) {
+ ConstantInt *Elt =
+ dyn_cast<ConstantInt>(ConstArg->getAggregateElement(Idx));
+ APInt V = Elt->getValue();
+ APInt V2 = APInt(V.getBitWidth(), 1) << V.countTrailingZeros();
+ Elements.push_back(ConstantInt::get(EltTy, V2));
+ }
+ ShadowMul = ConstantVector::get(Elements);
+ } else {
+ ConstantInt *Elt = dyn_cast<ConstantInt>(ConstArg);
+ APInt V = Elt->getValue();
+ APInt V2 = APInt(V.getBitWidth(), 1) << V.countTrailingZeros();
+ ShadowMul = ConstantInt::get(Elt->getType(), V2);
+ }
+
+ IRBuilder<> IRB(&I);
+ setShadow(&I,
+ IRB.CreateMul(getShadow(OtherArg), ShadowMul, "msprop_mul_cst"));
+ setOrigin(&I, getOrigin(OtherArg));
+ }
+
+ void visitMul(BinaryOperator &I) {
+ Constant *constOp0 = dyn_cast<Constant>(I.getOperand(0));
+ Constant *constOp1 = dyn_cast<Constant>(I.getOperand(1));
+ if (constOp0 && !constOp1)
+ handleMulByConstant(I, constOp0, I.getOperand(1));
+ else if (constOp1 && !constOp0)
+ handleMulByConstant(I, constOp1, I.getOperand(0));
+ else
+ handleShadowOr(I);
+ }
+
void visitFAdd(BinaryOperator &I) { handleShadowOr(I); }
void visitFSub(BinaryOperator &I) { handleShadowOr(I); }
void visitFMul(BinaryOperator &I) { handleShadowOr(I); }
void visitAdd(BinaryOperator &I) { handleShadowOr(I); }
void visitSub(BinaryOperator &I) { handleShadowOr(I); }
void visitXor(BinaryOperator &I) { handleShadowOr(I); }
- void visitMul(BinaryOperator &I) { handleShadowOr(I); }
void handleDiv(Instruction &I) {
IRBuilder<> IRB(&I);
Value *Addr = I.getArgOperand(0);
Type *ShadowTy = getShadowTy(&I);
- if (LoadShadow) {
+ if (PropagateShadow) {
Value *ShadowPtr = getShadowPtr(Addr, ShadowTy, IRB);
// We don't know the pointer alignment (could be unaligned SSE load!).
// Have to assume to worst case.
insertShadowCheck(Addr, &I);
if (MS.TrackOrigins) {
- if (LoadShadow)
+ if (PropagateShadow)
setOrigin(&I, IRB.CreateLoad(getOriginPtr(Addr, IRB)));
else
setOrigin(&I, getCleanOrigin());
Value *Op = I.getArgOperand(0);
Type *OpType = Op->getType();
Function *BswapFunc = Intrinsic::getDeclaration(
- F.getParent(), Intrinsic::bswap, ArrayRef<Type*>(&OpType, 1));
+ F.getParent(), Intrinsic::bswap, makeArrayRef(&OpType, 1));
setShadow(&I, IRB.CreateCall(BswapFunc, getShadow(Op)));
setOrigin(&I, getOrigin(Op));
}
}
}
- // \brief Instrument vector shift instrinsic.
+ // \brief Instrument vector pack instrinsic.
//
// This function instruments intrinsics like x86_mmx_packsswb, that
- // packs elements of 2 input vectors into half as much bits with saturation.
+ // packs elements of 2 input vectors into half as many bits with saturation.
// Shadow is propagated with the signed variant of the same intrinsic applied
// to sext(Sa != zeroinitializer), sext(Sb != zeroinitializer).
// EltSizeInBits is used only for x86mmx arguments.
setOriginForNaryOp(I);
}
+ // \brief Instrument sum-of-absolute-differencies intrinsic.
+ void handleVectorSadIntrinsic(IntrinsicInst &I) {
+ const unsigned SignificantBitsPerResultElement = 16;
+ bool isX86_MMX = I.getOperand(0)->getType()->isX86_MMXTy();
+ Type *ResTy = isX86_MMX ? IntegerType::get(*MS.C, 64) : I.getType();
+ unsigned ZeroBitsPerResultElement =
+ ResTy->getScalarSizeInBits() - SignificantBitsPerResultElement;
+
+ IRBuilder<> IRB(&I);
+ Value *S = IRB.CreateOr(getShadow(&I, 0), getShadow(&I, 1));
+ S = IRB.CreateBitCast(S, ResTy);
+ S = IRB.CreateSExt(IRB.CreateICmpNE(S, Constant::getNullValue(ResTy)),
+ ResTy);
+ S = IRB.CreateLShr(S, ZeroBitsPerResultElement);
+ S = IRB.CreateBitCast(S, getShadowTy(&I));
+ setShadow(&I, S);
+ setOriginForNaryOp(I);
+ }
+
+ // \brief Instrument multiply-add intrinsic.
