From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 17494 invoked by alias); 9 Mar 2012 07:22:01 -0000 Received: (qmail 17483 invoked by uid 22791); 9 Mar 2012 07:21:59 -0000 X-SWARE-Spam-Status: No, hits=-6.6 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_HI,SPF_HELO_PASS,TW_XF,T_RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Fri, 09 Mar 2012 07:21:45 +0000 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id q297LUmN024422 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Fri, 9 Mar 2012 02:21:30 -0500 Received: from host2.jankratochvil.net (ovpn-116-19.ams2.redhat.com [10.36.116.19]) by int-mx10.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id q297LPXf014303 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NO); Fri, 9 Mar 2012 02:21:28 -0500 Date: Fri, 09 Mar 2012 07:22:00 -0000 From: Jan Kratochvil To: gdb-patches@sourceware.org Cc: Ulrich Weigand , Joel Brobecker Subject: cancel: [patch] Fix gdb.cp/gdb2495.exp regression with gcc-4.7 #4 [Re: [revert] Regression on PowerPC] Message-ID: <20120309072125.GA517@host2.jankratochvil.net> References: <20120103155206.GM2730@adacore.com> <201201031444.q03Eir77009359@d06av02.portsmouth.uk.ibm.com> <20120104140104.GA22254@host2.jankratochvil.net> <20120308232345.GA32618@host2.jankratochvil.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120308232345.GA32618@host2.jankratochvil.net> User-Agent: Mutt/1.5.21 (2010-09-15) X-IsSubscribed: yes 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: 2012-03/txt/msg00322.txt.bz2 On Fri, 09 Mar 2012 00:23:45 +0100, Jan Kratochvil wrote: > 2012-03-09 Jan Kratochvil > > * amd64-linux-tdep.c: Include inferior.h. > (amd64_linux_init_abi): Set ON_STACK and i386_linux_push_dummy_code. > * i386-linux-tdep.c (i386_linux_push_dummy_code): New function. > (i386_linux_init_abi): Set ON_STACK and i386_linux_push_dummy_code. > * i386-tdep.h (i386_linux_push_dummy_code): New declaration. FYI cancelling this patch, it has some issues: (1) As i386-tdep.c already has OS-independent i386_push_dummy_call I believe push_dummy_code can be also put into i386-tdep.c. (2) At least on RHEL-5 i386 there is a regression: FAIL: gdb.base/call-signal-resume.exp: continue to program exit #0 null_hand_call () at ./gdb.base/call-signals.c:56 #1 #2 0xf7fe0430 in __kernel_vsyscall () #3 0xf7e7d236 in kill () from /lib/libc.so.6 #4 0x080484f4 in gen_signal () at ./gdb.base/call-signals.c:35 #5 0x08048574 in main () at ./gdb.base/call-signals.c:81 -> #0 null_hand_call () at ./gdb.base/call-signals.c:56 #1 #2 0xf7fe0430 in __kernel_vsyscall () #3 0xf7e7d236 in kill () from /lib/libc.so.6 #4 0xf70484f4 in ?? () #5 0x00004b03 in ?? () #6 0x00000006 in ?? () #7 0xffffd068 in ?? () #8 0x08048574 in main () at ./gdb.base/call-signals.c:81 This is because (a) the dummy frame has no associated DWARF/EH frame unwind info and i386_push_dummy_call does not setup proper frame pointer in the new frame. Moreover I believe it should be setup with 0 frame pointer / 0 return address to indicate end of unwinding for possible inferior unwinders, IMO inferior should not unwind through the dummy frame. And then therefore GDB needs new frame_unwind to properly unwind that 0 return address / frame pointer. Regards, Jan