From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 15053 invoked by alias); 10 May 2007 01:21:27 -0000 Received: (qmail 15023 invoked by uid 22791); 10 May 2007 01:21:27 -0000 X-Spam-Check-By: sourceware.org Received: from pop-knobcone.atl.sa.earthlink.net (HELO pop-knobcone.atl.sa.earthlink.net) (207.69.195.64) by sourceware.org (qpsmtpd/0.31) with ESMTP; Thu, 10 May 2007 01:21:24 +0000 Received: from cpe-66-1-132-251.ca.sprintbbd.net ([66.1.132.251] helo=[192.168.1.2]) by pop-knobcone.atl.sa.earthlink.net with esmtp (Exim 3.36 #1) id 1HlxLO-0000hK-00 for gdb@sourceware.org; Wed, 09 May 2007 21:21:22 -0400 Message-ID: <4642729E.7010406@earthlink.net> Date: Thu, 10 May 2007 01:21:00 -0000 From: David Anderson User-Agent: Thunderbird 1.5.0.10 (X11/20070221) MIME-Version: 1.0 To: gdb@sourceware.org Subject: Re: DWARF-2 expression error in location list entries Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Mailing-List: contact gdb-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-owner@sourceware.org X-SW-Source: 2007-05/txt/msg00041.txt.bz2 > A couple of us have looked for that first restriction in the DWARF3 > standard and not found it. I also went back to the DWARF2 standard > literally cited by the message and failed to find it there as well. Can > anyone point out where to read the restriction these error() calls refer to? The clearest hint is in DWARF3 2.6.1: "The following DWARF operations can be used to name a register. They can be used only in location expressions. Each register name operator must be used alone (as a DWARF expression consisting of just that one operation)." (goes on to mention DW_OP_reg*). It's true that this is not as clear as it should be (DW_OP_piece is not mentioned in 2.6.1, for example). 2.6.2 does try to clarify this, but it's not easy to interpret. But Daniel Jacobowitz is exactly right. These can only be used stand-alone (or with DW_OP_piece). Jim Blandy suggested a nice little grammar which made all this quite clear (March 8 2007, dwarf-discuss mailing list). The lack of clarity issue got lost in a discussion about a proposal on constant expressions in location lists. I'll resurrect Jim's suggestion for the DWARF committee. Regards, David Anderson