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/cdsConfig.hpp"
26 #include "classfile/moduleEntry.hpp"
27 #include "classfile/packageEntry.hpp"
28 #include "classfile/symbolTable.hpp"
29 #include "classfile/vmClasses.hpp"
30 #include "classfile/vmSymbols.hpp"
31 #include "gc/shared/collectedHeap.inline.hpp"
32 #include "memory/iterator.inline.hpp"
33 #include "memory/metadataFactory.hpp"
34 #include "memory/metaspaceClosure.hpp"
35 #include "memory/oopFactory.hpp"
36 #include "memory/resourceArea.hpp"
37 #include "memory/universe.hpp"
38 #include "oops/arrayKlass.hpp"
39 #include "oops/flatArrayKlass.hpp"
40 #include "oops/instanceKlass.hpp"
41 #include "oops/klass.inline.hpp"
42 #include "oops/markWord.hpp"
43 #include "oops/objArrayKlass.inline.hpp"
44 #include "oops/objArrayOop.inline.hpp"
45 #include "oops/oop.inline.hpp"
46 #include "oops/refArrayKlass.hpp"
47 #include "oops/symbol.hpp"
48 #include "runtime/arguments.hpp"
49 #include "runtime/handles.inline.hpp"
50 #include "runtime/mutexLocker.hpp"
51 #include "utilities/macros.hpp"
52
53 ObjArrayKlass* ObjArrayKlass::allocate_klass(ClassLoaderData* loader_data, int n,
54 Klass* k, Symbol* name, ArrayKlass::ArrayProperties props,
55 TRAPS) {
56 assert(ObjArrayKlass::header_size() <= InstanceKlass::header_size(),
57 "array klasses must be same size as InstanceKlass");
58
59 int size = ArrayKlass::static_size(ObjArrayKlass::header_size());
60
61 return new (loader_data, size, THREAD) ObjArrayKlass(n, k, name, Kind, props, ArrayKlass::is_null_restricted(props) ? markWord::null_free_array_prototype() : markWord::prototype());
62 }
63
64 ObjArrayKlass* ObjArrayKlass::allocate_objArray_klass(ClassLoaderData* loader_data,
65 int n, Klass* element_klass, TRAPS) {
66
67 // Eagerly allocate the direct array supertype.
68 Klass* super_klass = nullptr;
69 if (!Universe::is_bootstrapping() || vmClasses::Object_klass_loaded()) {
70 assert(MultiArray_lock->holds_lock(THREAD), "must hold lock after bootstrapping");
71 Klass* element_super = element_klass->super();
72 if (element_super != nullptr) {
73 // The element type has a direct super. E.g., String[] has direct super of Object[].
74 // Also, see if the element has secondary supertypes.
75 // We need an array type for each before creating this array type.
76 super_klass = element_super->array_klass(CHECK_NULL);
77 const Array<Klass*>* element_supers = element_klass->secondary_supers();
78 for (int i = element_supers->length() - 1; i >= 0; i--) {
79 Klass* elem_super = element_supers->at(i);
80 elem_super->array_klass(CHECK_NULL);
81 }
82 // Fall through because inheritance is acyclic and we hold the global recursive lock to allocate all the arrays.
83 } else {
84 // The element type is already Object. Object[] has direct super of Object.
85 super_klass = vmClasses::Object_klass();
86 }
87 }
88
89 // Create type name for klass.
90 Symbol* name = ArrayKlass::create_element_klass_array_name(element_klass, CHECK_NULL);
91
92 // Initialize instance variables
93 ObjArrayKlass* oak = ObjArrayKlass::allocate_klass(loader_data, n, element_klass, name, ArrayProperties::INVALID, CHECK_NULL);
94
95 ModuleEntry* module = oak->module();
96 assert(module != nullptr, "No module entry for array");
97
98 // Call complete_create_array_klass after all instance variables has been initialized.
99 ArrayKlass::complete_create_array_klass(oak, super_klass, module, CHECK_NULL);
100
101 // Add all classes to our internal class loader list here,
102 // including classes in the bootstrap (null) class loader.
