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 Symbol* ObjArrayKlass::create_element_klass_array_name(JavaThread* current, Klass* element_klass) {
65 ResourceMark rm(current);
66 char* name_str = element_klass->name()->as_C_string();
67 int len = element_klass->name()->utf8_length();
68 char* new_str = NEW_RESOURCE_ARRAY_IN_THREAD(current, char, len + 4);
69 int idx = 0;
70 new_str[idx++] = JVM_SIGNATURE_ARRAY;
71 if (element_klass->is_instance_klass()) { // it could be an array or simple type
72 new_str[idx++] = JVM_SIGNATURE_CLASS;
73 }
74 memcpy(&new_str[idx], name_str, len * sizeof(char));
75 idx += len;
76 if (element_klass->is_instance_klass()) {
77 new_str[idx++] = JVM_SIGNATURE_ENDCLASS;
78 }
79 new_str[idx] = '\0';
80 return SymbolTable::new_symbol(new_str);
81 }
82
83
84 ObjArrayKlass* ObjArrayKlass::allocate_objArray_klass(ClassLoaderData* loader_data,
85 int n, Klass* element_klass, TRAPS) {
86
87 // Eagerly allocate the direct array supertype.
88 Klass* super_klass = nullptr;
89 if (!Universe::is_bootstrapping() || vmClasses::Object_klass_loaded()) {
90 assert(MultiArray_lock->holds_lock(THREAD), "must hold lock after bootstrapping");
91 Klass* element_super = element_klass->super();
92 if (element_super != nullptr) {
93 // The element type has a direct super. E.g., String[] has direct super of Object[].
94 // Also, see if the element has secondary supertypes.
95 // We need an array type for each before creating this array type.
96 super_klass = element_super->array_klass(CHECK_NULL);
97 const Array<Klass*>* element_supers = element_klass->secondary_supers();
98 for (int i = element_supers->length() - 1; i >= 0; i--) {
99 Klass* elem_super = element_supers->at(i);
100 elem_super->array_klass(CHECK_NULL);
101 }
102 // Fall through because inheritance is acyclic and we hold the global recursive lock to allocate all the arrays.
103 } else {
104 // The element type is already Object. Object[] has direct super of Object.
105 super_klass = vmClasses::Object_klass();
106 }
107 }
108
109 // Create type name for klass.
110 Symbol* name = create_element_klass_array_name(THREAD, element_klass);
111
112 // Initialize instance variables
113 ObjArrayKlass* oak = ObjArrayKlass::allocate_klass(loader_data, n, element_klass, name, ArrayProperties::INVALID, CHECK_NULL);
114
115 ModuleEntry* module = oak->module();
116 assert(module != nullptr, "No module entry for array");
117
118 // Call complete_create_array_klass after all instance variables has been initialized.
119 ArrayKlass::complete_create_array_klass(oak, super_klass, module, CHECK_NULL);
120
121 // Add all classes to our internal class loader list here,
122 // including classes in the bootstrap (null) class loader.
123 // Do this step after creating the mirror so that if the
124 // mirror creation fails, loaded_classes_do() doesn't find
125 // an array class without a mirror.
126 loader_data->add_class(oak);
127
128 return oak;
129 }
130
131 ObjArrayKlass::ObjArrayKlass(int n, Klass* element_klass, Symbol* name, KlassKind kind, ArrayKlass::ArrayProperties props, markWord mk) :
132 ArrayKlass(name, kind, props, mk) {
133 set_dimension(n);
134 set_element_klass(element_klass);
135 set_next_refined_klass_klass(nullptr);
136 set_properties(props);
137
138 Klass* bk;
139 if (element_klass->is_objArray_klass()) {
140 bk = ObjArrayKlass::cast(element_klass)->bottom_klass();
141 } else {
142 assert(!element_klass->is_refArray_klass(), "Sanity");
143 bk = element_klass;
144 }
145 assert(bk != nullptr && (bk->is_instance_klass() || bk->is_typeArray_klass()), "invalid bottom klass");
146 set_bottom_klass(bk);
147 set_class_loader_data(bk->class_loader_data());
148
149 if (element_klass->is_array_klass()) {
150 set_lower_dimension(ArrayKlass::cast(element_klass));
151 }
152
153 int lh = array_layout_helper(T_OBJECT);
154 if (ArrayKlass::is_null_restricted(props)) {
155 assert(n == 1, "Bytecode does not support null-free multi-dim");
156 lh = layout_helper_set_null_free(lh);
157 #ifdef _LP64
158 assert(prototype_header().is_null_free_array(), "sanity");
159 #endif
160 }
161 set_layout_helper(lh);
162 assert(is_array_klass(), "sanity");
163 assert(is_objArray_klass(), "sanity");
164 }
165
166 size_t ObjArrayKlass::oop_size(oop obj) const {
167 // In this assert, we cannot safely access the Klass* with compact headers,
168 // because size_given_klass() calls oop_size() on objects that might be
169 // concurrently forwarded, which would overwrite the Klass*.
