[clang] [llvm] [GCOV] Modify the path parsing of gcov instrument filter (PR #183475)

[via cfe-commits]

LeeLee26 wrote:

@MaskRay Sorry for the delay, it's been a busy month.

This issue surfaced in our distributed build system. We use symlinks (e.g., /tmp/symlink -> /tmp/real) to manage source files. Since the build commands reference the symlink path but the actual files are stored elsewhere (often hashed directories), the current behavior of canonicalizing paths (resolving symlinks) breaks our coverage filters.

This pr proposes to skip symlink resolution to ensure filter consistency. I understand that both resolving and not resolving symlinks have their own pros and cons—it’s a design trade-off we need to consider.

https://github.com/llvm/llvm-project/pull/183475