From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 7359 invoked by alias); 19 Nov 2014 09:48:53 -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 7340 invoked by uid 89); 19 Nov 2014 09:48:51 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.0 required=5.0 tests=AWL,BAYES_00,SPF_HELO_PASS,SPF_PASS,T_RP_MATCHES_RCVD autolearn=ham version=3.3.2 X-HELO: mx1.redhat.com Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-GCM-SHA384 encrypted) ESMTPS; Wed, 19 Nov 2014 09:48:49 +0000 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id sAJ9mCij016799 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Wed, 19 Nov 2014 04:48:13 -0500 Received: from [127.0.0.1] (ovpn01.gateway.prod.ext.ams2.redhat.com [10.39.146.11]) by int-mx13.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id sAJ9mACv032732; Wed, 19 Nov 2014 04:48:11 -0500 Message-ID: <546C675A.2080207@redhat.com> Date: Wed, 19 Nov 2014 09:48:00 -0000 From: Pedro Alves User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.1.1 MIME-Version: 1.0 To: Yao Qi , Nan Xiao CC: gdb Subject: Re: How to use "frame addr" command in gdb? References: <874mtvhegh.fsf@codesourcery.com> In-Reply-To: <874mtvhegh.fsf@codesourcery.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-SW-Source: 2014-11/txt/msg00028.txt.bz2 BTW, I think I've argued before that "frame NUMBER" shouldn't fallback to creating a frame chain starting at NUMBER if no frame number NUMBER, nor a frame at adderss NUMBER is found in the frame chain. If I haven't, I'll do that now. :-) That's highly misleading, because the user is more likely to be trying to select a frame by number, like: (top-gdb) bt #0 gdb_main (args=0x7fffffffd810) at src/gdb/main.c:1157 #1 0x00000000004638e7 in main (argc=1, argv=0x7fffffffd918) at src/gdb/gdb.c:32 (top-gdb) frame 0 #0 gdb_main (args=0x7fffffffd810) at src/gdb/main.c:1157 1157 catch_errors (captured_main, args, "", RETURN_MASK_ALL); (top-gdb) frame 1 #1 0x00000000004638e7 in main (argc=1, argv=0x7fffffffd918) at src/gdb/gdb.c:32 32 return gdb_main (&args); (top-gdb) frame 2 #0 0x0000000000000000 in ?? () (top-gdb) For the "frame 2" above, I'd much rather that gdb complained with "no frame number 2". For the OP's case, I'd rather that gdb complained with "no frame at ADDR". For the use case of actually telling GDB to inspect a frame at some address not on the unwound frame chain, the user would need to ask that from GDB explicitly. That would mean we'd have something like: (gdb) frame number NUM (gdb) frame NUM (alias for "frame number") (gdb) frame address ADDR (gdb) frame create ADDR / frame address -create ADDR Thanks, Pedro Alves On 11/19/2014 06:49 AM, Yao Qi wrote: > Nan Xiao writes: > >> I use gdb to debug this program, and find 'frame n' command works OK: >> (gdb) bt >> #0 func1 (a=10) at a.c:5 >> #1 0x08050b67 in func2 (a=10) at a.c:11 >> #2 0x08050b89 in func3 (a=10) at a.c:18 >> #3 0x08050bb9 in main () at a.c:24 >> (gdb) frame 2 >> #2 0x08050b89 in func3 (a=10) at a.c:18 >> >> But when I want to use "frame addr" command, it seems not work well: >> >> (gdb) frame 0x08050bb9 >> #0 0x00000000 in ?? () >> (gdb) frame 0x08050b89 >> #0 0x00000000 in ?? () >> (gdb) frame 0x08050b92 >> #0 0x00000000 in ?? () >> >> How to use "frame addr" command? Thanks very much in advance! I can't >> find other reference except the manual. > > You pass the wrong address to command "frame". The addresses in the > output of "bt" command are the pc values in each frame. They are not > the address of frames. > > (gdb) help frame > Select and print a stack frame. > With no argument, print the selected stack frame. (See also "info frame"). > An argument specifies the frame to select. > It can be a stack frame number or the address of the frame. > ^^^^^^^^^^^^^^^^^^^^^^^^ > With argument, nothing is printed if input is coming from > a command file or a user-defined command. > > We should pass "the address of the frame" to command "frame", and it can > be got from command "info frame". > > (gdb) bt > #0 func1 (a=10) at 2.c:6 > #1 0x08048452 in func2 (a=10) at 2.c:12 > #2 0x08048474 in func3 (a=10) at 2.c:19 > #3 0x08048493 in main () at 2.c:25 > (gdb) info frame 2 > Stack frame at 0xbfffee70: > ^^^^^^^^^^ the address of the frame > eip = 0x8048474 in func3 (2.c:19); saved eip = 0x8048493 > called by frame at 0xbfffee90, caller of frame at 0xbfffee54 > source language c. > Arglist at 0xbfffee68, args: a=10 > Locals at 0xbfffee68, Previous frame's sp is 0xbfffee70 > Saved registers: > ebp at 0xbfffee68, eip at 0xbfffee6c > > (gdb) frame 0xbfffee70 > #2 0x08048474 in func3 (a=10) at 2.c:19 > 19 c = 2 * func2(a); >