170 assert(UseCompactObjectHeaders || obj->is_objArray(), "must be object array");
171 // return objArrayOop(obj)->object_size();
172 return obj->is_flatArray() ? flatArrayOop(obj)->object_size(layout_helper()) : refArrayOop(obj)->object_size();
173 }
174
175 ArrayDescription ObjArrayKlass::array_layout_selection(Klass* element, ArrayProperties properties) {
176 // TODO FIXME: the layout selection should take the array size in consideration
177 // to avoid creation of arrays too big to be handled by the VM. See JDK-8233189
178 if (!UseArrayFlattening || element->is_array_klass() || element->is_identity_class() || element->is_abstract()) {
179 return ArrayDescription(RefArrayKlassKind, properties, LayoutKind::REFERENCE);
180 }
181 assert(element->is_final(), "Flat layouts below require monomorphic elements");
182 InlineKlass* vk = InlineKlass::cast(element);
183 if (is_null_restricted(properties)) {
184 if (is_non_atomic(properties)) {
185 // Null-restricted + non-atomic
186 if (vk->maybe_flat_in_array() && vk->has_non_atomic_layout()) {
187 return ArrayDescription(FlatArrayKlassKind, properties, LayoutKind::NON_ATOMIC_FLAT);
188 } else {
189 return ArrayDescription(RefArrayKlassKind, properties, LayoutKind::REFERENCE);
190 }
191 } else {
192 // Null-restricted + atomic
193 if (vk->maybe_flat_in_array() && vk->is_naturally_atomic() && vk->has_non_atomic_layout()) {
194 return ArrayDescription(FlatArrayKlassKind, properties, LayoutKind::NON_ATOMIC_FLAT);
195 } else if (vk->maybe_flat_in_array() && vk->has_atomic_layout()) {
196 return ArrayDescription(FlatArrayKlassKind, properties, LayoutKind::ATOMIC_FLAT);
197 } else {
198 return ArrayDescription(RefArrayKlassKind, properties, LayoutKind::REFERENCE);
199 }
200 }
201 } else {
202 // nullable implies atomic, so the non-atomic property is ignored
203 if (vk->maybe_flat_in_array() && vk->has_nullable_atomic_layout()) {
204 return ArrayDescription(FlatArrayKlassKind, properties, LayoutKind::NULLABLE_ATOMIC_FLAT);
205 } else {
206 return ArrayDescription(RefArrayKlassKind, properties, LayoutKind::REFERENCE);
207 }
208 }
209 }
210
211 objArrayOop ObjArrayKlass::allocate_instance(int length, ArrayProperties props, TRAPS) {
212 check_array_allocation_length(length, arrayOopDesc::max_array_length(T_OBJECT), CHECK_NULL);
213 ObjArrayKlass* ak = klass_with_properties(props, THREAD);
214 size_t size = 0;
215 switch(ak->kind()) {
216 case Klass::RefArrayKlassKind:
217 size = refArrayOopDesc::object_size(length);
218 break;
219 case Klass::FlatArrayKlassKind:
220 size = flatArrayOopDesc::object_size(ak->layout_helper(), length);
221 break;
222 default:
223 ShouldNotReachHere();
224 }
225 assert(size != 0, "Sanity check");
226 objArrayOop array = (objArrayOop)Universe::heap()->array_allocate(
227 ak, size, length,
228 /* do_zero */ true, CHECK_NULL);
229 assert(array->is_refArray() || array->is_flatArray(), "Must be");
230 objArrayHandle array_h(THREAD, array);
231 return array_h();
232 }
233
234 oop ObjArrayKlass::multi_allocate(int rank, jint* sizes, TRAPS) {
235 int length = *sizes;
236 ArrayKlass* ld_klass = lower_dimension();
237 // If length < 0 allocate will throw an exception.
238 ObjArrayKlass* oak = klass_with_properties(ArrayProperties::DEFAULT, CHECK_NULL);
239 assert(oak->is_refArray_klass() || oak->is_flatArray_klass(), "Must be");
240 objArrayOop array = oak->allocate_instance(length, ArrayProperties::DEFAULT, CHECK_NULL);
241 objArrayHandle h_array (THREAD, array);
242 if (rank > 1) {
243 if (length != 0) {
244 for (int index = 0; index < length; index++) {
245 oop sub_array = ld_klass->multi_allocate(rank-1, &sizes[1], CHECK_NULL);
246 h_array->obj_at_put(index, sub_array);
247 }
248 } else {
249 // Since this array dimension has zero length, nothing will be
250 // allocated, however the lower dimension values must be checked
251 // for illegal values.
