GCOVProfiling.cpp revision 0b8c9a80f20772c3793201ab5b251d3520b9cea3 
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), Use402Format(false),
48          UseExtraChecksum(false), NoRedZone(false) {
49      initializeGCOVProfilerPass(*PassRegistry::getPassRegistry());
50    }
51    GCOVProfiler(bool EmitNotes, bool EmitData, bool use402Format,
52                 bool useExtraChecksum, bool NoRedZone_)
53        : ModulePass(ID), EmitNotes(EmitNotes), EmitData(EmitData),
54          Use402Format(use402Format), UseExtraChecksum(useExtraChecksum),
55          NoRedZone(NoRedZone_) {
56      assert((EmitNotes || EmitData) && "GCOVProfiler asked to do nothing?");
57      initializeGCOVProfilerPass(*PassRegistry::getPassRegistry());
58    }
59    virtual const char *getPassName() const {
60      return "GCOV Profiler";
61    }
62  private:
63    bool runOnModule(Module &M);
64
65    // Create the GCNO files for the Module based on DebugInfo.
66    void emitGCNO();
67
68    // Modify the program to track transitions along edges and call into the
69    // profiling runtime to emit .gcda files when run.
70    bool emitProfileArcs();
71
72    // Get pointers to the functions in the runtime library.
73    Constant *getStartFileFunc();
74    Constant *getIncrementIndirectCounterFunc();
75    Constant *getEmitFunctionFunc();
76    Constant *getEmitArcsFunc();
77    Constant *getEndFileFunc();
78
79    // Create or retrieve an i32 state value that is used to represent the
80    // pred block number for certain non-trivial edges.
81    GlobalVariable *getEdgeStateValue();
82
83    // Produce a table of pointers to counters, by predecessor and successor
84    // block number.
85    GlobalVariable *buildEdgeLookupTable(Function *F,
86                                         GlobalVariable *Counter,
87                                         const UniqueVector<BasicBlock *> &Preds,
88                                         const UniqueVector<BasicBlock *> &Succs);
89
90    // Add the function to write out all our counters to the global destructor
91    // list.
92    void insertCounterWriteout(ArrayRef<std::pair<GlobalVariable*, MDNode*> >);
93    void insertIndirectCounterIncrement();
94    void insertFlush(ArrayRef<std::pair<GlobalVariable*, MDNode*> >);
95
96    std::string mangleName(DICompileUnit CU, const char *NewStem);
97
98    bool EmitNotes;
99    bool EmitData;
100    bool Use402Format;
101    bool UseExtraChecksum;
102    bool NoRedZone;
103
104    Module *M;
105    LLVMContext *Ctx;
106  };
107}
108
109char GCOVProfiler::ID = 0;
110INITIALIZE_PASS(GCOVProfiler, "insert-gcov-profiling",
111                "Insert instrumentation for GCOV profiling", false, false)
112
113ModulePass *llvm::createGCOVProfilerPass(bool EmitNotes, bool EmitData,
114                                         bool Use402Format,
115                                         bool UseExtraChecksum,
116                                         bool NoRedZone) {
117  return new GCOVProfiler(EmitNotes, EmitData, Use402Format, UseExtraChecksum,
118                          NoRedZone);
119}
120
121namespace {
122  class GCOVRecord {
123   protected:
124    static const char *LinesTag;
125    static const char *FunctionTag;
126    static const char *BlockTag;
127    static const char *EdgeTag;
128
129    GCOVRecord() {}
130
131    void writeBytes(const char *Bytes, int Size) {
132      os->write(Bytes, Size);
133    }
134
135    void write(uint32_t i) {
136      writeBytes(reinterpret_cast<char*>(&i), 4);
137    }
138
139    // Returns the length measured in 4-byte blocks that will be used to
140    // represent this string in a GCOV file
141    unsigned lengthOfGCOVString(StringRef s) {
142      // A GCOV string is a length, followed by a NUL, then between 0 and 3 NULs
143      // padding out to the next 4-byte word. The length is measured in 4-byte
144      // words including padding, not bytes of actual string.
145      return (s.size() / 4) + 1;
146    }
147
148    void writeGCOVString(StringRef s) {
149      uint32_t Len = lengthOfGCOVString(s);
150      write(Len);
151      writeBytes(s.data(), s.size());
152
153      // Write 1 to 4 bytes of NUL padding.
