From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 3375 invoked by alias); 24 Mar 2014 07:57:08 -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 3365 invoked by uid 89); 24 Mar 2014 07:57:07 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.8 required=5.0 tests=AWL,BAYES_50,RP_MATCHES_RCVD,SPF_PASS autolearn=ham version=3.3.2 X-HELO: mga11.intel.com Received: from mga11.intel.com (HELO mga11.intel.com) (192.55.52.93) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Mon, 24 Mar 2014 07:57:06 +0000 Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga102.fm.intel.com with ESMTP; 24 Mar 2014 00:57:05 -0700 X-ExtLoop1: 1 Received: from irsmsx101.ger.corp.intel.com ([163.33.3.153]) by fmsmga001.fm.intel.com with ESMTP; 24 Mar 2014 00:57:04 -0700 Received: from irsmsx152.ger.corp.intel.com (163.33.192.66) by IRSMSX101.ger.corp.intel.com (163.33.3.153) with Microsoft SMTP Server (TLS) id 14.3.123.3; Mon, 24 Mar 2014 07:55:34 +0000 Received: from irsmsx104.ger.corp.intel.com ([169.254.5.2]) by IRSMSX152.ger.corp.intel.com ([169.254.6.180]) with mapi id 14.03.0123.003; Mon, 24 Mar 2014 07:55:34 +0000 From: "Metzger, Markus T" To: Jan Kratochvil CC: "gdb-patches@sourceware.org" , "Pedro Alves (palves@redhat.com)" Subject: RE: [PATCH 2/2] btrace: avoid symbol lookup Date: Mon, 24 Mar 2014 07:57:00 -0000 Message-ID: References: <1394182665-14164-1-git-send-email-markus.t.metzger@intel.com> <1394182665-14164-3-git-send-email-markus.t.metzger@intel.com> <20140310214252.GA3105@host2.jankratochvil.net> <20140321172215.GA15215@host2.jankratochvil.net> In-Reply-To: <20140321172215.GA15215@host2.jankratochvil.net> Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-IsSubscribed: yes X-SW-Source: 2014-03/txt/msg00567.txt.bz2 > -----Original Message----- > From: Jan Kratochvil [mailto:jan.kratochvil@redhat.com] > Sent: Friday, March 21, 2014 6:22 PM > To: Metzger, Markus T > Cc: gdb-patches@sourceware.org; Pedro Alves (palves@redhat.com) > Subject: Re: [PATCH 2/2] btrace: avoid symbol lookup >=20 > On Tue, 11 Mar 2014 11:08:43 +0100, Metzger, Markus T wrote: > > What's missing is a "fast fail", i.e. quickly determine that we won't f= ind any > > symbol for this PC. I won't be able to do this in a reasonable amount = of > time, > > though, so I thought this patch is a compromise between functionality a= nd > > performance. >=20 > I do not think providing incorrect behavior for performance reasons is a = valid > tradeoff. The right way would be to fix the DWARF lookups to be fast > enough. I realized after I sent this that the word 'functionality' was not chosen w= ell. The only actual change in functionality I was able to observe was missing parens for the main function, i.e. it had been printed "main()" and is now printed "main". That's because its language is 'auto' and not 'c' or 'cpp'. I believe that this could and should be fixed by fixing up the language of the main mini-symbol to align with the language of other symbols in the same object file. I think the compromise is rather between a nice, general solution that benefits everybody and a local solution that only benefits btrace and that might make supporting inline functions more difficult in the future. Regards, Markus. Intel GmbH Dornacher Strasse 1 85622 Feldkirchen/Muenchen, Deutschland Sitz der Gesellschaft: Feldkirchen bei Muenchen Geschaeftsfuehrer: Christian Lamprechter, Hannes Schwaderer, Douglas Lusk Registergericht: Muenchen HRB 47456 Ust.-IdNr./VAT Registration No.: DE129385895 Citibank Frankfurt a.M. (BLZ 502 109 00) 600119052