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/CommandLine.h"
33#include "llvm/Support/Debug.h"
34#include "llvm/Support/DebugLoc.h"
35#include "llvm/Support/InstIterator.h"
36#include "llvm/Support/PathV2.h"
37#include "llvm/Support/raw_ostream.h"
38#include "llvm/Transforms/Utils/ModuleUtils.h"
39#include <string>
40#include <utility>
41using namespace llvm;
42
43static cl::opt<std::string>
44DefaultGCOVVersion("default-gcov-version", cl::init("402*"), cl::Hidden,
45                   cl::ValueRequired);
46
47GCOVOptions GCOVOptions::getDefault() {
48  GCOVOptions Options;
49  Options.EmitNotes = true;
50  Options.EmitData = true;
51  Options.UseCfgChecksum = false;
52  Options.NoRedZone = false;
53  Options.FunctionNamesInData = true;
54
55  if (DefaultGCOVVersion.size() != 4) {
56    llvm::report_fatal_error(std::string("Invalid -default-gcov-version: ") +
57                             DefaultGCOVVersion);
58  }
59  memcpy(Options.Version, DefaultGCOVVersion.c_str(), 4);
60  return Options;
61}
62
63namespace {
64  class GCOVProfiler : public ModulePass {
65  public:
66    static char ID;
67    GCOVProfiler() : ModulePass(ID), Options(GCOVOptions::getDefault()) {
68      ReversedVersion[0] = Options.Version[3];
69      ReversedVersion[1] = Options.Version[2];
70      ReversedVersion[2] = Options.Version[1];
71      ReversedVersion[3] = Options.Version[0];
72      ReversedVersion[4] = '\0';
73      initializeGCOVProfilerPass(*PassRegistry::getPassRegistry());
74    }
75    GCOVProfiler(const GCOVOptions &Options) : ModulePass(ID), Options(Options){
76      assert((Options.EmitNotes || Options.EmitData) &&
77             "GCOVProfiler asked to do nothing?");
78      ReversedVersion[0] = Options.Version[3];
79      ReversedVersion[1] = Options.Version[2];
80      ReversedVersion[2] = Options.Version[1];
81      ReversedVersion[3] = Options.Version[0];
82      ReversedVersion[4] = '\0';
83      initializeGCOVProfilerPass(*PassRegistry::getPassRegistry());
84    }
85    virtual const char *getPassName() const {
86      return "GCOV Profiler";
87    }
88
89  private:
90    bool runOnModule(Module &M);
91
92    // Create the .gcno files for the Module based on DebugInfo.
93    void emitProfileNotes();
94
95    // Modify the program to track transitions along edges and call into the
96    // profiling runtime to emit .gcda files when run.
97    bool emitProfileArcs();
98
99    // Get pointers to the functions in the runtime library.
100    Constant *getStartFileFunc();
101    Constant *getIncrementIndirectCounterFunc();
102    Constant *getEmitFunctionFunc();
103    Constant *getEmitArcsFunc();
104    Constant *getDeleteFlushFunctionListFunc();
105    Constant *getEndFileFunc();
106
107    // Create or retrieve an i32 state value that is used to represent the
108    // pred block number for certain non-trivial edges.
109    GlobalVariable *getEdgeStateValue();
110
111    // Produce a table of pointers to counters, by predecessor and successor
112    // block number.
113    GlobalVariable *buildEdgeLookupTable(Function *F,
114                                         GlobalVariable *Counter,
115                                         const UniqueVector<BasicBlock *>&Preds,
116                                         const UniqueVector<BasicBlock*>&Succs);
117
118    // Add the function to write out all our counters to the global destructor
119    // list.
120    Function *insertCounterWriteout(ArrayRef<std::pair<GlobalVariable*,
121                                                       MDNode*> >);
122    Function *insertFlush(ArrayRef<std::pair<GlobalVariable*, MDNode*> >);
123    void insertIndirectCounterIncrement();
124
125    std::string mangleName(DICompileUnit CU, const char *NewStem);
126
127    GCOVOptions Options;
128
129    // Reversed, NUL-terminated copy of Options.Version.
