src/llvm/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/DebugInfo.h"
  22 #include "llvm/IRBuilder.h"
  23 #include "llvm/Instructions.h"
  24 #include "llvm/Module.h"
  25 #include "llvm/Pass.h"
  26 #include "llvm/ADT/DenseMap.h"
  27 #include "llvm/ADT/STLExtras.h"
  28 #include "llvm/ADT/Statistic.h"
  29 #include "llvm/ADT/StringExtras.h"
  30 #include "llvm/ADT/StringMap.h"
  31 #include "llvm/ADT/UniqueVector.h"
  32 #include "llvm/Support/Debug.h"
  33 #include "llvm/Support/DebugLoc.h"
  34 #include "llvm/Support/InstIterator.h"
  35 #include "llvm/Support/PathV2.h"
  36 #include "llvm/Support/raw_ostream.h"
  37 #include "llvm/Transforms/Utils/ModuleUtils.h"
  38 #include <string>
  39 #include <utility>
  40 using namespace llvm;
  41
  42 namespace {
  43   class GCOVProfiler : public ModulePass {
  44   public:
  45     static char ID;
  46     GCOVProfiler()
  47         : ModulePass(ID), EmitNotes(true), EmitData(true), Use402Format(false),
  48           UseExtraChecksum(false) {
  49       initializeGCOVProfilerPass(*PassRegistry::getPassRegistry());
  50     }
  51     GCOVProfiler(bool EmitNotes, bool EmitData, bool use402Format = false,
  52                  bool useExtraChecksum = false)
  53         : ModulePass(ID), EmitNotes(EmitNotes), EmitData(EmitData),
  54           Use402Format(use402Format), UseExtraChecksum(useExtraChecksum) {
  55       assert((EmitNotes || EmitData) && "GCOVProfiler asked to do nothing?");
  56       initializeGCOVProfilerPass(*PassRegistry::getPassRegistry());
  57     }
  58     virtual const char *getPassName() const {
  59       return "GCOV Profiler";
  60     }
  61   private:
  62     bool runOnModule(Module &M);
  63
  64     // Create the GCNO files for the Module based on DebugInfo.
  65     void emitGCNO();
  66
  67     // Modify the program to track transitions along edges and call into the
  68     // profiling runtime to emit .gcda files when run.
  69     bool emitProfileArcs();
  70
  71     // Get pointers to the functions in the runtime library.
  72     Constant *getStartFileFunc();
  73     Constant *getIncrementIndirectCounterFunc();
  74     Constant *getEmitFunctionFunc();
  75     Constant *getEmitArcsFunc();
  76     Constant *getEndFileFunc();
  77
  78     // Create or retrieve an i32 state value that is used to represent the
  79     // pred block number for certain non-trivial edges.
  80     GlobalVariable *getEdgeStateValue();
  81
  82     // Produce a table of pointers to counters, by predecessor and successor
  83     // block number.
  84     GlobalVariable *buildEdgeLookupTable(Function *F,
  85                                          GlobalVariable *Counter,
  86                                          const UniqueVector<BasicBlock *> &Preds,
  87                                          const UniqueVector<BasicBlock *> &Succs);
  88
  89     // Add the function to write out all our counters to the global destructor
  90     // list.
  91     void insertCounterWriteout(ArrayRef<std::pair<GlobalVariable*, MDNode*> >);
  92     void insertIndirectCounterIncrement();
  93     void insertFlush(ArrayRef<std::pair<GlobalVariable*, MDNode*> >);
  94
  95     std::string mangleName(DICompileUnit CU, const char *NewStem);
  96
  97     bool EmitNotes;
  98     bool EmitData;
  99     bool Use402Format;
 100     bool UseExtraChecksum;
 101
 102     Module *M;
 103     LLVMContext *Ctx;
 104   };
 105 }
 106
 107 char GCOVProfiler::ID = 0;
 108 INITIALIZE_PASS(GCOVProfiler, "insert-gcov-profiling",
 109                 "Insert instrumentation for GCOV profiling", false, false)
 110
 111 ModulePass *llvm::createGCOVProfilerPass(bool EmitNotes, bool EmitData,
 112                                          bool Use402Format,
 113                                          bool UseExtraChecksum) {
 114   return new GCOVProfiler(EmitNotes, EmitData, Use402Format, UseExtraChecksum);
 115 }
 116
 117 namespace {
 118   class GCOVRecord {
 119    protected:
 120     static const char *LinesTag;
 121     static const char *FunctionTag;
 122     static const char *BlockTag;
 123     static const char *EdgeTag;
 124
 125     GCOVRecord() {}
 126
 127     void writeBytes(const char *Bytes, int Size) {
 128       os->write(Bytes, Size);
 129     }
 130
 131     void write(uint32_t i) {
 132       writeBytes(reinterpret_cast<char*>(&i), 4);
 133     }
 134
 135     // Returns the length measured in 4-byte blocks that will be used to
 136     // represent this string in a GCOV file
 137     unsigned lengthOfGCOVString(StringRef s) {
 138       // A GCOV string is a length, followed by a NUL, then between 0 and 3 NULs
 139       // padding out to the next 4-byte word. The length is measured in 4-byte
 140       // words including padding, not bytes of actual string.
