lib/ProfileData/Coverage/CoverageMapping.cpp

   1 //===- CoverageMapping.cpp - Code coverage mapping support ----------------===//
   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 file contains support for clang's and llvm's instrumentation based
  10 // code coverage.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/ProfileData/Coverage/CoverageMapping.h"
  15 #include "llvm/ADT/ArrayRef.h"
  16 #include "llvm/ADT/DenseMap.h"
  17 #include "llvm/ADT/None.h"
  18 #include "llvm/ADT/Optional.h"
  19 #include "llvm/ADT/SmallBitVector.h"
  20 #include "llvm/ADT/SmallVector.h"
  21 #include "llvm/ADT/StringRef.h"
  22 #include "llvm/ProfileData/Coverage/CoverageMappingReader.h"
  23 #include "llvm/ProfileData/InstrProfReader.h"
  24 #include "llvm/Support/Debug.h"
  25 #include "llvm/Support/Errc.h"
  26 #include "llvm/Support/Error.h"
  27 #include "llvm/Support/ErrorHandling.h"
  28 #include "llvm/Support/ManagedStatic.h"
  29 #include "llvm/Support/MemoryBuffer.h"
  30 #include "llvm/Support/raw_ostream.h"
  31 #include <algorithm>
  32 #include <cassert>
  33 #include <cstdint>
  34 #include <iterator>
  35 #include <map>
  36 #include <memory>
  37 #include <string>
  38 #include <system_error>
  39 #include <utility>
  40 #include <vector>
  41
  42 using namespace llvm;
  43 using namespace coverage;
  44
  45 #define DEBUG_TYPE "coverage-mapping"
  46
  47 Counter CounterExpressionBuilder::get(const CounterExpression &E) {
  48   auto It = ExpressionIndices.find(E);
  49   if (It != ExpressionIndices.end())
  50     return Counter::getExpression(It->second);
  51   unsigned I = Expressions.size();
  52   Expressions.push_back(E);
  53   ExpressionIndices[E] = I;
  54   return Counter::getExpression(I);
  55 }
  56
  57 void CounterExpressionBuilder::extractTerms(Counter C, int Factor,
  58                                             SmallVectorImpl<Term> &Terms) {
  59   switch (C.getKind()) {
  60   case Counter::Zero:
  61     break;
  62   case Counter::CounterValueReference:
  63     Terms.emplace_back(C.getCounterID(), Factor);
  64     break;
  65   case Counter::Expression:
  66     const auto &E = Expressions[C.getExpressionID()];
  67     extractTerms(E.LHS, Factor, Terms);
  68     extractTerms(
  69         E.RHS, E.Kind == CounterExpression::Subtract ? -Factor : Factor, Terms);
  70     break;
  71   }
  72 }
  73
  74 Counter CounterExpressionBuilder::simplify(Counter ExpressionTree) {
  75   // Gather constant terms.
  76   SmallVector<Term, 32> Terms;
  77   extractTerms(ExpressionTree, +1, Terms);
  78
  79   // If there are no terms, this is just a zero. The algorithm below assumes at
  80   // least one term.
  81   if (Terms.size() == 0)
  82     return Counter::getZero();
  83
  84   // Group the terms by counter ID.
  85   llvm::sort(Terms, [](const Term &LHS, const Term &RHS) {
  86     return LHS.CounterID < RHS.CounterID;
  87   });
  88
  89   // Combine terms by counter ID to eliminate counters that sum to zero.
  90   auto Prev = Terms.begin();
  91   for (auto I = Prev + 1, E = Terms.end(); I != E; ++I) {
  92     if (I->CounterID == Prev->CounterID) {
  93       Prev->Factor += I->Factor;
  94       continue;
  95     }
  96     ++Prev;
  97     *Prev = *I;
  98   }
  99   Terms.erase(++Prev, Terms.end());
 100
 101   Counter C;
 102   // Create additions. We do this before subtractions to avoid constructs like
 103   // ((0 - X) + Y), as opposed to (Y - X).
 104   for (auto T : Terms) {
 105     if (T.Factor <= 0)
 106       continue;
 107     for (int I = 0; I < T.Factor; ++I)
 108       if (C.isZero())
 109         C = Counter::getCounter(T.CounterID);
 110       else
 111         C = get(CounterExpression(CounterExpression::Add, C,
 112                                   Counter::getCounter(T.CounterID)));
 113   }
 114
 115   // Create subtractions.
