mirror of
https://github.com/c64scene-ar/llvm-6502.git
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@155986 91177308-0d34-0410-b5e6-96231b3b80d8
408 lines
14 KiB
C++
408 lines
14 KiB
C++
//===-- ThreadSanitizer.cpp - race detector -------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file is a part of ThreadSanitizer, a race detector.
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//
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// The tool is under development, for the details about previous versions see
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// http://code.google.com/p/data-race-test
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//
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// The instrumentation phase is quite simple:
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// - Insert calls to run-time library before every memory access.
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// - Optimizations may apply to avoid instrumenting some of the accesses.
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// - Insert calls at function entry/exit.
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// The rest is handled by the run-time library.
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//===----------------------------------------------------------------------===//
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#define DEBUG_TYPE "tsan"
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#include "FunctionBlackList.h"
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#include "llvm/ADT/SmallSet.h"
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#include "llvm/ADT/SmallString.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/ADT/Statistic.h"
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#include "llvm/ADT/StringExtras.h"
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#include "llvm/Intrinsics.h"
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#include "llvm/Function.h"
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#include "llvm/LLVMContext.h"
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#include "llvm/Metadata.h"
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#include "llvm/Module.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/IRBuilder.h"
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#include "llvm/Support/MathExtras.h"
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#include "llvm/Support/raw_ostream.h"
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#include "llvm/Target/TargetData.h"
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#include "llvm/Transforms/Instrumentation.h"
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#include "llvm/Transforms/Utils/BasicBlockUtils.h"
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#include "llvm/Transforms/Utils/ModuleUtils.h"
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#include "llvm/Type.h"
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using namespace llvm;
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static cl::opt<std::string> ClBlackListFile("tsan-blacklist",
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cl::desc("Blacklist file"), cl::Hidden);
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STATISTIC(NumInstrumentedReads, "Number of instrumented reads");
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STATISTIC(NumInstrumentedWrites, "Number of instrumented writes");
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STATISTIC(NumOmittedReadsBeforeWrite,
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"Number of reads ignored due to following writes");
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STATISTIC(NumAccessesWithBadSize, "Number of accesses with bad size");
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STATISTIC(NumInstrumentedVtableWrites, "Number of vtable ptr writes");
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STATISTIC(NumOmittedReadsFromConstantGlobals,
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"Number of reads from constant globals");
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STATISTIC(NumOmittedReadsFromVtable, "Number of vtable reads");
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namespace {
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/// ThreadSanitizer: instrument the code in module to find races.
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struct ThreadSanitizer : public FunctionPass {
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ThreadSanitizer();
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const char *getPassName() const;
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bool runOnFunction(Function &F);
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bool doInitialization(Module &M);
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static char ID; // Pass identification, replacement for typeid.
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private:
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bool instrumentLoadOrStore(Instruction *I);
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bool instrumentAtomic(Instruction *I);
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void chooseInstructionsToInstrument(SmallVectorImpl<Instruction*> &Local,
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SmallVectorImpl<Instruction*> &All);
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bool addrPointsToConstantData(Value *Addr);
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int getMemoryAccessFuncIndex(Value *Addr);
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TargetData *TD;
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OwningPtr<FunctionBlackList> BL;
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IntegerType *OrdTy;
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// Callbacks to run-time library are computed in doInitialization.
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Function *TsanFuncEntry;
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Function *TsanFuncExit;
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// Accesses sizes are powers of two: 1, 2, 4, 8, 16.
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static const size_t kNumberOfAccessSizes = 5;
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Function *TsanRead[kNumberOfAccessSizes];
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Function *TsanWrite[kNumberOfAccessSizes];
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Function *TsanAtomicLoad[kNumberOfAccessSizes];
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Function *TsanAtomicStore[kNumberOfAccessSizes];
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Function *TsanVptrUpdate;
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};
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} // namespace
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char ThreadSanitizer::ID = 0;
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INITIALIZE_PASS(ThreadSanitizer, "tsan",
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"ThreadSanitizer: detects data races.",
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false, false)
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const char *ThreadSanitizer::getPassName() const {
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return "ThreadSanitizer";
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}
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ThreadSanitizer::ThreadSanitizer()
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: FunctionPass(ID),
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TD(NULL) {
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}
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FunctionPass *llvm::createThreadSanitizerPass() {
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return new ThreadSanitizer();
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}
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static Function *checkInterfaceFunction(Constant *FuncOrBitcast) {
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if (Function *F = dyn_cast<Function>(FuncOrBitcast))
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return F;
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FuncOrBitcast->dump();
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report_fatal_error("ThreadSanitizer interface function redefined");
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}
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bool ThreadSanitizer::doInitialization(Module &M) {
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TD = getAnalysisIfAvailable<TargetData>();
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if (!TD)
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return false;
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BL.reset(new FunctionBlackList(ClBlackListFile));
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// Always insert a call to __tsan_init into the module's CTORs.