 141       return (s.size() / 4) + 1;
 142     }
 143
 144     void writeGCOVString(StringRef s) {
 145       uint32_t Len = lengthOfGCOVString(s);
 146       write(Len);
 147       writeBytes(s.data(), s.size());
 148
 149       // Write 1 to 4 bytes of NUL padding.
 150       assert((unsigned)(4 - (s.size() % 4)) > 0);
 151       assert((unsigned)(4 - (s.size() % 4)) <= 4);
 152       writeBytes("\0\0\0\0", 4 - (s.size() % 4));
 153     }
 154
 155     raw_ostream *os;
 156   };
 157   const char *GCOVRecord::LinesTag = "\0\0\x45\x01";
 158   const char *GCOVRecord::FunctionTag = "\0\0\0\1";
 159   const char *GCOVRecord::BlockTag = "\0\0\x41\x01";
 160   const char *GCOVRecord::EdgeTag = "\0\0\x43\x01";
 161
 162   class GCOVFunction;
 163   class GCOVBlock;
 164
 165   // Constructed only by requesting it from a GCOVBlock, this object stores a
 166   // list of line numbers and a single filename, representing lines that belong
 167   // to the block.
 168   class GCOVLines : public GCOVRecord {
 169    public:
 170     void addLine(uint32_t Line) {
 171       Lines.push_back(Line);
 172     }
 173
 174     uint32_t length() {
 175       // Here 2 = 1 for string length + 1 for '0' id#.
 176       return lengthOfGCOVString(Filename) + 2 + Lines.size();
 177     }
 178
 179     void writeOut() {
 180       write(0);
 181       writeGCOVString(Filename);
 182       for (int i = 0, e = Lines.size(); i != e; ++i)
 183         write(Lines[i]);
 184     }
 185
 186     GCOVLines(StringRef F, raw_ostream *os)
 187       : Filename(F) {
 188       this->os = os;
 189     }
 190
 191    private:
 192     StringRef Filename;
 193     SmallVector<uint32_t, 32> Lines;
 194   };
 195
 196   // Represent a basic block in GCOV. Each block has a unique number in the
 197   // function, number of lines belonging to each block, and a set of edges to
 198   // other blocks.
 199   class GCOVBlock : public GCOVRecord {
 200    public:
 201     GCOVLines &getFile(StringRef Filename) {
 202       GCOVLines *&Lines = LinesByFile[Filename];
 203       if (!Lines) {
 204         Lines = new GCOVLines(Filename, os);
 205       }
 206       return *Lines;
 207     }
 208
 209     void addEdge(GCOVBlock &Successor) {
 210       OutEdges.push_back(&Successor);
 211     }
 212
 213     void writeOut() {
 214       uint32_t Len = 3;
 215       for (StringMap<GCOVLines *>::iterator I = LinesByFile.begin(),
 216                E = LinesByFile.end(); I != E; ++I) {
 217         Len += I->second->length();
 218       }
 219
 220       writeBytes(LinesTag, 4);
 221       write(Len);
 222       write(Number);
 223       for (StringMap<GCOVLines *>::iterator I = LinesByFile.begin(),
 224                E = LinesByFile.end(); I != E; ++I)
 225         I->second->writeOut();
 226       write(0);
 227       write(0);
 228     }
 229
 230     ~GCOVBlock() {
 231       DeleteContainerSeconds(LinesByFile);
 232     }
 233
 234    private:
 235     friend class GCOVFunction;
 236
 237     GCOVBlock(uint32_t Number, raw_ostream *os)
 238         : Number(Number) {
 239       this->os = os;
 240     }
 241
 242     uint32_t Number;
 243     StringMap<GCOVLines *> LinesByFile;
 244     SmallVector<GCOVBlock *, 4> OutEdges;
 245   };
 246
 247   // A function has a unique identifier, a checksum (we leave as zero) and a
 248   // set of blocks and a map of edges between blocks. This is the only GCOV
 249   // object users can construct, the blocks and lines will be rooted here.
