From owner-freebsd-dtrace@FreeBSD.ORG Wed Mar 12 04:50:51 2014 Return-Path: Delivered-To: freebsd-dtrace@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id A23A5129 for ; Wed, 12 Mar 2014 04:50:51 +0000 (UTC) Received: from cain.gsoft.com.au (cain.gsoft.com.au [203.31.81.10]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id EF5CA136 for ; Wed, 12 Mar 2014 04:50:50 +0000 (UTC) Received: from ur.dons.net.au (ppp118-210-56-74.lns20.adl2.internode.on.net [118.210.56.74]) (authenticated bits=0) by cain.gsoft.com.au (8.14.4/8.14.3) with ESMTP id s2C4oIuP025262 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=NO); Wed, 12 Mar 2014 15:20:26 +1030 (CST) (envelope-from doconnor@gsoft.com.au) Subject: Re: dtracing static symbols Mime-Version: 1.0 (Mac OS X Mail 7.2 \(1874\)) Content-Type: multipart/signed; boundary="Apple-Mail=_32394B83-8C01-47BD-B503-BE1BCB65F7C7"; protocol="application/pgp-signature"; micalg=pgp-sha1 From: "Daniel O'Connor" In-Reply-To: <1394599542.80116.YahooMailBasic@web192602.mail.sg3.yahoo.com> Date: Wed, 12 Mar 2014 15:20:17 +1030 Message-Id: References: <1394599542.80116.YahooMailBasic@web192602.mail.sg3.yahoo.com> To: Prashanth Kumar X-Mailer: Apple Mail (2.1874) X-Spam-Score: 0.163 () BAYES_00,RDNS_DYNAMIC X-Scanned-By: MIMEDefang 2.67 on 203.31.81.10 Cc: Robert Mustacchi , freebsd-dtrace@freebsd.org X-BeenThere: freebsd-dtrace@freebsd.org X-Mailman-Version: 2.1.17 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: Wed, 12 Mar 2014 04:50:51 -0000 --Apple-Mail=_32394B83-8C01-47BD-B503-BE1BCB65F7C7 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=iso-8859-1 On 12 Mar 2014, at 15:15, Prashanth Kumar wrote: > If you run=20 > # env DTRACE_DEBUG=3D1 dtrace -Ppid\$target -l -c ./static > you will notice that lot of probe creation will fail, also no probes = are created for instruction offsets. > you will have to update the libproc library and fasttrap code to = trace all the=20 > functions.=20 I don't really care about the function offsets, just static functions.=20= Or are you suggesting updating libproc and the fasttrap code will allow = that (as well as instruction offsets)? THanks. > -------------------------------------------- > On Wed, 12/3/14, Daniel O'Connor wrote: >=20 > Subject: Re: dtracing static symbols > To: "Robert Mustacchi" > Cc: freebsd-dtrace@freebsd.org > Date: Wednesday, 12 March, 2014, 2:54 AM >=20 >=20 > On 12 Mar 2014, at 2:30, Robert Mustacchi > wrote: >> On 03/10/2014 10:34 PM, Daniel O'Connor wrote: >>>=20 >>> On 11 Mar 2014, at 15:34, Prashanth Kumar > wrote: >>>> If the binary being traced has static symbols > in its symbol table, DTrace should >>>> be able to trace the function. Can you describe > the example where you found this >>>> difference in FreeBSD and OSX? >>>=20 >>> Unfortunately the static symbols don't show up in > the symbol table (as shown by nm). >>>=20 >>> Is there a compile or link flag which will change > that? >>=20 >> Because it's a static function the compiler may inline > it, which may be >> why you don't actually see an entry in nm nor that it > can be found by >> DTrace. You'll want to look at the disassembled output > of your program >> to see if it was inlined. Different compilers can and > will do different >> things. There generally are flags you can pass to the > compiler to tell >> it not to inline it, but that's compiler specific. >=20 > I just realised that my test contradicted the statement I > made earlier.. > However I checked my test program (static.c) and it the > functions definitely appear in the symbol table. > [mdtest 21:13] ~ >nm static|egrep '(foo|bar)' > 0000000000400600 T bar > 0000000000400620 t foo >=20 > I also added the noinline attribute for good measure. >=20 > It seems that _nothing_ shows up for executables, only > shared libraries, this is OK for me since my code resides in > a library but it is a bit surprised nonetheless.. >=20 >>> (I'm not sure what the various numbers mean) >>=20 >> The pid provider can instrument any instruction in a > function, those are >> the instruction offsets. >=20 > Ahh, thanks. >=20 > -- > Daniel O'Connor software and network engineer > for Genesis Software - http://www.gsoft.com.au > "The nice thing about standards is that there > are so many of them to choose from." > -- Andrew Tanenbaum > GPG Fingerprint - 5596 B766 97C0 0E94 4347 295E E593 DC20 > 7B3F CE8C >=20 >=20 >=20 >=20 >=20 >=20 >=20 >=20 -- Daniel O'Connor software and network engineer for Genesis Software - http://www.gsoft.com.au "The nice thing about standards is that there are so many of them to choose from." -- Andrew Tanenbaum GPG Fingerprint - 5596 B766 97C0 0E94 4347 295E E593 DC20 7B3F CE8C --Apple-Mail=_32394B83-8C01-47BD-B503-BE1BCB65F7C7 Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=signature.asc Content-Type: application/pgp-signature; name=signature.asc Content-Description: Message signed with OpenPGP using GPGMail -----BEGIN PGP SIGNATURE----- Comment: GPGTools - http://gpgtools.org iD8DBQFTH+eJ5ZPcIHs/zowRAgd5AJ9uSBR0jNitu1oozlz3ibCi6FQ5awCfe/Hy 1Y7etC62aJM3DRnZD9uHkW4= =xdSy -----END PGP SIGNATURE----- --Apple-Mail=_32394B83-8C01-47BD-B503-BE1BCB65F7C7--