[llvm] [RFC] Emit dwarf data for signature-changed or new functions (PR #157349)

[Vladislav Dzhidzhoev via llvm-commits]

dzhidzhoev wrote:

> Thanks! So the idea is to the actual function itself has tag for the original subprogram, but the the code in the actual function has tags for the modified subprogram. This may work. Will give a try.

To avoid misunderstanding, in my example,`LOC_A: DW_TAG_subprogram` corresponds to !0, second `DW_TAG_subprogram` corresponds to !10, and !10 is attached to @_Z3mulii after EmitChangedFuncDebugInfo.

https://github.com/llvm/llvm-project/pull/157349