lib/Transforms/Instrumentation/GCOVProfiling.cpp

   1 //===- GCOVProfiling.cpp - Insert edge counters for gcov profiling --------===//
   2 //
   3 //                      The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This pass implements GCOV-style profiling. When this pass is run it emits
  11 // "gcno" files next to the existing source, and instruments the code that runs
  12 // to records the edges between blocks that run and emit a complementary "gcda"
  13 // file on exit.
  14 //
  15 //===----------------------------------------------------------------------===//
  16
  17 #define DEBUG_TYPE "insert-gcov-profiling"
  18
  19 #include "ProfilingUtils.h"
  20 #include "llvm/Transforms/Instrumentation.h"
  21 #include "llvm/Analysis/DebugInfo.h"
  22 #include "llvm/Module.h"
  23 #include "llvm/Pass.h"
  24 #include "llvm/Instructions.h"
  25 #include "llvm/Support/raw_ostream.h"
  26 #include "llvm/Support/Debug.h"
  27 #include "llvm/Support/DebugLoc.h"
  28 #include "llvm/Support/InstIterator.h"
  29 #include "llvm/Support/IRBuilder.h"
  30 #include "llvm/Support/PathV2.h"
  31 #include "llvm/ADT/DenseMap.h"
  32 #include "llvm/ADT/Statistic.h"
  33 #include "llvm/ADT/STLExtras.h"
  34 #include "llvm/ADT/StringExtras.h"
  35 #include "llvm/ADT/StringMap.h"
  36 #include "llvm/ADT/UniqueVector.h"
  37 #include <string>
  38 #include <utility>
  39 using namespace llvm;
  40
  41 namespace {
  42   class GCOVProfiler : public ModulePass {
  43   public:
  44     static char ID;
  45     GCOVProfiler()
  46         : ModulePass(ID), EmitNotes(true), EmitData(true), Use402Format(false) {
  47       initializeGCOVProfilerPass(*PassRegistry::getPassRegistry());
  48     }
  49     GCOVProfiler(bool EmitNotes, bool EmitData, bool use402Format = false)
  50         : ModulePass(ID), EmitNotes(EmitNotes), EmitData(EmitData),
  51           Use402Format(use402Format) {
  52       assert((EmitNotes || EmitData) && "GCOVProfiler asked to do nothing?");
  53       initializeGCOVProfilerPass(*PassRegistry::getPassRegistry());
  54     }
  55     virtual const char *getPassName() const {
  56       return "GCOV Profiler";
  57     }
  58
  59   private:
  60     bool runOnModule(Module &M);
  61
  62     // Create the GCNO files for the Module based on DebugInfo.
  63     void emitGCNO(DebugInfoFinder &DIF);
  64
  65     // Modify the program to track transitions along edges and call into the
  66     // profiling runtime to emit .gcda files when run.
  67     bool emitProfileArcs(DebugInfoFinder &DIF);
  68
  69     // Get pointers to the functions in the runtime library.
  70     Constant *getStartFileFunc();
  71     Constant *getIncrementIndirectCounterFunc();
  72     Constant *getEmitFunctionFunc();
  73     Constant *getEmitArcsFunc();
  74     Constant *getEndFileFunc();
  75
  76     // Create or retrieve an i32 state value that is used to represent the
  77     // pred block number for certain non-trivial edges.
  78     GlobalVariable *getEdgeStateValue();
  79
  80     // Produce a table of pointers to counters, by predecessor and successor
  81     // block number.
  82     GlobalVariable *buildEdgeLookupTable(Function *F,
  83                                          GlobalVariable *Counter,
  84                                          const UniqueVector<BasicBlock *> &Preds,
  85                                          const UniqueVector<BasicBlock *> &Succs);
  86
  87     // Add the function to write out all our counters to the global destructor
  88     // list.
