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Current File : //usr/src/contrib/llvm/lib/Transforms/Instrumentation/GCOVProfiling.cpp |
//===- GCOVProfiling.cpp - Insert edge counters for gcov profiling --------===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This pass implements GCOV-style profiling. When this pass is run it emits // "gcno" files next to the existing source, and instruments the code that runs // to records the edges between blocks that run and emit a complementary "gcda" // file on exit. // //===----------------------------------------------------------------------===// #define DEBUG_TYPE "insert-gcov-profiling" #include "ProfilingUtils.h" #include "llvm/Transforms/Instrumentation.h" #include "llvm/Analysis/DebugInfo.h" #include "llvm/Module.h" #include "llvm/Pass.h" #include "llvm/Instructions.h" #include "llvm/Support/raw_ostream.h" #include "llvm/Support/Debug.h" #include "llvm/Support/DebugLoc.h" #include "llvm/Support/InstIterator.h" #include "llvm/Support/IRBuilder.h" #include "llvm/Support/PathV2.h" #include "llvm/ADT/DenseMap.h" #include "llvm/ADT/Statistic.h" #include "llvm/ADT/STLExtras.h" #include "llvm/ADT/StringExtras.h" #include "llvm/ADT/StringMap.h" #include "llvm/ADT/UniqueVector.h" #include <string> #include <utility> using namespace llvm; namespace { class GCOVProfiler : public ModulePass { public: static char ID; GCOVProfiler() : ModulePass(ID), EmitNotes(true), EmitData(true), Use402Format(false), UseExtraChecksum(false) { initializeGCOVProfilerPass(*PassRegistry::getPassRegistry()); } GCOVProfiler(bool EmitNotes, bool EmitData, bool use402Format = false, bool useExtraChecksum = false) : ModulePass(ID), EmitNotes(EmitNotes), EmitData(EmitData), Use402Format(use402Format), UseExtraChecksum(useExtraChecksum) { assert((EmitNotes || EmitData) && "GCOVProfiler asked to do nothing?"); initializeGCOVProfilerPass(*PassRegistry::getPassRegistry()); } virtual const char *getPassName() const { return "GCOV Profiler"; } private: bool runOnModule(Module &M); // Create the GCNO files for the Module based on DebugInfo. void emitGCNO(); // Modify the program to track transitions along edges and call into the // profiling runtime to emit .gcda files when run. bool emitProfileArcs(); // Get pointers to the functions in the runtime library. Constant *getStartFileFunc(); Constant *getIncrementIndirectCounterFunc(); Constant *getEmitFunctionFunc(); Constant *getEmitArcsFunc(); Constant *getEndFileFunc(); // Create or retrieve an i32 state value that is used to represent the // pred block number for certain non-trivial edges. GlobalVariable *getEdgeStateValue(); // Produce a table of pointers to counters, by predecessor and successor // block number. GlobalVariable *buildEdgeLookupTable(Function *F, GlobalVariable *Counter, const UniqueVector<BasicBlock *> &Preds, const UniqueVector<BasicBlock *> &Succs); // Add the function to write out all our counters to the global destructor // list. void insertCounterWriteout(SmallVector<std::pair<GlobalVariable *, MDNode *>, 8> &); std::string mangleName(DICompileUnit CU, std::string NewStem); bool EmitNotes; bool EmitData; bool Use402Format; bool UseExtraChecksum; Module *M; LLVMContext *Ctx; }; } char GCOVProfiler::ID = 0; INITIALIZE_PASS(GCOVProfiler, "insert-gcov-profiling", "Insert instrumentation for GCOV profiling", false, false) ModulePass *llvm::createGCOVProfilerPass(bool EmitNotes, bool EmitData, bool Use402Format, bool UseExtraChecksum) { return new GCOVProfiler(EmitNotes, EmitData, Use402Format, UseExtraChecksum); } namespace { class GCOVRecord { protected: static const char *LinesTag; static const char *FunctionTag; static const char *BlockTag; static const char *EdgeTag; GCOVRecord() {} void writeBytes(const char *Bytes, int Size) { os->write(Bytes, Size); } void write(uint32_t i) { writeBytes(reinterpret_cast<char*>(&i), 4); } // Returns the length measured in 4-byte