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/inlineKlass.hpp"
41 #include "oops/instanceKlass.hpp"
42 #include "oops/klass.inline.hpp"
43 #include "oops/layoutKind.hpp"
44 #include "oops/markWord.hpp"
45 #include "oops/objArrayKlass.inline.hpp"
46 #include "oops/objArrayOop.inline.hpp"
47 #include "oops/oop.inline.hpp"
48 #include "oops/refArrayKlass.hpp"
49 #include "oops/symbol.hpp"
50 #include "runtime/arguments.hpp"
51 #include "runtime/handles.inline.hpp"
52 #include "runtime/mutexLocker.hpp"
53 #include "utilities/macros.hpp"
54
55 ObjArrayKlass* ObjArrayKlass::allocate_klass(ClassLoaderData* loader_data, int n,
56 Klass* k, Symbol* name, ArrayKlass::ArrayProperties props,
57 TRAPS) {
58 assert(ObjArrayKlass::header_size() <= InstanceKlass::header_size(),
59 "array klasses must be same size as InstanceKlass");
60
61 int size = ArrayKlass::static_size(ObjArrayKlass::header_size());
62
63 return new (loader_data, size, THREAD) ObjArrayKlass(n, k, name, Kind, props, ArrayKlass::is_null_restricted(props) ? markWord::null_free_array_prototype() : markWord::prototype());
64 }
65
66 Symbol* ObjArrayKlass::create_element_klass_array_name(JavaThread* current, Klass* element_klass) {
67 ResourceMark rm(current);
68 char* name_str = element_klass->name()->as_C_string();
69 int len = element_klass->name()->utf8_length();
70 char* new_str = NEW_RESOURCE_ARRAY_IN_THREAD(current, char, len + 4);
71 int idx = 0;
72 new_str[idx++] = JVM_SIGNATURE_ARRAY;
73 if (element_klass->is_instance_klass()) { // it could be an array or simple type
74 new_str[idx++] = JVM_SIGNATURE_CLASS;
75 }
76 memcpy(&new_str[idx], name_str, len * sizeof(char));
77 idx += len;
78 if (element_klass->is_instance_klass()) {
79 new_str[idx++] = JVM_SIGNATURE_ENDCLASS;
80 }
81 new_str[idx] = '\0';
82 return SymbolTable::new_symbol(new_str);
83 }
84
85
86 ObjArrayKlass* ObjArrayKlass::allocate_objArray_klass(ClassLoaderData* loader_data,
87 int n, Klass* element_klass, TRAPS) {
88
89 // Eagerly allocate the direct array supertype.
90 Klass* super_klass = nullptr;
91 if (!Universe::is_bootstrapping() || vmClasses::Object_klass_is_loaded()) {
92 assert(MultiArray_lock->holds_lock(THREAD), "must hold lock after bootstrapping");
93 Klass* element_super = element_klass->super();
94 if (element_super != nullptr) {
95 // The element type has a direct super. E.g., String[] has direct super of Object[].
96 // Also, see if the element has secondary supertypes.
97 // We need an array type for each before creating this array type.
98 super_klass = element_super->array_klass(CHECK_NULL);
99 const Array<Klass*>* element_supers = element_klass->secondary_supers();
100 for (int i = element_supers->length() - 1; i >= 0; i--) {
101 Klass* elem_super = element_supers->at(i);
102 elem_super->array_klass(CHECK_NULL);
103 }
104 // Fall through because inheritance is acyclic and we hold the global recursive lock to allocate all the arrays.
105 } else {
106 // The element type is already Object. Object[] has direct super of Object.
107 super_klass = vmClasses::Object_klass();
108 }
109 }
110
111 // Create type name for klass.
112 Symbol* name = create_element_klass_array_name(THREAD, element_klass);
113
114 // Initialize instance variables
115 ObjArrayKlass* oak = ObjArrayKlass::allocate_klass(loader_data, n, element_klass, name, ArrayProperties::INVALID, CHECK_NULL);
116
117 ModuleEntry* module = oak->module();
118 assert(module != nullptr, "No module entry for array");
119
120 // Call complete_create_array_klass after all instance variables has been initialized.
121 ArrayKlass::complete_create_array_klass(oak, super_klass, module, CHECK_NULL);
122
123 // Add all classes to our internal class loader list here,
124 // including classes in the bootstrap (null) class loader.
