perf c2c: Fix 'perf c2c record -e list' to show the default events used

When the event is passed as list, the default events should be listed as
per 'perf mem record -e list'. Previous behavior is:

  $ perf c2c record -e list
  failed: event 'list' not found, use '-e list' to get list of available events

   Usage: perf c2c record [<options>] [<command>]
      or: perf c2c record [<options>] -- <command> [<options>]

      -e, --event <event>   event selector. Use 'perf mem record -e list' to list available events
  $

New behavior:

  $ perf c2c record -e list
  ldlat-loads  : available
  ldlat-stores : available

v3: is a rebase.
v2: addresses review comments by Jiri Olsa.

https://lore.kernel.org/lkml/20191127081844.GH32367@krava/
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20200507220604.3391-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/Documentation/perf-c2c.txt

@@ -40,7 +40,7 @@ RECORD OPTIONS
 --------------
 -e::
 --event=::
-	Select the PMU event. Use 'perf mem record -e list'
+	Select the PMU event. Use 'perf c2c record -e list'
 	to list available events.
 
 -v::

tools/perf/builtin-c2c.c

@@ -2887,8 +2887,15 @@ static int parse_record_events(const struct option *opt,
 {
 	bool *event_set = (bool *) opt->value;
 
+	if (!strcmp(str, "list")) {
+		perf_mem_events__list();
+		exit(0);
+	}
+	if (perf_mem_events__parse(str))
+		exit(-1);
+
 	*event_set = true;
-	return perf_mem_events__parse(str);
+	return 0;
 }
 
 

tools/perf/builtin-mem.c

@@ -38,26 +38,16 @@ static int parse_record_events(const struct option *opt,
 			       const char *str, int unset __maybe_unused)
 {
 	struct perf_mem *mem = *(struct perf_mem **)opt->value;
-	int j;
 
-	if (strcmp(str, "list")) {
-		if (!perf_mem_events__parse(str)) {
-			mem->operation = 0;
-			return 0;
-		}
+	if (!strcmp(str, "list")) {
+		perf_mem_events__list();
+		exit(0);
+	}
+	if (perf_mem_events__parse(str))
 		exit(-1);
-	}
 
-	for (j = 0; j < PERF_MEM_EVENTS__MAX; j++) {
-		struct perf_mem_event *e = &perf_mem_events[j];
-
-		fprintf(stderr, "%-13s%-*s%s\n",
-			e->tag,
-			verbose > 0 ? 25 : 0,
-			verbose > 0 ? perf_mem_events__name(j) : "",
-			e->supported ? ": available" : "");
-	}
-	exit(0);
+	mem->operation = 0;
+	return 0;
 }
 
 static const char * const __usage[] = {

tools/perf/util/mem-events.c

@@ -103,6 +103,21 @@ int perf_mem_events__init(void)
 	return found ? 0 : -ENOENT;
 }
 
+void perf_mem_events__list(void)
+{
+	int j;
+
+	for (j = 0; j < PERF_MEM_EVENTS__MAX; j++) {
+		struct perf_mem_event *e = &perf_mem_events[j];
+
+		fprintf(stderr, "%-13s%-*s%s\n",
+			e->tag,
+			verbose > 0 ? 25 : 0,
+			verbose > 0 ? perf_mem_events__name(j) : "",
+			e->supported ? ": available" : "");
+	}
+}
+
 static const char * const tlb_access[] = {
 	"N/A",
 	"HIT",

tools/perf/util/mem-events.h

@@ -39,6 +39,8 @@ int perf_mem_events__init(void);
 
 char *perf_mem_events__name(int i);
 
+void perf_mem_events__list(void);
+
 struct mem_info;
 int perf_mem__tlb_scnprintf(char *out, size_t sz, struct mem_info *mem_info);
 int perf_mem__lvl_scnprintf(char *out, size_t sz, struct mem_info *mem_info);