From: Johannes Schindelin <Johannes.Schindelin@gmx.de>
To: "René Scharfe" <l.s.r@web.de>
Cc: Git List <git@vger.kernel.org>, Junio C Hamano <gitster@pobox.com>
Subject: Re: [PATCH] fast-export: avoid NULL pointer arithmetic
Date: Wed, 9 May 2018 17:43:30 -0400 (DST) [thread overview]
Message-ID: <nycvar.QRO.7.76.6.1805091743080.77@tvgsbejvaqbjf.bet> (raw)
In-Reply-To: <d50a4d5d-3b99-453e-1b52-4e733453fb78@web.de>
[-- Attachment #1: Type: text/plain, Size: 899 bytes --]
Hi René,
On Wed, 9 May 2018, René Scharfe wrote:
> Clang 6 reports the following warning, which is turned into an error in a
> DEVELOPER build:
>
> builtin/fast-export.c:162:28: error: performing pointer arithmetic on a null pointer has undefined behavior [-Werror,-Wnull-pointer-arithmetic]
> return ((uint32_t *)NULL) + mark;
> ~~~~~~~~~~~~~~~~~~ ^
> 1 error generated.
>
> The compiler is correct, and the error message speaks for itself. There
> is no need for any undefined operation -- just cast mark to void * or
> uint32_t after an intermediate cast to uintptr_t. That encodes the
> integer value into a pointer and later decodes it as intended.
>
> While at it remove an outdated comment -- intptr_t has been used since
> ffe659f94d (parse-options: make some arguments optional, add callbacks),
> committed in October 2007.
ACK.
Thanks,
Dscho
next prev parent reply other threads:[~2018-05-09 21:43 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-09 21:06 [PATCH] fast-export: avoid NULL pointer arithmetic René Scharfe
2018-05-09 21:43 ` Johannes Schindelin [this message]
2018-05-10 9:24 ` René Scharfe
2018-05-10 10:51 ` Junio C Hamano
2018-05-10 19:47 ` René Scharfe
2018-05-11 2:16 ` Junio C Hamano
2018-05-11 4:49 ` Junio C Hamano
2018-05-11 6:19 ` Duy Nguyen
2018-05-11 8:56 ` Jeff King
2018-05-11 13:11 ` Duy Nguyen
2018-05-11 13:34 ` Duy Nguyen
2018-05-11 17:42 ` Jeff King
2018-05-12 8:45 ` René Scharfe
2018-05-12 8:49 ` René Scharfe
2018-05-14 1:37 ` Junio C Hamano
2018-05-15 19:36 ` René Scharfe
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