lib/ProfileData/Coverage/CoverageMappingReader.cpp

   1 //===- CoverageMappingReader.cpp - Code coverage mapping reader -----------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file contains support for reading coverage mapping data for
  11 // instrumentation based coverage.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "llvm/ProfileData/Coverage/CoverageMappingReader.h"
  16 #include "llvm/ADT/ArrayRef.h"
  17 #include "llvm/ADT/DenseMap.h"
  18 #include "llvm/ADT/STLExtras.h"
  19 #include "llvm/ADT/SmallVector.h"
  20 #include "llvm/ADT/StringRef.h"
  21 #include "llvm/ADT/Triple.h"
  22 #include "llvm/Object/Binary.h"
  23 #include "llvm/Object/Error.h"
  24 #include "llvm/Object/MachOUniversal.h"
  25 #include "llvm/Object/ObjectFile.h"
  26 #include "llvm/ProfileData/InstrProf.h"
  27 #include "llvm/Support/Casting.h"
  28 #include "llvm/Support/Debug.h"
  29 #include "llvm/Support/Endian.h"
  30 #include "llvm/Support/Error.h"
  31 #include "llvm/Support/ErrorHandling.h"
  32 #include "llvm/Support/LEB128.h"
  33 #include "llvm/Support/MathExtras.h"
  34 #include "llvm/Support/raw_ostream.h"
  35 #include <vector>
  36
  37 using namespace llvm;
  38 using namespace coverage;
  39 using namespace object;
  40
  41 #define DEBUG_TYPE "coverage-mapping"
  42
  43 void CoverageMappingIterator::increment() {
  44   if (ReadErr != coveragemap_error::success)
  45     return;
  46
  47   // Check if all the records were read or if an error occurred while reading
  48   // the next record.
  49   if (auto E = Reader->readNextRecord(Record))
  50     handleAllErrors(std::move(E), [&](const CoverageMapError &CME) {
  51       if (CME.get() == coveragemap_error::eof)
  52         *this = CoverageMappingIterator();
  53       else
  54         ReadErr = CME.get();
  55     });
  56 }
  57
  58 Error RawCoverageReader::readULEB128(uint64_t &Result) {
  59   if (Data.empty())
  60     return make_error<CoverageMapError>(coveragemap_error::truncated);
  61   unsigned N = 0;
  62   Result = decodeULEB128(reinterpret_cast<const uint8_t *>(Data.data()), &N);
  63   if (N > Data.size())
  64     return make_error<CoverageMapError>(coveragemap_error::malformed);
  65   Data = Data.substr(N);
  66   return Error::success();
  67 }
  68
  69 Error RawCoverageReader::readIntMax(uint64_t &Result, uint64_t MaxPlus1) {
  70   if (auto Err = readULEB128(Result))
  71     return Err;
  72   if (Result >= MaxPlus1)
  73     return make_error<CoverageMapError>(coveragemap_error::malformed);
  74   return Error::success();
  75 }
  76
  77 Error RawCoverageReader::readSize(uint64_t &Result) {
  78   if (auto Err = readULEB128(Result))
  79     return Err;
  80   // Sanity check the number.
