| //===-- MemorySanitizer.cpp - detector of uninitialized reads -------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| /// \file |
| /// 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 |
| /// or alloca-ed memory, load the shadow bits on every memory read, |
| /// propagate the shadow bits through some of the arithmetic |
| /// instruction (including MOV), store the shadow bits on every memory |
| /// write, report a bug on some other instructions (e.g. JMP) if the |
| /// associated shadow is poisoned. |
| /// |
| /// But there are differences too. The first and the major one: |
| /// compiler instrumentation instead of binary instrumentation. This |
| /// gives us much better register allocation, possible compiler |
| /// optimizations and a fast start-up. But this brings the major issue |
| /// as well: msan needs to see all program events, including system |
| /// calls and reads/writes in system libraries, so we either need to |
| /// compile *everything* with msan or use a binary translation |
| /// component (e.g. DynamoRIO) to instrument pre-built libraries. |
| /// Another difference from Memcheck is that we use 8 shadow bits per |
| /// byte of application memory and use a direct shadow mapping. This |
| /// greatly simplifies the instrumentation code and avoids races on |
| /// shadow updates (Memcheck is single-threaded so races are not a |
| /// concern there. Memcheck uses 2 shadow bits per byte with a slow |
| /// path storage that uses 8 bits per byte). |
| /// |
| /// The default value of shadow is 0, which means "clean" (not poisoned). |
| /// |
| /// Every module initializer should call __msan_init to ensure that the |
| /// shadow memory is ready. On error, __msan_warning is called. Since |
| /// parameters and return values may be passed via registers, we have a |
| /// specialized thread-local shadow for return values |
| /// (__msan_retval_tls) and parameters (__msan_param_tls). |
| //===----------------------------------------------------------------------===// |
| |
| #define DEBUG_TYPE "msan" |
| |
| #include "llvm/Transforms/Instrumentation.h" |
| #include "BlackList.h" |
| #include "llvm/ADT/DepthFirstIterator.h" |
| #include "llvm/ADT/SmallString.h" |
| #include "llvm/ADT/SmallVector.h" |
| #include "llvm/ADT/ValueMap.h" |
| #include "llvm/DataLayout.h" |
| #include "llvm/Function.h" |
| #include "llvm/IRBuilder.h" |
| #include "llvm/InlineAsm.h" |
| #include "llvm/InstVisitor.h" |
| #include "llvm/IntrinsicInst.h" |
| #include "llvm/LLVMContext.h" |
| #include "llvm/MDBuilder.h" |
| #include "llvm/Module.h" |
| #include "llvm/Support/CommandLine.h" |
| #include "llvm/Support/Compiler.h" |
| #include "llvm/Support/Debug.h" |
| #include "llvm/Support/raw_ostream.h" |
| #include "llvm/Transforms/Utils/BasicBlockUtils.h" |
| #include "llvm/Transforms/Utils/ModuleUtils.h" |
| #include "llvm/Type.h" |
| |
| using namespace llvm; |
| |
| 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 |
| // yet. |
| // FIXME: this should be a top-level clang flag, e.g. |
| // -fmemory-sanitizer-full. |
| static cl::opt<bool> ClTrackOrigins("msan-track-origins", |
| cl::desc("Track origins (allocation sites) of poisoned memory"), |
| cl::Hidden, cl::init(false)); |
| static cl::opt<bool> ClKeepGoing("msan-keep-going", |
| cl::desc("keep going after reporting a UMR"), |
| cl::Hidden, cl::init(false)); |
| static cl::opt<bool> ClPoisonStack("msan-poison-stack", |
| cl::desc("poison uninitialized stack variables"), |
| cl::Hidden, cl::init(true)); |
| static cl::opt<bool> ClPoisonStackWithCall("msan-poison-stack-with-call", |
| cl::desc("poison uninitialized stack variables with a call"), |
| cl::Hidden, cl::init(false)); |
| static cl::opt<int> ClPoisonStackPattern("msan-poison-stack-pattern", |
| cl::desc("poison uninitialized stack variables with the given patter"), |
| cl::Hidden, cl::init(0xff)); |
| |
| static cl::opt<bool> ClHandleICmp("msan-handle-icmp", |
| cl::desc("propagate shadow through ICmpEQ and ICmpNE"), |
| cl::Hidden, cl::init(true)); |
| |
| static cl::opt<bool> ClStoreCleanOrigin("msan-store-clean-origin", |
| cl::desc("store origin for clean (fully initialized) values"), |
| cl::Hidden, cl::init(false)); |
| |
| // This flag controls whether we check the shadow of the address |
| // operand of load or store. Such bugs are very rare, since load from |
| // a garbage address typically results in SEGV, but still happen |
| // (e.g. only lower bits of address are garbage, or the access happens |
| // early at program startup where malloc-ed memory is more likely to |
| // be zeroed. As of 2012-08-28 this flag adds 20% slowdown. |
| static cl::opt<bool> ClCheckAccessAddress("msan-check-access-address", |
| cl::desc("report accesses through a pointer which has poisoned shadow"), |
| cl::Hidden, cl::init(true)); |
| |
| static cl::opt<bool> ClDumpStrictInstructions("msan-dump-strict-instructions", |
| 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); |
| |
| namespace { |
| |
| /// \brief An instrumentation pass implementing detection of uninitialized |
| /// reads. |
| /// |
| /// MemorySanitizer: instrument the code in module to find |
| /// uninitialized reads. |
| class MemorySanitizer : public FunctionPass { |
| public: |
| MemorySanitizer() : FunctionPass(ID), TD(0), WarningFn(0) { } |
| const char *getPassName() const { return "MemorySanitizer"; } |
| bool runOnFunction(Function &F); |
| bool doInitialization(Module &M); |
| static char ID; // Pass identification, replacement for typeid. |
| |
| private: |
| void initializeCallbacks(Module &M); |
| |
| DataLayout *TD; |
| LLVMContext *C; |
| Type *IntptrTy; |
| Type *OriginTy; |
| /// \brief Thread-local shadow storage for function parameters. |
| GlobalVariable *ParamTLS; |
| /// \brief Thread-local origin storage for function parameters. |
| GlobalVariable *ParamOriginTLS; |
| /// \brief Thread-local shadow storage for function return value. |
| GlobalVariable *RetvalTLS; |
| /// \brief Thread-local origin storage for function return value. |
| GlobalVariable *RetvalOriginTLS; |
| /// \brief Thread-local shadow storage for in-register va_arg function |
| /// parameters (x86_64-specific). |
| GlobalVariable *VAArgTLS; |
| /// \brief Thread-local shadow storage for va_arg overflow area |
| /// (x86_64-specific). |
| GlobalVariable *VAArgOverflowSizeTLS; |
| /// \brief Thread-local space used to pass origin value to the UMR reporting |
| /// function. |
| GlobalVariable *OriginTLS; |
| |
| /// \brief The run-time callback to print a warning. |
| Value *WarningFn; |
| /// \brief Run-time helper that copies origin info for a memory range. |
| Value *MsanCopyOriginFn; |
| /// \brief Run-time helper that generates a new origin value for a stack |
| /// allocation. |
| Value *MsanSetAllocaOriginFn; |
| /// \brief Run-time helper that poisons stack on function entry. |
| Value *MsanPoisonStackFn; |
| /// \brief MSan runtime replacements for memmove, memcpy and memset. |
| Value *MemmoveFn, *MemcpyFn, *MemsetFn; |
| |
| /// \brief Address mask used in application-to-shadow address calculation. |
| /// ShadowAddr is computed as ApplicationAddr & ~ShadowMask. |
| uint64_t ShadowMask; |
| /// \brief Offset of the origin shadow from the "normal" shadow. |
| /// OriginAddr is computed as (ShadowAddr + OriginOffset) & ~3ULL |
| uint64_t OriginOffset; |
| /// \brief Branch weights for error reporting. |
| MDNode *ColdCallWeights; |
| /// \brief Branch weights for origin store. |
