Re: PING^2: [PATCH v3] elf: Always honor the first definition in shared object and archive

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

On Fri, Apr 5, 2024 at 4:45 PM Alan Modra <amodra@gmail.com> wrote:
>
> On Fri, Apr 05, 2024 at 04:37:11PM -0700, H.J. Lu wrote:
> > On Fri, Apr 5, 2024 at 3:16 PM Alan Modra <amodra@gmail.com> wrote:
> > >
> > > On Fri, Apr 05, 2024 at 05:00:28AM -0700, H.J. Lu wrote:
> > > > On Fri, Apr 5, 2024 at 3:15 AM Nick Clifton <nickc@redhat.com> wrote:
> > > > >
> > > > > Hi H.J.
> > > > >
> > > > > >>> GCC doesn't put builtin function symbol references, which are defined in
> > > > > >>> the shared C library, in the IR symbol table.  When linker rescans shared
> > > > > >>> objects and archives for newly added symbol references generated from the
> > > > > >>> IR inputs, it skips definitions of the builtin functions in shared
> > > > > >>> objects and archives.
> > > > > >>>
> > > > > >>> Add first_hash to elf_link_hash_table to track unreferenced definitions
> > > > > >>> defined first in shared objects and archives.  Always use them to resolve
> > > > > >>> any references.
> > > > >
> > > > > Approved - please apply.
> > > > >
> > > > > Cheers
> > > > >    Nick
> > > > >
> > > >
> > > > I am checking in the v2 patch:
> > > >
> > > > https://sourceware.org/pipermail/binutils/2024-April/133395.html
> > >
> > > I had some further requests to make.
> > > 1) If you are going to use a bfd_hash_table based first_hash, please
> > > don't use bfd_link_hash_table.  Instead extend bfd_hash_entry with a
> > > single abfd field.  You'll need to write a newfunc, but that's about
> > > all that is required.  There are multiple examples of this in the
> > > source, eg. bfd/stabs.c stab_link_includes_entry.
> >
> > I will add
> >
> > /* An entry in the first definition hash table.  */
> >
> > struct elf_link_first_hash_entry
> > {
> >   struct bfd_hash_entry root;
> >   /* The object of the first definition.  */
> >   bfd *abfd;
> > };
> >
> > > 2) You are accessing freed memory in _bfd_elf_link_hash_table_free.
> > > Free first_hash before freeing the main hash table.  That needs fixing
> > > immediately.
> >
> > I will change it to
> >
> >   if (htab->first_hash != NULL)
> >     {
> >       bfd_hash_table_free (htab->first_hash);
> >       free (htab->first_hash);
> >     }
> >   _bfd_generic_link_hash_table_free (obfd);
>
> Thanks, that along with the elf_link_first_hast_entry change is
> preapproved.

I am checking in this:

https://sourceware.org/pipermail/binutils/2024-April/133415.html

Thanks.

-- 
H.J.