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() : _properties() {
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 static markWord calc_prototype_header(Klass::KlassKind kind, ArrayProperties props) {
95 switch (kind) {
96 case Klass::KlassKind::TypeArrayKlassKind:
97 return markWord::prototype();
98
99 case Klass::KlassKind::FlatArrayKlassKind:
100 return markWord::flat_array_prototype(props.is_null_restricted());
101
102 case Klass::KlassKind::ObjArrayKlassKind:
103 case Klass::KlassKind::RefArrayKlassKind:
104 if (props.is_null_restricted()) {
105 return markWord::null_free_array_prototype();
106 } else {
107 return markWord::prototype();
108 }
109
110 default:
111 ShouldNotReachHere();
112 };
113 }
114
115 ArrayKlass::ArrayKlass(int n, Symbol* name, KlassKind kind, ArrayProperties props)
116 : Klass(kind, calc_prototype_header(kind, props)),
117 _dimension(n),
118 _higher_dimension(nullptr),
119 _lower_dimension(nullptr),
120 _properties(props) {
121 // Arrays don't add any new methods, so their vtable is the same size as
122 // the vtable of klass Object.
123 set_vtable_length(Universe::base_vtable_size());
124 set_name(name);
125 set_super(Universe::is_bootstrapping() ? nullptr : vmClasses::Object_klass());
126 set_layout_helper(Klass::_lh_neutral_value);
127 // All arrays are considered to be cloneable (See JLS 20.1.5)
128 set_is_cloneable_fast();
129 JFR_ONLY(INIT_ID(this);)
130 log_array_class_load(this);
131 }
132
133
134 // Initialization of vtables and mirror object is done separately from base_create_array_klass,
135 // since a GC can happen. At this point all instance variables of the ArrayKlass must be setup.
136 void ArrayKlass::complete_create_array_klass(ArrayKlass* k, Klass* super_klass, ModuleEntry* module_entry, TRAPS) {
137 k->initialize_supers(super_klass, nullptr, CHECK);
138 k->vtable().initialize_vtable();
139
140 // During bootstrapping, before java.base is defined, the module_entry may not be present yet.
141 // These classes will be put on a fixup list and their module fields will be patched once
142 // java.base is defined.
143 assert((module_entry != nullptr) || ((module_entry == nullptr) && !ModuleEntryTable::javabase_defined()),
144 "module entry not available post " JAVA_BASE_NAME " definition");
145 oop module_oop = (module_entry != nullptr) ? module_entry->module_oop() : (oop)nullptr;
146
147 if (k->is_refined_objArray_klass()) {
148 assert(super_klass != nullptr, "Must be");
149 assert(k->super() != nullptr, "Must be");
150 assert(k->super() == super_klass, "Must be");
151 Handle mirror(THREAD, super_klass->java_mirror());
152 k->set_java_mirror(mirror);
153 } else {
154 java_lang_Class::create_mirror(k, Handle(THREAD, k->class_loader()), Handle(THREAD, module_oop), Handle(), Handle(), CHECK);
155 }
156 }
157
158 ArrayKlass* ArrayKlass::array_klass(int n, TRAPS) {
159
160 assert(dimension() <= n, "check order of chain");
161 int dim = dimension();
162 if (dim == n) return this;
163
164 // lock-free read needs acquire semantics
165 if (higher_dimension_acquire() == nullptr) {
166
167 // Ensure atomic creation of higher dimensions
168 RecursiveLocker rl(MultiArray_lock, THREAD);
169
170 if (higher_dimension() == nullptr) {
171 // Create multi-dim klass object and link them together
172 ObjArrayKlass* ak =
173 ObjArrayKlass::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 oop ArrayKlass::component_mirror() const {
222 return java_lang_Class::component_mirror(java_mirror());
223 }
224
