[PATCH v3 5/9] perf tools: avoid a malloc for array events

Ian Rogers
2019-10-24T19:02:29Z

Use realloc rather than malloc+memcpy to possibly avoid a memory
allocation when appending array elements.

Signed-off-by: Ian Rogers <irogers@google.com>
---
tools/perf/util/parse-events.y | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/tools/perf/util/parse-events.y b/tools/perf/util/parse-events.y
index 26cb65798522..545ab7cefc20 100644
--- a/tools/perf/util/parse-events.y
+++ b/tools/perf/util/parse-events.y
@@ -691,14 +691,12 @@ array_terms ',' array_term
struct parse_events_array new_array;

new_array.nr_ranges = $1.nr_ranges + $3.nr_ranges;
- new_array.ranges = malloc(sizeof(new_array.ranges[0]) *
- new_array.nr_ranges);
+ new_array.ranges = realloc($1.ranges,
+ sizeof(new_array.ranges[0]) *
+ new_array.nr_ranges);
ABORT_ON(!new_array.ranges);
- memcpy(&new_array.ranges[0], $1.ranges,
- $1.nr_ranges * sizeof(new_array.ranges[0]));
memcpy(&new_array.ranges[$1.nr_ranges], $3.ranges,
$3.nr_ranges * sizeof(new_array.ranges[0]));
- free($1.ranges);
free($3.ranges);
$$ = new_array;
}
--
2.23.0.866.gb869b98d4c-goog