[C++20] [Modules] -print-library-module-manifest-path is broken now

[ChuanqiXu9]

See #73089 (comment)

After the modules are installed properly, we can find the manifest file with -print-file-name but not with -print-library-module-manifest-path. This is not intentional and we should fix this.

[llvmbot]

@llvm/issue-subscribers-clang-modules

Author: Chuanqi Xu (ChuanqiXu9)

See https://github.com//issues/73089#issuecomment-2196357282

After the modules are installed properly, we can find the manifest file with -print-file-name but not with -print-library-module-manifest-path. This is not intentional and we should fix this.

[mordante]

Thanks for creating the bug. Do you have time to look into this before the LLVM-19 release?

[ChuanqiXu9]

Thanks for creating the bug. Do you have time to look into this before the LLVM-19 release?

I may take a try but I can't make a promise.

[ChuanqiXu9]

Thanks for creating the bug. Do you have time to look into this before the LLVM-19 release?

hmm it looks like I can't reproduce this. Did you reproduce this before?

[mordante]

I can reproduce it on my Debian system

<NOT PRESENT>
$ clang++-19 --print-file-name libc++.modules.json
/usr/lib/llvm-19/bin/../lib/libc++.modules.json

If you need the output of other commands please let me know.

[ChuanqiXu9]

Thanks. But it might be hard for me to develop without being able to reproduce it...