  81   if (Result > Data.size())
  82     return make_error<CoverageMapError>(coveragemap_error::malformed);
  83   return Error::success();
  84 }
  85
  86 Error RawCoverageReader::readString(StringRef &Result) {
  87   uint64_t Length;
  88   if (auto Err = readSize(Length))
  89     return Err;
  90   Result = Data.substr(0, Length);
  91   Data = Data.substr(Length);
  92   return Error::success();
  93 }
  94
  95 Error RawCoverageFilenamesReader::read() {
  96   uint64_t NumFilenames;
  97   if (auto Err = readSize(NumFilenames))
  98     return Err;
  99   for (size_t I = 0; I < NumFilenames; ++I) {
 100     StringRef Filename;
 101     if (auto Err = readString(Filename))
 102       return Err;
 103     Filenames.push_back(Filename);
 104   }
 105   return Error::success();
 106 }
 107
 108 Error RawCoverageMappingReader::decodeCounter(unsigned Value, Counter &C) {
 109   auto Tag = Value & Counter::EncodingTagMask;
 110   switch (Tag) {
 111   case Counter::Zero:
 112     C = Counter::getZero();
 113     return Error::success();
 114   case Counter::CounterValueReference:
 115     C = Counter::getCounter(Value >> Counter::EncodingTagBits);
 116     return Error::success();
 117   default:
 118     break;
 119   }
 120   Tag -= Counter::Expression;
 121   switch (Tag) {
 122   case CounterExpression::Subtract:
 123   case CounterExpression::Add: {
 124     auto ID = Value >> Counter::EncodingTagBits;
 125     if (ID >= Expressions.size())
 126       return make_error<CoverageMapError>(coveragemap_error::malformed);
 127     Expressions[ID].Kind = CounterExpression::ExprKind(Tag);
 128     C = Counter::getExpression(ID);
 129     break;
 130   }
 131   default:
 132     return make_error<CoverageMapError>(coveragemap_error::malformed);
 133   }
 134   return Error::success();
 135 }
 136
 137 Error RawCoverageMappingReader::readCounter(Counter &C) {
 138   uint64_t EncodedCounter;
 139   if (auto Err =
 140           readIntMax(EncodedCounter, std::numeric_limits<unsigned>::max()))
 141     return Err;
 142   if (auto Err = decodeCounter(EncodedCounter, C))
 143     return Err;
 144   return Error::success();
 145 }
 146
 147 static const unsigned EncodingExpansionRegionBit = 1
 148                                                    << Counter::EncodingTagBits;
 149
 150 /// Read the sub-array of regions for the given inferred file id.
 151 /// \param NumFileIDs the number of file ids that are defined for this
 152 /// function.
 153 Error RawCoverageMappingReader::readMappingRegionsSubArray(
 154     std::vector<CounterMappingRegion> &MappingRegions, unsigned InferredFileID,
 155     size_t NumFileIDs) {
 156   uint64_t NumRegions;
 157   if (auto Err = readSize(NumRegions))
 158     return Err;
 159   unsigned LineStart = 0;
 160   for (size_t I = 0; I < NumRegions; ++I) {
 161     Counter C;
 162     CounterMappingRegion::RegionKind Kind = CounterMappingRegion::CodeRegion;
 163
 164     // Read the combined counter + region kind.
 165     uint64_t EncodedCounterAndRegion;
 166     if (auto Err = readIntMax(EncodedCounterAndRegion,
 167                               std::numeric_limits<unsigned>::max()))
 168       return Err;
 169     unsigned Tag = EncodedCounterAndRegion & Counter::EncodingTagMask;
 170     uint64_t ExpandedFileID = 0;
 171     if (Tag != Counter::Zero) {
 172       if (auto Err = decodeCounter(EncodedCounterAndRegion, C))
 173         return Err;
 174     } else {
 175       // Is it an expansion region?
 176       if (EncodedCounterAndRegion & EncodingExpansionRegionBit) {
 177         Kind = CounterMappingRegion::ExpansionRegion;
 178         ExpandedFileID = EncodedCounterAndRegion >>
 179                          Counter::EncodingCounterTagAndExpansionRegionTagBits;
 180         if (ExpandedFileID >= NumFileIDs)
 181           return make_error<CoverageMapError>(coveragemap_error::malformed);
 182       } else {
 183         switch (EncodedCounterAndRegion >>
 184                 Counter::EncodingCounterTagAndExpansionRegionTagBits) {
 185         case CounterMappingRegion::CodeRegion:
 186           // Don't do anything when we have a code region with a zero counter.
 187           break;
 188         case CounterMappingRegion::SkippedRegion:
 189           Kind = CounterMappingRegion::SkippedRegion;
 190           break;
 191         default:
 192           return make_error<CoverageMapError>(coveragemap_error::malformed);
 193         }
 194       }
 195     }
 196
 197     // Read the source range.
 198     uint64_t LineStartDelta, ColumnStart, NumLines, ColumnEnd;
 199     if (auto Err =
 200             readIntMax(LineStartDelta, std::numeric_limits<unsigned>::max()))
 201       return Err;
 202     if (auto Err = readULEB128(ColumnStart))
 203       return Err;
 204     if (ColumnStart > std::numeric_limits<unsigned>::max())
 205       return make_error<CoverageMapError>(coveragemap_error::malformed);
 206     if (auto Err = readIntMax(NumLines, std::numeric_limits<unsigned>::max()))
 207       return Err;
 208     if (auto Err = readIntMax(ColumnEnd, std::numeric_limits<unsigned>::max()))
 209       return Err;
 210     LineStart += LineStartDelta;
 211
 212     // If the high bit of ColumnEnd is set, this is a gap region.
