From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 4231 invoked by alias); 24 Nov 2005 10:21:07 -0000 Received: (qmail 4219 invoked by uid 22791); 24 Nov 2005 10:21:06 -0000 X-Spam-Check-By: sourceware.org Received: from mtagate2.de.ibm.com (HELO mtagate2.de.ibm.com) (195.212.29.151) by sourceware.org (qpsmtpd/0.31) with ESMTP; Thu, 24 Nov 2005 10:21:04 +0000 Received: from d12nrmr1607.megacenter.de.ibm.com (d12nrmr1607.megacenter.de.ibm.com [9.149.167.49]) by mtagate2.de.ibm.com (8.12.10/8.12.10) with ESMTP id jAOAL5sj220426 for ; Thu, 24 Nov 2005 10:21:05 GMT Received: from d12av02.megacenter.de.ibm.com (d12av02.megacenter.de.ibm.com [9.149.165.228]) by d12nrmr1607.megacenter.de.ibm.com (8.12.10/NCO/VERS6.8) with ESMTP id jAOAL05W224092 for ; Thu, 24 Nov 2005 11:21:00 +0100 Received: from d12av02.megacenter.de.ibm.com (loopback [127.0.0.1]) by d12av02.megacenter.de.ibm.com (8.12.11/8.13.3) with ESMTP id jAOAL0gU029843 for ; Thu, 24 Nov 2005 11:21:00 +0100 Received: from 53v30g15.boeblingen.de.ibm.com (53v30g15.boeblingen.de.ibm.com [9.152.26.155]) by d12av02.megacenter.de.ibm.com (8.12.11/8.12.11) with ESMTP id jAOAL0j8029830; Thu, 24 Nov 2005 11:21:00 +0100 Received: from 53v30g15.boeblingen.de.ibm.com (localhost [127.0.0.1]) by 53v30g15.boeblingen.de.ibm.com (8.12.10/8.12.10) with ESMTP id jAOAKZU9015799; Thu, 24 Nov 2005 11:20:35 +0100 Received: (from uweigand@localhost) by 53v30g15.boeblingen.de.ibm.com (8.12.10/8.12.10/Submit) id jAOAKUpQ015796; Thu, 24 Nov 2005 11:20:30 +0100 From: Ulrich Weigand Message-Id: <200511241020.jAOAKUpQ015796@53v30g15.boeblingen.de.ibm.com> Subject: Re: Prologue analysis interface To: jimb@red-bean.com (Jim Blandy) Date: Thu, 24 Nov 2005 17:18:00 -0000 Cc: uweigand@de.ibm.com (Ulrich Weigand), brobecker@adacore.com (Joel Brobecker), gdb@sourceware.org In-Reply-To: <8f2776cb0511232221v6b54dee4i22d7dbb1f587b4bf@mail.gmail.com> from "Jim Blandy" at Nov 23, 2005 10:21:53 PM MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Mailing-List: contact gdb-help@sourceware.org; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-owner@sourceware.org X-SW-Source: 2005-11/txt/msg00542.txt.bz2 Jim Blandy wrote: > On 11/23/05, Ulrich Weigand wrote: > > Just one comment on this: the CFA is not necessarily the original SP > > (on s390 we have a constant offset). We'd have to leave it to platform > > code to actually determine the CFA itself. > > Why does your CFA need to be an offset from the original SP? Aside > from some more code needing to add an offset itself, what would break? Well, as CFA is just convention, it does *need* an offset as such. However, fact is that this is how CFA is currently registered in DWARF-2 CFI generated by GCC (due to an historical accident ...). Changing this is difficult: if you were to mix object files built with different CFA base locations, ordering of CFA values along the stack frame chain would no longer be guaranteed. (The same would hold if GDB internally used different CFA conventions for DWARF-2 detected frames and prolog-parser detected frames ...) Bye, Ulrich -- Dr. Ulrich Weigand Linux on zSeries Development Ulrich.Weigand@de.ibm.com