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
  90   runOnModule(Module &M,
  91               std::function<const TargetLibraryInfo &(Function &F)> GetTLI);
  92
  93 private:
  94   // Create the .gcno files for the Module based on DebugInfo.
  95   void emitProfileNotes();
  96
  97   // Modify the program to track transitions along edges and call into the
  98   // profiling runtime to emit .gcda files when run.
  99   bool emitProfileArcs();
 100
 101   bool isFunctionInstrumented(const Function &F);
 102   std::vector<Regex> createRegexesFromString(StringRef RegexesStr);
 103   static bool doesFilenameMatchARegex(StringRef Filename,
 104                                       std::vector<Regex> &Regexes);
 105
 106   // Get pointers to the functions in the runtime library.
 107   FunctionCallee getStartFileFunc(const TargetLibraryInfo *TLI);
 108   FunctionCallee getEmitFunctionFunc(const TargetLibraryInfo *TLI);
 109   FunctionCallee getEmitArcsFunc(const TargetLibraryInfo *TLI);
 110   FunctionCallee getSummaryInfoFunc();
 111   FunctionCallee getEndFileFunc();
 112
 113   // Add the function to write out all our counters to the global destructor
 114   // list.
 115   Function *
 116   insertCounterWriteout(ArrayRef<std::pair<GlobalVariable *, MDNode *>>);
 117   Function *insertFlush(ArrayRef<std::pair<GlobalVariable *, MDNode *>>);
 118
 119   void AddFlushBeforeForkAndExec();
 120
 121   enum class GCovFileType { GCNO, GCDA };
 122   std::string mangleName(const DICompileUnit *CU, GCovFileType FileType);
 123
 124   GCOVOptions Options;
 125
 126   // Reversed, NUL-terminated copy of Options.Version.
 127   char ReversedVersion[5];
 128   // Checksum, produced by hash of EdgeDestinations
 129   SmallVector<uint32_t, 4> FileChecksums;
 130
 131   Module *M;
 132   std::function<const TargetLibraryInfo &(Function &F)> GetTLI;
 133   LLVMContext *Ctx;
 134   SmallVector<std::unique_ptr<GCOVFunction>, 16> Funcs;
 135   std::vector<Regex> FilterRe;
 136   std::vector<Regex> ExcludeRe;
 137   StringMap<bool> InstrumentedFiles;
 138 };
 139
 140 class GCOVProfilerLegacyPass : public ModulePass {
 141 public:
 142   static char ID;
 143   GCOVProfilerLegacyPass()
 144       : GCOVProfilerLegacyPass(GCOVOptions::getDefault()) {}
 145   GCOVProfilerLegacyPass(const GCOVOptions &Opts)
 146       : ModulePass(ID), Profiler(Opts) {
 147     initializeGCOVProfilerLegacyPassPass(*PassRegistry::getPassRegistry());
 148   }
 149   StringRef getPassName() const override { return "GCOV Profiler"; }
 150
 151   bool runOnModule(Module &M) override {
 152     return Profiler.runOnModule(M, [this](Function &F) -> TargetLibraryInfo & {
 153       return getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(F);
 154     });
 155   }
 156
 157   void getAnalysisUsage(AnalysisUsage &AU) const override {
 158     AU.addRequired<TargetLibraryInfoWrapperPass>();
 159   }
 160
 161 private:
 162   GCOVProfiler Profiler;
 163 };
 164 }
 165
 166 char GCOVProfilerLegacyPass::ID = 0;
 167 INITIALIZE_PASS_BEGIN(
 168     GCOVProfilerLegacyPass, "insert-gcov-profiling",
 169     "Insert instrumentation for GCOV profiling", false, false)
 170 INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
 171 INITIALIZE_PASS_END(
 172     GCOVProfilerLegacyPass, "insert-gcov-profiling",
 173     "Insert instrumentation for GCOV profiling", false, false)
 174
 175 ModulePass *llvm::createGCOVProfilerPass(const GCOVOptions &Options) {
 176   return new GCOVProfilerLegacyPass(Options);
 177 }
 178
 179 static StringRef getFunctionName(const DISubprogram *SP) {
 180   if (!SP->getLinkageName().empty())
 181     return SP->getLinkageName();
 182   return SP->getName();
 183 }
 184
 185 /// Extract a filename for a DISubprogram.
 186 ///
 187 /// Prefer relative paths in the coverage notes. Clang also may split
 188 /// up absolute paths into a directory and filename component. When
 189 /// the relative path doesn't exist, reconstruct the absolute path.
 190 static SmallString<128> getFilename(const DISubprogram *SP) {
 191   SmallString<128> Path;
 192   StringRef RelPath = SP->getFilename();
 193   if (sys::fs::exists(RelPath))
 194     Path = RelPath;
 195   else
 196     sys::path::append(Path, SP->getDirectory(), SP->getFilename());
 197   return Path;
 198 }
 199
 200 namespace {
 201   class GCOVRecord {
 202    protected:
 203     static const char *const LinesTag;
 204     static const char *const FunctionTag;
 205     static const char *const BlockTag;
 206     static const char *const EdgeTag;
 207
 208     GCOVRecord() = default;
 209
 210     void writeBytes(const char *Bytes, int Size) {
 211       os->write(Bytes, Size);
 212     }
 213
 214     void write(uint32_t i) {
 215       writeBytes(reinterpret_cast<char*>(&i), 4);
 216     }
 217
 218     // Returns the length measured in 4-byte blocks that will be used to
 219     // represent this string in a GCOV file
 220     static unsigned lengthOfGCOVString(StringRef s) {
 221       // A GCOV string is a length, followed by a NUL, then between 0 and 3 NULs
 222       // padding out to the next 4-byte word. The length is measured in 4-byte
 223       // words including padding, not bytes of actual string.
 224       return (s.size() / 4) + 1;
 225     }
 226
 227     void writeGCOVString(StringRef s) {
 228       uint32_t Len = lengthOfGCOVString(s);
 229       write(Len);
 230       writeBytes(s.data(), s.size());
 231
 232       // Write 1 to 4 bytes of NUL padding.
 233       assert((unsigned)(4 - (s.size() % 4)) > 0);
 234       assert((unsigned)(4 - (s.size() % 4)) <= 4);
 235       writeBytes("\0\0\0\0", 4 - (s.size() % 4));
 236     }
 237
 238     raw_ostream *os;
 239   };
 240   const char *const GCOVRecord::LinesTag = "\0\0\x45\x01";
 241   const char *const GCOVRecord::FunctionTag = "\0\0\0\1";
 242   const char *const GCOVRecord::BlockTag = "\0\0\x41\x01";
 243   const char *const GCOVRecord::EdgeTag = "\0\0\x43\x01";
 244
 245   class GCOVFunction;
 246   class GCOVBlock;
 247
 248   // Constructed only by requesting it from a GCOVBlock, this object stores a
 249   // list of line numbers and a single filename, representing lines that belong
 250   // to the block.
