lib/Transforms/Instrumentation/GCOVProfiling.cpp

   1 //===- GCOVProfiling.cpp - Insert edge counters for gcov profiling --------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This pass implements GCOV-style profiling. When this pass is run it emits
  10 // "gcno" files next to the existing source, and instruments the code that runs
  11 // to records the edges between blocks that run and emit a complementary "gcda"
  12 // file on exit.
  13 //
  14 //===----------------------------------------------------------------------===//
  15
  16 #include "llvm/ADT/DenseMap.h"
  17 #include "llvm/ADT/Hashing.h"
  18 #include "llvm/ADT/STLExtras.h"
  19 #include "llvm/ADT/Sequence.h"
  20 #include "llvm/ADT/Statistic.h"
  21 #include "llvm/ADT/StringExtras.h"
  22 #include "llvm/ADT/StringMap.h"
  23 #include "llvm/Analysis/EHPersonalities.h"
  24 #include "llvm/Analysis/TargetLibraryInfo.h"
  25 #include "llvm/IR/CFG.h"
  26 #include "llvm/IR/DebugInfo.h"
  27 #include "llvm/IR/DebugLoc.h"
  28 #include "llvm/IR/IRBuilder.h"
  29 #include "llvm/IR/InstIterator.h"
  30 #include "llvm/IR/Instructions.h"
  31 #include "llvm/IR/IntrinsicInst.h"
  32 #include "llvm/IR/Module.h"
  33 #include "llvm/Pass.h"
  34 #include "llvm/Support/CommandLine.h"
  35 #include "llvm/Support/Debug.h"
  36 #include "llvm/Support/FileSystem.h"
  37 #include "llvm/Support/Path.h"
  38 #include "llvm/Support/Regex.h"
  39 #include "llvm/Support/raw_ostream.h"
  40 #include "llvm/Transforms/Instrumentation.h"
  41 #include "llvm/Transforms/Instrumentation/GCOVProfiler.h"
  42 #include "llvm/Transforms/Utils/ModuleUtils.h"
  43 #include <algorithm>
  44 #include <memory>
  45 #include <string>
  46 #include <utility>
  47 using namespace llvm;
  48
  49 #define DEBUG_TYPE "insert-gcov-profiling"
  50
  51 static cl::opt<std::string>
  52 DefaultGCOVVersion("default-gcov-version", cl::init("402*"), cl::Hidden,
  53                    cl::ValueRequired);
  54 static cl::opt<bool> DefaultExitBlockBeforeBody("gcov-exit-block-before-body",
  55                                                 cl::init(false), cl::Hidden);
  56
  57 GCOVOptions GCOVOptions::getDefault() {
  58   GCOVOptions Options;
  59   Options.EmitNotes = true;
  60   Options.EmitData = true;
  61   Options.UseCfgChecksum = false;
  62   Options.NoRedZone = false;
  63   Options.FunctionNamesInData = true;
  64   Options.ExitBlockBeforeBody = DefaultExitBlockBeforeBody;
  65
  66   if (DefaultGCOVVersion.size() != 4) {
  67     llvm::report_fatal_error(std::string("Invalid -default-gcov-version: ") +
  68                              DefaultGCOVVersion);
  69   }
  70   memcpy(Options.Version, DefaultGCOVVersion.c_str(), 4);
  71   return Options;
  72 }
  73
  74 namespace {
  75 class GCOVFunction;
  76
  77 class GCOVProfiler {
  78 public:
  79   GCOVProfiler() : GCOVProfiler(GCOVOptions::getDefault()) {}
  80   GCOVProfiler(const GCOVOptions &Opts) : Options(Opts) {
  81     assert((Options.EmitNotes || Options.EmitData) &&
  82            "GCOVProfiler asked to do nothing?");
  83     ReversedVersion[0] = Options.Version[3];
  84     ReversedVersion[1] = Options.Version[2];
  85     ReversedVersion[2] = Options.Version[1];
  86     ReversedVersion[3] = Options.Version[0];
  87     ReversedVersion[4] = '\0';
  88   }
  89   bool runOnModule(Module &M, const TargetLibraryInfo &TLI);
  90
  91 private:
  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   bool isFunctionInstrumented(const Function &F);
 100   std::vector<Regex> createRegexesFromString(StringRef RegexesStr);
 101   static bool doesFilenameMatchARegex(StringRef Filename,
 102                                       std::vector<Regex> &Regexes);
 103
 104   // Get pointers to the functions in the runtime library.
 105   FunctionCallee getStartFileFunc();
 106   FunctionCallee getEmitFunctionFunc();
 107   FunctionCallee getEmitArcsFunc();
 108   FunctionCallee getSummaryInfoFunc();
 109   FunctionCallee getEndFileFunc();
 110
 111   // Add the function to write out all our counters to the global destructor
 112   // list.
 113   Function *
 114   insertCounterWriteout(ArrayRef<std::pair<GlobalVariable *, MDNode *>>);
 115   Function *insertFlush(ArrayRef<std::pair<GlobalVariable *, MDNode *>>);
 116
 117   void AddFlushBeforeForkAndExec();
 118
 119   enum class GCovFileType { GCNO, GCDA };
 120   std::string mangleName(const DICompileUnit *CU, GCovFileType FileType);
 121
 122   GCOVOptions Options;
 123
 124   // Reversed, NUL-terminated copy of Options.Version.
 125   char ReversedVersion[5];
 126   // Checksum, produced by hash of EdgeDestinations
 127   SmallVector<uint32_t, 4> FileChecksums;
 128
 129   Module *M;
 130   const TargetLibraryInfo *TLI;
 131   LLVMContext *Ctx;
 132   SmallVector<std::unique_ptr<GCOVFunction>, 16> Funcs;
 133   std::vector<Regex> FilterRe;
 134   std::vector<Regex> ExcludeRe;
 135   StringMap<bool> InstrumentedFiles;
 136 };
 137
 138 class GCOVProfilerLegacyPass : public ModulePass {
 139 public:
 140   static char ID;
 141   GCOVProfilerLegacyPass()
 142       : GCOVProfilerLegacyPass(GCOVOptions::getDefault()) {}
 143   GCOVProfilerLegacyPass(const GCOVOptions &Opts)
 144       : ModulePass(ID), Profiler(Opts) {
 145     initializeGCOVProfilerLegacyPassPass(*PassRegistry::getPassRegistry());
 146   }
 147   StringRef getPassName() const override { return "GCOV Profiler"; }
 148
 149   bool runOnModule(Module &M) override {
 150     auto &TLI = getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
 151     return Profiler.runOnModule(M, TLI);
 152   }
 153
 154   void getAnalysisUsage(AnalysisUsage &AU) const override {
 155     AU.addRequired<TargetLibraryInfoWrapperPass>();
 156   }
 157
 158 private:
 159   GCOVProfiler Profiler;
 160 };
 161 }
 162
 163 char GCOVProfilerLegacyPass::ID = 0;
 164 INITIALIZE_PASS_BEGIN(
 165     GCOVProfilerLegacyPass, "insert-gcov-profiling",
 166     "Insert instrumentation for GCOV profiling", false, false)
 167 INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
 168 INITIALIZE_PASS_END(
 169     GCOVProfilerLegacyPass, "insert-gcov-profiling",
 170     "Insert instrumentation for GCOV profiling", false, false)
 171
 172 ModulePass *llvm::createGCOVProfilerPass(const GCOVOptions &Options) {
 173   return new GCOVProfilerLegacyPass(Options);
 174 }
 175
 176 static StringRef getFunctionName(const DISubprogram *SP) {
 177   if (!SP->getLinkageName().empty())
 178     return SP->getLinkageName();
 179   return SP->getName();
 180 }
 181
 182 /// Extract a filename for a DISubprogram.
