From owner-freebsd-dtrace@freebsd.org Mon Apr 17 20:46:31 2017 Return-Path: Delivered-To: freebsd-dtrace@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id EA885D423A0; Mon, 17 Apr 2017 20:46:31 +0000 (UTC) (envelope-from gnn@neville-neil.com) Received: from relay4-d.mail.gandi.net (relay4-d.mail.gandi.net [IPv6:2001:4b98:c:538::196]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id B763869; Mon, 17 Apr 2017 20:46:31 +0000 (UTC) (envelope-from gnn@neville-neil.com) Received: from [172.20.10.2] (unknown [IPv6:2607:fb90:76a:e0fb:d8d8:6ef3:8e02:11ca]) (Authenticated sender: gnn@neville-neil.com) by relay4-d.mail.gandi.net (Postfix) with ESMTPSA id 8D0DA1720AF; Mon, 17 Apr 2017 22:46:27 +0200 (CEST) From: "George Neville-Neil" To: "Sevan / Venture37" Cc: "Ryan Stone" , freebsd-gecko@freebsd.org, "Jan Beich" , "freebsd-dtrace@freebsd.org" Subject: Re: DTrace issues? Date: Mon, 17 Apr 2017 16:46:25 -0400 Message-ID: <27FA81DC-3939-4798-AB4D-C4BBE86B6AAB@neville-neil.com> In-Reply-To: References: <3CEE1970-719B-42D1-A95A-FEAD3F375A30@neville-neil.com> <20170212191826.5599A45EA@freefall.freebsd.org> <77416dea-1e9d-4911-b5d0-2ebac227af7e@Spark> <76897620-E958-4AE2-9B6C-062C59526614@neville-neil.com> MIME-Version: 1.0 Content-Type: text/plain; format=flowed; markup=markdown X-Mailer: MailMate (1.9.6r5347) X-BeenThere: freebsd-dtrace@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: "A discussion list for developers working on DTrace in FreeBSD." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 17 Apr 2017 20:46:32 -0000 On 17 Apr 2017, at 16:28, Sevan / Venture37 wrote: > On 17 April 2017 at 20:54, Ryan Stone wrote: >> On Sat, Apr 15, 2017 at 10:50 AM, George Neville-Neil >> >> wrote: >> >>> >>> Can you explain this grief? What is the problem? >>> >>> Best, >>> George >>> >> >> dtrace -G requires the ability to modify the object files in-place >> before >> linking. This causes havoc if the objects are in .a archives (dtrace >> can't >> read those) or if the objects need to be linked into multiple >> binaries. It >> also destroys the ability to do an incremental build, as dtrace -G >> can't be >> run on the same object twice. >> >> The whole process is really a hack. The build actions done by dtrace >> should be done by the compiler and linker instead. Getting the >> linker to >> support the process would go a long way, as then dtrace -G could be >> run on >> individual objects and most of my complaints go away. > > Not to detract from the issue with the -G flag, I just wanted to > highlight that it's used for ELF binaries, until Apple switches away > from Mach-o, this wont be an issue there (dtrace on OS X does not > feature the -G flag). > > Well at least I now "get" the issue. Thanks. Best, George