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/resourceArea.hpp"
35 #include "memory/universe.hpp"
36 #include "oops/arrayKlass.hpp"
37 #include "oops/instanceKlass.hpp"
38 #include "oops/klass.inline.hpp"
39 #include "oops/objArrayKlass.inline.hpp"
40 #include "oops/objArrayOop.inline.hpp"
41 #include "oops/oop.inline.hpp"
42 #include "oops/symbol.hpp"
43 #include "runtime/handles.inline.hpp"
44 #include "runtime/mutexLocker.hpp"
45 #include "utilities/macros.hpp"
46
47 ObjArrayKlass* ObjArrayKlass::allocate_klass(ClassLoaderData* loader_data, int n, Klass* k, Symbol* name, TRAPS) {
48 assert(ObjArrayKlass::header_size() <= InstanceKlass::header_size(),
49 "array klasses must be same size as InstanceKlass");
50
51 int size = ArrayKlass::static_size(ObjArrayKlass::header_size());
52
53 return new (loader_data, size, THREAD) ObjArrayKlass(n, k, name);
54 }
55
56 Symbol* ObjArrayKlass::create_element_klass_array_name(JavaThread* current, Klass* element_klass) {
57 ResourceMark rm(current);
58 char* name_str = element_klass->name()->as_C_string();
59 int len = element_klass->name()->utf8_length();
60 char* new_str = NEW_RESOURCE_ARRAY_IN_THREAD(current, char, len + 4);
61 int idx = 0;
62 new_str[idx++] = JVM_SIGNATURE_ARRAY;
63 if (element_klass->is_instance_klass()) { // it could be an array or simple type
64 new_str[idx++] = JVM_SIGNATURE_CLASS;
65 }
66 memcpy(&new_str[idx], name_str, len * sizeof(char));
67 idx += len;
68 if (element_klass->is_instance_klass()) {
69 new_str[idx++] = JVM_SIGNATURE_ENDCLASS;
70 }
71 new_str[idx] = '\0';
72 return SymbolTable::new_symbol(new_str);
73 }
74
75
76 ObjArrayKlass* ObjArrayKlass::allocate_objArray_klass(ClassLoaderData* loader_data,
77 int n, Klass* element_klass, TRAPS) {
78
79 // Eagerly allocate the direct array supertype.
80 Klass* super_klass = nullptr;
81 if (!Universe::is_bootstrapping() || vmClasses::Object_klass_is_loaded()) {
82 assert(MultiArray_lock->holds_lock(THREAD), "must hold lock after bootstrapping");
83 Klass* element_super = element_klass->super();
84 if (element_super != nullptr) {
85 // The element type has a direct super. E.g., String[] has direct super of Object[].
86 // Also, see if the element has secondary supertypes.
87 // We need an array type for each before creating this array type.
88 super_klass = element_super->array_klass(CHECK_NULL);
89 const Array<Klass*>* element_supers = element_klass->secondary_supers();
90 for (int i = element_supers->length() - 1; i >= 0; i--) {
91 Klass* elem_super = element_supers->at(i);
92 elem_super->array_klass(CHECK_NULL);
93 }
94 // Fall through because inheritance is acyclic and we hold the global recursive lock to allocate all the arrays.
95 } else {
96 // The element type is already Object. Object[] has direct super of Object.
97 super_klass = vmClasses::Object_klass();
98 }
99 }
100
101 // Create type name for klass.
102 Symbol* name = create_element_klass_array_name(THREAD, element_klass);
103
104 // Initialize instance variables
105 ObjArrayKlass* oak = ObjArrayKlass::allocate_klass(loader_data, n, element_klass, name, CHECK_NULL);
106
107 ModuleEntry* module = oak->module();
108 assert(module != nullptr, "No module entry for array");
109
110 // Call complete_create_array_klass after all instance variables has been initialized.
111 ArrayKlass::complete_create_array_klass(oak, super_klass, module, CHECK_NULL);
112
113 // Add all classes to our internal class loader list here,
114 // including classes in the bootstrap (null) class loader.
115 // Do this step after creating the mirror so that if the
116 // mirror creation fails, loaded_classes_do() doesn't find
117 // an array class without a mirror.
