GCOVProfiling.cpp revision 234353 
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          UseExtraChecksum(false) {
48      initializeGCOVProfilerPass(*PassRegistry::getPassRegistry());
49    }
50    GCOVProfiler(bool EmitNotes, bool EmitData, bool use402Format = false,
51                 bool useExtraChecksum = false)
52        : ModulePass(ID), EmitNotes(EmitNotes), EmitData(EmitData),
53          Use402Format(use402Format), UseExtraChecksum(useExtraChecksum) {
54      assert((EmitNotes || EmitData) && "GCOVProfiler asked to do nothing?");
55      initializeGCOVProfilerPass(*PassRegistry::getPassRegistry());
56    }
57    virtual const char *getPassName() const {
58      return "GCOV Profiler";
59    }
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(SmallVector<std::pair<GlobalVariable *,
92                                                     MDNode *>, 8> &);
93
94    std::string mangleName(DICompileUnit CU, std::string NewStem);
95
96    bool EmitNotes;
97    bool EmitData;
98    bool Use402Format;
99    bool UseExtraChecksum;
100
101    Module *M;
102    LLVMContext *Ctx;
103  };
104}
105
106char GCOVProfiler::ID = 0;
107INITIALIZE_PASS(GCOVProfiler, "insert-gcov-profiling",
108                "Insert instrumentation for GCOV profiling", false, false)
109
110ModulePass *llvm::createGCOVProfilerPass(bool EmitNotes, bool EmitData,
111                                         bool Use402Format,
112                                         bool UseExtraChecksum) {
113  return new GCOVProfiler(EmitNotes, EmitData, Use402Format, UseExtraChecksum);
114}
115
116namespace {
117  class GCOVRecord {
118   protected:
119    static const char *LinesTag;
120    static const char *FunctionTag;
121    static const char *BlockTag;
122    static const char *EdgeTag;
123
124    GCOVRecord() {}
125
126    void writeBytes(const char *Bytes, int Size) {
127      os->write(Bytes, Size);
128    }
129
130    void write(uint32_t i) {
131      writeBytes(reinterpret_cast<char*>(&i), 4);
132    }
133
134    // Returns the length measured in 4-byte blocks that will be used to
135    // represent this string in a GCOV file
136    unsigned lengthOfGCOVString(StringRef s) {
137      // A GCOV string is a length, followed by a NUL, then between 0 and 3 NULs
138      // padding out to the next 4-byte word. The length is measured in 4-byte
139      // words including padding, not bytes of actual string.
140      return (s.size() / 4) + 1;
141    }
142
143    void writeGCOVString(StringRef s) {
144      uint32_t Len = lengthOfGCOVString(s);
145      write(Len);
146      writeBytes(s.data(), s.size());
147
148      // Write 1 to 4 bytes of NUL padding.
149      assert((unsigned)(4 - (s.size() % 4)) > 0);
150      assert((unsigned)(4 - (s.size() % 4)) <= 4);
151      writeBytes("\0\0\0\0", 4 - (s.size() % 4));
152    }
153
154    raw_ostream *os;
155  };
156  const char *GCOVRecord::LinesTag = "\0\0\x45\x01";
157  const char *GCOVRecord::FunctionTag = "\0\0\0\1";
158  const char *GCOVRecord::BlockTag = "\0\0\x41\x01";
159  const char *GCOVRecord::EdgeTag = "\0\0\x43\x01";
160
161  class GCOVFunction;
162  class GCOVBlock;
163
164  // Constructed only by requesting it from a GCOVBlock, this object stores a
165  // list of line numbers and a single filename, representing lines that belong
166  // to the block.
167  class GCOVLines : public GCOVRecord {
168   public:
169    void addLine(uint32_t Line) {
170      Lines.push_back(Line);
171    }
172
173    uint32_t length() {
174      // Here 2 = 1 for string length + 1 for '0' id#.