| MDNode *OriginStoreWeights; |
| /// \brief The blacklist. |
| OwningPtr<BlackList> BL; |
| /// \brief An empty volatile inline asm that prevents callback merge. |
| InlineAsm *EmptyAsm; |
| |
| friend struct MemorySanitizerVisitor; |
| friend struct VarArgAMD64Helper; |
| }; |
| } // namespace |
| |
| char MemorySanitizer::ID = 0; |
| INITIALIZE_PASS(MemorySanitizer, "msan", |
| "MemorySanitizer: detects uninitialized reads.", |
| false, false) |
| |
| FunctionPass *llvm::createMemorySanitizerPass() { |
| return new MemorySanitizer(); |
| } |
| |
| /// \brief Create a non-const global initialized with the given string. |
| /// |
| /// Creates a writable global for Str so that we can pass it to the |
| /// run-time lib. Runtime uses first 4 bytes of the string to store the |
| /// frame ID, so the string needs to be mutable. |
| static GlobalVariable *createPrivateNonConstGlobalForString(Module &M, |
| StringRef Str) { |
| Constant *StrConst = ConstantDataArray::getString(M.getContext(), Str); |
| return new GlobalVariable(M, StrConst->getType(), /*isConstant=*/false, |
| GlobalValue::PrivateLinkage, StrConst, ""); |
| } |
| |
| |
| /// \brief Insert extern declaration of runtime-provided functions and globals. |
| void MemorySanitizer::initializeCallbacks(Module &M) { |
| // Only do this once. |
| if (WarningFn) |
| return; |
| |
| IRBuilder<> IRB(*C); |
| // Create the callback. |
| // FIXME: this function should have "Cold" calling conv, |
| // which is not yet implemented. |
| StringRef WarningFnName = ClKeepGoing ? "__msan_warning" |
| : "__msan_warning_noreturn"; |
| WarningFn = M.getOrInsertFunction(WarningFnName, IRB.getVoidTy(), NULL); |
| |
| MsanCopyOriginFn = M.getOrInsertFunction( |
| "__msan_copy_origin", IRB.getVoidTy(), IRB.getInt8PtrTy(), |
| IRB.getInt8PtrTy(), IntptrTy, NULL); |
| MsanSetAllocaOriginFn = M.getOrInsertFunction( |
| "__msan_set_alloca_origin", IRB.getVoidTy(), IRB.getInt8PtrTy(), IntptrTy, |
| IRB.getInt8PtrTy(), NULL); |
| MsanPoisonStackFn = M.getOrInsertFunction( |
| "__msan_poison_stack", IRB.getVoidTy(), IRB.getInt8PtrTy(), IntptrTy, NULL); |
| MemmoveFn = M.getOrInsertFunction( |
| "__msan_memmove", IRB.getInt8PtrTy(), IRB.getInt8PtrTy(), |
| IRB.getInt8PtrTy(), IntptrTy, NULL); |
| MemcpyFn = M.getOrInsertFunction( |
| "__msan_memcpy", IRB.getInt8PtrTy(), IRB.getInt8PtrTy(), IRB.getInt8PtrTy(), |
| IntptrTy, NULL); |
| MemsetFn = M.getOrInsertFunction( |
| "__msan_memset", IRB.getInt8PtrTy(), IRB.getInt8PtrTy(), IRB.getInt32Ty(), |
| IntptrTy, NULL); |
| |
| // Create globals. |
| RetvalTLS = new GlobalVariable( |
| M, ArrayType::get(IRB.getInt64Ty(), 8), false, |
| GlobalVariable::ExternalLinkage, 0, "__msan_retval_tls", 0, |
| GlobalVariable::GeneralDynamicTLSModel); |
| RetvalOriginTLS = new GlobalVariable( |
| M, OriginTy, false, GlobalVariable::ExternalLinkage, 0, |
| "__msan_retval_origin_tls", 0, GlobalVariable::GeneralDynamicTLSModel); |
| |
| ParamTLS = new GlobalVariable( |
| M, ArrayType::get(IRB.getInt64Ty(), 1000), false, |
| GlobalVariable::ExternalLinkage, 0, "__msan_param_tls", 0, |
| GlobalVariable::GeneralDynamicTLSModel); |
| ParamOriginTLS = new GlobalVariable( |
| M, ArrayType::get(OriginTy, 1000), false, GlobalVariable::ExternalLinkage, |
| 0, "__msan_param_origin_tls", 0, GlobalVariable::GeneralDynamicTLSModel); |
| |
| VAArgTLS = new GlobalVariable( |
| M, ArrayType::get(IRB.getInt64Ty(), 1000), false, |
| GlobalVariable::ExternalLinkage, 0, "__msan_va_arg_tls", 0, |
| GlobalVariable::GeneralDynamicTLSModel); |
| VAArgOverflowSizeTLS = new GlobalVariable( |
| M, IRB.getInt64Ty(), false, GlobalVariable::ExternalLinkage, 0, |
| "__msan_va_arg_overflow_size_tls", 0, |
| GlobalVariable::GeneralDynamicTLSModel); |
| OriginTLS = new GlobalVariable( |
| M, IRB.getInt32Ty(), false, GlobalVariable::ExternalLinkage, 0, |
| "__msan_origin_tls", 0, GlobalVariable::GeneralDynamicTLSModel); |
| |
| // We insert an empty inline asm after __msan_report* to avoid callback merge. |
| EmptyAsm = InlineAsm::get(FunctionType::get(IRB.getVoidTy(), false), |
| StringRef(""), StringRef(""), |
| /*hasSideEffects=*/true); |
| } |
| |
| /// \brief Module-level initialization. |
| /// |
| /// inserts a call to __msan_init to the module's constructor list. |
| bool MemorySanitizer::doInitialization(Module &M) { |
| TD = getAnalysisIfAvailable<DataLayout>(); |
| if (!TD) |
| return false; |
| BL.reset(new BlackList(ClBlackListFile)); |
| C = &(M.getContext()); |
| unsigned PtrSize = TD->getPointerSizeInBits(/* AddressSpace */0); |
| switch (PtrSize) { |
| case 64: |
| ShadowMask = kShadowMask64; |
| OriginOffset = kOriginOffset64; |
| break; |
| case 32: |
| ShadowMask = kShadowMask32; |
| OriginOffset = kOriginOffset32; |
| break; |
| default: |
| report_fatal_error("unsupported pointer size"); |
| break; |
| } |
| |
| IRBuilder<> IRB(*C); |
| IntptrTy = IRB.getIntPtrTy(TD); |
| OriginTy = IRB.getInt32Ty(); |
| |
| ColdCallWeights = MDBuilder(*C).createBranchWeights(1, 1000); |
| OriginStoreWeights = MDBuilder(*C).createBranchWeights(1, 1000); |
| |
| // Insert a call to __msan_init/__msan_track_origins into the module's CTORs. |
| appendToGlobalCtors(M, cast<Function>(M.getOrInsertFunction( |
| "__msan_init", IRB.getVoidTy(), NULL)), 0); |
| |
| new GlobalVariable(M, IRB.getInt32Ty(), true, GlobalValue::WeakODRLinkage, |
| IRB.getInt32(ClTrackOrigins), "__msan_track_origins"); |
| |
| return true; |
| } |
| |
| namespace { |
| |
| /// \brief A helper class that handles instrumentation of VarArg |
| /// functions on a particular platform. |
| /// |
| /// Implementations are expected to insert the instrumentation |
| /// necessary to propagate argument shadow through VarArg function |
| /// calls. Visit* methods are called during an InstVisitor pass over |
| /// the function, and should avoid creating new basic blocks. A new |
| /// instance of this class is created for each instrumented function. |
| struct VarArgHelper { |
| /// \brief Visit a CallSite. |
| virtual void visitCallSite(CallSite &CS, IRBuilder<> &IRB) = 0; |
| |
| /// \brief Visit a va_start call. |
| virtual void visitVAStartInst(VAStartInst &I) = 0; |
| |
| /// \brief Visit a va_copy call. |
| virtual void visitVACopyInst(VACopyInst &I) = 0; |
| |
| /// \brief Finalize function instrumentation. |
| /// |
| /// This method is called after visiting all interesting (see above) |
| /// instructions in a function. |
| virtual void finalizeInstrumentation() = 0; |
| |
| virtual ~VarArgHelper() {} |
| }; |
| |
| struct MemorySanitizerVisitor; |
| |
| VarArgHelper* |
| CreateVarArgHelper(Function &Func, MemorySanitizer &Msan, |
| MemorySanitizerVisitor &Visitor); |
| |
| /// This class does all the work for a given function. Store and Load |
| /// instructions store and load corresponding shadow and origin |
| /// values. Most instructions propagate shadow from arguments to their |
| /// return values. Certain instructions (most importantly, BranchInst) |
| /// test their argument shadow and print reports (with a runtime call) if it's |
| /// non-zero. |
| struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> { |
| Function &F; |
| MemorySanitizer &MS; |
| SmallVector<PHINode *, 16> ShadowPHINodes, OriginPHINodes; |
| ValueMap<Value*, Value*> ShadowMap, OriginMap; |
| bool InsertChecks; |
| OwningPtr<VarArgHelper> VAHelper; |
| |
| // An unfortunate workaround for asymmetric lowering of va_arg stuff. |
| // See a comment in visitCallSite for more details. |
