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