Date: Fri, 26 Sep 2008 14:10:05 GMT From: John Baldwin <jhb@freebsd.org> To: freebsd-amd64@FreeBSD.org Subject: Re: amd64/127640: GCC will not build shared libraries with -fprofile-generate on amd64 Message-ID: <200809261410.m8QEA5YX035451@freefall.freebsd.org>
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The following reply was made to PR amd64/127640; it has been noted by GNATS.
From: John Baldwin <jhb@freebsd.org>
To: freebsd-amd64@freebsd.org
Cc: Jonathan Briggs <zlynx@acm.org>, freebsd-gnats-submit@freebsd.org
Subject: Re: amd64/127640: GCC will not build shared libraries with -fprofile-generate on amd64
Date: Fri, 26 Sep 2008 10:01:43 -0400
On Thursday 25 September 2008 04:50:43 pm Jonathan Briggs wrote:
>
> >Number: 127640
> >Category: amd64
> >Synopsis: GCC will not build shared libraries with -fprofile-generate
on amd64
> >Confidential: no
> >Severity: non-critical
> >Priority: low
> >Responsible: freebsd-amd64
> >State: open
> >Quarter:
> >Keywords:
> >Date-Required:
> >Class: sw-bug
> >Submitter-Id: current-users
> >Arrival-Date: Thu Sep 25 21:00:03 UTC 2008
> >Closed-Date:
> >Last-Modified:
> >Originator: Jonathan Briggs
> >Release: 7.0-RELEASE
> >Organization:
> >Environment:
> FreeBSD freebsd64 7.0-RELEASE FreeBSD 7.0-RELEASE #0: Sun Feb 24 10:35:36
UTC 2008 root@driscoll.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC
amd64
>
> >Description:
> I was porting a specialized database library to FreeBSD and the build failed
with this error:
>
> /usr/bin/ld: /usr/lib/libgcov.a(_gcov_merge_add.o): relocation R_X86_64_32
can not be used when making a shared object; recompile with -fPIC
> /usr/lib/libgcov.a: could not read symbols: Bad value
>
> The library uses -fprofile-generate, runs a test set, then rebuilds
with -fprofile-use. It's worth a few ms per lookup.
>
> Also, this builds very well on i386 FreeBSD 7.0 and on many varieties of
Linux and their GCC builds (Debian ia64, Gentoo amd64, CentOS 5.2, Fedora 5,
8, 9).
>
> I can work around the problem by just not doing a profile build.
> >How-To-Repeat:
> Put the following in a shell script:
>
> #!/bin/sh
> cat <<EOF |
> #include <stdio.h>
>
> int counter(int count)
> {
> int i;
>
> for(i=0; i<count; i++) {
> printf("loop %d\n", i);
> }
> return i;
> }
> EOF
> gcc -O2 -shared -fprofile-generate -fPIC -o t1.so -x c -
What if you add -fPIC as the message suggests?
--
John Baldwin
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