| static const unsigned AMD64GpEndOffset = 48; // AMD64 ABI Draft 0.99.6 p3.5.7 |
| static const unsigned AMD64FpEndOffset = 176; |
| |
| struct ShadowOriginAndInsertPoint { |
| Instruction *Shadow; |
| Instruction *Origin; |
| Instruction *OrigIns; |
| ShadowOriginAndInsertPoint(Instruction *S, Instruction *O, Instruction *I) |
| : Shadow(S), Origin(O), OrigIns(I) { } |
| ShadowOriginAndInsertPoint() : Shadow(0), Origin(0), OrigIns(0) { } |
| }; |
| SmallVector<ShadowOriginAndInsertPoint, 16> InstrumentationList; |
| SmallVector<Instruction*, 16> StoreList; |
| |
| MemorySanitizerVisitor(Function &F, MemorySanitizer &MS) |
| : F(F), MS(MS), VAHelper(CreateVarArgHelper(F, MS, *this)) { |
| InsertChecks = !MS.BL->isIn(F); |
| DEBUG(if (!InsertChecks) |
| dbgs() << "MemorySanitizer is not inserting checks into '" |
| << F.getName() << "'\n"); |
| } |
| |
| void materializeStores() { |
| for (size_t i = 0, n = StoreList.size(); i < n; i++) { |
| StoreInst& I = *dyn_cast<StoreInst>(StoreList[i]); |
| |
| IRBuilder<> IRB(&I); |
| Value *Val = I.getValueOperand(); |
| Value *Addr = I.getPointerOperand(); |
| Value *Shadow = getShadow(Val); |
| Value *ShadowPtr = getShadowPtr(Addr, Shadow->getType(), IRB); |
| |
| StoreInst *NewSI = |
| IRB.CreateAlignedStore(Shadow, ShadowPtr, I.getAlignment()); |
| DEBUG(dbgs() << " STORE: " << *NewSI << "\n"); |
| (void)NewSI; |
| // If the store is volatile, add a check. |
| if (I.isVolatile()) |
| insertCheck(Val, &I); |
| if (ClCheckAccessAddress) |
| insertCheck(Addr, &I); |
| |
| if (ClTrackOrigins) { |
| if (ClStoreCleanOrigin || isa<StructType>(Shadow->getType())) { |
| IRB.CreateStore(getOrigin(Val), getOriginPtr(Addr, IRB)); |
| } else { |
| Value *ConvertedShadow = convertToShadowTyNoVec(Shadow, IRB); |
| |
| Constant *Cst = dyn_cast_or_null<Constant>(ConvertedShadow); |
| // 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 (Cst) |
| continue; |
| |
| Value *Cmp = IRB.CreateICmpNE(ConvertedShadow, |
| getCleanShadow(ConvertedShadow), "_mscmp"); |
| Instruction *CheckTerm = |
| SplitBlockAndInsertIfThen(cast<Instruction>(Cmp), false, |
| MS.OriginStoreWeights); |
| IRBuilder<> IRBNew(CheckTerm); |
| IRBNew.CreateStore(getOrigin(Val), getOriginPtr(Addr, IRBNew)); |
| } |
| } |
| } |
| } |
| |
| void materializeChecks() { |
| for (size_t i = 0, n = InstrumentationList.size(); i < n; i++) { |
| Instruction *Shadow = InstrumentationList[i].Shadow; |
| Instruction *OrigIns = InstrumentationList[i].OrigIns; |
| IRBuilder<> IRB(OrigIns); |
| DEBUG(dbgs() << " SHAD0 : " << *Shadow << "\n"); |
| Value *ConvertedShadow = convertToShadowTyNoVec(Shadow, IRB); |
| DEBUG(dbgs() << " SHAD1 : " << *ConvertedShadow << "\n"); |
| Value *Cmp = IRB.CreateICmpNE(ConvertedShadow, |
| getCleanShadow(ConvertedShadow), "_mscmp"); |
| Instruction *CheckTerm = |
| SplitBlockAndInsertIfThen(cast<Instruction>(Cmp), |
| /* Unreachable */ !ClKeepGoing, |
| MS.ColdCallWeights); |
| |
| IRB.SetInsertPoint(CheckTerm); |
| if (ClTrackOrigins) { |
| Instruction *Origin = InstrumentationList[i].Origin; |
| IRB.CreateStore(Origin ? (Value*)Origin : (Value*)IRB.getInt32(0), |
| MS.OriginTLS); |
| } |
| CallInst *Call = IRB.CreateCall(MS.WarningFn); |
| Call->setDebugLoc(OrigIns->getDebugLoc()); |
| IRB.CreateCall(MS.EmptyAsm); |
| DEBUG(dbgs() << " CHECK: " << *Cmp << "\n"); |
| } |
| DEBUG(dbgs() << "DONE:\n" << F); |
| } |
| |
| /// \brief Add MemorySanitizer instrumentation to a function. |
| bool runOnFunction() { |
| MS.initializeCallbacks(*F.getParent()); |
| if (!MS.TD) return false; |
| // Iterate all BBs in depth-first order and create shadow instructions |
| // for all instructions (where applicable). |
| // For PHI nodes we create dummy shadow PHIs which will be finalized later. |
| for (df_iterator<BasicBlock*> DI = df_begin(&F.getEntryBlock()), |
| DE = df_end(&F.getEntryBlock()); DI != DE; ++DI) { |
| BasicBlock *BB = *DI; |
| visit(*BB); |
| } |
| |
| // Finalize PHI nodes. |
| for (size_t i = 0, n = ShadowPHINodes.size(); i < n; i++) { |
| PHINode *PN = ShadowPHINodes[i]; |
| PHINode *PNS = cast<PHINode>(getShadow(PN)); |
| PHINode *PNO = ClTrackOrigins ? cast<PHINode>(getOrigin(PN)) : 0; |
| 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)); |
| } |
| } |
| |
| VAHelper->finalizeInstrumentation(); |
| |
| // Delayed instrumentation of StoreInst. |
| // This may add new checks to be inserted later. |
| materializeStores(); |
| |
| // Insert shadow value checks. |
| materializeChecks(); |
| |
| return true; |
| } |
| |
| /// \brief Compute the shadow type that corresponds to a given Value. |
| Type *getShadowTy(Value *V) { |
| return getShadowTy(V->getType()); |
| } |
| |
| /// \brief Compute the shadow type that corresponds to a given Type. |
| Type *getShadowTy(Type *OrigTy) { |
| if (!OrigTy->isSized()) { |
| return 0; |
| } |
| // For integer type, shadow is the same as the original type. |
| // This may return weird-sized types like i1. |
| if (IntegerType *IT = dyn_cast<IntegerType>(OrigTy)) |
| return IT; |
| if (VectorType *VT = dyn_cast<VectorType>(OrigTy)) |
| return VectorType::getInteger(VT); |
| if (StructType *ST = dyn_cast<StructType>(OrigTy)) { |
| SmallVector<Type*, 4> Elements; |
| for (unsigned i = 0, n = ST->getNumElements(); i < n; i++) |
| Elements.push_back(getShadowTy(ST->getElementType(i))); |
| StructType *Res = StructType::get(*MS.C, Elements, ST->isPacked()); |
| DEBUG(dbgs() << "getShadowTy: " << *ST << " ===> " << *Res << "\n"); |
| return Res; |
| } |
| uint32_t TypeSize = MS.TD->getTypeStoreSizeInBits(OrigTy); |
| return IntegerType::get(*MS.C, TypeSize); |
| } |
| |
| /// \brief Flatten a vector type. |
| Type *getShadowTyNoVec(Type *ty) { |
| if (VectorType *vt = dyn_cast<VectorType>(ty)) |
| return IntegerType::get(*MS.C, vt->getBitWidth()); |
| return ty; |
| } |
| |
| /// \brief Convert a shadow value to it's flattened variant. |
| Value *convertToShadowTyNoVec(Value *V, IRBuilder<> &IRB) { |
| Type *Ty = V->getType(); |
| Type *NoVecTy = getShadowTyNoVec(Ty); |
| if (Ty == NoVecTy) return V; |
| return IRB.CreateBitCast(V, NoVecTy); |
| } |
| |
| /// \brief Compute the shadow address that corresponds to a given application |
| /// address. |
| /// |
| /// Shadow = Addr & ~ShadowMask. |
| Value *getShadowPtr(Value *Addr, Type *ShadowTy, |
| IRBuilder<> &IRB) { |
| Value *ShadowLong = |
| IRB.CreateAnd(IRB.CreatePointerCast(Addr, MS.IntptrTy), |
| ConstantInt::get(MS.IntptrTy, ~MS.ShadowMask)); |
| return IRB.CreateIntToPtr(ShadowLong, PointerType::get(ShadowTy, 0)); |
| } |
| |
| /// \brief Compute the origin address that corresponds to a given application |
| /// address. |
| /// |
| /// OriginAddr = (ShadowAddr + OriginOffset) & ~3ULL |
| Value *getOriginPtr(Value *Addr, IRBuilder<> &IRB) { |
| Value *ShadowLong = |
| IRB.CreateAnd(IRB.CreatePointerCast(Addr, MS.IntptrTy), |
| ConstantInt::get(MS.IntptrTy, ~MS.ShadowMask)); |
| Value *Add = |
| IRB.CreateAdd(ShadowLong, |
| ConstantInt::get(MS.IntptrTy, MS.OriginOffset)); |
| Value *SecondAnd = |
| IRB.CreateAnd(Add, ConstantInt::get(MS.IntptrTy, ~3ULL)); |
| return IRB.CreateIntToPtr(SecondAnd, PointerType::get(IRB.getInt32Ty(), 0)); |
| } |
| |
| /// \brief Compute the shadow address for a given function argument. |
| /// |
| /// Shadow = ParamTLS+ArgOffset. |
| Value *getShadowPtrForArgument(Value *A, IRBuilder<> &IRB, |
| int ArgOffset) { |
| Value *Base = IRB.CreatePointerCast(MS.ParamTLS, MS.IntptrTy); |
| Base = IRB.CreateAdd(Base, ConstantInt::get(MS.IntptrTy, ArgOffset)); |
