perf parse-events: Introduce 'struct parse_events_terms'

parse_events_terms() existed in function names but was passed a
'struct list_head'.

As many parse_events functions take an evsel_config list as well as a
parse_event_term list, and the naming head_terms and head_config is
inconsistent, there's a potential to switch the lists and get errors.

Introduce a 'struct parse_events_terms', that just wraps a list_head, to
avoid this. Add the regular init/exit functions and transition the code
to use them.

Reviewed-by: James Clark <[e-mail]>
Signed-off-by: Ian Rogers <[e-mail]>
Cc: Adrian Hunter <[e-mail]>
Cc: Alexander Shishkin <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Kan Liang <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Rob Herring <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/arch/x86/util/intel-pt.c

···
 					     const char *str,
 					     u64 *config)
 {
-	struct list_head *terms;
+	struct parse_events_terms terms;
 	struct perf_event_attr attr = { .size = 0, };
 	int err;
 
-	terms = malloc(sizeof(struct list_head));
-	if (!terms)
-		return -ENOMEM;
-
-	INIT_LIST_HEAD(terms);
-
-	err = parse_events_terms(terms, str, /*input=*/ NULL);
+	parse_events_terms__init(&terms);
+	err = parse_events_terms(&terms, str, /*input=*/ NULL);
 	if (err)
 		goto out_free;
 
 	attr.config = *config;
-	err = perf_pmu__config_terms(pmu, &attr, terms, /*zero=*/true, /*err=*/NULL);
+	err = perf_pmu__config_terms(pmu, &attr, &terms, /*zero=*/true, /*err=*/NULL);
 	if (err)
 		goto out_free;
 
 	*config = attr.config;
 out_free:
-	parse_events_terms__delete(terms);
+	parse_events_terms__exit(&terms);
 	return err;
 }
 

tools/perf/tests/parse-events.c

···
 	return TEST_OK;
 }
 
-static int test__checkterms_simple(struct list_head *terms)
+static int test__checkterms_simple(struct parse_events_terms *terms)
 {
 	struct parse_events_term *term;
 
 	/* config=10 */
-	term = list_entry(terms->next, struct parse_events_term, list);
+	term = list_entry(terms->terms.next, struct parse_events_term, list);
 	TEST_ASSERT_VAL("wrong type term",
 			term->type_term == PARSE_EVENTS__TERM_TYPE_CONFIG);
 	TEST_ASSERT_VAL("wrong type val",
···
 
 struct terms_test {
 	const char *str;
-	int (*check)(struct list_head *terms);
+	int (*check)(struct parse_events_terms *terms);
 };
 
 static const struct terms_test test__terms[] = {
···
 
 static int test_term(const struct terms_test *t)
 {
-	struct list_head terms;
+	struct parse_events_terms terms;
 	int ret;
 
-	INIT_LIST_HEAD(&terms);
 
+	parse_events_terms__init(&terms);
 	ret = parse_events_terms(&terms, t->str, /*input=*/ NULL);
 	if (ret) {
 		pr_debug("failed to parse terms '%s', err %d\n",
···
 	}
 
 	ret = t->check(&terms);
-	parse_events_terms__purge(&terms);
+	parse_events_terms__exit(&terms);
 
 	return ret;
 }

tools/perf/tests/pmu.c

···
 	return system(buf);
 }
 
-static struct list_head *test_terms_list(void)
+static void add_test_terms(struct parse_events_terms *terms)
 {
-	static LIST_HEAD(terms);
 	unsigned int i;
 
-	for (i = 0; i < ARRAY_SIZE(test_terms); i++)
-		list_add_tail(&test_terms[i].list, &terms);
+	for (i = 0; i < ARRAY_SIZE(test_terms); i++) {
+		struct parse_events_term *clone;
 
-	return &terms;
+		parse_events_term__clone(&clone, &test_terms[i]);
+		list_add_tail(&clone->list, &terms->terms);
+	}
 }
 
 static int test__pmu(struct test_suite *test __maybe_unused, int subtest __maybe_unused)
 {
 	char dir[PATH_MAX];
 	char *format;
-	struct list_head *terms = test_terms_list();
+	struct parse_events_terms terms;
 	struct perf_event_attr attr;
 	struct perf_pmu *pmu;
 	int fd;
 	int ret;
 
+	parse_events_terms__init(&terms);
+	add_test_terms(&terms);
 	pmu = zalloc(sizeof(*pmu));
-	if (!pmu)
+	if (!pmu) {
+		parse_events_terms__exit(&terms);
 		return -ENOMEM;
+	}
 