 213     if (ColumnEnd & (1U << 31)) {
 214       Kind = CounterMappingRegion::GapRegion;
 215       ColumnEnd &= ~(1U << 31);
 216     }
 217
 218     // Adjust the column locations for the empty regions that are supposed to
 219     // cover whole lines. Those regions should be encoded with the
 220     // column range (1 -> std::numeric_limits<unsigned>::max()), but because
 221     // the encoded std::numeric_limits<unsigned>::max() is several bytes long,
 222     // we set the column range to (0 -> 0) to ensure that the column start and
 223     // column end take up one byte each.
 224     // The std::numeric_limits<unsigned>::max() is used to represent a column
 225     // position at the end of the line without knowing the length of that line.
 226     if (ColumnStart == 0 && ColumnEnd == 0) {
 227       ColumnStart = 1;
 228       ColumnEnd = std::numeric_limits<unsigned>::max();
 229     }
 230
 231     LLVM_DEBUG({
 232       dbgs() << "Counter in file " << InferredFileID << " " << LineStart << ":"
 233              << ColumnStart << " -> " << (LineStart + NumLines) << ":"
 234              << ColumnEnd << ", ";
 235       if (Kind == CounterMappingRegion::ExpansionRegion)
 236         dbgs() << "Expands to file " << ExpandedFileID;
 237       else
 238         CounterMappingContext(Expressions).dump(C, dbgs());
 239       dbgs() << "\n";
 240     });
 241
 242     auto CMR = CounterMappingRegion(C, InferredFileID, ExpandedFileID,
 243                                     LineStart, ColumnStart,
 244                                     LineStart + NumLines, ColumnEnd, Kind);
 245     if (CMR.startLoc() > CMR.endLoc())
 246       return make_error<CoverageMapError>(coveragemap_error::malformed);
 247     MappingRegions.push_back(CMR);
 248   }
 249   return Error::success();
 250 }
 251
 252 Error RawCoverageMappingReader::read() {
 253   // Read the virtual file mapping.
 254   SmallVector<unsigned, 8> VirtualFileMapping;
 255   uint64_t NumFileMappings;
 256   if (auto Err = readSize(NumFileMappings))
 257     return Err;
 258   for (size_t I = 0; I < NumFileMappings; ++I) {
 259     uint64_t FilenameIndex;
 260     if (auto Err = readIntMax(FilenameIndex, TranslationUnitFilenames.size()))
 261       return Err;
 262     VirtualFileMapping.push_back(FilenameIndex);
 263   }
 264
 265   // Construct the files using unique filenames and virtual file mapping.
 266   for (auto I : VirtualFileMapping) {
 267     Filenames.push_back(TranslationUnitFilenames[I]);
 268   }
 269
 270   // Read the expressions.
 271   uint64_t NumExpressions;
 272   if (auto Err = readSize(NumExpressions))
 273     return Err;
 274   // Create an array of dummy expressions that get the proper counters
 275   // when the expressions are read, and the proper kinds when the counters
 276   // are decoded.
 277   Expressions.resize(
 278       NumExpressions,
 279       CounterExpression(CounterExpression::Subtract, Counter(), Counter()));
 280   for (size_t I = 0; I < NumExpressions; ++I) {
 281     if (auto Err = readCounter(Expressions[I].LHS))
 282       return Err;
 283     if (auto Err = readCounter(Expressions[I].RHS))
 284       return Err;
 285   }
 286
 287   // Read the mapping regions sub-arrays.
 288   for (unsigned InferredFileID = 0, S = VirtualFileMapping.size();
 289        InferredFileID < S; ++InferredFileID) {
 290     if (auto Err = readMappingRegionsSubArray(MappingRegions, InferredFileID,
 291                                               VirtualFileMapping.size()))
 292       return Err;
 293   }
 294
 295   // Set the counters for the expansion regions.
 296   // i.e. Counter of expansion region = counter of the first region
 297   // from the expanded file.
 298   // Perform multiple passes to correctly propagate the counters through
 299   // all the nested expansion regions.
