8346567: Make Class.getModifiers() non-native

Reviewed-by: alanb, vlivanov, yzheng, dlong

Author: coleenp

src/hotspot/share/c1/c1_Canonicalizer.cpp

@@ -547,22 +547,6 @@ void Canonicalizer::do_Intrinsic      (Intrinsic*       x) {
     }
     break;
   }
-  case vmIntrinsics::_getModifiers: {
-    assert(x->number_of_arguments() == 1, "wrong type");
-
-    // Optimize for Foo.class.getModifier()
-    InstanceConstant* c = x->argument_at(0)->type()->as_InstanceConstant();
-    if (c != nullptr && !c->value()->is_null_object()) {
-      ciType* t = c->value()->java_mirror_type();
-      if (t->is_klass()) {
-        set_constant(t->as_klass()->modifier_flags());
-      } else {
-        assert(t->is_primitive_type(), "should be a primitive type");
-        set_constant(JVM_ACC_ABSTRACT | JVM_ACC_FINAL | JVM_ACC_PUBLIC);
-      }
-    }
-    break;
-  }
   default:
     break;
   }

src/hotspot/share/c1/c1_Compiler.cpp

@@ -156,7 +156,6 @@ bool Compiler::is_intrinsic_supported(vmIntrinsics::ID id) {
   case vmIntrinsics::_getClass:
   case vmIntrinsics::_isInstance:
   case vmIntrinsics::_isPrimitive:
-  case vmIntrinsics::_getModifiers:
   case vmIntrinsics::_currentCarrierThread:
   case vmIntrinsics::_currentThread:
   case vmIntrinsics::_scopedValueCache:

src/hotspot/share/c1/c1_LIRGenerator.cpp

@@ -1297,42 +1297,6 @@ void LIRGenerator::do_isPrimitive(Intrinsic* x) {
   __ cmove(lir_cond_notEqual, LIR_OprFact::intConst(0), LIR_OprFact::intConst(1), result, T_BOOLEAN);
 }
 
-// Example: Foo.class.getModifiers()
-void LIRGenerator::do_getModifiers(Intrinsic* x) {
-  assert(x->number_of_arguments() == 1, "wrong type");
-
-  LIRItem receiver(x->argument_at(0), this);
-  receiver.load_item();
-  LIR_Opr result = rlock_result(x);
-
-  CodeEmitInfo* info = nullptr;
-  if (x->needs_null_check()) {
-    info = state_for(x);
-  }
-
-  // While reading off the universal constant mirror is less efficient than doing
-  // another branch and returning the constant answer, this branchless code runs into
-  // much less risk of confusion for C1 register allocator. The choice of the universe
-  // object here is correct as long as it returns the same modifiers we would expect
-  // from the primitive class itself. See spec for Class.getModifiers that provides
-  // the typed array klasses with similar modifiers as their component types.
-
-  Klass* univ_klass = Universe::byteArrayKlass();
-  assert(univ_klass->modifier_flags() == (JVM_ACC_ABSTRACT | JVM_ACC_FINAL | JVM_ACC_PUBLIC), "Sanity");
-  LIR_Opr prim_klass = LIR_OprFact::metadataConst(univ_klass);
-
-  LIR_Opr recv_klass = new_register(T_METADATA);
-  __ move(new LIR_Address(receiver.result(), java_lang_Class::klass_offset(), T_ADDRESS), recv_klass, info);
-
-  // Check if this is a Java mirror of primitive type, and select the appropriate klass.
-  LIR_Opr klass = new_register(T_METADATA);
-  __ cmp(lir_cond_equal, recv_klass, LIR_OprFact::metadataConst(nullptr));
-  __ cmove(lir_cond_equal, prim_klass, recv_klass, klass, T_ADDRESS);
-
-  // Get the answer.
-  __ move(new LIR_Address(klass, in_bytes(Klass::modifier_flags_offset()), T_CHAR), result);
-}
-
 void LIRGenerator::do_getObjectSize(Intrinsic* x) {
   assert(x->number_of_arguments() == 3, "wrong type");
   LIR_Opr result_reg = rlock_result(x);
@@ -2951,7 +2915,6 @@ void LIRGenerator::do_Intrinsic(Intrinsic* x) {
   case vmIntrinsics::_Object_init:    do_RegisterFinalizer(x); break;
   case vmIntrinsics::_isInstance:     do_isInstance(x);    break;
   case vmIntrinsics::_isPrimitive:    do_isPrimitive(x);   break;
-  case vmIntrinsics::_getModifiers:   do_getModifiers(x);  break;
   case vmIntrinsics::_getClass:       do_getClass(x);      break;
   case vmIntrinsics::_getObjectSize:  do_getObjectSize(x); break;
   case vmIntrinsics::_currentCarrierThread: do_currentCarrierThread(x); break;

src/hotspot/share/c1/c1_LIRGenerator.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2005, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2005, 2025, 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
@@ -255,7 +255,6 @@ class LIRGenerator: public InstructionVisitor, public BlockClosure {
   void do_RegisterFinalizer(Intrinsic* x);
   void do_isInstance(Intrinsic* x);
   void do_isPrimitive(Intrinsic* x);
-  void do_getModifiers(Intrinsic* x);
   void do_getClass(Intrinsic* x);
   void do_getObjectSize(Intrinsic* x);
   void do_currentCarrierThread(Intrinsic* x);

src/hotspot/share/ci/ciKlass.hpp

@@ -119,7 +119,7 @@ class ciKlass : public ciType {
   // Get the instance of java.lang.Class corresponding to this klass.
   ciInstance*            java_mirror();
 
