C++ AccessFlags类代码示例

Klass::Klass() {
  Klass* k = this;

  // Preinitialize supertype information.
  // A later call to initialize_supers() may update these settings:
  set_super(NULL);
  for (juint i = 0; i < Klass::primary_super_limit(); i++) {
    _primary_supers[i] = NULL;
  }
  set_secondary_supers(NULL);
  set_secondary_super_cache(NULL);
  _primary_supers[0] = k;
  set_super_check_offset(in_bytes(primary_supers_offset()));

  set_java_mirror(NULL);
  set_modifier_flags(0);
  set_layout_helper(Klass::_lh_neutral_value);
  set_name(NULL);
  AccessFlags af;
  af.set_flags(0);
  set_access_flags(af);
  set_subklass(NULL);
  set_next_sibling(NULL);
  set_next_link(NULL);
  TRACE_INIT_ID(this);

  set_prototype_header(markOopDesc::prototype());
  set_biased_lock_revocation_count(0);
  set_last_biased_lock_bulk_revocation_time(0);

  // The klass doesn't have any references at this point.
  clear_modified_oops();
  clear_accumulated_modified_oops();
}

// ------------------------------------------------------------------
// ciFieldLayout::fill_in_instance_fields
//
// Set up the instance fields in this ciFieldLayout.
void ciFieldLayout::fill_in_instance_fields(GrowableArray<BasicType>* fieldtypes,
					    GrowableArray<int>* fieldoffsets, 
					    GrowableArray<int>* aflags,
					    int& pos,
					    klassOop current) {
  Klass* k = current->klass_part();
  assert(k->oop_is_instance(), "must be instanceKlass");
  instanceKlass* ik = (instanceKlass*)k;
  klassOop super = k->super();
  if (super) {
    fill_in_instance_fields(fieldtypes, fieldoffsets, aflags, pos, super);
  }

  // Fill in this klass's instance fields.
  typeArrayOop field_list = ik->fields();
  constantPoolOop cpool = ik->constants();
  uint num_fields = field_list->length();

  for (uint i = 0; i < num_fields; i += instanceKlass::next_offset) {
    AccessFlags flags;
    flags.set_flags(field_list->short_at(i + instanceKlass::access_flags_offset));
   
    if (!flags.is_static()) {
      // This is an instance field.  Add it to our list.
      int field_offset = ik->offset_from_fields( i );
      // Add the type to our list.
      symbolOop type_sym = cpool->symbol_at(field_list->short_at(i+
                           instanceKlass::signature_index_offset));
      BasicType field_type; 
      field_type = type2field[FieldType::basic_type(type_sym)];
      fieldtypes->at_put_grow(pos, field_type, T_VOID);
      aflags->at_put_grow(pos, flags.as_int(), 0);
      // The field offset we set here includes the header_size
      fieldoffsets->at_put_grow(pos, field_offset, 0);
      pos++;
    }
  }
}

klassOop Klass::base_create_klass_oop(KlassHandle& klass, int size,
                                      const Klass_vtbl& vtbl, TRAPS) {
  size = align_object_size(size);
  // allocate and initialize vtable
  Klass*   kl = (Klass*) vtbl.allocate_permanent(klass, size, CHECK_NULL);
  klassOop k  = kl->as_klassOop();

  { // Preinitialize supertype information.
    // A later call to initialize_supers() may update these settings:
    kl->set_super(NULL);
    for (juint i = 0; i < Klass::primary_super_limit(); i++) {
      kl->_primary_supers[i] = NULL;
    }
    kl->set_secondary_supers(NULL);
    oop_store_without_check((oop*) &kl->_primary_supers[0], k);
    kl->set_super_check_offset(in_bytes(primary_supers_offset()));
  }

  kl->set_java_mirror(NULL);
  kl->set_modifier_flags(0);
  kl->set_layout_helper(Klass::_lh_neutral_value);
  kl->set_name(NULL);
  AccessFlags af;
  af.set_flags(0);
  kl->set_access_flags(af);
  kl->set_subklass(NULL);
  kl->set_next_sibling(NULL);
  kl->set_alloc_count(0);
  kl->set_alloc_size(0);
  TRACE_SET_KLASS_TRACE_ID(kl, 0);

  kl->set_prototype_header(markOopDesc::prototype());
  kl->set_biased_lock_revocation_count(0);
  kl->set_last_biased_lock_bulk_revocation_time(0);

  return k;
}

methodOop methodKlass::allocate(constMethodHandle xconst,
                                AccessFlags access_flags, TRAPS) {
  int size = methodOopDesc::object_size(access_flags.is_native());
  KlassHandle h_k(THREAD, as_klassOop());
  assert(xconst()->is_parsable(), "possible publication protocol violation");
  methodOop m = (methodOop)CollectedHeap::permanent_obj_allocate(h_k, size, CHECK_NULL);
  assert(!m->is_parsable(), "not expecting parsability yet.");

