[PATCH] D59553: [WIP][LLD][ELF][DebugInfo] Use predefined value to mark debug address ranges pointing to deleted code.

[Fangrui Song via Phabricator via llvm-commits]

MaskRay added a comment.

> (summary-ish: comdat functions that are optimized differently: subprograms must not refer to the differently optimized version
>  comdat functions that are optimized identically: multiple subprograms could point to the same code, but there's probably little benefit/reason to do so
>  identical unrelated functions: there's value in multiple subprograms pointing to the same code)

Resolving a (relocation referencing a symbol defined in a discarded COMDAT group) to the tombstone value may be more troublesome.

  clang -c -ffunction-sections a.cc  # no debug info
  clang -c -ffunction-sections -g b.cc

Assuming a.cc & b.cc define the same function, should the linker resolve relocations in b.o(.debug_info) to the tombstone value? Maybe not because we'll lose all debugging information.
If both a.o & b.o have debugging information, it may be reasonable to resolve relocations in b.o(.debug_info) to the tombstone value.


Repository:
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https://reviews.llvm.org/D59553