On 13/06/12 01:25, Mathieu Desnoyers wrote: > * Mathieu Desnoyers ([email protected]) wrote: >> Hi John, >> >> * John Steele Scott ([email protected]) wrote: >>> I want to add lttng-ust tracepoints to a program which builds with >>> "--std=c99 -pedantic". Right now this does not work. >>> >>> Using the demo program as an example, if you enable --std=c99, the first >>> issue looks like: >>> >>> jscott@saaz:~/src/lttng-ust/tests/demo$ ccache gcc -std=c99 -DHAVE_CONFIG_H >>> -I. -I../.. -I../../include/lttng -I../../include -Wall -g -O2 -MT demo.o >>> -MD -MP -MF .deps/demo.Tpo -c -o demo.o demo.c >>> In file included from demo.c:34:0: >>> ust_tests_demo.h: In function ‘__tracepoint_cb_ust_tests_demo___starting’: >>> ust_tests_demo.h:27:23: warning: implicit declaration of function ‘typeof’ >>> [-Wimplicit-function-declaration] >>> ust_tests_demo.h:27:218: error: expected ‘;’ before ‘_________p1’ >>> ust_tests_demo.h:27:395: error: ‘_________p1’ undeclared (first use in this >>> function) >>> ust_tests_demo.h:27:395: note: each undeclared identifier is reported only >>> once for each function it appears in >>> In file included from demo.c:34:0: >>> ust_tests_demo.h: In function ‘__tracepoint_cb_ust_tests_demo___done’: >>> ust_tests_demo.h:35:214: error: expected ‘;’ before ‘_________p1’ >>> ust_tests_demo.h:35:383: error: ‘_________p1’ undeclared (first use in this >>> function) >>> In file included from demo.c:35:0: >>> ust_tests_demo2.h: In function ‘__tracepoint_cb_ust_tests_demo2___loop’: >>> ust_tests_demo2.h:27:299: error: expected ‘;’ before ‘_________p1’ >>> ust_tests_demo2.h:27:470: error: ‘_________p1’ undeclared (first use in >>> this function) >>> In file included from demo.c:36:0: >>> ust_tests_demo3.h: In function ‘__tracepoint_cb_ust_tests_demo3___done’: >>> ust_tests_demo3.h:27:215: error: expected ‘;’ before ‘_________p1’ >>> ust_tests_demo3.h:27:386: error: ‘_________p1’ undeclared (first use in >>> this function) >>> >>> This can be easily resolved by using __typeof__() instead of typeof(). Then >>> I can build with --std=c99. But adding -pedantic still fails: >> I pushed a fix for this: >> >> commit 6423c3134bf07d4a7db56f69f2c79b540a79c4f1 >> Author: Mathieu Desnoyers <[email protected]> >> Date: Mon Jun 11 10:15:25 2012 -0400 >> >> Fix c99 compatibility: use __typeof__ instead of typeof in public headers >> >> Reported-by: John Steele Scott <[email protected]> >> Signed-off-by: Mathieu Desnoyers <[email protected]> >> >> I also had issues with (void) arg parameters with tracepoints, so >> pushed: >> >> commit 4495dd39c05739d0fb2bc463b7c093d2459ce2b6 >> Author: Mathieu Desnoyers <[email protected]> >> Date: Tue Jun 12 11:22:46 2012 -0400 >> >> Fix: support -std=c99 in tracepoint macros >> >> Signed-off-by: Mathieu Desnoyers <[email protected]> >> >> I had also to fix userspace RCU library, with: >> >> >> commit e51500edbd9919cee53bc85cbb4b22cd4786fc42 >> Author: Mathieu Desnoyers <[email protected]> >> Date: Tue Jun 12 11:24:31 2012 -0400 >> >> Fix c99 compatibility: use __asm__ and __volatile__ in public headers >> >> Signed-off-by: Mathieu Desnoyers <[email protected]> >> >> commit bdffa73aa208ad5f1e5b3a3cb6cbf86ac6996559 >> Author: Mathieu Desnoyers <[email protected]> >> Date: Mon Jun 11 10:16:35 2012 -0400 >> >> Fix c99 compatibility: use __typeof__ instead of typeof in public headers >> >> Reported-by: John Steele Scott <[email protected]> >> Signed-off-by: Mathieu Desnoyers <[email protected]> >> >> >>> jscott@saaz:~/src/lttng-ust/tests/demo$ ccache gcc -std=c99 >>> -Dtypeof=__typeof__ -pedantic -DHAVE_CONFIG_H -I. -I../.. >>> -I../../include/lttng -I../../include -Wall -g -O2 -MT demo.o -MD -MP -MF >>> .deps/demo.Tpo -c -o demo.o demo.c >>> In file included from ust_tests_demo.h:25:0, >>> from demo.c:34: >>> ../../include/lttng/tracepoint.h: In function ‘__tracepoints__init’: >>> ../../include/lttng/tracepoint.h:251:4: warning: ISO C forbids conversion >>> of object pointer to function pointer type [-pedantic] >>> ../../include/lttng/tracepoint.h:255:4: warning: ISO C forbids