blocks that will be used to // represent this string in a GCOV file unsigned lengthOfGCOVString(StringRef s) { // A GCOV string is a length, followed by a NUL, then between 0 and 3 NULs // padding out to the next 4-byte word. The length is measured in 4-byte // words including padding, not bytes of actual string. return (s.size() / 4) + 1; } void writeGCOVString(StringRef s) { uint32_t Len = lengthOfGCOVString(s); write(Len); writeBytes(s.data(), s.size()); // Write 1 to 4 bytes of NUL padding. assert((unsigned)(4 - (s.size() % 4)) > 0); assert((unsigned)(4 - (s.size() % 4)) <= 4); writeBytes("\0\0\0\0", 4 - (s.size() % 4)); } raw_ostream *os; }; const char *GCOVRecord::LinesTag = "\0\0\x45\x01"; const char *GCOVRecord::FunctionTag = "\0\0\0\1"; const char *GCOVRecord::BlockTag = "\0\0\x41\x01"; const char *GCOVRecord::EdgeTag = "\0\0\x43\x01"; class GCOVFunction; class GCOVBlock; // Constructed only by requesting it from a GCOVBlock, this object stores a // list of line numbers and a single filename, representing lines that belong // to the block. class GCOVLines : public GCOVRecord { public: void addLine(uint32_t Line) { Lines.push_back(Line); } uint32_t length() { // Here 2 = 1 for string length + 1 for '0' id#. return lengthOfGCOVString(Filename) + 2 + Lines.size(); } void writeOut() { write(0); writeGCOVString(Filename); for (int i = 0, e = Lines.size(); i != e; ++i) write(Lines[i]); } GCOVLines(StringRef F, raw_ostream *os) : Filename(F) { this->os = os; } private: StringRef Filename; SmallVector<uint32_t, 32> Lines; }; // Represent a basic block in GCOV. Each block has a unique number in the // function, number of lines belonging to each block, and a set of edges to // other blocks. class GCOVBlock : public GCOVRecord { public: GCOVLines &getFile(StringRef Filename) { GCOVLines *&Lines = LinesByFile[Filename]; if (!Lines) { Lines = new GCOVLines(Filename, os); } return *Lines; } void addEdge(GCOVBlock &Successor) { OutEdges.push_back(&Successor); } void writeOut() { uint32_t Len = 3; for (StringMap<GCOVLines *>::iterator I = LinesByFile.begin(), E = LinesByFile.end(); I != E; ++I) { Len += I->second->length(); } writeBytes(LinesTag, 4); write(Len); write(Number); for (StringMap<GCOVLines *>::iterator I = LinesByFile.begin(), E = LinesByFile.end(); I != E; ++I) I->second->writeOut(); write(0); write(0); } ~GCOVBlock() { DeleteContainerSeconds(LinesByFile); } private: friend class GCOVFunction; GCOVBlock(uint32_t Number, raw_ostream *os) : Number(Number) { this->os = os; } uint32_t Number; StringMap<GCOVLines *> LinesByFile; SmallVector<GCOVBlock *, 4> OutEdges; }; // A function has a unique identifier, a checksum (we leave as zero) and a // set of blocks and a map of edges between blocks. This is the only GCOV // object users can construct, the blocks and lines will be rooted here. class GCOVFunction : public GCOVRecord { public: GCOVFunction(DISubprogram SP, raw_ostream *os, bool Use402Format, bool UseExtraChecksum) { this->os = os; Function *F = SP.getFunction(); DEBUG(dbgs() << "Function: " << F->getName() << "\n"); uint32_t i = 0; for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) { Blocks[BB] = new GCOVBlock(i++, os); } ReturnBlock = new GCOVBlock(i++, os); writeBytes(FunctionTag, 4); uint32_t BlockLen = 1 + 1 + 1 + lengthOfGCOVString(SP.getName()) + 1 + lengthOfGCOVString(SP.getFilename()) + 1; if (UseExtraChecksum) ++BlockLen; write(BlockLen); uint32_t Ident = reinterpret_cast<intptr_t>((MDNode*)SP); write(Ident); write(0); // lineno checksum if (UseExtraChecksum) write(0); // cfg checksum writeGCOVString(SP.getName()); writeGCOVString(SP.getFilename()); write(SP.getLineNumber()); } ~GCOVFunction() { DeleteContainerSeconds(Blocks); delete ReturnBlock; } GCOVBlock &getBlock(BasicBlock *BB) { return *Blocks[BB]; } GCOVBlock &getReturnBlock() { return *ReturnBlock; } void writeOut() { // Emit count of blocks. writeBytes(BlockTag, 4); write(Blocks.size() + 1); for (int i = 0, e = Blocks.size() + 1; i != e; ++i) { write(0); // No flags on our blocks. } DEBUG(dbgs() << Blocks.size() << " blocks.