 251   class GCOVLines : public GCOVRecord {
 252    public:
 253     void addLine(uint32_t Line) {
 254       assert(Line != 0 && "Line zero is not a valid real line number.");
 255       Lines.push_back(Line);
 256     }
 257
 258     uint32_t length() const {
 259       // Here 2 = 1 for string length + 1 for '0' id#.
 260       return lengthOfGCOVString(Filename) + 2 + Lines.size();
 261     }
 262
 263     void writeOut() {
 264       write(0);
 265       writeGCOVString(Filename);
 266       for (int i = 0, e = Lines.size(); i != e; ++i)
 267         write(Lines[i]);
 268     }
 269
 270     GCOVLines(StringRef F, raw_ostream *os)
 271       : Filename(F) {
 272       this->os = os;
 273     }
 274
 275    private:
 276     std::string Filename;
 277     SmallVector<uint32_t, 32> Lines;
 278   };
 279
 280
 281   // Represent a basic block in GCOV. Each block has a unique number in the
 282   // function, number of lines belonging to each block, and a set of edges to
 283   // other blocks.
 284   class GCOVBlock : public GCOVRecord {
 285    public:
 286     GCOVLines &getFile(StringRef Filename) {
 287       return LinesByFile.try_emplace(Filename, Filename, os).first->second;
 288     }
 289
 290     void addEdge(GCOVBlock &Successor) {
 291       OutEdges.push_back(&Successor);
 292     }
 293
 294     void writeOut() {
 295       uint32_t Len = 3;
 296       SmallVector<StringMapEntry<GCOVLines> *, 32> SortedLinesByFile;
 297       for (auto &I : LinesByFile) {
 298         Len += I.second.length();
 299         SortedLinesByFile.push_back(&I);
 300       }
 301
 302       writeBytes(LinesTag, 4);
 303       write(Len);
 304       write(Number);
 305
 306       llvm::sort(SortedLinesByFile, [](StringMapEntry<GCOVLines> *LHS,
 307                                        StringMapEntry<GCOVLines> *RHS) {
 308         return LHS->getKey() < RHS->getKey();
 309       });
 310       for (auto &I : SortedLinesByFile)
 311         I->getValue().writeOut();
 312       write(0);
 313       write(0);
 314     }
 315
 316     GCOVBlock(const GCOVBlock &RHS) : GCOVRecord(RHS), Number(RHS.Number) {
 317       // Only allow copy before edges and lines have been added. After that,
 318       // there are inter-block pointers (eg: edges) that won't take kindly to
 319       // blocks being copied or moved around.
 320       assert(LinesByFile.empty());
 321       assert(OutEdges.empty());
 322     }
 323
 324    private:
 325     friend class GCOVFunction;
 326
 327     GCOVBlock(uint32_t Number, raw_ostream *os)
 328         : Number(Number) {
 329       this->os = os;
 330     }
 331
 332     uint32_t Number;
 333     StringMap<GCOVLines> LinesByFile;
 334     SmallVector<GCOVBlock *, 4> OutEdges;
 335   };
 336
 337   // A function has a unique identifier, a checksum (we leave as zero) and a
 338   // set of blocks and a map of edges between blocks. This is the only GCOV
 339   // object users can construct, the blocks and lines will be rooted here.
 340   class GCOVFunction : public GCOVRecord {
 341    public:
 342      GCOVFunction(const DISubprogram *SP, Function *F, raw_ostream *os,
 343                   uint32_t Ident, bool UseCfgChecksum, bool ExitBlockBeforeBody)
 344          : SP(SP), Ident(Ident), UseCfgChecksum(UseCfgChecksum), CfgChecksum(0),
 345            ReturnBlock(1, os) {
 346       this->os = os;
 347
 348       LLVM_DEBUG(dbgs() << "Function: " << getFunctionName(SP) << "\n");
 349
 350       uint32_t i = 0;
 351       for (auto &BB : *F) {
 352         // Skip index 1 if it's assigned to the ReturnBlock.
 353         if (i == 1 && ExitBlockBeforeBody)
 354           ++i;
 355         Blocks.insert(std::make_pair(&BB, GCOVBlock(i++, os)));
 356       }
 357       if (!ExitBlockBeforeBody)
 358         ReturnBlock.Number = i;
 359
 360       std::string FunctionNameAndLine;
 361       raw_string_ostream FNLOS(FunctionNameAndLine);
 362       FNLOS << getFunctionName(SP) << SP->getLine();
 363       FNLOS.flush();
 364       FuncChecksum = hash_value(FunctionNameAndLine);
 365     }
 366
 367     GCOVBlock &getBlock(BasicBlock *BB) {
 368       return Blocks.find(BB)->second;
 369     }
 370
 371     GCOVBlock &getReturnBlock() {
 372       return ReturnBlock;
 373     }
 374
 375     std::string getEdgeDestinations() {
 376       std::string EdgeDestinations;
 377       raw_string_ostream EDOS(EdgeDestinations);
 378       Function *F = Blocks.begin()->first->getParent();
 379       for (BasicBlock &I : *F) {
 380         GCOVBlock &Block = getBlock(&I);
 381         for (int i = 0, e = Block.OutEdges.size(); i != e; ++i)
 382           EDOS << Block.OutEdges[i]->Number;
 383       }
 384       return EdgeDestinations;
 385     }
 386
 387     uint32_t getFuncChecksum() {
 388       return FuncChecksum;
 389     }
 390
 391     void setCfgChecksum(uint32_t Checksum) {
 392       CfgChecksum = Checksum;
 393     }
 394
 395     void writeOut() {
 396       writeBytes(FunctionTag, 4);
 397       SmallString<128> Filename = getFilename(SP);
 398       uint32_t BlockLen = 1 + 1 + 1 + lengthOfGCOVString(getFunctionName(SP)) +
 399                           1 + lengthOfGCOVString(Filename) + 1;
 400       if (UseCfgChecksum)
 401         ++BlockLen;
 402       write(BlockLen);
 403       write(Ident);
 404       write(FuncChecksum);
 405       if (UseCfgChecksum)
 406         write(CfgChecksum);
 407       writeGCOVString(getFunctionName(SP));
 408       writeGCOVString(Filename);
 409       write(SP->getLine());
 410
 411       // Emit count of blocks.
 412       writeBytes(BlockTag, 4);
 413       write(Blocks.size() + 1);
 414       for (int i = 0, e = Blocks.size() + 1; i != e; ++i) {
 415         write(0);  // No flags on our blocks.
