GCOVProfiling.cpp revision 9e6ee16b1814268897965b81e82a74ef39173ee1 
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/DebugInfo.h"
22#include "llvm/IRBuilder.h"
23#include "llvm/Instructions.h"
24#include "llvm/Module.h"
25#include "llvm/Pass.h"
26#include "llvm/ADT/DenseMap.h"
27#include "llvm/ADT/STLExtras.h"
28#include "llvm/ADT/Statistic.h"
29#include "llvm/ADT/StringExtras.h"
30#include "llvm/ADT/StringMap.h"
31#include "llvm/ADT/UniqueVector.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) {
49      initializeGCOVProfilerPass(*PassRegistry::getPassRegistry());
50    }
51    GCOVProfiler(bool EmitNotes, bool EmitData, bool use402Format = false,
52                 bool useExtraChecksum = false)
53        : ModulePass(ID), EmitNotes(EmitNotes), EmitData(EmitData),
54          Use402Format(use402Format), UseExtraChecksum(useExtraChecksum) {
55      assert((EmitNotes || EmitData) && "GCOVProfiler asked to do nothing?");
56      initializeGCOVProfilerPass(*PassRegistry::getPassRegistry());
57    }
58    virtual const char *getPassName() const {
59      return "GCOV Profiler";
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(ArrayRef<std::pair<GlobalVariable*, MDNode*> >);
92    void insertIndirectCounterIncrement();
93    void insertFlush(ArrayRef<std::pair<GlobalVariable*, MDNode*> >);
94
95    std::string mangleName(DICompileUnit CU, const char *NewStem);
96
97    bool EmitNotes;
98    bool EmitData;
99    bool Use402Format;
100    bool UseExtraChecksum;
101
102    Module *M;
103    LLVMContext *Ctx;
104  };
105}
106
107char GCOVProfiler::ID = 0;
108INITIALIZE_PASS(GCOVProfiler, "insert-gcov-profiling",
109                "Insert instrumentation for GCOV profiling", false, false)
110
111ModulePass *llvm::createGCOVProfilerPass(bool EmitNotes, bool EmitData,
112                                         bool Use402Format,
113                                         bool UseExtraChecksum) {
114  return new GCOVProfiler(EmitNotes, EmitData, Use402Format, UseExtraChecksum);
115}
116
117namespace {
118  class GCOVRecord {
119   protected:
120    static const char *LinesTag;
121    static const char *FunctionTag;
122    static const char *BlockTag;
123    static const char *EdgeTag;
124
125    GCOVRecord() {}
126
127    void writeBytes(const char *Bytes, int Size) {
128      os->write(Bytes, Size);
129    }
130
131    void write(uint32_t i) {
132      writeBytes(reinterpret_cast<char*>(&i), 4);
133    }
134
135    // Returns the length measured in 4-byte blocks that will be used to
136    // represent this string in a GCOV file
137    unsigned lengthOfGCOVString(StringRef s) {
138      // A GCOV string is a length, followed by a NUL, then between 0 and 3 NULs
139      // padding out to the next 4-byte word. The length is measured in 4-byte
140      // words including padding, not bytes of actual string.
141      return (s.size() / 4) + 1;
142    }
143
144    void writeGCOVString(StringRef s) {
145      uint32_t Len = lengthOfGCOVString(s);
146      write(Len);
147      writeBytes(s.data(), s.size());
148
149      // Write 1 to 4 bytes of NUL padding.
150      assert((unsigned)(4 - (s.size() % 4)) > 0);
151      assert((unsigned)(4 - (s.size() % 4)) <= 4);
152      writeBytes("\0\0\0\0", 4 - (s.size() % 4));
153    }
154
155    raw_ostream *os;
156  };
157  const char *GCOVRecord::LinesTag = "\0\0\x45\x01";
158  const char *GCOVRecord::FunctionTag = "\0\0\0\1";
159  const char *GCOVRecord::BlockTag = "\0\0\x41\x01";
160  const char *GCOVRecord::EdgeTag = "\0\0\x43\x01";
161
162  class GCOVFunction;
163  class GCOVBlock;
164
165  // Constructed only by requesting it from a GCOVBlock, this object stores a
166  // list of line numbers and a single filename, representing lines that belong
167  // to the block.
168  class GCOVLines : public GCOVRecord {
169   public:
170    void addLine(uint32_t Line) {
171      Lines.push_back(Line);
172    }
173
174    uint32_t length() {
175      // Here 2 = 1 for string length + 1 for '0' id#.