  No_Safepoint_Verifier no_safepoint;  // until m becomes parsable below
  m->set_constMethod(xconst());
  m->set_access_flags(access_flags);
  m->set_method_size(size);
  m->set_name_index(0);
  m->set_signature_index(0);
#ifdef CC_INTERP
  m->set_result_index(T_VOID);
#endif
  m->set_constants(NULL);
  m->set_max_stack(0);
  m->set_max_locals(0);
  m->set_intrinsic_id(vmIntrinsics::_none);
  m->set_method_data(NULL);
  m->set_interpreter_throwout_count(0);
  m->set_vtable_index(methodOopDesc::garbage_vtable_index);

  // Fix and bury in methodOop
  m->set_interpreter_entry(NULL); // sets i2i entry and from_int
  m->set_highest_tier_compile(CompLevel_none);
  m->set_adapter_entry(NULL);
  m->clear_code(); // from_c/from_i get set to c2i/i2i

  if (access_flags.is_native()) {
    m->clear_native_function();
    m->set_signature_handler(NULL);
  }

  NOT_PRODUCT(m->set_compiled_invocation_count(0);)

methodOop oopFactory::new_method(int byte_code_size, AccessFlags access_flags,
                                 int compressed_line_number_size,
                                 int localvariable_table_length,
                                 int checked_exceptions_length,
                                 bool is_conc_safe,
                                 TRAPS) {
  methodKlass* mk = methodKlass::cast(Universe::methodKlassObj());
  assert(!access_flags.is_native() || byte_code_size == 0,
         "native methods should not contain byte codes");
  constMethodOop cm = new_constMethod(byte_code_size,
                                      compressed_line_number_size,
                                      localvariable_table_length,
                                      checked_exceptions_length,
                                      is_conc_safe, CHECK_NULL);
  constMethodHandle rw(THREAD, cm);
  return mk->allocate(rw, access_flags, CHECK_NULL);
}

 void set_access_flags(AccessFlags flags) const {
   set_access_flags(flags.as_short());
 }

 // Accessors for current field
 AccessFlags access_flags() const {
   AccessFlags flags;
   flags.set_flags(field()->access_flags());
   return flags;
 }

 ciFlags(AccessFlags flags) { _flags = flags.as_int(); }

// Install the redefinition of a class --
// The original instanceKlass object (k_h) always represents the latest 
// version of the respective class. However, during class redefinition we swap
// or replace much of its content with that of the instanceKlass object created
// from the bytes of the redefine (k_h_new). Specifically, k_h points to the new
// constantpool and methods objects, which we take from k_h_new. k_h_new, in turn,
// assumes the role of the previous class version, with the old constantpool and
// methods (taken from k_h) attached to it. k_h links to k_h_new to create a 
// linked list of class versions. 
void VM_RedefineClasses::redefine_single_class(jclass j_clazz, instanceKlassHandle k_h_new, TRAPS) {

  oop mirror = JNIHandles::resolve_non_null(j_clazz);
  klassOop k_oop = java_lang_Class::as_klassOop(mirror);
  instanceKlassHandle k_h = instanceKlassHandle(THREAD, k_oop);

  // Remove all breakpoints in methods of this class
  JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints();
  jvmti_breakpoints.clearall_in_class_at_safepoint(k_oop); 

  // Deoptimize all compiled code that depends on this class
  NOT_CORE(Universe::flush_evol_dependents_on(k_h));

  _old_methods = k_h->methods();
  _new_methods = k_h_new->methods();
  _evolving_koop = k_oop;
  _old_constants = k_h->constants();

  // flush the cached jmethodID fields for _old_methods
  flush_method_jmethod_id_cache();

  // 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);
//.........这里部分代码省略.........

