https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98121
--- Comment #8 from Jozef Lawrynowicz <jozefl at gcc dot gnu.org> ---
(In reply to Jozef Lawrynowicz from comment #7)
> (In reply to Florian Weimer from comment #6)
> > (In reply to Jozef Lawrynowicz from comment #4)
> > > GAS merges the "R" flag state in .section declarations, silently, and with
> > > logical OR, and GCC should do the same. So if you have:
> > >
> > > int __attribute__((section(".data.foo"))) foo1 = 1;
> > > int __attribute__((used,section(".data.foo"))) foo2 = 2;
> > >
> > > .data.foo should have SECTION_RETAIN set within GCC. The addition of the
> > > "used" attribute to the second declaration of section(".data.foo") should
> > > not cause any warning/error messages to be emitted either. So option 3
> > > from
> > > above.
> > >
> > > Just need to do something similar to what is already done for
> > > SECTION_NOTYPE
> > > in varasm.c:get_section.
> >
> > I don't now the details, but I think foo1 should not implicitly be marked as
> > “used”. The difference matters for static functions, for example. GCC should
> > still drop them if they are not referenced, even if they are located in a
> > retained section. So free_slotinfo in comment 5.
>
> With the suggested approach, GCC would still drop foo1 if it is not used,
> since it is only the section being marked with SECTION_RETAIN, and this only
> affects whether the "R" flag is output in the .section directive for the
> decl.
>
> GCC will only keep an unreferenced decl if it has DECL_PRESERVE_P and we
> haven't changed that with the "used" applies SHF_GNU_RETAIN functionality.
>
> If foo1 somehow makes it into the assembler code, it will be kept, even if
> it is not used, since we lose the ability to remove individual decls once
> they are put in sections.
Sorry, in my foo1/foo2 example they are not static so will not be dropped by
GCC.
For the free_slotinfo example, it would be dropped by GCC if unused, even
though another function with the same section was marked "used" and has
SECTION_RETAIN.
