Re: [Xen-devel] [PATCH v5 03/10] x86: determine HAVE_AS_* just once

[Anthony PERARD <anthony.perard@xxxxxxxxxx>]

On Thu, Mar 26, 2020 at 10:50:48AM +0100, Jan Beulich wrote:
> On 25.03.2020 22:12, Andrew Cooper wrote:
> > All the requisite infrastructure looks to be already present.
> 
> ... there's the one open prereq question of what happens upon
> tool chain updates. It's not clear to me if/how kconfig would
> get invoked despite none of the recorded dependencies having
> changed in such a case. (I'm sure you realize there's no issue
> with this when the determination occurs out of a makefile.)

We might need one small change for this to happen, it is to add a
comment in .config which display the output of `$(CC) --version | head
-1`. Simple :-).
If the output of `$(CC) --version` changes, kconfig will run again. That
would be enough to detect tool chain updates, right?

Have a look at "include/config/auto.conf.cmd" to find out how kconfig is
forced to run again.

I'll prepare a patch.

-- 
Anthony PERARD