From: Alan Modra <amodra@gmail.com>
To: "H.J. Lu" <hjl.tools@gmail.com>
Cc: Nick Clifton <nickc@redhat.com>, Binutils <binutils@sourceware.org>
Subject: Re: PING^2: [PATCH v3] elf: Always honor the first definition in shared object and archive
Date: Sat, 6 Apr 2024 10:15:35 +1030 [thread overview]
Message-ID: <ZhCNH6AU46QnJJyZ@squeak.grove.modra.org> (raw)
In-Reply-To: <CAMe9rOqargXzwFVsY3G0bMZVn6DZ-9WmDawCLhZjZ8XDpkGTBQ@mail.gmail.com>
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.
> > 3) Please ensure tests have different names. This
> > [list {pr31482a} \
> > {-Wl,--no-as-needed,-R,tmpdir} {} \
> > {pr31482a.c} {pr31482a.exe} {pass.out} {-flto} {c} {} \
> > {tmpdir/pr31482b.a tmpdir/pr31482c.so}] \
> > [list {pr31482b} \
> > {-Wl,--no-as-needed,-R,tmpdir} {} \
> > {pr31482a.c} {pr31482b.exe} {pass1.out} {-flto} {c} {} \
> > {tmpdir/pr31482c.so tmpdir/pr31482b.a}] \
> > [list {pr31489a} \
> > {-Wl,--as-needed,-R,tmpdir} {} \
> > {pr31482a.c} {pr31489a.exe} {pass.out} {-flto} {c} {} \
> > {tmpdir/pr31482b.a tmpdir/pr31482c.so}] \
> > [list {pr31489b} \
> > {-Wl,--as-needed,-R,tmpdir} {} \
> > {pr31482a.c} {pr31489b.exe} {pass1.out} {-flto} {c} {} \
> > {tmpdir/pr31482c.so tmpdir/pr31482b.a}] \
> > has two tests called pr31489a and two called pr31489b.
> > "FAIL: pr31489a" as the output of make check isn't as helpful as it
> > could be. Better would be to add --no-as-needed and --as-needed to
> > the test names.
> >
>
> I got
>
> ld-plugin/lto.exp: [list {pr31489a} \
> ld-plugin/lto.exp: {pr31482a.c} {pr31489a.exe} {pass.out} {-flto} {c} {} \
>
> and
>
> ld-plugin/lto.exp: [list {pr31489b} \
> ld-plugin/lto.exp: {pr31482a.c} {pr31489b.exe} {pass1.out} {-flto} {c} {} \
>
> I only saw one pr31489a and one pr31489b. Where are
> the second ones?
Oops. You chose different pr numbers. I can't read, sorry. :-(
--
Alan Modra
Australia Development Lab, IBM
next prev parent reply other threads:[~2024-04-05 23:45 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-15 19:43 H.J. Lu
2024-03-28 13:30 ` PING: " H.J. Lu
2024-04-04 13:29 ` PING^2: " H.J. Lu
2024-04-05 10:15 ` Nick Clifton
2024-04-05 12:00 ` H.J. Lu
2024-04-05 22:16 ` Alan Modra
2024-04-05 23:37 ` H.J. Lu
2024-04-05 23:45 ` Alan Modra [this message]
2024-04-05 23:48 ` H.J. Lu
2024-04-04 23:54 ` Alan Modra
2024-04-05 1:50 ` H.J. Lu
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