 300   SmallVector<CounterMappingRegion *, 8> FileIDExpansionRegionMapping;
 301   FileIDExpansionRegionMapping.resize(VirtualFileMapping.size(), nullptr);
 302   for (unsigned Pass = 1, S = VirtualFileMapping.size(); Pass < S; ++Pass) {
 303     for (auto &R : MappingRegions) {
 304       if (R.Kind != CounterMappingRegion::ExpansionRegion)
 305         continue;
 306       assert(!FileIDExpansionRegionMapping[R.ExpandedFileID]);
 307       FileIDExpansionRegionMapping[R.ExpandedFileID] = &R;
 308     }
 309     for (auto &R : MappingRegions) {
 310       if (FileIDExpansionRegionMapping[R.FileID]) {
 311         FileIDExpansionRegionMapping[R.FileID]->Count = R.Count;
 312         FileIDExpansionRegionMapping[R.FileID] = nullptr;
 313       }
 314     }
 315   }
 316
 317   return Error::success();
 318 }
 319
 320 Expected<bool> RawCoverageMappingDummyChecker::isDummy() {
 321   // A dummy coverage mapping data consists of just one region with zero count.
 322   uint64_t NumFileMappings;
 323   if (Error Err = readSize(NumFileMappings))
 324     return std::move(Err);
 325   if (NumFileMappings != 1)
 326     return false;
 327   // We don't expect any specific value for the filename index, just skip it.
 328   uint64_t FilenameIndex;
 329   if (Error Err =
 330           readIntMax(FilenameIndex, std::numeric_limits<unsigned>::max()))
 331     return std::move(Err);
 332   uint64_t NumExpressions;
 333   if (Error Err = readSize(NumExpressions))
 334     return std::move(Err);
 335   if (NumExpressions != 0)
 336     return false;
 337   uint64_t NumRegions;
 338   if (Error Err = readSize(NumRegions))
 339     return std::move(Err);
 340   if (NumRegions != 1)
 341     return false;
 342   uint64_t EncodedCounterAndRegion;
 343   if (Error Err = readIntMax(EncodedCounterAndRegion,
 344                              std::numeric_limits<unsigned>::max()))
 345     return std::move(Err);
 346   unsigned Tag = EncodedCounterAndRegion & Counter::EncodingTagMask;
 347   return Tag == Counter::Zero;
 348 }
 349
 350 Error InstrProfSymtab::create(SectionRef &Section) {
 351   if (auto EC = Section.getContents(Data))
 352     return errorCodeToError(EC);
 353   Address = Section.getAddress();
 354   return Error::success();
 355 }
 356
 357 StringRef InstrProfSymtab::getFuncName(uint64_t Pointer, size_t Size) {
 358   if (Pointer < Address)
 359     return StringRef();
 360   auto Offset = Pointer - Address;
 361   if (Offset + Size > Data.size())
 362     return StringRef();
 363   return Data.substr(Pointer - Address, Size);
 364 }
 365
 366 // Check if the mapping data is a dummy, i.e. is emitted for an unused function.
 367 static Expected<bool> isCoverageMappingDummy(uint64_t Hash, StringRef Mapping) {
 368   // The hash value of dummy mapping records is always zero.
 369   if (Hash)
 370     return false;
 371   return RawCoverageMappingDummyChecker(Mapping).isDummy();
 372 }
 373
 374 namespace {
 375
 376 struct CovMapFuncRecordReader {
 377   virtual ~CovMapFuncRecordReader() = default;
 378
 379   // The interface to read coverage mapping function records for a module.
 380   //
 381   // \p Buf points to the buffer containing the \c CovHeader of the coverage
 382   // mapping data associated with the module.
 383   //
 384   // Returns a pointer to the next \c CovHeader if it exists, or a pointer
 385   // greater than \p End if not.
 386   virtual Expected<const char *> readFunctionRecords(const char *Buf,
 387                                                      const char *End) = 0;
 388
 389   template <class IntPtrT, support::endianness Endian>
 390   static Expected<std::unique_ptr<CovMapFuncRecordReader>>
 391   get(CovMapVersion Version, InstrProfSymtab &P,
 392       std::vector<BinaryCoverageReader::ProfileMappingRecord> &R,
 393       std::vector<StringRef> &F);
 394 };
 395
 396 // A class for reading coverage mapping function records for a module.
 397 template <CovMapVersion Version, class IntPtrT, support::endianness Endian>
 398 class VersionedCovMapFuncRecordReader : public CovMapFuncRecordReader {
 399   using FuncRecordType =
 400       typename CovMapTraits<Version, IntPtrT>::CovMapFuncRecordType;
 401   using NameRefType = typename CovMapTraits<Version, IntPtrT>::NameRefType;
 402
 403   // Maps function's name references to the indexes of their records
 404   // in \c Records.