130    char ReversedVersion[5];
131
132    Module *M;
133    LLVMContext *Ctx;
134  };
135}
136
137char GCOVProfiler::ID = 0;
138INITIALIZE_PASS(GCOVProfiler, "insert-gcov-profiling",
139                "Insert instrumentation for GCOV profiling", false, false)
140
141ModulePass *llvm::createGCOVProfilerPass(const GCOVOptions &Options) {
142  return new GCOVProfiler(Options);
143}
144
145namespace {
146  class GCOVRecord {
147   protected:
148    static const char *LinesTag;
149    static const char *FunctionTag;
150    static const char *BlockTag;
151    static const char *EdgeTag;
152
153    GCOVRecord() {}
154
155    void writeBytes(const char *Bytes, int Size) {
156      os->write(Bytes, Size);
157    }
158
159    void write(uint32_t i) {
160      writeBytes(reinterpret_cast<char*>(&i), 4);
161    }
162
163    // Returns the length measured in 4-byte blocks that will be used to
164    // represent this string in a GCOV file
165    unsigned lengthOfGCOVString(StringRef s) {
166      // A GCOV string is a length, followed by a NUL, then between 0 and 3 NULs
167      // padding out to the next 4-byte word. The length is measured in 4-byte
168      // words including padding, not bytes of actual string.
169      return (s.size() / 4) + 1;
170    }
171
172    void writeGCOVString(StringRef s) {
173      uint32_t Len = lengthOfGCOVString(s);
174      write(Len);
175      writeBytes(s.data(), s.size());
176
177      // Write 1 to 4 bytes of NUL padding.
178      assert((unsigned)(4 - (s.size() % 4)) > 0);
179      assert((unsigned)(4 - (s.size() % 4)) <= 4);
180      writeBytes("\0\0\0\0", 4 - (s.size() % 4));
181    }
182
183    raw_ostream *os;
184  };
185  const char *GCOVRecord::LinesTag = "\0\0\x45\x01";
186  const char *GCOVRecord::FunctionTag = "\0\0\0\1";
187  const char *GCOVRecord::BlockTag = "\0\0\x41\x01";
188  const char *GCOVRecord::EdgeTag = "\0\0\x43\x01";
189
190  class GCOVFunction;
191  class GCOVBlock;
192
193  // Constructed only by requesting it from a GCOVBlock, this object stores a
194  // list of line numbers and a single filename, representing lines that belong
195  // to the block.
196  class GCOVLines : public GCOVRecord {
197   public:
198    void addLine(uint32_t Line) {
199      Lines.push_back(Line);
200    }
201
202    uint32_t length() {
203      // Here 2 = 1 for string length + 1 for '0' id#.
204      return lengthOfGCOVString(Filename) + 2 + Lines.size();
205    }
206
207    void writeOut() {
208      write(0);
209      writeGCOVString(Filename);
210      for (int i = 0, e = Lines.size(); i != e; ++i)
211        write(Lines[i]);
212    }
213
214    GCOVLines(StringRef F, raw_ostream *os)
215      : Filename(F) {
216      this->os = os;
217    }
218
219   private:
220    StringRef Filename;
221    SmallVector<uint32_t, 32> Lines;
222  };
223
224  // Represent a basic block in GCOV. Each block has a unique number in the
225  // function, number of lines belonging to each block, and a set of edges to
226  // other blocks.
227  class GCOVBlock : public GCOVRecord {
228   public:
229    GCOVLines &getFile(StringRef Filename) {
230      GCOVLines *&Lines = LinesByFile[Filename];
231      if (!Lines) {
232        Lines = new GCOVLines(Filename, os);
233      }
234      return *Lines;
235    }
236
237    void addEdge(GCOVBlock &Successor) {
238      OutEdges.push_back(&Successor);
239    }
240
241    void writeOut() {
242      uint32_t Len = 3;
243      for (StringMap<GCOVLines *>::iterator I = LinesByFile.begin(),
244               E = LinesByFile.end(); I != E; ++I) {
245        Len += I->second->length();
246      }
247
248      writeBytes(LinesTag, 4);
249      write(Len);
250      write(Number);
251      for (StringMap<GCOVLines *>::iterator I = LinesByFile.begin(),
252               E = LinesByFile.end(); I != E; ++I)
253        I->second->writeOut();
254      write(0);
255      write(0);
256    }
257
258    ~GCOVBlock() {
259      DeleteContainerSeconds(LinesByFile);
260    }
261
262   private:
263    friend class GCOVFunction;
264
265    GCOVBlock(uint32_t Number, raw_ostream *os)
266        : Number(Number) {
267      this->os = os;
268    }
269
270    uint32_t Number;
271    StringMap<GCOVLines *> LinesByFile;
272    SmallVector<GCOVBlock *, 4> OutEdges;
273  };
274
275  // A function has a unique identifier, a checksum (we leave as zero) and a
276  // set of blocks and a map of edges between blocks. This is the only GCOV
277  // object users can construct, the blocks and lines will be rooted here.