 416       }
 417       LLVM_DEBUG(dbgs() << Blocks.size() << " blocks.\n");
 418
 419       // Emit edges between blocks.
 420       if (Blocks.empty()) return;
 421       Function *F = Blocks.begin()->first->getParent();
 422       for (BasicBlock &I : *F) {
 423         GCOVBlock &Block = getBlock(&I);
 424         if (Block.OutEdges.empty()) continue;
 425
 426         writeBytes(EdgeTag, 4);
 427         write(Block.OutEdges.size() * 2 + 1);
 428         write(Block.Number);
 429         for (int i = 0, e = Block.OutEdges.size(); i != e; ++i) {
 430           LLVM_DEBUG(dbgs() << Block.Number << " -> "
 431                             << Block.OutEdges[i]->Number << "\n");
 432           write(Block.OutEdges[i]->Number);
 433           write(0);  // no flags
 434         }
 435       }
 436
 437       // Emit lines for each block.
 438       for (BasicBlock &I : *F)
 439         getBlock(&I).writeOut();
 440     }
 441
 442    private:
 443      const DISubprogram *SP;
 444     uint32_t Ident;
 445     uint32_t FuncChecksum;
 446     bool UseCfgChecksum;
 447     uint32_t CfgChecksum;
 448     DenseMap<BasicBlock *, GCOVBlock> Blocks;
 449     GCOVBlock ReturnBlock;
 450   };
 451 }
 452
 453 // RegexesStr is a string containing differents regex separated by a semi-colon.
 454 // For example "foo\..*$;bar\..*$".
 455 std::vector<Regex> GCOVProfiler::createRegexesFromString(StringRef RegexesStr) {
 456   std::vector<Regex> Regexes;
 457   while (!RegexesStr.empty()) {
 458     std::pair<StringRef, StringRef> HeadTail = RegexesStr.split(';');
 459     if (!HeadTail.first.empty()) {
 460       Regex Re(HeadTail.first);
 461       std::string Err;
 462       if (!Re.isValid(Err)) {
 463         Ctx->emitError(Twine("Regex ") + HeadTail.first +
 464                        " is not valid: " + Err);
 465       }
 466       Regexes.emplace_back(std::move(Re));
 467     }
 468     RegexesStr = HeadTail.second;
 469   }
 470   return Regexes;
 471 }
 472
 473 bool GCOVProfiler::doesFilenameMatchARegex(StringRef Filename,
 474                                            std::vector<Regex> &Regexes) {
 475   for (Regex &Re : Regexes) {
 476     if (Re.match(Filename)) {
 477       return true;
 478     }
 479   }
 480   return false;
 481 }
 482
 483 bool GCOVProfiler::isFunctionInstrumented(const Function &F) {
 484   if (FilterRe.empty() && ExcludeRe.empty()) {
 485     return true;
 486   }
 487   SmallString<128> Filename = getFilename(F.getSubprogram());
 488   auto It = InstrumentedFiles.find(Filename);
 489   if (It != InstrumentedFiles.end()) {
 490     return It->second;
 491   }
 492
 493   SmallString<256> RealPath;
 494   StringRef RealFilename;
 495
 496   // Path can be
 497   // /usr/lib/gcc/x86_64-linux-gnu/8/../../../../include/c++/8/bits/*.h so for
 498   // such a case we must get the real_path.
 499   if (sys::fs::real_path(Filename, RealPath)) {
 500     // real_path can fail with path like "foo.c".
 501     RealFilename = Filename;
 502   } else {
 503     RealFilename = RealPath;
 504   }
 505
 506   bool ShouldInstrument;
 507   if (FilterRe.empty()) {
 508     ShouldInstrument = !doesFilenameMatchARegex(RealFilename, ExcludeRe);
 509   } else if (ExcludeRe.empty()) {
 510     ShouldInstrument = doesFilenameMatchARegex(RealFilename, FilterRe);
 511   } else {
 512     ShouldInstrument = doesFilenameMatchARegex(RealFilename, FilterRe) &&
 513                        !doesFilenameMatchARegex(RealFilename, ExcludeRe);
 514   }
 515   InstrumentedFiles[Filename] = ShouldInstrument;
 516   return ShouldInstrument;
 517 }
 518
 519 std::string GCOVProfiler::mangleName(const DICompileUnit *CU,
 520                                      GCovFileType OutputType) {
 521   bool Notes = OutputType == GCovFileType::GCNO;
 522
 523   if (NamedMDNode *GCov = M->getNamedMetadata("llvm.gcov")) {
 524     for (int i = 0, e = GCov->getNumOperands(); i != e; ++i) {
 525       MDNode *N = GCov->getOperand(i);
 526       bool ThreeElement = N->getNumOperands() == 3;
 527       if (!ThreeElement && N->getNumOperands() != 2)
 528         continue;
 529       if (dyn_cast<MDNode>(N->getOperand(ThreeElement ? 2 : 1)) != CU)
 530         continue;
 531
 532       if (ThreeElement) {
 533         // These nodes have no mangling to apply, it's stored mangled in the
 534         // bitcode.
 535         MDString *NotesFile = dyn_cast<MDString>(N->getOperand(0));
 536         MDString *DataFile = dyn_cast<MDString>(N->getOperand(1));
 537         if (!NotesFile || !DataFile)
 538           continue;
 539         return Notes ? NotesFile->getString() : DataFile->getString();
 540       }
 541
 542       MDString *GCovFile = dyn_cast<MDString>(N->getOperand(0));
 543       if (!GCovFile)
 544         continue;
 545
 546       SmallString<128> Filename = GCovFile->getString();
 547       sys::path::replace_extension(Filename, Notes ? "gcno" : "gcda");
 548       return Filename.str();
 549     }
 550   }
 551
 552   SmallString<128> Filename = CU->getFilename();
 553   sys::path::replace_extension(Filename, Notes ? "gcno" : "gcda");
 554   StringRef FName = sys::path::filename(Filename);
 555   SmallString<128> CurPath;
 556   if (sys::fs::current_path(CurPath)) return FName;
 557   sys::path::append(CurPath, FName);
 558   return CurPath.str();
 559 }
 560
 561 bool GCOVProfiler::runOnModule(
 562     Module &M, std::function<const TargetLibraryInfo &(Function &F)> GetTLI) {
 563   this->M = &M;
 564   this->GetTLI = std::move(GetTLI);
 565   Ctx = &M.getContext();
 566
 567   AddFlushBeforeForkAndExec();
 568
 569   FilterRe = createRegexesFromString(Options.Filter);
 570   ExcludeRe = createRegexesFromString(Options.Exclude);
 571
 572   if (Options.EmitNotes) emitProfileNotes();
 573   if (Options.EmitData) return emitProfileArcs();
 574   return false;
 575 }
 576
 577 PreservedAnalyses GCOVProfilerPass::run(Module &M,
 578                                         ModuleAnalysisManager &AM) {
 579
 580   GCOVProfiler Profiler(GCOVOpts);
 581   FunctionAnalysisManager &FAM =
 582       AM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager();
 583
 584   if (!Profiler.runOnModule(M, [&](Function &F) -> TargetLibraryInfo & {
 585         return FAM.getResult<TargetLibraryAnalysis>(F);
 586       }))
 587     return PreservedAnalyses::all();
 588
 589   return PreservedAnalyses::none();
 590 }
 591
 592 static bool functionHasLines(Function &F) {
 593   // Check whether this function actually has any source lines. Not only
 594   // do these waste space, they also can crash gcov.
