Re: master 1ca436a: Make compilation mode work with warnings from compiled buffer functions

[Alan Mackenzie]

Hello, Glenn.

On Wed, Nov 28, 2018 at 11:37:55 -0500, Glenn Morris wrote:

> Hi,


> Alan Mackenzie wrote:

> > --- a/lisp/emacs-lisp/bytecomp.el
> > +++ b/lisp/emacs-lisp/bytecomp.el
> > @@ -124,6 +124,7 @@
> >  (require 'backquote)
> >  (require 'macroexp)
> >  (require 'cconv)
> > +(require 'compile)

> I would expect this extra require to slow down bootstrap, for an issue
> that is not relevant to bootstrap (bug#33475)?

I've looked at this, and I don't think there would be other than a
microscopic slowdown.  The previous version of bytecomp.el used at least
one function in compile.el (namely compilation-mode), suggesting that
compile.elc? is already loaded when bytecomp starts.  However, for some
fiddly reason a macro in compile.el was no longer defined, hence the
require.

> Can this be avoided?

Yes it can, by moving the declaration of emacs-lisp-compilation-mode
out of bytecomp.el, probably into compile.el itself.

> Indeed, my automatic overnight build today was about 13 mins, whereas
> every previous day this month was < 11.5 mins.

I've timed several builds, and seen no differences between before and
after, appart from normal measurement error.  I see 2min 29sec +- 1
second for "cold starts", and 2min 3sec += 1 second for a subsequent
build, when all the source files are in filestore cache.

Are you sure that bug #33475 is the cause of your slowdown?

-- 
Alan Mackenzie (Nuremberg, Germany).