1 /* 2 * Copyright (c) 1997, 2023, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "classfile/javaClasses.hpp" 27 #include "classfile/moduleEntry.hpp" 28 #include "classfile/symbolTable.hpp" 29 #include "classfile/vmClasses.hpp" 30 #include "classfile/vmSymbols.hpp" 31 #include "gc/shared/collectedHeap.inline.hpp" 32 #include "jvmtifiles/jvmti.h" 33 #include "memory/metaspaceClosure.hpp" 34 #include "memory/resourceArea.hpp" 35 #include "memory/universe.hpp" 36 #include "oops/arrayKlass.hpp" 37 #include "oops/objArrayKlass.hpp" 38 #include "oops/arrayOop.hpp" 39 #include "oops/instanceKlass.hpp" 40 #include "oops/klass.inline.hpp" 41 #include "oops/objArrayOop.hpp" 42 #include "oops/oop.inline.hpp" 43 #include "runtime/handles.inline.hpp" 44 45 int ArrayKlass::static_size(int header_size) { 46 // size of an array klass object 47 assert(header_size <= InstanceKlass::header_size(), "bad header size"); 48 // If this assert fails, see comments in base_create_array_klass. 49 header_size = InstanceKlass::header_size(); 50 int vtable_len = Universe::base_vtable_size(); 51 int size = header_size + vtable_len; 52 return align_metadata_size(size); 53 } 54 55 56 InstanceKlass* ArrayKlass::java_super() const { 57 if (super() == nullptr) return nullptr; // bootstrap case 58 // Array klasses have primary supertypes which are not reported to Java. 59 // Example super chain: String[][] -> Object[][] -> Object[] -> Object 60 return vmClasses::Object_klass(); 61 } 62 63 64 oop ArrayKlass::multi_allocate(int rank, jint* sizes, TRAPS) { 65 ShouldNotReachHere(); 66 return nullptr; 67 } 68 69 // find field according to JVM spec 5.4.3.2, returns the klass in which the field is defined 70 Klass* ArrayKlass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const { 71 // There are no fields in an array klass but look to the super class (Object) 72 assert(super(), "super klass must be present"); 73 return super()->find_field(name, sig, fd); 74 } 75 76 Method* ArrayKlass::uncached_lookup_method(const Symbol* name, 77 const Symbol* signature, 78 OverpassLookupMode overpass_mode, 79 PrivateLookupMode private_mode) const { 80 // There are no methods in an array klass but the super class (Object) has some 81 assert(super(), "super klass must be present"); 82 // Always ignore overpass methods in superclasses, although technically the 83 // super klass of an array, (j.l.Object) should not have 84 // any overpass methods present. 85 return super()->uncached_lookup_method(name, signature, OverpassLookupMode::skip, private_mode); 86 } 87 88 ArrayKlass::ArrayKlass(Symbol* name, KlassKind kind) : 89 Klass(kind), 90 _dimension(1), 91 _higher_dimension(nullptr), 92 _lower_dimension(nullptr) { 93 // Arrays don't add any new methods, so their vtable is the same size as 94 // the vtable of klass Object. 95 set_vtable_length(Universe::base_vtable_size()); 96 set_name(name); 97 set_super(Universe::is_bootstrapping() ? nullptr : vmClasses::Object_klass()); 98 set_layout_helper(Klass::_lh_neutral_value); 99 set_is_cloneable(); // All arrays are considered to be cloneable (See JLS 20.1.5) 100 JFR_ONLY(INIT_ID(this);) 101 } 102 103 Symbol* ArrayKlass::create_element_klass_array_name(Klass* element_klass, bool qdesc, TRAPS) { 104 ResourceMark rm(THREAD); 105 Symbol* name = nullptr; 106 char *name_str = element_klass->name()->as_C_string(); 107 int len = element_klass->name()->utf8_length(); 108 char *new_str = NEW_RESOURCE_ARRAY(char, len + 4); 109 int idx = 0; 110 new_str[idx++] = JVM_SIGNATURE_ARRAY; 111 if (element_klass->is_instance_klass()) { // it could be an array or simple type 112 if (qdesc) { 113 new_str[idx++] = JVM_SIGNATURE_PRIMITIVE_OBJECT; 114 } else { 115 new_str[idx++] = JVM_SIGNATURE_CLASS; 116 } 117 } 118 memcpy(&new_str[idx], name_str, len * sizeof(char)); 119 idx += len; 120 if (element_klass->is_instance_klass()) { 121 new_str[idx++] = JVM_SIGNATURE_ENDCLASS; 122 } 123 new_str[idx++] = '\0'; 124 return SymbolTable::new_symbol(new_str); 125 } 126 127 // Initialization of vtables and mirror object is done separately from base_create_array_klass, 128 // since a GC can happen. At this point all instance variables of the ArrayKlass must be setup. 