 595   for (auto &BB : F) {
 596     for (auto &I : BB) {
 597       // Debug intrinsic locations correspond to the location of the
 598       // declaration, not necessarily any statements or expressions.
 599       if (isa<DbgInfoIntrinsic>(&I)) continue;
 600
 601       const DebugLoc &Loc = I.getDebugLoc();
 602       if (!Loc)
 603         continue;
 604
 605       // Artificial lines such as calls to the global constructors.
 606       if (Loc.getLine() == 0) continue;
 607
 608       return true;
 609     }
 610   }
 611   return false;
 612 }
 613
 614 static bool isUsingScopeBasedEH(Function &F) {
 615   if (!F.hasPersonalityFn()) return false;
 616
 617   EHPersonality Personality = classifyEHPersonality(F.getPersonalityFn());
 618   return isScopedEHPersonality(Personality);
 619 }
 620
 621 static bool shouldKeepInEntry(BasicBlock::iterator It) {
 622         if (isa<AllocaInst>(*It)) return true;
 623         if (isa<DbgInfoIntrinsic>(*It)) return true;
 624         if (auto *II = dyn_cast<IntrinsicInst>(It)) {
 625                 if (II->getIntrinsicID() == llvm::Intrinsic::localescape) return true;
 626         }
 627
 628         return false;
 629 }
 630
 631 void GCOVProfiler::AddFlushBeforeForkAndExec() {
 632   SmallVector<Instruction *, 2> ForkAndExecs;
 633   for (auto &F : M->functions()) {
 634     auto *TLI = &GetTLI(F);
 635     for (auto &I : instructions(F)) {
 636       if (CallInst *CI = dyn_cast<CallInst>(&I)) {
 637         if (Function *Callee = CI->getCalledFunction()) {
 638           LibFunc LF;
 639           if (TLI->getLibFunc(*Callee, LF) &&
 640               (LF == LibFunc_fork || LF == LibFunc_execl ||
 641                LF == LibFunc_execle || LF == LibFunc_execlp ||
 642                LF == LibFunc_execv || LF == LibFunc_execvp ||
 643                LF == LibFunc_execve || LF == LibFunc_execvpe ||
 644                LF == LibFunc_execvP)) {
 645             ForkAndExecs.push_back(&I);
 646           }
 647         }
 648       }
 649     }
 650   }
 651
 652   // We need to split the block after the fork/exec call
 653   // because else the counters for the lines after will be
 654   // the same as before the call.
 655   for (auto I : ForkAndExecs) {
 656     IRBuilder<> Builder(I);
 657     FunctionType *FTy = FunctionType::get(Builder.getVoidTy(), {}, false);
 658     FunctionCallee GCOVFlush = M->getOrInsertFunction("__gcov_flush", FTy);
 659     Builder.CreateCall(GCOVFlush);
 660     I->getParent()->splitBasicBlock(I);
 661   }
 662 }
 663
 664 void GCOVProfiler::emitProfileNotes() {
 665   NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
 666   if (!CU_Nodes) return;
 667
 668   for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
 669     // Each compile unit gets its own .gcno file. This means that whether we run
 670     // this pass over the original .o's as they're produced, or run it after
 671     // LTO, we'll generate the same .gcno files.
 672
 673     auto *CU = cast<DICompileUnit>(CU_Nodes->getOperand(i));
 674
 675     // Skip module skeleton (and module) CUs.
 676     if (CU->getDWOId())
 677       continue;
 678
 679     std::error_code EC;
 680     raw_fd_ostream out(mangleName(CU, GCovFileType::GCNO), EC,
 681                        sys::fs::OF_None);
 682     if (EC) {
 683       Ctx->emitError(Twine("failed to open coverage notes file for writing: ") +
 684                      EC.message());
 685       continue;
 686     }
 687
 688     std::string EdgeDestinations;
 689
 690     unsigned FunctionIdent = 0;
 691     for (auto &F : M->functions()) {
 692       DISubprogram *SP = F.getSubprogram();
 693       if (!SP) continue;
 694       if (!functionHasLines(F) || !isFunctionInstrumented(F))
 695         continue;
 696       // TODO: Functions using scope-based EH are currently not supported.
 697       if (isUsingScopeBasedEH(F)) continue;
 698
 699       // gcov expects every function to start with an entry block that has a
 700       // single successor, so split the entry block to make sure of that.
 701       BasicBlock &EntryBlock = F.getEntryBlock();
 702       BasicBlock::iterator It = EntryBlock.begin();
 703       while (shouldKeepInEntry(It))
 704         ++It;
 705       EntryBlock.splitBasicBlock(It);
 706
 707       Funcs.push_back(std::make_unique<GCOVFunction>(SP, &F, &out, FunctionIdent++,
 708                                                 Options.UseCfgChecksum,
 709                                                 Options.ExitBlockBeforeBody));
 710       GCOVFunction &Func = *Funcs.back();
 711
 712       // Add the function line number to the lines of the entry block
 713       // to have a counter for the function definition.
 714       uint32_t Line = SP->getLine();
 715       auto Filename = getFilename(SP);
 716       Func.getBlock(&EntryBlock).getFile(Filename).addLine(Line);
 717
 718       for (auto &BB : F) {
 719         GCOVBlock &Block = Func.getBlock(&BB);
 720         Instruction *TI = BB.getTerminator();
 721         if (int successors = TI->getNumSuccessors()) {
 722           for (int i = 0; i != successors; ++i) {
 723             Block.addEdge(Func.getBlock(TI->getSuccessor(i)));
 724           }
 725         } else if (isa<ReturnInst>(TI)) {
 726           Block.addEdge(Func.getReturnBlock());
 727         }
 728
 729         for (auto &I : BB) {
 730           // Debug intrinsic locations correspond to the location of the
 731           // declaration, not necessarily any statements or expressions.
 732           if (isa<DbgInfoIntrinsic>(&I)) continue;
 733
 734           const DebugLoc &Loc = I.getDebugLoc();
 735           if (!Loc)
 736             continue;
 737
 738           // Artificial lines such as calls to the global constructors.
