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 "classfile/moduleEntry.hpp"
26 #include "classfile/packageEntry.hpp"
27 #include "classfile/symbolTable.hpp"
28 #include "classfile/vmClasses.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "gc/shared/collectedHeap.inline.hpp"
31 #include "memory/iterator.inline.hpp"
32 #include "memory/metadataFactory.hpp"
33 #include "memory/metaspaceClosure.hpp"
34 #include "memory/oopFactory.hpp"
35 #include "memory/resourceArea.hpp"
36 #include "memory/universe.hpp"
37 #include "oops/arrayKlass.hpp"
38 #include "oops/instanceKlass.hpp"
39 #include "oops/klass.inline.hpp"
40 #include "oops/markWord.hpp"
41 #include "oops/objArrayKlass.inline.hpp"
42 #include "oops/objArrayOop.inline.hpp"
43 #include "oops/oop.inline.hpp"
44 #include "oops/symbol.hpp"
45 #include "runtime/handles.inline.hpp"
46 #include "runtime/mutexLocker.hpp"
47 #include "utilities/macros.hpp"
48
49 ObjArrayKlass* ObjArrayKlass::allocate(ClassLoaderData* loader_data, int n,
50 Klass* k, Symbol* name, bool null_free,
51 TRAPS) {
52 assert(ObjArrayKlass::header_size() <= InstanceKlass::header_size(),
53 "array klasses must be same size as InstanceKlass");
54
55 int size = ArrayKlass::static_size(ObjArrayKlass::header_size());
56
57 return new (loader_data, size, THREAD) ObjArrayKlass(n, k, name, null_free);
58 }
59
60 ObjArrayKlass* ObjArrayKlass::allocate_objArray_klass(ClassLoaderData* loader_data,
61 int n, Klass* element_klass,
62 bool null_free, TRAPS) {
63 assert(!null_free || (n == 1 && element_klass->is_inline_klass()), "null-free unsupported");
64
65 // Eagerly allocate the direct array supertype.
66 Klass* super_klass = nullptr;
67 if (!Universe::is_bootstrapping() || vmClasses::Object_klass_loaded()) {
68 assert(MultiArray_lock->holds_lock(THREAD), "must hold lock after bootstrapping");
69 Klass* element_super = element_klass->super();
70 if (element_super != nullptr) {
71 // The element type has a direct super. E.g., String[] has direct super of Object[].
72 // Also, see if the element has secondary supertypes.
73 // We need an array type for each before creating this array type.
74 if (null_free) {
75 super_klass = element_klass->array_klass(CHECK_NULL);
76 } else {
77 super_klass = element_super->array_klass(CHECK_NULL);
78 }
79 const Array<Klass*>* element_supers = element_klass->secondary_supers();
80 for (int i = element_supers->length() - 1; i >= 0; i--) {
81 Klass* elem_super = element_supers->at(i);
82 elem_super->array_klass(CHECK_NULL);
83 }
84 // Fall through because inheritance is acyclic and we hold the global recursive lock to allocate all the arrays.
85 } else {
86 // The element type is already Object. Object[] has direct super of Object.
87 super_klass = vmClasses::Object_klass();
88 }
89 }
90
91 // Create type name for klass.
92 Symbol* name = ArrayKlass::create_element_klass_array_name(element_klass, CHECK_NULL);
93
94 // Initialize instance variables
95 ObjArrayKlass* oak = ObjArrayKlass::allocate(loader_data, n, element_klass, name, null_free, CHECK_NULL);
96
97 ModuleEntry* module = oak->module();
98 assert(module != nullptr, "No module entry for array");
99
100 // Call complete_create_array_klass after all instance variables has been initialized.
101 ArrayKlass::complete_create_array_klass(oak, super_klass, module, CHECK_NULL);
102
103 // Add all classes to our internal class loader list here,
104 // including classes in the bootstrap (null) class loader.
105 // Do this step after creating the mirror so that if the
106 // mirror creation fails, loaded_classes_do() doesn't find
107 // an array class without a mirror.
