1 /* 2 * Copyright (c) 1997, 2025, 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 "cds/cdsConfig.hpp" 26 #include "cds/metaspaceShared.hpp" 27 #include "classfile/javaClasses.hpp" 28 #include "classfile/moduleEntry.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.inline.hpp" 37 #include "oops/arrayOop.hpp" 38 #include "oops/instanceKlass.hpp" 39 #include "oops/klass.inline.hpp" 40 #include "oops/objArrayOop.hpp" 41 #include "oops/oop.inline.hpp" 42 #include "runtime/handles.inline.hpp" 43 44 void* ArrayKlass::operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw() { 45 return Metaspace::allocate(loader_data, word_size, MetaspaceObj::ClassType, true, THREAD); 46 } 47 48 ArrayKlass::ArrayKlass() { 49 assert(CDSConfig::is_dumping_static_archive() || CDSConfig::is_using_archive(), "only for CDS"); 50 } 51 52 int ArrayKlass::static_size(int header_size) { 53 // size of an array klass object 54 assert(header_size <= InstanceKlass::header_size(), "bad header size"); 55 // If this assert fails, see comments in base_create_array_klass. 56 header_size = InstanceKlass::header_size(); 57 int vtable_len = Universe::base_vtable_size(); 58 int size = header_size + vtable_len; 59 return align_metadata_size(size); 60 } 61 62 63 InstanceKlass* ArrayKlass::java_super() const { 64 if (super() == nullptr) return nullptr; // bootstrap case 65 // Array klasses have primary supertypes which are not reported to Java. 66 // Example super chain: String[][] -> Object[][] -> Object[] -> Object 67 return vmClasses::Object_klass(); 68 } 69 70 71 oop ArrayKlass::multi_allocate(int rank, jint* sizes, TRAPS) { 72 ShouldNotReachHere(); 73 return nullptr; 74 } 75 76 // find field according to JVM spec 5.4.3.2, returns the klass in which the field is defined 77 Klass* ArrayKlass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const { 78 // There are no fields in an array klass but look to the super class (Object) 79 assert(super(), "super klass must be present"); 80 return super()->find_field(name, sig, fd); 81 } 82 83 Method* ArrayKlass::uncached_lookup_method(const Symbol* name, 84 const Symbol* signature, 85 OverpassLookupMode overpass_mode, 86 PrivateLookupMode private_mode) const { 87 // There are no methods in an array klass but the super class (Object) has some 88 assert(super(), "super klass must be present"); 89 // Always ignore overpass methods in superclasses, although technically the 90 // super klass of an array, (j.l.Object) should not have 91 // any overpass methods present. 92 return super()->uncached_lookup_method(name, signature, OverpassLookupMode::skip, private_mode); 93 } 94 95 ArrayKlass::ArrayKlass(Symbol* name, KlassKind kind) : 96 Klass(kind), 97 _dimension(1), 98 _higher_dimension(nullptr), 99 _lower_dimension(nullptr) { 100 // Arrays don't add any new methods, so their vtable is the same size as 101 // the vtable of klass Object. 102 set_vtable_length(Universe::base_vtable_size()); 103 set_name(name); 104 set_super(Universe::is_bootstrapping() ? nullptr : vmClasses::Object_klass()); 105 set_layout_helper(Klass::_lh_neutral_value); 106 set_is_cloneable(); // All arrays are considered to be cloneable (See JLS 20.1.5) 107 JFR_ONLY(INIT_ID(this);) 108 log_array_class_load(this); 109 } 110 111 112 // Initialization of vtables and mirror object is done separately from base_create_array_klass, 113 // since a GC can happen. At this point all instance variables of the ArrayKlass must be setup. 114 void ArrayKlass::complete_create_array_klass(ArrayKlass* k, Klass* super_klass, ModuleEntry* module_entry, TRAPS) { 115 k->initialize_supers(super_klass, nullptr, CHECK); 116 k->vtable().initialize_vtable(); 117 118 // During bootstrapping, before java.base is defined, the module_entry may not be present yet. 119 // These classes will be put on a fixup list and their module fields will be patched once 120 // java.base is defined. 121 assert((module_entry != nullptr) || ((module_entry == nullptr) && !ModuleEntryTable::javabase_defined()), 122 "module entry not available post " JAVA_BASE_NAME " definition"); 123 oop module = (module_entry != nullptr) ? module_entry->module() : (oop)nullptr; 124 java_lang_Class::create_mirror(k, Handle(THREAD, k->class_loader()), Handle(THREAD, module), Handle(), Handle(), CHECK); 125 } 126 127 ArrayKlass* ArrayKlass::array_klass(int n, TRAPS) { 128 129 assert(dimension() <= n, "check order of chain"); 130 int dim = dimension(); 131 if (dim == n) return this; 132 133 // lock-free read needs acquire semantics 134 if (higher_dimension_acquire() == nullptr) { 135 136 // Ensure atomic creation of higher dimensions 137 RecursiveLocker rl(MultiArray_lock, THREAD); 138 139 if (higher_dimension() == nullptr) { 140 // Create multi-dim klass object and link them together 141 ObjArrayKlass* ak = 142 ObjArrayKlass::allocate_objArray_klass(class_loader_data(), dim + 1, this, CHECK_NULL); 143 // use 'release' to pair with lock-free