[llvm] [DebugInfo] Emit linkage name into DWARF for types for Swift (PR #112802)

[David Blaikie via llvm-commits]

dwblaikie wrote:

> I've restricted emitting linkage names into accelerator tables to Swift only since some tests were failing it should be the only language (as far as I'm aware) that uses mangled names for types pervasively anyway.

The `identifier` field is used for any producer that wants to deduplicate type information - either in LTO at the LLVM IR level, or also in the DWARF (using DWARF type units) at the (ELF only, I think) object level. So, yeah, reusing it for a fairly different debugger interaction probably needs to be restricted to Swift - but also may present complications for Swift on ELF, since it might confuse the two signals/uses of the identifier field... not sure what, if anything, to do about that.

https://github.com/llvm/llvm-project/pull/112802