[llvm] [llvm-cov] - Output better error message when the error kind is `coveragemap_error::malforme`. (PR #65264)

[Fangrui Song via llvm-commits]

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@@ -634,7 +648,9 @@ class VersionedCovMapFuncRecordReader : public CovMapFuncRecordReader {
 
     // Get the filenames.
     if (CovBuf + FilenamesSize > CovBufEnd)
-      return make_error<CoverageMapError>(coveragemap_error::malformed);
+      return make_error<CoverageMapError>(
+          coveragemap_error::malformed,
+          "filenames section is greater than buffer size");
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MaskRay wrote:

larger

https://github.com/llvm/llvm-project/pull/65264