lib/ProfileData/GCOV.cpp

   1 //===- GCOV.cpp - LLVM coverage tool --------------------------------------===//
   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 // GCOV implements the interface to read and write coverage files that use
  10 // 'gcov' format.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/ProfileData/GCOV.h"
  15 #include "llvm/ADT/STLExtras.h"
  16 #include "llvm/Config/llvm-config.h"
  17 #include "llvm/Support/Debug.h"
  18 #include "llvm/Support/FileSystem.h"
  19 #include "llvm/Support/Format.h"
  20 #include "llvm/Support/Path.h"
  21 #include "llvm/Support/MD5.h"
  22 #include "llvm/Support/raw_ostream.h"
  23 #include <algorithm>
  24 #include <system_error>
  25
  26 using namespace llvm;
  27
  28 //===----------------------------------------------------------------------===//
  29 // GCOVFile implementation.
  30
  31 /// readGCNO - Read GCNO buffer.
  32 bool GCOVFile::readGCNO(GCOVBuffer &Buffer) {
  33   if (!Buffer.readGCNOFormat())
  34     return false;
  35   if (!Buffer.readGCOVVersion(Version))
  36     return false;
  37
  38   if (!Buffer.readInt(Checksum))
  39     return false;
  40   while (true) {
  41     if (!Buffer.readFunctionTag())
  42       break;
  43     auto GFun = std::make_unique<GCOVFunction>(*this);
  44     if (!GFun->readGCNO(Buffer, Version))
  45       return false;
  46     Functions.push_back(std::move(GFun));
  47   }
  48
  49   GCNOInitialized = true;
  50   return true;
  51 }
  52
  53 /// readGCDA - Read GCDA buffer. It is required that readGCDA() can only be
  54 /// called after readGCNO().
  55 bool GCOVFile::readGCDA(GCOVBuffer &Buffer) {
  56   assert(GCNOInitialized && "readGCDA() can only be called after readGCNO()");
  57   if (!Buffer.readGCDAFormat())
  58     return false;
  59   GCOV::GCOVVersion GCDAVersion;
  60   if (!Buffer.readGCOVVersion(GCDAVersion))
  61     return false;
  62   if (Version != GCDAVersion) {
  63     errs() << "GCOV versions do not match.\n";
  64     return false;
  65   }
  66
  67   uint32_t GCDAChecksum;
  68   if (!Buffer.readInt(GCDAChecksum))
  69     return false;
  70   if (Checksum != GCDAChecksum) {
  71     errs() << "File checksums do not match: " << Checksum
  72            << " != " << GCDAChecksum << ".\n";
  73     return false;
  74   }
  75   for (size_t i = 0, e = Functions.size(); i < e; ++i) {
  76     if (!Buffer.readFunctionTag()) {
  77       errs() << "Unexpected number of functions.\n";
  78       return false;
  79     }
  80     if (!Functions[i]->readGCDA(Buffer, Version))
  81       return false;
  82   }
  83   if (Buffer.readObjectTag()) {
  84     uint32_t Length;
  85     uint32_t Dummy;
  86     if (!Buffer.readInt(Length))
  87       return false;
  88     if (!Buffer.readInt(Dummy))
  89       return false; // checksum
  90     if (!Buffer.readInt(Dummy))
  91       return false; // num
  92     if (!Buffer.readInt(RunCount))
  93       return false;
  94     Buffer.advanceCursor(Length - 3);
  95   }
  96   while (Buffer.readProgramTag()) {
  97     uint32_t Length;
  98     if (!Buffer.readInt(Length))
  99       return false;
 100     Buffer.advanceCursor(Length);
 101     ++ProgramCount;
 102   }
 103
 104   return true;
 105 }
 106
 107 void GCOVFile::print(raw_ostream &OS) const {
 108   for (const auto &FPtr : Functions)
 109     FPtr->print(OS);
 110 }
 111
 112 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
 113 /// dump - Dump GCOVFile content to dbgs() for debugging purposes.
 114 LLVM_DUMP_METHOD void GCOVFile::dump() const { print(dbgs()); }
 115 #endif
 116
 117 /// collectLineCounts - Collect line counts. This must be used after
 118 /// reading .gcno and .gcda files.
 119 void GCOVFile::collectLineCounts(FileInfo &FI) {
 120   for (const auto &FPtr : Functions)
 121     FPtr->collectLineCounts(FI);
 122   FI.setRunCount(RunCount);
 123   FI.setProgramCount(ProgramCount);
 124 }
 125
 126 //===----------------------------------------------------------------------===//
 127 // GCOVFunction implementation.
 128
 129 /// readGCNO - Read a function from the GCNO buffer. Return false if an error
 130 /// occurs.
