[PATCH] D18610: [PGO] Restore the correct counter value after processing a nested region in case of combined regions.

Igor Kudrin via llvm-commits llvm-commits at lists.llvm.org
Thu Apr 7 08:54:14 PDT 2016


Thanks! I'll first prepare a new variant, as David proposed, and then 
we'll judge, which one is better.

On 06.04.2016 23:48, Justin Bogner wrote:
> Igor Kudrin <ikudrin.dev at gmail.com> writes:
>> ikudrin updated this revision to Diff 52230.
>> ikudrin added a comment.
>>
>> Thanks a lot for the comments! Please review the new version of the code.
>>
>> - Added a new unit test.
>> - Eliminated dead code.
>> - Reworked the whole SegmentBuilder class.
>> - Addressed all other comments.
> LGTM. Thanks!
>
>> http://reviews.llvm.org/D18610
>>
>> Files:
>>    llvm/trunk/include/llvm/ProfileData/CoverageMapping.h
>>    llvm/trunk/lib/ProfileData/CoverageMapping.cpp
>>    llvm/trunk/test/tools/llvm-cov/showTemplateInstantiations.cpp
>>    llvm/trunk/unittests/ProfileData/CoverageMappingTest.cpp
>>
>> Index: llvm/trunk/unittests/ProfileData/CoverageMappingTest.cpp
>> ===================================================================
>> --- llvm/trunk/unittests/ProfileData/CoverageMappingTest.cpp
>> +++ llvm/trunk/unittests/ProfileData/CoverageMappingTest.cpp
>> @@ -269,6 +269,25 @@
>>     ASSERT_EQ(CoverageSegment(9, 9, false), Segments[3]);
>>   }
>>   
>> +TEST_P(MaybeSparseCoverageMappingTest, restore_combined_counter_after_nested_region) {
>> +  InstrProfRecord Record("func", 0x1234, { 10, 20, 40 });
>> +  ProfileWriter.addRecord(std::move(Record));
>> +  readProfCounts();
>> +
>> +  addCMR(Counter::getCounter(0), "file1", 1, 1, 9, 9);
>> +  addCMR(Counter::getCounter(1), "file1", 1, 1, 9, 9);
>> +  addCMR(Counter::getCounter(2), "file1", 3, 3, 5, 5);
>> +  loadCoverageMapping("func", 0x1234);
>> +
>> +  CoverageData Data = LoadedCoverage->getCoverageForFile("file1");
>> +  std::vector<CoverageSegment> Segments(Data.begin(), Data.end());
>> +  ASSERT_EQ(4U, Segments.size());
>> +  ASSERT_EQ(CoverageSegment(1, 1, 30, true), Segments[0]);
>> +  ASSERT_EQ(CoverageSegment(3, 3, 40, true), Segments[1]);
>> +  ASSERT_EQ(CoverageSegment(5, 5, 30, false), Segments[2]);
>> +  ASSERT_EQ(CoverageSegment(9, 9, false), Segments[3]);
>> +}
>> +
>>   TEST_P(MaybeSparseCoverageMappingTest, dont_combine_expansions) {
>>     InstrProfRecord Record1("func", 0x1234, {10, 20});
>>     InstrProfRecord Record2("func", 0x1234, {0, 0});
>> Index: llvm/trunk/test/tools/llvm-cov/showTemplateInstantiations.cpp
>> ===================================================================
>> --- llvm/trunk/test/tools/llvm-cov/showTemplateInstantiations.cpp
>> +++ llvm/trunk/test/tools/llvm-cov/showTemplateInstantiations.cpp
>> @@ -7,10 +7,10 @@
>>   int func(T x) {      // ALL-NEXT:    2| [[@LINE]]|int func(T x) {
>>     if(x)              // ALL-NEXT:    2| [[@LINE]]|  if(x)
>>       return 0;        // ALL-NEXT:    1| [[@LINE]]|    return 0;
>> -  else               // ALL-NEXT:    1| [[@LINE]]|  else
>> +  else               // ALL-NEXT:    2| [[@LINE]]|  else
>>       return 1;        // ALL-NEXT:    1| [[@LINE]]|    return 1;
>>     int j = 1;         // ALL-NEXT:    0| [[@LINE]]|  int j = 1;