154      assert((unsigned)(4 - (s.size() % 4)) > 0);
155      assert((unsigned)(4 - (s.size() % 4)) <= 4);
156      writeBytes("\0\0\0\0", 4 - (s.size() % 4));
157    }
158
159    raw_ostream *os;
160  };
161  const char *GCOVRecord::LinesTag = "\0\0\x45\x01";
162  const char *GCOVRecord::FunctionTag = "\0\0\0\1";
163  const char *GCOVRecord::BlockTag = "\0\0\x41\x01";
164  const char *GCOVRecord::EdgeTag = "\0\0\x43\x01";
165
166  class GCOVFunction;
167  class GCOVBlock;
168
169  // Constructed only by requesting it from a GCOVBlock, this object stores a
170  // list of line numbers and a single filename, representing lines that belong
171  // to the block.
172  class GCOVLines : public GCOVRecord {
173   public:
174    void addLine(uint32_t Line) {
175      Lines.push_back(Line);
176    }
177
178    uint32_t length() {
179      // Here 2 = 1 for string length + 1 for '0' id#.
180      return lengthOfGCOVString(Filename) + 2 + Lines.size();
181    }
182
183    void writeOut() {
184      write(0);
185      writeGCOVString(Filename);
186      for (int i = 0, e = Lines.size(); i != e; ++i)
187        write(Lines[i]);
188    }
189
190    GCOVLines(StringRef F, raw_ostream *os)
191      : Filename(F) {
192      this->os = os;
193    }
194
195   private:
196    StringRef Filename;
197    SmallVector<uint32_t, 32> Lines;
198  };
199
200  // Represent a basic block in GCOV. Each block has a unique number in the
201  // function, number of lines belonging to each block, and a set of edges to
202  // other blocks.
203  class GCOVBlock : public GCOVRecord {
204   public:
205    GCOVLines &getFile(StringRef Filename) {
206      GCOVLines *&Lines = LinesByFile[Filename];
207      if (!Lines) {
208        Lines = new GCOVLines(Filename, os);
209      }
210      return *Lines;
211    }
212
213    void addEdge(GCOVBlock &Successor) {
214      OutEdges.push_back(&Successor);
215    }
216
217    void writeOut() {
218      uint32_t Len = 3;
219      for (StringMap<GCOVLines *>::iterator I = LinesByFile.begin(),
220               E = LinesByFile.end(); I != E; ++I) {
221        Len += I->second->length();
222      }
223
224      writeBytes(LinesTag, 4);
225      write(Len);
226      write(Number);
227      for (StringMap<GCOVLines *>::iterator I = LinesByFile.begin(),
228               E = LinesByFile.end(); I != E; ++I)
229        I->second->writeOut();
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,
257                 bool Use402Format, bool UseExtraChecksum) {
258      this->os = os;
259
260      Function *F = SP.getFunction();
261      DEBUG(dbgs() << "Function: " << F->getName() << "\n");
262      uint32_t i = 0;
263      for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
264        Blocks[BB] = new GCOVBlock(i++, os);
265      }
266      ReturnBlock = new GCOVBlock(i++, os);
267
268      writeBytes(FunctionTag, 4);
269      uint32_t BlockLen = 1 + 1 + 1 + lengthOfGCOVString(SP.getName()) +
270          1 + lengthOfGCOVString(SP.getFilename()) + 1;
271      if (UseExtraChecksum)
272        ++BlockLen;
273      write(BlockLen);
274      uint32_t Ident = reinterpret_cast<intptr_t>((MDNode*)SP);
275      write(Ident);
276      write(0);  // lineno checksum
277      if (UseExtraChecksum)
278        write(0);  // cfg checksum
279      writeGCOVString(SP.getName());
280      writeGCOVString(SP.getFilename());
281      write(SP.getLineNumber());
282    }
283
284    ~GCOVFunction() {
285      DeleteContainerSeconds(Blocks);
286      delete ReturnBlock;
287    }
288
289    GCOVBlock &getBlock(BasicBlock *BB) {
290      return *Blocks[BB];
291    }
292
293    GCOVBlock &getReturnBlock() {
294      return *ReturnBlock;
295    }
296
297    void writeOut() {
298      // Emit count of blocks.
299      writeBytes(BlockTag, 4);
300      write(Blocks.size() + 1);
301      for (int i = 0, e = Blocks.size() + 1; i != e; ++i) {
302        write(0);  // No flags on our blocks.
