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