176      return lengthOfGCOVString(Filename) + 2 + Lines.size();
177    }
178
179    void writeOut() {
180      write(0);
181      writeGCOVString(Filename);
182      for (int i = 0, e = Lines.size(); i != e; ++i)
183        write(Lines[i]);
184    }
185
186    GCOVLines(StringRef F, raw_ostream *os)
187      : Filename(F) {
188      this->os = os;
189    }
190
191   private:
192    StringRef Filename;
193    SmallVector<uint32_t, 32> Lines;
194  };
195
196  // Represent a basic block in GCOV. Each block has a unique number in the
197  // function, number of lines belonging to each block, and a set of edges to
198  // other blocks.
199  class GCOVBlock : public GCOVRecord {
200   public:
201    GCOVLines &getFile(StringRef Filename) {
202      GCOVLines *&Lines = LinesByFile[Filename];
203      if (!Lines) {
204        Lines = new GCOVLines(Filename, os);
205      }
206      return *Lines;
207    }
208
209    void addEdge(GCOVBlock &Successor) {
210      OutEdges.push_back(&Successor);
211    }
212
213    void writeOut() {
214      uint32_t Len = 3;
215      for (StringMap<GCOVLines *>::iterator I = LinesByFile.begin(),
216               E = LinesByFile.end(); I != E; ++I) {
217        Len += I->second->length();
218      }
219
220      writeBytes(LinesTag, 4);
221      write(Len);
222      write(Number);
223      for (StringMap<GCOVLines *>::iterator I = LinesByFile.begin(),
224               E = LinesByFile.end(); I != E; ++I)
225        I->second->writeOut();
226      write(0);
227      write(0);
228    }
229
230    ~GCOVBlock() {
231      DeleteContainerSeconds(LinesByFile);
232    }
233
234   private:
235    friend class GCOVFunction;
236
237    GCOVBlock(uint32_t Number, raw_ostream *os)
238        : Number(Number) {
239      this->os = os;
240    }
241
242    uint32_t Number;
243    StringMap<GCOVLines *> LinesByFile;
244    SmallVector<GCOVBlock *, 4> OutEdges;
245  };
246
247  // A function has a unique identifier, a checksum (we leave as zero) and a
248  // set of blocks and a map of edges between blocks. This is the only GCOV
249  // object users can construct, the blocks and lines will be rooted here.
250  class GCOVFunction : public GCOVRecord {
251   public:
252    GCOVFunction(DISubprogram SP, raw_ostream *os,
253                 bool Use402Format, bool UseExtraChecksum) {
254      this->os = os;
255
256      Function *F = SP.getFunction();
257      DEBUG(dbgs() << "Function: " << F->getName() << "\n");
258      uint32_t i = 0;
259      for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
260        Blocks[BB] = new GCOVBlock(i++, os);
261      }
262      ReturnBlock = new GCOVBlock(i++, os);
263
264      writeBytes(FunctionTag, 4);
265      uint32_t BlockLen = 1 + 1 + 1 + lengthOfGCOVString(SP.getName()) +
266          1 + lengthOfGCOVString(SP.getFilename()) + 1;
267      if (UseExtraChecksum)
268        ++BlockLen;
269      write(BlockLen);
270      uint32_t Ident = reinterpret_cast<intptr_t>((MDNode*)SP);
271      write(Ident);
272      write(0);  // lineno checksum
273      if (UseExtraChecksum)
274        write(0);  // cfg checksum
275      writeGCOVString(SP.getName());
276      writeGCOVString(SP.getFilename());
277      write(SP.getLineNumber());
278    }
279
280    ~GCOVFunction() {
281      DeleteContainerSeconds(Blocks);
282      delete ReturnBlock;
283    }
284
285    GCOVBlock &getBlock(BasicBlock *BB) {
286      return *Blocks[BB];
287    }
288
289    GCOVBlock &getReturnBlock() {
290      return *ReturnBlock;
291    }
292
293    void writeOut() {
294      // Emit count of blocks.
295      writeBytes(BlockTag, 4);
296      write(Blocks.size() + 1);
297      for (int i = 0, e = Blocks.size() + 1; i != e; ++i) {
298        write(0);  // No flags on our blocks.
299      }
300      DEBUG(dbgs() << Blocks.size() << " blocks.\n");
301
302      // Emit edges between blocks.