 183 ///
 184 /// Prefer relative paths in the coverage notes. Clang also may split
 185 /// up absolute paths into a directory and filename component. When
 186 /// the relative path doesn't exist, reconstruct the absolute path.
 187 static SmallString<128> getFilename(const DISubprogram *SP) {
 188   SmallString<128> Path;
 189   StringRef RelPath = SP->getFilename();
 190   if (sys::fs::exists(RelPath))
 191     Path = RelPath;
 192   else
 193     sys::path::append(Path, SP->getDirectory(), SP->getFilename());
 194   return Path;
 195 }
 196
 197 namespace {
 198   class GCOVRecord {
 199    protected:
 200     static const char *const LinesTag;
 201     static const char *const FunctionTag;
 202     static const char *const BlockTag;
 203     static const char *const EdgeTag;
 204
 205     GCOVRecord() = default;
 206
 207     void writeBytes(const char *Bytes, int Size) {
 208       os->write(Bytes, Size);
 209     }
 210
 211     void write(uint32_t i) {
 212       writeBytes(reinterpret_cast<char*>(&i), 4);
 213     }
 214
 215     // Returns the length measured in 4-byte blocks that will be used to
 216     // represent this string in a GCOV file
 217     static unsigned lengthOfGCOVString(StringRef s) {
 218       // A GCOV string is a length, followed by a NUL, then between 0 and 3 NULs
 219       // padding out to the next 4-byte word. The length is measured in 4-byte
 220       // words including padding, not bytes of actual string.
 221       return (s.size() / 4) + 1;
 222     }
 223
 224     void writeGCOVString(StringRef s) {
 225       uint32_t Len = lengthOfGCOVString(s);
 226       write(Len);
 227       writeBytes(s.data(), s.size());
 228
 229       // Write 1 to 4 bytes of NUL padding.
 230       assert((unsigned)(4 - (s.size() % 4)) > 0);
 231       assert((unsigned)(4 - (s.size() % 4)) <= 4);
 232       writeBytes("\0\0\0\0", 4 - (s.size() % 4));
 233     }
 234
 235     raw_ostream *os;
 236   };
 237   const char *const GCOVRecord::LinesTag = "\0\0\x45\x01";
 238   const char *const GCOVRecord::FunctionTag = "\0\0\0\1";
 239   const char *const GCOVRecord::BlockTag = "\0\0\x41\x01";
 240   const char *const GCOVRecord::EdgeTag = "\0\0\x43\x01";
 241
 242   class GCOVFunction;
 243   class GCOVBlock;
 244
 245   // Constructed only by requesting it from a GCOVBlock, this object stores a
 246   // list of line numbers and a single filename, representing lines that belong
 247   // to the block.
 248   class GCOVLines : public GCOVRecord {
 249    public:
 250     void addLine(uint32_t Line) {
 251       assert(Line != 0 && "Line zero is not a valid real line number.");
 252       Lines.push_back(Line);
 253     }
 254
 255     uint32_t length() const {
 256       // Here 2 = 1 for string length + 1 for '0' id#.
 257       return lengthOfGCOVString(Filename) + 2 + Lines.size();
 258     }
 259
 260     void writeOut() {
 261       write(0);
 262       writeGCOVString(Filename);
 263       for (int i = 0, e = Lines.size(); i != e; ++i)
 264         write(Lines[i]);
 265     }
 266
 267     GCOVLines(StringRef F, raw_ostream *os)
 268       : Filename(F) {
 269       this->os = os;
 270     }
 271
 272    private:
 273     std::string Filename;
 274     SmallVector<uint32_t, 32> Lines;
 275   };
 276
 277
 278   // Represent a basic block in GCOV. Each block has a unique number in the
 279   // function, number of lines belonging to each block, and a set of edges to
 280   // other blocks.
 281   class GCOVBlock : public GCOVRecord {
 282    public:
 283     GCOVLines &getFile(StringRef Filename) {
 284       return LinesByFile.try_emplace(Filename, Filename, os).first->second;
 285     }
 286
 287     void addEdge(GCOVBlock &Successor) {
 288       OutEdges.push_back(&Successor);
 289     }
 290
 291     void writeOut() {
 292       uint32_t Len = 3;
 293       SmallVector<StringMapEntry<GCOVLines> *, 32> SortedLinesByFile;
 294       for (auto &I : LinesByFile) {
 295         Len += I.second.length();
 296         SortedLinesByFile.push_back(&I);
 297       }
 298
 299       writeBytes(LinesTag, 4);
 300       write(Len);
 301       write(Number);
 302
 303       llvm::sort(SortedLinesByFile, [](StringMapEntry<GCOVLines> *LHS,
 304                                        StringMapEntry<GCOVLines> *RHS) {
 305         return LHS->getKey() < RHS->getKey();
 306       });
 307       for (auto &I : SortedLinesByFile)
 308         I->getValue().writeOut();
 309       write(0);
 310       write(0);
 311     }
 312
 313     GCOVBlock(const GCOVBlock &RHS) : GCOVRecord(RHS), Number(RHS.Number) {
 314       // Only allow copy before edges and lines have been added. After that,
 315       // there are inter-block pointers (eg: edges) that won't take kindly to
 316       // blocks being copied or moved around.
 317       assert(LinesByFile.empty());
 318       assert(OutEdges.empty());
 319     }
 320
 321    private:
 322     friend class GCOVFunction;
 323
 324     GCOVBlock(uint32_t Number, raw_ostream *os)
 325         : Number(Number) {
 326       this->os = os;
 327     }
 328
 329     uint32_t Number;
 330     StringMap<GCOVLines> LinesByFile;
 331     SmallVector<GCOVBlock *, 4> OutEdges;
 332   };
 333
 334   // A function has a unique identifier, a checksum (we leave as zero) and a
 335   // set of blocks and a map of edges between blocks. This is the only GCOV
 336   // object users can construct, the blocks and lines will be rooted here.
 337   class GCOVFunction : public GCOVRecord {
 338    public:
 339      GCOVFunction(const DISubprogram *SP, Function *F, raw_ostream *os,
 340                   uint32_t Ident, bool UseCfgChecksum, bool ExitBlockBeforeBody)
 341          : SP(SP), Ident(Ident), UseCfgChecksum(UseCfgChecksum), CfgChecksum(0),
 342            ReturnBlock(1, os) {
 343       this->os = os;
 344
 345       LLVM_DEBUG(dbgs() << "Function: " << getFunctionName(SP) << "\n");
 346
 347       uint32_t i = 0;
 348       for (auto &BB : *F) {
 349         // Skip index 1 if it's assigned to the ReturnBlock.