 131 bool GCOVFunction::readGCNO(GCOVBuffer &Buff, GCOV::GCOVVersion Version) {
 132   uint32_t Dummy;
 133   if (!Buff.readInt(Dummy))
 134     return false; // Function header length
 135   if (!Buff.readInt(Ident))
 136     return false;
 137   if (!Buff.readInt(Checksum))
 138     return false;
 139   if (Version != GCOV::V402) {
 140     uint32_t CfgChecksum;
 141     if (!Buff.readInt(CfgChecksum))
 142       return false;
 143     if (Parent.getChecksum() != CfgChecksum) {
 144       errs() << "File checksums do not match: " << Parent.getChecksum()
 145              << " != " << CfgChecksum << " in (" << Name << ").\n";
 146       return false;
 147     }
 148   }
 149   if (!Buff.readString(Name))
 150     return false;
 151   if (!Buff.readString(Filename))
 152     return false;
 153   if (!Buff.readInt(LineNumber))
 154     return false;
 155
 156   // read blocks.
 157   if (!Buff.readBlockTag()) {
 158     errs() << "Block tag not found.\n";
 159     return false;
 160   }
 161   uint32_t BlockCount;
 162   if (!Buff.readInt(BlockCount))
 163     return false;
 164   for (uint32_t i = 0, e = BlockCount; i != e; ++i) {
 165     if (!Buff.readInt(Dummy))
 166       return false; // Block flags;
 167     Blocks.push_back(std::make_unique<GCOVBlock>(*this, i));
 168   }
 169
 170   // read edges.
 171   while (Buff.readEdgeTag()) {
 172     uint32_t EdgeCount;
 173     if (!Buff.readInt(EdgeCount))
 174       return false;
 175     EdgeCount = (EdgeCount - 1) / 2;
 176     uint32_t BlockNo;
 177     if (!Buff.readInt(BlockNo))
 178       return false;
 179     if (BlockNo >= BlockCount) {
 180       errs() << "Unexpected block number: " << BlockNo << " (in " << Name
 181              << ").\n";
 182       return false;
 183     }
 184     for (uint32_t i = 0, e = EdgeCount; i != e; ++i) {
 185       uint32_t Dst;
 186       if (!Buff.readInt(Dst))
 187         return false;
 188       Edges.push_back(std::make_unique<GCOVEdge>(*Blocks[BlockNo], *Blocks[Dst]));
 189       GCOVEdge *Edge = Edges.back().get();
 190       Blocks[BlockNo]->addDstEdge(Edge);
 191       Blocks[Dst]->addSrcEdge(Edge);
 192       if (!Buff.readInt(Dummy))
 193         return false; // Edge flag
 194     }
 195   }
 196
 197   // read line table.
 198   while (Buff.readLineTag()) {
 199     uint32_t LineTableLength;
 200     // Read the length of this line table.
 201     if (!Buff.readInt(LineTableLength))
 202       return false;
 203     uint32_t EndPos = Buff.getCursor() + LineTableLength * 4;
 204     uint32_t BlockNo;
 205     // Read the block number this table is associated with.
 206     if (!Buff.readInt(BlockNo))
 207       return false;
 208     if (BlockNo >= BlockCount) {
 209       errs() << "Unexpected block number: " << BlockNo << " (in " << Name
 210              << ").\n";
 211       return false;
 212     }
 213     GCOVBlock &Block = *Blocks[BlockNo];
 214     // Read the word that pads the beginning of the line table. This may be a
 215     // flag of some sort, but seems to always be zero.
 216     if (!Buff.readInt(Dummy))
 217       return false;
 218
 219     // Line information starts here and continues up until the last word.
 220     if (Buff.getCursor() != (EndPos - sizeof(uint32_t))) {
 221       StringRef F;
 222       // Read the source file name.
 223       if (!Buff.readString(F))
 224         return false;
 225       if (Filename != F) {
 226         errs() << "Multiple sources for a single basic block: " << Filename
 227                << " != " << F << " (in " << Name << ").\n";
 228         return false;
 229       }
 230       // Read lines up to, but not including, the null terminator.
 231       while (Buff.getCursor() < (EndPos - 2 * sizeof(uint32_t))) {
 232         uint32_t Line;
 233         if (!Buff.readInt(Line))
 234           return false;
 235         // Line 0 means this instruction was injected by the compiler. Skip it.
 236         if (!Line)
 237           continue;
 238         Block.addLine(Line);
 239       }
 240       // Read the null terminator.
 241       if (!Buff.readInt(Dummy))
 242         return false;
 243     }
 244     // The last word is either a flag or padding, it isn't clear which. Skip
 245     // over it.
 246     if (!Buff.readInt(Dummy))
 247       return false;
 248   }
 249   return true;
 250 }
 251
 252 /// readGCDA - Read a function from the GCDA buffer. Return false if an error
 253 /// occurs.