303      for (DenseMap<BasicBlock *, GCOVBlock *>::iterator I = Blocks.begin(),
304               E = Blocks.end(); I != E; ++I) {
305        GCOVBlock &Block = *I->second;
306        if (Block.OutEdges.empty()) continue;
307
308        writeBytes(EdgeTag, 4);
309        write(Block.OutEdges.size() * 2 + 1);
310        write(Block.Number);
311        for (int i = 0, e = Block.OutEdges.size(); i != e; ++i) {
312          DEBUG(dbgs() << Block.Number << " -> " << Block.OutEdges[i]->Number
313                       << "\n");
314          write(Block.OutEdges[i]->Number);
315          write(0);  // no flags
316        }
317      }
318
319      // Emit lines for each block.
320      for (DenseMap<BasicBlock *, GCOVBlock *>::iterator I = Blocks.begin(),
321               E = Blocks.end(); I != E; ++I) {
322        I->second->writeOut();
323      }
324    }
325
326   private:
327    DenseMap<BasicBlock *, GCOVBlock *> Blocks;
328    GCOVBlock *ReturnBlock;
329  };
330}
331
332std::string GCOVProfiler::mangleName(DICompileUnit CU, const char *NewStem) {
333  if (NamedMDNode *GCov = M->getNamedMetadata("llvm.gcov")) {
334    for (int i = 0, e = GCov->getNumOperands(); i != e; ++i) {
335      MDNode *N = GCov->getOperand(i);
336      if (N->getNumOperands() != 2) continue;
337      MDString *GCovFile = dyn_cast<MDString>(N->getOperand(0));
338      MDNode *CompileUnit = dyn_cast<MDNode>(N->getOperand(1));
339      if (!GCovFile || !CompileUnit) continue;
340      if (CompileUnit == CU) {
341        SmallString<128> Filename = GCovFile->getString();
342        sys::path::replace_extension(Filename, NewStem);
343        return Filename.str();
344      }
345    }
346  }
347
348  SmallString<128> Filename = CU.getFilename();
349  sys::path::replace_extension(Filename, NewStem);
350  return sys::path::filename(Filename.str());
351}
352
353bool GCOVProfiler::runOnModule(Module &M) {
354  this->M = &M;
355  Ctx = &M.getContext();
356
357  if (EmitNotes) emitGCNO();
358  if (EmitData) return emitProfileArcs();
359  return false;
360}
361
362void GCOVProfiler::emitGCNO() {
363  NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
364  if (!CU_Nodes) return;
365
366  for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
367    // Each compile unit gets its own .gcno file. This means that whether we run
368    // this pass over the original .o's as they're produced, or run it after
369    // LTO, we'll generate the same .gcno files.
370
371    DICompileUnit CU(CU_Nodes->getOperand(i));
372    std::string ErrorInfo;
373    raw_fd_ostream out(mangleName(CU, "gcno").c_str(), ErrorInfo,
374                       raw_fd_ostream::F_Binary);
375    if (!Use402Format)
376      out.write("oncg*404MVLL", 12);
377    else
378      out.write("oncg*204MVLL", 12);
379
380    DIArray SPs = CU.getSubprograms();
381    for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i) {
382      DISubprogram SP(SPs.getElement(i));
383      if (!SP.Verify()) continue;
384
385      Function *F = SP.getFunction();
386      if (!F) continue;
387      GCOVFunction Func(SP, &out, Use402Format, UseExtraChecksum);
388
389      for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
390        GCOVBlock &Block = Func.getBlock(BB);
391        TerminatorInst *TI = BB->getTerminator();
392        if (int successors = TI->getNumSuccessors()) {
393          for (int i = 0; i != successors; ++i) {
394            Block.addEdge(Func.getBlock(TI->getSuccessor(i)));
395          }
396        } else if (isa<ReturnInst>(TI)) {
397          Block.addEdge(Func.getReturnBlock());
398        }
399
400        uint32_t Line = 0;
401        for (BasicBlock::iterator I = BB->begin(), IE = BB->end();
402             I != IE; ++I) {
403          const DebugLoc &Loc = I->getDebugLoc();
404          if (Loc.isUnknown()) continue;
405          if (Line == Loc.getLine()) continue;
406          Line = Loc.getLine();
407          if (SP != getDISubprogram(Loc.getScope(*Ctx))) continue;
408
409          GCOVLines &Lines = Block.getFile(SP.getFilename());
410          Lines.addLine(Loc.getLine());
411        }
412      }
413      Func.writeOut();
414    }
415    out.write("\0\0\0\0\0\0\0\0", 8);  // EOF
416    out.close();
417  }
418}
419
420bool GCOVProfiler::emitProfileArcs() {
