// The rest is handled by the run-time library.
//===----------------------------------------------------------------------===//
-#define DEBUG_TYPE "tsan"
-
+#include "llvm/Transforms/Instrumentation.h"
+#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/StringExtras.h"
-#include "llvm/Intrinsics.h"
-#include "llvm/Function.h"
-#include "llvm/Module.h"
+#include "llvm/Analysis/CaptureTracking.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/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
-#include "llvm/Support/IRBuilder.h"
#include "llvm/Support/MathExtras.h"
-#include "llvm/Target/TargetData.h"
-#include "llvm/Transforms/Instrumentation.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;
+#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> 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.
struct ThreadSanitizer : public FunctionPass {
- ThreadSanitizer();
- bool runOnFunction(Function &F);
- bool doInitialization(Module &M);
- bool instrumentLoadOrStore(Instruction *I);
+ ThreadSanitizer() : FunctionPass(ID) {}
+ const char *getPassName() const override;
+ bool runOnFunction(Function &F) override;
+ bool doInitialization(Module &M) override;
static char ID; // Pass identification, replacement for typeid.
private:
- TargetData *TD;
+ 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);
+
+ Type *IntptrTy;
+ IntegerType *OrdTy;
// Callbacks to run-time library are computed in doInitialization.
- Value *TsanFuncEntry;
- Value *TsanFuncExit;
+ Function *TsanFuncEntry;
+ Function *TsanFuncExit;
// Accesses sizes are powers of two: 1, 2, 4, 8, 16.
static const size_t kNumberOfAccessSizes = 5;
- Value *TsanRead[kNumberOfAccessSizes];
- Value *TsanWrite[kNumberOfAccessSizes];
+ Function *TsanRead[kNumberOfAccessSizes];
+ Function *TsanWrite[kNumberOfAccessSizes];
+ Function *TsanUnalignedRead[kNumberOfAccessSizes];
+ Function *TsanUnalignedWrite[kNumberOfAccessSizes];
+ Function *TsanAtomicLoad[kNumberOfAccessSizes];
+ Function *TsanAtomicStore[kNumberOfAccessSizes];
+ Function *TsanAtomicRMW[AtomicRMWInst::LAST_BINOP + 1][kNumberOfAccessSizes];
+ Function *TsanAtomicCAS[kNumberOfAccessSizes];
+ Function *TsanAtomicThreadFence;
+ Function *TsanAtomicSignalFence;
+ Function *TsanVptrUpdate;
+ Function *TsanVptrLoad;
+ Function *MemmoveFn, *MemcpyFn, *MemsetFn;
+ Function *TsanCtorFunction;
};
} // namespace
"ThreadSanitizer: detects data races.",
false, false)
-ThreadSanitizer::ThreadSanitizer()
- : FunctionPass(ID),
- TD(NULL) {
+const char *ThreadSanitizer::getPassName() const {
+ return "ThreadSanitizer";
}
FunctionPass *llvm::createThreadSanitizerPass() {
return new ThreadSanitizer();
}
-bool ThreadSanitizer::doInitialization(Module &M) {
- TD = getAnalysisIfAvailable<TargetData>();
- if (!TD)
- return false;
- // Always insert a call to __tsan_init into the module's CTORs.
+void ThreadSanitizer::initializeCallbacks(Module &M) {
IRBuilder<> IRB(M.getContext());
- Value *TsanInit = M.getOrInsertFunction("__tsan_init",
- IRB.getVoidTy(), NULL);
- appendToGlobalCtors(M, cast<Function>(TsanInit), 0);
-
// Initialize the callbacks.