 254 bool GCOVFunction::readGCDA(GCOVBuffer &Buff, GCOV::GCOVVersion Version) {
 255   uint32_t HeaderLength;
 256   if (!Buff.readInt(HeaderLength))
 257     return false; // Function header length
 258
 259   uint64_t EndPos = Buff.getCursor() + HeaderLength * sizeof(uint32_t);
 260
 261   uint32_t GCDAIdent;
 262   if (!Buff.readInt(GCDAIdent))
 263     return false;
 264   if (Ident != GCDAIdent) {
 265     errs() << "Function identifiers do not match: " << Ident
 266            << " != " << GCDAIdent << " (in " << Name << ").\n";
 267     return false;
 268   }
 269
 270   uint32_t GCDAChecksum;
 271   if (!Buff.readInt(GCDAChecksum))
 272     return false;
 273   if (Checksum != GCDAChecksum) {
 274     errs() << "Function checksums do not match: " << Checksum
 275            << " != " << GCDAChecksum << " (in " << Name << ").\n";
 276     return false;
 277   }
 278
 279   uint32_t CfgChecksum;
 280   if (Version != GCOV::V402) {
 281     if (!Buff.readInt(CfgChecksum))
 282       return false;
 283     if (Parent.getChecksum() != CfgChecksum) {
 284       errs() << "File checksums do not match: " << Parent.getChecksum()
 285              << " != " << CfgChecksum << " (in " << Name << ").\n";
 286       return false;
 287     }
 288   }
 289
 290   if (Buff.getCursor() < EndPos) {
 291     StringRef GCDAName;
 292     if (!Buff.readString(GCDAName))
 293       return false;
 294     if (Name != GCDAName) {
 295       errs() << "Function names do not match: " << Name << " != " << GCDAName
 296              << ".\n";
 297       return false;
 298     }
 299   }
 300
 301   if (!Buff.readArcTag()) {
 302     errs() << "Arc tag not found (in " << Name << ").\n";
 303     return false;
 304   }
 305
 306   uint32_t Count;
 307   if (!Buff.readInt(Count))
 308     return false;
 309   Count /= 2;
 310
 311   // This for loop adds the counts for each block. A second nested loop is
 312   // required to combine the edge counts that are contained in the GCDA file.
 313   for (uint32_t BlockNo = 0; Count > 0; ++BlockNo) {
 314     // The last block is always reserved for exit block
 315     if (BlockNo >= Blocks.size()) {
 316       errs() << "Unexpected number of edges (in " << Name << ").\n";
 317       return false;
 318     }
 319     if (BlockNo == Blocks.size() - 1)
 320       errs() << "(" << Name << ") has arcs from exit block.\n";
 321     GCOVBlock &Block = *Blocks[BlockNo];
 322     for (size_t EdgeNo = 0, End = Block.getNumDstEdges(); EdgeNo < End;
 323          ++EdgeNo) {
 324       if (Count == 0) {
 325         errs() << "Unexpected number of edges (in " << Name << ").\n";
 326         return false;
 327       }
 328       uint64_t ArcCount;
 329       if (!Buff.readInt64(ArcCount))
 330         return false;
 331       Block.addCount(EdgeNo, ArcCount);
 332       --Count;
 333     }
 334     Block.sortDstEdges();
 335   }
 336   return true;
 337 }
 338
 339 /// getEntryCount - Get the number of times the function was called by
 340 /// retrieving the entry block's count.
 341 uint64_t GCOVFunction::getEntryCount() const {
 342   return Blocks.front()->getCount();
 343 }
 344
 345 /// getExitCount - Get the number of times the function returned by retrieving
 346 /// the exit block's count.
 347 uint64_t GCOVFunction::getExitCount() const {
 348   return Blocks.back()->getCount();
 349 }
 350
 351 void GCOVFunction::print(raw_ostream &OS) const {
 352   OS << "===== " << Name << " (" << Ident << ") @ " << Filename << ":"
 353      << LineNumber << "\n";
 354   for (const auto &Block : Blocks)
 355     Block->print(OS);
 356 }
 357
 358 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
 359 /// dump - Dump GCOVFunction content to dbgs() for debugging purposes.
 360 LLVM_DUMP_METHOD void GCOVFunction::dump() const { print(dbgs()); }
 361 #endif
 362
 363 /// collectLineCounts - Collect line counts. This must be used after
 364 /// reading .gcno and .gcda files.
 365 void GCOVFunction::collectLineCounts(FileInfo &FI) {
 366   // If the line number is zero, this is a function that doesn't actually appear
 367   // in the source file, so there isn't anything we can do with it.
 368   if (LineNumber == 0)
 369     return;
 370
 371   for (const auto &Block : Blocks)
 372     Block->collectLineCounts(FI);
 373   FI.addFunctionLine(Filename, LineNumber, this);
 374 }
 375
 376 //===----------------------------------------------------------------------===//
 377 // GCOVBlock implementation.
