1 /*
2 * Copyright (c) 1997, 2024, 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/symbolTable.hpp"
31 #include "classfile/vmClasses.hpp"
32 #include "classfile/vmSymbols.hpp"
33 #include "gc/shared/collectedHeap.inline.hpp"
34 #include "jvmtifiles/jvmti.h"
35 #include "memory/metaspaceClosure.hpp"
36 #include "memory/resourceArea.hpp"
37 #include "memory/universe.hpp"
38 #include "oops/arrayKlass.inline.hpp"
39 #include "oops/arrayOop.hpp"
40 #include "oops/instanceKlass.hpp"
41 #include "oops/klass.inline.hpp"
42 #include "oops/objArrayKlass.hpp"
43 #include "oops/objArrayOop.hpp"
44 #include "oops/oop.inline.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) :
95 Klass(kind),
96 _dimension(1),
97 _higher_dimension(nullptr),
98 _lower_dimension(nullptr) {
99 // Arrays don't add any new methods, so their vtable is the same size as
100 // the vtable of klass Object.
101 set_vtable_length(Universe::base_vtable_size());
102 set_name(name);
103 set_super(Universe::is_bootstrapping() ? nullptr : vmClasses::Object_klass());
104 set_layout_helper(Klass::_lh_neutral_value);
105 set_is_cloneable(); // All arrays are considered to be cloneable (See JLS 20.1.5)
106 JFR_ONLY(INIT_ID(this);)
107 log_array_class_load(this);
108 }
109
110 Symbol* ArrayKlass::create_element_klass_array_name(Klass* element_klass, TRAPS) {
111 ResourceMark rm(THREAD);
112 Symbol* name = nullptr;
113 char *name_str = element_klass->name()->as_C_string();
114 int len = element_klass->name()->utf8_length();
115 char *new_str = NEW_RESOURCE_ARRAY(char, len + 4);
116 int idx = 0;
117 new_str[idx++] = JVM_SIGNATURE_ARRAY;
118 if (element_klass->is_instance_klass()) { // it could be an array or simple type
119 new_str[idx++] = JVM_SIGNATURE_CLASS;
120 }
121 memcpy(&new_str[idx], name_str, len * sizeof(char));
122 idx += len;
123 if (element_klass->is_instance_klass()) {
124 new_str[idx++] = JVM_SIGNATURE_ENDCLASS;
125 }
126 new_str[idx++] = '\0';
127 return SymbolTable::new_symbol(new_str);
128 }
129
130 // Initialization of vtables and mirror object is done separately from base_create_array_klass,
131 // since a GC can happen. At this point all instance variables of the ArrayKlass must be setup.
132 void ArrayKlass::complete_create_array_klass(ArrayKlass* k, Klass* super_klass, ModuleEntry* module_entry, TRAPS) {
133 k->initialize_supers(super_klass, nullptr, CHECK);
134 k->vtable().initialize_vtable();
135
136 // During bootstrapping, before java.base is defined, the module_entry may not be present yet.
137 // These classes will be put on a fixup list and their module fields will be patched once
138 // java.base is defined.
139 assert((module_entry != nullptr) || ((module_entry == nullptr) && !ModuleEntryTable::javabase_defined()),
140 "module entry not available post " JAVA_BASE_NAME " definition");
141 oop module = (module_entry != nullptr) ? module_entry->module() : (oop)nullptr;
142 java_lang_Class::create_mirror(k, Handle(THREAD, k->class_loader()), Handle(THREAD, module), Handle(), Handle(), CHECK);
143 }
144
145 ArrayKlass* ArrayKlass::array_klass(int n, TRAPS) {
146
147 assert(dimension() <= n, "check order of chain");
148 int dim = dimension();
149 if (dim == n) return this;
150
151 // lock-free read needs acquire semantics
152 if (higher_dimension_acquire() == nullptr) {
153
154 // Ensure atomic creation of higher dimensions
155 RecursiveLocker rl(MultiArray_lock, THREAD);
156
157 if (higher_dimension() == nullptr) {
158 // Create multi-dim klass object and link them together
159 ObjArrayKlass* ak =
160 ObjArrayKlass::allocate_objArray_klass(class_loader_data(), dim + 1, this, false, CHECK_NULL);
161 // use 'release' to pair with lock-free load
162 release_set_higher_dimension(ak);
163 assert(ak->lower_dimension() == this, "lower dimension mismatch");
164 }
165 }
166
167 ObjArrayKlass* ak = higher_dimension();
168 assert(ak != nullptr, "should be set");
169 THREAD->check_possible_safepoint();
170 return ak->array_klass(n, THREAD);
171 }
172
173 ArrayKlass* ArrayKlass::array_klass_or_null(int n) {
174
175 assert(dimension() <= n, "check order of chain");
176 int dim = dimension();
177 if (dim == n) return this;
178
179 // lock-free read needs acquire semantics
180 if (higher_dimension_acquire() == nullptr) {
181 return nullptr;
182 }
183
184 ObjArrayKlass *ak = higher_dimension();
185 return ak->array_klass_or_null(n);
186 }
187
188 ArrayKlass* ArrayKlass::array_klass(TRAPS) {
189 return array_klass(dimension() + 1, THREAD);
190 }
191
192 ArrayKlass* ArrayKlass::array_klass_or_null() {
193 return array_klass_or_null(dimension() + 1);
194 }
195
196
197 GrowableArray<Klass*>* ArrayKlass::compute_secondary_supers(int num_extra_slots,
198 Array<InstanceKlass*>* transitive_interfaces) {
199 // interfaces = { cloneable_klass, serializable_klass };
200 assert(num_extra_slots == 0, "sanity of primitive array type");
201 assert(transitive_interfaces == nullptr, "sanity");
202 // Must share this for correct bootstrapping!
