1 //===-- ThreadSanitizer.cpp - race detector -------------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file is a part of ThreadSanitizer, a race detector.
12 // The tool is under development, for the details about previous versions see
13 // http://code.google.com/p/data-race-test
15 // The instrumentation phase is quite simple:
16 // - Insert calls to run-time library before every memory access.
17 // - Optimizations may apply to avoid instrumenting some of the accesses.
18 // - Insert calls at function entry/exit.
19 // The rest is handled by the run-time library.
20 //===----------------------------------------------------------------------===//
22 #define DEBUG_TYPE "tsan"
24 #include "FunctionBlackList.h"
25 #include "llvm/ADT/SmallString.h"
26 #include "llvm/ADT/SmallVector.h"
27 #include "llvm/ADT/StringExtras.h"
28 #include "llvm/Intrinsics.h"
29 #include "llvm/Function.h"
30 #include "llvm/LLVMContext.h"
31 #include "llvm/Metadata.h"
32 #include "llvm/Module.h"
33 #include "llvm/Support/CommandLine.h"
34 #include "llvm/Support/Debug.h"
35 #include "llvm/Support/IRBuilder.h"
36 #include "llvm/Support/MathExtras.h"
37 #include "llvm/Support/raw_ostream.h"
38 #include "llvm/Target/TargetData.h"
39 #include "llvm/Transforms/Instrumentation.h"
40 #include "llvm/Transforms/Utils/ModuleUtils.h"
41 #include "llvm/Type.h"
45 static cl::opt<std::string> ClBlackListFile("tsan-blacklist",
46 cl::desc("Blacklist file"), cl::Hidden);
49 /// ThreadSanitizer: instrument the code in module to find races.
50 struct ThreadSanitizer : public FunctionPass {
52 bool runOnFunction(Function &F);
53 bool doInitialization(Module &M);
54 bool instrumentLoadOrStore(Instruction *I);
55 static char ID; // Pass identification, replacement for typeid.
59 OwningPtr<FunctionBlackList> BL;
60 // Callbacks to run-time library are computed in doInitialization.
63 // Accesses sizes are powers of two: 1, 2, 4, 8, 16.
64 static const size_t kNumberOfAccessSizes = 5;
65 Value *TsanRead[kNumberOfAccessSizes];
66 Value *TsanWrite[kNumberOfAccessSizes];
67 Value *TsanVptrUpdate;
71 char ThreadSanitizer::ID = 0;
72 INITIALIZE_PASS(ThreadSanitizer, "tsan",
73 "ThreadSanitizer: detects data races.",
76 ThreadSanitizer::ThreadSanitizer()
81 FunctionPass *llvm::createThreadSanitizerPass() {
82 return new ThreadSanitizer();
85 bool ThreadSanitizer::doInitialization(Module &M) {
86 TD = getAnalysisIfAvailable<TargetData>();
89 BL.reset(new FunctionBlackList(ClBlackListFile));
91 // Always insert a call to __tsan_init into the module's CTORs.
92 IRBuilder<> IRB(M.getContext());
93 Value *TsanInit = M.getOrInsertFunction("__tsan_init",
94 IRB.getVoidTy(), NULL);
95 appendToGlobalCtors(M, cast<Function>(TsanInit), 0);
97 // Initialize the callbacks.
98 TsanFuncEntry = M.getOrInsertFunction("__tsan_func_entry", IRB.getVoidTy(),
99 IRB.getInt8PtrTy(), NULL);
100 TsanFuncExit = M.getOrInsertFunction("__tsan_func_exit", IRB.getVoidTy(),
102 for (size_t i = 0; i < kNumberOfAccessSizes; ++i) {
103 SmallString<32> ReadName("__tsan_read");
104 ReadName += itostr(1 << i);
105 TsanRead[i] = M.getOrInsertFunction(ReadName, IRB.getVoidTy(),
106 IRB.getInt8PtrTy(), NULL);
107 SmallString<32> WriteName("__tsan_write");
108 WriteName += itostr(1 << i);
109 TsanWrite[i] = M.getOrInsertFunction(WriteName, IRB.getVoidTy(),
110 IRB.getInt8PtrTy(), NULL);
112 TsanVptrUpdate = M.getOrInsertFunction("__tsan_vptr_update", IRB.getVoidTy(),
113 IRB.getInt8PtrTy(), IRB.getInt8PtrTy(),
118 bool ThreadSanitizer::runOnFunction(Function &F) {
119 if (!TD) return false;
120 if (BL->isIn(F)) return false;
121 SmallVector<Instruction*, 8> RetVec;
122 SmallVector<Instruction*, 8> LoadsAndStores;
124 bool HasCalls = false;
126 // Traverse all instructions, collect loads/stores/returns, check for calls.