 	INIT_LIST_HEAD(&pmu->format);
 	INIT_LIST_HEAD(&pmu->aliases);
···
 	format = test_format_dir_get(dir, sizeof(dir));
 	if (!format) {
 		free(pmu);
+		parse_events_terms__exit(&terms);
 		return -EINVAL;
 	}
 
···
 	if (ret)
 		goto out;
 
-	ret = perf_pmu__config_terms(pmu, &attr, terms, /*zero=*/false, /*err=*/NULL);
+	ret = perf_pmu__config_terms(pmu, &attr, &terms, /*zero=*/false, /*err=*/NULL);
 	if (ret)
 		goto out;
 
···
 out:
 	test_format_dir_put(format);
 	perf_pmu__delete(pmu);
+	parse_events_terms__exit(&terms);
 	return ret;
 }
 

tools/perf/util/parse-events.c

···
 #ifdef PARSER_DEBUG
 extern int parse_events_debug;
 #endif
-static int get_config_terms(struct list_head *head_config, struct list_head *head_terms);
-static int parse_events_terms__copy(const struct list_head *src, struct list_head *dest);
+static int get_config_terms(struct parse_events_terms *head_config, struct list_head *head_terms);
+static int parse_events_terms__copy(const struct parse_events_terms *src,
+				    struct parse_events_terms *dest);
 
 struct event_symbol event_symbols_hw[PERF_COUNT_HW_MAX] = {
 	[PERF_COUNT_HW_CPU_CYCLES] = {
···
 	return "unknown";
 }
 
-static char *get_config_str(struct list_head *head_terms, enum parse_events__term_type type_term)
+static char *get_config_str(struct parse_events_terms *head_terms,
+			    enum parse_events__term_type type_term)
 {
 	struct parse_events_term *term;
 
 	if (!head_terms)
 		return NULL;
 
-	list_for_each_entry(term, head_terms, list)
+	list_for_each_entry(term, &head_terms->terms, list)
 		if (term->type_term == type_term)
 			return term->val.str;
 
 	return NULL;
 }
 
-static char *get_config_metric_id(struct list_head *head_terms)
+static char *get_config_metric_id(struct parse_events_terms *head_terms)
 {
 	return get_config_str(head_terms, PARSE_EVENTS__TERM_TYPE_METRIC_ID);
 }
 
-static char *get_config_name(struct list_head *head_terms)
+static char *get_config_name(struct parse_events_terms *head_terms)
 {
 	return get_config_str(head_terms, PARSE_EVENTS__TERM_TYPE_NAME);
 }
···
  * @config_terms: the list of terms that may contain a raw term.
  * @pmu: the PMU to scan for events from.
  */
-static void fix_raw(struct list_head *config_terms, struct perf_pmu *pmu)
+static void fix_raw(struct parse_events_terms *config_terms, struct perf_pmu *pmu)
 {
 	struct parse_events_term *term;
 
-	list_for_each_entry(term, config_terms, list) {
+	list_for_each_entry(term, &config_terms->terms, list) {
 		u64 num;
 
 		if (term->type_term != PARSE_EVENTS__TERM_TYPE_RAW)
···
 			      struct parse_events_term *term,
 			      struct parse_events_error *err);
 static int config_attr(struct perf_event_attr *attr,
-		       struct list_head *head,
+		       struct parse_events_terms *head,
 		       struct parse_events_error *err,
 		       config_term_func_t config_term);
 