 116   for (auto T : Terms) {
 117     if (T.Factor >= 0)
 118       continue;
 119     for (int I = 0; I < -T.Factor; ++I)
 120       C = get(CounterExpression(CounterExpression::Subtract, C,
 121                                 Counter::getCounter(T.CounterID)));
 122   }
 123   return C;
 124 }
 125
 126 Counter CounterExpressionBuilder::add(Counter LHS, Counter RHS) {
 127   return simplify(get(CounterExpression(CounterExpression::Add, LHS, RHS)));
 128 }
 129
 130 Counter CounterExpressionBuilder::subtract(Counter LHS, Counter RHS) {
 131   return simplify(
 132       get(CounterExpression(CounterExpression::Subtract, LHS, RHS)));
 133 }
 134
 135 void CounterMappingContext::dump(const Counter &C, raw_ostream &OS) const {
 136   switch (C.getKind()) {
 137   case Counter::Zero:
 138     OS << '0';
 139     return;
 140   case Counter::CounterValueReference:
 141     OS << '#' << C.getCounterID();
 142     break;
 143   case Counter::Expression: {
 144     if (C.getExpressionID() >= Expressions.size())
 145       return;
 146     const auto &E = Expressions[C.getExpressionID()];
 147     OS << '(';
 148     dump(E.LHS, OS);
 149     OS << (E.Kind == CounterExpression::Subtract ? " - " : " + ");
 150     dump(E.RHS, OS);
 151     OS << ')';
 152     break;
 153   }
 154   }
 155   if (CounterValues.empty())
 156     return;
 157   Expected<int64_t> Value = evaluate(C);
 158   if (auto E = Value.takeError()) {
 159     consumeError(std::move(E));
 160     return;
 161   }
 162   OS << '[' << *Value << ']';
 163 }
 164
 165 Expected<int64_t> CounterMappingContext::evaluate(const Counter &C) const {
 166   switch (C.getKind()) {
 167   case Counter::Zero:
 168     return 0;
 169   case Counter::CounterValueReference:
 170     if (C.getCounterID() >= CounterValues.size())
 171       return errorCodeToError(errc::argument_out_of_domain);
 172     return CounterValues[C.getCounterID()];
 173   case Counter::Expression: {
 174     if (C.getExpressionID() >= Expressions.size())
 175       return errorCodeToError(errc::argument_out_of_domain);
 176     const auto &E = Expressions[C.getExpressionID()];
 177     Expected<int64_t> LHS = evaluate(E.LHS);
 178     if (!LHS)
 179       return LHS;
 180     Expected<int64_t> RHS = evaluate(E.RHS);
 181     if (!RHS)
 182       return RHS;
 183     return E.Kind == CounterExpression::Subtract ? *LHS - *RHS : *LHS + *RHS;
 184   }
 185   }
 186   llvm_unreachable("Unhandled CounterKind");
 187 }
 188
 189 void FunctionRecordIterator::skipOtherFiles() {
 190   while (Current != Records.end() && !Filename.empty() &&
 191          Filename != Current->Filenames[0])
 192     ++Current;
 193   if (Current == Records.end())
 194     *this = FunctionRecordIterator();
 195 }
 196
 197 ArrayRef<unsigned> CoverageMapping::getImpreciseRecordIndicesForFilename(
 198     StringRef Filename) const {
 199   size_t FilenameHash = hash_value(Filename);
 200   auto RecordIt = FilenameHash2RecordIndices.find(FilenameHash);
 201   if (RecordIt == FilenameHash2RecordIndices.end())
 202     return {};
 203   return RecordIt->second;
 204 }
 205
 206 Error CoverageMapping::loadFunctionRecord(
 207     const CoverageMappingRecord &Record,
 208     IndexedInstrProfReader &ProfileReader) {
 209   StringRef OrigFuncName = Record.FunctionName;
 210   if (OrigFuncName.empty())
 211     return make_error<CoverageMapError>(coveragemap_error::malformed);
 212
 213   if (Record.Filenames.empty())
 214     OrigFuncName = getFuncNameWithoutPrefix(OrigFuncName);
 215   else
 216     OrigFuncName = getFuncNameWithoutPrefix(OrigFuncName, Record.Filenames[0]);
 217
 218   CounterMappingContext Ctx(Record.Expressions);
 219
 220   std::vector<uint64_t> Counts;
 221   if (Error E = ProfileReader.getFunctionCounts(Record.FunctionName,
 222                                                 Record.FunctionHash, Counts)) {
 223     instrprof_error IPE = InstrProfError::take(std::move(E));
 224     if (IPE == instrprof_error::hash_mismatch) {
 225       FuncHashMismatches.emplace_back(Record.FunctionName, Record.FunctionHash);
 226       return Error::success();
 227     } else if (IPE != instrprof_error::unknown_function)
 228       return make_error<InstrProfError>(IPE);
 229     Counts.assign(Record.MappingRegions.size(), 0);
 230   }
 231   Ctx.setCounts(Counts);
 232
 233   assert(!Record.MappingRegions.empty() && "Function has no regions");
 234
 235   // This coverage record is a zero region for a function that's unused in
 236   // some TU, but used in a different TU. Ignore it. The coverage maps from the
 237   // the other TU will either be loaded (providing full region counts) or they
 238   // won't (in which case we don't unintuitively report functions as uncovered
 239   // when they have non-zero counts in the profile).