118 loader_data->add_class(oak);
119
120 return oak;
121 }
122
123 ObjArrayKlass::ObjArrayKlass(int n, Klass* element_klass, Symbol* name) : ArrayKlass(n, name, Kind) {
124 set_element_klass(element_klass);
125
126 Klass* bk;
127 if (element_klass->is_objArray_klass()) {
128 bk = ObjArrayKlass::cast(element_klass)->bottom_klass();
129 } else {
130 bk = element_klass;
131 }
132 assert(bk != nullptr && (bk->is_instance_klass() || bk->is_typeArray_klass()), "invalid bottom klass");
133 set_bottom_klass(bk);
134 set_class_loader_data(bk->class_loader_data());
135
136 if (element_klass->is_array_klass()) {
137 set_lower_dimension(ArrayKlass::cast(element_klass));
138 }
139
140 set_layout_helper(array_layout_helper(T_OBJECT));
141 assert(is_array_klass(), "sanity");
142 assert(is_objArray_klass(), "sanity");
143 }
144
145 size_t ObjArrayKlass::oop_size(oop obj) const {
146 // In this assert, we cannot safely access the Klass* with compact headers,
147 // because size_given_klass() calls oop_size() on objects that might be
148 // concurrently forwarded, which would overwrite the Klass*.
149 assert(UseCompactObjectHeaders || obj->is_objArray(), "must be object array");
150 return objArrayOop(obj)->object_size();
151 }
152
153 objArrayOop ObjArrayKlass::allocate_instance(int length, TRAPS) {
154 check_array_allocation_length(length, arrayOopDesc::max_array_length(T_OBJECT), CHECK_NULL);
155 size_t size = objArrayOopDesc::object_size(length);
156 return (objArrayOop)Universe::heap()->array_allocate(this, size, length,
157 /* do_zero */ true, THREAD);
158 }
159
160 oop ObjArrayKlass::multi_allocate(int rank, jint* sizes, TRAPS) {
161 int length = *sizes;
162 ArrayKlass* ld_klass = lower_dimension();
163 // If length < 0 allocate will throw an exception.
164 objArrayOop array = allocate_instance(length, CHECK_NULL);
165 objArrayHandle h_array (THREAD, array);
166 if (rank > 1) {
167 if (length != 0) {
168 for (int index = 0; index < length; index++) {
169 oop sub_array = ld_klass->multi_allocate(rank - 1, &sizes[1], CHECK_NULL);
170 h_array->obj_at_put(index, sub_array);
171 }
172 } else {
173 // Since this array dimension has zero length, nothing will be
174 // allocated, however the lower dimension values must be checked
175 // for illegal values.
176 for (int i = 0; i < rank - 1; ++i) {
177 sizes += 1;
178 if (*sizes < 0) {
179 THROW_MSG_NULL(vmSymbols::java_lang_NegativeArraySizeException(), err_msg("%d", *sizes));
180 }
181 }
182 }
183 }
184 return h_array();
185 }
186
187 static void throw_array_store_exception(arrayOop src, arrayOop dst, TRAPS) {
188 ResourceMark rm(THREAD);
189 Klass* bound = ObjArrayKlass::cast(dst->klass())->element_klass();
190 Klass* stype = ObjArrayKlass::cast(src->klass())->element_klass();
191 stringStream ss;
192 if (!bound->is_subtype_of(stype)) {
193 ss.print("arraycopy: type mismatch: can not copy %s[] into %s[]",
194 stype->external_name(), bound->external_name());
195 } else {
196 // oop_arraycopy should return the index in the source array that
197 // contains the problematic oop.
198 ss.print("arraycopy: element type mismatch: can not cast one of the elements"
199 " of %s[] to the type of the destination array, %s",
200 stype->external_name(), bound->external_name());
201 }
202 THROW_MSG(vmSymbols::java_lang_ArrayStoreException(), ss.as_string());
203 }
204
205 // Either oop or narrowOop depending on UseCompressedOops.
206 void ObjArrayKlass::do_copy(arrayOop s, size_t src_offset,
207 arrayOop d, size_t dst_offset, int length, TRAPS) {
208 if (s == d) {
209 // since source and destination are equal we do not need conversion checks.
