1 /*
2 * Copyright (c) 1997, 2023, 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 "precompiled.hpp"
26 #include "cds/cdsConfig.hpp"
27 #include "cds/metaspaceShared.hpp"
28 #include "classfile/javaClasses.hpp"
29 #include "classfile/moduleEntry.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/objArrayOop.hpp"
42 #include "oops/oop.inline.hpp"
43 #include "runtime/handles.inline.hpp"
44
45 ArrayKlass::ArrayKlass() {
46 assert(CDSConfig::is_dumping_static_archive() || UseSharedSpaces, "only for CDS");
47 }
48
49 int ArrayKlass::static_size(int header_size) {
50 // size of an array klass object
51 assert(header_size <= InstanceKlass::header_size(), "bad header size");
52 // If this assert fails, see comments in base_create_array_klass.
53 header_size = InstanceKlass::header_size();
54 int vtable_len = Universe::base_vtable_size();
55 int size = header_size + vtable_len;
56 return align_metadata_size(size);
57 }
58
59
60 InstanceKlass* ArrayKlass::java_super() const {
61 if (super() == nullptr) return nullptr; // bootstrap case
62 // Array klasses have primary supertypes which are not reported to Java.
63 // Example super chain: String[][] -> Object[][] -> Object[] -> Object
64 return vmClasses::Object_klass();
65 }
66
67
68 oop ArrayKlass::multi_allocate(int rank, jint* sizes, TRAPS) {
69 ShouldNotReachHere();
70 return nullptr;
71 }
72
73 // find field according to JVM spec 5.4.3.2, returns the klass in which the field is defined
74 Klass* ArrayKlass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
75 // There are no fields in an array klass but look to the super class (Object)
76 assert(super(), "super klass must be present");
77 return super()->find_field(name, sig, fd);
78 }
79
80 Method* ArrayKlass::uncached_lookup_method(const Symbol* name,
81 const Symbol* signature,
82 OverpassLookupMode overpass_mode,
83 PrivateLookupMode private_mode) const {
84 // There are no methods in an array klass but the super class (Object) has some
85 assert(super(), "super klass must be present");
86 // Always ignore overpass methods in superclasses, although technically the
87 // super klass of an array, (j.l.Object) should not have
88 // any overpass methods present.
89 return super()->uncached_lookup_method(name, signature, OverpassLookupMode::skip, private_mode);
90 }
91
92 ArrayKlass::ArrayKlass(Symbol* name, KlassKind kind) :
93 Klass(kind),
94 _dimension(1),
95 _higher_dimension(nullptr),
96 _lower_dimension(nullptr) {
97 // Arrays don't add any new methods, so their vtable is the same size as
98 // the vtable of klass Object.
99 set_vtable_length(Universe::base_vtable_size());
100 set_name(name);
101 set_super(Universe::is_bootstrapping() ? nullptr : vmClasses::Object_klass());
102 set_layout_helper(Klass::_lh_neutral_value);
103 set_is_cloneable(); // All arrays are considered to be cloneable (See JLS 20.1.5)
104 JFR_ONLY(INIT_ID(this);)
105 log_array_class_load(this);
106 }
107
108
109 // Initialization of vtables and mirror object is done separately from base_create_array_klass,
110 // since a GC can happen. At this point all instance variables of the ArrayKlass must be setup.
111 void ArrayKlass::complete_create_array_klass(ArrayKlass* k, Klass* super_klass, ModuleEntry* module_entry, TRAPS) {
112 k->initialize_supers(super_klass, nullptr, CHECK);
113 k->vtable().initialize_vtable();
114
115 // During bootstrapping, before java.base is defined, the module_entry may not be present yet.
116 // These classes will be put on a fixup list and their module fields will be patched once
117 // java.base is defined.
118 assert((module_entry != nullptr) || ((module_entry == nullptr) && !ModuleEntryTable::javabase_defined()),
119 "module entry not available post " JAVA_BASE_NAME " definition");
120 oop module = (module_entry != nullptr) ? module_entry->module() : (oop)nullptr;
121 java_lang_Class::create_mirror(k, Handle(THREAD, k->class_loader()), Handle(THREAD, module), Handle(), Handle(), CHECK);
122 }
123
124 ArrayKlass* ArrayKlass::array_klass(int n, TRAPS) {
125
126 assert(dimension() <= n, "check order of chain");
127 int dim = dimension();
128 if (dim == n) return this;
129
130 // lock-free read needs acquire semantics
131 if (higher_dimension_acquire() == nullptr) {
132
133 ResourceMark rm(THREAD);
134 {
135 // Ensure atomic creation of higher dimensions
136 MutexLocker mu(THREAD, MultiArray_lock);
137
138 // Check if another thread beat us
139 if (higher_dimension() == nullptr) {
140
141 // Create multi-dim klass object and link them together
142 ObjArrayKlass* ak =
143 ObjArrayKlass::allocate_objArray_klass(class_loader_data(), dim + 1, this, CHECK_NULL);
144 ak->set_lower_dimension(this);
145 // use 'release' to pair with lock-free load
146 release_set_higher_dimension(ak);
147 assert(ak->is_objArray_klass(), "incorrect initialization of ObjArrayKlass");
148 }
149 }
150 }
151
152 ObjArrayKlass *ak = higher_dimension();
153 THREAD->check_possible_safepoint();
154 return ak->array_klass(n, THREAD);
155 }
156
157 ArrayKlass* ArrayKlass::array_klass_or_null(int n) {
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 return nullptr;
166 }
167
168 ObjArrayKlass *ak = higher_dimension();
169 return ak->array_klass_or_null(n);
170 }
171
172 ArrayKlass* ArrayKlass::array_klass(TRAPS) {
173 return array_klass(dimension() + 1, THREAD);
174 }
175
176 ArrayKlass* ArrayKlass::array_klass_or_null() {
177 return array_klass_or_null(dimension() + 1);
178 }
179
180
181 GrowableArray<Klass*>* ArrayKlass::compute_secondary_supers(int num_extra_slots,
182 Array<InstanceKlass*>* transitive_interfaces) {
183 // interfaces = { cloneable_klass, serializable_klass };
184 assert(num_extra_slots == 0, "sanity of primitive array type");
185 assert(transitive_interfaces == nullptr, "sanity");
186 // Must share this for correct bootstrapping!