278  class GCOVFunction : public GCOVRecord {
279   public:
280    GCOVFunction(DISubprogram SP, raw_ostream *os, uint32_t Ident,
281                 bool UseCfgChecksum) {
282      this->os = os;
283
284      Function *F = SP.getFunction();
285      DEBUG(dbgs() << "Function: " << F->getName() << "\n");
286      uint32_t i = 0;
287      for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
288        Blocks[BB] = new GCOVBlock(i++, os);
289      }
290      ReturnBlock = new GCOVBlock(i++, os);
291
292      writeBytes(FunctionTag, 4);
293      uint32_t BlockLen = 1 + 1 + 1 + lengthOfGCOVString(SP.getName()) +
294          1 + lengthOfGCOVString(SP.getFilename()) + 1;
295      if (UseCfgChecksum)
296        ++BlockLen;
297      write(BlockLen);
298      write(Ident);
299      write(0);  // lineno checksum
300      if (UseCfgChecksum)
301        write(0);  // cfg checksum
302      writeGCOVString(SP.getName());
303      writeGCOVString(SP.getFilename());
304      write(SP.getLineNumber());
305    }
306
307    ~GCOVFunction() {
308      DeleteContainerSeconds(Blocks);
309      delete ReturnBlock;
310    }
311
312    GCOVBlock &getBlock(BasicBlock *BB) {
313      return *Blocks[BB];
314    }
315
316    GCOVBlock &getReturnBlock() {
317      return *ReturnBlock;
318    }
319
320    void writeOut() {
321      // Emit count of blocks.
322      writeBytes(BlockTag, 4);
323      write(Blocks.size() + 1);
324      for (int i = 0, e = Blocks.size() + 1; i != e; ++i) {
325        write(0);  // No flags on our blocks.
326      }
327      DEBUG(dbgs() << Blocks.size() << " blocks.\n");
328
329      // Emit edges between blocks.
330      for (DenseMap<BasicBlock *, GCOVBlock *>::iterator I = Blocks.begin(),
331               E = Blocks.end(); I != E; ++I) {
332        GCOVBlock &Block = *I->second;
333        if (Block.OutEdges.empty()) continue;
334
335        writeBytes(EdgeTag, 4);
336        write(Block.OutEdges.size() * 2 + 1);
337        write(Block.Number);
338        for (int i = 0, e = Block.OutEdges.size(); i != e; ++i) {
339          DEBUG(dbgs() << Block.Number << " -> " << Block.OutEdges[i]->Number
340                       << "\n");
341          write(Block.OutEdges[i]->Number);
342          write(0);  // no flags
343        }
344      }
345
346      // Emit lines for each block.
347      for (DenseMap<BasicBlock *, GCOVBlock *>::iterator I = Blocks.begin(),
348               E = Blocks.end(); I != E; ++I) {
349        I->second->writeOut();
350      }
351    }
352
353   private:
354    DenseMap<BasicBlock *, GCOVBlock *> Blocks;
355    GCOVBlock *ReturnBlock;
356  };
357}
358
359std::string GCOVProfiler::mangleName(DICompileUnit CU, const char *NewStem) {
360  if (NamedMDNode *GCov = M->getNamedMetadata("llvm.gcov")) {
361    for (int i = 0, e = GCov->getNumOperands(); i != e; ++i) {
362      MDNode *N = GCov->getOperand(i);
363      if (N->getNumOperands() != 2) continue;
364      MDString *GCovFile = dyn_cast<MDString>(N->getOperand(0));
365      MDNode *CompileUnit = dyn_cast<MDNode>(N->getOperand(1));
366      if (!GCovFile || !CompileUnit) continue;
367      if (CompileUnit == CU) {
368        SmallString<128> Filename = GCovFile->getString();
369        sys::path::replace_extension(Filename, NewStem);
370        return Filename.str();
371      }
372    }
373  }
374
375  SmallString<128> Filename = CU.getFilename();
376  sys::path::replace_extension(Filename, NewStem);
377  return sys::path::filename(Filename.str());
378}
379
380bool GCOVProfiler::runOnModule(Module &M) {
381  this->M = &M;
382  Ctx = &M.getContext();
383
384  if (Options.EmitNotes) emitProfileNotes();
385  if (Options.EmitData) return emitProfileArcs();
386  return false;
387}
388
389void GCOVProfiler::emitProfileNotes() {
390  NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
391  if (!CU_Nodes) return;
392
393  for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
394    // Each compile unit gets its own .gcno file. This means that whether we run
395    // this pass over the original .o's as they're produced, or run it after
396    // LTO, we'll generate the same .gcno files.
