amd64/127640: GCC will not build shared libraries with -fprofile-generate on amd64

[John Baldwin]

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 at 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