···
 
 int parse_events_add_cache(struct list_head *list, int *idx, const char *name,
 			   struct parse_events_state *parse_state,
-			   struct list_head *head_config)
+			   struct parse_events_terms *head_config)
 {
 	struct perf_pmu *pmu = NULL;
 	bool found_supported = false;
···
 static int add_tracepoint(struct list_head *list, int *idx,
 			  const char *sys_name, const char *evt_name,
 			  struct parse_events_error *err,
-			  struct list_head *head_config, void *loc_)
+			  struct parse_events_terms *head_config, void *loc_)
 {
 	YYLTYPE *loc = loc_;
 	struct evsel *evsel = evsel__newtp_idx(sys_name, evt_name, (*idx)++);
···
 static int add_tracepoint_multi_event(struct list_head *list, int *idx,
 				      const char *sys_name, const char *evt_name,
 				      struct parse_events_error *err,
-				      struct list_head *head_config, YYLTYPE *loc)
+				      struct parse_events_terms *head_config, YYLTYPE *loc)
 {
 	char *evt_path;
 	struct dirent *evt_ent;
···
 static int add_tracepoint_event(struct list_head *list, int *idx,
 				const char *sys_name, const char *evt_name,
 				struct parse_events_error *err,
-				struct list_head *head_config, YYLTYPE *loc)
+				struct parse_events_terms *head_config, YYLTYPE *loc)
 {
 	return strpbrk(evt_name, "*?") ?
 		add_tracepoint_multi_event(list, idx, sys_name, evt_name,
···
 static int add_tracepoint_multi_sys(struct list_head *list, int *idx,
 				    const char *sys_name, const char *evt_name,
 				    struct parse_events_error *err,
-				    struct list_head *head_config, YYLTYPE *loc)
+				    struct parse_events_terms *head_config, YYLTYPE *loc)
 {
 	struct dirent *events_ent;
 	DIR *events_dir;
···
 int parse_events_add_breakpoint(struct parse_events_state *parse_state,
 				struct list_head *list,
 				u64 addr, char *type, u64 len,
-				struct list_head *head_config __maybe_unused)
+				struct parse_events_terms *head_config)
 {
 	struct perf_event_attr attr;
 	LIST_HEAD(config_terms);
···
 #endif
 
 static int config_attr(struct perf_event_attr *attr,
-		       struct list_head *head,
+		       struct parse_events_terms *head,
 		       struct parse_events_error *err,
 		       config_term_func_t config_term)
 {
 	struct parse_events_term *term;
 
-	list_for_each_entry(term, head, list)
+	list_for_each_entry(term, &head->terms, list)
 		if (config_term(attr, term, err))
 			return -EINVAL;
 
 	return 0;
 }
 
-static int get_config_terms(struct list_head *head_config, struct list_head *head_terms)
+static int get_config_terms(struct parse_events_terms *head_config, struct list_head *head_terms)
 {
 #define ADD_CONFIG_TERM(__type, __weak)				\
 	struct evsel_config_term *__t;			\
···
 
 	struct parse_events_term *term;
 
-	list_for_each_entry(term, head_config, list) {
+	list_for_each_entry(term, &head_config->terms, list) {
 		switch (term->type_term) {
 		case PARSE_EVENTS__TERM_TYPE_SAMPLE_PERIOD:
 			ADD_CONFIG_TERM_VAL(PERIOD, period, term->val.num, term->weak);
···
  * Add EVSEL__CONFIG_TERM_CFG_CHG where cfg_chg will have a bit set for
  * each bit of attr->config that the user has changed.
  */
-static int get_config_chgs(struct perf_pmu *pmu, struct list_head *head_config,
+static int get_config_chgs(struct perf_pmu *pmu, struct parse_events_terms *head_config,
 			   struct list_head *head_terms)
 {
 	struct parse_events_term *term;
 	u64 bits = 0;
 	int type;
 
-	list_for_each_entry(term, head_config, list) {
+	list_for_each_entry(term, &head_config->terms, list) {
 		switch (term->type_term) {
 		case PARSE_EVENTS__TERM_TYPE_USER:
 			type = perf_pmu__format_type(pmu, term->config);
···
 int parse_events_add_tracepoint(struct list_head *list, int *idx,
 				const char *sys, const char *event,
 				struct parse_events_error *err,
-				struct list_head *head_config, void *loc_)
+				struct parse_events_terms *head_config, void *loc_)
 {
 	YYLTYPE *loc = loc_;
 #ifdef HAVE_LIBTRACEEVENT
···
 static int __parse_events_add_numeric(struct parse_events_state *parse_state,
 				struct list_head *list,
 				struct perf_pmu *pmu, u32 type, u32 extended_type,
-				u64 config, struct list_head *head_config)
+				u64 config, struct parse_events_terms *head_config)
 {
 	struct perf_event_attr attr;
 	LIST_HEAD(config_terms);
···
 int parse_events_add_numeric(struct parse_events_state *parse_state,
 			     struct list_head *list,
 			     u32 type, u64 config,
-			     struct list_head *head_config,
+			     struct parse_events_terms *head_config,
 			     bool wildcard)
 {
 	struct perf_pmu *pmu = NULL;
···
 
 int parse_events_add_pmu(struct parse_events_state *parse_state,
 			 struct list_head *list, const char *name,
-			 const struct list_head *const_head_terms,
+			 const struct parse_events_terms *const_parsed_terms,
 			 bool auto_merge_stats, void *loc_)
 {
 	struct perf_event_attr attr;
···
 	struct parse_events_error *err = parse_state->error;
 	YYLTYPE *loc = loc_;
 	LIST_HEAD(config_terms);
-	LIST_HEAD(head_terms);
+	struct parse_events_terms parsed_terms;
 
 	pmu = parse_state->fake_pmu ?: perf_pmus__find(name);
 