- TsanFuncEntry = M.getOrInsertFunction("__tsan_func_entry", IRB.getVoidTy(),
- IRB.getInt8PtrTy(), NULL);
- TsanFuncExit = M.getOrInsertFunction("__tsan_func_exit", IRB.getVoidTy(),
- NULL);
+ TsanFuncEntry = checkSanitizerInterfaceFunction(M.getOrInsertFunction(
+ "__tsan_func_entry", IRB.getVoidTy(), IRB.getInt8PtrTy(), nullptr));
+ TsanFuncExit = checkSanitizerInterfaceFunction(
+ M.getOrInsertFunction("__tsan_func_exit", IRB.getVoidTy(), nullptr));
+ OrdTy = IRB.getInt32Ty();
for (size_t i = 0; i < kNumberOfAccessSizes; ++i) {
- SmallString<32> ReadName("__tsan_read");
- ReadName += itostr(1 << i);
- TsanRead[i] = M.getOrInsertFunction(ReadName, IRB.getVoidTy(),
- IRB.getInt8PtrTy(), NULL);
- SmallString<32> WriteName("__tsan_write");
- WriteName += itostr(1 << i);
- TsanWrite[i] = M.getOrInsertFunction(WriteName, IRB.getVoidTy(),
- IRB.getInt8PtrTy(), NULL);
+ 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] = checkSanitizerInterfaceFunction(M.getOrInsertFunction(
+ ReadName, IRB.getVoidTy(), IRB.getInt8PtrTy(), nullptr));
+
+ SmallString<32> WriteName("__tsan_write" + ByteSizeStr);
+ TsanWrite[i] = checkSanitizerInterfaceFunction(M.getOrInsertFunction(
+ WriteName, IRB.getVoidTy(), IRB.getInt8PtrTy(), nullptr));
+
+ SmallString<64> UnalignedReadName("__tsan_unaligned_read" + ByteSizeStr);
+ TsanUnalignedRead[i] =
+ checkSanitizerInterfaceFunction(M.getOrInsertFunction(
+ UnalignedReadName, IRB.getVoidTy(), IRB.getInt8PtrTy(), nullptr));
+
+ SmallString<64> UnalignedWriteName("__tsan_unaligned_write" + ByteSizeStr);
+ TsanUnalignedWrite[i] =
+ checkSanitizerInterfaceFunction(M.getOrInsertFunction(
+ UnalignedWriteName, IRB.getVoidTy(), IRB.getInt8PtrTy(), nullptr));
+
+ Type *Ty = Type::getIntNTy(M.getContext(), BitSize);
+ Type *PtrTy = Ty->getPointerTo();
+ SmallString<32> AtomicLoadName("__tsan_atomic" + BitSizeStr + "_load");
+ TsanAtomicLoad[i] = checkSanitizerInterfaceFunction(
+ M.getOrInsertFunction(AtomicLoadName, Ty, PtrTy, OrdTy, nullptr));
+
+ SmallString<32> AtomicStoreName("__tsan_atomic" + BitSizeStr + "_store");
+ TsanAtomicStore[i] = checkSanitizerInterfaceFunction(M.getOrInsertFunction(
+ AtomicStoreName, IRB.getVoidTy(), PtrTy, Ty, OrdTy, nullptr));
+
+ 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] = checkSanitizerInterfaceFunction(
+ M.getOrInsertFunction(RMWName, Ty, PtrTy, Ty, OrdTy, nullptr));
+ }
+
+ SmallString<32> AtomicCASName("__tsan_atomic" + BitSizeStr +
+ "_compare_exchange_val");
+ TsanAtomicCAS[i] = checkSanitizerInterfaceFunction(M.getOrInsertFunction(
+ AtomicCASName, Ty, PtrTy, Ty, Ty, OrdTy, OrdTy, nullptr));
}
+ TsanVptrUpdate = checkSanitizerInterfaceFunction(
+ M.getOrInsertFunction("__tsan_vptr_update", IRB.getVoidTy(),
+ IRB.getInt8PtrTy(), IRB.getInt8PtrTy(), nullptr));
+ TsanVptrLoad = checkSanitizerInterfaceFunction(M.getOrInsertFunction(
+ "__tsan_vptr_read", IRB.getVoidTy(), IRB.getInt8PtrTy(), nullptr));
+ TsanAtomicThreadFence = checkSanitizerInterfaceFunction(M.getOrInsertFunction(
+ "__tsan_atomic_thread_fence", IRB.getVoidTy(), OrdTy, nullptr));
+ TsanAtomicSignalFence = checkSanitizerInterfaceFunction(M.getOrInsertFunction(
+ "__tsan_atomic_signal_fence", IRB.getVoidTy(), OrdTy, nullptr));
+
+ MemmoveFn = checkSanitizerInterfaceFunction(
+ M.getOrInsertFunction("memmove", IRB.getInt8PtrTy(), IRB.getInt8PtrTy(),
+ IRB.getInt8PtrTy(), IntptrTy, nullptr));
+ MemcpyFn = checkSanitizerInterfaceFunction(
+ M.getOrInsertFunction("memcpy", IRB.getInt8PtrTy(), IRB.getInt8PtrTy(),
+ IRB.getInt8PtrTy(), IntptrTy, nullptr));
+ MemsetFn = checkSanitizerInterfaceFunction(
+ M.getOrInsertFunction("memset", IRB.getInt8PtrTy(), IRB.getInt8PtrTy(),
+ IRB.getInt32Ty(), IntptrTy, nullptr));
+}
+
+bool ThreadSanitizer::doInitialization(Module &M) {
+ const DataLayout &DL = M.getDataLayout();
+ IntptrTy = DL.getIntPtrType(M.getContext());
+ std::tie(TsanCtorFunction, std::ignore) = createSanitizerCtorAndInitFunctions(
+ M, kTsanModuleCtorName, kTsanInitName, /*InitArgTypes=*/{},
+ /*InitArgs=*/{});
+
+ appendToGlobalCtors(M, TsanCtorFunction, 0);
+
return true;
}
+static bool isVtableAccess(Instruction *I) {
+ if (MDNode *Tag = I->getMetadata(LLVMContext::MD_tbaa))
+ return Tag->isTBAAVtableAccess();
+ return false;
+}
+
+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) {
+ SmallSet<Value*, 8> WriteTargets;
+ // Iterate from the end.