 240   if (Record.MappingRegions.size() == 1 &&
 241       Record.MappingRegions[0].Count.isZero() && Counts[0] > 0)
 242     return Error::success();
 243
 244   FunctionRecord Function(OrigFuncName, Record.Filenames);
 245   for (const auto &Region : Record.MappingRegions) {
 246     Expected<int64_t> ExecutionCount = Ctx.evaluate(Region.Count);
 247     if (auto E = ExecutionCount.takeError()) {
 248       consumeError(std::move(E));
 249       return Error::success();
 250     }
 251     Function.pushRegion(Region, *ExecutionCount);
 252   }
 253
 254   // Don't create records for (filenames, function) pairs we've already seen.
 255   auto FilenamesHash = hash_combine_range(Record.Filenames.begin(),
 256                                           Record.Filenames.end());
 257   if (!RecordProvenance[FilenamesHash].insert(hash_value(OrigFuncName)).second)
 258     return Error::success();
 259
 260   Functions.push_back(std::move(Function));
 261
 262   // Performance optimization: keep track of the indices of the function records
 263   // which correspond to each filename. This can be used to substantially speed
 264   // up queries for coverage info in a file.
 265   unsigned RecordIndex = Functions.size() - 1;
 266   for (StringRef Filename : Record.Filenames) {
 267     auto &RecordIndices = FilenameHash2RecordIndices[hash_value(Filename)];
 268     // Note that there may be duplicates in the filename set for a function
 269     // record, because of e.g. macro expansions in the function in which both
 270     // the macro and the function are defined in the same file.
 271     if (RecordIndices.empty() || RecordIndices.back() != RecordIndex)
 272       RecordIndices.push_back(RecordIndex);
 273   }
 274
 275   return Error::success();
 276 }
 277
 278 Expected<std::unique_ptr<CoverageMapping>> CoverageMapping::load(
 279     ArrayRef<std::unique_ptr<CoverageMappingReader>> CoverageReaders,
 280     IndexedInstrProfReader &ProfileReader) {
 281   auto Coverage = std::unique_ptr<CoverageMapping>(new CoverageMapping());
 282
 283   for (const auto &CoverageReader : CoverageReaders) {
 284     for (auto RecordOrErr : *CoverageReader) {
 285       if (Error E = RecordOrErr.takeError())
 286         return std::move(E);
 287       const auto &Record = *RecordOrErr;
 288       if (Error E = Coverage->loadFunctionRecord(Record, ProfileReader))
 289         return std::move(E);
 290     }
 291   }
 292
 293   return std::move(Coverage);
 294 }
 295
 296 // If E is a no_data_found error, returns success. Otherwise returns E.
 297 static Error handleMaybeNoDataFoundError(Error E) {
 298   return handleErrors(
 299       std::move(E), [](const CoverageMapError &CME) {
 300         if (CME.get() == coveragemap_error::no_data_found)
 301           return static_cast<Error>(Error::success());
 302         return make_error<CoverageMapError>(CME.get());
 303       });
 304 }
 305
 306 Expected<std::unique_ptr<CoverageMapping>>
 307 CoverageMapping::load(ArrayRef<StringRef> ObjectFilenames,
 308                       StringRef ProfileFilename, ArrayRef<StringRef> Arches) {
 309   auto ProfileReaderOrErr = IndexedInstrProfReader::create(ProfileFilename);
 310   if (Error E = ProfileReaderOrErr.takeError())
 311     return std::move(E);
 312   auto ProfileReader = std::move(ProfileReaderOrErr.get());
 313
 314   SmallVector<std::unique_ptr<CoverageMappingReader>, 4> Readers;
 315   SmallVector<std::unique_ptr<MemoryBuffer>, 4> Buffers;
 316   for (const auto &File : llvm::enumerate(ObjectFilenames)) {
 317     auto CovMappingBufOrErr = MemoryBuffer::getFileOrSTDIN(File.value());
 318     if (std::error_code EC = CovMappingBufOrErr.getError())
 319       return errorCodeToError(EC);
 320     StringRef Arch = Arches.empty() ? StringRef() : Arches[File.index()];
 321     MemoryBufferRef CovMappingBufRef =
 322         CovMappingBufOrErr.get()->getMemBufferRef();
 323     auto CoverageReadersOrErr =
 324         BinaryCoverageReader::create(CovMappingBufRef, Arch, Buffers);
 325     if (Error E = CoverageReadersOrErr.takeError()) {
 326       E = handleMaybeNoDataFoundError(std::move(E));
 327       if (E)
 328         return std::move(E);
 329       // E == success (originally a no_data_found error).
