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/symbolTable.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/objArrayKlass.hpp"
42 #include "oops/objArrayOop.hpp"
43 #include "oops/oop.inline.hpp"
44 #include "oops/refArrayKlass.hpp"
45 #include "runtime/handles.inline.hpp"
46
47 void* ArrayKlass::operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw() {
48 return Metaspace::allocate(loader_data, word_size, MetaspaceObj::ClassType, true, THREAD);
49 }
50
51 ArrayKlass::ArrayKlass() {
52 assert(CDSConfig::is_dumping_static_archive() || CDSConfig::is_using_archive(), "only for CDS");
53 }
54
55 int ArrayKlass::static_size(int header_size) {
56 // size of an array klass object
57 assert(header_size <= InstanceKlass::header_size(), "bad header size");
58 // If this assert fails, see comments in base_create_array_klass.
59 header_size = InstanceKlass::header_size();
60 int vtable_len = Universe::base_vtable_size();
61 int size = header_size + vtable_len;
62 return align_metadata_size(size);
63 }
64
65
66 InstanceKlass* ArrayKlass::java_super() const {
67 if (super() == nullptr) return nullptr; // bootstrap case
68 // Array klasses have primary supertypes which are not reported to Java.
69 // Example super chain: String[][] -> Object[][] -> Object[] -> Object
70 return vmClasses::Object_klass();
71 }
72
73
74 oop ArrayKlass::multi_allocate(int rank, jint* sizes, TRAPS) {
75 ShouldNotReachHere();
76 return nullptr;
77 }
78
79 // find field according to JVM spec 5.4.3.2, returns the klass in which the field is defined
80 Klass* ArrayKlass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
81 // There are no fields in an array klass but look to the super class (Object)
82 assert(super(), "super klass must be present");
83 return super()->find_field(name, sig, fd);
84 }
85
86 Method* ArrayKlass::uncached_lookup_method(const Symbol* name,
87 const Symbol* signature,
88 OverpassLookupMode overpass_mode,
89 PrivateLookupMode private_mode) const {
90 // There are no methods in an array klass but the super class (Object) has some
91 assert(super(), "super klass must be present");
92 // Always ignore overpass methods in superclasses, although technically the
93 // super klass of an array, (j.l.Object) should not have
94 // any overpass methods present.
95 return super()->uncached_lookup_method(name, signature, OverpassLookupMode::skip, private_mode);
96 }
97
98 ArrayKlass::ArrayKlass(Symbol* name, KlassKind kind, ArrayProperties props, markWord prototype_header) :
99 Klass(kind, prototype_header),
100 _dimension(1),
101 _properties(props),
102 _higher_dimension(nullptr),
103 _lower_dimension(nullptr) {
104 // Arrays don't add any new methods, so their vtable is the same size as
105 // the vtable of klass Object.
106 set_vtable_length(Universe::base_vtable_size());
107 set_name(name);
108 set_super(Universe::is_bootstrapping() ? nullptr : vmClasses::Object_klass());
109 set_layout_helper(Klass::_lh_neutral_value);
110 set_is_cloneable(); // All arrays are considered to be cloneable (See JLS 20.1.5)
111 JFR_ONLY(INIT_ID(this);)
112 log_array_class_load(this);
113 }
114
115 Symbol* ArrayKlass::create_element_klass_array_name(Klass* element_klass, TRAPS) {
116 ResourceMark rm(THREAD);
117 Symbol* name = nullptr;
118 char *name_str = element_klass->name()->as_C_string();
119 int len = element_klass->name()->utf8_length();
120 char *new_str = NEW_RESOURCE_ARRAY(char, len + 4);
121 int idx = 0;
122 new_str[idx++] = JVM_SIGNATURE_ARRAY;
123 if (element_klass->is_instance_klass()) { // it could be an array or simple type
124 new_str[idx++] = JVM_SIGNATURE_CLASS;
125 }
126 memcpy(&new_str[idx], name_str, len * sizeof(char));
127 idx += len;
128 if (element_klass->is_instance_klass()) {
129 new_str[idx++] = JVM_SIGNATURE_ENDCLASS;
130 }
131 new_str[idx++] = '\0';
132 return SymbolTable::new_symbol(new_str);
133 }
134
135 // Initialization of vtables and mirror object is done separately from base_create_array_klass,
136 // since a GC can happen. At this point all instance variables of the ArrayKlass must be setup.
