From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 17684 invoked by alias); 3 Jan 2012 14:45:35 -0000 Received: (qmail 17654 invoked by uid 22791); 3 Jan 2012 14:45:31 -0000 X-SWARE-Spam-Status: No, hits=-2.6 required=5.0 tests=AWL,BAYES_00,MSGID_FROM_MTA_HEADER,RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Received: from e06smtp17.uk.ibm.com (HELO e06smtp17.uk.ibm.com) (195.75.94.113) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Tue, 03 Jan 2012 14:45:16 +0000 Received: from /spool/local by e06smtp17.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 3 Jan 2012 14:45:15 -0000 Received: from d06nrmr1507.portsmouth.uk.ibm.com ([9.149.38.233]) by e06smtp17.uk.ibm.com ([192.168.101.147]) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; Tue, 3 Jan 2012 14:44:55 -0000 Received: from d06av02.portsmouth.uk.ibm.com (d06av02.portsmouth.uk.ibm.com [9.149.37.228]) by d06nrmr1507.portsmouth.uk.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id q03EittV2052174 for ; Tue, 3 Jan 2012 14:44:55 GMT Received: from d06av02.portsmouth.uk.ibm.com (loopback [127.0.0.1]) by d06av02.portsmouth.uk.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id q03EisDj009414 for ; Tue, 3 Jan 2012 07:44:55 -0700 Received: from tuxmaker.boeblingen.de.ibm.com (tuxmaker.boeblingen.de.ibm.com [9.152.85.9]) by d06av02.portsmouth.uk.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with SMTP id q03Eir77009359; Tue, 3 Jan 2012 07:44:53 -0700 Message-Id: <201201031444.q03Eir77009359@d06av02.portsmouth.uk.ibm.com> Received: by tuxmaker.boeblingen.de.ibm.com (sSMTP sendmail emulation); Tue, 03 Jan 2012 15:44:53 +0100 Subject: Regression on PowerPC (Re: [patch] Fix gdb.cp/gdb2495.exp regression with gcc-4.7 #3) To: jan.kratochvil@redhat.com (Jan Kratochvil) Date: Tue, 03 Jan 2012 14:45:00 -0000 From: "Ulrich Weigand" Cc: brobecker@adacore.com (Joel Brobecker), gdb-patches@sourceware.org In-Reply-To: <20120102025758.GA20654@host2.jankratochvil.net> from "Jan Kratochvil" at Jan 02, 2012 03:57:58 AM MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit x-cbid: 12010314-0542-0000-0000-0000008F7EBD 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: 2012-01/txt/msg00093.txt.bz2 Jan Kratochvil wrote: > On Mon, 02 Jan 2012 03:45:32 +0100, Joel Brobecker wrote: > > and maybe this one. For yours, there's been enough > > scrutiny I think that it can go in I think that it can go in already. > > Checked in: > http://sourceware.org/ml/gdb-cvs/2012-01/msg00013.html > Checked in 7.4: > http://sourceware.org/ml/gdb-cvs/2012-01/msg00014.html This seems to have caused FAIL: gdb.cp/gdb2495.exp: Call a function that raises an exception without a handler. (timeout) FAIL: gdb.cp/gdb2495.exp: bt after returning from a popped frame (timeout) FAIL: gdb.cp/gdb2495.exp: info breakpoints (timeout) FAIL: gdb.cp/gdb2495.exp: (timeout) set unwind-on-terminating-exception off FAIL: gdb.cp/gdb2495.exp: Turn off unwind on terminating exception flag (timeout) FAIL: gdb.cp/gdb2495.exp: Call a function that raises an exception with unwinding off.. (timeout) ERROR: Delete all breakpoints in delete_breakpoints (timeout) UNRESOLVED: gdb.cp/gdb2495.exp: setting breakpoint at main (timeout) on powerpc-linux and powerpc64-linux. I think the problem is that your statement as of here: "_start at least on GNU/Linux does not have .eh_frame FDE for itself." (http://sourceware.org/ml/gdb-patches/2011-12/msg00873.html) is actually not true on PowerPC (at least on my RHEL5 system): [uweigand@cellntc3 ~]$ readelf -wf /usr/lib64/crt1.o The section .eh_frame contains: 00000000 00000010 00000000 CIE Version: 1 Augmentation: "zR" Code alignment factor: 4 Data alignment factor: -8 Return address column: 65 Augmentation data: 1b DW_CFA_def_cfa: r1 ofs 0 00000014 00000010 00000018 FDE cie=00000000 pc=00000000..00000024 DW_CFA_nop DW_CFA_nop DW_CFA_nop When the unwinder runs into this FDE and assumes it is valid for the dummy frame, it goes into an endless loop ... Switching to the ON_STACK method fixes this for me. But I'm not sure if there are other platforms beside PowerPC that have the same problem ... Maybe we ought to default to ON_STACK (at least on Linux?)? Note that it's a bit annoying that we need to provide a push_dummy_code routine in order to be able to use ON_STACK. Maybe there should be a default implementation based on gdbarch_inner_than/gdbarch_frame_align_p and the breakpoint length? Bye, Ulrich -- Dr. Ulrich Weigand GNU Toolchain for Linux on System z and Cell BE Ulrich.Weigand@de.ibm.com