 405   DenseMap<NameRefType, size_t> FunctionRecords;
 406   InstrProfSymtab &ProfileNames;
 407   std::vector<StringRef> &Filenames;
 408   std::vector<BinaryCoverageReader::ProfileMappingRecord> &Records;
 409
 410   // Add the record to the collection if we don't already have a record that
 411   // points to the same function name. This is useful to ignore the redundant
 412   // records for the functions with ODR linkage.
 413   // In addition, prefer records with real coverage mapping data to dummy
 414   // records, which were emitted for inline functions which were seen but
 415   // not used in the corresponding translation unit.
 416   Error insertFunctionRecordIfNeeded(const FuncRecordType *CFR,
 417                                      StringRef Mapping, size_t FilenamesBegin) {
 418     uint64_t FuncHash = CFR->template getFuncHash<Endian>();
 419     NameRefType NameRef = CFR->template getFuncNameRef<Endian>();
 420     auto InsertResult =
 421         FunctionRecords.insert(std::make_pair(NameRef, Records.size()));
 422     if (InsertResult.second) {
 423       StringRef FuncName;
 424       if (Error Err = CFR->template getFuncName<Endian>(ProfileNames, FuncName))
 425         return Err;
 426       if (FuncName.empty())
 427         return make_error<InstrProfError>(instrprof_error::malformed);
 428       Records.emplace_back(Version, FuncName, FuncHash, Mapping, FilenamesBegin,
 429                            Filenames.size() - FilenamesBegin);
 430       return Error::success();
 431     }
 432     // Update the existing record if it's a dummy and the new record is real.
 433     size_t OldRecordIndex = InsertResult.first->second;
 434     BinaryCoverageReader::ProfileMappingRecord &OldRecord =
 435         Records[OldRecordIndex];
 436     Expected<bool> OldIsDummyExpected = isCoverageMappingDummy(
 437         OldRecord.FunctionHash, OldRecord.CoverageMapping);
 438     if (Error Err = OldIsDummyExpected.takeError())
 439       return Err;
 440     if (!*OldIsDummyExpected)
 441       return Error::success();
 442     Expected<bool> NewIsDummyExpected =
 443         isCoverageMappingDummy(FuncHash, Mapping);
 444     if (Error Err = NewIsDummyExpected.takeError())
 445       return Err;
 446     if (*NewIsDummyExpected)
 447       return Error::success();
 448     OldRecord.FunctionHash = FuncHash;
 449     OldRecord.CoverageMapping = Mapping;
 450     OldRecord.FilenamesBegin = FilenamesBegin;
 451     OldRecord.FilenamesSize = Filenames.size() - FilenamesBegin;
 452     return Error::success();
 453   }
 454
 455 public:
 456   VersionedCovMapFuncRecordReader(
 457       InstrProfSymtab &P,
 458       std::vector<BinaryCoverageReader::ProfileMappingRecord> &R,
 459       std::vector<StringRef> &F)
 460       : ProfileNames(P), Filenames(F), Records(R) {}
 461
 462   ~VersionedCovMapFuncRecordReader() override = default;
 463
 464   Expected<const char *> readFunctionRecords(const char *Buf,
 465                                              const char *End) override {
 466     using namespace support;
 467
 468     if (Buf + sizeof(CovMapHeader) > End)
 469       return make_error<CoverageMapError>(coveragemap_error::malformed);
 470     auto CovHeader = reinterpret_cast<const CovMapHeader *>(Buf);
 471     uint32_t NRecords = CovHeader->getNRecords<Endian>();
 472     uint32_t FilenamesSize = CovHeader->getFilenamesSize<Endian>();
 473     uint32_t CoverageSize = CovHeader->getCoverageSize<Endian>();
 474     assert((CovMapVersion)CovHeader->getVersion<Endian>() == Version);
 475     Buf = reinterpret_cast<const char *>(CovHeader + 1);
 476
 477     // Skip past the function records, saving the start and end for later.
 478     const char *FunBuf = Buf;
 479     Buf += NRecords * sizeof(FuncRecordType);
 480     const char *FunEnd = Buf;
 481
 482     // Get the filenames.
