From: "H.J. Lu" <hjl.tools@gmail.com>
To: Alan Modra <amodra@gmail.com>
Cc: Binutils <binutils@sourceware.org>
Subject: Re: [PATCH] LTO: Ignore undefined symbols without relocation
Date: Thu, 30 Jul 2020 04:51:35 -0700 [thread overview]
Message-ID: <CAMe9rOq=J-0Ms=usypC-rAZQtmB4bjgo0bv8CDV4ooaOdAeFsg@mail.gmail.com> (raw)
In-Reply-To: <20200730093214.GT9601@bubble.grove.modra.org>
On Thu, Jul 30, 2020 at 2:32 AM Alan Modra <amodra@gmail.com> wrote:
>
> On Wed, Jul 29, 2020 at 03:22:58PM -0700, H.J. Lu via Binutils wrote:
> > Normally an undefined symbol is treated as a reference. Linker will
> > try to satisfy the reference. This feature is used to bring a symbol
> > definition into output without explicit relocation. If there is no
> > definition nor relocation, linker will remove undefined symbol from
> > symbol table in output (PR ld/4317). But GCC 10 LTO may generate
> > separate debug info files which contain undefined symbols without
> > relocations:
>
> Surely this is just a gcc bug? We search libraries again after
> loading the LTO output, so one would expect that undefined symbols
> satisfied by an archive (or as-needed shared library) would lead to
> extra files being linked.
>
> I'd like to better understand just how this problem occurs though. As
> it is, I suspect there might be something else going on here, for
> example, ranlib being run without a plugin when building the archives.
A testcase is on pr96385 branch at:
https://gitlab.com/x86-gcc/gcc-bugs
--
H.J.
next prev parent reply other threads:[~2020-07-30 11:52 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-29 22:22 H.J. Lu
2020-07-30 9:32 ` Alan Modra
2020-07-30 10:39 ` [PATCH] elf: Add sym_cache to elf_link_hash_table H.J. Lu
2020-07-30 11:51 ` H.J. Lu [this message]
2020-07-31 8:12 ` [PATCH] LTO: Ignore undefined symbols without relocation Alan Modra
2020-07-31 9:51 ` Nick Clifton
2020-07-31 10:07 ` Nick Clifton
2020-07-31 11:02 ` Alan Modra
2020-07-31 11:43 ` H.J. Lu
2020-07-31 15:47 ` V2 " H.J. Lu
2020-08-03 7:26 ` Alan Modra
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