210 assert(length > 0, "sanity check");
211 OopCopyResult result = ArrayAccess<>::oop_arraycopy(s, src_offset, d, dst_offset, length);
212 assert(result == OopCopyResult::ok, "Should never fail");
213 } else {
214 // We have to make sure all elements conform to the destination array
215 Klass* bound = ObjArrayKlass::cast(d->klass())->element_klass();
216 Klass* stype = ObjArrayKlass::cast(s->klass())->element_klass();
217 bool type_check = stype != bound && !stype->is_subtype_of(bound);
218
219 auto arraycopy = [&] {
220 if (type_check) {
221 return ArrayAccess<ARRAYCOPY_DISJOINT | ARRAYCOPY_CHECKCAST>::
222 oop_arraycopy(s, src_offset, d, dst_offset, length);
223 } else {
224 return ArrayAccess<ARRAYCOPY_DISJOINT>::
225 oop_arraycopy(s, src_offset, d, dst_offset, length);
226 }
227 };
228
229 OopCopyResult result = arraycopy();
230
231 switch (result) {
232 case OopCopyResult::ok:
233 // Done
234 break;
235 case OopCopyResult::failed_check_class_cast:
236 throw_array_store_exception(s, d, JavaThread::current());
237 break;
238 default:
239 ShouldNotReachHere();
240 }
241 }
242 }
243
244 void ObjArrayKlass::copy_array(arrayOop s, int src_pos, arrayOop d,
245 int dst_pos, int length, TRAPS) {
246 assert(s->is_objArray(), "must be obj array");
247
248 if (!d->is_objArray()) {
249 ResourceMark rm(THREAD);
250 stringStream ss;
251 if (d->is_typeArray()) {
252 ss.print("arraycopy: type mismatch: can not copy object array[] into %s[]",
253 type2name_tab[ArrayKlass::cast(d->klass())->element_type()]);
254 } else {
255 ss.print("arraycopy: destination type %s is not an array", d->klass()->external_name());
256 }
257 THROW_MSG(vmSymbols::java_lang_ArrayStoreException(), ss.as_string());
258 }
259
260 // Check is all offsets and lengths are non negative
261 if (src_pos < 0 || dst_pos < 0 || length < 0) {
262 // Pass specific exception reason.
263 ResourceMark rm(THREAD);
264 stringStream ss;
265 if (src_pos < 0) {
266 ss.print("arraycopy: source index %d out of bounds for object array[%d]",
267 src_pos, s->length());
268 } else if (dst_pos < 0) {
269 ss.print("arraycopy: destination index %d out of bounds for object array[%d]",
270 dst_pos, d->length());
271 } else {
272 ss.print("arraycopy: length %d is negative", length);
273 }
274 THROW_MSG(vmSymbols::java_lang_ArrayIndexOutOfBoundsException(), ss.as_string());
275 }
276 // Check if the ranges are valid
277 if ((((unsigned int) length + (unsigned int) src_pos) > (unsigned int) s->length()) ||
278 (((unsigned int) length + (unsigned int) dst_pos) > (unsigned int) d->length())) {
279 // Pass specific exception reason.
280 ResourceMark rm(THREAD);
281 stringStream ss;
282 if (((unsigned int) length + (unsigned int) src_pos) > (unsigned int) s->length()) {
283 ss.print("arraycopy: last source index %u out of bounds for object array[%d]",
284 (unsigned int) length + (unsigned int) src_pos, s->length());
285 } else {
286 ss.print("arraycopy: last destination index %u out of bounds for object array[%d]",
287 (unsigned int) length + (unsigned int) dst_pos, d->length());
288 }
289 THROW_MSG(vmSymbols::java_lang_ArrayIndexOutOfBoundsException(), ss.as_string());
290 }
291
292 // Special case. Boundary cases must be checked first
293 // This allows the following call: copy_array(s, s.length(), d.length(), 0).
294 // This is correct, since the position is supposed to be an 'in between point', i.e., s.length(),
295 // points to the right of the last element.