 250   class GCOVFunction : public GCOVRecord {
 251    public:
 252     GCOVFunction(DISubprogram SP, raw_ostream *os,
 253                  bool Use402Format, bool UseExtraChecksum) {
 254       this->os = os;
 255
 256       Function *F = SP.getFunction();
 257       DEBUG(dbgs() << "Function: " << F->getName() << "\n");
 258       uint32_t i = 0;
 259       for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
 260         Blocks[BB] = new GCOVBlock(i++, os);
 261       }
 262       ReturnBlock = new GCOVBlock(i++, os);
 263
 264       writeBytes(FunctionTag, 4);
 265       uint32_t BlockLen = 1 + 1 + 1 + lengthOfGCOVString(SP.getName()) +
 266           1 + lengthOfGCOVString(SP.getFilename()) + 1;
 267       if (UseExtraChecksum)
 268         ++BlockLen;
 269       write(BlockLen);
 270       uint32_t Ident = reinterpret_cast<intptr_t>((MDNode*)SP);
 271       write(Ident);
 272       write(0);  // lineno checksum
 273       if (UseExtraChecksum)
 274         write(0);  // cfg checksum
 275       writeGCOVString(SP.getName());
 276       writeGCOVString(SP.getFilename());
 277       write(SP.getLineNumber());
 278     }
 279
 280     ~GCOVFunction() {
 281       DeleteContainerSeconds(Blocks);
 282       delete ReturnBlock;
 283     }
 284
 285     GCOVBlock &getBlock(BasicBlock *BB) {
 286       return *Blocks[BB];
 287     }
 288
 289     GCOVBlock &getReturnBlock() {
 290       return *ReturnBlock;
 291     }
 292
 293     void writeOut() {
 294       // Emit count of blocks.
 295       writeBytes(BlockTag, 4);
 296       write(Blocks.size() + 1);
 297       for (int i = 0, e = Blocks.size() + 1; i != e; ++i) {
 298         write(0);  // No flags on our blocks.
 299       }
 300       DEBUG(dbgs() << Blocks.size() << " blocks.\n");
 301
 302       // Emit edges between blocks.
 303       for (DenseMap<BasicBlock *, GCOVBlock *>::iterator I = Blocks.begin(),
 304                E = Blocks.end(); I != E; ++I) {
 305         GCOVBlock &Block = *I->second;
 306         if (Block.OutEdges.empty()) continue;
 307
 308         writeBytes(EdgeTag, 4);
 309         write(Block.OutEdges.size() * 2 + 1);
 310         write(Block.Number);
 311         for (int i = 0, e = Block.OutEdges.size(); i != e; ++i) {
 312           DEBUG(dbgs() << Block.Number << " -> " << Block.OutEdges[i]->Number
 313                        << "\n");
 314           write(Block.OutEdges[i]->Number);
 315           write(0);  // no flags
 316         }
 317       }
 318
 319       // Emit lines for each block.
