GCOVProfiling.cpp revision 726f1b90a9e9149227a9aa37a2219f167776f804 
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>
39using namespace llvm;
40
41namespace {
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
104char GCOVProfiler::ID = 0;
105INITIALIZE_PASS(GCOVProfiler, "insert-gcov-profiling",
106                "Insert instrumentation for GCOV profiling", false, false)
107
108ModulePass *llvm::createGCOVProfilerPass(bool EmitNotes, bool EmitData,
109                                         bool Use402Format) {
110  return new GCOVProfiler(EmitNotes, EmitData, Use402Format);
111}
112
113static 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
122namespace {
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
331std::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
352bool 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
364void 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*204MVLL", 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
427bool 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    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, Idx);
482          Value *Count = Builder.CreateLoad(Counter);
483          Count = Builder.CreateAdd(Count,
484                                    ConstantInt::get(Type::getInt64Ty(*Ctx),1));
485          Builder.CreateStore(Count, Counter);
486        } else {
487          ComplexEdgePreds.insert(BB);
488          for (int i = 0; i != Successors; ++i)
489            ComplexEdgeSuccs.insert(TI->getSuccessor(i));
490        }
491        Edge += Successors;
492      }
493    }
494
495    if (!ComplexEdgePreds.empty()) {
496      GlobalVariable *EdgeTable =
497          buildEdgeLookupTable(F, Counters,
498                               ComplexEdgePreds, ComplexEdgeSuccs);
499      GlobalVariable *EdgeState = getEdgeStateValue();
500
501      Type *Int32Ty = Type::getInt32Ty(*Ctx);
502      for (int i = 0, e = ComplexEdgePreds.size(); i != e; ++i) {
503        IRBuilder<> Builder(ComplexEdgePreds[i+1]->getTerminator());
504        Builder.CreateStore(ConstantInt::get(Int32Ty, i), EdgeState);
505      }
506      for (int i = 0, e = ComplexEdgeSuccs.size(); i != e; ++i) {
507        // call runtime to perform increment
508        IRBuilder<> Builder(ComplexEdgeSuccs[i+1]->getFirstNonPHI());
509        Value *CounterPtrArray =
510            Builder.CreateConstInBoundsGEP2_64(EdgeTable, 0,
511                                               i * ComplexEdgePreds.size());
512        Builder.CreateCall2(getIncrementIndirectCounterFunc(),
513                            EdgeState, CounterPtrArray);
514        // clear the predecessor number
515        Builder.CreateStore(ConstantInt::get(Int32Ty, 0xffffffff), EdgeState);
516      }
517    }
518  }
519
520  insertCounterWriteout(DIF, CountersBySP);
521
522  return true;
523}
524
525// All edges with successors that aren't branches are "complex", because it
526// requires complex logic to pick which counter to update.
527GlobalVariable *GCOVProfiler::buildEdgeLookupTable(
528    Function *F,
529    GlobalVariable *Counters,
530    const UniqueVector<BasicBlock *> &Preds,
531    const UniqueVector<BasicBlock *> &Succs) {
532  // TODO: support invoke, threads. We rely on the fact that nothing can modify
533  // the whole-Module pred edge# between the time we set it and the time we next
534  // read it. Threads and invoke make this untrue.
535
536  // emit [(succs * preds) x i64*], logically [succ x [pred x i64*]].
537  Type *Int64PtrTy = Type::getInt64PtrTy(*Ctx);
538  ArrayType *EdgeTableTy = ArrayType::get(
539      Int64PtrTy, Succs.size() * Preds.size());
540
541  Constant **EdgeTable = new Constant*[Succs.size() * Preds.size()];
542  Constant *NullValue = Constant::getNullValue(Int64PtrTy);
543  for (int i = 0, ie = Succs.size() * Preds.size(); i != ie; ++i)
544    EdgeTable[i] = NullValue;
545
546  unsigned Edge = 0;
547  for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
548    TerminatorInst *TI = BB->getTerminator();
549    int Successors = isa<ReturnInst>(TI) ? 1 : TI->getNumSuccessors();
550    if (Successors > 1 && !isa<BranchInst>(TI) && !isa<ReturnInst>(TI)) {
551      for (int i = 0; i != Successors; ++i) {
552        BasicBlock *Succ = TI->getSuccessor(i);
553        IRBuilder<> builder(Succ);
554        Value *Counter = builder.CreateConstInBoundsGEP2_64(Counters, 0,
555                                                            Edge + i);
556        EdgeTable[((Succs.idFor(Succ)-1) * Preds.size()) +
557                  (Preds.idFor(BB)-1)] = cast<Constant>(Counter);
558      }
559    }
560    Edge += Successors;
561  }
562
