From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 89187 invoked by alias); 28 Aug 2018 18:49:14 -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 88996 invoked by uid 89); 28 Aug 2018 18:48:55 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-25.3 required=5.0 tests=AWL,BAYES_00,GIT_PATCH_0,GIT_PATCH_1,GIT_PATCH_2,GIT_PATCH_3,SPF_HELO_PASS autolearn=ham version=3.3.2 spammy= X-HELO: mx1.redhat.com Received: from mx3-rdu2.redhat.com (HELO mx1.redhat.com) (66.187.233.73) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Tue, 28 Aug 2018 18:48:54 +0000 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id B777C8076895; Tue, 28 Aug 2018 18:48:52 +0000 (UTC) Received: from [127.0.0.1] (ovpn04.gateway.prod.ext.ams2.redhat.com [10.39.146.4]) by smtp.corp.redhat.com (Postfix) with ESMTP id 42AE31010422; Tue, 28 Aug 2018 18:48:52 +0000 (UTC) Subject: Re: [PATCH 8/9] Avoid undefined behavior in expression dumping To: Tom Tromey , gdb-patches@sourceware.org References: <20180827145620.11055-1-tom@tromey.com> <20180827145620.11055-9-tom@tromey.com> From: Pedro Alves Message-ID: <939ad729-dc06-5f8f-e9a3-5a9b40af80ab@redhat.com> Date: Tue, 28 Aug 2018 18:49:00 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: <20180827145620.11055-9-tom@tromey.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-SW-Source: 2018-08/txt/msg00707.txt.bz2 On 08/27/2018 03:56 PM, Tom Tromey wrote: > -fsanitize=undefined pointed out undefined behavior in > dump_raw_expression like: > > runtime error: load of value 2887952, which is not a valid value for type 'exp_opcode' > > dump_raw_expression will try to print the opcode for each element of > the expression, even when it is not valid. To allow this, but have it > avoid undefined behavior, this patch sets the underlying type of enum > exp_opcode, and arranges for op_name to handle invalid opcodes more > nicely. Could you include before/after example output? > const char * > op_name (struct expression *exp, enum exp_opcode opcode) > { > + if (opcode >= OP_UNUSED_LAST) > + { > + char *cell = get_print_cell (); > + xsnprintf (cell, PRINT_CELL_SIZE, "unknown opcode: %d", int (opcode)); If the underlying type is unsigned, what is the rationale for printing it as signed? > + return cell; > + } > return exp->language_defn->la_exp_desc->op_name (opcode); > } > > diff --git a/gdb/expression.h b/gdb/expression.h > index 9f26bb8d60b..db572efe2a3 100644 > --- a/gdb/expression.h > +++ b/gdb/expression.h > @@ -39,7 +39,7 @@ > and skip that many. Strings, like numbers, are indicated > by the preceding opcode. */ > > -enum exp_opcode > +enum exp_opcode : uint8_t > { > #define OP(name) name , > > Thanks, Pedro Alves