[libcamera-devel] Fwd: [autobuild.buildroot.net] Your daily results for 2019-09-04 [atomic link failure]

[Laurent Pinchart]

Hi Kieran,

On Thu, Sep 05, 2019 at 08:41:48AM +0100, Kieran Bingham wrote:
> Hello Libcameroonians.
> 
> This is just a notification mail.
> 
> Our build has failed for Sparc architectures which require manual
> addition of libatomic. (I believe this may also affect MIPS).
> 
> Buildroot is adding a manual addition of -latomic to the LDFLAGS [0]:
> 
> > +# Uses __atomic_fetch_add_4
> > +ifeq ($(BR2_TOOLCHAIN_HAS_LIBATOMIC),y)
> > +LIBCAMERA_LDFLAGS += -latomic
> > +endif
> 
> [0] http://lists.busybox.net/pipermail/buildroot/2019-September/258630.html
> 
> I wonder if we should catch this in meson.build in some fashion and also
> add -latomic ...
> 
> Seems IGT are trying to tackle a similar issue in meson [1] - but the
> results aren't all that pretty and requires a somewhat GCC specific
> compilation test to be included which I'd rather avoid:
> 
> > +if cc.links('''
> > +#include <stdint.h>
> > +int main(void) {
> > +  uint32_t x32 = 0;
> > +  uint64_t x64 = 0;
> > +  __atomic_load_n(&x32, __ATOMIC_SEQ_CST);
> > +  __atomic_load_n(&x64, __ATOMIC_SEQ_CST);
> > +  return 0;
> > +}''', name : 'built-in atomics')
> > +	libatomic = null_dep
> > +else
> > +	libatomic = cc.find_library('atomic')
> > +endif
> 
> [1] https://patchwork.kernel.org/patch/11001547/
> 
> 
> I don't think this is a high priority right now, and a resolution is
> already posted for BR.
> 
> So just leaving this on the ML for future reference, for if/when it
> comes up.

Thank you for the information. I'm indeed tempted to ignore this issue
for now, until someone actually wants to use libcamera on sparc :-) And
possibly let distribution handle this...

I'm also not sure where our usage of __atomic_* comes from.

> -------- Forwarded Message --------
> Subject: [autobuild.buildroot.net] Your daily results for 2019-09-04
> Date: Thu, 05 Sep 2019 06:17:40 -0000
> From: Thomas Petazzoni <thomas.petazzoni at bootlin.com>
> To: Kieran Bingham <kieran.bingham at ideasonboard.com>
> 
> Hello,
> 
> Autobuilder failures
> ====================
> 
> This is the list of Buildroot build failures that occurred on
> 2019-09-04, and for which you are a registered architecture developer
> or package developer. Please help us improving the quality of
> Buildroot by investigating those build failures and sending patches to
> fix them. Thanks!
> 
> Results for the 'master' branch
> -------------------------------
> 
> Build failures related to your packages:
> 
>     arch     |             reason             |
>               url
> -------------+--------------------------------+---------------------------------------------------------------------------------
>    sparc     | libcamera-caf25dc5cfd11b965... |
> http://autobuild.buildroot.net/results/1f0b8338f5f39aa86b9d432598dae2f53c5f7c84
> 

-- 
Regards,

Laurent Pinchart