C++ instanceKlassHandle::major_version方法代码示例

//.........这里部分代码省略.........
  // Patch the indexes into the constantpool from the array of fields of the evolving
  // class. This is required, because the layout of the new constantpool can be different,
  // so old indexes corresponding to field names and signatures can become invalid.
  patch_indexes_for_fields(k_h, k_h_new);

  // Make new constantpool object (and methodOops via it) point to the original class object
  k_h_new->constants()->set_pool_holder(k_h());

  // Replace methods and constantpool
  k_h->set_methods(_new_methods);
  k_h_new->set_methods(_old_methods);     // To prevent potential GCing of the old methods, 
                                          // and to be able to undo operation easily.

  constantPoolOop old_constants = k_h->constants();
  k_h->set_constants(k_h_new->constants());
  k_h_new->set_constants(old_constants);  // See the previous comment.

  check_methods_and_mark_as_old();
  transfer_old_native_function_registrations();

  // Replace inner_classes
  typeArrayOop old_inner_classes = k_h->inner_classes();
  k_h->set_inner_classes(k_h_new->inner_classes());
  k_h_new->set_inner_classes(old_inner_classes);

  // Initialize the vtable and interface table after
  // methods have been rewritten
  { ResourceMark rm(THREAD);
  k_h->vtable()->initialize_vtable(THREAD); // No exception can happen here
  k_h->itable()->initialize_itable();
  }

  // Copy the "source file name" attribute from new class version
  k_h->set_source_file_name(k_h_new->source_file_name());

  // Copy the "source debug extension" attribute from new class version
  k_h->set_source_debug_extension(k_h_new->source_debug_extension());

  // Use of javac -g could be different in the old and the new
  if (k_h_new->access_flags().has_localvariable_table() !=
      k_h->access_flags().has_localvariable_table()) {

    AccessFlags flags = k_h->access_flags();
    if (k_h_new->access_flags().has_localvariable_table()) {
      flags.set_has_localvariable_table();
    } else {
      flags.clear_has_localvariable_table();
    }
    k_h->set_access_flags(flags);
  }

  // Replace class annotation fields values
  typeArrayOop old_class_annotations = k_h->class_annotations();
  k_h->set_class_annotations(k_h_new->class_annotations());
  k_h_new->set_class_annotations(old_class_annotations);

  // Replace fields annotation fields values
  objArrayOop old_fields_annotations = k_h->fields_annotations();
  k_h->set_fields_annotations(k_h_new->fields_annotations());
  k_h_new->set_fields_annotations(old_fields_annotations);

  // Replace methods annotation fields values
  objArrayOop old_methods_annotations = k_h->methods_annotations();
  k_h->set_methods_annotations(k_h_new->methods_annotations());
  k_h_new->set_methods_annotations(old_methods_annotations);

  // Replace methods parameter annotation fields values
  objArrayOop old_methods_parameter_annotations = k_h->methods_parameter_annotations();
  k_h->set_methods_parameter_annotations(k_h_new->methods_parameter_annotations());
  k_h_new->set_methods_parameter_annotations(old_methods_parameter_annotations);

  // Replace methods default annotation fields values
  objArrayOop old_methods_default_annotations = k_h->methods_default_annotations();
  k_h->set_methods_default_annotations(k_h_new->methods_default_annotations());
  k_h_new->set_methods_default_annotations(old_methods_default_annotations);

  // Replace major version number of class file
  u2 old_major_version = k_h->major_version();
  k_h->set_major_version(k_h_new->major_version());
  k_h_new->set_major_version(old_major_version);

  // Replace CP indexes for class and name+type of enclosing method
  u2 old_class_idx  = k_h->enclosing_method_class_index();
  u2 old_method_idx = k_h->enclosing_method_method_index();
  k_h->set_enclosing_method_indices(k_h_new->enclosing_method_class_index(),
                                    k_h_new->enclosing_method_method_index());
  k_h_new->set_enclosing_method_indices(old_class_idx, old_method_idx);

  // Maintain a linked list of versions of this class. 
  // List is in ascending age order. Current version (k_h) is the head.
  if (k_h->has_previous_version()) {
    k_h_new->set_previous_version(k_h->previous_version());
  }
  k_h->set_previous_version(k_h_new);

  // Adjust constantpool caches and vtables for all classes
  // that reference methods of the evolved class.
  SystemDictionary::classes_do(adjust_cpool_cache_and_vtable);
  k_h->set_rewritten_by_redefine(true);
}