From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-patches-return-294267-listarch-gcc-patches=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 7687 invoked by alias); 12 Jun 2011 17:06:21 -0000
Received: (qmail 7679 invoked by uid 22791); 12 Jun 2011 17:06:21 -0000
X-SWARE-Spam-Status: No, hits=-2.3 required=5.0	tests=AWL,BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,RCVD_IN_DNSWL_LOW,RFC_ABUSE_POST
X-Spam-Check-By: sourceware.org
Received: from mail-qw0-f47.google.com (HELO mail-qw0-f47.google.com) (209.85.216.47)    by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Sun, 12 Jun 2011 17:06:07 +0000
Received: by qwh5 with SMTP id 5so2161000qwh.20        for <gcc-patches@gcc.gnu.org>; Sun, 12 Jun 2011 10:06:06 -0700 (PDT)
MIME-Version: 1.0
Received: by 10.229.131.32 with SMTP id v32mr3136193qcs.35.1307898366264; Sun, 12 Jun 2011 10:06:06 -0700 (PDT)
Received: by 10.229.47.78 with HTTP; Sun, 12 Jun 2011 10:06:06 -0700 (PDT)
In-Reply-To: <20110612163302.GD19441@kam.mff.cuni.cz>
References: <20110611125552.GA25068@kam.mff.cuni.cz>	<BANLkTim23fOqkBS+QKfmmpExBrAXfTNdAw@mail.gmail.com>	<BANLkTik8zti5+FwGHX=j3_MKqEgAgxPZAA@mail.gmail.com>	<20110612145443.GA7920@kam.mff.cuni.cz>	<BANLkTi=dv6ZauuJzSy9vgN713cCLg8ObvA@mail.gmail.com>	<20110612163302.GD19441@kam.mff.cuni.cz>
Date: Sun, 12 Jun 2011 17:46:00 -0000
Message-ID: <BANLkTikJjv32Oji3_jBKX2DcvWpGO3OsDQ@mail.gmail.com>
Subject: Re: Cgraph alias reorg 15/14 (New infrastructure for same body aliases)
From: "H.J. Lu" <hjl.tools@gmail.com>
To: Jan Hubicka <hubicka@ucw.cz>
Cc: gcc-patches@gcc.gnu.org
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable
X-IsSubscribed: yes
Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm
Precedence: bulk
List-Id: <gcc-patches.gcc.gnu.org>
List-Archive: <http://gcc.gnu.org/ml/gcc-patches/>
List-Post: <mailto:gcc-patches@gcc.gnu.org>
List-Help: <mailto:gcc-patches-help@gcc.gnu.org>
Sender: gcc-patches-owner@gcc.gnu.org
X-SW-Source: 2011-06/txt/msg00952.txt.bz2

On Sun, Jun 12, 2011 at 9:33 AM, Jan Hubicka <hubicka@ucw.cz> wrote:
>> On Sun, Jun 12, 2011 at 7:54 AM, Jan Hubicka <hubicka@ucw.cz> wrote:
>> >>
>> >> This also pretty much destroyed C++ for ia32:
>> >>
>> >> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D49378
>> >> http://gcc.gnu.org/ml/gcc-regression/2011-06/msg00159.html
>> >
>> > Hi,
>> > It seems somewhat amazing that we hit kernel sensitive miscompilation =
here.
>> > The problem most probably is the fact that thunks and functions with t=
hunks can become
>> > local. This is correct since thunks are represented as direct calls no=
w, but this
>> > makes i386 to use local ABI when calling or compiling them.
>> >
>>
>> For x86-64, we use the same ABI for local and global. But RAX seems
>> used and uninitialized in thunk.
> 000000000006d270 <_ZN12_GLOBAL__N_121system_error_categoryD0Ev>:
> =A0 6d270: =A0 =A0 =A0 48 8d 05 79 d4 27 00 =A0 =A0lea =A0 =A00x27d479(%r=
ip),%rax =A0 =A0 =A0 =A0#
> 2ea6f0 <_ZTVN12_GLOBAL__N_121system_error_categoryE+0x10>
> =A0 6d277: =A0 =A0 =A0 53 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0push=
 =A0 %rbx
> =A0 6d278: =A0 =A0 =A0 48 89 fb =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0mov =A0 =
=A0%rdi,%rbx
> =A0 6d27b: =A0 =A0 =A0 48 89 07 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0mov =A0 =
=A0%rax,(%rdi)
> =A0 6d27e: =A0 =A0 =A0 e8 55 a0 fe ff =A0 =A0 =A0 =A0 =A0callq =A0572d8
> <_ZNSt14error_categoryD2Ev@plt>
> =A0 6d283: =A0 =A0 =A0 48 89 df =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0mov =A0 =
=A0%rbx,%rdi
> =A0 6d286: =A0 =A0 =A0 5b =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0pop =
=A0 =A0%rbx
> =A0 6d287: =A0 =A0 =A0 e9 2c 9d fe ff =A0 =A0 =A0 =A0 =A0jmpq =A0 56fb8 <=
_ZdlPv@plt>
> =A0 6d28c: =A0 =A0 =A0 90 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0nop
> =A0 6d28d: =A0 =A0 =A0 90 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0nop
> =A0 6d28e: =A0 =A0 =A0 90 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0nop
> =A0 6d28f: =A0 =A0 =A0 90 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0nop
>
> I don't see uinitialized RAX here. =A0It is set by the first LEA

You are right.

--=20
H.J.