>> -}                    // ALL-NEXT:    1| [[@LINE]]|}
>> +}                    // ALL-NEXT:    2| [[@LINE]]|}
>>   
>>                        // CHECK:       {{^ *(\| )?}}_Z4funcIbEiT_:
>>                        // CHECK-NEXT:  1| [[@LINE-9]]|int func(T x) {
>> Index: llvm/trunk/lib/ProfileData/CoverageMapping.cpp
>> ===================================================================
>> --- llvm/trunk/lib/ProfileData/CoverageMapping.cpp
>> +++ llvm/trunk/lib/ProfileData/CoverageMapping.cpp
>> @@ -273,71 +273,76 @@
>>   
>>   class SegmentBuilder {
>>     std::vector<CoverageSegment> Segments;
>> -  SmallVector<const CountedRegion *, 8> ActiveRegions;
>> +  /// Each entry corresponds to the area of code covered by one or more regions
>> +  /// with the same bounds. It consists of the first region found for that area
>> +  /// and the combined counter.
>> +  SmallVector<std::pair<const CountedRegion *, Optional<uint64_t>>, 8>
>> +      ActiveRegions;
>>   
>> -  /// Start a segment with no count specified.
>> -  void startSegment(unsigned Line, unsigned Col) {
>> -    DEBUG(dbgs() << "Top level segment at " << Line << ":" << Col << "\n");
>> -    Segments.emplace_back(Line, Col, /*IsRegionEntry=*/false);
>> -  }
>> -
>> -  /// Start a segment with the given Region's count.
>> +  /// Start a segment at the given position with the given count.
>>     void startSegment(unsigned Line, unsigned Col, bool IsRegionEntry,
>> -                    const CountedRegion &Region) {
>> -    if (Segments.empty())
>> -      Segments.emplace_back(Line, Col, IsRegionEntry);
>> -    CoverageSegment S = Segments.back();
>> +                    const Optional<uint64_t> &Count) {
>>       // Avoid creating empty regions.
>> -    if (S.Line != Line || S.Col != Col) {
>> -      Segments.emplace_back(Line, Col, IsRegionEntry);
>> -      S = Segments.back();
>> -    }
>> +    if (!Segments.empty() && Segments.back().Line == Line &&
>> +        Segments.back().Col == Col)
>> +      Segments.pop_back();
>>       DEBUG(dbgs() << "Segment at " << Line << ":" << Col);
>> -    // Set this region's count.
>> -    if (Region.Kind != coverage::CounterMappingRegion::SkippedRegion) {
>> -      DEBUG(dbgs() << " with count " << Region.ExecutionCount);
>> -      Segments.back().setCount(Region.ExecutionCount);
>> -    }
>> +    if (Count.hasValue()) {
>> +      DEBUG(dbgs() << " with count " << Count.getValue());
>> +      Segments.emplace_back(Line, Col, Count.getValue(), IsRegionEntry);
>> +    } else
>> +      Segments.emplace_back(Line, Col, IsRegionEntry);
>>       DEBUG(dbgs() << "\n");
>>     }
>>   
>> -  /// Start a segment for the given region.
>> -  void startSegment(const CountedRegion &Region) {
>> -    startSegment(Region.LineStart, Region.ColumnStart, true, Region);
>> +  /// Add the region to the top of the active stack and start
>> +  /// a new segment with the given count.
>> +  void pushRegion(const CountedRegion *Region,
>> +                  const Optional<uint64_t> &Count) {
>> +    startSegment(Region->LineStart, Region->ColumnStart, true, Count);
>> +    ActiveRegions.emplace_back(Region, Count);
>>     }
>>   
>>     /// Pop the top region off of the active stack, starting a new segment with
>>     /// the containing Region's count.
