[PATCH v2 16/16] perf parse-events: Tidy the setting of the default event name

Ian Rogers
2024-04-16T06:16:53Z

Add comments. Pass ownership of the event name to save on a strdup.

Signed-off-by: Ian Rogers <irogers@google.com>
---
tools/perf/util/parse-events.c | 9 ++++++---
tools/perf/util/parse-events.h | 2 +-
tools/perf/util/parse-events.l | 5 +++++
tools/perf/util/parse-events.y | 10 +++++++---
4 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 1c1b1bcb78e8..0f308b4db2b9 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -1836,18 +1836,21 @@ int parse_events__modifier_event(struct parse_events_state *parse_state, void *l
return parse_events__modifier_list(parse_state, loc, list, mod, /*group=*/false);
}

-int parse_events_name(struct list_head *list, const char *name)
+int parse_events__set_default_name(struct list_head *list, char *name)
{
struct evsel *evsel;
+ bool used_name = false;

__evlist__for_each_entry(list, evsel) {
if (!evsel->name) {
- evsel->name = strdup(name);
+ evsel->name = used_name ? strdup(name) : name;
+ used_name = true;
if (!evsel->name)
return -ENOMEM;
}
}
-
+ if (!used_name)
+ free(name);
return 0;
}

diff --git a/tools/perf/util/parse-events.h b/tools/perf/util/parse-events.h
index 0bb5f0c80a5e..5695308efab9 100644
--- a/tools/perf/util/parse-events.h
+++ b/tools/perf/util/parse-events.h
@@ -207,7 +207,7 @@ int parse_events__modifier_event(struct parse_events_state *parse_state, void *l
struct list_head *list, struct parse_events_modifier mod);
int parse_events__modifier_group(struct parse_events_state *parse_state, void *loc,
struct list_head *list, struct parse_events_modifier mod);
-int parse_events_name(struct list_head *list, const char *name);
+int parse_events__set_default_name(struct list_head *list, char *name);
int parse_events_add_tracepoint(struct list_head *list, int *idx,
const char *sys, const char *event,
struct parse_events_error *error,
diff --git a/tools/perf/util/parse-events.l b/tools/perf/util/parse-events.l
index 4aaf0c53d9b6..08ea2d845dc3 100644
--- a/tools/perf/util/parse-events.l
+++ b/tools/perf/util/parse-events.l
@@ -96,6 +96,11 @@ static int drv_str(yyscan_t scanner, int token)
return token;
}

+/*
+ * Use yyless to return all the characaters to the input. Update the column for
+ * location debugging. If __alloc is non-zero set yylval to the text for the
+ * returned token's value.
+ */
#define REWIND(__alloc) \
do { \
YYSTYPE *__yylval = parse_events_get_lval(yyscanner); \
diff --git a/tools/perf/util/parse-events.y b/tools/perf/util/parse-events.y
index 6f1042272dda..68b3b06c7ff0 100644
--- a/tools/perf/util/parse-events.y
+++ b/tools/perf/util/parse-events.y
@@ -247,10 +247,14 @@ event_name
event_name:
PE_EVENT_NAME event_def
{
- int err;
+ /*
+ * When an event is parsed the text is rewound and the entire text of
+ * the event is set to the str of PE_EVENT_NAME token matched here. If
+ * no name was on an event via a term, set the name to the entire text
+ * taking ownership of the allocation.
+ */
+ int err = parse_events__set_default_name($2, $1);

- err = parse_events_name($2, $1);
- free($1);
if (err) {
free_list_evsel($2);
YYNOMEM;