| //===-- ThreadSanitizer.cpp - race detector -------------------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file is a part of ThreadSanitizer, a race detector. |
| // |
| // The tool is under development, for the details about previous versions see |
| // http://code.google.com/p/data-race-test |
| // |
| // The instrumentation phase is quite simple: |
| // - Insert calls to run-time library before every memory access. |
| // - Optimizations may apply to avoid instrumenting some of the accesses. |
| // - Insert calls at function entry/exit. |
| // The rest is handled by the run-time library. |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/Transforms/Instrumentation/ThreadSanitizer.h" |
| #include "llvm/ADT/SmallPtrSet.h" |
| #include "llvm/ADT/SmallString.h" |
| #include "llvm/ADT/SmallVector.h" |
| #include "llvm/ADT/Statistic.h" |
| #include "llvm/ADT/StringExtras.h" |
| #include "llvm/Analysis/CaptureTracking.h" |
| #include "llvm/Analysis/TargetLibraryInfo.h" |
| #include "llvm/Analysis/ValueTracking.h" |
| #include "llvm/IR/DataLayout.h" |
| #include "llvm/IR/Function.h" |
| #include "llvm/IR/IRBuilder.h" |
| #include "llvm/IR/IntrinsicInst.h" |
| #include "llvm/IR/Intrinsics.h" |
| #include "llvm/IR/LLVMContext.h" |
| #include "llvm/IR/Metadata.h" |
| #include "llvm/IR/Module.h" |
| #include "llvm/IR/Type.h" |
| #include "llvm/InitializePasses.h" |
| #include "llvm/ProfileData/InstrProf.h" |
| #include "llvm/Support/CommandLine.h" |
| #include "llvm/Support/Debug.h" |
| #include "llvm/Support/MathExtras.h" |
| #include "llvm/Support/raw_ostream.h" |
| #include "llvm/Transforms/Instrumentation.h" |
| #include "llvm/Transforms/Utils/BasicBlockUtils.h" |
| #include "llvm/Transforms/Utils/EscapeEnumerator.h" |
| #include "llvm/Transforms/Utils/Local.h" |
| #include "llvm/Transforms/Utils/ModuleUtils.h" |
| |
| using namespace llvm; |
| |
| #define DEBUG_TYPE "tsan" |
| |
| static cl::opt<bool> ClInstrumentMemoryAccesses( |
| "tsan-instrument-memory-accesses", cl::init(true), |
| cl::desc("Instrument memory accesses"), cl::Hidden); |
| static cl::opt<bool> ClInstrumentFuncEntryExit( |
| "tsan-instrument-func-entry-exit", cl::init(true), |
| cl::desc("Instrument function entry and exit"), cl::Hidden); |
| static cl::opt<bool> ClHandleCxxExceptions( |
| "tsan-handle-cxx-exceptions", cl::init(true), |
| cl::desc("Handle C++ exceptions (insert cleanup blocks for unwinding)"), |
| cl::Hidden); |
| static cl::opt<bool> ClInstrumentAtomics( |
| "tsan-instrument-atomics", cl::init(true), |
| cl::desc("Instrument atomics"), cl::Hidden); |
| static cl::opt<bool> ClInstrumentMemIntrinsics( |
| "tsan-instrument-memintrinsics", cl::init(true), |
| cl::desc("Instrument memintrinsics (memset/memcpy/memmove)"), cl::Hidden); |
| |
| STATISTIC(NumInstrumentedReads, "Number of instrumented reads"); |
| STATISTIC(NumInstrumentedWrites, "Number of instrumented writes"); |
| STATISTIC(NumOmittedReadsBeforeWrite, |
| "Number of reads ignored due to following writes"); |
| STATISTIC(NumAccessesWithBadSize, "Number of accesses with bad size"); |
| STATISTIC(NumInstrumentedVtableWrites, "Number of vtable ptr writes"); |
| STATISTIC(NumInstrumentedVtableReads, "Number of vtable ptr reads"); |
| STATISTIC(NumOmittedReadsFromConstantGlobals, |
| "Number of reads from constant globals"); |
| STATISTIC(NumOmittedReadsFromVtable, "Number of vtable reads"); |
| STATISTIC(NumOmittedNonCaptured, "Number of accesses ignored due to capturing"); |
| |
| static const char *const kTsanModuleCtorName = "tsan.module_ctor"; |
| static const char *const kTsanInitName = "__tsan_init"; |
| |
| namespace { |
| |