  89     void insertCounterWriteout(DebugInfoFinder &,
  90                                SmallVector<std::pair<GlobalVariable *,
  91                                                      MDNode *>, 8> &);
  92
  93     std::string mangleName(DICompileUnit CU, std::string NewStem);
  94
  95     bool EmitNotes;
  96     bool EmitData;
  97     bool Use402Format;
  98
  99     Module *M;
 100     LLVMContext *Ctx;
 101   };
 102 }
 103
 104 char GCOVProfiler::ID = 0;
 105 INITIALIZE_PASS(GCOVProfiler, "insert-gcov-profiling",
 106                 "Insert instrumentation for GCOV profiling", false, false)
 107
 108 ModulePass *llvm::createGCOVProfilerPass(bool EmitNotes, bool EmitData,
 109                                          bool Use402Format) {
 110   return new GCOVProfiler(EmitNotes, EmitData, Use402Format);
 111 }
 112
 113 static DISubprogram findSubprogram(DIScope Scope) {
 114   while (!Scope.isSubprogram()) {
 115     assert(Scope.isLexicalBlock() &&
 116            "Debug location not lexical block or subprogram");
 117     Scope = DILexicalBlock(Scope).getContext();
 118   }
 119   return DISubprogram(Scope);
 120 }
 121
 122 namespace {
 123   class GCOVRecord {
 124    protected:
 125     static const char *LinesTag;
 126     static const char *FunctionTag;
 127     static const char *BlockTag;
 128     static const char *EdgeTag;
 129
 130     GCOVRecord() {}
 131
 132     void writeBytes(const char *Bytes, int Size) {
 133       os->write(Bytes, Size);
 134     }
 135
 136     void write(uint32_t i) {
 137       writeBytes(reinterpret_cast<char*>(&i), 4);
 138     }
 139
 140     // Returns the length measured in 4-byte blocks that will be used to
 141     // represent this string in a GCOV file
 142     unsigned lengthOfGCOVString(StringRef s) {
 143       // A GCOV string is a length, followed by a NUL, then between 0 and 3 NULs
 144       // padding out to the next 4-byte word. The length is measured in 4-byte
 145       // words including padding, not bytes of actual string.
 146       return (s.size() / 4) + 1;
 147     }
 148
 149     void writeGCOVString(StringRef s) {
 150       uint32_t Len = lengthOfGCOVString(s);
 151       write(Len);
 152       writeBytes(s.data(), s.size());
 153
 154       // Write 1 to 4 bytes of NUL padding.
 155       assert((unsigned)(4 - (s.size() % 4)) > 0);
 156       assert((unsigned)(4 - (s.size() % 4)) <= 4);
 157       writeBytes("\0\0\0\0", 4 - (s.size() % 4));
 158     }
 159
 160     raw_ostream *os;
 161   };
 162   const char *GCOVRecord::LinesTag = "\0\0\x45\x01";
 163   const char *GCOVRecord::FunctionTag = "\0\0\0\1";
 164   const char *GCOVRecord::BlockTag = "\0\0\x41\x01";
 165   const char *GCOVRecord::EdgeTag = "\0\0\x43\x01";
 166
 167   class GCOVFunction;
 168   class GCOVBlock;
 169
 170   // Constructed only by requesting it from a GCOVBlock, this object stores a
 171   // list of line numbers and a single filename, representing lines that belong
 172   // to the block.
 173   class GCOVLines : public GCOVRecord {
 174    public:
 175     void addLine(uint32_t Line) {
 176       Lines.push_back(Line);
 177     }
 178
 179     uint32_t length() {
 180       return lengthOfGCOVString(Filename) + 2 + Lines.size();
 181     }
 182
 183    private:
 184     friend class GCOVBlock;
 185
 186     GCOVLines(std::string Filename, raw_ostream *os)
 187         : Filename(Filename) {
 188       this->os = os;
 189     }
 190
 191     std::string Filename;
 192     SmallVector<uint32_t, 32> Lines;
 193   };
 194
 195   // Represent a basic block in GCOV. Each block has a unique number in the
 196   // function, number of lines belonging to each block, and a set of edges to
 197   // other blocks.