397
398    DICompileUnit CU(CU_Nodes->getOperand(i));
399    std::string ErrorInfo;
400    raw_fd_ostream out(mangleName(CU, "gcno").c_str(), ErrorInfo,
401                       raw_fd_ostream::F_Binary);
402    out.write("oncg", 4);
403    out.write(ReversedVersion, 4);
404    out.write("MVLL", 4);
405
406    DIArray SPs = CU.getSubprograms();
407    for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i) {
408      DISubprogram SP(SPs.getElement(i));
409      if (!SP.Verify()) continue;
410
411      Function *F = SP.getFunction();
412      if (!F) continue;
413      GCOVFunction Func(SP, &out, i, Options.UseCfgChecksum);
414
415      for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
416        GCOVBlock &Block = Func.getBlock(BB);
417        TerminatorInst *TI = BB->getTerminator();
418        if (int successors = TI->getNumSuccessors()) {
419          for (int i = 0; i != successors; ++i) {
420            Block.addEdge(Func.getBlock(TI->getSuccessor(i)));
421          }
422        } else if (isa<ReturnInst>(TI)) {
423          Block.addEdge(Func.getReturnBlock());
424        }
425
426        uint32_t Line = 0;
427        for (BasicBlock::iterator I = BB->begin(), IE = BB->end();
428             I != IE; ++I) {
429          const DebugLoc &Loc = I->getDebugLoc();
430          if (Loc.isUnknown()) continue;
431          if (Line == Loc.getLine()) continue;
432          Line = Loc.getLine();
433          if (SP != getDISubprogram(Loc.getScope(*Ctx))) continue;
434
435          GCOVLines &Lines = Block.getFile(SP.getFilename());
436          Lines.addLine(Loc.getLine());
437        }
438      }
439      Func.writeOut();
440    }
441    out.write("\0\0\0\0\0\0\0\0", 8);  // EOF
442    out.close();
443  }
444}
445
446bool GCOVProfiler::emitProfileArcs() {
447  NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
448  if (!CU_Nodes) return false;
449
450  bool Result = false;
451  bool InsertIndCounterIncrCode = false;
452  for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
453    DICompileUnit CU(CU_Nodes->getOperand(i));
454    DIArray SPs = CU.getSubprograms();
455    SmallVector<std::pair<GlobalVariable *, MDNode *>, 8> CountersBySP;
456    for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i) {
457      DISubprogram SP(SPs.getElement(i));
458      if (!SP.Verify()) continue;
459      Function *F = SP.getFunction();
460      if (!F) continue;
461      if (!Result) Result = true;
462      unsigned Edges = 0;
463      for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
464        TerminatorInst *TI = BB->getTerminator();
465        if (isa<ReturnInst>(TI))
466          ++Edges;
467        else
468          Edges += TI->getNumSuccessors();
469      }
470
471      ArrayType *CounterTy =
472        ArrayType::get(Type::getInt64Ty(*Ctx), Edges);
473      GlobalVariable *Counters =
474        new GlobalVariable(*M, CounterTy, false,
475                           GlobalValue::InternalLinkage,
476                           Constant::getNullValue(CounterTy),
477                           "__llvm_gcov_ctr");
478      CountersBySP.push_back(std::make_pair(Counters, (MDNode*)SP));
479
480      UniqueVector<BasicBlock *> ComplexEdgePreds;
481      UniqueVector<BasicBlock *> ComplexEdgeSuccs;
482
483      unsigned Edge = 0;
484      for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
485        TerminatorInst *TI = BB->getTerminator();
486        int Successors = isa<ReturnInst>(TI) ? 1 : TI->getNumSuccessors();
487        if (Successors) {
488          IRBuilder<> Builder(TI);
489
490          if (Successors == 1) {
