[Pixman] [PATCH] configure: add options to disable demos and tests

[Thomas Petazzoni]

Hello,

On Wed, 20 Jan 2016 09:27:46 +0200, Siarhei Siamashka wrote:

> Thanks for this patch. Though if building (and using) pixman on
> such platforms is wanted, then a much better solution would be to
> update the problematic tests and make them compile. Skipping some
> sub-tests is better than having no tests at all. I also remember
> your patch for FE_DIVBYZERO from a few months ago:
> 
>     http://lists.freedesktop.org/archives/pixman/2015-September/004019.html
> 
> Is it still the same Microblaze or Nios2 architecture that is causing
> problems for you?

Yes, it is. Other architectures might be affected because the <fenv.h>
implementation in uClibc is not complete for all architectures.

> While adding new configure options just adds functionality and
> preserves the existing behavior, I don't feel very happy about
> the fact that this provides an easy way to ignore problems instead
> of fixing them. It would be really great is somebody tried to run
> the pixman test suite ("make check") on these architectures at
> least once.
> 
> Encountering compiler bugs is unfortunately a regular occurrence
> for pixman. For example, not so long ago, GCC 4.9 miscompiled
> pixman on ARM (fortunately, the broken code was in the test suite
> itself and not in the pixman library):
> 
>     https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64172
> 
> And even just a few days ago, pixman was one of the victims during
> a GCC 6 snapshot test (an easy to notice ICE during a distro test
> rebuild):
> 
>     https://gcc.gnu.org/ml/gcc/2016-01/msg00101.html
>     https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66856
> 
> What I'm trying to say is that there had been many compiler bugs
> affecting pixman during the last few years. Now you are dealing
> with uncommon architectures, and the compilers there are probably
> even less mature than GCC on x86 / arm / powerpc.

I agree, but those options also allow to skip building things that
won't be used, even if they actually build properly. On ARM, x86,
PowerPC and other "mainstream" architectures, the demos and tests build
fine, but they are not used at all by Buildroot, so it's just spending
time building things that aren't necessary.

So even if those tests and demos were building for all architectures,
it would still be useful to have a way to *not* build them.

But I'll have a look at re-enabling the building of the pixman tests in
Buildroot. Now that the FE_* things are disabled in the tests when not
available (after commit 4297e9058d252cac653723fe0b1bee559fbac3a4).

Thanks!

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com