 350         if (i == 1 && ExitBlockBeforeBody)
 351           ++i;
 352         Blocks.insert(std::make_pair(&BB, GCOVBlock(i++, os)));
 353       }
 354       if (!ExitBlockBeforeBody)
 355         ReturnBlock.Number = i;
 356
 357       std::string FunctionNameAndLine;
 358       raw_string_ostream FNLOS(FunctionNameAndLine);
 359       FNLOS << getFunctionName(SP) << SP->getLine();
 360       FNLOS.flush();
 361       FuncChecksum = hash_value(FunctionNameAndLine);
 362     }
 363
 364     GCOVBlock &getBlock(BasicBlock *BB) {
 365       return Blocks.find(BB)->second;
 366     }
 367
 368     GCOVBlock &getReturnBlock() {
 369       return ReturnBlock;
 370     }
 371
 372     std::string getEdgeDestinations() {
 373       std::string EdgeDestinations;
 374       raw_string_ostream EDOS(EdgeDestinations);
 375       Function *F = Blocks.begin()->first->getParent();
 376       for (BasicBlock &I : *F) {
 377         GCOVBlock &Block = getBlock(&I);
 378         for (int i = 0, e = Block.OutEdges.size(); i != e; ++i)
 379           EDOS << Block.OutEdges[i]->Number;
 380       }
 381       return EdgeDestinations;
 382     }
 383
 384     uint32_t getFuncChecksum() {
 385       return FuncChecksum;
 386     }
 387
 388     void setCfgChecksum(uint32_t Checksum) {
 389       CfgChecksum = Checksum;
 390     }
 391
 392     void writeOut() {
 393       writeBytes(FunctionTag, 4);
 394       SmallString<128> Filename = getFilename(SP);
 395       uint32_t BlockLen = 1 + 1 + 1 + lengthOfGCOVString(getFunctionName(SP)) +
 396                           1 + lengthOfGCOVString(Filename) + 1;
 397       if (UseCfgChecksum)
 398         ++BlockLen;
 399       write(BlockLen);
 400       write(Ident);
 401       write(FuncChecksum);
 402       if (UseCfgChecksum)
 403         write(CfgChecksum);
 404       writeGCOVString(getFunctionName(SP));
 405       writeGCOVString(Filename);
 406       write(SP->getLine());
 407
 408       // Emit count of blocks.
 409       writeBytes(BlockTag, 4);
 410       write(Blocks.size() + 1);
 411       for (int i = 0, e = Blocks.size() + 1; i != e; ++i) {
 412         write(0);  // No flags on our blocks.
 413       }
 414       LLVM_DEBUG(dbgs() << Blocks.size() << " blocks.\n");
 415
 416       // Emit edges between blocks.
 417       if (Blocks.empty()) return;
 418       Function *F = Blocks.begin()->first->getParent();
 419       for (BasicBlock &I : *F) {
 420         GCOVBlock &Block = getBlock(&I);
 421         if (Block.OutEdges.empty()) continue;
 422
 423         writeBytes(EdgeTag, 4);
 424         write(Block.OutEdges.size() * 2 + 1);
 425         write(Block.Number);
 426         for (int i = 0, e = Block.OutEdges.size(); i != e; ++i) {
 427           LLVM_DEBUG(dbgs() << Block.Number << " -> "
 428                             << Block.OutEdges[i]->Number << "\n");
 429           write(Block.OutEdges[i]->Number);
 430           write(0);  // no flags
 431         }
 432       }
 433
 434       // Emit lines for each block.
 435       for (BasicBlock &I : *F)
 436         getBlock(&I).writeOut();
 437     }
 438
 439    private:
 440      const DISubprogram *SP;
 441     uint32_t Ident;
 442     uint32_t FuncChecksum;
 443     bool UseCfgChecksum;
 444     uint32_t CfgChecksum;
 445     DenseMap<BasicBlock *, GCOVBlock> Blocks;
 446     GCOVBlock ReturnBlock;
 447   };
 448 }
 449
 450 // RegexesStr is a string containing differents regex separated by a semi-colon.
 451 // For example "foo\..*$;bar\..*$".
 452 std::vector<Regex> GCOVProfiler::createRegexesFromString(StringRef RegexesStr) {
 453   std::vector<Regex> Regexes;
 454   while (!RegexesStr.empty()) {
 455     std::pair<StringRef, StringRef> HeadTail = RegexesStr.split(';');
 456     if (!HeadTail.first.empty()) {
 457       Regex Re(HeadTail.first);
 458       std::string Err;
 459       if (!Re.isValid(Err)) {
 460         Ctx->emitError(Twine("Regex ") + HeadTail.first +
 461                        " is not valid: " + Err);
 462       }
 463       Regexes.emplace_back(std::move(Re));
 464     }
 465     RegexesStr = HeadTail.second;
 466   }
 467   return Regexes;
 468 }
 469
 470 bool GCOVProfiler::doesFilenameMatchARegex(StringRef Filename,
 471                                            std::vector<Regex> &Regexes) {
 472   for (Regex &Re : Regexes) {
 473     if (Re.match(Filename)) {
 474       return true;
 475     }
 476   }
 477   return false;
 478 }
 479
 480 bool GCOVProfiler::isFunctionInstrumented(const Function &F) {
 481   if (FilterRe.empty() && ExcludeRe.empty()) {
 482     return true;
 483   }
 484   SmallString<128> Filename = getFilename(F.getSubprogram());
 485   auto It = InstrumentedFiles.find(Filename);
 486   if (It != InstrumentedFiles.end()) {
 487     return It->second;
 488   }
 489
 490   SmallString<256> RealPath;
 491   StringRef RealFilename;
 492
 493   // Path can be
 494   // /usr/lib/gcc/x86_64-linux-gnu/8/../../../../include/c++/8/bits/*.h so for
 495   // such a case we must get the real_path.
 496   if (sys::fs::real_path(Filename, RealPath)) {
 497     // real_path can fail with path like "foo.c".
 498     RealFilename = Filename;
 499   } else {
 500     RealFilename = RealPath;
 501   }
 502
 503   bool ShouldInstrument;
 504   if (FilterRe.empty()) {
 505     ShouldInstrument = !doesFilenameMatchARegex(RealFilename, ExcludeRe);
 506   } else if (ExcludeRe.empty()) {
 507     ShouldInstrument = doesFilenameMatchARegex(RealFilename, FilterRe);
 508   } else {
 509     ShouldInstrument = doesFilenameMatchARegex(RealFilename, FilterRe) &&
 510                        !doesFilenameMatchARegex(RealFilename, ExcludeRe);
 511   }
 512   InstrumentedFiles[Filename] = ShouldInstrument;
 513   return ShouldInstrument;
 514 }
 515
 516 std::string GCOVProfiler::mangleName(const DICompileUnit *CU,
 517                                      GCovFileType OutputType) {
 518   bool Notes = OutputType == GCovFileType::GCNO;
 519
 520   if (NamedMDNode *GCov = M->getNamedMetadata("llvm.gcov")) {
 521     for (int i = 0, e = GCov->getNumOperands(); i != e; ++i) {
 522       MDNode *N = GCov->getOperand(i);
 523       bool ThreeElement = N->getNumOperands() == 3;
 524       if (!ThreeElement && N->getNumOperands() != 2)
 525         continue;
 526       if (dyn_cast<MDNode>(N->getOperand(ThreeElement ? 2 : 1)) != CU)
 527         continue;
 528
 529       if (ThreeElement) {
 530         // These nodes have no mangling to apply, it's stored mangled in the
 531         // bitcode.
