From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 9543 invoked by alias); 10 Oct 2016 22:41:14 -0000 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 Received: (qmail 9534 invoked by uid 89); 10 Oct 2016 22:41:14 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.8 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_NONE,SPF_PASS autolearn=ham version=3.3.2 spammy=usefulness X-HELO: gproxy8-pub.mail.unifiedlayer.com Received: from gproxy8-pub.mail.unifiedlayer.com (HELO gproxy8-pub.mail.unifiedlayer.com) (67.222.33.93) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with SMTP; Mon, 10 Oct 2016 22:41:04 +0000 Received: (qmail 3686 invoked by uid 0); 10 Oct 2016 22:41:02 -0000 Received: from unknown (HELO cmgw4) (10.0.90.85) by gproxy8.mail.unifiedlayer.com with SMTP; 10 Oct 2016 22:41:02 -0000 Received: from box522.bluehost.com ([74.220.219.122]) by cmgw4 with id tygz1t0092f2jeq01yh2lk; Mon, 10 Oct 2016 16:41:02 -0600 X-Authority-Analysis: v=2.1 cv=IecUBwaa c=1 sm=1 tr=0 a=GsOEXm/OWkKvwdLVJsfwcA==:117 a=GsOEXm/OWkKvwdLVJsfwcA==:17 a=L9H7d07YOLsA:10 a=9cW_t1CCXrUA:10 a=s5jvgZ67dGcA:10 a=CH0kA5CcgfcA:10 a=VnNF1IyMAAAA:8 a=umocyWIRRw-zR6SQJCcA:9 a=skCgnbhlp52w9zbo2JeP:22 Received: from 71-218-192-86.hlrn.qwest.net ([71.218.192.86]:50684 helo=bapiya) by box522.bluehost.com with esmtpsa (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.86_1) (envelope-from ) id 1btjFi-0006ur-TJ; Mon, 10 Oct 2016 16:40:59 -0600 From: Tom Tromey To: Andreas Arnez Cc: Tom Tromey , gdb-patches@sourceware.org Subject: Re: [PATCH] Allow DW_OP_GNU_uninit in dwarf_expr_require_composition References: <87lgxxctli.fsf@tromey.com> Date: Mon, 10 Oct 2016 22:41:00 -0000 In-Reply-To: (Andreas Arnez's message of "Mon, 10 Oct 2016 14:24:23 +0200") Message-ID: <874m4jq13d.fsf@tromey.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.1.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-BWhitelist: no X-Exim-ID: 1btjFi-0006ur-TJ X-Source-Sender: 71-218-192-86.hlrn.qwest.net (bapiya) [71.218.192.86]:50684 X-Source-Auth: tom+tromey.com X-Email-Count: 4 X-Source-Cap: ZWx5bnJvYmk7ZWx5bnJvYmk7Ym94NTIyLmJsdWVob3N0LmNvbQ== X-SW-Source: 2016-10/txt/msg00234.txt.bz2 >>>>> "Andreas" == Andreas Arnez writes: Andreas> You mean to allow DW_OP_GNU_uninit to terminate any simple Andreas> location description? Yes. >> That is, assuming DW_OP_GNU_uninit is useful at all. >> Another option would be to deprecate it. Andreas> Right, I wonder about its usefulness as well. For a variable Andreas> with fixed location it may cover a small window where the Andreas> compiler can be certain that the variable is uninitialized. I Andreas> guess this *might* be useful sometimes? Andreas> Is there even a DWARF issue for this? Or a formal Andreas> specification? I don't think so. Last time I looked into this all I was able to find were the patch submissions to gcc and gdb. IIRC they weren't all that informative though. Tom