perf: record TRACE_INFO only if using tracepoints and SAMPLE_RAW

The current perf code implicitly assumes SAMPLE_RAW means tracepoints
are being used, but doesn't check for that.  It happily records the
TRACE_INFO even if SAMPLE_RAW is used without tracepoints, but when the
perf data is read it won't go any further when it finds TRACE_INFO but
no tracepoints, and displays misleading errors.

This adds a check for both in perf-record, and won't record TRACE_INFO
unless both are true.  This at least allows perf report -D to dump raw
events, and avoids triggering a misleading error condition in perf
trace.  It doesn't actually enable the non-tracepoint raw events to be
displayed in perf trace, since perf trace currently only deals with
tracepoint events.

Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1272865861.7932.16.camel@tropicana>
Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/trace-event-info.c b/tools/perf/util/trace-event-info.c
index 30cd9b5..0a1fb9d 100644
--- a/tools/perf/util/trace-event-info.c
+++ b/tools/perf/util/trace-event-info.c
@@ -487,6 +487,11 @@
 	return nr_tracepoints > 0 ? path.next : NULL;
 }
 
+bool have_tracepoints(struct perf_event_attr *pattrs, int nb_events)
+{
+	return get_tracepoints_path(pattrs, nb_events) ? true : false;
+}
+
 int read_tracing_data(int fd, struct perf_event_attr *pattrs, int nb_events)
 {
 	char buf[BUFSIZ];