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 Error CoverageMapping::loadFunctionRecord(
 198     const CoverageMappingRecord &Record,
 199     IndexedInstrProfReader &ProfileReader) {
 200   StringRef OrigFuncName = Record.FunctionName;
 201   if (OrigFuncName.empty())
 202     return make_error<CoverageMapError>(coveragemap_error::malformed);
 203
 204   if (Record.Filenames.empty())
 205     OrigFuncName = getFuncNameWithoutPrefix(OrigFuncName);
 206   else
 207     OrigFuncName = getFuncNameWithoutPrefix(OrigFuncName, Record.Filenames[0]);
 208
 209   CounterMappingContext Ctx(Record.Expressions);
 210
 211   std::vector<uint64_t> Counts;
 212   if (Error E = ProfileReader.getFunctionCounts(Record.FunctionName,
 213                                                 Record.FunctionHash, Counts)) {
 214     instrprof_error IPE = InstrProfError::take(std::move(E));
 215     if (IPE == instrprof_error::hash_mismatch) {
 216       FuncHashMismatches.emplace_back(Record.FunctionName, Record.FunctionHash);
 217       return Error::success();
 218     } else if (IPE != instrprof_error::unknown_function)
 219       return make_error<InstrProfError>(IPE);
 220     Counts.assign(Record.MappingRegions.size(), 0);
 221   }
 222   Ctx.setCounts(Counts);
 223
 224   assert(!Record.MappingRegions.empty() && "Function has no regions");
 225
 226   // This coverage record is a zero region for a function that's unused in
 227   // some TU, but used in a different TU. Ignore it. The coverage maps from the
 228   // the other TU will either be loaded (providing full region counts) or they
 229   // won't (in which case we don't unintuitively report functions as uncovered
 230   // when they have non-zero counts in the profile).
 231   if (Record.MappingRegions.size() == 1 &&
 232       Record.MappingRegions[0].Count.isZero() && Counts[0] > 0)
 233     return Error::success();
 234
 235   FunctionRecord Function(OrigFuncName, Record.Filenames);
 236   for (const auto &Region : Record.MappingRegions) {
 237     Expected<int64_t> ExecutionCount = Ctx.evaluate(Region.Count);
 238     if (auto E = ExecutionCount.takeError()) {
 239       consumeError(std::move(E));
 240       return Error::success();
 241     }
 242     Function.pushRegion(Region, *ExecutionCount);
 243   }
 244
 245   // Don't create records for (filenames, function) pairs we've already seen.
 246   auto FilenamesHash = hash_combine_range(Record.Filenames.begin(),
 247                                           Record.Filenames.end());
 248   if (!RecordProvenance[FilenamesHash].insert(hash_value(OrigFuncName)).second)
 249     return Error::success();
 250
 251   Functions.push_back(std::move(Function));
 252   return Error::success();
 253 }
 254
 255 Expected<std::unique_ptr<CoverageMapping>> CoverageMapping::load(
 256     ArrayRef<std::unique_ptr<CoverageMappingReader>> CoverageReaders,
 257     IndexedInstrProfReader &ProfileReader) {
 258   auto Coverage = std::unique_ptr<CoverageMapping>(new CoverageMapping());
 259
 260   for (const auto &CoverageReader : CoverageReaders) {
 261     for (auto RecordOrErr : *CoverageReader) {
 262       if (Error E = RecordOrErr.takeError())
 263         return std::move(E);
 264       const auto &Record = *RecordOrErr;
 265       if (Error E = Coverage->loadFunctionRecord(Record, ProfileReader))
 266         return std::move(E);
 267     }
 268   }
 269
 270   return std::move(Coverage);
 271 }
 272
 273 // If E is a no_data_found error, returns success. Otherwise returns E.
