Re: [Qemu-devel] [PATCH, RFC] ld flag --warn-common

[Kirill A. Shutemov]

On Mon, Sep 22, 2008 at 07:24:27PM +0300, Blue Swirl wrote:
> On 9/22/08, Kirill A. Shutemov <address@hidden> wrote:
> > On Sat, Sep 20, 2008 at 10:49:36AM +0300, Blue Swirl wrote:
> >  > On 9/19/08, Kirill A. Shutemov <address@hidden> wrote:
> >  > > On Sun, Sep 07, 2008 at 11:24:37AM +0300, Blue Swirl wrote:
> >  > >  > Hi,
> >  > >  >
> >  > >  > These trivial patches enable linker flag --warn-common and fix the
> >  > >  > warnings caused by enabling the flag.
> >  > >
> >  > >
> >  > > This flag cause a lot of warning on my machine, even with trivial 
> > program.
> >  > >
> >  > >  $ cat 1.c
> >  > >  #include <stdio.h>
> >  > >
> >  > >  int main()
> >  > >  {
> >  > >         printf("test\n");
> >  > >         return 0;
> >  > >  }
> >  > >  $ gcc -Wl,--warn-common -static 1.c
> >  > >  
> > /usr/lib64/gcc/x86_64-alt-linux/4.1.2/../../../../lib64/libc.a(strtoul.o): 
> > warning: multiple common of `_nl_category_name_idxs'
> >  > >  
> > /usr/lib64/gcc/x86_64-alt-linux/4.1.2/../../../../lib64/libc.a(strtol.o): 
> > warning: previous common is here
> >  > >  
> > /usr/lib64/gcc/x86_64-alt-linux/4.1.2/../../../../lib64/libc.a(strtol_l.o): 
> > warning: multiple common of `_nl_category_name_idxs'
> >  > >  
> > /usr/lib64/gcc/x86_64-alt-linux/4.1.2/../../../../lib64/libc.a(strtol.o): 
> > warning: previous common is here
> >  > >  
> > /usr/lib64/gcc/x86_64-alt-linux/4.1.2/../../../../lib64/libc.a(strtoul_l.o):
> >  warning: multiple common of `_nl_category_name_idxs'
> >  > >  
> > /usr/lib64/gcc/x86_64-alt-linux/4.1.2/../../../../lib64/libc.a(strtol.o): 
> > warning: previous common is here
> >  > >  
> > /usr/lib64/gcc/x86_64-alt-linux/4.1.2/../../../../lib64/libc.a(vfprintf.o): 
> > warning: multiple common of `_nl_category_name_idxs'
> >  > >  
> > /usr/lib64/gcc/x86_64-alt-linux/4.1.2/../../../../lib64/libc.a(strtol.o): 
> > warning: previous common is here
> >  > >
> >  > >  ...and so on.
> >  > >
> >  > >
> >  > >  Is it problem with my toolchain? What is your testing environment?
> >  >
> >  > I get no warnings for Qemu build on Debian i386, amd64
> >  > (stable/unstable), Sparc32, Sparc64 or on OpenBSD/Sparc64. Your
> >  > program produces one warning on Debian stable (all hosts except no
> >  > warnings on arm), no warnings on Debian amd64 unstable or OpenBSD.
> >
> >
> > I've got a lot of warnings on ALT Linux x86_64 and Ubuntu x86_64. Both
> >  with gcc 4.1.2. Are you sure that you test static build?
> 
> $ gcc -Wl,--warn-common -static main.c
> /usr/lib/gcc/x86_64-linux-gnu/4.1.2/../../../../lib64/libc.a(dl-open.o):
> warning: definition of `_dl_tls_static_size' overriding common
> /usr/lib/gcc/x86_64-linux-gnu/4.1.2/../../../../lib64/libc.a(libc-tls.o):
> warning: common is here
> $ cat main.c
> #include <stdio.h>
> 
> int main()
> {
>        printf("test\n");
>        return 0;
> }

I think --warn-common shouldn't be added to LDFLAGS, when we build static
qemu.

-- 
Regards,  Kirill A. Shutemov
 + Belarus, Minsk
 + ALT Linux Team, http://www.altlinux.com/

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