perf parse-events: Make common term list to strbuf helper

A term list is turned into a string for debug output and for the str
value in the alias.

Add a helper to do this based on existing code, but then fix for
situations like events being identified.

Use strbuf to manage the dynamic memory allocation and remove the 256
byte limit.

Use in various places the string of the term list is required.

Before:

  $ sudo perf stat -vv -e inst_retired.any true
  Using CPUID GenuineIntel-6-8D-1
  intel_pt default config: tsc,mtc,mtc_period=3,psb_period=3,pt,branch
  Attempting to add event pmu 'cpu' with 'inst_retired.any,' that may result in non-fatal errors
  After aliases, add event pmu 'cpu' with 'event,period,' that may result in non-fatal errors
  inst_retired.any -> cpu/inst_retired.any/
  ...

After:

$ sudo perf stat -vv -e inst_retired.any true

  Using CPUID GenuineIntel-6-8D-1
  intel_pt default config: tsc,mtc,mtc_period=3,psb_period=3,pt,branch
  Attempt to add: cpu/inst_retired.any/
  ..after resolving event: cpu/event=0xc0,period=0x1e8483/
  inst_retired.any -> cpu/event=0xc0,period=0x1e8483/
  ...
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
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>
Link: http://lore.kernel.org/lkml/20230830070753.1821629-2-irogers@google.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/parse-events.c

@@ -13,7 +13,7 @@
 #include <subcmd/parse-options.h>
 #include "parse-events.h"
 #include "string2.h"
-#include "strlist.h"
+#include "strbuf.h"
 #include "debug.h"
 #include <api/fs/tracing_path.h>
 #include <perf/cpumap.h>
@@ -1303,19 +1303,6 @@ int parse_events_add_pmu(struct parse_events_state *parse_state,
 
 	pmu = parse_state->fake_pmu ?: perf_pmus__find(name);
 
-	if (verbose > 1 && !(pmu && pmu->selectable)) {
-		fprintf(stderr, "Attempting to add event pmu '%s' with '",
-			name);
-		if (head_config) {
-			struct parse_events_term *term;
-
-			list_for_each_entry(term, head_config, list) {
-				fprintf(stderr, "%s,", term->config);
-			}
-		}
-		fprintf(stderr, "' that may result in non-fatal errors\n");
-	}
-
 	if (!pmu) {
 		char *err_str;
 
@@ -1325,6 +1312,21 @@ int parse_events_add_pmu(struct parse_events_state *parse_state,
 			parse_events_error__handle(err, loc->first_column, err_str, NULL);
 		return -EINVAL;
 	}
+
+	if (verbose > 1) {
+		struct strbuf sb;
+
+		strbuf_init(&sb, /*hint=*/ 0);
+		if (pmu->selectable && !head_config) {
+			strbuf_addf(&sb, "%s//", name);
+		} else {
+			strbuf_addf(&sb, "%s/", name);
+			parse_events_term__to_strbuf(head_config, &sb);
+			strbuf_addch(&sb, '/');
+		}
+		fprintf(stderr, "Attempt to add: %s\n", sb.buf);
+		strbuf_release(&sb);
+	}
 	if (head_config)
 		fix_raw(head_config, pmu);
 
@@ -1349,16 +1351,12 @@ int parse_events_add_pmu(struct parse_events_state *parse_state,
 		return -EINVAL;
 
 	if (verbose > 1) {
-		fprintf(stderr, "After aliases, add event pmu '%s' with '",
-			name);
-		if (head_config) {
-			struct parse_events_term *term;
+		struct strbuf sb;
 
-			list_for_each_entry(term, head_config, list) {
-				fprintf(stderr, "%s,", term->config);
-			}
-		}
-		fprintf(stderr, "' that may result in non-fatal errors\n");
+		strbuf_init(&sb, /*hint=*/ 0);
+		parse_events_term__to_strbuf(head_config, &sb);
+		fprintf(stderr, "..after resolving event: %s/%s/\n", name, sb.buf);
+		strbuf_release(&sb);
 	}
 
 	/*
@@ -1460,7 +1458,12 @@ int parse_events_multi_pmu_add(struct parse_events_state *parse_state,
 		parse_events_copy_term_list(head, &orig_head);
 		if (!parse_events_add_pmu(parse_state, list, pmu->name,
 					  orig_head, auto_merge_stats, loc)) {
-			pr_debug("%s -> %s/%s/\n", str, pmu->name, str);
+			struct strbuf sb;
+
+			strbuf_init(&sb, /*hint=*/ 0);
+			parse_events_term__to_strbuf(orig_head, &sb);
+			pr_debug("%s -> %s/%s/\n", str, pmu->name, sb.buf);
+			strbuf_release(&sb);
 			ok++;
 		}
 		parse_events_terms__delete(orig_head);
@@ -1469,7 +1472,12 @@ int parse_events_multi_pmu_add(struct parse_events_state *parse_state,
 	if (parse_state->fake_pmu) {
 		if (!parse_events_add_pmu(parse_state, list, str, head,
 					  /*auto_merge_stats=*/true, loc)) {
-			pr_debug("%s -> %s/%s/\n", str, "fake_pmu", str);
+			struct strbuf sb;
+
+			strbuf_init(&sb, /*hint=*/ 0);
+			parse_events_term__to_strbuf(head, &sb);
+			pr_debug("%s -> %s/%s/\n", str, "fake_pmu", sb.buf);
+			strbuf_release(&sb);
 			ok++;
 		}
 	}
@@ -2085,7 +2093,7 @@ void parse_events_error__handle(struct parse_events_error *err, int idx,
 		break;
 	default:
 		pr_debug("Multiple errors dropping message: %s (%s)\n",
-			err->str, err->help);
+			err->str, err->help ?: "<no help>");
 		free(err->str);
 		err->str = str;
 		free(err->help);
@@ -2502,6 +2510,47 @@ void parse_events_terms__delete(struct list_head *terms)
 	free(terms);
 }
 