| return IRB.CreateIntToPtr(Base, PointerType::get(getShadowTy(A), 0), |
| "_msarg"); |
| } |
| |
| /// \brief Compute the origin address for a given function argument. |
| Value *getOriginPtrForArgument(Value *A, IRBuilder<> &IRB, |
| int ArgOffset) { |
| if (!ClTrackOrigins) return 0; |
| Value *Base = IRB.CreatePointerCast(MS.ParamOriginTLS, MS.IntptrTy); |
| Base = IRB.CreateAdd(Base, ConstantInt::get(MS.IntptrTy, ArgOffset)); |
| return IRB.CreateIntToPtr(Base, PointerType::get(MS.OriginTy, 0), |
| "_msarg_o"); |
| } |
| |
| /// \brief Compute the shadow address for a retval. |
| Value *getShadowPtrForRetval(Value *A, IRBuilder<> &IRB) { |
| Value *Base = IRB.CreatePointerCast(MS.RetvalTLS, MS.IntptrTy); |
| return IRB.CreateIntToPtr(Base, PointerType::get(getShadowTy(A), 0), |
| "_msret"); |
| } |
| |
| /// \brief Compute the origin address for a retval. |
| Value *getOriginPtrForRetval(IRBuilder<> &IRB) { |
| // We keep a single origin for the entire retval. Might be too optimistic. |
| return MS.RetvalOriginTLS; |
| } |
| |
| /// \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; |
| } |
| |
| /// \brief Set Origin to be the origin value for V. |
| void setOrigin(Value *V, Value *Origin) { |
| if (!ClTrackOrigins) return; |
| assert(!OriginMap.count(V) && "Values may only have one origin"); |
| DEBUG(dbgs() << "ORIGIN: " << *V << " ==> " << *Origin << "\n"); |
| OriginMap[V] = Origin; |
| } |
| |
| /// \brief Create a clean shadow value for a given value. |
| /// |
| /// Clean shadow (all zeroes) means all bits of the value are defined |
| /// (initialized). |
| Value *getCleanShadow(Value *V) { |
| Type *ShadowTy = getShadowTy(V); |
| if (!ShadowTy) |
| return 0; |
| return Constant::getNullValue(ShadowTy); |
| } |
| |
| /// \brief Create a dirty shadow of a given shadow type. |
| Constant *getPoisonedShadow(Type *ShadowTy) { |
| 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); |
| } |
| |
| /// \brief Create a clean (zero) origin. |
| Value *getCleanOrigin() { |
| return Constant::getNullValue(MS.OriginTy); |
| } |
| |
| /// \brief Get the shadow value 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 (Instruction *I = dyn_cast<Instruction>(V)) { |
| // For instructions the shadow is already stored in the map. |
| Value *Shadow = ShadowMap[V]; |
| if (!Shadow) { |
| DEBUG(dbgs() << "No shadow: " << *V << "\n" << *(I->getParent())); |
| (void)I; |
| assert(Shadow && "No shadow for a value"); |
| } |
| return Shadow; |
| } |
| if (UndefValue *U = dyn_cast<UndefValue>(V)) { |
| Value *AllOnes = getPoisonedShadow(getShadowTy(V)); |
| DEBUG(dbgs() << "Undef: " << *U << " ==> " << *AllOnes << "\n"); |
| (void)U; |
| return AllOnes; |
| } |
| if (Argument *A = dyn_cast<Argument>(V)) { |
| // For arguments we compute the shadow on demand and store it in the map. |
| Value **ShadowPtr = &ShadowMap[V]; |
| if (*ShadowPtr) |
| return *ShadowPtr; |
| Function *F = A->getParent(); |
| IRBuilder<> EntryIRB(F->getEntryBlock().getFirstNonPHI()); |
| unsigned ArgOffset = 0; |
| for (Function::arg_iterator AI = F->arg_begin(), AE = F->arg_end(); |
| AI != AE; ++AI) { |
| if (!AI->getType()->isSized()) { |
| DEBUG(dbgs() << "Arg is not sized\n"); |
| continue; |
| } |
| unsigned Size = AI->hasByValAttr() |
| ? MS.TD->getTypeAllocSize(AI->getType()->getPointerElementType()) |
| : MS.TD->getTypeAllocSize(AI->getType()); |
| if (A == AI) { |
| Value *Base = getShadowPtrForArgument(AI, EntryIRB, ArgOffset); |
| if (AI->hasByValAttr()) { |
| // ByVal pointer itself has clean shadow. We copy the actual |
| // argument shadow to the underlying memory. |
| Value *Cpy = EntryIRB.CreateMemCpy( |
| getShadowPtr(V, EntryIRB.getInt8Ty(), EntryIRB), |
| Base, Size, AI->getParamAlignment()); |
| DEBUG(dbgs() << " ByValCpy: " << *Cpy << "\n"); |
| (void)Cpy; |
| *ShadowPtr = getCleanShadow(V); |
| } else { |
| *ShadowPtr = EntryIRB.CreateLoad(Base); |
| } |
| DEBUG(dbgs() << " ARG: " << *AI << " ==> " << |
| **ShadowPtr << "\n"); |
| if (ClTrackOrigins) { |
| Value* OriginPtr = getOriginPtrForArgument(AI, EntryIRB, ArgOffset); |
| setOrigin(A, EntryIRB.CreateLoad(OriginPtr)); |
| } |
| } |
| ArgOffset += DataLayout::RoundUpAlignment(Size, 8); |
| } |
| assert(*ShadowPtr && "Could not find shadow for an argument"); |
| return *ShadowPtr; |
| } |
| // For everything else the shadow is zero. |
| return getCleanShadow(V); |
| } |
| |
| /// \brief Get the shadow for i-th argument of the instruction I. |
| Value *getShadow(Instruction *I, int i) { |
| return getShadow(I->getOperand(i)); |
| } |
| |
| /// \brief Get the origin for a value. |
| Value *getOrigin(Value *V) { |
| if (!ClTrackOrigins) return 0; |
| if (isa<Instruction>(V) || isa<Argument>(V)) { |
| Value *Origin = OriginMap[V]; |
| if (!Origin) { |
| DEBUG(dbgs() << "NO ORIGIN: " << *V << "\n"); |
| Origin = getCleanOrigin(); |
| } |
| return Origin; |
| } |
| return getCleanOrigin(); |
| } |
| |
| /// \brief Get the origin for i-th argument of the instruction I. |
| Value *getOrigin(Instruction *I, int i) { |
| return getOrigin(I->getOperand(i)); |
| } |
| |
| /// \brief Remember the place where a shadow check should be inserted. |
| /// |
| /// This location will be later instrumented with a check that will print a |
| /// UMR warning in runtime if the value is not fully defined. |
| void insertCheck(Value *Val, Instruction *OrigIns) { |
| assert(Val); |
| if (!InsertChecks) return; |
| Instruction *Shadow = dyn_cast_or_null<Instruction>(getShadow(Val)); |
| if (!Shadow) return; |
| #ifndef NDEBUG |
| Type *ShadowTy = Shadow->getType(); |
| assert((isa<IntegerType>(ShadowTy) || isa<VectorType>(ShadowTy)) && |
| "Can only insert checks for integer and vector shadow types"); |
| #endif |
| Instruction *Origin = dyn_cast_or_null<Instruction>(getOrigin(Val)); |
| InstrumentationList.push_back( |
| ShadowOriginAndInsertPoint(Shadow, Origin, OrigIns)); |
| } |
| |
| // ------------------- Visitors. |
| |
| /// \brief Instrument LoadInst |
| /// |
| /// Loads the corresponding shadow and (optionally) origin. |
| /// Optionally, checks that the load address is fully defined. |
| void visitLoadInst(LoadInst &I) { |
| assert(I.getType()->isSized() && "Load type must have size"); |
| IRBuilder<> IRB(&I); |
| Type *ShadowTy = getShadowTy(&I); |
| Value *Addr = I.getPointerOperand(); |
| Value *ShadowPtr = getShadowPtr(Addr, ShadowTy, IRB); |
| setShadow(&I, IRB.CreateAlignedLoad(ShadowPtr, I.getAlignment(), "_msld")); |
| |
| if (ClCheckAccessAddress) |
| insertCheck(I.getPointerOperand(), &I); |
| |
| if (ClTrackOrigins) |
| setOrigin(&I, IRB.CreateLoad(getOriginPtr(Addr, IRB))); |
| } |
| |
| /// \brief Instrument StoreInst |
| /// |
| /// Stores the corresponding shadow and (optionally) origin. |
| /// Optionally, checks that the store address is fully defined. |
| /// Volatile stores check that the value being stored is fully defined. |
| void visitStoreInst(StoreInst &I) { |
| StoreList.push_back(&I); |
| } |
| |
| // Vector manipulation. |
| void visitExtractElementInst(ExtractElementInst &I) { |
| insertCheck(I.getOperand(1), &I); |
| IRBuilder<> IRB(&I); |
| setShadow(&I, IRB.CreateExtractElement(getShadow(&I, 0), I.getOperand(1), |
| "_msprop")); |
| setOrigin(&I, getOrigin(&I, 0)); |
| } |
| |
| void visitInsertElementInst(InsertElementInst &I) { |
| insertCheck(I.getOperand(2), &I); |
| IRBuilder<> IRB(&I); |
| setShadow(&I, IRB.CreateInsertElement(getShadow(&I, 0), getShadow(&I, 1), |