252 for (int i = 0; i < rank - 1; ++i) {
253 sizes += 1;
254 if (*sizes < 0) {
255 THROW_MSG_NULL(vmSymbols::java_lang_NegativeArraySizeException(), err_msg("%d", *sizes));
256 }
257 }
258 }
259 }
260 return h_array();
261 }
262
263 void ObjArrayKlass::copy_array(arrayOop s, int src_pos, arrayOop d,
264 int dst_pos, int length, TRAPS) {
265 assert(s->is_objArray(), "must be obj array");
266
267 if (UseArrayFlattening) {
268 if (d->is_flatArray()) {
269 FlatArrayKlass::cast(d->klass())->copy_array(s, src_pos, d, dst_pos, length, THREAD);
270 return;
271 }
272 if (s->is_flatArray()) {
273 FlatArrayKlass::cast(s->klass())->copy_array(s, src_pos, d, dst_pos, length, THREAD);
274 return;
275 }
276 }
277
278 assert(s->is_refArray() && d->is_refArray(), "Must be");
279 RefArrayKlass::cast(s->klass())->copy_array(s, src_pos, d, dst_pos, length, THREAD);
280 }
281
282 bool ObjArrayKlass::can_be_primary_super_slow() const {
283 if (!bottom_klass()->can_be_primary_super())
284 // array of interfaces
285 return false;
286 else
287 return Klass::can_be_primary_super_slow();
288 }
289
290 GrowableArray<Klass*>* ObjArrayKlass::compute_secondary_supers(int num_extra_slots,
291 Array<InstanceKlass*>* transitive_interfaces) {
292 assert(transitive_interfaces == nullptr, "sanity");
293 // interfaces = { cloneable_klass, serializable_klass, elemSuper[], ... };
294 const Array<Klass*>* elem_supers = element_klass()->secondary_supers();
295 int num_elem_supers = elem_supers == nullptr ? 0 : elem_supers->length();
296 int num_secondaries = num_extra_slots + 2 + num_elem_supers;
297 if (num_secondaries == 2) {
298 // Must share this for correct bootstrapping!
299 set_secondary_supers(Universe::the_array_interfaces_array(),
300 Universe::the_array_interfaces_bitmap());
301 return nullptr;
302 } else {
303 GrowableArray<Klass*>* secondaries = new GrowableArray<Klass*>(num_elem_supers+2);
304 secondaries->push(vmClasses::Cloneable_klass());
305 secondaries->push(vmClasses::Serializable_klass());
306 for (int i = 0; i < num_elem_supers; i++) {
307 Klass* elem_super = elem_supers->at(i);
308 Klass* array_super = elem_super->array_klass_or_null();
309 assert(array_super != nullptr, "must already have been created");
310 secondaries->push(array_super);
311 }
312 return secondaries;
313 }
314 }
315
316 void ObjArrayKlass::initialize(TRAPS) {
317 bottom_klass()->initialize(THREAD); // dispatches to either InstanceKlass or TypeArrayKlass
318 }
319
320 void ObjArrayKlass::metaspace_pointers_do(MetaspaceClosure* it) {
321 ArrayKlass::metaspace_pointers_do(it);
322 it->push(&_element_klass);
323 it->push(&_bottom_klass);
324 if (_next_refined_array_klass != nullptr && !CDSConfig::is_dumping_dynamic_archive()) {
325 it->push(&_next_refined_array_klass);
326 }
327 }
328
329 #if INCLUDE_CDS
330 void ObjArrayKlass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) {
331 ArrayKlass::restore_unshareable_info(loader_data, protection_domain, CHECK);
332 if (_next_refined_array_klass != nullptr) {
333 _next_refined_array_klass->restore_unshareable_info(loader_data, protection_domain, CHECK);
334 }
335 }
336
337 void ObjArrayKlass::remove_unshareable_info() {
338 ArrayKlass::remove_unshareable_info();
339 if (_next_refined_array_klass != nullptr && !CDSConfig::is_dumping_dynamic_archive()) {
340 _next_refined_array_klass->remove_unshareable_info();
341 } else {
342 _next_refined_array_klass = nullptr;
343 }
344 }
345
346 void ObjArrayKlass::remove_java_mirror() {
347 ArrayKlass::remove_java_mirror();
348 if (_next_refined_array_klass != nullptr && !CDSConfig::is_dumping_dynamic_archive()) {
349 _next_refined_array_klass->remove_java_mirror();
350 }
351 }
352 #endif // INCLUDE_CDS
353
354 u2 ObjArrayKlass::compute_modifier_flags() const {
355 // The modifier for an objectArray is the same as its element
356 assert (element_klass() != nullptr, "should be initialized");
357
358 // Return the flags of the bottom element type.
