[Bug lto/43659] -flto doesn't remember -fPIC

[Bug lto/43659] -flto doesn't remember -fPIC

[devurandom at gmx dot net]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43659

devurandom at gmx dot net changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |devurandom at gmx dot net

--- Comment #3 from devurandom at gmx dot net 2010-11-30 10:05:17 UTC ---
The issue seems to still exist in 4.5.1. Does it have something to do with bug
#40546?

On Gentoo, at least following packages are affected:
app-arch/bzip2-1.0.6-r1, dev-libs/libebml-1.0.0, media-libs/jpeg-6b-r9,
media-libs/openjpeg-1.3-r3, media-sound/gsm-1.0.13, net-libs/libsrtp-1.4.4-r1

[Bug lto/43659] -flto doesn't remember -fPIC

[hubicka at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43659

Jan Hubicka <hubicka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2011.01.08 19:54:57
                 CC|                            |hubicka at gcc dot gnu.org
      Known to work|                            |4.6.0
     Ever Confirmed|0                           |1

--- Comment #4 from Jan Hubicka <hubicka at gcc dot gnu.org> 2011-01-08 19:54:57 UTC ---
This was fixed on mainline by patch of mine
http://gcc.gnu.org/ml/gcc-patches/2011-01/msg00210.html
perhaps it can be backported.

[Bug lto/43659] -flto doesn't remember -fPIC

[rguenth at gcc dot gnu dot org]

------- Comment #2 from rguenth at gcc dot gnu dot org  2010-04-06 08:57 -------
GCC has code to do exactly this.  Somebody needs to debug why it doesn't work.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43659

[Bug lto/43659] -flto doesn't remember -fPIC

[pinskia at gmail dot com]

------- Comment #1 from pinskia at gmail dot com  2010-04-06 03:01 -------
Subject: Re:   New: -flto doesn't remember -fPIC

This is done on purpose. The -fpic is needed on the link line too.  
This is a bug in libtool.

Sent from my iPhone

On Apr 5, 2010, at 6:47 PM, "debian-gcc at lists dot debian dot org"
<gcc-bugzilla@gcc.gnu.org 
 > wrote:

> [forwarded from http://bugs.debian.org/524176]
>
>  Matthias
>
> gcc-4.5 with -flto doesn't work with -fPIC properly.
>
> Simple testcase:
> int entry(int a)
> {
>    return bar(a)+1;
> }
>
> int bar(int a)
> {
>    return a+4;
> }
>
> $ gcc-4.5 foo1.c -flto -fPIC -DPIC -c
> $ gcc-4.5 foo2.c -flto -fPIC -DPIC -c
> $ gcc-4.5 foo1.o foo2.o -flto -shared
> /usr/bin/ld: /tmp/ccmA7RCK.lto.o: relocation R_X86_64_PC32 against  
> symbol `bar'
> can not be used when making a shared object; recompile with -fPIC
> /usr/bin/ld: final link failed: Bad value
> collect2: ld returned 1 exit status
>
> This works however:
> $ gcc-4.5 foo1.o foo2.o -flto -shared -fPIC
>
> Now -fPIC is something libtool automatically adds, and I it doesn't  
> add it at
> linktime (perhaps other build systems don't either).
> Could gcc's -flto see that all .o files involved in the link are - 
> fPIC... and
> make the resulting file -fPIC too?
> Or at least it should see the -shared in the linker line, and  
> automatically use
> -fPIC when -flto is used.
>
>
> -- 
>           Summary: -flto doesn't remember -fPIC
>           Product: gcc
>           Version: 4.5.0
>            Status: UNCONFIRMED
>          Severity: normal
>          Priority: P3
>         Component: lto
>        AssignedTo: unassigned at gcc dot gnu dot org
>        ReportedBy: debian-gcc at lists dot debian dot org
>
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43659
>


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43659