load 144 release_set_higher_dimension(ak); 145 assert(ak->lower_dimension() == this, "lower dimension mismatch"); 146 } 147 } 148 149 ObjArrayKlass* ak = higher_dimension(); 150 assert(ak != nullptr, "should be set"); 151 THREAD->check_possible_safepoint(); 152 return ak->array_klass(n, THREAD); 153 } 154 155 ArrayKlass* ArrayKlass::array_klass_or_null(int n) { 156 157 assert(dimension() <= n, "check order of chain"); 158 int dim = dimension(); 159 if (dim == n) return this; 160 161 // lock-free read needs acquire semantics 162 if (higher_dimension_acquire() == nullptr) { 163 return nullptr; 164 } 165 166 ObjArrayKlass *ak = higher_dimension(); 167 return ak->array_klass_or_null(n); 168 } 169 170 ArrayKlass* ArrayKlass::array_klass(TRAPS) { 171 return array_klass(dimension() + 1, THREAD); 172 } 173 174 ArrayKlass* ArrayKlass::array_klass_or_null() { 175 return array_klass_or_null(dimension() + 1); 176 } 177 178 179 GrowableArray<Klass*>* ArrayKlass::compute_secondary_supers(int num_extra_slots, 180 Array<InstanceKlass*>* transitive_interfaces) { 181 // interfaces = { cloneable_klass, serializable_klass }; 182 assert(num_extra_slots == 0, "sanity of primitive array type"); 183 assert(transitive_interfaces == nullptr, "sanity"); 184 // Must share this for correct bootstrapping! 185 set_secondary_supers(Universe::the_array_interfaces_array(), 186 Universe::the_array_interfaces_bitmap()); 187 return nullptr; 188 } 189 190 objArrayOop ArrayKlass::allocate_arrayArray(int n, int length, TRAPS) { 191 check_array_allocation_length(length, arrayOopDesc::max_array_length(T_ARRAY), CHECK_NULL); 192 size_t size = objArrayOopDesc::object_size(length); 193 ArrayKlass* ak = array_klass(n + dimension(), CHECK_NULL); 194 objArrayOop o = (objArrayOop)Universe::heap()->array_allocate(ak, size, length, 195 /* do_zero */ true, CHECK_NULL); 196 // initialization to null not necessary, area already cleared 197 return o; 198 } 199 200 // JVMTI support 201 202 jint ArrayKlass::jvmti_class_status() const { 203 return JVMTI_CLASS_STATUS_ARRAY; 204 } 205 206 void ArrayKlass::metaspace_pointers_do(MetaspaceClosure* it) { 207 Klass::metaspace_pointers_do(it); 208 209 ResourceMark rm; 210 log_trace(cds)("Iter(ArrayKlass): %p (%s)", this, external_name()); 211 212 // need to cast away volatile 213 it->push((Klass**)&_higher_dimension); 214 it->push((Klass**)&_lower_dimension); 215 } 216 217 #if INCLUDE_CDS 218 void ArrayKlass::remove_unshareable_info() { 219 Klass::remove_unshareable_info(); 220 if (_higher_dimension != nullptr) { 221 ArrayKlass *ak = higher_dimension(); 222 ak->remove_unshareable_info(); 223 } 224 } 225 226 void ArrayKlass::remove_java_mirror() { 227 Klass::remove_java_mirror(); 228 if (_higher_dimension != nullptr) { 229 ArrayKlass *ak = higher_dimension(); 230 ak->remove_java_mirror(); 231 } 232 } 233 234 void ArrayKlass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) { 235 Klass::restore_unshareable_info(loader_data, protection_domain, CHECK); 236 // Klass recreates the component mirror also 237 238 if (_higher_dimension != nullptr) { 239 ArrayKlass *ak = higher_dimension(); 240 log_array_class_load(ak); 241 ak->restore_unshareable_info(loader_data, protection_domain, CHECK); 242 } 243 } 244 245 void ArrayKlass::cds_print_value_on(outputStream* st) const { 246 assert(is_klass(), "must be klass"); 247 st->print(" - array: %s", internal_name()); 248 if (_higher_dimension != nullptr) { 249 ArrayKlass* ak = higher_dimension(); 250 st->cr(); 251 ak->cds_print_value_on(st); 252 } 253 } 254 #endif // INCLUDE_CDS 255 256 void ArrayKlass::log_array_class_load(Klass* k) { 257 LogTarget(Debug, class, load, array) lt; 258 if (lt.is_enabled()) { 259 LogStream ls(lt); 260 ResourceMark rm; 261 ls.print("%s", k->name()->as_klass_external_name()); 262 if (MetaspaceShared::is_shared_dynamic((void*)k)) { 263 ls.print(" source: shared objects file (top)"); 264 } else if (MetaspaceShared::is_shared_static((void*)k)) { 265 ls.print(" source: shared objects file"); 266 } 267 ls.cr(); 268 } 269 } 270 271 // Printing 272 273 void ArrayKlass::print_on(outputStream* st) const { 274 assert(is_klass(), "must be klass"); 275 Klass::print_on(st); 276 } 277 278 void ArrayKlass::print_value_on(outputStream* st) const { 279 assert(is_klass(), "must be klass"); 280 for(int index = 0; index < dimension(); index++) { 281 st->print("[]"); 282 } 283 } 284 285 void ArrayKlass::oop_print_on(oop obj, outputStream* st) { 286 assert(obj->is_array(), "must be array"); 287 Klass::oop_print_on(obj, st); 288 st->print_cr(" - length: %d", arrayOop(obj)->length()); 289 } 290 291 292 // Verification 293 294 void ArrayKlass::verify_on(outputStream* st) { 295 Klass::verify_on(st); 296 } 297 298 void ArrayKlass::oop_verify_on(oop obj, outputStream* st) { 299 guarantee(obj->is_array(), "must be array"); 300 arrayOop a = arrayOop(obj); 301 guarantee(a->length() >= 0, "array with negative length?"); 302 }