From: Rusty Russell <rusty@rustcorp.com.au>
To: Alexey Dobriyan <adobriyan@gmail.com>
Cc: torvalds@osdl.org, akpm@osdl.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] BUILD_BUG_ON sucks
Date: Sat, 16 Aug 2008 20:55:44 +1000 [thread overview]
Message-ID: <200808162055.45136.rusty@rustcorp.com.au> (raw)
In-Reply-To: <20080816100948.GB19926@martell.zuzino.mipt.ru>
On Saturday 16 August 2008 20:09:48 Alexey Dobriyan wrote:
> BUILD_BUG_ON should have never existed -- BUG_ON could upgrade itself to
> compile-breaking version if compiler has enough information and this is
> what patch does.
>
> The only downside is that one can't write BUG_ON(1) anymore.
Interesting idea, but I've come to actually like the semantic explicitness of
BUILD_BUG_ON. There's a difference between "we should never get here"
and "this should never exist".
But maybe I just like it because we have it. At very least BUILD_BUG_ON
should definitely compile-barf on a non-constant expr, and vice versa for
BUG_ON().
Note that BUG_ON() is a hack caused by lack of attribute((cold)). "if (x)
BUG()" is clearer, and possible in the long run as people upgrade compilers.
Cheers,
Rusty.
next prev parent reply other threads:[~2008-08-16 10:56 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-08-16 10:09 [PATCH] BUILD_BUG_ON sucks Alexey Dobriyan
2008-08-16 10:55 ` Rusty Russell [this message]
2008-08-16 20:07 ` Linus Torvalds
2008-08-17 10:32 ` [PATCH] debug: fix BUILD_BUG_ON() for non-constant expressions Ingo Molnar
2008-08-17 16:56 ` Linus Torvalds
2008-08-17 17:33 ` Ingo Molnar
2008-08-17 17:53 ` Ingo Molnar
2008-08-17 18:39 ` Linus Torvalds
2008-08-17 18:45 ` Ingo Molnar
2008-08-18 1:09 ` Rusty Russell
2008-08-18 7:54 ` Ingo Molnar
2008-08-18 9:55 ` Boaz Harrosh
2008-08-18 12:32 ` Boaz Harrosh
2008-08-19 13:34 ` Ingo Molnar
2008-08-19 16:33 ` Boaz Harrosh
2008-08-20 10:59 ` Ingo Molnar
2008-08-20 12:31 ` Boaz Harrosh
2008-08-20 12:39 ` adobriyan
2008-08-20 13:07 ` Boaz Harrosh
2008-08-21 12:17 ` Ingo Molnar
2008-08-25 1:19 ` Rusty Russell
2008-08-20 13:21 ` Boaz Harrosh
2008-08-16 17:46 ` [PATCH] BUILD_BUG_ON sucks Andrew Morton
2008-08-17 12:19 ` Theodore Tso
2008-08-17 16:33 ` Andrew Morton
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