[Buildroot] Analysis of build results for 2016-05-16

[Thomas Petazzoni <thomas.petazzoni@free-electrons.com>]

Hello,

On Tue, 17 May 2016 17:13:50 +0200, gwenhael.goavec wrote:

> > >       x86_64 |               gnuradio-3.7.9.1 | NOK |
> > > http://autobuild.buildroot.net/results/714019031fb8c8f70c1838aa18e4ec1e4abf165e/    
> > 
> > internal compiler error: Segmentation fault
> > 
> > Gwenhael, can you look into this problem?
> >   
> I'm looking into this problem :
> - Fails with a binary toolchain (gcc-4.7.2);
> - Works with a toolchain generated by buildroot (same options but
>   4.8.5 and 4.9.3).
> I need to see if it's due to the gcc version or something else.

Potentially seems like a bug in gcc 4.7.x, which has been fixed in gcc
4.8.x, no? We still support gcc 4.7.x in the internal toolchain
backend, if you enable "deprecated options". This way you can check if
a Buildroot toolchain with gcc 4.7 exhibits the same problem.

Note that this kind of issue is often sensitive to optimization flags:
i.e it might fail at -O3 but succeed at -Os.

If we conclude that 4.7 is broken, and >= 4.8 is working, then adding a
dependency on BR2_TOOLCHAIN_GCC_AT_LEAST_4_8 is good enough for me.

Best regards,

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