[llvm] [LLVM][AArch64] Build attributes: Support switching to a defined subsection by name only (PR #154159)

[Peter Smith via llvm-commits]

https://github.com/smithp35 commented:

Change matches the updated assembly specification. This does not change any existing use of the directive.

I have a suggestion to simplify the code. I think we should keep the API as small as we can. For example only one way to find an existing subsection, and one way to change to it.

https://github.com/llvm/llvm-project/pull/154159