563  ArrayRef<Constant*> V(&EdgeTable[0], Succs.size() * Preds.size());
564  GlobalVariable *EdgeTableGV =
565      new GlobalVariable(
566          *M, EdgeTableTy, true, GlobalValue::InternalLinkage,
567          ConstantArray::get(EdgeTableTy, V),
568          "__llvm_gcda_edge_table");
569  EdgeTableGV->setUnnamedAddr(true);
570  return EdgeTableGV;
571}
572
573Constant *GCOVProfiler::getStartFileFunc() {
574  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx),
575                                              Type::getInt8PtrTy(*Ctx), false);
576  return M->getOrInsertFunction("llvm_gcda_start_file", FTy);
577}
578
579Constant *GCOVProfiler::getIncrementIndirectCounterFunc() {
580  Type *Args[] = {
581    Type::getInt32PtrTy(*Ctx),                  // uint32_t *predecessor
582    Type::getInt64PtrTy(*Ctx)->getPointerTo(),  // uint64_t **state_table_row
583  };
584  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx),
585                                              Args, false);
586  return M->getOrInsertFunction("llvm_gcda_increment_indirect_counter", FTy);
587}
588
589Constant *GCOVProfiler::getEmitFunctionFunc() {
590  Type *Args[2] = {
591    Type::getInt32Ty(*Ctx),    // uint32_t ident
592    Type::getInt8PtrTy(*Ctx),  // const char *function_name
593  };
594  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx),
595                                              Args, false);
596  return M->getOrInsertFunction("llvm_gcda_emit_function", FTy);
597}
598
599Constant *GCOVProfiler::getEmitArcsFunc() {
600  Type *Args[] = {
601    Type::getInt32Ty(*Ctx),     // uint32_t num_counters
602    Type::getInt64PtrTy(*Ctx),  // uint64_t *counters
603  };
604  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx),
605                                              Args, false);
606  return M->getOrInsertFunction("llvm_gcda_emit_arcs", FTy);
607}
608
609Constant *GCOVProfiler::getEndFileFunc() {
610  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
611  return M->getOrInsertFunction("llvm_gcda_end_file", FTy);
612}
613
614GlobalVariable *GCOVProfiler::getEdgeStateValue() {
615  GlobalVariable *GV = M->getGlobalVariable("__llvm_gcov_global_state_pred");
616  if (!GV) {
617    GV = new GlobalVariable(*M, Type::getInt32Ty(*Ctx), false,
618                            GlobalValue::InternalLinkage,
619                            ConstantInt::get(Type::getInt32Ty(*Ctx),
620                                             0xffffffff),
621                            "__llvm_gcov_global_state_pred");
622    GV->setUnnamedAddr(true);
623  }
624  return GV;
625}
626
627void GCOVProfiler::insertCounterWriteout(
628    DebugInfoFinder &DIF,
629    SmallVector<std::pair<GlobalVariable *, MDNode *>, 8> &CountersBySP) {
630  FunctionType *WriteoutFTy =
631      FunctionType::get(Type::getVoidTy(*Ctx), false);
632  Function *WriteoutF = Function::Create(WriteoutFTy,
633                                         GlobalValue::InternalLinkage,
634                                         "__llvm_gcov_writeout", M);
635  WriteoutF->setUnnamedAddr(true);
636  BasicBlock *BB = BasicBlock::Create(*Ctx, "", WriteoutF);
637  IRBuilder<> Builder(BB);
638
639  Constant *StartFile = getStartFileFunc();
640  Constant *EmitFunction = getEmitFunctionFunc();
641  Constant *EmitArcs = getEmitArcsFunc();
642  Constant *EndFile = getEndFileFunc();
643
644  for (DebugInfoFinder::iterator CUI = DIF.compile_unit_begin(),
645           CUE = DIF.compile_unit_end(); CUI != CUE; ++CUI) {
646    DICompileUnit compile_unit(*CUI);
647    std::string FilenameGcda = mangleName(compile_unit, "gcda");
648    Builder.CreateCall(StartFile,
649                       Builder.CreateGlobalStringPtr(FilenameGcda));
650    for (SmallVector<std::pair<GlobalVariable *, MDNode *>, 8>::iterator
651             I = CountersBySP.begin(), E = CountersBySP.end();
652         I != E; ++I) {
653      DISubprogram SP(I->second);
654      intptr_t ident = reinterpret_cast<intptr_t>(I->second);
655      Builder.CreateCall2(EmitFunction,
656                          ConstantInt::get(Type::getInt32Ty(*Ctx), ident),
657                          Builder.CreateGlobalStringPtr(SP.getName()));
658
659      GlobalVariable *GV = I->first;
660      unsigned Arcs =
661          cast<ArrayType>(GV->getType()->getElementType())->getNumElements();
662      Builder.CreateCall2(EmitArcs,
663                          ConstantInt::get(Type::getInt32Ty(*Ctx), Arcs),
664                          Builder.CreateConstGEP2_64(GV, 0, 0));
665    }
666    Builder.CreateCall(EndFile);
667  }
668  Builder.CreateRetVoid();
669
670  InsertProfilingShutdownCall(WriteoutF, M);
671}
672