 320       for (DenseMap<BasicBlock *, GCOVBlock *>::iterator I = Blocks.begin(),
 321                E = Blocks.end(); I != E; ++I) {
 322         I->second->writeOut();
 323       }
 324     }
 325
 326    private:
 327     DenseMap<BasicBlock *, GCOVBlock *> Blocks;
 328     GCOVBlock *ReturnBlock;
 329   };
 330 }
 331
 332 std::string GCOVProfiler::mangleName(DICompileUnit CU, const char *NewStem) {
 333   if (NamedMDNode *GCov = M->getNamedMetadata("llvm.gcov")) {
 334     for (int i = 0, e = GCov->getNumOperands(); i != e; ++i) {
 335       MDNode *N = GCov->getOperand(i);
 336       if (N->getNumOperands() != 2) continue;
 337       MDString *GCovFile = dyn_cast<MDString>(N->getOperand(0));
 338       MDNode *CompileUnit = dyn_cast<MDNode>(N->getOperand(1));
 339       if (!GCovFile || !CompileUnit) continue;
 340       if (CompileUnit == CU) {
 341         SmallString<128> Filename = GCovFile->getString();
 342         sys::path::replace_extension(Filename, NewStem);
 343         return Filename.str();
 344       }
 345     }
 346   }
 347
 348   SmallString<128> Filename = CU.getFilename();
 349   sys::path::replace_extension(Filename, NewStem);
 350   return sys::path::filename(Filename.str());
 351 }
 352
 353 bool GCOVProfiler::runOnModule(Module &M) {
 354   this->M = &M;
 355   Ctx = &M.getContext();
 356
 357   if (EmitNotes) emitGCNO();
 358   if (EmitData) return emitProfileArcs();
 359   return false;
 360 }
 361
 362 void GCOVProfiler::emitGCNO() {
 363   NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
 364   if (!CU_Nodes) return;
 365
 366   for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
 367     // Each compile unit gets its own .gcno file. This means that whether we run
 368     // this pass over the original .o's as they're produced, or run it after
 369     // LTO, we'll generate the same .gcno files.
 370
 371     DICompileUnit CU(CU_Nodes->getOperand(i));
 372     std::string ErrorInfo;
 373     raw_fd_ostream out(mangleName(CU, "gcno").c_str(), ErrorInfo,
 374                        raw_fd_ostream::F_Binary);
 375     if (!Use402Format)
 376       out.write("oncg*404MVLL", 12);
 377     else
 378       out.write("oncg*204MVLL", 12);
 379
 380     DIArray SPs = CU.getSubprograms();
 381     for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i) {
 382       DISubprogram SP(SPs.getElement(i));
 383       if (!SP.Verify()) continue;
 384
 385       Function *F = SP.getFunction();
 386       if (!F) continue;
 387       GCOVFunction Func(SP, &out, Use402Format, UseExtraChecksum);
 388
 389       for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
 390         GCOVBlock &Block = Func.getBlock(BB);
 391         TerminatorInst *TI = BB->getTerminator();
 392         if (int successors = TI->getNumSuccessors()) {
 393           for (int i = 0; i != successors; ++i) {
 394             Block.addEdge(Func.getBlock(TI->getSuccessor(i)));
 395           }
 396         } else if (isa<ReturnInst>(TI)) {
 397           Block.addEdge(Func.getReturnBlock());
 398         }
 399
 400         uint32_t Line = 0;
 401         for (BasicBlock::iterator I = BB->begin(), IE = BB->end();
 402              I != IE; ++I) {
 403           const DebugLoc &Loc = I->getDebugLoc();
 404           if (Loc.isUnknown()) continue;
 405           if (Line == Loc.getLine()) continue;
 406           Line = Loc.getLine();
 407           if (SP != getDISubprogram(Loc.getScope(*Ctx))) continue;
 408
 409           GCOVLines &Lines = Block.getFile(SP.getFilename());
 410           Lines.addLine(Loc.getLine());
 411         }
 412       }
 413       Func.writeOut();
 414     }
 415     out.write("\0\0\0\0\0\0\0\0", 8);  // EOF
 416     out.close();
 417   }
 418 }
 419
 420 bool GCOVProfiler::emitProfileArcs() {
 421   NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
 422   if (!CU_Nodes) return false;
 423
 424   bool Result = false;
 425   bool InsertIndCounterIncrCode = false;
 426   for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
 427     DICompileUnit CU(CU_Nodes->getOperand(i));
 428     DIArray SPs = CU.getSubprograms();
 429     SmallVector<std::pair<GlobalVariable *, MDNode *>, 8> CountersBySP;
 430     for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i) {
 431       DISubprogram SP(SPs.getElement(i));
 432       if (!SP.Verify()) continue;
 433       Function *F = SP.getFunction();
 434       if (!F) continue;
