From: Derek M Jones <derek@knosof.co.uk>
To: Christopher Li <sparse@chrisli.org>
Cc: David Given <dg@cowlark.com>, linux-sparse@vger.kernel.org
Subject: Re: [PATCH 7/16] Let void have sizeof 1
Date: Thu, 25 Dec 2008 00:14:50 +0000 [thread overview]
Message-ID: <4952D07A.6090900@knosof.co.uk> (raw)
In-Reply-To: <70318cbf0812241510o2318f701w938840b9123fb9e4@mail.gmail.com>
Christopher,
> I don't see the kernel directly use sizeof(void). Most of the place is
In some places it uses sizeof(*void_ptr) and I don't think we want to
prohibit a usage that is consistent with how void_ptr can be
manipulated.
> using (void*) pointer + offset. It is not portable. But it is probably not
> worthy while to fix. Convert the void* to char*, add offset, convert it back
> to void* is pretty annoying as well. If we really want to make it clean, maybe
> we can use a macro or inline functions. Again, probably not worth the effort.
I agree. However, we need to recognise that this hole that has been
put into the type system needs to be carefully monitored to make
sure that unintended consequences do not occur. Hence my suggestion
that sparse check for suspicious usage, but the only one I have come
up with so far is a sequence of conversions that is equivalent to:
(char*)((void *)ch_ptr + offset)
--
Derek M. Jones tel: +44 (0) 1252 520 667
Knowledge Software Ltd mailto:derek@knosof.co.uk
Source code analysis http://www.knosof.co.uk
next prev parent reply other threads:[~2008-12-25 0:15 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-12-18 21:51 [PATCH 00/16] More patches Alexey Zaytsev
2008-12-18 21:51 ` [PATCH 01/16] Add enum member list to the parent Alexey Zaytsev
2008-12-18 21:51 ` [PATCH 02/16] Expand "dubious !x & y" handling to other combinations of !, &, and | Alexey Zaytsev
2008-12-18 21:52 ` [PATCH 03/16] Set gcc include path at runtime Alexey Zaytsev
2008-12-18 21:52 ` [PATCH 04/16] Let cgcc pass -gcc-base-dir to sparse Alexey Zaytsev
2008-12-18 21:52 ` [PATCH 05/16] Document -gcc-base-dir in sparse.1 Alexey Zaytsev
2008-12-18 21:52 ` [PATCH 06/16] Rename dirafter to idirafter Alexey Zaytsev
2008-12-18 22:32 ` [PATCH 7/16] Let void have sizeof 1 Alexey Zaytsev
2008-12-23 3:51 ` Christopher Li
2008-12-23 4:37 ` Alexey Zaytsev
2008-12-23 5:29 ` Alexey Zaytsev
2008-12-23 9:00 ` Derek M Jones
2008-12-23 15:05 ` Alexey Zaytsev
2008-12-24 0:26 ` Derek M Jones
2008-12-24 2:39 ` Alexey Zaytsev
2008-12-24 21:59 ` David Given
2008-12-24 23:10 ` Christopher Li
2008-12-25 0:14 ` Derek M Jones [this message]
[not found] ` <4952C758.8070605@numba-tu.com>
2008-12-25 0:15 ` Christopher Li
2008-12-25 17:12 ` Alexey Zaytsev
2008-12-23 5:51 ` Christopher Li
2008-12-23 6:09 ` Alexey Zaytsev
2008-12-18 22:33 ` [PATCH 08/16] Add test for acquire/release Alexey Zaytsev
2008-12-18 22:33 ` [PATCH 09/16] Add __exact_context__ Alexey Zaytsev
2008-12-18 22:33 ` [PATCH 10/16] Allow context() attribute on variables Alexey Zaytsev
2008-12-18 22:34 ` [PATCH 11/16] Evaluate/expand context expressions Alexey Zaytsev
2008-12-18 22:34 ` [PATCH 12/16] Revert the conditional_context patch Alexey Zaytsev
2008-12-18 22:34 ` [PATCH 13/16] Ceck context expressions as expressions Alexey Zaytsev
2008-12-18 22:35 ` [PATCH 14/16] Test conditional result locking Alexey Zaytsev
2008-12-18 22:35 ` [PATCH 15/16] Show required context in instruction output Alexey Zaytsev
2008-12-18 22:35 ` [PATCH 16/16] Check inlines explicitly Alexey Zaytsev
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