GCOVProfiling.cpp revision 263508 
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 "llvm/ADT/DenseMap.h"
21#include "llvm/ADT/STLExtras.h"
22#include "llvm/ADT/Statistic.h"
23#include "llvm/ADT/StringExtras.h"
24#include "llvm/ADT/StringMap.h"
25#include "llvm/ADT/UniqueVector.h"
26#include "llvm/DebugInfo.h"
27#include "llvm/IR/IRBuilder.h"
28#include "llvm/IR/Instructions.h"
29#include "llvm/IR/Module.h"
30#include "llvm/Pass.h"
31#include "llvm/Support/CommandLine.h"
32#include "llvm/Support/Debug.h"
33#include "llvm/Support/DebugLoc.h"
34#include "llvm/Support/FileSystem.h"
35#include "llvm/Support/InstIterator.h"
36#include "llvm/Support/Path.h"
37#include "llvm/Support/raw_ostream.h"
38#include "llvm/Transforms/Utils/ModuleUtils.h"
39#include <algorithm>
40#include <string>
41#include <utility>
42using namespace llvm;
43
44static cl::opt<std::string>
45DefaultGCOVVersion("default-gcov-version", cl::init("402*"), cl::Hidden,
46                   cl::ValueRequired);
47
48GCOVOptions GCOVOptions::getDefault() {
49  GCOVOptions Options;
50  Options.EmitNotes = true;
51  Options.EmitData = true;
52  Options.UseCfgChecksum = false;
53  Options.NoRedZone = false;
54  Options.FunctionNamesInData = true;
55
56  if (DefaultGCOVVersion.size() != 4) {
57    llvm::report_fatal_error(std::string("Invalid -default-gcov-version: ") +
58                             DefaultGCOVVersion);
59  }
60  memcpy(Options.Version, DefaultGCOVVersion.c_str(), 4);
61  return Options;
62}
63
64namespace {
65  class GCOVProfiler : public ModulePass {
66  public:
67    static char ID;
68    GCOVProfiler() : ModulePass(ID), Options(GCOVOptions::getDefault()) {
69      ReversedVersion[0] = Options.Version[3];
70      ReversedVersion[1] = Options.Version[2];
71      ReversedVersion[2] = Options.Version[1];
72      ReversedVersion[3] = Options.Version[0];
73      ReversedVersion[4] = '\0';
74      initializeGCOVProfilerPass(*PassRegistry::getPassRegistry());
75    }
76    GCOVProfiler(const GCOVOptions &Options) : ModulePass(ID), Options(Options){
77      assert((Options.EmitNotes || Options.EmitData) &&
78             "GCOVProfiler asked to do nothing?");
79      ReversedVersion[0] = Options.Version[3];
80      ReversedVersion[1] = Options.Version[2];
81      ReversedVersion[2] = Options.Version[1];
82      ReversedVersion[3] = Options.Version[0];
83      ReversedVersion[4] = '\0';
84      initializeGCOVProfilerPass(*PassRegistry::getPassRegistry());
85    }
86    virtual const char *getPassName() const {
87      return "GCOV Profiler";
88    }
89
90  private:
91    bool runOnModule(Module &M);
92
93    // Create the .gcno files for the Module based on DebugInfo.
94    void emitProfileNotes();
95
96    // Modify the program to track transitions along edges and call into the
97    // profiling runtime to emit .gcda files when run.
98    bool emitProfileArcs();
99
100    // Get pointers to the functions in the runtime library.
101    Constant *getStartFileFunc();
102    Constant *getIncrementIndirectCounterFunc();
103    Constant *getEmitFunctionFunc();
104    Constant *getEmitArcsFunc();
105    Constant *getSummaryInfoFunc();
106    Constant *getDeleteWriteoutFunctionListFunc();
107    Constant *getDeleteFlushFunctionListFunc();
108    Constant *getEndFileFunc();
109
110    // Create or retrieve an i32 state value that is used to represent the
111    // pred block number for certain non-trivial edges.
112    GlobalVariable *getEdgeStateValue();
113
114    // Produce a table of pointers to counters, by predecessor and successor
115    // block number.
116    GlobalVariable *buildEdgeLookupTable(Function *F,
117                                         GlobalVariable *Counter,
118                                         const UniqueVector<BasicBlock *>&Preds,
119                                         const UniqueVector<BasicBlock*>&Succs);
120
121    // Add the function to write out all our counters to the global destructor
122    // list.