108 loader_data->add_class(oak);
109
110 return oak;
111 }
112
113 ObjArrayKlass::ObjArrayKlass(int n, Klass* element_klass, Symbol* name, bool null_free) :
114 ArrayKlass(name, Kind, null_free ? markWord::null_free_array_prototype() : markWord::prototype()) {
115 set_dimension(n);
116 set_element_klass(element_klass);
117
118 Klass* bk;
119 if (element_klass->is_objArray_klass()) {
120 bk = ObjArrayKlass::cast(element_klass)->bottom_klass();
121 } else if (element_klass->is_flatArray_klass()) {
122 bk = FlatArrayKlass::cast(element_klass)->element_klass();
123 } else {
124 bk = element_klass;
125 }
126 assert(bk != nullptr && (bk->is_instance_klass() || bk->is_typeArray_klass()), "invalid bottom klass");
127 set_bottom_klass(bk);
128 set_class_loader_data(bk->class_loader_data());
129
130 if (element_klass->is_array_klass()) {
131 set_lower_dimension(ArrayKlass::cast(element_klass));
132 }
133
134 int lh = array_layout_helper(T_OBJECT);
135 if (null_free) {
136 assert(n == 1, "Bytecode does not support null-free multi-dim");
137 lh = layout_helper_set_null_free(lh);
138 #ifdef _LP64
139 assert(prototype_header().is_null_free_array(), "sanity");
140 #endif
141 }
142 set_layout_helper(lh);
143 assert(is_array_klass(), "sanity");
144 assert(is_objArray_klass(), "sanity");
145 }
146
147 size_t ObjArrayKlass::oop_size(oop obj) const {
148 // In this assert, we cannot safely access the Klass* with compact headers,
149 // because size_given_klass() calls oop_size() on objects that might be
150 // concurrently forwarded, which would overwrite the Klass*.
151 assert(UseCompactObjectHeaders || obj->is_objArray(), "must be object array");
152 return objArrayOop(obj)->object_size();
153 }
154
155 objArrayOop ObjArrayKlass::allocate(int length, TRAPS) {
156 check_array_allocation_length(length, arrayOopDesc::max_array_length(T_OBJECT), CHECK_NULL);
157 size_t size = objArrayOopDesc::object_size(length);
158 objArrayOop array = (objArrayOop)Universe::heap()->array_allocate(this, size, length,
159 /* do_zero */ true, CHECK_NULL);
160 objArrayHandle array_h(THREAD, array);
161 return array_h();
162 }
163
164 oop ObjArrayKlass::multi_allocate(int rank, jint* sizes, TRAPS) {
165 int length = *sizes;
166 ArrayKlass* ld_klass = lower_dimension();
167 // If length < 0 allocate will throw an exception.
168 objArrayOop array = allocate(length, CHECK_NULL);
169 objArrayHandle h_array (THREAD, array);
170 if (rank > 1) {
171 if (length != 0) {
172 for (int index = 0; index < length; index++) {
173 oop sub_array = ld_klass->multi_allocate(rank-1, &sizes[1], CHECK_NULL);
174 h_array->obj_at_put(index, sub_array);
175 }
176 } else {
177 // Since this array dimension has zero length, nothing will be
178 // allocated, however the lower dimension values must be checked
179 // for illegal values.
180 for (int i = 0; i < rank - 1; ++i) {
181 sizes += 1;
182 if (*sizes < 0) {
183 THROW_MSG_NULL(vmSymbols::java_lang_NegativeArraySizeException(), err_msg("%d", *sizes));
184 }
185 }
186 }
187 }
188 return h_array();
189 }
190
191 // Either oop or narrowOop depending on UseCompressedOops.
192 void ObjArrayKlass::do_copy(arrayOop s, size_t src_offset,
193 arrayOop d, size_t dst_offset, int length, TRAPS) {
194 if (s == d) {
195 // since source and destination are equal we do not need conversion checks.
196 assert(length > 0, "sanity check");
197 ArrayAccess<>::oop_arraycopy(s, src_offset, d, dst_offset, length);
198 } else {
199 // We have to make sure all elements conform to the destination array
200 Klass* bound = ObjArrayKlass::cast(d->klass())->element_klass();
201 Klass* stype = ObjArrayKlass::cast(s->klass())->element_klass();
202 // Perform null check if dst is null-free but src has no such guarantee
203 bool null_check = ((!s->klass()->is_null_free_array_klass()) &&
204 d->klass()->is_null_free_array_klass());
205 if (stype == bound || stype->is_subtype_of(bound)) {
206 if (null_check) {
207 ArrayAccess<ARRAYCOPY_DISJOINT | ARRAYCOPY_NOTNULL>::oop_arraycopy(s, src_offset, d, dst_offset, length);
208 } else {
209 ArrayAccess<ARRAYCOPY_DISJOINT>::oop_arraycopy(s, src_offset, d, dst_offset, length);
210 }
211 } else {
212 if (null_check) {
213 ArrayAccess<ARRAYCOPY_DISJOINT | ARRAYCOPY_CHECKCAST | ARRAYCOPY_NOTNULL>::oop_arraycopy(s, src_offset, d, dst_offset, length);
214 } else {
215 ArrayAccess<ARRAYCOPY_DISJOINT | ARRAYCOPY_CHECKCAST>::oop_arraycopy(s, src_offset, d, dst_offset, length);
216 }
217 }
218 }
219 }
220
221 void ObjArrayKlass::copy_array(arrayOop s, int src_pos, arrayOop d,
222 int dst_pos, int length, TRAPS) {
223 assert(s->is_objArray(), "must be obj array");
224
225 if (UseArrayFlattening) {
226 if (d->is_flatArray()) {
227 FlatArrayKlass::cast(d->klass())->copy_array(s, src_pos, d, dst_pos, length, THREAD);
228 return;
229 }
230 }
231
232 if (!d->is_objArray()) {
233 ResourceMark rm(THREAD);
234 stringStream ss;
235 if (d->is_typeArray()) {
236 ss.print("arraycopy: type mismatch: can not copy object array[] into %s[]",
237 type2name_tab[ArrayKlass::cast(d->klass())->element_type()]);
238 } else {
239 ss.print("arraycopy: destination type %s is not an array", d->klass()->external_name());
240 }
241 THROW_MSG(vmSymbols::java_lang_ArrayStoreException(), ss.as_string());
242 }
243
244 // Check is all offsets and lengths are non negative
245 if (src_pos < 0 || dst_pos < 0 || length < 0) {
246 // Pass specific exception reason.