137 void ArrayKlass::complete_create_array_klass(ArrayKlass* k, Klass* super_klass, ModuleEntry* module_entry, TRAPS) {
138 k->initialize_supers(super_klass, nullptr, CHECK);
139 k->vtable().initialize_vtable();
140
141 // During bootstrapping, before java.base is defined, the module_entry may not be present yet.
142 // These classes will be put on a fixup list and their module fields will be patched once
143 // java.base is defined.
144 assert((module_entry != nullptr) || ((module_entry == nullptr) && !ModuleEntryTable::javabase_defined()),
145 "module entry not available post " JAVA_BASE_NAME " definition");
146 oop module = (module_entry != nullptr) ? module_entry->module() : (oop)nullptr;
147
148 if (k->is_refArray_klass() || k->is_flatArray_klass()) {
149 assert(super_klass != nullptr, "Must be");
150 assert(k->super() != nullptr, "Must be");
151 assert(k->super() == super_klass, "Must be");
152 Handle mirror(THREAD, super_klass->java_mirror());
153 k->set_java_mirror(mirror);
154 } else {
155 java_lang_Class::create_mirror(k, Handle(THREAD, k->class_loader()), Handle(THREAD, module), Handle(), Handle(), CHECK);
156 }
157 }
158
159 ArrayKlass* ArrayKlass::array_klass(int n, TRAPS) {
160
161 assert(dimension() <= n, "check order of chain");
162 int dim = dimension();
163 if (dim == n) return this;
164
165 // lock-free read needs acquire semantics
166 if (higher_dimension_acquire() == nullptr) {
167
168 // Ensure atomic creation of higher dimensions
169 RecursiveLocker rl(MultiArray_lock, THREAD);
170
171 if (higher_dimension() == nullptr) {
172 // Create multi-dim klass object and link them together
173 ObjArrayKlass* ak = RefArrayKlass::allocate_objArray_klass(class_loader_data(), dim + 1, this, CHECK_NULL);
174 // use 'release' to pair with lock-free load
175 release_set_higher_dimension(ak);
176 assert(ak->lower_dimension() == this, "lower dimension mismatch");
177 }
178 }
179
180 ObjArrayKlass* ak = higher_dimension();
181 assert(ak != nullptr, "should be set");
182 THREAD->check_possible_safepoint();
183 return ak->array_klass(n, THREAD);
184 }
185
186 ArrayKlass* ArrayKlass::array_klass_or_null(int n) {
187
188 assert(dimension() <= n, "check order of chain");
189 int dim = dimension();
190 if (dim == n) return this;
191
192 // lock-free read needs acquire semantics
193 if (higher_dimension_acquire() == nullptr) {
194 return nullptr;
195 }
196
197 ObjArrayKlass *ak = higher_dimension();
198 return ak->array_klass_or_null(n);
199 }
200
201 ArrayKlass* ArrayKlass::array_klass(TRAPS) {
202 return array_klass(dimension() + 1, THREAD);
203 }
204
205 ArrayKlass* ArrayKlass::array_klass_or_null() {
206 return array_klass_or_null(dimension() + 1);
207 }
208
209
210 GrowableArray<Klass*>* ArrayKlass::compute_secondary_supers(int num_extra_slots,
211 Array<InstanceKlass*>* transitive_interfaces) {
212 // interfaces = { cloneable_klass, serializable_klass };
213 assert(num_extra_slots == 0, "sanity of primitive array type");
214 assert(transitive_interfaces == nullptr, "sanity");
215 // Must share this for correct bootstrapping!
