Re: [dpdk-dev] meson support : cross compile issues

[Bruce Richardson <bruce.richardson@intel.com>]

On Tue, Feb 27, 2018 at 02:38:53PM +0000, Hemant Agrawal wrote:
> Hi,
> 
> How do we set CROSS COMPILE kernel path support. E.g. something equivalent to RTE_KERNELDIR for Makefile
> 
>      *   Currently the Igb_uio  compilation fails.
>      *   Also, there is no check to disable igb_uio compilation by flag e.g. CONFIG_RTE_EAL_IGB_UIO=n
> 
> 

I have not had time to look at the cross-compilation of kernel modules
yet, so patches welcome. :-)
However, it should be possible to disable the kernel modules generally
using "enable_kmods" option (see meson_options.txt)

> 
> Other minor issue observed is that though the cross compile is set as 6.3, the gcc 7 flags (which is my host compiler version) is getting enabled.  Causing following errors:
> 

Actually, this is a gcc quirk. GCC does not report an error for
cmdline flags disabling unknown warnings, unless other errors are
displayed. This means that when meson tries the options, GCC reports as
supporting them. It also means that it's not a problem when you do see
them - just fix the other errors and the warnings about the flags will
disappear.

See: https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html
"However, if the -Wno- form is used, the behavior is slightly different:
no diagnostic is produced for -Wno-unknown-warning unless other
diagnostics are being produced. This allows the use of new -Wno- options
with old compilers, but if something goes wrong, the compiler warns that
an unrecognized option is present"


> ../drivers/bus/dpaa/dpaa_bus.c: At top level:
> 
> cc1: warning: unrecognized command line option ‘-Wno-format-truncation’
> 
> cc1: warning: unrecognized command line option ‘-Wno-address-of-packed-member’
> 
> Regards,
> Hemant
> 
Regards,
/Bruce