| /// ThreadSanitizer: instrument the code in module to find races. |
| /// |
| /// Instantiating ThreadSanitizer inserts the tsan runtime library API function |
| /// declarations into the module if they don't exist already. Instantiating |
| /// ensures the __tsan_init function is in the list of global constructors for |
| /// the module. |
| struct ThreadSanitizer { |
| bool sanitizeFunction(Function &F, const TargetLibraryInfo &TLI); |
| |
| private: |
| void initialize(Module &M); |
| bool instrumentLoadOrStore(Instruction *I, const DataLayout &DL); |
| bool instrumentAtomic(Instruction *I, const DataLayout &DL); |
| bool instrumentMemIntrinsic(Instruction *I); |
| void chooseInstructionsToInstrument(SmallVectorImpl<Instruction *> &Local, |
| SmallVectorImpl<Instruction *> &All, |
| const DataLayout &DL); |
| bool addrPointsToConstantData(Value *Addr); |
| int getMemoryAccessFuncIndex(Value *Addr, const DataLayout &DL); |
| void InsertRuntimeIgnores(Function &F); |
| |
| Type *IntptrTy; |
| FunctionCallee TsanFuncEntry; |
| FunctionCallee TsanFuncExit; |
| FunctionCallee TsanIgnoreBegin; |
| FunctionCallee TsanIgnoreEnd; |
| // Accesses sizes are powers of two: 1, 2, 4, 8, 16. |
| static const size_t kNumberOfAccessSizes = 5; |
| FunctionCallee TsanRead[kNumberOfAccessSizes]; |
| FunctionCallee TsanWrite[kNumberOfAccessSizes]; |
| FunctionCallee TsanUnalignedRead[kNumberOfAccessSizes]; |
| FunctionCallee TsanUnalignedWrite[kNumberOfAccessSizes]; |
| FunctionCallee TsanAtomicLoad[kNumberOfAccessSizes]; |
| FunctionCallee TsanAtomicStore[kNumberOfAccessSizes]; |
| FunctionCallee TsanAtomicRMW[AtomicRMWInst::LAST_BINOP + 1] |
| [kNumberOfAccessSizes]; |
| FunctionCallee TsanAtomicCAS[kNumberOfAccessSizes]; |
| FunctionCallee TsanAtomicThreadFence; |
| FunctionCallee TsanAtomicSignalFence; |
| FunctionCallee TsanVptrUpdate; |
| FunctionCallee TsanVptrLoad; |
| FunctionCallee MemmoveFn, MemcpyFn, MemsetFn; |
| }; |
| |
| struct ThreadSanitizerLegacyPass : FunctionPass { |
| ThreadSanitizerLegacyPass() : FunctionPass(ID) {} |
| StringRef getPassName() const override; |
| void getAnalysisUsage(AnalysisUsage &AU) const override; |
| bool runOnFunction(Function &F) override; |
| bool doInitialization(Module &M) override; |
| static char ID; // Pass identification, replacement for typeid. |
| private: |
| Optional<ThreadSanitizer> TSan; |
| }; |
| |
| void insertModuleCtor(Module &M) { |
| getOrCreateSanitizerCtorAndInitFunctions( |
| M, kTsanModuleCtorName, kTsanInitName, /*InitArgTypes=*/{}, |
| /*InitArgs=*/{}, |
| // This callback is invoked when the functions are created the first |
| // time. Hook them into the global ctors list in that case: |
| [&](Function *Ctor, FunctionCallee) { appendToGlobalCtors(M, Ctor, 0); }); |
| } |
| |
| } // namespace |
| |
| PreservedAnalyses ThreadSanitizerPass::run(Function &F, |
| FunctionAnalysisManager &FAM) { |
| ThreadSanitizer TSan; |
| if (TSan.sanitizeFunction(F, FAM.getResult<TargetLibraryAnalysis>(F))) |
| return PreservedAnalyses::none(); |
| return PreservedAnalyses::all(); |
| } |
| |
| PreservedAnalyses ThreadSanitizerPass::run(Module &M, |
| ModuleAnalysisManager &MAM) { |
| insertModuleCtor(M); |
| return PreservedAnalyses::none(); |
| } |
| |
| char ThreadSanitizerLegacyPass::ID = 0; |
| INITIALIZE_PASS_BEGIN(ThreadSanitizerLegacyPass, "tsan", |
| "ThreadSanitizer: detects data races.", false, false) |
| INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass) |
| INITIALIZE_PASS_END(ThreadSanitizerLegacyPass, "tsan", |
| "ThreadSanitizer: detects data races.", false, false) |
| |
| StringRef ThreadSanitizerLegacyPass::getPassName() const { |
| return "ThreadSanitizerLegacyPass"; |
