GCOVProfiling.cpp revision d9686a98b8145010516c44a3a5b9b96bf934b9ac 
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 "llvm/Transforms/Instrumentation.h"
20#include "ProfilingUtils.h"
21#include "llvm/ADT/DenseMap.h"
22#include "llvm/ADT/STLExtras.h"
23#include "llvm/ADT/Statistic.h"
24#include "llvm/ADT/StringExtras.h"
25#include "llvm/ADT/StringMap.h"
26#include "llvm/ADT/UniqueVector.h"
27#include "llvm/DebugInfo.h"
28#include "llvm/IR/IRBuilder.h"
29#include "llvm/IR/Instructions.h"
30#include "llvm/IR/Module.h"
31#include "llvm/Pass.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>
40using namespace llvm;
41
42namespace {
43  class GCOVProfiler : public ModulePass {
44  public:
45    static char ID;
46    GCOVProfiler()
47        : ModulePass(ID), EmitNotes(true), EmitData(true),
48          UseExtraChecksum(false), NoRedZone(false),
49          NoFunctionNamesInData(false) {
50      memcpy(Version, DefaultGCovVersion, 4);
51      initializeGCOVProfilerPass(*PassRegistry::getPassRegistry());
52    }
53    GCOVProfiler(bool EmitNotes, bool EmitData, const char (&Version)[4],
54                 bool UseExtraChecksum, bool NoRedZone,
55                 bool NoFunctionNamesInData)
56        : ModulePass(ID), EmitNotes(EmitNotes), EmitData(EmitData),
57          UseExtraChecksum(UseExtraChecksum), NoRedZone(NoRedZone),
58          NoFunctionNamesInData(NoFunctionNamesInData) {
59      memcpy(this->Version, Version, 4);
60      assert((EmitNotes || EmitData) && "GCOVProfiler asked to do nothing?");
61      initializeGCOVProfilerPass(*PassRegistry::getPassRegistry());
62    }
63    virtual const char *getPassName() const {
64      return "GCOV Profiler";
65    }
66  private:
67    bool runOnModule(Module &M);
68
69    // Create the GCNO files for the Module based on DebugInfo.
70    void emitGCNO();
71
72    // Modify the program to track transitions along edges and call into the
73    // profiling runtime to emit .gcda files when run.
74    bool emitProfileArcs();
75
76    // Get pointers to the functions in the runtime library.
77    Constant *getStartFileFunc();
78    Constant *getIncrementIndirectCounterFunc();
79    Constant *getEmitFunctionFunc();
80    Constant *getEmitArcsFunc();
81    Constant *getEndFileFunc();
82
83    // Create or retrieve an i32 state value that is used to represent the
84    // pred block number for certain non-trivial edges.
85    GlobalVariable *getEdgeStateValue();
86
87    // Produce a table of pointers to counters, by predecessor and successor
88    // block number.
89    GlobalVariable *buildEdgeLookupTable(Function *F,
90                                         GlobalVariable *Counter,
91                                         const UniqueVector<BasicBlock *> &Preds,
92                                         const UniqueVector<BasicBlock *> &Succs);
93
94    // Add the function to write out all our counters to the global destructor
95    // list.