123    Function *insertCounterWriteout(ArrayRef<std::pair<GlobalVariable*,
124                                                       MDNode*> >);
125    Function *insertFlush(ArrayRef<std::pair<GlobalVariable*, MDNode*> >);
126    void insertIndirectCounterIncrement();
127
128    std::string mangleName(DICompileUnit CU, const char *NewStem);
129
130    GCOVOptions Options;
131
132    // Reversed, NUL-terminated copy of Options.Version.
133    char ReversedVersion[5];
134
135    Module *M;
136    LLVMContext *Ctx;
137  };
138}
139
140char GCOVProfiler::ID = 0;
141INITIALIZE_PASS(GCOVProfiler, "insert-gcov-profiling",
142                "Insert instrumentation for GCOV profiling", false, false)
143
144ModulePass *llvm::createGCOVProfilerPass(const GCOVOptions &Options) {
145  return new GCOVProfiler(Options);
146}
147
148static std::string getFunctionName(DISubprogram SP) {
149  if (!SP.getLinkageName().empty())
150    return SP.getLinkageName();
151  return SP.getName();
152}
153
154namespace {
155  class GCOVRecord {
156   protected:
157    static const char *const LinesTag;
158    static const char *const FunctionTag;
159    static const char *const BlockTag;
160    static const char *const EdgeTag;
161
162    GCOVRecord() {}
163
164    void writeBytes(const char *Bytes, int Size) {
165      os->write(Bytes, Size);
166    }
167
168    void write(uint32_t i) {
169      writeBytes(reinterpret_cast<char*>(&i), 4);
170    }
171
172    // Returns the length measured in 4-byte blocks that will be used to
173    // represent this string in a GCOV file
174    static unsigned lengthOfGCOVString(StringRef s) {
175      // A GCOV string is a length, followed by a NUL, then between 0 and 3 NULs
176      // padding out to the next 4-byte word. The length is measured in 4-byte
177      // words including padding, not bytes of actual string.
178      return (s.size() / 4) + 1;
179    }
180
181    void writeGCOVString(StringRef s) {
182      uint32_t Len = lengthOfGCOVString(s);
183      write(Len);
184      writeBytes(s.data(), s.size());
185
186      // Write 1 to 4 bytes of NUL padding.
187      assert((unsigned)(4 - (s.size() % 4)) > 0);
188      assert((unsigned)(4 - (s.size() % 4)) <= 4);
189      writeBytes("\0\0\0\0", 4 - (s.size() % 4));
190    }
191
192    raw_ostream *os;
193  };
194  const char *const GCOVRecord::LinesTag = "\0\0\x45\x01";
195  const char *const GCOVRecord::FunctionTag = "\0\0\0\1";
196  const char *const GCOVRecord::BlockTag = "\0\0\x41\x01";
197  const char *const GCOVRecord::EdgeTag = "\0\0\x43\x01";
198
199  class GCOVFunction;
200  class GCOVBlock;
201
202  // Constructed only by requesting it from a GCOVBlock, this object stores a
203  // list of line numbers and a single filename, representing lines that belong
204  // to the block.
205  class GCOVLines : public GCOVRecord {
206   public:
207    void addLine(uint32_t Line) {
208      Lines.push_back(Line);
209    }
210
211    uint32_t length() const {
212      // Here 2 = 1 for string length + 1 for '0' id#.
213      return lengthOfGCOVString(Filename) + 2 + Lines.size();
214    }
215
216    void writeOut() {
217      write(0);
218      writeGCOVString(Filename);
219      for (int i = 0, e = Lines.size(); i != e; ++i)
220        write(Lines[i]);
221    }
222
223    GCOVLines(StringRef F, raw_ostream *os)
224      : Filename(F) {
225      this->os = os;
226    }
227
228   private:
229    StringRef Filename;
230    SmallVector<uint32_t, 32> Lines;
231  };
232
233
234  // Sorting function for deterministic behaviour in GCOVBlock::writeOut.
235  struct StringKeySort {
236    bool operator()(StringMapEntry<GCOVLines *> *LHS,
237                    StringMapEntry<GCOVLines *> *RHS) const {
238      return LHS->getKey() < RHS->getKey();
239    }
240  };
241
242  // Represent a basic block in GCOV. Each block has a unique number in the
243  // function, number of lines belonging to each block, and a set of edges to
244  // other blocks.