 330       continue;
 331     }
 332     for (auto &Reader : CoverageReadersOrErr.get())
 333       Readers.push_back(std::move(Reader));
 334     Buffers.push_back(std::move(CovMappingBufOrErr.get()));
 335   }
 336   // If no readers were created, either no objects were provided or none of them
 337   // had coverage data. Return an error in the latter case.
 338   if (Readers.empty() && !ObjectFilenames.empty())
 339     return make_error<CoverageMapError>(coveragemap_error::no_data_found);
 340   return load(Readers, *ProfileReader);
 341 }
 342
 343 namespace {
 344
 345 /// Distributes functions into instantiation sets.
 346 ///
 347 /// An instantiation set is a collection of functions that have the same source
 348 /// code, ie, template functions specializations.
 349 class FunctionInstantiationSetCollector {
 350   using MapT = std::map<LineColPair, std::vector<const FunctionRecord *>>;
 351   MapT InstantiatedFunctions;
 352
 353 public:
 354   void insert(const FunctionRecord &Function, unsigned FileID) {
 355     auto I = Function.CountedRegions.begin(), E = Function.CountedRegions.end();
 356     while (I != E && I->FileID != FileID)
 357       ++I;
 358     assert(I != E && "function does not cover the given file");
 359     auto &Functions = InstantiatedFunctions[I->startLoc()];
 360     Functions.push_back(&Function);
 361   }
 362
 363   MapT::iterator begin() { return InstantiatedFunctions.begin(); }
 364   MapT::iterator end() { return InstantiatedFunctions.end(); }
 365 };
 366
 367 class SegmentBuilder {
 368   std::vector<CoverageSegment> &Segments;
 369   SmallVector<const CountedRegion *, 8> ActiveRegions;
 370
 371   SegmentBuilder(std::vector<CoverageSegment> &Segments) : Segments(Segments) {}
 372
 373   /// Emit a segment with the count from \p Region starting at \p StartLoc.
 374   //
 375   /// \p IsRegionEntry: The segment is at the start of a new non-gap region.
 376   /// \p EmitSkippedRegion: The segment must be emitted as a skipped region.
 377   void startSegment(const CountedRegion &Region, LineColPair StartLoc,
 378                     bool IsRegionEntry, bool EmitSkippedRegion = false) {
 379     bool HasCount = !EmitSkippedRegion &&
 380                     (Region.Kind != CounterMappingRegion::SkippedRegion);
 381
 382     // If the new segment wouldn't affect coverage rendering, skip it.
 383     if (!Segments.empty() && !IsRegionEntry && !EmitSkippedRegion) {
 384       const auto &Last = Segments.back();
 385       if (Last.HasCount == HasCount && Last.Count == Region.ExecutionCount &&
 386           !Last.IsRegionEntry)
 387         return;
 388     }
 389
 390     if (HasCount)
 391       Segments.emplace_back(StartLoc.first, StartLoc.second,
 392                             Region.ExecutionCount, IsRegionEntry,
 393                             Region.Kind == CounterMappingRegion::GapRegion);
 394     else
 395       Segments.emplace_back(StartLoc.first, StartLoc.second, IsRegionEntry);
 396
 397     LLVM_DEBUG({
 398       const auto &Last = Segments.back();
 399       dbgs() << "Segment at " << Last.Line << ":" << Last.Col
 400              << " (count = " << Last.Count << ")"
 401              << (Last.IsRegionEntry ? ", RegionEntry" : "")
 402              << (!Last.HasCount ? ", Skipped" : "")
 403              << (Last.IsGapRegion ? ", Gap" : "") << "\n";
 404     });
 405   }
 406
 407   /// Emit segments for active regions which end before \p Loc.
 408   ///
 409   /// \p Loc: The start location of the next region. If None, all active
 410   /// regions are completed.
 411   /// \p FirstCompletedRegion: Index of the first completed region.
 412   void completeRegionsUntil(Optional<LineColPair> Loc,
 413                             unsigned FirstCompletedRegion) {
 414     // Sort the completed regions by end location. This makes it simple to
 415     // emit closing segments in sorted order.
 416     auto CompletedRegionsIt = ActiveRegions.begin() + FirstCompletedRegion;
 417     std::stable_sort(CompletedRegionsIt, ActiveRegions.end(),
 418                       [](const CountedRegion *L, const CountedRegion *R) {
 419                         return L->endLoc() < R->endLoc();
 420                       });
 421
 422     // Emit segments for all completed regions.