 198   class GCOVBlock : public GCOVRecord {
 199    public:
 200     GCOVLines &getFile(std::string Filename) {
 201       GCOVLines *&Lines = LinesByFile[Filename];
 202       if (!Lines) {
 203         Lines = new GCOVLines(Filename, os);
 204       }
 205       return *Lines;
 206     }
 207
 208     void addEdge(GCOVBlock &Successor) {
 209       OutEdges.push_back(&Successor);
 210     }
 211
 212     void writeOut() {
 213       uint32_t Len = 3;
 214       for (StringMap<GCOVLines *>::iterator I = LinesByFile.begin(),
 215                E = LinesByFile.end(); I != E; ++I) {
 216         Len += I->second->length();
 217       }
 218
 219       writeBytes(LinesTag, 4);
 220       write(Len);
 221       write(Number);
 222       for (StringMap<GCOVLines *>::iterator I = LinesByFile.begin(),
 223                E = LinesByFile.end(); I != E; ++I) {
 224         write(0);
 225         writeGCOVString(I->second->Filename);
 226         for (int i = 0, e = I->second->Lines.size(); i != e; ++i) {
 227           write(I->second->Lines[i]);
 228         }
 229       }
 230       write(0);
 231       write(0);
 232     }
 233
 234     ~GCOVBlock() {
 235       DeleteContainerSeconds(LinesByFile);
 236     }
 237
 238    private:
 239     friend class GCOVFunction;
 240
 241     GCOVBlock(uint32_t Number, raw_ostream *os)
 242         : Number(Number) {
 243       this->os = os;
 244     }
 245
 246     uint32_t Number;
 247     StringMap<GCOVLines *> LinesByFile;
 248     SmallVector<GCOVBlock *, 4> OutEdges;
 249   };
 250
 251   // A function has a unique identifier, a checksum (we leave as zero) and a
 252   // set of blocks and a map of edges between blocks. This is the only GCOV
 253   // object users can construct, the blocks and lines will be rooted here.
 254   class GCOVFunction : public GCOVRecord {
 255    public:
 256     GCOVFunction(DISubprogram SP, raw_ostream *os, bool Use402Format) {
 257       this->os = os;
 258
 259       Function *F = SP.getFunction();
 260       uint32_t i = 0;
 261       for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
 262         Blocks[BB] = new GCOVBlock(i++, os);
 263       }
 264       ReturnBlock = new GCOVBlock(i++, os);
 265
 266       writeBytes(FunctionTag, 4);
 267       uint32_t BlockLen = 1 + 1 + 1 + lengthOfGCOVString(SP.getName()) +
 268           1 + lengthOfGCOVString(SP.getFilename()) + 1;
 269       if (!Use402Format)
 270         ++BlockLen; // For second checksum.
 271       write(BlockLen);
 272       uint32_t Ident = reinterpret_cast<intptr_t>((MDNode*)SP);
 273       write(Ident);
 274       write(0);  // checksum #1
 275       if (!Use402Format)
 276         write(0);  // checksum #2
 277       writeGCOVString(SP.getName());
 278       writeGCOVString(SP.getFilename());
 279       write(SP.getLineNumber());
 280     }
 281
 282     ~GCOVFunction() {
 283       DeleteContainerSeconds(Blocks);
 284       delete ReturnBlock;
 285     }
 286
 287     GCOVBlock &getBlock(BasicBlock *BB) {
 288       return *Blocks[BB];
 289     }
 290
 291     GCOVBlock &getReturnBlock() {
 292       return *ReturnBlock;
 293     }
 294
 295     void writeOut() {
 296       // Emit count of blocks.
 297       writeBytes(BlockTag, 4);
 298       write(Blocks.size() + 1);
 299       for (int i = 0, e = Blocks.size() + 1; i != e; ++i) {
 300         write(0);  // No flags on our blocks.
 301       }
 302
 303       // Emit edges between blocks.
 304       for (DenseMap<BasicBlock *, GCOVBlock *>::iterator I = Blocks.begin(),
 305                E = Blocks.end(); I != E; ++I) {
 306         GCOVBlock &Block = *I->second;
 307         if (Block.OutEdges.empty()) continue;
 308
 309         writeBytes(EdgeTag, 4);
 310         write(Block.OutEdges.size() * 2 + 1);
 311         write(Block.Number);
 312         for (int i = 0, e = Block.OutEdges.size(); i != e; ++i) {
 313           write(Block.OutEdges[i]->Number);
 314           write(0);  // no flags
 315         }
 316       }
 317
 318       // Emit lines for each block.