245  class GCOVBlock : public GCOVRecord {
246   public:
247    GCOVLines &getFile(StringRef Filename) {
248      GCOVLines *&Lines = LinesByFile[Filename];
249      if (!Lines) {
250        Lines = new GCOVLines(Filename, os);
251      }
252      return *Lines;
253    }
254
255    void addEdge(GCOVBlock &Successor) {
256      OutEdges.push_back(&Successor);
257    }
258
259    void writeOut() {
260      uint32_t Len = 3;
261      SmallVector<StringMapEntry<GCOVLines *> *, 32> SortedLinesByFile;
262      for (StringMap<GCOVLines *>::iterator I = LinesByFile.begin(),
263               E = LinesByFile.end(); I != E; ++I) {
264        Len += I->second->length();
265        SortedLinesByFile.push_back(&*I);
266      }
267
268      writeBytes(LinesTag, 4);
269      write(Len);
270      write(Number);
271
272      StringKeySort Sorter;
273      std::sort(SortedLinesByFile.begin(), SortedLinesByFile.end(), Sorter);
274      for (SmallVectorImpl<StringMapEntry<GCOVLines *> *>::iterator
275               I = SortedLinesByFile.begin(), E = SortedLinesByFile.end();
276           I != E; ++I)
277        (*I)->getValue()->writeOut();
278      write(0);
279      write(0);
280    }
281
282    ~GCOVBlock() {
283      DeleteContainerSeconds(LinesByFile);
284    }
285
286   private:
287    friend class GCOVFunction;
288
289    GCOVBlock(uint32_t Number, raw_ostream *os)
290        : Number(Number) {
291      this->os = os;
292    }
293
294    uint32_t Number;
295    StringMap<GCOVLines *> LinesByFile;
296    SmallVector<GCOVBlock *, 4> OutEdges;
297  };
298
299  // A function has a unique identifier, a checksum (we leave as zero) and a
300  // set of blocks and a map of edges between blocks. This is the only GCOV
301  // object users can construct, the blocks and lines will be rooted here.
302  class GCOVFunction : public GCOVRecord {
303   public:
304    GCOVFunction(DISubprogram SP, raw_ostream *os, uint32_t Ident,
305                 bool UseCfgChecksum) {
306      this->os = os;
307
308      Function *F = SP.getFunction();
309      DEBUG(dbgs() << "Function: " << F->getName() << "\n");
310      uint32_t i = 0;
311      for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
312        Blocks[BB] = new GCOVBlock(i++, os);
313      }
314      ReturnBlock = new GCOVBlock(i++, os);
315
316      writeBytes(FunctionTag, 4);
317      uint32_t BlockLen = 1 + 1 + 1 + lengthOfGCOVString(getFunctionName(SP)) +
318          1 + lengthOfGCOVString(SP.getFilename()) + 1;
319      if (UseCfgChecksum)
320        ++BlockLen;
321      write(BlockLen);
322      write(Ident);
323      write(0);  // lineno checksum
324      if (UseCfgChecksum)
325        write(0);  // cfg checksum
326      writeGCOVString(getFunctionName(SP));
327      writeGCOVString(SP.getFilename());
328      write(SP.getLineNumber());
329    }
330
331    ~GCOVFunction() {
332      DeleteContainerSeconds(Blocks);
333      delete ReturnBlock;
334    }
335
336    GCOVBlock &getBlock(BasicBlock *BB) {
337      return *Blocks[BB];
338    }
339
340    GCOVBlock &getReturnBlock() {
341      return *ReturnBlock;
342    }
343
344    void writeOut() {
345      // Emit count of blocks.
346      writeBytes(BlockTag, 4);
347      write(Blocks.size() + 1);
348      for (int i = 0, e = Blocks.size() + 1; i != e; ++i) {
349        write(0);  // No flags on our blocks.
350      }
351      DEBUG(dbgs() << Blocks.size() << " blocks.\n");
352
353      // Emit edges between blocks.
354      if (Blocks.empty()) return;
355      Function *F = Blocks.begin()->first->getParent();
356      for (Function::iterator I = F->begin(), E = F->end(); I != E; ++I) {
357        GCOVBlock &Block = *Blocks[I];
358        if (Block.OutEdges.empty()) continue;
359
360        writeBytes(EdgeTag, 4);
361        write(Block.OutEdges.size() * 2 + 1);
362        write(Block.Number);
363        for (int i = 0, e = Block.OutEdges.size(); i != e; ++i) {
364          DEBUG(dbgs() << Block.Number << " -> " << Block.OutEdges[i]->Number
365                       << "\n");
366          write(Block.OutEdges[i]->Number);
367          write(0);  // no flags
368        }
369      }
370
371      // Emit lines for each block.
