From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 22865 invoked by alias); 18 Feb 2011 17:53:38 -0000 Received: (qmail 22847 invoked by uid 22791); 18 Feb 2011 17:53:36 -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 X-Spam-Check-By: sourceware.org Received: from mail-qw0-f41.google.com (HELO mail-qw0-f41.google.com) (209.85.216.41) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Fri, 18 Feb 2011 17:53:31 +0000 Received: by qwd7 with SMTP id 7so552872qwd.0 for ; Fri, 18 Feb 2011 09:53:29 -0800 (PST) MIME-Version: 1.0 Received: by 10.224.47.75 with SMTP id m11mr887294qaf.249.1298051607741; Fri, 18 Feb 2011 09:53:27 -0800 (PST) Received: by 10.224.61.18 with HTTP; Fri, 18 Feb 2011 09:53:27 -0800 (PST) In-Reply-To: <4D5E37C702000078000329DE@vpn.id2.novell.com> References: <4D5C2DD2.10608@zytor.com> <4D5CEBDE02000078000325A2@vpn.id2.novell.com> <20110217142916.GI13037@sunsite.ms.mff.cuni.cz> <20110217152233.GB11346@atrey.karlin.mff.cuni.cz> <20110217154452.GA18799@kam.mff.cuni.cz> <4D5D56B70200007800032747@vpn.id2.novell.com> <4D5E37C702000078000329DE@vpn.id2.novell.com> Date: Fri, 18 Feb 2011 17:53:00 -0000 Message-ID: Subject: Re: x32 psABI draft version 0.2 From: "H.J. Lu" To: Jan Beulich Cc: GCC Development , x32-abi@googlegroups.com, Jakub Jelinek , Binutils , GNU C Library , Jan Hubicka , "H. Peter Anvin" Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable X-IsSubscribed: yes Mailing-List: contact binutils-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: binutils-owner@sourceware.org X-SW-Source: 2011-02/txt/msg00242.txt.bz2 On Fri, Feb 18, 2011 at 12:11 AM, Jan Beulich wrote: >>>> On 17.02.11 at 18:59, "H.J. Lu" wrote: >> On Thu, Feb 17, 2011 at 8:11 AM, Jan Beulich wrote: >>>>>> On 17.02.11 at 16:49, "H.J. Lu" wrote: >>>> On Thu, Feb 17, 2011 at 7:44 AM, Jan Hubicka wrote: >>>>>> > According to Mozilla folks however REL+RELA scheme used by EABI le= ads >>>>>> > to significandly smaller libxul.so size >>>>>> > >>>>>> > According to http://glandium.org/blog/?p=3D1177 the difference is = about 4-5MB >>>>>> > (out of approximately 20-30MB shared lib) >>>>>> >>>>>> This is orthogonal to x32 psABI. >>>>> >>>>> Understood. =A0I am just pointing out that x86-64 Mozilla suffers fro= m startup >>>>> problems (extra 5MB of disk read needed) compared to both x86 and ARM= EABI >>>>> because x86-64 ABI is RELA only. If x86-64 ABI was REL+RELA like EABI= is, we >>>>> would not have this problem here. >>>>> >>>> >>>> If people want to see REL+RELA in x32, they have to contribute codes. >>> >>> That's exactly the wrong way round: First the specification has to allow >>> for (but not require) it, and only then does it make sense to write cod= e. >>> >> >> No, it has to be supported at least by static linker and dynamic >> linker. Otherwise, no one can use it. > > I'm afraid I have to disagree: ELF (and the psABI) is not specific to > a particular OS, and hence it allowing something doesn't mean the > OS ABI may not restrict it. Hence the psABI first has to at least not > forbid something (as it currently does for REL on x86-64), in order > for an implementation of that something to make sense. > > Jan > > How about only allowing REL relocations in executables and DSOes? BTW, the psABI source is available on hjl/x32 banch at http://git.kernel.org/?p=3Ddevel/binutils/hjl/x86-64-psabi.git;a=3Dsummary --=20 H.J.