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Re: [PATCH] Remove debug/stack_chk_fail_local.c [BZ #21740]
On 18 Jul 2017, H. J. Lu uttered the following:
> From 47d95763a35fbc83ac871b10fc59f9eca1ef0a40 Mon Sep 17 00:00:00 2001
> From: "H.J. Lu" <hjl.tools@gmail.com>
> Date: Sun, 9 Jul 2017 08:39:17 -0700
> Subject: [PATCH] Don't add stack_chk_fail_local.o to libc.a [BZ #21740]
>
> commit 524a8ef2ad76af8ac049293d993a1856b0d888fb
> Author: Nick Alcock <nick.alcock@oracle.com>
> Date: Mon Dec 26 10:08:57 2016 +0100
>
> PLT avoidance for __stack_chk_fail [BZ #7065]
>
> Add a hidden __stack_chk_fail_local alias to libc.so,
> and make sure that on targets which use __stack_chk_fail,
> this does not introduce a local PLT reference into libc.so.
>
> which unconditionally added
>
> strong_alias (__stack_chk_fail, __stack_chk_fail_local)
>
> defines __stack_chk_fail_local as an alias of __stack_chk_fail in libc.a.
> There is no need to add stack_chk_fail_local.o to libc.a. We only need
> to add stack_chk_fail_local.oS to libc_nonshared.a.
Completely agreed -- we only need the _local alias because of internal
calls within the *shared* libc and related objects (in all of which the
symbol is hidden). The nonshared libc just calls __stack_chk_fail
directly and should not reference stack_chk_fail_local at all, and
nothing else should have undefined references to it because the only
objects that presently reference it should also contain a definition of
it.
--
NULL && (void)