From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Andrea Corallo via "Emacs development discussions." Newsgroups: gmane.emacs.devel Subject: Re: Updating *.el files and native compilation Date: Mon, 10 May 2021 15:44:16 +0000 Message-ID: References: <83mtt5acjw.fsf@gnu.org> <837dk67lvw.fsf@gnu.org> Reply-To: Andrea Corallo Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="27588"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux) Cc: emacs-devel@gnu.org To: Eli Zaretskii Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Mon May 10 17:45:02 2021 Return-path: Envelope-to: ged-emacs-devel@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1lg85d-00070j-9E for ged-emacs-devel@m.gmane-mx.org; Mon, 10 May 2021 17:45:01 +0200 Original-Received: from localhost ([::1]:39032 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lg85c-0007N4-Ca for ged-emacs-devel@m.gmane-mx.org; Mon, 10 May 2021 11:45:00 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:54424) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lg851-0006eL-IP for emacs-devel@gnu.org; Mon, 10 May 2021 11:44:23 -0400 Original-Received: from mx.sdf.org ([205.166.94.24]:52527) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lg84w-0007O2-Ag; Mon, 10 May 2021 11:44:23 -0400 Original-Received: from mab (ma.sdf.org [205.166.94.33]) by mx.sdf.org (8.15.2/8.14.5) with ESMTPS id 14AFiG9T006665 (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits) verified NO); Mon, 10 May 2021 15:44:16 GMT In-Reply-To: <837dk67lvw.fsf@gnu.org> (Eli Zaretskii's message of "Mon, 10 May 2021 16:34:43 +0300") Received-SPF: pass client-ip=205.166.94.24; envelope-from=akrl@sdf.org; helo=mx.sdf.org X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.23 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-mx.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.io gmane.emacs.devel:269123 Archived-At: Eli Zaretskii writes: >> From: Andrea Corallo >> Cc: emacs-devel@gnu.org >> Date: Mon, 10 May 2021 07:35:53 +0000 >> >> > . if, for some reason, Emacs loads an incompatible .eln file, then >> > some Lisp programs could crash the Emacs session, is that correct? >> > If so, how do we make sure such incompatible changes always cause >> > a new native compilation that yields a different file name for the >> > .eln file? >> >> Yes but this should not happen, every change that can introduce an >> incompatibility has to be accounted in the `comp-abi-hash' computation >> and AFAIK ATM it is. > > Some changes don't require updating comp-abi-hash, but still create > *.eln files with different hashes in its name. AFAIU, that happens > when the primitives don't change, but the .el file itself changes, > isn't that so? Correct > In any case, are you saying that the only situations where loading and > using a .eln file could crash Emacs are those which are handled by > changing comp-abi-hash? Yes > If so, how can we make sure we never fail to update comp-abi-hash when > that is needed? The vast majority of the cases is when some subr is added or a signature is changed and we account for this automatically. The rest should be only about changes specific to the eln load mechanism in comp.c. I hope who does that is very well aware of consequences but I don't know if there's a way we can automatically guard against these changes breaking the system (I guess there's not). Regards Andrea