[llvm-branch-commits] [llvm] [llvm][EmbedBitcodePass] Prevent modifying the module with ThinLTO (PR #139999)

[Paul Kirth via llvm-branch-commits]

ilovepi wrote:

I'm testing the release branch now. I believe that the issue w/ cloning was solved before we cut the release, and the patch above just added regression tests, so I expect it to work.

I'm all ears if you can think of a better way to handle this on main. The main problem I saw as I looked was that there isn't a good way to figure out what ThinLTOBitcodeWriter changed in the module (e.g. did it remove a comdat, change a linkage, etc.). We want those things to happen for the ThinLTO bitcode, but its awfully problematic for the rest of the compile. I guess we could add some metadata to the instructions we changed and then clean up after, but that also seems to not be great.

https://github.com/llvm/llvm-project/pull/139999