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 ArrayProperties ArrayKlass::array_properties_from_layout(LayoutKind lk) {
223 switch(lk) {
224 case LayoutKind::NULL_FREE_ATOMIC_FLAT:
225 return ArrayProperties::Default().with_null_restricted();
226 case LayoutKind::NULL_FREE_NON_ATOMIC_FLAT:
227 return ArrayProperties::Default().with_null_restricted().with_non_atomic();
228 case LayoutKind::NULLABLE_ATOMIC_FLAT:
229 return ArrayProperties::Default();
230 default:
231 ShouldNotReachHere();
232 }
233 }
234
235 // JVMTI support
236
237 jint ArrayKlass::jvmti_class_status() const {
238 return JVMTI_CLASS_STATUS_ARRAY;
239 }
240
241 void ArrayKlass::metaspace_pointers_do(MetaspaceClosure* it) {
242 Klass::metaspace_pointers_do(it);
243
244 ResourceMark rm;
245 log_trace(aot)("Iter(ArrayKlass): %p (%s)", this, external_name());
246
247 // need to cast away volatile
248 it->push((Klass**)&_higher_dimension);
249 it->push((Klass**)&_lower_dimension);
250 }
251
252 #if INCLUDE_CDS
253 void ArrayKlass::remove_unshareable_info() {
254 Klass::remove_unshareable_info();
255 if (_higher_dimension != nullptr) {
256 ArrayKlass *ak = higher_dimension();
257 ak->remove_unshareable_info();
258 }
259 }
260
261 void ArrayKlass::remove_java_mirror() {
262 Klass::remove_java_mirror();
263 if (_higher_dimension != nullptr) {
264 ArrayKlass *ak = higher_dimension();
265 ak->remove_java_mirror();
266 }
267 }
268
269 void ArrayKlass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) {
270 Klass::restore_unshareable_info(loader_data, protection_domain, CHECK);
271 // Klass recreates the component mirror also
272
273 if (_higher_dimension != nullptr) {
274 ObjArrayKlass *ak = higher_dimension();
275 log_array_class_load(ak);
276 ak->restore_unshareable_info(loader_data, protection_domain, CHECK);
277 }
278 }
279
280 void ArrayKlass::cds_print_value_on(outputStream* st) const {
281 assert(is_klass(), "must be klass");
282 st->print(" - array: %s", internal_name());
283 if (_higher_dimension != nullptr) {
284 ArrayKlass* ak = higher_dimension();
285 st->cr();
286 ak->cds_print_value_on(st);
287 }
288 }
289 #endif // INCLUDE_CDS
290
291 void ArrayKlass::log_array_class_load(Klass* k) {
292 LogTarget(Debug, class, load, array) lt;
293 if (lt.is_enabled()) {
294 LogStream ls(lt);
295 ResourceMark rm;
296 ls.print("%s", k->name()->as_klass_external_name());
297 if (AOTMetaspace::in_aot_cache_dynamic_region((void*)k)) {
298 ls.print(" source: shared objects file (top)");
299 } else if (AOTMetaspace::in_aot_cache_static_region((void*)k)) {
300 ls.print(" source: shared objects file");
301 }
302 ls.cr();
303 }
304 }
305
306 // Printing
307
308 void ArrayKlass::print_on(outputStream* st) const {
309 assert(is_klass(), "must be klass");
310 Klass::print_on(st);
311 }
312
313 void ArrayKlass::print_value_on(outputStream* st) const {
314 assert(is_klass(), "must be klass");
315 for(int index = 0; index < dimension(); index++) {
316 st->print("[]");
317 }
318 }
319
320 void ArrayKlass::oop_print_on(oop obj, outputStream* st) {
321 assert(obj->is_array(), "must be array");
322 Klass::oop_print_on(obj, st);
323 st->print_cr(" - length: %d", arrayOop(obj)->length());
324 }
325
326
327 // Verification
328
329 void ArrayKlass::verify_on(outputStream* st) {
330 Klass::verify_on(st);
331 }
332
333 void ArrayKlass::oop_verify_on(oop obj, outputStream* st) {
334 guarantee(obj->is_array(), "must be array");
335 arrayOop a = arrayOop(obj);
336 guarantee(a->length() >= 0, "array with negative length?");
337 }