From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 11518 invoked by alias); 11 Jun 2009 15:47:22 -0000 Received: (qmail 11510 invoked by uid 22791); 11 Jun 2009 15:47:22 -0000 X-SWARE-Spam-Status: No, hits=-2.3 required=5.0 tests=AWL,BAYES_00,SPF_HELO_PASS,SPF_PASS X-Spam-Check-By: sourceware.org Received: from mx2.redhat.com (HELO mx2.redhat.com) (66.187.237.31) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Thu, 11 Jun 2009 15:47:16 +0000 Received: from int-mx2.corp.redhat.com (int-mx2.corp.redhat.com [172.16.27.26]) by mx2.redhat.com (8.13.8/8.13.8) with ESMTP id n5BFipch022558; Thu, 11 Jun 2009 11:44:51 -0400 Received: from ns3.rdu.redhat.com (ns3.rdu.redhat.com [10.11.255.199]) by int-mx2.corp.redhat.com (8.13.1/8.13.1) with ESMTP id n5BFio5R026613; Thu, 11 Jun 2009 11:44:50 -0400 Received: from opsy.redhat.com (vpn-12-124.rdu.redhat.com [10.11.12.124]) by ns3.rdu.redhat.com (8.13.8/8.13.8) with ESMTP id n5BFing5008875; Thu, 11 Jun 2009 11:44:50 -0400 Received: by opsy.redhat.com (Postfix, from userid 500) id BA38037818B; Thu, 11 Jun 2009 09:44:48 -0600 (MDT) To: Joel Brobecker Cc: gdb-patches@sourceware.org Subject: Re: RFC: next/finish/etc -vs- exceptions References: <20090610161204.GB25703@adacore.com> <20090611144513.GE25703@adacore.com> From: Tom Tromey Reply-To: tromey@redhat.com Date: Thu, 11 Jun 2009 15:47:00 -0000 In-Reply-To: <20090611144513.GE25703@adacore.com> (Joel Brobecker's message of "Thu\, 11 Jun 2009 10\:45\:13 -0400") Message-ID: User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.2 (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: 2009-06/txt/msg00305.txt.bz2 >>>>> "Joel" == Joel Brobecker writes: Joel> Actually, we have two possible mechanisms, but I think we prefer the Joel> "Zero Cost Exception" mechanism, which doesn't use setjmp/longjmp Joel> because having an exception handler then costs nothing. We assume Joel> that exceptions are rare occurences, and therefore don't wan't to Joel> spent time setting up a handler if we're not going to use it. Ok, great. If Ada uses the same unwinder code as the rest of gcc -- in particular, unwind-dw2.c -- then this patch will "just work" for Ada as it does for Java and C++. That is because the debug hook in the unwinder is inserted at the very lowest level. Note that I have not updated all the unwinders. In particular this will not work on IA-64, on any platform using unwind-sjlj.c (but those should be covered by the ordinary longjmp code), or I think on Xtensa or ARM (based on the existence of unwind-$arch.c in the gcc tree). Tom