[llvm] Optionally print `!prof` metadata inline (PR #130303)

[Teresa Johnson via llvm-commits]

teresajohnson wrote:

> It may be more generally useful to have a flag for printing instruction and GV metadata inline (one level of expansion) instead of having a special case for `!prof`. This could also be useful for CFI, e.g.
> 
> ```
> @foo = constant i32 0, type !12345
> !12345 = !{i64 0, !"foo"}
> ```
> 
> becomes
> 
> ```
> @foo = constant i32 0, !type !{i64 0, !"foo"}
> ```
> 
> IIRC inline metadata is parsed as expected so this could be useful for developers who are manually editing metadata e.g. for test cases.

I was thinking about suggesting that too, but there may be complications for metadata that references other metadata. I'm not sure how that gets rendered automatically, and whether and how much to expand it inline, and what would happen when parsed again. But yes, a broader expansion to other metadata types could be very useful.

https://github.com/llvm/llvm-project/pull/130303