Coverage: add HasCodeBefore flag to a mapping region.

This flag will be used by the coverage tool to help 
compute the execution counts for each line in a source file.

Differential Revision: http://reviews.llvm.org/D4746

llvm-svn: 214740

1 files changed, 5 insertions, 1 deletions

diff --git a/llvm/lib/ProfileData/CoverageMappingWriter.cpp b/llvm/lib/ProfileData/CoverageMappingWriter.cpp
index f9bbe61fb48..f5e6ab46380 100644
--- a/llvm/lib/ProfileData/CoverageMappingWriter.cpp
+++ b/llvm/lib/ProfileData/CoverageMappingWriter.cpp
@@ -181,7 +181,11 @@ void CoverageMappingWriter::write(raw_ostream &OS) {
     }
     assert(I.LineStart >= PrevLineStart);
     encodeULEB128(I.LineStart - PrevLineStart, OS);
-    encodeULEB128(I.ColumnStart, OS);
+    uint64_t CodeBeforeColumnStart =
+        uint64_t(I.HasCodeBefore) |
+        (uint64_t(I.ColumnStart)
+         << CounterMappingRegion::EncodingHasCodeBeforeBits);
+    encodeULEB128(CodeBeforeColumnStart, OS);
     assert(I.LineEnd >= I.LineStart);
     encodeULEB128(I.LineEnd - I.LineStart, OS);
     encodeULEB128(I.ColumnEnd, OS);