···
 		return -EINVAL;
 	}
 
-	if (const_head_terms) {
-		int ret = parse_events_terms__copy(const_head_terms, &head_terms);
+	parse_events_terms__init(&parsed_terms);
+	if (const_parsed_terms) {
+		int ret = parse_events_terms__copy(const_parsed_terms, &parsed_terms);
 
 		if (ret)
 			return ret;
···
 		struct strbuf sb;
 
 		strbuf_init(&sb, /*hint=*/ 0);
-		if (pmu->selectable && list_empty(&head_terms)) {
+		if (pmu->selectable && list_empty(&parsed_terms.terms)) {
 			strbuf_addf(&sb, "%s//", name);
 		} else {
 			strbuf_addf(&sb, "%s/", name);
-			parse_events_term__to_strbuf(&head_terms, &sb);
+			parse_events_terms__to_strbuf(&parsed_terms, &sb);
 			strbuf_addch(&sb, '/');
 		}
 		fprintf(stderr, "Attempt to add: %s\n", sb.buf);
 		strbuf_release(&sb);
 	}
-	fix_raw(&head_terms, pmu);
+	fix_raw(&parsed_terms, pmu);
 
 	if (pmu->default_config) {
 		memcpy(&attr, pmu->default_config, sizeof(struct perf_event_attr));
···
 	}
 	attr.type = pmu->type;
 
-	if (list_empty(&head_terms)) {
+	if (list_empty(&parsed_terms.terms)) {
 		evsel = __add_event(list, &parse_state->idx, &attr,
 				    /*init_attr=*/true, /*name=*/NULL,
 				    /*metric_id=*/NULL, pmu,
···
 		return evsel ? 0 : -ENOMEM;
 	}
 
-	if (!parse_state->fake_pmu && perf_pmu__check_alias(pmu, &head_terms, &info, err)) {
-		parse_events_terms__purge(&head_terms);
+	if (!parse_state->fake_pmu && perf_pmu__check_alias(pmu, &parsed_terms, &info, err)) {
+		parse_events_terms__exit(&parsed_terms);
 		return -EINVAL;
 	}
 
···
 		struct strbuf sb;
 
 		strbuf_init(&sb, /*hint=*/ 0);
-		parse_events_term__to_strbuf(&head_terms, &sb);
+		parse_events_terms__to_strbuf(&parsed_terms, &sb);
 		fprintf(stderr, "..after resolving event: %s/%s/\n", name, sb.buf);
 		strbuf_release(&sb);
 	}
···
 	 * Configure hardcoded terms first, no need to check
 	 * return value when called with fail == 0 ;)
 	 */
-	if (config_attr(&attr, &head_terms, parse_state->error, config_term_pmu)) {
-		parse_events_terms__purge(&head_terms);
+	if (config_attr(&attr, &parsed_terms, parse_state->error, config_term_pmu)) {
+		parse_events_terms__exit(&parsed_terms);
 		return -EINVAL;
 	}
 
-	if (get_config_terms(&head_terms, &config_terms)) {
-		parse_events_terms__purge(&head_terms);
+	if (get_config_terms(&parsed_terms, &config_terms)) {
+		parse_events_terms__exit(&parsed_terms);
 		return -ENOMEM;
 	}
 
···
 	 * When using default config, record which bits of attr->config were
 	 * changed by the user.
 	 */
-	if (pmu->default_config && get_config_chgs(pmu, &head_terms, &config_terms)) {
-		parse_events_terms__purge(&head_terms);
+	if (pmu->default_config && get_config_chgs(pmu, &parsed_terms, &config_terms)) {
+		parse_events_terms__exit(&parsed_terms);
 		return -ENOMEM;
 	}
 
 	if (!parse_state->fake_pmu &&
-	    perf_pmu__config(pmu, &attr, &head_terms, parse_state->error)) {
+	    perf_pmu__config(pmu, &attr, &parsed_terms, parse_state->error)) {
 		free_config_terms(&config_terms);
-		parse_events_terms__purge(&head_terms);
+		parse_events_terms__exit(&parsed_terms);
 		return -EINVAL;
 	}
 
 	evsel = __add_event(list, &parse_state->idx, &attr, /*init_attr=*/true,
-			    get_config_name(&head_terms),
-			    get_config_metric_id(&head_terms), pmu,
+			    get_config_name(&parsed_terms),
+			    get_config_metric_id(&parsed_terms), pmu,
 			    &config_terms, auto_merge_stats, /*cpu_list=*/NULL);
 	if (!evsel) {
-		parse_events_terms__purge(&head_terms);
+		parse_events_terms__exit(&parsed_terms);
 		return -ENOMEM;
 	}
 