| } |
| |
| void ThreadSanitizerLegacyPass::getAnalysisUsage(AnalysisUsage &AU) const { |
| AU.addRequired<TargetLibraryInfoWrapperPass>(); |
| } |
| |
| bool ThreadSanitizerLegacyPass::doInitialization(Module &M) { |
| insertModuleCtor(M); |
| TSan.emplace(); |
| return true; |
| } |
| |
| bool ThreadSanitizerLegacyPass::runOnFunction(Function &F) { |
| auto &TLI = getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(F); |
| TSan->sanitizeFunction(F, TLI); |
| return true; |
| } |
| |
| FunctionPass *llvm::createThreadSanitizerLegacyPassPass() { |
| return new ThreadSanitizerLegacyPass(); |
| } |
| |
| void ThreadSanitizer::initialize(Module &M) { |
| const DataLayout &DL = M.getDataLayout(); |
| IntptrTy = DL.getIntPtrType(M.getContext()); |
| |
| IRBuilder<> IRB(M.getContext()); |
| AttributeList Attr; |
| Attr = Attr.addAttribute(M.getContext(), AttributeList::FunctionIndex, |
| Attribute::NoUnwind); |
| // Initialize the callbacks. |
| TsanFuncEntry = M.getOrInsertFunction("__tsan_func_entry", Attr, |
| IRB.getVoidTy(), IRB.getInt8PtrTy()); |
| TsanFuncExit = |
| M.getOrInsertFunction("__tsan_func_exit", Attr, IRB.getVoidTy()); |
| TsanIgnoreBegin = M.getOrInsertFunction("__tsan_ignore_thread_begin", Attr, |
| IRB.getVoidTy()); |
| TsanIgnoreEnd = |
| M.getOrInsertFunction("__tsan_ignore_thread_end", Attr, IRB.getVoidTy()); |
| IntegerType *OrdTy = IRB.getInt32Ty(); |
| for (size_t i = 0; i < kNumberOfAccessSizes; ++i) { |
| const unsigned ByteSize = 1U << i; |
| const unsigned BitSize = ByteSize * 8; |
| std::string ByteSizeStr = utostr(ByteSize); |
| std::string BitSizeStr = utostr(BitSize); |
| SmallString<32> ReadName("__tsan_read" + ByteSizeStr); |
| TsanRead[i] = M.getOrInsertFunction(ReadName, Attr, IRB.getVoidTy(), |
| IRB.getInt8PtrTy()); |
| |
| SmallString<32> WriteName("__tsan_write" + ByteSizeStr); |
| TsanWrite[i] = M.getOrInsertFunction(WriteName, Attr, IRB.getVoidTy(), |
| IRB.getInt8PtrTy()); |
| |
| SmallString<64> UnalignedReadName("__tsan_unaligned_read" + ByteSizeStr); |
| TsanUnalignedRead[i] = M.getOrInsertFunction( |
| UnalignedReadName, Attr, IRB.getVoidTy(), IRB.getInt8PtrTy()); |
| |
| SmallString<64> UnalignedWriteName("__tsan_unaligned_write" + ByteSizeStr); |
| TsanUnalignedWrite[i] = M.getOrInsertFunction( |
| UnalignedWriteName, Attr, IRB.getVoidTy(), IRB.getInt8PtrTy()); |
| |
| Type *Ty = Type::getIntNTy(M.getContext(), BitSize); |
| Type *PtrTy = Ty->getPointerTo(); |
| SmallString<32> AtomicLoadName("__tsan_atomic" + BitSizeStr + "_load"); |
| TsanAtomicLoad[i] = |
| M.getOrInsertFunction(AtomicLoadName, Attr, Ty, PtrTy, OrdTy); |
| |
| SmallString<32> AtomicStoreName("__tsan_atomic" + BitSizeStr + "_store"); |
| TsanAtomicStore[i] = M.getOrInsertFunction( |
| AtomicStoreName, Attr, IRB.getVoidTy(), PtrTy, Ty, OrdTy); |
| |
| for (int op = AtomicRMWInst::FIRST_BINOP; |
| op <= AtomicRMWInst::LAST_BINOP; ++op) { |
| TsanAtomicRMW[op][i] = nullptr; |
| const char *NamePart = nullptr; |
| if (op == AtomicRMWInst::Xchg) |
| NamePart = "_exchange"; |
| else if (op == AtomicRMWInst::Add) |
| NamePart = "_fetch_add"; |
| else if (op == AtomicRMWInst::Sub) |
| NamePart = "_fetch_sub"; |
| else if (op == AtomicRMWInst::And) |
| NamePart = "_fetch_and"; |
| else if (op == AtomicRMWInst::Or) |
| NamePart = "_fetch_or"; |
| else if (op == AtomicRMWInst::Xor) |
| NamePart = "_fetch_xor"; |
| else if (op == AtomicRMWInst::Nand) |
| NamePart = "_fetch_nand"; |
| else |
| continue; |
| SmallString<32> RMWName("__tsan_atomic" + itostr(BitSize) + NamePart); |
| TsanAtomicRMW[op][i] = |
| M.getOrInsertFunction(RMWName, Attr, Ty, PtrTy, Ty, OrdTy); |
| } |
| |