 423     for (unsigned I = FirstCompletedRegion + 1, E = ActiveRegions.size(); I < E;
 424          ++I) {
 425       const auto *CompletedRegion = ActiveRegions[I];
 426       assert((!Loc || CompletedRegion->endLoc() <= *Loc) &&
 427              "Completed region ends after start of new region");
 428
 429       const auto *PrevCompletedRegion = ActiveRegions[I - 1];
 430       auto CompletedSegmentLoc = PrevCompletedRegion->endLoc();
 431
 432       // Don't emit any more segments if they start where the new region begins.
 433       if (Loc && CompletedSegmentLoc == *Loc)
 434         break;
 435
 436       // Don't emit a segment if the next completed region ends at the same
 437       // location as this one.
 438       if (CompletedSegmentLoc == CompletedRegion->endLoc())
 439         continue;
 440
 441       // Use the count from the last completed region which ends at this loc.
 442       for (unsigned J = I + 1; J < E; ++J)
 443         if (CompletedRegion->endLoc() == ActiveRegions[J]->endLoc())
 444           CompletedRegion = ActiveRegions[J];
 445
 446       startSegment(*CompletedRegion, CompletedSegmentLoc, false);
 447     }
 448
 449     auto Last = ActiveRegions.back();
 450     if (FirstCompletedRegion && Last->endLoc() != *Loc) {
 451       // If there's a gap after the end of the last completed region and the
 452       // start of the new region, use the last active region to fill the gap.
 453       startSegment(*ActiveRegions[FirstCompletedRegion - 1], Last->endLoc(),
 454                    false);
 455     } else if (!FirstCompletedRegion && (!Loc || *Loc != Last->endLoc())) {
 456       // Emit a skipped segment if there are no more active regions. This
 457       // ensures that gaps between functions are marked correctly.
 458       startSegment(*Last, Last->endLoc(), false, true);
 459     }
 460
 461     // Pop the completed regions.
 462     ActiveRegions.erase(CompletedRegionsIt, ActiveRegions.end());
 463   }
 464
 465   void buildSegmentsImpl(ArrayRef<CountedRegion> Regions) {
 466     for (const auto &CR : enumerate(Regions)) {
 467       auto CurStartLoc = CR.value().startLoc();
 468
 469       // Active regions which end before the current region need to be popped.
 470       auto CompletedRegions =
 471           std::stable_partition(ActiveRegions.begin(), ActiveRegions.end(),
 472                                 [&](const CountedRegion *Region) {
 473                                   return !(Region->endLoc() <= CurStartLoc);
 474                                 });
 475       if (CompletedRegions != ActiveRegions.end()) {
 476         unsigned FirstCompletedRegion =
 477             std::distance(ActiveRegions.begin(), CompletedRegions);
 478         completeRegionsUntil(CurStartLoc, FirstCompletedRegion);
 479       }
 480
 481       bool GapRegion = CR.value().Kind == CounterMappingRegion::GapRegion;
 482
 483       // Try to emit a segment for the current region.
 484       if (CurStartLoc == CR.value().endLoc()) {
 485         // Avoid making zero-length regions active. If it's the last region,
 486         // emit a skipped segment. Otherwise use its predecessor's count.
 487         const bool Skipped = (CR.index() + 1) == Regions.size();
 488         startSegment(ActiveRegions.empty() ? CR.value() : *ActiveRegions.back(),
 489                      CurStartLoc, !GapRegion, Skipped);
 490         continue;
 491       }
 492       if (CR.index() + 1 == Regions.size() ||
 493           CurStartLoc != Regions[CR.index() + 1].startLoc()) {
 494         // Emit a segment if the next region doesn't start at the same location
 495         // as this one.
 496         startSegment(CR.value(), CurStartLoc, !GapRegion);
 497       }
 498
 499       // This region is active (i.e not completed).
 500       ActiveRegions.push_back(&CR.value());
 501     }
 502
 503     // Complete any remaining active regions.
 504     if (!ActiveRegions.empty())
 505       completeRegionsUntil(None, 0);
 506   }
 507
 508   /// Sort a nested sequence of regions from a single file.
 509   static void sortNestedRegions(MutableArrayRef<CountedRegion> Regions) {
 510     llvm::sort(Regions, [](const CountedRegion &LHS, const CountedRegion &RHS) {
 511       if (LHS.startLoc() != RHS.startLoc())
 512         return LHS.startLoc() < RHS.startLoc();
 513       if (LHS.endLoc() != RHS.endLoc())
 514         // When LHS completely contains RHS, we sort LHS first.
 515         return RHS.endLoc() < LHS.endLoc();
 516       // If LHS and RHS cover the same area, we need to sort them according
 517       // to their kinds so that the most suitable region will become "active"
 518       // in combineRegions(). Because we accumulate counter values only from
 519       // regions of the same kind as the first region of the area, prefer
 520       // CodeRegion to ExpansionRegion and ExpansionRegion to SkippedRegion.
