[Re: [PATCH 0/5] RFC: strip 15,000 lines from a typical autoconf.h] On 12/04/2012 (Thu 12:29) Linus Torvalds wrote:
> On Wed, Apr 11, 2012 at 8:10 PM, Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> wrote:
> >
> > Can we leave the CONFIG_ part in the caller, so they are still grepable, please?
> >
> > So:
> >
> > #define config_enabled(x) (__stringify(x)[0] == '1')
>
> Sure. Except G+ came through, and we now have an even better hack for
> this, that works entirely in the preprocessor.
>
> That also means that you can use it for static initializers etc, so you can do
>
> int some_value = config_enabled(CONFIG_ENABLE_XYZ_BY_DEFAULT);
>
> Paul, do you want to write the patch to change IS_ENABLED() to use this trick?
Sure -- I've done this in patch #1 of the (now) three patches.
I've dropped all the patches relating to phasing out the users
of IS_ENABLED within C code, since now they should just work.
>
> Trick courtesy of "comex ." on G+ (please do give him credit even if
> he doesn't seem to use his real name):
>
> #define is_set(macro) is_set_(macro)
> #define macrotest_1 ,
> #define is_set_(value) is_set__(macrotest_##value)
> #define is_set__(comma) is_set___(comma 1, 0)
> #define is_set___(_, v, ...) v
>
> and now "is_set(CONFIG_xyzzy)" works, and gives either 1 or 0 directly
> in the preprocessor.
>
> Obviously the names have to be changed here (let's not use
> "macrotest_1" - make it something more internal), but the concept is
> solid, and I would actually suggest having this as a generic "is this
> macro set to 1" helper first, and then implement IS_ENABLED() in terms
> of that.
Hopefully the names I've chosen are OK. Please have a look.
Thanks,
Paul.
>
> My likee.
>
> Linus
Paul Gortmaker (3):
kconfig: fix IS_ENABLED to not require all options to be defined
Revert "kconfig: fix __enabled_ macros definition for invisible and
un-selected symbols"
kconfig: delete last traces of __enabled_ from autoconf.h
include/linux/kconfig.h | 22 ++++++++++++++++++----
scripts/kconfig/confdata.c | 38 ++------------------------------------
2 files changed, 20 insertions(+), 40 deletions(-)
--
1.7.9.1
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