96    void insertCounterWriteout(ArrayRef<std::pair<GlobalVariable*, MDNode*> >);
97    void insertIndirectCounterIncrement();
98    void insertFlush(ArrayRef<std::pair<GlobalVariable*, MDNode*> >);
99
100    std::string mangleName(DICompileUnit CU, const char *NewStem);
101
102    bool EmitNotes;
103    bool EmitData;
104    char Version[4];
105    bool UseExtraChecksum;
106    bool NoRedZone;
107    bool NoFunctionNamesInData;
108
109    Module *M;
110    LLVMContext *Ctx;
111  };
112}
113
114char GCOVProfiler::ID = 0;
115INITIALIZE_PASS(GCOVProfiler, "insert-gcov-profiling",
116                "Insert instrumentation for GCOV profiling", false, false)
117
118ModulePass *llvm::createGCOVProfilerPass(bool EmitNotes, bool EmitData,
119                                         const char (&Version)[4],
120                                         bool UseExtraChecksum,
121                                         bool NoRedZone,
122                                         bool NoFunctionNamesInData) {
123  return new GCOVProfiler(EmitNotes, EmitData, Version, UseExtraChecksum,
124                          NoRedZone, NoFunctionNamesInData);
125}
126
127namespace {
128  class GCOVRecord {
129   protected:
130    static const char *LinesTag;
131    static const char *FunctionTag;
132    static const char *BlockTag;
133    static const char *EdgeTag;
134
135    GCOVRecord() {}
136
137    void writeBytes(const char *Bytes, int Size) {
138      os->write(Bytes, Size);
139    }
140
141    void write(uint32_t i) {
142      writeBytes(reinterpret_cast<char*>(&i), 4);
143    }
144
145    // Returns the length measured in 4-byte blocks that will be used to
146    // represent this string in a GCOV file
147    unsigned lengthOfGCOVString(StringRef s) {
148      // A GCOV string is a length, followed by a NUL, then between 0 and 3 NULs
149      // padding out to the next 4-byte word. The length is measured in 4-byte
150      // words including padding, not bytes of actual string.
151      return (s.size() / 4) + 1;
152    }
153
154    void writeGCOVString(StringRef s) {
155      uint32_t Len = lengthOfGCOVString(s);
156      write(Len);
157      writeBytes(s.data(), s.size());
158
159      // Write 1 to 4 bytes of NUL padding.
160      assert((unsigned)(4 - (s.size() % 4)) > 0);
161      assert((unsigned)(4 - (s.size() % 4)) <= 4);
162      writeBytes("\0\0\0\0", 4 - (s.size() % 4));
163    }
164
165    raw_ostream *os;
166  };
167  const char *GCOVRecord::LinesTag = "\0\0\x45\x01";
168  const char *GCOVRecord::FunctionTag = "\0\0\0\1";
169  const char *GCOVRecord::BlockTag = "\0\0\x41\x01";
170  const char *GCOVRecord::EdgeTag = "\0\0\x43\x01";
171
172  class GCOVFunction;
173  class GCOVBlock;
174
175  // Constructed only by requesting it from a GCOVBlock, this object stores a
176  // list of line numbers and a single filename, representing lines that belong
177  // to the block.
178  class GCOVLines : public GCOVRecord {
179   public:
180    void addLine(uint32_t Line) {
181      Lines.push_back(Line);
182    }
183
184    uint32_t length() {
185      // Here 2 = 1 for string length + 1 for '0' id#.
186      return lengthOfGCOVString(Filename) + 2 + Lines.size();
187    }
188
189    void writeOut() {
190      write(0);
191      writeGCOVString(Filename);
192      for (int i = 0, e = Lines.size(); i != e; ++i)
193        write(Lines[i]);
194    }
195
196    GCOVLines(StringRef F, raw_ostream *os)
197      : Filename(F) {
198      this->os = os;
199    }
200
201   private:
202    StringRef Filename;
203    SmallVector<uint32_t, 32> Lines;
204  };
205
206  // Represent a basic block in GCOV. Each block has a unique number in the
207  // function, number of lines belonging to each block, and a set of edges to
208  // other blocks.
209  class GCOVBlock : public GCOVRecord {
210   public:
211    GCOVLines &getFile(StringRef Filename) {
212      GCOVLines *&Lines = LinesByFile[Filename];
213      if (!Lines) {
214        Lines = new GCOVLines(Filename, os);
215      }
216      return *Lines;
217    }
218
219    void addEdge(GCOVBlock &Successor) {
220      OutEdges.push_back(&Successor);
221    }
222
223    void writeOut() {
224      uint32_t Len = 3;
225      for (StringMap<GCOVLines *>::iterator I = LinesByFile.begin(),
226               E = LinesByFile.end(); I != E; ++I) {
227        Len += I->second->length();
228      }
229
230      writeBytes(LinesTag, 4);
231      write(Len);
232      write(Number);
233      for (StringMap<GCOVLines *>::iterator I = LinesByFile.begin(),
234               E = LinesByFile.end(); I != E; ++I)
235        I->second->writeOut();
236      write(0);
237      write(0);
238    }
239
240    ~GCOVBlock() {
241      DeleteContainerSeconds(LinesByFile);
242    }
243
244   private:
245    friend class GCOVFunction;
246
247    GCOVBlock(uint32_t Number, raw_ostream *os)
248        : Number(Number) {
249      this->os = os;
250    }
251
252    uint32_t Number;
253    StringMap<GCOVLines *> LinesByFile;
254    SmallVector<GCOVBlock *, 4> OutEdges;
255  };
256
257  // A function has a unique identifier, a checksum (we leave as zero) and a
258  // set of blocks and a map of edges between blocks. This is the only GCOV
259  // object users can construct, the blocks and lines will be rooted here.
