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From: "René Scharfe" <l.s.r@web•de>
To: Junio C Hamano <gitster@pobox•com>, Toon Claes <toon@iotcl•com>
Cc: git@vger•kernel.org, Jeff King <peff@peff•net>
Subject: Re: [PATCH 1/2] git-compat-util: introduce MEMZERO_ARRAY() macro
Date: Fri, 12 Dec 2025 14:02:17 +0100	[thread overview]
Message-ID: <f02b628f-b9d7-4436-88ee-3255e02cb0f3@web.de> (raw)
In-Reply-To: <xmqqtsxxg0z4.fsf@gitster.g>

On 12/11/25 4:18 AM, Junio C Hamano wrote:
> Toon Claes <toon@iotcl•com> writes:
> 
>> +@@
>> +- memset(ptr, \( 0x0 \| 0 \), n * \( sizeof(T)
>> +-                                 \| sizeof(*ptr)
>> +-                                 \) )
>> ++ MEMZERO_ARRAY(ptr, n)
> 
> Shouldn't we be also catching
> 
> 	memset(array, '\0', sizeof(array[0]) * ARRAY_SIZE(array));
> 
> in addition to "0" and "0x0"?

Good idea to match "sizeof(ptr[...])", even though we currently don't have
matching code.

Good idea also to match "'\0'".  There's code with that pattern in
compat/regex/.

You can drop "0x0", though, "0" matches it already (at least for me, I have
"spatch version 1.3-dirty compiled with OCaml version 5.1.1" from Homebrew).

If you put parentheses around "n" in the pre-image then Coccinelle will
remove them if present and still match code without them.  They are no
longer needed without the multiplication.  Their removal would improve the
result for ewah/bitmap.c.

René


  reply	other threads:[~2025-12-12 13:02 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-12-10 13:13 [PATCH 0/2] Add MEMZERO_ARRAY() macro and use it in coccinelle Toon Claes
2025-12-10 13:13 ` [PATCH 1/2] git-compat-util: introduce MEMZERO_ARRAY() macro Toon Claes
2025-12-11  3:18   ` Junio C Hamano
2025-12-12 13:02     ` René Scharfe [this message]
2025-12-19  9:17       ` Toon Claes
2025-12-10 13:13 ` [PATCH 2/2] contrib/coccinelle: pass include paths to spatch(1) Toon Claes
2025-12-11  6:19   ` Patrick Steinhardt
2025-12-12  5:04     ` Junio C Hamano
2025-12-13  1:22   ` Junio C Hamano
2025-12-13  0:18 ` [PATCH 0/2] Add MEMZERO_ARRAY() macro and use it in coccinelle Junio C Hamano

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