+ void handleVectorPmaddIntrinsic(IntrinsicInst &I,
+ unsigned EltSizeInBits = 0) {
+ bool isX86_MMX = I.getOperand(0)->getType()->isX86_MMXTy();
+ Type *ResTy = isX86_MMX ? getMMXVectorTy(EltSizeInBits * 2) : I.getType();
+ IRBuilder<> IRB(&I);
+ Value *S = IRB.CreateOr(getShadow(&I, 0), getShadow(&I, 1));
+ S = IRB.CreateBitCast(S, ResTy);
+ S = IRB.CreateSExt(IRB.CreateICmpNE(S, Constant::getNullValue(ResTy)),
+ ResTy);
+ S = IRB.CreateBitCast(S, getShadowTy(&I));
+ setShadow(&I, S);
+ setOriginForNaryOp(I);
+ }
+
void visitIntrinsicInst(IntrinsicInst &I) {
switch (I.getIntrinsicID()) {
case llvm::Intrinsic::bswap:
handleVectorPackIntrinsic(I, 32);
break;
+ case llvm::Intrinsic::x86_mmx_psad_bw:
+ case llvm::Intrinsic::x86_sse2_psad_bw:
+ case llvm::Intrinsic::x86_avx2_psad_bw:
+ handleVectorSadIntrinsic(I);
+ break;
+
+ case llvm::Intrinsic::x86_sse2_pmadd_wd:
+ case llvm::Intrinsic::x86_avx2_pmadd_wd:
+ case llvm::Intrinsic::x86_ssse3_pmadd_ub_sw_128:
+ case llvm::Intrinsic::x86_avx2_pmadd_ub_sw:
+ handleVectorPmaddIntrinsic(I);
+ break;
+
+ case llvm::Intrinsic::x86_ssse3_pmadd_ub_sw:
+ handleVectorPmaddIntrinsic(I, 8);
+ break;
+
+ case llvm::Intrinsic::x86_mmx_pmadd_wd:
+ handleVectorPmaddIntrinsic(I, 16);
+ break;
+
default:
if (!handleUnknownIntrinsic(I))
visitInstruction(I);
return;
}
- // Allow only tail calls with the same types, otherwise
- // we may have a false positive: shadow for a non-void RetVal
- // will get propagated to a void RetVal.
- if (Call->isTailCall() && Call->getType() != Call->getParent()->getType())
- Call->setTailCall(false);
-
assert(!isa<IntrinsicInst>(&I) && "intrinsics are handled elsewhere");
// We are going to insert code that relies on the fact that the callee
Value *ArgShadowBase = getShadowPtrForArgument(A, IRB, ArgOffset);
DEBUG(dbgs() << " Arg#" << i << ": " << *A <<
" Shadow: " << *ArgShadow << "\n");
+ bool ArgIsInitialized = false;
if (CS.paramHasAttr(i + 1, Attribute::ByVal)) {
assert(A->getType()->isPointerTy() &&
"ByVal argument is not a pointer!");
Size = MS.DL->getTypeAllocSize(A->getType()->getPointerElementType());
- unsigned Alignment = CS.getParamAlignment(i + 1);
+ if (ArgOffset + Size > kParamTLSSize) break;
+ unsigned ParamAlignment = CS.getParamAlignment(i + 1);
+ unsigned Alignment = std::min(ParamAlignment, kShadowTLSAlignment);
Store = IRB.CreateMemCpy(ArgShadowBase,
getShadowPtr(A, Type::getInt8Ty(*MS.C), IRB),
Size, Alignment);
} else {
Size = MS.DL->getTypeAllocSize(A->getType());
+ if (ArgOffset + Size > kParamTLSSize) break;
Store = IRB.CreateAlignedStore(ArgShadow, ArgShadowBase,
kShadowTLSAlignment);
+ Constant *Cst = dyn_cast<Constant>(ArgShadow);
+ if (Cst && Cst->isNullValue()) ArgIsInitialized = true;
}
- if (MS.TrackOrigins)
+ if (MS.TrackOrigins && !ArgIsInitialized)
IRB.CreateStore(getOrigin(A),
getOriginPtrForArgument(A, IRB, ArgOffset));
(void)Store;
assert(Size != 0 && Store != nullptr);
DEBUG(dbgs() << " Param:" << *Store << "\n");
- ArgOffset += DataLayout::RoundUpAlignment(Size, 8);
+ ArgOffset += RoundUpToAlignment(Size, 8);
}
DEBUG(dbgs() << " done with call args\n");
void visitPHINode(PHINode &I) {
IRBuilder<> IRB(&I);
+ if (!PropagateShadow) {
+ setShadow(&I, getCleanShadow(&I));
+ return;
+ }
+
ShadowPHINodes.push_back(&I);
setShadow(&I, IRB.CreatePHI(getShadowTy(&I), I.getNumIncomingValues(),
"_msphi_s"));
Type *RealTy = A->getType()->getPointerElementType();
uint64_t ArgSize = MS.DL->getTypeAllocSize(RealTy);
Value *Base = getShadowPtrForVAArgument(RealTy, IRB, OverflowOffset);
- OverflowOffset += DataLayout::RoundUpAlignment(ArgSize, 8);
+ OverflowOffset += RoundUpToAlignment(ArgSize, 8);
IRB.CreateMemCpy(Base, MSV.getShadowPtr(A, IRB.getInt8Ty(), IRB),
ArgSize, kShadowTLSAlignment);
} else {
case AK_Memory:
uint64_t ArgSize = MS.DL->getTypeAllocSize(A->getType());
Base = getShadowPtrForVAArgument(A->getType(), IRB, OverflowOffset);
- OverflowOffset += DataLayout::RoundUpAlignment(ArgSize, 8);
+ OverflowOffset += RoundUpToAlignment(ArgSize, 8);
}
IRB.CreateAlignedStore(MSV.getShadow(A), Base, kShadowTLSAlignment);
}
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