203 set_secondary_supers(Universe::the_array_interfaces_array(),
204 Universe::the_array_interfaces_bitmap());
205 return nullptr;
206 }
207
208 objArrayOop ArrayKlass::allocate_arrayArray(int n, int length, TRAPS) {
209 check_array_allocation_length(length, arrayOopDesc::max_array_length(T_ARRAY), CHECK_NULL);
210 size_t size = objArrayOopDesc::object_size(length);
211 ArrayKlass* ak = array_klass(n + dimension(), CHECK_NULL);
212 objArrayOop o = (objArrayOop)Universe::heap()->array_allocate(ak, size, length,
213 /* do_zero */ true, CHECK_NULL);
214 // initialization to null not necessary, area already cleared
215 return o;
216 }
217
218 oop ArrayKlass::component_mirror() const {
219 return java_lang_Class::component_mirror(java_mirror());
220 }
221
222 jint ArrayKlass::compute_modifier_flags() const {
223 int identity_flag = (Arguments::enable_preview()) ? JVM_ACC_IDENTITY : 0;
224
225 return JVM_ACC_ABSTRACT | JVM_ACC_FINAL | JVM_ACC_PUBLIC
226 | identity_flag;
227 }
228
229 // JVMTI support
230
231 jint ArrayKlass::jvmti_class_status() const {
232 return JVMTI_CLASS_STATUS_ARRAY;
233 }
234
235 void ArrayKlass::metaspace_pointers_do(MetaspaceClosure* it) {
236 Klass::metaspace_pointers_do(it);
237
238 ResourceMark rm;
239 log_trace(cds)("Iter(ArrayKlass): %p (%s)", this, external_name());
240
241 // need to cast away volatile
242 it->push((Klass**)&_higher_dimension);
243 it->push((Klass**)&_lower_dimension);
244 }
245
246 #if INCLUDE_CDS
247 void ArrayKlass::remove_unshareable_info() {
248 Klass::remove_unshareable_info();
249 if (_higher_dimension != nullptr) {
250 ArrayKlass *ak = higher_dimension();
251 ak->remove_unshareable_info();
252 }
253 }
254
255 void ArrayKlass::remove_java_mirror() {
256 Klass::remove_java_mirror();
257 if (_higher_dimension != nullptr) {
258 ArrayKlass *ak = higher_dimension();
259 ak->remove_java_mirror();
260 }
261 }
262
263 void ArrayKlass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) {
264 Klass::restore_unshareable_info(loader_data, protection_domain, CHECK);
265 // Klass recreates the component mirror also
266
267 if (_higher_dimension != nullptr) {
268 ArrayKlass *ak = higher_dimension();
269 log_array_class_load(ak);
270 ak->restore_unshareable_info(loader_data, protection_domain, CHECK);
271 }
272 }
273
274 void ArrayKlass::cds_print_value_on(outputStream* st) const {
275 assert(is_klass(), "must be klass");
276 st->print(" - array: %s", internal_name());
277 if (_higher_dimension != nullptr) {
278 ArrayKlass* ak = higher_dimension();
279 st->cr();
280 ak->cds_print_value_on(st);
281 }
282 }
283 #endif // INCLUDE_CDS
284
285 void ArrayKlass::log_array_class_load(Klass* k) {
286 LogTarget(Debug, class, load, array) lt;
287 if (lt.is_enabled()) {
288 LogStream ls(lt);
289 ResourceMark rm;
290 ls.print("%s", k->name()->as_klass_external_name());
291 if (MetaspaceShared::is_shared_dynamic((void*)k)) {
292 ls.print(" source: shared objects file (top)");
293 } else if (MetaspaceShared::is_shared_static((void*)k)) {
294 ls.print(" source: shared objects file");
295 }
296 ls.cr();
297 }
298 }
299
300 // Printing
301
302 void ArrayKlass::print_on(outputStream* st) const {
303 assert(is_klass(), "must be klass");
304 Klass::print_on(st);
305 }
306
307 void ArrayKlass::print_value_on(outputStream* st) const {
308 assert(is_klass(), "must be klass");
309 for(int index = 0; index < dimension(); index++) {
310 st->print("[]");
311 }
312 }
313
314 void ArrayKlass::oop_print_on(oop obj, outputStream* st) {
315 assert(obj->is_array(), "must be array");
316 Klass::oop_print_on(obj, st);
317 st->print_cr(" - length: %d", arrayOop(obj)->length());
318 }
319
320
321 // Verification
322
323 void ArrayKlass::verify_on(outputStream* st) {
324 Klass::verify_on(st);
325 }
326
327 void ArrayKlass::oop_verify_on(oop obj, outputStream* st) {
328 guarantee(obj->is_array(), "must be array");
329 arrayOop a = arrayOop(obj);
330 guarantee(a->length() >= 0, "array with negative length?");
331 }