
On 11 February 2016 at 00:59, Masahiro Yamada yamada.masahiro@socionext.com wrote:
2016-02-11 7:16 GMT+09:00 Stephen Warren swarren@wwwdotorg.org:
From: Stephen Warren swarren@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@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@socionext.com
Acked-by: Simon Glass sjg@chromium.org