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diff --git a/lib/Transforms/Instrumentation/ThreadSanitizer.cpp b/lib/Transforms/Instrumentation/ThreadSanitizer.cpp
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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 "FunctionBlackList.h"
+#include "llvm/ADT/SmallSet.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/Intrinsics.h"
+#include "llvm/Function.h"
+#include "llvm/LLVMContext.h"
+#include "llvm/Metadata.h"
+#include "llvm/Module.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/IRBuilder.h"
+#include "llvm/Support/MathExtras.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/Transforms/Instrumentation.h"
+#include "llvm/Transforms/Utils/ModuleUtils.h"
+#include "llvm/Type.h"
+
+using namespace llvm;
+
+static cl::opt<std::string>  ClBlackListFile("tsan-blacklist",
+       cl::desc("Blacklist file"), cl::Hidden);
+
+static cl::opt<bool> ClPrintStats("tsan-print-stats",
+       cl::desc("Print ThreadSanitizer instrumentation stats"), cl::Hidden);
+
+namespace {
+
+// Stats counters for ThreadSanitizer instrumentation.
+struct ThreadSanitizerStats {
+  size_t NumInstrumentedReads;
+  size_t NumInstrumentedWrites;
+  size_t NumOmittedReadsBeforeWrite;
+  size_t NumAccessesWithBadSize;
+  size_t NumInstrumentedVtableWrites;
+  size_t NumOmittedReadsFromConstantGlobals;
+  size_t NumOmittedReadsFromVtable;
+};
+
+/// ThreadSanitizer: instrument the code in module to find races.
+struct ThreadSanitizer : public FunctionPass {
+  ThreadSanitizer();
+  bool runOnFunction(Function &F);
+  bool doInitialization(Module &M);
+  bool doFinalization(Module &M);
+  bool instrumentLoadOrStore(Instruction *I);
+  static char ID;  // Pass identification, replacement for typeid.
+
+ private:
+  void choseInstructionsToInstrument(SmallVectorImpl<Instruction*> &Local,
+                                     SmallVectorImpl<Instruction*> &All);
+  bool addrPointsToConstantData(Value *Addr);
+
+  TargetData *TD;
+  OwningPtr<FunctionBlackList> BL;
+  // Callbacks to run-time library are computed in doInitialization.
+  Value *TsanFuncEntry;
+  Value *TsanFuncExit;
+  // Accesses sizes are powers of two: 1, 2, 4, 8, 16.
+  static const size_t kNumberOfAccessSizes = 5;
+  Value *TsanRead[kNumberOfAccessSizes];
+  Value *TsanWrite[kNumberOfAccessSizes];
+  Value *TsanVptrUpdate;
+
+  // Stats are modified w/o synchronization.
+  ThreadSanitizerStats stats;
+};
+}  // namespace
+
+char ThreadSanitizer::ID = 0;
+INITIALIZE_PASS(ThreadSanitizer, "tsan",
+    "ThreadSanitizer: detects data races.",
+    false, false)
+
+ThreadSanitizer::ThreadSanitizer()
+  : FunctionPass(ID),
+  TD(NULL) {
+}
+
+FunctionPass *llvm::createThreadSanitizerPass() {
+  return new ThreadSanitizer();
+}
+
+bool ThreadSanitizer::doInitialization(Module &M) {
+  TD = getAnalysisIfAvailable<TargetData>();
+  if (!TD)
+    return false;
+  BL.reset(new FunctionBlackList(ClBlackListFile));
+  memset(&stats, 0, sizeof(stats));
+
+  // 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 = M.getOrInsertFunction("__tsan_func_entry", IRB.getVoidTy(),
+                                        IRB.getInt8PtrTy(), NULL);
+  TsanFuncExit = M.getOrInsertFunction("__tsan_func_exit", IRB.getVoidTy(),
+                                       NULL);
+  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);
+  }
+  TsanVptrUpdate = M.getOrInsertFunction("__tsan_vptr_update", IRB.getVoidTy(),
+                                         IRB.getInt8PtrTy(), IRB.getInt8PtrTy(),
+                                         NULL);
+  return true;
+}
+
+bool ThreadSanitizer::doFinalization(Module &M) {
+  if (ClPrintStats) {
+    errs() << "ThreadSanitizerStats " << M.getModuleIdentifier()
+           << ": wr " << stats.NumInstrumentedWrites
+           << "; rd " << stats.NumInstrumentedReads
+           << "; vt " << stats.NumInstrumentedVtableWrites
+           << "; bs " << stats.NumAccessesWithBadSize
+           << "; rbw " << stats.NumOmittedReadsBeforeWrite
+           << "; rcg " << stats.NumOmittedReadsFromConstantGlobals
+           << "; rvt " << stats.NumOmittedReadsFromVtable
+           << "\n";
+  }
+  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.
+      stats.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.
+      stats.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::choseInstructionsToInstrument(
+    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.
+        stats.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();
+}
+
+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;
+  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 (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;
+        choseInstructionsToInstrument(LocalLoadsAndStores, AllLoadsAndStores);
+      }
+    }
+    choseInstructionsToInstrument(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.
+  for (size_t i = 0, n = AllLoadsAndStores.size(); i < n; ++i) {
+    Res |= instrumentLoadOrStore(AllLoadsAndStores[i]);
+  }
+
+  // Instrument function entry/exit points if there were instrumented accesses.
+  if (Res || HasCalls) {
+    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();
+  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) {
+    stats.NumAccessesWithBadSize++;
+    // Ignore all unusual sizes.
+    return false;
+  }
+  if (IsWrite && isVtableAccess(I)) {
+    Value *StoredValue = cast<StoreInst>(I)->getValueOperand();
+    IRB.CreateCall2(TsanVptrUpdate,
+                    IRB.CreatePointerCast(Addr, IRB.getInt8PtrTy()),
+                    IRB.CreatePointerCast(StoredValue, IRB.getInt8PtrTy()));
+    stats.NumInstrumentedVtableWrites++;
+    return true;
+  }
+  size_t Idx = CountTrailingZeros_32(TypeSize / 8);
+  assert(Idx < kNumberOfAccessSizes);
+  Value *OnAccessFunc = IsWrite ? TsanWrite[Idx] : TsanRead[Idx];
+  IRB.CreateCall(OnAccessFunc, IRB.CreatePointerCast(Addr, IRB.getInt8PtrTy()));
+  if (IsWrite) stats.NumInstrumentedWrites++;
+  else         stats.NumInstrumentedReads++;
+  return true;
+}