From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.devel Subject: Re: Conservative GC isn't safe Date: Mon, 28 Nov 2016 21:37:47 +0200 Message-ID: <8337ibz984.fsf@gnu.org> References: <66485157-00cd-4704-a421-cbfe84299cae@cs.ucla.edu> <69a1fdf3-7120-125b-8556-d74f5afc6b37@dancol.org> <8360na399k.fsf@gnu.org> <26a81224-c61e-27ac-37b4-5e7bd1e90910@dancol.org> Reply-To: Eli Zaretskii NNTP-Posting-Host: blaine.gmane.org X-Trace: blaine.gmane.org 1480361934 21694 195.159.176.226 (28 Nov 2016 19:38:54 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Mon, 28 Nov 2016 19:38:54 +0000 (UTC) Cc: monnier@iro.umontreal.ca, emacs-devel@gnu.org To: Daniel Colascione Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Mon Nov 28 20:38:44 2016 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1cBRlD-00044C-Uc for ged-emacs-devel@m.gmane.org; Mon, 28 Nov 2016 20:38:44 +0100 Original-Received: from localhost ([::1]:60784 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cBRlH-0004bU-QR for ged-emacs-devel@m.gmane.org; Mon, 28 Nov 2016 14:38:47 -0500 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:55216) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cBRkg-0004bO-OK for emacs-devel@gnu.org; Mon, 28 Nov 2016 14:38:11 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cBRkd-0003Z4-9l for emacs-devel@gnu.org; Mon, 28 Nov 2016 14:38:10 -0500 Original-Received: from fencepost.gnu.org ([2001:4830:134:3::e]:47667) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cBRkd-0003Yz-6z; Mon, 28 Nov 2016 14:38:07 -0500 Original-Received: from 84.94.185.246.cable.012.net.il ([84.94.185.246]:3746 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_128_CBC_SHA1:128) (Exim 4.82) (envelope-from ) id 1cBRkX-0005vY-HT; Mon, 28 Nov 2016 14:38:06 -0500 In-reply-to: (message from Daniel Colascione on Mon, 28 Nov 2016 11:18:32 -0800) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 2001:4830:134:3::e 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:209677 Archived-At: > From: Daniel Colascione > Date: Mon, 28 Nov 2016 11:18:32 -0800 > Cc: emacs-devel@gnu.org > > Let me ask again: we already have all the runtime data we need for more > conservative GC. Where is the resistance to the idea coming from? I already answered that up-thread: it will be dead code, and thus will likely do the wrong thing if it ever runs. I also suggested what to do instead: add assertions that express what we believe should never happen. Stefan says doing that is unlikely to be justified by the dangers, but if we think so, then we shouldn't be afraid of the problem in the first place. If we are, then adding assertions is the way to go.