Re: [Sbcl-help] :sb-after-xc-core

[Nikodemus S. <tsi...@cc...>]

On Fri, 16 Apr 2004, David Steuber wrote:

> I've seen this documentation:
>
>  ;; This isn't really a target Lisp feature at all, but controls
>  ;; whether the build process produces an after-xc.core file. This
>  ;; can be useful for shortening the edit/compile/debug cycle when
>  ;; you modify SBCL's own source code, as in slam.sh. Otherwise
>  ;; you don't need it.
>  ; :sb-after-xc-core
>
> But I am not quite clear on something.  Is this feature supposed to
> allow me to reduce build times when I update from CVS?  If so, it
> doesn't seem to do that.  If not, I guess I should just take it out
> of my customize-target-features.lisp file.

Hopefully someone will hit me with a stick if a get something wrong...

"If you're lucky."

The after-xc-core is a way to shortcut the build-procedure by saving a
host-lisp core after the cross-compiler has been built. It can by utilized
by building with slam.sh instead of make.sh: only those target files (and
those later in build-order.lisp-expr) that have changed will be rebuilt,
the cross-compiler is not rebuilt at all.

To use it you must build with the same host lisp that saved the
after-xc-core, and hope that things that need to be built for the
cross-compiler have not changed.

If all this holds true, it can provide a hefty speedup, but I would not
personally recommed it for just rebuilding from the CVS -- I believe it's
essentially intended to be used by lazy sbcl hackers who know/think/hope
that whatever they have changed doesn't require a full build.

In the same vein loading src/cold/chill.lisp into a live sbcl will allow
loading some bits and pieces of sbcl codebase into the thusly chilled
sbcl, allowing experimentation without even slamming -- but neither this
will work for all of the codebase.

Cheers,

 -- Nikodemus