linux-kernel - Re: Definition of BUG on x86

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Date:	Thu, 19 Feb 2009 10:38:31 -0800
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Petr Tesarik <ptesarik@...e.cz>
CC:	Jeremy Fitzhardinge <jeremy@...p.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: Definition of BUG on x86

Petr Tesarik wrote:
> 
> Ah, yes, you're right. If you want to make gcc aware of the fact that a
> function never returns, it must recognize that there is no path to that
> function's EXIT, otherwise it will emit a warning (which is pretty
> annoying, indeed). Since we don't want to make a call/jmp to an external
> noreturn function, so the no-return code must be directly visible to
> gcc. Unfortunately, there is no way of telling gcc that an asm statement
> does not return.
> 

At Transmeta, we had an internal hack to gcc that added
__builtin_not_reached(); for this particular reason.  This would
probably be the best way to handle this.

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.

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