 435       if (!Result) Result = true;
 436       unsigned Edges = 0;
 437       for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
 438         TerminatorInst *TI = BB->getTerminator();
 439         if (isa<ReturnInst>(TI))
 440           ++Edges;
 441         else
 442           Edges += TI->getNumSuccessors();
 443       }
 444
 445       ArrayType *CounterTy =
 446         ArrayType::get(Type::getInt64Ty(*Ctx), Edges);
 447       GlobalVariable *Counters =
 448         new GlobalVariable(*M, CounterTy, false,
 449                            GlobalValue::InternalLinkage,
 450                            Constant::getNullValue(CounterTy),
 451                            "__llvm_gcov_ctr");
 452       CountersBySP.push_back(std::make_pair(Counters, (MDNode*)SP));
 453
 454       UniqueVector<BasicBlock *> ComplexEdgePreds;
 455       UniqueVector<BasicBlock *> ComplexEdgeSuccs;
 456
 457       unsigned Edge = 0;
 458       for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
 459         TerminatorInst *TI = BB->getTerminator();
 460         int Successors = isa<ReturnInst>(TI) ? 1 : TI->getNumSuccessors();
 461         if (Successors) {
 462           IRBuilder<> Builder(TI);
 463
 464           if (Successors == 1) {
 465             Value *Counter = Builder.CreateConstInBoundsGEP2_64(Counters, 0,
 466                                                                 Edge);
 467             Value *Count = Builder.CreateLoad(Counter);
 468             Count = Builder.CreateAdd(Count,
 469                                       ConstantInt::get(Type::getInt64Ty(*Ctx),1));
 470             Builder.CreateStore(Count, Counter);
 471           } else if (BranchInst *BI = dyn_cast<BranchInst>(TI)) {
 472             Value *Sel = Builder.CreateSelect(
 473               BI->getCondition(),
 474               ConstantInt::get(Type::getInt64Ty(*Ctx), Edge),
 475               ConstantInt::get(Type::getInt64Ty(*Ctx), Edge + 1));
 476             SmallVector<Value *, 2> Idx;
 477             Idx.push_back(Constant::getNullValue(Type::getInt64Ty(*Ctx)));
 478             Idx.push_back(Sel);
 479             Value *Counter = Builder.CreateInBoundsGEP(Counters, Idx);
 480             Value *Count = Builder.CreateLoad(Counter);
 481             Count = Builder.CreateAdd(Count,
 482                                       ConstantInt::get(Type::getInt64Ty(*Ctx),1));
 483             Builder.CreateStore(Count, Counter);
 484           } else {
 485             ComplexEdgePreds.insert(BB);
 486             for (int i = 0; i != Successors; ++i)
 487               ComplexEdgeSuccs.insert(TI->getSuccessor(i));
 488           }
 489           Edge += Successors;
 490         }
 491       }
 492
 493       if (!ComplexEdgePreds.empty()) {
 494         GlobalVariable *EdgeTable =
 495           buildEdgeLookupTable(F, Counters,
 496                                ComplexEdgePreds, ComplexEdgeSuccs);
 497         GlobalVariable *EdgeState = getEdgeStateValue();
 498
 499         Type *Int32Ty = Type::getInt32Ty(*Ctx);
 500         for (int i = 0, e = ComplexEdgePreds.size(); i != e; ++i) {
 501           IRBuilder<> Builder(ComplexEdgePreds[i+1]->getTerminator());
 502           Builder.CreateStore(ConstantInt::get(Int32Ty, i), EdgeState);
 503         }
 504         for (int i = 0, e = ComplexEdgeSuccs.size(); i != e; ++i) {
 505           // call runtime to perform increment
 506           BasicBlock::iterator InsertPt =
 507             ComplexEdgeSuccs[i+1]->getFirstInsertionPt();
 508           IRBuilder<> Builder(InsertPt);
 509           Value *CounterPtrArray =
 510             Builder.CreateConstInBoundsGEP2_64(EdgeTable, 0,
 511                                                i * ComplexEdgePreds.size());
 512
 513           // Build code to increment the counter.
 514           InsertIndCounterIncrCode = true;
 515           Builder.CreateCall2(getIncrementIndirectCounterFunc(),
 516                               EdgeState, CounterPtrArray);
 517         }
 518       }
 519     }
 520
 521     insertCounterWriteout(CountersBySP);
 522     insertFlush(CountersBySP);
 523   }
 524
 525   if (InsertIndCounterIncrCode)
 526     insertIndirectCounterIncrement();
 527
 528   return Result;
 529 }
 530
 531 // All edges with successors that aren't branches are "complex", because it
 532 // requires complex logic to pick which counter to update.