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IRBuilder<> IRB(M.getContext());
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Value *TsanInit = M.getOrInsertFunction("__tsan_init",
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IRB.getVoidTy(), NULL);
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appendToGlobalCtors(M, cast<Function>(TsanInit), 0);
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// Initialize the callbacks.
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TsanFuncEntry = checkInterfaceFunction(M.getOrInsertFunction(
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"__tsan_func_entry", IRB.getVoidTy(), IRB.getInt8PtrTy(), NULL));
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TsanFuncExit = checkInterfaceFunction(M.getOrInsertFunction(
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"__tsan_func_exit", IRB.getVoidTy(), NULL));
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OrdTy = IRB.getInt32Ty();
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for (size_t i = 0; i < kNumberOfAccessSizes; ++i) {
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const size_t ByteSize = 1 << i;
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const size_t BitSize = ByteSize * 8;
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SmallString<32> ReadName("__tsan_read" + itostr(ByteSize));
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TsanRead[i] = checkInterfaceFunction(M.getOrInsertFunction(
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ReadName, IRB.getVoidTy(), IRB.getInt8PtrTy(), NULL));
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SmallString<32> WriteName("__tsan_write" + itostr(ByteSize));
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TsanWrite[i] = checkInterfaceFunction(M.getOrInsertFunction(
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WriteName, IRB.getVoidTy(), IRB.getInt8PtrTy(), NULL));
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Type *Ty = Type::getIntNTy(M.getContext(), BitSize);
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Type *PtrTy = Ty->getPointerTo();
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SmallString<32> AtomicLoadName("__tsan_atomic" + itostr(BitSize) +
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"_load");
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TsanAtomicLoad[i] = checkInterfaceFunction(M.getOrInsertFunction(
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AtomicLoadName, Ty, PtrTy, OrdTy, NULL));
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SmallString<32> AtomicStoreName("__tsan_atomic" + itostr(BitSize) +
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"_store");
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TsanAtomicStore[i] = checkInterfaceFunction(M.getOrInsertFunction(
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AtomicStoreName, IRB.getVoidTy(), PtrTy, Ty, OrdTy,
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NULL));
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}
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TsanVptrUpdate = checkInterfaceFunction(M.getOrInsertFunction(
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"__tsan_vptr_update", IRB.getVoidTy(), IRB.getInt8PtrTy(),
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IRB.getInt8PtrTy(), NULL));
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return true;
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}
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static bool isVtableAccess(Instruction *I) {
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if (MDNode *Tag = I->getMetadata(LLVMContext::MD_tbaa)) {
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if (Tag->getNumOperands() < 1) return false;
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if (MDString *Tag1 = dyn_cast<MDString>(Tag->getOperand(0))) {
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if (Tag1->getString() == "vtable pointer") return true;
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}
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}
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return false;
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}
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bool ThreadSanitizer::addrPointsToConstantData(Value *Addr) {
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// If this is a GEP, just analyze its pointer operand.
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if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Addr))
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Addr = GEP->getPointerOperand();
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if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Addr)) {
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if (GV->isConstant()) {
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// Reads from constant globals can not race with any writes.
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NumOmittedReadsFromConstantGlobals++;
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return true;
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}
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} else if(LoadInst *L = dyn_cast<LoadInst>(Addr)) {
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if (isVtableAccess(L)) {
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// Reads from a vtable pointer can not race with any writes.
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NumOmittedReadsFromVtable++;
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return true;
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}
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}
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return false;
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}
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// Instrumenting some of the accesses may be proven redundant.
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// Currently handled:
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// - read-before-write (within same BB, no calls between)
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//
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// We do not handle some of the patterns that should not survive
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// after the classic compiler optimizations.
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// E.g. two reads from the same temp should be eliminated by CSE,
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// two writes should be eliminated by DSE, etc.
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//
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// 'Local' is a vector of insns within the same BB (no calls between).
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// 'All' is a vector of insns that will be instrumented.