421  NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
422  if (!CU_Nodes) return false;
423
424  bool Result = false;
425  bool InsertIndCounterIncrCode = false;
426  for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
427    DICompileUnit CU(CU_Nodes->getOperand(i));
428    DIArray SPs = CU.getSubprograms();
429    SmallVector<std::pair<GlobalVariable *, MDNode *>, 8> CountersBySP;
430    for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i) {
431      DISubprogram SP(SPs.getElement(i));
432      if (!SP.Verify()) continue;
433      Function *F = SP.getFunction();
434      if (!F) continue;
435      if (!Result) Result = true;
436      unsigned Edges = 0;
437      for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
438        TerminatorInst *TI = BB->getTerminator();
439        if (isa<ReturnInst>(TI))
440          ++Edges;
441        else
442          Edges += TI->getNumSuccessors();
443      }
444
445      ArrayType *CounterTy =
446        ArrayType::get(Type::getInt64Ty(*Ctx), Edges);
447      GlobalVariable *Counters =
448        new GlobalVariable(*M, CounterTy, false,
449                           GlobalValue::InternalLinkage,
450                           Constant::getNullValue(CounterTy),
451                           "__llvm_gcov_ctr");
452      CountersBySP.push_back(std::make_pair(Counters, (MDNode*)SP));
453
454      UniqueVector<BasicBlock *> ComplexEdgePreds;
455      UniqueVector<BasicBlock *> ComplexEdgeSuccs;
456
457      unsigned Edge = 0;
458      for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
459        TerminatorInst *TI = BB->getTerminator();
460        int Successors = isa<ReturnInst>(TI) ? 1 : TI->getNumSuccessors();
461        if (Successors) {
462          IRBuilder<> Builder(TI);
463
464          if (Successors == 1) {
465            Value *Counter = Builder.CreateConstInBoundsGEP2_64(Counters, 0,
466                                                                Edge);
467            Value *Count = Builder.CreateLoad(Counter);
468            Count = Builder.CreateAdd(Count,
469                                      ConstantInt::get(Type::getInt64Ty(*Ctx),1));
470            Builder.CreateStore(Count, Counter);
471          } else if (BranchInst *BI = dyn_cast<BranchInst>(TI)) {
472            Value *Sel = Builder.CreateSelect(
473              BI->getCondition(),
474              ConstantInt::get(Type::getInt64Ty(*Ctx), Edge),
475              ConstantInt::get(Type::getInt64Ty(*Ctx), Edge + 1));
476            SmallVector<Value *, 2> Idx;
477            Idx.push_back(Constant::getNullValue(Type::getInt64Ty(*Ctx)));
478            Idx.push_back(Sel);
479            Value *Counter = Builder.CreateInBoundsGEP(Counters, Idx);
480            Value *Count = Builder.CreateLoad(Counter);
481            Count = Builder.CreateAdd(Count,
482                                      ConstantInt::get(Type::getInt64Ty(*Ctx),1));
483            Builder.CreateStore(Count, Counter);
484          } else {
485            ComplexEdgePreds.insert(BB);
486            for (int i = 0; i != Successors; ++i)
487              ComplexEdgeSuccs.insert(TI->getSuccessor(i));
488          }
489          Edge += Successors;
490        }
491      }
492
493      if (!ComplexEdgePreds.empty()) {
494        GlobalVariable *EdgeTable =
495          buildEdgeLookupTable(F, Counters,
496                               ComplexEdgePreds, ComplexEdgeSuccs);
497        GlobalVariable *EdgeState = getEdgeStateValue();
498
499        Type *Int32Ty = Type::getInt32Ty(*Ctx);
500        for (int i = 0, e = ComplexEdgePreds.size(); i != e; ++i) {
501          IRBuilder<> Builder(ComplexEdgePreds[i+1]->getTerminator());
502          Builder.CreateStore(ConstantInt::get(Int32Ty, i), EdgeState);
503        }
504        for (int i = 0, e = ComplexEdgeSuccs.size(); i != e; ++i) {
505          // call runtime to perform increment
506          BasicBlock::iterator InsertPt =
507            ComplexEdgeSuccs[i+1]->getFirstInsertionPt();
508          IRBuilder<> Builder(InsertPt);
509          Value *CounterPtrArray =
510            Builder.CreateConstInBoundsGEP2_64(EdgeTable, 0,
511                                               i * ComplexEdgePreds.size());
512
513          // Build code to increment the counter.