| I.getOperand(2), "_msprop")); |
| setOriginForNaryOp(I); |
| } |
| |
| void visitShuffleVectorInst(ShuffleVectorInst &I) { |
| insertCheck(I.getOperand(2), &I); |
| IRBuilder<> IRB(&I); |
| setShadow(&I, IRB.CreateShuffleVector(getShadow(&I, 0), getShadow(&I, 1), |
| I.getOperand(2), "_msprop")); |
| setOriginForNaryOp(I); |
| } |
| |
| // Casts. |
| void visitSExtInst(SExtInst &I) { |
| IRBuilder<> IRB(&I); |
| setShadow(&I, IRB.CreateSExt(getShadow(&I, 0), I.getType(), "_msprop")); |
| setOrigin(&I, getOrigin(&I, 0)); |
| } |
| |
| void visitZExtInst(ZExtInst &I) { |
| IRBuilder<> IRB(&I); |
| setShadow(&I, IRB.CreateZExt(getShadow(&I, 0), I.getType(), "_msprop")); |
| setOrigin(&I, getOrigin(&I, 0)); |
| } |
| |
| void visitTruncInst(TruncInst &I) { |
| IRBuilder<> IRB(&I); |
| setShadow(&I, IRB.CreateTrunc(getShadow(&I, 0), I.getType(), "_msprop")); |
| setOrigin(&I, getOrigin(&I, 0)); |
| } |
| |
| void visitBitCastInst(BitCastInst &I) { |
| IRBuilder<> IRB(&I); |
| setShadow(&I, IRB.CreateBitCast(getShadow(&I, 0), getShadowTy(&I))); |
| setOrigin(&I, getOrigin(&I, 0)); |
| } |
| |
| void visitPtrToIntInst(PtrToIntInst &I) { |
| IRBuilder<> IRB(&I); |
| setShadow(&I, IRB.CreateIntCast(getShadow(&I, 0), getShadowTy(&I), false, |
| "_msprop_ptrtoint")); |
| setOrigin(&I, getOrigin(&I, 0)); |
| } |
| |
| void visitIntToPtrInst(IntToPtrInst &I) { |
| IRBuilder<> IRB(&I); |
| setShadow(&I, IRB.CreateIntCast(getShadow(&I, 0), getShadowTy(&I), false, |
| "_msprop_inttoptr")); |
| setOrigin(&I, getOrigin(&I, 0)); |
| } |
| |
| void visitFPToSIInst(CastInst& I) { handleShadowOr(I); } |
| void visitFPToUIInst(CastInst& I) { handleShadowOr(I); } |
| void visitSIToFPInst(CastInst& I) { handleShadowOr(I); } |
| void visitUIToFPInst(CastInst& I) { handleShadowOr(I); } |
| void visitFPExtInst(CastInst& I) { handleShadowOr(I); } |
| void visitFPTruncInst(CastInst& I) { handleShadowOr(I); } |
| |
| /// \brief Propagate shadow for bitwise AND. |
| /// |
| /// This code is exact, i.e. if, for example, a bit in the left argument |
| /// is defined and 0, then neither the value not definedness of the |
| /// corresponding bit in B don't affect the resulting shadow. |
| void visitAnd(BinaryOperator &I) { |
| IRBuilder<> IRB(&I); |
| // "And" of 0 and a poisoned value results in unpoisoned value. |
| // 1&1 => 1; 0&1 => 0; p&1 => p; |
| // 1&0 => 0; 0&0 => 0; p&0 => 0; |
| // 1&p => p; 0&p => 0; p&p => p; |
| // S = (S1 & S2) | (V1 & S2) | (S1 & V2) |
| Value *S1 = getShadow(&I, 0); |
| Value *S2 = getShadow(&I, 1); |
| Value *V1 = I.getOperand(0); |
| Value *V2 = I.getOperand(1); |
| if (V1->getType() != S1->getType()) { |
| V1 = IRB.CreateIntCast(V1, S1->getType(), false); |
| V2 = IRB.CreateIntCast(V2, S2->getType(), false); |
| } |
| Value *S1S2 = IRB.CreateAnd(S1, S2); |
| Value *V1S2 = IRB.CreateAnd(V1, S2); |
| Value *S1V2 = IRB.CreateAnd(S1, V2); |
| setShadow(&I, IRB.CreateOr(S1S2, IRB.CreateOr(V1S2, S1V2))); |
| setOriginForNaryOp(I); |
| } |
| |
| void visitOr(BinaryOperator &I) { |
| IRBuilder<> IRB(&I); |
| // "Or" of 1 and a poisoned value results in unpoisoned value. |
| // 1|1 => 1; 0|1 => 1; p|1 => 1; |
| // 1|0 => 1; 0|0 => 0; p|0 => p; |
| // 1|p => 1; 0|p => p; p|p => p; |
| // S = (S1 & S2) | (~V1 & S2) | (S1 & ~V2) |
| Value *S1 = getShadow(&I, 0); |
| Value *S2 = getShadow(&I, 1); |
| Value *V1 = IRB.CreateNot(I.getOperand(0)); |
| Value *V2 = IRB.CreateNot(I.getOperand(1)); |
| if (V1->getType() != S1->getType()) { |
| V1 = IRB.CreateIntCast(V1, S1->getType(), false); |
| V2 = IRB.CreateIntCast(V2, S2->getType(), false); |
| } |
| Value *S1S2 = IRB.CreateAnd(S1, S2); |
| Value *V1S2 = IRB.CreateAnd(V1, S2); |
| Value *S1V2 = IRB.CreateAnd(S1, V2); |
| setShadow(&I, IRB.CreateOr(S1S2, IRB.CreateOr(V1S2, S1V2))); |
| setOriginForNaryOp(I); |
| } |
| |
| /// \brief Default propagation of shadow and/or origin. |
| /// |
| /// This class implements the general case of shadow propagation, used in all |
| /// cases where we don't know and/or don't care about what the operation |
| /// actually does. It converts all input shadow values to a common type |
| /// (extending or truncating as necessary), and bitwise OR's them. |
| /// |
| /// This is much cheaper than inserting checks (i.e. requiring inputs to be |
| /// fully initialized), and less prone to false positives. |
| /// |
| /// This class also implements the general case of origin propagation. For a |
| /// Nary operation, result origin is set to the origin of an argument that is |
| /// not entirely initialized. If there is more than one such arguments, the |
| /// rightmost of them is picked. It does not matter which one is picked if all |
| /// arguments are initialized. |
| template <bool CombineShadow> |
| class Combiner { |
| Value *Shadow; |
| Value *Origin; |
| IRBuilder<> &IRB; |
| MemorySanitizerVisitor *MSV; |
| |
| public: |
| Combiner(MemorySanitizerVisitor *MSV, IRBuilder<> &IRB) : |
| Shadow(0), Origin(0), IRB(IRB), MSV(MSV) {} |
| |
| /// \brief Add a pair of shadow and origin values to the mix. |
| Combiner &Add(Value *OpShadow, Value *OpOrigin) { |
| if (CombineShadow) { |
| assert(OpShadow); |
| if (!Shadow) |
| Shadow = OpShadow; |
| else { |
| OpShadow = MSV->CreateShadowCast(IRB, OpShadow, Shadow->getType()); |
| Shadow = IRB.CreateOr(Shadow, OpShadow, "_msprop"); |
| } |
| } |
| |
| if (ClTrackOrigins) { |
| assert(OpOrigin); |
| 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); |
| } |
| } |
| return *this; |
| } |
| |
| /// \brief Add an application value to the mix. |
| Combiner &Add(Value *V) { |
| Value *OpShadow = MSV->getShadow(V); |
| Value *OpOrigin = ClTrackOrigins ? MSV->getOrigin(V) : 0; |
| return Add(OpShadow, OpOrigin); |
| } |
| |
| /// \brief Set the current combined values as the given instruction's shadow |
| /// and origin. |
| void Done(Instruction *I) { |
| if (CombineShadow) { |
| assert(Shadow); |
| Shadow = MSV->CreateShadowCast(IRB, Shadow, MSV->getShadowTy(I)); |
| MSV->setShadow(I, Shadow); |
| } |
| if (ClTrackOrigins) { |
| assert(Origin); |
| MSV->setOrigin(I, Origin); |
| } |
| } |
| }; |
| |
| typedef Combiner<true> ShadowAndOriginCombiner; |
| typedef Combiner<false> OriginCombiner; |
| |
| /// \brief Propagate origin for arbitrary operation. |
| void setOriginForNaryOp(Instruction &I) { |
| if (!ClTrackOrigins) return; |
| IRBuilder<> IRB(&I); |
| OriginCombiner OC(this, IRB); |
| for (Instruction::op_iterator OI = I.op_begin(); OI != I.op_end(); ++OI) |
| OC.Add(OI->get()); |
| OC.Done(&I); |
| } |
| |
| size_t VectorOrPrimitiveTypeSizeInBits(Type *Ty) { |
| return Ty->isVectorTy() ? |
| Ty->getVectorNumElements() * Ty->getScalarSizeInBits() : |
| Ty->getPrimitiveSizeInBits(); |
| } |
| |
| /// \brief Cast between two shadow types, extending or truncating as |
| /// necessary. |
| Value *CreateShadowCast(IRBuilder<> &IRB, Value *V, Type *dstTy) { |
| Type *srcTy = V->getType(); |
| if (dstTy->isIntegerTy() && srcTy->isIntegerTy()) |
| return IRB.CreateIntCast(V, dstTy, false); |
| if (dstTy->isVectorTy() && srcTy->isVectorTy() && |
| dstTy->getVectorNumElements() == srcTy->getVectorNumElements()) |
| return IRB.CreateIntCast(V, dstTy, false); |
| size_t srcSizeInBits = VectorOrPrimitiveTypeSizeInBits(srcTy); |
| size_t dstSizeInBits = VectorOrPrimitiveTypeSizeInBits(dstTy); |
| Value *V1 = IRB.CreateBitCast(V, Type::getIntNTy(*MS.C, srcSizeInBits)); |
| Value *V2 = |
| IRB.CreateIntCast(V1, Type::getIntNTy(*MS.C, dstSizeInBits), false); |
| return IRB.CreateBitCast(V2, dstTy); |
