Re: A build system using ``Recursive Make Considered harmful''

[Tom Tromey <tromey at redhat dot com>]

>>>>> "Scott" == Scott A Crosby <crosby@qwes.math.cmu.edu> writes:

>> I think it is great that your work confirms the results in the
>> Recursive Make Harmful paper.  Since automake is probably the
>> craziest of the crazy build systems, I think it is reasonable that
>> it look in this direction in the future.  And, in fact, we've been
>> planning this

Scott> Yep.. I thought I'd put up my results and assessments.
Scott> Parallel/distributed building will likely become a more and
Scott> more valuable thing in the future, and its something that is
Scott> very hard to do without this.

Automake already supports parallel builds.  It has for years (I don't
think there was ever a public release that didn't).  Now, in some
situations parallelism is limited because we serialize across
directories.  I doubt that is a very big problem, at least with the
newer versions of GNU make (older versions didn't allow sub-makes to
parallelize).

I think the reason we'd move to a non-recursive build is to speed up
the make step itself.  Hopefully make would stat fewer files in a
fully integrated build.  Also reinvoking make and re-reading Makefiles
has a cost which we would (mostly) avoid.

Tom