 378
 379 /// ~GCOVBlock - Delete GCOVBlock and its content.
 380 GCOVBlock::~GCOVBlock() {
 381   SrcEdges.clear();
 382   DstEdges.clear();
 383   Lines.clear();
 384 }
 385
 386 /// addCount - Add to block counter while storing the edge count. If the
 387 /// destination has no outgoing edges, also update that block's count too.
 388 void GCOVBlock::addCount(size_t DstEdgeNo, uint64_t N) {
 389   assert(DstEdgeNo < DstEdges.size()); // up to caller to ensure EdgeNo is valid
 390   DstEdges[DstEdgeNo]->Count = N;
 391   Counter += N;
 392   if (!DstEdges[DstEdgeNo]->Dst.getNumDstEdges())
 393     DstEdges[DstEdgeNo]->Dst.Counter += N;
 394 }
 395
 396 /// sortDstEdges - Sort destination edges by block number, nop if already
 397 /// sorted. This is required for printing branch info in the correct order.
 398 void GCOVBlock::sortDstEdges() {
 399   if (!DstEdgesAreSorted)
 400     llvm::stable_sort(DstEdges, [](const GCOVEdge *E1, const GCOVEdge *E2) {
 401       return E1->Dst.Number < E2->Dst.Number;
 402     });
 403 }
 404
 405 /// collectLineCounts - Collect line counts. This must be used after
 406 /// reading .gcno and .gcda files.
 407 void GCOVBlock::collectLineCounts(FileInfo &FI) {
 408   for (uint32_t N : Lines)
 409     FI.addBlockLine(Parent.getFilename(), N, this);
 410 }
 411
 412 void GCOVBlock::print(raw_ostream &OS) const {
 413   OS << "Block : " << Number << " Counter : " << Counter << "\n";
 414   if (!SrcEdges.empty()) {
 415     OS << "\tSource Edges : ";
 416     for (const GCOVEdge *Edge : SrcEdges)
 417       OS << Edge->Src.Number << " (" << Edge->Count << "), ";
 418     OS << "\n";
 419   }
 420   if (!DstEdges.empty()) {
 421     OS << "\tDestination Edges : ";
 422     for (const GCOVEdge *Edge : DstEdges)
 423       OS << Edge->Dst.Number << " (" << Edge->Count << "), ";
 424     OS << "\n";
 425   }
 426   if (!Lines.empty()) {
 427     OS << "\tLines : ";
 428     for (uint32_t N : Lines)
 429       OS << (N) << ",";
 430     OS << "\n";
 431   }
 432 }
 433
 434 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
 435 /// dump - Dump GCOVBlock content to dbgs() for debugging purposes.
 436 LLVM_DUMP_METHOD void GCOVBlock::dump() const { print(dbgs()); }
 437 #endif
 438
 439 //===----------------------------------------------------------------------===//
 440 // Cycles detection
 441 //
 442 // The algorithm in GCC is based on the algorihtm by Hawick & James:
 443 //   "Enumerating Circuits and Loops in Graphs with Self-Arcs and Multiple-Arcs"
 444 //   http://complexity.massey.ac.nz/cstn/013/cstn-013.pdf.
 445
 446 /// Get the count for the detected cycle.
 447 uint64_t GCOVBlock::getCycleCount(const Edges &Path) {
 448   uint64_t CycleCount = std::numeric_limits<uint64_t>::max();
 449   for (auto E : Path) {
 450     CycleCount = std::min(E->CyclesCount, CycleCount);
 451   }
 452   for (auto E : Path) {
 453     E->CyclesCount -= CycleCount;
 454   }
 455   return CycleCount;
 456 }
 457
 458 /// Unblock a vertex previously marked as blocked.
 459 void GCOVBlock::unblock(const GCOVBlock *U, BlockVector &Blocked,
 460                         BlockVectorLists &BlockLists) {
 461   auto it = find(Blocked, U);
 462   if (it == Blocked.end()) {
 463     return;
 464   }
 465
 466   const size_t index = it - Blocked.begin();
 467   Blocked.erase(it);
 468
 469   const BlockVector ToUnblock(BlockLists[index]);
 470   BlockLists.erase(BlockLists.begin() + index);
 471   for (auto GB : ToUnblock) {
 472     GCOVBlock::unblock(GB, Blocked, BlockLists);
 473   }
 474 }
 475
 476 bool GCOVBlock::lookForCircuit(const GCOVBlock *V, const GCOVBlock *Start,
 477                                Edges &Path, BlockVector &Blocked,
 478                                BlockVectorLists &BlockLists,
 479                                const BlockVector &Blocks, uint64_t &Count) {
 480   Blocked.push_back(V);
 481   BlockLists.emplace_back(BlockVector());
 482   bool FoundCircuit = false;
 483
 484   for (auto E : V->dsts()) {
 485     const GCOVBlock *W = &E->Dst;
 486     if (W < Start || find(Blocks, W) == Blocks.end()) {
 487       continue;
 488     }
 489
 490     Path.push_back(E);
 491
 492     if (W == Start) {
 493       // We've a cycle.