 739           if (Loc.getLine() == 0 || Loc.isImplicitCode())
 740             continue;
 741
 742           if (Line == Loc.getLine()) continue;
 743           Line = Loc.getLine();
 744           if (SP != getDISubprogram(Loc.getScope()))
 745             continue;
 746
 747           GCOVLines &Lines = Block.getFile(Filename);
 748           Lines.addLine(Loc.getLine());
 749         }
 750         Line = 0;
 751       }
 752       EdgeDestinations += Func.getEdgeDestinations();
 753     }
 754
 755     FileChecksums.push_back(hash_value(EdgeDestinations));
 756     out.write("oncg", 4);
 757     out.write(ReversedVersion, 4);
 758     out.write(reinterpret_cast<char*>(&FileChecksums.back()), 4);
 759
 760     for (auto &Func : Funcs) {
 761       Func->setCfgChecksum(FileChecksums.back());
 762       Func->writeOut();
 763     }
 764
 765     out.write("\0\0\0\0\0\0\0\0", 8);  // EOF
 766     out.close();
 767   }
 768 }
 769
 770 bool GCOVProfiler::emitProfileArcs() {
 771   NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
 772   if (!CU_Nodes) return false;
 773
 774   bool Result = false;
 775   for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
 776     SmallVector<std::pair<GlobalVariable *, MDNode *>, 8> CountersBySP;
 777     for (auto &F : M->functions()) {
 778       DISubprogram *SP = F.getSubprogram();
 779       if (!SP) continue;
 780       if (!functionHasLines(F) || !isFunctionInstrumented(F))
 781         continue;
 782       // TODO: Functions using scope-based EH are currently not supported.
 783       if (isUsingScopeBasedEH(F)) continue;
 784       if (!Result) Result = true;
 785
 786       DenseMap<std::pair<BasicBlock *, BasicBlock *>, unsigned> EdgeToCounter;
 787       unsigned Edges = 0;
 788       for (auto &BB : F) {
 789         Instruction *TI = BB.getTerminator();
 790         if (isa<ReturnInst>(TI)) {
 791           EdgeToCounter[{&BB, nullptr}] = Edges++;
 792         } else {
 793           for (BasicBlock *Succ : successors(TI)) {
 794             EdgeToCounter[{&BB, Succ}] = Edges++;
 795           }
 796         }
 797       }
 798
 799       ArrayType *CounterTy =
 800         ArrayType::get(Type::getInt64Ty(*Ctx), Edges);
 801       GlobalVariable *Counters =
 802         new GlobalVariable(*M, CounterTy, false,
 803                            GlobalValue::InternalLinkage,
 804                            Constant::getNullValue(CounterTy),
 805                            "__llvm_gcov_ctr");
 806       CountersBySP.push_back(std::make_pair(Counters, SP));
 807
 808       // If a BB has several predecessors, use a PHINode to select
 809       // the correct counter.
 810       for (auto &BB : F) {
 811         const unsigned EdgeCount =
 812             std::distance(pred_begin(&BB), pred_end(&BB));
 813         if (EdgeCount) {
 814           // The phi node must be at the begin of the BB.
 815           IRBuilder<> BuilderForPhi(&*BB.begin());
 816           Type *Int64PtrTy = Type::getInt64PtrTy(*Ctx);
 817           PHINode *Phi = BuilderForPhi.CreatePHI(Int64PtrTy, EdgeCount);
 818           for (BasicBlock *Pred : predecessors(&BB)) {
 819             auto It = EdgeToCounter.find({Pred, &BB});
 820             assert(It != EdgeToCounter.end());
 821             const unsigned Edge = It->second;
 822             Value *EdgeCounter = BuilderForPhi.CreateConstInBoundsGEP2_64(
 823                 Counters->getValueType(), Counters, 0, Edge);
 824             Phi->addIncoming(EdgeCounter, Pred);
 825           }
 826
 827           // Skip phis, landingpads.
 828           IRBuilder<> Builder(&*BB.getFirstInsertionPt());
 829           Value *Count = Builder.CreateLoad(Builder.getInt64Ty(), Phi);
 830           Count = Builder.CreateAdd(Count, Builder.getInt64(1));
 831           Builder.CreateStore(Count, Phi);
 832
 833           Instruction *TI = BB.getTerminator();
 834           if (isa<ReturnInst>(TI)) {
 835             auto It = EdgeToCounter.find({&BB, nullptr});
 836             assert(It != EdgeToCounter.end());
 837             const unsigned Edge = It->second;
 838             Value *Counter = Builder.CreateConstInBoundsGEP2_64(
 839                 Counters->getValueType(), Counters, 0, Edge);
 840             Value *Count = Builder.CreateLoad(Builder.getInt64Ty(), Counter);
 841             Count = Builder.CreateAdd(Count, Builder.getInt64(1));
 842             Builder.CreateStore(Count, Counter);
 843           }
 844         }
 845       }
 846     }
 847
 848     Function *WriteoutF = insertCounterWriteout(CountersBySP);
 849     Function *FlushF = insertFlush(CountersBySP);
 850
 851     // Create a small bit of code that registers the "__llvm_gcov_writeout" to
 852     // be executed at exit and the "__llvm_gcov_flush" function to be executed
 853     // when "__gcov_flush" is called.
 854     FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
 855     Function *F = Function::Create(FTy, GlobalValue::InternalLinkage,
 856                                    "__llvm_gcov_init", M);
 857     F->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
 858     F->setLinkage(GlobalValue::InternalLinkage);
 859     F->addFnAttr(Attribute::NoInline);
 860     if (Options.NoRedZone)
 861       F->addFnAttr(Attribute::NoRedZone);
 862
 863     BasicBlock *BB = BasicBlock::Create(*Ctx, "entry", F);
 864     IRBuilder<> Builder(BB);
 865
 866     FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
 867     Type *Params[] = {
 868       PointerType::get(FTy, 0),
 869       PointerType::get(FTy, 0)
 870     };
 871     FTy = FunctionType::get(Builder.getVoidTy(), Params, false);
 872
 873     // Initialize the environment and register the local writeout and flush
 874     // functions.
