From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.bugs Subject: bug#54532: [PATCH] sorting Date: Thu, 24 Mar 2022 08:42:39 +0200 Message-ID: <831qyretr4.fsf@gnu.org> References: <320D86FD-5B2E-4177-9570-A8004A942E8C@acm.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="23554"; mail-complaints-to="usenet@ciao.gmane.io" Cc: acohen@ust.hk, 54532@debbugs.gnu.org To: Mattias =?UTF-8?Q?Engdeg=C3=A5rd?= Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Thu Mar 24 07:43:30 2022 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 1nXHBw-0005v4-VB for geb-bug-gnu-emacs@m.gmane-mx.org; Thu, 24 Mar 2022 07:43:29 +0100 Original-Received: from localhost ([::1]:54320 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nXHBv-0005TU-HM for geb-bug-gnu-emacs@m.gmane-mx.org; Thu, 24 Mar 2022 02:43:27 -0400 Original-Received: from eggs.gnu.org ([209.51.188.92]:60798) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nXHBX-0005T7-5G for bug-gnu-emacs@gnu.org; Thu, 24 Mar 2022 02:43:03 -0400 Original-Received: from debbugs.gnu.org ([209.51.188.43]:52755) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1nXHBW-0005G6-Sn for bug-gnu-emacs@gnu.org; Thu, 24 Mar 2022 02:43:02 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1nXHBW-0003M9-HD for bug-gnu-emacs@gnu.org; Thu, 24 Mar 2022 02:43:02 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Eli Zaretskii Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Thu, 24 Mar 2022 06:43:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 54532 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: patch Original-Received: via spool by 54532-submit@debbugs.gnu.org id=B54532.164810417612884 (code B ref 54532); Thu, 24 Mar 2022 06:43:02 +0000 Original-Received: (at 54532) by debbugs.gnu.org; 24 Mar 2022 06:42:56 +0000 Original-Received: from localhost ([127.0.0.1]:46652 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1nXHBP-0003Lk-KB for submit@debbugs.gnu.org; Thu, 24 Mar 2022 02:42:55 -0400 Original-Received: from eggs.gnu.org ([209.51.188.92]:57004) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1nXHBO-0003LS-2L for 54532@debbugs.gnu.org; Thu, 24 Mar 2022 02:42:54 -0400 Original-Received: from [2001:470:142:3::e] (port=51008 helo=fencepost.gnu.org) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nXHBH-0005FB-Vb; Thu, 24 Mar 2022 02:42:47 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=gnu.org; s=fencepost-gnu-org; h=MIME-version:References:Subject:In-Reply-To:To:From: Date; bh=QGmdfVyMay5+o/rTHPbchVzlOGAie77yTEsfy2/aWwY=; b=BkY8WYI2D5KBOH4j3ogN f4wl8c0CwZ4EsurGgVcTo5lgtUgbn+FbdJg5tz8+4wUJjo5j28CBkUg7ojkz5PT/kknQkn0oPNxXC 0w03f9nNv7zUi1XLzCLKlvdC4AE3dYGVUF63rmfx3C9cGAPqGd+WpbsQybouDnlTBV2LgQgrUikxP 7lIPufqY5pAOZAJmN9+LDG4nNme32Rfy83kzx43zcTuecf0x6KTP3kZv8ZZ7mzrhmMmvY629wfyeT kvJ5AE6YG8eskq6YNUWri3AZxpQZkJwZgL+8l20IGBWNiJJheVSTMORdKJ/R00Yf2rnrIaYX05kSh fIZzDKDWbvKhoQ==; Original-Received: from [87.69.77.57] (port=2930 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nXHBH-00080z-BM; Thu, 24 Mar 2022 02:42:47 -0400 In-Reply-To: <320D86FD-5B2E-4177-9570-A8004A942E8C@acm.org> (message from Mattias =?UTF-8?Q?Engdeg=C3=A5rd?= on Wed, 23 Mar 2022 21:24:16 +0100) 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:228858 Archived-At: > From: Mattias Engdegård > Date: Wed, 23 Mar 2022 21:24:16 +0100 > Cc: Andrew Cohen , 54532@debbugs.gnu.org > > > Can you tell more why this was needed? Emacs has conservative stack marking, so any Lisp object that is referred by some stack-based variable should be protected from GC. Why isn't that enough in this case? > > Because Lisp values are temporarily moved out to a heap allocated buffer which isn't traversed by the stack scanner. `record_unwind_protect_ptr_mark` can be seen as a generalisation of `record_unwind_protect_ptr` (because that's what it is). I understand that these objects are on the heap, but AFAIU a reference to them is on the stack, isn't it? > > Is this really eassume, or is eassert better here? > > No, eassume is appropriate here. It provides more optimisation opportunities. > In fact, most uses of eassert are better or just as good as eassume as long as there are no function calls or tricky memory dereferences. I asked about a specific instance, not in general. That instance was at the end of the function, right before it returns, and I wonder what kind of optimization opportunities that could present.