conversion >>> of object pointer to function pointer type [-pedantic] >>> ../../include/lttng/tracepoint.h:260:4: warning: ISO C forbids conversion >>> of object pointer to function pointer type [-pedantic] >>> ../../include/lttng/tracepoint.h:264:4: warning: ISO C forbids conversion >>> of object pointer to function pointer type [-pedantic] >>> ../../include/lttng/tracepoint.h:268:4: warning: ISO C forbids conversion >>> of object pointer to function pointer type [-pedantic] >>> In file included from demo.c:34:0: >>> ust_tests_demo.h: In function ‘__tracepoint_cb_ust_tests_demo___starting’: >>> ust_tests_demo.h:27:161: warning: ISO C forbids braced-groups within >>> expressions [-pedantic] >>> ust_tests_demo.h:27:549: warning: ISO C forbids conversion of object >>> pointer to function pointer type [-pedantic] >>> In file included from demo.c:34:0: >>> ust_tests_demo.h: In function ‘__tracepoint_cb_ust_tests_demo___done’: >>> ust_tests_demo.h:35:161: warning: ISO C forbids braced-groups within >>> expressions [-pedantic] >>> ust_tests_demo.h:35:537: warning: ISO C forbids conversion of object >>> pointer to function pointer type [-pedantic] >>> In file included from demo.c:35:0: >>> ust_tests_demo2.h: In function ‘__tracepoint_cb_ust_tests_demo2___loop’: >>> ust_tests_demo2.h:27:245: warning: ISO C forbids braced-groups within >>> expressions [-pedantic] >>> ust_tests_demo2.h:27:624: warning: ISO C forbids conversion of object >>> pointer to function pointer type [-pedantic] >>> In file included from demo.c:36:0: >>> ust_tests_demo3.h: In function ‘__tracepoint_cb_ust_tests_demo3___done’: >>> ust_tests_demo3.h:27:161: warning: ISO C forbids braced-groups within >>> expressions [-pedantic] >>> ust_tests_demo3.h:27:540: warning: ISO C forbids conversion of object >>> pointer to function pointer type [-pedantic] >> I see these warnings, the only thing that currently fails is due to >> BYTE_ORDER and BIG_ENDIAN not being defined. By adding: >> >> -DBYTE_ORDER=__BYTE_ORDER -DBIG_ENDIAN=__BIG_ENDIAN >> >> my tests/hello program, with a Makefile.am modified to do: >> >> hello_CFLAGS = -Werror=old-style-definition --std=c99 -pedantic >> >> prints many pedantic warnings, and fails with: >> >> ././ust_tests_hello.h:55:1: error: zero or negative size array >> ‘__event_fields___ust_tests_hello___tptest_sighandler’ >> >> which seems to be caused by my event with 0 fields, which try to create >> an array of length 0. >> >> I'll look into this one. > Please try again with lttng-ust master HEAD, userspace-rcu master HEAD, > and let me know if you experience problems compiling your instrumented > application with --std=c99 -pedantic. Please note that the probe object > (e.g. tp.c in the tests/hello program) needs to be compiled with gnu > extensions, so you should not use --std=c99 for this specific object.
Mathieu, Thanks for your reply, sorry it has taken me so long to respond. I can now build this application with userspace tracing. I was actually able to compile the probe object with --std=c99 as well (this time on Centos 6.2, didn't try yet on Ubuntu). Would you expect any problems from this? I only have a single tracepoint in this app, but it does seem to work. The thing I forgot to mention is: okay, I can build now with -pedantic, but I can't build with "-pedantic -Werror". This application builds with "--std=c99 -pedantic -Werror" (among many other flags). I can of course remove -Werror for my tests, but in the longer term I would like to see lttng-ust enabled in our regular build, and disabling -Werror for that is not something we want to do. If I only had to disable it for the trace provider, I could negotiate that, but disabling it for any module which uses tracepoints is undesirable. I haven't yet looked at how difficult it would be do eliminate these pedantic warnings. Do you have a feel for what is involved? Preprocessor tricks warp my mind. :( cheers, John _______________________________________________ lttng-dev mailing list [email protected] http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