+ for (SmallVectorImpl<Instruction*>::reverse_iterator It = Local.rbegin(),
+ E = Local.rend(); It != E; ++It) {
+ Instruction *I = *It;
+ if (StoreInst *Store = dyn_cast<StoreInst>(I)) {
+ WriteTargets.insert(Store->getPointerOperand());
+ } else {
+ LoadInst *Load = cast<LoadInst>(I);
+ Value *Addr = Load->getPointerOperand();
+ 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) {
+ if (LoadInst *LI = dyn_cast<LoadInst>(I))
+ return LI->isAtomic() && LI->getSynchScope() == CrossThread;
+ if (StoreInst *SI = dyn_cast<StoreInst>(I))
+ return SI->isAtomic() && SI->getSynchScope() == CrossThread;
+ if (isa<AtomicRMWInst>(I))
+ return true;
+ if (isa<AtomicCmpXchgInst>(I))
+ return true;
+ if (isa<FenceInst>(I))
+ return true;
+ return false;
+}
+
bool ThreadSanitizer::runOnFunction(Function &F) {
- if (!TD) return false;
+ // 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> RetVec;
- SmallVector<Instruction*, 8> LoadsAndStores;
+ 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 (Function::iterator FI = F.begin(), FE = F.end();
- FI != FE; ++FI) {
- BasicBlock &BB = *FI;
- for (BasicBlock::iterator BI = BB.begin(), BE = BB.end();
- BI != BE; ++BI) {
- if (isa<LoadInst>(BI) || isa<StoreInst>(BI))
- LoadsAndStores.push_back(BI);
- else if (isa<ReturnInst>(BI))
- RetVec.push_back(BI);
- else if (isa<CallInst>(BI) || isa<InvokeInst>(BI))
+ 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<ReturnInst>(Inst))
+ RetVec.push_back(&Inst);
+ else if (isa<CallInst>(Inst) || isa<InvokeInst>(Inst)) {
+ 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.
- for (size_t i = 0, n = LoadsAndStores.size(); i < n; ++i) {
- Res |= instrumentLoadOrStore(LoadsAndStores[i]);
- }
+ // 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);
+ }
// Instrument function entry/exit points if there were instrumented accesses.
- if (Res || HasCalls) {
+ 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);
- for (size_t i = 0, n = RetVec.size(); i < n; ++i) {
- IRBuilder<> IRBRet(RetVec[i]);
- IRBRet.CreateCall(TsanFuncExit);
+ for (auto RetInst : RetVec) {
+ IRBuilder<> IRBRet(RetInst);
+ IRBRet.CreateCall(TsanFuncExit, {});
}
+ Res = true;
}
return Res;
}
-bool ThreadSanitizer::instrumentLoadOrStore(Instruction *I) {
+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();
+ int Idx = getMemoryAccessFuncIndex(Addr, DL);
+ if (Idx < 0)
+ return false;
+ if (IsWrite && isVtableAccess(I)) {
+ 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);
+ Value *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 NotAtomic: llvm_unreachable("unexpected atomic ordering!");
+ case Unordered: // Fall-through.
+ case Monotonic: v = 0; break;
+ // case Consume: v = 1; break; // Not specified yet.
+ case Acquire: v = 2; break;
+ case Release: v = 3; break;
+ case AcquireRelease: v = 4; break;
+ case 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())};
+ CallInst *C = CallInst::Create(TsanAtomicLoad[Idx], Args);
+ ReplaceInstWithInst(I, C);
+
+ } 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.CreateIntCast(SI->getValueOperand(), Ty, false),
+ 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;
+ Function *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 *Args[] = {IRB.CreatePointerCast(Addr, PtrTy),
+ IRB.CreateIntCast(CASI->getCompareOperand(), Ty, false),
+ IRB.CreateIntCast(CASI->getNewValOperand(), Ty, false),
+ createOrdering(&IRB, CASI->getSuccessOrdering()),
+ createOrdering(&IRB, CASI->getFailureOrdering())};
+ CallInst *C = IRB.CreateCall(TsanAtomicCAS[Idx], Args);
+ Value *Success = IRB.CreateICmpEQ(C, CASI->getCompareOperand());
+
+ Value *Res = IRB.CreateInsertValue(UndefValue::get(CASI->getType()), C, 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())};
+ Function *F = FI->getSynchScope() == 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 = TD->getTypeStoreSizeInBits(OrigTy);
+ uint32_t TypeSize = DL.getTypeStoreSizeInBits(OrigTy);
if (TypeSize != 8 && TypeSize != 16 &&
TypeSize != 32 && TypeSize != 64 && TypeSize != 128) {
+ NumAccessesWithBadSize++;
// Ignore all unusual sizes.
- return false;
+ return -1;
}
- size_t Idx = CountTrailingZeros_32(TypeSize / 8);
+ size_t Idx = countTrailingZeros(TypeSize / 8);
assert(Idx < kNumberOfAccessSizes);
- Value *OnAccessFunc = IsWrite ? TsanWrite[Idx] : TsanRead[Idx];
- IRB.CreateCall(OnAccessFunc, IRB.CreatePointerCast(Addr, IRB.getInt8PtrTy()));
- return true;
+ return Idx;
}
projects / oota-llvm.git / blobdiff