\n"); // Emit edges between blocks. for (DenseMap<BasicBlock *, GCOVBlock *>::iterator I = Blocks.begin(), E = Blocks.end(); I != E; ++I) { GCOVBlock &Block = *I->second; if (Block.OutEdges.empty()) continue; writeBytes(EdgeTag, 4); write(Block.OutEdges.size() * 2 + 1); write(Block.Number); for (int i = 0, e = Block.OutEdges.size(); i != e; ++i) { DEBUG(dbgs() << Block.Number << " -> " << Block.OutEdges[i]->Number << "\n"); write(Block.OutEdges[i]->Number); write(0); // no flags } } // Emit lines for each block. for (DenseMap<BasicBlock *, GCOVBlock *>::iterator I = Blocks.begin(), E = Blocks.end(); I != E; ++I) { I->second->writeOut(); } } private: DenseMap<BasicBlock *, GCOVBlock *> Blocks; GCOVBlock *ReturnBlock; }; } std::string GCOVProfiler::mangleName(DICompileUnit CU, std::string NewStem) { if (NamedMDNode *GCov = M->getNamedMetadata("llvm.gcov")) { for (int i = 0, e = GCov->getNumOperands(); i != e; ++i) { MDNode *N = GCov->getOperand(i); if (N->getNumOperands() != 2) continue; MDString *GCovFile = dyn_cast<MDString>(N->getOperand(0)); MDNode *CompileUnit = dyn_cast<MDNode>(N->getOperand(1)); if (!GCovFile || !CompileUnit) continue; if (CompileUnit == CU) { SmallString<128> Filename = GCovFile->getString(); sys::path::replace_extension(Filename, NewStem); return Filename.str(); } } } SmallString<128> Filename = CU.getFilename(); sys::path::replace_extension(Filename, NewStem); return sys::path::filename(Filename.str()); } bool GCOVProfiler::runOnModule(Module &M) { this->M = &M; Ctx = &M.getContext(); if (EmitNotes) emitGCNO(); if (EmitData) return emitProfileArcs(); return false; } void GCOVProfiler::emitGCNO() { NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu"); if (!CU_Nodes) return; for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) { // Each compile unit gets its own .gcno file. This means that whether we run // this pass over the original .o's as they're produced, or run it after // LTO, we'll generate the same .gcno files. DICompileUnit CU(CU_Nodes->getOperand(i)); std::string ErrorInfo; raw_fd_ostream out(mangleName(CU, "gcno").c_str(), ErrorInfo, raw_fd_ostream::F_Binary); if (!Use402Format) out.write("oncg*404MVLL", 12); else out.write("oncg*204MVLL", 12); DIArray SPs = CU.getSubprograms(); for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i) { DISubprogram SP(SPs.getElement(i)); if (!SP.Verify()) continue; Function *F = SP.getFunction(); if (!F) continue; GCOVFunction Func(SP, &out, Use402Format, UseExtraChecksum); for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) { GCOVBlock &Block = Func.getBlock(BB); TerminatorInst *TI = BB->getTerminator(); if (int successors = TI->getNumSuccessors()) { for (int i = 0; i != successors; ++i) { Block.addEdge(Func.getBlock(TI->getSuccessor(i))); } } else if (isa<ReturnInst>(TI)) { Block.addEdge(Func.getReturnBlock()); } uint32_t Line = 0; for (BasicBlock::iterator I = BB->begin(), IE = BB->end(); I != IE; ++I) { const DebugLoc &Loc = I->getDebugLoc(); if (Loc.isUnknown()) continue; if (Line == Loc.getLine()) continue; Line = Loc.getLine(); if (SP != getDISubprogram(Loc.getScope(*Ctx))) continue; GCOVLines &Lines = Block.getFile(SP.getFilename()); Lines.addLine(Loc.getLine()); } } Func.writeOut(); } out.write("\0\0\0\0\0\0\0\0", 8); // EOF out.close(); } } bool GCOVProfiler::emitProfileArcs() { NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu"); if (!CU_Nodes) return false; bool Result = false; for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) { DICompileUnit CU(CU_Nodes->getOperand(i)); DIArray SPs = CU.getSubprograms(); SmallVector<std::pair<GlobalVariable *, MDNode *>, 8> CountersBySP; for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i) { DISubprogram SP(SPs.getElement(i)); if (!SP.Verify()) continue; Function *F = SP.getFunction(); if (!F) continue; if (!Result) Result = true; unsigned Edges = 0; for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) { TerminatorInst *TI = BB->getTerminator(); if (isa<ReturnInst>(TI)) ++Edges; else Edges += TI->getNumSuccessors(); } ArrayType *CounterTy = ArrayType::get(Type::getInt64Ty(*Ctx), Edges); GlobalVariable *Counters = new GlobalVariable(*M, CounterTy, false, GlobalValue::InternalLinkage, Constant::getNullValue(CounterTy), "__llvm_gcov_ctr", 0, false, 0); CountersBySP.push_back(std::make_pair(Counters, (MDNode*)SP)); UniqueVector<BasicBlock *> ComplexEdgePreds; UniqueVector<BasicBlock *> ComplexEdgeSuccs; unsigned Edge = 0; for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) { TerminatorInst *TI = BB->getTerminator(); int Successors = isa<ReturnInst>(TI) ? 1 : TI->getNumSuccessors(); if (Successors) { IRBuilder<> Builder(TI); if (Successors == 1) { Value *Counter = Builder.CreateConstInBoundsGEP2_64(Counters, 0, Edge); Value *Count = Builder.CreateLoad(Counter); Count = Builder.CreateAdd(Count, ConstantInt::get(Type::getInt64Ty(*Ctx),1)); Builder.CreateStore(Count, Counter); } else if (BranchInst *BI = dyn_cast<BranchInst>(TI)) { Value *Sel = Builder.CreateSelect( BI->getCondition(), ConstantInt::get(Type::getInt64Ty(*Ctx), Edge), ConstantInt::get(Type::getInt64Ty(*Ctx), Edge + 1)); SmallVector<Value *, 2> Idx; Idx.push_back(Constant::getNullValue(Type::getInt64Ty(*Ctx))); Idx.push_back(Sel); Value *Counter = Builder.CreateInBoundsGEP(Counters, Idx); Value *Count = Builder.CreateLoad(Counter); Count = Builder.CreateAdd(Count, ConstantInt::get(Type::getInt64Ty(*Ctx),1)); Builder.CreateStore(Count, Counter); } else { ComplexEdgePreds.insert(BB); for (int i = 0; i != Successors; ++i) ComplexEdgeSuccs.insert(TI->getSuccessor(i)); } Edge += Successors; } } if (!ComplexEdgePreds.empty()) { GlobalVariable *EdgeTable = buildEdgeLookupTable(F, Counters, ComplexEdgePreds, ComplexEdgeSuccs); GlobalVariable *EdgeState = getEdgeStateValue(); Type *Int32Ty = Type::getInt32Ty(*Ctx); for (int i = 0, e = ComplexEdgePreds.size(); i != e; ++i) { IRBuilder<> Builder(ComplexEdgePreds[i+1]->getTerminator()); Builder.CreateStore(ConstantInt::get(Int32Ty, i), EdgeState); } for (int i = 0, e = ComplexEdgeSuccs.size(); i != e; ++i) { // call runtime to perform increment BasicBlock::iterator InsertPt = ComplexEdgeSuccs[i+1]->getFirstInsertionPt(); IRBuilder<> Builder(InsertPt); Value *CounterPtrArray = Builder.CreateConstInBoundsGEP2_64(EdgeTable, 0, i * ComplexEdgePreds.size()); Builder.CreateCall2(getIncrementIndirectCounterFunc(), EdgeState, CounterPtrArray); // clear the predecessor number Builder.CreateStore(ConstantInt::get(Int32Ty, 0xffffffff), EdgeState); } } } insertCounterWriteout(CountersBySP); } return Result; } // All edges with successors that aren't branches are "complex", because it // requires complex logic to pick which counter to update. GlobalVariable *GCOVProfiler::buildEdgeLookupTable( Function *F, GlobalVariable *Counters, const UniqueVector<BasicBlock *> &Preds, const UniqueVector<BasicBlock *> &Succs) { // TODO: support invoke, threads. We rely on the fact that nothing can modify // the whole-Module pred edge# between the time we set it and the time we next // read it. Threads and invoke make this untrue. // emit [(succs * preds) x i64*], logically [succ x [pred x i64*]]. Type *Int64PtrTy = Type::getInt64PtrTy(*Ctx); ArrayType *EdgeTableTy = ArrayType::get( Int64PtrTy, Succs.size() * Preds.size()); Constant **EdgeTable = new Constant*[Succs.size() * Preds.size()]; Constant *NullValue = Constant::getNullValue(Int64PtrTy); for (int i = 0, ie = Succs.size() * Preds.size(); i != ie; ++i) EdgeTable[i] = NullValue; unsigned Edge = 0; for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) { TerminatorInst *TI = BB->getTerminator(); int Successors = isa<ReturnInst>(TI) ? 