| SmallString<32> AtomicCASName("__tsan_atomic" + BitSizeStr + |
| "_compare_exchange_val"); |
| TsanAtomicCAS[i] = M.getOrInsertFunction(AtomicCASName, Attr, Ty, PtrTy, Ty, |
| Ty, OrdTy, OrdTy); |
| } |
| TsanVptrUpdate = |
| M.getOrInsertFunction("__tsan_vptr_update", Attr, IRB.getVoidTy(), |
| IRB.getInt8PtrTy(), IRB.getInt8PtrTy()); |
| TsanVptrLoad = M.getOrInsertFunction("__tsan_vptr_read", Attr, |
| IRB.getVoidTy(), IRB.getInt8PtrTy()); |
| TsanAtomicThreadFence = M.getOrInsertFunction("__tsan_atomic_thread_fence", |
| Attr, IRB.getVoidTy(), OrdTy); |
| TsanAtomicSignalFence = M.getOrInsertFunction("__tsan_atomic_signal_fence", |
| Attr, IRB.getVoidTy(), OrdTy); |
| |
| MemmoveFn = |
| M.getOrInsertFunction("memmove", Attr, IRB.getInt8PtrTy(), |
| IRB.getInt8PtrTy(), IRB.getInt8PtrTy(), IntptrTy); |
| MemcpyFn = |
| M.getOrInsertFunction("memcpy", Attr, IRB.getInt8PtrTy(), |
| IRB.getInt8PtrTy(), IRB.getInt8PtrTy(), IntptrTy); |
| MemsetFn = |
| M.getOrInsertFunction("memset", Attr, IRB.getInt8PtrTy(), |
| IRB.getInt8PtrTy(), IRB.getInt32Ty(), IntptrTy); |
| } |
| |
| static bool isVtableAccess(Instruction *I) { |
| if (MDNode *Tag = I->getMetadata(LLVMContext::MD_tbaa)) |
| return Tag->isTBAAVtableAccess(); |
| return false; |
| } |
| |
| // Do not instrument known races/"benign races" that come from compiler |
| // instrumentatin. The user has no way of suppressing them. |
| static bool shouldInstrumentReadWriteFromAddress(const Module *M, Value *Addr) { |
| // Peel off GEPs and BitCasts. |
| Addr = Addr->stripInBoundsOffsets(); |
| |
| if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Addr)) { |
| if (GV->hasSection()) { |
| StringRef SectionName = GV->getSection(); |
| // Check if the global is in the PGO counters section. |
| auto OF = Triple(M->getTargetTriple()).getObjectFormat(); |
| if (SectionName.endswith( |
| getInstrProfSectionName(IPSK_cnts, OF, /*AddSegmentInfo=*/false))) |
| return false; |
| } |
| |
| // Check if the global is private gcov data. |
| if (GV->getName().startswith("__llvm_gcov") || |
| GV->getName().startswith("__llvm_gcda")) |
| return false; |
| } |
| |
| // Do not instrument acesses from different address spaces; we cannot deal |
| // with them. |
| if (Addr) { |
| Type *PtrTy = cast<PointerType>(Addr->getType()->getScalarType()); |
| if (PtrTy->getPointerAddressSpace() != 0) |
| return false; |
| } |
| |
| return true; |
| } |
| |
| bool ThreadSanitizer::addrPointsToConstantData(Value *Addr) { |
| // If this is a GEP, just analyze its pointer operand. |
| if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Addr)) |
| Addr = GEP->getPointerOperand(); |
| |
| if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Addr)) { |
| if (GV->isConstant()) { |
| // Reads from constant globals can not race with any writes. |
| NumOmittedReadsFromConstantGlobals++; |
| return true; |
| } |
| } else if (LoadInst *L = dyn_cast<LoadInst>(Addr)) { |
| if (isVtableAccess(L)) { |
| // Reads from a vtable pointer can not race with any writes. |
| NumOmittedReadsFromVtable++; |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| // Instrumenting some of the accesses may be proven redundant. |
| // Currently handled: |
| // - read-before-write (within same BB, no calls between) |
| // - not captured variables |
| // |
| // We do not handle some of the patterns that should not survive |
| // after the classic compiler optimizations. |
| // E.g. two reads from the same temp should be eliminated by CSE, |
| // two writes should be eliminated by DSE, etc. |
| // |
| // 'Local' is a vector of insns within the same BB (no calls between). |
| // 'All' is a vector of insns that will be instrumented. |