103 // Do this step after creating the mirror so that if the
104 // mirror creation fails, loaded_classes_do() doesn't find
105 // an array class without a mirror.
106 loader_data->add_class(oak);
107
108 return oak;
109 }
110
111 ObjArrayKlass::ObjArrayKlass(int n, Klass* element_klass, Symbol* name, KlassKind kind, ArrayKlass::ArrayProperties props, markWord mk) :
112 ArrayKlass(name, kind, props, mk) {
113 set_dimension(n);
114 set_element_klass(element_klass);
115 set_next_refined_klass_klass(nullptr);
116 set_properties(props);
117
118 Klass* bk;
119 if (element_klass->is_objArray_klass()) {
120 bk = ObjArrayKlass::cast(element_klass)->bottom_klass();
121 } else {
122 assert(!element_klass->is_refArray_klass(), "Sanity");
123 bk = element_klass;
124 }
125 assert(bk != nullptr && (bk->is_instance_klass() || bk->is_typeArray_klass()), "invalid bottom klass");
126 set_bottom_klass(bk);
127 set_class_loader_data(bk->class_loader_data());
128
129 if (element_klass->is_array_klass()) {
130 set_lower_dimension(ArrayKlass::cast(element_klass));
131 }
132
133 int lh = array_layout_helper(T_OBJECT);
134 if (ArrayKlass::is_null_restricted(props)) {
135 assert(n == 1, "Bytecode does not support null-free multi-dim");
136 lh = layout_helper_set_null_free(lh);
137 #ifdef _LP64
138 assert(prototype_header().is_null_free_array(), "sanity");
139 #endif
140 }
141 set_layout_helper(lh);
142 assert(is_array_klass(), "sanity");
143 assert(is_objArray_klass(), "sanity");
144 }
145
146 size_t ObjArrayKlass::oop_size(oop obj) const {
147 // In this assert, we cannot safely access the Klass* with compact headers,
148 // because size_given_klass() calls oop_size() on objects that might be
149 // concurrently forwarded, which would overwrite the Klass*.
150 assert(UseCompactObjectHeaders || obj->is_objArray(), "must be object array");
151 // return objArrayOop(obj)->object_size();
152 return obj->is_flatArray() ? flatArrayOop(obj)->object_size(layout_helper()) : refArrayOop(obj)->object_size();
153 }
154
155 ArrayDescription ObjArrayKlass::array_layout_selection(Klass* element, ArrayProperties properties) {
156 // TODO FIXME: the layout selection should take the array size in consideration
157 // to avoid creation of arrays too big to be handled by the VM. See JDK-8233189
158 if (!UseArrayFlattening || element->is_array_klass() || element->is_identity_class() || element->is_abstract()) {
159 return ArrayDescription(RefArrayKlassKind, properties, LayoutKind::REFERENCE);
160 }
161 assert(element->is_final(), "Flat layouts below require monomorphic elements");
162 InlineKlass* vk = InlineKlass::cast(element);
163 if (is_null_restricted(properties)) {
164 if (is_non_atomic(properties)) {
165 // Null-restricted + non-atomic
166 if (vk->maybe_flat_in_array() && vk->has_non_atomic_layout()) {
167 return ArrayDescription(FlatArrayKlassKind, properties, LayoutKind::NON_ATOMIC_FLAT);
168 } else {
169 return ArrayDescription(RefArrayKlassKind, properties, LayoutKind::REFERENCE);
170 }
171 } else {
172 // Null-restricted + atomic
173 if (vk->maybe_flat_in_array() && vk->is_naturally_atomic() && vk->has_non_atomic_layout()) {
174 return ArrayDescription(FlatArrayKlassKind, properties, LayoutKind::NON_ATOMIC_FLAT);
175 } else if (vk->maybe_flat_in_array() && vk->has_atomic_layout()) {
176 return ArrayDescription(FlatArrayKlassKind, properties, LayoutKind::ATOMIC_FLAT);
177 } else {
178 return ArrayDescription(RefArrayKlassKind, properties, LayoutKind::REFERENCE);
179 }
180 }
181 } else {
182 // nullable implies atomic, so the non-atomic property is ignored
183 if (vk->maybe_flat_in_array() && vk->has_nullable_atomic_layout()) {
