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 // All arrays are considered to be cloneable (See JLS 20.1.5)
107 set_is_cloneable_fast();
108 JFR_ONLY(INIT_ID(this);)
109 log_array_class_load(this);
110 }
111
112 Symbol* ArrayKlass::create_element_klass_array_name(Klass* element_klass, TRAPS) {
113 ResourceMark rm(THREAD);
114 Symbol* name = nullptr;
115 char *name_str = element_klass->name()->as_C_string();
116 int len = element_klass->name()->utf8_length();
117 char *new_str = NEW_RESOURCE_ARRAY(char, len + 4);
118 int idx = 0;
119 new_str[idx++] = JVM_SIGNATURE_ARRAY;
120 if (element_klass->is_instance_klass()) { // it could be an array or simple type
121 new_str[idx++] = JVM_SIGNATURE_CLASS;
122 }
123 memcpy(&new_str[idx], name_str, len * sizeof(char));
124 idx += len;
125 if (element_klass->is_instance_klass()) {
126 new_str[idx++] = JVM_SIGNATURE_ENDCLASS;
127 }
128 new_str[idx++] = '\0';
129 return SymbolTable::new_symbol(new_str);
130 }
131
132 // Initialization of vtables and mirror object is done separately from base_create_array_klass,
133 // since a GC can happen. At this point all instance variables of the ArrayKlass must be setup.
134 void ArrayKlass::complete_create_array_klass(ArrayKlass* k, Klass* super_klass, ModuleEntry* module_entry, TRAPS) {
135 k->initialize_supers(super_klass, nullptr, CHECK);
136 k->vtable().initialize_vtable();
137
138 // During bootstrapping, before java.base is defined, the module_entry may not be present yet.
139 // These classes will be put on a fixup list and their module fields will be patched once
140 // java.base is defined.
141 assert((module_entry != nullptr) || ((module_entry == nullptr) && !ModuleEntryTable::javabase_defined()),
142 "module entry not available post " JAVA_BASE_NAME " definition");
143 oop module_oop = (module_entry != nullptr) ? module_entry->module_oop() : (oop)nullptr;
144
145 if (k->is_refArray_klass() || k->is_flatArray_klass()) {
146 assert(super_klass != nullptr, "Must be");
147 assert(k->super() != nullptr, "Must be");
148 assert(k->super() == super_klass, "Must be");
149 Handle mirror(THREAD, super_klass->java_mirror());
150 k->set_java_mirror(mirror);
151 } else {
152 java_lang_Class::create_mirror(k, Handle(THREAD, k->class_loader()), Handle(THREAD, module_oop), Handle(), Handle(), CHECK);
153 }
154 }
155
156 ArrayKlass* ArrayKlass::array_klass(int n, TRAPS) {
157
158 assert(dimension() <= n, "check order of chain");
159 int dim = dimension();
160 if (dim == n) return this;
161
162 // lock-free read needs acquire semantics
163 if (higher_dimension_acquire() == nullptr) {
164
165 // Ensure atomic creation of higher dimensions
166 RecursiveLocker rl(MultiArray_lock, THREAD);
167
168 if (higher_dimension() == nullptr) {
169 // Create multi-dim klass object and link them together
170 ObjArrayKlass* ak = RefArrayKlass::allocate_objArray_klass(class_loader_data(), dim + 1, this, CHECK_NULL);
171 // use 'release' to pair with lock-free load
172 release_set_higher_dimension(ak);
173 assert(ak->lower_dimension() == this, "lower dimension mismatch");
174 }
175 }
176
177 ObjArrayKlass* ak = higher_dimension();
178 assert(ak != nullptr, "should be set");
179 THREAD->check_possible_safepoint();
180 return ak->array_klass(n, THREAD);
181 }
182
183 ArrayKlass* ArrayKlass::array_klass_or_null(int n) {
184
185 assert(dimension() <= n, "check order of chain");
186 int dim = dimension();
187 if (dim == n) return this;
188
189 // lock-free read needs acquire semantics
190 if (higher_dimension_acquire() == nullptr) {
191 return nullptr;
192 }
193
194 ObjArrayKlass *ak = higher_dimension();
195 return ak->array_klass_or_null(n);
196 }
197
198 ArrayKlass* ArrayKlass::array_klass(TRAPS) {
199 return array_klass(dimension() + 1, THREAD);
200 }
201
202 ArrayKlass* ArrayKlass::array_klass_or_null() {
203 return array_klass_or_null(dimension() + 1);
204 }
205
206
207 GrowableArray<Klass*>* ArrayKlass::compute_secondary_supers(int num_extra_slots,
208 Array<InstanceKlass*>* transitive_interfaces) {
209 // interfaces = { cloneable_klass, serializable_klass };
210 assert(num_extra_slots == 0, "sanity of primitive array type");
211 assert(transitive_interfaces == nullptr, "sanity");
212 // Must share this for correct bootstrapping!