303      }
304      DEBUG(dbgs() << Blocks.size() << " blocks.\n");
305
306      // Emit edges between blocks.
307      for (DenseMap<BasicBlock *, GCOVBlock *>::iterator I = Blocks.begin(),
308               E = Blocks.end(); I != E; ++I) {
309        GCOVBlock &Block = *I->second;
310        if (Block.OutEdges.empty()) continue;
311
312        writeBytes(EdgeTag, 4);
313        write(Block.OutEdges.size() * 2 + 1);
314        write(Block.Number);
315        for (int i = 0, e = Block.OutEdges.size(); i != e; ++i) {
316          DEBUG(dbgs() << Block.Number << " -> " << Block.OutEdges[i]->Number
317                       << "\n");
318          write(Block.OutEdges[i]->Number);
319          write(0);  // no flags
320        }
321      }
322
323      // Emit lines for each block.
324      for (DenseMap<BasicBlock *, GCOVBlock *>::iterator I = Blocks.begin(),
325               E = Blocks.end(); I != E; ++I) {
326        I->second->writeOut();
327      }
328    }
329
330   private:
331    DenseMap<BasicBlock *, GCOVBlock *> Blocks;
332    GCOVBlock *ReturnBlock;
333  };
334}
335
336std::string GCOVProfiler::mangleName(DICompileUnit CU, const char *NewStem) {
337  if (NamedMDNode *GCov = M->getNamedMetadata("llvm.gcov")) {
338    for (int i = 0, e = GCov->getNumOperands(); i != e; ++i) {
339      MDNode *N = GCov->getOperand(i);
340      if (N->getNumOperands() != 2) continue;
341      MDString *GCovFile = dyn_cast<MDString>(N->getOperand(0));
342      MDNode *CompileUnit = dyn_cast<MDNode>(N->getOperand(1));
343      if (!GCovFile || !CompileUnit) continue;
344      if (CompileUnit == CU) {
345        SmallString<128> Filename = GCovFile->getString();
346        sys::path::replace_extension(Filename, NewStem);
347        return Filename.str();
348      }
349    }
350  }
351
352  SmallString<128> Filename = CU.getFilename();
353  sys::path::replace_extension(Filename, NewStem);
354  return sys::path::filename(Filename.str());
355}
356
357bool GCOVProfiler::runOnModule(Module &M) {
358  this->M = &M;
359  Ctx = &M.getContext();
360
361  if (EmitNotes) emitGCNO();
362  if (EmitData) return emitProfileArcs();
363  return false;
364}
365
366void GCOVProfiler::emitGCNO() {
367  NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
368  if (!CU_Nodes) return;
369
370  for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
371    // Each compile unit gets its own .gcno file. This means that whether we run
372    // this pass over the original .o's as they're produced, or run it after
373    // LTO, we'll generate the same .gcno files.
374
375    DICompileUnit CU(CU_Nodes->getOperand(i));
376    std::string ErrorInfo;
377    raw_fd_ostream out(mangleName(CU, "gcno").c_str(), ErrorInfo,
378                       raw_fd_ostream::F_Binary);
379    if (!Use402Format)
380      out.write("oncg*404MVLL", 12);
381    else
382      out.write("oncg*204MVLL", 12);
383
384    DIArray SPs = CU.getSubprograms();
385    for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i) {
386      DISubprogram SP(SPs.getElement(i));
387      if (!SP.Verify()) continue;
388
389      Function *F = SP.getFunction();
390      if (!F) continue;
391      GCOVFunction Func(SP, &out, Use402Format, UseExtraChecksum);
392
393      for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
394        GCOVBlock &Block = Func.getBlock(BB);
395        TerminatorInst *TI = BB->getTerminator();
396        if (int successors = TI->getNumSuccessors()) {
397          for (int i = 0; i != successors; ++i) {
398            Block.addEdge(Func.getBlock(TI->getSuccessor(i)));
399          }
400        } else if (isa<ReturnInst>(TI)) {
401          Block.addEdge(Func.getReturnBlock());
402        }
403
404        uint32_t Line = 0;
405        for (BasicBlock::iterator I = BB->begin(), IE = BB->end();
406             I != IE; ++I) {
407          const DebugLoc &Loc = I->getDebugLoc();
408          if (Loc.isUnknown()) continue;
409          if (Line == Loc.getLine()) continue;
410          Line = Loc.getLine();
411          if (SP != getDISubprogram(Loc.getScope(*Ctx))) continue;
412
413          GCOVLines &Lines = Block.getFile(SP.getFilename());
414          Lines.addLine(Loc.getLine());