184 return ArrayDescription(FlatArrayKlassKind, properties, LayoutKind::NULLABLE_ATOMIC_FLAT);
185 } else {
186 return ArrayDescription(RefArrayKlassKind, properties, LayoutKind::REFERENCE);
187 }
188 }
189 }
190
191 objArrayOop ObjArrayKlass::allocate_instance(int length, ArrayProperties props, TRAPS) {
192 check_array_allocation_length(length, arrayOopDesc::max_array_length(T_OBJECT), CHECK_NULL);
193 ObjArrayKlass* ak = klass_with_properties(props, THREAD);
194 size_t size = 0;
195 switch(ak->kind()) {
196 case Klass::RefArrayKlassKind:
197 size = refArrayOopDesc::object_size(length);
198 break;
199 case Klass::FlatArrayKlassKind:
200 size = flatArrayOopDesc::object_size(ak->layout_helper(), length);
201 break;
202 default:
203 ShouldNotReachHere();
204 }
205 assert(size != 0, "Sanity check");
206 objArrayOop array = (objArrayOop)Universe::heap()->array_allocate(
207 ak, size, length,
208 /* do_zero */ true, CHECK_NULL);
209 assert(array->is_refArray() || array->is_flatArray(), "Must be");
210 objArrayHandle array_h(THREAD, array);
211 return array_h();
212 }
213
214 oop ObjArrayKlass::multi_allocate(int rank, jint* sizes, TRAPS) {
215 int length = *sizes;
216 ArrayKlass* ld_klass = lower_dimension();
217 // If length < 0 allocate will throw an exception.
218 ObjArrayKlass* oak = klass_with_properties(ArrayProperties::DEFAULT, CHECK_NULL);
219 assert(oak->is_refArray_klass() || oak->is_flatArray_klass(), "Must be");
220 objArrayOop array = oak->allocate_instance(length, ArrayProperties::DEFAULT, CHECK_NULL);
221 objArrayHandle h_array (THREAD, array);
222 if (rank > 1) {
223 if (length != 0) {
224 for (int index = 0; index < length; index++) {
225 oop sub_array = ld_klass->multi_allocate(rank-1, &sizes[1], CHECK_NULL);
226 h_array->obj_at_put(index, sub_array);
227 }
228 } else {
229 // Since this array dimension has zero length, nothing will be
230 // allocated, however the lower dimension values must be checked
231 // for illegal values.
232 for (int i = 0; i < rank - 1; ++i) {
233 sizes += 1;
234 if (*sizes < 0) {
235 THROW_MSG_NULL(vmSymbols::java_lang_NegativeArraySizeException(), err_msg("%d", *sizes));
236 }
237 }
238 }
239 }
240 return h_array();
241 }
242
243 void ObjArrayKlass::copy_array(arrayOop s, int src_pos, arrayOop d,
244 int dst_pos, int length, TRAPS) {
245 assert(s->is_objArray(), "must be obj array");
246
247 if (UseArrayFlattening) {
248 if (d->is_flatArray()) {
249 FlatArrayKlass::cast(d->klass())->copy_array(s, src_pos, d, dst_pos, length, THREAD);
250 return;
251 }
252 if (s->is_flatArray()) {
253 FlatArrayKlass::cast(s->klass())->copy_array(s, src_pos, d, dst_pos, length, THREAD);
254 return;
255 }
256 }
257
258 assert(s->is_refArray() && d->is_refArray(), "Must be");
259 RefArrayKlass::cast(s->klass())->copy_array(s, src_pos, d, dst_pos, length, THREAD);
260 }
261
262 bool ObjArrayKlass::can_be_primary_super_slow() const {
263 if (!bottom_klass()->can_be_primary_super())
264 // array of interfaces
265 return false;
266 else
267 return Klass::can_be_primary_super_slow();
268 }
269
270 GrowableArray<Klass*>* ObjArrayKlass::compute_secondary_supers(int num_extra_slots,
271 Array<InstanceKlass*>* transitive_interfaces) {
272 assert(transitive_interfaces == nullptr, "sanity");
273 // interfaces = { cloneable_klass, serializable_klass, elemSuper[], ... };
274 const Array<Klass*>* elem_supers = element_klass()->secondary_supers();
275 int num_elem_supers = elem_supers == nullptr ? 0 : elem_supers->length();
276 int num_secondaries = num_extra_slots + 2 + num_elem_supers;
277 if (num_secondaries == 2) {
278 // Must share this for correct bootstrapping!