| // TODO: handle struct types. |
| } |
| |
| /// \brief Propagate shadow for arbitrary operation. |
| void handleShadowOr(Instruction &I) { |
| IRBuilder<> IRB(&I); |
| ShadowAndOriginCombiner SC(this, IRB); |
| for (Instruction::op_iterator OI = I.op_begin(); OI != I.op_end(); ++OI) |
| SC.Add(OI->get()); |
| SC.Done(&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); |
| // Strict on the second argument. |
| insertCheck(I.getOperand(1), &I); |
| setShadow(&I, getShadow(&I, 0)); |
| setOrigin(&I, getOrigin(&I, 0)); |
| } |
| |
| void visitUDiv(BinaryOperator &I) { handleDiv(I); } |
| void visitSDiv(BinaryOperator &I) { handleDiv(I); } |
| void visitFDiv(BinaryOperator &I) { handleDiv(I); } |
| void visitURem(BinaryOperator &I) { handleDiv(I); } |
| void visitSRem(BinaryOperator &I) { handleDiv(I); } |
| void visitFRem(BinaryOperator &I) { handleDiv(I); } |
| |
| /// \brief Instrument == and != comparisons. |
| /// |
| /// Sometimes the comparison result is known even if some of the bits of the |
| /// arguments are not. |
| void handleEqualityComparison(ICmpInst &I) { |
| IRBuilder<> IRB(&I); |
| Value *A = I.getOperand(0); |
| Value *B = I.getOperand(1); |
| Value *Sa = getShadow(A); |
| Value *Sb = getShadow(B); |
| if (A->getType()->isPointerTy()) |
| A = IRB.CreatePointerCast(A, MS.IntptrTy); |
| if (B->getType()->isPointerTy()) |
| B = IRB.CreatePointerCast(B, MS.IntptrTy); |
| // A == B <==> (C = A^B) == 0 |
| // A != B <==> (C = A^B) != 0 |
| // Sc = Sa | Sb |
| Value *C = IRB.CreateXor(A, B); |
| Value *Sc = IRB.CreateOr(Sa, Sb); |
| // Now dealing with i = (C == 0) comparison (or C != 0, does not matter now) |
| // Result is defined if one of the following is true |
| // * there is a defined 1 bit in C |
| // * C is fully defined |
| // Si = !(C & ~Sc) && Sc |
| Value *Zero = Constant::getNullValue(Sc->getType()); |
| Value *MinusOne = Constant::getAllOnesValue(Sc->getType()); |
| Value *Si = |
| IRB.CreateAnd(IRB.CreateICmpNE(Sc, Zero), |
| IRB.CreateICmpEQ( |
| IRB.CreateAnd(IRB.CreateXor(Sc, MinusOne), C), Zero)); |
| Si->setName("_msprop_icmp"); |
| setShadow(&I, Si); |
| setOriginForNaryOp(I); |
| } |
| |
| /// \brief Instrument signed relational comparisons. |
| /// |
| /// Handle (x<0) and (x>=0) comparisons (essentially, sign bit tests) by |
| /// propagating the highest bit of the shadow. Everything else is delegated |
| /// to handleShadowOr(). |
| void handleSignedRelationalComparison(ICmpInst &I) { |
| Constant *constOp0 = dyn_cast<Constant>(I.getOperand(0)); |
| Constant *constOp1 = dyn_cast<Constant>(I.getOperand(1)); |
| Value* op = NULL; |
| CmpInst::Predicate pre = I.getPredicate(); |
| if (constOp0 && constOp0->isNullValue() && |
| (pre == CmpInst::ICMP_SGT || pre == CmpInst::ICMP_SLE)) { |
| op = I.getOperand(1); |
| } else if (constOp1 && constOp1->isNullValue() && |
| (pre == CmpInst::ICMP_SLT || pre == CmpInst::ICMP_SGE)) { |
| op = I.getOperand(0); |
| } |
| if (op) { |
| IRBuilder<> IRB(&I); |
| Value* Shadow = |
| IRB.CreateICmpSLT(getShadow(op), getCleanShadow(op), "_msprop_icmpslt"); |
| setShadow(&I, Shadow); |
| setOrigin(&I, getOrigin(op)); |
| } else { |
| handleShadowOr(I); |
| } |
| } |
| |
| void visitICmpInst(ICmpInst &I) { |
| if (ClHandleICmp && I.isEquality()) |
| handleEqualityComparison(I); |
| else if (ClHandleICmp && I.isSigned() && I.isRelational()) |
| handleSignedRelationalComparison(I); |
| else |
| handleShadowOr(I); |
| } |
| |
| void visitFCmpInst(FCmpInst &I) { |
| handleShadowOr(I); |
| } |
| |
| void handleShift(BinaryOperator &I) { |
| IRBuilder<> IRB(&I); |
| // If any of the S2 bits are poisoned, the whole thing is poisoned. |
| // Otherwise perform the same shift on S1. |
| Value *S1 = getShadow(&I, 0); |
| Value *S2 = getShadow(&I, 1); |
| Value *S2Conv = IRB.CreateSExt(IRB.CreateICmpNE(S2, getCleanShadow(S2)), |
| S2->getType()); |
| Value *V2 = I.getOperand(1); |
| Value *Shift = IRB.CreateBinOp(I.getOpcode(), S1, V2); |
| setShadow(&I, IRB.CreateOr(Shift, S2Conv)); |
| setOriginForNaryOp(I); |
| } |
| |
| void visitShl(BinaryOperator &I) { handleShift(I); } |
| void visitAShr(BinaryOperator &I) { handleShift(I); } |
| void visitLShr(BinaryOperator &I) { handleShift(I); } |
| |
| /// \brief Instrument llvm.memmove |
| /// |
| /// At this point we don't know if llvm.memmove will be inlined or not. |
| /// If we don't instrument it and it gets inlined, |
| /// our interceptor will not kick in and we will lose the memmove. |
| /// If we instrument the call here, but it does not get inlined, |
| /// we will memove the shadow twice: which is bad in case |
| /// of overlapping regions. So, we simply lower the intrinsic to a call. |
| /// |
| /// Similar situation exists for memcpy and memset. |
| void visitMemMoveInst(MemMoveInst &I) { |
| IRBuilder<> IRB(&I); |
| IRB.CreateCall3( |
| MS.MemmoveFn, |
| IRB.CreatePointerCast(I.getArgOperand(0), IRB.getInt8PtrTy()), |
| IRB.CreatePointerCast(I.getArgOperand(1), IRB.getInt8PtrTy()), |
| IRB.CreateIntCast(I.getArgOperand(2), MS.IntptrTy, false)); |
| I.eraseFromParent(); |
| } |
| |
| // Similar to memmove: avoid copying shadow twice. |
| // This is somewhat unfortunate as it may slowdown small constant memcpys. |
| // FIXME: consider doing manual inline for small constant sizes and proper |
| // alignment. |
| void visitMemCpyInst(MemCpyInst &I) { |
| IRBuilder<> IRB(&I); |
| IRB.CreateCall3( |
| MS.MemcpyFn, |
| IRB.CreatePointerCast(I.getArgOperand(0), IRB.getInt8PtrTy()), |
| IRB.CreatePointerCast(I.getArgOperand(1), IRB.getInt8PtrTy()), |
| IRB.CreateIntCast(I.getArgOperand(2), MS.IntptrTy, false)); |
| I.eraseFromParent(); |
| } |
| |
| // Same as memcpy. |
| void visitMemSetInst(MemSetInst &I) { |
| IRBuilder<> IRB(&I); |
| IRB.CreateCall3( |
| MS.MemsetFn, |
| IRB.CreatePointerCast(I.getArgOperand(0), IRB.getInt8PtrTy()), |
| IRB.CreateIntCast(I.getArgOperand(1), IRB.getInt32Ty(), false), |
| IRB.CreateIntCast(I.getArgOperand(2), MS.IntptrTy, false)); |
| I.eraseFromParent(); |
| } |
| |
| void visitVAStartInst(VAStartInst &I) { |
| VAHelper->visitVAStartInst(I); |
| } |
| |
| void visitVACopyInst(VACopyInst &I) { |
| VAHelper->visitVACopyInst(I); |
| } |
| |
| void handleBswap(IntrinsicInst &I) { |
| IRBuilder<> IRB(&I); |
| Value *Op = I.getArgOperand(0); |
| Type *OpType = Op->getType(); |
| Function *BswapFunc = Intrinsic::getDeclaration( |
| F.getParent(), Intrinsic::bswap, ArrayRef<Type*>(&OpType, 1)); |
| setShadow(&I, IRB.CreateCall(BswapFunc, getShadow(Op))); |
| setOrigin(&I, getOrigin(Op)); |
| } |
| |
| void visitIntrinsicInst(IntrinsicInst &I) { |
| switch (I.getIntrinsicID()) { |
| case llvm::Intrinsic::bswap: |
| handleBswap(I); |
| break; |
| default: |
| visitInstruction(I); |
| break; |
| } |
| } |
| |
| void visitCallSite(CallSite CS) { |
| Instruction &I = *CS.getInstruction(); |
| assert((CS.isCall() || CS.isInvoke()) && "Unknown type of CallSite"); |
| if (CS.isCall()) { |
| CallInst *Call = cast<CallInst>(&I); |
| |
| // For inline asm, do the usual thing: check argument shadow and mark all |
| // outputs as clean. Note that any side effects of the inline asm that are |
| // not immediately visible in its constraints are not handled. |
| if (Call->isInlineAsm()) { |
| 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 |
| // will become a non-readonly function after it is instrumented by us. To |
| // prevent this code from being optimized out, mark that function |
| // non-readonly in advance. |