 274 static Error handleMaybeNoDataFoundError(Error E) {
 275   return handleErrors(
 276       std::move(E), [](const CoverageMapError &CME) {
 277         if (CME.get() == coveragemap_error::no_data_found)
 278           return static_cast<Error>(Error::success());
 279         return make_error<CoverageMapError>(CME.get());
 280       });
 281 }
 282
 283 Expected<std::unique_ptr<CoverageMapping>>
 284 CoverageMapping::load(ArrayRef<StringRef> ObjectFilenames,
 285                       StringRef ProfileFilename, ArrayRef<StringRef> Arches) {
 286   auto ProfileReaderOrErr = IndexedInstrProfReader::create(ProfileFilename);
 287   if (Error E = ProfileReaderOrErr.takeError())
 288     return std::move(E);
 289   auto ProfileReader = std::move(ProfileReaderOrErr.get());
 290
 291   SmallVector<std::unique_ptr<CoverageMappingReader>, 4> Readers;
 292   SmallVector<std::unique_ptr<MemoryBuffer>, 4> Buffers;
 293   for (const auto &File : llvm::enumerate(ObjectFilenames)) {
 294     auto CovMappingBufOrErr = MemoryBuffer::getFileOrSTDIN(File.value());
 295     if (std::error_code EC = CovMappingBufOrErr.getError())
 296       return errorCodeToError(EC);
 297     StringRef Arch = Arches.empty() ? StringRef() : Arches[File.index()];
 298     MemoryBufferRef CovMappingBufRef =
 299         CovMappingBufOrErr.get()->getMemBufferRef();
 300     auto CoverageReadersOrErr =
 301         BinaryCoverageReader::create(CovMappingBufRef, Arch, Buffers);
 302     if (Error E = CoverageReadersOrErr.takeError()) {
 303       E = handleMaybeNoDataFoundError(std::move(E));
 304       if (E)
 305         return std::move(E);
 306       // E == success (originally a no_data_found error).
 307       continue;
 308     }
 309     for (auto &Reader : CoverageReadersOrErr.get())
 310       Readers.push_back(std::move(Reader));
 311     Buffers.push_back(std::move(CovMappingBufOrErr.get()));
 312   }
 313   // If no readers were created, either no objects were provided or none of them
 314   // had coverage data. Return an error in the latter case.
 315   if (Readers.empty() && !ObjectFilenames.empty())
 316     return make_error<CoverageMapError>(coveragemap_error::no_data_found);
 317   return load(Readers, *ProfileReader);
 318 }
 319
 320 namespace {
 321
 322 /// Distributes functions into instantiation sets.
 323 ///
 324 /// An instantiation set is a collection of functions that have the same source
 325 /// code, ie, template functions specializations.
 326 class FunctionInstantiationSetCollector {
 327   using MapT = std::map<LineColPair, std::vector<const FunctionRecord *>>;
 328   MapT InstantiatedFunctions;
 329
 330 public:
 331   void insert(const FunctionRecord &Function, unsigned FileID) {
 332     auto I = Function.CountedRegions.begin(), E = Function.CountedRegions.end();
 333     while (I != E && I->FileID != FileID)
 334       ++I;
 335     assert(I != E && "function does not cover the given file");
 336     auto &Functions = InstantiatedFunctions[I->startLoc()];
 337     Functions.push_back(&Function);
 338   }
 339
 340   MapT::iterator begin() { return InstantiatedFunctions.begin(); }
 341   MapT::iterator end() { return InstantiatedFunctions.end(); }
 342 };
 343
 344 class SegmentBuilder {
 345   std::vector<CoverageSegment> &Segments;
 346   SmallVector<const CountedRegion *, 8> ActiveRegions;
 347
 348   SegmentBuilder(std::vector<CoverageSegment> &Segments) : Segments(Segments) {}
 349
 350   /// Emit a segment with the count from \p Region starting at \p StartLoc.
 351   //
 352   /// \p IsRegionEntry: The segment is at the start of a new non-gap region.
 353   /// \p EmitSkippedRegion: The segment must be emitted as a skipped region.
 354   void startSegment(const CountedRegion &Region, LineColPair StartLoc,
 355                     bool IsRegionEntry, bool EmitSkippedRegion = false) {
 356     bool HasCount = !EmitSkippedRegion &&
 357                     (Region.Kind != CounterMappingRegion::SkippedRegion);
 358
 359     // If the new segment wouldn't affect coverage rendering, skip it.
