From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 77123 invoked by alias); 7 Feb 2017 14:16:06 -0000 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 Received: (qmail 75819 invoked by uid 89); 7 Feb 2017 14:16:05 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.1 required=5.0 tests=AWL,BAYES_00,FREEMAIL_FROM,RCVD_IN_DNSWL_LOW,RCVD_IN_SORBS_SPAM,SPF_PASS autolearn=ham version=3.3.2 spammy=handlers, Hx-languages-length:1287, H*MI:sk:CAGWvny, Hx-spam-relays-external:209.85.216.196 X-HELO: mail-qt0-f196.google.com Received: from mail-qt0-f196.google.com (HELO mail-qt0-f196.google.com) (209.85.216.196) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Tue, 07 Feb 2017 14:15:55 +0000 Received: by mail-qt0-f196.google.com with SMTP id n13so19272306qtc.0 for ; Tue, 07 Feb 2017 06:15:55 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=8dwc36G6TvR1h9KkgCVi/aaU3ykhxyWKqqBj67Cn9DY=; b=Pt5lkSwIWPKN9hoUQzrDWSvvkSZLC/S+RcSCcAhL6RM9Mb5gYZYjfYt+Zn8wHdPKWm i//CuXzUvHqgHeQzm4YkMh6F4j0w+YFWkmVbnuX3+TA8OkhQIgabThqSDWanbCuqEFC3 bMyk6bAFbgfCCogl6YoMxmqVb1XL1rWcvQGJjp6AChliT62hc7zVRMiLEateKMHxaa2e B7L9aXnis9frsZ54EZfLD0LTRyhZ8snIzQjMm14TDXu7UaefTr5pPPZnkp5IuaxhGzxV w+vdu2VrOFWalrTTN32bwl72kPknWBxibu1PpK5y1VZtYksQcGelMyVmHKfqCO+mnEnD UIIg== X-Gm-Message-State: AMke39nV+w9QeItMpUlg3IS4mlegEdyMhG802hj7K8at3tE/8/zvROI5clzpT+HihIdFXlNgA3BiCbnaoGqm3A== X-Received: by 10.200.34.155 with SMTP id f27mr13709167qta.129.1486476954301; Tue, 07 Feb 2017 06:15:54 -0800 (PST) MIME-Version: 1.0 Received: by 10.12.181.202 with HTTP; Tue, 7 Feb 2017 06:15:53 -0800 (PST) In-Reply-To: <57147db4-83c3-2a8f-0c74-0efc6a94e9f5@redhat.com> References: <21a21388-b1d9-816c-377e-d4e084cc399e@redhat.com> <331a72d9-050c-7cd7-adc2-78e5f1ed6f85@redhat.com> <57147db4-83c3-2a8f-0c74-0efc6a94e9f5@redhat.com> From: David Edelsohn Date: Tue, 07 Feb 2017 14:16:00 -0000 Message-ID: Subject: Re: Issue with Latest GDB on AIX with GCC-6.12 To: Pedro Alves Cc: Nitish Kumar Mishra , "gdb@sourceware.org" , Yao Qi Content-Type: text/plain; charset=UTF-8 X-SW-Source: 2017-02/txt/msg00005.txt.bz2 On Tue, Feb 7, 2017 at 8:56 AM, Pedro Alves wrote: > On 02/07/2017 01:44 PM, David Edelsohn wrote: >> On Tue, Feb 7, 2017 at 5:30 AM, Pedro Alves wrote: >> >>> Speaking of compilers, we know that building gdb with gcc 4.8.5 >>> doesn't run into this. Do we know that changed? Did, for example, >>> AIX switch from sjlj to dwarf-based exceptions between gcc 4.8.5 >>> and 6.1? Might also be useful to try to build gdb with current >>> gcc trunk / gcc 7. >> >> I cannot tell if some have reported that GCC 4.8.5 works correctly or not. > > The OP said it works fine on GCC 4.8.5 here: > > https://sourceware.org/ml/gdb/2017-01/msg00044.html Yes, but I thought that there was a later comment that GCC 4.8 also showed problems. There was a change in the encoding of data for AIX, but not a change to the basic EH frames or handlers. AIX did not change EH mechanisms and never used SJLJ -- at least not for a very long time. One test is to use shared libraries to link GDB. Another possible contribution is the AIX address space. There have been reports in the past of EH frames not sorted correctly and libgcc EH not finding exception handlers because it terminated the search early. Thanks, David