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(
// 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);
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);
? 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));
/// 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);
}
assert(A->getType()->isPointerTy() &&
"ByVal argument is not a pointer!");
Size = MS.DL->getTypeAllocSize(A->getType()->getPointerElementType());
+ if (ArgOffset + Size > kParamTLSSize) break;
unsigned ParamAlignment = CS.getParamAlignment(i + 1);
unsigned Alignment = std::min(ParamAlignment, kShadowTLSAlignment);
Store = IRB.CreateMemCpy(ArgShadowBase,
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);