6642881: Improve performance of Class.getClassLoader()

Add classLoader to java/lang/Class instance for fast access

Reviewed-by: alanb, lfoltan, rriggs, vlivanov, twisti, jfranck

hotspot/src/share/vm/classfile/classFileParser.cpp

@@ -4139,8 +4139,8 @@ instanceKlassHandle ClassFileParser::parseClassFile(Symbol* name,
     }
 
     // Allocate mirror and initialize static fields
-    java_lang_Class::create_mirror(this_klass, protection_domain, CHECK_(nullHandle));
+    java_lang_Class::create_mirror(this_klass, class_loader, protection_domain,
-
+                                   CHECK_(nullHandle));
 
     // Generate any default methods - default methods are interface methods
     // that have a default implementation.  This is new with Lambda project.

hotspot/src/share/vm/classfile/javaClasses.cpp

@@ -558,7 +558,7 @@ void java_lang_Class::fixup_mirror(KlassHandle k, TRAPS) {
       }
     }
   }
-  create_mirror(k, Handle(NULL), CHECK);
+  create_mirror(k, Handle(NULL), Handle(NULL), CHECK);
 }
 
 void java_lang_Class::initialize_mirror_fields(KlassHandle k,
@@ -578,7 +578,8 @@ void java_lang_Class::initialize_mirror_fields(KlassHandle k,
   InstanceKlass::cast(k())->do_local_static_fields(&initialize_static_field, mirror, CHECK);
 }
 
-void java_lang_Class::create_mirror(KlassHandle k, Handle protection_domain, TRAPS) {
+void java_lang_Class::create_mirror(KlassHandle k, Handle class_loader,
+                                    Handle protection_domain, TRAPS) {
   assert(k->java_mirror() == NULL, "should only assign mirror once");
   // Use this moment of initialization to cache modifier_flags also,
   // to support Class.getModifiers().  Instance classes recalculate
@@ -633,6 +634,9 @@ void java_lang_Class::create_mirror(KlassHandle k, Handle protection_domain, TRA
       }
     }
 
+    // set the classLoader field in the java_lang_Class instance
+    set_class_loader(mirror(), class_loader());
+
     // Setup indirection from klass->mirror last
     // after any exceptions can happen during allocations.
     if (!k.is_null()) {
@@ -694,6 +698,18 @@ void java_lang_Class::set_signers(oop java_class, objArrayOop signers) {
 }
 
 
+void java_lang_Class::set_class_loader(oop java_class, oop loader) {
+  // jdk7 runs Queens in bootstrapping and jdk8-9 has no coordinated pushes yet.
+  if (_class_loader_offset != 0) {
+    java_class->obj_field_put(_class_loader_offset, loader);
+  }
+}
+
+oop java_lang_Class::class_loader(oop java_class) {
+  assert(_class_loader_offset != 0, "must be set");
+  return java_class->obj_field(_class_loader_offset);
+}
+
 oop java_lang_Class::create_basic_type_mirror(const char* basic_type_name, BasicType type, TRAPS) {
   // This should be improved by adding a field at the Java level or by
   // introducing a new VM klass (see comment in ClassFileParser)
@@ -853,6 +869,12 @@ void java_lang_Class::compute_offsets() {
   compute_optional_offset(classRedefinedCount_offset,
                           klass_oop, vmSymbols::classRedefinedCount_name(), vmSymbols::int_signature());
 
+  // Needs to be optional because the old build runs Queens during bootstrapping
+  // and jdk8-9 doesn't have coordinated pushes yet.
+  compute_optional_offset(_class_loader_offset,
+                 klass_oop, vmSymbols::classLoader_name(),
+                 vmSymbols::classloader_signature());
+
   CLASS_INJECTED_FIELDS(INJECTED_FIELD_COMPUTE_OFFSET);
 }
 
@@ -3073,6 +3095,7 @@ int java_lang_Class::_klass_offset;
 int java_lang_Class::_array_klass_offset;
 int java_lang_Class::_oop_size_offset;
 int java_lang_Class::_static_oop_field_count_offset;
+int java_lang_Class::_class_loader_offset;
 int java_lang_Class::_protection_domain_offset;
 int java_lang_Class::_init_lock_offset;
 int java_lang_Class::_signers_offset;

hotspot/src/share/vm/classfile/javaClasses.hpp

@@ -240,19 +240,23 @@ class java_lang_Class : AllStatic {
   static int _protection_domain_offset;
   static int _init_lock_offset;
   static int _signers_offset;
+  static int _class_loader_offset;
 
   static bool offsets_computed;
   static int classRedefinedCount_offset;
+
   static GrowableArray<Klass*>* _fixup_mirror_list;
 
   static void set_init_lock(oop java_class, oop init_lock);
   static void set_protection_domain(oop java_class, oop protection_domain);
+  static void set_class_loader(oop java_class, oop class_loader);
   static void initialize_mirror_fields(KlassHandle k, Handle mirror, Handle protection_domain, TRAPS);
  public:
   static void compute_offsets();
 
