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bug#15294: 24.3.50; js2-mode parser is several times slower in lexical-b
From: |
Stefan Monnier |
Subject: |
bug#15294: 24.3.50; js2-mode parser is several times slower in lexical-binding mode |
Date: |
Mon, 09 Sep 2013 22:04:38 -0400 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/24.3.50 (gnu/linux) |
> If I append -*- lexical-binding: t -*- to the first line of js2-mode.el
> and eval the buffer, parsing a file takes several (3 to 4) times longer.
[ I'm disregarding the interpreted time for now, since the issues are
likely to be different. ]
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.
If it indeed comes from the handling of catch/throw, then there are two
ways to fix it:
- provide a new byte-code for catch which does not require wrapping the
body in a closure. This should not be terribly difficult and would
benefit all existing code, but it does require changes to the way
catch is implemented.
- improve the byte-compiler so it can compile away cl-block/cl-return.
This should not require new byte-codes, but requires delving "deepish"
into the byte-compiler.
Stefan
- bug#15294: 24.3.50; js2-mode parser is several times slower in lexical-binding mode, Dmitry Gutov, 2013/09/06
- bug#15294: 24.3.50; js2-mode parser is several times slower in lexical-binding mode, Dmitry Gutov, 2013/09/14
- bug#15294: 24.3.50; js2-mode parser is several times slower in lexical-binding mode, Stefan Monnier, 2013/09/14
- bug#15294: 24.3.50; js2-mode parser is several times slower in lexical-binding mode, Dmitry Gutov, 2013/09/14
- bug#15294: 24.3.50; js2-mode parser is several times slower in lexical-binding mode, Stefan Monnier, 2013/09/15
- bug#15294: 24.3.50; js2-mode parser is several times slower in lexical-binding mode, Richard Stallman, 2013/09/15