From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.bugs Subject: bug#10164: 24.0.91; Instant crash enabling linum-mode Date: Wed, 30 Nov 2011 08:54:41 -0500 Message-ID: References: <4ED58F60.4000604@code-affinity.com> Reply-To: Eli Zaretskii NNTP-Posting-Host: lo.gmane.org X-Trace: dough.gmane.org 1322661318 17705 80.91.229.12 (30 Nov 2011 13:55:18 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Wed, 30 Nov 2011 13:55:18 +0000 (UTC) Cc: 10164@debbugs.gnu.org, tim.crews@code-affinity.com To: Dan Nicolaescu Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Wed Nov 30 14:55:13 2011 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([140.186.70.17]) by lo.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1RVkcz-0002dB-1J for geb-bug-gnu-emacs@m.gmane.org; Wed, 30 Nov 2011 14:55:13 +0100 Original-Received: from localhost ([::1]:60923 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RVkcy-0007mu-MZ for geb-bug-gnu-emacs@m.gmane.org; Wed, 30 Nov 2011 08:55:12 -0500 Original-Received: from eggs.gnu.org ([140.186.70.92]:43908) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RVkcr-0007jO-IY for bug-gnu-emacs@gnu.org; Wed, 30 Nov 2011 08:55:10 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RVkcl-0001D2-L2 for bug-gnu-emacs@gnu.org; Wed, 30 Nov 2011 08:55:05 -0500 Original-Received: from debbugs.gnu.org ([140.186.70.43]:45282) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RVkcl-0001Cy-7m for bug-gnu-emacs@gnu.org; Wed, 30 Nov 2011 08:54:59 -0500 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.69) (envelope-from ) id 1RVkco-0008IB-4F for bug-gnu-emacs@gnu.org; Wed, 30 Nov 2011 08:55:02 -0500 X-Loop: help-debbugs@gnu.org Resent-From: Eli Zaretskii Original-Sender: debbugs-submit-bounces@debbugs.gnu.org Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Wed, 30 Nov 2011 13:55:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 10164 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: Original-Received: via spool by 10164-submit@debbugs.gnu.org id=B10164.132266128831851 (code B ref 10164); Wed, 30 Nov 2011 13:55:02 +0000 Original-Received: (at 10164) by debbugs.gnu.org; 30 Nov 2011 13:54:48 +0000 Original-Received: from localhost ([127.0.0.1] helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1RVkca-0008Hg-0K for submit@debbugs.gnu.org; Wed, 30 Nov 2011 08:54:48 -0500 Original-Received: from fencepost.gnu.org ([140.186.70.10]) by debbugs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1RVkcX-0008HX-Al for 10164@debbugs.gnu.org; Wed, 30 Nov 2011 08:54:46 -0500 Original-Received: from eliz by fencepost.gnu.org with local (Exim 4.71) (envelope-from ) id 1RVkcT-0005os-HE; Wed, 30 Nov 2011 08:54:41 -0500 In-reply-to: (message from Dan Nicolaescu on Wed, 30 Nov 2011 07:52:40 -0500) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.11 Precedence: list Resent-Date: Wed, 30 Nov 2011 08:55:02 -0500 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6 (newer, 2) X-Received-From: 140.186.70.43 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.org@gnu.org Original-Sender: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.bugs:54476 Archived-At: > From: Dan Nicolaescu > Cc: Tim Crews , 10164@debbugs.gnu.org > Date: Wed, 30 Nov 2011 07:52:40 -0500 > > Eli Zaretskii writes: > > >> Date: Tue, 29 Nov 2011 19:05:20 -0700 > >> From: Tim Crews > >> > >> Start Emacs with runemacs -Q --no-init-file > >> C-x C-f foo.txt > >> M-x linum-mode > >> (Emacs doesn't crash yet) > >> Type anything. Emacs instantly crashes. > > > > Arrgh! This is GCC 4.6.x "as-is" code reordering in action. Emacs > > crashes here: > > > > xassert (!row->enabled_p > > || row->mode_line_p > > || verify_row_hash (row)); > > > > Evidently, it calls verify_row_hash before it tests row->mode_line_p. > > Are you sure? How else can I explain this display from GDB: (gdb) prow y=0 x=0 pwid=673 a+d=12+4=16 phys=12+4=16 vis=16 used=(LMargin=0,Text=84,RMargin=0) Hash=263825844 start=0 end=0 ENA MODEL ? MODEL says that this row has its mode_line_p flag set. Just to be sure, I ran the recipe again under GDB, setting a breakpoint inside verify_row_hash thusly: (gdb) break verify_row_hash if row->mode_line_p != 0 and sure enough, it breaks as soon as I turn on linum-mode, with ROW that shows the glyphs in the mode line. > Without interprocedural analysis the compiler cannot know > that `verify_row_hash' does not alter row->enabled_p, so it cannot > change the evaluation order. I don't know. Maybe GCC does perform such an analysis. Or maybe it decides that the result of this comparison in verify_row_hash: row->hash == row_hash (row) will not change even if row_hash does modify its argument ROW. Or maybe it's a bug in GCC.