125 // Do this step after creating the mirror so that if the
126 // mirror creation fails, loaded_classes_do() doesn't find
127 // an array class without a mirror.
128 loader_data->add_class(oak);
129
130 return oak;
131 }
132
133 ObjArrayKlass::ObjArrayKlass(int n, Klass* element_klass, Symbol* name, KlassKind kind, ArrayKlass::ArrayProperties props, markWord mk) :
134 ArrayKlass(name, kind, props, mk) {
135 set_dimension(n);
136 set_element_klass(element_klass);
137 set_next_refined_klass_klass(nullptr);
138 set_properties(props);
139
140 Klass* bk;
141 if (element_klass->is_objArray_klass()) {
142 assert(!element_klass->is_refined_objArray_klass(), "no such mechanism yet");
143 bk = ObjArrayKlass::cast(element_klass)->bottom_klass();
144 } else {
145 assert(!element_klass->is_refArray_klass(), "Sanity");
146 bk = element_klass;
147 }
148 assert(bk != nullptr && (bk->is_instance_klass() || bk->is_typeArray_klass()), "invalid bottom klass");
149 set_bottom_klass(bk);
150 set_class_loader_data(bk->class_loader_data());
151
152 if (element_klass->is_array_klass()) {
153 set_lower_dimension(ArrayKlass::cast(element_klass));
154 }
155
156 int lh = array_layout_helper(T_OBJECT);
157 if (ArrayKlass::is_null_restricted(props)) {
158 assert(n == 1, "Bytecode does not support null-free multi-dim");
159 lh = layout_helper_set_null_free(lh);
160 #ifdef _LP64
161 assert(prototype_header().is_null_free_array(), "sanity");
162 #endif
163 }
164 set_layout_helper(lh);
165 assert(is_array_klass(), "sanity");
166 assert(is_objArray_klass(), "sanity");
167 }
168
169 size_t ObjArrayKlass::oop_size(oop obj) const {
170 // In this assert, we cannot safely access the Klass* with compact headers,
171 // because size_given_klass() calls oop_size() on objects that might be
172 // concurrently forwarded, which would overwrite the Klass*.
173 assert(UseCompactObjectHeaders || obj->is_objArray(), "must be object array");
174 // return objArrayOop(obj)->object_size();
175 return obj->is_flatArray() ? flatArrayOop(obj)->object_size(layout_helper()) : refArrayOop(obj)->object_size();
176 }
177
178 ArrayDescription ObjArrayKlass::array_layout_selection(Klass* element, ArrayProperties properties) {
179 // TODO FIXME: the layout selection should take the array size in consideration
180 // to avoid creation of arrays too big to be handled by the VM. See JDK-8233189
181 if (!UseArrayFlattening || element->is_array_klass() || element->is_identity_class() || element->is_abstract()) {
182 return ArrayDescription(RefArrayKlassKind, properties, LayoutKind::REFERENCE);
183 }
184 InlineKlass* vk = InlineKlass::cast(element);
185 if (!vk->maybe_flat_in_array()) {
186 return ArrayDescription(RefArrayKlassKind, properties, LayoutKind::REFERENCE);
187 }
188
189 assert(vk->is_final(), "Flat layouts below require monomorphic elements");
190 if (is_null_restricted(properties)) {
191 if (is_non_atomic(properties)) {
192 // Null-restricted + non-atomic
193 if (vk->has_non_atomic_layout()) {
194 return ArrayDescription(FlatArrayKlassKind, properties, LayoutKind::NULL_FREE_NON_ATOMIC_FLAT);
195 } else if (vk->has_atomic_layout()) {
196 return ArrayDescription(FlatArrayKlassKind, properties, LayoutKind::NULL_FREE_ATOMIC_FLAT);
197 } else {
198 return ArrayDescription(RefArrayKlassKind, properties, LayoutKind::REFERENCE);
199 }
200 } else {
201 // Null-restricted + atomic
