From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 22582 invoked by alias); 14 May 2013 15:24:10 -0000 Mailing-List: contact gdb-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-owner@sourceware.org Received: (qmail 22560 invoked by uid 89); 14 May 2013 15:24:10 -0000 X-Spam-SWARE-Status: No, score=-3.3 required=5.0 tests=AWL,BAYES_00,FREEMAIL_FROM,KHOP_THREADED,RCVD_IN_DNSWL_LOW,RCVD_IN_HOSTKARMA_YE,SPF_PASS autolearn=ham version=3.3.1 Received: from mail-ve0-f181.google.com (HELO mail-ve0-f181.google.com) (209.85.128.181) by sourceware.org (qpsmtpd/0.84/v0.84-167-ge50287c) with ESMTP; Tue, 14 May 2013 15:24:09 +0000 Received: by mail-ve0-f181.google.com with SMTP id pb11so692240veb.26 for ; Tue, 14 May 2013 08:24:07 -0700 (PDT) MIME-Version: 1.0 X-Received: by 10.52.120.83 with SMTP id la19mr18612428vdb.58.1368545047779; Tue, 14 May 2013 08:24:07 -0700 (PDT) Received: by 10.220.175.131 with HTTP; Tue, 14 May 2013 08:24:07 -0700 (PDT) In-Reply-To: <15482.1368542282@usendtaylorx2l> References: <18975.1368456346@usendtaylorx2l> <20130513145224.GY1377@tucnak.redhat.com> <15482.1368542282@usendtaylorx2l> Date: Tue, 14 May 2013 15:24:00 -0000 Message-ID: Subject: Re: stabs changes for 64 bit targets From: David Edelsohn To: David Taylor Cc: Jakub Jelinek , "gcc@gcc.gnu.org" , "gdb@sourceware.org" , "binutils@zalov.cz" Content-Type: text/plain; charset=ISO-8859-1 X-SW-Source: 2013-05/txt/msg00057.txt.bz2 On Tue, May 14, 2013 at 10:38 AM, David Taylor wrote: > Jakub Jelinek wrote: > >> On Mon, May 13, 2013 at 10:45:46AM -0400, David Taylor wrote: >> > There are problems when using current STABS debug format for 64 bit >> > targets. >> >> Why are you considering extending STABS at this point? >> STABS support might very well be dropped altogether from GCC 4.9 or the next >> release, people just should use DWARF[234] everywhere. > > There are multiple reasons. One of the big reasons is... > > Prior to GCC 4.7, DWARF is too verbose compared to STABS. > > In STABS, all strings go into the string table; identical strings get > put into the table just once. > > In DWARF, prior to GCC 4.7, macro strings do not go into the string > table. If 1000 files all include a given header file, each #define in > that header gets its own string in the debug information -- so the > string is present 1000 times. GCC 4.7 (DWARF4) fixes this. > > We have STABS extensions (posted years ago, but never merged) that > record macros in the STABS debug information -- at the -g3 level, just > like for DWARF. Please keep in mind that AIX continues to use STABS with its XCOFF file format, so please do not make changes to STABS under the assumption that you are the only producer and consumer. AIX added support for DWARF and I believe that there are some patches to support DWARF on AIX from Adacore, but those have not been merged into FSF GCC, Binutils and GDB yet. Thanks, David