[llvm] [RFC][LLVM] Emit dwarf data for changed-signature and new functions (PR #165310)

[via llvm-commits]

yonghong-song wrote:

Two things for this new revision:
  - Removed option 'skip-dotted-func' in EmitChangedFuncDebugInfo.cpp. This option intends to allow not generating debuginfo subprograms like `<foo>.llvm.<hash>`. During discussion in bpf mailing list (https://lore.kernel.org/bpf/20251111170424.286892-1-yonghong.song@linux.dev/), the recommendation is to have functions like <foo>.llvm.<hash> in dwarf.
  - Previously, for functions like <foo>.llvm.<hash>, we will have name '<foo>' and linkage name '<foo>.llvm.<hash>' so pahole will generate two function entries. But since the actual function is <foo>.llvm.<hash>, and function '<foo>' does not really exist in symbols, so the generated debuginfo subprogram will have name '<foo>.llvm.<hash>' and the linkage name will be NULL.

https://github.com/llvm/llvm-project/pull/165310