V2 [PATCH] Mark __libc_freeres_fn as used [# 27002]

Message ID CAMe9rOpSPa3=cT=xk0mxeS8afyXu005+KO3dgQA1hwC_4vBGKw@mail.gmail.com
State Committed
Headers
Series V2 [PATCH] Mark __libc_freeres_fn as used [# 27002] |

Commit Message

H.J. Lu Dec. 11, 2020, 10:22 p.m. UTC
  On Thu, Dec 3, 2020 at 5:36 AM Florian Weimer <fweimer@redhat.com> wrote:
>
> * H. J. Lu:
>
> > GCC 11 is changed to place the used symbol in SHF_GNU_RETAIN section to
> > support --gc-sections.  If you believe it is wrong, please file a GCC bug.
>
> Okay, I filed: <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98121>
>

Independent of the GCC issue, __libc_freeres_fn should have the
used attribute.  OK for master?
  

Comments

Florian Weimer Dec. 16, 2020, 10:30 a.m. UTC | #1
* H. J. Lu:

> On Thu, Dec 3, 2020 at 5:36 AM Florian Weimer <fweimer@redhat.com> wrote:
>>
>> * H. J. Lu:
>>
>> > GCC 11 is changed to place the used symbol in SHF_GNU_RETAIN section to
>> > support --gc-sections.  If you believe it is wrong, please file a GCC bug.
>>
>> Okay, I filed: <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98121>
>>
>
> Independent of the GCC issue, __libc_freeres_fn should have the
> used attribute.  OK for master?

Looks okay to me.  Thanks.

Florian
  

Patch

From afb70a56cd57f0900f7a0b61e51500da2cdf1f4e Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Wed, 2 Dec 2020 14:26:28 -0800
Subject: [PATCH] Mark __libc_freeres_fn as used [BZ #27002]
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

GCC 11 with

commit 6fbec038f7a7ddf29f074943611b53210d17c40c
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Mon Feb 3 11:55:43 2020 -0800

    Use SHF_GNU_RETAIN to preserve symbol definitions

places used symbols in SECTION_RETAIN sections if assembler supports it.
Mark __libc_freeres_fn as used to avoid

gconv_dl.c: In function ‘free_mem’:
gconv_dl.c:191:1: error: ‘do_release_all’ without ‘used’ attribute and ‘free_mem’ with ‘used’ attribute are placed in a section with the same name [-Werror=attributes]
  191 | do_release_all (void *nodep)
      | ^~~~~~~~~~~~~~
In file included from <command-line>:
gconv_dl.c:202:18: note: ‘free_mem’ was declared here
  202 | libc_freeres_fn (free_mem)
      |                  ^~~~~~~~
./../include/libc-symbols.h:316:15: note: in definition of macro ‘libc_freeres_fn’
  316 |   static void name (void)
      |               ^~~~
cc1: all warnings being treated as errors
---
 include/libc-symbols.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/libc-symbols.h b/include/libc-symbols.h
index 154a73b5e5..f06ce3053a 100644
--- a/include/libc-symbols.h
+++ b/include/libc-symbols.h
@@ -307,7 +307,7 @@  for linking")
 
 /* Resource freeing functions from libc.so go in this section.  */
 #define __libc_freeres_fn_section \
-  __attribute__ ((section ("__libc_freeres_fn")))
+  __attribute__ ((__used__, section ("__libc_freeres_fn")))
 
 /* Resource freeing functions for libc.so.  */
 #define libc_freeres_fn(name) \
-- 
2.29.2