From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 10286 invoked by alias); 16 May 2011 18:09:51 -0000 Received: (qmail 10277 invoked by uid 22791); 16 May 2011 18:09:51 -0000 X-SWARE-Spam-Status: No, hits=-6.9 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_HI,SPF_HELO_PASS,T_RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Mon, 16 May 2011 18:09:33 +0000 Received: from int-mx01.intmail.prod.int.phx2.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id p4GI9VLr030356 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Mon, 16 May 2011 14:09:31 -0400 Received: from ns3.rdu.redhat.com (ns3.rdu.redhat.com [10.11.255.199]) by int-mx01.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id p4GI9U3U005604; Mon, 16 May 2011 14:09:31 -0400 Received: from opsy.redhat.com (ovpn01.gateway.prod.ext.phx2.redhat.com [10.5.9.1]) by ns3.rdu.redhat.com (8.13.8/8.13.8) with ESMTP id p4GI9U2x012612; Mon, 16 May 2011 14:09:30 -0400 Received: by opsy.redhat.com (Postfix, from userid 500) id C58C5379188; Mon, 16 May 2011 12:09:29 -0600 (MDT) From: Tom Tromey To: "Ulrich Weigand" Cc: gdb-patches@sourceware.org, Jakub Jelinek Subject: Re: RFC: implement typed DWARF stack References: <201105161550.p4GFo5hk014748@d06av02.portsmouth.uk.ibm.com> Date: Mon, 16 May 2011 18:09:00 -0000 In-Reply-To: <201105161550.p4GFo5hk014748@d06av02.portsmouth.uk.ibm.com> (Ulrich Weigand's message of "Mon, 16 May 2011 17:50:05 +0200 (CEST)") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii 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: 2011-05/txt/msg00365.txt.bz2 CCing Jakub. Ulrich> So just to clarify: in the discussion a while back, you said: Sorry for any confusion. I hope this email will clear it up. During our discussion I was convinced that DW_OP_shr should generally use the sign of any explicit type to decide what to do (with a special case for implicit type). However, Jakub informed me that GCC relied on 'shr' always zero-filling, even for explicit types. So, I changed the code back. What is now in the tree implements the same semantics that GCC assumes. Ulrich> With this latest patch, it is now definitely *not* the case that Ulrich> DW_OP_shr and DW_OP_shra behave the same on new-style typed Ulrich> values. Instead, as I pointed out originally, DW_OP_shr now Ulrich> always performs an unsigned operation, while DW_OP_shra respects Ulrich> the value's type ... Ulrich> Is that really what was intended? At least the shr part is intended. I did not consider the shra case. Ulrich> Or should rather DW_OP_shra now also be changed (to always Ulrich> perform a signed operation as its name suggests)? In other words, mirror the shr special case for shra. This makes sense to me. Jakub, what do you think? Tom