 875     FunctionCallee GCOVInit = M->getOrInsertFunction("llvm_gcov_init", FTy);
 876     Builder.CreateCall(GCOVInit, {WriteoutF, FlushF});
 877     Builder.CreateRetVoid();
 878
 879     appendToGlobalCtors(*M, F, 0);
 880   }
 881
 882   return Result;
 883 }
 884
 885 FunctionCallee GCOVProfiler::getStartFileFunc(const TargetLibraryInfo *TLI) {
 886   Type *Args[] = {
 887     Type::getInt8PtrTy(*Ctx),  // const char *orig_filename
 888     Type::getInt8PtrTy(*Ctx),  // const char version[4]
 889     Type::getInt32Ty(*Ctx),    // uint32_t checksum
 890   };
 891   FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false);
 892   AttributeList AL;
 893   if (auto AK = TLI->getExtAttrForI32Param(false))
 894     AL = AL.addParamAttribute(*Ctx, 2, AK);
 895   FunctionCallee Res = M->getOrInsertFunction("llvm_gcda_start_file", FTy, AL);
 896   return Res;
 897 }
 898
 899 FunctionCallee GCOVProfiler::getEmitFunctionFunc(const TargetLibraryInfo *TLI) {
 900   Type *Args[] = {
 901     Type::getInt32Ty(*Ctx),    // uint32_t ident
 902     Type::getInt8PtrTy(*Ctx),  // const char *function_name
 903     Type::getInt32Ty(*Ctx),    // uint32_t func_checksum
 904     Type::getInt8Ty(*Ctx),     // uint8_t use_extra_checksum
 905     Type::getInt32Ty(*Ctx),    // uint32_t cfg_checksum
 906   };
 907   FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false);
 908   AttributeList AL;
 909   if (auto AK = TLI->getExtAttrForI32Param(false)) {
 910     AL = AL.addParamAttribute(*Ctx, 0, AK);
 911     AL = AL.addParamAttribute(*Ctx, 2, AK);
 912     AL = AL.addParamAttribute(*Ctx, 3, AK);
 913     AL = AL.addParamAttribute(*Ctx, 4, AK);
 914   }
 915   return M->getOrInsertFunction("llvm_gcda_emit_function", FTy);
 916 }
 917
 918 FunctionCallee GCOVProfiler::getEmitArcsFunc(const TargetLibraryInfo *TLI) {
 919   Type *Args[] = {
 920     Type::getInt32Ty(*Ctx),     // uint32_t num_counters
 921     Type::getInt64PtrTy(*Ctx),  // uint64_t *counters
 922   };
 923   FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false);
 924   AttributeList AL;
 925   if (auto AK = TLI->getExtAttrForI32Param(false))
 926     AL = AL.addParamAttribute(*Ctx, 0, AK);
 927   return M->getOrInsertFunction("llvm_gcda_emit_arcs", FTy, AL);
 928 }
 929
 930 FunctionCallee GCOVProfiler::getSummaryInfoFunc() {
 931   FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
 932   return M->getOrInsertFunction("llvm_gcda_summary_info", FTy);
 933 }
 934
 935 FunctionCallee GCOVProfiler::getEndFileFunc() {
 936   FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
 937   return M->getOrInsertFunction("llvm_gcda_end_file", FTy);
 938 }
 939
 940 Function *GCOVProfiler::insertCounterWriteout(
 941     ArrayRef<std::pair<GlobalVariable *, MDNode *> > CountersBySP) {
 942   FunctionType *WriteoutFTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
 943   Function *WriteoutF = M->getFunction("__llvm_gcov_writeout");
 944   if (!WriteoutF)
 945     WriteoutF = Function::Create(WriteoutFTy, GlobalValue::InternalLinkage,
 946                                  "__llvm_gcov_writeout", M);
 947   WriteoutF->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
 948   WriteoutF->addFnAttr(Attribute::NoInline);
 949   if (Options.NoRedZone)
 950     WriteoutF->addFnAttr(Attribute::NoRedZone);
 951
 952   BasicBlock *BB = BasicBlock::Create(*Ctx, "entry", WriteoutF);
 953   IRBuilder<> Builder(BB);
 954
 955   auto *TLI = &GetTLI(*WriteoutF);
 956
 957   FunctionCallee StartFile = getStartFileFunc(TLI);
 958   FunctionCallee EmitFunction = getEmitFunctionFunc(TLI);
 959   FunctionCallee EmitArcs = getEmitArcsFunc(TLI);
 960   FunctionCallee SummaryInfo = getSummaryInfoFunc();
 961   FunctionCallee EndFile = getEndFileFunc();
 962
 963   NamedMDNode *CUNodes = M->getNamedMetadata("llvm.dbg.cu");
 964   if (!CUNodes) {
 965     Builder.CreateRetVoid();
 966     return WriteoutF;
 967   }
 968
 969   // Collect the relevant data into a large constant data structure that we can
 970   // walk to write out everything.
 971   StructType *StartFileCallArgsTy = StructType::create(
 972       {Builder.getInt8PtrTy(), Builder.getInt8PtrTy(), Builder.getInt32Ty()});
 973   StructType *EmitFunctionCallArgsTy = StructType::create(
 974       {Builder.getInt32Ty(), Builder.getInt8PtrTy(), Builder.getInt32Ty(),
 975        Builder.getInt8Ty(), Builder.getInt32Ty()});
 976   StructType *EmitArcsCallArgsTy = StructType::create(
 977       {Builder.getInt32Ty(), Builder.getInt64Ty()->getPointerTo()});
 978   StructType *FileInfoTy =
 979       StructType::create({StartFileCallArgsTy, Builder.getInt32Ty(),
 980                           EmitFunctionCallArgsTy->getPointerTo(),
 981                           EmitArcsCallArgsTy->getPointerTo()});
 982
 983   Constant *Zero32 = Builder.getInt32(0);
 984   // Build an explicit array of two zeros for use in ConstantExpr GEP building.
 985   Constant *TwoZero32s[] = {Zero32, Zero32};
 986
 987   SmallVector<Constant *, 8> FileInfos;
 988   for (int i : llvm::seq<int>(0, CUNodes->getNumOperands())) {
 989     auto *CU = cast<DICompileUnit>(CUNodes->getOperand(i));
 990
 991     // Skip module skeleton (and module) CUs.
 992     if (CU->getDWOId())
 993       continue;
 994
 995     std::string FilenameGcda = mangleName(CU, GCovFileType::GCDA);
 996     uint32_t CfgChecksum = FileChecksums.empty() ? 0 : FileChecksums[i];
 997     auto *StartFileCallArgs = ConstantStruct::get(
 998         StartFileCallArgsTy, {Builder.CreateGlobalStringPtr(FilenameGcda),
 999                               Builder.CreateGlobalStringPtr(ReversedVersion),
1000                               Builder.getInt32(CfgChecksum)});
1001
1002     SmallVector<Constant *, 8> EmitFunctionCallArgsArray;
1003     SmallVector<Constant *, 8> EmitArcsCallArgsArray;
1004     for (int j : llvm::seq<int>(0, CountersBySP.size())) {
1005       auto *SP = cast_or_null<DISubprogram>(CountersBySP[j].second);
1006       uint32_t FuncChecksum = Funcs.empty() ? 0 : Funcs[j]->getFuncChecksum();
1007       EmitFunctionCallArgsArray.push_back(ConstantStruct::get(
1008           EmitFunctionCallArgsTy,
1009           {Builder.getInt32(j),
1010            Options.FunctionNamesInData
1011                ? Builder.CreateGlobalStringPtr(getFunctionName(SP))
1012                : Constant::getNullValue(Builder.getInt8PtrTy()),
1013            Builder.getInt32(FuncChecksum),
1014            Builder.getInt8(Options.UseCfgChecksum),
1015            Builder.getInt32(CfgChecksum)}));
1016
1017       GlobalVariable *GV = CountersBySP[j].first;
1018       unsigned Arcs = cast<ArrayType>(GV->getValueType())->getNumElements();
1019       EmitArcsCallArgsArray.push_back(ConstantStruct::get(
1020           EmitArcsCallArgsTy,
1021           {Builder.getInt32(Arcs), ConstantExpr::getInBoundsGetElementPtr(
1022                                        GV->getValueType(), GV, TwoZero32s)}));
1023     }
1024     // Create global arrays for the two emit calls.