 494       Count += GCOVBlock::getCycleCount(Path);
 495       FoundCircuit = true;
 496     } else if (find(Blocked, W) == Blocked.end() && // W is not blocked.
 497                GCOVBlock::lookForCircuit(W, Start, Path, Blocked, BlockLists,
 498                                          Blocks, Count)) {
 499       FoundCircuit = true;
 500     }
 501
 502     Path.pop_back();
 503   }
 504
 505   if (FoundCircuit) {
 506     GCOVBlock::unblock(V, Blocked, BlockLists);
 507   } else {
 508     for (auto E : V->dsts()) {
 509       const GCOVBlock *W = &E->Dst;
 510       if (W < Start || find(Blocks, W) == Blocks.end()) {
 511         continue;
 512       }
 513       const size_t index = find(Blocked, W) - Blocked.begin();
 514       BlockVector &List = BlockLists[index];
 515       if (find(List, V) == List.end()) {
 516         List.push_back(V);
 517       }
 518     }
 519   }
 520
 521   return FoundCircuit;
 522 }
 523
 524 /// Get the count for the list of blocks which lie on the same line.
 525 void GCOVBlock::getCyclesCount(const BlockVector &Blocks, uint64_t &Count) {
 526   for (auto Block : Blocks) {
 527     Edges Path;
 528     BlockVector Blocked;
 529     BlockVectorLists BlockLists;
 530
 531     GCOVBlock::lookForCircuit(Block, Block, Path, Blocked, BlockLists, Blocks,
 532                               Count);
 533   }
 534 }
 535
 536 /// Get the count for the list of blocks which lie on the same line.
 537 uint64_t GCOVBlock::getLineCount(const BlockVector &Blocks) {
 538   uint64_t Count = 0;
 539
 540   for (auto Block : Blocks) {
 541     if (Block->getNumSrcEdges() == 0) {
 542       // The block has no predecessors and a non-null counter
 543       // (can be the case with entry block in functions).
 544       Count += Block->getCount();
 545     } else {
 546       // Add counts from predecessors that are not on the same line.
 547       for (auto E : Block->srcs()) {
 548         const GCOVBlock *W = &E->Src;
 549         if (find(Blocks, W) == Blocks.end()) {
 550           Count += E->Count;
 551         }
 552       }
 553     }
 554     for (auto E : Block->dsts()) {
 555       E->CyclesCount = E->Count;
 556     }
 557   }
 558
 559   GCOVBlock::getCyclesCount(Blocks, Count);
 560
 561   return Count;
 562 }
 563
 564 //===----------------------------------------------------------------------===//
 565 // FileInfo implementation.
 566
 567 // Safe integer division, returns 0 if numerator is 0.
 568 static uint32_t safeDiv(uint64_t Numerator, uint64_t Divisor) {
 569   if (!Numerator)
 570     return 0;
 571   return Numerator / Divisor;
 572 }
 573
 574 // This custom division function mimics gcov's branch ouputs:
 575 //   - Round to closest whole number
 576 //   - Only output 0% or 100% if it's exactly that value
 577 static uint32_t branchDiv(uint64_t Numerator, uint64_t Divisor) {
 578   if (!Numerator)
 579     return 0;
 580   if (Numerator == Divisor)
 581     return 100;
 582
 583   uint8_t Res = (Numerator * 100 + Divisor / 2) / Divisor;
 584   if (Res == 0)
 585     return 1;
 586   if (Res == 100)
 587     return 99;
 588   return Res;
 589 }
 590
 591 namespace {
 592 struct formatBranchInfo {
 593   formatBranchInfo(const GCOV::Options &Options, uint64_t Count, uint64_t Total)
 594       : Options(Options), Count(Count), Total(Total) {}
 595
 596   void print(raw_ostream &OS) const {
 597     if (!Total)
 598       OS << "never executed";
 599     else if (Options.BranchCount)
 600       OS << "taken " << Count;
 601     else
 602       OS << "taken " << branchDiv(Count, Total) << "%";
 603   }
 604
 605   const GCOV::Options &Options;
 606   uint64_t Count;
 607   uint64_t Total;
 608 };
 609
 610 static raw_ostream &operator<<(raw_ostream &OS, const formatBranchInfo &FBI) {
 611   FBI.print(OS);
 612   return OS;
 613 }
 614
 615 class LineConsumer {
 616   std::unique_ptr<MemoryBuffer> Buffer;
 617   StringRef Remaining;
 618
 619 public:
 620   LineConsumer(StringRef Filename) {
 621     ErrorOr<std::unique_ptr<MemoryBuffer>> BufferOrErr =
 622         MemoryBuffer::getFileOrSTDIN(Filename);
 623     if (std::error_code EC = BufferOrErr.getError()) {
 624       errs() << Filename << ": " << EC.message() << "\n";
 625       Remaining = "";
 626     } else {
 627       Buffer = std::move(BufferOrErr.get());
 628       Remaining = Buffer->getBuffer();
 629     }
 630   }
 631   bool empty() { return Remaining.empty(); }
 632   void printNext(raw_ostream &OS, uint32_t LineNum) {
 633     StringRef Line;
 634     if (empty())
 635       Line = "/*EOF*/";
 636     else
 637       std::tie(Line, Remaining) = Remaining.split("\n");
 638     OS << format("%5u:", LineNum) << Line << "\n";
 639   }
 640 };
 641 } // end anonymous namespace
 642
 643 /// Convert a path to a gcov filename. If PreservePaths is true, this
 644 /// translates "/" to "#", ".." to "^", and drops ".", to match gcov.
