From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 26980 invoked by alias); 29 Jun 2011 10:17:33 -0000 Received: (qmail 26971 invoked by uid 22791); 29 Jun 2011 10:17:33 -0000 X-SWARE-Spam-Status: No, hits=-2.0 required=5.0 tests=AWL,BAYES_00,MSGID_MULTIPLE_AT,RCVD_IN_DNSWL_LOW X-Spam-Check-By: sourceware.org Received: from service87.mimecast.com (HELO service87.mimecast.com) (94.185.240.25) by sourceware.org (qpsmtpd/0.43rc1) with SMTP; Wed, 29 Jun 2011 10:17:18 +0000 Received: from cam-owa1.Emea.Arm.com (fw-tnat.cambridge.arm.com [217.140.96.21]) by service87.mimecast.com; Wed, 29 Jun 2011 11:17:16 +0100 Received: from Terrysh02 ([10.1.255.212]) by cam-owa1.Emea.Arm.com with Microsoft SMTPSVC(6.0.3790.0); Wed, 29 Jun 2011 11:17:14 +0100 From: "Terry Guo" To: "'Yao Qi'" Cc: , References: <000901cc34bc$fd1aa6a0$f74ff3e0$@guo@arm.com> <000101cc35fb$8d45ff60$a7d1fe20$@guo@arm.com> <4E0AB9B3.8060104@codesourcery.com> <000501cc362a$2e7f9020$8b7eb060$@guo@arm.com> <4E0ADB87.20807@codesourcery.com> <45520D6299C11E4588128526465332BB0D0C8B1246@SAROVARA.Asiapac.Arm.com> <4E0AF7A6.1040800@codesourcery.com> In-Reply-To: <4E0AF7A6.1040800@codesourcery.com> Subject: RE: [PATCH] Fix that different function breakpoints are set at same pc address (PR gdb/12703) Date: Wed, 29 Jun 2011 10:17:00 -0000 Message-ID: <000701cc3645$b5004980$1f00dc80$@guo@arm.com> MIME-Version: 1.0 X-MC-Unique: 111062911171603001 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-IsSubscribed: yes 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 X-SW-Source: 2011-06/txt/msg00441.txt.bz2 > -----Original Message----- > From: Yao Qi [mailto:yao@codesourcery.com] > Sent: Wednesday, June 29, 2011 6:00 PM > To: Terry Guo > Cc: gdb-patches@sourceware.org; pedro@codesourcery.com > Subject: Re: [PATCH] Fix that different function breakpoints are set at > same pc address (PR gdb/12703) >=20 > On 06/29/2011 04:47 PM, Terry Guo wrote: > > Hi, > > > > First if you look at the generated binary code, I thought it is a > valid case. After performing the function test, it will fall into > function bar which is a normal function. At least my case can run > correctly on QEMU. It is very likely for people to write program in > assembly code like: > > > > main: > > b test > > > > test: > > movs r5, #10 > > bar: > > push....... > > ......... > > >=20 > We are lucky here GCC places bar next to function test physically, but > gcc may also place function test and bar in other layout, like >=20 > main: > b test >=20 > bar: > push ... >=20 > test: > moves r5, #10 >=20 > After test, processor will run some instructions that we don't know. > IMO, it is incorrect. >=20 > > You cannot say this is a invalid program. If you have concern about > attribute NAKED, I can rewrite it in assembly code. > > >=20 > I have no concern on attribute NAKED here. I know that GCC will "luckily" place code like that. That's why I just post assembly code first. The key point here is the program can be written in=20 assembly code and in this way the function position can be ensured without the help of luck. is my understanding right?=20 I use "naked" here in C code because I am lazy to write assembly code. You can omit the "naked" in C and look at the case as a case written in assembly code. >=20 > > Second, we all know that current prologue analyzer cannot handle all > cases. My patch only intends to be a worthwhile supplement for cases > that beyond the prologue analyzer capability. > > > > Third, I also have strong interesting to enhance prologue analyze. I > suggest we use another thread to discuss how to enhance prologue > analyzer to handle all possible cases. And leave this one to discuss > whether is it worthwhile to have my patch. >=20 > OK, thanks for your clarification. If you think your test case is > correct, please send the patch again, and the right people can > review/approve your patch. > > -- > Yao (=E9=BD=90=E5=B0=A7) >=20 > P.S. 1. could you please set up your mail client to newline your mail > automatically? It is hard to read one paragraph in one line. 2. > could > you reply mail with quoted context? Thanks for your reminding. BR, Terry=20