 521       static_assert(CounterMappingRegion::CodeRegion <
 522                             CounterMappingRegion::ExpansionRegion &&
 523                         CounterMappingRegion::ExpansionRegion <
 524                             CounterMappingRegion::SkippedRegion,
 525                     "Unexpected order of region kind values");
 526       return LHS.Kind < RHS.Kind;
 527     });
 528   }
 529
 530   /// Combine counts of regions which cover the same area.
 531   static ArrayRef<CountedRegion>
 532   combineRegions(MutableArrayRef<CountedRegion> Regions) {
 533     if (Regions.empty())
 534       return Regions;
 535     auto Active = Regions.begin();
 536     auto End = Regions.end();
 537     for (auto I = Regions.begin() + 1; I != End; ++I) {
 538       if (Active->startLoc() != I->startLoc() ||
 539           Active->endLoc() != I->endLoc()) {
 540         // Shift to the next region.
 541         ++Active;
 542         if (Active != I)
 543           *Active = *I;
 544         continue;
 545       }
 546       // Merge duplicate region.
 547       // If CodeRegions and ExpansionRegions cover the same area, it's probably
 548       // a macro which is fully expanded to another macro. In that case, we need
 549       // to accumulate counts only from CodeRegions, or else the area will be
 550       // counted twice.
 551       // On the other hand, a macro may have a nested macro in its body. If the
 552       // outer macro is used several times, the ExpansionRegion for the nested
 553       // macro will also be added several times. These ExpansionRegions cover
 554       // the same source locations and have to be combined to reach the correct
 555       // value for that area.
 556       // We add counts of the regions of the same kind as the active region
 557       // to handle the both situations.
 558       if (I->Kind == Active->Kind)
 559         Active->ExecutionCount += I->ExecutionCount;
 560     }
 561     return Regions.drop_back(std::distance(++Active, End));
 562   }
 563
 564 public:
 565   /// Build a sorted list of CoverageSegments from a list of Regions.
 566   static std::vector<CoverageSegment>
 567   buildSegments(MutableArrayRef<CountedRegion> Regions) {
 568     std::vector<CoverageSegment> Segments;
 569     SegmentBuilder Builder(Segments);
 570
 571     sortNestedRegions(Regions);
 572     ArrayRef<CountedRegion> CombinedRegions = combineRegions(Regions);
 573
 574     LLVM_DEBUG({
 575       dbgs() << "Combined regions:\n";
 576       for (const auto &CR : CombinedRegions)
 577         dbgs() << "  " << CR.LineStart << ":" << CR.ColumnStart << " -> "
 578                << CR.LineEnd << ":" << CR.ColumnEnd
 579                << " (count=" << CR.ExecutionCount << ")\n";
 580     });
 581
 582     Builder.buildSegmentsImpl(CombinedRegions);
 583
 584 #ifndef NDEBUG
 585     for (unsigned I = 1, E = Segments.size(); I < E; ++I) {
 586       const auto &L = Segments[I - 1];
 587       const auto &R = Segments[I];
 588       if (!(L.Line < R.Line) && !(L.Line == R.Line && L.Col < R.Col)) {
 589         LLVM_DEBUG(dbgs() << " ! Segment " << L.Line << ":" << L.Col
 590                           << " followed by " << R.Line << ":" << R.Col << "\n");
 591         assert(false && "Coverage segments not unique or sorted");
 592       }
 593     }
 594 #endif
 595
 596     return Segments;
 597   }
 598 };
 599
 600 } // end anonymous namespace
 601
 602 std::vector<StringRef> CoverageMapping::getUniqueSourceFiles() const {
 603   std::vector<StringRef> Filenames;
 604   for (const auto &Function : getCoveredFunctions())
 605     Filenames.insert(Filenames.end(), Function.Filenames.begin(),
 606                      Function.Filenames.end());
 607   llvm::sort(Filenames);
 608   auto Last = std::unique(Filenames.begin(), Filenames.end());
 609   Filenames.erase(Last, Filenames.end());
 610   return Filenames;
 611 }
 612
 613 static SmallBitVector gatherFileIDs(StringRef SourceFile,
 614                                     const FunctionRecord &Function) {
 615   SmallBitVector FilenameEquivalence(Function.Filenames.size(), false);
 616   for (unsigned I = 0, E = Function.Filenames.size(); I < E; ++I)
 617     if (SourceFile == Function.Filenames[I])
 618       FilenameEquivalence[I] = true;
 619   return FilenameEquivalence;
 620 }
 621
 622 /// Return the ID of the file where the definition of the function is located.
