[Coverage] Ensure that coverage mapping data has an expected alignment in 'covmapping' files.
Coverage mapping data is organized in a sequence of blocks, each of which is expected
to be aligned by 8 bytes. This feature is used when reading those blocks, see
VersionedCovMapFuncRecordReader::readFunctionRecords(). If a misaligned covearge
mapping data has more than one block, it causes llvm-cov to fail.
Differential Revision: http://reviews.llvm.org/D20285
llvm-svn: 269887
diff --git a/llvm/lib/ProfileData/Coverage/CoverageMappingReader.cpp b/llvm/lib/ProfileData/Coverage/CoverageMappingReader.cpp
index 9f27de9..9920c33 100644
--- a/llvm/lib/ProfileData/Coverage/CoverageMappingReader.cpp
+++ b/llvm/lib/ProfileData/Coverage/CoverageMappingReader.cpp
@@ -491,6 +491,13 @@
return coveragemap_error::malformed;
ProfileNames.create(Data.substr(0, ProfileNamesSize), Address);
CoverageMapping = Data.substr(ProfileNamesSize);
+ // Skip the padding bytes because coverage map data has an alignment of 8.
+ if (CoverageMapping.size() < 1)
+ return coveragemap_error::truncated;
+ size_t Pad = alignmentAdjustment(CoverageMapping.data(), 8);
+ if (CoverageMapping.size() < Pad)
+ return coveragemap_error::malformed;
+ CoverageMapping = CoverageMapping.substr(Pad);
return std::error_code();
}