202 if (vk->is_naturally_atomic() && vk->has_non_atomic_layout()) {
203 return ArrayDescription(FlatArrayKlassKind, properties, LayoutKind::NULL_FREE_NON_ATOMIC_FLAT);
204 } else if (vk->has_atomic_layout()) {
205 return ArrayDescription(FlatArrayKlassKind, properties, LayoutKind::NULL_FREE_ATOMIC_FLAT);
206 } else {
207 return ArrayDescription(RefArrayKlassKind, properties, LayoutKind::REFERENCE);
208 }
209 }
210 } else {
211 // nullable implies atomic, so the non-atomic property is ignored
212 if (vk->has_nullable_atomic_layout()) {
213 return ArrayDescription(FlatArrayKlassKind, properties, LayoutKind::NULLABLE_ATOMIC_FLAT);
214 } else {
215 return ArrayDescription(RefArrayKlassKind, properties, LayoutKind::REFERENCE);
216 }
217 }
218 }
219
220 ObjArrayKlass* ObjArrayKlass::allocate_klass_with_properties(ArrayKlass::ArrayProperties props, TRAPS) {
221 assert(ArrayKlass::is_null_restricted(props) || !ArrayKlass::is_non_atomic(props), "only null-restricted array can be non-atomic");
222 ObjArrayKlass* ak = nullptr;
223 ArrayDescription ad = ObjArrayKlass::array_layout_selection(element_klass(), props);
224 switch (ad._kind) {
225 case Klass::RefArrayKlassKind: {
226 ak = RefArrayKlass::allocate_refArray_klass(class_loader_data(), dimension(), element_klass(), ad._properties, CHECK_NULL);
227 break;
228 }
229 case Klass::FlatArrayKlassKind: {
230 assert(dimension() == 1, "Flat arrays can only be dimension 1 arrays");
231 ak = FlatArrayKlass::allocate_klass(element_klass(), ad._properties, ad._layout_kind, CHECK_NULL);
232 break;
233 }
234 default:
235 ShouldNotReachHere();
236 }
237 return ak;
238 }
239
240 objArrayOop ObjArrayKlass::allocate_instance(int length, ArrayProperties props, TRAPS) {
241 check_array_allocation_length(length, arrayOopDesc::max_array_length(T_OBJECT), CHECK_NULL);
242 ObjArrayKlass* ak = klass_with_properties(props, THREAD);
243 size_t size = 0;
244 switch(ak->kind()) {
245 case Klass::RefArrayKlassKind:
246 size = refArrayOopDesc::object_size(length);
247 break;
248 case Klass::FlatArrayKlassKind:
249 size = flatArrayOopDesc::object_size(ak->layout_helper(), length);
250 break;
251 default:
252 ShouldNotReachHere();
253 }
254 assert(size != 0, "Sanity check");
255 objArrayOop array = (objArrayOop)Universe::heap()->array_allocate(
256 ak, size, length,
257 /* do_zero */ true, CHECK_NULL);
258 assert(array->is_refArray() || array->is_flatArray(), "Must be");
259 return array;
260 }
261
262 oop ObjArrayKlass::multi_allocate(int rank, jint* sizes, TRAPS) {
263 int length = *sizes;
264 ArrayKlass* ld_klass = lower_dimension();
265 // If length < 0 allocate will throw an exception.
266 ObjArrayKlass* oak = klass_with_properties(ArrayProperties::DEFAULT, CHECK_NULL);
267 assert(oak->is_refArray_klass() || oak->is_flatArray_klass(), "Must be");
268 objArrayOop array = oak->allocate_instance(length, ArrayProperties::DEFAULT, CHECK_NULL);
269 objArrayHandle h_array (THREAD, array);
270 if (rank > 1) {
271 if (length != 0) {
272 for (int index = 0; index < length; index++) {
273 oop sub_array = ld_klass->multi_allocate(rank-1, &sizes[1], CHECK_NULL);
274 h_array->obj_at_put(index, sub_array);
275 }
276 } else {
277 // Since this array dimension has zero length, nothing will be
278 // allocated, however the lower dimension values must be checked
279 // for illegal values.