 623 static Optional<unsigned> findMainViewFileID(const FunctionRecord &Function) {
 624   SmallBitVector IsNotExpandedFile(Function.Filenames.size(), true);
 625   for (const auto &CR : Function.CountedRegions)
 626     if (CR.Kind == CounterMappingRegion::ExpansionRegion)
 627       IsNotExpandedFile[CR.ExpandedFileID] = false;
 628   int I = IsNotExpandedFile.find_first();
 629   if (I == -1)
 630     return None;
 631   return I;
 632 }
 633
 634 /// Check if SourceFile is the file that contains the definition of
 635 /// the Function. Return the ID of the file in that case or None otherwise.
 636 static Optional<unsigned> findMainViewFileID(StringRef SourceFile,
 637                                              const FunctionRecord &Function) {
 638   Optional<unsigned> I = findMainViewFileID(Function);
 639   if (I && SourceFile == Function.Filenames[*I])
 640     return I;
 641   return None;
 642 }
 643
 644 static bool isExpansion(const CountedRegion &R, unsigned FileID) {
 645   return R.Kind == CounterMappingRegion::ExpansionRegion && R.FileID == FileID;
 646 }
 647
 648 CoverageData CoverageMapping::getCoverageForFile(StringRef Filename) const {
 649   CoverageData FileCoverage(Filename);
 650   std::vector<CountedRegion> Regions;
 651
 652   // Look up the function records in the given file. Due to hash collisions on
 653   // the filename, we may get back some records that are not in the file.
 654   ArrayRef<unsigned> RecordIndices =
 655       getImpreciseRecordIndicesForFilename(Filename);
 656   for (unsigned RecordIndex : RecordIndices) {
 657     const FunctionRecord &Function = Functions[RecordIndex];
 658     auto MainFileID = findMainViewFileID(Filename, Function);
 659     auto FileIDs = gatherFileIDs(Filename, Function);
 660     for (const auto &CR : Function.CountedRegions)
 661       if (FileIDs.test(CR.FileID)) {
 662         Regions.push_back(CR);
 663         if (MainFileID && isExpansion(CR, *MainFileID))
 664           FileCoverage.Expansions.emplace_back(CR, Function);
 665       }
 666   }
 667
 668   LLVM_DEBUG(dbgs() << "Emitting segments for file: " << Filename << "\n");
 669   FileCoverage.Segments = SegmentBuilder::buildSegments(Regions);
 670
 671   return FileCoverage;
 672 }
 673
 674 std::vector<InstantiationGroup>
 675 CoverageMapping::getInstantiationGroups(StringRef Filename) const {
 676   FunctionInstantiationSetCollector InstantiationSetCollector;
 677   // Look up the function records in the given file. Due to hash collisions on
 678   // the filename, we may get back some records that are not in the file.
 679   ArrayRef<unsigned> RecordIndices =
 680       getImpreciseRecordIndicesForFilename(Filename);
 681   for (unsigned RecordIndex : RecordIndices) {
 682     const FunctionRecord &Function = Functions[RecordIndex];
 683     auto MainFileID = findMainViewFileID(Filename, Function);
 684     if (!MainFileID)
 685       continue;
 686     InstantiationSetCollector.insert(Function, *MainFileID);
 687   }
 688
 689   std::vector<InstantiationGroup> Result;
 690   for (auto &InstantiationSet : InstantiationSetCollector) {
 691     InstantiationGroup IG{InstantiationSet.first.first,
 692                           InstantiationSet.first.second,
 693                           std::move(InstantiationSet.second)};
 694     Result.emplace_back(std::move(IG));
 695   }
 696   return Result;
 697 }
 698
 699 CoverageData
 700 CoverageMapping::getCoverageForFunction(const FunctionRecord &Function) const {
 701   auto MainFileID = findMainViewFileID(Function);
 702   if (!MainFileID)
 703     return CoverageData();
 704
 705   CoverageData FunctionCoverage(Function.Filenames[*MainFileID]);
 706   std::vector<CountedRegion> Regions;
 707   for (const auto &CR : Function.CountedRegions)
 708     if (CR.FileID == *MainFileID) {
 709       Regions.push_back(CR);
 710       if (isExpansion(CR, *MainFileID))
 711         FunctionCoverage.Expansions.emplace_back(CR, Function);
 712     }
 713
 714   LLVM_DEBUG(dbgs() << "Emitting segments for function: " << Function.Name
 715                     << "\n");
 716   FunctionCoverage.Segments = SegmentBuilder::buildSegments(Regions);
 717
 718   return FunctionCoverage;
 719 }
 720
 721 CoverageData CoverageMapping::getCoverageForExpansion(
 722     const ExpansionRecord &Expansion) const {
 723   CoverageData ExpansionCoverage(
 724       Expansion.Function.Filenames[Expansion.FileID]);
 725   std::vector<CountedRegion> Regions;
 726   for (const auto &CR : Expansion.Function.CountedRegions)
 727     if (CR.FileID == Expansion.FileID) {
 728       Regions.push_back(CR);
 729       if (isExpansion(CR, Expansion.FileID))
 730         ExpansionCoverage.Expansions.emplace_back(CR, Expansion.Function);
 731     }
 732
 733   LLVM_DEBUG(dbgs() << "Emitting segments for expansion of file "
 734                     << Expansion.FileID << "\n");
 735   ExpansionCoverage.Segments = SegmentBuilder::buildSegments(Regions);
 736
 737   return ExpansionCoverage;
 738 }
 739
 740 LineCoverageStats::LineCoverageStats(
 741     ArrayRef<const CoverageSegment *> LineSegments,
 742     const CoverageSegment *WrappedSegment, unsigned Line)
 743     : ExecutionCount(0), HasMultipleRegions(false), Mapped(false), Line(Line),
 744       LineSegments(LineSegments), WrappedSegment(WrappedSegment) {
 745   // Find the minimum number of regions which start in this line.
