From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:44478) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hH2J4-0007Xm-24 for qemu-devel@nongnu.org; Thu, 18 Apr 2019 04:22:06 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hH2J3-0004W2-3q for qemu-devel@nongnu.org; Thu, 18 Apr 2019 04:22:06 -0400 Received: from mx1.redhat.com ([209.132.183.28]:60042) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hH2J2-0004Vj-IG for qemu-devel@nongnu.org; Thu, 18 Apr 2019 04:22:04 -0400 From: Markus Armbruster References: <3246431b-8d6e-f2bc-e0f0-99d80384d97b@redhat.com> Date: Thu, 18 Apr 2019 10:21:59 +0200 In-Reply-To: <3246431b-8d6e-f2bc-e0f0-99d80384d97b@redhat.com> (Paolo Bonzini's message of "Wed, 6 Mar 2019 19:12:33 +0100") Message-ID: <87v9zbpvtk.fsf@dusky.pond.sub.org> MIME-Version: 1.0 Content-Type: text/plain Subject: Re: [Qemu-devel] converting build system to Meson? List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: qemu-devel , Peter Maydell , Thomas Huth , =?utf-8?Q?M?= =?utf-8?Q?arc-Andr=C3=A9?= Lureau , Richard Henderson Paolo Bonzini writes: > Hi all, > > lately I have been thinking of converting the QEMU build system to > Meson. Meson is a relatively new build system that can replace > Autotools or hand-written Makefiles such as QEMU; as a die-hard > Autotools fan, I must say that Meson is by far better than anything else > that has ever tried to replace Autotools, and actually has the potential > to do so. > > Advantages of Meson that directly matter for QEMU include: > > - build definitions in a very readable and user friendly DSL, which > supports looping and conditions. > > - ability to introspect the build definitions so that you can find out > what is built without building it (the DSL is not Turing complete and > most objects in it are immutable, so it cannot be abused that much :)) > > - support for a non-recursive build from per-subdirectory input (similar > to Makefile.objs) Could Meson build the $(TARGET_DIRS) non-recursively? I'm asking because I find the make recursion there annoying. As usual with recursion, we have to dumb down dependencies: if anything made by the recursion needs X, then everything does. If making X fails, we don't recurse. Defeats -k. > - ease of distributing a full copy of Meson to support distros that ship > an older version (no dependencies apart from Python 3.5). At 40000 > lines of Python, Meson is relatively small. [...] From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5E688C10F0B for ; Thu, 18 Apr 2019 08:23:00 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D62C2217D7 for ; Thu, 18 Apr 2019 08:22:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D62C2217D7 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([127.0.0.1]:37865 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hH2Ju-0007su-S9 for qemu-devel@archiver.kernel.org; Thu, 18 Apr 2019 04:22:58 -0400 Received: from eggs.gnu.org ([209.51.188.92]:44478) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hH2J4-0007Xm-24 for qemu-devel@nongnu.org; Thu, 18 Apr 2019 04:22:06 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hH2J3-0004W2-3q for qemu-devel@nongnu.org; Thu, 18 Apr 2019 04:22:06 -0400 Received: from mx1.redhat.com ([209.132.183.28]:60042) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hH2J2-0004Vj-IG for qemu-devel@nongnu.org; Thu, 18 Apr 2019 04:22:04 -0400 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 9D39230ADBB1; Thu, 18 Apr 2019 08:22:03 +0000 (UTC) Received: from blackfin.pond.sub.org (ovpn-116-116.ams2.redhat.com [10.36.116.116]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 4688F600C2; Thu, 18 Apr 2019 08:22:01 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id CB5B81138648; Thu, 18 Apr 2019 10:21:59 +0200 (CEST) From: Markus Armbruster To: Paolo Bonzini References: <3246431b-8d6e-f2bc-e0f0-99d80384d97b@redhat.com> Date: Thu, 18 Apr 2019 10:21:59 +0200 In-Reply-To: <3246431b-8d6e-f2bc-e0f0-99d80384d97b@redhat.com> (Paolo Bonzini's message of "Wed, 6 Mar 2019 19:12:33 +0100") Message-ID: <87v9zbpvtk.fsf@dusky.pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.47]); Thu, 18 Apr 2019 08:22:03 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] converting build system to Meson? X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Maydell , Thomas Huth , Richard Henderson , qemu-devel , =?utf-8?Q?M?= =?utf-8?Q?arc-Andr=C3=A9?= Lureau Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Message-ID: <20190418082159.KNCw2tELpXVgvtzmym_87-GE5NOz_WhzZeqzt2qyptM@z> Paolo Bonzini writes: > Hi all, > > lately I have been thinking of converting the QEMU build system to > Meson. Meson is a relatively new build system that can replace > Autotools or hand-written Makefiles such as QEMU; as a die-hard > Autotools fan, I must say that Meson is by far better than anything else > that has ever tried to replace Autotools, and actually has the potential > to do so. > > Advantages of Meson that directly matter for QEMU include: > > - build definitions in a very readable and user friendly DSL, which > supports looping and conditions. > > - ability to introspect the build definitions so that you can find out > what is built without building it (the DSL is not Turing complete and > most objects in it are immutable, so it cannot be abused that much :)) > > - support for a non-recursive build from per-subdirectory input (similar > to Makefile.objs) Could Meson build the $(TARGET_DIRS) non-recursively? I'm asking because I find the make recursion there annoying. As usual with recursion, we have to dumb down dependencies: if anything made by the recursion needs X, then everything does. If making X fails, we don't recurse. Defeats -k. > - ease of distributing a full copy of Meson to support distros that ship > an older version (no dependencies apart from Python 3.5). At 40000 > lines of Python, Meson is relatively small. [...]