[Pixman] [PATCH 1/2] autotools: use custom build rule to build iwMMXt code

[Siarhei Siamashka]

On Sat, 27 Jul 2013 20:35:57 +0300
Siarhei Siamashka <siarhei.siamashka at gmail.com> wrote:

> On Sat, 27 Jul 2013 15:02:42 +0200
> Julien Cristau <jcristau at debian.org> wrote:
> 
> > Hi Matt,
> > 
> > On Wed, May 30, 2012 at 16:46:38 -0400, Matt Turner wrote:
> > 
> > > gcc has no sane way of enabling iwmmxt code generation, like -msse for
> > > SSE, so you have to use -march=iwmmxt{,2}. User CFLAGS are placed after
> > > -march=iwmmxt and override the march value, so we have to use a custom
> > > build rule to order the CFLAGS such that pixman-mmx.c will be built with
> > > the necessary CFLAGS.
> > > ---
> > >  configure.ac       |    2 +-
> > >  pixman/Makefile.am |   18 +++++++++++++-----
> > >  2 files changed, 14 insertions(+), 6 deletions(-)
> > > 
> > This custom rule seems to have dependency issues, see
> > https://buildd.debian.org/status/fetch.php?pkg=pixman&arch=armel&ver=0.30.0-1&stamp=1374857136

[...]

> Is there a pre-built debian armel rootfs available somewhere for a
> quick test?

Without having any reasonable means to reproduce the problem, I can
only suggest to try changing the build rule to list the dependencies
explicitly instead of relying on the "-MD" option. And maybe even
try to simplify the build rule to strip out the intermediate library
generation and do it in a really minimalistic way:

pixman-iwmmxt.o: pixman-mmx.c <a_bunch_of_header_files>
    gcc -O3 -march=iwmmxt -o pixman-iwmmxt.o pixman-mmx.c

libpixman_1_la_LDADD += pixman-iwmmxt.o

That's totally untested though. But just a few trial and error
experiments on a failing system would probably provide some
insights about what's wrong there.

-- 
Best regards,
Siarhei Siamashka