372      for (Function::iterator I = F->begin(), E = F->end(); I != E; ++I) {
373        Blocks[I]->writeOut();
374      }
375    }
376
377   private:
378    DenseMap<BasicBlock *, GCOVBlock *> Blocks;
379    GCOVBlock *ReturnBlock;
380  };
381}
382
383std::string GCOVProfiler::mangleName(DICompileUnit CU, const char *NewStem) {
384  if (NamedMDNode *GCov = M->getNamedMetadata("llvm.gcov")) {
385    for (int i = 0, e = GCov->getNumOperands(); i != e; ++i) {
386      MDNode *N = GCov->getOperand(i);
387      if (N->getNumOperands() != 2) continue;
388      MDString *GCovFile = dyn_cast<MDString>(N->getOperand(0));
389      MDNode *CompileUnit = dyn_cast<MDNode>(N->getOperand(1));
390      if (!GCovFile || !CompileUnit) continue;
391      if (CompileUnit == CU) {
392        SmallString<128> Filename = GCovFile->getString();
393        sys::path::replace_extension(Filename, NewStem);
394        return Filename.str();
395      }
396    }
397  }
398
399  SmallString<128> Filename = CU.getFilename();
400  sys::path::replace_extension(Filename, NewStem);
401  StringRef FName = sys::path::filename(Filename);
402  SmallString<128> CurPath;
403  if (sys::fs::current_path(CurPath)) return FName;
404  sys::path::append(CurPath, FName.str());
405  return CurPath.str();
406}
407
408bool GCOVProfiler::runOnModule(Module &M) {
409  this->M = &M;
410  Ctx = &M.getContext();
411
412  if (Options.EmitNotes) emitProfileNotes();
413  if (Options.EmitData) return emitProfileArcs();
414  return false;
415}
416
417void GCOVProfiler::emitProfileNotes() {
418  NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
419  if (!CU_Nodes) return;
420
421  for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
422    // Each compile unit gets its own .gcno file. This means that whether we run
423    // this pass over the original .o's as they're produced, or run it after
424    // LTO, we'll generate the same .gcno files.
425
426    DICompileUnit CU(CU_Nodes->getOperand(i));
427    std::string ErrorInfo;
428    raw_fd_ostream out(mangleName(CU, "gcno").c_str(), ErrorInfo,
429                       sys::fs::F_Binary);
430    out.write("oncg", 4);
431    out.write(ReversedVersion, 4);
432    out.write("MVLL", 4);
433
434    DIArray SPs = CU.getSubprograms();
435    for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i) {
436      DISubprogram SP(SPs.getElement(i));
437      assert((!SP || SP.isSubprogram()) &&
438        "A MDNode in subprograms of a CU should be null or a DISubprogram.");
439      if (!SP)
440        continue;
441
442      Function *F = SP.getFunction();
443      if (!F) continue;
444      GCOVFunction Func(SP, &out, i, Options.UseCfgChecksum);
445
446      for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
447        GCOVBlock &Block = Func.getBlock(BB);
448        TerminatorInst *TI = BB->getTerminator();
449        if (int successors = TI->getNumSuccessors()) {
450          for (int i = 0; i != successors; ++i) {
451            Block.addEdge(Func.getBlock(TI->getSuccessor(i)));
452          }
453        } else if (isa<ReturnInst>(TI)) {
454          Block.addEdge(Func.getReturnBlock());
455        }
456
457        uint32_t Line = 0;
458        for (BasicBlock::iterator I = BB->begin(), IE = BB->end();
459             I != IE; ++I) {
460          const DebugLoc &Loc = I->getDebugLoc();
461          if (Loc.isUnknown()) continue;
462          if (Line == Loc.getLine()) continue;
463          Line = Loc.getLine();
464          if (SP != getDISubprogram(Loc.getScope(*Ctx))) continue;
465
466          GCOVLines &Lines = Block.getFile(SP.getFilename());
467          Lines.addLine(Loc.getLine());
468        }
469      }
470      Func.writeOut();
471    }
472    out.write("\0\0\0\0\0\0\0\0", 8);  // EOF
473    out.close();
474  }
475}
476
477bool GCOVProfiler::emitProfileArcs() {
478  NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
479  if (!CU_Nodes) return false;
480
481  bool Result = false;
482  bool InsertIndCounterIncrCode = false;
483  for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
484    DICompileUnit CU(CU_Nodes->getOperand(i));
485    DIArray SPs = CU.getSubprograms();
486    SmallVector<std::pair<GlobalVariable *, MDNode *>, 8> CountersBySP;
487    for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i) {