 360     if (!Segments.empty() && !IsRegionEntry && !EmitSkippedRegion) {
 361       const auto &Last = Segments.back();
 362       if (Last.HasCount == HasCount && Last.Count == Region.ExecutionCount &&
 363           !Last.IsRegionEntry)
 364         return;
 365     }
 366
 367     if (HasCount)
 368       Segments.emplace_back(StartLoc.first, StartLoc.second,
 369                             Region.ExecutionCount, IsRegionEntry,
 370                             Region.Kind == CounterMappingRegion::GapRegion);
 371     else
 372       Segments.emplace_back(StartLoc.first, StartLoc.second, IsRegionEntry);
 373
 374     LLVM_DEBUG({
 375       const auto &Last = Segments.back();
 376       dbgs() << "Segment at " << Last.Line << ":" << Last.Col
 377              << " (count = " << Last.Count << ")"
 378              << (Last.IsRegionEntry ? ", RegionEntry" : "")
 379              << (!Last.HasCount ? ", Skipped" : "")
 380              << (Last.IsGapRegion ? ", Gap" : "") << "\n";
 381     });
 382   }
 383
 384   /// Emit segments for active regions which end before \p Loc.
 385   ///
 386   /// \p Loc: The start location of the next region. If None, all active
 387   /// regions are completed.
 388   /// \p FirstCompletedRegion: Index of the first completed region.
 389   void completeRegionsUntil(Optional<LineColPair> Loc,
 390                             unsigned FirstCompletedRegion) {
 391     // Sort the completed regions by end location. This makes it simple to
 392     // emit closing segments in sorted order.
 393     auto CompletedRegionsIt = ActiveRegions.begin() + FirstCompletedRegion;
 394     std::stable_sort(CompletedRegionsIt, ActiveRegions.end(),
 395                       [](const CountedRegion *L, const CountedRegion *R) {
 396                         return L->endLoc() < R->endLoc();
 397                       });
 398
 399     // Emit segments for all completed regions.
 400     for (unsigned I = FirstCompletedRegion + 1, E = ActiveRegions.size(); I < E;
 401          ++I) {
 402       const auto *CompletedRegion = ActiveRegions[I];
 403       assert((!Loc || CompletedRegion->endLoc() <= *Loc) &&
 404              "Completed region ends after start of new region");
 405
 406       const auto *PrevCompletedRegion = ActiveRegions[I - 1];
 407       auto CompletedSegmentLoc = PrevCompletedRegion->endLoc();
 408
 409       // Don't emit any more segments if they start where the new region begins.
 410       if (Loc && CompletedSegmentLoc == *Loc)
 411         break;
 412
 413       // Don't emit a segment if the next completed region ends at the same
 414       // location as this one.
 415       if (CompletedSegmentLoc == CompletedRegion->endLoc())
 416         continue;
 417
 418       // Use the count from the last completed region which ends at this loc.
 419       for (unsigned J = I + 1; J < E; ++J)
 420         if (CompletedRegion->endLoc() == ActiveRegions[J]->endLoc())
 421           CompletedRegion = ActiveRegions[J];
 422
 423       startSegment(*CompletedRegion, CompletedSegmentLoc, false);
 424     }
 425
 426     auto Last = ActiveRegions.back();
 427     if (FirstCompletedRegion && Last->endLoc() != *Loc) {
 428       // If there's a gap after the end of the last completed region and the
 429       // start of the new region, use the last active region to fill the gap.
 430       startSegment(*ActiveRegions[FirstCompletedRegion - 1], Last->endLoc(),
 431                    false);
 432     } else if (!FirstCompletedRegion && (!Loc || *Loc != Last->endLoc())) {
 433       // Emit a skipped segment if there are no more active regions. This
 434       // ensures that gaps between functions are marked correctly.
 435       startSegment(*Last, Last->endLoc(), false, true);
 436     }
 437
 438     // Pop the completed regions.