260  class GCOVFunction : public GCOVRecord {
261   public:
262    GCOVFunction(DISubprogram SP, raw_ostream *os, uint32_t Ident,
263                 bool UseExtraChecksum) {
264      this->os = os;
265
266      Function *F = SP.getFunction();
267      DEBUG(dbgs() << "Function: " << F->getName() << "\n");
268      uint32_t i = 0;
269      for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
270        Blocks[BB] = new GCOVBlock(i++, os);
271      }
272      ReturnBlock = new GCOVBlock(i++, os);
273
274      writeBytes(FunctionTag, 4);
275      uint32_t BlockLen = 1 + 1 + 1 + lengthOfGCOVString(SP.getName()) +
276          1 + lengthOfGCOVString(SP.getFilename()) + 1;
277      if (UseExtraChecksum)
278        ++BlockLen;
279      write(BlockLen);
280      write(Ident);
281      write(0);  // lineno checksum
282      if (UseExtraChecksum)
283        write(0);  // cfg checksum
284      writeGCOVString(SP.getName());
285      writeGCOVString(SP.getFilename());
286      write(SP.getLineNumber());
287    }
288
289    ~GCOVFunction() {
290      DeleteContainerSeconds(Blocks);
291      delete ReturnBlock;
292    }
293
294    GCOVBlock &getBlock(BasicBlock *BB) {
295      return *Blocks[BB];
296    }
297
298    GCOVBlock &getReturnBlock() {
299      return *ReturnBlock;
300    }
301
302    void writeOut() {
303      // Emit count of blocks.
304      writeBytes(BlockTag, 4);
305      write(Blocks.size() + 1);
306      for (int i = 0, e = Blocks.size() + 1; i != e; ++i) {
307        write(0);  // No flags on our blocks.
308      }
309      DEBUG(dbgs() << Blocks.size() << " blocks.\n");
310
311      // Emit edges between blocks.
312      for (DenseMap<BasicBlock *, GCOVBlock *>::iterator I = Blocks.begin(),
313               E = Blocks.end(); I != E; ++I) {
314        GCOVBlock &Block = *I->second;
315        if (Block.OutEdges.empty()) continue;
316
317        writeBytes(EdgeTag, 4);
318        write(Block.OutEdges.size() * 2 + 1);
319        write(Block.Number);
320        for (int i = 0, e = Block.OutEdges.size(); i != e; ++i) {
321          DEBUG(dbgs() << Block.Number << " -> " << Block.OutEdges[i]->Number
322                       << "\n");
323          write(Block.OutEdges[i]->Number);
324          write(0);  // no flags
325        }
326      }
327
328      // Emit lines for each block.