 319       for (DenseMap<BasicBlock *, GCOVBlock *>::iterator I = Blocks.begin(),
 320                E = Blocks.end(); I != E; ++I) {
 321         I->second->writeOut();
 322       }
 323     }
 324
 325    private:
 326     DenseMap<BasicBlock *, GCOVBlock *> Blocks;
 327     GCOVBlock *ReturnBlock;
 328   };
 329 }
 330
 331 std::string GCOVProfiler::mangleName(DICompileUnit CU, std::string NewStem) {
 332   if (NamedMDNode *GCov = M->getNamedMetadata("llvm.gcov")) {
 333     for (int i = 0, e = GCov->getNumOperands(); i != e; ++i) {
 334       MDNode *N = GCov->getOperand(i);
 335       if (N->getNumOperands() != 2) continue;
 336       MDString *GCovFile = dyn_cast<MDString>(N->getOperand(0));
 337       MDNode *CompileUnit = dyn_cast<MDNode>(N->getOperand(1));
 338       if (!GCovFile || !CompileUnit) continue;
 339       if (CompileUnit == CU) {
 340         SmallString<128> Filename = GCovFile->getString();
 341         sys::path::replace_extension(Filename, NewStem);
 342         return Filename.str();
 343       }
 344     }
 345   }
 346
 347   SmallString<128> Filename = CU.getFilename();
 348   sys::path::replace_extension(Filename, NewStem);
 349   return sys::path::filename(Filename.str());
 350 }
 351
 352 bool GCOVProfiler::runOnModule(Module &M) {
 353   this->M = &M;
 354   Ctx = &M.getContext();
 355
 356   DebugInfoFinder DIF;
 357   DIF.processModule(M);
 358
 359   if (EmitNotes) emitGCNO(DIF);
 360   if (EmitData) return emitProfileArcs(DIF);
 361   return false;
 362 }
 363
 364 void GCOVProfiler::emitGCNO(DebugInfoFinder &DIF) {
 365   DenseMap<const MDNode *, raw_fd_ostream *> GcnoFiles;
 366   for (DebugInfoFinder::iterator I = DIF.compile_unit_begin(),
 367            E = DIF.compile_unit_end(); I != E; ++I) {
 368     // Each compile unit gets its own .gcno file. This means that whether we run
 369     // this pass over the original .o's as they're produced, or run it after
 370     // LTO, we'll generate the same .gcno files.
 371
 372     DICompileUnit CU(*I);
 373     raw_fd_ostream *&out = GcnoFiles[CU];
 374     std::string ErrorInfo;
 375     out = new raw_fd_ostream(mangleName(CU, "gcno").c_str(), ErrorInfo,
 376                              raw_fd_ostream::F_Binary);
 377     if (!Use402Format)
 378       out->write("oncg*404MVLL", 12);
 379     else
 380       out->write("oncg*402MVLL", 12);
 381   }
 382
 383   for (DebugInfoFinder::iterator SPI = DIF.subprogram_begin(),
 384            SPE = DIF.subprogram_end(); SPI != SPE; ++SPI) {
 385     DISubprogram SP(*SPI);
 386     raw_fd_ostream *&os = GcnoFiles[SP.getCompileUnit()];
 387
 388     Function *F = SP.getFunction();
 389     if (!F) continue;
 390     GCOVFunction Func(SP, os, Use402Format);
 391
 392     for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
 393       GCOVBlock &Block = Func.getBlock(BB);
 394       TerminatorInst *TI = BB->getTerminator();
 395       if (int successors = TI->getNumSuccessors()) {
 396         for (int i = 0; i != successors; ++i) {
 397           Block.addEdge(Func.getBlock(TI->getSuccessor(i)));
 398         }
 399       } else if (isa<ReturnInst>(TI)) {
 400         Block.addEdge(Func.getReturnBlock());
 401       }
 402
 403       uint32_t Line = 0;
 404       for (BasicBlock::iterator I = BB->begin(), IE = BB->end(); I != IE; ++I) {
 405         const DebugLoc &Loc = I->getDebugLoc();
 406         if (Loc.isUnknown()) continue;
 407         if (Line == Loc.getLine()) continue;
 408         Line = Loc.getLine();
 409         if (SP != findSubprogram(DIScope(Loc.getScope(*Ctx)))) continue;
 410
 411         GCOVLines &Lines = Block.getFile(SP.getFilename());
 412         Lines.addLine(Loc.getLine());
 413       }
 414     }
 415     Func.writeOut();
 416   }
 417
 418   for (DenseMap<const MDNode *, raw_fd_ostream *>::iterator
 419            I = GcnoFiles.begin(), E = GcnoFiles.end(); I != E; ++I) {
 420     raw_fd_ostream *&out = I->second;
 421     out->write("\0\0\0\0\0\0\0\0", 8);  // EOF
 422     out->close();
 423     delete out;
 424   }
 425 }
 426
 427 bool GCOVProfiler::emitProfileArcs(DebugInfoFinder &DIF) {
 428   if (DIF.subprogram_begin() == DIF.subprogram_end())
 429     return false;
 430
 431   SmallVector<std::pair<GlobalVariable *, MDNode *>, 8> CountersBySP;
 432   for (DebugInfoFinder::iterator SPI = DIF.subprogram_begin(),