 439     ActiveRegions.erase(CompletedRegionsIt, ActiveRegions.end());
 440   }
 441
 442   void buildSegmentsImpl(ArrayRef<CountedRegion> Regions) {
 443     for (const auto &CR : enumerate(Regions)) {
 444       auto CurStartLoc = CR.value().startLoc();
 445
 446       // Active regions which end before the current region need to be popped.
 447       auto CompletedRegions =
 448           std::stable_partition(ActiveRegions.begin(), ActiveRegions.end(),
 449                                 [&](const CountedRegion *Region) {
 450                                   return !(Region->endLoc() <= CurStartLoc);
 451                                 });
 452       if (CompletedRegions != ActiveRegions.end()) {
 453         unsigned FirstCompletedRegion =
 454             std::distance(ActiveRegions.begin(), CompletedRegions);
 455         completeRegionsUntil(CurStartLoc, FirstCompletedRegion);
 456       }
 457
 458       bool GapRegion = CR.value().Kind == CounterMappingRegion::GapRegion;
 459
 460       // Try to emit a segment for the current region.
 461       if (CurStartLoc == CR.value().endLoc()) {
 462         // Avoid making zero-length regions active. If it's the last region,
 463         // emit a skipped segment. Otherwise use its predecessor's count.
 464         const bool Skipped = (CR.index() + 1) == Regions.size();
 465         startSegment(ActiveRegions.empty() ? CR.value() : *ActiveRegions.back(),
 466                      CurStartLoc, !GapRegion, Skipped);
 467         continue;
 468       }
 469       if (CR.index() + 1 == Regions.size() ||
 470           CurStartLoc != Regions[CR.index() + 1].startLoc()) {
 471         // Emit a segment if the next region doesn't start at the same location
 472         // as this one.
 473         startSegment(CR.value(), CurStartLoc, !GapRegion);
 474       }
 475
 476       // This region is active (i.e not completed).
 477       ActiveRegions.push_back(&CR.value());
 478     }
 479
 480     // Complete any remaining active regions.
 481     if (!ActiveRegions.empty())
 482       completeRegionsUntil(None, 0);
 483   }
 484
 485   /// Sort a nested sequence of regions from a single file.
 486   static void sortNestedRegions(MutableArrayRef<CountedRegion> Regions) {
 487     llvm::sort(Regions, [](const CountedRegion &LHS, const CountedRegion &RHS) {
 488       if (LHS.startLoc() != RHS.startLoc())
 489         return LHS.startLoc() < RHS.startLoc();
 490       if (LHS.endLoc() != RHS.endLoc())
 491         // When LHS completely contains RHS, we sort LHS first.
 492         return RHS.endLoc() < LHS.endLoc();
 493       // If LHS and RHS cover the same area, we need to sort them according
 494       // to their kinds so that the most suitable region will become "active"
 495       // in combineRegions(). Because we accumulate counter values only from
 496       // regions of the same kind as the first region of the area, prefer
 497       // CodeRegion to ExpansionRegion and ExpansionRegion to SkippedRegion.
 498       static_assert(CounterMappingRegion::CodeRegion <
 499                             CounterMappingRegion::ExpansionRegion &&
 500                         CounterMappingRegion::ExpansionRegion <
 501                             CounterMappingRegion::SkippedRegion,
 502                     "Unexpected order of region kind values");
 503       return LHS.Kind < RHS.Kind;
 504     });
 505   }
 506
 507   /// Combine counts of regions which cover the same area.
 508   static ArrayRef<CountedRegion>
 509   combineRegions(MutableArrayRef<CountedRegion> Regions) {
 510     if (Regions.empty())
 511       return Regions;
 512     auto Active = Regions.begin();
 513     auto End = Regions.end();
 514     for (auto I = Regions.begin() + 1; I != End; ++I) {
 515       if (Active->startLoc() != I->startLoc() ||
 516           Active->endLoc() != I->endLoc()) {
 517         // Shift to the next region.
 518         ++Active;
 519         if (Active != I)
 520           *Active = *I;
 521         continue;
 522       }
 523       // Merge duplicate region.