225 ArrayProperties ArrayKlass::array_properties_from_layout(LayoutKind lk) {
226 switch(lk) {
227 case LayoutKind::NULL_FREE_ATOMIC_FLAT:
228 return ArrayProperties::Default().with_null_restricted();
229 case LayoutKind::NULL_FREE_NON_ATOMIC_FLAT:
230 return ArrayProperties::Default().with_null_restricted().with_non_atomic();
231 case LayoutKind::NULLABLE_ATOMIC_FLAT:
232 return ArrayProperties::Default();
233 default:
234 ShouldNotReachHere();
235 return ArrayProperties::Default();
236 }
237 }
238
239 // JVMTI support
240
241 jint ArrayKlass::jvmti_class_status() const {
242 return JVMTI_CLASS_STATUS_ARRAY;
243 }
244
245 void ArrayKlass::metaspace_pointers_do(MetaspaceClosure* it) {
246 Klass::metaspace_pointers_do(it);
247
248 ResourceMark rm;
249 log_trace(aot)("Iter(ArrayKlass): %p (%s)", this, external_name());
250
251 // need to cast away volatile
252 it->push((Klass**)&_higher_dimension);
253 it->push((Klass**)&_lower_dimension);
254 }
255
256 #if INCLUDE_CDS
257 void ArrayKlass::remove_unshareable_info() {
258 Klass::remove_unshareable_info();
259 if (_higher_dimension != nullptr) {
260 ArrayKlass *ak = higher_dimension();
261 ak->remove_unshareable_info();
262 }
263 }
264
265 void ArrayKlass::remove_java_mirror() {
266 Klass::remove_java_mirror();
267 if (_higher_dimension != nullptr) {
268 ArrayKlass *ak = higher_dimension();
269 ak->remove_java_mirror();
270 }
271 }
272
273 void ArrayKlass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) {
274 Klass::restore_unshareable_info(loader_data, protection_domain, CHECK);
275 // Klass recreates the component mirror also
276
277 if (_higher_dimension != nullptr) {
278 ObjArrayKlass *ak = higher_dimension();
279 log_array_class_load(ak);
280 ak->restore_unshareable_info(loader_data, protection_domain, CHECK);
281 }
282 }
283
284 void ArrayKlass::cds_print_value_on(outputStream* st) const {
285 assert(is_klass(), "must be klass");
286 st->print(" - array: %s", internal_name());
287 if (_higher_dimension != nullptr) {
288 ArrayKlass* ak = higher_dimension();
289 st->cr();
290 ak->cds_print_value_on(st);
291 }
292 }
293 #endif // INCLUDE_CDS
294
295 void ArrayKlass::log_array_class_load(Klass* k) {
296 LogTarget(Debug, class, load, array) lt;
297 if (lt.is_enabled()) {
298 LogStream ls(lt);
299 ResourceMark rm;
300 ls.print("%s", k->name()->as_klass_external_name());
301 if (AOTMetaspace::in_aot_cache_dynamic_region((void*)k)) {
302 ls.print(" source: shared objects file (top)");
303 } else if (AOTMetaspace::in_aot_cache_static_region((void*)k)) {
304 ls.print(" source: shared objects file");
305 }
306 ls.cr();
307 }
308 }
309
310 // Printing
311
312 void ArrayKlass::print_on(outputStream* st) const {
313 assert(is_klass(), "must be klass");
314 Klass::print_on(st);
315 }
316
317 void ArrayKlass::print_value_on(outputStream* st) const {
318 assert(is_klass(), "must be klass");
319 for(int index = 0; index < dimension(); index++) {
320 st->print("[]");
321 }
322 }
323
324 void ArrayKlass::oop_print_on(oop obj, outputStream* st) {
325 assert(obj->is_array(), "must be array");
326 Klass::oop_print_on(obj, st);
327 st->print_cr(" - length: %d", arrayOop(obj)->length());
328 }
329
330
331 // Verification
332
333 void ArrayKlass::verify_on(outputStream* st) {
334 Klass::verify_on(st);
335 }
336
337 void ArrayKlass::oop_verify_on(oop obj, outputStream* st) {
338 Klass::oop_verify_on(obj, st);
339 guarantee(obj->is_array(), "must be array");
340 arrayOop a = arrayOop(obj);
341 guarantee(a->length() >= 0, "array with negative length?");
342 }