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 }