[Mesa-dev] [PATCH 2/2] configure.ac: refuse to build r300g without LLVM

[Jose Fonseca]

----- Original Message -----
> On Thu, Apr 21, 2011 at 11:39 AM, Marek Olšák <maraeo at gmail.com>
> wrote:
> > ---
> >  configure.ac |    5 +++++
> >  1 files changed, 5 insertions(+), 0 deletions(-)
> >
> > diff --git a/configure.ac b/configure.ac
> > index 8e9f73f..84a75c4 100644
> > --- a/configure.ac
> > +++ b/configure.ac
> > @@ -1778,6 +1778,11 @@ AC_ARG_ENABLE([gallium-r300],
> >         [build gallium r300 @<:@default=disabled@:>@])],
> >     [enable_gallium_r300="$enableval"],
> >     [enable_gallium_r300=auto])
> > +if test "x$enable_gallium_r300" != xno; then
> > +    if test "x$MESA_LLVM" = x0; then
> > +        AC_MSG_ERROR([LLVM is required to build r300g])
> > +    fi
> > +fi
> >  if test "x$enable_gallium_r300" = xauto; then
> >     GALLIUM_DRIVERS_DIRS="$GALLIUM_DRIVERS_DIRS r300"
> >     gallium_check_st "radeon/drm" "dri-r300"
> > --
> > 1.7.4.1
> 
> How does this affect architectures on which r300g works but don't
> have
> LLVM JIT support? See [1]. (I'm assuming that LLVMpipe requires JIT
> support in LLVM). r300g works on Alpha, SPARC, and probably others
> that don't have JIT support.
> 
> I think the purpose of this patch is to simply prevent downstream
> packagers from screwing up SWTCL users, but on, say, Alpha and SPARC,
> I don't think SWTCL cards are possible. Does LLVMpipe in addition to
> r300g do any good for HWTCL cards?

The Mesa state tracker uses SWTNL for GL selection/feedback regardless of the driver. Some SPECviewperf viewsets and CAD apps use it. So using LLVM speeds up selection/feedback for all gallium drivers.

We have only tested LLVM with x86/x86_64. So indeed, using it/requiring it on other platforms is not advisable.

Jose