[Mesa-dev] [RFC 6/8] mesa: remove support for GCC older than 4.1.0

[Jonathan Gray]

On Wed, Dec 17, 2014 at 07:39:21AM -0800, Matt Turner wrote:
> On Wed, Dec 17, 2014 at 7:28 AM, Jonathan Gray <jsg at jsg.id.au> wrote:
> > On Thu, Dec 18, 2014 at 12:26:10AM +1100, Timothy Arceri wrote:
> >> On Tue, 2014-12-16 at 22:58 -0800, Vinson Lee wrote:
> >> > On Mon, Dec 15, 2014 at 6:23 PM, Jonathan Gray <jsg at jsg.id.au> wrote:
> >> > > On Sat, Dec 13, 2014 at 09:09:27PM +1100, Timothy Arceri wrote:
> >> > >> On Fri, 2014-12-12 at 07:01 -0600, kallisti5 wrote:
> >> > >> > On 2014-12-12 05:46, Timothy Arceri wrote:
> >> > >> > > Signed-off-by: Timothy Arceri <t_arceri at yahoo.com.au>
> >> > >> > > ---
> >> > >> > >  src/mesa/main/compiler.h | 2 +-
> >> > >> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> >> > >> > >
> >> > >> > > diff --git a/src/mesa/main/compiler.h b/src/mesa/main/compiler.h
> >> > >> > > index 34671dc..cdc843d 100644
> >> > >> > > --- a/src/mesa/main/compiler.h
> >> > >> > > +++ b/src/mesa/main/compiler.h
> >> > >> > > @@ -122,7 +122,7 @@ extern "C" {
> >> > >> > >   * inline a static function that we later use in an alias. - ajax
> >> > >> > >   */
> >> > >> > >  #ifndef PUBLIC
> >> > >> > > -#  if (defined(__GNUC__) && __GNUC__ >= 4) || (defined(__SUNPRO_C) &&
> >> > >> > > (__SUNPRO_C >= 0x590))
> >> > >> > > +#  if defined(__GNUC__) || (defined(__SUNPRO_C) && (__SUNPRO_C >=
> >> > >> > > 0x590))
> >> > >> > >  #    define PUBLIC __attribute__((visibility("default")))
> >> > >> > >  #    define USED __attribute__((used))
> >> > >> > >  #  else
> >> > >> >
> >> > >> > Why not also drop the SUNPRO_C version check?
> >> > >> >
> >> > >> > #  if defined(__GNUC__) || defined(__SUNPRO_C)
> >> > >> >
> >> > >> > I downloaded SunStudio 12 (circa 2007) and __SUNPRO_C is set to 0x590.
> >> > >> > If we drop support for GCC 4.1 (2007), might as well drop older sun
> >> > >> > compilers.
> >> > >>
> >> > >>
> >> > >> The series is dropping support for GCC 4.0. 4.1 is shipped with Redhat
> >> > >> Enterprise Linux 5 which is still in support so I've set that as the
> >> > >> minimum version.
> >> > >
> >> > > It is worth pointing out OpenBSD ships a patched GCC 4.2.1 as the base
> >> > > compiler as that was the last GPLv2 licensed version.  Not relevant this
> >> > > time, perhaps it will be next time.
> >> > > _______________________________________________
> >> > > mesa-dev mailing list
> >> > > mesa-dev at lists.freedesktop.org
> >> > > http://lists.freedesktop.org/mailman/listinfo/mesa-dev
> >> >
> >> >
> >> > Latest master doesn't build with GCC 4.1.
> >> >
> >> > glsl/ir_uniform.h:45: error: use of enum ???gl_uniform_driver_format???
> >> > without previous declaration
> >>
> >> My reasoning for using 4.1 seems to be flawed as RHEL 5 comes with
> >> autoconf 2.59 by default and current Mesa requires 2.60. Maybe bumping
> >> GCC to 4.2 would be better. I assume the above issue doesn't happen on
> >> 4.2 since OpenBSD uses it?
> >
> > I don't see that error with master here.
> >
> > The problem seems to be the use of an attribute on the enum which going
> > by https://gcc.gnu.org/gcc-4.2/changes.html is only supported after 4.2.0?
> 
> Indeed, and that code has been in place since June and no one has
> complained as far as I can tell.
> 
> I'm okay with bumping the minimum to 4.2. We're already using
> __attribute__((packed)) on enums in a number of places in the i965
> driver.

i965 also requires the GCC extension of binary integer constants which
was introduced in GCC 4.3.  I backported the GPLv2 patch in GCC PR 23479
for that to OpenBSD's 4.2.1.  I know at least FreeBSD did that as well.