213 set_secondary_supers(Universe::the_array_interfaces_array(),
214 Universe::the_array_interfaces_bitmap());
215 return nullptr;
216 }
217
218 oop ArrayKlass::component_mirror() const {
219 return java_lang_Class::component_mirror(java_mirror());
220 }
221
222 ArrayKlass::ArrayProperties ArrayKlass::array_properties_from_layout(LayoutKind lk) {
223 ArrayKlass::ArrayProperties props = ArrayKlass::ArrayProperties::DEFAULT;
224 switch(lk) {
225 case LayoutKind::NULL_FREE_ATOMIC_FLAT:
226 props = ArrayKlass::ArrayProperties::NULL_RESTRICTED;
227 break;
228 case LayoutKind::NULL_FREE_NON_ATOMIC_FLAT:
229 props = (ArrayKlass::ArrayProperties)(ArrayKlass::ArrayProperties::NULL_RESTRICTED | ArrayKlass::ArrayProperties::NON_ATOMIC);
230 break;
231 case LayoutKind::NULLABLE_ATOMIC_FLAT:
232 props = ArrayKlass::ArrayProperties::DEFAULT;
233 break;
234 default:
235 ShouldNotReachHere();
236 }
237 return props;
238 }
239
240 const char* ArrayKlass::array_properties_as_string(ArrayProperties props) {
241 // Caller must have set a ResourceMark
242 stringStream ss;
243 if (props == DEFAULT) {
244 ss.print("DEFAULT (NULLABLE ATOMIC)");
245 } else {
246 ss.print("%s", ((props & NULL_RESTRICTED) != 0) ? "NULL_RESTRICTED " : "NULLABLE ");
247 ss.print("%s", ((props & NON_ATOMIC) != 0) ? "NON_ATOMIC " : "ATOMIC ");
248 }
249 return ss.as_string();
250 }
251
252
253 // JVMTI support
254
255 jint ArrayKlass::jvmti_class_status() const {
256 return JVMTI_CLASS_STATUS_ARRAY;
257 }
258
259 void ArrayKlass::metaspace_pointers_do(MetaspaceClosure* it) {
260 Klass::metaspace_pointers_do(it);
261
262 ResourceMark rm;
263 log_trace(aot)("Iter(ArrayKlass): %p (%s)", this, external_name());
264
265 // need to cast away volatile
266 it->push((Klass**)&_higher_dimension);
267 it->push((Klass**)&_lower_dimension);
268 }
269
270 #if INCLUDE_CDS
271 void ArrayKlass::remove_unshareable_info() {
272 Klass::remove_unshareable_info();
273 if (_higher_dimension != nullptr) {
274 ArrayKlass *ak = higher_dimension();
275 ak->remove_unshareable_info();
276 }
277 }
278
279 void ArrayKlass::remove_java_mirror() {
280 Klass::remove_java_mirror();
281 if (_higher_dimension != nullptr) {
282 ArrayKlass *ak = higher_dimension();
283 ak->remove_java_mirror();
284 }
285 }
286
287 void ArrayKlass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) {
288 Klass::restore_unshareable_info(loader_data, protection_domain, CHECK);
289 // Klass recreates the component mirror also
290
291 if (_higher_dimension != nullptr) {
292 ObjArrayKlass *ak = higher_dimension();
293 log_array_class_load(ak);
294 ak->restore_unshareable_info(loader_data, protection_domain, CHECK);
295 }
296 }
297
298 void ArrayKlass::cds_print_value_on(outputStream* st) const {
299 assert(is_klass(), "must be klass");
300 st->print(" - array: %s", internal_name());
301 if (_higher_dimension != nullptr) {
302 ArrayKlass* ak = higher_dimension();
303 st->cr();
304 ak->cds_print_value_on(st);
305 }
306 }
307 #endif // INCLUDE_CDS
308
309 void ArrayKlass::log_array_class_load(Klass* k) {
310 LogTarget(Debug, class, load, array) lt;
311 if (lt.is_enabled()) {
312 LogStream ls(lt);
313 ResourceMark rm;
314 ls.print("%s", k->name()->as_klass_external_name());
315 if (AOTMetaspace::in_aot_cache_dynamic_region((void*)k)) {
316 ls.print(" source: shared objects file (top)");
317 } else if (AOTMetaspace::in_aot_cache_static_region((void*)k)) {
318 ls.print(" source: shared objects file");
319 }
320 ls.cr();
321 }
322 }
323
324 // Printing
325
326 void ArrayKlass::print_on(outputStream* st) const {
327 assert(is_klass(), "must be klass");
328 Klass::print_on(st);
329 }
330
331 void ArrayKlass::print_value_on(outputStream* st) const {
332 assert(is_klass(), "must be klass");
333 for(int index = 0; index < dimension(); index++) {
334 st->print("[]");
335 }
336 }
337
338 void ArrayKlass::oop_print_on(oop obj, outputStream* st) {
339 assert(obj->is_array(), "must be array");
340 Klass::oop_print_on(obj, st);
341 st->print_cr(" - length: %d", arrayOop(obj)->length());
342 }
343
344
345 // Verification
346
347 void ArrayKlass::verify_on(outputStream* st) {
348 Klass::verify_on(st);
349 }
350
351 void ArrayKlass::oop_verify_on(oop obj, outputStream* st) {
352 guarantee(obj->is_array(), "must be array");
353 arrayOop a = arrayOop(obj);
354 guarantee(a->length() >= 0, "array with negative length?");
355 }