280 for (int i = 0; i < rank - 1; ++i) {
281 sizes += 1;
282 if (*sizes < 0) {
283 THROW_MSG_NULL(vmSymbols::java_lang_NegativeArraySizeException(), err_msg("%d", *sizes));
284 }
285 }
286 }
287 }
288 return h_array();
289 }
290
291 void ObjArrayKlass::copy_array(arrayOop s, int src_pos, arrayOop d,
292 int dst_pos, int length, TRAPS) {
293 assert(s->is_objArray(), "must be obj array");
294
295 if (UseArrayFlattening) {
296 if (d->is_flatArray()) {
297 FlatArrayKlass::cast(d->klass())->copy_array(s, src_pos, d, dst_pos, length, THREAD);
298 return;
299 }
300 if (s->is_flatArray()) {
301 FlatArrayKlass::cast(s->klass())->copy_array(s, src_pos, d, dst_pos, length, THREAD);
302 return;
303 }
304 }
305
306 assert(s->is_refArray() && d->is_refArray(), "Must be");
307 RefArrayKlass::cast(s->klass())->copy_array(s, src_pos, d, dst_pos, length, THREAD);
308 }
309
310 bool ObjArrayKlass::can_be_primary_super_slow() const {
311 if (!bottom_klass()->can_be_primary_super())
312 // array of interfaces
313 return false;
314 else
315 return Klass::can_be_primary_super_slow();
316 }
317
318 GrowableArray<Klass*>* ObjArrayKlass::compute_secondary_supers(int num_extra_slots,
319 Array<InstanceKlass*>* transitive_interfaces) {
320 assert(transitive_interfaces == nullptr, "sanity");
321 // interfaces = { cloneable_klass, serializable_klass, elemSuper[], ... };
322 const Array<Klass*>* elem_supers = element_klass()->secondary_supers();
323 int num_elem_supers = elem_supers == nullptr ? 0 : elem_supers->length();
324 int num_secondaries = num_extra_slots + 2 + num_elem_supers;
325 if (num_secondaries == 2) {
326 // Must share this for correct bootstrapping!
327 set_secondary_supers(Universe::the_array_interfaces_array(),
328 Universe::the_array_interfaces_bitmap());
329 return nullptr;
330 } else {
331 GrowableArray<Klass*>* secondaries = new GrowableArray<Klass*>(num_elem_supers+2);
332 secondaries->push(vmClasses::Cloneable_klass());
333 secondaries->push(vmClasses::Serializable_klass());
334 for (int i = 0; i < num_elem_supers; i++) {
335 Klass* elem_super = elem_supers->at(i);
336 Klass* array_super = elem_super->array_klass_or_null();
337 assert(array_super != nullptr, "must already have been created");
338 secondaries->push(array_super);
339 }
340 return secondaries;
341 }
342 }
343
344 void ObjArrayKlass::initialize(TRAPS) {
345 bottom_klass()->initialize(THREAD); // dispatches to either InstanceKlass or TypeArrayKlass
346 }
347
348 void ObjArrayKlass::metaspace_pointers_do(MetaspaceClosure* it) {
349 ArrayKlass::metaspace_pointers_do(it);
350 it->push(&_element_klass);
351 it->push(&_bottom_klass);
352 if (_next_refined_array_klass != nullptr && !CDSConfig::is_dumping_dynamic_archive()) {
353 it->push(&_next_refined_array_klass);
354 }
355 }
356
357 #if INCLUDE_CDS
358 void ObjArrayKlass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) {
359 ArrayKlass::restore_unshareable_info(loader_data, protection_domain, CHECK);
360 if (_next_refined_array_klass != nullptr) {
361 _next_refined_array_klass->restore_unshareable_info(loader_data, protection_domain, CHECK);
362 }
363 }
364
365 void ObjArrayKlass::remove_unshareable_info() {
366 ArrayKlass::remove_unshareable_info();
367 if (_next_refined_array_klass != nullptr && !CDSConfig::is_dumping_dynamic_archive()) {
368 _next_refined_array_klass->remove_unshareable_info();
369 } else {
370 _next_refined_array_klass = nullptr;
371 }
372 }
373
374 void ObjArrayKlass::remove_java_mirror() {
375 ArrayKlass::remove_java_mirror();
376 if (_next_refined_array_klass != nullptr && !CDSConfig::is_dumping_dynamic_archive()) {
377 _next_refined_array_klass->remove_java_mirror();
378 }
379 }
380 #endif // INCLUDE_CDS
381
382 u2 ObjArrayKlass::compute_modifier_flags() const {
383 // The modifier for an objectArray is the same as its element
384 assert (element_klass() != nullptr, "should be initialized");
385
386 // Return the flags of the bottom element type.
