From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:33267) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1R61VR-00083k-Fy for qemu-devel@nongnu.org; Tue, 20 Sep 2011 10:41:10 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1R61VP-000457-To for qemu-devel@nongnu.org; Tue, 20 Sep 2011 10:41:05 -0400 Received: from mail-gx0-f173.google.com ([209.85.161.173]:42056) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1R61VP-00044s-RH for qemu-devel@nongnu.org; Tue, 20 Sep 2011 10:41:03 -0400 Received: by gxk25 with SMTP id 25so292428gxk.4 for ; Tue, 20 Sep 2011 07:41:03 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20110920143112.GA14814@Krystal> References: <20110916165933.16620.4383.stgit@ginnungagap.bsc.es> <20110916165938.16620.54932.stgit@ginnungagap.bsc.es> <20110920115202.GB23976@stefanha-thinkpad.localdomain> <87ty87z849.fsf@ginnungagap.bsc.es> <20110920143112.GA14814@Krystal> Date: Tue, 20 Sep 2011 15:41:02 +0100 Message-ID: From: Stefan Hajnoczi Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [ltt-dev] [PATCH 2/3] trace: [ust] Do not use 'm' in event argument names (used by ust macros) List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Mathieu Desnoyers Cc: ltt-dev@lists.casi.polymtl.ca, =?ISO-8859-1?Q?Llu=EDs_Vilanova?= , qemu-devel@nongnu.org 2011/9/20 Mathieu Desnoyers : > * Llu=EDs Vilanova (vilanova@ac.upc.edu) wrote: >> Stefan Hajnoczi writes: >> >> > On Fri, Sep 16, 2011 at 06:59:38PM +0200, Llu=EDs Vilanova wrote: >> >> Signed-off-by: Llu=EDs Vilanova >> >> --- >> >> trace-events | =A0 =A04 ++-- >> >> 1 files changed, 2 insertions(+), 2 deletions(-) >> >> >> >> diff --git a/trace-events b/trace-events >> >> index 9d1fbbb..b653d70 100644 >> >> --- a/trace-events >> >> +++ b/trace-events >> >> @@ -418,8 +418,8 @@ milkymist_pfpu_pulse_irq(void) "Pulse IRQ" >> >> # hw/milkymist-softusb.c >> >> milkymist_softusb_memory_read(uint32_t addr, uint32_t value) "addr %0= 8x value %08x" >> >> milkymist_softusb_memory_write(uint32_t addr, uint32_t value) "addr %= 08x value %08x" >> >> -milkymist_softusb_mevt(uint8_t m) "m %d" >> >> -milkymist_softusb_kevt(uint8_t m) "m %d" >> >> +milkymist_softusb_mevt(uint8_t _m) "m %d" >> >> +milkymist_softusb_kevt(uint8_t _m) "m %d" >> >> > The LTTng community has been very responsive in addressing namespace >> > issues with libust. =A0Let's post more details and see if it can be fi= xed >> > in libust. >> >> > Could you please post your gcc and libust versions? >> >> > I have not been able to reproduce the problem on Debian libust-dev >> > 0.15-3. =A0My gcc version is Debian gcc 4.6.1-4. >> >> Yup, I was using libust-dev 0.5 (debian stable). After switching to 0.15= (debian >> testing) other problems arise. >> >> For example, in my box compiling osdep.c yields lots of "variable =91__t= p_cb_data=92 >> set but not used", but using a minimal example does not raise such probl= ems, so >> I'm assuming this is related to some namespace problems related to some = other >> code in qemu's headers. > > If you can find a few minutes to provide: > > 1) a link to the git repository/commit ID you are testing > 2) the exact configuration you use (detailed way to reproduce the > =A0 problem, as a sequence of commands from a pristine repository) > > It will allow me to look into this warning and fix it. AFAICT the only problem with libust is the __tp_cb_data set but not used warning that gcc 4.6 emits, see my test program: #include #include DECLARE_TRACE(ust_milkymist_softusb_mevt, TP_PROTO(uint8_t m), TP_ARGS(m)); int main(int argc, char **argv) { return 0; } You will get an error with gcc 4.6 and libust 0.15: $ gcc -o a -Wall a.c QEMU itself does have one problem with libust 0.15. We do DECLARE_TRACE(name, TP_PROTO(void), TP_ARGS()). This results in a compiler error but we can fix this my changing our tracepoints to use DECLARE_TRACE(name, TP_PROTO(), TP_ARGS()) I think. Perhaps libust's behavior here has changed, it shouldn't be hard to update QEMU's tracetool tracepoint generator though. If you adapt the example program I used above to use TP_PROTO(void), TP_ARGS() then you get this error: a.c: In function =91__trace_ust_milkymist_softusb_mevt=92: a.c:4:1: error: expected declaration specifiers or =91...=92 before =91)=92= token a.c:4:1: error: expected =91)=92 before =91__tp_it_func=92 a.c:4:1: error: expected expression before =91)=92 token a.c:4:1: warning: variable =91__tp_it_func=92 set but not used [-Wunused-but-set-variable] a.c: At top level: a.c:4:1: error: expected declaration specifiers or =91...=92 before =91)=92= token a.c:4:1: error: expected =91;=92, =91,=92 or =91)=92 before =91void=92 a.c:4:1: error: expected declaration specifiers or =91...=92 before =91)=92= token a.c:4:1: error: expected =91;=92, =91,=92 or =91)=92 before =91void=92 a.c: In function =91trace_ust_milkymist_softusb_mevt=92: a.c:4:1: warning: variable =91__tp_cb_data=92 set but not used [-Wunused-but-set-variable] I can't say for sure whether I ever tested old libust versions with void tracepoints. Perhaps we simply never had any and the tracetool generator has always been broken. Or perhaps libust changed its behavior. Stefan