[llvm] [DWARF] Generalize DWARFTypePrinter to a template class (PR #109459)

[Pavel Labath via llvm-commits]

https://github.com/labath commented:

> So, if some folks have opinions on if/how much we should try to merge the forks today, motivated in part by this work, I think we should have that discussion.

The problem with merging the forks is that the DWARFUnit, DWARFDie and DWARFFormValue classes are very tightly coupled (and also quite big/complex), so it's not possible to start using just one of them. The only way I see towards unification is to gradually morph one or both of the implementation towards the other until they become basically identical, swapping them becomes a no-op.

With that in mind, my opinion (others can disagree) is that we should use this opportunity to start that process and unify the interfaces (not implementations) to the extent necessary to make this template trick work. That will also include changes to the naming convention, where the obvious choice is to unify towards the llvm style. As for differences in behavior, we can discuss which choice is better/easier on a case-by-case basis.

https://github.com/llvm/llvm-project/pull/109459