279 set_secondary_supers(Universe::the_array_interfaces_array(),
280 Universe::the_array_interfaces_bitmap());
281 return nullptr;
282 } else {
283 GrowableArray<Klass*>* secondaries = new GrowableArray<Klass*>(num_elem_supers+2);
284 secondaries->push(vmClasses::Cloneable_klass());
285 secondaries->push(vmClasses::Serializable_klass());
286 for (int i = 0; i < num_elem_supers; i++) {
287 Klass* elem_super = elem_supers->at(i);
288 Klass* array_super = elem_super->array_klass_or_null();
289 assert(array_super != nullptr, "must already have been created");
290 secondaries->push(array_super);
291 }
292 return secondaries;
293 }
294 }
295
296 void ObjArrayKlass::initialize(TRAPS) {
297 bottom_klass()->initialize(THREAD); // dispatches to either InstanceKlass or TypeArrayKlass
298 }
299
300 void ObjArrayKlass::metaspace_pointers_do(MetaspaceClosure* it) {
301 ArrayKlass::metaspace_pointers_do(it);
302 it->push(&_element_klass);
303 it->push(&_bottom_klass);
304 if (_next_refined_array_klass != nullptr && !CDSConfig::is_dumping_dynamic_archive()) {
305 it->push(&_next_refined_array_klass);
306 }
307 }
308
309 void ObjArrayKlass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) {
310 ArrayKlass::restore_unshareable_info(loader_data, protection_domain, CHECK);
311 if (_next_refined_array_klass != nullptr) {
312 _next_refined_array_klass->restore_unshareable_info(loader_data, protection_domain, CHECK);
313 }
314 }
315
316 void ObjArrayKlass::remove_unshareable_info() {
317 ArrayKlass::remove_unshareable_info();
318 if (_next_refined_array_klass != nullptr && !CDSConfig::is_dumping_dynamic_archive()) {
319 _next_refined_array_klass->remove_unshareable_info();
320 } else {
321 _next_refined_array_klass = nullptr;
322 }
323 }
324
325 void ObjArrayKlass::remove_java_mirror() {
326 ArrayKlass::remove_java_mirror();
327 if (_next_refined_array_klass != nullptr) {
328 _next_refined_array_klass->remove_java_mirror();
329 }
330 }
331
332 u2 ObjArrayKlass::compute_modifier_flags() const {
333 // The modifier for an objectArray is the same as its element
334 assert (element_klass() != nullptr, "should be initialized");
335
336 // Return the flags of the bottom element type.
