[llvm] Reland [CGData] llvm-cgdata #89884 (PR #101461)

[Kyungwoo Lee via llvm-commits]

kyulee-com wrote:

> Related patches have introduced `llvm/lib/CodeGenData` and `llvm/include/llvm/CodeGenData/`. Adding new directories under `llvm/lib` and `llvm/include/llvm` require more discussions.
> 
> I think you need to ask more folks about their opinions, my intuition is that reusing `llvm/lib/Object` might be a choice. The `.cpp` files seem to use Support and Object, and therefore need to live at a layer higher than LLVMObject per https://llvm.org/docs/CodingStandards.html#library-layering

Thank you for the guidance on layering within lib and include. Based on the conventions from the link you provided, placing `CodeGenData` files under `llvm/lib/Object` is an option. However, to avoid clutter and maintain distinct functionality, a separate `CodeGenData` directory might be preferable, similar to the `ProfileData` setup which also uses `Support` and `Object`.

I'm open to other opinions on this matter. Could you please add more reviewers relevant to this discussion? If the consensus favors a different placement, I will create a separate PR (NFC) to accommodate that change, instead of making changes in place here.

https://github.com/llvm/llvm-project/pull/101461