329      for (DenseMap<BasicBlock *, GCOVBlock *>::iterator I = Blocks.begin(),
330               E = Blocks.end(); I != E; ++I) {
331        I->second->writeOut();
332      }
333    }
334
335   private:
336    DenseMap<BasicBlock *, GCOVBlock *> Blocks;
337    GCOVBlock *ReturnBlock;
338  };
339}
340
341std::string GCOVProfiler::mangleName(DICompileUnit CU, const char *NewStem) {
342  if (NamedMDNode *GCov = M->getNamedMetadata("llvm.gcov")) {
343    for (int i = 0, e = GCov->getNumOperands(); i != e; ++i) {
344      MDNode *N = GCov->getOperand(i);
345      if (N->getNumOperands() != 2) continue;
346      MDString *GCovFile = dyn_cast<MDString>(N->getOperand(0));
347      MDNode *CompileUnit = dyn_cast<MDNode>(N->getOperand(1));
348      if (!GCovFile || !CompileUnit) continue;
349      if (CompileUnit == CU) {
350        SmallString<128> Filename = GCovFile->getString();
351        sys::path::replace_extension(Filename, NewStem);
352        return Filename.str();
353      }
354    }
355  }
356
357  SmallString<128> Filename = CU.getFilename();
358  sys::path::replace_extension(Filename, NewStem);
359  return sys::path::filename(Filename.str());
360}
361
362bool GCOVProfiler::runOnModule(Module &M) {
363  this->M = &M;
364  Ctx = &M.getContext();
365
366  if (EmitNotes) emitGCNO();
367  if (EmitData) return emitProfileArcs();
368  return false;
369}
370
371void GCOVProfiler::emitGCNO() {
372  NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
373  if (!CU_Nodes) return;
374
375  for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
376    // Each compile unit gets its own .gcno file. This means that whether we run
377    // this pass over the original .o's as they're produced, or run it after
378    // LTO, we'll generate the same .gcno files.
379
380    DICompileUnit CU(CU_Nodes->getOperand(i));
381    std::string ErrorInfo;
382    raw_fd_ostream out(mangleName(CU, "gcno").c_str(), ErrorInfo,
383                       raw_fd_ostream::F_Binary);
384    out.write("oncg", 4);
385    out.write(Version, 4);
386    out.write("MVLL", 4);
387
388    DIArray SPs = CU.getSubprograms();
389    for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i) {
390      DISubprogram SP(SPs.getElement(i));
391      if (!SP.Verify()) continue;
392
393      Function *F = SP.getFunction();
394      if (!F) continue;
395      GCOVFunction Func(SP, &out, i, UseExtraChecksum);
396
397      for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
398        GCOVBlock &Block = Func.getBlock(BB);
399        TerminatorInst *TI = BB->getTerminator();
400        if (int successors = TI->getNumSuccessors()) {
401          for (int i = 0; i != successors; ++i) {
402            Block.addEdge(Func.getBlock(TI->getSuccessor(i)));
403          }
404        } else if (isa<ReturnInst>(TI)) {
405          Block.addEdge(Func.getReturnBlock());
406        }
407
408        uint32_t Line = 0;
409        for (BasicBlock::iterator I = BB->begin(), IE = BB->end();
410             I != IE; ++I) {
411          const DebugLoc &Loc = I->getDebugLoc();
412          if (Loc.isUnknown()) continue;
413          if (Line == Loc.getLine()) continue;
414          Line = Loc.getLine();
415          if (SP != getDISubprogram(Loc.getScope(*Ctx))) continue;
416
417          GCOVLines &Lines = Block.getFile(SP.getFilename());
418          Lines.addLine(Loc.getLine());
419        }
420      }
421      Func.writeOut();
422    }
423    out.write("\0\0\0\0\0\0\0\0", 8);  // EOF
424    out.close();
425  }
426}
427
428bool GCOVProfiler::emitProfileArcs() {
429  NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
430  if (!CU_Nodes) return false;
431
432  bool Result = false;
433  bool InsertIndCounterIncrCode = false;
434  for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
435    DICompileUnit CU(CU_Nodes->getOperand(i));
436    DIArray SPs = CU.getSubprograms();
437    SmallVector<std::pair<GlobalVariable *, MDNode *>, 8> CountersBySP;
438    for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i) {
439      DISubprogram SP(SPs.getElement(i));
440      if (!SP.Verify()) continue;
441      Function *F = SP.getFunction();
442      if (!F) continue;
443      if (!Result) Result = true;
444      unsigned Edges = 0;
445      for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
