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Date: Sun, 7 Jun 2009 00:12:23 +0200
From: Sam Ravnborg <sam@ravnborg.org>
To: Russell King <rmk+lkml@arm.linux.org.uk>
Cc: Jaswinder Singh Rajput <jaswinder@kernel.org>,
       Linus Torvalds <torvalds@linux-foundation.org>,
       Ingo Molnar <mingo@elte.hu>, Catalin Marinas <catalin.marinas@arm.com>,
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       Greg Ungerer <gerg@snapgear.com>, Ralf Baechle <ralf@linux-mips.org>,
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       Andrew Morton <akpm@linux-foundation.org>,
       LKML <linux-kernel@vger.kernel.org>,
       David Howells <dhowells@redhat.com>
Subject: Re: [GIT PULL] headers_check fixes
Message-ID: <20090606221223.GA20945@uranus.ravnborg.org>
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Hi Russell.

On Sat, Jun 06, 2009 at 10:47:11PM +0100, Russell King wrote:
> Right, below is a patch to unifdef.c which allows it to work out if
> an #if expression always evaluates true or false for symbols which
> are being undefined/always defined.
> 
> The patch is slightly more complicated than I'd hoped because unifdef
> needs to see lines fully evaluated - doing otherwise causes it to
> mark the line as "dirty" and copy it over no matter what.
> 
> What follows this email is the diff of what effect it has on the
> headers copied over - as can be seen, all resulting changes are of
> net benefit.

You beat me on this one.
I was looking into supportting short_circuit_and/short_circuit_or too.
Your patch looks better - thanks!

>>From my very limited testing this patch suffers from a problem I faced too.
When you run it on for example hwcap.h or my sample file:
#if defined(__KERNEL__) && !defined(__ASSEMBLY__)
  int a;
#endif

then the return code of the program is 1 so we do not copy the file.

I'm heading for bed - will take a closer look tomorrow.

	Sam