From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 10955 invoked by alias); 20 Aug 2013 15:19:27 -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 10946 invoked by uid 89); 20 Aug 2013 15:19:26 -0000 X-Spam-SWARE-Status: No, score=-4.7 required=5.0 tests=AWL,BAYES_00,KHOP_RCVD_UNTRUST,KHOP_THREADED,RCVD_IN_HOSTKARMA_W,RCVD_IN_HOSTKARMA_WL autolearn=ham version=3.3.2 Received: from relay1.mentorg.com (HELO relay1.mentorg.com) (192.94.38.131) by sourceware.org (qpsmtpd/0.84/v0.84-167-ge50287c) with ESMTP; Tue, 20 Aug 2013 15:19:25 +0000 Received: from svr-orw-exc-10.mgc.mentorg.com ([147.34.98.58]) by relay1.mentorg.com with esmtp id 1VBniN-0001yC-36 from joseph_myers@mentor.com ; Tue, 20 Aug 2013 08:19:23 -0700 Received: from SVR-IES-FEM-01.mgc.mentorg.com ([137.202.0.104]) by SVR-ORW-EXC-10.mgc.mentorg.com with Microsoft SMTPSVC(6.0.3790.4675); Tue, 20 Aug 2013 08:19:22 -0700 Received: from digraph.polyomino.org.uk (137.202.0.76) by SVR-IES-FEM-01.mgc.mentorg.com (137.202.0.104) with Microsoft SMTP Server id 14.2.247.3; Tue, 20 Aug 2013 16:19:21 +0100 Received: from jsm28 (helo=localhost) by digraph.polyomino.org.uk with local-esmtp (Exim 4.76) (envelope-from ) id 1VBniK-0007fc-DT; Tue, 20 Aug 2013 15:19:20 +0000 Date: Tue, 20 Aug 2013 15:19:00 -0000 From: "Joseph S. Myers" To: "Maciej W. Rozycki" CC: Tom Tromey , Subject: Re: [PATCH] remove ECOFF In-Reply-To: Message-ID: References: <1376936369-30712-1-git-send-email-tromey@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" X-SW-Source: 2013-08/txt/msg00541.txt.bz2 On Mon, 19 Aug 2013, Maciej W. Rozycki wrote: > We have kept maintaining bare-iron MIPS PDR support in CodeBench and my > intent is to enable it for Linux MIPS targets, add the heuristic outlined > above and resurrect the old code GDB used to have with the improvements > included. Without that debugging is often a challenge -- while the > heuristic unwinders are good enough to handle stepping in to a function > that has no debug information so that it's skipped over with the usual > `step' or `next' CLI operations (and their MI equivalents), interrupting a > program randomly within a function that has no debug information -- a > common scenario e.g. where a Linux process is sleeping in a syscall > invoked from stripped libc -- provides the user with no backtrace and > therefore no access to any local state or the ability to control execution > other than by instruction-level stepping (`stepi' or `nexti'). Rather than resurrecting this legacy MIPS-specific support, it would seem a lot better on Linux to generate .eh_frame by default (as on various other architectures) and phase out any remaining PDR generation there. For glibc 2.18 the eh_frame CFI information is present in many assembly sources and it could be added to the rest. -- Joseph S. Myers joseph@codesourcery.com