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