git@vger.kernel.org mailing list mirror (one of many)
 help / color / mirror / code / Atom feed
From: Markus Elfring <Markus.Elfring@web.de>
To: "René Scharfe" <l.s.r@web.de>, git@vger.kernel.org
Subject: Re: coccinelle: improve array.cocci
Date: Wed, 20 Nov 2019 10:01:04 +0100	[thread overview]
Message-ID: <d053612d-107b-fdb2-b722-6455ef068239@web.de> (raw)
In-Reply-To: <d291ec11-c0f3-2918-193d-49fcbd65a18e@web.de>

> I like that COPY_ARRAY and MOVE_ARRAY are handled in the same rule,
> as they share the same parameters and do the same -- except that
> the latter handles overlaps, while the former may be a bit faster.
>
> And I like that it's short.

Thanks for such positive feedback after our growing discussion.


> I don't like that ALLOC_ARRAY is handled in the same rule, as it is
> quite different from the other two macros.

This case distinction can share a few metavariables with the other
transformation approach, can't it?


> Coccinelle needs significantly longer to apply the new version.

This can happen because of a more complete source code search pattern,
can't it?

The data processing can benefit from parallelisation (if desired.)
https://github.com/coccinelle/coccinelle/blob/66a1118e04a6aaf1acdae89623313c8e05158a8d/docs/manual/spatch_options.tex#L745


> Here are times for master:

The SmPL script execution times can be analysed also directly with
the help of the Coccinelle software by profiling functionality.
https://github.com/coccinelle/coccinelle/blob/66a1118e04a6aaf1acdae89623313c8e05158a8d/docs/manual/spatch_options.tex#L736


> ... and here with the patch applied:
>
> Benchmark #1: make contrib/coccinelle/array.cocci.patch
>   Time (mean ± σ):     43.420 s ±  0.490 s    [User: 43.087 s, System: 0.273 s]

I got an other distribution of run times on my test system.


> The current version checks if source and destination are of the same type,
> and whether the sizeof operand is either said type or an element of source
> or destination.

The specification of metavariables for pointer types has got some consequences.


> The new one does not.

I suggest to use a search for (pointer) expressions instead.
This approach can trigger other consequences then.


> So I don't see claim 4 ("Increase the precision") fulfilled,

I tried to express an adjustment on the change granularity by the plus
and minus characters at the beginning of the lines in the semantic patch.

The SmPL disjunctions provide also more common functionality now.


> quite the opposite rather.

The search for compatible pointers can become even more challenging.


> I think an automatic transformation should only be generated if it is safe.

Different expectations can occur around safety and change convenience.

Would you eventually work with SmPL script variants in parallel according
to different confidence settings?


> It's hard to spot a weird case in a generated patch amid ten
> well-behaving ones.

I can follow also this development concern to some degree.

Regards,
Markus

  reply	other threads:[~2019-11-20  9:01 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-12 15:08 coccinelle: adjustments for array.cocci? Markus Elfring
2019-11-12 18:37 ` René Scharfe
2019-11-13  2:11   ` Junio C Hamano
2019-11-13  8:49     ` Markus Elfring
2019-11-14  2:03       ` Junio C Hamano
2019-11-14 13:15         ` Markus Elfring
2019-11-14 16:41           ` René Scharfe
2019-11-14 17:14             ` Markus Elfring
2019-11-14 17:46               ` René Scharfe
2019-11-15 11:11                 ` git-coccinelle: " Markus Elfring
2019-11-15 14:20                   ` Markus Elfring
2019-11-15 18:50                   ` Markus Elfring
2019-11-16  1:00                     ` [Cocci] " Julia Lawall
2019-11-16  6:57                       ` Markus Elfring
2019-11-16  8:29                       ` Markus Elfring
2019-11-16 17:57                   ` Julia Lawall
2019-11-16 18:29                     ` Markus Elfring
2019-11-15 20:37   ` coccinelle: " Markus Elfring
2019-11-16 21:13     ` René Scharfe
2019-11-17  7:56       ` Markus Elfring
2019-11-17 13:40         ` René Scharfe
2019-11-17 18:19           ` Markus Elfring
2019-11-19 19:14             ` René Scharfe
2019-11-19 20:21               ` Markus Elfring
2019-11-21 19:01                 ` René Scharfe
2019-11-16 16:33   ` Markus Elfring
2019-11-16 21:38     ` René Scharfe
2019-11-17  8:19       ` Markus Elfring
2019-11-17 13:40         ` René Scharfe
2019-11-17 18:36           ` Markus Elfring
2019-11-19 19:15             ` René Scharfe
2019-11-18 16:10           ` [PATCH] coccinelle: improve array.cocci Markus Elfring
2019-11-19 19:15             ` René Scharfe
2019-11-20  9:01               ` Markus Elfring [this message]
2019-11-21 19:02                 ` René Scharfe
2019-11-21 19:44                   ` Markus Elfring
2019-11-22 15:29                     ` SZEDER Gábor
2019-11-22 16:17                       ` Markus Elfring
2019-11-22  5:54               ` [PATCH] " Junio C Hamano
2019-11-22  7:34                 ` Markus Elfring
2020-01-25  8:23             ` Markus Elfring

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

  List information: http://vger.kernel.org/majordomo-info.html

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=d053612d-107b-fdb2-b722-6455ef068239@web.de \
    --to=markus.elfring@web.de \
    --cc=git@vger.kernel.org \
    --cc=l.s.r@web.de \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
Code repositories for project(s) associated with this public inbox

	https://80x24.org/mirrors/git.git

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).