337 u2 element_flags = bottom_klass()->compute_modifier_flags();
338
339 int identity_flag = (Arguments::enable_preview()) ? JVM_ACC_IDENTITY : 0;
340
341 return (element_flags & (JVM_ACC_PUBLIC | JVM_ACC_PRIVATE | JVM_ACC_PROTECTED))
342 | (identity_flag | JVM_ACC_ABSTRACT | JVM_ACC_FINAL);
343 }
344
345 ModuleEntry* ObjArrayKlass::module() const {
346 assert(bottom_klass() != nullptr, "ObjArrayKlass returned unexpected null bottom_klass");
347 // The array is defined in the module of its bottom class
348 return bottom_klass()->module();
349 }
350
351 PackageEntry* ObjArrayKlass::package() const {
352 assert(bottom_klass() != nullptr, "ObjArrayKlass returned unexpected null bottom_klass");
353 return bottom_klass()->package();
354 }
355
356 ObjArrayKlass* ObjArrayKlass::klass_with_properties(ArrayKlass::ArrayProperties props, TRAPS) {
357 assert(props != ArrayProperties::INVALID, "Sanity check");
358
359 if (properties() == props) {
360 assert(is_refArray_klass() || is_flatArray_klass(), "Must be a concrete array klass");
361 return this;
362 }
363
364 ObjArrayKlass* ak = next_refined_array_klass_acquire();
365 if (ak == nullptr) {
366 // Ensure atomic creation of refined array klasses
367 RecursiveLocker rl(MultiArray_lock, THREAD);
368
369 if (next_refined_array_klass() == nullptr) {
370 ArrayDescription ad = ObjArrayKlass::array_layout_selection(element_klass(), props);
371 switch (ad._kind) {
372 case Klass::RefArrayKlassKind: {
373 ak = RefArrayKlass::allocate_refArray_klass(class_loader_data(), dimension(), element_klass(), props, CHECK_NULL);
374 break;
375 }
376 case Klass::FlatArrayKlassKind: {
377 assert(dimension() == 1, "Flat arrays can only be dimension 1 arrays");
378 ak = FlatArrayKlass::allocate_klass(element_klass(), props, ad._layout_kind, CHECK_NULL);
379 break;
380 }
381 default:
382 ShouldNotReachHere();
383 }
384 release_set_next_refined_klass(ak);
385 }
386 }
387
388 ak = next_refined_array_klass();
389 assert(ak != nullptr, "should be set");
390 THREAD->check_possible_safepoint();
391 return ak->klass_with_properties(props, THREAD); // why not CHECK_NULL ?
392 }
393
394
395 // Printing
396
397 void ObjArrayKlass::print_on(outputStream* st) const {
398 #ifndef PRODUCT
399 Klass::print_on(st);
400 st->print(" - element klass: ");
401 element_klass()->print_value_on(st);
402 st->cr();
403 #endif //PRODUCT
404 }
405
406 void ObjArrayKlass::print_value_on(outputStream* st) const {
407 assert(is_klass(), "must be klass");
408
409 element_klass()->print_value_on(st);
410 st->print("[]");
411 }
412
413 #ifndef PRODUCT
414
415 void ObjArrayKlass::oop_print_on(oop obj, outputStream* st) {
416 ShouldNotReachHere();
417 }
418
419 #endif //PRODUCT
420
421 void ObjArrayKlass::oop_print_value_on(oop obj, outputStream* st) {
422 ShouldNotReachHere();
423 }
424
425 const char* ObjArrayKlass::internal_name() const {
426 return external_name();
427 }
428
429
430 // Verification
431
432 void ObjArrayKlass::verify_on(outputStream* st) {
433 ArrayKlass::verify_on(st);
434 guarantee(element_klass()->is_klass(), "should be klass");
435 guarantee(bottom_klass()->is_klass(), "should be klass");
436 Klass* bk = bottom_klass();
437 guarantee(bk->is_instance_klass() || bk->is_typeArray_klass() || bk->is_flatArray_klass(),
438 "invalid bottom klass");
439 }
440
441 void ObjArrayKlass::oop_verify_on(oop obj, outputStream* st) {
442 ArrayKlass::oop_verify_on(obj, st);
443 guarantee(obj->is_objArray(), "must be objArray");
444 guarantee(obj->is_null_free_array() || (!is_null_free_array_klass()), "null-free klass but not object");
445 objArrayOop oa = objArrayOop(obj);
446 for(int index = 0; index < oa->length(); index++) {
447 guarantee(oopDesc::is_oop_or_null(oa->obj_at(index)), "should be oop");
448 }
449 }