 524       // If CodeRegions and ExpansionRegions cover the same area, it's probably
 525       // a macro which is fully expanded to another macro. In that case, we need
 526       // to accumulate counts only from CodeRegions, or else the area will be
 527       // counted twice.
 528       // On the other hand, a macro may have a nested macro in its body. If the
 529       // outer macro is used several times, the ExpansionRegion for the nested
 530       // macro will also be added several times. These ExpansionRegions cover
 531       // the same source locations and have to be combined to reach the correct
 532       // value for that area.
 533       // We add counts of the regions of the same kind as the active region
 534       // to handle the both situations.
 535       if (I->Kind == Active->Kind)
 536         Active->ExecutionCount += I->ExecutionCount;
 537     }
 538     return Regions.drop_back(std::distance(++Active, End));
 539   }
 540
 541 public:
 542   /// Build a sorted list of CoverageSegments from a list of Regions.
 543   static std::vector<CoverageSegment>
 544   buildSegments(MutableArrayRef<CountedRegion> Regions) {
 545     std::vector<CoverageSegment> Segments;
 546     SegmentBuilder Builder(Segments);
 547
 548     sortNestedRegions(Regions);
 549     ArrayRef<CountedRegion> CombinedRegions = combineRegions(Regions);
 550
 551     LLVM_DEBUG({
 552       dbgs() << "Combined regions:\n";
 553       for (const auto &CR : CombinedRegions)
 554         dbgs() << "  " << CR.LineStart << ":" << CR.ColumnStart << " -> "
 555                << CR.LineEnd << ":" << CR.ColumnEnd
 556                << " (count=" << CR.ExecutionCount << ")\n";
 557     });
 558
 559     Builder.buildSegmentsImpl(CombinedRegions);
 560
 561 #ifndef NDEBUG
 562     for (unsigned I = 1, E = Segments.size(); I < E; ++I) {
 563       const auto &L = Segments[I - 1];
 564       const auto &R = Segments[I];
 565       if (!(L.Line < R.Line) && !(L.Line == R.Line && L.Col < R.Col)) {
 566         LLVM_DEBUG(dbgs() << " ! Segment " << L.Line << ":" << L.Col
 567                           << " followed by " << R.Line << ":" << R.Col << "\n");
 568         assert(false && "Coverage segments not unique or sorted");
 569       }
 570     }
 571 #endif
 572
 573     return Segments;
 574   }
 575 };
 576
 577 } // end anonymous namespace
 578
 579 std::vector<StringRef> CoverageMapping::getUniqueSourceFiles() const {
 580   std::vector<StringRef> Filenames;
 581   for (const auto &Function : getCoveredFunctions())
 582     Filenames.insert(Filenames.end(), Function.Filenames.begin(),
 583                      Function.Filenames.end());
 584   llvm::sort(Filenames);
 585   auto Last = std::unique(Filenames.begin(), Filenames.end());
 586   Filenames.erase(Last, Filenames.end());
 587   return Filenames;
 588 }
 589
 590 static SmallBitVector gatherFileIDs(StringRef SourceFile,
 591                                     const FunctionRecord &Function) {
 592   SmallBitVector FilenameEquivalence(Function.Filenames.size(), false);
 593   for (unsigned I = 0, E = Function.Filenames.size(); I < E; ++I)
 594     if (SourceFile == Function.Filenames[I])
 595       FilenameEquivalence[I] = true;
 596   return FilenameEquivalence;
 597 }
 598
 599 /// Return the ID of the file where the definition of the function is located.
 600 static Optional<unsigned> findMainViewFileID(const FunctionRecord &Function) {
 601   SmallBitVector IsNotExpandedFile(Function.Filenames.size(), true);
 602   for (const auto &CR : Function.CountedRegions)
 603     if (CR.Kind == CounterMappingRegion::ExpansionRegion)
 604       IsNotExpandedFile[CR.ExpandedFileID] = false;
 605   int I = IsNotExpandedFile.find_first();
 606   if (I == -1)
 607     return None;
 608   return I;
 609 }
 610
 611 /// Check if SourceFile is the file that contains the definition of
 612 /// the Function. Return the ID of the file in that case or None otherwise.