1 : TI->getNumSuccessors(); if (Successors > 1 && !isa<BranchInst>(TI) && !isa<ReturnInst>(TI)) { for (int i = 0; i != Successors; ++i) { BasicBlock *Succ = TI->getSuccessor(i); IRBuilder<> builder(Succ); Value *Counter = builder.CreateConstInBoundsGEP2_64(Counters, 0, Edge + i); EdgeTable[((Succs.idFor(Succ)-1) * Preds.size()) + (Preds.idFor(BB)-1)] = cast<Constant>(Counter); } } Edge += Successors; } ArrayRef<Constant*> V(&EdgeTable[0], Succs.size() * Preds.size()); GlobalVariable *EdgeTableGV = new GlobalVariable( *M, EdgeTableTy, true, GlobalValue::InternalLinkage, ConstantArray::get(EdgeTableTy, V), "__llvm_gcda_edge_table"); EdgeTableGV->setUnnamedAddr(true); return EdgeTableGV; } Constant *GCOVProfiler::getStartFileFunc() { FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Type::getInt8PtrTy(*Ctx), false); return M->getOrInsertFunction("llvm_gcda_start_file", FTy); } Constant *GCOVProfiler::getIncrementIndirectCounterFunc() { Type *Args[] = { Type::getInt32PtrTy(*Ctx), // uint32_t *predecessor Type::getInt64PtrTy(*Ctx)->getPointerTo(), // uint64_t **state_table_row }; FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false); return M->getOrInsertFunction("llvm_gcda_increment_indirect_counter", FTy); } Constant *GCOVProfiler::getEmitFunctionFunc() { Type *Args[2] = { Type::getInt32Ty(*Ctx), // uint32_t ident Type::getInt8PtrTy(*Ctx), // const char *function_name }; FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false); return M->getOrInsertFunction("llvm_gcda_emit_function", FTy); } Constant *GCOVProfiler::getEmitArcsFunc() { Type *Args[] = { Type::getInt32Ty(*Ctx), // uint32_t num_counters Type::getInt64PtrTy(*Ctx), // uint64_t *counters }; FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false); return M->getOrInsertFunction("llvm_gcda_emit_arcs", FTy); } Constant *GCOVProfiler::getEndFileFunc() { FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false); return M->getOrInsertFunction("llvm_gcda_end_file", FTy); } GlobalVariable *GCOVProfiler::getEdgeStateValue() { GlobalVariable *GV = M->getGlobalVariable("__llvm_gcov_global_state_pred"); if (!GV) { GV = new GlobalVariable(*M, Type::getInt32Ty(*Ctx), false, GlobalValue::InternalLinkage, ConstantInt::get(Type::getInt32Ty(*Ctx), 0xffffffff), "__llvm_gcov_global_state_pred"); GV->setUnnamedAddr(true); } return GV; } void GCOVProfiler::insertCounterWriteout( SmallVector<std::pair<GlobalVariable *, MDNode *>, 8> &CountersBySP) { FunctionType *WriteoutFTy = FunctionType::get(Type::getVoidTy(*Ctx), false); Function *WriteoutF = Function::Create(WriteoutFTy, GlobalValue::InternalLinkage, "__llvm_gcov_writeout", M); WriteoutF->setUnnamedAddr(true); BasicBlock *BB = BasicBlock::Create(*Ctx, "", WriteoutF); IRBuilder<> Builder(BB); Constant *StartFile = getStartFileFunc(); Constant *EmitFunction = getEmitFunctionFunc(); Constant *EmitArcs = getEmitArcsFunc(); Constant *EndFile = getEndFileFunc(); NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu"); if (CU_Nodes) { for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) { DICompileUnit compile_unit(CU_Nodes->getOperand(i)); std::string FilenameGcda = mangleName(compile_unit, "gcda"); Builder.CreateCall(StartFile, Builder.CreateGlobalStringPtr(FilenameGcda)); for (SmallVector<std::pair<GlobalVariable *, MDNode *>, 8>::iterator I = CountersBySP.begin(), E = CountersBySP.end(); I != E; ++I) { DISubprogram SP(I->second); intptr_t ident = reinterpret_cast<intptr_t>(I->second); Builder.CreateCall2(EmitFunction, ConstantInt::get(Type::getInt32Ty(*Ctx), ident), Builder.CreateGlobalStringPtr(SP.getName())); GlobalVariable *GV = I->first; unsigned Arcs = cast<ArrayType>(GV->getType()->getElementType())->getNumElements(); Builder.CreateCall2(EmitArcs, ConstantInt::get(Type::getInt32Ty(*Ctx), Arcs), Builder.CreateConstGEP2_64(GV, 0, 0)); } Builder.CreateCall(EndFile); } } Builder.CreateRetVoid(); InsertProfilingShutdownCall(WriteoutF, M); }