/// 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) {
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;
PoisonStack = SanitizeFunction && ClPoisonStack;
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);
setOriginForNaryOp(I);
}
- // \brief Instrument vector shift instrinsic.
+ // \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 much bits with saturation.
- // Shadow is propagated with the same intrinsic applied to
- // sext(Sa != zeroinitializer), sext(Sb != zeroinitializer).
- void handleVectorPackIntrinsic(IntrinsicInst &I) {
+ // 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);
- Type *T = S1->getType();
+ 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);
- Value *S = IRB.CreateCall2(I.getCalledValue(), S1_ext, S2_ext,
- "_msprop_vector_pack");
+ 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);
}
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_packssdw:
case llvm::Intrinsic::x86_mmx_packuswb:
- handleVectorPackIntrinsic(I);
+ 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:
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