247 ResourceMark rm(THREAD);
248 stringStream ss;
249 if (src_pos < 0) {
250 ss.print("arraycopy: source index %d out of bounds for object array[%d]",
251 src_pos, s->length());
252 } else if (dst_pos < 0) {
253 ss.print("arraycopy: destination index %d out of bounds for object array[%d]",
254 dst_pos, d->length());
255 } else {
256 ss.print("arraycopy: length %d is negative", length);
257 }
258 THROW_MSG(vmSymbols::java_lang_ArrayIndexOutOfBoundsException(), ss.as_string());
259 }
260 // Check if the ranges are valid
261 if ((((unsigned int) length + (unsigned int) src_pos) > (unsigned int) s->length()) ||
262 (((unsigned int) length + (unsigned int) dst_pos) > (unsigned int) d->length())) {
263 // Pass specific exception reason.
264 ResourceMark rm(THREAD);
265 stringStream ss;
266 if (((unsigned int) length + (unsigned int) src_pos) > (unsigned int) s->length()) {
267 ss.print("arraycopy: last source index %u out of bounds for object array[%d]",
268 (unsigned int) length + (unsigned int) src_pos, s->length());
269 } else {
270 ss.print("arraycopy: last destination index %u out of bounds for object array[%d]",
271 (unsigned int) length + (unsigned int) dst_pos, d->length());
272 }
273 THROW_MSG(vmSymbols::java_lang_ArrayIndexOutOfBoundsException(), ss.as_string());
274 }
275
276 // Special case. Boundary cases must be checked first
277 // This allows the following call: copy_array(s, s.length(), d.length(), 0).
278 // This is correct, since the position is supposed to be an 'in between point', i.e., s.length(),
279 // points to the right of the last element.
280 if (length==0) {
281 return;
282 }
283 if (UseCompressedOops) {
284 size_t src_offset = (size_t) objArrayOopDesc::obj_at_offset<narrowOop>(src_pos);
285 size_t dst_offset = (size_t) objArrayOopDesc::obj_at_offset<narrowOop>(dst_pos);
286 assert(arrayOopDesc::obj_offset_to_raw<narrowOop>(s, src_offset, nullptr) ==
287 objArrayOop(s)->obj_at_addr<narrowOop>(src_pos), "sanity");
288 assert(arrayOopDesc::obj_offset_to_raw<narrowOop>(d, dst_offset, nullptr) ==
289 objArrayOop(d)->obj_at_addr<narrowOop>(dst_pos), "sanity");
290 do_copy(s, src_offset, d, dst_offset, length, CHECK);
291 } else {
292 size_t src_offset = (size_t) objArrayOopDesc::obj_at_offset<oop>(src_pos);
293 size_t dst_offset = (size_t) objArrayOopDesc::obj_at_offset<oop>(dst_pos);
294 assert(arrayOopDesc::obj_offset_to_raw<oop>(s, src_offset, nullptr) ==
295 objArrayOop(s)->obj_at_addr<oop>(src_pos), "sanity");
296 assert(arrayOopDesc::obj_offset_to_raw<oop>(d, dst_offset, nullptr) ==
297 objArrayOop(d)->obj_at_addr<oop>(dst_pos), "sanity");
298 do_copy(s, src_offset, d, dst_offset, length, CHECK);
299 }
300 }
301
302 bool ObjArrayKlass::can_be_primary_super_slow() const {
303 if (!bottom_klass()->can_be_primary_super())
304 // array of interfaces
305 return false;
306 else
307 return Klass::can_be_primary_super_slow();
308 }
309
310 GrowableArray<Klass*>* ObjArrayKlass::compute_secondary_supers(int num_extra_slots,
311 Array<InstanceKlass*>* transitive_interfaces) {
312 assert(transitive_interfaces == nullptr, "sanity");
313 // interfaces = { cloneable_klass, serializable_klass, elemSuper[], ... };
314 const Array<Klass*>* elem_supers = element_klass()->secondary_supers();
315 int num_elem_supers = elem_supers == nullptr ? 0 : elem_supers->length();
316 int num_secondaries = num_extra_slots + 2 + num_elem_supers;
317 if (num_secondaries == 2) {
318 // Must share this for correct bootstrapping!
