Re: [PATCH] Makerules: pass CFLAGS when building .S files, BZ #23273

[Florian Weimer <fweimer at redhat dot com>]

On 06/11/2018 03:18 PM, Sergei Trofimovich wrote:
> On Mon, 11 Jun 2018 14:50:24 +0200
> Florian Weimer <fweimer@redhat.com> wrote:
>
> > On 06/11/2018 02:35 PM, Sergei Trofimovich wrote:
> > > On Mon, 11 Jun 2018 08:17:37 -0300
> > > Adhemerval Zanella <adhemerval.zanella@linaro.org> wrote:
> > >    
> > > > On 11/06/2018 07:46, Florian Weimer wrote:
> > > > > On 06/11/2018 12:28 PM, Sergei Trofimovich wrote:
> > > > > > When glibc is built on armv7 with CFLAGS="-pipe -march=armv7-a -O2 -mfpu=neon"
> > > > > > rtld fails to link due to missing memcpy symbol.
> > > > > >
> > > > > > This happens because .c files are built with -mfpu=neon flag but .S/.s files
> > > > > > are built without it. Among other things -mfpu=neon defines __ARM_NEON__.
> > > > > >
> > > > > > To fix this mismatch CFLAGS should be passed consistently to .c and .S files.
> > > > >
> > > > > Please check if you can fix this by putting the architecture selection flags into the CC and CXX variables when invoking configure.
> > >
> > > I'm not sure just adding an arch flag is enough:
> > >       https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/arm/armv7/multiarch/memcpy_neon.S;h=1a8d8bbe9e128618105be0652de42a34fbc52d73;hb=HEAD
> > >      ...
> > >      2 #ifndef __ARM_NEON__
> > >      3 # define memcpy __memcpy_neon
> > > Here memcpy_neon.S explicitly supports both neon-enabled and disabled flags.
> >
> > Does this mean your proposed patch fails to address the issue, too?
>
> My proposed patch fixes ld.so linkage (and ld.so seems to work).

Yes, but what about using CC/CXX setting at configure time to achieve 
the same effect?

Thanks,
Florian