[PATCH v1 3/3] perf parse-events: Fix propagation of term's no_value when cloning

[Ian Rogers]

The no_value field in parse_events_term indicates that the val
variable isn't used, the case for an event name. Cloning wasn't
propagating this, making cloned event name terms appearing to have a
constant assinged to them. Working around the bug would check for a
value of 1 assigned to value, but then this meant a user value of 1
couldn't be differentiated causing the value to be lost in debug
printing and perf list.

The change fixes the cloning and updates the "val.num ==/!= 1" tests
to use no_value instead. To better check the no_value is set
appropriately parameter comments are added for constant values. This
found that no_value wasn't set correctly in
parse_events_multi_pmu_add, which matters now that no_value is used to
indicate an event name.

Fixes: 7a6e91644708 ("perf parse-events: Make common term list to strbuf helper")
Fixes: 99e7138eb789 ("perf tools: Fail on using multiple bits long terms without value")
Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
---
 tools/perf/util/parse-events.c | 29 +++++++++++++----------------
 tools/perf/util/parse-events.y |  9 +++++----
 tools/perf/util/pmu.c          |  2 +-
 3 files changed, 19 insertions(+), 21 deletions(-)

diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 51b73207e9f4..68fe2c4ff49f 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -1510,8 +1510,8 @@ int parse_events_multi_pmu_add(struct parse_events_state *parse_state,
 
 	if (parse_events_term__num(&term,
 				   PARSE_EVENTS__TERM_TYPE_USER,
-				   config, 1, false, NULL,
-					NULL) < 0) {
+				   config, /*num=*/1, /*novalue=*/true,
+				   loc, /*loc_val=*/NULL) < 0) {
 		zfree(&config);
 		goto out_err;
 	}
@@ -2482,7 +2482,7 @@ int parse_events_term__num(struct parse_events_term **term,
 		.err_val   = loc_val  ? loc_val->first_column  : 0,
 	};
 
-	return new_term(term, &temp, NULL, num);
+	return new_term(term, &temp, /*str=*/NULL, num);
 }
 
 int parse_events_term__str(struct parse_events_term **term,
@@ -2501,7 +2501,7 @@ int parse_events_term__str(struct parse_events_term **term,
 		.err_val   = loc_val  ? loc_val->first_column  : 0,
 	};
 
-	return new_term(term, &temp, str, 0);
+	return new_term(term, &temp, str, /*num=*/0);
 }
 
 int parse_events_term__term(struct parse_events_term **term,
@@ -2518,26 +2518,21 @@ int parse_events_term__clone(struct parse_events_term **new,
 			     struct parse_events_term *term)
 {
 	char *str;
-	struct parse_events_term temp = {
-		.type_val  = term->type_val,
-		.type_term = term->type_term,
-		.config    = NULL,
-		.err_term  = term->err_term,
-		.err_val   = term->err_val,
-	};
+	struct parse_events_term temp = *term;
 
+	temp.used = false;
 	if (term->config) {
 		temp.config = strdup(term->config);
 		if (!temp.config)
 			return -ENOMEM;
 	}
 	if (term->type_val == PARSE_EVENTS__TERM_TYPE_NUM)
-		return new_term(new, &temp, NULL, term->val.num);
+		return new_term(new, &temp, /*str=*/NULL, term->val.num);
 
 	str = strdup(term->val.str);
 	if (!str)
 		return -ENOMEM;
-	return new_term(new, &temp, str, 0);
+	return new_term(new, &temp, str, /*num=*/0);
 }
 
 void parse_events_term__delete(struct parse_events_term *term)
@@ -2611,20 +2606,22 @@ int parse_events_term__to_strbuf(struct list_head *term_list, struct strbuf *sb)
 		first = false;
 
 		if (term->type_val == PARSE_EVENTS__TERM_TYPE_NUM)
-			if (term->type_term == PARSE_EVENTS__TERM_TYPE_USER && term->val.num == 1)
+			if (term->no_value) {
+				assert(term->type_term == PARSE_EVENTS__TERM_TYPE_USER);
 				ret = strbuf_addf(sb, "%s", term->config);
-			else
+			} 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) {
+			} else if ((unsigned int)term->type_term < __PARSE_EVENTS__TERM_TYPE_NR) {
 				ret = strbuf_addf(sb, "%s=", config_term_name(term->type_term));
 				if (ret < 0)
 					return ret;
 			}
+			assert(!term->no_value);
 			ret = strbuf_addf(sb, "%s", term->val.str);
 		}
 		if (ret < 0)
diff --git a/tools/perf/util/parse-events.y b/tools/perf/util/parse-events.y
index 534daed91c50..4a305df61f74 100644
--- a/tools/perf/util/parse-events.y
+++ b/tools/perf/util/parse-events.y
@@ -712,7 +712,7 @@ name_or_raw '=' PE_VALUE
 {
 	struct parse_events_term *term;
 	int err = parse_events_term__num(&term, PARSE_EVENTS__TERM_TYPE_USER,
-					 $1, $3, false, &@1, &@3);
+					 $1, $3, /*novalue=*/false, &@1, &@3);
 
 	if (err) {
 		free($1);
@@ -739,7 +739,7 @@ PE_LEGACY_CACHE
 {
 	struct parse_events_term *term;
 	int err = parse_events_term__num(&term, PARSE_EVENTS__TERM_TYPE_LEGACY_CACHE,
-					 $1, 1, true, &@1, NULL);
+					 $1, /*num=*/1, /*novalue=*/true, &@1, /*loc_val=*/NULL);
 
 	if (err) {
 		free($1);
@@ -752,7 +752,7 @@ PE_NAME
 {
 	struct parse_events_term *term;
 	int err = parse_events_term__num(&term, PARSE_EVENTS__TERM_TYPE_USER,
-					 $1, 1, true, &@1, NULL);
+					 $1, /*num=*/1, /*novalue=*/true, &@1, /*loc_val=*/NULL);
 
 	if (err) {
 		free($1);
@@ -765,7 +765,8 @@ PE_TERM_HW
 {
 	struct parse_events_term *term;
 	int err = parse_events_term__num(&term, PARSE_EVENTS__TERM_TYPE_HARDWARE,
-					 $1.str, $1.num & 255, false, &@1, NULL);
+					 $1.str, $1.num & 255, /*novalue=*/false,
+					 &@1, /*loc_val=*/NULL);
 
 	if (err) {
 		free($1.str);
diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 152cda84f273..d85602aa4b9f 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -1396,7 +1396,7 @@ static struct perf_pmu_alias *pmu_find_alias(struct perf_pmu *pmu,
 		return NULL;
 
 	if (term->type_val == PARSE_EVENTS__TERM_TYPE_NUM) {
-		if (term->val.num != 1)
+		if (!term->no_value)
 			return NULL;
 		if (pmu_find_format(&pmu->format, term->config))
 			return NULL;
-- 
2.42.0.rc2.253.gd59a3bf2b4-goog