446        TerminatorInst *TI = BB->getTerminator();
447        if (isa<ReturnInst>(TI))
448          ++Edges;
449        else
450          Edges += TI->getNumSuccessors();
451      }
452
453      ArrayType *CounterTy =
454        ArrayType::get(Type::getInt64Ty(*Ctx), Edges);
455      GlobalVariable *Counters =
456        new GlobalVariable(*M, CounterTy, false,
457                           GlobalValue::InternalLinkage,
458                           Constant::getNullValue(CounterTy),
459                           "__llvm_gcov_ctr");
460      CountersBySP.push_back(std::make_pair(Counters, (MDNode*)SP));
461
462      UniqueVector<BasicBlock *> ComplexEdgePreds;
463      UniqueVector<BasicBlock *> ComplexEdgeSuccs;
464
465      unsigned Edge = 0;
466      for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
467        TerminatorInst *TI = BB->getTerminator();
468        int Successors = isa<ReturnInst>(TI) ? 1 : TI->getNumSuccessors();
469        if (Successors) {
470          IRBuilder<> Builder(TI);
471
472          if (Successors == 1) {
473            Value *Counter = Builder.CreateConstInBoundsGEP2_64(Counters, 0,
474                                                                Edge);
475            Value *Count = Builder.CreateLoad(Counter);
476            Count = Builder.CreateAdd(Count, Builder.getInt64(1));
477            Builder.CreateStore(Count, Counter);
478          } else if (BranchInst *BI = dyn_cast<BranchInst>(TI)) {
479            Value *Sel = Builder.CreateSelect(BI->getCondition(),
480                                              Builder.getInt64(Edge),
481                                              Builder.getInt64(Edge + 1));
482            SmallVector<Value *, 2> Idx;
483            Idx.push_back(Builder.getInt64(0));
484            Idx.push_back(Sel);
485            Value *Counter = Builder.CreateInBoundsGEP(Counters, Idx);
486            Value *Count = Builder.CreateLoad(Counter);
487            Count = Builder.CreateAdd(Count, Builder.getInt64(1));
488            Builder.CreateStore(Count, Counter);
489          } else {
490            ComplexEdgePreds.insert(BB);
491            for (int i = 0; i != Successors; ++i)
492              ComplexEdgeSuccs.insert(TI->getSuccessor(i));
493          }
494          Edge += Successors;
495        }
496      }
497
498      if (!ComplexEdgePreds.empty()) {
499        GlobalVariable *EdgeTable =
500          buildEdgeLookupTable(F, Counters,
501                               ComplexEdgePreds, ComplexEdgeSuccs);
502        GlobalVariable *EdgeState = getEdgeStateValue();
503
504        for (int i = 0, e = ComplexEdgePreds.size(); i != e; ++i) {
505          IRBuilder<> Builder(ComplexEdgePreds[i+1]->getTerminator());
506          Builder.CreateStore(Builder.getInt32(i), EdgeState);
507        }
508        for (int i = 0, e = ComplexEdgeSuccs.size(); i != e; ++i) {
509          // call runtime to perform increment
510          BasicBlock::iterator InsertPt =
511            ComplexEdgeSuccs[i+1]->getFirstInsertionPt();
512          IRBuilder<> Builder(InsertPt);
513          Value *CounterPtrArray =
514            Builder.CreateConstInBoundsGEP2_64(EdgeTable, 0,
515                                               i * ComplexEdgePreds.size());
516
517          // Build code to increment the counter.
518          InsertIndCounterIncrCode = true;
519          Builder.CreateCall2(getIncrementIndirectCounterFunc(),
520                              EdgeState, CounterPtrArray);
521        }
522      }
523    }
524
525    insertCounterWriteout(CountersBySP);
526    insertFlush(CountersBySP);
527  }
528
529  if (InsertIndCounterIncrCode)
530    insertIndirectCounterIncrement();
531
532  return Result;
533}
534
535// All edges with successors that aren't branches are "complex", because it
536// requires complex logic to pick which counter to update.
537GlobalVariable *GCOVProfiler::buildEdgeLookupTable(
538    Function *F,
539    GlobalVariable *Counters,
540    const UniqueVector<BasicBlock *> &Preds,
541    const UniqueVector<BasicBlock *> &Succs) {
542  // TODO: support invoke, threads. We rely on the fact that nothing can modify
543  // the whole-Module pred edge# between the time we set it and the time we next
544  // read it. Threads and invoke make this untrue.