 433            SPE = DIF.subprogram_end(); SPI != SPE; ++SPI) {
 434     DISubprogram SP(*SPI);
 435     Function *F = SP.getFunction();
 436     if (!F) continue;
 437
 438     unsigned Edges = 0;
 439     for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
 440       TerminatorInst *TI = BB->getTerminator();
 441       if (isa<ReturnInst>(TI))
 442         ++Edges;
 443       else
 444         Edges += TI->getNumSuccessors();
 445     }
 446
 447     const ArrayType *CounterTy =
 448         ArrayType::get(Type::getInt64Ty(*Ctx), Edges);
 449     GlobalVariable *Counters =
 450         new GlobalVariable(*M, CounterTy, false,
 451                            GlobalValue::InternalLinkage,
 452                            Constant::getNullValue(CounterTy),
 453                            "__llvm_gcov_ctr", 0, false, 0);
 454     CountersBySP.push_back(std::make_pair(Counters, (MDNode*)SP));
 455
 456     UniqueVector<BasicBlock *> ComplexEdgePreds;
 457     UniqueVector<BasicBlock *> ComplexEdgeSuccs;
 458
 459     unsigned Edge = 0;
 460     for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
 461       TerminatorInst *TI = BB->getTerminator();
 462       int Successors = isa<ReturnInst>(TI) ? 1 : TI->getNumSuccessors();
 463       if (Successors) {
 464         IRBuilder<> Builder(TI);
 465
 466         if (Successors == 1) {
 467           Value *Counter = Builder.CreateConstInBoundsGEP2_64(Counters, 0,
 468                                                               Edge);
 469           Value *Count = Builder.CreateLoad(Counter);
 470           Count = Builder.CreateAdd(Count,
 471                                     ConstantInt::get(Type::getInt64Ty(*Ctx),1));
 472           Builder.CreateStore(Count, Counter);
 473         } else if (BranchInst *BI = dyn_cast<BranchInst>(TI)) {
 474           Value *Sel = Builder.CreateSelect(
 475               BI->getCondition(),
 476               ConstantInt::get(Type::getInt64Ty(*Ctx), Edge),
 477               ConstantInt::get(Type::getInt64Ty(*Ctx), Edge + 1));
 478           SmallVector<Value *, 2> Idx;
 479           Idx.push_back(Constant::getNullValue(Type::getInt64Ty(*Ctx)));
 480           Idx.push_back(Sel);
 481           Value *Counter = Builder.CreateInBoundsGEP(Counters,
 482                                                      Idx.begin(), Idx.end());
 483           Value *Count = Builder.CreateLoad(Counter);
 484           Count = Builder.CreateAdd(Count,
 485                                     ConstantInt::get(Type::getInt64Ty(*Ctx),1));
 486           Builder.CreateStore(Count, Counter);
 487         } else {
 488           ComplexEdgePreds.insert(BB);
 489           for (int i = 0; i != Successors; ++i)
 490             ComplexEdgeSuccs.insert(TI->getSuccessor(i));
 491         }
 492         Edge += Successors;
 493       }
 494     }
 495
 496     if (!ComplexEdgePreds.empty()) {
 497       GlobalVariable *EdgeTable =
 498           buildEdgeLookupTable(F, Counters,
 499                                ComplexEdgePreds, ComplexEdgeSuccs);
 500       GlobalVariable *EdgeState = getEdgeStateValue();
 501
 502       const Type *Int32Ty = Type::getInt32Ty(*Ctx);
 503       for (int i = 0, e = ComplexEdgePreds.size(); i != e; ++i) {
 504         IRBuilder<> Builder(ComplexEdgePreds[i+1]->getTerminator());
 505         Builder.CreateStore(ConstantInt::get(Int32Ty, i), EdgeState);
 506       }
 507       for (int i = 0, e = ComplexEdgeSuccs.size(); i != e; ++i) {
 508         // call runtime to perform increment
 509         IRBuilder<> Builder(ComplexEdgeSuccs[i+1]->getFirstNonPHI());
 510         Value *CounterPtrArray =
 511             Builder.CreateConstInBoundsGEP2_64(EdgeTable, 0,
 512                                                i * ComplexEdgePreds.size());
 513         Builder.CreateCall2(getIncrementIndirectCounterFunc(),
 514                             EdgeState, CounterPtrArray);
 515         // clear the predecessor number
 516         Builder.CreateStore(ConstantInt::get(Int32Ty, 0xffffffff), EdgeState);
 517       }
 518     }
 519   }
 520
 521   insertCounterWriteout(DIF, CountersBySP);
 522
 523   return true;
 524 }
 525
 526 // All edges with successors that aren't branches are "complex", because it
 527 // requires complex logic to pick which counter to update.