491            Value *Counter = Builder.CreateConstInBoundsGEP2_64(Counters, 0,
492                                                                Edge);
493            Value *Count = Builder.CreateLoad(Counter);
494            Count = Builder.CreateAdd(Count, Builder.getInt64(1));
495            Builder.CreateStore(Count, Counter);
496          } else if (BranchInst *BI = dyn_cast<BranchInst>(TI)) {
497            Value *Sel = Builder.CreateSelect(BI->getCondition(),
498                                              Builder.getInt64(Edge),
499                                              Builder.getInt64(Edge + 1));
500            SmallVector<Value *, 2> Idx;
501            Idx.push_back(Builder.getInt64(0));
502            Idx.push_back(Sel);
503            Value *Counter = Builder.CreateInBoundsGEP(Counters, Idx);
504            Value *Count = Builder.CreateLoad(Counter);
505            Count = Builder.CreateAdd(Count, Builder.getInt64(1));
506            Builder.CreateStore(Count, Counter);
507          } else {
508            ComplexEdgePreds.insert(BB);
509            for (int i = 0; i != Successors; ++i)
510              ComplexEdgeSuccs.insert(TI->getSuccessor(i));
511          }
512          Edge += Successors;
513        }
514      }
515
516      if (!ComplexEdgePreds.empty()) {
517        GlobalVariable *EdgeTable =
518          buildEdgeLookupTable(F, Counters,
519                               ComplexEdgePreds, ComplexEdgeSuccs);
520        GlobalVariable *EdgeState = getEdgeStateValue();
521
522        for (int i = 0, e = ComplexEdgePreds.size(); i != e; ++i) {
523          IRBuilder<> Builder(ComplexEdgePreds[i+1]->getTerminator());
524          Builder.CreateStore(Builder.getInt32(i), EdgeState);
525        }
526        for (int i = 0, e = ComplexEdgeSuccs.size(); i != e; ++i) {
527          // call runtime to perform increment
528          BasicBlock::iterator InsertPt =
529            ComplexEdgeSuccs[i+1]->getFirstInsertionPt();
530          IRBuilder<> Builder(InsertPt);
531          Value *CounterPtrArray =
532            Builder.CreateConstInBoundsGEP2_64(EdgeTable, 0,
533                                               i * ComplexEdgePreds.size());
534
535          // Build code to increment the counter.
536          InsertIndCounterIncrCode = true;
537          Builder.CreateCall2(getIncrementIndirectCounterFunc(),
538                              EdgeState, CounterPtrArray);
539        }
540      }
541    }
542
543    Function *WriteoutF = insertCounterWriteout(CountersBySP);
544    Function *FlushF = insertFlush(CountersBySP);
545
546    // Create a small bit of code that registers the "__llvm_gcov_writeout" to
547    //  be executed at exit and the "__llvm_gcov_flush" function to be executed
548    //  when "__gcov_flush" is called.
549    FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
550    Function *F = Function::Create(FTy, GlobalValue::InternalLinkage,
551                                   "__llvm_gcov_init", M);
552    F->setUnnamedAddr(true);
553    F->setLinkage(GlobalValue::InternalLinkage);
554    F->addFnAttr(Attribute::NoInline);
555    if (Options.NoRedZone)
556      F->addFnAttr(Attribute::NoRedZone);
557
558    BasicBlock *BB = BasicBlock::Create(*Ctx, "entry", F);
559    IRBuilder<> Builder(BB);
560
561    FTy = FunctionType::get(Builder.getInt32Ty(),
562                            PointerType::get(FTy, 0), false);
563    Constant *AtExitFn = M->getOrInsertFunction("atexit", FTy);
564    Builder.CreateCall(AtExitFn, WriteoutF);
565
566    // Register the local flush function.
