Re: diet-kconfig: a script to trim unneeded kconfigs

[Takashi Iwai <tiwai@suse.de>]

At Tue, 23 Sep 2008 11:15:19 -0700,
Chris Li wrote:
> 
> On Tue, Sep 23, 2008 at 4:31 AM, Takashi Iwai <tiwai@suse.de> wrote:
> > That is true.  Enabling arbitrary kernel config item is hard to
> > achieve right now.  I think this feature should be implemented in
> > kbuild parser itself.  The current reverse-select is way limited and
> > known to be problematic in many kernel configs.
> 
> I was looking at the kbuild system. BTW, I really like the Makefile
> in kbuild.  For the reverse select, here is what I have in mind.
> 
> The reverse select needs to maintain the define-user chain for
> each kernel option. And each kernel option has a list of the kernel
> option and value pare to enable an option. Once we produce such
> an list for "all config". We can know exactly what kernel option
> needs to set in order to get to so module. It is kind of doing
> the data flow analyze on the config options.
> 
> It is not trivial, but it shouldn't be too hard either.

Well, it is not so easy, too.
The good-working reverse selection with dependency checks is a
feature we've long for in Kconfig, but it hasn't been implemented
because it could easily introduce a messy dependency loop, or some
cases are not easily resolvable.

Anyway, the development of reverse-selection should involve with Sam
and other Kbuild maintainer/developers.


Takashi