From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Daniel Colascione Newsgroups: gmane.emacs.devel Subject: Re: Preview: portable dumper Date: Wed, 14 Feb 2018 16:42:08 -0800 Message-ID: <6b691a4b-9eee-b725-b0b5-2440d0c85b9a@dancol.org> References: <047a67ec-9e29-7e4e-0fb0-24c3e59b5886@dancol.org> <83zikjxt1j.fsf@gnu.org> <8360n6ruzu.fsf@gnu.org> <834m2nplmb.fsf@gnu.org> <83inr2oje6.fsf@gnu.org> <83bmwuogfb.fsf@gnu.org> <878trydrbo.fsf@red-bean.com> <87d15jo39q.fsf@ritchie.wxcvbn.org> <26497701-9de7-b91e-7ac3-4fb5949b436e@dancol.org> <83po58yhew.fsf@gnu.org> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit X-Trace: blaine.gmane.org 1518655234 16145 195.159.176.226 (15 Feb 2018 00:40:34 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Thu, 15 Feb 2018 00:40:34 +0000 (UTC) User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.5.0 Cc: emacs-devel@gnu.org To: Philipp Stephani , Eli Zaretskii Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Thu Feb 15 01:40:30 2018 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 1em7az-0003BW-Gc for ged-emacs-devel@m.gmane.org; Thu, 15 Feb 2018 01:40:17 +0100 Original-Received: from localhost ([::1]:48692 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1em7d1-0001ss-EC for ged-emacs-devel@m.gmane.org; Wed, 14 Feb 2018 19:42:23 -0500 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:49341) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1em7cu-0001rU-CV for emacs-devel@gnu.org; Wed, 14 Feb 2018 19:42:17 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1em7ct-00039i-8h for emacs-devel@gnu.org; Wed, 14 Feb 2018 19:42:16 -0500 Original-Received: from dancol.org ([2600:3c01::f03c:91ff:fedf:adf3]:37386) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1em7cs-00039E-VC; Wed, 14 Feb 2018 19:42:15 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=dancol.org; s=x; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:MIME-Version:Date:Message-ID:From:References:Cc:To:Subject; bh=8IySyPLovL4OlfcOCeL4L+LPhlR/iGWSaw6TAovw/2E=; b=aKdEsNmK+7hhRJL5k1S2EOQU+zs+Z0D3K1pSPxokayvbS5ibeAJDiCfGN4YDLcG505FeVNw8kjohesIcSUaia4loxdiPBzXsedvKTs/qggTwptCoieRTvfps82ZJh6kAe8JkDSI1Hv6enRTyYXjgrgKG1qPPhXemSgMq1r8T0qCTUcNnkVvfxLPWtLVsN+Ea9RncB3Z//XXTpgted54VDd5uE75E714iDsKYJMxf/8LNnZVNs3olbQPN3C0Wps/6b9qxCz5rU8RR3Sx/RkPNq3/DVMNEmHIkCApvx30sH+c2Yp79Ag+sLaA0sAfeTcvQvy81FYJqTteFIsCZ94bq+g==; Original-Received: from [2604:4080:1321:8ab0:1c71:c7cb:5303:a013] by dancol.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.84_2) (envelope-from ) id 1em7cr-0004Za-Oq; Wed, 14 Feb 2018 16:42:13 -0800 In-Reply-To: Content-Language: en-US X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2600:3c01::f03c:91ff:fedf:adf3 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:222755 Archived-At: On 02/14/2018 01:03 PM, Philipp Stephani wrote: > > > Eli Zaretskii > schrieb am Di., 13. > Feb. 2018 um 17:39 Uhr: > > > From: Daniel Colascione > > > Date: Mon, 12 Feb 2018 12:18:36 -0800 > > > > I've pushed the portable dumper to the pdumper Savannah branch. It > > should support a fully PIC Emacs. > > Thanks.  I'd urge people to try this branch and report any issues they > see. > > > Got a crash when building on Debian testing. I've attached the output of > 'bt full'. Thanks. There were two bugs, both relating to conservative GC: 1) To make conservative GC work, we record in the dump the start position and Lisp type of each object in the dump. The problem was that we were recording object-start records for objects in the discardable region. With the right stack garbage as input, conservative GC would find one of these object-start records, use it as evidence that it was looking at a real object, then call mark_object, which died because it knows that objects in the discardable region shouldn't be live. Fixed by just not emitting these discardable-region object-start records anymore. 2) When evaluating a Lisp_Object on the stack in mark_maybe_object, occasionally, we can find a word with a valid pointer component but the wrong type tags. Now we check that the Lisp_Object's tagged type matches the actual type of the object in the dump. I don't know why it was so hard to repro these on my machine. I had to bootstrap a few times before Emacs began crashing.