[Bug other/54182] New: enable -fvisibility=hidden

[Bug other/54182] New: enable -fvisibility=hidden

[wbrana at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54182

             Bug #: 54182
           Summary: enable -fvisibility=hidden
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: other
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: wbrana@gmail.com


-fvisibility=hidden could be enabled by default if -fPIC isn't used

[Bug other/54182] enable -fvisibility=hidden

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54182

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |build
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |WORKSFORME

--- Comment #1 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-08-06 08:35:25 UTC ---
>From your other PR I derive that you mean to include it in CFLAGS/BOOT_CFLAGS.
That's already effectively done if you disable plugins.

[Bug other/54182] enable -fvisibility=hidden

[wbrana at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54182

wbrana <wbrana at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |UNCONFIRMED
         Resolution|WORKSFORME                  |

--- Comment #2 from wbrana <wbrana at gmail dot com> 2012-08-06 08:52:14 UTC ---
I don't mean only flags used for building gcc, but -fvisibility=hidden should
be enabled if -O1/2/3/s is used and if -fPIC isn't used. How plugins have to
disabled? It shouldn't be needed.

[Bug other/54182] enable -fvisibility=hidden

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54182

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |INVALID

--- Comment #3 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-08-06 10:46:06 UTC ---
See the other bug.

[Bug other/54182] enable -fvisibility=hidden with -fPIE -pie

[wbrana at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54182

wbrana <wbrana at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |UNCONFIRMED
         Resolution|INVALID                     |
            Summary|enable -fvisibility=hidden  |enable -fvisibility=hidden
                   |                            |with -fPIE -pie

--- Comment #4 from wbrana <wbrana at gmail dot com> 2012-08-06 16:47:23 UTC ---
-fPIE -pie shouldn't disable -fvisibility=hidden

[Bug other/54182] -fPIE -pie shouldn't disable -fvisibility=hidden

[wbrana at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54182

wbrana <wbrana at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|build                       |
            Summary|enable -fvisibility=hidden  |-fPIE -pie shouldn't
                   |with -fPIE -pie             |disable -fvisibility=hidden

--- Comment #5 from wbrana <wbrana at gmail dot com> 2012-08-07 12:34:36 UTC ---
updated

[Bug other/54182] -fvisibility=hidden shouldn't be disabled with -fPIE -pie

[wbrana at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54182

wbrana <wbrana at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|-fPIE -pie shouldn't        |-fvisibility=hidden
                   |disable -fvisibility=hidden |shouldn't be disabled with
                   |                            |-fPIE -pie

--- Comment #6 from wbrana <wbrana at gmail dot com> 2012-08-10 12:31:08 UTC ---
updated

[Bug other/54182] -fvisibility=hidden shouldn't be disabled with -fPIE -pie

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54182

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |WAITING
   Last reconfirmed|                            |2012-08-10
     Ever Confirmed|0                           |1

--- Comment #7 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-08-10 13:30:02 UTC ---
-fPIE does not "disable" hidden visibility - why do you think so?  Please
provide a hint on what object code you want to generate for which testcase
and why that does not work currently like you want.

[Bug other/54182] -fvisibility=hidden shouldn't be disabled with -fPIE -pie

[wbrana at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54182

--- Comment #8 from wbrana <wbrana at gmail dot com> 2012-08-10 13:40:29 UTC ---
int func() {
        return random();
}

int main(){
        return func();
}

$ gcc-4.7.2 -O2 1.c -o 1
$ nm -CD ./1
                 w __gmon_start__
                 U __libc_start_main
                 U random

$ gcc-4.7.2 -O2 -fPIE -pie 1.c -o 1
$ nm -CD ./1
                 w _ITM_deregisterTMCloneTable
                 w _ITM_registerTMCloneTable
                 w _Jv_RegisterClasses
0000000000201040 B __bss_start
                 w __cxa_finalize
                 w __gmon_start__
00000000000008a0 T __libc_csu_fini
00000000000008b0 T __libc_csu_init
                 U __libc_start_main
0000000000201040 D _edata
0000000000201048 B _end
0000000000000760 T main
                 U random

[Bug other/54182] -fvisibility=hidden shouldn't be disabled with -fPIE -pie

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54182

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|WAITING                     |RESOLVED
                 CC|                            |jakub at gcc dot gnu.org
         Resolution|                            |INVALID

--- Comment #9 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-08-10 13:43:43 UTC ---
-fvisibility=hidden is only about the visibility of the symbols you define in
the code you are compiling, for controlling what you export or not out of a
binary, shared library or PIE, you need to tell what you want or don't want to
export to the linker.  -fvisibility=hidden is a compiler option, not a linker
option.

[Bug other/54182] -fvisibility=hidden shouldn't be disabled with -fPIE -pie

[wbrana at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54182

--- Comment #10 from wbrana <wbrana at gmail dot com> 2012-08-10 13:49:19 UTC ---
How can I tell linker to not export symbols?