 532         MDString *NotesFile = dyn_cast<MDString>(N->getOperand(0));
 533         MDString *DataFile = dyn_cast<MDString>(N->getOperand(1));
 534         if (!NotesFile || !DataFile)
 535           continue;
 536         return Notes ? NotesFile->getString() : DataFile->getString();
 537       }
 538
 539       MDString *GCovFile = dyn_cast<MDString>(N->getOperand(0));
 540       if (!GCovFile)
 541         continue;
 542
 543       SmallString<128> Filename = GCovFile->getString();
 544       sys::path::replace_extension(Filename, Notes ? "gcno" : "gcda");
 545       return Filename.str();
 546     }
 547   }
 548
 549   SmallString<128> Filename = CU->getFilename();
 550   sys::path::replace_extension(Filename, Notes ? "gcno" : "gcda");
 551   StringRef FName = sys::path::filename(Filename);
 552   SmallString<128> CurPath;
 553   if (sys::fs::current_path(CurPath)) return FName;
 554   sys::path::append(CurPath, FName);
 555   return CurPath.str();
 556 }
 557
 558 bool GCOVProfiler::runOnModule(Module &M, const TargetLibraryInfo &TLI) {
 559   this->M = &M;
 560   this->TLI = &TLI;
 561   Ctx = &M.getContext();
 562
 563   AddFlushBeforeForkAndExec();
 564
 565   FilterRe = createRegexesFromString(Options.Filter);
 566   ExcludeRe = createRegexesFromString(Options.Exclude);
 567
 568   if (Options.EmitNotes) emitProfileNotes();
 569   if (Options.EmitData) return emitProfileArcs();
 570   return false;
 571 }
 572
 573 PreservedAnalyses GCOVProfilerPass::run(Module &M,
 574                                         ModuleAnalysisManager &AM) {
 575
 576   GCOVProfiler Profiler(GCOVOpts);
 577
 578   auto &TLI = AM.getResult<TargetLibraryAnalysis>(M);
 579   if (!Profiler.runOnModule(M, TLI))
 580     return PreservedAnalyses::all();
 581
 582   return PreservedAnalyses::none();
 583 }
 584
 585 static bool functionHasLines(Function &F) {
 586   // Check whether this function actually has any source lines. Not only
 587   // do these waste space, they also can crash gcov.
 588   for (auto &BB : F) {
 589     for (auto &I : BB) {
 590       // Debug intrinsic locations correspond to the location of the
 591       // declaration, not necessarily any statements or expressions.
 592       if (isa<DbgInfoIntrinsic>(&I)) continue;
 593
 594       const DebugLoc &Loc = I.getDebugLoc();
 595       if (!Loc)
 596         continue;
 597
 598       // Artificial lines such as calls to the global constructors.
 599       if (Loc.getLine() == 0) continue;
 600
 601       return true;
 602     }
 603   }
 604   return false;
 605 }
 606
 607 static bool isUsingScopeBasedEH(Function &F) {
 608   if (!F.hasPersonalityFn()) return false;
 609
 610   EHPersonality Personality = classifyEHPersonality(F.getPersonalityFn());
 611   return isScopedEHPersonality(Personality);
 612 }
 613
 614 static bool shouldKeepInEntry(BasicBlock::iterator It) {
 615         if (isa<AllocaInst>(*It)) return true;
 616         if (isa<DbgInfoIntrinsic>(*It)) return true;
 617         if (auto *II = dyn_cast<IntrinsicInst>(It)) {
 618                 if (II->getIntrinsicID() == llvm::Intrinsic::localescape) return true;
 619         }
 620
 621         return false;
 622 }
 623
 624 void GCOVProfiler::AddFlushBeforeForkAndExec() {
 625   SmallVector<Instruction *, 2> ForkAndExecs;
 626   for (auto &F : M->functions()) {
 627     for (auto &I : instructions(F)) {
 628       if (CallInst *CI = dyn_cast<CallInst>(&I)) {
 629         if (Function *Callee = CI->getCalledFunction()) {
 630           LibFunc LF;
 631           if (TLI->getLibFunc(*Callee, LF) &&
 632               (LF == LibFunc_fork || LF == LibFunc_execl ||
 633                LF == LibFunc_execle || LF == LibFunc_execlp ||
 634                LF == LibFunc_execv || LF == LibFunc_execvp ||
 635                LF == LibFunc_execve || LF == LibFunc_execvpe ||
 636                LF == LibFunc_execvP)) {
 637             ForkAndExecs.push_back(&I);
 638           }
 639         }
 640       }
 641     }
 642   }
 643
 644   // We need to split the block after the fork/exec call
 645   // because else the counters for the lines after will be
 646   // the same as before the call.
 647   for (auto I : ForkAndExecs) {
 648     IRBuilder<> Builder(I);
 649     FunctionType *FTy = FunctionType::get(Builder.getVoidTy(), {}, false);
 650     FunctionCallee GCOVFlush = M->getOrInsertFunction("__gcov_flush", FTy);
 651     Builder.CreateCall(GCOVFlush);
 652     I->getParent()->splitBasicBlock(I);
 653   }
 654 }
 655
 656 void GCOVProfiler::emitProfileNotes() {
 657   NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
 658   if (!CU_Nodes) return;
 659
 660   for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
 661     // Each compile unit gets its own .gcno file. This means that whether we run
 662     // this pass over the original .o's as they're produced, or run it after
 663     // LTO, we'll generate the same .gcno files.
 664
 665     auto *CU = cast<DICompileUnit>(CU_Nodes->getOperand(i));
 666
 667     // Skip module skeleton (and module) CUs.
 668     if (CU->getDWOId())
 669       continue;
 670
 671     std::error_code EC;
 672     raw_fd_ostream out(mangleName(CU, GCovFileType::GCNO), EC,
 673                        sys::fs::OF_None);
 674     if (EC) {
 675       Ctx->emitError(Twine("failed to open coverage notes file for writing: ") +
 676                      EC.message());
 677       continue;
 678     }
 679
 680     std::string EdgeDestinations;
 681
 682     unsigned FunctionIdent = 0;
 683     for (auto &F : M->functions()) {
 684       DISubprogram *SP = F.getSubprogram();
 685       if (!SP) continue;
 686       if (!functionHasLines(F) || !isFunctionInstrumented(F))
 687         continue;
 688       // TODO: Functions using scope-based EH are currently not supported.
 689       if (isUsingScopeBasedEH(F)) continue;
 690
 691       // gcov expects every function to start with an entry block that has a
 692       // single successor, so split the entry block to make sure of that.