 613 static Optional<unsigned> findMainViewFileID(StringRef SourceFile,
 614                                              const FunctionRecord &Function) {
 615   Optional<unsigned> I = findMainViewFileID(Function);
 616   if (I && SourceFile == Function.Filenames[*I])
 617     return I;
 618   return None;
 619 }
 620
 621 static bool isExpansion(const CountedRegion &R, unsigned FileID) {
 622   return R.Kind == CounterMappingRegion::ExpansionRegion && R.FileID == FileID;
 623 }
 624
 625 CoverageData CoverageMapping::getCoverageForFile(StringRef Filename) const {
 626   CoverageData FileCoverage(Filename);
 627   std::vector<CountedRegion> Regions;
 628
 629   for (const auto &Function : Functions) {
 630     auto MainFileID = findMainViewFileID(Filename, Function);
 631     auto FileIDs = gatherFileIDs(Filename, Function);
 632     for (const auto &CR : Function.CountedRegions)
 633       if (FileIDs.test(CR.FileID)) {
 634         Regions.push_back(CR);
 635         if (MainFileID && isExpansion(CR, *MainFileID))
 636           FileCoverage.Expansions.emplace_back(CR, Function);
 637       }
 638   }
 639
 640   LLVM_DEBUG(dbgs() << "Emitting segments for file: " << Filename << "\n");
 641   FileCoverage.Segments = SegmentBuilder::buildSegments(Regions);
 642
 643   return FileCoverage;
 644 }
 645
 646 std::vector<InstantiationGroup>
 647 CoverageMapping::getInstantiationGroups(StringRef Filename) const {
 648   FunctionInstantiationSetCollector InstantiationSetCollector;
 649   for (const auto &Function : Functions) {
 650     auto MainFileID = findMainViewFileID(Filename, Function);
 651     if (!MainFileID)
 652       continue;
 653     InstantiationSetCollector.insert(Function, *MainFileID);
 654   }
 655
 656   std::vector<InstantiationGroup> Result;
 657   for (auto &InstantiationSet : InstantiationSetCollector) {
 658     InstantiationGroup IG{InstantiationSet.first.first,
 659                           InstantiationSet.first.second,
 660                           std::move(InstantiationSet.second)};
 661     Result.emplace_back(std::move(IG));
 662   }
 663   return Result;
 664 }
 665
 666 CoverageData
 667 CoverageMapping::getCoverageForFunction(const FunctionRecord &Function) const {
 668   auto MainFileID = findMainViewFileID(Function);
 669   if (!MainFileID)
 670     return CoverageData();
 671
 672   CoverageData FunctionCoverage(Function.Filenames[*MainFileID]);
 673   std::vector<CountedRegion> Regions;
 674   for (const auto &CR : Function.CountedRegions)
 675     if (CR.FileID == *MainFileID) {
 676       Regions.push_back(CR);
 677       if (isExpansion(CR, *MainFileID))
 678         FunctionCoverage.Expansions.emplace_back(CR, Function);
 679     }
 680
 681   LLVM_DEBUG(dbgs() << "Emitting segments for function: " << Function.Name
 682                     << "\n");
 683   FunctionCoverage.Segments = SegmentBuilder::buildSegments(Regions);
 684
 685   return FunctionCoverage;
 686 }
 687
 688 CoverageData CoverageMapping::getCoverageForExpansion(
 689     const ExpansionRecord &Expansion) const {
 690   CoverageData ExpansionCoverage(
 691       Expansion.Function.Filenames[Expansion.FileID]);
 692   std::vector<CountedRegion> Regions;
 693   for (const auto &CR : Expansion.Function.CountedRegions)
 694     if (CR.FileID == Expansion.FileID) {
 695       Regions.push_back(CR);
 696       if (isExpansion(CR, Expansion.FileID))
 697         ExpansionCoverage.Expansions.emplace_back(CR, Expansion.Function);
 698     }
 699
 700   LLVM_DEBUG(dbgs() << "Emitting segments for expansion of file "
 701                     << Expansion.FileID << "\n");
 702   ExpansionCoverage.Segments = SegmentBuilder::buildSegments(Regions);
 703
 704   return ExpansionCoverage;
 705 }
 706
 707 LineCoverageStats::LineCoverageStats(
 708     ArrayRef<const CoverageSegment *> LineSegments,
 709     const CoverageSegment *WrappedSegment, unsigned Line)
 710     : ExecutionCount(0), HasMultipleRegions(false), Mapped(false), Line(Line),
 711       LineSegments(LineSegments), WrappedSegment(WrappedSegment) {
 712   // Find the minimum number of regions which start in this line.
