perf list: Simplify symbol event printing

The current code computes an array of symbol names then sorts and prints
them. Use a strlist to create a list of names that is sorted and then
print it.
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Caleb Biggers <caleb.biggers@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Perry Taylor <perry.taylor@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Sandipan Das <sandipan.das@amd.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Weilin Wang <weilin.wang@intel.com>
Cc: Xin Gao <gaoxin@cdjrlc.com>
Cc: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Link: http://lore.kernel.org/lkml/20221114210723.2749751-8-irogers@google.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/print-events.c

@@ -52,14 +52,6 @@ static const struct event_symbol event_symbols_tool[PERF_TOOL_MAX] = {
 	},
 };
 
-static int cmp_string(const void *a, const void *b)
-{
-	const char * const *as = a;
-	const char * const *bs = b;
-
-	return strcmp(*as, *bs);
-}
-
 /*
  * Print the events from <debugfs_mount_point>/tracing/events
  */
@@ -298,77 +290,48 @@ void print_symbol_events(const char *event_glob, unsigned int type,
 			 struct event_symbol *syms, unsigned int max,
 			 bool name_only)
 {
-	unsigned int i, evt_i = 0, evt_num = 0;
-	char name[MAX_NAME_LEN];
-	char **evt_list = NULL;
-	bool evt_num_known = false;
-
-restart:
-	if (evt_num_known) {
-		evt_list = zalloc(sizeof(char *) * evt_num);
-		if (!evt_list)
-			goto out_enomem;
-		syms -= max;
-	}
+	struct strlist *evt_name_list = strlist__new(NULL, NULL);
+	struct str_node *nd;
 
-	for (i = 0; i < max; i++, syms++) {
+	if (!evt_name_list) {
+		pr_debug("Failed to allocate new strlist for symbol events\n");
+		return;
+	}
+	for (unsigned int i = 0; i < max; i++) {
 		/*
 		 * New attr.config still not supported here, the latest
 		 * example was PERF_COUNT_SW_CGROUP_SWITCHES
 		 */
-		if (syms->symbol == NULL)
+		if (syms[i].symbol == NULL)
 			continue;
 
-		if (event_glob != NULL && !(strglobmatch(syms->symbol, event_glob) ||
-		      (syms->alias && strglobmatch(syms->alias, event_glob))))
+		if (event_glob != NULL && !(strglobmatch(syms[i].symbol, event_glob) ||
+		      (syms[i].alias && strglobmatch(syms[i].alias, event_glob))))
 			continue;
 
 		if (!is_event_supported(type, i))
 			continue;
 
-		if (!evt_num_known) {
-			evt_num++;
-			continue;
-		}
-
-		if (!name_only && strlen(syms->alias))
-			snprintf(name, MAX_NAME_LEN, "%s OR %s", syms->symbol, syms->alias);
-		else
-			strlcpy(name, syms->symbol, MAX_NAME_LEN);
+		if (strlen(syms[i].alias)) {
+			char name[MAX_NAME_LEN];
 
-		evt_list[evt_i] = strdup(name);
-		if (evt_list[evt_i] == NULL)
-			goto out_enomem;
-		evt_i++;
+			snprintf(name, MAX_NAME_LEN, "%s OR %s", syms[i].symbol, syms[i].alias);
+			strlist__add(evt_name_list, name);
+		} else
+			strlist__add(evt_name_list, syms[i].symbol);
 	}
 
-	if (!evt_num_known) {
-		evt_num_known = true;
-		goto restart;
-	}
-	qsort(evt_list, evt_num, sizeof(char *), cmp_string);
-	evt_i = 0;
-	while (evt_i < evt_num) {
+	strlist__for_each_entry(nd, evt_name_list) {
 		if (name_only) {
-			printf("%s ", evt_list[evt_i++]);
+			printf("%s ", nd->s);
 			continue;
 		}
-		printf("  %-50s [%s]\n", evt_list[evt_i++], event_type_descriptors[type]);
+		printf("  %-50s [%s]\n", nd->s, event_type_descriptors[type]);
 	}
-	if (evt_num && pager_in_use())
+	if (!strlist__empty(evt_name_list) && pager_in_use())
 		printf("\n");
 
-out_free:
-	evt_num = evt_i;
-	for (evt_i = 0; evt_i < evt_num; evt_i++)
-		zfree(&evt_list[evt_i]);
-	zfree(&evt_list);
-	return;
-
-out_enomem:
-	printf("FATAL: not enough memory to print %s\n", event_type_descriptors[type]);
-	if (evt_list)
-		goto out_free;
+	strlist__delete(evt_name_list);
 }
 
 /*