[U-Boot] [PATCH 1/2] Makefile: use if_change_dep for u-boot.cfg

[Simon Glass]

Hi Masahiro,

On 23 September 2016 at 03:32, Masahiro Yamada
<yamada.masahiro at socionext.com> wrote:
> 2016-09-23 13:16 GMT+09:00 Simon Glass <sjg at chromium.org>:
>> On 19 September 2016 at 12:20, Stephen Warren <swarren at wwwdotorg.org> wrote:
>>> From: Stephen Warren <swarren at nvidia.com>
>>>
>>> cmd_cpp_cfg generates a dependency output, but because it's invoked using
>>> if_changed rather than if_changed_dep, that dependency file is ignored.
>>> This results in Kbuild not knowing about which files u-boot.cfg depends
>>> on, so it may not be rebuilt when required.
>>>
>>> A practical result of this is that u-boot.cfg may continue to reference
>>> CONFIG_ options that no longer exist in the source tree, and this can
>>> cause the adhoc config options check to fail.
>>>
>>> This change modifies Makefile to use if_changed_dep, which in turn causes
>>> all dependencies to be known to the next make invocation.
>>>
>>> Signed-off-by: Stephen Warren <swarren at nvidia.com>
>
>
> In the first place, why do we need u-boot.cfg?
>
> CONFIG options from board headers are already collected in include/autoconf.mk.
>
> I think the most correct way is to rework check-config.sh
> to parse include/autoconf.mk (I can do this).
>
> Then, remove all of the u-boot.cfg rules.

This file is intended to allow buildman to see all the CONFIG options
that are set, whether in #defines or in Kconfig.

Regards,
Simon