-  // Fetch Klass::modifier_flags.
+  // Fetch modifier flags.
   jint                   modifier_flags();
 
   // Fetch Klass::access_flags.

src/hotspot/share/classfile/classFileParser.cpp

@@ -3747,11 +3747,6 @@ void ClassFileParser::apply_parsed_class_metadata(
   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.
-  u2 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

src/hotspot/share/classfile/javaClasses.cpp

@@ -867,6 +867,7 @@ int java_lang_Class::_source_file_offset;
 int java_lang_Class::_classData_offset;
 int java_lang_Class::_classRedefinedCount_offset;
 int java_lang_Class::_reflectionData_offset;
+int java_lang_Class::_modifiers_offset;
 
 bool java_lang_Class::_offsets_computed = false;
 GrowableArray<Klass*>* java_lang_Class::_fixup_mirror_list = nullptr;
@@ -1060,6 +1061,10 @@ void java_lang_Class::allocate_mirror(Klass* k, bool is_scratch, Handle protecti
   // Setup indirection from mirror->klass
   set_klass(mirror(), k);
 
+  // Set the modifiers flag.
+  int computed_modifiers = k->compute_modifier_flags();
+  set_modifiers(mirror(), computed_modifiers);
+
   InstanceMirrorKlass* mk = InstanceMirrorKlass::cast(mirror->klass());
   assert(oop_size(mirror()) == mk->instance_size(k), "should have been set");
 
@@ -1355,6 +1360,7 @@ oop java_lang_Class::create_basic_type_mirror(const char* basic_type_name, Basic
   InstanceMirrorKlass* mk = InstanceMirrorKlass::cast(vmClasses::Class_klass());
   assert(static_oop_field_count(java_class) == 0, "should have been zeroed by allocation");
 #endif
+  set_modifiers(java_class, JVM_ACC_ABSTRACT | JVM_ACC_FINAL | JVM_ACC_PUBLIC);
   return java_class;
 }
 
@@ -1493,7 +1499,8 @@ oop java_lang_Class::primitive_mirror(BasicType t) {
   macro(_name_offset,                k, "name",                string_signature,       false); \
   macro(_classData_offset,           k, "classData",           object_signature,       false); \
   macro(_reflectionData_offset,      k, "reflectionData",      java_lang_ref_SoftReference_signature, false); \
-  macro(_signers_offset,             k, "signers",             object_array_signature, false);
+  macro(_signers_offset,             k, "signers",             object_array_signature, false); \
+  macro(_modifiers_offset,           k, vmSymbols::modifiers_name(), int_signature,    false);
 
 void java_lang_Class::compute_offsets() {
   if (_offsets_computed) {
@@ -1527,6 +1534,16 @@ void java_lang_Class::set_classRedefinedCount(oop the_class_mirror, int value) {
   the_class_mirror->int_field_put(_classRedefinedCount_offset, value);
 }
 
+int java_lang_Class::modifiers(oop the_class_mirror) {
+  assert(_modifiers_offset != 0, "offsets should have been initialized");
+  return the_class_mirror->int_field(_modifiers_offset);
+}
+
+void java_lang_Class::set_modifiers(oop the_class_mirror, int value) {
+  assert(_modifiers_offset != 0, "offsets should have been initialized");
+  the_class_mirror->int_field_put(_modifiers_offset, value);
+}
+
 
 // Note: JDK1.1 and before had a privateInfo_offset field which was used for the
 //       platform thread structure, and a eetop offset which was used for thread

src/hotspot/share/classfile/javaClasses.hpp

@@ -257,6 +257,7 @@ class java_lang_Class : AllStatic {
   static int _classData_offset;
   static int _classRedefinedCount_offset;
   static int _reflectionData_offset;
+  static int _modifiers_offset;
 
   static bool _offsets_computed;
 
@@ -337,6 +338,9 @@ class java_lang_Class : AllStatic {
   static oop source_file(oop java_class);
   static void set_source_file(oop java_class, oop source_file);
 
+  static int modifiers(oop java_class);
+  static void set_modifiers(oop java_class, int value);
+
   static size_t oop_size(oop java_class);
   static void set_oop_size(HeapWord* java_class, size_t size);
   static int static_oop_field_count(oop java_class);

src/hotspot/share/classfile/vmIntrinsics.cpp

@@ -256,7 +256,6 @@ bool vmIntrinsics::disabled_by_jvm_flags(vmIntrinsics::ID id) {
   switch (id) {
   case vmIntrinsics::_isInstance:
   case vmIntrinsics::_isAssignableFrom:
-  case vmIntrinsics::_getModifiers:
   case vmIntrinsics::_isInterface:
   case vmIntrinsics::_isArray:
   case vmIntrinsics::_isPrimitive:

src/hotspot/share/classfile/vmIntrinsics.hpp

@@ -304,8 +304,6 @@ class methodHandle;
    do_name(     isAssignableFrom_name,                           "isAssignableFrom")                                    \
   do_intrinsic(_isInstance,               java_lang_Class,        isInstance_name, object_boolean_signature,     F_RN)  \
    do_name(     isInstance_name,                                 "isInstance")                                          \
-  do_intrinsic(_getModifiers,             java_lang_Class,        getModifiers_name, void_int_signature,         F_RN)  \
-   do_name(     getModifiers_name,                               "getModifiers")                                        \
   do_intrinsic(_isInterface,              java_lang_Class,        isInterface_name, void_boolean_signature,      F_RN)  \
    do_name(     isInterface_name,                                "isInterface")                                         \
   do_intrinsic(_isArray,                  java_lang_Class,        isArray_name, void_boolean_signature,          F_RN)  \