From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: David Welch Newsgroups: gmane.emacs.bugs Subject: bug#30849: 27.0.50; CC-mode: very slow when parsing big C array initializer Date: Tue, 20 Mar 2018 22:08:21 +0000 Message-ID: References: , <20180320194843.GA5165@ACM> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="_000_AM5P18901MB0193042603FE2B4D038A589AF8AB0AM5P18901MB0193_" X-Trace: blaine.gmane.org 1521583633 6641 195.159.176.226 (20 Mar 2018 22:07:13 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Tue, 20 Mar 2018 22:07:13 +0000 (UTC) Cc: "30849@debbugs.gnu.org" <30849@debbugs.gnu.org> To: Alan Mackenzie Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Tue Mar 20 23:07:08 2018 Return-path: Envelope-to: geb-bug-gnu-emacs@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 1eyPPP-0001at-0z for geb-bug-gnu-emacs@m.gmane.org; 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charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable > Seeing as how you're using master, would you please pull this change > into your copy of the repository, and see if you agree with me that it > fixes this bug. > Yes, thanks. That fixes the slow down for me. ________________________________ From: Alan Mackenzie Sent: 20 March 2018 19:48 To: David Welch Cc: 30849@debbugs.gnu.org Subject: Re: bug#30849: 27.0.50; CC-mode: very slow when parsing big C arra= y initializer Hello, David. On Sun, Mar 18, 2018 at 18:04:55 +0000, David Welch wrote: > Run 'emacs -Q bar.c' (this file is attached) > Goto a line inside the initializer e.g. 'M-x goto-line RET 9522' > emacs will hang for ~50 seconds on a 100% cpu on a Intel i7 @ 3.40GHz. Yes. This isn't good. > This bug seems to be introduced by > commit d3090a3a3e22c4b0f4e0e833942f5942eb392c51 (HEAD, refs/bisect/bad) > Author: Alan Mackenzie > Date: Fri Feb 2 20:46:35 2018 +0000 > CC Mode: Fix an enum intro being parsed as defun-block-intro > > * lisp/progmodes/cc-engine.el (c-inside-bracelist-p): Return a bufpos= rather > than t for the enum case. > (c-add-stmt-syntax, c-guess-continued-construct): Replace > c-looking-at-or-maybe-in-bracelist by c-inside-bracelist-p, since the= former > does not recognize enum brace lists, but the latter does. > > * lisp/progmodes/cc-fonts.el (c-get-fontification-context): Replace > c-looking-at-or-maybe-in-bracelist by c-inside-bracelist-p. > I generated a profile and 95% of time is spent in c-inside-bracelist-p > called from c-get-fontification-context. Thanks for taking the trouble to report this, and thanks for researching the cause. I think this bug is a duplicate of bug #30367, for which I've just committed commit 16559146f9db1b36d5e8b6c92edb5bb36fafdb85 to savannah. (Thanks for giving me a nudge, here.) > In GNU Emacs 27.0.50 (build 2, x86_64-pc-linux-gnu, GTK+ Version 3.22.25) > of 2018-03-17 built on lgw01-amd64-055 > Windowing system distributor 'The X.Org Foundation', version 11.0.1180300= 0 > System Description: Ubuntu 17.10 Bear in mind that in such an unusual source file (with a ~17,500 line array initialisation), CC Mode is going to take some time to analyse things. But taking nearly a minute to draw a screen is outside the bounds of acceptability. -- Alan Mackenzie (Nuremberg, Germany). --_000_AM5P18901MB0193042603FE2B4D038A589AF8AB0AM5P18901MB0193_ Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

> Seeing as how you're using master, would you please pu= ll this change
> into your copy of the repository, and see if you agree with me that it=
> fixes this bug.

>

Yes, thanks. That fixes the slow = down for me.


From: Alan Mackenzie <= acm@muc.de>
Sent: 20 March 2018 19:48
To: David Welch
Cc: 30849@debbugs.gnu.org
Subject: Re: bug#30849: 27.0.50; CC-mode: very slow when parsing big= C array initializer
 
Hello, David.

On Sun, Mar 18, 2018 at 18:04:55 +0000, David Welch wrote:

> Run 'emacs -Q bar.c' (this file is attached)
> Goto a line inside the initializer e.g. 'M-x goto-line RET 9522'
> emacs will hang for ~50 seconds on a 100% cpu on a Intel i7 @ 3.40GHz.=

Yes.  This isn't good.

> This bug seems to be introduced by

> commit d3090a3a3e22c4b0f4e0e833942f5942eb392c51 (HEAD, refs/bisect/bad= )
> Author: Alan Mackenzie <acm@muc.de>
> Date:   Fri Feb 2 20:46:35 2018 +0000

>     CC Mode: Fix an enum intro being parsed as defun-bl= ock-intro
>     
>     * lisp/progmodes/cc-engine.el (c-inside-bracelist-p= ): Return a bufpos rather
>     than t for the enum case.
>     (c-add-stmt-syntax, c-guess-continued-construct): R= eplace
>     c-looking-at-or-maybe-in-bracelist by c-inside-brac= elist-p, since the former
>     does not recognize enum brace lists, but the latter= does.
>     
>     * lisp/progmodes/cc-fonts.el (c-get-fontification-c= ontext): Replace
>     c-looking-at-or-maybe-in-bracelist by c-inside-brac= elist-p.

> I generated a profile and 95% of time is spent in c-inside-bracelist-p=
> called from c-get-fontification-context.

Thanks for taking the trouble to report this, and thanks for researching the cause.

I think this bug is a duplicate of bug #30367, for which I've just
committed commit 16559146f9db1b36d5e8b6c92edb5bb36fafdb85 to savannah.
(Thanks for giving me a nudge, here.)

> In GNU Emacs 27.0.50 (build 2, x86_64-pc-linux-gnu, GTK+ Version 3= .22.25)
>  of 2018-03-17 built on lgw01-amd64-055
> Windowing system distributor 'The X.Org Foundation', version 11.0.1180= 3000
> System Description: Ubuntu 17.10



Bear in mind that in such an unusual source file (with a ~17,500 line
array initialisation), CC Mode is going to take some time to analyse
things.  But taking nearly a minute to draw a screen is outside the bounds of acceptability.

--
Alan Mackenzie (Nuremberg, Germany).
--_000_AM5P18901MB0193042603FE2B4D038A589AF8AB0AM5P18901MB0193_--