545
546  // emit [(succs * preds) x i64*], logically [succ x [pred x i64*]].
547  size_t TableSize = Succs.size() * Preds.size();
548  Type *Int64PtrTy = Type::getInt64PtrTy(*Ctx);
549  ArrayType *EdgeTableTy = ArrayType::get(Int64PtrTy, TableSize);
550
551  OwningArrayPtr<Constant *> EdgeTable(new Constant*[TableSize]);
552  Constant *NullValue = Constant::getNullValue(Int64PtrTy);
553  for (size_t i = 0; i != TableSize; ++i)
554    EdgeTable[i] = NullValue;
555
556  unsigned Edge = 0;
557  for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
558    TerminatorInst *TI = BB->getTerminator();
559    int Successors = isa<ReturnInst>(TI) ? 1 : TI->getNumSuccessors();
560    if (Successors > 1 && !isa<BranchInst>(TI) && !isa<ReturnInst>(TI)) {
561      for (int i = 0; i != Successors; ++i) {
562        BasicBlock *Succ = TI->getSuccessor(i);
563        IRBuilder<> Builder(Succ);
564        Value *Counter = Builder.CreateConstInBoundsGEP2_64(Counters, 0,
565                                                            Edge + i);
566        EdgeTable[((Succs.idFor(Succ)-1) * Preds.size()) +
567                  (Preds.idFor(BB)-1)] = cast<Constant>(Counter);
568      }
569    }
570    Edge += Successors;
571  }
572
573  ArrayRef<Constant*> V(&EdgeTable[0], TableSize);
574  GlobalVariable *EdgeTableGV =
575      new GlobalVariable(
576          *M, EdgeTableTy, true, GlobalValue::InternalLinkage,
577          ConstantArray::get(EdgeTableTy, V),
578          "__llvm_gcda_edge_table");
579  EdgeTableGV->setUnnamedAddr(true);
580  return EdgeTableGV;
581}
582
583Constant *GCOVProfiler::getStartFileFunc() {
584  Type *Args[] = {
585    Type::getInt8PtrTy(*Ctx),  // const char *orig_filename
586    Type::getInt8PtrTy(*Ctx),  // const char version[4]
587  };
588  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false);
589  return M->getOrInsertFunction("llvm_gcda_start_file", FTy);
590}
591
592Constant *GCOVProfiler::getIncrementIndirectCounterFunc() {
593  Type *Int32Ty = Type::getInt32Ty(*Ctx);
594  Type *Int64Ty = Type::getInt64Ty(*Ctx);
595  Type *Args[] = {
596    Int32Ty->getPointerTo(),                // uint32_t *predecessor
597    Int64Ty->getPointerTo()->getPointerTo() // uint64_t **counters
598  };
599  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false);
600  return M->getOrInsertFunction("__llvm_gcov_indirect_counter_increment", FTy);
601}
602
603Constant *GCOVProfiler::getEmitFunctionFunc() {
604  Type *Args[2] = {
605    Type::getInt32Ty(*Ctx),    // uint32_t ident
606    Type::getInt8PtrTy(*Ctx),  // const char *function_name
607  };
608  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false);
609  return M->getOrInsertFunction("llvm_gcda_emit_function", FTy);
610}
611
612Constant *GCOVProfiler::getEmitArcsFunc() {
613  Type *Args[] = {
614    Type::getInt32Ty(*Ctx),     // uint32_t num_counters
615    Type::getInt64PtrTy(*Ctx),  // uint64_t *counters
616  };
617  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false);
618  return M->getOrInsertFunction("llvm_gcda_emit_arcs", FTy);
619}
620
621Constant *GCOVProfiler::getEndFileFunc() {
622  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
623  return M->getOrInsertFunction("llvm_gcda_end_file", FTy);
624}
625
626GlobalVariable *GCOVProfiler::getEdgeStateValue() {
627  GlobalVariable *GV = M->getGlobalVariable("__llvm_gcov_global_state_pred");
628  if (!GV) {
629    GV = new GlobalVariable(*M, Type::getInt32Ty(*Ctx), false,
630                            GlobalValue::InternalLinkage,
631                            ConstantInt::get(Type::getInt32Ty(*Ctx),
632                                             0xffffffff),