514          InsertIndCounterIncrCode = true;
515          Builder.CreateCall2(getIncrementIndirectCounterFunc(),
516                              EdgeState, CounterPtrArray);
517        }
518      }
519    }
520
521    insertCounterWriteout(CountersBySP);
522    insertFlush(CountersBySP);
523  }
524
525  if (InsertIndCounterIncrCode)
526    insertIndirectCounterIncrement();
527
528  return Result;
529}
530
531// All edges with successors that aren't branches are "complex", because it
532// requires complex logic to pick which counter to update.
533GlobalVariable *GCOVProfiler::buildEdgeLookupTable(
534    Function *F,
535    GlobalVariable *Counters,
536    const UniqueVector<BasicBlock *> &Preds,
537    const UniqueVector<BasicBlock *> &Succs) {
538  // TODO: support invoke, threads. We rely on the fact that nothing can modify
539  // the whole-Module pred edge# between the time we set it and the time we next
540  // read it. Threads and invoke make this untrue.
541
542  // emit [(succs * preds) x i64*], logically [succ x [pred x i64*]].
543  size_t TableSize = Succs.size() * Preds.size();
544  Type *Int64PtrTy = Type::getInt64PtrTy(*Ctx);
545  ArrayType *EdgeTableTy = ArrayType::get(Int64PtrTy, TableSize);
546
547  OwningArrayPtr<Constant *> EdgeTable(new Constant*[TableSize]);
548  Constant *NullValue = Constant::getNullValue(Int64PtrTy);
549  for (size_t i = 0; i != TableSize; ++i)
550    EdgeTable[i] = NullValue;
551
552  unsigned Edge = 0;
553  for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
554    TerminatorInst *TI = BB->getTerminator();
555    int Successors = isa<ReturnInst>(TI) ? 1 : TI->getNumSuccessors();
556    if (Successors > 1 && !isa<BranchInst>(TI) && !isa<ReturnInst>(TI)) {
557      for (int i = 0; i != Successors; ++i) {
558        BasicBlock *Succ = TI->getSuccessor(i);
559        IRBuilder<> builder(Succ);
560        Value *Counter = builder.CreateConstInBoundsGEP2_64(Counters, 0,
561                                                            Edge + i);
562        EdgeTable[((Succs.idFor(Succ)-1) * Preds.size()) +
563                  (Preds.idFor(BB)-1)] = cast<Constant>(Counter);
564      }
565    }
566    Edge += Successors;
567  }
568
569  ArrayRef<Constant*> V(&EdgeTable[0], TableSize);
570  GlobalVariable *EdgeTableGV =
571      new GlobalVariable(
572          *M, EdgeTableTy, true, GlobalValue::InternalLinkage,
573          ConstantArray::get(EdgeTableTy, V),
574          "__llvm_gcda_edge_table");
575  EdgeTableGV->setUnnamedAddr(true);
576  return EdgeTableGV;
577}
578
579Constant *GCOVProfiler::getStartFileFunc() {
580  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx),
581                                              Type::getInt8PtrTy(*Ctx), false);
582  return M->getOrInsertFunction("llvm_gcda_start_file", FTy);
583}
584
585Constant *GCOVProfiler::getIncrementIndirectCounterFunc() {
586  Type *Int32Ty = Type::getInt32Ty(*Ctx);
587  Type *Int64Ty = Type::getInt64Ty(*Ctx);
588  Type *Args[] = {
589    Int32Ty->getPointerTo(),                // uint32_t *predecessor
590    Int64Ty->getPointerTo()->getPointerTo() // uint64_t **counters
591  };
592  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false);
593  return M->getOrInsertFunction("__llvm_gcov_indirect_counter_increment", FTy);
594}
595
596Constant *GCOVProfiler::getEmitFunctionFunc() {
597  Type *Args[2] = {
598    Type::getInt32Ty(*Ctx),    // uint32_t ident
599    Type::getInt8PtrTy(*Ctx),  // const char *function_name
600  };
601  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false);
602  return M->getOrInsertFunction("llvm_gcda_emit_function", FTy);
603}
604
605Constant *GCOVProfiler::getEmitArcsFunc() {
606  Type *Args[] = {
607    Type::getInt32Ty(*Ctx),     // uint32_t num_counters
608    Type::getInt64PtrTy(*Ctx),  // uint64_t *counters
609  };
610  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx),
611                                              Args, false);
612  return M->getOrInsertFunction("llvm_gcda_emit_arcs", FTy);
613}
614