415        }
416      }
417      Func.writeOut();
418    }
419    out.write("\0\0\0\0\0\0\0\0", 8);  // EOF
420    out.close();
421  }
422}
423
424bool GCOVProfiler::emitProfileArcs() {
425  NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
426  if (!CU_Nodes) return false;
427
428  bool Result = false;
429  bool InsertIndCounterIncrCode = false;
430  for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
431    DICompileUnit CU(CU_Nodes->getOperand(i));
432    DIArray SPs = CU.getSubprograms();
433    SmallVector<std::pair<GlobalVariable *, MDNode *>, 8> CountersBySP;
434    for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i) {
435      DISubprogram SP(SPs.getElement(i));
436      if (!SP.Verify()) continue;
437      Function *F = SP.getFunction();
438      if (!F) continue;
439      if (!Result) Result = true;
440      unsigned Edges = 0;
441      for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
442        TerminatorInst *TI = BB->getTerminator();
443        if (isa<ReturnInst>(TI))
444          ++Edges;
445        else
446          Edges += TI->getNumSuccessors();
447      }
448
449      ArrayType *CounterTy =
450        ArrayType::get(Type::getInt64Ty(*Ctx), Edges);
451      GlobalVariable *Counters =
452        new GlobalVariable(*M, CounterTy, false,
453                           GlobalValue::InternalLinkage,
454                           Constant::getNullValue(CounterTy),
455                           "__llvm_gcov_ctr");
456      CountersBySP.push_back(std::make_pair(Counters, (MDNode*)SP));
457
458      UniqueVector<BasicBlock *> ComplexEdgePreds;
459      UniqueVector<BasicBlock *> ComplexEdgeSuccs;
460
461      unsigned Edge = 0;
462      for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
463        TerminatorInst *TI = BB->getTerminator();
464        int Successors = isa<ReturnInst>(TI) ? 1 : TI->getNumSuccessors();
465        if (Successors) {
466          IRBuilder<> Builder(TI);
467
468          if (Successors == 1) {
469            Value *Counter = Builder.CreateConstInBoundsGEP2_64(Counters, 0,
470                                                                Edge);
471            Value *Count = Builder.CreateLoad(Counter);
472            Count = Builder.CreateAdd(Count,
473                                      ConstantInt::get(Type::getInt64Ty(*Ctx),1));
474            Builder.CreateStore(Count, Counter);
475          } else if (BranchInst *BI = dyn_cast<BranchInst>(TI)) {
476            Value *Sel = Builder.CreateSelect(
477              BI->getCondition(),
478              ConstantInt::get(Type::getInt64Ty(*Ctx), Edge),
479              ConstantInt::get(Type::getInt64Ty(*Ctx), Edge + 1));
480            SmallVector<Value *, 2> Idx;
481            Idx.push_back(Constant::getNullValue(Type::getInt64Ty(*Ctx)));
482            Idx.push_back(Sel);
483            Value *Counter = Builder.CreateInBoundsGEP(Counters, Idx);
484            Value *Count = Builder.CreateLoad(Counter);
485            Count = Builder.CreateAdd(Count,
486                                      ConstantInt::get(Type::getInt64Ty(*Ctx),1));
487            Builder.CreateStore(Count, Counter);
488          } else {
489            ComplexEdgePreds.insert(BB);
490            for (int i = 0; i != Successors; ++i)
491              ComplexEdgeSuccs.insert(TI->getSuccessor(i));
492          }
493          Edge += Successors;
494        }
495      }
496
497      if (!ComplexEdgePreds.empty()) {
498        GlobalVariable *EdgeTable =
499          buildEdgeLookupTable(F, Counters,
500                               ComplexEdgePreds, ComplexEdgeSuccs);
501        GlobalVariable *EdgeState = getEdgeStateValue();
502
503        Type *Int32Ty = Type::getInt32Ty(*Ctx);
504        for (int i = 0, e = ComplexEdgePreds.size(); i != e; ++i) {
505          IRBuilder<> Builder(ComplexEdgePreds[i+1]->getTerminator());
506          Builder.CreateStore(ConstantInt::get(Int32Ty, 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  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx),
585                                              Type::getInt8PtrTy(*Ctx), false);
586  return M->getOrInsertFunction("llvm_gcda_start_file", FTy);
587}
588