175      return lengthOfGCOVString(Filename) + 2 + Lines.size();
176    }
177
178    void writeOut() {
179      write(0);
180      writeGCOVString(Filename);
181      for (int i = 0, e = Lines.size(); i != e; ++i)
182        write(Lines[i]);
183    }
184
185    GCOVLines(StringRef F, raw_ostream *os)
186      : Filename(F) {
187      this->os = os;
188    }
189
190   private:
191    StringRef 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(StringRef 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        I->second->writeOut();
225      write(0);
226      write(0);
227    }
228
229    ~GCOVBlock() {
230      DeleteContainerSeconds(LinesByFile);
231    }
232
233   private:
234    friend class GCOVFunction;
235
236    GCOVBlock(uint32_t Number, raw_ostream *os)
237        : Number(Number) {
238      this->os = os;
239    }
240
241    uint32_t Number;
242    StringMap<GCOVLines *> LinesByFile;
243    SmallVector<GCOVBlock *, 4> OutEdges;
244  };
245
246  // A function has a unique identifier, a checksum (we leave as zero) and a
247  // set of blocks and a map of edges between blocks. This is the only GCOV
248  // object users can construct, the blocks and lines will be rooted here.
249  class GCOVFunction : public GCOVRecord {
250   public:
251    GCOVFunction(DISubprogram SP, raw_ostream *os,
252                 bool Use402Format, bool UseExtraChecksum) {
253      this->os = os;
254
255      Function *F = SP.getFunction();
256      DEBUG(dbgs() << "Function: " << F->getName() << "\n");
257      uint32_t i = 0;
258      for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
259        Blocks[BB] = new GCOVBlock(i++, os);
260      }
261      ReturnBlock = new GCOVBlock(i++, os);
262
263      writeBytes(FunctionTag, 4);
264      uint32_t BlockLen = 1 + 1 + 1 + lengthOfGCOVString(SP.getName()) +
265          1 + lengthOfGCOVString(SP.getFilename()) + 1;
266      if (UseExtraChecksum)
267        ++BlockLen;
268      write(BlockLen);
269      uint32_t Ident = reinterpret_cast<intptr_t>((MDNode*)SP);
270      write(Ident);
271      write(0);  // lineno checksum
272      if (UseExtraChecksum)
273        write(0);  // cfg checksum
274      writeGCOVString(SP.getName());
275      writeGCOVString(SP.getFilename());
276      write(SP.getLineNumber());
277    }
278
279    ~GCOVFunction() {
280      DeleteContainerSeconds(Blocks);
281      delete ReturnBlock;
282    }
283
284    GCOVBlock &getBlock(BasicBlock *BB) {
285      return *Blocks[BB];
286    }
287
288    GCOVBlock &getReturnBlock() {
289      return *ReturnBlock;
290    }
291
292    void writeOut() {
293      // Emit count of blocks.
294      writeBytes(BlockTag, 4);
295      write(Blocks.size() + 1);
296      for (int i = 0, e = Blocks.size() + 1; i != e; ++i) {
297        write(0);  // No flags on our blocks.
298      }
299      DEBUG(dbgs() << Blocks.size() << " blocks.\n");
300
301      // Emit edges between blocks.
302      for (DenseMap<BasicBlock *, GCOVBlock *>::iterator I = Blocks.begin(),
303               E = Blocks.end(); I != E; ++I) {
304        GCOVBlock &Block = *I->second;
305        if (Block.OutEdges.empty()) continue;
306
307        writeBytes(EdgeTag, 4);
308        write(Block.OutEdges.size() * 2 + 1);
309        write(Block.Number);
310        for (int i = 0, e = Block.OutEdges.size(); i != e; ++i) {
311          DEBUG(dbgs() << Block.Number << " -> " << Block.OutEdges[i]->Number
312                       << "\n");
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  if (EmitNotes) emitGCNO();
357  if (EmitData) return emitProfileArcs();
358  return false;
359}
360
361void GCOVProfiler::emitGCNO() {
362  NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
363  if (!CU_Nodes) return;
364
365  for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
366    // Each compile unit gets its own .gcno file. This means that whether we run
367    // this pass over the original .o's as they're produced, or run it after
368    // LTO, we'll generate the same .gcno files.
