From: Alan Modra <amodra@gmail.com>
To: Kaylee Blake <klkblake@gmail.com>
Cc: Binutils <binutils@sourceware.org>
Subject: Re: RFC: [PATCH] ELF: Don't require section header on ELF objects
Date: Mon, 9 Mar 2020 12:53:09 +1030 [thread overview]
Message-ID: <20200309022309.GK5384@bubble.grove.modra.org> (raw)
In-Reply-To: <0ad58560-3dd4-badd-5661-9f74905a7df3@gmail.com>
On Mon, Mar 09, 2020 at 12:29:48PM +1030, Kaylee Blake wrote:
> On 9/3/20 12:06 pm, H.J. Lu wrote:
> > On Sun, Mar 8, 2020 at 5:05 PM Alan Modra <amodra@gmail.com> wrote:
> >> Well we certainly don't do such sorting. For example, from a freshly
> >> build ld/ld-new --enable-targets=all
> >>
> >> 148: 0000000000f08380 4 OBJECT GLOBAL DEFAULT 25 opterr@GLIBC_2.2.5 (3)
> >> 149: 0000000000402f80 0 FUNC GLOBAL DEFAULT UND calloc@GLIBC_2.2.5 (3)
> >> 150: 0000000000881536 35 FUNC GLOBAL DEFAULT 13 _obstack_allocated_p
> >>
> >
> > I will make 2 changes:
> >
> > 1. Update -z nosectionheader to guarantee that the last entry in
> > dynamic symbol table
> > is defined.
> > 2. Update --remove-section-header to issue an error if the last entry
> > in dynamic symbol
> > table is undefined.
> >
>
> With some testing, it seems like ld will emit an ordered symbol table
> iff it's using the DT_GNU_HASH hash table style
It doesn't. The snippet of .dynsym I posted was from a binary with
DT_GNU_HASH. elflink.c:_bfd_elf_link_renumber_dynsyms should convince
you that any ordering seen is by chance.
>, and my understanding is
> that DT_GNU_HASH in fact requires this behaviour.
Apparently not. ;-)
> So in that case, we
> don't need to do an additional check, because we only need the ordering
> if we are looking up through DT_GNU_HASH instead of DT_HASH.
>
> --
> Kaylee Blake <klkblake@gmail.com>
> C is the worst language, except for all the others.
--
Alan Modra
Australia Development Lab, IBM
next prev parent reply other threads:[~2020-03-09 2:23 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-08 17:59 H.J. Lu
2020-03-08 18:06 ` H.J. Lu
2020-03-08 23:35 ` Alan Modra
2020-03-08 23:46 ` H.J. Lu
2020-03-09 0:02 ` H.J. Lu
2020-03-09 0:02 ` Kaylee Blake
2020-03-09 0:05 ` Alan Modra
2020-03-09 1:36 ` H.J. Lu
2020-03-09 1:59 ` Kaylee Blake
2020-03-09 2:23 ` Alan Modra [this message]
2020-03-09 2:35 ` H.J. Lu
2020-03-09 4:14 ` H.J. Lu
2020-03-09 4:59 ` Kaylee Blake
2020-03-09 11:56 ` Alan Modra
2020-03-08 23:24 ` Kaylee Blake
2020-03-08 23:29 ` H.J. Lu
2020-03-08 23:38 ` Alan Modra
2020-03-08 23:45 ` H.J. Lu
2020-03-12 2:14 ` Fangrui Song
2020-03-09 8:13 ` Florian Weimer
2020-03-09 12:54 ` Kaylee Blake
2020-03-09 13:06 ` Florian Weimer
2020-03-09 13:14 ` Kaylee Blake
2020-03-09 13:16 ` Florian Weimer
2020-03-09 13:28 ` Kaylee Blake
2020-03-09 13:29 ` Florian Weimer
2020-03-09 13:45 ` Kaylee Blake
2020-03-09 13:54 ` H.J. Lu
2020-03-09 14:02 ` Kaylee Blake
2020-03-09 14:52 ` Florian Weimer
2020-03-09 15:07 ` Kaylee Blake
2020-03-09 15:29 ` Florian Weimer
2020-03-09 13:44 ` Alan Modra
2020-03-09 13:54 ` Kaylee Blake
2020-03-09 22:34 ` Alan Modra
2020-03-10 0:14 ` H.J. Lu
2020-03-09 14:34 ` Michael Matz
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