ThreadSanitizer, a race detector. First LLVM commit.
Clang patch (flags) will follow shortly.
The run-time library will also follow, but not immediately.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150423 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Instrumentation/ThreadSanitizer.cpp b/lib/Transforms/Instrumentation/ThreadSanitizer.cpp
new file mode 100644
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--- /dev/null
+++ 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 "llvm/ADT/SmallString.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/Intrinsics.h"
+#include "llvm/Function.h"
+#include "llvm/Module.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/Transforms/Utils/ModuleUtils.h"
+#include "llvm/Type.h"
+
+using namespace llvm;
+
+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);
+ static char ID; // Pass identification, replacement for typeid.
+
+ private:
+ TargetData *TD;
+ // 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 int kNumberOfAccessSizes = 5;
+ Value *TsanRead[kNumberOfAccessSizes];
+ Value *TsanWrite[kNumberOfAccessSizes];
+};
+} // 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;
+ // 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 (int 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);
+ }
+ return true;
+}
+
+bool ThreadSanitizer::runOnFunction(Function &F) {
+ if (!TD) return false;
+ SmallVector<Instruction*, 8> RetVec;
+ SmallVector<Instruction*, 8> LoadsAndStores;
+ 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))
+ LoadsAndStores.push_back(BI);
+ else if (isa<ReturnInst>(BI))
+ RetVec.push_back(BI);
+ else if (isa<CallInst>(BI) || isa<InvokeInst>(BI))
+ HasCalls = true;
+ }
+ }
+
+ // 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 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);
+ }
+ }
+ 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) {
+ // Ignore all unusual sizes.
+ return false;
+ }
+ uint32_t Idx = CountTrailingZeros_32(TypeSize / 8);
+ assert(Idx < kNumberOfAccessSizes);
+ Value *OnAccessFunc = IsWrite ? TsanWrite[Idx] : TsanRead[Idx];
+ IRB.CreateCall(OnAccessFunc, IRB.CreatePointerCast(Addr, IRB.getInt8PtrTy()));
+ return true;
+}