 713   unsigned MinRegionCount = 0;
 714   auto isStartOfRegion = [](const CoverageSegment *S) {
 715     return !S->IsGapRegion && S->HasCount && S->IsRegionEntry;
 716   };
 717   for (unsigned I = 0; I < LineSegments.size() && MinRegionCount < 2; ++I)
 718     if (isStartOfRegion(LineSegments[I]))
 719       ++MinRegionCount;
 720
 721   bool StartOfSkippedRegion = !LineSegments.empty() &&
 722                               !LineSegments.front()->HasCount &&
 723                               LineSegments.front()->IsRegionEntry;
 724
 725   HasMultipleRegions = MinRegionCount > 1;
 726   Mapped =
 727       !StartOfSkippedRegion &&
 728       ((WrappedSegment && WrappedSegment->HasCount) || (MinRegionCount > 0));
 729
 730   if (!Mapped)
 731     return;
 732
 733   // Pick the max count from the non-gap, region entry segments and the
 734   // wrapped count.
 735   if (WrappedSegment)
 736     ExecutionCount = WrappedSegment->Count;
 737   if (!MinRegionCount)
 738     return;
 739   for (const auto *LS : LineSegments)
 740     if (isStartOfRegion(LS))
 741       ExecutionCount = std::max(ExecutionCount, LS->Count);
 742 }
 743
 744 LineCoverageIterator &LineCoverageIterator::operator++() {
 745   if (Next == CD.end()) {
 746     Stats = LineCoverageStats();
 747     Ended = true;
 748     return *this;
 749   }
 750   if (Segments.size())
 751     WrappedSegment = Segments.back();
 752   Segments.clear();
 753   while (Next != CD.end() && Next->Line == Line)
 754     Segments.push_back(&*Next++);
 755   Stats = LineCoverageStats(Segments, WrappedSegment, Line);
 756   ++Line;
 757   return *this;
 758 }
 759
 760 static std::string getCoverageMapErrString(coveragemap_error Err) {
 761   switch (Err) {
 762   case coveragemap_error::success:
 763     return "Success";
 764   case coveragemap_error::eof:
 765     return "End of File";
 766   case coveragemap_error::no_data_found:
 767     return "No coverage data found";
 768   case coveragemap_error::unsupported_version:
 769     return "Unsupported coverage format version";
 770   case coveragemap_error::truncated:
 771     return "Truncated coverage data";
 772   case coveragemap_error::malformed:
 773     return "Malformed coverage data";
 774   }
 775   llvm_unreachable("A value of coveragemap_error has no message.");
 776 }
 777
 778 namespace {
 779
 780 // FIXME: This class is only here to support the transition to llvm::Error. It
 781 // will be removed once this transition is complete. Clients should prefer to
 782 // deal with the Error value directly, rather than converting to error_code.
 783 class CoverageMappingErrorCategoryType : public std::error_category {
 784   const char *name() const noexcept override { return "llvm.coveragemap"; }
 785   std::string message(int IE) const override {
 786     return getCoverageMapErrString(static_cast<coveragemap_error>(IE));
 787   }
 788 };
 789
 790 } // end anonymous namespace
 791
 792 std::string CoverageMapError::message() const {
 793   return getCoverageMapErrString(Err);
 794 }
 795
 796 static ManagedStatic<CoverageMappingErrorCategoryType> ErrorCategory;
 797
 798 const std::error_category &llvm::coverage::coveragemap_category() {
 799   return *ErrorCategory;
 800 }
 801
 802 char CoverageMapError::ID = 0;