1 /* 2 * Copyright (c) 1997, 2024, 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 "cds/cdsConfig.hpp" 27 #include "cds/metaspaceShared.hpp" 28 #include "classfile/javaClasses.hpp" 29 #include "classfile/moduleEntry.hpp" 30 #include "classfile/vmClasses.hpp" 31 #include "classfile/vmSymbols.hpp" 32 #include "gc/shared/collectedHeap.inline.hpp" 33 #include "jvmtifiles/jvmti.h" 34 #include "memory/metaspaceClosure.hpp" 35 #include "memory/resourceArea.hpp" 36 #include "memory/universe.hpp" 37 #include "oops/arrayKlass.inline.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 ArrayKlass::ArrayKlass() { 46 assert(CDSConfig::is_dumping_static_archive() || CDSConfig::is_using_archive(), "only for CDS"); 47 } 48 49 int ArrayKlass::static_size(int header_size) { 50 // size of an array klass object 51 assert(header_size <= InstanceKlass::header_size(), "bad header size"); 52 // If this assert fails, see comments in base_create_array_klass. 53 header_size = InstanceKlass::header_size(); 54 int vtable_len = Universe::base_vtable_size(); 55 int size = header_size + vtable_len; 56 return align_metadata_size(size); 57 } 58 59 60 InstanceKlass* ArrayKlass::java_super() const { 61 if (super() == nullptr) return nullptr; // bootstrap case 62 // Array klasses have primary supertypes which are not reported to Java. 63 // Example super chain: String[][] -> Object[][] -> Object[] -> Object 64 return vmClasses::Object_klass(); 65 } 66 67 68 oop ArrayKlass::multi_allocate(int rank, jint* sizes, TRAPS) { 69 ShouldNotReachHere(); 70 return nullptr; 71 } 72 73 // find field according to JVM spec 5.4.3.2, returns the klass in which the field is defined 74 Klass* ArrayKlass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const { 75 // There are no fields in an array klass but look to the super class (Object) 76 assert(super(), "super klass must be present"); 77 return super()->find_field(name, sig, fd); 78 } 79 80 Method* ArrayKlass::uncached_lookup_method(const Symbol* name, 81 const Symbol* signature, 82 OverpassLookupMode overpass_mode, 83 PrivateLookupMode private_mode) const { 84 // There are no methods in an array klass but the super class (Object) has some 85 assert(super(), "super klass must be present"); 86 // Always ignore overpass methods in superclasses, although technically the 87 // super klass of an array, (j.l.Object) should not have 88 // any overpass methods present. 89 return super()->uncached_lookup_method(name, signature, OverpassLookupMode::skip, private_mode); 90 } 91 92 ArrayKlass::ArrayKlass(Symbol* name, KlassKind kind) : 93 Klass(kind), 94 _dimension(1), 95 _higher_dimension(nullptr), 96 _lower_dimension(nullptr) { 97 // Arrays don't add any new methods, so their vtable is the same size as 98 // the vtable of klass Object. 99 set_vtable_length(Universe::base_vtable_size()); 100 set_name(name); 101 set_super(Universe::is_bootstrapping() ? nullptr : vmClasses::Object_klass()); 102 set_layout_helper(Klass::_lh_neutral_value); 103 set_is_cloneable(); // All arrays are considered to be cloneable (See JLS 20.1.5) 104 JFR_ONLY(INIT_ID(this);) 105 log_array_class_load(this); 106 } 107 108 109 // Initialization of vtables and mirror object is done separately from base_create_array_klass, 110 // since a GC can happen. At this point all instance variables of the ArrayKlass must be setup. 111 void ArrayKlass::complete_create_array_klass(ArrayKlass* k, Klass* super_klass, ModuleEntry* module_entry, TRAPS) { 112 k->initialize_supers(super_klass, nullptr, CHECK); 113 k->vtable().initialize_vtable(); 114 115 // During bootstrapping, before java.base is defined, the module_entry may not be present yet. 116 // These classes will be put on a fixup list and their module fields will be patched once 117 // java.base is defined. 118 assert((module_entry != nullptr) || ((module_entry == nullptr) && !ModuleEntryTable::javabase_defined()), 119 "module entry not available post " JAVA_BASE_NAME " definition"); 120 oop module = (module_entry != nullptr) ? module_entry->module() : (oop)nullptr; 121 java_lang_Class::create_mirror(k, Handle(THREAD, k->class_loader()), Handle(THREAD, module), Handle(), Handle(), CHECK); 122 } 123 124 ArrayKlass* ArrayKlass::array_klass(int n, TRAPS) { 125 126 assert(dimension() <= n, "check order of chain"); 127 int dim = dimension(); 128 if (dim == n) return this; 129 130 // lock-free read needs acquire semantics 131 if (higher_dimension_acquire() == nullptr) { 132 133 // Ensure atomic creation of higher dimensions 134 RecursiveLocker rl(MultiArray_lock, THREAD); 135 136 if (higher_dimension() == nullptr) { 137 // Create multi-dim klass object and link them together 138 ObjArrayKlass* ak = 139 ObjArrayKlass::allocate_objArray_klass(class_loader_data(), dim + 1, this, CHECK_NULL); 140 // use 'release' to pair with lock-free load 141 release_set_higher_dimension(ak); 142 assert(ak->lower_dimension() == this, "lower dimension mismatch"); 143 } 144 } 145 146 ObjArrayKlass* ak = higher_dimension(); 147 assert(ak != nullptr, "should be set"); 148 THREAD->check_possible_safepoint(); 149 return ak->array_klass(n, THREAD); 150 } 151 152 ArrayKlass* ArrayKlass::array_klass_or_null(int n) { 153 154 assert(dimension() <= n, "check order of chain"); 155 int dim = dimension(); 156 if (dim == n) return this; 157 158 // lock-free read needs acquire semantics 159 if (higher_dimension_acquire() == nullptr) { 160 return nullptr; 161 } 162 163 ObjArrayKlass *ak = higher_dimension(); 164 return ak->array_klass_or_null(n); 165 } 166 167 ArrayKlass* ArrayKlass::array_klass(TRAPS) { 168 return array_klass(dimension() + 1, THREAD); 169 } 170 171 ArrayKlass* ArrayKlass::array_klass_or_null() { 172 return array_klass_or_null(dimension() + 1); 173 } 174 175 176 GrowableArray<Klass*>* ArrayKlass::compute_secondary_supers(int num_extra_slots, 177 Array<InstanceKlass*>* transitive_interfaces) { 178 // interfaces = { cloneable_klass, serializable_klass }; 179 assert(num_extra_slots == 0, "sanity of primitive array type"); 180 assert(transitive_interfaces == nullptr, "sanity"); 181 // Must share this for correct bootstrapping! 182 set_secondary_supers(Universe::the_array_interfaces_array(), 183 Universe::the_array_interfaces_bitmap()); 184 return nullptr; 185 } 186 187 objArrayOop ArrayKlass::allocate_arrayArray(int n, int length, TRAPS) { 188 check_array_allocation_length(length, arrayOopDesc::max_array_length(T_ARRAY), CHECK_NULL); 189 size_t size = objArrayOopDesc::object_size(length); 190 ArrayKlass* ak = array_klass(n + dimension(), CHECK_NULL); 191 objArrayOop o = (objArrayOop)Universe::heap()->array_allocate(ak, size, length, 192 /* do_zero */ true, CHECK_NULL); 193 // initialization to null not necessary, area already cleared 194 return o; 195 } 196 197 jint ArrayKlass::compute_modifier_flags() const { 198 return JVM_ACC_ABSTRACT | JVM_ACC_FINAL | JVM_ACC_PUBLIC; 199 } 200 201 // JVMTI support 202 203 jint ArrayKlass::jvmti_class_status() const { 204 return JVMTI_CLASS_STATUS_ARRAY; 205 } 206 207 void ArrayKlass::metaspace_pointers_do(MetaspaceClosure* it) { 208 Klass::metaspace_pointers_do(it); 209 210 ResourceMark rm; 211 log_trace(cds)("Iter(ArrayKlass): %p (%s)", this, external_name()); 212 213 // need to cast away volatile 214 it->push((Klass**)&_higher_dimension); 215 it->push((Klass**)&_lower_dimension); 216 } 217 218 #if INCLUDE_CDS 219 void ArrayKlass::remove_unshareable_info() { 220 Klass::remove_unshareable_info(); 221 if (_higher_dimension != nullptr) { 222 ArrayKlass *ak = higher_dimension(); 223 ak->remove_unshareable_info(); 224 } 225 } 226 227 void ArrayKlass::remove_java_mirror() { 228 Klass::remove_java_mirror(); 229 if (_higher_dimension != nullptr) { 230 ArrayKlass *ak = higher_dimension(); 231 ak->remove_java_mirror(); 232 } 233 } 234 235 void ArrayKlass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) { 236 Klass::restore_unshareable_info(loader_data, protection_domain, CHECK); 237 // Klass recreates the component mirror also 238 239 if (_higher_dimension != nullptr) { 240 ArrayKlass *ak = higher_dimension(); 241 log_array_class_load(ak); 242 ak->restore_unshareable_info(loader_data, protection_domain, CHECK); 243 } 244 } 245 246 void ArrayKlass::cds_print_value_on(outputStream* st) const { 247 assert(is_klass(), "must be klass"); 248 st->print(" - array: %s", internal_name()); 249 if (_higher_dimension != nullptr) { 250 ArrayKlass* ak = higher_dimension(); 251 st->cr(); 252 ak->cds_print_value_on(st); 253 } 254 } 255 #endif // INCLUDE_CDS 256 257 void ArrayKlass::log_array_class_load(Klass* k) { 258 LogTarget(Debug, class, load, array) lt; 259 if (lt.is_enabled()) { 260 LogStream ls(lt); 261 ResourceMark rm; 262 ls.print("%s", k->name()->as_klass_external_name()); 263 if (MetaspaceShared::is_shared_dynamic((void*)k)) { 264 ls.print(" source: shared objects file (top)"); 265 } else if (MetaspaceShared::is_shared_static((void*)k)) { 266 ls.print(" source: shared objects file"); 267 } 268 ls.cr(); 269 } 270 } 271 272 // Printing 273 274 void ArrayKlass::print_on(outputStream* st) const { 275 assert(is_klass(), "must be klass"); 276 Klass::print_on(st); 277 } 278 279 void ArrayKlass::print_value_on(outputStream* st) const { 280 assert(is_klass(), "must be klass"); 281 for(int index = 0; index < dimension(); index++) { 282 st->print("[]"); 283 } 284 } 285 286 void ArrayKlass::oop_print_on(oop obj, outputStream* st) { 287 assert(obj->is_array(), "must be array"); 288 Klass::oop_print_on(obj, st); 289 st->print_cr(" - length: %d", arrayOop(obj)->length()); 290 } 291 292 293 // Verification 294 295 void ArrayKlass::verify_on(outputStream* st) { 296 Klass::verify_on(st); 297 } 298 299 void ArrayKlass::oop_verify_on(oop obj, outputStream* st) { 300 guarantee(obj->is_array(), "must be array"); 301 arrayOop a = arrayOop(obj); 302 guarantee(a->length() >= 0, "array with negative length?"); 303 }