387 u2 element_flags = bottom_klass()->compute_modifier_flags();
388
389 int identity_flag = (Arguments::is_valhalla_enabled()) ? JVM_ACC_IDENTITY : 0;
390
391 return (element_flags & (JVM_ACC_PUBLIC | JVM_ACC_PRIVATE | JVM_ACC_PROTECTED))
392 | (identity_flag | JVM_ACC_ABSTRACT | JVM_ACC_FINAL);
393 }
394
395 ModuleEntry* ObjArrayKlass::module() const {
396 assert(bottom_klass() != nullptr, "ObjArrayKlass returned unexpected null bottom_klass");
397 // The array is defined in the module of its bottom class
398 return bottom_klass()->module();
399 }
400
401 PackageEntry* ObjArrayKlass::package() const {
402 assert(bottom_klass() != nullptr, "ObjArrayKlass returned unexpected null bottom_klass");
403 return bottom_klass()->package();
404 }
405
406 ObjArrayKlass* ObjArrayKlass::klass_with_properties(ArrayKlass::ArrayProperties props, TRAPS) {
407 assert(props != ArrayProperties::INVALID, "Sanity check");
408 ArrayDescription ad = array_layout_selection(element_klass(), props);
409 props = ad._properties;
410
411 if (properties() == props) {
412 assert(is_refArray_klass() || is_flatArray_klass(), "Must be a concrete array klass");
413 return this;
414 }
415
416 ObjArrayKlass* ak = next_refined_array_klass_acquire();
417 if (ak == nullptr) {
418 // Ensure atomic creation of refined array klasses
419 RecursiveLocker rl(MultiArray_lock, THREAD);
420
421 if (next_refined_array_klass() == nullptr) {
422 ObjArrayKlass* first = this;
423 if (!is_refArray_klass() && !is_flatArray_klass() && props != ArrayKlass::ArrayProperties::DEFAULT) {
424 // Make sure that the first entry in the linked list is always the default refined klass because
425 // C2 relies on this for a fast lookup (see LibraryCallKit::load_default_refined_array_klass).
426 first = allocate_klass_with_properties(ArrayKlass::ArrayProperties::DEFAULT, THREAD);
427 release_set_next_refined_klass(first);
428 }
429 ak = allocate_klass_with_properties(props, THREAD);
430 first->release_set_next_refined_klass(ak);
431 }
432 }
433
434 ak = next_refined_array_klass();
435 assert(ak != nullptr, "should be set");
436 THREAD->check_possible_safepoint();
437 return ak->klass_with_properties(props, THREAD); // why not CHECK_NULL ?
438 }
439
440
441 // Printing
442
443 void ObjArrayKlass::print_on(outputStream* st) const {
444 #ifndef PRODUCT
445 Klass::print_on(st);
446 st->print(" - element klass: ");
447 element_klass()->print_value_on(st);
448 st->cr();
449 #endif //PRODUCT
450 }
451
452 void ObjArrayKlass::print_value_on(outputStream* st) const {
453 assert(is_klass(), "must be klass");
454
455 element_klass()->print_value_on(st);
456 st->print("[]");
457 }
458
459 #ifndef PRODUCT
460
461 void ObjArrayKlass::oop_print_on(oop obj, outputStream* st) {
462 ShouldNotReachHere();
463 }
464
465 #endif //PRODUCT
466
467 void ObjArrayKlass::oop_print_value_on(oop obj, outputStream* st) {
468 ShouldNotReachHere();
469 }
470
471 const char* ObjArrayKlass::internal_name() const {
472 return external_name();
473 }
474
475
476 // Verification
477
478 void ObjArrayKlass::verify_on(outputStream* st) {
479 ArrayKlass::verify_on(st);
480 guarantee(element_klass()->is_klass(), "should be klass");
481 guarantee(bottom_klass()->is_klass(), "should be klass");
482 Klass* bk = bottom_klass();
483 guarantee(bk->is_instance_klass() || bk->is_typeArray_klass() || bk->is_flatArray_klass(),
484 "invalid bottom klass");
485 }
486
487 void ObjArrayKlass::oop_verify_on(oop obj, outputStream* st) {
488 ArrayKlass::oop_verify_on(obj, st);
489 guarantee(obj->is_objArray(), "must be objArray");
490 guarantee(obj->is_null_free_array() || (!is_null_free_array_klass()), "null-free klass but not object");
491 objArrayOop oa = objArrayOop(obj);
492 for(int index = 0; index < oa->length(); index++) {
493 guarantee(oopDesc::is_oop_or_null(oa->obj_at(index)), "should be oop");
494 }
495 }