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Re: [PATCH] PR ld/21233: Avoid sweeping forced-undefined symbols in section GC
On Wed, 5 Apr 2017, Alan Modra wrote:
> > I suspect some targets might not have a psABI as simple as that however
> > and might require (or just want) a copy relocation even where the only
> > reference is a static pointer from data, and these might indeed rely on
> > the relative order `elf_gc_sweep' and `_bfd_elf_link_check_relocs' are
> > called in.
> The test has a reference from .data to "bar" that sets non_got_ref and
> pointer_equality_needed, increments plt.refcount in case "bar" turns
> out to be a function, and records the need for a possible dynamic
> reloc in dyn_relocs, in check_relocs on powerpc64le. .data is then
> garbage collected, which removes the dyn_reloc entry and decrements
> plt.refcount too (*) in gc_sweep_hook but can't remove flags like
> non_got_ref. ppc64_elf_adjust_dynamic_symbol does clear non_got_ref
> later, and doesn't make a nonsense entry in .dynbss with copy relocs.
> *) plt.refcount isn't decremented in this case on ppc64le. Bug! So
> it was worth looking at the testcase. :)
Fair enough. I'm glad you've found my test case useful. :)
> > Committed unchanged then. Any issue with backporting it to 2.28, as per
> > the situation with the problem report?
> I think backporting should omit the testcase, to avoid unduly worrying
I thought so as well as I was asking my question, but didn't want to
suggest the answer. ;) I've backported the fix itself only then to 2.28,
and closed the PR now.
Thanks for your input.