 483     if (Buf + FilenamesSize > End)
 484       return make_error<CoverageMapError>(coveragemap_error::malformed);
 485     size_t FilenamesBegin = Filenames.size();
 486     RawCoverageFilenamesReader Reader(StringRef(Buf, FilenamesSize), Filenames);
 487     if (auto Err = Reader.read())
 488       return std::move(Err);
 489     Buf += FilenamesSize;
 490
 491     // We'll read the coverage mapping records in the loop below.
 492     const char *CovBuf = Buf;
 493     Buf += CoverageSize;
 494     const char *CovEnd = Buf;
 495
 496     if (Buf > End)
 497       return make_error<CoverageMapError>(coveragemap_error::malformed);
 498     // Each coverage map has an alignment of 8, so we need to adjust alignment
 499     // before reading the next map.
 500     Buf += alignmentAdjustment(Buf, 8);
 501
 502     auto CFR = reinterpret_cast<const FuncRecordType *>(FunBuf);
 503     while ((const char *)CFR < FunEnd) {
 504       // Read the function information
 505       uint32_t DataSize = CFR->template getDataSize<Endian>();
 506
 507       // Now use that to read the coverage data.
 508       if (CovBuf + DataSize > CovEnd)
 509         return make_error<CoverageMapError>(coveragemap_error::malformed);
 510       auto Mapping = StringRef(CovBuf, DataSize);
 511       CovBuf += DataSize;
 512
 513       if (Error Err =
 514               insertFunctionRecordIfNeeded(CFR, Mapping, FilenamesBegin))
 515         return std::move(Err);
 516       CFR++;
 517     }
 518     return Buf;
 519   }
 520 };
 521
 522 } // end anonymous namespace
 523
 524 template <class IntPtrT, support::endianness Endian>
 525 Expected<std::unique_ptr<CovMapFuncRecordReader>> CovMapFuncRecordReader::get(
 526     CovMapVersion Version, InstrProfSymtab &P,
 527     std::vector<BinaryCoverageReader::ProfileMappingRecord> &R,
 528     std::vector<StringRef> &F) {
 529   using namespace coverage;
 530
 531   switch (Version) {
 532   case CovMapVersion::Version1:
 533     return llvm::make_unique<VersionedCovMapFuncRecordReader<
 534         CovMapVersion::Version1, IntPtrT, Endian>>(P, R, F);
 535   case CovMapVersion::Version2:
 536   case CovMapVersion::Version3:
 537     // Decompress the name data.
 538     if (Error E = P.create(P.getNameData()))
 539       return std::move(E);
 540     if (Version == CovMapVersion::Version2)
 541       return llvm::make_unique<VersionedCovMapFuncRecordReader<
 542           CovMapVersion::Version2, IntPtrT, Endian>>(P, R, F);
 543     else
 544       return llvm::make_unique<VersionedCovMapFuncRecordReader<
 545           CovMapVersion::Version3, IntPtrT, Endian>>(P, R, F);
 546   }
 547   llvm_unreachable("Unsupported version");
 548 }
 549
 550 template <typename T, support::endianness Endian>
 551 static Error readCoverageMappingData(
 552     InstrProfSymtab &ProfileNames, StringRef Data,
 553     std::vector<BinaryCoverageReader::ProfileMappingRecord> &Records,
 554     std::vector<StringRef> &Filenames) {
 555   using namespace coverage;
 556
 557   // Read the records in the coverage data section.