359 u2 element_flags = bottom_klass()->compute_modifier_flags();
360
361 int identity_flag = (Arguments::enable_preview()) ? JVM_ACC_IDENTITY : 0;
362
363 return (element_flags & (JVM_ACC_PUBLIC | JVM_ACC_PRIVATE | JVM_ACC_PROTECTED))
364 | (identity_flag | JVM_ACC_ABSTRACT | JVM_ACC_FINAL);
365 }
366
367 ModuleEntry* ObjArrayKlass::module() const {
368 assert(bottom_klass() != nullptr, "ObjArrayKlass returned unexpected null bottom_klass");
369 // The array is defined in the module of its bottom class
370 return bottom_klass()->module();
371 }
372
373 PackageEntry* ObjArrayKlass::package() const {
374 assert(bottom_klass() != nullptr, "ObjArrayKlass returned unexpected null bottom_klass");
375 return bottom_klass()->package();
376 }
377
378 ObjArrayKlass* ObjArrayKlass::klass_with_properties(ArrayKlass::ArrayProperties props, TRAPS) {
379 assert(props != ArrayProperties::INVALID, "Sanity check");
380
381 if (properties() == props) {
382 assert(is_refArray_klass() || is_flatArray_klass(), "Must be a concrete array klass");
383 return this;
384 }
385
386 ObjArrayKlass* ak = next_refined_array_klass_acquire();
387 if (ak == nullptr) {
388 // Ensure atomic creation of refined array klasses
389 RecursiveLocker rl(MultiArray_lock, THREAD);
390
391 if (next_refined_array_klass() == nullptr) {
392 ArrayDescription ad = ObjArrayKlass::array_layout_selection(element_klass(), props);
393 switch (ad._kind) {
394 case Klass::RefArrayKlassKind: {
395 ak = RefArrayKlass::allocate_refArray_klass(class_loader_data(), dimension(), element_klass(), props, CHECK_NULL);
396 break;
397 }
398 case Klass::FlatArrayKlassKind: {
399 assert(dimension() == 1, "Flat arrays can only be dimension 1 arrays");
400 ak = FlatArrayKlass::allocate_klass(element_klass(), props, ad._layout_kind, CHECK_NULL);
401 break;
402 }
403 default:
404 ShouldNotReachHere();
405 }
406 release_set_next_refined_klass(ak);
407 }
408 }
409
410 ak = next_refined_array_klass();
411 assert(ak != nullptr, "should be set");
412 THREAD->check_possible_safepoint();
413 return ak->klass_with_properties(props, THREAD); // why not CHECK_NULL ?
414 }
415
416
417 // Printing
418
419 void ObjArrayKlass::print_on(outputStream* st) const {
420 #ifndef PRODUCT
421 Klass::print_on(st);
422 st->print(" - element klass: ");
423 element_klass()->print_value_on(st);
424 st->cr();
425 #endif //PRODUCT
426 }
427
428 void ObjArrayKlass::print_value_on(outputStream* st) const {
429 assert(is_klass(), "must be klass");
430
431 element_klass()->print_value_on(st);
432 st->print("[]");
433 }
434
435 #ifndef PRODUCT
436
437 void ObjArrayKlass::oop_print_on(oop obj, outputStream* st) {
438 ShouldNotReachHere();
439 }
440
441 #endif //PRODUCT
442
443 void ObjArrayKlass::oop_print_value_on(oop obj, outputStream* st) {
444 ShouldNotReachHere();
445 }
446
447 const char* ObjArrayKlass::internal_name() const {
448 return external_name();
449 }
450
451
452 // Verification
453
454 void ObjArrayKlass::verify_on(outputStream* st) {
455 ArrayKlass::verify_on(st);
456 guarantee(element_klass()->is_klass(), "should be klass");
457 guarantee(bottom_klass()->is_klass(), "should be klass");
458 Klass* bk = bottom_klass();
459 guarantee(bk->is_instance_klass() || bk->is_typeArray_klass() || bk->is_flatArray_klass(),
460 "invalid bottom klass");
461 }
462
463 void ObjArrayKlass::oop_verify_on(oop obj, outputStream* st) {
464 ArrayKlass::oop_verify_on(obj, st);
465 guarantee(obj->is_objArray(), "must be objArray");
466 guarantee(obj->is_null_free_array() || (!is_null_free_array_klass()), "null-free klass but not object");
467 objArrayOop oa = objArrayOop(obj);
468 for(int index = 0; index < oa->length(); index++) {
469 guarantee(oopDesc::is_oop_or_null(oa->obj_at(index)), "should be oop");
470 }
471 }