Re: [PATCH] ld: Keep indirect symbol from IR if referenced from shared object

[Alan Modra <amodra@gmail.com>]

On Sun, Feb 13, 2022 at 06:58:48PM -0800, H.J. Lu wrote:
> On Sun, Feb 13, 2022 at 6:47 PM Alan Modra <amodra@gmail.com> wrote:
> >
> > On Sun, Feb 13, 2022 at 04:16:35PM -0800, H.J. Lu wrote:
> > > On Fri, Feb 11, 2022 at 3:19 PM H.J. Lu <hjl.tools@gmail.com> wrote:
> > > >
> > > > Don't change indirect symbol defined in IR to undefined if it is
> > > > referenced from shared object.
> >
> > The description above
> >
> > > > diff --git a/bfd/elflink.c b/bfd/elflink.c
> > > > index 6fa18d92007..f8521426cad 100644
> > > > --- a/bfd/elflink.c
> > > > +++ b/bfd/elflink.c
> > > > @@ -1294,9 +1294,8 @@ _bfd_elf_merge_symbol (bfd *abfd,
> > > >           h->root.non_ir_ref_dynamic = true;
> > > >           hi->root.non_ir_ref_dynamic = true;
> > > >         }
> > > > -
> > > > -      if ((oldbfd->flags & BFD_PLUGIN) != 0
> > > > -         && hi->root.type == bfd_link_hash_indirect)
> > > > +      else if ((oldbfd->flags & BFD_PLUGIN) != 0
> > > > +              && hi->root.type == bfd_link_hash_indirect)
> > > >         {
> > > >           /* Change indirect symbol from IR to undefined.  */
> > > >           hi->root.type = bfd_link_hash_undefined;
> >
> > and the patch do not exactly match.  The code logic is old sym
> > indirect in IR, new sym not IR, both in shared library *or both not*.
> > Is that correct?
> >
> 
> The existing code is
> 
>       if (newdyn != olddyn)
>         {
>           /* Handle a case where plugin_notice won't be called and thus
>              won't set the non_ir_ref flags on the first pass over
>              symbols.  */
>           h->root.non_ir_ref_dynamic = true;
>           hi->root.non_ir_ref_dynamic = true;
>         }
> 
> If an indirect symbol defined in IR is marked with
> non_ir_ref_dynamic, we can't change it to undefined.
> That is why I added "else" so that we don't get the
> error of undefined reference from shared object.

The patch is OK, I wasn't thinking clearly.

>       if ((oldbfd->flags & BFD_PLUGIN) != 0
>           && hi->root.type == bfd_link_hash_indirect)
>         {
>           /* Change indirect symbol from IR to undefined.  */
>           hi->root.type = bfd_link_hash_undefined;
>           hi->root.u.undef.abfd = oldbfd;
>         }
> 
> 
> -- 
> H.J.

-- 
Alan Modra
Australia Development Lab, IBM