From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 4706 invoked by alias); 29 Aug 2018 00:45:05 -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 4667 invoked by uid 89); 29 Aug 2018 00:45:03 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-2.9 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_NONE,SPF_HELO_PASS autolearn=ham version=3.3.2 spammy= X-HELO: gateway24.websitewelcome.com Received: from gateway24.websitewelcome.com (HELO gateway24.websitewelcome.com) (192.185.51.172) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Wed, 29 Aug 2018 00:45:01 +0000 Received: from cm10.websitewelcome.com (cm10.websitewelcome.com [100.42.49.4]) by gateway24.websitewelcome.com (Postfix) with ESMTP id 5F4D37B5A4 for ; Tue, 28 Aug 2018 19:45:00 -0500 (CDT) Received: from box5379.bluehost.com ([162.241.216.53]) by cmsmtp with SMTP id uobCfGpoVBcCXuobNflB6N; Tue, 28 Aug 2018 19:44:59 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=tromey.com; s=default; h=Content-Type:MIME-Version:Message-ID:In-Reply-To:Date: References:Subject:Cc:To:From:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=XwFlkH9gKvtk7mM8GF0c6j/gA4ESricxd+SfedzHXVI=; b=x/dsNsgU14CDKfRHuRhxlrnmFk stMwuqwihG+p55p+c+NwPL/caiUpqWIcqcN7KmEC5wPb4CDNGrurNOv2nLbeSjv8GWmjfwuXrhPf+ TgozLgFUKh5VMG6kDrsbC4PQn; Received: from 75-166-85-72.hlrn.qwest.net ([75.166.85.72]:45918 helo=bapiya) by box5379.bluehost.com with esmtpsa (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.91) (envelope-from ) id 1fuobC-003aWA-7V; Tue, 28 Aug 2018 19:44:42 -0500 From: Tom Tromey To: Pedro Alves Cc: Tom Tromey , gdb-patches@sourceware.org Subject: Re: [PATCH 0/9] Add UBSan to the build References: <20180827145620.11055-1-tom@tromey.com> <152ef6ac-cd48-72be-6fae-9397bca2c8b8@redhat.com> Date: Wed, 29 Aug 2018 00:45:00 -0000 In-Reply-To: <152ef6ac-cd48-72be-6fae-9397bca2c8b8@redhat.com> (Pedro Alves's message of "Tue, 28 Aug 2018 20:03:19 +0100") Message-ID: <87tvnevw5i.fsf@tromey.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-SW-Source: 2018-08/txt/msg00723.txt.bz2 >>>>> "Pedro" == Pedro Alves writes: Pedro> I think this is a good idea. On enabling this by default on devel Pedro> builds, do you have a sense of CPU/memory overhead this introduces? I have no idea about the CPU. It doesn't seem notably slower to me but I am not sure I would really notice. I don't think -fsanitize=undefined has notable memory overhead. I believe it just introduces checks at spots where undefined behavior might be possible. It does increase the size of gdb: size before: text data bss dec hex filename 23070184 2372034 323664 25765882 18927fa gdb size after: text data bss dec hex filename 26879230 9135154 324688 36339072 22a7d80 gdb I think this isn't so important because it's only for development mode and because it can be turned off if need be. Though, let's not oversell it -- UB sanitization didn't catch anything very important. Address sanitizer, on the other hand, did; and if I can fix that last bug I would like to give -fsanitize=address the same treatment as was done here. Tom