+int parse_events_term__to_strbuf(struct list_head *term_list, struct strbuf *sb)
+{
+	struct parse_events_term *term;
+	bool first = true;
+
+	if (!term_list)
+		return 0;
+
+	list_for_each_entry(term, term_list, list) {
+		int ret;
+
+		if (!first) {
+			ret = strbuf_addch(sb, ',');
+			if (ret < 0)
+				return ret;
+		}
+		first = false;
+
+		if (term->type_val == PARSE_EVENTS__TERM_TYPE_NUM)
+			if (term->type_term == PARSE_EVENTS__TERM_TYPE_USER && term->val.num == 1)
+				ret = strbuf_addf(sb, "%s", term->config);
+			else
+				ret = strbuf_addf(sb, "%s=%#"PRIx64, term->config, term->val.num);
+		else if (term->type_val == PARSE_EVENTS__TERM_TYPE_STR) {
+			if (term->config) {
+				ret = strbuf_addf(sb, "%s=", term->config);
+				if (ret < 0)
+					return ret;
+			} else if (term->type_term < __PARSE_EVENTS__TERM_TYPE_NR) {
+				ret = strbuf_addf(sb, "%s=", config_term_names[term->type_term]);
+				if (ret < 0)
+					return ret;
+			}
+			ret = strbuf_addf(sb, "%s", term->val.str);
+		}
+		if (ret < 0)
+			return ret;
+	}
+	return 0;
+}
+
 void parse_events_evlist_error(struct parse_events_state *parse_state,
 			       int idx, const char *str)
 {

tools/perf/util/parse-events.h

@@ -18,6 +18,7 @@ struct parse_events_error;
 
 struct option;
 struct perf_pmu;
+struct strbuf;
 
 const char *event_type(int type);
 
@@ -152,6 +153,7 @@ int parse_events_term__clone(struct parse_events_term **new,
 void parse_events_term__delete(struct parse_events_term *term);
 void parse_events_terms__delete(struct list_head *terms);
 void parse_events_terms__purge(struct list_head *terms);
+int parse_events_term__to_strbuf(struct list_head *term_list, struct strbuf *sb);
 int parse_events__modifier_event(struct list_head *list, char *str, bool add);
 int parse_events__modifier_group(struct list_head *list, char *event_mod);
 int parse_events_name(struct list_head *list, const char *name);

tools/perf/util/pmu.c

@@ -507,12 +507,11 @@ static int perf_pmu__new_alias(struct perf_pmu *pmu, const char *name,
 				const char *desc, const char *val, FILE *val_fd,
 				const struct pmu_event *pe)
 {
-	struct parse_events_term *term;
 	struct perf_pmu_alias *alias;
 	int ret;
-	char newval[256];
 	const char *long_desc = NULL, *topic = NULL, *unit = NULL, *pmu_name = NULL;
 	bool deprecated = false, perpkg = false;
+	struct strbuf sb;
 
 	if (perf_pmu__find_alias(pmu, name, /*load=*/ false)) {
 		/* Alias was already created/loaded. */
@@ -582,20 +581,10 @@ static int perf_pmu__new_alias(struct perf_pmu *pmu, const char *name,
 	 *
 	 * Rebuild string to make alias->str member comparable.
 	 */
-	ret = 0;
-	list_for_each_entry(term, &alias->terms, list) {
-		if (ret)
-			ret += scnprintf(newval + ret, sizeof(newval) - ret,
-					 ",");
-		if (term->type_val == PARSE_EVENTS__TERM_TYPE_NUM)
-			ret += scnprintf(newval + ret, sizeof(newval) - ret,
-					 "%s=%#x", term->config, term->val.num);
-		else if (term->type_val == PARSE_EVENTS__TERM_TYPE_STR)
-			ret += scnprintf(newval + ret, sizeof(newval) - ret,
-					 "%s=%s", term->config, term->val.str);
-	}
 	zfree(&alias->str);
-	alias->str = strdup(newval);
+	strbuf_init(&sb, /*hint=*/ 0);
+	parse_events_term__to_strbuf(&alias->terms, &sb);
+	alias->str = strbuf_detach(&sb, /*sz=*/ NULL);
 	if (!pe)
 		pmu->sysfs_aliases++;
 	else