| void ThreadSanitizer::chooseInstructionsToInstrument( |
| SmallVectorImpl<Instruction *> &Local, SmallVectorImpl<Instruction *> &All, |
| const DataLayout &DL) { |
| SmallPtrSet<Value*, 8> WriteTargets; |
| // Iterate from the end. |
| for (Instruction *I : reverse(Local)) { |
| if (StoreInst *Store = dyn_cast<StoreInst>(I)) { |
| Value *Addr = Store->getPointerOperand(); |
| if (!shouldInstrumentReadWriteFromAddress(I->getModule(), Addr)) |
| continue; |
| WriteTargets.insert(Addr); |
| } else { |
| LoadInst *Load = cast<LoadInst>(I); |
| Value *Addr = Load->getPointerOperand(); |
| if (!shouldInstrumentReadWriteFromAddress(I->getModule(), Addr)) |
| continue; |
| if (WriteTargets.count(Addr)) { |
| // We will write to this temp, so no reason to analyze the read. |
| NumOmittedReadsBeforeWrite++; |
| continue; |
| } |
| if (addrPointsToConstantData(Addr)) { |
| // Addr points to some constant data -- it can not race with any writes. |
| continue; |
| } |
| } |
| Value *Addr = isa<StoreInst>(*I) |
| ? cast<StoreInst>(I)->getPointerOperand() |
| : cast<LoadInst>(I)->getPointerOperand(); |
| if (isa<AllocaInst>(GetUnderlyingObject(Addr, DL)) && |
| !PointerMayBeCaptured(Addr, true, true)) { |
| // The variable is addressable but not captured, so it cannot be |
| // referenced from a different thread and participate in a data race |
| // (see llvm/Analysis/CaptureTracking.h for details). |
| NumOmittedNonCaptured++; |
| continue; |
| } |
| All.push_back(I); |
| } |
| Local.clear(); |
| } |
| |
| static bool isAtomic(Instruction *I) { |
| // TODO: Ask TTI whether synchronization scope is between threads. |
| if (LoadInst *LI = dyn_cast<LoadInst>(I)) |
| return LI->isAtomic() && LI->getSyncScopeID() != SyncScope::SingleThread; |
| if (StoreInst *SI = dyn_cast<StoreInst>(I)) |
| return SI->isAtomic() && SI->getSyncScopeID() != SyncScope::SingleThread; |
| if (isa<AtomicRMWInst>(I)) |
| return true; |
| if (isa<AtomicCmpXchgInst>(I)) |
| return true; |
| if (isa<FenceInst>(I)) |
| return true; |
| return false; |
| } |
| |
| void ThreadSanitizer::InsertRuntimeIgnores(Function &F) { |
| IRBuilder<> IRB(F.getEntryBlock().getFirstNonPHI()); |
| IRB.CreateCall(TsanIgnoreBegin); |
| EscapeEnumerator EE(F, "tsan_ignore_cleanup", ClHandleCxxExceptions); |
| while (IRBuilder<> *AtExit = EE.Next()) { |
| AtExit->CreateCall(TsanIgnoreEnd); |
| } |
| } |
| |
| bool ThreadSanitizer::sanitizeFunction(Function &F, |
| const TargetLibraryInfo &TLI) { |
| // This is required to prevent instrumenting call to __tsan_init from within |
| // the module constructor. |
| if (F.getName() == kTsanModuleCtorName) |
| return false; |
| initialize(*F.getParent()); |
| SmallVector<Instruction*, 8> AllLoadsAndStores; |
| SmallVector<Instruction*, 8> LocalLoadsAndStores; |
| SmallVector<Instruction*, 8> AtomicAccesses; |
| SmallVector<Instruction*, 8> MemIntrinCalls; |
| bool Res = false; |
| bool HasCalls = false; |
| bool SanitizeFunction = F.hasFnAttribute(Attribute::SanitizeThread); |
| const DataLayout &DL = F.getParent()->getDataLayout(); |
| |
| // Traverse all instructions, collect loads/stores/returns, check for calls. |
| for (auto &BB : F) { |
| for (auto &Inst : BB) { |
| if (isAtomic(&Inst)) |
| AtomicAccesses.push_back(&Inst); |
| else if (isa<LoadInst>(Inst) || isa<StoreInst>(Inst)) |
| LocalLoadsAndStores.push_back(&Inst); |
| else if (isa<CallInst>(Inst) || isa<InvokeInst>(Inst)) { |
| if (CallInst *CI = dyn_cast<CallInst>(&Inst)) |
| maybeMarkSanitizerLibraryCallNoBuiltin(CI, &TLI); |
| if (isa<MemIntrinsic>(Inst)) |
| MemIntrinCalls.push_back(&Inst); |
| HasCalls = true; |
