[ELF] Don't consider SHF_ALLOC ".debug*" sections debug sections
Fixes PR48071
* The Rust compiler produces SHF_ALLOC `.debug_gdb_scripts` (which
normally does not have the flag)
* `.debug_gdb_scripts` sections are removed from `inputSections` due
to --strip-debug/--strip-all
* When processing --gc-sections, pieces of a SHF_MERGE section can be
marked live separately
`=>` segfault when marking liveness of a `.debug_gdb_scripts` which
is not split into pieces (because it is not in `inputSections`)
This patch circumvents the problem by not treating SHF_ALLOC
".debug*" as debug sections (to prevent --strip-debug's stripping)
(which is still useful on its own).
Reviewed By: grimar
Differential Revision: https://reviews.llvm.org/D91291
This should fix lld segfaulting when linking the rust-based parts of the
devel/py-maturin port.
Reported by: Nick Venenga <nijave@gmail.com>
PR: 250783
MFC after: 3 days