[llvm] [AIX][XCOFF] rename metadata (PR #159435)

[Sean Fertile via llvm-commits]

mandlebug wrote:

> As a start, in XCOFF, we will only accept a very limited form of COMDAT (the above).

I think it would be pretty confusing to support a subset of COMDAT, especially on a platform that doesn't natively support any of the other comdat features. An IR producer that's not intimately familiar with the specifics of the AIX object format would have a hard time understanding what they could and couldn't emit or why there are any limitations to begin with. I see why you would suggest that though as we are solving  the same problem with the use of .ref and  .rename that the section keys solves on ELF, and I think in the same vein not may developers know when they need to apply this behaviour to not break linking garbage collection.

https://github.com/llvm/llvm-project/pull/159435