 533 GlobalVariable *GCOVProfiler::buildEdgeLookupTable(
 534     Function *F,
 535     GlobalVariable *Counters,
 536     const UniqueVector<BasicBlock *> &Preds,
 537     const UniqueVector<BasicBlock *> &Succs) {
 538   // TODO: support invoke, threads. We rely on the fact that nothing can modify
 539   // the whole-Module pred edge# between the time we set it and the time we next
 540   // read it. Threads and invoke make this untrue.
 541
 542   // emit [(succs * preds) x i64*], logically [succ x [pred x i64*]].
 543   Type *Int64PtrTy = Type::getInt64PtrTy(*Ctx);
 544   ArrayType *EdgeTableTy = ArrayType::get(
 545       Int64PtrTy, Succs.size() * Preds.size());
 546
 547   Constant **EdgeTable = new Constant*[Succs.size() * Preds.size()];
 548   Constant *NullValue = Constant::getNullValue(Int64PtrTy);
 549   for (int i = 0, ie = Succs.size() * Preds.size(); i != ie; ++i)
 550     EdgeTable[i] = NullValue;
 551
 552   unsigned Edge = 0;
 553   for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
 554     TerminatorInst *TI = BB->getTerminator();
 555     int Successors = isa<ReturnInst>(TI) ? 1 : TI->getNumSuccessors();
 556     if (Successors > 1 && !isa<BranchInst>(TI) && !isa<ReturnInst>(TI)) {
 557       for (int i = 0; i != Successors; ++i) {
 558         BasicBlock *Succ = TI->getSuccessor(i);
 559         IRBuilder<> builder(Succ);
 560         Value *Counter = builder.CreateConstInBoundsGEP2_64(Counters, 0,
 561                                                             Edge + i);
 562         EdgeTable[((Succs.idFor(Succ)-1) * Preds.size()) +
 563                   (Preds.idFor(BB)-1)] = cast<Constant>(Counter);
 564       }
 565     }
 566     Edge += Successors;
 567   }
 568
 569   ArrayRef<Constant*> V(&EdgeTable[0], Succs.size() * Preds.size());
 570   GlobalVariable *EdgeTableGV =
 571       new GlobalVariable(
 572           *M, EdgeTableTy, true, GlobalValue::InternalLinkage,
 573           ConstantArray::get(EdgeTableTy, V),
 574           "__llvm_gcda_edge_table");
 575   EdgeTableGV->setUnnamedAddr(true);
 576   return EdgeTableGV;
 577 }
 578
 579 Constant *GCOVProfiler::getStartFileFunc() {
 580   FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx),
 581                                               Type::getInt8PtrTy(*Ctx), false);
 582   return M->getOrInsertFunction("llvm_gcda_start_file", FTy);
 583 }
 584
 585 Constant *GCOVProfiler::getIncrementIndirectCounterFunc() {
 586   Type *Int32Ty = Type::getInt32Ty(*Ctx);
 587   Type *Int64Ty = Type::getInt64Ty(*Ctx);
 588   Type *Args[] = {
 589     Int32Ty->getPointerTo(),                // uint32_t *predecessor
 590     Int64Ty->getPointerTo()->getPointerTo() // uint64_t **counters
 591   };
 592   FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false);
 593   return M->getOrInsertFunction("__llvm_gcov_indirect_counter_increment", FTy);
 594 }
 595
 596 Constant *GCOVProfiler::getEmitFunctionFunc() {
 597   Type *Args[2] = {
 598     Type::getInt32Ty(*Ctx),    // uint32_t ident
 599     Type::getInt8PtrTy(*Ctx),  // const char *function_name
 600   };
 601   FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false);
 602   return M->getOrInsertFunction("llvm_gcda_emit_function", FTy);
 603 }
 604
 605 Constant *GCOVProfiler::getEmitArcsFunc() {
 606   Type *Args[] = {
 607     Type::getInt32Ty(*Ctx),     // uint32_t num_counters
 608     Type::getInt64PtrTy(*Ctx),  // uint64_t *counters
 609   };
 610   FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx),
 611                                               Args, false);
 612   return M->getOrInsertFunction("llvm_gcda_emit_arcs", FTy);
 613 }
 614
 615 Constant *GCOVProfiler::getEndFileFunc() {
 616   FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
 617   return M->getOrInsertFunction("llvm_gcda_end_file", FTy);
 618 }
 619
 620 GlobalVariable *GCOVProfiler::getEdgeStateValue() {
 621   GlobalVariable *GV = M->getGlobalVariable("__llvm_gcov_global_state_pred");
