InstrProf: Treat functions with a coverage map but no profile as unre…

…ached

If we have a coverage mapping but no profile data for a function,
calling it mismatched is misleading. This can just as easily be
unreachable code that was stripped from the binary. Instead, treat
these the same as functions where we have an explicit "zero" coverage
map by setting the count to zero for each mapped region.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237298 91177308-0d34-0410-b5e6-96231b3b80d8

lib/ProfileData/CoverageMapping.cpp

@@ -209,8 +209,9 @@ CoverageMapping::load(CoverageMappingReader &CoverageReader,
         continue;
       } else if (EC != instrprof_error::unknown_function)
         return EC;
-    } else
-      Ctx.setCounts(Counts);
+      Counts.assign(Record.MappingRegions.size(), 0);
+    }
+    Ctx.setCounts(Counts);
 
     assert(!Record.MappingRegions.empty() && "Function has no regions");
 

unittests/ProfileData/CoverageMappingTest.cpp

@@ -222,6 +222,21 @@ TEST_F(CoverageMappingTest, uncovered_function) {
   ASSERT_EQ(CoverageSegment(3, 4, false),   Segments[1]);
 }
 
+TEST_F(CoverageMappingTest, uncovered_function_with_mapping) {
+  readProfCounts();
+
+  addCMR(Counter::getCounter(0), "file1", 1, 1, 9, 9);
+  addCMR(Counter::getCounter(1), "file1", 1, 1, 4, 7);
+  loadCoverageMapping("func", 0x1234);
+
+  CoverageData Data = LoadedCoverage->getCoverageForFile("file1");
+  std::vector<CoverageSegment> Segments(Data.begin(), Data.end());
+  ASSERT_EQ(3U, Segments.size());
+  ASSERT_EQ(CoverageSegment(1, 1, 0, true),  Segments[0]);
+  ASSERT_EQ(CoverageSegment(4, 7, 0, false), Segments[1]);
+  ASSERT_EQ(CoverageSegment(9, 9, false),    Segments[2]);
+}
+
 TEST_F(CoverageMappingTest, combine_regions) {
   ProfileWriter.addFunctionCounts("func", 0x1234, {10, 20, 30});
   readProfCounts();