From: "Stephen J. Turnbull" <stephen@xemacs.org>
To: Stefan Monnier <monnier@iro.umontreal.ca>
Cc: Simon.Marshall@misys.com, emacs-pretest-bug@gnu.org,
Eli Zaretskii <eliz@gnu.org>,
rms@gnu.org, cyd@stupidchicken.com
Subject: [OT] Deugging optimized code (was: [22.1.90]: Point before start of properties)
Date: Sat, 23 Feb 2008 07:20:32 +0900 [thread overview]
Message-ID: <87r6f4hbv3.fsf@uwakimon.sk.tsukuba.ac.jp> (raw)
In-Reply-To: <jwv63whr4vo.fsf-monnier+emacs@gnu.org>
Stefan Monnier writes:
> >> Debugging optimized code is [...] a wrong question.
> > Intel thanks you for your marketing of their future products!
>
> I guess I do, but I don't think you quite understood what I meant:
Oh, I know more about what you do than you seem to think. ;-) A
little bit, but that's enough.
> That's what I meant by "a wrong question": instead of solving the
> impossible debugging problem after-the-fact (after the optimizer
> has done its thing), you can solve a different problem (annotate
> the source program) instead.
First of all, this requires a reproducible problem. That has two
issues: (1) maybe the problem isn't reproducible, and (2) for me at
least reproduction is a waste 90% of the time; the bugs I'm capable of
solving are typically apparent in the stack trace. :-)
Second, you're basically restricting the transformations that are
allowed to the translator. This seems a reasonable strategy to me,
but it's not going to help with Type 2, 3, or 4 bugs, and it may
interfere with Type 1 bugs (eg, if you need to execute a loop a few
billion times to reach the buggy state -- proof of concept strawman).
More Intel The Next Generation promotion. :-)
So I wouldn't go so far as to say the question is "wrong", just that
there are better questions for a lot of debugging problems.
next prev parent reply other threads:[~2008-02-22 22:20 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-02-08 16:35 [22.1.90]: Point before start of properties Marshall, Simon
2008-02-10 3:26 ` Stefan Monnier
2008-02-10 15:22 ` Chong Yidong
2008-02-12 17:52 ` Marshall, Simon
2008-02-12 18:32 ` Stefan Monnier
2008-02-13 10:13 ` Marshall, Simon
2008-02-18 19:52 ` Stefan Monnier
2008-02-19 10:37 ` Marshall, Simon
2008-02-19 16:00 ` Stefan Monnier
2008-02-19 17:23 ` Marshall, Simon
2008-02-19 17:31 ` David Kastrup
2008-02-20 9:44 ` Marshall, Simon
2008-02-19 21:59 ` Stefan Monnier
2008-02-20 11:31 ` Marshall, Simon
2008-02-20 17:17 ` Stefan Monnier
2008-02-20 19:40 ` Eli Zaretskii
2008-02-21 9:16 ` Richard Stallman
2008-02-21 16:02 ` Stefan Monnier
2008-02-22 3:16 ` Stephen J. Turnbull
2008-02-22 15:18 ` [OT] Deugging optimized code (was: [22.1.90]: Point before start of properties) Stefan Monnier
2008-02-22 15:41 ` Andreas Schwab
2008-02-22 22:20 ` Stephen J. Turnbull [this message]
2008-02-22 16:31 ` [22.1.90]: Point before start of properties Eli Zaretskii
2008-02-22 16:27 ` Eli Zaretskii
2008-02-22 22:09 ` Miles Bader
2008-02-23 19:29 ` Richard Stallman
2008-02-23 21:18 ` Eli Zaretskii
2008-02-24 15:22 ` Richard Stallman
2008-02-24 19:59 ` Eli Zaretskii
2008-02-25 10:57 ` Richard Stallman
2008-02-25 15:55 ` Stefan Monnier
2008-02-24 20:36 ` Tom Tromey
2008-02-25 10:57 ` Richard Stallman
2008-02-21 22:27 ` Richard Stallman
[not found] ` <6EE216E1AA959543A555C60FF34FB76702B2DB02@maileube01.misys.global.ad>
2008-02-19 14:45 ` Marshall, Simon
2008-02-19 23:09 ` Richard Stallman
2008-02-10 18:42 ` Richard Stallman
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