>>     void popRegion() {
>> -    const CountedRegion *Active = ActiveRegions.back();
>> -    unsigned Line = Active->LineEnd, Col = Active->ColumnEnd;
>> +    const CountedRegion *Active = ActiveRegions.back().first;
>>       ActiveRegions.pop_back();
>> -    if (ActiveRegions.empty())
>> -      startSegment(Line, Col);
>> -    else
>> -      startSegment(Line, Col, false, *ActiveRegions.back());
>> +    Optional<uint64_t> Count = None;
>> +    if (!ActiveRegions.empty())
>> +      Count = ActiveRegions.back().second;
>> +    startSegment(Active->LineEnd, Active->ColumnEnd, false, Count);
>>     }
>>   
>>   public:
>>     /// Build a list of CoverageSegments from a sorted list of Regions.
>>     std::vector<CoverageSegment> buildSegments(ArrayRef<CountedRegion> Regions) {
>> -    const CountedRegion *PrevRegion = nullptr;
>> +    const CountedRegion *ReferenceRegion = nullptr;
>> +    Optional<uint64_t> Count = None;
>>       for (const auto &Region : Regions) {
>> +      // Combine counters of the regions which cover the same area.
>> +      if (ReferenceRegion && ReferenceRegion->startLoc() == Region.startLoc() &&
>> +          ReferenceRegion->endLoc() == Region.endLoc()) {
>> +        if (Region.Kind == coverage::CounterMappingRegion::CodeRegion)
>> +          Count = Count.getValueOr(0) + Region.ExecutionCount;
>> +        continue;
>> +      }
>> +      // Add the previous region with the combined counter to the stack.
>> +      if (ReferenceRegion)
>> +        pushRegion(ReferenceRegion, Count);
>>         // Pop any regions that end before this one starts.
>>         while (!ActiveRegions.empty() &&
>> -             ActiveRegions.back()->endLoc() <= Region.startLoc())
>> +             ActiveRegions.back().first->endLoc() <= Region.startLoc())
>>           popRegion();
>> -      if (PrevRegion && PrevRegion->startLoc() == Region.startLoc() &&
>> -          PrevRegion->endLoc() == Region.endLoc()) {
>> -        if (Region.Kind == coverage::CounterMappingRegion::CodeRegion)
>> -          Segments.back().addCount(Region.ExecutionCount);
>> -      } else {
>> -        // Add this region to the stack.
>> -        ActiveRegions.push_back(&Region);
>> -        startSegment(Region);
>> -      }
>> -      PrevRegion = &Region;
>> +      ReferenceRegion = &Region;
>> +      if (Region.Kind != coverage::CounterMappingRegion::SkippedRegion)
>> +        Count = Region.ExecutionCount;
>> +      else
>> +        Count = None;
> I might've written this like so:
>
>        Count = Region.Kind == coverage::CounterMappingRegion::SkippedRegion
>                    ? None
>                    : Region.ExecutionCount;
>
> Up to you though, both ways are fine.
>
>>       }
>> +    // Add the last region to the stack.
>> +    if (ReferenceRegion)
>> +      pushRegion(ReferenceRegion, Count);
>>       // Pop any regions that are left in the stack.
>>       while (!ActiveRegions.empty())
>>         popRegion();
>> Index: llvm/trunk/include/llvm/ProfileData/CoverageMapping.h
>> ===================================================================
>> --- llvm/trunk/include/llvm/ProfileData/CoverageMapping.h
>> +++ llvm/trunk/include/llvm/ProfileData/CoverageMapping.h
>> @@ -370,13 +370,6 @@
>>       return std::tie(L.Line, L.Col, L.Count, L.HasCount, L.IsRegionEntry) ==
>>              std::tie(R.Line, R.Col, R.Count, R.HasCount, R.IsRegionEntry);
>>     }
>> -
>> -  void setCount(uint64_t NewCount) {
>> -    Count = NewCount;
>> -    HasCount = true;
>> -  }
>> -
>> -  void addCount(uint64_t NewCount) { setCount(Count + NewCount); }
>>   };
>>   
>>   /// \brief Coverage information to be processed or displayed.



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