 693       BasicBlock &EntryBlock = F.getEntryBlock();
 694       BasicBlock::iterator It = EntryBlock.begin();
 695       while (shouldKeepInEntry(It))
 696         ++It;
 697       EntryBlock.splitBasicBlock(It);
 698
 699       Funcs.push_back(std::make_unique<GCOVFunction>(SP, &F, &out, FunctionIdent++,
 700                                                 Options.UseCfgChecksum,
 701                                                 Options.ExitBlockBeforeBody));
 702       GCOVFunction &Func = *Funcs.back();
 703
 704       // Add the function line number to the lines of the entry block
 705       // to have a counter for the function definition.
 706       uint32_t Line = SP->getLine();
 707       auto Filename = getFilename(SP);
 708       Func.getBlock(&EntryBlock).getFile(Filename).addLine(Line);
 709
 710       for (auto &BB : F) {
 711         GCOVBlock &Block = Func.getBlock(&BB);
 712         Instruction *TI = BB.getTerminator();
 713         if (int successors = TI->getNumSuccessors()) {
 714           for (int i = 0; i != successors; ++i) {
 715             Block.addEdge(Func.getBlock(TI->getSuccessor(i)));
 716           }
 717         } else if (isa<ReturnInst>(TI)) {
 718           Block.addEdge(Func.getReturnBlock());
 719         }
 720
 721         for (auto &I : BB) {
 722           // Debug intrinsic locations correspond to the location of the
 723           // declaration, not necessarily any statements or expressions.
 724           if (isa<DbgInfoIntrinsic>(&I)) continue;
 725
 726           const DebugLoc &Loc = I.getDebugLoc();
 727           if (!Loc)
 728             continue;
 729
 730           // Artificial lines such as calls to the global constructors.
 731           if (Loc.getLine() == 0 || Loc.isImplicitCode())
 732             continue;
 733
 734           if (Line == Loc.getLine()) continue;
 735           Line = Loc.getLine();
 736           if (SP != getDISubprogram(Loc.getScope()))
 737             continue;
 738
 739           GCOVLines &Lines = Block.getFile(Filename);
 740           Lines.addLine(Loc.getLine());
 741         }
 742         Line = 0;
 743       }
 744       EdgeDestinations += Func.getEdgeDestinations();
 745     }
 746
 747     FileChecksums.push_back(hash_value(EdgeDestinations));
 748     out.write("oncg", 4);
 749     out.write(ReversedVersion, 4);
 750     out.write(reinterpret_cast<char*>(&FileChecksums.back()), 4);
 751
 752     for (auto &Func : Funcs) {
 753       Func->setCfgChecksum(FileChecksums.back());
 754       Func->writeOut();
 755     }
 756
 757     out.write("\0\0\0\0\0\0\0\0", 8);  // EOF
 758     out.close();
 759   }
 760 }
 761
 762 bool GCOVProfiler::emitProfileArcs() {
 763   NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
 764   if (!CU_Nodes) return false;
 765
 766   bool Result = false;
 767   for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
 768     SmallVector<std::pair<GlobalVariable *, MDNode *>, 8> CountersBySP;
 769     for (auto &F : M->functions()) {
 770       DISubprogram *SP = F.getSubprogram();
 771       if (!SP) continue;
 772       if (!functionHasLines(F) || !isFunctionInstrumented(F))
 773         continue;
 774       // TODO: Functions using scope-based EH are currently not supported.
 775       if (isUsingScopeBasedEH(F)) continue;
 776       if (!Result) Result = true;
 777
 778       DenseMap<std::pair<BasicBlock *, BasicBlock *>, unsigned> EdgeToCounter;
 779       unsigned Edges = 0;
 780       for (auto &BB : F) {
 781         Instruction *TI = BB.getTerminator();
 782         if (isa<ReturnInst>(TI)) {
 783           EdgeToCounter[{&BB, nullptr}] = Edges++;
 784         } else {
 785           for (BasicBlock *Succ : successors(TI)) {
 786             EdgeToCounter[{&BB, Succ}] = Edges++;
 787           }
 788         }
 789       }
 790
 791       ArrayType *CounterTy =
 792         ArrayType::get(Type::getInt64Ty(*Ctx), Edges);
 793       GlobalVariable *Counters =
 794         new GlobalVariable(*M, CounterTy, false,
 795                            GlobalValue::InternalLinkage,
 796                            Constant::getNullValue(CounterTy),
 797                            "__llvm_gcov_ctr");
 798       CountersBySP.push_back(std::make_pair(Counters, SP));
 799
 800       // If a BB has several predecessors, use a PHINode to select
 801       // the correct counter.
 802       for (auto &BB : F) {
 803         const unsigned EdgeCount =
 804             std::distance(pred_begin(&BB), pred_end(&BB));
 805         if (EdgeCount) {
 806           // The phi node must be at the begin of the BB.
 807           IRBuilder<> BuilderForPhi(&*BB.begin());
 808           Type *Int64PtrTy = Type::getInt64PtrTy(*Ctx);
 809           PHINode *Phi = BuilderForPhi.CreatePHI(Int64PtrTy, EdgeCount);
 810           for (BasicBlock *Pred : predecessors(&BB)) {
 811             auto It = EdgeToCounter.find({Pred, &BB});
 812             assert(It != EdgeToCounter.end());
 813             const unsigned Edge = It->second;
 814             Value *EdgeCounter = BuilderForPhi.CreateConstInBoundsGEP2_64(
 815                 Counters->getValueType(), Counters, 0, Edge);
 816             Phi->addIncoming(EdgeCounter, Pred);
 817           }
 818
 819           // Skip phis, landingpads.
 820           IRBuilder<> Builder(&*BB.getFirstInsertionPt());
 821           Value *Count = Builder.CreateLoad(Builder.getInt64Ty(), Phi);
 822           Count = Builder.CreateAdd(Count, Builder.getInt64(1));
 823           Builder.CreateStore(Count, Phi);
 824
 825           Instruction *TI = BB.getTerminator();
 826           if (isa<ReturnInst>(TI)) {
 827             auto It = EdgeToCounter.find({&BB, nullptr});
 828             assert(It != EdgeToCounter.end());
 829             const unsigned Edge = It->second;
 830             Value *Counter = Builder.CreateConstInBoundsGEP2_64(
 831                 Counters->getValueType(), Counters, 0, Edge);
 832             Value *Count = Builder.CreateLoad(Builder.getInt64Ty(), Counter);
 833             Count = Builder.CreateAdd(Count, Builder.getInt64(1));
 834             Builder.CreateStore(Count, Counter);
 835           }
 836         }
 837       }
 838     }
 839
 840     Function *WriteoutF = insertCounterWriteout(CountersBySP);
 841     Function *FlushF = insertFlush(CountersBySP);
 842
 843     // Create a small bit of code that registers the "__llvm_gcov_writeout" to
 844     // be executed at exit and the "__llvm_gcov_flush" function to be executed
 845     // when "__gcov_flush" is called.