187 set_secondary_supers(Universe::the_array_interfaces_array());
188 return nullptr;
189 }
190
191 objArrayOop ArrayKlass::allocate_arrayArray(int n, int length, TRAPS) {
192 check_array_allocation_length(length, arrayOopDesc::max_array_length(T_ARRAY), CHECK_NULL);
193 size_t size = objArrayOopDesc::object_size(length);
194 ArrayKlass* ak = array_klass(n + dimension(), CHECK_NULL);
195 objArrayOop o = (objArrayOop)Universe::heap()->array_allocate(ak, size, length,
196 /* do_zero */ true, CHECK_NULL);
197 // initialization to null not necessary, area already cleared
198 return o;
199 }
200
201 jint ArrayKlass::compute_modifier_flags() const {
202 return JVM_ACC_ABSTRACT | JVM_ACC_FINAL | JVM_ACC_PUBLIC;
203 }
204
205 // JVMTI support
206
207 jint ArrayKlass::jvmti_class_status() const {
208 return JVMTI_CLASS_STATUS_ARRAY;
209 }
210
211 void ArrayKlass::metaspace_pointers_do(MetaspaceClosure* it) {
212 Klass::metaspace_pointers_do(it);
213
214 ResourceMark rm;
215 log_trace(cds)("Iter(ArrayKlass): %p (%s)", this, external_name());
216
217 // need to cast away volatile
218 it->push((Klass**)&_higher_dimension);
219 it->push((Klass**)&_lower_dimension);
220 }
221
222 #if INCLUDE_CDS
223 void ArrayKlass::remove_unshareable_info() {
224 Klass::remove_unshareable_info();
225 if (_higher_dimension != nullptr) {
226 ArrayKlass *ak = higher_dimension();
227 ak->remove_unshareable_info();
228 }
229 }
230
231 void ArrayKlass::remove_java_mirror() {
232 Klass::remove_java_mirror();
233 if (_higher_dimension != nullptr) {
234 ArrayKlass *ak = higher_dimension();
235 ak->remove_java_mirror();
236 }
237 }
238
239 void ArrayKlass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) {
240 Klass::restore_unshareable_info(loader_data, protection_domain, CHECK);
241 // Klass recreates the component mirror also
242
243 if (_higher_dimension != nullptr) {
244 ArrayKlass *ak = higher_dimension();
245 log_array_class_load(ak);
246 ak->restore_unshareable_info(loader_data, protection_domain, CHECK);
247 }
248 }
249
250 void ArrayKlass::cds_print_value_on(outputStream* st) const {
251 assert(is_klass(), "must be klass");
252 st->print(" - array: %s", internal_name());
253 if (_higher_dimension != nullptr) {
254 ArrayKlass* ak = higher_dimension();
255 st->cr();
256 ak->cds_print_value_on(st);
257 }
258 }
259 #endif // INCLUDE_CDS
260
261 void ArrayKlass::log_array_class_load(Klass* k) {
262 LogTarget(Debug, class, load, array) lt;
263 if (lt.is_enabled()) {
264 LogStream ls(lt);
265 ResourceMark rm;
266 ls.print("%s", k->name()->as_klass_external_name());
267 if (MetaspaceShared::is_shared_dynamic((void*)k)) {
268 ls.print(" source: shared objects file (top)");
269 } else if (MetaspaceShared::is_shared_static((void*)k)) {
270 ls.print(" source: shared objects file");
271 }
272 ls.cr();
273 }
274 }
275
276 // Printing
277
278 void ArrayKlass::print_on(outputStream* st) const {
279 assert(is_klass(), "must be klass");
280 Klass::print_on(st);
281 }
282
283 void ArrayKlass::print_value_on(outputStream* st) const {
284 assert(is_klass(), "must be klass");
285 for(int index = 0; index < dimension(); index++) {
286 st->print("[]");
287 }
288 }
289
290 void ArrayKlass::oop_print_on(oop obj, outputStream* st) {
291 assert(obj->is_array(), "must be array");
292 Klass::oop_print_on(obj, st);
293 st->print_cr(" - length: %d", arrayOop(obj)->length());
294 }
295
296
297 // Verification
298
299 void ArrayKlass::verify_on(outputStream* st) {
300 Klass::verify_on(st);
301 }
302
303 void ArrayKlass::oop_verify_on(oop obj, outputStream* st) {
304 guarantee(obj->is_array(), "must be array");
305 arrayOop a = arrayOop(obj);
306 guarantee(a->length() >= 0, "array with negative length?");
307 }