[U-Boot] [PATCH V3] Makefile: remove BUILD_TAG from KBUILD_CFLAGS

[Masahiro Yamada]

2016-02-11 7:16 GMT+09:00 Stephen Warren <swarren at wwwdotorg.org>:
> From: Stephen Warren <swarren at nvidia.com>
>
> If BUILD_TAG is part of KBUILD_CFLAGS, then any time the value changes,
> all files get rebuilt. In a continuous integration environment, the value
> will change every build. This wastes time, assuming that incremental
> builds would otherwise occur.
>
> To solve this, remove BUILD_TAG from KBUILD_CFLAGS and add it to CFLAGS
> for just the one file that uses it. This does have the disadvantage that
> if any other files want to use the flag, we'll need to duplicate this
> custom CFLAGS setup logic. However, it seems unlikely we'll need this.
>
> An alternative would be to add BUILD_TAG to the "local version" and remove
> the special case code from display_options.c. However, that would affect
> the format of the U-Boot signon message, which may negatively affect
> people looking for specific data there. The approach of using
> file-specific CFLAGS was suggested by Masahiro Yamada.
>
> Signed-off-by: Stephen Warren <swarren at nvidia.com>
> ---
> v3: Undo accidental removal of bch.o.
> v2: Set CFLAGS on display_options.c rather than modifying
> scripts/setlocalversion to add BUILD_TAG to the local version.


Reviewed-by: Masahiro Yamada <yamada.masahiro at socionext.com>


-- 
Best Regards
Masahiro Yamada