From owner-freebsd-toolchain@freebsd.org  Wed Mar 13 11:57:45 2019
Return-Path: <owner-freebsd-toolchain@freebsd.org>
Delivered-To: freebsd-toolchain@mailman.ysv.freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1])
 by mailman.ysv.freebsd.org (Postfix) with ESMTP id 2AC79152FE32
 for <freebsd-toolchain@mailman.ysv.freebsd.org>;
 Wed, 13 Mar 2019 11:57:45 +0000 (UTC) (envelope-from wjw@digiware.nl)
Received: from smtp.digiware.nl (smtp.digiware.nl [IPv6:2001:4cb8:90:ffff::3])
 (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256
 bits)) (Client did not present a certificate)
 by mx1.freebsd.org (Postfix) with ESMTPS id A5353741ED
 for <freebsd-toolchain@freebsd.org>; Wed, 13 Mar 2019 11:57:44 +0000 (UTC)
 (envelope-from wjw@digiware.nl)
Received: from router.digiware.nl (localhost.digiware.nl [127.0.0.1])
 by smtp.digiware.nl (Postfix) with ESMTP id 9DFD21A5C7;
 Wed, 13 Mar 2019 12:57:36 +0100 (CET)
X-Virus-Scanned: amavisd-new at digiware.com
Received: from smtp.digiware.nl ([127.0.0.1])
 by router.digiware.nl (router.digiware.nl [127.0.0.1]) (amavisd-new,
 port 10024)
 with ESMTP id WLXFTp2kQrXg; Wed, 13 Mar 2019 12:57:36 +0100 (CET)
Received: from [192.168.10.9] (vaio [192.168.10.9])
 (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits))
 (No client certificate requested)
 by smtp.digiware.nl (Postfix) with ESMTPSA id 1776F1A5C6
 for <freebsd-toolchain@freebsd.org>; Wed, 13 Mar 2019 12:57:36 +0100 (CET)
To: FreeBSD Toolchain <freebsd-toolchain@freebsd.org>
From: Willem Jan Withagen <wjw@digiware.nl>
Subject: Is this a programming error, or a compiler error..
Message-ID: <bc4f8f4f-55c9-63ed-1ce8-b53d95a0696a@digiware.nl>
Date: Wed, 13 Mar 2019 12:57:33 +0100
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101
 Thunderbird/60.5.3
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 8bit
Content-Language: nl
X-BeenThere: freebsd-toolchain@freebsd.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Maintenance of FreeBSD's integrated toolchain
 <freebsd-toolchain.freebsd.org>
List-Unsubscribe: <https://lists.freebsd.org/mailman/options/freebsd-toolchain>, 
 <mailto:freebsd-toolchain-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-toolchain/>
List-Post: <mailto:freebsd-toolchain@freebsd.org>
List-Help: <mailto:freebsd-toolchain-request@freebsd.org?subject=help>
List-Subscribe: <https://lists.freebsd.org/mailman/listinfo/freebsd-toolchain>, 
 <mailto:freebsd-toolchain-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Wed, 13 Mar 2019 11:57:45 -0000

Hi,

I'm getting a crash in a Ceph test program in the following pice of code:

struct entity_addrvec_t {
   vector<entity_addr_t> v;
.....
   entity_addr_t legacy_addr() const {
     for (auto& a : v) {
       if (a.type == entity_addr_t::TYPE_LEGACY) {
         return a;
       }
     }
     return entity_addr_t();
   }
......

Where the loop is taken, even if v.size() == 0
So v content is pointing to random memory and itterating over the next 
pointer results in a crash.

I would expect the loop not to be executed....

--WjW