···
 	evsel->percore = config_term_percore(&evsel->config_terms);
 
 	if (parse_state->fake_pmu) {
-		parse_events_terms__purge(&head_terms);
+		parse_events_terms__exit(&parsed_terms);
 		return 0;
 	}
 
-	parse_events_terms__purge(&head_terms);
+	parse_events_terms__exit(&parsed_terms);
 	free((char *)evsel->unit);
 	evsel->unit = strdup(info.unit);
 	evsel->scale = info.scale;
···
 
 int parse_events_multi_pmu_add(struct parse_events_state *parse_state,
 			       const char *event_name,
-			       const struct list_head *const_head_terms,
+			       const struct parse_events_terms *const_parsed_terms,
 			       struct list_head **listp, void *loc_)
 {
 	struct parse_events_term *term;
···
 	YYLTYPE *loc = loc_;
 	int ok = 0;
 	const char *config;
-	LIST_HEAD(head_terms);
+	struct parse_events_terms parsed_terms;
 
 	*listp = NULL;
 
-	if (const_head_terms) {
-		int ret = parse_events_terms__copy(const_head_terms, &head_terms);
+	parse_events_terms__init(&parsed_terms);
+	if (const_parsed_terms) {
+		int ret = parse_events_terms__copy(const_parsed_terms, &parsed_terms);
 
 		if (ret)
 			return ret;
···
 		zfree(&config);
 		goto out_err;
 	}
-	list_add_tail(&term->list, &head_terms);
+	list_add_tail(&term->list, &parsed_terms.terms);
 
 	/* Add it for all PMUs that support the alias */
 	list = malloc(sizeof(struct list_head));
···
 
 		auto_merge_stats = perf_pmu__auto_merge_stats(pmu);
 		if (!parse_events_add_pmu(parse_state, list, pmu->name,
-					  &head_terms, auto_merge_stats, loc)) {
+					  &parsed_terms, auto_merge_stats, loc)) {
 			struct strbuf sb;
 
 			strbuf_init(&sb, /*hint=*/ 0);
-			parse_events_term__to_strbuf(&head_terms, &sb);
+			parse_events_terms__to_strbuf(&parsed_terms, &sb);
 			pr_debug("%s -> %s/%s/\n", event_name, pmu->name, sb.buf);
 			strbuf_release(&sb);
 			ok++;
···
 	}
 
 	if (parse_state->fake_pmu) {
-		if (!parse_events_add_pmu(parse_state, list, event_name, &head_terms,
+		if (!parse_events_add_pmu(parse_state, list, event_name, &parsed_terms,
 					  /*auto_merge_stats=*/true, loc)) {
 			struct strbuf sb;
 
 			strbuf_init(&sb, /*hint=*/ 0);
-			parse_events_term__to_strbuf(&head_terms, &sb);
+			parse_events_terms__to_strbuf(&parsed_terms, &sb);
 			pr_debug("%s -> %s/%s/\n", event_name, "fake_pmu", sb.buf);
 			strbuf_release(&sb);
 			ok++;
···
 	}
 
 out_err:
-	parse_events_terms__purge(&head_terms);
+	parse_events_terms__exit(&parsed_terms);
 	if (ok)
 		*listp = list;
 	else
···
 /*
  * parse event config string, return a list of event terms.
  */
-int parse_events_terms(struct list_head *terms, const char *str, FILE *input)
+int parse_events_terms(struct parse_events_terms *terms, const char *str, FILE *input)
 {
 	struct parse_events_state parse_state = {
 		.terms  = NULL,
···
 	int ret;
 
 	ret = parse_events__scanner(str, input, &parse_state);
+	if (!ret)
+		list_splice(&parse_state.terms->terms, &terms->terms);
 
-	if (!ret) {
-		list_splice(parse_state.terms, terms);
-		zfree(&parse_state.terms);
-		return 0;
-	}
-
-	parse_events_terms__delete(parse_state.terms);
+	zfree(&parse_state.terms);
 	return ret;
 }
 