369
370    DICompileUnit CU(CU_Nodes->getOperand(i));
371    std::string ErrorInfo;
372    raw_fd_ostream out(mangleName(CU, "gcno").c_str(), ErrorInfo,
373                       raw_fd_ostream::F_Binary);
374    if (!Use402Format)
375      out.write("oncg*404MVLL", 12);
376    else
377      out.write("oncg*204MVLL", 12);
378
379    DIArray SPs = CU.getSubprograms();
380    for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i) {
381      DISubprogram SP(SPs.getElement(i));
382      if (!SP.Verify()) continue;
383
384      Function *F = SP.getFunction();
385      if (!F) continue;
386      GCOVFunction Func(SP, &out, Use402Format, UseExtraChecksum);
387
388      for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
389        GCOVBlock &Block = Func.getBlock(BB);
390        TerminatorInst *TI = BB->getTerminator();
391        if (int successors = TI->getNumSuccessors()) {
392          for (int i = 0; i != successors; ++i) {
393            Block.addEdge(Func.getBlock(TI->getSuccessor(i)));
394          }
395        } else if (isa<ReturnInst>(TI)) {
396          Block.addEdge(Func.getReturnBlock());
397        }
398
399        uint32_t Line = 0;
400        for (BasicBlock::iterator I = BB->begin(), IE = BB->end();
401             I != IE; ++I) {
402          const DebugLoc &Loc = I->getDebugLoc();
403          if (Loc.isUnknown()) continue;
404          if (Line == Loc.getLine()) continue;
405          Line = Loc.getLine();
406          if (SP != getDISubprogram(Loc.getScope(*Ctx))) continue;
407
408          GCOVLines &Lines = Block.getFile(SP.getFilename());
409          Lines.addLine(Loc.getLine());
410        }
411      }
412      Func.writeOut();
413    }
414    out.write("\0\0\0\0\0\0\0\0", 8);  // EOF
415    out.close();
416  }
417}
418
419bool GCOVProfiler::emitProfileArcs() {
420  NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
421  if (!CU_Nodes) return false;
422
423  bool Result = false;
424  for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
425    DICompileUnit CU(CU_Nodes->getOperand(i));
426    DIArray SPs = CU.getSubprograms();
427    SmallVector<std::pair<GlobalVariable *, MDNode *>, 8> CountersBySP;
428    for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i) {
429      DISubprogram SP(SPs.getElement(i));
430      if (!SP.Verify()) continue;
431      Function *F = SP.getFunction();
432      if (!F) continue;
433      if (!Result) Result = true;
434      unsigned Edges = 0;
435      for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
436        TerminatorInst *TI = BB->getTerminator();
437        if (isa<ReturnInst>(TI))
438          ++Edges;
439        else
440          Edges += TI->getNumSuccessors();
441      }
442
443      ArrayType *CounterTy =
444        ArrayType::get(Type::getInt64Ty(*Ctx), Edges);
445      GlobalVariable *Counters =
446        new GlobalVariable(*M, CounterTy, false,
447                           GlobalValue::InternalLinkage,
448                           Constant::getNullValue(CounterTy),
449                           "__llvm_gcov_ctr", 0, false, 0);
450      CountersBySP.push_back(std::make_pair(Counters, (MDNode*)SP));
451
452      UniqueVector<BasicBlock *> ComplexEdgePreds;
453      UniqueVector<BasicBlock *> ComplexEdgeSuccs;
454
455      unsigned Edge = 0;
456      for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
457        TerminatorInst *TI = BB->getTerminator();
458        int Successors = isa<ReturnInst>(TI) ? 1 : TI->getNumSuccessors();
459        if (Successors) {
460          IRBuilder<> Builder(TI);
461
462          if (Successors == 1) {
463            Value *Counter = Builder.CreateConstInBoundsGEP2_64(Counters, 0,
464                                                                Edge);
465            Value *Count = Builder.CreateLoad(Counter);
466            Count = Builder.CreateAdd(Count,
467                                      ConstantInt::get(Type::getInt64Ty(*Ctx),1));
468            Builder.CreateStore(Count, Counter);
469          } else if (BranchInst *BI = dyn_cast<BranchInst>(TI)) {
470            Value *Sel = Builder.CreateSelect(
471              BI->getCondition(),
472              ConstantInt::get(Type::getInt64Ty(*Ctx), Edge),
473              ConstantInt::get(Type::getInt64Ty(*Ctx), Edge + 1));
