From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.ciao.gmane.io!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.bugs Subject: bug#41321: 27.0.91; Emacs aborts due to invalid pseudovector objects Date: Sat, 30 May 2020 19:32:46 +0300 Message-ID: <83v9kdl6xd.fsf@gnu.org> References: <83zha8cgpi.fsf@gnu.org> <83imgublku.fsf@gnu.org> <831rncjuwf.fsf@gnu.org> <83h7w5xvfa.fsf@gnu.org> <83y2phwb9x.fsf@gnu.org> <83r1v9w9vi.fsf@gnu.org> <83mu5xw50d.fsf@gnu.org> <83k110wxte.fsf@gnu.org> <4bab5f55-95fe-cf34-e490-1d4319728395@cs.ucla.edu> <837dwyvi74.fsf@gnu.org> <1484f569-c260-9fb0-bfe1-67897de289d3@cs.ucla.edu> <83blm9tn4j.fsf@gnu.org> <4aeb8963-4fd1-fcd4-e6e1-be409ab54775@cs.ucla.edu> <83tuzzrk30.fsf@gnu.org> <749bc7d0-6376-ec2e-7f84-dcd3a3cea465@cs.ucla.edu> <83sgfjqn49.fsf@gnu.org> <83eer2m0b6.fsf@gnu.org> <83367hn624.fsf@gnu.org> <831rn1mzgp.fsf@gnu.org> Injection-Info: ciao.gmane.io; posting-host="ciao.gmane.io:159.69.161.202"; logging-data="2028"; mail-complaints-to="usenet@ciao.gmane.io" Cc: eggert@cs.ucla.edu, 41321@debbugs.gnu.org, monnier@iro.umontreal.ca To: Pip Cet Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Sat May 30 18:33:09 2020 Return-path: Envelope-to: geb-bug-gnu-emacs@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 1jf4Q0-0000P7-TM for geb-bug-gnu-emacs@m.gmane-mx.org; Sat, 30 May 2020 18:33:08 +0200 Original-Received: from localhost ([::1]:34984 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jf4Q0-0007WD-04 for geb-bug-gnu-emacs@m.gmane-mx.org; Sat, 30 May 2020 12:33:08 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:48218) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jf4Pu-0007W5-8O for bug-gnu-emacs@gnu.org; Sat, 30 May 2020 12:33:02 -0400 Original-Received: from debbugs.gnu.org ([209.51.188.43]:47423) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1jf4Pt-0007pA-R8 for bug-gnu-emacs@gnu.org; Sat, 30 May 2020 12:33:01 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1jf4Pt-0006IT-O4 for bug-gnu-emacs@gnu.org; Sat, 30 May 2020 12:33:01 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Eli Zaretskii Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Sat, 30 May 2020 16:33:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 41321 X-GNU-PR-Package: emacs Original-Received: via spool by 41321-submit@debbugs.gnu.org id=B41321.159085637724195 (code B ref 41321); Sat, 30 May 2020 16:33:01 +0000 Original-Received: (at 41321) by debbugs.gnu.org; 30 May 2020 16:32:57 +0000 Original-Received: from localhost ([127.0.0.1]:58969 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1jf4Pp-0006IB-K9 for submit@debbugs.gnu.org; Sat, 30 May 2020 12:32:57 -0400 Original-Received: from eggs.gnu.org ([209.51.188.92]:40782) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1jf4Pn-0006Hy-FU for 41321@debbugs.gnu.org; Sat, 30 May 2020 12:32:55 -0400 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]:37856) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jf4Ph-0007mL-Nu; Sat, 30 May 2020 12:32:49 -0400 Original-Received: from [176.228.60.248] (port=3247 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1jf4Pg-0007nv-RV; Sat, 30 May 2020 12:32:49 -0400 In-Reply-To: (message from Pip Cet on Sat, 30 May 2020 13:29:33 +0000) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Original-Sender: "bug-gnu-emacs" Xref: news.gmane.io gmane.emacs.bugs:181237 Archived-At: > From: Pip Cet > Date: Sat, 30 May 2020 13:29:33 +0000 > Cc: eggert@cs.ucla.edu, 41321@debbugs.gnu.org, > Stefan Monnier > > > > > So this alignment requirement is only due to pthreads being used? > > > > > > I'm not sure what you're asking. Obviously there are systems on which > > > unaligned accesses will fault or be very slow indeed, so we need to > > > make sure, say, pure space allocations are aligned somehow. That > > > requires a LISP_ALIGNMENT of 8. Everything beyond that is only for > > > performance, pthreads, and SIMD types. > > > > If the system guarantees 4-byte alignment from malloc (and/or a > > similar alignment of the runtime C stack), then using that doesn't > > trigger problems related to unaligned accesses, right? So let me > > rephrase: why isn't 4-byte alignment "good enough" for us on systems > > where malloc and the runtime stack are guaranteed to be thus aligned? > > (The runtime stack isn't relevant, as far as I can tell, since we walk > that in 4-byte steps on such systems anyway.) I think it might be relevant for stack-based Lisp objects (if we keep requiring that Lisp objects are 8-byte aligned on 32-bit platforms). > You're correct that on such a system, we could get away with a > LISP_ALIGNMENT of 4, but a LISP_ALIGNMENT of 8 wouldn't hurt either. That's for sure. I just wondered why did we start requiring 8-byte alignment back when we did. Perhaps someone still remembers the reason.