From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 53189 invoked by alias); 17 Jan 2018 18:03:06 -0000 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 Received: (qmail 51810 invoked by uid 89); 17 Jan 2018 18:03:04 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-0.9 required=5.0 tests=BAYES_00,KAM_LAZY_DOMAIN_SECURITY,SPF_HELO_PASS,T_RP_MATCHES_RCVD autolearn=no version=3.3.2 spammy=Hx-languages-length:2382 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 ESMTP; Wed, 17 Jan 2018 18:03:03 +0000 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 2B4E67F7B9; Wed, 17 Jan 2018 18:03:02 +0000 (UTC) Received: from localhost (unused-10-15-17-193.yyz.redhat.com [10.15.17.193]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D9F2A85585; Wed, 17 Jan 2018 18:03:01 +0000 (UTC) From: Sergio Durigan Junior To: Pedro Alves Cc: GDB Patches , Eli Zaretskii Subject: Re: [PATCH] Fix unitialized warning on gdb/typeprint.c:whatis_exp References: <87po69zkxe.fsf@redhat.com> <20180116203239.27787-1-sergiodj@redhat.com> Date: Wed, 17 Jan 2018 18:03:00 -0000 In-Reply-To: (Pedro Alves's message of "Wed, 17 Jan 2018 16:47:51 +0000") Message-ID: <87fu74fjmy.fsf@redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-IsSubscribed: yes X-SW-Source: 2018-01/txt/msg00356.txt.bz2 On Wednesday, January 17 2018, Pedro Alves wrote: > On 01/16/2018 08:32 PM, Sergio Durigan Junior wrote: >> This simple patch initializes "struct value *val" to NULL, which >> silences a when compiling GDB with certain GCC versions. > > Please include a representative paste of warnings in git logs. > It makes it easier to see what a patch/commit is about. Will do. >> This warning is technically incorrect, because there is now way that >> "val" will be used unitialized if you look at the code flow, but it's >> a simple "fix" and doesn't do any harm. > > No, it's not incorrect. It's showing a real bug. Try, e.g.: > > (gdb) set print object on > (gdb) whatis some_structure_type > > Thread 1 "gdb" received signal SIGSEGV, Segmentation fault. > 0x00000000005dda90 in check_typedef (type=0x6120736573756170) at src/gdb/gdbtypes.c:2388 > 2388 int instance_flags = TYPE_INSTANCE_FLAGS (type); > (top-gdb) bt > #0 0x00000000005dda90 in check_typedef(type*) (type=0x6120736573756170) at src/gdb/gdbtypes.c:2388 > #1 0x00000000005e63fb in gnuv3_rtti_type(value*, int*, LONGEST*, int*) > (value=0xdf21b7, full_p=0x7fffffffd180, top_p=0x7fffffffd188, > using_enc_p=0x7fffffffd184) at src/gdb/gnu-v3-abi.c:293 > #2 0x000000000055f7d8 in value_rtti_type(value*, int*, long*, int*) (v=0xdf21b7, full=0x7fffffffd180, top=0x7fffffffd188, using_enc=0x7fffffffd184) at src/gdb/cp-abi.c:117 > #3 0x00000000006cc61f in whatis_exp(char const*, int) (exp=, show=-1) at src/gdb/typeprint.c:515 > #4 0x0000000000472462 in cmd_func(cmd_list_element*, char const*, int) (cmd=, args=, from_tty=) > at src/gdb/cli/cli-decode.c:1886 > #5 0x00000000006b833a in execute_command(char const*, int) (p=, from_tty=1) at src/gdb/top.c:630 > #6 0x00000000005c0f8c in command_handler(char const*) (command=0xdf21b0 "whatis siginfo_t") at src/gdb/event-top.c:583 > #7 0x00000000005c12d8 in command_line_handler(char*) (rl=) at /home/pedro/gdb/mygit/src/gdb/event-top.c:774 > ... Ah, I totally missed that. Sorry about jumping into the conclusion that it was incorrect. I'll try to investigate what's happening here. -- Sergio GPG key ID: 237A 54B1 0287 28BF 00EF 31F4 D0EB 7628 65FC 5E36 Please send encrypted e-mail if possible http://sergiodj.net/