InstanceKlass

InstanceKlass

allocate_instance_klass

InstanceKlass* InstanceKlass::allocate_instance_klass(
                                              ClassLoaderData* loader_data,
                                              int vtable_len,
                                              int itable_len,
                                              int static_field_size,
                                              int nonstatic_oop_map_size,
                                              ReferenceType rt,
                                              AccessFlags access_flags,
                                              Symbol* name,
                                              Klass* super_klass,
                                              bool is_anonymous,
                                              TRAPS) {
    //  获取创建InstanceKlass实例时需要分配的内存空间
  int size = InstanceKlass::size(vtable_len, itable_len, nonstatic_oop_map_size,
                                 access_flags.is_interface(), is_anonymous);

  // Allocation
  InstanceKlass* ik;
  if (rt == REF_NONE) { // 非Reference
    if (name == vmSymbols::java_lang_Class()) { // 通过 todo InstanceMirrorKlass实例表示java.lang.Class类
      ik = new (loader_data, size, THREAD) InstanceMirrorKlass(
        vtable_len, itable_len, static_field_size, nonstatic_oop_map_size, rt,
        access_flags, is_anonymous);
    } else if (name == vmSymbols::java_lang_ClassLoader() ||
          (SystemDictionary::ClassLoader_klass_loaded() &&
          super_klass != NULL &&
          super_klass->is_subtype_of(SystemDictionary::ClassLoader_klass()))) {
      ik = new (loader_data, size, THREAD) InstanceClassLoaderKlass( // 通过InstanceClassLoaderKlass实例表示java.lang.ClassLoader或相关子类
        vtable_len, itable_len, static_field_size, nonstatic_oop_map_size, rt,
        access_flags, is_anonymous);
    } else {
      // normal class
      ik = new (loader_data, size, THREAD) InstanceKlass( // 通过InstanceKlass实例表示普通类
        vtable_len, itable_len, static_field_size, nonstatic_oop_map_size, rt,
        access_flags, is_anonymous);
    }
  } else {
    // reference klass
    ik = new (loader_data, size, THREAD) InstanceRefKlass( // 通过InstanceRefKlass实例表示引用类型
        vtable_len, itable_len, static_field_size, nonstatic_oop_map_size, rt,
        access_flags, is_anonymous);
  }

  // Check for pending exception before adding to the loader data and incrementing
  // class count.  Can get OOM here.
  if (HAS_PENDING_EXCEPTION) {
    return NULL;
  }

  // Add all classes to our internal class loader list here,
  // including classes in the bootstrap (NULL) class loader.
  loader_data->add_class(ik); // add to ClassLoaderData

  Atomic::inc(&_total_instanceKlass_count);
  return ik;
}


// copy method ordering from resource area to Metaspace
void InstanceKlass::copy_method_ordering(intArray* m, TRAPS) {
  if (m != NULL) {
    // allocate a new array and copy contents (memcpy?)
    _method_ordering = MetadataFactory::new_array<int>(class_loader_data(), m->length(), CHECK);
    for (int i = 0; i < m->length(); i++) {
      _method_ordering->at_put(i, m->at(i));
    }
  } else {
    _method_ordering = Universe::the_empty_int_array();
  }
}