8010124: JVM_GetClassContext: use GrowableArray instead of KlassLink
Summary: replace linked data structure with array (performance)
Reviewed-by: kvn
Contributed-by: christian.thalinger@oracle.com, david.r.chase@oracle.com
--- a/hotspot/src/share/vm/prims/jvm.cpp Tue Jun 11 16:40:31 2013 -0700
+++ b/hotspot/src/share/vm/prims/jvm.cpp Thu Jun 13 15:39:47 2013 -0400
@@ -3230,24 +3230,10 @@
JVM_END
-// Utility object for collecting method holders walking down the stack
-class KlassLink: public ResourceObj {
- public:
- KlassHandle klass;
- KlassLink* next;
-
- KlassLink(KlassHandle k) { klass = k; next = NULL; }
-};
-
-
JVM_ENTRY(jobjectArray, JVM_GetClassContext(JNIEnv *env))
JVMWrapper("JVM_GetClassContext");
ResourceMark rm(THREAD);
JvmtiVMObjectAllocEventCollector oam;
- // Collect linked list of (handles to) method holders
- KlassLink* first = NULL;
- KlassLink* last = NULL;
- int depth = 0;
vframeStream vfst(thread);
if (SystemDictionary::reflect_CallerSensitive_klass() != NULL) {
@@ -3261,32 +3247,23 @@
}
// Collect method holders
+ GrowableArray<KlassHandle>* klass_array = new GrowableArray<KlassHandle>();
for (; !vfst.at_end(); vfst.security_next()) {
Method* m = vfst.method();
// Native frames are not returned
if (!m->is_ignored_by_security_stack_walk() && !m->is_native()) {
Klass* holder = m->method_holder();
assert(holder->is_klass(), "just checking");
- depth++;
- KlassLink* l = new KlassLink(KlassHandle(thread, holder));
- if (first == NULL) {
- first = last = l;
- } else {
- last->next = l;
- last = l;
- }
+ klass_array->append(holder);
}
}
// Create result array of type [Ljava/lang/Class;
- objArrayOop result = oopFactory::new_objArray(SystemDictionary::Class_klass(), depth, CHECK_NULL);
+ objArrayOop result = oopFactory::new_objArray(SystemDictionary::Class_klass(), klass_array->length(), CHECK_NULL);
// Fill in mirrors corresponding to method holders
- int index = 0;
- while (first != NULL) {
- result->obj_at_put(index++, first->klass()->java_mirror());
- first = first->next;
+ for (int i = 0; i < klass_array->length(); i++) {
+ result->obj_at_put(i, klass_array->at(i)->java_mirror());
}
- assert(index == depth, "just checking");
return (jobjectArray) JNIHandles::make_local(env, result);
JVM_END