633                            "__llvm_gcov_global_state_pred");
634    GV->setUnnamedAddr(true);
635  }
636  return GV;
637}
638
639void GCOVProfiler::insertCounterWriteout(
640    ArrayRef<std::pair<GlobalVariable *, MDNode *> > CountersBySP) {
641  FunctionType *WriteoutFTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
642  Function *WriteoutF = M->getFunction("__llvm_gcov_writeout");
643  if (!WriteoutF)
644    WriteoutF = Function::Create(WriteoutFTy, GlobalValue::InternalLinkage,
645                                 "__llvm_gcov_writeout", M);
646  WriteoutF->setUnnamedAddr(true);
647  WriteoutF->addFnAttr(Attribute::NoInline);
648  if (NoRedZone)
649    WriteoutF->addFnAttr(Attribute::NoRedZone);
650
651  BasicBlock *BB = BasicBlock::Create(*Ctx, "entry", WriteoutF);
652  IRBuilder<> Builder(BB);
653
654  Constant *StartFile = getStartFileFunc();
655  Constant *EmitFunction = getEmitFunctionFunc();
656  Constant *EmitArcs = getEmitArcsFunc();
657  Constant *EndFile = getEndFileFunc();
658
659  NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
660  if (CU_Nodes) {
661    for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
662      DICompileUnit CU(CU_Nodes->getOperand(i));
663      std::string FilenameGcda = mangleName(CU, "gcda");
664      Builder.CreateCall2(StartFile,
665                          Builder.CreateGlobalStringPtr(FilenameGcda),
666                          Builder.CreateGlobalStringPtr(Version));
667      for (ArrayRef<std::pair<GlobalVariable *, MDNode *> >::iterator
668             I = CountersBySP.begin(), E = CountersBySP.end();
669           I != E; ++I) {
670        DISubprogram SP(I->second);
671        Builder.CreateCall2(EmitFunction,
672                            Builder.getInt32(i),
673                            NoFunctionNamesInData ?
674                              Constant::getNullValue(Builder.getInt8PtrTy()) :
675                              Builder.CreateGlobalStringPtr(SP.getName()));
676
677        GlobalVariable *GV = I->first;
678        unsigned Arcs =
679          cast<ArrayType>(GV->getType()->getElementType())->getNumElements();
680        Builder.CreateCall2(EmitArcs,
681                            Builder.getInt32(Arcs),
682                            Builder.CreateConstGEP2_64(GV, 0, 0));
683      }
684      Builder.CreateCall(EndFile);
685    }
686  }
687  Builder.CreateRetVoid();
688
689  // Create a small bit of code that registers the "__llvm_gcov_writeout"
690  // function to be executed at exit.
691  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
692  Function *F = Function::Create(FTy, GlobalValue::InternalLinkage,
693                                 "__llvm_gcov_init", M);
694  F->setUnnamedAddr(true);
695  F->setLinkage(GlobalValue::InternalLinkage);
696  F->addFnAttr(Attribute::NoInline);
697  if (NoRedZone)
698    F->addFnAttr(Attribute::NoRedZone);
699
700  BB = BasicBlock::Create(*Ctx, "entry", F);
701  Builder.SetInsertPoint(BB);
702
703  FTy = FunctionType::get(Builder.getInt32Ty(),
704                          PointerType::get(FTy, 0), false);
705  Constant *AtExitFn = M->getOrInsertFunction("atexit", FTy);
706  Builder.CreateCall(AtExitFn, WriteoutF);
707  Builder.CreateRetVoid();
708
709  appendToGlobalCtors(*M, F, 0);
710}
711
712void GCOVProfiler::insertIndirectCounterIncrement() {
713  Function *Fn =
714    cast<Function>(GCOVProfiler::getIncrementIndirectCounterFunc());
715  Fn->setUnnamedAddr(true);
716  Fn->setLinkage(GlobalValue::InternalLinkage);
717  Fn->addFnAttr(Attribute::NoInline);
718  if (NoRedZone)
719    Fn->addFnAttr(Attribute::NoRedZone);
720
721  // Create basic blocks for function.