589Constant *GCOVProfiler::getIncrementIndirectCounterFunc() {
590  Type *Int32Ty = Type::getInt32Ty(*Ctx);
591  Type *Int64Ty = Type::getInt64Ty(*Ctx);
592  Type *Args[] = {
593    Int32Ty->getPointerTo(),                // uint32_t *predecessor
594    Int64Ty->getPointerTo()->getPointerTo() // uint64_t **counters
595  };
596  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false);
597  return M->getOrInsertFunction("__llvm_gcov_indirect_counter_increment", FTy);
598}
599
600Constant *GCOVProfiler::getEmitFunctionFunc() {
601  Type *Args[2] = {
602    Type::getInt32Ty(*Ctx),    // uint32_t ident
603    Type::getInt8PtrTy(*Ctx),  // const char *function_name
604  };
605  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false);
606  return M->getOrInsertFunction("llvm_gcda_emit_function", FTy);
607}
608
609Constant *GCOVProfiler::getEmitArcsFunc() {
610  Type *Args[] = {
611    Type::getInt32Ty(*Ctx),     // uint32_t num_counters
612    Type::getInt64PtrTy(*Ctx),  // uint64_t *counters
613  };
614  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx),
615                                              Args, false);
616  return M->getOrInsertFunction("llvm_gcda_emit_arcs", FTy);
617}
618
619Constant *GCOVProfiler::getEndFileFunc() {
620  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
621  return M->getOrInsertFunction("llvm_gcda_end_file", FTy);
622}
623
624GlobalVariable *GCOVProfiler::getEdgeStateValue() {
625  GlobalVariable *GV = M->getGlobalVariable("__llvm_gcov_global_state_pred");
626  if (!GV) {
627    GV = new GlobalVariable(*M, Type::getInt32Ty(*Ctx), false,
628                            GlobalValue::InternalLinkage,
629                            ConstantInt::get(Type::getInt32Ty(*Ctx),
630                                             0xffffffff),
631                            "__llvm_gcov_global_state_pred");
632    GV->setUnnamedAddr(true);
633  }
634  return GV;
635}
636
637void GCOVProfiler::insertCounterWriteout(
638    ArrayRef<std::pair<GlobalVariable *, MDNode *> > CountersBySP) {
639  FunctionType *WriteoutFTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
640  Function *WriteoutF = M->getFunction("__llvm_gcov_writeout");
641  if (!WriteoutF)
642    WriteoutF = Function::Create(WriteoutFTy, GlobalValue::InternalLinkage,
643                                 "__llvm_gcov_writeout", M);
644  WriteoutF->setUnnamedAddr(true);
645  WriteoutF->addFnAttr(Attribute::NoInline);
646  if (NoRedZone)
647    WriteoutF->addFnAttr(Attribute::NoRedZone);
648
649  BasicBlock *BB = BasicBlock::Create(*Ctx, "entry", WriteoutF);
650  IRBuilder<> Builder(BB);
651
652  Constant *StartFile = getStartFileFunc();
653  Constant *EmitFunction = getEmitFunctionFunc();
654  Constant *EmitArcs = getEmitArcsFunc();
655  Constant *EndFile = getEndFileFunc();
656
657  NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
658  if (CU_Nodes) {
659    for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
660      DICompileUnit CU(CU_Nodes->getOperand(i));
661      std::string FilenameGcda = mangleName(CU, "gcda");
662      Builder.CreateCall(StartFile,
663                         Builder.CreateGlobalStringPtr(FilenameGcda));
664      for (ArrayRef<std::pair<GlobalVariable *, MDNode *> >::iterator
665             I = CountersBySP.begin(), E = CountersBySP.end();
666           I != E; ++I) {
667        DISubprogram SP(I->second);
668        intptr_t ident = reinterpret_cast<intptr_t>(I->second);
669        Builder.CreateCall2(EmitFunction,
670                            ConstantInt::get(Type::getInt32Ty(*Ctx), ident),
671                            Builder.CreateGlobalStringPtr(SP.getName()));
672
673        GlobalVariable *GV = I->first;
674        unsigned Arcs =
675          cast<ArrayType>(GV->getType()->getElementType())->getNumElements();
676        Builder.CreateCall2(EmitArcs,
677                            ConstantInt::get(Type::getInt32Ty(*Ctx), Arcs),
678                            Builder.CreateConstGEP2_64(GV, 0, 0));
679      }
680      Builder.CreateCall(EndFile);
681    }
682  }
683  Builder.CreateRetVoid();
684
685  // Create a small bit of code that registers the "__llvm_gcov_writeout"
686  // function to be executed at exit.