···
 	free(term);
 }
 
-static int parse_events_terms__copy(const struct list_head *src, struct list_head *dest)
+static int parse_events_terms__copy(const struct parse_events_terms *src,
+				    struct parse_events_terms *dest)
 {
 	struct parse_events_term *term;
 
-	list_for_each_entry (term, src, list) {
+	list_for_each_entry (term, &src->terms, list) {
 		struct parse_events_term *n;
 		int ret;
 
···
 		if (ret)
 			return ret;
 
-		list_add_tail(&n->list, dest);
+		list_add_tail(&n->list, &dest->terms);
 	}
 	return 0;
 }
 
-void parse_events_terms__purge(struct list_head *terms)
+void parse_events_terms__init(struct parse_events_terms *terms)
+{
+	INIT_LIST_HEAD(&terms->terms);
+}
+
+void parse_events_terms__exit(struct parse_events_terms *terms)
 {
 	struct parse_events_term *term, *h;
 
-	list_for_each_entry_safe(term, h, terms, list) {
+	list_for_each_entry_safe(term, h, &terms->terms, list) {
 		list_del_init(&term->list);
 		parse_events_term__delete(term);
 	}
 }
 
-void parse_events_terms__delete(struct list_head *terms)
+void parse_events_terms__delete(struct parse_events_terms *terms)
 {
 	if (!terms)
 		return;
-	parse_events_terms__purge(terms);
+	parse_events_terms__exit(terms);
 	free(terms);
 }
 
-int parse_events_term__to_strbuf(struct list_head *term_list, struct strbuf *sb)
+int parse_events_terms__to_strbuf(const struct parse_events_terms *terms, struct strbuf *sb)
 {
 	struct parse_events_term *term;
 	bool first = true;
 
-	if (!term_list)
+	if (!terms)
 		return 0;
 
-	list_for_each_entry(term, term_list, list) {
+	list_for_each_entry(term, &terms->terms, list) {
 		int ret;
 
 		if (!first) {

tools/perf/util/parse-events.h

···
 
 int parse_event(struct evlist *evlist, const char *str);
 
-int parse_events_terms(struct list_head *terms, const char *str, FILE *input);
 int parse_filter(const struct option *opt, const char *str, int unset);
 int exclude_perf(const struct option *opt, const char *arg, int unset);
 
···
 	char *first_help;
 };
 
+/* A wrapper around a list of terms for the sake of better type safety. */
+struct parse_events_terms {
+	struct list_head terms;
+};
+
 struct parse_events_state {
 	/* The list parsed events are placed on. */
 	struct list_head	   list;
···
 	/* Error information. */
 	struct parse_events_error *error;
 	/* Holds returned terms for term parsing. */
-	struct list_head	  *terms;
+	struct parse_events_terms *terms;
 	/* Start token. */
 	int			   stoken;
 	/* Special fake PMU marker for testing. */
···
 int parse_events_term__clone(struct parse_events_term **new,
 			     struct parse_events_term *term);
 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);
+
+void parse_events_terms__delete(struct parse_events_terms *terms);
+void parse_events_terms__init(struct parse_events_terms *terms);
+void parse_events_terms__exit(struct parse_events_terms *terms);
+int parse_events_terms(struct parse_events_terms *terms, const char *str, FILE *input);
+int parse_events_terms__to_strbuf(const struct parse_events_terms *terms, 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);
 int parse_events_add_tracepoint(struct list_head *list, int *idx,
 				const char *sys, const char *event,
 				struct parse_events_error *error,
-				struct list_head *head_config, void *loc);
+				struct parse_events_terms *head_config, void *loc);
 int parse_events_add_numeric(struct parse_events_state *parse_state,
 			     struct list_head *list,
 			     u32 type, u64 config,
-			     struct list_head *head_config,
+			     struct parse_events_terms *head_config,
 			     bool wildcard);
 int parse_events_add_tool(struct parse_events_state *parse_state,
 			  struct list_head *list,
 			  int tool_event);
 int parse_events_add_cache(struct list_head *list, int *idx, const char *name,
 			   struct parse_events_state *parse_state,
-			   struct list_head *head_config);
+			   struct parse_events_terms *head_config);
 int parse_events__decode_legacy_cache(const char *name, int pmu_type, __u64 *config);
 int parse_events_add_breakpoint(struct parse_events_state *parse_state,
 				struct list_head *list,
 				u64 addr, char *type, u64 len,
-				struct list_head *head_config);
+				struct parse_events_terms *head_config);
 int parse_events_add_pmu(struct parse_events_state *parse_state,
 			 struct list_head *list, const char *name,
-			 const struct list_head *const_head_terms,
+			 const struct parse_events_terms *const_parsed_terms,
 			bool auto_merge_stats, void *loc);
 