 846     FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
 847     Function *F = Function::Create(FTy, GlobalValue::InternalLinkage,
 848                                    "__llvm_gcov_init", M);
 849     F->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
 850     F->setLinkage(GlobalValue::InternalLinkage);
 851     F->addFnAttr(Attribute::NoInline);
 852     if (Options.NoRedZone)
 853       F->addFnAttr(Attribute::NoRedZone);
 854
 855     BasicBlock *BB = BasicBlock::Create(*Ctx, "entry", F);
 856     IRBuilder<> Builder(BB);
 857
 858     FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
 859     Type *Params[] = {
 860       PointerType::get(FTy, 0),
 861       PointerType::get(FTy, 0)
 862     };
 863     FTy = FunctionType::get(Builder.getVoidTy(), Params, false);
 864
 865     // Initialize the environment and register the local writeout and flush
 866     // functions.
 867     FunctionCallee GCOVInit = M->getOrInsertFunction("llvm_gcov_init", FTy);
 868     Builder.CreateCall(GCOVInit, {WriteoutF, FlushF});
 869     Builder.CreateRetVoid();
 870
 871     appendToGlobalCtors(*M, F, 0);
 872   }
 873
 874   return Result;
 875 }
 876
 877 FunctionCallee GCOVProfiler::getStartFileFunc() {
 878   Type *Args[] = {
 879     Type::getInt8PtrTy(*Ctx),  // const char *orig_filename
 880     Type::getInt8PtrTy(*Ctx),  // const char version[4]
 881     Type::getInt32Ty(*Ctx),    // uint32_t checksum
 882   };
 883   FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false);
 884   AttributeList AL;
 885   if (auto AK = TLI->getExtAttrForI32Param(false))
 886     AL = AL.addParamAttribute(*Ctx, 2, AK);
 887   FunctionCallee Res = M->getOrInsertFunction("llvm_gcda_start_file", FTy, AL);
 888   return Res;
 889 }
 890
 891 FunctionCallee GCOVProfiler::getEmitFunctionFunc() {
 892   Type *Args[] = {
 893     Type::getInt32Ty(*Ctx),    // uint32_t ident
 894     Type::getInt8PtrTy(*Ctx),  // const char *function_name
 895     Type::getInt32Ty(*Ctx),    // uint32_t func_checksum
 896     Type::getInt8Ty(*Ctx),     // uint8_t use_extra_checksum
 897     Type::getInt32Ty(*Ctx),    // uint32_t cfg_checksum
 898   };
 899   FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false);
 900   AttributeList AL;
 901   if (auto AK = TLI->getExtAttrForI32Param(false)) {
 902     AL = AL.addParamAttribute(*Ctx, 0, AK);
 903     AL = AL.addParamAttribute(*Ctx, 2, AK);
 904     AL = AL.addParamAttribute(*Ctx, 3, AK);
 905     AL = AL.addParamAttribute(*Ctx, 4, AK);
 906   }
 907   return M->getOrInsertFunction("llvm_gcda_emit_function", FTy);
 908 }
 909
 910 FunctionCallee GCOVProfiler::getEmitArcsFunc() {
 911   Type *Args[] = {
 912     Type::getInt32Ty(*Ctx),     // uint32_t num_counters
 913     Type::getInt64PtrTy(*Ctx),  // uint64_t *counters
 914   };
 915   FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false);
 916   AttributeList AL;
 917   if (auto AK = TLI->getExtAttrForI32Param(false))
 918     AL = AL.addParamAttribute(*Ctx, 0, AK);
 919   return M->getOrInsertFunction("llvm_gcda_emit_arcs", FTy, AL);
 920 }
 921
 922 FunctionCallee GCOVProfiler::getSummaryInfoFunc() {
 923   FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
 924   return M->getOrInsertFunction("llvm_gcda_summary_info", FTy);
 925 }
 926
 927 FunctionCallee GCOVProfiler::getEndFileFunc() {
 928   FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
 929   return M->getOrInsertFunction("llvm_gcda_end_file", FTy);
 930 }
 931
 932 Function *GCOVProfiler::insertCounterWriteout(
 933     ArrayRef<std::pair<GlobalVariable *, MDNode *> > CountersBySP) {
 934   FunctionType *WriteoutFTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
 935   Function *WriteoutF = M->getFunction("__llvm_gcov_writeout");
 936   if (!WriteoutF)
 937     WriteoutF = Function::Create(WriteoutFTy, GlobalValue::InternalLinkage,
 938                                  "__llvm_gcov_writeout", M);
 939   WriteoutF->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
 940   WriteoutF->addFnAttr(Attribute::NoInline);
 941   if (Options.NoRedZone)
 942     WriteoutF->addFnAttr(Attribute::NoRedZone);
 943
 944   BasicBlock *BB = BasicBlock::Create(*Ctx, "entry", WriteoutF);
 945   IRBuilder<> Builder(BB);
 946
 947   FunctionCallee StartFile = getStartFileFunc();
 948   FunctionCallee EmitFunction = getEmitFunctionFunc();
 949   FunctionCallee EmitArcs = getEmitArcsFunc();
 950   FunctionCallee SummaryInfo = getSummaryInfoFunc();
 951   FunctionCallee EndFile = getEndFileFunc();
 952
 953   NamedMDNode *CUNodes = M->getNamedMetadata("llvm.dbg.cu");
 954   if (!CUNodes) {
 955     Builder.CreateRetVoid();
 956     return WriteoutF;
 957   }
 958
 959   // Collect the relevant data into a large constant data structure that we can
 960   // walk to write out everything.
 961   StructType *StartFileCallArgsTy = StructType::create(
 962       {Builder.getInt8PtrTy(), Builder.getInt8PtrTy(), Builder.getInt32Ty()});
 963   StructType *EmitFunctionCallArgsTy = StructType::create(
 964       {Builder.getInt32Ty(), Builder.getInt8PtrTy(), Builder.getInt32Ty(),
 965        Builder.getInt8Ty(), Builder.getInt32Ty()});
 966   StructType *EmitArcsCallArgsTy = StructType::create(
 967       {Builder.getInt32Ty(), Builder.getInt64Ty()->getPointerTo()});
 968   StructType *FileInfoTy =
 969       StructType::create({StartFileCallArgsTy, Builder.getInt32Ty(),
 970                           EmitFunctionCallArgsTy->getPointerTo(),
 971                           EmitArcsCallArgsTy->getPointerTo()});
 972
 973   Constant *Zero32 = Builder.getInt32(0);
 974   // Build an explicit array of two zeros for use in ConstantExpr GEP building.
 975   Constant *TwoZero32s[] = {Zero32, Zero32};
 976
 977   SmallVector<Constant *, 8> FileInfos;
 978   for (int i : llvm::seq<int>(0, CUNodes->getNumOperands())) {
 979     auto *CU = cast<DICompileUnit>(CUNodes->getOperand(i));
 980
 981     // Skip module skeleton (and module) CUs.