| chooseInstructionsToInstrument(LocalLoadsAndStores, AllLoadsAndStores, |
| DL); |
| } |
| } |
| chooseInstructionsToInstrument(LocalLoadsAndStores, AllLoadsAndStores, DL); |
| } |
| |
| // We have collected all loads and stores. |
| // FIXME: many of these accesses do not need to be checked for races |
| // (e.g. variables that do not escape, etc). |
| |
| // Instrument memory accesses only if we want to report bugs in the function. |
| if (ClInstrumentMemoryAccesses && SanitizeFunction) |
| for (auto Inst : AllLoadsAndStores) { |
| Res |= instrumentLoadOrStore(Inst, DL); |
| } |
| |
| // Instrument atomic memory accesses in any case (they can be used to |
| // implement synchronization). |
| if (ClInstrumentAtomics) |
| for (auto Inst : AtomicAccesses) { |
| Res |= instrumentAtomic(Inst, DL); |
| } |
| |
| if (ClInstrumentMemIntrinsics && SanitizeFunction) |
| for (auto Inst : MemIntrinCalls) { |
| Res |= instrumentMemIntrinsic(Inst); |
| } |
| |
| if (F.hasFnAttribute("sanitize_thread_no_checking_at_run_time")) { |
| assert(!F.hasFnAttribute(Attribute::SanitizeThread)); |
| if (HasCalls) |
| InsertRuntimeIgnores(F); |
| } |
| |
| // Instrument function entry/exit points if there were instrumented accesses. |
| if ((Res || HasCalls) && ClInstrumentFuncEntryExit) { |
| IRBuilder<> IRB(F.getEntryBlock().getFirstNonPHI()); |
| Value *ReturnAddress = IRB.CreateCall( |
| Intrinsic::getDeclaration(F.getParent(), Intrinsic::returnaddress), |
| IRB.getInt32(0)); |
| IRB.CreateCall(TsanFuncEntry, ReturnAddress); |
| |
| EscapeEnumerator EE(F, "tsan_cleanup", ClHandleCxxExceptions); |
| while (IRBuilder<> *AtExit = EE.Next()) { |
| AtExit->CreateCall(TsanFuncExit, {}); |
| } |
| Res = true; |
| } |
| return Res; |
| } |
| |
| bool ThreadSanitizer::instrumentLoadOrStore(Instruction *I, |
| const DataLayout &DL) { |
| IRBuilder<> IRB(I); |
| bool IsWrite = isa<StoreInst>(*I); |
| Value *Addr = IsWrite |
| ? cast<StoreInst>(I)->getPointerOperand() |
| : cast<LoadInst>(I)->getPointerOperand(); |
| |
| // swifterror memory addresses are mem2reg promoted by instruction selection. |
| // As such they cannot have regular uses like an instrumentation function and |
| // it makes no sense to track them as memory. |
| if (Addr->isSwiftError()) |
| return false; |
| |
| int Idx = getMemoryAccessFuncIndex(Addr, DL); |
| if (Idx < 0) |
| return false; |
| if (IsWrite && isVtableAccess(I)) { |
| LLVM_DEBUG(dbgs() << " VPTR : " << *I << "\n"); |
| Value *StoredValue = cast<StoreInst>(I)->getValueOperand(); |
| // StoredValue may be a vector type if we are storing several vptrs at once. |
| // In this case, just take the first element of the vector since this is |
| // enough to find vptr races. |
| if (isa<VectorType>(StoredValue->getType())) |
| StoredValue = IRB.CreateExtractElement( |
| StoredValue, ConstantInt::get(IRB.getInt32Ty(), 0)); |
| if (StoredValue->getType()->isIntegerTy()) |
| StoredValue = IRB.CreateIntToPtr(StoredValue, IRB.getInt8PtrTy()); |
| // Call TsanVptrUpdate. |
| IRB.CreateCall(TsanVptrUpdate, |
| {IRB.CreatePointerCast(Addr, IRB.getInt8PtrTy()), |
| IRB.CreatePointerCast(StoredValue, IRB.getInt8PtrTy())}); |
| NumInstrumentedVtableWrites++; |
| return true; |
| } |
| if (!IsWrite && isVtableAccess(I)) { |
| IRB.CreateCall(TsanVptrLoad, |
| IRB.CreatePointerCast(Addr, IRB.getInt8PtrTy())); |
| NumInstrumentedVtableReads++; |
| return true; |
| } |
| const unsigned Alignment = IsWrite |
| ? cast<StoreInst>(I)->getAlignment() |
| : cast<LoadInst>(I)->getAlignment(); |
| Type *OrigTy = cast<PointerType>(Addr->getType())->getElementType(); |
| const uint32_t TypeSize = DL.getTypeStoreSizeInBits(OrigTy); |