 struct evsel *parse_events__add_event(int idx, struct perf_event_attr *attr,
···
 
 int parse_events_multi_pmu_add(struct parse_events_state *parse_state,
 			       const char *event_name,
-			       const struct list_head *head_terms,
+			       const struct parse_events_terms *const_parsed_terms,
 			       struct list_head **listp, void *loc);
 
 void parse_events__set_leader(char *name, struct list_head *list);

tools/perf/util/parse-events.y

···
 	u64 num;
 	enum parse_events__term_type term_type;
 	struct list_head *list_evsel;
-	struct list_head *list_terms;
+	struct parse_events_terms *list_terms;
 	struct parse_events_term *term;
 	struct tracepoint_name {
 		char *sys;
···
 event_config:
 event_config ',' event_term
 {
-	struct list_head *head = $1;
+	struct parse_events_terms *head = $1;
 	struct parse_events_term *term = $3;
 
 	if (!head) {
 		parse_events_term__delete(term);
 		YYABORT;
 	}
-	list_add_tail(&term->list, head);
+	list_add_tail(&term->list, &head->terms);
 	$$ = $1;
 }
 |
 event_term
 {
-	struct list_head *head = malloc(sizeof(*head));
+	struct parse_events_terms *head = malloc(sizeof(*head));
 	struct parse_events_term *term = $1;
 
 	if (!head)
 		YYNOMEM;
-	INIT_LIST_HEAD(head);
-	list_add_tail(&term->list, head);
+	parse_events_terms__init(head);
+	list_add_tail(&term->list, &head->terms);
 	$$ = head;
 }
 

tools/perf/util/pmu.c

···
 	 */
 	char *topic;
 	/** @terms: Owned list of the original parsed parameters. */
-	struct list_head terms;
+	struct parse_events_terms terms;
 	/** @list: List element of struct perf_pmu aliases. */
 	struct list_head list;
 	/**
···
 	zfree(&newalias->long_desc);
 	zfree(&newalias->topic);
 	zfree(&newalias->pmu_name);
-	parse_events_terms__purge(&newalias->terms);
+	parse_events_terms__exit(&newalias->terms);
 	free(newalias);
 }
 
···
 	assign_str(pe->name, "topic", &data->alias->topic, pe->topic);
 	data->alias->per_pkg = pe->perpkg;
 	if (pe->event) {
-		parse_events_terms__purge(&data->alias->terms);
+		parse_events_terms__exit(&data->alias->terms);
 		ret = parse_events_terms(&data->alias->terms, pe->event, /*input=*/NULL);
 	}
 	if (!ret && pe->unit) {
···
 	if (!alias)
 		return -ENOMEM;
 
-	INIT_LIST_HEAD(&alias->terms);
+	parse_events_terms__init(&alias->terms);
 	alias->scale = 1.0;
 	alias->unit[0] = '\0';
 	alias->per_pkg = perpkg;
···
 	return 0;
 }
 
-static int pmu_alias_terms(struct perf_pmu_alias *alias,
-			   struct list_head *terms)
+static int pmu_alias_terms(struct perf_pmu_alias *alias, struct list_head *terms)
 {
 	struct parse_events_term *term, *cloned;
-	LIST_HEAD(list);
-	int ret;
+	struct parse_events_terms clone_terms;
 
-	list_for_each_entry(term, &alias->terms, list) {
-		ret = parse_events_term__clone(&cloned, term);
+	parse_events_terms__init(&clone_terms);
+	list_for_each_entry(term, &alias->terms.terms, list) {
+		int ret = parse_events_term__clone(&cloned, term);
+
 		if (ret) {
-			parse_events_terms__purge(&list);
+			parse_events_terms__exit(&clone_terms);
 			return ret;
 		}
 		/*
···
 		 * which we don't want for implicit terms in aliases.
 		 */
 		cloned->weak = true;
-		list_add_tail(&cloned->list, &list);
+		list_add_tail(&cloned->list, &clone_terms.terms);
 	}
-	list_splice(&list, terms);
+	list_splice_init(&clone_terms.terms, terms);
+	parse_events_terms__exit(&clone_terms);
 	return 0;
 }
 
···
  *   in a config string) later on in the term list.
  */
 static int pmu_resolve_param_term(struct parse_events_term *term,
-				  struct list_head *head_terms,
+				  struct parse_events_terms *head_terms,
 				  __u64 *value)
 {
 	struct parse_events_term *t;
 
