[clang] [ASTWriter] Detect more non-affecting FileIDs to reduce source location duplication (PR #112015)

[Jan Svoboda via cfe-commits]

https://github.com/jansvoboda11 commented:

Thanks for trying to find an alternative solution!

> However, when reading the .pcm files, we will reuse the FileID loaded from it for the same module map file and the FileID we created can never be used again, but we will still not mark it as affecting and it will take the source location space in the output PCM.

Did you mean _"mark it as affecting"_ / _"not mark it as **non**-affecting"_ instead of _"**not** mark it as affecting"_?

> I take extra care to still write the InputFile entries for those files, which has not been done before. It is required for ClangScanDeps to properly function.

Can you expand on that? Why doesn't it work properly if you stop writing those input files as well?

https://github.com/llvm/llvm-project/pull/112015