tools lib traceevent: Fix compile warnings in tools/lib/traceevent/event-parse.c

Fix following warnings:

  event-parse.c: In function ‘tep_find_event_by_name’:
  event-parse.c:3521:21: warning: ‘event’ may be used uninitialized in this function [-Wmaybe-uninitialized]
    pevent->last_event = event;
    ~~~~~~~~~~~~~~~~~~~^~~~~~~
    CC       ui/gtk/hists.o
    LINK     plugin_mac80211.so
    CC       nlattr.o
  event-parse.c: In function ‘tep_data_lat_fmt’:
  event-parse.c:5200:4: warning: ‘migrate_disable’ may be used uninitialized in this function [-Wmaybe-uninitialized]
      trace_seq_printf(s, "%d", migrate_disable);
      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  event-parse.c:5207:4: warning: ‘lock_depth’ may be used uninitialized in this function [-Wmaybe-uninitialized]
      trace_seq_printf(s, "%d", lock_depth);
      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    LINK     plugin_sched_switch.so
    LINK     plugin_function.so
    LINK     plugin_xen.so
  event-parse.c: In function ‘tep_event_info’:
  event-parse.c:5047:7: warning: ‘len_arg’ may be used uninitialized in this function [-Wmaybe-uninitialized]
         trace_seq_printf(s, format, len_arg, (char)val);
         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  event-parse.c:4884:6: note: ‘len_arg’ was declared here
    int len_arg;
        ^~~~~~~
  event-parse.c:4338:11: warning: ‘vsize’ may be used uninitialized in this function [-Wmaybe-uninitialized]
       val = tep_read_number(pevent, bptr, vsize);
             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  event-parse.c:4224:6: note: ‘vsize’ was declared here
    int vsize;
        ^~~~~

$ gcc --version
  gcc (Clear Linux OS for Intel Architecture) 8.2.1 20180502

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
Link: http://lkml.kernel.org/r/20181122112937.10582-1-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/lib/traceevent/event-parse.c

@@ -3498,7 +3498,7 @@ struct tep_event_format *
 tep_find_event_by_name(struct tep_handle *pevent,
 		       const char *sys, const char *name)
 {
-	struct tep_event_format *event;
+	struct tep_event_format *event = NULL;
 	int i;
 
 	if (pevent->last_event &&
@@ -4221,7 +4221,7 @@ static struct tep_print_arg *make_bprint_args(char *fmt, void *data, int size, s
 	unsigned long long ip, val;
 	char *ptr;
 	void *bptr;
-	int vsize;
+	int vsize = 0;
 
 	field = pevent->bprint_buf_field;
 	ip_field = pevent->bprint_ip_field;
@@ -4881,7 +4881,7 @@ static void pretty_print(struct trace_seq *s, void *data, int size, struct tep_e
 	char format[32];
 	int show_func;
 	int len_as_arg;
-	int len_arg;
+	int len_arg = 0;
 	int len;
 	int ls;
 
@@ -5146,8 +5146,8 @@ void tep_data_lat_fmt(struct tep_handle *pevent,
 	static int migrate_disable_exists;
 	unsigned int lat_flags;
 	unsigned int pc;
-	int lock_depth;
-	int migrate_disable;
+	int lock_depth = 0;
+	int migrate_disable = 0;
 	int hardirq;
 	int softirq;
 	void *data = record->data;