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void ThreadSanitizer::chooseInstructionsToInstrument(
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SmallVectorImpl<Instruction*> &Local,
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SmallVectorImpl<Instruction*> &All) {
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SmallSet<Value*, 8> WriteTargets;
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// Iterate from the end.
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for (SmallVectorImpl<Instruction*>::reverse_iterator It = Local.rbegin(),
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E = Local.rend(); It != E; ++It) {
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Instruction *I = *It;
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if (StoreInst *Store = dyn_cast<StoreInst>(I)) {
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WriteTargets.insert(Store->getPointerOperand());
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} else {
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LoadInst *Load = cast<LoadInst>(I);
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Value *Addr = Load->getPointerOperand();
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if (WriteTargets.count(Addr)) {
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// We will write to this temp, so no reason to analyze the read.
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NumOmittedReadsBeforeWrite++;
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continue;
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}
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if (addrPointsToConstantData(Addr)) {
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// Addr points to some constant data -- it can not race with any writes.
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continue;
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}
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}
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All.push_back(I);
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}
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Local.clear();
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}
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static bool isAtomic(Instruction *I) {
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if (LoadInst *LI = dyn_cast<LoadInst>(I))
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return LI->isAtomic() && LI->getSynchScope() == CrossThread;
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if (StoreInst *SI = dyn_cast<StoreInst>(I))
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return SI->isAtomic() && SI->getSynchScope() == CrossThread;
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if (isa<AtomicRMWInst>(I))
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return true;
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if (isa<AtomicCmpXchgInst>(I))
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return true;
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if (FenceInst *FI = dyn_cast<FenceInst>(I))
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return FI->getSynchScope() == CrossThread;
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return false;
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}
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bool ThreadSanitizer::runOnFunction(Function &F) {
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if (!TD) return false;
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if (BL->isIn(F)) return false;
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SmallVector<Instruction*, 8> RetVec;
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SmallVector<Instruction*, 8> AllLoadsAndStores;
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SmallVector<Instruction*, 8> LocalLoadsAndStores;
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SmallVector<Instruction*, 8> AtomicAccesses;
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bool Res = false;
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bool HasCalls = false;
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// Traverse all instructions, collect loads/stores/returns, check for calls.
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for (Function::iterator FI = F.begin(), FE = F.end();
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FI != FE; ++FI) {
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BasicBlock &BB = *FI;
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for (BasicBlock::iterator BI = BB.begin(), BE = BB.end();
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BI != BE; ++BI) {
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if (isAtomic(BI))
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AtomicAccesses.push_back(BI);
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else if (isa<LoadInst>(BI) || isa<StoreInst>(BI))
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LocalLoadsAndStores.push_back(BI);
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else if (isa<ReturnInst>(BI))
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RetVec.push_back(BI);
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else if (isa<CallInst>(BI) || isa<InvokeInst>(BI)) {
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HasCalls = true;
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chooseInstructionsToInstrument(LocalLoadsAndStores, AllLoadsAndStores);
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}
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}
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chooseInstructionsToInstrument(LocalLoadsAndStores, AllLoadsAndStores);
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}
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// We have collected all loads and stores.
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// FIXME: many of these accesses do not need to be checked for races
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// (e.g. variables that do not escape, etc).
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// Instrument memory accesses.
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for (size_t i = 0, n = AllLoadsAndStores.size(); i < n; ++i) {
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Res |= instrumentLoadOrStore(AllLoadsAndStores[i]);
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}
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// Instrument atomic memory accesses.
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for (size_t i = 0, n = AtomicAccesses.size(); i < n; ++i) {
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Res |= instrumentAtomic(AtomicAccesses[i]);
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}
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// Instrument function entry/exit points if there were instrumented accesses.