722  BasicBlock *BB = BasicBlock::Create(*Ctx, "entry", Fn);
723  IRBuilder<> Builder(BB);
724
725  BasicBlock *PredNotNegOne = BasicBlock::Create(*Ctx, "", Fn);
726  BasicBlock *CounterEnd = BasicBlock::Create(*Ctx, "", Fn);
727  BasicBlock *Exit = BasicBlock::Create(*Ctx, "exit", Fn);
728
729  // uint32_t pred = *predecessor;
730  // if (pred == 0xffffffff) return;
731  Argument *Arg = Fn->arg_begin();
732  Arg->setName("predecessor");
733  Value *Pred = Builder.CreateLoad(Arg, "pred");
734  Value *Cond = Builder.CreateICmpEQ(Pred, Builder.getInt32(0xffffffff));
735  BranchInst::Create(Exit, PredNotNegOne, Cond, BB);
736
737  Builder.SetInsertPoint(PredNotNegOne);
738
739  // uint64_t *counter = counters[pred];
740  // if (!counter) return;
741  Value *ZExtPred = Builder.CreateZExt(Pred, Builder.getInt64Ty());
742  Arg = llvm::next(Fn->arg_begin());
743  Arg->setName("counters");
744  Value *GEP = Builder.CreateGEP(Arg, ZExtPred);
745  Value *Counter = Builder.CreateLoad(GEP, "counter");
746  Cond = Builder.CreateICmpEQ(Counter,
747                              Constant::getNullValue(
748                                  Builder.getInt64Ty()->getPointerTo()));
749  Builder.CreateCondBr(Cond, Exit, CounterEnd);
750
751  // ++*counter;
752  Builder.SetInsertPoint(CounterEnd);
753  Value *Add = Builder.CreateAdd(Builder.CreateLoad(Counter),
754                                 Builder.getInt64(1));
755  Builder.CreateStore(Add, Counter);
756  Builder.CreateBr(Exit);
757
758  // Fill in the exit block.
759  Builder.SetInsertPoint(Exit);
760  Builder.CreateRetVoid();
761}
762
763void GCOVProfiler::
764insertFlush(ArrayRef<std::pair<GlobalVariable*, MDNode*> > CountersBySP) {
765  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
766  Function *FlushF = M->getFunction("__gcov_flush");
767  if (!FlushF)
768    FlushF = Function::Create(FTy, GlobalValue::InternalLinkage,
769                              "__gcov_flush", M);
770  else
771    FlushF->setLinkage(GlobalValue::InternalLinkage);
772  FlushF->setUnnamedAddr(true);
773  FlushF->addFnAttr(Attribute::NoInline);
774  if (NoRedZone)
775    FlushF->addFnAttr(Attribute::NoRedZone);
776
777  BasicBlock *Entry = BasicBlock::Create(*Ctx, "entry", FlushF);
778
779  // Write out the current counters.
780  Constant *WriteoutF = M->getFunction("__llvm_gcov_writeout");
781  assert(WriteoutF && "Need to create the writeout function first!");
782
783  IRBuilder<> Builder(Entry);
784  Builder.CreateCall(WriteoutF);
785
786  // Zero out the counters.
787  for (ArrayRef<std::pair<GlobalVariable *, MDNode *> >::iterator
788         I = CountersBySP.begin(), E = CountersBySP.end();
789       I != E; ++I) {
790    GlobalVariable *GV = I->first;
791    Constant *Null = Constant::getNullValue(GV->getType()->getElementType());
792    Builder.CreateStore(Null, GV);
793  }
794
795  Type *RetTy = FlushF->getReturnType();
796  if (RetTy == Type::getVoidTy(*Ctx))
797    Builder.CreateRetVoid();
798  else if (RetTy->isIntegerTy())
799    // Used if __gcov_flush was implicitly declared.
800    Builder.CreateRet(ConstantInt::get(RetTy, 0));
801  else
802    report_fatal_error("invalid return type for __gcov_flush");
803}
804