Add hash map, reduce excessive hashing
Changed the class def index to use a HashMap instead of unordered_map
so that we can use FindWithHash to reduce how often we need to compute
hashes.
Fixed a bug in ClassLinker::UpdateClass where we didn't properly
handle classes with the same descriptor but different class loaders.
Introduced by previous CL.
Before (fb launch):
1.74% art::ComputeModifiedUtf8Hash(char const*)
After:
0.95% art::ComputeModifiedUtf8Hash(char const*)
Bug: 18054905
Bug: 16828525
Change-Id: Iba2ee37c9837289e0ea187800ba4af322225a994
(cherry picked from commit 564ff985184737977aa26c485d0c1a413e530705)
diff --git a/runtime/base/hash_set_test.cc b/runtime/base/hash_set_test.cc
index 885fc06..5f498d9 100644
--- a/runtime/base/hash_set_test.cc
+++ b/runtime/base/hash_set_test.cc
@@ -22,12 +22,11 @@
#include <unordered_set>
#include "common_runtime_test.h"
-#include "utils.h"
+#include "hash_map.h"
namespace art {
-class IsEmptyFnString {
- public:
+struct IsEmptyFnString {
void MakeEmpty(std::string& item) const {
item.clear();
}
@@ -200,4 +199,25 @@
}
}
+struct IsEmptyStringPair {
+ void MakeEmpty(std::pair<std::string, int>& pair) const {
+ pair.first.clear();
+ }
+ bool IsEmpty(const std::pair<std::string, int>& pair) const {
+ return pair.first.empty();
+ }
+};
+
+TEST_F(HashSetTest, TestHashMap) {
+ HashMap<std::string, int, IsEmptyStringPair> hash_map;
+ hash_map.Insert(std::make_pair(std::string("abcd"), 123));
+ hash_map.Insert(std::make_pair(std::string("abcd"), 124));
+ hash_map.Insert(std::make_pair(std::string("bags"), 444));
+ auto it = hash_map.Find(std::string("abcd"));
+ ASSERT_EQ(it->second, 123);
+ hash_map.Erase(it);
+ it = hash_map.Find(std::string("abcd"));
+ ASSERT_EQ(it->second, 124);
+}
+
} // namespace art