488      DISubprogram SP(SPs.getElement(i));
489      assert((!SP || SP.isSubprogram()) &&
490        "A MDNode in subprograms of a CU should be null or a DISubprogram.");
491      if (!SP)
492        continue;
493      Function *F = SP.getFunction();
494      if (!F) continue;
495      if (!Result) Result = true;
496      unsigned Edges = 0;
497      for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
498        TerminatorInst *TI = BB->getTerminator();
499        if (isa<ReturnInst>(TI))
500          ++Edges;
501        else
502          Edges += TI->getNumSuccessors();
503      }
504
505      ArrayType *CounterTy =
506        ArrayType::get(Type::getInt64Ty(*Ctx), Edges);
507      GlobalVariable *Counters =
508        new GlobalVariable(*M, CounterTy, false,
509                           GlobalValue::InternalLinkage,
510                           Constant::getNullValue(CounterTy),
511                           "__llvm_gcov_ctr");
512      CountersBySP.push_back(std::make_pair(Counters, (MDNode*)SP));
513
514      UniqueVector<BasicBlock *> ComplexEdgePreds;
515      UniqueVector<BasicBlock *> ComplexEdgeSuccs;
516
517      unsigned Edge = 0;
518      for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
519        TerminatorInst *TI = BB->getTerminator();
520        int Successors = isa<ReturnInst>(TI) ? 1 : TI->getNumSuccessors();
521        if (Successors) {
522          if (Successors == 1) {
523            IRBuilder<> Builder(BB->getFirstInsertionPt());
524            Value *Counter = Builder.CreateConstInBoundsGEP2_64(Counters, 0,
525                                                                Edge);
526            Value *Count = Builder.CreateLoad(Counter);
527            Count = Builder.CreateAdd(Count, Builder.getInt64(1));
528            Builder.CreateStore(Count, Counter);
529          } else if (BranchInst *BI = dyn_cast<BranchInst>(TI)) {
530            IRBuilder<> Builder(BI);
531            Value *Sel = Builder.CreateSelect(BI->getCondition(),
532                                              Builder.getInt64(Edge),
533                                              Builder.getInt64(Edge + 1));
534            SmallVector<Value *, 2> Idx;
535            Idx.push_back(Builder.getInt64(0));
536            Idx.push_back(Sel);
537            Value *Counter = Builder.CreateInBoundsGEP(Counters, Idx);
538            Value *Count = Builder.CreateLoad(Counter);
539            Count = Builder.CreateAdd(Count, Builder.getInt64(1));
540            Builder.CreateStore(Count, Counter);
541          } else {
542            ComplexEdgePreds.insert(BB);
543            for (int i = 0; i != Successors; ++i)
544              ComplexEdgeSuccs.insert(TI->getSuccessor(i));
545          }
546
547          Edge += Successors;
548        }
549      }
550
551      if (!ComplexEdgePreds.empty()) {
552        GlobalVariable *EdgeTable =
553          buildEdgeLookupTable(F, Counters,
554                               ComplexEdgePreds, ComplexEdgeSuccs);
555        GlobalVariable *EdgeState = getEdgeStateValue();
556
557        for (int i = 0, e = ComplexEdgePreds.size(); i != e; ++i) {
558          IRBuilder<> Builder(ComplexEdgePreds[i + 1]->getFirstInsertionPt());
559          Builder.CreateStore(Builder.getInt32(i), EdgeState);
560        }
561
562        for (int i = 0, e = ComplexEdgeSuccs.size(); i != e; ++i) {
563          // Call runtime to perform increment.
564          IRBuilder<> Builder(ComplexEdgeSuccs[i+1]->getFirstInsertionPt());
565          Value *CounterPtrArray =
566            Builder.CreateConstInBoundsGEP2_64(EdgeTable, 0,
567                                               i * ComplexEdgePreds.size());
568
569          // Build code to increment the counter.
570          InsertIndCounterIncrCode = true;
571          Builder.CreateCall2(getIncrementIndirectCounterFunc(),
572                              EdgeState, CounterPtrArray);
573        }
574      }
575    }
576
577    Function *WriteoutF = insertCounterWriteout(CountersBySP);
578    Function *FlushF = insertFlush(CountersBySP);
579
580    // Create a small bit of code that registers the "__llvm_gcov_writeout" to
581    // be executed at exit and the "__llvm_gcov_flush" function to be executed
582    // when "__gcov_flush" is called.