 void set_has_vanilla_constructor() {
   AccessFlags flags = access_flags();
   flags.set_has_vanilla_constructor();
   set_access_flags(flags);
 }

 void set_is_verified() {
   AccessFlags flags = access_flags();
   flags.set_is_verified();
   set_access_flags(flags);
 }

 void set_access_flags(AccessFlags access_flags) {
   int_field_put(access_flags_offset(), access_flags.as_int());
 }

klassOop
instanceKlassKlass::allocate_instance_klass(Symbol* name, int vtable_len, int itable_len,
                                            int static_field_size,
                                            unsigned nonstatic_oop_map_count,
                                            AccessFlags access_flags,
                                            ReferenceType rt,
                                            KlassHandle host_klass, TRAPS) {

  const int nonstatic_oop_map_size =
    instanceKlass::nonstatic_oop_map_size(nonstatic_oop_map_count);
  int size = align_object_offset(vtable_len) + align_object_offset(itable_len);
  if (access_flags.is_interface() || !host_klass.is_null()) {
    size += align_object_offset(nonstatic_oop_map_size);
  } else {
    size += nonstatic_oop_map_size;
  }
  if (access_flags.is_interface()) {
    size += (int)sizeof(klassOop)/HeapWordSize;
  }
  if (!host_klass.is_null()) {
    size += (int)sizeof(klassOop)/HeapWordSize;
  }
  size = instanceKlass::object_size(size);

  // Allocation
  KlassHandle h_this_klass(THREAD, as_klassOop());
  KlassHandle k;
  if (rt == REF_NONE) {
    if (name != vmSymbols::java_lang_Class()) {
      // regular klass
      instanceKlass o;
      k = base_create_klass(h_this_klass, size, o.vtbl_value(), CHECK_NULL);
    } else {
      // Class
      instanceMirrorKlass o;
      k = base_create_klass(h_this_klass, size, o.vtbl_value(), CHECK_NULL);
    }
  } else {
    // reference klass
    instanceRefKlass o;
    k = base_create_klass(h_this_klass, size, o.vtbl_value(), CHECK_NULL);
  }
  {
    No_Safepoint_Verifier no_safepoint; // until k becomes parsable
    instanceKlass* ik = (instanceKlass*) k()->klass_part();
    assert(!k()->is_parsable(), "not expecting parsability yet.");

    // The sizes of these these three variables are used for determining the
    // size of the instanceKlassOop. It is critical that these are set to the right
    // sizes before the first GC, i.e., when we allocate the mirror.
    ik->set_vtable_length(vtable_len);
    ik->set_itable_length(itable_len);
    ik->set_static_field_size(static_field_size);
    ik->set_nonstatic_oop_map_size(nonstatic_oop_map_size);
    ik->set_access_flags(access_flags);
    ik->set_is_anonymous(!host_klass.is_null());
    assert(k()->size() == size, "wrong size for object");

    ik->set_array_klasses(NULL);
    ik->set_methods(NULL);
    ik->set_method_ordering(NULL);
    ik->set_local_interfaces(NULL);
    ik->set_transitive_interfaces(NULL);
    ik->init_implementor();
    ik->set_fields(NULL, 0);
    ik->set_constants(NULL);
    ik->set_class_loader(NULL);
    ik->set_protection_domain(NULL);
    ik->set_signers(NULL);
    ik->set_source_file_name(NULL);
    ik->set_source_debug_extension(NULL, 0);
    ik->set_array_name(NULL);
    ik->set_inner_classes(NULL);
    ik->set_static_oop_field_count(0);
    ik->set_nonstatic_field_size(0);
    ik->set_is_marked_dependent(false);
    ik->set_init_state(instanceKlass::allocated);
    ik->set_init_thread(NULL);
    ik->set_reference_type(rt);
    ik->set_oop_map_cache(NULL);
    ik->set_jni_ids(NULL);
    ik->set_osr_nmethods_head(NULL);
    ik->set_breakpoints(NULL);
    ik->init_previous_versions();
    ik->set_generic_signature(NULL);
    ik->release_set_methods_jmethod_ids(NULL);
    ik->release_set_methods_cached_itable_indices(NULL);
    ik->set_class_annotations(NULL);
    ik->set_fields_annotations(NULL);
    ik->set_methods_annotations(NULL);
    ik->set_methods_parameter_annotations(NULL);
    ik->set_methods_default_annotations(NULL);
    ik->set_jvmti_cached_class_field_map(NULL);
    ik->set_initial_method_idnum(0);
    assert(k()->is_parsable(), "should be parsable here.");

    // initialize the non-header words to zero
    intptr_t* p = (intptr_t*)k();
    for (int index = instanceKlass::header_size(); index < size; index++) {
      p[index] = NULL_WORD;
//.........这里部分代码省略.........

 // update the access_flags for the field in the klass
 void update_klass_field_access_flag() {
   instanceKlass* ik = instanceKlass::cast(field_holder());
   ik->field(index())->set_access_flags(_access_flags.as_short());
 }