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From: Markus Elfring <Markus.Elfring@web.de>
To: Coccinelle <cocci@systeme.lip6.fr>, git@vger.kernel.org
Cc: "Junio C Hamano" <gitster@pobox.com>, "René Scharfe" <l.s.r@web.de>
Subject: Re: git-coccinelle: adjustments for array.cocci?
Date: Fri, 15 Nov 2019 19:50:49 +0100	[thread overview]
Message-ID: <94301b9c-a397-ae04-c617-92679f4bb018@web.de> (raw)
In-Reply-To: <6fffd13a-738b-e750-9f5a-f0bfb252855b@web.de>

> --- array-released.diff	2019-11-14 21:29:11.020576916 +0100
> +++ array-reduced1.diff	2019-11-14 21:45:58.931956527 +0100
> @@ -6,24 +6,10 @@
>   	r->entry_count = t->entry_count;
>   	r->delta_depth = t->delta_depth;
>  -	memcpy(r->entries,t->entries,t->entry_count*sizeof(t->entries[0]));
> -+	COPY_ARRAY(r->entries, t->entries, t->entry_count);
> ++	memcpy(r->entries,t->entries,t->entry_count*sizeof(*(t->entries)));
>   	release_tree_content(t);
>   	return r;
>   }

It took a while to become more aware of software development challenges
for the safe data processing with the semantic patch language also
at such a source code place.
https://github.com/git/git/blob/3edfcc65fdfc708c1c8f1d314885eecf9beb9b67/fast-import.c#L640

I got the impression that the Coccinelle software is occasionally able
to determine from the search specification “sizeof(T)” the corresponding
data type for code like “*(t->entries)”.
But it seems that there are circumstances to consider where the desired
data type was not automatically determined.
Thus the data processing  can become safer by explicitly expressing
the case distinction for the handling of expressions.

Adjusted transformation rule:
@@
type T;
T* dst_ptr, src_ptr;
T[] dst_arr, src_arr;
expression n, x;
@@
-memcpy
+COPY_ARRAY
       (
(       dst_ptr
|       dst_arr
)
       ,
(       src_ptr
|       src_arr
)
       ,
-       (n) * \( sizeof(T) \| sizeof(*(x)) \)
+       n
       )


Regards,
Markus

  parent reply	other threads:[~2019-11-15 18:51 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 [this message]
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
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

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