583    FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
584    Function *F = Function::Create(FTy, GlobalValue::InternalLinkage,
585                                   "__llvm_gcov_init", M);
586    F->setUnnamedAddr(true);
587    F->setLinkage(GlobalValue::InternalLinkage);
588    F->addFnAttr(Attribute::NoInline);
589    if (Options.NoRedZone)
590      F->addFnAttr(Attribute::NoRedZone);
591
592    BasicBlock *BB = BasicBlock::Create(*Ctx, "entry", F);
593    IRBuilder<> Builder(BB);
594
595    FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
596    Type *Params[] = {
597      PointerType::get(FTy, 0),
598      PointerType::get(FTy, 0)
599    };
600    FTy = FunctionType::get(Builder.getVoidTy(), Params, false);
601
602    // Initialize the environment and register the local writeout and flush
603    // functions.
604    Constant *GCOVInit = M->getOrInsertFunction("llvm_gcov_init", FTy);
605    Builder.CreateCall2(GCOVInit, WriteoutF, FlushF);
606    Builder.CreateRetVoid();
607
608    appendToGlobalCtors(*M, F, 0);
609  }
610
611  if (InsertIndCounterIncrCode)
612    insertIndirectCounterIncrement();
613
614  return Result;
615}
616
617// All edges with successors that aren't branches are "complex", because it
618// requires complex logic to pick which counter to update.
619GlobalVariable *GCOVProfiler::buildEdgeLookupTable(
620    Function *F,
621    GlobalVariable *Counters,
622    const UniqueVector<BasicBlock *> &Preds,
623    const UniqueVector<BasicBlock *> &Succs) {
624  // TODO: support invoke, threads. We rely on the fact that nothing can modify
625  // the whole-Module pred edge# between the time we set it and the time we next
626  // read it. Threads and invoke make this untrue.
627
628  // emit [(succs * preds) x i64*], logically [succ x [pred x i64*]].
629  size_t TableSize = Succs.size() * Preds.size();
630  Type *Int64PtrTy = Type::getInt64PtrTy(*Ctx);
631  ArrayType *EdgeTableTy = ArrayType::get(Int64PtrTy, TableSize);
632
633  OwningArrayPtr<Constant *> EdgeTable(new Constant*[TableSize]);
634  Constant *NullValue = Constant::getNullValue(Int64PtrTy);
635  for (size_t i = 0; i != TableSize; ++i)
636    EdgeTable[i] = NullValue;
637
638  unsigned Edge = 0;
639  for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
640    TerminatorInst *TI = BB->getTerminator();
641    int Successors = isa<ReturnInst>(TI) ? 1 : TI->getNumSuccessors();
642    if (Successors > 1 && !isa<BranchInst>(TI) && !isa<ReturnInst>(TI)) {
643      for (int i = 0; i != Successors; ++i) {
644        BasicBlock *Succ = TI->getSuccessor(i);
645        IRBuilder<> Builder(Succ);
646        Value *Counter = Builder.CreateConstInBoundsGEP2_64(Counters, 0,
647                                                            Edge + i);
648        EdgeTable[((Succs.idFor(Succ)-1) * Preds.size()) +
649                  (Preds.idFor(BB)-1)] = cast<Constant>(Counter);
650      }
651    }
652    Edge += Successors;
653  }
654
655  ArrayRef<Constant*> V(&EdgeTable[0], TableSize);
656  GlobalVariable *EdgeTableGV =
657      new GlobalVariable(
658          *M, EdgeTableTy, true, GlobalValue::InternalLinkage,
659          ConstantArray::get(EdgeTableTy, V),
660          "__llvm_gcda_edge_table");
661  EdgeTableGV->setUnnamedAddr(true);
662  return EdgeTableGV;
663}
664
665Constant *GCOVProfiler::getStartFileFunc() {
666  Type *Args[] = {
667    Type::getInt8PtrTy(*Ctx),  // const char *orig_filename
668    Type::getInt8PtrTy(*Ctx),  // const char version[4]
669  };
670  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false);
671  return M->getOrInsertFunction("llvm_gcda_start_file", FTy);
672}
673
674Constant *GCOVProfiler::getIncrementIndirectCounterFunc() {
675  Type *Int32Ty = Type::getInt32Ty(*Ctx);
676  Type *Int64Ty = Type::getInt64Ty(*Ctx);
677  Type *Args[] = {
678    Int32Ty->getPointerTo(),                // uint32_t *predecessor
679    Int64Ty->getPointerTo()->getPointerTo() // uint64_t **counters
680  };
681  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false);
682  return M->getOrInsertFunction("__llvm_gcov_indirect_counter_increment", FTy);
683}
684
685Constant *GCOVProfiler::getEmitFunctionFunc() {
686  Type *Args[3] = {
687    Type::getInt32Ty(*Ctx),    // uint32_t ident
688    Type::getInt8PtrTy(*Ctx),  // const char *function_name
689    Type::getInt8Ty(*Ctx),     // uint8_t use_extra_checksum
690  };
691  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false);
