Re: [PATCH] S/390: STT_GNU_IFUNC support

[Mike Frysinger <vapier at gentoo dot org>]

On Tuesday 03 July 2012 06:19:44 Andreas Krebbel wrote:
> On 07/02/2012 04:21 PM, Andreas Jaeger wrote:
> > On Monday, July 02, 2012 15:52:49 Andreas Krebbel wrote:
> >> On Mon, Jul 02, 2012 at 03:20:30PM +0200, Andreas Jaeger wrote:
> >>> So, do you want to add a configure test and only enable the IFUNC
> >>> support with new binutils? Or how do you want to handle the
> >>> requirement?
> >> 
> >> I'll add a configure check when it is clear which Binutils version
> >> will include the support.
> > 
> > I suggest to check for the feature, not for the version, the configure
> > file already has support for this, so this might be enough:
> > AC_CACHE_CHECK([for assembler gnu_indirect_function symbol type
> > support],
> >                libc_cv_asm_gnu_indirect_function, [dnl
> > cat > conftest.s <<EOF
> > .type foo,%gnu_indirect_function
> > EOF
> > if ${CC-cc} -c $ASFLAGS conftest.s 1>&AS_MESSAGE_LOG_FD
> > 2>&AS_MESSAGE_LOG_FD;
> > then
> >   libc_cv_asm_gnu_indirect_function=yes
> > else
> >   libc_cv_asm_gnu_indirect_function=no
> > fi
> > rm -f conftest*])
> 
> This only checks whether the assembler supports gnu_indirect_function as
> symbol type not whether the linker actually handles IFUNC symbols for the
> target.

yes, this has bit us with sparc already for example.  people have a new enough 
binutils that supports ifunc type, but the backend doesn't support it, so we 
get weird build errors.  if we could get a more extensive test here, that'd be 
awesome.
-mike

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