[PATCH 2/3] gas/ELF: warn upon non-default visibility of local symbols

[H.J. Lu]

On Fri, May 8, 2026 at 2:54 PM Jan Beulich <jbeulich@suse.com> wrote:
>
> On 10.04.2026 16:17, Jan Beulich wrote:
> > On 10.04.2026 15:35, Richard Earnshaw (foss) wrote:
> >> On 10/04/2026 14:31, Jan Beulich wrote:
> >>> The spec explicitly precludes STB_LOCAL together with STV_PROTECTED (and,
> >>> implicity, STV_HIDDEN or STV_INTERNAL), so we better wouldn't entirely
> >>> silently write out symbols violating this.
> >>>
> >>> LoongArch's tc_symbol_new_hook() simply needs dropping. If FAKE_LABEL_NAME
> >>> symbols can end up global, marking them hidden would need doing elsewhere.
> >>> There not being a need to make any testsuite adjustments suggests though
> >>> that this won't normally (ever?) happen.
> >>>
> >>> A couple of testcases then also need adjustment.
> >>> ---
> >>> It would be nice to re-use an existing loop, yet the one in
> >>> elf_frob_file_before_adjust() comes too early, as does elf_frob_symbol().
> >>>
> >>> An alternative may be to imply .global from .hidden etc also for defined
> >>> symbols (as looks to have been implied by some of the testcases being
> >>> adjusted). This would then require to reject .local when a visibility was
> >>> already set.
> >
> > As you can see from this, ...
> >
> >>> I wonder what purpose STV_* serve with e.g. STT_SECTION. Yet I also wonder
> >>> what purpose STB_* other than STB_LOCAL serve with STT_SECTION (seeing how
> >>> bfd/elf.c:swap_out_syms() explicitly uses STB_GLOBAL).
> >>>
> >>> The TI C6x testcase adjustments suggest that PLT relocations are
> >>> needlessly emitted by gas for non-default visibility globals.
> >>
> >>
> >> Do we know that this won't cause issues for real code out in the wild?  Might it not be better to just treat .hidden as making the symbol global, but hidden?
> >
> > ... I'm wondering the same. I meant to be conservative (as to exposing new
> > globals) for v1. If collectively we think changing the behavior that way
> > makes sense, I'll be happy to try that out for v2.
>
> Having thought about this more, implying global from hidden (etc) feels more
> risky than keeping things as they are in v1: People suddenly may face
> duplicate symbol linker errors that way. Short of any other comments /
> opinions, I'll get the series in as is.
>

This warning isn't very useful and annoying:

https://sourceware.org/bugzilla/show_bug.cgi?id=34312


--
H.J.