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llvm-6502/lib/Transforms/Instrumentation/ThreadSanitizer.cpp
Dmitry Vyukov c2e9ca15fb tsan: switch to new memory_order constants (ABI compatible) 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167615 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-09 14:12:16 +00:00

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//===-- ThreadSanitizer.cpp - race detector -------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// 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.
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "tsan"
#include "BlackList.h"
#include "llvm/Function.h"
#include "llvm/IRBuilder.h"
#include "llvm/Intrinsics.h"
#include "llvm/LLVMContext.h"
#include "llvm/Metadata.h"
#include "llvm/Module.h"
#include "llvm/Type.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/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/DataLayout.h"
#include "llvm/Transforms/Instrumentation.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/ModuleUtils.h"
using namespace llvm;
static cl::opt<std::string> ClBlackListFile("tsan-blacklist",
cl::desc("Blacklist file"), cl::Hidden);
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);
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(NumOmittedReadsFromConstantGlobals,
"Number of reads from constant globals");
STATISTIC(NumOmittedReadsFromVtable, "Number of vtable reads");
namespace {
/// ThreadSanitizer: instrument the code in module to find races.
struct ThreadSanitizer : public FunctionPass {
ThreadSanitizer();
const char *getPassName() const;
bool runOnFunction(Function &F);
bool doInitialization(Module &M);
static char ID; // Pass identification, replacement for typeid.
private:
bool instrumentLoadOrStore(Instruction *I);
bool instrumentAtomic(Instruction *I);
void chooseInstructionsToInstrument(SmallVectorImpl<Instruction*> &Local,
SmallVectorImpl<Instruction*> &All);
bool addrPointsToConstantData(Value *Addr);
int getMemoryAccessFuncIndex(Value *Addr);
DataLayout *TD;
OwningPtr<BlackList> BL;
IntegerType *OrdTy;
// Callbacks to run-time library are computed in doInitialization.
Function *TsanFuncEntry;
Function *TsanFuncExit;
// Accesses sizes are powers of two: 1, 2, 4, 8, 16.
static const size_t kNumberOfAccessSizes = 5;
Function *TsanRead[kNumberOfAccessSizes];
Function *TsanWrite[kNumberOfAccessSizes];
Function *TsanAtomicLoad[kNumberOfAccessSizes];
Function *TsanAtomicStore[kNumberOfAccessSizes];
Function *TsanAtomicRMW[AtomicRMWInst::LAST_BINOP + 1][kNumberOfAccessSizes];
Function *TsanAtomicCAS[kNumberOfAccessSizes];
Function *TsanAtomicThreadFence;
Function *TsanAtomicSignalFence;
Function *TsanVptrUpdate;
};
} // namespace
char ThreadSanitizer::ID = 0;
INITIALIZE_PASS(ThreadSanitizer, "tsan",
"ThreadSanitizer: detects data races.",
false, false)
const char *ThreadSanitizer::getPassName() const {
return "ThreadSanitizer";
}
ThreadSanitizer::ThreadSanitizer()
: FunctionPass(ID),
TD(NULL) {
}
FunctionPass *llvm::createThreadSanitizerPass() {
return new ThreadSanitizer();
}
static Function *checkInterfaceFunction(Constant *FuncOrBitcast) {
if (Function *F = dyn_cast<Function>(FuncOrBitcast))
return F;
FuncOrBitcast->dump();
report_fatal_error("ThreadSanitizer interface function redefined");
}
bool ThreadSanitizer::doInitialization(Module &M) {
TD = getAnalysisIfAvailable<DataLayout>();
if (!TD)
return false;
BL.reset(new BlackList(ClBlackListFile));
// Always insert a call to __tsan_init into the module's CTORs.
IRBuilder<> IRB(M.getContext());
Value *TsanInit = M.getOrInsertFunction("__tsan_init",
IRB.getVoidTy(), NULL);
appendToGlobalCtors(M, cast<Function>(TsanInit), 0);
// Initialize the callbacks.
