From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1422824AbWHYEDd (ORCPT ); Fri, 25 Aug 2006 00:03:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1422826AbWHYEDd (ORCPT ); Fri, 25 Aug 2006 00:03:33 -0400 Received: from ozlabs.org ([203.10.76.45]:49799 "EHLO ozlabs.org") by vger.kernel.org with ESMTP id S1422824AbWHYEDc (ORCPT ); Fri, 25 Aug 2006 00:03:32 -0400 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <17646.29510.296315.569294@cargo.ozlabs.ibm.com> Date: Fri, 25 Aug 2006 13:49:26 +1000 From: Paul Mackerras To: "Dong Feng" Cc: ak@suse.de, "Christoph Lameter" , linux-kernel@vger.kernel.org Subject: Re: Unnecessary Relocation Hiding? In-Reply-To: References: <17646.14056.102017.127644@cargo.ozlabs.ibm.com> X-Mailer: VM 7.19 under Emacs 21.4.1 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Dong Feng writes: > Sorry for perhaps extending the specific question to a more generic > one. In which cases shall we, in current or future development, > prevent gcc from knowing a pointer-addition in the way RELOC_HIDE? And > in what cases shall we just write pure C point addition? Where you are saying to gcc "you think this variable is at this address, but I know it's actually at this other address over here" you should use RELOC_HIDE. Where the addition is being used to get the address of some part of the object (so the resulting address is still within the object) you can just use plain addition. Paul.