Re: Future plans for Autotools

[Paul Smith]

On Sun, 2021-01-24 at 16:26 -0700, Tom Tromey wrote:
> I think it would be good.  I'm curious if it is known to be faster or
> if that's just an expectation.  I'd also be very interested to learn
> which changes would make the result faster.

Speaking for myself I'm not convinced requiring GNU make would be a lot
faster.

The only thing that would make much of a performance difference, I
think, is if we are able to replace lots of shell invocations with
built-in make functions like wildcard, if, etc.  However I'm not sure
there's enough opportunity for that to matter.

If GNU make provided a more comprehensive suite of functions that could
replace a lot of basic shell commands like rm, mkdir, etc. then it
would be more compelling: not only would it be a bit faster but more
importantly it would add a lot of portability.  But, it doesn't.

I guess there's one other thing that MIGHT make a difference: we could
use static pattern rules instead of suffix rules.  Because they are
explicit rules they don't have to go through rule search, which makes
them more efficient.

But of course, since automake already knows all the sources it could
also just generate explicit rules for everything.

I'm not sure that the benefits are there, UNLESS the automake
developers feel like being able to rely on GNU make would be a help to
them.  So I would defer to their preferences: if they feel hamstrung by
not having GNU make features available that's a good reason to change.