 645 static std::string mangleCoveragePath(StringRef Filename, bool PreservePaths) {
 646   if (!PreservePaths)
 647     return sys::path::filename(Filename).str();
 648
 649   // This behaviour is defined by gcov in terms of text replacements, so it's
 650   // not likely to do anything useful on filesystems with different textual
 651   // conventions.
 652   llvm::SmallString<256> Result("");
 653   StringRef::iterator I, S, E;
 654   for (I = S = Filename.begin(), E = Filename.end(); I != E; ++I) {
 655     if (*I != '/')
 656       continue;
 657
 658     if (I - S == 1 && *S == '.') {
 659       // ".", the current directory, is skipped.
 660     } else if (I - S == 2 && *S == '.' && *(S + 1) == '.') {
 661       // "..", the parent directory, is replaced with "^".
 662       Result.append("^#");
 663     } else {
 664       if (S < I)
 665         // Leave other components intact,
 666         Result.append(S, I);
 667       // And separate with "#".
 668       Result.push_back('#');
 669     }
 670     S = I + 1;
 671   }
 672
 673   if (S < I)
 674     Result.append(S, I);
 675   return Result.str();
 676 }
 677
 678 std::string FileInfo::getCoveragePath(StringRef Filename,
 679                                       StringRef MainFilename) {
 680   if (Options.NoOutput)
 681     // This is probably a bug in gcov, but when -n is specified, paths aren't
 682     // mangled at all, and the -l and -p options are ignored. Here, we do the
 683     // same.
 684     return Filename;
 685
 686   std::string CoveragePath;
 687   if (Options.LongFileNames && !Filename.equals(MainFilename))
 688     CoveragePath =
 689         mangleCoveragePath(MainFilename, Options.PreservePaths) + "##";
 690   CoveragePath += mangleCoveragePath(Filename, Options.PreservePaths);
 691   if (Options.HashFilenames) {
 692     MD5 Hasher;
 693     MD5::MD5Result Result;
 694     Hasher.update(Filename.str());
 695     Hasher.final(Result);
 696     CoveragePath += "##" + Result.digest().str().str();
 697   }
 698   CoveragePath += ".gcov";
 699   return CoveragePath;
 700 }
 701
 702 std::unique_ptr<raw_ostream>
 703 FileInfo::openCoveragePath(StringRef CoveragePath) {
 704   if (Options.NoOutput)
 705     return std::make_unique<raw_null_ostream>();
 706
 707   std::error_code EC;
 708   auto OS =
 709       std::make_unique<raw_fd_ostream>(CoveragePath, EC, sys::fs::OF_Text);
 710   if (EC) {
 711     errs() << EC.message() << "\n";
 712     return std::make_unique<raw_null_ostream>();
 713   }
 714   return std::move(OS);
 715 }
 716
 717 /// print -  Print source files with collected line count information.
 718 void FileInfo::print(raw_ostream &InfoOS, StringRef MainFilename,
 719                      StringRef GCNOFile, StringRef GCDAFile) {
 720   SmallVector<StringRef, 4> Filenames;
 721   for (const auto &LI : LineInfo)
 722     Filenames.push_back(LI.first());
 723   llvm::sort(Filenames);
 724
 725   for (StringRef Filename : Filenames) {
 726     auto AllLines = LineConsumer(Filename);
 727
 728     std::string CoveragePath = getCoveragePath(Filename, MainFilename);
 729     std::unique_ptr<raw_ostream> CovStream = openCoveragePath(CoveragePath);
 730     raw_ostream &CovOS = *CovStream;
 731
 732     CovOS << "        -:    0:Source:" << Filename << "\n";
 733     CovOS << "        -:    0:Graph:" << GCNOFile << "\n";
 734     CovOS << "        -:    0:Data:" << GCDAFile << "\n";
 735     CovOS << "        -:    0:Runs:" << RunCount << "\n";
 736     CovOS << "        -:    0:Programs:" << ProgramCount << "\n";
 737
 738     const LineData &Line = LineInfo[Filename];
 739     GCOVCoverage FileCoverage(Filename);
 740     for (uint32_t LineIndex = 0; LineIndex < Line.LastLine || !AllLines.empty();
 741          ++LineIndex) {
 742       if (Options.BranchInfo) {
 743         FunctionLines::const_iterator FuncsIt = Line.Functions.find(LineIndex);
 744         if (FuncsIt != Line.Functions.end())
 745           printFunctionSummary(CovOS, FuncsIt->second);
 746       }
 747
 748       BlockLines::const_iterator BlocksIt = Line.Blocks.find(LineIndex);
 749       if (BlocksIt == Line.Blocks.end()) {
 750         // No basic blocks are on this line. Not an executable line of code.
