[llvm] [Tablegen] Add keyword `dump`. (PR #68793)

[Francesco Petrogalli via llvm-commits]

fpetrogalli wrote:

@Artem-B 

>  I wonder what the dump from multiple instances of in-multiclass dump would look like. Can we tell them apart somehow? I think they all will be attributed to the source location of the dump itself. I think we'll need some sort of reference to the instantiation point, too.

I like this a lot - it can get nasty if someone start using dump statements across layers of class/multiclass indirection.
I actually had the same issue with assert, which does not come as surprise given the similarities with dump.

> Not sure if it's worth it, but I think it would be useful. We can consider it as a follow-up change.

If this is OK with you, I will create an issue and link it to this PR.

https://github.com/llvm/llvm-project/pull/68793