From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.bugs Subject: bug#15294: 24.3.50; js2-mode parser is several times slower in lexical-binding mode Date: Fri, 13 Sep 2013 00:37:25 -0400 Message-ID: References: <871u51ll93.fsf@yandex.ru> <0b29ebee-8ed4-47e2-816b-910a013a0898@default> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1379047106 12893 80.91.229.3 (13 Sep 2013 04:38:26 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Fri, 13 Sep 2013 04:38:26 +0000 (UTC) Cc: 15294@debbugs.gnu.org, Dmitry Gutov To: Drew Adams Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Fri Sep 13 06:38:28 2013 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1VKL9B-0001Nb-NP for geb-bug-gnu-emacs@m.gmane.org; Fri, 13 Sep 2013 06:38:21 +0200 Original-Received: from localhost ([::1]:44744 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VKL9B-0006rN-Ai for geb-bug-gnu-emacs@m.gmane.org; Fri, 13 Sep 2013 00:38:21 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:60323) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VKL91-0006qN-1W for bug-gnu-emacs@gnu.org; Fri, 13 Sep 2013 00:38:18 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VKL8t-0006di-Nl for bug-gnu-emacs@gnu.org; Fri, 13 Sep 2013 00:38:10 -0400 Original-Received: from debbugs.gnu.org ([140.186.70.43]:52132) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VKL8t-0006de-KQ for bug-gnu-emacs@gnu.org; Fri, 13 Sep 2013 00:38:03 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.80) (envelope-from ) id 1VKL8t-0000JH-0g for bug-gnu-emacs@gnu.org; Fri, 13 Sep 2013 00:38:03 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Stefan Monnier Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Fri, 13 Sep 2013 04:38:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 15294 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: Original-Received: via spool by 15294-submit@debbugs.gnu.org id=B15294.13790470571156 (code B ref 15294); Fri, 13 Sep 2013 04:38:02 +0000 Original-Received: (at 15294) by debbugs.gnu.org; 13 Sep 2013 04:37:37 +0000 Original-Received: from localhost ([127.0.0.1]:60425 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1VKL8R-0000IZ-K2 for submit@debbugs.gnu.org; Fri, 13 Sep 2013 00:37:36 -0400 Original-Received: from ironport2-out.teksavvy.com ([206.248.154.182]:50031) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1VKL8O-0000IH-8R for 15294@debbugs.gnu.org; Fri, 13 Sep 2013 00:37:32 -0400 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: Av8EABK/CFG4rxBo/2dsb2JhbABEuzWDWRdzgh4BAQQBViMFCws0EhQYDSSIHgbBLZEKA6R6gV6DEw X-IPAS-Result: Av8EABK/CFG4rxBo/2dsb2JhbABEuzWDWRdzgh4BAQQBViMFCws0EhQYDSSIHgbBLZEKA6R6gV6DEw X-IronPort-AV: E=Sophos;i="4.84,565,1355115600"; d="scan'208";a="27591528" Original-Received: from 184-175-16-104.dsl.teksavvy.com (HELO pastel.home) ([184.175.16.104]) by ironport2-out.teksavvy.com with ESMTP/TLS/ADH-AES256-SHA; 13 Sep 2013 00:33:54 -0400 Original-Received: by pastel.home (Postfix, from userid 20848) id A779662E78; Fri, 13 Sep 2013 00:37:25 -0400 (EDT) In-Reply-To: <0b29ebee-8ed4-47e2-816b-910a013a0898@default> (Drew Adams's message of "Thu, 12 Sep 2013 20:59:52 -0700 (PDT)") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3.50 (gnu/linux) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.15 Precedence: list X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x 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:78313 Archived-At: > Or is the byte compiler likely to be improved in this regard, so users > need not be aware of it and take measures manually? As indicated in the FIXMEs I added in src/bytecode.c at the time, the current byte codes for unwind-protect, condition-case, and catch are very inefficient for lexical-binding code. I do hope to fix those issues by introducing other byte-codes which will let us generate significantly more efficient code for those constructs, but in 24.1, the priority was to get lexical-binding to work correctly, performance being a secondary concern (tho for most idiomatic Elisp code, the performance tends to be competitive). What people should know is that (let (x y z) ...(setq x ...) ...(setq z ...) ...(setq y ...) is often a bad idea in Elisp, and even more so in lexical-binding code (in some cases, if a variable is immutable it can be handled significantly more efficiently, so the mere existence of a single `setq' on a variable can sometimes slow other chunks of code: in many cases `let' is cheaper than `setq'). Stefan