From: Stefan Monnier <monnier@iro.umontreal.ca>
To: Dmitry Gutov <dgutov@yandex.ru>
Cc: 15294@debbugs.gnu.org
Subject: bug#15294: 24.3.50; js2-mode parser is several times slower in lexical-binding mode
Date: Thu, 12 Sep 2013 23:40:45 -0400 [thread overview]
Message-ID: <jwvhadps8a1.fsf-monnier+emacs@gnu.org> (raw)
In-Reply-To: <jwvzjrly386.fsf-monnier+emacs@gnu.org> (Stefan Monnier's message of "Mon, 09 Sep 2013 22:04:38 -0400")
> In the compiled case, loading js2-mode-lexical.elc and then redefining
> `js2-get-token' to the value it has in js2-mode-dynamic.elc brings me
> back the same speed as with js2-mode-dynamic.elc.
> IOW the slowdown is in js2-get-token.
It seems the slowdown is indeed linked to the way `catch' is handled
(indeed, this non-idiomatic ELisp code ends up byte-compiled in a really
poor way).
The trivial patch below brings the time down from 5s to 2.6s (as
compared to 2.1s for the dynamic-binding version).
Stefan
diff --git a/packages/js2-mode/js2-mode.el b/packages/js2-mode/js2-mode.el
index 3568f18..1d76469 100644
--- a/packages/js2-mode/js2-mode.el
+++ b/packages/js2-mode/js2-mode.el
@@ -5310,10 +5311,10 @@ corresponding number. Otherwise return -1."
(defun js2-get-token ()
"Return next JavaScript token, an int such as js2-RETURN."
- (let (c c1 identifier-start is-unicode-escape-start
- contains-escape escape-val str result base
- is-integer quote-char val look-for-slash continue)
- (catch 'return
+ (catch 'return
+ (let (c c1 identifier-start is-unicode-escape-start
+ contains-escape escape-val str result base
+ is-integer quote-char val look-for-slash continue)
(while t
;; Eat whitespace, possibly sensitive to newlines.
(setq continue t)
next prev parent reply other threads:[~2013-09-13 3:40 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-06 20:59 bug#15294: 24.3.50; js2-mode parser is several times slower in lexical-binding mode Dmitry Gutov
2013-09-06 23:44 ` Xue Fuqiao
2013-09-07 3:15 ` Stefan Monnier
2013-09-08 22:32 ` Stefan Monnier
2013-09-10 2:04 ` Stefan Monnier
2013-09-13 3:40 ` Stefan Monnier [this message]
2013-09-13 3:59 ` Drew Adams
2013-09-13 4:37 ` Stefan Monnier
2013-09-13 5:45 ` Drew Adams
2013-09-13 13:01 ` Stefan Monnier
2013-09-14 0:09 ` Lexical let and setq Michael Welsh Duggan
2013-09-14 3:46 ` Stefan Monnier
2013-09-14 11:13 ` Lars Magne Ingebrigtsen
2013-09-14 14:04 ` Pascal J. Bourguignon
2013-09-15 5:11 ` Stefan Monnier
2013-09-14 21:47 ` Richard Stallman
2013-09-15 5:09 ` Stefan Monnier
2013-09-15 16:54 ` Richard Stallman
2013-09-15 17:06 ` Stefan Monnier
2013-09-16 10:47 ` Richard Stallman
2013-09-14 4:20 ` bug#15294: 24.3.50; js2-mode parser is several times slower in lexical-binding mode Dmitry Gutov
2013-09-14 14:27 ` Stefan Monnier
2013-09-15 0:11 ` Dmitry Gutov
2013-09-15 5:04 ` Stefan Monnier
2013-09-15 16:54 ` Richard Stallman
2013-09-15 0:24 ` Dmitry Gutov
2013-09-15 5:06 ` Stefan Monnier
2013-09-18 23:48 ` Stefan Monnier
2013-09-22 4:56 ` Dmitry Gutov
2013-10-03 5:00 ` Stefan Monnier
2013-10-04 2:38 ` Dmitry Gutov
2013-10-04 13:52 ` Stefan Monnier
2013-10-05 3:27 ` Dmitry Gutov
2014-12-14 12:31 ` Dmitry Gutov
2014-12-14 14:08 ` Stefan Monnier
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