 751         CovOS << "        -:";
 752         AllLines.printNext(CovOS, LineIndex + 1);
 753       } else {
 754         const BlockVector &Blocks = BlocksIt->second;
 755
 756         // Add up the block counts to form line counts.
 757         DenseMap<const GCOVFunction *, bool> LineExecs;
 758         for (const GCOVBlock *Block : Blocks) {
 759           if (Options.FuncCoverage) {
 760             // This is a slightly convoluted way to most accurately gather line
 761             // statistics for functions. Basically what is happening is that we
 762             // don't want to count a single line with multiple blocks more than
 763             // once. However, we also don't simply want to give the total line
 764             // count to every function that starts on the line. Thus, what is
 765             // happening here are two things:
 766             // 1) Ensure that the number of logical lines is only incremented
 767             //    once per function.
 768             // 2) If there are multiple blocks on the same line, ensure that the
 769             //    number of lines executed is incremented as long as at least
 770             //    one of the blocks are executed.
 771             const GCOVFunction *Function = &Block->getParent();
 772             if (FuncCoverages.find(Function) == FuncCoverages.end()) {
 773               std::pair<const GCOVFunction *, GCOVCoverage> KeyValue(
 774                   Function, GCOVCoverage(Function->getName()));
 775               FuncCoverages.insert(KeyValue);
 776             }
 777             GCOVCoverage &FuncCoverage = FuncCoverages.find(Function)->second;
 778
 779             if (LineExecs.find(Function) == LineExecs.end()) {
 780               if (Block->getCount()) {
 781                 ++FuncCoverage.LinesExec;
 782                 LineExecs[Function] = true;
 783               } else {
 784                 LineExecs[Function] = false;
 785               }
 786               ++FuncCoverage.LogicalLines;
 787             } else if (!LineExecs[Function] && Block->getCount()) {
 788               ++FuncCoverage.LinesExec;
 789               LineExecs[Function] = true;
 790             }
 791           }
 792         }
 793
 794         const uint64_t LineCount = GCOVBlock::getLineCount(Blocks);
 795         if (LineCount == 0)
 796           CovOS << "    #####:";
 797         else {
 798           CovOS << format("%9" PRIu64 ":", LineCount);
 799           ++FileCoverage.LinesExec;
 800         }
 801         ++FileCoverage.LogicalLines;
 802
 803         AllLines.printNext(CovOS, LineIndex + 1);
 804
 805         uint32_t BlockNo = 0;
 806         uint32_t EdgeNo = 0;
 807         for (const GCOVBlock *Block : Blocks) {
 808           // Only print block and branch information at the end of the block.
 809           if (Block->getLastLine() != LineIndex + 1)
 810             continue;
 811           if (Options.AllBlocks)
 812             printBlockInfo(CovOS, *Block, LineIndex, BlockNo);
 813           if (Options.BranchInfo) {
 814             size_t NumEdges = Block->getNumDstEdges();
 815             if (NumEdges > 1)
 816               printBranchInfo(CovOS, *Block, FileCoverage, EdgeNo);
 817             else if (Options.UncondBranch && NumEdges == 1)
 818               printUncondBranchInfo(CovOS, EdgeNo,
 819                                     (*Block->dst_begin())->Count);
 820           }
 821         }
 822       }
 823     }
 824     FileCoverages.push_back(std::make_pair(CoveragePath, FileCoverage));
 825   }
 826
 827   // FIXME: There is no way to detect calls given current instrumentation.
 828   if (Options.FuncCoverage)
 829     printFuncCoverage(InfoOS);
 830   printFileCoverage(InfoOS);
 831 }
 832
 833 /// printFunctionSummary - Print function and block summary.
