From 65a5e7129877819ebfc7723be3177b039ff11056 Mon Sep 17 00:00:00 2001
From: Justin Bogner <mail@justinbogner.com>
Date: Sat, 24 Jan 2015 20:58:52 +0000
Subject: [PATCH] llvm-cov: Only combine segments if they overlap exactly

If two coverage segments cover the same area we need to combine them,
as per r218432. OTOH, just because they start at the same place
doesn't mean they cover the same area. This fixes the check to be more
exact about this.

This is pretty hard to test right now. The frontend doesn't currently
emit regions that start at the same place but don't overlap, but some
upcoming work changes this.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227017 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/ProfileData/CoverageMapping.cpp | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/lib/ProfileData/CoverageMapping.cpp b/lib/ProfileData/CoverageMapping.cpp
index eba6b5724d6..166323a0683 100644
--- a/lib/ProfileData/CoverageMapping.cpp
+++ b/lib/ProfileData/CoverageMapping.cpp
@@ -304,13 +304,14 @@ class SegmentBuilder {
 public:
   /// Build a list of CoverageSegments from a sorted list of Regions.
   std::vector<CoverageSegment> buildSegments(ArrayRef<CountedRegion> Regions) {
+    const CountedRegion *PrevRegion = nullptr;
     for (const auto &Region : Regions) {
       // Pop any regions that end before this one starts.
       while (!ActiveRegions.empty() &&
              ActiveRegions.back()->endLoc() <= Region.startLoc())
         popRegion();
-      if (!Segments.empty() && Segments.back().Line == Region.LineStart &&
-          Segments.back().Col == Region.ColumnStart) {
+      if (PrevRegion && PrevRegion->startLoc() == Region.startLoc() &&
+          PrevRegion->endLoc() == Region.endLoc()) {
         if (Region.Kind != coverage::CounterMappingRegion::SkippedRegion)
           Segments.back().addCount(Region.ExecutionCount);
       } else {
@@ -318,6 +319,7 @@ public:
         ActiveRegions.push_back(&Region);
         startSegment(Region);
       }
+      PrevRegion = &Region;
     }
     // Pop any regions that are left in the stack.
     while (!ActiveRegions.empty())
@@ -409,6 +411,7 @@ CoverageData CoverageMapping::getCoverageForFile(StringRef Filename) {
   }
 
   sortNestedRegions(Regions.begin(), Regions.end());
+  DEBUG(dbgs() << "Emitting segments for file: " << Filename << "\n");
   FileCoverage.Segments = SegmentBuilder().buildSegments(Regions);
 
   return FileCoverage;
@@ -450,6 +453,7 @@ CoverageMapping::getCoverageForFunction(const FunctionRecord &Function) {
     }
 
   sortNestedRegions(Regions.begin(), Regions.end());
+  DEBUG(dbgs() << "Emitting segments for function: " << Function.Name << "\n");
   FunctionCoverage.Segments = SegmentBuilder().buildSegments(Regions);
 
   return FunctionCoverage;
@@ -468,6 +472,8 @@ CoverageMapping::getCoverageForExpansion(const ExpansionRecord &Expansion) {
     }
 
   sortNestedRegions(Regions.begin(), Regions.end());
+  DEBUG(dbgs() << "Emitting segments for expansion of file " << Expansion.FileID
+               << "\n");
   ExpansionCoverage.Segments = SegmentBuilder().buildSegments(Regions);
 
   return ExpansionCoverage;
-- 
2.34.1