-	list_for_each_entry(t, head_terms, list) {
+	list_for_each_entry(t, &head_terms->terms, list) {
 		if (t->type_val == PARSE_EVENTS__TERM_TYPE_NUM &&
 		    t->config && !strcmp(t->config, term->config)) {
 			t->used = true;
···
 static int pmu_config_term(struct perf_pmu *pmu,
 			   struct perf_event_attr *attr,
 			   struct parse_events_term *term,
-			   struct list_head *head_terms,
+			   struct parse_events_terms *head_terms,
 			   bool zero, struct parse_events_error *err)
 {
 	struct perf_pmu_format *format;
···
 
 int perf_pmu__config_terms(struct perf_pmu *pmu,
 			   struct perf_event_attr *attr,
-			   struct list_head *head_terms,
+			   struct parse_events_terms *terms,
 			   bool zero, struct parse_events_error *err)
 {
 	struct parse_events_term *term;
 
-	list_for_each_entry(term, head_terms, list) {
-		if (pmu_config_term(pmu, attr, term, head_terms, zero, err))
+	list_for_each_entry(term, &terms->terms, list) {
+		if (pmu_config_term(pmu, attr, term, terms, zero, err))
 			return -EINVAL;
 	}
 
···
  * 2) pmu format definitions - specified by pmu parameter
  */
 int perf_pmu__config(struct perf_pmu *pmu, struct perf_event_attr *attr,
-		     struct list_head *head_terms,
+		     struct parse_events_terms *head_terms,
 		     struct parse_events_error *err)
 {
 	bool zero = !!pmu->default_config;
···
  * Find alias in the terms list and replace it with the terms
  * defined for the alias
  */
-int perf_pmu__check_alias(struct perf_pmu *pmu, struct list_head *head_terms,
+int perf_pmu__check_alias(struct perf_pmu *pmu, struct parse_events_terms *head_terms,
 			  struct perf_pmu_info *info, struct parse_events_error *err)
 {
 	struct parse_events_term *term, *h;
···
 	info->scale    = 0.0;
 	info->snapshot = false;
 
-	list_for_each_entry_safe(term, h, head_terms, list) {
+	list_for_each_entry_safe(term, h, &head_terms->terms, list) {
 		alias = pmu_find_alias(pmu, term);
 		if (!alias)
 			continue;
···
 		: (int)strlen(pmu->name);
 	int used = snprintf(buf, len, "%.*s/%s", pmu_name_len, pmu->name, alias->name);
 
-	list_for_each_entry(term, &alias->terms, list) {
+	list_for_each_entry(term, &alias->terms.terms, list) {
 		if (term->type_val == PARSE_EVENTS__TERM_TYPE_STR)
 			used += snprintf(buf + used, sub_non_neg(len, used),
 					",%s=%s", term->config,
···
 		info.desc = event->desc;
 		info.long_desc = event->long_desc;
 		info.encoding_desc = buf + buf_used;
-		parse_events_term__to_strbuf(&event->terms, &sb);
+		parse_events_terms__to_strbuf(&event->terms, &sb);
 		buf_used += snprintf(buf + buf_used, sizeof(buf) - buf_used,
 				"%s/%s/", info.pmu_name, sb.buf) + 1;
 		info.topic = event->topic;

tools/perf/util/pmu.h

···
 
 void pmu_add_sys_aliases(struct perf_pmu *pmu);
 int perf_pmu__config(struct perf_pmu *pmu, struct perf_event_attr *attr,
-		     struct list_head *head_terms,
+		     struct parse_events_terms *head_terms,
 		     struct parse_events_error *error);
 int perf_pmu__config_terms(struct perf_pmu *pmu,
 			   struct perf_event_attr *attr,
-			   struct list_head *head_terms,
+			   struct parse_events_terms *terms,
 			   bool zero, struct parse_events_error *error);
 __u64 perf_pmu__format_bits(struct perf_pmu *pmu, const char *name);
 int perf_pmu__format_type(struct perf_pmu *pmu, const char *name);
-int perf_pmu__check_alias(struct perf_pmu *pmu, struct list_head *head_terms,
+int perf_pmu__check_alias(struct perf_pmu *pmu, struct parse_events_terms *head_terms,
 			  struct perf_pmu_info *info, struct parse_events_error *err);
 int perf_pmu__find_event(struct perf_pmu *pmu, const char *event, void *state, pmu_event_callback cb);