 528 GlobalVariable *GCOVProfiler::buildEdgeLookupTable(
 529     Function *F,
 530     GlobalVariable *Counters,
 531     const UniqueVector<BasicBlock *> &Preds,
 532     const UniqueVector<BasicBlock *> &Succs) {
 533   // TODO: support invoke, threads. We rely on the fact that nothing can modify
 534   // the whole-Module pred edge# between the time we set it and the time we next
 535   // read it. Threads and invoke make this untrue.
 536
 537   // emit [(succs * preds) x i64*], logically [succ x [pred x i64*]].
 538   const Type *Int64PtrTy = Type::getInt64PtrTy(*Ctx);
 539   const ArrayType *EdgeTableTy = ArrayType::get(
 540       Int64PtrTy, Succs.size() * Preds.size());
 541
 542   Constant **EdgeTable = new Constant*[Succs.size() * Preds.size()];
 543   Constant *NullValue = Constant::getNullValue(Int64PtrTy);
 544   for (int i = 0, ie = Succs.size() * Preds.size(); i != ie; ++i)
 545     EdgeTable[i] = NullValue;
 546
 547   unsigned Edge = 0;
 548   for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
 549     TerminatorInst *TI = BB->getTerminator();
 550     int Successors = isa<ReturnInst>(TI) ? 1 : TI->getNumSuccessors();
 551     if (Successors > 1 && !isa<BranchInst>(TI) && !isa<ReturnInst>(TI)) {
 552       for (int i = 0; i != Successors; ++i) {
 553         BasicBlock *Succ = TI->getSuccessor(i);
 554         IRBuilder<> builder(Succ);
 555         Value *Counter = builder.CreateConstInBoundsGEP2_64(Counters, 0,
 556                                                             Edge + i);
 557         EdgeTable[((Succs.idFor(Succ)-1) * Preds.size()) +
 558                   (Preds.idFor(BB)-1)] = cast<Constant>(Counter);
 559       }
 560     }
 561     Edge += Successors;
 562   }
 563
 564   ArrayRef<Constant*> V(&EdgeTable[0], Succs.size() * Preds.size());
 565   GlobalVariable *EdgeTableGV =
 566       new GlobalVariable(
 567           *M, EdgeTableTy, true, GlobalValue::InternalLinkage,
 568           ConstantArray::get(EdgeTableTy, V),
 569           "__llvm_gcda_edge_table");
 570   EdgeTableGV->setUnnamedAddr(true);
 571   return EdgeTableGV;
 572 }
 573
 574 Constant *GCOVProfiler::getStartFileFunc() {
 575   const Type *Args[] = { Type::getInt8PtrTy(*Ctx) };
 576   const FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx),
 577                                               Args, false);
 578   return M->getOrInsertFunction("llvm_gcda_start_file", FTy);
 579 }
 580
 581 Constant *GCOVProfiler::getIncrementIndirectCounterFunc() {
 582   const Type *Args[] = {
 583     Type::getInt32PtrTy(*Ctx),                  // uint32_t *predecessor
 584     Type::getInt64PtrTy(*Ctx)->getPointerTo(),  // uint64_t **state_table_row
 585   };
 586   const FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx),
 587                                               Args, false);
 588   return M->getOrInsertFunction("llvm_gcda_increment_indirect_counter", FTy);
 589 }
 590
 591 Constant *GCOVProfiler::getEmitFunctionFunc() {
 592   const Type *Args[2] = {
 593     Type::getInt32Ty(*Ctx),    // uint32_t ident
 594     Type::getInt8PtrTy(*Ctx),  // const char *function_name
 595   };
 596   const FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx),
 597                                               Args, false);
 598   return M->getOrInsertFunction("llvm_gcda_emit_function", FTy);