615Constant *GCOVProfiler::getEndFileFunc() {
616  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
617  return M->getOrInsertFunction("llvm_gcda_end_file", FTy);
618}
619
620GlobalVariable *GCOVProfiler::getEdgeStateValue() {
621  GlobalVariable *GV = M->getGlobalVariable("__llvm_gcov_global_state_pred");
622  if (!GV) {
623    GV = new GlobalVariable(*M, Type::getInt32Ty(*Ctx), false,
624                            GlobalValue::InternalLinkage,
625                            ConstantInt::get(Type::getInt32Ty(*Ctx),
626                                             0xffffffff),
627                            "__llvm_gcov_global_state_pred");
628    GV->setUnnamedAddr(true);
629  }
630  return GV;
631}
632
633void GCOVProfiler::insertCounterWriteout(
634    ArrayRef<std::pair<GlobalVariable *, MDNode *> > CountersBySP) {
635  FunctionType *WriteoutFTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
636  Function *WriteoutF = M->getFunction("__llvm_gcov_writeout");
637  if (!WriteoutF)
638    WriteoutF = Function::Create(WriteoutFTy, GlobalValue::InternalLinkage,
639                                 "__llvm_gcov_writeout", M);
640  WriteoutF->setUnnamedAddr(true);
641
642  BasicBlock *BB = BasicBlock::Create(*Ctx, "entry", WriteoutF);
643  IRBuilder<> Builder(BB);
644
645  Constant *StartFile = getStartFileFunc();
646  Constant *EmitFunction = getEmitFunctionFunc();
647  Constant *EmitArcs = getEmitArcsFunc();
648  Constant *EndFile = getEndFileFunc();
649
650  NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
651  if (CU_Nodes) {
652    for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
653      DICompileUnit CU(CU_Nodes->getOperand(i));
654      std::string FilenameGcda = mangleName(CU, "gcda");
655      Builder.CreateCall(StartFile,
656                         Builder.CreateGlobalStringPtr(FilenameGcda));
657      for (ArrayRef<std::pair<GlobalVariable *, MDNode *> >::iterator
658             I = CountersBySP.begin(), E = CountersBySP.end();
659           I != E; ++I) {
660        DISubprogram SP(I->second);
661        intptr_t ident = reinterpret_cast<intptr_t>(I->second);
662        Builder.CreateCall2(EmitFunction,
663                            ConstantInt::get(Type::getInt32Ty(*Ctx), ident),
664                            Builder.CreateGlobalStringPtr(SP.getName()));
665
666        GlobalVariable *GV = I->first;
667        unsigned Arcs =
668          cast<ArrayType>(GV->getType()->getElementType())->getNumElements();
669        Builder.CreateCall2(EmitArcs,
670                            ConstantInt::get(Type::getInt32Ty(*Ctx), Arcs),
671                            Builder.CreateConstGEP2_64(GV, 0, 0));
672      }
673      Builder.CreateCall(EndFile);
674    }
675  }
676  Builder.CreateRetVoid();
677
678  // Create a small bit of code that registers the "__llvm_gcov_writeout"
679  // function to be executed at exit.
680  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
681  Function *F = Function::Create(FTy, GlobalValue::InternalLinkage,
682                                 "__llvm_gcov_init", M);
683  F->setUnnamedAddr(true);
684  F->setLinkage(GlobalValue::InternalLinkage);
685  F->addFnAttr(Attributes::NoInline);
686
687  BB = BasicBlock::Create(*Ctx, "entry", F);
688  Builder.SetInsertPoint(BB);
689
690  FTy = FunctionType::get(Type::getInt32Ty(*Ctx),
691                          PointerType::get(FTy, 0), false);
692  Constant *AtExitFn = M->getOrInsertFunction("atexit", FTy);
693  Builder.CreateCall(AtExitFn, WriteoutF);
694  Builder.CreateRetVoid();
695
696  appendToGlobalCtors(*M, F, 0);
697}
698
699void GCOVProfiler::insertIndirectCounterIncrement() {
700  Function *Fn =
701    cast<Function>(GCOVProfiler::getIncrementIndirectCounterFunc());
702  Fn->setUnnamedAddr(true);
703  Fn->setLinkage(GlobalValue::InternalLinkage);
704  Fn->addFnAttr(Attributes::NoInline);
705
706  Type *Int32Ty = Type::getInt32Ty(*Ctx);
707  Type *Int64Ty = Type::getInt64Ty(*Ctx);
708  Constant *NegOne = ConstantInt::get(Int32Ty, 0xffffffff);
709
710  // Create basic blocks for function.