 834 void FileInfo::printFunctionSummary(raw_ostream &OS,
 835                                     const FunctionVector &Funcs) const {
 836   for (const GCOVFunction *Func : Funcs) {
 837     uint64_t EntryCount = Func->getEntryCount();
 838     uint32_t BlocksExec = 0;
 839     for (const GCOVBlock &Block : Func->blocks())
 840       if (Block.getNumDstEdges() && Block.getCount())
 841         ++BlocksExec;
 842
 843     OS << "function " << Func->getName() << " called " << EntryCount
 844        << " returned " << safeDiv(Func->getExitCount() * 100, EntryCount)
 845        << "% blocks executed "
 846        << safeDiv(BlocksExec * 100, Func->getNumBlocks() - 1) << "%\n";
 847   }
 848 }
 849
 850 /// printBlockInfo - Output counts for each block.
 851 void FileInfo::printBlockInfo(raw_ostream &OS, const GCOVBlock &Block,
 852                               uint32_t LineIndex, uint32_t &BlockNo) const {
 853   if (Block.getCount() == 0)
 854     OS << "    $$$$$:";
 855   else
 856     OS << format("%9" PRIu64 ":", Block.getCount());
 857   OS << format("%5u-block %2u\n", LineIndex + 1, BlockNo++);
 858 }
 859
 860 /// printBranchInfo - Print conditional branch probabilities.
 861 void FileInfo::printBranchInfo(raw_ostream &OS, const GCOVBlock &Block,
 862                                GCOVCoverage &Coverage, uint32_t &EdgeNo) {
 863   SmallVector<uint64_t, 16> BranchCounts;
 864   uint64_t TotalCounts = 0;
 865   for (const GCOVEdge *Edge : Block.dsts()) {
 866     BranchCounts.push_back(Edge->Count);
 867     TotalCounts += Edge->Count;
 868     if (Block.getCount())
 869       ++Coverage.BranchesExec;
 870     if (Edge->Count)
 871       ++Coverage.BranchesTaken;
 872     ++Coverage.Branches;
 873
 874     if (Options.FuncCoverage) {
 875       const GCOVFunction *Function = &Block.getParent();
 876       GCOVCoverage &FuncCoverage = FuncCoverages.find(Function)->second;
 877       if (Block.getCount())
 878         ++FuncCoverage.BranchesExec;
 879       if (Edge->Count)
 880         ++FuncCoverage.BranchesTaken;
 881       ++FuncCoverage.Branches;
 882     }
 883   }
 884
 885   for (uint64_t N : BranchCounts)
 886     OS << format("branch %2u ", EdgeNo++)
 887        << formatBranchInfo(Options, N, TotalCounts) << "\n";
 888 }
 889
 890 /// printUncondBranchInfo - Print unconditional branch probabilities.
 891 void FileInfo::printUncondBranchInfo(raw_ostream &OS, uint32_t &EdgeNo,
 892                                      uint64_t Count) const {
 893   OS << format("unconditional %2u ", EdgeNo++)
 894      << formatBranchInfo(Options, Count, Count) << "\n";
 895 }
 896
 897 // printCoverage - Print generic coverage info used by both printFuncCoverage
 898 // and printFileCoverage.
 899 void FileInfo::printCoverage(raw_ostream &OS,
 900                              const GCOVCoverage &Coverage) const {
 901   OS << format("Lines executed:%.2f%% of %u\n",
 902                double(Coverage.LinesExec) * 100 / Coverage.LogicalLines,
 903                Coverage.LogicalLines);
 904   if (Options.BranchInfo) {
 905     if (Coverage.Branches) {
 906       OS << format("Branches executed:%.2f%% of %u\n",
 907                    double(Coverage.BranchesExec) * 100 / Coverage.Branches,
 908                    Coverage.Branches);
 909       OS << format("Taken at least once:%.2f%% of %u\n",
 910                    double(Coverage.BranchesTaken) * 100 / Coverage.Branches,
 911                    Coverage.Branches);
 912     } else {
 913       OS << "No branches\n";
 914     }
 915     OS << "No calls\n"; // to be consistent with gcov
 916   }
 917 }
 918
 919 // printFuncCoverage - Print per-function coverage info.
 920 void FileInfo::printFuncCoverage(raw_ostream &OS) const {
 921   for (const auto &FC : FuncCoverages) {
 922     const GCOVCoverage &Coverage = FC.second;
 923     OS << "Function '" << Coverage.Name << "'\n";
 924     printCoverage(OS, Coverage);
 925     OS << "\n";
 926   }
 927 }
 928
 929 // printFileCoverage - Print per-file coverage info.
 930 void FileInfo::printFileCoverage(raw_ostream &OS) const {
 931   for (const auto &FC : FileCoverages) {
 932     const std::string &Filename = FC.first;
 933     const GCOVCoverage &Coverage = FC.second;
 934     OS << "File '" << Coverage.Name << "'\n";
 935     printCoverage(OS, Coverage);
 936     if (!Options.NoOutput)
 937       OS << Coverage.Name << ":creating '" << Filename << "'\n";
 938     OS << "\n";
 939   }
 940 }