1025     int CountersSize = CountersBySP.size();
1026     assert(CountersSize == (int)EmitFunctionCallArgsArray.size() &&
1027            "Mismatched array size!");
1028     assert(CountersSize == (int)EmitArcsCallArgsArray.size() &&
1029            "Mismatched array size!");
1030     auto *EmitFunctionCallArgsArrayTy =
1031         ArrayType::get(EmitFunctionCallArgsTy, CountersSize);
1032     auto *EmitFunctionCallArgsArrayGV = new GlobalVariable(
1033         *M, EmitFunctionCallArgsArrayTy, /*isConstant*/ true,
1034         GlobalValue::InternalLinkage,
1035         ConstantArray::get(EmitFunctionCallArgsArrayTy,
1036                            EmitFunctionCallArgsArray),
1037         Twine("__llvm_internal_gcov_emit_function_args.") + Twine(i));
1038     auto *EmitArcsCallArgsArrayTy =
1039         ArrayType::get(EmitArcsCallArgsTy, CountersSize);
1040     EmitFunctionCallArgsArrayGV->setUnnamedAddr(
1041         GlobalValue::UnnamedAddr::Global);
1042     auto *EmitArcsCallArgsArrayGV = new GlobalVariable(
1043         *M, EmitArcsCallArgsArrayTy, /*isConstant*/ true,
1044         GlobalValue::InternalLinkage,
1045         ConstantArray::get(EmitArcsCallArgsArrayTy, EmitArcsCallArgsArray),
1046         Twine("__llvm_internal_gcov_emit_arcs_args.") + Twine(i));
1047     EmitArcsCallArgsArrayGV->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
1048
1049     FileInfos.push_back(ConstantStruct::get(
1050         FileInfoTy,
1051         {StartFileCallArgs, Builder.getInt32(CountersSize),
1052          ConstantExpr::getInBoundsGetElementPtr(EmitFunctionCallArgsArrayTy,
1053                                                 EmitFunctionCallArgsArrayGV,
1054                                                 TwoZero32s),
1055          ConstantExpr::getInBoundsGetElementPtr(
1056              EmitArcsCallArgsArrayTy, EmitArcsCallArgsArrayGV, TwoZero32s)}));
1057   }
1058
1059   // If we didn't find anything to actually emit, bail on out.
1060   if (FileInfos.empty()) {
1061     Builder.CreateRetVoid();
1062     return WriteoutF;
1063   }
1064
1065   // To simplify code, we cap the number of file infos we write out to fit
1066   // easily in a 32-bit signed integer. This gives consistent behavior between
1067   // 32-bit and 64-bit systems without requiring (potentially very slow) 64-bit
1068   // operations on 32-bit systems. It also seems unreasonable to try to handle
1069   // more than 2 billion files.
1070   if ((int64_t)FileInfos.size() > (int64_t)INT_MAX)
1071     FileInfos.resize(INT_MAX);
1072
1073   // Create a global for the entire data structure so we can walk it more
1074   // easily.
1075   auto *FileInfoArrayTy = ArrayType::get(FileInfoTy, FileInfos.size());
1076   auto *FileInfoArrayGV = new GlobalVariable(
1077       *M, FileInfoArrayTy, /*isConstant*/ true, GlobalValue::InternalLinkage,
1078       ConstantArray::get(FileInfoArrayTy, FileInfos),
1079       "__llvm_internal_gcov_emit_file_info");
1080   FileInfoArrayGV->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
1081
1082   // Create the CFG for walking this data structure.
1083   auto *FileLoopHeader =
1084       BasicBlock::Create(*Ctx, "file.loop.header", WriteoutF);
1085   auto *CounterLoopHeader =
1086       BasicBlock::Create(*Ctx, "counter.loop.header", WriteoutF);
1087   auto *FileLoopLatch = BasicBlock::Create(*Ctx, "file.loop.latch", WriteoutF);
1088   auto *ExitBB = BasicBlock::Create(*Ctx, "exit", WriteoutF);
1089
1090   // We always have at least one file, so just branch to the header.
1091   Builder.CreateBr(FileLoopHeader);
1092
1093   // The index into the files structure is our loop induction variable.