 746   unsigned MinRegionCount = 0;
 747   auto isStartOfRegion = [](const CoverageSegment *S) {
 748     return !S->IsGapRegion && S->HasCount && S->IsRegionEntry;
 749   };
 750   for (unsigned I = 0; I < LineSegments.size() && MinRegionCount < 2; ++I)
 751     if (isStartOfRegion(LineSegments[I]))
 752       ++MinRegionCount;
 753
 754   bool StartOfSkippedRegion = !LineSegments.empty() &&
 755                               !LineSegments.front()->HasCount &&
 756                               LineSegments.front()->IsRegionEntry;
 757
 758   HasMultipleRegions = MinRegionCount > 1;
 759   Mapped =
 760       !StartOfSkippedRegion &&
 761       ((WrappedSegment && WrappedSegment->HasCount) || (MinRegionCount > 0));
 762
 763   if (!Mapped)
 764     return;
 765
 766   // Pick the max count from the non-gap, region entry segments and the
 767   // wrapped count.
 768   if (WrappedSegment)
 769     ExecutionCount = WrappedSegment->Count;
 770   if (!MinRegionCount)
 771     return;
 772   for (const auto *LS : LineSegments)
 773     if (isStartOfRegion(LS))
 774       ExecutionCount = std::max(ExecutionCount, LS->Count);
 775 }
 776
 777 LineCoverageIterator &LineCoverageIterator::operator++() {
 778   if (Next == CD.end()) {
 779     Stats = LineCoverageStats();
 780     Ended = true;
 781     return *this;
 782   }
 783   if (Segments.size())
 784     WrappedSegment = Segments.back();
 785   Segments.clear();
 786   while (Next != CD.end() && Next->Line == Line)
 787     Segments.push_back(&*Next++);
 788   Stats = LineCoverageStats(Segments, WrappedSegment, Line);
 789   ++Line;
 790   return *this;
 791 }
 792
 793 static std::string getCoverageMapErrString(coveragemap_error Err) {
 794   switch (Err) {
 795   case coveragemap_error::success:
 796     return "Success";
 797   case coveragemap_error::eof:
 798     return "End of File";
 799   case coveragemap_error::no_data_found:
 800     return "No coverage data found";
 801   case coveragemap_error::unsupported_version:
 802     return "Unsupported coverage format version";
 803   case coveragemap_error::truncated:
 804     return "Truncated coverage data";
 805   case coveragemap_error::malformed:
 806     return "Malformed coverage data";
 807   }
 808   llvm_unreachable("A value of coveragemap_error has no message.");
 809 }
 810
 811 namespace {
 812
 813 // FIXME: This class is only here to support the transition to llvm::Error. It
 814 // will be removed once this transition is complete. Clients should prefer to
 815 // deal with the Error value directly, rather than converting to error_code.
 816 class CoverageMappingErrorCategoryType : public std::error_category {
 817   const char *name() const noexcept override { return "llvm.coveragemap"; }
 818   std::string message(int IE) const override {
 819     return getCoverageMapErrString(static_cast<coveragemap_error>(IE));
 820   }
 821 };
 822
 823 } // end anonymous namespace
 824
 825 std::string CoverageMapError::message() const {
 826   return getCoverageMapErrString(Err);
 827 }
 828
 829 static ManagedStatic<CoverageMappingErrorCategoryType> ErrorCategory;
 830
 831 const std::error_category &llvm::coverage::coveragemap_category() {
 832   return *ErrorCategory;
 833 }
 834
 835 char CoverageMapError::ID = 0;