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

["H.J. Lu" <hjl.tools@gmail.com>]

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.

      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.