692  return M->getOrInsertFunction("llvm_gcda_emit_function", FTy);
693}
694
695Constant *GCOVProfiler::getEmitArcsFunc() {
696  Type *Args[] = {
697    Type::getInt32Ty(*Ctx),     // uint32_t num_counters
698    Type::getInt64PtrTy(*Ctx),  // uint64_t *counters
699  };
700  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false);
701  return M->getOrInsertFunction("llvm_gcda_emit_arcs", FTy);
702}
703
704Constant *GCOVProfiler::getSummaryInfoFunc() {
705  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
706  return M->getOrInsertFunction("llvm_gcda_summary_info", FTy);
707}
708
709Constant *GCOVProfiler::getDeleteWriteoutFunctionListFunc() {
710  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
711  return M->getOrInsertFunction("llvm_delete_writeout_function_list", FTy);
712}
713
714Constant *GCOVProfiler::getDeleteFlushFunctionListFunc() {
715  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
716  return M->getOrInsertFunction("llvm_delete_flush_function_list", FTy);
717}
718
719Constant *GCOVProfiler::getEndFileFunc() {
720  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
721  return M->getOrInsertFunction("llvm_gcda_end_file", FTy);
722}
723
724GlobalVariable *GCOVProfiler::getEdgeStateValue() {
725  GlobalVariable *GV = M->getGlobalVariable("__llvm_gcov_global_state_pred");
726  if (!GV) {
727    GV = new GlobalVariable(*M, Type::getInt32Ty(*Ctx), false,
728                            GlobalValue::InternalLinkage,
729                            ConstantInt::get(Type::getInt32Ty(*Ctx),
730                                             0xffffffff),
731                            "__llvm_gcov_global_state_pred");
732    GV->setUnnamedAddr(true);
733  }
734  return GV;
735}
736
737Function *GCOVProfiler::insertCounterWriteout(
738    ArrayRef<std::pair<GlobalVariable *, MDNode *> > CountersBySP) {
739  FunctionType *WriteoutFTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
740  Function *WriteoutF = M->getFunction("__llvm_gcov_writeout");
741  if (!WriteoutF)
742    WriteoutF = Function::Create(WriteoutFTy, GlobalValue::InternalLinkage,
743                                 "__llvm_gcov_writeout", M);
744  WriteoutF->setUnnamedAddr(true);
745  WriteoutF->addFnAttr(Attribute::NoInline);
746  if (Options.NoRedZone)
747    WriteoutF->addFnAttr(Attribute::NoRedZone);
748
749  BasicBlock *BB = BasicBlock::Create(*Ctx, "entry", WriteoutF);
750  IRBuilder<> Builder(BB);
751
752  Constant *StartFile = getStartFileFunc();
753  Constant *EmitFunction = getEmitFunctionFunc();
754  Constant *EmitArcs = getEmitArcsFunc();
755  Constant *SummaryInfo = getSummaryInfoFunc();
756  Constant *EndFile = getEndFileFunc();
757
758  NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
759  if (CU_Nodes) {
760    for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
761      DICompileUnit CU(CU_Nodes->getOperand(i));
762      std::string FilenameGcda = mangleName(CU, "gcda");
763      Builder.CreateCall2(StartFile,
764                          Builder.CreateGlobalStringPtr(FilenameGcda),
765                          Builder.CreateGlobalStringPtr(ReversedVersion));
766      for (unsigned j = 0, e = CountersBySP.size(); j != e; ++j) {
767        DISubprogram SP(CountersBySP[j].second);
768        Builder.CreateCall3(
769            EmitFunction, Builder.getInt32(j),
770            Options.FunctionNamesInData ?
771              Builder.CreateGlobalStringPtr(getFunctionName(SP)) :
772              Constant::getNullValue(Builder.getInt8PtrTy()),
773            Builder.getInt8(Options.UseCfgChecksum));
774
775        GlobalVariable *GV = CountersBySP[j].first;
776        unsigned Arcs =
777          cast<ArrayType>(GV->getType()->getElementType())->getNumElements();
778        Builder.CreateCall2(EmitArcs,
779                            Builder.getInt32(Arcs),
780                            Builder.CreateConstGEP2_64(GV, 0, 0));
781      }
782      Builder.CreateCall(SummaryInfo);
783      Builder.CreateCall(EndFile);
784    }
785  }
786
787  Builder.CreateRetVoid();
788  return WriteoutF;
789}
790
791void GCOVProfiler::insertIndirectCounterIncrement() {
792  Function *Fn =
793    cast<Function>(GCOVProfiler::getIncrementIndirectCounterFunc());
794  Fn->setUnnamedAddr(true);
795  Fn->setLinkage(GlobalValue::InternalLinkage);
796  Fn->addFnAttr(Attribute::NoInline);
797  if (Options.NoRedZone)
798    Fn->addFnAttr(Attribute::NoRedZone);
799
800  // Create basic blocks for function.