711  BasicBlock *BB = BasicBlock::Create(*Ctx, "entry", Fn);
712  IRBuilder<> Builder(BB);
713
714  BasicBlock *PredNotNegOne = BasicBlock::Create(*Ctx, "", Fn);
715  BasicBlock *CounterEnd = BasicBlock::Create(*Ctx, "", Fn);
716  BasicBlock *Exit = BasicBlock::Create(*Ctx, "exit", Fn);
717
718  // uint32_t pred = *predecessor;
719  // if (pred == 0xffffffff) return;
720  Argument *Arg = Fn->arg_begin();
721  Arg->setName("predecessor");
722  Value *Pred = Builder.CreateLoad(Arg, "pred");
723  Value *Cond = Builder.CreateICmpEQ(Pred, NegOne);
724  BranchInst::Create(Exit, PredNotNegOne, Cond, BB);
725
726  Builder.SetInsertPoint(PredNotNegOne);
727
728  // uint64_t *counter = counters[pred];
729  // if (!counter) return;
730  Value *ZExtPred = Builder.CreateZExt(Pred, Int64Ty);
731  Arg = llvm::next(Fn->arg_begin());
732  Arg->setName("counters");
733  Value *GEP = Builder.CreateGEP(Arg, ZExtPred);
734  Value *Counter = Builder.CreateLoad(GEP, "counter");
735  Cond = Builder.CreateICmpEQ(Counter,
736                              Constant::getNullValue(Int64Ty->getPointerTo()));
737  Builder.CreateCondBr(Cond, Exit, CounterEnd);
738
739  // ++*counter;
740  Builder.SetInsertPoint(CounterEnd);
741  Value *Add = Builder.CreateAdd(Builder.CreateLoad(Counter),
742                                 ConstantInt::get(Int64Ty, 1));
743  Builder.CreateStore(Add, Counter);
744  Builder.CreateBr(Exit);
745
746  // Fill in the exit block.
747  Builder.SetInsertPoint(Exit);
748  Builder.CreateRetVoid();
749}
750
751void GCOVProfiler::
752insertFlush(ArrayRef<std::pair<GlobalVariable*, MDNode*> > CountersBySP) {
753  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
754  Function *FlushF = M->getFunction("__gcov_flush");
755  if (!FlushF)
756    FlushF = Function::Create(FTy, GlobalValue::InternalLinkage,
757                              "__gcov_flush", M);
758  else
759    FlushF->setLinkage(GlobalValue::InternalLinkage);
760  FlushF->setUnnamedAddr(true);
761
762  BasicBlock *Entry = BasicBlock::Create(*Ctx, "entry", FlushF);
763
764  // Write out the current counters.
765  Constant *WriteoutF = M->getFunction("__llvm_gcov_writeout");
766  assert(WriteoutF && "Need to create the writeout function first!");
767
768  IRBuilder<> Builder(Entry);
769  Builder.CreateCall(WriteoutF);
770
771  // Zero out the counters.
772  for (ArrayRef<std::pair<GlobalVariable *, MDNode *> >::iterator
773         I = CountersBySP.begin(), E = CountersBySP.end();
774       I != E; ++I) {
775    GlobalVariable *GV = I->first;
776    Constant *Null = Constant::getNullValue(GV->getType()->getElementType());
777    Builder.CreateStore(Null, GV);
778  }
779
780  Type *RetTy = FlushF->getReturnType();
781  if (RetTy == Type::getVoidTy(*Ctx))
782    Builder.CreateRetVoid();
783  else if (RetTy->isIntegerTy())
784    // Used if __gcov_flush was implicitly declared.
785    Builder.CreateRet(ConstantInt::get(RetTy, 0));
786  else
787    report_fatal_error("invalid return type for __gcov_flush");
788}
789