Re: [qemu-s390x] [Qemu-devel] [PATCH] configure: Only build the s390-ccw bios if the compiler supports -march=z900

[Peter Maydell]

On Mon, 14 Jan 2019 at 12:24, Thomas Huth <address@hidden> wrote:
>
> We want to build our s390-ccw bios with -march=z900 so that it also
> works with the oldest s390x CPU that we support with TCG. However,
> Clang on s390x does not support -march=z900 anymore, so we can not
> use this compiler to build the s390-ccw bios. Thus add a proper test
> to the configure script to see whether the compiler is usable.
>
> Signed-off-by: Thomas Huth <address@hidden>
> ---
>  configure | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/configure b/configure
> index 05b7e85..df34974 100755
> --- a/configure
> +++ b/configure
> @@ -5906,7 +5906,10 @@ if test "$cpu" = "ppc64" -a "$targetos" != "Darwin" ; 
> then
>  fi
>
>  if test "$cpu" = "s390x" ; then
> -  roms="$roms s390-ccw"
> +  # Only build the s390-ccw bios if the compiler supports -march=z900
> +  if "$cc" -dumpspecs 2>/dev/null | grep -q "march=z900"; then
> +    roms="$roms s390-ccw"
> +  fi
>  fi

clang doesn't support -dumpspecs at all, so you're implicitly
saying "not clang" by doing the check this way... If you
want to check "does the compiler supoprt -march=z900" why
not do a test compile with that in the compile flags ?

   write_c_skeleton
   if compile_prog "-march=z900" ""; then
       roms="$roms s390-ccw"
   fi

?

(untested)

thanks
-- PMM