| FunctionCallee OnAccessFunc = nullptr; |
| if (Alignment == 0 || Alignment >= 8 || (Alignment % (TypeSize / 8)) == 0) |
| OnAccessFunc = IsWrite ? TsanWrite[Idx] : TsanRead[Idx]; |
| else |
| OnAccessFunc = IsWrite ? TsanUnalignedWrite[Idx] : TsanUnalignedRead[Idx]; |
| IRB.CreateCall(OnAccessFunc, IRB.CreatePointerCast(Addr, IRB.getInt8PtrTy())); |
| if (IsWrite) NumInstrumentedWrites++; |
| else NumInstrumentedReads++; |
| return true; |
| } |
| |
| static ConstantInt *createOrdering(IRBuilder<> *IRB, AtomicOrdering ord) { |
| uint32_t v = 0; |
| switch (ord) { |
| case AtomicOrdering::NotAtomic: |
| llvm_unreachable("unexpected atomic ordering!"); |
| case AtomicOrdering::Unordered: LLVM_FALLTHROUGH; |
| case AtomicOrdering::Monotonic: v = 0; break; |
| // Not specified yet: |
| // case AtomicOrdering::Consume: v = 1; break; |
| case AtomicOrdering::Acquire: v = 2; break; |
| case AtomicOrdering::Release: v = 3; break; |
| case AtomicOrdering::AcquireRelease: v = 4; break; |
| case AtomicOrdering::SequentiallyConsistent: v = 5; break; |
| } |
| return IRB->getInt32(v); |
| } |
| |
| // If a memset intrinsic gets inlined by the code gen, we will miss races on it. |
| // So, we either need to ensure the intrinsic is not inlined, or instrument it. |
| // We do not instrument memset/memmove/memcpy intrinsics (too complicated), |
| // instead we simply replace them with regular function calls, which are then |
| // intercepted by the run-time. |
| // Since tsan is running after everyone else, the calls should not be |
| // replaced back with intrinsics. If that becomes wrong at some point, |
| // we will need to call e.g. __tsan_memset to avoid the intrinsics. |
| bool ThreadSanitizer::instrumentMemIntrinsic(Instruction *I) { |
| IRBuilder<> IRB(I); |
| if (MemSetInst *M = dyn_cast<MemSetInst>(I)) { |
| IRB.CreateCall( |
| MemsetFn, |
| {IRB.CreatePointerCast(M->getArgOperand(0), IRB.getInt8PtrTy()), |
| IRB.CreateIntCast(M->getArgOperand(1), IRB.getInt32Ty(), false), |
| IRB.CreateIntCast(M->getArgOperand(2), IntptrTy, false)}); |
| I->eraseFromParent(); |
| } else if (MemTransferInst *M = dyn_cast<MemTransferInst>(I)) { |
| IRB.CreateCall( |
| isa<MemCpyInst>(M) ? MemcpyFn : MemmoveFn, |
| {IRB.CreatePointerCast(M->getArgOperand(0), IRB.getInt8PtrTy()), |
| IRB.CreatePointerCast(M->getArgOperand(1), IRB.getInt8PtrTy()), |
| IRB.CreateIntCast(M->getArgOperand(2), IntptrTy, false)}); |
| I->eraseFromParent(); |
| } |
| return false; |
| } |
| |
| // Both llvm and ThreadSanitizer atomic operations are based on C++11/C1x |
| // standards. For background see C++11 standard. A slightly older, publicly |
| // available draft of the standard (not entirely up-to-date, but close enough |
| // for casual browsing) is available here: |
| // http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2011/n3242.pdf |
| // The following page contains more background information: |
| // http://www.hpl.hp.com/personal/Hans_Boehm/c++mm/ |
| |
| bool ThreadSanitizer::instrumentAtomic(Instruction *I, const DataLayout &DL) { |
| IRBuilder<> IRB(I); |
| if (LoadInst *LI = dyn_cast<LoadInst>(I)) { |
| Value *Addr = LI->getPointerOperand(); |
| int Idx = getMemoryAccessFuncIndex(Addr, DL); |
| if (Idx < 0) |
| return false; |
| const unsigned ByteSize = 1U << Idx; |
| const unsigned BitSize = ByteSize * 8; |
| Type *Ty = Type::getIntNTy(IRB.getContext(), BitSize); |
| Type *PtrTy = Ty->getPointerTo(); |
| Value *Args[] = {IRB.CreatePointerCast(Addr, PtrTy), |
| createOrdering(&IRB, LI->getOrdering())}; |
| Type *OrigTy = cast<PointerType>(Addr->getType())->getElementType(); |
| Value *C = IRB.CreateCall(TsanAtomicLoad[Idx], Args); |