127 for (Function::iterator FI = F.begin(), FE = F.end();
129 BasicBlock &BB = *FI;
130 for (BasicBlock::iterator BI = BB.begin(), BE = BB.end();
132 if (isa<LoadInst>(BI) || isa<StoreInst>(BI))
133 LoadsAndStores.push_back(BI);
134 else if (isa<ReturnInst>(BI))
135 RetVec.push_back(BI);
136 else if (isa<CallInst>(BI) || isa<InvokeInst>(BI))
141 // We have collected all loads and stores.
142 // FIXME: many of these accesses do not need to be checked for races
143 // (e.g. variables that do not escape, etc).
145 // Instrument memory accesses.
146 for (size_t i = 0, n = LoadsAndStores.size(); i < n; ++i) {
147 Res |= instrumentLoadOrStore(LoadsAndStores[i]);
150 // Instrument function entry/exit points if there were instrumented accesses.
151 if (Res || HasCalls) {
152 IRBuilder<> IRB(F.getEntryBlock().getFirstNonPHI());
153 Value *ReturnAddress = IRB.CreateCall(
154 Intrinsic::getDeclaration(F.getParent(), Intrinsic::returnaddress),
156 IRB.CreateCall(TsanFuncEntry, ReturnAddress);
157 for (size_t i = 0, n = RetVec.size(); i < n; ++i) {
158 IRBuilder<> IRBRet(RetVec[i]);
159 IRBRet.CreateCall(TsanFuncExit);
166 static bool isVtableAccess(Instruction *I) {
167 if (MDNode *Tag = I->getMetadata(LLVMContext::MD_tbaa)) {
168 if (Tag->getNumOperands() < 1) return false;
169 if (MDString *Tag1 = dyn_cast<MDString>(Tag->getOperand(0))) {
170 if (Tag1->getString() == "vtable pointer") return true;
176 bool ThreadSanitizer::instrumentLoadOrStore(Instruction *I) {
178 bool IsWrite = isa<StoreInst>(*I);
179 Value *Addr = IsWrite
180 ? cast<StoreInst>(I)->getPointerOperand()
181 : cast<LoadInst>(I)->getPointerOperand();
182 Type *OrigPtrTy = Addr->getType();
183 Type *OrigTy = cast<PointerType>(OrigPtrTy)->getElementType();
184 assert(OrigTy->isSized());
185 uint32_t TypeSize = TD->getTypeStoreSizeInBits(OrigTy);
186 if (TypeSize != 8 && TypeSize != 16 &&
187 TypeSize != 32 && TypeSize != 64 && TypeSize != 128) {
188 // Ignore all unusual sizes.
191 if (IsWrite && isVtableAccess(I)) {
192 Value *StoredValue = cast<StoreInst>(I)->getValueOperand();
193 IRB.CreateCall2(TsanVptrUpdate,
194 IRB.CreatePointerCast(Addr, IRB.getInt8PtrTy()),
195 IRB.CreatePointerCast(StoredValue, IRB.getInt8PtrTy()));
198 size_t Idx = CountTrailingZeros_32(TypeSize / 8);
199 assert(Idx < kNumberOfAccessSizes);
200 Value *OnAccessFunc = IsWrite ? TsanWrite[Idx] : TsanRead[Idx];
201 IRB.CreateCall(OnAccessFunc, IRB.CreatePointerCast(Addr, IRB.getInt8PtrTy()));