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 // 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_oop = (module_entry != nullptr) ? module_entry->module_oop() : (oop)nullptr;
145
146 if (k->is_refined_objArray_klass()) {
147 assert(super_klass != nullptr, "Must be");
148 assert(k->super() != nullptr, "Must be");
149 assert(k->super() == super_klass, "Must be");
150 Handle mirror(THREAD, super_klass->java_mirror());
151 k->set_java_mirror(mirror);
152 } else {
153 java_lang_Class::create_mirror(k, Handle(THREAD, k->class_loader()), Handle(THREAD, module_oop), Handle(), Handle(), CHECK);
154 }
155 }
156
157 ArrayKlass* ArrayKlass::array_klass(int n, TRAPS) {
158
159 assert(dimension() <= n, "check order of chain");
160 int dim = dimension();
161 if (dim == n) return this;
162
163 // lock-free read needs acquire semantics
164 if (higher_dimension_acquire() == nullptr) {
165
166 // Ensure atomic creation of higher dimensions
167 RecursiveLocker rl(MultiArray_lock, THREAD);
168
169 if (higher_dimension() == nullptr) {
170 // Create multi-dim klass object and link them together
171 ObjArrayKlass* ak =
172 ObjArrayKlass::allocate_objArray_klass(class_loader_data(), dim + 1, this, CHECK_NULL);
173 // use 'release' to pair with lock-free load
174 release_set_higher_dimension(ak);
175 assert(ak->lower_dimension() == this, "lower dimension mismatch");
176 }
177 }
178
179 ObjArrayKlass* ak = higher_dimension();
180 assert(ak != nullptr, "should be set");
181 THREAD->check_possible_safepoint();
182 return ak->array_klass(n, THREAD);
183 }
184
185 ArrayKlass* ArrayKlass::array_klass_or_null(int n) {
186
187 assert(dimension() <= n, "check order of chain");
188 int dim = dimension();
189 if (dim == n) return this;
190
191 // lock-free read needs acquire semantics
192 if (higher_dimension_acquire() == nullptr) {
193 return nullptr;
194 }
195
196 ObjArrayKlass *ak = higher_dimension();
197 return ak->array_klass_or_null(n);
198 }
199
200 ArrayKlass* ArrayKlass::array_klass(TRAPS) {
201 return array_klass(dimension() + 1, THREAD);
202 }
203
204 ArrayKlass* ArrayKlass::array_klass_or_null() {
205 return array_klass_or_null(dimension() + 1);
206 }
207
208
209 GrowableArray<Klass*>* ArrayKlass::compute_secondary_supers(int num_extra_slots,
210 Array<InstanceKlass*>* transitive_interfaces) {
211 // interfaces = { cloneable_klass, serializable_klass };
212 assert(num_extra_slots == 0, "sanity of primitive array type");
213 assert(transitive_interfaces == nullptr, "sanity");
214 // Must share this for correct bootstrapping!
215 set_secondary_supers(Universe::the_array_interfaces_array(),
216 Universe::the_array_interfaces_bitmap());
217 return nullptr;
218 }
219
220 oop ArrayKlass::component_mirror() const {
221 return java_lang_Class::component_mirror(java_mirror());
222 }
223
224 ArrayProperties ArrayKlass::array_properties_from_layout(LayoutKind lk) {
225 switch(lk) {
226 case LayoutKind::NULL_FREE_ATOMIC_FLAT:
227 return ArrayProperties::Default().with_null_restricted();
228 case LayoutKind::NULL_FREE_NON_ATOMIC_FLAT:
229 return ArrayProperties::Default().with_null_restricted().with_non_atomic();
230 case LayoutKind::NULLABLE_ATOMIC_FLAT:
231 return ArrayProperties::Default();
232 default:
233 ShouldNotReachHere();
234 }
235 }
236
237 // JVMTI support
238
239 jint ArrayKlass::jvmti_class_status() const {
240 return JVMTI_CLASS_STATUS_ARRAY;
241 }
242
243 void ArrayKlass::metaspace_pointers_do(MetaspaceClosure* it) {
244 Klass::metaspace_pointers_do(it);
245
246 ResourceMark rm;
247 log_trace(aot)("Iter(ArrayKlass): %p (%s)", this, external_name());
248
249 // need to cast away volatile
250 it->push((Klass**)&_higher_dimension);
251 it->push((Klass**)&_lower_dimension);
252 }
253
254 #if INCLUDE_CDS
255 void ArrayKlass::remove_unshareable_info() {
256 Klass::remove_unshareable_info();
257 if (_higher_dimension != nullptr) {
258 ArrayKlass *ak = higher_dimension();
259 ak->remove_unshareable_info();
260 }
261 }
262
263 void ArrayKlass::remove_java_mirror() {
264 Klass::remove_java_mirror();
265 if (_higher_dimension != nullptr) {
266 ArrayKlass *ak = higher_dimension();
267 ak->remove_java_mirror();
268 }
269 }
270
271 void ArrayKlass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) {
272 Klass::restore_unshareable_info(loader_data, protection_domain, CHECK);
273 // Klass recreates the component mirror also
274
275 if (_higher_dimension != nullptr) {
276 ObjArrayKlass *ak = higher_dimension();
277 log_array_class_load(ak);
278 ak->restore_unshareable_info(loader_data, protection_domain, CHECK);
279 }
280 }
281
282 void ArrayKlass::cds_print_value_on(outputStream* st) const {
283 assert(is_klass(), "must be klass");
284 st->print(" - array: %s", internal_name());
285 if (_higher_dimension != nullptr) {
286 ArrayKlass* ak = higher_dimension();
287 st->cr();
288 ak->cds_print_value_on(st);
289 }
290 }
291 #endif // INCLUDE_CDS
292
293 void ArrayKlass::log_array_class_load(Klass* k) {
294 LogTarget(Debug, class, load, array) lt;
295 if (lt.is_enabled()) {
296 LogStream ls(lt);
297 ResourceMark rm;
298 ls.print("%s", k->name()->as_klass_external_name());
299 if (AOTMetaspace::in_aot_cache_dynamic_region((void*)k)) {
300 ls.print(" source: shared objects file (top)");
301 } else if (AOTMetaspace::in_aot_cache_static_region((void*)k)) {
302 ls.print(" source: shared objects file");
303 }
304 ls.cr();
305 }
306 }
307
308 // Printing
309
310 void ArrayKlass::print_on(outputStream* st) const {
311 assert(is_klass(), "must be klass");
312 Klass::print_on(st);
313 }
314
315 void ArrayKlass::print_value_on(outputStream* st) const {
316 assert(is_klass(), "must be klass");
317 for(int index = 0; index < dimension(); index++) {
318 st->print("[]");
319 }
320 }
321
322 void ArrayKlass::oop_print_on(oop obj, outputStream* st) {
323 assert(obj->is_array(), "must be array");
324 Klass::oop_print_on(obj, st);
325 st->print_cr(" - length: %d", arrayOop(obj)->length());
326 }
327
328
329 // Verification
330
331 void ArrayKlass::verify_on(outputStream* st) {
332 Klass::verify_on(st);
333 }
334
335 void ArrayKlass::oop_verify_on(oop obj, outputStream* st) {
336 Klass::oop_verify_on(obj, st);
337 guarantee(obj->is_array(), "must be array");
338 arrayOop a = arrayOop(obj);
339 guarantee(a->length() >= 0, "array with negative length?");
340 }