1094   Builder.SetInsertPoint(FileLoopHeader);
1095   PHINode *IV =
1096       Builder.CreatePHI(Builder.getInt32Ty(), /*NumReservedValues*/ 2);
1097   IV->addIncoming(Builder.getInt32(0), BB);
1098   auto *FileInfoPtr = Builder.CreateInBoundsGEP(
1099       FileInfoArrayTy, FileInfoArrayGV, {Builder.getInt32(0), IV});
1100   auto *StartFileCallArgsPtr =
1101       Builder.CreateStructGEP(FileInfoTy, FileInfoPtr, 0);
1102   auto *StartFileCall = Builder.CreateCall(
1103       StartFile,
1104       {Builder.CreateLoad(StartFileCallArgsTy->getElementType(0),
1105                           Builder.CreateStructGEP(StartFileCallArgsTy,
1106                                                   StartFileCallArgsPtr, 0)),
1107        Builder.CreateLoad(StartFileCallArgsTy->getElementType(1),
1108                           Builder.CreateStructGEP(StartFileCallArgsTy,
1109                                                   StartFileCallArgsPtr, 1)),
1110        Builder.CreateLoad(StartFileCallArgsTy->getElementType(2),
1111                           Builder.CreateStructGEP(StartFileCallArgsTy,
1112                                                   StartFileCallArgsPtr, 2))});
1113   if (auto AK = TLI->getExtAttrForI32Param(false))
1114     StartFileCall->addParamAttr(2, AK);
1115   auto *NumCounters =
1116       Builder.CreateLoad(FileInfoTy->getElementType(1),
1117                          Builder.CreateStructGEP(FileInfoTy, FileInfoPtr, 1));
1118   auto *EmitFunctionCallArgsArray =
1119       Builder.CreateLoad(FileInfoTy->getElementType(2),
1120                          Builder.CreateStructGEP(FileInfoTy, FileInfoPtr, 2));
1121   auto *EmitArcsCallArgsArray =
1122       Builder.CreateLoad(FileInfoTy->getElementType(3),
1123                          Builder.CreateStructGEP(FileInfoTy, FileInfoPtr, 3));
1124   auto *EnterCounterLoopCond =
1125       Builder.CreateICmpSLT(Builder.getInt32(0), NumCounters);
1126   Builder.CreateCondBr(EnterCounterLoopCond, CounterLoopHeader, FileLoopLatch);
1127
1128   Builder.SetInsertPoint(CounterLoopHeader);
1129   auto *JV = Builder.CreatePHI(Builder.getInt32Ty(), /*NumReservedValues*/ 2);
1130   JV->addIncoming(Builder.getInt32(0), FileLoopHeader);
1131   auto *EmitFunctionCallArgsPtr = Builder.CreateInBoundsGEP(
1132       EmitFunctionCallArgsTy, EmitFunctionCallArgsArray, JV);
1133   auto *EmitFunctionCall = Builder.CreateCall(
1134       EmitFunction,
1135       {Builder.CreateLoad(EmitFunctionCallArgsTy->getElementType(0),
1136                           Builder.CreateStructGEP(EmitFunctionCallArgsTy,
1137                                                   EmitFunctionCallArgsPtr, 0)),
1138        Builder.CreateLoad(EmitFunctionCallArgsTy->getElementType(1),
1139                           Builder.CreateStructGEP(EmitFunctionCallArgsTy,
1140                                                   EmitFunctionCallArgsPtr, 1)),
1141        Builder.CreateLoad(EmitFunctionCallArgsTy->getElementType(2),
1142                           Builder.CreateStructGEP(EmitFunctionCallArgsTy,
1143                                                   EmitFunctionCallArgsPtr, 2)),
1144        Builder.CreateLoad(EmitFunctionCallArgsTy->getElementType(3),
1145                           Builder.CreateStructGEP(EmitFunctionCallArgsTy,
1146                                                   EmitFunctionCallArgsPtr, 3)),
1147        Builder.CreateLoad(EmitFunctionCallArgsTy->getElementType(4),
1148                           Builder.CreateStructGEP(EmitFunctionCallArgsTy,
1149                                                   EmitFunctionCallArgsPtr,
1150                                                   4))});
1151   if (auto AK = TLI->getExtAttrForI32Param(false)) {
1152     EmitFunctionCall->addParamAttr(0, AK);
1153     EmitFunctionCall->addParamAttr(2, AK);
1154     EmitFunctionCall->addParamAttr(3, AK);
1155     EmitFunctionCall->addParamAttr(4, AK);
1156   }
1157   auto *EmitArcsCallArgsPtr =
1158       Builder.CreateInBoundsGEP(EmitArcsCallArgsTy, EmitArcsCallArgsArray, JV);
1159   auto *EmitArcsCall = Builder.CreateCall(
1160       EmitArcs,
1161       {Builder.CreateLoad(
1162            EmitArcsCallArgsTy->getElementType(0),
1163            Builder.CreateStructGEP(EmitArcsCallArgsTy, EmitArcsCallArgsPtr, 0)),
1164        Builder.CreateLoad(EmitArcsCallArgsTy->getElementType(1),
1165                           Builder.CreateStructGEP(EmitArcsCallArgsTy,
1166                                                   EmitArcsCallArgsPtr, 1))});
1167   if (auto AK = TLI->getExtAttrForI32Param(false))
1168     EmitArcsCall->addParamAttr(0, AK);
1169   auto *NextJV = Builder.CreateAdd(JV, Builder.getInt32(1));
1170   auto *CounterLoopCond = Builder.CreateICmpSLT(NextJV, NumCounters);
1171   Builder.CreateCondBr(CounterLoopCond, CounterLoopHeader, FileLoopLatch);
1172   JV->addIncoming(NextJV, CounterLoopHeader);
1173
1174   Builder.SetInsertPoint(FileLoopLatch);
1175   Builder.CreateCall(SummaryInfo, {});
1176   Builder.CreateCall(EndFile, {});
1177   auto *NextIV = Builder.CreateAdd(IV, Builder.getInt32(1));
1178   auto *FileLoopCond =
1179       Builder.CreateICmpSLT(NextIV, Builder.getInt32(FileInfos.size()));
1180   Builder.CreateCondBr(FileLoopCond, FileLoopHeader, ExitBB);
1181   IV->addIncoming(NextIV, FileLoopLatch);
1182
1183   Builder.SetInsertPoint(ExitBB);
1184   Builder.CreateRetVoid();
1185
1186   return WriteoutF;
1187 }
1188
1189 Function *GCOVProfiler::
1190 insertFlush(ArrayRef<std::pair<GlobalVariable*, MDNode*> > CountersBySP) {
1191   FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
1192   Function *FlushF = M->getFunction("__llvm_gcov_flush");
1193   if (!FlushF)
1194     FlushF = Function::Create(FTy, GlobalValue::InternalLinkage,
1195                               "__llvm_gcov_flush", M);
1196   else
1197     FlushF->setLinkage(GlobalValue::InternalLinkage);
1198   FlushF->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
1199   FlushF->addFnAttr(Attribute::NoInline);
1200   if (Options.NoRedZone)
1201     FlushF->addFnAttr(Attribute::NoRedZone);
1202
1203   BasicBlock *Entry = BasicBlock::Create(*Ctx, "entry", FlushF);
1204
1205   // Write out the current counters.
1206   Function *WriteoutF = M->getFunction("__llvm_gcov_writeout");
1207   assert(WriteoutF && "Need to create the writeout function first!");
1208
1209   IRBuilder<> Builder(Entry);
1210   Builder.CreateCall(WriteoutF, {});
1211
1212   // Zero out the counters.
1213   for (const auto &I : CountersBySP) {
1214     GlobalVariable *GV = I.first;
1215     Constant *Null = Constant::getNullValue(GV->getValueType());
1216     Builder.CreateStore(Null, GV);
1217   }
1218
1219   Type *RetTy = FlushF->getReturnType();
1220   if (RetTy == Type::getVoidTy(*Ctx))
1221     Builder.CreateRetVoid();
1222   else if (RetTy->isIntegerTy())
1223     // Used if __llvm_gcov_flush was implicitly declared.
1224     Builder.CreateRet(ConstantInt::get(RetTy, 0));
1225   else
1226     report_fatal_error("invalid return type for __llvm_gcov_flush");
1227
1228   return FlushF;
1229 }