801  BasicBlock *BB = BasicBlock::Create(*Ctx, "entry", Fn);
802  IRBuilder<> Builder(BB);
803
804  BasicBlock *PredNotNegOne = BasicBlock::Create(*Ctx, "", Fn);
805  BasicBlock *CounterEnd = BasicBlock::Create(*Ctx, "", Fn);
806  BasicBlock *Exit = BasicBlock::Create(*Ctx, "exit", Fn);
807
808  // uint32_t pred = *predecessor;
809  // if (pred == 0xffffffff) return;
810  Argument *Arg = Fn->arg_begin();
811  Arg->setName("predecessor");
812  Value *Pred = Builder.CreateLoad(Arg, "pred");
813  Value *Cond = Builder.CreateICmpEQ(Pred, Builder.getInt32(0xffffffff));
814  BranchInst::Create(Exit, PredNotNegOne, Cond, BB);
815
816  Builder.SetInsertPoint(PredNotNegOne);
817
818  // uint64_t *counter = counters[pred];
819  // if (!counter) return;
820  Value *ZExtPred = Builder.CreateZExt(Pred, Builder.getInt64Ty());
821  Arg = llvm::next(Fn->arg_begin());
822  Arg->setName("counters");
823  Value *GEP = Builder.CreateGEP(Arg, ZExtPred);
824  Value *Counter = Builder.CreateLoad(GEP, "counter");
825  Cond = Builder.CreateICmpEQ(Counter,
826                              Constant::getNullValue(
827                                  Builder.getInt64Ty()->getPointerTo()));
828  Builder.CreateCondBr(Cond, Exit, CounterEnd);
829
830  // ++*counter;
831  Builder.SetInsertPoint(CounterEnd);
832  Value *Add = Builder.CreateAdd(Builder.CreateLoad(Counter),
833                                 Builder.getInt64(1));
834  Builder.CreateStore(Add, Counter);
835  Builder.CreateBr(Exit);
836
837  // Fill in the exit block.
838  Builder.SetInsertPoint(Exit);
839  Builder.CreateRetVoid();
840}
841
842Function *GCOVProfiler::
843insertFlush(ArrayRef<std::pair<GlobalVariable*, MDNode*> > CountersBySP) {
844  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
845  Function *FlushF = M->getFunction("__llvm_gcov_flush");
846  if (!FlushF)
847    FlushF = Function::Create(FTy, GlobalValue::InternalLinkage,
848                              "__llvm_gcov_flush", M);
849  else
850    FlushF->setLinkage(GlobalValue::InternalLinkage);
851  FlushF->setUnnamedAddr(true);
852  FlushF->addFnAttr(Attribute::NoInline);
853  if (Options.NoRedZone)
854    FlushF->addFnAttr(Attribute::NoRedZone);
855
856  BasicBlock *Entry = BasicBlock::Create(*Ctx, "entry", FlushF);
857
858  // Write out the current counters.
859  Constant *WriteoutF = M->getFunction("__llvm_gcov_writeout");
860  assert(WriteoutF && "Need to create the writeout function first!");
861
862  IRBuilder<> Builder(Entry);
863  Builder.CreateCall(WriteoutF);
864
865  // Zero out the counters.
866  for (ArrayRef<std::pair<GlobalVariable *, MDNode *> >::iterator
867         I = CountersBySP.begin(), E = CountersBySP.end();
868       I != E; ++I) {
869    GlobalVariable *GV = I->first;
870    Constant *Null = Constant::getNullValue(GV->getType()->getElementType());
871    Builder.CreateStore(Null, GV);
872  }
873
874  Type *RetTy = FlushF->getReturnType();
875  if (RetTy == Type::getVoidTy(*Ctx))
876    Builder.CreateRetVoid();
877  else if (RetTy->isIntegerTy())
878    // Used if __llvm_gcov_flush was implicitly declared.
879    Builder.CreateRet(ConstantInt::get(RetTy, 0));
880  else
881    report_fatal_error("invalid return type for __llvm_gcov_flush");
882
883  return FlushF;
884}
885