Re: [RFC] kbuild - introduce vdir to make life easier for x86_64

[Sam Ravnborg <sam@ravnborg.org>]

On Tue, Sep 11, 2007 at 12:40:41AM +0200, Andi Kleen wrote:
> 
> > The below are the minimal clean-up - a bit more could be done.
> > 
> > Comments?
> 
> Looks good in principle. My only suggestion would be to name it something
> differently than vdir. I know that's what GNU make calls it, but it's still
> pretty cryptic. How about just fallback-dir ? 
fallback-dir is better.
vdir came from make's vpath but then very few knows about vpath anyway so that 
was not the best source of inspiration.

 
> Also what would be nice (I don't know if it's doable in make) would
> be a separate variable (e.g. other-obj-... := ) that contains the fallback
> names and that is double checked against the fallback directory.
My first attempt was along these lines but I dropped it for two reasons:
1) Mixing obj-y and other-obj-y assinment broke all assumptions on linkorder.
   It would not be possible to link objexts in order a1.o, a2.o, a3.o if a1.o
   and a3.o were assigned to obj-y and a2.o was assigned to other-obj-y. 

2) It needed a decent amouth of unreadable gmake-foo to introduce
   a second variable. And the learning curve for kbuild internals are alreay
   to steep so I try to avoid additional complexity.

I'm a bit reluctant to just enable the fallback-dir functionality.
There is no point in adding this for the sake of x86 if we merge
i386 and x86_64 a few days after.

	Sam