 622   if (!GV) {
 623     GV = new GlobalVariable(*M, Type::getInt32Ty(*Ctx), false,
 624                             GlobalValue::InternalLinkage,
 625                             ConstantInt::get(Type::getInt32Ty(*Ctx),
 626                                              0xffffffff),
 627                             "__llvm_gcov_global_state_pred");
 628     GV->setUnnamedAddr(true);
 629   }
 630   return GV;
 631 }
 632
 633 void GCOVProfiler::insertCounterWriteout(
 634     ArrayRef<std::pair<GlobalVariable *, MDNode *> > CountersBySP) {
 635   FunctionType *WriteoutFTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
 636   Function *WriteoutF = M->getFunction("__llvm_gcov_writeout");
 637   if (!WriteoutF)
 638     WriteoutF = Function::Create(WriteoutFTy, GlobalValue::InternalLinkage,
 639                                  "__llvm_gcov_writeout", M);
 640   WriteoutF->setUnnamedAddr(true);
 641
 642   BasicBlock *BB = BasicBlock::Create(*Ctx, "entry", WriteoutF);
 643   IRBuilder<> Builder(BB);
 644
 645   Constant *StartFile = getStartFileFunc();
 646   Constant *EmitFunction = getEmitFunctionFunc();
 647   Constant *EmitArcs = getEmitArcsFunc();
 648   Constant *EndFile = getEndFileFunc();
 649
 650   NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
 651   if (CU_Nodes) {
 652     for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
 653       DICompileUnit CU(CU_Nodes->getOperand(i));
 654       std::string FilenameGcda = mangleName(CU, "gcda");
 655       Builder.CreateCall(StartFile,
 656                          Builder.CreateGlobalStringPtr(FilenameGcda));
 657       for (ArrayRef<std::pair<GlobalVariable *, MDNode *> >::iterator
 658              I = CountersBySP.begin(), E = CountersBySP.end();
 659            I != E; ++I) {
 660         DISubprogram SP(I->second);
 661         intptr_t ident = reinterpret_cast<intptr_t>(I->second);
 662         Builder.CreateCall2(EmitFunction,
 663                             ConstantInt::get(Type::getInt32Ty(*Ctx), ident),
 664                             Builder.CreateGlobalStringPtr(SP.getName()));
 665
 666         GlobalVariable *GV = I->first;
 667         unsigned Arcs =
 668           cast<ArrayType>(GV->getType()->getElementType())->getNumElements();
 669         Builder.CreateCall2(EmitArcs,
 670                             ConstantInt::get(Type::getInt32Ty(*Ctx), Arcs),
 671                             Builder.CreateConstGEP2_64(GV, 0, 0));
 672       }
 673       Builder.CreateCall(EndFile);
 674     }
 675   }
 676   Builder.CreateRetVoid();
 677
 678   // Create a small bit of code that registers the "__llvm_gcov_writeout"
 679   // function to be executed at exit.
 680   FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
 681   Function *F = Function::Create(FTy, GlobalValue::InternalLinkage,
 682                                  "__llvm_gcov_init", M);
 683   F->setUnnamedAddr(true);
 684   F->setLinkage(GlobalValue::InternalLinkage);
 685   F->addFnAttr(Attribute::NoInline);
 686
 687   BB = BasicBlock::Create(*Ctx, "entry", F);
 688   Builder.SetInsertPoint(BB);
 689
 690   FTy = FunctionType::get(Type::getInt32Ty(*Ctx),
 691                           PointerType::get(FTy, 0), false);
 692   Constant *AtExitFn = M->getOrInsertFunction("atexit", FTy);
 693   Builder.CreateCall(AtExitFn, WriteoutF);
 694   Builder.CreateRetVoid();
 695
 696   appendToGlobalCtors(*M, F, 0);
 697 }
 698
 699 void GCOVProfiler::insertIndirectCounterIncrement() {
 700   Function *Fn =
 701     cast<Function>(GCOVProfiler::getIncrementIndirectCounterFunc());
 702   Fn->setUnnamedAddr(true);
 703   Fn->setLinkage(GlobalValue::InternalLinkage);
 704   Fn->addFnAttr(Attribute::NoInline);
 705
 706   Type *Int32Ty = Type::getInt32Ty(*Ctx);
 707   Type *Int64Ty = Type::getInt64Ty(*Ctx);
 708   Constant *NegOne = ConstantInt::get(Int32Ty, 0xffffffff);
 709
 710   // Create basic blocks for function.