216 set_secondary_supers(Universe::the_array_interfaces_array(),
217 Universe::the_array_interfaces_bitmap());
218 return nullptr;
219 }
220
221 objArrayOop ArrayKlass::allocate_arrayArray(int n, int length, TRAPS) {
222 check_array_allocation_length(length, arrayOopDesc::max_array_length(T_ARRAY), CHECK_NULL);
223 size_t size = refArrayOopDesc::object_size(length);
224 ArrayKlass* ak = array_klass(n + dimension(), CHECK_NULL);
225 ObjArrayKlass* oak = ObjArrayKlass::cast(ak)->klass_with_properties(ArrayProperties::DEFAULT, CHECK_NULL);
226 objArrayOop o = (objArrayOop)Universe::heap()->array_allocate(oak, size, length,
227 /* do_zero */ true, CHECK_NULL);
228 // initialization to null not necessary, area already cleared
229 return o;
230 }
231
232 oop ArrayKlass::component_mirror() const {
233 return java_lang_Class::component_mirror(java_mirror());
234 }
235
236 // JVMTI support
237
238 jint ArrayKlass::jvmti_class_status() const {
239 return JVMTI_CLASS_STATUS_ARRAY;
240 }
241
242 void ArrayKlass::metaspace_pointers_do(MetaspaceClosure* it) {
243 Klass::metaspace_pointers_do(it);
244
245 ResourceMark rm;
246 log_trace(aot)("Iter(ArrayKlass): %p (%s)", this, external_name());
247
248 // need to cast away volatile
249 it->push((Klass**)&_higher_dimension);
250 it->push((Klass**)&_lower_dimension);
251 }
252
253 #if INCLUDE_CDS
254 void ArrayKlass::remove_unshareable_info() {
255 Klass::remove_unshareable_info();
256 if (_higher_dimension != nullptr) {
257 ArrayKlass *ak = higher_dimension();
258 ak->remove_unshareable_info();
259 }
260 }
261
262 void ArrayKlass::remove_java_mirror() {
263 Klass::remove_java_mirror();
264 if (_higher_dimension != nullptr) {
265 ArrayKlass *ak = higher_dimension();
266 ak->remove_java_mirror();
267 }
268 }
269
270 void ArrayKlass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) {
271 Klass::restore_unshareable_info(loader_data, protection_domain, CHECK);
272 // Klass recreates the component mirror also
273
274 if (_higher_dimension != nullptr) {
275 ObjArrayKlass *ak = higher_dimension();
276 log_array_class_load(ak);
277 ak->restore_unshareable_info(loader_data, protection_domain, CHECK);
278 }
279 }
280
281 void ArrayKlass::cds_print_value_on(outputStream* st) const {
282 assert(is_klass(), "must be klass");
283 st->print(" - array: %s", internal_name());
284 if (_higher_dimension != nullptr) {
285 ArrayKlass* ak = higher_dimension();
286 st->cr();
287 ak->cds_print_value_on(st);
288 }
289 }
290 #endif // INCLUDE_CDS
291
292 void ArrayKlass::log_array_class_load(Klass* k) {
293 LogTarget(Debug, class, load, array) lt;
294 if (lt.is_enabled()) {
295 LogStream ls(lt);
296 ResourceMark rm;
297 ls.print("%s", k->name()->as_klass_external_name());
298 if (MetaspaceShared::is_shared_dynamic((void*)k)) {
299 ls.print(" source: shared objects file (top)");
300 } else if (MetaspaceShared::is_shared_static((void*)k)) {
301 ls.print(" source: shared objects file");
302 }
303 ls.cr();
304 }
305 }
306
307 // Printing
308
309 void ArrayKlass::print_on(outputStream* st) const {
310 assert(is_klass(), "must be klass");
311 Klass::print_on(st);
312 }
313
314 void ArrayKlass::print_value_on(outputStream* st) const {
315 assert(is_klass(), "must be klass");
316 for(int index = 0; index < dimension(); index++) {
317 st->print("[]");
318 }
319 }
320
321 void ArrayKlass::oop_print_on(oop obj, outputStream* st) {
322 assert(obj->is_array(), "must be array");
323 Klass::oop_print_on(obj, st);
324 st->print_cr(" - length: %d", arrayOop(obj)->length());
325 }
326
327
328 // Verification
329
330 void ArrayKlass::verify_on(outputStream* st) {
331 Klass::verify_on(st);
332 }
333
334 void ArrayKlass::oop_verify_on(oop obj, outputStream* st) {
335 guarantee(obj->is_array(), "must be array");
336 arrayOop a = arrayOop(obj);
337 guarantee(a->length() >= 0, "array with negative length?");
338 }