TsanFuncEntry = checkInterfaceFunction(M.getOrInsertFunction(
"__tsan_func_entry", IRB.getVoidTy(), IRB.getInt8PtrTy(), NULL));
TsanFuncExit = checkInterfaceFunction(M.getOrInsertFunction(
"__tsan_func_exit", IRB.getVoidTy(), NULL));
OrdTy = IRB.getInt32Ty();
for (size_t i = 0; i < kNumberOfAccessSizes; ++i) {
const size_t ByteSize = 1 << i;
const size_t BitSize = ByteSize * 8;
SmallString<32> ReadName("__tsan_read" + itostr(ByteSize));
TsanRead[i] = checkInterfaceFunction(M.getOrInsertFunction(
ReadName, IRB.getVoidTy(), IRB.getInt8PtrTy(), NULL));
SmallString<32> WriteName("__tsan_write" + itostr(ByteSize));
TsanWrite[i] = checkInterfaceFunction(M.getOrInsertFunction(
WriteName, IRB.getVoidTy(), IRB.getInt8PtrTy(), NULL));
Type *Ty = Type::getIntNTy(M.getContext(), BitSize);
Type *PtrTy = Ty->getPointerTo();
SmallString<32> AtomicLoadName("__tsan_atomic" + itostr(BitSize) +
"_load");
TsanAtomicLoad[i] = checkInterfaceFunction(M.getOrInsertFunction(
AtomicLoadName, Ty, PtrTy, OrdTy, NULL));
SmallString<32> AtomicStoreName("__tsan_atomic" + itostr(BitSize) +
"_store");
TsanAtomicStore[i] = checkInterfaceFunction(M.getOrInsertFunction(
AtomicStoreName, IRB.getVoidTy(), PtrTy, Ty, OrdTy,
NULL));
for (int op = AtomicRMWInst::FIRST_BINOP;
op <= AtomicRMWInst::LAST_BINOP; ++op) {
TsanAtomicRMW[op][i] = NULL;
const char *NamePart = NULL;
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
continue;
SmallString<32> RMWName("__tsan_atomic" + itostr(BitSize) + NamePart);
TsanAtomicRMW[op][i] = checkInterfaceFunction(M.getOrInsertFunction(
RMWName, Ty, PtrTy, Ty, OrdTy, NULL));
}
SmallString<32> AtomicCASName("__tsan_atomic" + itostr(BitSize) +
"_compare_exchange_val");
TsanAtomicCAS[i] = checkInterfaceFunction(M.getOrInsertFunction(
AtomicCASName, Ty, PtrTy, Ty, Ty, OrdTy, NULL));
}
TsanVptrUpdate = checkInterfaceFunction(M.getOrInsertFunction(
"__tsan_vptr_update", IRB.getVoidTy(), IRB.getInt8PtrTy(),
IRB.getInt8PtrTy(), NULL));
TsanAtomicThreadFence = checkInterfaceFunction(M.getOrInsertFunction(
"__tsan_atomic_thread_fence", IRB.getVoidTy(), OrdTy, NULL));
TsanAtomicSignalFence = checkInterfaceFunction(M.getOrInsertFunction(
"__tsan_atomic_signal_fence", IRB.getVoidTy(), OrdTy, NULL));
return true;
}
static bool isVtableAccess(Instruction *I) {
if (MDNode *Tag = I->getMetadata(LLVMContext::MD_tbaa)) {
if (Tag->getNumOperands() < 1) return false;
if (MDString *Tag1 = dyn_cast<MDString>(Tag->getOperand(0))) {
if (Tag1->getString() == "vtable pointer") return true;
}
}
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)
//
// 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) {
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;
}
}
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;
if (BL->isIn(F)) return false;
SmallVector<Instruction*, 8> RetVec;
SmallVector<Instruction*, 8> AllLoadsAndStores;
SmallVector<Instruction*, 8> LocalLoadsAndStores;
SmallVector<Instruction*, 8> AtomicAccesses;
bool Res = false;
bool HasCalls = false;
// 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 (isAtomic(BI))
AtomicAccesses.push_back(BI);
else if (isa<LoadInst>(BI) || isa<StoreInst>(BI))
LocalLoadsAndStores.push_back(BI);
else if (isa<ReturnInst>(BI))
RetVec.push_back(BI);
else if (isa<CallInst>(BI) || isa<InvokeInst>(BI)) {
HasCalls = true;
chooseInstructionsToInstrument(LocalLoadsAndStores, AllLoadsAndStores);
}
}
chooseInstructionsToInstrument(LocalLoadsAndStores, AllLoadsAndStores);
}
// 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.
if (ClInstrumentMemoryAccesses)
for (size_t i = 0, n = AllLoadsAndStores.size(); i < n; ++i) {
Res |= instrumentLoadOrStore(AllLoadsAndStores[i]);
}
// Instrument atomic memory accesses.
