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

[Siarhei Siamashka]

On Sun, 17 Jan 2016 15:31:47 +0100
Thomas Petazzoni <thomas.petazzoni at free-electrons.com> wrote:

> On certain architectures, the functionality of <fenv.h> may not be
> available, which prevents building the pixman tests. In order to still
> allow building pixman easily on such platforms, this commit adds two
> new configure options, --disable-testprogs and --disable-demos, which
> can be used to disable building the test and demo programs
> respectively.

Hello Thomas,

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?

> Of course, by default, tests and demo programs continue to be built,
> so that the existing behavior is preserved.
> 
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni at free-electrons.com>

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.

-- 
Best regards,
Siarhei Siamashka