8345678: compute_modifiers should not be in create_mirror

Reviewed-by: fparain, dholmes

src/hotspot/share/classfile/classFileParser.cpp

@@ -3747,6 +3747,12 @@ void ClassFileParser::apply_parsed_class_metadata(
   this_klass->set_annotations(_combined_annotations);
   this_klass->set_permitted_subclasses(_permitted_subclasses);
   this_klass->set_record_components(_record_components);
+
+  // Initialize cached modifier_flags to support Class.getModifiers().
+  // This must follow setting inner_class attributes.
+  int computed_modifiers = this_klass->compute_modifier_flags();
+  this_klass->set_modifier_flags(computed_modifiers);
+
   // Delay the setting of _local_interfaces and _transitive_interfaces until after
   // initialize_supers() in fill_instance_klass(). It is because the _local_interfaces could
   // be shared with _transitive_interfaces and _transitive_interfaces may be shared with
@@ -5167,7 +5173,6 @@ void ClassFileParser::fill_instance_klass(InstanceKlass* ik,
   Handle module_handle(THREAD, module_entry->module());
 
   // Allocate mirror and initialize static fields
-  // The create_mirror() call will also call compute_modifiers()
   java_lang_Class::create_mirror(ik,
                                  Handle(THREAD, _loader_data->class_loader()),
                                  module_handle,

src/hotspot/share/classfile/javaClasses.cpp

@@ -1113,12 +1113,6 @@ void java_lang_Class::create_mirror(Klass* k, Handle class_loader,
   assert(k != nullptr, "Use create_basic_type_mirror for primitive types");
   assert(k->java_mirror() == nullptr, "should only assign mirror once");
 
-  // Use this moment of initialization to cache modifier_flags also,
-  // to support Class.getModifiers().  Instance classes recalculate
-  // the cached flags after the class file is parsed, but before the
-  // class is put into the system dictionary.
-  int computed_modifiers = k->compute_modifier_flags();
-  k->set_modifier_flags(computed_modifiers);
   // Class_klass has to be loaded because it is used to allocate
   // the mirror.
   if (vmClasses::Class_klass_loaded()) {

src/hotspot/share/oops/arrayKlass.cpp

@@ -198,10 +198,6 @@ objArrayOop ArrayKlass::allocate_arrayArray(int n, int length, TRAPS) {
   return o;
 }
 
-jint ArrayKlass::compute_modifier_flags() const {
-  return JVM_ACC_ABSTRACT | JVM_ACC_FINAL | JVM_ACC_PUBLIC;
-}
-
 // JVMTI support
 
 jint ArrayKlass::jvmti_class_status() const {

src/hotspot/share/oops/arrayKlass.hpp

@@ -118,10 +118,6 @@ class ArrayKlass: public Klass {
   // Return a handle.
   static void     complete_create_array_klass(ArrayKlass* k, Klass* super_klass, ModuleEntry* module, TRAPS);
 
-
-  // jvm support
-  jint compute_modifier_flags() const;
-
   // JVMTI support
   jint jvmti_class_status() const;
 

src/hotspot/share/oops/objArrayKlass.cpp

@@ -140,6 +140,9 @@ ObjArrayKlass::ObjArrayKlass(int n, Klass* element_klass, Symbol* name) : ArrayK
   set_layout_helper(array_layout_helper(T_OBJECT));
   assert(is_array_klass(), "sanity");
   assert(is_objArray_klass(), "sanity");
+
+  // Compute modifier flags after bottom_klass and element_klass are initialized.
+  set_modifier_flags(compute_modifier_flags());
 }
 
 size_t ObjArrayKlass::oop_size(oop obj) const {
@@ -340,10 +343,8 @@ void ObjArrayKlass::metaspace_pointers_do(MetaspaceClosure* it) {
 
 jint ObjArrayKlass::compute_modifier_flags() const {
   // The modifier for an objectArray is the same as its element
-  if (element_klass() == nullptr) {
-    assert(Universe::is_bootstrapping(), "partial objArray only at startup");
-    return JVM_ACC_ABSTRACT | JVM_ACC_FINAL | JVM_ACC_PUBLIC;
-  }
+  assert (element_klass() != nullptr, "should be initialized");
+
   // Return the flags of the bottom element type.
   jint element_flags = bottom_klass()->compute_modifier_flags();
 

src/hotspot/share/oops/typeArrayKlass.cpp

@@ -75,6 +75,10 @@ TypeArrayKlass* TypeArrayKlass::allocate(ClassLoaderData* loader_data, BasicType
   return new (loader_data, size, THREAD) TypeArrayKlass(type, name);
 }
 
+jint TypeArrayKlass::compute_modifier_flags() const {
+  return JVM_ACC_ABSTRACT | JVM_ACC_FINAL | JVM_ACC_PUBLIC;
+}
+
 TypeArrayKlass::TypeArrayKlass(BasicType type, Symbol* name) : ArrayKlass(name, Kind) {
   set_layout_helper(array_layout_helper(type));
   assert(is_array_klass(), "sanity");
@@ -84,6 +88,9 @@ TypeArrayKlass::TypeArrayKlass(BasicType type, Symbol* name) : ArrayKlass(name,
   assert(size() >= TypeArrayKlass::header_size(), "bad size");
 
   set_class_loader_data(ClassLoaderData::the_null_class_loader_data());
+
+  // Compute modifier flags.
+  set_modifier_flags(compute_modifier_flags());
 }
 
 typeArrayOop TypeArrayKlass::allocate_common(int length, bool do_zero, TRAPS) {

src/hotspot/share/oops/typeArrayKlass.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -73,6 +73,8 @@ class TypeArrayKlass : public ArrayKlass {
   // Copying
   void  copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS);
 
+  jint compute_modifier_flags() const;
+
   // Oop iterators. Since there are no oops in TypeArrayKlasses,
   // these functions only return the size of the object.
 

src/hotspot/share/prims/jvmtiEnv.cpp

@@ -2696,7 +2696,7 @@ JvmtiEnv::GetClassModifiers(oop k_mirror, jint* modifiers_ptr) {
   if (!java_lang_Class::is_primitive(k_mirror)) {
     Klass* k = java_lang_Class::as_Klass(k_mirror);
     NULL_CHECK(k, JVMTI_ERROR_INVALID_CLASS);
-    result = k->compute_modifier_flags();
+    result = k->modifier_flags();
 
     // Reset the deleted  ACC_SUPER bit (deleted in compute_modifier_flags()).
     if (k->is_super()) {