| Value *Cast = IRB.CreateBitOrPointerCast(C, OrigTy); |
| I->replaceAllUsesWith(Cast); |
| } else if (StoreInst *SI = dyn_cast<StoreInst>(I)) { |
| Value *Addr = SI->getPointerOperand(); |
| int Idx = getMemoryAccessFuncIndex(Addr, DL); |
| if (Idx < 0) |
| return false; |
| const unsigned ByteSize = 1U << Idx; |
| const unsigned BitSize = ByteSize * 8; |
| Type *Ty = Type::getIntNTy(IRB.getContext(), BitSize); |
| Type *PtrTy = Ty->getPointerTo(); |
| Value *Args[] = {IRB.CreatePointerCast(Addr, PtrTy), |
| IRB.CreateBitOrPointerCast(SI->getValueOperand(), Ty), |
| createOrdering(&IRB, SI->getOrdering())}; |
| CallInst *C = CallInst::Create(TsanAtomicStore[Idx], Args); |
| ReplaceInstWithInst(I, C); |
| } else if (AtomicRMWInst *RMWI = dyn_cast<AtomicRMWInst>(I)) { |
| Value *Addr = RMWI->getPointerOperand(); |
| int Idx = getMemoryAccessFuncIndex(Addr, DL); |
| if (Idx < 0) |
| return false; |
| FunctionCallee F = TsanAtomicRMW[RMWI->getOperation()][Idx]; |
| if (!F) |
| return false; |
| const unsigned ByteSize = 1U << Idx; |
| const unsigned BitSize = ByteSize * 8; |
| Type *Ty = Type::getIntNTy(IRB.getContext(), BitSize); |
| Type *PtrTy = Ty->getPointerTo(); |
| Value *Args[] = {IRB.CreatePointerCast(Addr, PtrTy), |
| IRB.CreateIntCast(RMWI->getValOperand(), Ty, false), |
| createOrdering(&IRB, RMWI->getOrdering())}; |
| CallInst *C = CallInst::Create(F, Args); |
| ReplaceInstWithInst(I, C); |
| } else if (AtomicCmpXchgInst *CASI = dyn_cast<AtomicCmpXchgInst>(I)) { |
| Value *Addr = CASI->getPointerOperand(); |
| int Idx = getMemoryAccessFuncIndex(Addr, DL); |
| if (Idx < 0) |
| return false; |
| const unsigned ByteSize = 1U << Idx; |
| const unsigned BitSize = ByteSize * 8; |
| Type *Ty = Type::getIntNTy(IRB.getContext(), BitSize); |
| Type *PtrTy = Ty->getPointerTo(); |
| Value *CmpOperand = |
| IRB.CreateBitOrPointerCast(CASI->getCompareOperand(), Ty); |
| Value *NewOperand = |
| IRB.CreateBitOrPointerCast(CASI->getNewValOperand(), Ty); |
| Value *Args[] = {IRB.CreatePointerCast(Addr, PtrTy), |
| CmpOperand, |
| NewOperand, |
| createOrdering(&IRB, CASI->getSuccessOrdering()), |
| createOrdering(&IRB, CASI->getFailureOrdering())}; |
| CallInst *C = IRB.CreateCall(TsanAtomicCAS[Idx], Args); |
| Value *Success = IRB.CreateICmpEQ(C, CmpOperand); |
| Value *OldVal = C; |
| Type *OrigOldValTy = CASI->getNewValOperand()->getType(); |
| if (Ty != OrigOldValTy) { |
| // The value is a pointer, so we need to cast the return value. |
| OldVal = IRB.CreateIntToPtr(C, OrigOldValTy); |
| } |
| |
| Value *Res = |
| IRB.CreateInsertValue(UndefValue::get(CASI->getType()), OldVal, 0); |
| Res = IRB.CreateInsertValue(Res, Success, 1); |
| |
| I->replaceAllUsesWith(Res); |
| I->eraseFromParent(); |
| } else if (FenceInst *FI = dyn_cast<FenceInst>(I)) { |
| Value *Args[] = {createOrdering(&IRB, FI->getOrdering())}; |
| FunctionCallee F = FI->getSyncScopeID() == SyncScope::SingleThread |
| ? TsanAtomicSignalFence |
| : TsanAtomicThreadFence; |
| CallInst *C = CallInst::Create(F, Args); |
| ReplaceInstWithInst(I, C); |
| } |
| return true; |
| } |
| |
| int ThreadSanitizer::getMemoryAccessFuncIndex(Value *Addr, |
| const DataLayout &DL) { |
| Type *OrigPtrTy = Addr->getType(); |
| Type *OrigTy = cast<PointerType>(OrigPtrTy)->getElementType(); |
| assert(OrigTy->isSized()); |
| uint32_t TypeSize = DL.getTypeStoreSizeInBits(OrigTy); |
| if (TypeSize != 8 && TypeSize != 16 && |
| TypeSize != 32 && TypeSize != 64 && TypeSize != 128) { |
| NumAccessesWithBadSize++; |
| // Ignore all unusual sizes. |
| return -1; |
| } |
| size_t Idx = countTrailingZeros(TypeSize / 8); |
| assert(Idx < kNumberOfAccessSizes); |
| return Idx; |
| } |
