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Diffstat (limited to 'contrib/llvm/lib/Transforms/Instrumentation/ThreadSanitizer.cpp')
| -rw-r--r-- | contrib/llvm/lib/Transforms/Instrumentation/ThreadSanitizer.cpp | 733 |
1 files changed, 0 insertions, 733 deletions
diff --git a/contrib/llvm/lib/Transforms/Instrumentation/ThreadSanitizer.cpp b/contrib/llvm/lib/Transforms/Instrumentation/ThreadSanitizer.cpp deleted file mode 100644 index 5be13fa745cb..000000000000 --- a/contrib/llvm/lib/Transforms/Instrumentation/ThreadSanitizer.cpp +++ /dev/null @@ -1,733 +0,0 @@ -//===-- 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/Transforms/Utils/Local.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/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/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 { - ThreadSanitizer(Module &M); - bool sanitizeFunction(Function &F, const TargetLibraryInfo &TLI); - -private: - void initializeCallbacks(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; - IntegerType *OrdTy; - // Callbacks to run-time library are computed in doInitialization. - 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; - Function *TsanCtorFunction; -}; - -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; -}; -} // namespace - -PreservedAnalyses ThreadSanitizerPass::run(Function &F, - FunctionAnalysisManager &FAM) { - ThreadSanitizer TSan(*F.getParent()); - if (TSan.sanitizeFunction(F, FAM.getResult<TargetLibraryAnalysis>(F))) - return PreservedAnalyses::none(); - return PreservedAnalyses::all(); -} - -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) { - TSan.emplace(M); - return true; -} - -bool ThreadSanitizerLegacyPass::runOnFunction(Function &F) { - auto &TLI = getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(); - TSan->sanitizeFunction(F, TLI); - return true; -} - -FunctionPass *llvm::createThreadSanitizerLegacyPassPass() { - return new ThreadSanitizerLegacyPass(); -} - -void ThreadSanitizer::initializeCallbacks(Module &M) { - 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()); - 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); -} - -ThreadSanitizer::ThreadSanitizer(Module &M) { - const DataLayout &DL = M.getDataLayout(); - IntptrTy = DL.getIntPtrType(M.getContext()); - std::tie(TsanCtorFunction, std::ignore) = - 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); - }); -} - -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 == TsanCtorFunction) - return false; - initializeCallbacks(*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; -} |