NEW BUILD SYSTEM: Cannot build rtems-libbsd
christian.mauderer at embedded-brains.de
Wed Jul 8 06:41:32 UTC 2020
On 08/07/2020 08:35, Niteesh G. S. wrote:
> On Wed, Jul 8, 2020 at 11:52 AM Christian Mauderer
> <christian.mauderer at embedded-brains.de
> <mailto:christian.mauderer at embedded-brains.de>> wrote:
> On 08/07/2020 08:13, Sebastian Huber wrote:
> > On 08/07/2020 08:10, Niteesh G. S. wrote:
> >> On Tue, Jul 7, 2020 at 10:42 AM Sebastian Huber
> >> <sebastian.huber at embedded-brains.de
> <mailto:sebastian.huber at embedded-brains.de>
> >> <mailto:sebastian.huber at embedded-brains.de
> <mailto:sebastian.huber at embedded-brains.de>>> wrote:
> >> Hello,
> >> the problem is that the new build system doesn't export
> >> flags such as -Wl,--gc-sections. The libbsd build should
> enable this
> >> linker option unconditionally.
> >> Thank you. I got it fixed (temporarily) by modifying rtems.py.
> >> conf.env.CFLAGS = cflags['cflags'] + ['-ffunction-sections'] +
> >> ['-fdata-sections']
> > This instructs the compiler to add data elements and functions into
> > separate sections. This is necessary so that the linker can carry out
> > the garbage collection.
> There is an unused function in libbsd that can't link because a function
> it calls isn't there. Till now the two flags had been provided by the
> BSP. It seems that now they are not provided anymore.
> The problematic function is m_unmappedtouio in uipc_mbuf.c. It tries to
> use PHYS_TO_VM_PAGE which isn't defined in libbsd. I think we should
> just remove m_unmappedtouio (with #ifndef __rtems__) on the longer term.
> But not having the -ffunction-sections and -fdata-sections most likely
> makes our binary bigger and maybe leads to other similar bugs. Therefore
> I suggested to add the CFLAGS first.
> >> As per Christian suggestions, I tried exporting CFLAGS with these GCC
> >> flags and then calling ./waf configure but they didn't work.
> > You have to add -Wl,--gc-sections to the linker flags.
> As far as I know Niteesh used that one too. I think for that one LDFLAGS
> worked as a workarround.
> Yes, I did try exporting LDFLAGS too but they also didn't work out.
> I tried the following:
> 1) export LDFLAGS="-Wl,--gc-sections"
> 2) ./waf configure --prefix=$RTEMS/6 --rtems-version=6
> --rtems-bsps=arm/beagleboneblack --buildset=buildset/minimal.ini
> I also tried running
> 1) LDFLAGS="-Wl,--gc-sections" ./waf configure --prefix=$RTEMS/6
> --rtems-version=6 --rtems-bsps=arm/beagleboneblack
> Both of them didn't work out.
Have the flags been ignored and not used or did that not fix the
problem? I would assume the second. You should see the difference if you
call "./waf -v" and take a look at one of the linker calls to generate
the test applications.
> I might be wrong here but waf seems to add the "-Wl,--gc-sections"
> flags if "--function-sections" flags are defined.
That's a bit odd. I don't think that I ever used that flag. But you are
right: If CFLAGS contains the -function-section (only one -),
"-Wl,--gc-sections" is added to the LDFLAGS here.
> Best regards
> embedded brains GmbH
> Herr Christian Mauderer
> Dornierstr. 4
> D-82178 Puchheim
> email: christian.mauderer at embedded-brains.de
> <mailto:christian.mauderer at embedded-brains.de>
> Phone: +49-89-18 94 741 - 18
> Fax: +49-89-18 94 741 - 08
> PGP: Public key available on request.
> Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.
embedded brains GmbH
Herr Christian Mauderer
email: christian.mauderer at embedded-brains.de
Phone: +49-89-18 94 741 - 18
Fax: +49-89-18 94 741 - 08
PGP: Public key available on request.
Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.
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