| if (Function *Func = Call->getCalledFunction()) { |
| // Clear out readonly/readnone attributes. |
| AttrBuilder B; |
| B.addAttribute(Attribute::ReadOnly) |
| .addAttribute(Attribute::ReadNone); |
| Func->removeAttribute(AttributeSet::FunctionIndex, |
| Attribute::get(Func->getContext(), B)); |
| } |
| } |
| IRBuilder<> IRB(&I); |
| unsigned ArgOffset = 0; |
| DEBUG(dbgs() << " CallSite: " << I << "\n"); |
| for (CallSite::arg_iterator ArgIt = CS.arg_begin(), End = CS.arg_end(); |
| ArgIt != End; ++ArgIt) { |
| Value *A = *ArgIt; |
| unsigned i = ArgIt - CS.arg_begin(); |
| if (!A->getType()->isSized()) { |
| DEBUG(dbgs() << "Arg " << i << " is not sized: " << I << "\n"); |
| continue; |
| } |
| unsigned Size = 0; |
| Value *Store = 0; |
| // Compute the Shadow for arg even if it is ByVal, because |
| // in that case getShadow() will copy the actual arg shadow to |
| // __msan_param_tls. |
| Value *ArgShadow = getShadow(A); |
| Value *ArgShadowBase = getShadowPtrForArgument(A, IRB, ArgOffset); |
| DEBUG(dbgs() << " Arg#" << i << ": " << *A << |
| " Shadow: " << *ArgShadow << "\n"); |
| if (CS.paramHasAttr(i + 1, Attribute::ByVal)) { |
| assert(A->getType()->isPointerTy() && |
| "ByVal argument is not a pointer!"); |
| Size = MS.TD->getTypeAllocSize(A->getType()->getPointerElementType()); |
| unsigned Alignment = CS.getParamAlignment(i + 1); |
| Store = IRB.CreateMemCpy(ArgShadowBase, |
| getShadowPtr(A, Type::getInt8Ty(*MS.C), IRB), |
| Size, Alignment); |
| } else { |
| Size = MS.TD->getTypeAllocSize(A->getType()); |
| Store = IRB.CreateAlignedStore(ArgShadow, ArgShadowBase, |
| kShadowTLSAlignment); |
| } |
| if (ClTrackOrigins) |
| IRB.CreateStore(getOrigin(A), |
| getOriginPtrForArgument(A, IRB, ArgOffset)); |
| assert(Size != 0 && Store != 0); |
| DEBUG(dbgs() << " Param:" << *Store << "\n"); |
| ArgOffset += DataLayout::RoundUpAlignment(Size, 8); |
| } |
| DEBUG(dbgs() << " done with call args\n"); |
| |
| FunctionType *FT = |
| cast<FunctionType>(CS.getCalledValue()->getType()-> getContainedType(0)); |
| if (FT->isVarArg()) { |
| VAHelper->visitCallSite(CS, IRB); |
| } |
| |
| // Now, get the shadow for the RetVal. |
| if (!I.getType()->isSized()) return; |
| IRBuilder<> IRBBefore(&I); |
| // Untill we have full dynamic coverage, make sure the retval shadow is 0. |
| Value *Base = getShadowPtrForRetval(&I, IRBBefore); |
| IRBBefore.CreateAlignedStore(getCleanShadow(&I), Base, kShadowTLSAlignment); |
| Instruction *NextInsn = 0; |
| if (CS.isCall()) { |
| NextInsn = I.getNextNode(); |
| } else { |
| BasicBlock *NormalDest = cast<InvokeInst>(&I)->getNormalDest(); |
| if (!NormalDest->getSinglePredecessor()) { |
| // FIXME: this case is tricky, so we are just conservative here. |
| // Perhaps we need to split the edge between this BB and NormalDest, |
| // but a naive attempt to use SplitEdge leads to a crash. |
| setShadow(&I, getCleanShadow(&I)); |
| setOrigin(&I, getCleanOrigin()); |
| return; |
| } |
| NextInsn = NormalDest->getFirstInsertionPt(); |
| assert(NextInsn && |
| "Could not find insertion point for retval shadow load"); |
| } |
| IRBuilder<> IRBAfter(NextInsn); |
| Value *RetvalShadow = |
| IRBAfter.CreateAlignedLoad(getShadowPtrForRetval(&I, IRBAfter), |
| kShadowTLSAlignment, "_msret"); |
| setShadow(&I, RetvalShadow); |
| if (ClTrackOrigins) |
| setOrigin(&I, IRBAfter.CreateLoad(getOriginPtrForRetval(IRBAfter))); |
| } |
| |
| void visitReturnInst(ReturnInst &I) { |
| IRBuilder<> IRB(&I); |
| if (Value *RetVal = I.getReturnValue()) { |
| // Set the shadow for the RetVal. |
| Value *Shadow = getShadow(RetVal); |
| Value *ShadowPtr = getShadowPtrForRetval(RetVal, IRB); |
| DEBUG(dbgs() << "Return: " << *Shadow << "\n" << *ShadowPtr << "\n"); |
| IRB.CreateAlignedStore(Shadow, ShadowPtr, kShadowTLSAlignment); |
| if (ClTrackOrigins) |
| IRB.CreateStore(getOrigin(RetVal), getOriginPtrForRetval(IRB)); |
| } |
| } |
| |
| void visitPHINode(PHINode &I) { |
| IRBuilder<> IRB(&I); |
| ShadowPHINodes.push_back(&I); |
| setShadow(&I, IRB.CreatePHI(getShadowTy(&I), I.getNumIncomingValues(), |
| "_msphi_s")); |
| if (ClTrackOrigins) |
| setOrigin(&I, IRB.CreatePHI(MS.OriginTy, I.getNumIncomingValues(), |
| "_msphi_o")); |
| } |
| |
| void visitAllocaInst(AllocaInst &I) { |
| setShadow(&I, getCleanShadow(&I)); |
| if (!ClPoisonStack) return; |
| IRBuilder<> IRB(I.getNextNode()); |
| uint64_t Size = MS.TD->getTypeAllocSize(I.getAllocatedType()); |
| if (ClPoisonStackWithCall) { |
| IRB.CreateCall2(MS.MsanPoisonStackFn, |
| IRB.CreatePointerCast(&I, IRB.getInt8PtrTy()), |
| ConstantInt::get(MS.IntptrTy, Size)); |
| } else { |
| Value *ShadowBase = getShadowPtr(&I, Type::getInt8PtrTy(*MS.C), IRB); |
| IRB.CreateMemSet(ShadowBase, IRB.getInt8(ClPoisonStackPattern), |
| Size, I.getAlignment()); |
| } |
| |
| if (ClTrackOrigins) { |
| setOrigin(&I, getCleanOrigin()); |
| SmallString<2048> StackDescriptionStorage; |
| raw_svector_ostream StackDescription(StackDescriptionStorage); |
| // We create a string with a description of the stack allocation and |
| // pass it into __msan_set_alloca_origin. |
| // It will be printed by the run-time if stack-originated UMR is found. |
| // The first 4 bytes of the string are set to '----' and will be replaced |
| // by __msan_va_arg_overflow_size_tls at the first call. |
| StackDescription << "----" << I.getName() << "@" << F.getName(); |
| Value *Descr = |
| createPrivateNonConstGlobalForString(*F.getParent(), |
| StackDescription.str()); |
| IRB.CreateCall3(MS.MsanSetAllocaOriginFn, |
| IRB.CreatePointerCast(&I, IRB.getInt8PtrTy()), |
| ConstantInt::get(MS.IntptrTy, Size), |
| IRB.CreatePointerCast(Descr, IRB.getInt8PtrTy())); |
| } |
| } |
| |
| void visitSelectInst(SelectInst& I) { |
| IRBuilder<> IRB(&I); |
| setShadow(&I, IRB.CreateSelect(I.getCondition(), |
| getShadow(I.getTrueValue()), getShadow(I.getFalseValue()), |
| "_msprop")); |
| if (ClTrackOrigins) |
| setOrigin(&I, IRB.CreateSelect(I.getCondition(), |
| getOrigin(I.getTrueValue()), getOrigin(I.getFalseValue()))); |
| } |
| |
| void visitLandingPadInst(LandingPadInst &I) { |
| // Do nothing. |
| // See http://code.google.com/p/memory-sanitizer/issues/detail?id=1 |
| setShadow(&I, getCleanShadow(&I)); |
| setOrigin(&I, getCleanOrigin()); |
| } |
| |
| void visitGetElementPtrInst(GetElementPtrInst &I) { |
| handleShadowOr(I); |
| } |
| |
| void visitExtractValueInst(ExtractValueInst &I) { |
| IRBuilder<> IRB(&I); |
| Value *Agg = I.getAggregateOperand(); |
| DEBUG(dbgs() << "ExtractValue: " << I << "\n"); |
| Value *AggShadow = getShadow(Agg); |
| DEBUG(dbgs() << " AggShadow: " << *AggShadow << "\n"); |
| Value *ResShadow = IRB.CreateExtractValue(AggShadow, I.getIndices()); |
| DEBUG(dbgs() << " ResShadow: " << *ResShadow << "\n"); |
| setShadow(&I, ResShadow); |
| setOrigin(&I, getCleanOrigin()); |
| } |
| |
| void visitInsertValueInst(InsertValueInst &I) { |
| IRBuilder<> IRB(&I); |
| DEBUG(dbgs() << "InsertValue: " << I << "\n"); |
| Value *AggShadow = getShadow(I.getAggregateOperand()); |
| Value *InsShadow = getShadow(I.getInsertedValueOperand()); |
| DEBUG(dbgs() << " AggShadow: " << *AggShadow << "\n"); |
| DEBUG(dbgs() << " InsShadow: " << *InsShadow << "\n"); |
| Value *Res = IRB.CreateInsertValue(AggShadow, InsShadow, I.getIndices()); |
| DEBUG(dbgs() << " Res: " << *Res << "\n"); |
| setShadow(&I, Res); |
| setOrigin(&I, getCleanOrigin()); |
| } |
| |
| void dumpInst(Instruction &I) { |
| if (CallInst *CI = dyn_cast<CallInst>(&I)) { |