[Bug other/54182] -fvisibility=hidden shouldn't be disabled with -fPIE -pie

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54182

--- Comment #11 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-08-10 16:53:54 UTC ---
You can use a linker version script.

http://sourceware.org/binutils/docs/ld/VERSION.html

[Bug other/54182] -fvisibility=hidden shouldn't be disabled with -fPIE -pie

[wbrana at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54182

--- Comment #12 from wbrana <wbrana at gmail dot com> 2012-08-10 17:27:02 UTC ---
Created attachment 27986
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=27986
bash compiled with -fPIE -pie -fvisibility=hidden

[Bug other/54182] -fvisibility=hidden shouldn't be disabled with -fPIE -pie

[wbrana at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54182

--- Comment #13 from wbrana <wbrana at gmail dot com> 2012-08-10 17:29:15 UTC ---
Created attachment 27987
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=27987
bash compiled with -fPIE -pie

[Bug other/54182] -fvisibility=hidden shouldn't be disabled with -fPIE -pie

[wbrana at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54182

wbrana <wbrana at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |REOPENED
         Resolution|INVALID                     |

--- Comment #14 from wbrana <wbrana at gmail dot com> 2012-08-10 17:39:27 UTC ---
-fvisibility=hidden is really disabled. Attached output from bash without
-fvisibility=hidden has 57 kB, but with -fvisibility=hidden only 11 kB.

Which compiler/linker flag except -fvisibility=hidden will make 11 kB output
from bash?

How exactly should I use linker version script to hide symbols in bash
executable or any other software?

[Bug other/54182] -fvisibility=hidden shouldn't be disabled with -fPIE -pie

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54182

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|REOPENED                    |RESOLVED
         Resolution|                            |INVALID

--- Comment #15 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-08-10 18:02:42 UTC ---
Bugzilla is not the right forum to learn how to use the linker.  Please read
its documentation.

[Bug other/54182] -fvisibility=hidden shouldn't be disabled with -fPIE -pie

[wbrana at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54182

wbrana <wbrana at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |REOPENED
         Resolution|INVALID                     |

--- Comment #16 from wbrana <wbrana at gmail dot com> 2012-08-10 18:17:02 UTC ---
-fvisibility=hidden exactly does what I need. Why it isn't enabled by default
with -fPIE -pie?

[Bug other/54182] -fvisibility=hidden shouldn't be disabled with -fPIE -pie

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54182

--- Comment #17 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-08-11 00:02:03 UTC ---
If it does what you need then use it.

[Bug other/54182] -fvisibility=hidden shouldn't be disabled with -fPIE -pie

[wbrana at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54182

--- Comment #18 from wbrana <wbrana at gmail dot com> 2012-08-11 07:01:18 UTC ---
I can use it, but other people don't have to know about this bug.

[Bug other/54182] -fvisibility=hidden shouldn't be disabled with -fPIE -pie

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54182

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|REOPENED                    |RESOLVED
         Resolution|                            |INVALID

--- Comment #19 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-08-11 07:32:52 UTC ---
It is not a bug and not everyone wants the same as you, e.g. you can't refer to
symbols in the PIE from plugins if you do.  When compiling PIE executables, you
shouldn't be using the -fPIC/-fpic flag, but -fPIE/-fpie instead, which works
similarly to -fvisibility=hidden in that references to those symbols are
cheaper (can use GOT/IP relative addressing on many architectures), but the
symbols are still exported.  Please stop reopening.

[Bug other/54182] -fvisibility=hidden shouldn't be disabled with -fPIE -pie

[wbrana at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54182

--- Comment #20 from wbrana <wbrana at gmail dot com> 2012-08-11 07:39:37 UTC ---
Why -fvisibility=hidden is enabled by default without -fPIE, but disabled with
-fPIE?

[Bug other/54182] -fvisibility=hidden shouldn't be disabled with -fPIE -pie

[wbrana at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54182

wbrana <wbrana at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |REOPENED
         Resolution|INVALID                     |

--- Comment #21 from wbrana <wbrana at gmail dot com> 2012-08-11 07:51:34 UTC ---
People who don't want -fvisibility=hidden should use -fvisibility=normal and
-fvisibility=hidden should be enabled by default.

[Bug other/54182] -fvisibility=hidden shouldn't be disabled with -fPIE -pie

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54182

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|REOPENED                    |RESOLVED
         Resolution|                            |WONTFIX

--- Comment #22 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-08-11 15:05:39 UTC ---
Again the defaults are this way because it has been this way since the
beginning of time.  It would be hard to change the defaults to hidden
visibility without changing a lot of program's makefiles.

[Bug other/54182] -fvisibility=hidden shouldn't be disabled with -fPIE -pie

[wbrana at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54182

--- Comment #23 from wbrana <wbrana at gmail dot com> 2012-08-11 15:17:04 UTC ---
Why lot of program's makefiles have to be changed?
If this change breaks some program, developers of that program will fix it.
You don't have to.
New versions of GCC always break many programs
see https://bugs.gentoo.org/show_bug.cgi?id=390247
This change will just another one of many changes.

[Bug other/54182] -fvisibility=hidden shouldn't be disabled with -fPIE -pie

[wbrana at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54182

wbrana <wbrana at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |REOPENED
         Resolution|WONTFIX                     |

--- Comment #24 from wbrana <wbrana at gmail dot com> 2012-08-11 15:37:47 UTC ---
I compiled many programs with -fPIE -pie -fvisibility=hidden and almost all
work fine. Very few broken ones could be easily fixed by adding
-fvisibility=normal.

[Bug middle-end/54182] -fvisibility=hidden shouldn't be disabled with -fPIE -pie

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54182

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |INVALID
             Status|REOPENED                    |RESOLVED

--- Comment #25 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Invalid as explained.