 599 }
 600
 601 Constant *GCOVProfiler::getEmitArcsFunc() {
 602   const Type *Args[] = {
 603     Type::getInt32Ty(*Ctx),     // uint32_t num_counters
 604     Type::getInt64PtrTy(*Ctx),  // uint64_t *counters
 605   };
 606   const FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx),
 607                                               Args, false);
 608   return M->getOrInsertFunction("llvm_gcda_emit_arcs", FTy);
 609 }
 610
 611 Constant *GCOVProfiler::getEndFileFunc() {
 612   const FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
 613   return M->getOrInsertFunction("llvm_gcda_end_file", FTy);
 614 }
 615
 616 GlobalVariable *GCOVProfiler::getEdgeStateValue() {
 617   GlobalVariable *GV = M->getGlobalVariable("__llvm_gcov_global_state_pred");
 618   if (!GV) {
 619     GV = new GlobalVariable(*M, Type::getInt32Ty(*Ctx), false,
 620                             GlobalValue::InternalLinkage,
 621                             ConstantInt::get(Type::getInt32Ty(*Ctx),
 622                                              0xffffffff),
 623                             "__llvm_gcov_global_state_pred");
 624     GV->setUnnamedAddr(true);
 625   }
 626   return GV;
 627 }
 628
 629 void GCOVProfiler::insertCounterWriteout(
 630     DebugInfoFinder &DIF,
 631     SmallVector<std::pair<GlobalVariable *, MDNode *>, 8> &CountersBySP) {
 632   const FunctionType *WriteoutFTy =
 633       FunctionType::get(Type::getVoidTy(*Ctx), false);
 634   Function *WriteoutF = Function::Create(WriteoutFTy,
 635                                          GlobalValue::InternalLinkage,
 636                                          "__llvm_gcov_writeout", M);
 637   WriteoutF->setUnnamedAddr(true);
 638   BasicBlock *BB = BasicBlock::Create(*Ctx, "", WriteoutF);
 639   IRBuilder<> Builder(BB);
 640
 641   Constant *StartFile = getStartFileFunc();
 642   Constant *EmitFunction = getEmitFunctionFunc();
 643   Constant *EmitArcs = getEmitArcsFunc();
 644   Constant *EndFile = getEndFileFunc();
 645
 646   for (DebugInfoFinder::iterator CUI = DIF.compile_unit_begin(),
 647            CUE = DIF.compile_unit_end(); CUI != CUE; ++CUI) {
 648     DICompileUnit compile_unit(*CUI);
 649     std::string FilenameGcda = mangleName(compile_unit, "gcda");
 650     Builder.CreateCall(StartFile,
 651                        Builder.CreateGlobalStringPtr(FilenameGcda));
 652     for (SmallVector<std::pair<GlobalVariable *, MDNode *>, 8>::iterator
 653              I = CountersBySP.begin(), E = CountersBySP.end();
 654          I != E; ++I) {
 655       DISubprogram SP(I->second);
 656       intptr_t ident = reinterpret_cast<intptr_t>(I->second);
 657       Builder.CreateCall2(EmitFunction,
 658                           ConstantInt::get(Type::getInt32Ty(*Ctx), ident),
 659                           Builder.CreateGlobalStringPtr(SP.getName()));
 660
 661       GlobalVariable *GV = I->first;
 662       unsigned Arcs =
 663           cast<ArrayType>(GV->getType()->getElementType())->getNumElements();
 664       Builder.CreateCall2(EmitArcs,
 665                           ConstantInt::get(Type::getInt32Ty(*Ctx), Arcs),
 666                           Builder.CreateConstGEP2_64(GV, 0, 0));
 667     }
 668     Builder.CreateCall(EndFile);
 669   }
 670   Builder.CreateRetVoid();
 671
 672   InsertProfilingShutdownCall(WriteoutF, M);
 673 }