474            SmallVector<Value *, 2> Idx;
475            Idx.push_back(Constant::getNullValue(Type::getInt64Ty(*Ctx)));
476            Idx.push_back(Sel);
477            Value *Counter = Builder.CreateInBoundsGEP(Counters, Idx);
478            Value *Count = Builder.CreateLoad(Counter);
479            Count = Builder.CreateAdd(Count,
480                                      ConstantInt::get(Type::getInt64Ty(*Ctx),1));
481            Builder.CreateStore(Count, Counter);
482          } else {
483            ComplexEdgePreds.insert(BB);
484            for (int i = 0; i != Successors; ++i)
485              ComplexEdgeSuccs.insert(TI->getSuccessor(i));
486          }
487          Edge += Successors;
488        }
489      }
490
491      if (!ComplexEdgePreds.empty()) {
492        GlobalVariable *EdgeTable =
493          buildEdgeLookupTable(F, Counters,
494                               ComplexEdgePreds, ComplexEdgeSuccs);
495        GlobalVariable *EdgeState = getEdgeStateValue();
496
497        Type *Int32Ty = Type::getInt32Ty(*Ctx);
498        for (int i = 0, e = ComplexEdgePreds.size(); i != e; ++i) {
499          IRBuilder<> Builder(ComplexEdgePreds[i+1]->getTerminator());
500          Builder.CreateStore(ConstantInt::get(Int32Ty, i), EdgeState);
501        }
502        for (int i = 0, e = ComplexEdgeSuccs.size(); i != e; ++i) {
503          // call runtime to perform increment
504          BasicBlock::iterator InsertPt =
505            ComplexEdgeSuccs[i+1]->getFirstInsertionPt();
506          IRBuilder<> Builder(InsertPt);
507          Value *CounterPtrArray =
508            Builder.CreateConstInBoundsGEP2_64(EdgeTable, 0,
509                                               i * ComplexEdgePreds.size());
510          Builder.CreateCall2(getIncrementIndirectCounterFunc(),
511                              EdgeState, CounterPtrArray);
512          // clear the predecessor number
513          Builder.CreateStore(ConstantInt::get(Int32Ty, 0xffffffff), EdgeState);
514        }
515      }
516    }
517    insertCounterWriteout(CountersBySP);
518  }
519  return Result;
520}
521
522// All edges with successors that aren't branches are "complex", because it
523// requires complex logic to pick which counter to update.
524GlobalVariable *GCOVProfiler::buildEdgeLookupTable(
525    Function *F,
526    GlobalVariable *Counters,
527    const UniqueVector<BasicBlock *> &Preds,
528    const UniqueVector<BasicBlock *> &Succs) {
529  // TODO: support invoke, threads. We rely on the fact that nothing can modify
530  // the whole-Module pred edge# between the time we set it and the time we next
531  // read it. Threads and invoke make this untrue.
532
533  // emit [(succs * preds) x i64*], logically [succ x [pred x i64*]].
534  Type *Int64PtrTy = Type::getInt64PtrTy(*Ctx);
535  ArrayType *EdgeTableTy = ArrayType::get(
536      Int64PtrTy, Succs.size() * Preds.size());
537
538  Constant **EdgeTable = new Constant*[Succs.size() * Preds.size()];
539  Constant *NullValue = Constant::getNullValue(Int64PtrTy);
540  for (int i = 0, ie = Succs.size() * Preds.size(); i != ie; ++i)
541    EdgeTable[i] = NullValue;
542
543  unsigned Edge = 0;
544  for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
545    TerminatorInst *TI = BB->getTerminator();
546    int Successors = isa<ReturnInst>(TI) ? 1 : TI->getNumSuccessors();
547    if (Successors > 1 && !isa<BranchInst>(TI) && !isa<ReturnInst>(TI)) {
548      for (int i = 0; i != Successors; ++i) {
549        BasicBlock *Succ = TI->getSuccessor(i);
550        IRBuilder<> builder(Succ);
551        Value *Counter = builder.CreateConstInBoundsGEP2_64(Counters, 0,
552                                                            Edge + i);
553        EdgeTable[((Succs.idFor(Succ)-1) * Preds.size()) +
554                  (Preds.idFor(BB)-1)] = cast<Constant>(Counter);
555      }
556    }
557    Edge += Successors;
558  }
559
560  ArrayRef<Constant*> V(&EdgeTable[0], Succs.size() * Preds.size());
561  GlobalVariable *EdgeTableGV =
562      new GlobalVariable(
563          *M, EdgeTableTy, true, GlobalValue::InternalLinkage,
564          ConstantArray::get(EdgeTableTy, V),
565          "__llvm_gcda_edge_table");
566  EdgeTableGV->setUnnamedAddr(true);
567  return EdgeTableGV;
568}
569
570Constant *GCOVProfiler::getStartFileFunc() {
