[Buildroot] [autobuild.buildroot.net] Build results for 2019-05-08

[Yann E. MORIN <yann.morin.1998@free.fr>]

Giulio, All,

On 2019-05-11 23:00 +0200, Giulio Benetti spake thusly:
> Hello Yann, All,
> 
> Il 09/05/2019 23:19, Giulio Benetti ha scritto:
> >>>       aarch64 |            python-numpy-1.16.3 | NOK | http://autobuild.buildroot.net/results/50f7f09a9f830cd7b94f8fc83c09fc3d39297d3d |
> >>
> >>/home/buildroot/autobuild/run/instance-2/output/host/bin/aarch64-linux-gnu-gcc /tmp/tmph865w02v/tmp/tmph865w02v/source.o -L/home/buildroot/autobuild/run/instance-2/output/host/aarch64-buildroot-linux-gnu/sysroot/usr/lib -lcblas -o /tmp/tmph865w02v/a.out
> >>/home/buildroot/autobuild/run/instance-2/output/host/aarch64-buildroot-linux-gnu/sysroot/usr/lib/libcblas.so: undefined reference to `scnrm2_'
> >>/home/buildroot/autobuild/run/instance-2/output/host/aarch64-buildroot-linux-gnu/sysroot/usr/lib/libcblas.so: undefined reference to `scasum_'
> >>collect2: error: ld returned 1 exit status
> >>/home/buildroot/autobuild/run/instance-2/output/host/bin/aarch64-linux-gnu-gcc /tmp/tmph865w02v/tmp/tmph865w02v/source.o -L/home/buildroot/autobuild/run/instance-2/output/host/aarch64-buildroot-linux-gnu/sysroot/usr/lib -lblas -o /tmp/tmph865w02v/a.out
> >>/tmp/tmph865w02v/tmp/tmph865w02v/source.o: In function `main':
> >>/tmp/tmph865w02v/source.c:6: undefined reference to `cblas_ddot'
> >>collect2: error: ld returned 1 exit status
> >>
> >>I'm not sure what's going on here. Sadly, Samuel who was maintaining
> >>python-numpy, is no longer active in Buildroot. Is there anyone else
> >>volunteering to have a look ?
> >
> >I can try to work this out.
> >
> 
> As spoken in IRC this builds correctly with every Docker in Adam Duskett:
> https://github.com/aduskett/buildroot-docker-devel
> 
> included Ubuntu 14.04(Trusty), the same as Yann's Autobuilder.
> 
> I'm waiting for Yann to report if it works for him too or not.

Here is a quick summary of Giulio's and my findings:

Usign the configuration from the failed autobuild job:

  - make clean; make python-numpy    --> builds OK

  - make clean; make   --> fails to build

The root cause is a hidden dependency on lapack. When lapack is build
before python-numpy (which is highly possible, because of alphabetical
ordering), then python-numpy detects it and fails to build properly in
this case.

So, I can see two solutions:

  - add an explicit, conditional dependency on lapack, and fix the
    build,

  - explicitly tell python-numpy to never use lapack.

Obviously, the first would be preferred, but it's probably non-trivial.

Regards,
Yann E. MORIN.

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