319 set_secondary_supers(Universe::the_array_interfaces_array(),
320 Universe::the_array_interfaces_bitmap());
321 return nullptr;
322 } else {
323 GrowableArray<Klass*>* secondaries = new GrowableArray<Klass*>(num_elem_supers+2);
324 secondaries->push(vmClasses::Cloneable_klass());
325 secondaries->push(vmClasses::Serializable_klass());
326 for (int i = 0; i < num_elem_supers; i++) {
327 Klass* elem_super = elem_supers->at(i);
328 Klass* array_super = elem_super->array_klass_or_null();
329 assert(array_super != nullptr, "must already have been created");
330 secondaries->push(array_super);
331 }
332 return secondaries;
333 }
334 }
335
336 void ObjArrayKlass::initialize(TRAPS) {
337 bottom_klass()->initialize(THREAD); // dispatches to either InstanceKlass or TypeArrayKlass
338 }
339
340 void ObjArrayKlass::metaspace_pointers_do(MetaspaceClosure* it) {
341 ArrayKlass::metaspace_pointers_do(it);
342 it->push(&_element_klass);
343 it->push(&_bottom_klass);
344 }
345
346 u2 ObjArrayKlass::compute_modifier_flags() const {
347 // The modifier for an objectArray is the same as its element
348 assert (element_klass() != nullptr, "should be initialized");
349
350 // Return the flags of the bottom element type.
351 u2 element_flags = bottom_klass()->compute_modifier_flags();
352
353 int identity_flag = (Arguments::enable_preview()) ? JVM_ACC_IDENTITY : 0;
354
355 return (element_flags & (JVM_ACC_PUBLIC | JVM_ACC_PRIVATE | JVM_ACC_PROTECTED))
356 | (identity_flag | JVM_ACC_ABSTRACT | JVM_ACC_FINAL);
357 }
358
359 ModuleEntry* ObjArrayKlass::module() const {
360 assert(bottom_klass() != nullptr, "ObjArrayKlass returned unexpected null bottom_klass");
361 // The array is defined in the module of its bottom class
362 return bottom_klass()->module();
363 }
364
365 PackageEntry* ObjArrayKlass::package() const {
366 assert(bottom_klass() != nullptr, "ObjArrayKlass returned unexpected null bottom_klass");
367 return bottom_klass()->package();
368 }
369
370 // Printing
371
372 void ObjArrayKlass::print_on(outputStream* st) const {
373 #ifndef PRODUCT
374 Klass::print_on(st);
375 st->print(" - element klass: ");
376 element_klass()->print_value_on(st);
377 st->cr();
378 #endif //PRODUCT
379 }
380
381 void ObjArrayKlass::print_value_on(outputStream* st) const {
382 assert(is_klass(), "must be klass");
383
384 element_klass()->print_value_on(st);
385 st->print("[]");
386 }
387
388 #ifndef PRODUCT
389
390 void ObjArrayKlass::oop_print_on(oop obj, outputStream* st) {
391 ArrayKlass::oop_print_on(obj, st);
392 assert(obj->is_objArray(), "must be objArray");
393 objArrayOop oa = objArrayOop(obj);
394 int print_len = MIN2(oa->length(), MaxElementPrintSize);
395 for(int index = 0; index < print_len; index++) {
396 st->print(" - %3d : ", index);
397 if (oa->obj_at(index) != nullptr) {
398 oa->obj_at(index)->print_value_on(st);
399 st->cr();
400 } else {
401 st->print_cr("null");
402 }
403 }
404 int remaining = oa->length() - print_len;
405 if (remaining > 0) {
406 st->print_cr(" - <%d more elements, increase MaxElementPrintSize to print>", remaining);
407 }
408 }
409
410 #endif //PRODUCT
411
412 void ObjArrayKlass::oop_print_value_on(oop obj, outputStream* st) {
413 assert(obj->is_objArray(), "must be objArray");
414 st->print("a ");
415 element_klass()->print_value_on(st);
416 int len = objArrayOop(obj)->length();
417 st->print("[%d] ", len);
418 if (obj != nullptr) {
419 obj->print_address_on(st);
420 } else {
421 st->print_cr("null");
422 }
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 }