567    FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
568    FTy = FunctionType::get(Builder.getVoidTy(),
569                            PointerType::get(FTy, 0), false);
570    Constant *RegFlush =
571      M->getOrInsertFunction("llvm_register_flush_function", FTy);
572    Builder.CreateCall(RegFlush, FlushF);
573
574    // Make sure that all the flush function list is deleted.
575    Builder.CreateCall(AtExitFn, getDeleteFlushFunctionListFunc());
576    Builder.CreateRetVoid();
577
578    appendToGlobalCtors(*M, F, 0);
579  }
580
581  if (InsertIndCounterIncrCode)
582    insertIndirectCounterIncrement();
583
584  return Result;
585}
586
587// All edges with successors that aren't branches are "complex", because it
588// requires complex logic to pick which counter to update.
589GlobalVariable *GCOVProfiler::buildEdgeLookupTable(
590    Function *F,
591    GlobalVariable *Counters,
592    const UniqueVector<BasicBlock *> &Preds,
593    const UniqueVector<BasicBlock *> &Succs) {
594  // TODO: support invoke, threads. We rely on the fact that nothing can modify
595  // the whole-Module pred edge# between the time we set it and the time we next
596  // read it. Threads and invoke make this untrue.
597
598  // emit [(succs * preds) x i64*], logically [succ x [pred x i64*]].
599  size_t TableSize = Succs.size() * Preds.size();
600  Type *Int64PtrTy = Type::getInt64PtrTy(*Ctx);
601  ArrayType *EdgeTableTy = ArrayType::get(Int64PtrTy, TableSize);
602
603  OwningArrayPtr<Constant *> EdgeTable(new Constant*[TableSize]);
604  Constant *NullValue = Constant::getNullValue(Int64PtrTy);
605  for (size_t i = 0; i != TableSize; ++i)
606    EdgeTable[i] = NullValue;
607
608  unsigned Edge = 0;
609  for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
610    TerminatorInst *TI = BB->getTerminator();
611    int Successors = isa<ReturnInst>(TI) ? 1 : TI->getNumSuccessors();
612    if (Successors > 1 && !isa<BranchInst>(TI) && !isa<ReturnInst>(TI)) {
613      for (int i = 0; i != Successors; ++i) {
614        BasicBlock *Succ = TI->getSuccessor(i);
615        IRBuilder<> Builder(Succ);
616        Value *Counter = Builder.CreateConstInBoundsGEP2_64(Counters, 0,
617                                                            Edge + i);
618        EdgeTable[((Succs.idFor(Succ)-1) * Preds.size()) +
619                  (Preds.idFor(BB)-1)] = cast<Constant>(Counter);
620      }
621    }
622    Edge += Successors;
623  }
624
625  ArrayRef<Constant*> V(&EdgeTable[0], TableSize);
626  GlobalVariable *EdgeTableGV =
627      new GlobalVariable(
628          *M, EdgeTableTy, true, GlobalValue::InternalLinkage,
629          ConstantArray::get(EdgeTableTy, V),
630          "__llvm_gcda_edge_table");
631  EdgeTableGV->setUnnamedAddr(true);
632  return EdgeTableGV;
633}
634
635Constant *GCOVProfiler::getStartFileFunc() {
636  Type *Args[] = {
637    Type::getInt8PtrTy(*Ctx),  // const char *orig_filename
638    Type::getInt8PtrTy(*Ctx),  // const char version[4]
639  };
640  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false);
641  return M->getOrInsertFunction("llvm_gcda_start_file", FTy);
642}
643
644Constant *GCOVProfiler::getIncrementIndirectCounterFunc() {
645  Type *Int32Ty = Type::getInt32Ty(*Ctx);
646  Type *Int64Ty = Type::getInt64Ty(*Ctx);
647  Type *Args[] = {
648    Int32Ty->getPointerTo(),                // uint32_t *predecessor
649    Int64Ty->getPointerTo()->getPointerTo() // uint64_t **counters
650  };
651  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false);
652  return M->getOrInsertFunction("__llvm_gcov_indirect_counter_increment", FTy);
653}
654
655Constant *GCOVProfiler::getEmitFunctionFunc() {
656  Type *Args[3] = {
657    Type::getInt32Ty(*Ctx),    // uint32_t ident
658    Type::getInt8PtrTy(*Ctx),  // const char *function_name
659    Type::getInt8Ty(*Ctx),     // uint8_t use_extra_checksum
660  };
661  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false);
662  return M->getOrInsertFunction("llvm_gcda_emit_function", FTy);