 982     if (CU->getDWOId())
 983       continue;
 984
 985     std::string FilenameGcda = mangleName(CU, GCovFileType::GCDA);
 986     uint32_t CfgChecksum = FileChecksums.empty() ? 0 : FileChecksums[i];
 987     auto *StartFileCallArgs = ConstantStruct::get(
 988         StartFileCallArgsTy, {Builder.CreateGlobalStringPtr(FilenameGcda),
 989                               Builder.CreateGlobalStringPtr(ReversedVersion),
 990                               Builder.getInt32(CfgChecksum)});
 991
 992     SmallVector<Constant *, 8> EmitFunctionCallArgsArray;
 993     SmallVector<Constant *, 8> EmitArcsCallArgsArray;
 994     for (int j : llvm::seq<int>(0, CountersBySP.size())) {
 995       auto *SP = cast_or_null<DISubprogram>(CountersBySP[j].second);
 996       uint32_t FuncChecksum = Funcs.empty() ? 0 : Funcs[j]->getFuncChecksum();
 997       EmitFunctionCallArgsArray.push_back(ConstantStruct::get(
 998           EmitFunctionCallArgsTy,
 999           {Builder.getInt32(j),
1000            Options.FunctionNamesInData
1001                ? Builder.CreateGlobalStringPtr(getFunctionName(SP))
1002                : Constant::getNullValue(Builder.getInt8PtrTy()),
1003            Builder.getInt32(FuncChecksum),
1004            Builder.getInt8(Options.UseCfgChecksum),
1005            Builder.getInt32(CfgChecksum)}));
1006
1007       GlobalVariable *GV = CountersBySP[j].first;
1008       unsigned Arcs = cast<ArrayType>(GV->getValueType())->getNumElements();
1009       EmitArcsCallArgsArray.push_back(ConstantStruct::get(
1010           EmitArcsCallArgsTy,
1011           {Builder.getInt32(Arcs), ConstantExpr::getInBoundsGetElementPtr(
1012                                        GV->getValueType(), GV, TwoZero32s)}));
1013     }
1014     // Create global arrays for the two emit calls.
1015     int CountersSize = CountersBySP.size();
1016     assert(CountersSize == (int)EmitFunctionCallArgsArray.size() &&
1017            "Mismatched array size!");
1018     assert(CountersSize == (int)EmitArcsCallArgsArray.size() &&
1019            "Mismatched array size!");
1020     auto *EmitFunctionCallArgsArrayTy =
1021         ArrayType::get(EmitFunctionCallArgsTy, CountersSize);
1022     auto *EmitFunctionCallArgsArrayGV = new GlobalVariable(
1023         *M, EmitFunctionCallArgsArrayTy, /*isConstant*/ true,
1024         GlobalValue::InternalLinkage,
1025         ConstantArray::get(EmitFunctionCallArgsArrayTy,
1026                            EmitFunctionCallArgsArray),
1027         Twine("__llvm_internal_gcov_emit_function_args.") + Twine(i));
1028     auto *EmitArcsCallArgsArrayTy =
1029         ArrayType::get(EmitArcsCallArgsTy, CountersSize);
1030     EmitFunctionCallArgsArrayGV->setUnnamedAddr(
1031         GlobalValue::UnnamedAddr::Global);
1032     auto *EmitArcsCallArgsArrayGV = new GlobalVariable(
1033         *M, EmitArcsCallArgsArrayTy, /*isConstant*/ true,
1034         GlobalValue::InternalLinkage,
1035         ConstantArray::get(EmitArcsCallArgsArrayTy, EmitArcsCallArgsArray),
1036         Twine("__llvm_internal_gcov_emit_arcs_args.") + Twine(i));
1037     EmitArcsCallArgsArrayGV->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
1038
1039     FileInfos.push_back(ConstantStruct::get(
1040         FileInfoTy,
1041         {StartFileCallArgs, Builder.getInt32(CountersSize),
1042          ConstantExpr::getInBoundsGetElementPtr(EmitFunctionCallArgsArrayTy,
1043                                                 EmitFunctionCallArgsArrayGV,
1044                                                 TwoZero32s),
1045          ConstantExpr::getInBoundsGetElementPtr(
1046              EmitArcsCallArgsArrayTy, EmitArcsCallArgsArrayGV, TwoZero32s)}));
1047   }
1048
1049   // If we didn't find anything to actually emit, bail on out.
1050   if (FileInfos.empty()) {
1051     Builder.CreateRetVoid();
1052     return WriteoutF;
1053   }
1054
1055   // To simplify code, we cap the number of file infos we write out to fit
1056   // easily in a 32-bit signed integer. This gives consistent behavior between
1057   // 32-bit and 64-bit systems without requiring (potentially very slow) 64-bit
1058   // operations on 32-bit systems. It also seems unreasonable to try to handle
1059   // more than 2 billion files.
1060   if ((int64_t)FileInfos.size() > (int64_t)INT_MAX)
1061     FileInfos.resize(INT_MAX);
1062
1063   // Create a global for the entire data structure so we can walk it more
1064   // easily.
1065   auto *FileInfoArrayTy = ArrayType::get(FileInfoTy, FileInfos.size());
1066   auto *FileInfoArrayGV = new GlobalVariable(
1067       *M, FileInfoArrayTy, /*isConstant*/ true, GlobalValue::InternalLinkage,
1068       ConstantArray::get(FileInfoArrayTy, FileInfos),
1069       "__llvm_internal_gcov_emit_file_info");
1070   FileInfoArrayGV->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
1071
1072   // Create the CFG for walking this data structure.
1073   auto *FileLoopHeader =
1074       BasicBlock::Create(*Ctx, "file.loop.header", WriteoutF);
1075   auto *CounterLoopHeader =
1076       BasicBlock::Create(*Ctx, "counter.loop.header", WriteoutF);
1077   auto *FileLoopLatch = BasicBlock::Create(*Ctx, "file.loop.latch", WriteoutF);
1078   auto *ExitBB = BasicBlock::Create(*Ctx, "exit", WriteoutF);
1079
1080   // We always have at least one file, so just branch to the header.
1081   Builder.CreateBr(FileLoopHeader);
1082
1083   // The index into the files structure is our loop induction variable.
