[Coverage] Fix an issue where improper coverage mapping data could be loaded for an inline function.

If an inline function is observed but unused in a translation unit, dummy
coverage mapping data with zero hash is stored for this function.
If such a coverage mapping section came earlier than real one, the latter
was ignored. As a result, llvm-cov was unable to show coverage information
for those functions.

Differential Revision: http://reviews.llvm.org/D20286


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@270194 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 10 insertions, 0 deletions

diff --git a/include/llvm/ProfileData/Coverage/CoverageMappingReader.h b/include/llvm/ProfileData/Coverage/CoverageMappingReader.h
index ce743a96d1d..db907f128d9 100644
--- a/include/llvm/ProfileData/Coverage/CoverageMappingReader.h
+++ b/include/llvm/ProfileData/Coverage/CoverageMappingReader.h
@@ -103,6 +103,16 @@ public:
   Error read();
 };
 
+/// \brief Checks if the given coverage mapping data is exported for
+/// an unused function.
+class RawCoverageMappingDummyChecker : public RawCoverageReader {
+public:
+  RawCoverageMappingDummyChecker(StringRef MappingData)
+      : RawCoverageReader(MappingData) {}
+
+  Expected<bool> isDummy();
+};
+
 /// \brief Reader for the raw coverage mapping data.
 class RawCoverageMappingReader : public RawCoverageReader {
   ArrayRef<StringRef> TranslationUnitFilenames;