From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 30374 invoked by alias); 23 Dec 2010 04:22:58 -0000 Received: (qmail 30363 invoked by uid 22791); 23 Dec 2010 04:22:56 -0000 X-SWARE-Spam-Status: No, hits=-2.1 required=5.0 tests=AWL,BAYES_00 X-Spam-Check-By: sourceware.org Received: from rock.gnat.com (HELO rock.gnat.com) (205.232.38.15) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Thu, 23 Dec 2010 04:22:50 +0000 Received: from localhost (localhost.localdomain [127.0.0.1]) by filtered-rock.gnat.com (Postfix) with ESMTP id B184E2BACC1; Wed, 22 Dec 2010 23:22:48 -0500 (EST) Received: from rock.gnat.com ([127.0.0.1]) by localhost (rock.gnat.com [127.0.0.1]) (amavisd-new, port 10024) with LMTP id 9OeGKSSpNXqC; Wed, 22 Dec 2010 23:22:48 -0500 (EST) Received: from joel.gnat.com (localhost.localdomain [127.0.0.1]) by rock.gnat.com (Postfix) with ESMTP id 438432BACBF; Wed, 22 Dec 2010 23:22:48 -0500 (EST) Received: by joel.gnat.com (Postfix, from userid 1000) id 915861457B3; Thu, 23 Dec 2010 05:22:36 +0100 (CET) Date: Thu, 23 Dec 2010 04:54:00 -0000 From: Joel Brobecker To: Yao Qi Cc: gdb-patches@sourceware.org Subject: Re: [rfa] Update PC without side effect in displaced stepping Message-ID: <20101223042236.GS2596@adacore.com> References: <4D0F0ABA.9010506@codesourcery.com> <201012200804.oBK84oPu005379@glazunov.sibelius.xs4all.nl> <4D0F5D36.2040909@codesourcery.com> <4D10D377.8080100@codesourcery.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4D10D377.8080100@codesourcery.com> User-Agent: Mutt/1.5.20 (2009-06-14) Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org X-SW-Source: 2010-12/txt/msg00425.txt.bz2 > When writing the new patch, I re-consider this problem again. GDB > doesn't support displaced stepping on sparc and hppa, so it is not > harmful to sparc and hppa when regcache_write_pc is replaced by > regcache_cooked_write_unsigned. > Currently, GDB supports displaced stepping on s390, rs6000 (including > ppc-linux, aix), i386, amd64 and arm. AFAICS, this replacement in my > original patch is not harmful to these targets. [...] > Given my original patch is clean, and not harmful to existing targets > support displaced stepping, please consider my original patch again. > Comments on promising directions/approaches are welcome. I haven't seen the patch, so I cannot comment specifically, but I think that you are using the wrong reasons to try to justify your initial patch. It does not matter whether sparc or hppa support displaced stepping or not. They might - it's not far-fetched for sparc, for instance. Or other platforms where it matters might be contributed in the future, and they could need displaced stepping too. By letting your patch in, we would be making it harder for other platforms to implement it. It would feel like sweeping the dust under the carpet... -- Joel