1084   Builder.SetInsertPoint(FileLoopHeader);
1085   PHINode *IV =
1086       Builder.CreatePHI(Builder.getInt32Ty(), /*NumReservedValues*/ 2);
1087   IV->addIncoming(Builder.getInt32(0), BB);
1088   auto *FileInfoPtr = Builder.CreateInBoundsGEP(
1089       FileInfoArrayTy, FileInfoArrayGV, {Builder.getInt32(0), IV});
1090   auto *StartFileCallArgsPtr =
1091       Builder.CreateStructGEP(FileInfoTy, FileInfoPtr, 0);
1092   auto *StartFileCall = Builder.CreateCall(
1093       StartFile,
1094       {Builder.CreateLoad(StartFileCallArgsTy->getElementType(0),
1095                           Builder.CreateStructGEP(StartFileCallArgsTy,
1096                                                   StartFileCallArgsPtr, 0)),
1097        Builder.CreateLoad(StartFileCallArgsTy->getElementType(1),
1098                           Builder.CreateStructGEP(StartFileCallArgsTy,
1099                                                   StartFileCallArgsPtr, 1)),
1100        Builder.CreateLoad(StartFileCallArgsTy->getElementType(2),
1101                           Builder.CreateStructGEP(StartFileCallArgsTy,
1102                                                   StartFileCallArgsPtr, 2))});
1103   if (auto AK = TLI->getExtAttrForI32Param(false))
1104     StartFileCall->addParamAttr(2, AK);
1105   auto *NumCounters =
1106       Builder.CreateLoad(FileInfoTy->getElementType(1),
1107                          Builder.CreateStructGEP(FileInfoTy, FileInfoPtr, 1));
1108   auto *EmitFunctionCallArgsArray =
1109       Builder.CreateLoad(FileInfoTy->getElementType(2),
1110                          Builder.CreateStructGEP(FileInfoTy, FileInfoPtr, 2));
1111   auto *EmitArcsCallArgsArray =
1112       Builder.CreateLoad(FileInfoTy->getElementType(3),
1113                          Builder.CreateStructGEP(FileInfoTy, FileInfoPtr, 3));
1114   auto *EnterCounterLoopCond =
1115       Builder.CreateICmpSLT(Builder.getInt32(0), NumCounters);
1116   Builder.CreateCondBr(EnterCounterLoopCond, CounterLoopHeader, FileLoopLatch);
1117
1118   Builder.SetInsertPoint(CounterLoopHeader);
1119   auto *JV = Builder.CreatePHI(Builder.getInt32Ty(), /*NumReservedValues*/ 2);
1120   JV->addIncoming(Builder.getInt32(0), FileLoopHeader);
1121   auto *EmitFunctionCallArgsPtr = Builder.CreateInBoundsGEP(
1122       EmitFunctionCallArgsTy, EmitFunctionCallArgsArray, JV);
1123   auto *EmitFunctionCall = Builder.CreateCall(
1124       EmitFunction,
1125       {Builder.CreateLoad(EmitFunctionCallArgsTy->getElementType(0),
1126                           Builder.CreateStructGEP(EmitFunctionCallArgsTy,
1127                                                   EmitFunctionCallArgsPtr, 0)),
1128        Builder.CreateLoad(EmitFunctionCallArgsTy->getElementType(1),
1129                           Builder.CreateStructGEP(EmitFunctionCallArgsTy,
1130                                                   EmitFunctionCallArgsPtr, 1)),
1131        Builder.CreateLoad(EmitFunctionCallArgsTy->getElementType(2),
1132                           Builder.CreateStructGEP(EmitFunctionCallArgsTy,
1133                                                   EmitFunctionCallArgsPtr, 2)),
1134        Builder.CreateLoad(EmitFunctionCallArgsTy->getElementType(3),
1135                           Builder.CreateStructGEP(EmitFunctionCallArgsTy,
1136                                                   EmitFunctionCallArgsPtr, 3)),
1137        Builder.CreateLoad(EmitFunctionCallArgsTy->getElementType(4),
1138                           Builder.CreateStructGEP(EmitFunctionCallArgsTy,
1139                                                   EmitFunctionCallArgsPtr,
1140                                                   4))});
1141   if (auto AK = TLI->getExtAttrForI32Param(false)) {
1142     EmitFunctionCall->addParamAttr(0, AK);
1143     EmitFunctionCall->addParamAttr(2, AK);
1144     EmitFunctionCall->addParamAttr(3, AK);
1145     EmitFunctionCall->addParamAttr(4, AK);
1146   }
1147   auto *EmitArcsCallArgsPtr =
1148       Builder.CreateInBoundsGEP(EmitArcsCallArgsTy, EmitArcsCallArgsArray, JV);
1149   auto *EmitArcsCall = Builder.CreateCall(
1150       EmitArcs,
1151       {Builder.CreateLoad(
1152            EmitArcsCallArgsTy->getElementType(0),
1153            Builder.CreateStructGEP(EmitArcsCallArgsTy, EmitArcsCallArgsPtr, 0)),
1154        Builder.CreateLoad(EmitArcsCallArgsTy->getElementType(1),
1155                           Builder.CreateStructGEP(EmitArcsCallArgsTy,
1156                                                   EmitArcsCallArgsPtr, 1))});
1157   if (auto AK = TLI->getExtAttrForI32Param(false))
1158     EmitArcsCall->addParamAttr(0, AK);
1159   auto *NextJV = Builder.CreateAdd(JV, Builder.getInt32(1));
1160   auto *CounterLoopCond = Builder.CreateICmpSLT(NextJV, NumCounters);
1161   Builder.CreateCondBr(CounterLoopCond, CounterLoopHeader, FileLoopLatch);
1162   JV->addIncoming(NextJV, CounterLoopHeader);
1163
1164   Builder.SetInsertPoint(FileLoopLatch);
1165   Builder.CreateCall(SummaryInfo, {});
1166   Builder.CreateCall(EndFile, {});
1167   auto *NextIV = Builder.CreateAdd(IV, Builder.getInt32(1));
1168   auto *FileLoopCond =
1169       Builder.CreateICmpSLT(NextIV, Builder.getInt32(FileInfos.size()));
1170   Builder.CreateCondBr(FileLoopCond, FileLoopHeader, ExitBB);
1171   IV->addIncoming(NextIV, FileLoopLatch);
1172
1173   Builder.SetInsertPoint(ExitBB);
1174   Builder.CreateRetVoid();
1175
1176   return WriteoutF;
1177 }
1178
1179 Function *GCOVProfiler::
1180 insertFlush(ArrayRef<std::pair<GlobalVariable*, MDNode*> > CountersBySP) {
1181   FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
1182   Function *FlushF = M->getFunction("__llvm_gcov_flush");
1183   if (!FlushF)
1184     FlushF = Function::Create(FTy, GlobalValue::InternalLinkage,
1185                               "__llvm_gcov_flush", M);
1186   else
1187     FlushF->setLinkage(GlobalValue::InternalLinkage);
1188   FlushF->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
1189   FlushF->addFnAttr(Attribute::NoInline);
1190   if (Options.NoRedZone)
1191     FlushF->addFnAttr(Attribute::NoRedZone);
1192
1193   BasicBlock *Entry = BasicBlock::Create(*Ctx, "entry", FlushF);
1194
1195   // Write out the current counters.
1196   Function *WriteoutF = M->getFunction("__llvm_gcov_writeout");
1197   assert(WriteoutF && "Need to create the writeout function first!");
1198
1199   IRBuilder<> Builder(Entry);
1200   Builder.CreateCall(WriteoutF, {});
1201
1202   // Zero out the counters.
1203   for (const auto &I : CountersBySP) {
1204     GlobalVariable *GV = I.first;
1205     Constant *Null = Constant::getNullValue(GV->getValueType());
1206     Builder.CreateStore(Null, GV);
1207   }
1208
1209   Type *RetTy = FlushF->getReturnType();
1210   if (RetTy == Type::getVoidTy(*Ctx))
1211     Builder.CreateRetVoid();
1212   else if (RetTy->isIntegerTy())
1213     // Used if __llvm_gcov_flush was implicitly declared.
1214     Builder.CreateRet(ConstantInt::get(RetTy, 0));
1215   else
1216     report_fatal_error("invalid return type for __llvm_gcov_flush");
1217
1218   return FlushF;
1219 }