129 void ArrayKlass::complete_create_array_klass(ArrayKlass* k, Klass* super_klass, ModuleEntry* module_entry, TRAPS) { 130 k->initialize_supers(super_klass, nullptr, CHECK); 131 k->vtable().initialize_vtable(); 132 133 // During bootstrapping, before java.base is defined, the module_entry may not be present yet. 134 // These classes will be put on a fixup list and their module fields will be patched once 135 // java.base is defined. 136 assert((module_entry != nullptr) || ((module_entry == nullptr) && !ModuleEntryTable::javabase_defined()), 137 "module entry not available post " JAVA_BASE_NAME " definition"); 138 oop module = (module_entry != nullptr) ? module_entry->module() : (oop)nullptr; 139 java_lang_Class::create_mirror(k, Handle(THREAD, k->class_loader()), Handle(THREAD, module), Handle(), Handle(), CHECK); 140 } 141 142 GrowableArray<Klass*>* ArrayKlass::compute_secondary_supers(int num_extra_slots, 143 Array<InstanceKlass*>* transitive_interfaces) { 144 // interfaces = { cloneable_klass, serializable_klass }; 145 assert(num_extra_slots == 0, "sanity of primitive array type"); 146 assert(transitive_interfaces == nullptr, "sanity"); 147 // Must share this for correct bootstrapping! 148 set_secondary_supers(Universe::the_array_interfaces_array()); 149 return nullptr; 150 } 151 152 objArrayOop ArrayKlass::allocate_arrayArray(int n, int length, TRAPS) { 153 check_array_allocation_length(length, arrayOopDesc::max_array_length(T_ARRAY), CHECK_NULL); 154 size_t size = objArrayOopDesc::object_size(length); 155 Klass* k = array_klass(n+dimension(), CHECK_NULL); 156 ArrayKlass* ak = ArrayKlass::cast(k); 157 objArrayOop o = (objArrayOop)Universe::heap()->array_allocate(ak, size, length, 158 /* do_zero */ true, CHECK_NULL); 159 // initialization to null not necessary, area already cleared 160 return o; 161 } 162 163 oop ArrayKlass::component_mirror() const { 164 return java_lang_Class::component_mirror(java_mirror()); 165 } 166 167 jint ArrayKlass::compute_modifier_flags() const { 168 return JVM_ACC_ABSTRACT | JVM_ACC_FINAL | JVM_ACC_PUBLIC; 169 } 170 171 // JVMTI support 172 173 jint ArrayKlass::jvmti_class_status() const { 174 return JVMTI_CLASS_STATUS_ARRAY; 175 } 176 177 void ArrayKlass::metaspace_pointers_do(MetaspaceClosure* it) { 178 Klass::metaspace_pointers_do(it); 179 180 ResourceMark rm; 181 log_trace(cds)("Iter(ArrayKlass): %p (%s)", this, external_name()); 182 183 // need to cast away volatile 184 it->push((Klass**)&_higher_dimension); 185 it->push((Klass**)&_lower_dimension); 186 } 187 188 #if INCLUDE_CDS 189 void ArrayKlass::remove_unshareable_info() { 190 Klass::remove_unshareable_info(); 191 if (_higher_dimension != nullptr) { 192 ArrayKlass *ak = ArrayKlass::cast(higher_dimension()); 193 ak->remove_unshareable_info(); 194 } 195 } 196 197 void ArrayKlass::remove_java_mirror() { 198 Klass::remove_java_mirror(); 199 if (_higher_dimension != nullptr) { 200 ArrayKlass *ak = ArrayKlass::cast(higher_dimension()); 201 ak->remove_java_mirror(); 202 } 203 } 204 205 void ArrayKlass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) { 206 assert(loader_data == ClassLoaderData::the_null_class_loader_data(), "array classes belong to null loader"); 207 Klass::restore_unshareable_info(loader_data, protection_domain, CHECK); 208 // Klass recreates the component mirror also 209 210 if (_higher_dimension != nullptr) { 211 ArrayKlass *ak = ArrayKlass::cast(higher_dimension()); 212 ak->restore_unshareable_info(loader_data, protection_domain, CHECK); 213 } 214 } 215 #endif // INCLUDE_CDS 216 217 // Printing 218 219 void ArrayKlass::print_on(outputStream* st) const { 220 assert(is_klass(), "must be klass"); 221 Klass::print_on(st); 222 } 223 224 void ArrayKlass::print_value_on(outputStream* st) const { 225 assert(is_klass(), "must be klass"); 226 for(int index = 0; index < dimension(); index++) { 227 st->print("[]"); 228 } 229 } 230 231 void ArrayKlass::oop_print_on(oop obj, outputStream* st) { 232 assert(obj->is_array(), "must be array"); 233 Klass::oop_print_on(obj, st); 234 st->print_cr(" - length: %d", arrayOop(obj)->length()); 235 } 236 237 238 // Verification 239 240 void ArrayKlass::verify_on(outputStream* st) { 241 Klass::verify_on(st); 242 } 243 244 void ArrayKlass::oop_verify_on(oop obj, outputStream* st) { 245 guarantee(obj->is_array(), "must be array"); 246 arrayOop a = arrayOop(obj); 247 guarantee(a->length() >= 0, "array with negative length?"); 248 }