if (ClInstrumentAtomics)
for (size_t i = 0, n = AtomicAccesses.size(); i < n; ++i) {
Res |= instrumentAtomic(AtomicAccesses[i]);
}
// 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);
for (size_t i = 0, n = RetVec.size(); i < n; ++i) {
IRBuilder<> IRBRet(RetVec[i]);
IRBRet.CreateCall(TsanFuncExit);
}
Res = true;
}
return Res;
}
bool ThreadSanitizer::instrumentLoadOrStore(Instruction *I) {
IRBuilder<> IRB(I);
bool IsWrite = isa<StoreInst>(*I);
Value *Addr = IsWrite
? cast<StoreInst>(I)->getPointerOperand()
: cast<LoadInst>(I)->getPointerOperand();
int Idx = getMemoryAccessFuncIndex(Addr);
if (Idx < 0)
return false;
if (IsWrite && isVtableAccess(I)) {
DEBUG(dbgs() << " VPTR : " << *I << "\n");
Value *StoredValue = cast<StoreInst>(I)->getValueOperand();
// StoredValue does not necessary have a pointer type.
if (isa<IntegerType>(StoredValue->getType()))
StoredValue = IRB.CreateIntToPtr(StoredValue, IRB.getInt8PtrTy());
// Call TsanVptrUpdate.
IRB.CreateCall2(TsanVptrUpdate,
IRB.CreatePointerCast(Addr, IRB.getInt8PtrTy()),
IRB.CreatePointerCast(StoredValue, IRB.getInt8PtrTy()));
NumInstrumentedVtableWrites++;
return true;
}
Value *OnAccessFunc = IsWrite ? TsanWrite[Idx] : TsanRead[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: assert(false);
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);
}
bool ThreadSanitizer::instrumentAtomic(Instruction *I) {
IRBuilder<> IRB(I);
if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
Value *Addr = LI->getPointerOperand();
int Idx = getMemoryAccessFuncIndex(Addr);
if (Idx < 0)
return false;
const size_t ByteSize = 1 << Idx;
const size_t 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],
ArrayRef<Value*>(Args));
ReplaceInstWithInst(I, C);
} else if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
Value *Addr = SI->getPointerOperand();
int Idx = getMemoryAccessFuncIndex(Addr);
if (Idx < 0)
return false;
const size_t ByteSize = 1 << Idx;
const size_t 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],
ArrayRef<Value*>(Args));
ReplaceInstWithInst(I, C);
} else if (AtomicRMWInst *RMWI = dyn_cast<AtomicRMWInst>(I)) {
Value *Addr = RMWI->getPointerOperand();
int Idx = getMemoryAccessFuncIndex(Addr);
if (Idx < 0)
return false;
Function *F = TsanAtomicRMW[RMWI->getOperation()][Idx];
if (F == NULL)
return false;
const size_t ByteSize = 1 << Idx;
const size_t 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, ArrayRef<Value*>(Args));
ReplaceInstWithInst(I, C);
} else if (AtomicCmpXchgInst *CASI = dyn_cast<AtomicCmpXchgInst>(I)) {
Value *Addr = CASI->getPointerOperand();
int Idx = getMemoryAccessFuncIndex(Addr);
if (Idx < 0)
return false;
const size_t ByteSize = 1 << Idx;
const size_t 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->getOrdering())};
CallInst *C = CallInst::Create(TsanAtomicCAS[Idx], ArrayRef<Value*>(Args));
ReplaceInstWithInst(I, C);
} 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, ArrayRef<Value*>(Args));
ReplaceInstWithInst(I, C);
}
return true;
}
int ThreadSanitizer::getMemoryAccessFuncIndex(Value *Addr) {
Type *OrigPtrTy = Addr->getType();
Type *OrigTy = cast<PointerType>(OrigPtrTy)->getElementType();
assert(OrigTy->isSized());
uint32_t TypeSize = TD->getTypeStoreSizeInBits(OrigTy);
if (TypeSize != 8 && TypeSize != 16 &&
TypeSize != 32 && TypeSize != 64 && TypeSize != 128) {
NumAccessesWithBadSize++;
// Ignore all unusual sizes.
return -1;
}
size_t Idx = CountTrailingZeros_32(TypeSize / 8);
assert(Idx < kNumberOfAccessSizes);
return Idx;
}
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