/// This file is a part of MemorySanitizer, a detector of uninitialized
/// reads.
///
-/// Status: early prototype.
-///
/// The algorithm of the tool is similar to Memcheck
/// (http://goo.gl/QKbem). We associate a few shadow bits with every
/// byte of the application memory, poison the shadow of the malloc-ed
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/Local.h"
#include "llvm/Transforms/Utils/ModuleUtils.h"
-#include "llvm/Transforms/Utils/SpecialCaseList.h"
using namespace llvm;
cl::desc("print out instructions with default strict semantics"),
cl::Hidden, cl::init(false));
-static cl::opt<std::string> ClBlacklistFile("msan-blacklist",
- cl::desc("File containing the list of functions where MemorySanitizer "
- "should not report bugs"), cl::Hidden);
-
static cl::opt<int> ClInstrumentationWithCallThreshold(
"msan-instrumentation-with-call-threshold",
cl::desc(
/// uninitialized reads.
class MemorySanitizer : public FunctionPass {
public:
- MemorySanitizer(int TrackOrigins = 0,
- StringRef BlacklistFile = StringRef())
+ MemorySanitizer(int TrackOrigins = 0)
: FunctionPass(ID),
TrackOrigins(std::max(TrackOrigins, (int)ClTrackOrigins)),
DL(nullptr),
WarningFn(nullptr),
- BlacklistFile(BlacklistFile.empty() ? ClBlacklistFile : BlacklistFile),
WrapIndirectCalls(!ClWrapIndirectCalls.empty()) {}
const char *getPassName() const override { return "MemorySanitizer"; }
bool runOnFunction(Function &F) override;
MDNode *ColdCallWeights;
/// \brief Branch weights for origin store.
MDNode *OriginStoreWeights;
- /// \brief Path to blacklist file.
- SmallString<64> BlacklistFile;
- /// \brief The blacklist.
- std::unique_ptr<SpecialCaseList> BL;
/// \brief An empty volatile inline asm that prevents callback merge.
InlineAsm *EmptyAsm;
"MemorySanitizer: detects uninitialized reads.",
false, false)
-FunctionPass *llvm::createMemorySanitizerPass(int TrackOrigins,
- StringRef BlacklistFile) {
- return new MemorySanitizer(TrackOrigins, BlacklistFile);
+FunctionPass *llvm::createMemorySanitizerPass(int TrackOrigins) {
+ return new MemorySanitizer(TrackOrigins);
}
/// \brief Create a non-const global initialized with the given string.
report_fatal_error("data layout missing");
DL = &DLP->getDataLayout();
- BL.reset(SpecialCaseList::createOrDie(BlacklistFile));
C = &(M.getContext());
unsigned PtrSize = DL->getPointerSizeInBits(/* AddressSpace */0);
switch (PtrSize) {
// 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;
MemorySanitizerVisitor(Function &F, MemorySanitizer &MS)
: F(F), MS(MS), VAHelper(CreateVarArgHelper(F, MS, *this)) {
- bool SanitizeFunction = !MS.BL->isIn(F) && F.getAttributes().hasAttribute(
- AttributeSet::FunctionIndex,
- Attribute::SanitizeMemory);
+ 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
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");
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));
}
}
/// \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.
/// 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];
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());
setOriginForNaryOp(I);
}
+ // \brief Get an X86_MMX-sized vector type.
+ Type *getMMXVectorTy(unsigned EltSizeInBits) {
+ const unsigned X86_MMXSizeInBits = 64;
+ return VectorType::get(IntegerType::get(*MS.C, EltSizeInBits),
+ X86_MMXSizeInBits / EltSizeInBits);
+ }
+
+ // \brief Returns a signed counterpart for an (un)signed-saturate-and-pack
+ // intrinsic.