687  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
688  Function *F = Function::Create(FTy, GlobalValue::InternalLinkage,
689                                 "__llvm_gcov_init", M);
690  F->setUnnamedAddr(true);
691  F->setLinkage(GlobalValue::InternalLinkage);
692  F->addFnAttr(Attribute::NoInline);
693  if (NoRedZone)
694    F->addFnAttr(Attribute::NoRedZone);
695
696  BB = BasicBlock::Create(*Ctx, "entry", F);
697  Builder.SetInsertPoint(BB);
698
699  FTy = FunctionType::get(Type::getInt32Ty(*Ctx),
700                          PointerType::get(FTy, 0), false);
701  Constant *AtExitFn = M->getOrInsertFunction("atexit", FTy);
702  Builder.CreateCall(AtExitFn, WriteoutF);
703  Builder.CreateRetVoid();
704
705  appendToGlobalCtors(*M, F, 0);
706}
707
708void GCOVProfiler::insertIndirectCounterIncrement() {
709  Function *Fn =
710    cast<Function>(GCOVProfiler::getIncrementIndirectCounterFunc());
711  Fn->setUnnamedAddr(true);
712  Fn->setLinkage(GlobalValue::InternalLinkage);
713  Fn->addFnAttr(Attribute::NoInline);
714  if (NoRedZone)
715    Fn->addFnAttr(Attribute::NoRedZone);
716
717  Type *Int32Ty = Type::getInt32Ty(*Ctx);
718  Type *Int64Ty = Type::getInt64Ty(*Ctx);
719  Constant *NegOne = ConstantInt::get(Int32Ty, 0xffffffff);
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, NegOne);
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, Int64Ty);
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(Int64Ty->getPointerTo()));
748  Builder.CreateCondBr(Cond, Exit, CounterEnd);
749
750  // ++*counter;
751  Builder.SetInsertPoint(CounterEnd);
752  Value *Add = Builder.CreateAdd(Builder.CreateLoad(Counter),
753                                 ConstantInt::get(Int64Ty, 1));
754  Builder.CreateStore(Add, Counter);
755  Builder.CreateBr(Exit);
756
757  // Fill in the exit block.
758  Builder.SetInsertPoint(Exit);
759  Builder.CreateRetVoid();
760}
761
762void GCOVProfiler::
763insertFlush(ArrayRef<std::pair<GlobalVariable*, MDNode*> > CountersBySP) {
764  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
765  Function *FlushF = M->getFunction("__gcov_flush");
766  if (!FlushF)
767    FlushF = Function::Create(FTy, GlobalValue::InternalLinkage,
768                              "__gcov_flush", M);
769  else
770    FlushF->setLinkage(GlobalValue::InternalLinkage);
771  FlushF->setUnnamedAddr(true);
772  FlushF->addFnAttr(Attribute::NoInline);
773  if (NoRedZone)
774    FlushF->addFnAttr(Attribute::NoRedZone);
775
776  BasicBlock *Entry = BasicBlock::Create(*Ctx, "entry", FlushF);
777
778  // Write out the current counters.
779  Constant *WriteoutF = M->getFunction("__llvm_gcov_writeout");
780  assert(WriteoutF && "Need to create the writeout function first!");
781
782  IRBuilder<> Builder(Entry);
783  Builder.CreateCall(WriteoutF);
784
785  // Zero out the counters.
786  for (ArrayRef<std::pair<GlobalVariable *, MDNode *> >::iterator
787         I = CountersBySP.begin(), E = CountersBySP.end();
788       I != E; ++I) {
789    GlobalVariable *GV = I->first;
790    Constant *Null = Constant::getNullValue(GV->getType()->getElementType());
791    Builder.CreateStore(Null, GV);
792  }
793
794  Type *RetTy = FlushF->getReturnType();
795  if (RetTy == Type::getVoidTy(*Ctx))
796    Builder.CreateRetVoid();
797  else if (RetTy->isIntegerTy())
798    // Used if __gcov_flush was implicitly declared.
799    Builder.CreateRet(ConstantInt::get(RetTy, 0));
800  else
801    report_fatal_error("invalid return type for __gcov_flush");
802}
803