663}
664
665Constant *GCOVProfiler::getEmitArcsFunc() {
666  Type *Args[] = {
667    Type::getInt32Ty(*Ctx),     // uint32_t num_counters
668    Type::getInt64PtrTy(*Ctx),  // uint64_t *counters
669  };
670  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false);
671  return M->getOrInsertFunction("llvm_gcda_emit_arcs", FTy);
672}
673
674Constant *GCOVProfiler::getDeleteFlushFunctionListFunc() {
675  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
676  return M->getOrInsertFunction("llvm_delete_flush_function_list", FTy);
677}
678
679Constant *GCOVProfiler::getEndFileFunc() {
680  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
681  return M->getOrInsertFunction("llvm_gcda_end_file", FTy);
682}
683
684GlobalVariable *GCOVProfiler::getEdgeStateValue() {
685  GlobalVariable *GV = M->getGlobalVariable("__llvm_gcov_global_state_pred");
686  if (!GV) {
687    GV = new GlobalVariable(*M, Type::getInt32Ty(*Ctx), false,
688                            GlobalValue::InternalLinkage,
689                            ConstantInt::get(Type::getInt32Ty(*Ctx),
690                                             0xffffffff),
691                            "__llvm_gcov_global_state_pred");
692    GV->setUnnamedAddr(true);
693  }
694  return GV;
695}
696
697Function *GCOVProfiler::insertCounterWriteout(
698    ArrayRef<std::pair<GlobalVariable *, MDNode *> > CountersBySP) {
699  FunctionType *WriteoutFTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
700  Function *WriteoutF = M->getFunction("__llvm_gcov_writeout");
701  if (!WriteoutF)
702    WriteoutF = Function::Create(WriteoutFTy, GlobalValue::InternalLinkage,
703                                 "__llvm_gcov_writeout", M);
704  WriteoutF->setUnnamedAddr(true);
705  WriteoutF->addFnAttr(Attribute::NoInline);
706  if (Options.NoRedZone)
707    WriteoutF->addFnAttr(Attribute::NoRedZone);
708
709  BasicBlock *BB = BasicBlock::Create(*Ctx, "entry", WriteoutF);
710  IRBuilder<> Builder(BB);
711
712  Constant *StartFile = getStartFileFunc();
713  Constant *EmitFunction = getEmitFunctionFunc();
714  Constant *EmitArcs = getEmitArcsFunc();
715  Constant *EndFile = getEndFileFunc();
716
717  NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
718  if (CU_Nodes) {
719    for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
720      DICompileUnit CU(CU_Nodes->getOperand(i));
721      std::string FilenameGcda = mangleName(CU, "gcda");
722      Builder.CreateCall2(StartFile,
723                          Builder.CreateGlobalStringPtr(FilenameGcda),
724                          Builder.CreateGlobalStringPtr(ReversedVersion));
725      for (unsigned j = 0, e = CountersBySP.size(); j != e; ++j) {
726        DISubprogram SP(CountersBySP[j].second);
727        Builder.CreateCall3(EmitFunction,
728                            Builder.getInt32(j),
729                            Options.FunctionNamesInData ?
730                              Builder.CreateGlobalStringPtr(SP.getName()) :
731                              Constant::getNullValue(Builder.getInt8PtrTy()),
732                            Builder.getInt8(Options.UseCfgChecksum));
733
734        GlobalVariable *GV = CountersBySP[j].first;
735        unsigned Arcs =
736          cast<ArrayType>(GV->getType()->getElementType())->getNumElements();
737        Builder.CreateCall2(EmitArcs,
738                            Builder.getInt32(Arcs),
739                            Builder.CreateConstGEP2_64(GV, 0, 0));
740      }
741      Builder.CreateCall(EndFile);
742    }
743  }
744
745  Builder.CreateRetVoid();
746  return WriteoutF;
747}
748
749void GCOVProfiler::insertIndirectCounterIncrement() {
750  Function *Fn =
751    cast<Function>(GCOVProfiler::getIncrementIndirectCounterFunc());
752  Fn->setUnnamedAddr(true);
753  Fn->setLinkage(GlobalValue::InternalLinkage);
754  Fn->addFnAttr(Attribute::NoInline);
755  if (Options.NoRedZone)
756    Fn->addFnAttr(Attribute::NoRedZone);
757
758  // Create basic blocks for function.
