From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED.blaine.gmane.org!not-for-mail From: "Daniel Colascione" Newsgroups: gmane.emacs.devel Subject: Re: CHECK_STRUCTS/dmpstruct.h mechanism is broken. Date: Thu, 11 Apr 2019 15:10:35 -0700 Message-ID: <4b117557f2ad040a178587a74ad4d998.squirrel@dancol.org> References: <20190228202146.GC4686@ACM> <20190228205955.GD4686@ACM> <20190410162203.GA4009@ACM> <9809d5ce-c1c4-48e9-6dac-489431b34067@cs.ucla.edu> <671ba8dd-894b-5698-d162-8901b1098b9a@cs.ucla.edu> <87v9zkqptq.fsf@Rainer.invalid> Mime-Version: 1.0 Content-Type: text/plain;charset=iso-8859-1 Content-Transfer-Encoding: 8bit Injection-Info: blaine.gmane.org; posting-host="blaine.gmane.org:195.159.176.226"; logging-data="74730"; mail-complaints-to="usenet@blaine.gmane.org" User-Agent: SquirrelMail/1.4.23 [SVN] Cc: emacs-devel@gnu.org To: "Achim Gratz" Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Fri Apr 12 00:11:01 2019 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([209.51.188.17]) by blaine.gmane.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:256) (Exim 4.89) (envelope-from ) id 1hEhuN-000JHy-Vi for ged-emacs-devel@m.gmane.org; Fri, 12 Apr 2019 00:11:01 +0200 Original-Received: from localhost ([127.0.0.1]:55567 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hEhuM-0001qd-12 for ged-emacs-devel@m.gmane.org; Thu, 11 Apr 2019 18:10:58 -0400 Original-Received: from eggs.gnu.org ([209.51.188.92]:35299) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hEhuF-0001qV-1t for emacs-devel@gnu.org; Thu, 11 Apr 2019 18:10:52 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hEhuB-0004T5-BL for emacs-devel@gnu.org; Thu, 11 Apr 2019 18:10:50 -0400 Original-Received: from dancol.org ([2600:3c01::f03c:91ff:fedf:adf3]:33112) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1hEhuA-0004Jz-GM for emacs-devel@gnu.org; Thu, 11 Apr 2019 18:10:47 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=dancol.org; s=x; h=Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:To:From:Subject:Date:References:In-Reply-To:Message-ID; bh=UgJXzytIYXYo6Kh8fkG3TvTpoELbqZw2UAXuIt5Z14k=; b=LHeH4yYeHznwknnuMe3EHx7a8+zRkLNPAjzoQ/TARmqaSys1jedNsffxmvA21/3PpndTlzpxvAF9ODHwrVJ094Vd0+vmITbXFe0djbelgjvke7P6U6aLqJ1qVNk4lIXHv23xsI+INMftzpvDxXLZFAELEmIRt0xSPSVoElMMv6afEoV+n+jEwMD6RFDWq40CzMHHhViHktnZrgSg3xDt+ZVaTMm5XrfiLPvZ3wMhVxKR11EjyIe7jtejrBfoy92s3yY6AyVTPkt+K0xcTANiP2/9jTys6VghmTyAuDvbDuAUB9ySzSF0RbkVZtXtE5WSIXy9JTfY1VlaASx8KKyCIw==; Original-Received: from localhost ([127.0.0.1] helo=dancol.org) by dancol.org with esmtp (Exim 4.84_2) (envelope-from ) id 1hEhtz-0004vf-Qv; Thu, 11 Apr 2019 15:10:35 -0700 Original-Received: from 127.0.0.1 (SquirrelMail authenticated user dancol) by dancol.org with HTTP; Thu, 11 Apr 2019 15:10:35 -0700 In-Reply-To: <87v9zkqptq.fsf@Rainer.invalid> X-Priority: 3 (Normal) Importance: Normal X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2600:3c01::f03c:91ff:fedf:adf3 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.org gmane.emacs.devel:235309 Archived-At: > Paul Eggert writes: >> On 4/11/19 2:35 AM, Robert Pluim wrote: >>> Much as I dislike Autoconf, what would you have us replace it with? >> >> I was thinking of using just standard tools (as per the GNU Coding >> Standards) along with GNU Make - and, once the Emacs core is built, we >> can use Emacs itself. Although we started assuming GNU Make in Emacs 25, >> we haven't been using GNU Make's features fully and some of its features >> could effectively replace the need for Autoconf. > > I don't see how… autoconf got one thing right: it tries to actually > _compile_, not just check preprocessor defines or compiler versions. > That also makes it slow, especially as it's all serial. > >> A benefit of this approach would be faster builds. Right now the biggest >> bottleneck on my system is the time to run 'configure' whenever I make a >> trivial change to configure.ac or whatever. I *hate* that. > > The fun thing is that in this case you could run autoconf almost > entirely from already cached decisions. I have not tried to feed > autoconf prepared caches in a long time, but it may be worth a try. > >> Although I looked into other possible approaches (switching to SCons, >> say) none of them seemed to offer compelling advantages to the >> more-conservative approach I have in mind. > > Most of the newfangled systems I've looked at focus on build speed > (mostly by pre-computing dependencies) and take the configuration for > granted (some even using autoconf again). > >> Eric Raymond reported success with this sort of approach when >> deautoconfiscating giflib and the NTP code base: >> >> https://lists.gnu.org/r/bison-patches/2019-02/msg00041.html > > I can tell you something about NTPsec. Yes, it has no autoconf, but > that's been replaced with the configure step from waf, which has exactly > one person you can ask if something doesn't work the way you think it > should. Based on Python it has a somewhat more agreeable syntax than M4 > macros (no surprise), but it's not actually more clear (to me anyway). > Plus, there are a lot less depencies that need to be checked. I like autoconf. It's flexible and it works for every weird thing I've ever wanted to do with it. Trying to color outside the lines with alternate systems like cmake has been hell. While m4 isn't the most elegant macro system out there, its quirks are well-understood, and autoconf has decades of institutional knowledge built into it. I've also found that alternative systems frequently have problems with complex configurations like out-of-tree builds, cross compilation, various forms of path overriding, and tool specification. autoconf dealt with all of these issues a very long time ago. IMHO, instead of investing in some new system, we'd be better off improving autoconf speed by 1) eliminating tests that have become unnecessary in the modern world, 2) adding an optimization pass that batched redundant tests, and 3) making caching Just Work, maybe by stracing and checking all inputs for cache validation. The basic model is fine. The basic configuration model is fine.