From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 2073 invoked by alias); 6 Oct 2014 13:29:38 -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 2050 invoked by uid 89); 6 Oct 2014 13:29:37 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.4 required=5.0 tests=AWL,BAYES_00,FREEMAIL_FROM,RCVD_IN_DNSWL_LOW,SPF_PASS autolearn=ham version=3.3.2 X-Spam-User: qpsmtpd, 2 recipients X-HELO: mail-pd0-f181.google.com Received: from mail-pd0-f181.google.com (HELO mail-pd0-f181.google.com) (209.85.192.181) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES128-SHA encrypted) ESMTPS; Mon, 06 Oct 2014 13:29:36 +0000 Received: by mail-pd0-f181.google.com with SMTP id z10so3305726pdj.12 for ; Mon, 06 Oct 2014 06:29:34 -0700 (PDT) X-Received: by 10.66.182.227 with SMTP id eh3mr25173539pac.68.1412602174628; Mon, 06 Oct 2014 06:29:34 -0700 (PDT) Received: from ShengShiZhuChengdeMacBook-Pro.local ([223.72.65.50]) by mx.google.com with ESMTPSA id d1sm8072594pdd.34.2014.10.06.06.29.30 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 06 Oct 2014 06:29:33 -0700 (PDT) Message-ID: <54329A9A.9090303@gmail.com> Date: Mon, 06 Oct 2014 13:29:00 -0000 From: Chen Gang User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:31.0) Gecko/20100101 Thunderbird/31.1.2 MIME-Version: 1.0 To: Pedro Alves , Joel Brobecker CC: Mark Kettenis , amodra@gmail.com, gbenson@redhat.com, michael.sturm@intel.com, walfred.tedeschi@intel.com, binutils@sourceware.org, gdb-patches@sourceware.org Subject: Re: [PATCH] gdb/i387-tdep.c: Avoid warning for "-Werror=strict-overflow" References: <542EC11C.3020406@gmail.com> <201410031546.s93FknOM002165@glazunov.sibelius.xs4all.nl> <542EC9FC.8050107@gmail.com> <20141003164420.GK6927@adacore.com> <542EE1BF.7060203@redhat.com> <542F831D.1000502@gmail.com> <543255B6.7060509@redhat.com> In-Reply-To: <543255B6.7060509@redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-SW-Source: 2014-10/txt/msg00098.txt.bz2 On 10/6/14 16:41, Pedro Alves wrote: > On 10/04/2014 06:18 AM, Chen Gang wrote: >> >> OK, thanks. It is really one way, it is a little better than my original >> way. But for me, it is still not a good idea: it introduces a new macro >> and a new variable for each area (originally, it is only one statement). > > I see no problem with adding the new macro. We already have a ton > of similar macros, see i386-tdep.h and i387-tdep.h. Looks > like the existing I387_NUM_REGS is what we'd need here? > > BTC, OOC, did you try Joel's idea with the local variable? > In case Mark prefers that, it'd be good to know whether it works. > I can't seem to get my gcc to emit that warning. > > Combining both ideas, for clarity, we end up with something > like: > > int end; > > end = I387_ST0_REGNUM (tdep) + I387_NUM_REGS; > for (i = I387_ST0_REGNUM (tdep); i < end; i++) > > ... > > end = I387_XMM0_REGNUM (tdep) + I387_NUM_XMM_REGS (tdep); > for (i = I387_XMM0_REGNUM (tdep); i < end; i++) > > > That's way clearer to me than the existing: > That's way not quite bad to me than the existing: - It is easier understanding, although a little complex than origin. - For compiler, 'end' is simple enough to be sure to be optimized. - And I guess, compiler will understand, and will not worry about it. > for (i = I387_ST0_REGNUM (tdep); i < I387_XMM0_REGNUM (tdep); i++) > ... > for (i = I387_XMM0_REGNUM (tdep); i < I387_MXCSR_REGNUM (tdep); i++) > > anyway, which assumes the reader knows register numbers are > ordered like st -> xmm -> mxcrsr. > > If this works, I think it's my preference. > OK, thanks, at least, what you said is acceptable to me. If no any additional reply within this week (within 2014-10-12), I shall send patch v2 for it. >> For me, "-Werror" need always be optional, but not mandatory. > > It's mandatory only on development builds. -Werror is not on by > default on released GDBs. > OK, thanks. Thanks. -- Chen Gang Open, share, and attitude like air, water, and life which God blessed