 558   auto CovHeader =
 559       reinterpret_cast<const CovMapHeader *>(Data.data());
 560   CovMapVersion Version = (CovMapVersion)CovHeader->getVersion<Endian>();
 561   if (Version > CovMapVersion::CurrentVersion)
 562     return make_error<CoverageMapError>(coveragemap_error::unsupported_version);
 563   Expected<std::unique_ptr<CovMapFuncRecordReader>> ReaderExpected =
 564       CovMapFuncRecordReader::get<T, Endian>(Version, ProfileNames, Records,
 565                                              Filenames);
 566   if (Error E = ReaderExpected.takeError())
 567     return E;
 568   auto Reader = std::move(ReaderExpected.get());
 569   for (const char *Buf = Data.data(), *End = Buf + Data.size(); Buf < End;) {
 570     auto NextHeaderOrErr = Reader->readFunctionRecords(Buf, End);
 571     if (auto E = NextHeaderOrErr.takeError())
 572       return E;
 573     Buf = NextHeaderOrErr.get();
 574   }
 575   return Error::success();
 576 }
 577
 578 static const char *TestingFormatMagic = "llvmcovmtestdata";
 579
 580 static Error loadTestingFormat(StringRef Data, InstrProfSymtab &ProfileNames,
 581                                StringRef &CoverageMapping,
 582                                uint8_t &BytesInAddress,
 583                                support::endianness &Endian) {
 584   BytesInAddress = 8;
 585   Endian = support::endianness::little;
 586
 587   Data = Data.substr(StringRef(TestingFormatMagic).size());
 588   if (Data.empty())
 589     return make_error<CoverageMapError>(coveragemap_error::truncated);
 590   unsigned N = 0;
 591   auto ProfileNamesSize =
 592       decodeULEB128(reinterpret_cast<const uint8_t *>(Data.data()), &N);
 593   if (N > Data.size())
 594     return make_error<CoverageMapError>(coveragemap_error::malformed);
 595   Data = Data.substr(N);
 596   if (Data.empty())
 597     return make_error<CoverageMapError>(coveragemap_error::truncated);
 598   N = 0;
 599   uint64_t Address =
 600       decodeULEB128(reinterpret_cast<const uint8_t *>(Data.data()), &N);
 601   if (N > Data.size())
 602     return make_error<CoverageMapError>(coveragemap_error::malformed);
 603   Data = Data.substr(N);
 604   if (Data.size() < ProfileNamesSize)
 605     return make_error<CoverageMapError>(coveragemap_error::malformed);
 606   if (Error E = ProfileNames.create(Data.substr(0, ProfileNamesSize), Address))
 607     return E;
 608   CoverageMapping = Data.substr(ProfileNamesSize);
 609   // Skip the padding bytes because coverage map data has an alignment of 8.
 610   if (CoverageMapping.empty())
 611     return make_error<CoverageMapError>(coveragemap_error::truncated);
 612   size_t Pad = alignmentAdjustment(CoverageMapping.data(), 8);
 613   if (CoverageMapping.size() < Pad)
 614     return make_error<CoverageMapError>(coveragemap_error::malformed);
 615   CoverageMapping = CoverageMapping.substr(Pad);
 616   return Error::success();
 617 }
 618
 619 static Expected<SectionRef> lookupSection(ObjectFile &OF, StringRef Name) {
 620   StringRef FoundName;
 621   for (const auto &Section : OF.sections()) {
 622     if (auto EC = Section.getName(FoundName))
 623       return errorCodeToError(EC);
 624     if (FoundName == Name)
 625       return Section;
 626   }
 627   return make_error<CoverageMapError>(coveragemap_error::no_data_found);
 628 }
 629
 630 static Error loadBinaryFormat(MemoryBufferRef ObjectBuffer,
 631                               InstrProfSymtab &ProfileNames,
 632                               StringRef &CoverageMapping,
 633                               uint8_t &BytesInAddress,
 634                               support::endianness &Endian, StringRef Arch) {
 635   auto BinOrErr = createBinary(ObjectBuffer);
 636   if (!BinOrErr)
 637     return BinOrErr.takeError();
 638   auto Bin = std::move(BinOrErr.get());
 639   std::unique_ptr<ObjectFile> OF;
 640   if (auto *Universal = dyn_cast<MachOUniversalBinary>(Bin.get())) {
 641     // If we have a universal binary, try to look up the object for the
 642     // appropriate architecture.
 643     auto ObjectFileOrErr = Universal->getObjectForArch(Arch);
 644     if (!ObjectFileOrErr)
 645       return ObjectFileOrErr.takeError();
 646     OF = std::move(ObjectFileOrErr.get());
 647   } else if (isa<ObjectFile>(Bin.get())) {
 648     // For any other object file, upcast and take ownership.
 649     OF.reset(cast<ObjectFile>(Bin.release()));
 650     // If we've asked for a particular arch, make sure they match.
 651     if (!Arch.empty() && OF->getArch() != Triple(Arch).getArch())
 652       return errorCodeToError(object_error::arch_not_found);
 653   } else
 654     // We can only handle object files.
 655     return make_error<CoverageMapError>(coveragemap_error::malformed);
 656
 657   // The coverage uses native pointer sizes for the object it's written in.