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if (Res || HasCalls) {
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IRBuilder<> IRB(F.getEntryBlock().getFirstNonPHI());
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Value *ReturnAddress = IRB.CreateCall(
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Intrinsic::getDeclaration(F.getParent(), Intrinsic::returnaddress),
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IRB.getInt32(0));
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IRB.CreateCall(TsanFuncEntry, ReturnAddress);
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for (size_t i = 0, n = RetVec.size(); i < n; ++i) {
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IRBuilder<> IRBRet(RetVec[i]);
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IRBRet.CreateCall(TsanFuncExit);
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}
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Res = true;
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}
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return Res;
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}
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bool ThreadSanitizer::instrumentLoadOrStore(Instruction *I) {
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IRBuilder<> IRB(I);
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bool IsWrite = isa<StoreInst>(*I);
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Value *Addr = IsWrite
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? cast<StoreInst>(I)->getPointerOperand()
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: cast<LoadInst>(I)->getPointerOperand();
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int Idx = getMemoryAccessFuncIndex(Addr);
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if (Idx < 0)
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return false;
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if (IsWrite && isVtableAccess(I)) {
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Value *StoredValue = cast<StoreInst>(I)->getValueOperand();
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IRB.CreateCall2(TsanVptrUpdate,
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IRB.CreatePointerCast(Addr, IRB.getInt8PtrTy()),
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IRB.CreatePointerCast(StoredValue, IRB.getInt8PtrTy()));
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NumInstrumentedVtableWrites++;
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return true;
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}
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Value *OnAccessFunc = IsWrite ? TsanWrite[Idx] : TsanRead[Idx];
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IRB.CreateCall(OnAccessFunc, IRB.CreatePointerCast(Addr, IRB.getInt8PtrTy()));
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if (IsWrite) NumInstrumentedWrites++;
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else NumInstrumentedReads++;
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return true;
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}
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static ConstantInt *createOrdering(IRBuilder<> *IRB, AtomicOrdering ord) {
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uint32_t v = 0;
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switch (ord) {
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case NotAtomic: assert(false);
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case Unordered: // Fall-through.
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case Monotonic: v = 1 << 0; break;
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// case Consume: v = 1 << 1; break; // Not specified yet.
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case Acquire: v = 1 << 2; break;
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case Release: v = 1 << 3; break;
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case AcquireRelease: v = 1 << 4; break;
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case SequentiallyConsistent: v = 1 << 5; break;
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}
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return IRB->getInt32(v);
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}
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bool ThreadSanitizer::instrumentAtomic(Instruction *I) {
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IRBuilder<> IRB(I);
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if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
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Value *Addr = LI->getPointerOperand();
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int Idx = getMemoryAccessFuncIndex(Addr);
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if (Idx < 0)
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return false;
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const size_t ByteSize = 1 << Idx;
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const size_t BitSize = ByteSize * 8;
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Type *Ty = Type::getIntNTy(IRB.getContext(), BitSize);
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Type *PtrTy = Ty->getPointerTo();
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Value *Args[] = {IRB.CreatePointerCast(Addr, PtrTy),
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createOrdering(&IRB, LI->getOrdering())};
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CallInst *C = CallInst::Create(TsanAtomicLoad[Idx],
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ArrayRef<Value*>(Args));
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ReplaceInstWithInst(I, C);
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} else if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
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Value *Addr = SI->getPointerOperand();
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int Idx = getMemoryAccessFuncIndex(Addr);
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if (Idx < 0)
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return false;
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const size_t ByteSize = 1 << Idx;
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const size_t BitSize = ByteSize * 8;
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Type *Ty = Type::getIntNTy(IRB.getContext(), BitSize);
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Type *PtrTy = Ty->getPointerTo();
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Value *Args[] = {IRB.CreatePointerCast(Addr, PtrTy),
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IRB.CreateIntCast(SI->getValueOperand(), Ty, false),
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createOrdering(&IRB, SI->getOrdering())};
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CallInst *C = CallInst::Create(TsanAtomicStore[Idx],
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ArrayRef<Value*>(Args));
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ReplaceInstWithInst(I, C);
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} else if (isa<AtomicRMWInst>(I)) {
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// FIXME: Not yet supported.
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} else if (isa<AtomicCmpXchgInst>(I)) {
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// FIXME: Not yet supported.
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} else if (isa<FenceInst>(I)) {
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// FIXME: Not yet supported.
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}
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return true;
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}
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int ThreadSanitizer::getMemoryAccessFuncIndex(Value *Addr) {
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Type *OrigPtrTy = Addr->getType();
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Type *OrigTy = cast<PointerType>(OrigPtrTy)->getElementType();
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assert(OrigTy->isSized());
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uint32_t TypeSize = TD->getTypeStoreSizeInBits(OrigTy);
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if (TypeSize != 8 && TypeSize != 16 &&
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TypeSize != 32 && TypeSize != 64 && TypeSize != 128) {
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NumAccessesWithBadSize++;
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// Ignore all unusual sizes.
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return -1;
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}
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size_t Idx = CountTrailingZeros_32(TypeSize / 8);
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assert(Idx < kNumberOfAccessSizes);
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return Idx;
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}
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