| errs() << "ZZZ call " << CI->getCalledFunction()->getName() << "\n"; |
| } else { |
| errs() << "ZZZ " << I.getOpcodeName() << "\n"; |
| } |
| errs() << "QQQ " << I << "\n"; |
| } |
| |
| void visitResumeInst(ResumeInst &I) { |
| DEBUG(dbgs() << "Resume: " << I << "\n"); |
| // Nothing to do here. |
| } |
| |
| void visitInstruction(Instruction &I) { |
| // Everything else: stop propagating and check for poisoned shadow. |
| if (ClDumpStrictInstructions) |
| dumpInst(I); |
| DEBUG(dbgs() << "DEFAULT: " << I << "\n"); |
| for (size_t i = 0, n = I.getNumOperands(); i < n; i++) |
| insertCheck(I.getOperand(i), &I); |
| setShadow(&I, getCleanShadow(&I)); |
| setOrigin(&I, getCleanOrigin()); |
| } |
| }; |
| |
| /// \brief AMD64-specific implementation of VarArgHelper. |
| struct VarArgAMD64Helper : public VarArgHelper { |
| // An unfortunate workaround for asymmetric lowering of va_arg stuff. |
| // See a comment in visitCallSite for more details. |
| static const unsigned AMD64GpEndOffset = 48; // AMD64 ABI Draft 0.99.6 p3.5.7 |
| static const unsigned AMD64FpEndOffset = 176; |
| |
| Function &F; |
| MemorySanitizer &MS; |
| MemorySanitizerVisitor &MSV; |
| Value *VAArgTLSCopy; |
| Value *VAArgOverflowSize; |
| |
| SmallVector<CallInst*, 16> VAStartInstrumentationList; |
| |
| VarArgAMD64Helper(Function &F, MemorySanitizer &MS, |
| MemorySanitizerVisitor &MSV) |
| : F(F), MS(MS), MSV(MSV), VAArgTLSCopy(0), VAArgOverflowSize(0) { } |
| |
| enum ArgKind { AK_GeneralPurpose, AK_FloatingPoint, AK_Memory }; |
| |
| ArgKind classifyArgument(Value* arg) { |
| // A very rough approximation of X86_64 argument classification rules. |
| Type *T = arg->getType(); |
| if (T->isFPOrFPVectorTy() || T->isX86_MMXTy()) |
| return AK_FloatingPoint; |
| if (T->isIntegerTy() && T->getPrimitiveSizeInBits() <= 64) |
| return AK_GeneralPurpose; |
| if (T->isPointerTy()) |
| return AK_GeneralPurpose; |
| return AK_Memory; |
| } |
| |
| // For VarArg functions, store the argument shadow in an ABI-specific format |
| // that corresponds to va_list layout. |
| // We do this because Clang lowers va_arg in the frontend, and this pass |
| // only sees the low level code that deals with va_list internals. |
| // A much easier alternative (provided that Clang emits va_arg instructions) |
| // would have been to associate each live instance of va_list with a copy of |
| // MSanParamTLS, and extract shadow on va_arg() call in the argument list |
| // order. |
| void visitCallSite(CallSite &CS, IRBuilder<> &IRB) { |
| unsigned GpOffset = 0; |
| unsigned FpOffset = AMD64GpEndOffset; |
| unsigned OverflowOffset = AMD64FpEndOffset; |
| for (CallSite::arg_iterator ArgIt = CS.arg_begin(), End = CS.arg_end(); |
| ArgIt != End; ++ArgIt) { |
| Value *A = *ArgIt; |
| ArgKind AK = classifyArgument(A); |
| if (AK == AK_GeneralPurpose && GpOffset >= AMD64GpEndOffset) |
| AK = AK_Memory; |
| if (AK == AK_FloatingPoint && FpOffset >= AMD64FpEndOffset) |
| AK = AK_Memory; |
| Value *Base; |
| switch (AK) { |
| case AK_GeneralPurpose: |
| Base = getShadowPtrForVAArgument(A, IRB, GpOffset); |
| GpOffset += 8; |
| break; |
| case AK_FloatingPoint: |
| Base = getShadowPtrForVAArgument(A, IRB, FpOffset); |
| FpOffset += 16; |
| break; |
| case AK_Memory: |
| uint64_t ArgSize = MS.TD->getTypeAllocSize(A->getType()); |
| Base = getShadowPtrForVAArgument(A, IRB, OverflowOffset); |
| OverflowOffset += DataLayout::RoundUpAlignment(ArgSize, 8); |
| } |
| IRB.CreateAlignedStore(MSV.getShadow(A), Base, kShadowTLSAlignment); |
| } |
| Constant *OverflowSize = |
| ConstantInt::get(IRB.getInt64Ty(), OverflowOffset - AMD64FpEndOffset); |
| IRB.CreateStore(OverflowSize, MS.VAArgOverflowSizeTLS); |
| } |
| |
| /// \brief Compute the shadow address for a given va_arg. |
| Value *getShadowPtrForVAArgument(Value *A, IRBuilder<> &IRB, |
| int ArgOffset) { |
| Value *Base = IRB.CreatePointerCast(MS.VAArgTLS, MS.IntptrTy); |
| Base = IRB.CreateAdd(Base, ConstantInt::get(MS.IntptrTy, ArgOffset)); |
| return IRB.CreateIntToPtr(Base, PointerType::get(MSV.getShadowTy(A), 0), |
| "_msarg"); |
| } |
| |
| void visitVAStartInst(VAStartInst &I) { |
| IRBuilder<> IRB(&I); |
| VAStartInstrumentationList.push_back(&I); |
| Value *VAListTag = I.getArgOperand(0); |
| Value *ShadowPtr = MSV.getShadowPtr(VAListTag, IRB.getInt8Ty(), IRB); |
| |
| // Unpoison the whole __va_list_tag. |
| // FIXME: magic ABI constants. |
| IRB.CreateMemSet(ShadowPtr, Constant::getNullValue(IRB.getInt8Ty()), |
| /* size */24, /* alignment */16, false); |
| } |
| |
| void visitVACopyInst(VACopyInst &I) { |
| IRBuilder<> IRB(&I); |
| Value *VAListTag = I.getArgOperand(0); |
| Value *ShadowPtr = MSV.getShadowPtr(VAListTag, IRB.getInt8Ty(), IRB); |
| |
| // Unpoison the whole __va_list_tag. |
| // FIXME: magic ABI constants. |
| IRB.CreateMemSet(ShadowPtr, Constant::getNullValue(IRB.getInt8Ty()), |
| /* size */ 24, /* alignment */ 16, false); |
| } |
| |
| void finalizeInstrumentation() { |
| assert(!VAArgOverflowSize && !VAArgTLSCopy && |
| "finalizeInstrumentation called twice"); |
| if (!VAStartInstrumentationList.empty()) { |
| // If there is a va_start in this function, make a backup copy of |
| // va_arg_tls somewhere in the function entry block. |
| IRBuilder<> IRB(F.getEntryBlock().getFirstNonPHI()); |
| VAArgOverflowSize = IRB.CreateLoad(MS.VAArgOverflowSizeTLS); |
| Value *CopySize = |
| IRB.CreateAdd(ConstantInt::get(MS.IntptrTy, AMD64FpEndOffset), |
| VAArgOverflowSize); |
| VAArgTLSCopy = IRB.CreateAlloca(Type::getInt8Ty(*MS.C), CopySize); |
| IRB.CreateMemCpy(VAArgTLSCopy, MS.VAArgTLS, CopySize, 8); |
| } |
| |
| // Instrument va_start. |
| // Copy va_list shadow from the backup copy of the TLS contents. |
| for (size_t i = 0, n = VAStartInstrumentationList.size(); i < n; i++) { |
| CallInst *OrigInst = VAStartInstrumentationList[i]; |
| IRBuilder<> IRB(OrigInst->getNextNode()); |
| Value *VAListTag = OrigInst->getArgOperand(0); |
| |
| Value *RegSaveAreaPtrPtr = |
| IRB.CreateIntToPtr( |
| IRB.CreateAdd(IRB.CreatePtrToInt(VAListTag, MS.IntptrTy), |
| ConstantInt::get(MS.IntptrTy, 16)), |
| Type::getInt64PtrTy(*MS.C)); |
| Value *RegSaveAreaPtr = IRB.CreateLoad(RegSaveAreaPtrPtr); |
| Value *RegSaveAreaShadowPtr = |
| MSV.getShadowPtr(RegSaveAreaPtr, IRB.getInt8Ty(), IRB); |
| IRB.CreateMemCpy(RegSaveAreaShadowPtr, VAArgTLSCopy, |
| AMD64FpEndOffset, 16); |
| |
| Value *OverflowArgAreaPtrPtr = |
| IRB.CreateIntToPtr( |
| IRB.CreateAdd(IRB.CreatePtrToInt(VAListTag, MS.IntptrTy), |
| ConstantInt::get(MS.IntptrTy, 8)), |
| Type::getInt64PtrTy(*MS.C)); |
| Value *OverflowArgAreaPtr = IRB.CreateLoad(OverflowArgAreaPtrPtr); |
| Value *OverflowArgAreaShadowPtr = |
| MSV.getShadowPtr(OverflowArgAreaPtr, IRB.getInt8Ty(), IRB); |
| Value *SrcPtr = |
| getShadowPtrForVAArgument(VAArgTLSCopy, IRB, AMD64FpEndOffset); |
| IRB.CreateMemCpy(OverflowArgAreaShadowPtr, SrcPtr, VAArgOverflowSize, 16); |
| } |
| } |
| }; |
| |
| VarArgHelper* CreateVarArgHelper(Function &Func, MemorySanitizer &Msan, |
| MemorySanitizerVisitor &Visitor) { |
| return new VarArgAMD64Helper(Func, Msan, Visitor); |
| } |
| |
| } // namespace |
| |
| bool MemorySanitizer::runOnFunction(Function &F) { |
| MemorySanitizerVisitor Visitor(F, *this); |
| |
| // Clear out readonly/readnone attributes. |
| AttrBuilder B; |
| B.addAttribute(Attribute::ReadOnly) |
| .addAttribute(Attribute::ReadNone); |
| F.removeAttribute(AttributeSet::FunctionIndex, |
| Attribute::get(F.getContext(), B)); |
| |
| return Visitor.runOnFunction(); |
| } |