perf parse: Report initial event parsing error

Record the first event parsing error and report. Implementing feedback
from Jiri Olsa:

  https://lkml.org/lkml/2019/10/28/680

An example error is:

  $ tools/perf/perf stat -e c/c/
  WARNING: multiple event parsing errors
  event syntax error: 'c/c/'
                         \___ unknown term

  valid terms: event,filter_rem,filter_opc0,edge,filter_isoc,filter_tid,filter_loc,filter_nc,inv,umask,filter_opc1,tid_en,thresh,filter_all_op,filter_not_nm,filter_state,filter_nm,config,config1,config2,name,period,percore

Initial error:

  event syntax error: 'c/c/'
                      \___ Cannot find PMU `c'. Missing kernel support?
  Run 'perf list' for a list of valid events

   Usage: perf stat [<options>] [<command>]

      -e, --event <event>   event selector. use 'perf list' to list available events

Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Allison Randal <allison@lohutok.net>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Anju T Sudhakar <anju@linux.vnet.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Link: http://lore.kernel.org/lkml/20191116074652.9960-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/tools/perf/util/parse-events.h b/tools/perf/util/parse-events.h
index 5ee8ac93840c..ff367f248fe8 100644
--- a/tools/perf/util/parse-events.h
+++ b/tools/perf/util/parse-events.h
@@ -110,9 +110,13 @@ struct parse_events_term {
 };
 
 struct parse_events_error {
+	int   num_errors;       /* number of errors encountered */
 	int   idx;	/* index in the parsed string */
 	char *str;      /* string to display at the index */
 	char *help;	/* optional help string */
+	int   first_idx;/* as above, but for the first encountered error */
+	char *first_str;
+	char *first_help;
 };
 
 struct parse_events_state {