759  BasicBlock *BB = BasicBlock::Create(*Ctx, "entry", Fn);
760  IRBuilder<> Builder(BB);
761
762  BasicBlock *PredNotNegOne = BasicBlock::Create(*Ctx, "", Fn);
763  BasicBlock *CounterEnd = BasicBlock::Create(*Ctx, "", Fn);
764  BasicBlock *Exit = BasicBlock::Create(*Ctx, "exit", Fn);
765
766  // uint32_t pred = *predecessor;
767  // if (pred == 0xffffffff) return;
768  Argument *Arg = Fn->arg_begin();
769  Arg->setName("predecessor");
770  Value *Pred = Builder.CreateLoad(Arg, "pred");
771  Value *Cond = Builder.CreateICmpEQ(Pred, Builder.getInt32(0xffffffff));
772  BranchInst::Create(Exit, PredNotNegOne, Cond, BB);
773
774  Builder.SetInsertPoint(PredNotNegOne);
775
776  // uint64_t *counter = counters[pred];
777  // if (!counter) return;
778  Value *ZExtPred = Builder.CreateZExt(Pred, Builder.getInt64Ty());
779  Arg = llvm::next(Fn->arg_begin());
780  Arg->setName("counters");
781  Value *GEP = Builder.CreateGEP(Arg, ZExtPred);
782  Value *Counter = Builder.CreateLoad(GEP, "counter");
783  Cond = Builder.CreateICmpEQ(Counter,
784                              Constant::getNullValue(
785                                  Builder.getInt64Ty()->getPointerTo()));
786  Builder.CreateCondBr(Cond, Exit, CounterEnd);
787
788  // ++*counter;
789  Builder.SetInsertPoint(CounterEnd);
790  Value *Add = Builder.CreateAdd(Builder.CreateLoad(Counter),
791                                 Builder.getInt64(1));
792  Builder.CreateStore(Add, Counter);
793  Builder.CreateBr(Exit);
794
795  // Fill in the exit block.
796  Builder.SetInsertPoint(Exit);
797  Builder.CreateRetVoid();
798}
799
800Function *GCOVProfiler::
801insertFlush(ArrayRef<std::pair<GlobalVariable*, MDNode*> > CountersBySP) {
802  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
803  Function *FlushF = M->getFunction("__llvm_gcov_flush");
804  if (!FlushF)
805    FlushF = Function::Create(FTy, GlobalValue::InternalLinkage,
806                              "__llvm_gcov_flush", M);
807  else
808    FlushF->setLinkage(GlobalValue::InternalLinkage);
809  FlushF->setUnnamedAddr(true);
810  FlushF->addFnAttr(Attribute::NoInline);
811  if (Options.NoRedZone)
812    FlushF->addFnAttr(Attribute::NoRedZone);
813
814  BasicBlock *Entry = BasicBlock::Create(*Ctx, "entry", FlushF);
815
816  // Write out the current counters.
817  Constant *WriteoutF = M->getFunction("__llvm_gcov_writeout");
818  assert(WriteoutF && "Need to create the writeout function first!");
819
820  IRBuilder<> Builder(Entry);
821  Builder.CreateCall(WriteoutF);
822
823  // Zero out the counters.
824  for (ArrayRef<std::pair<GlobalVariable *, MDNode *> >::iterator
825         I = CountersBySP.begin(), E = CountersBySP.end();
826       I != E; ++I) {
827    GlobalVariable *GV = I->first;
828    Constant *Null = Constant::getNullValue(GV->getType()->getElementType());
829    Builder.CreateStore(Null, GV);
830  }
831
832  Type *RetTy = FlushF->getReturnType();
833  if (RetTy == Type::getVoidTy(*Ctx))
834    Builder.CreateRetVoid();
835  else if (RetTy->isIntegerTy())
836    // Used if __llvm_gcov_flush was implicitly declared.
837    Builder.CreateRet(ConstantInt::get(RetTy, 0));
838  else
839    report_fatal_error("invalid return type for __llvm_gcov_flush");
840
841  return FlushF;
842}
843