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Re: Emacs Lisp JIT Compiler
From: |
Tom Tromey |
Subject: |
Re: Emacs Lisp JIT Compiler |
Date: |
Mon, 13 Aug 2018 09:15:38 -0600 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/26.1.50 (gnu/linux) |
>>>>> "Paul" == Paul Eggert <address@hidden> writes:
Paul> When you say "doesn't work", does that mean Emacs can reliably tell
Paul> the JIT won't work and fall back on the current bytecode
Paul> implementation, or something else?
What I meant is that when I wrote this, I didn't think about
--with-wide-int, and so some of the calls into libjit are incorrect for
that situation. It shouldn't be hard to fix.
>> libjit never frees functions. So, if a function is JIT-compiled
>> and then redefined, the old JIT code will linger. It's possible to fix
>> this with a custom allocator and a libjit patch (that I sent but that
>> hasn't been checked in yet).
Paul> libjit has only one committer, Aleksey, and no commits since March. Is
Paul> there a bottleneck there?
He's reasonably responsive, but it's true that the lack of an active
community around libjit is a bit of a risk. Mostly the problems would
be either (1) missing ports or (2) lack of improvements; for example,
libjit's register allocator is not very good, but nobody is working on
improving it.
It would be possible to switch to another JIT back end, but when I
looked into the various ones that are available, libjit was both easy to
use and reasonably lightweight (without being too lightweight, like GNU
Lightning).
But, for example, GCC has a JIT interface now. That could be used instead.
That seemed pretty heavy-weight to me; but I didn't really try it in
anger so maybe my fears are unfounded.
Tom
- Emacs Lisp JIT Compiler, Tom Tromey, 2018/08/13
- Re: Emacs Lisp JIT Compiler, Paul Eggert, 2018/08/13
- Re: Emacs Lisp JIT Compiler,
Tom Tromey <=
- Re: Emacs Lisp JIT Compiler, Tom Tromey, 2018/08/13
- Re: Emacs Lisp JIT Compiler, Daniel Colascione, 2018/08/14
- Re: Emacs Lisp JIT Compiler, Paul Eggert, 2018/08/14
- Re: Emacs Lisp JIT Compiler, Daniel Colascione, 2018/08/14
- Re: Emacs Lisp JIT Compiler, Paul Eggert, 2018/08/14
- Re: Emacs Lisp JIT Compiler, Eli Zaretskii, 2018/08/15
- Re: Emacs Lisp JIT Compiler, Paul Eggert, 2018/08/15
- Re: Emacs Lisp JIT Compiler, Eli Zaretskii, 2018/08/15
- Re: Emacs Lisp JIT Compiler, Tom Tromey, 2018/08/15
- Re: Emacs Lisp JIT Compiler, Eli Zaretskii, 2018/08/16