+ Intrinsic::ID getSignedPackIntrinsic(Intrinsic::ID id) {
+ switch (id) {
+ case llvm::Intrinsic::x86_sse2_packsswb_128:
+ case llvm::Intrinsic::x86_sse2_packuswb_128:
+ return llvm::Intrinsic::x86_sse2_packsswb_128;
+
+ case llvm::Intrinsic::x86_sse2_packssdw_128:
+ case llvm::Intrinsic::x86_sse41_packusdw:
+ return llvm::Intrinsic::x86_sse2_packssdw_128;
+
+ case llvm::Intrinsic::x86_avx2_packsswb:
+ case llvm::Intrinsic::x86_avx2_packuswb:
+ return llvm::Intrinsic::x86_avx2_packsswb;
+
+ case llvm::Intrinsic::x86_avx2_packssdw:
+ case llvm::Intrinsic::x86_avx2_packusdw:
+ return llvm::Intrinsic::x86_avx2_packssdw;
+
+ case llvm::Intrinsic::x86_mmx_packsswb:
+ case llvm::Intrinsic::x86_mmx_packuswb:
+ return llvm::Intrinsic::x86_mmx_packsswb;
+
+ case llvm::Intrinsic::x86_mmx_packssdw:
+ return llvm::Intrinsic::x86_mmx_packssdw;
+ default:
+ llvm_unreachable("unexpected intrinsic id");
+ }
+ }
+
+ // \brief Instrument vector pack instrinsic.
+ //
+ // This function instruments intrinsics like x86_mmx_packsswb, that
+ // 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.
+ void handleVectorPackIntrinsic(IntrinsicInst &I, unsigned EltSizeInBits = 0) {
+ assert(I.getNumArgOperands() == 2);
+ bool isX86_MMX = I.getOperand(0)->getType()->isX86_MMXTy();
+ IRBuilder<> IRB(&I);
+ Value *S1 = getShadow(&I, 0);
+ Value *S2 = getShadow(&I, 1);
+ assert(isX86_MMX || S1->getType()->isVectorTy());
+
+ // SExt and ICmpNE below must apply to individual elements of input vectors.
+ // In case of x86mmx arguments, cast them to appropriate vector types and
+ // back.
+ Type *T = isX86_MMX ? getMMXVectorTy(EltSizeInBits) : S1->getType();
+ if (isX86_MMX) {
+ S1 = IRB.CreateBitCast(S1, T);
+ S2 = IRB.CreateBitCast(S2, T);
+ }
+ Value *S1_ext = IRB.CreateSExt(
+ IRB.CreateICmpNE(S1, llvm::Constant::getNullValue(T)), T);
+ Value *S2_ext = IRB.CreateSExt(
+ IRB.CreateICmpNE(S2, llvm::Constant::getNullValue(T)), T);
+ if (isX86_MMX) {
+ Type *X86_MMXTy = Type::getX86_MMXTy(*MS.C);
+ S1_ext = IRB.CreateBitCast(S1_ext, X86_MMXTy);
+ S2_ext = IRB.CreateBitCast(S2_ext, X86_MMXTy);
+ }
+
+ Function *ShadowFn = Intrinsic::getDeclaration(
+ F.getParent(), getSignedPackIntrinsic(I.getIntrinsicID()));
+
+ Value *S = IRB.CreateCall2(ShadowFn, S1_ext, S2_ext, "_msprop_vector_pack");
+ if (isX86_MMX) S = IRB.CreateBitCast(S, getShadowTy(&I));
+ setShadow(&I, S);
+ 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:
// case llvm::Intrinsic::x86_sse2_psll_dq_bs:
// case llvm::Intrinsic::x86_sse2_psrl_dq_bs:
+ case llvm::Intrinsic::x86_sse2_packsswb_128:
+ case llvm::Intrinsic::x86_sse2_packssdw_128:
+ case llvm::Intrinsic::x86_sse2_packuswb_128:
+ case llvm::Intrinsic::x86_sse41_packusdw:
+ case llvm::Intrinsic::x86_avx2_packsswb:
+ case llvm::Intrinsic::x86_avx2_packssdw:
+ case llvm::Intrinsic::x86_avx2_packuswb:
+ case llvm::Intrinsic::x86_avx2_packusdw:
+ handleVectorPackIntrinsic(I);
+ break;
+
+ case llvm::Intrinsic::x86_mmx_packsswb:
+ case llvm::Intrinsic::x86_mmx_packuswb:
+ handleVectorPackIntrinsic(I, 16);
+ break;
+
+ case llvm::Intrinsic::x86_mmx_packssdw:
+ 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
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"));
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