   // Instance creation
-  static void create_mirror(KlassHandle k, Handle protection_domain, TRAPS);
+  static void create_mirror(KlassHandle k, Handle class_loader,
+                            Handle protection_domain, TRAPS);
   static void fixup_mirror(KlassHandle k, TRAPS);
   static oop  create_basic_type_mirror(const char* basic_type_name, BasicType type, TRAPS);
   // Conversion
@@ -290,6 +294,8 @@ class java_lang_Class : AllStatic {
   static objArrayOop  signers(oop java_class);
   static void set_signers(oop java_class, objArrayOop signers);
 
+  static oop class_loader(oop java_class);
+
   static int oop_size(oop java_class);
   static void set_oop_size(oop java_class, int size);
   static int static_oop_field_count(oop java_class);

hotspot/src/share/vm/classfile/vmSymbols.hpp

@@ -572,6 +572,7 @@
   template(serializePropertiesToByteArray_signature,   "()[B")                                                    \
   template(serializeAgentPropertiesToByteArray_name,   "serializeAgentPropertiesToByteArray")                     \
   template(classRedefinedCount_name,                   "classRedefinedCount")                                     \
+  template(classLoader_name,                           "classLoader")                                             \
                                                                                                                   \
   /* trace signatures */                                                                                          \
   TRACE_TEMPLATES(template)                                                                                       \

hotspot/src/share/vm/oops/arrayKlass.cpp

@@ -93,7 +93,7 @@ void ArrayKlass::complete_create_array_klass(ArrayKlass* k, KlassHandle super_kl
   ResourceMark rm(THREAD);
   k->initialize_supers(super_klass(), CHECK);
   k->vtable()->initialize_vtable(false, CHECK);
-  java_lang_Class::create_mirror(k, Handle(NULL), CHECK);
+  java_lang_Class::create_mirror(k, Handle(NULL), Handle(NULL), CHECK);
 }
 
 GrowableArray<Klass*>* ArrayKlass::compute_secondary_supers(int num_extra_slots) {

hotspot/src/share/vm/oops/klass.cpp

@@ -508,7 +508,7 @@ void Klass::restore_unshareable_info(TRAPS) {
   // Only recreate it if not present.  A previous attempt to restore may have
   // gotten an OOM later but keep the mirror if it was created.
   if (java_mirror() == NULL) {
-    java_lang_Class::create_mirror(this, Handle(NULL), CHECK);
+    java_lang_Class::create_mirror(this, Handle(NULL), Handle(NULL), CHECK);
   }
 }
 

hotspot/src/share/vm/prims/unsafe.cpp

@@ -891,6 +891,14 @@ UNSAFE_ENTRY(jclass, Unsafe_DefineClass(JNIEnv *env, jobject unsafe, jstring nam
   }
 UNSAFE_END
 
+static jobject get_class_loader(JNIEnv* env, jclass cls) {
+  if (java_lang_Class::is_primitive(JNIHandles::resolve_non_null(cls))) {
+    return NULL;
+  }
+  Klass* k = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(cls));
+  oop loader = k->class_loader();
+  return JNIHandles::make_local(env, loader);
+}
 
 UNSAFE_ENTRY(jclass, Unsafe_DefineClass0(JNIEnv *env, jobject unsafe, jstring name, jbyteArray data, int offset, int length))
   UnsafeWrapper("Unsafe_DefineClass");
@@ -899,7 +907,7 @@ UNSAFE_ENTRY(jclass, Unsafe_DefineClass0(JNIEnv *env, jobject unsafe, jstring na
 
     int depthFromDefineClass0 = 1;
     jclass  caller = JVM_GetCallerClass(env, depthFromDefineClass0);
-    jobject loader = (caller == NULL) ? NULL : JVM_GetClassLoader(env, caller);
+    jobject loader = (caller == NULL) ? NULL : get_class_loader(env, caller);
     jobject pd     = (caller == NULL) ? NULL : JVM_GetProtectionDomain(env, caller);
 
     return Unsafe_DefineClass_impl(env, name, data, offset, length, loader, pd);