linux-kernel - Re: [PATCH 2.6.17-rc6 7/9] Remove some of the kmemleak false positives

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Date:	Mon, 24 Jul 2006 14:28:03 +0100
From:	"Catalin Marinas" <catalin.marinas@...il.com>
To:	"Ingo Molnar" <mingo@...e.hu>
Cc:	"Pekka Enberg" <penberg@...helsinki.fi>,
	linux-kernel@...r.kernel.org,
	"Arjan van de Ven" <arjan@...radead.org>
Subject: Re: [PATCH 2.6.17-rc6 7/9] Remove some of the kmemleak false positives

On 24/07/06, Ingo Molnar <mingo@...e.hu> wrote:
> update: there's also a neat gcc extension trick suggested by Arjan:
> __builtin_classify_type(). This converts types into integers!

It's not really reliable as it doesn't distinguish well between types.
All the structures, no matter what they contain, have the same id
(which I think only refers to the fact that it is built-in type,
pointer or structure, without differentiation).

The attached code gives the following results:

typeof(a) = 12, sizeof(a) = 136
typeof(b) = 12, sizeof(b) = 8
typeof(c) = 1, sizeof(c) = 4
typeof(d) = 1, sizeof(d) = 4
typeof(e) = 1, sizeof(e) = 4
typeof(f) = 1, sizeof(f) = 1
typeof(g) = 5, sizeof(g) = 4
typeof(h) = 5, sizeof(h) = 4

-- 
Catalin

View attachment "builtin_classify_type.c" of type "text/x-csrc" (506 bytes)