 711   BasicBlock *BB = BasicBlock::Create(*Ctx, "entry", Fn);
 712   IRBuilder<> Builder(BB);
 713
 714   BasicBlock *PredNotNegOne = BasicBlock::Create(*Ctx, "", Fn);
 715   BasicBlock *CounterEnd = BasicBlock::Create(*Ctx, "", Fn);
 716   BasicBlock *Exit = BasicBlock::Create(*Ctx, "exit", Fn);
 717
 718   // uint32_t pred = *predecessor;
 719   // if (pred == 0xffffffff) return;
 720   Argument *Arg = Fn->arg_begin();
 721   Arg->setName("predecessor");
 722   Value *Pred = Builder.CreateLoad(Arg, "pred");
 723   Value *Cond = Builder.CreateICmpEQ(Pred, NegOne);
 724   BranchInst::Create(Exit, PredNotNegOne, Cond, BB);
 725
 726   Builder.SetInsertPoint(PredNotNegOne);
 727
 728   // uint64_t *counter = counters[pred];
 729   // if (!counter) return;
 730   Value *ZExtPred = Builder.CreateZExt(Pred, Int64Ty);
 731   Arg = llvm::next(Fn->arg_begin());
 732   Arg->setName("counters");
 733   Value *GEP = Builder.CreateGEP(Arg, ZExtPred);
 734   Value *Counter = Builder.CreateLoad(GEP, "counter");
 735   Cond = Builder.CreateICmpEQ(Counter,
 736                               Constant::getNullValue(Int64Ty->getPointerTo()));
 737   Builder.CreateCondBr(Cond, Exit, CounterEnd);
 738
 739   // ++*counter;
 740   Builder.SetInsertPoint(CounterEnd);
 741   Value *Add = Builder.CreateAdd(Builder.CreateLoad(Counter),
 742                                  ConstantInt::get(Int64Ty, 1));
 743   Builder.CreateStore(Add, Counter);
 744   Builder.CreateBr(Exit);
 745
 746   // Fill in the exit block.
 747   Builder.SetInsertPoint(Exit);
 748   Builder.CreateRetVoid();
 749 }
 750
 751 void GCOVProfiler::
 752 insertFlush(ArrayRef<std::pair<GlobalVariable*, MDNode*> > CountersBySP) {
 753   FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
 754   Function *FlushF = M->getFunction("__gcov_flush");
 755   if (!FlushF)
 756     FlushF = Function::Create(FTy, GlobalValue::InternalLinkage,
 757                               "__gcov_flush", M);
 758   else
 759     FlushF->setLinkage(GlobalValue::InternalLinkage);
 760   FlushF->setUnnamedAddr(true);
 761
 762   BasicBlock *Entry = BasicBlock::Create(*Ctx, "entry", FlushF);
 763
 764   // Write out the current counters.
 765   Constant *WriteoutF = M->getFunction("__llvm_gcov_writeout");
 766   assert(WriteoutF && "Need to create the writeout function first!");
 767
 768   IRBuilder<> Builder(Entry);
 769   Builder.CreateCall(WriteoutF);
 770
 771   // Zero out the counters.
 772   for (ArrayRef<std::pair<GlobalVariable *, MDNode *> >::iterator
 773          I = CountersBySP.begin(), E = CountersBySP.end();
 774        I != E; ++I) {
 775     GlobalVariable *GV = I->first;
 776     Constant *Null = Constant::getNullValue(GV->getType()->getElementType());
 777     Builder.CreateStore(Null, GV);
 778   }
 779
 780   Type *RetTy = FlushF->getReturnType();
 781   if (RetTy == Type::getVoidTy(*Ctx))
 782     Builder.CreateRetVoid();
 783   else if (RetTy->isIntegerTy())
 784     // Used if __gcov_flush was implicitly declared.
 785     Builder.CreateRet(ConstantInt::get(RetTy, 0));
 786   else
 787     report_fatal_error("invalid return type for __gcov_flush");
 788 }