 658   BytesInAddress = OF->getBytesInAddress();
 659   Endian = OF->isLittleEndian() ? support::endianness::little
 660                                 : support::endianness::big;
 661
 662   // Look for the sections that we are interested in.
 663   auto ObjFormat = OF->getTripleObjectFormat();
 664   auto NamesSection =
 665       lookupSection(*OF, getInstrProfSectionName(IPSK_name, ObjFormat,
 666                                                  /*AddSegmentInfo=*/false));
 667   if (auto E = NamesSection.takeError())
 668     return E;
 669   auto CoverageSection =
 670       lookupSection(*OF, getInstrProfSectionName(IPSK_covmap, ObjFormat,
 671                                                  /*AddSegmentInfo=*/false));
 672   if (auto E = CoverageSection.takeError())
 673     return E;
 674
 675   // Get the contents of the given sections.
 676   if (auto EC = CoverageSection->getContents(CoverageMapping))
 677     return errorCodeToError(EC);
 678   if (Error E = ProfileNames.create(*NamesSection))
 679     return E;
 680
 681   return Error::success();
 682 }
 683
 684 Expected<std::unique_ptr<BinaryCoverageReader>>
 685 BinaryCoverageReader::create(std::unique_ptr<MemoryBuffer> &ObjectBuffer,
 686                              StringRef Arch) {
 687   std::unique_ptr<BinaryCoverageReader> Reader(new BinaryCoverageReader());
 688
 689   StringRef Coverage;
 690   uint8_t BytesInAddress;
 691   support::endianness Endian;
 692   Error E = Error::success();
 693   consumeError(std::move(E));
 694   if (ObjectBuffer->getBuffer().startswith(TestingFormatMagic))
 695     // This is a special format used for testing.
 696     E = loadTestingFormat(ObjectBuffer->getBuffer(), Reader->ProfileNames,
 697                           Coverage, BytesInAddress, Endian);
 698   else
 699     E = loadBinaryFormat(ObjectBuffer->getMemBufferRef(), Reader->ProfileNames,
 700                          Coverage, BytesInAddress, Endian, Arch);
 701   if (E)
 702     return std::move(E);
 703
 704   if (BytesInAddress == 4 && Endian == support::endianness::little)
 705     E = readCoverageMappingData<uint32_t, support::endianness::little>(
 706         Reader->ProfileNames, Coverage, Reader->MappingRecords,
 707         Reader->Filenames);
 708   else if (BytesInAddress == 4 && Endian == support::endianness::big)
 709     E = readCoverageMappingData<uint32_t, support::endianness::big>(
 710         Reader->ProfileNames, Coverage, Reader->MappingRecords,
 711         Reader->Filenames);
 712   else if (BytesInAddress == 8 && Endian == support::endianness::little)
 713     E = readCoverageMappingData<uint64_t, support::endianness::little>(
 714         Reader->ProfileNames, Coverage, Reader->MappingRecords,
 715         Reader->Filenames);
 716   else if (BytesInAddress == 8 && Endian == support::endianness::big)
 717     E = readCoverageMappingData<uint64_t, support::endianness::big>(
 718         Reader->ProfileNames, Coverage, Reader->MappingRecords,
 719         Reader->Filenames);
 720   else
 721     return make_error<CoverageMapError>(coveragemap_error::malformed);
 722   if (E)
 723     return std::move(E);
 724   return std::move(Reader);
 725 }
 726
 727 Error BinaryCoverageReader::readNextRecord(CoverageMappingRecord &Record) {
 728   if (CurrentRecord >= MappingRecords.size())
 729     return make_error<CoverageMapError>(coveragemap_error::eof);
 730
 731   FunctionsFilenames.clear();
 732   Expressions.clear();
 733   MappingRegions.clear();
 734   auto &R = MappingRecords[CurrentRecord];
 735   RawCoverageMappingReader Reader(
 736       R.CoverageMapping,
 737       makeArrayRef(Filenames).slice(R.FilenamesBegin, R.FilenamesSize),
 738       FunctionsFilenames, Expressions, MappingRegions);
 739   if (auto Err = Reader.read())
 740     return Err;
 741
 742   Record.FunctionName = R.FunctionName;
 743   Record.FunctionHash = R.FunctionHash;
 744   Record.Filenames = FunctionsFilenames;
 745   Record.Expressions = Expressions;
 746   Record.MappingRegions = MappingRegions;
 747
 748   ++CurrentRecord;
 749   return Error::success();
 750 }