571  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx),
572                                              Type::getInt8PtrTy(*Ctx), false);
573  return M->getOrInsertFunction("llvm_gcda_start_file", FTy);
574}
575
576Constant *GCOVProfiler::getIncrementIndirectCounterFunc() {
577  Type *Args[] = {
578    Type::getInt32PtrTy(*Ctx),                  // uint32_t *predecessor
579    Type::getInt64PtrTy(*Ctx)->getPointerTo(),  // uint64_t **state_table_row
580  };
581  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx),
582                                              Args, false);
583  return M->getOrInsertFunction("llvm_gcda_increment_indirect_counter", FTy);
584}
585
586Constant *GCOVProfiler::getEmitFunctionFunc() {
587  Type *Args[2] = {
588    Type::getInt32Ty(*Ctx),    // uint32_t ident
589    Type::getInt8PtrTy(*Ctx),  // const char *function_name
590  };
591  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx),
592                                              Args, false);
593  return M->getOrInsertFunction("llvm_gcda_emit_function", FTy);
594}
595
596Constant *GCOVProfiler::getEmitArcsFunc() {
597  Type *Args[] = {
598    Type::getInt32Ty(*Ctx),     // uint32_t num_counters
599    Type::getInt64PtrTy(*Ctx),  // uint64_t *counters
600  };
601  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx),
602                                              Args, false);
603  return M->getOrInsertFunction("llvm_gcda_emit_arcs", FTy);
604}
605
606Constant *GCOVProfiler::getEndFileFunc() {
607  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
608  return M->getOrInsertFunction("llvm_gcda_end_file", FTy);
609}
610
611GlobalVariable *GCOVProfiler::getEdgeStateValue() {
612  GlobalVariable *GV = M->getGlobalVariable("__llvm_gcov_global_state_pred");
613  if (!GV) {
614    GV = new GlobalVariable(*M, Type::getInt32Ty(*Ctx), false,
615                            GlobalValue::InternalLinkage,
616                            ConstantInt::get(Type::getInt32Ty(*Ctx),
617                                             0xffffffff),
618                            "__llvm_gcov_global_state_pred");
619    GV->setUnnamedAddr(true);
620  }
621  return GV;
622}
623
624void GCOVProfiler::insertCounterWriteout(
625    SmallVector<std::pair<GlobalVariable *, MDNode *>, 8> &CountersBySP) {
626  FunctionType *WriteoutFTy =
627      FunctionType::get(Type::getVoidTy(*Ctx), false);
628  Function *WriteoutF = Function::Create(WriteoutFTy,
629                                         GlobalValue::InternalLinkage,
630                                         "__llvm_gcov_writeout", M);
631  WriteoutF->setUnnamedAddr(true);
632  BasicBlock *BB = BasicBlock::Create(*Ctx, "", WriteoutF);
633  IRBuilder<> Builder(BB);
634
635  Constant *StartFile = getStartFileFunc();
636  Constant *EmitFunction = getEmitFunctionFunc();
637  Constant *EmitArcs = getEmitArcsFunc();
638  Constant *EndFile = getEndFileFunc();
639
640  NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
641  if (CU_Nodes) {
642    for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
643      DICompileUnit compile_unit(CU_Nodes->getOperand(i));
644      std::string FilenameGcda = mangleName(compile_unit, "gcda");
645      Builder.CreateCall(StartFile,
646                         Builder.CreateGlobalStringPtr(FilenameGcda));
647      for (SmallVector<std::pair<GlobalVariable *, MDNode *>, 8>::iterator
648             I = CountersBySP.begin(), E = CountersBySP.end();
649           I != E; ++I) {
650        DISubprogram SP(I->second);
651        intptr_t ident = reinterpret_cast<intptr_t>(I->second);
652        Builder.CreateCall2(EmitFunction,
653                            ConstantInt::get(Type::getInt32Ty(*Ctx), ident),
654                            Builder.CreateGlobalStringPtr(SP.getName()));
655
656        GlobalVariable *GV = I->first;
657        unsigned Arcs =
658          cast<ArrayType>(GV->getType()->getElementType())->getNumElements();
659        Builder.CreateCall2(EmitArcs,
660                            ConstantInt::get(Type::getInt32Ty(*Ctx), Arcs),
661                            Builder.CreateConstGEP2_64(GV, 0, 0));
662      }
663      Builder.CreateCall(EndFile);
664    }
665  }
666  Builder.CreateRetVoid();
667
668  InsertProfilingShutdownCall(WriteoutF, M);
669}
670