296 if (length==0) {
297 return;
298 }
299 if (UseCompressedOops) {
300 size_t src_offset = (size_t) objArrayOopDesc::obj_at_offset<narrowOop>(src_pos);
301 size_t dst_offset = (size_t) objArrayOopDesc::obj_at_offset<narrowOop>(dst_pos);
302 assert(arrayOopDesc::obj_offset_to_raw<narrowOop>(s, src_offset, nullptr) ==
303 objArrayOop(s)->obj_at_addr<narrowOop>(src_pos), "sanity");
304 assert(arrayOopDesc::obj_offset_to_raw<narrowOop>(d, dst_offset, nullptr) ==
305 objArrayOop(d)->obj_at_addr<narrowOop>(dst_pos), "sanity");
306 do_copy(s, src_offset, d, dst_offset, length, CHECK);
307 } else {
308 size_t src_offset = (size_t) objArrayOopDesc::obj_at_offset<oop>(src_pos);
309 size_t dst_offset = (size_t) objArrayOopDesc::obj_at_offset<oop>(dst_pos);
310 assert(arrayOopDesc::obj_offset_to_raw<oop>(s, src_offset, nullptr) ==
311 objArrayOop(s)->obj_at_addr<oop>(src_pos), "sanity");
312 assert(arrayOopDesc::obj_offset_to_raw<oop>(d, dst_offset, nullptr) ==
313 objArrayOop(d)->obj_at_addr<oop>(dst_pos), "sanity");
314 do_copy(s, src_offset, d, dst_offset, length, CHECK);
315 }
316 }
317
318 bool ObjArrayKlass::can_be_primary_super_slow() const {
319 if (!bottom_klass()->can_be_primary_super())
320 // array of interfaces
321 return false;
322 else
323 return Klass::can_be_primary_super_slow();
324 }
325
326 GrowableArray<Klass*>* ObjArrayKlass::compute_secondary_supers(int num_extra_slots,
327 Array<InstanceKlass*>* transitive_interfaces) {
328 assert(transitive_interfaces == nullptr, "sanity");
329 // interfaces = { cloneable_klass, serializable_klass, elemSuper[], ... };
330 const Array<Klass*>* elem_supers = element_klass()->secondary_supers();
331 int num_elem_supers = elem_supers == nullptr ? 0 : elem_supers->length();
332 int num_secondaries = num_extra_slots + 2 + num_elem_supers;
333 if (num_secondaries == 2) {
334 // Must share this for correct bootstrapping!
335 set_secondary_supers(Universe::the_array_interfaces_array(),
336 Universe::the_array_interfaces_bitmap());
337 return nullptr;
338 } else {
339 GrowableArray<Klass*>* secondaries = new GrowableArray<Klass*>(num_elem_supers+2);
340 secondaries->push(vmClasses::Cloneable_klass());
341 secondaries->push(vmClasses::Serializable_klass());
342 for (int i = 0; i < num_elem_supers; i++) {
343 Klass* elem_super = elem_supers->at(i);
344 Klass* array_super = elem_super->array_klass_or_null();
345 assert(array_super != nullptr, "must already have been created");
346 secondaries->push(array_super);
347 }
348 return secondaries;
349 }
350 }
351
352 void ObjArrayKlass::initialize(TRAPS) {
353 bottom_klass()->initialize(THREAD); // dispatches to either InstanceKlass or TypeArrayKlass
354 }
355
356 void ObjArrayKlass::metaspace_pointers_do(MetaspaceClosure* it) {
357 ArrayKlass::metaspace_pointers_do(it);
358 it->push(&_element_klass);
359 it->push(&_bottom_klass);
360 }
361
362 u2 ObjArrayKlass::compute_modifier_flags() const {
363 // The modifier for an objectArray is the same as its element
364 assert (element_klass() != nullptr, "should be initialized");
365
366 // Return the flags of the bottom element type.
367 u2 element_flags = bottom_klass()->compute_modifier_flags();
368
369 return (element_flags & (JVM_ACC_PUBLIC | JVM_ACC_PRIVATE | JVM_ACC_PROTECTED))
370 | (JVM_ACC_ABSTRACT | JVM_ACC_FINAL);
371 }
372
373 ModuleEntry* ObjArrayKlass::module() const {
374 assert(bottom_klass() != nullptr, "ObjArrayKlass returned unexpected null bottom_klass");
375 // The array is defined in the module of its bottom class
376 return bottom_klass()->module();
377 }
378
379 PackageEntry* ObjArrayKlass::package() const {
380 assert(bottom_klass() != nullptr, "ObjArrayKlass returned unexpected null bottom_klass");
381 return bottom_klass()->package();
382 }
383
384 // Printing
385
386 void ObjArrayKlass::print_on(outputStream* st) const {
387 #ifndef PRODUCT
388 Klass::print_on(st);
389 st->print(" - instance klass: ");
390 element_klass()->print_value_on(st);
391 st->cr();
392 #endif //PRODUCT
393 }
394
395 void ObjArrayKlass::print_value_on(outputStream* st) const {
396 assert(is_klass(), "must be klass");
397
398 element_klass()->print_value_on(st);
399 st->print("[]");
400 }
401
402 #ifndef PRODUCT
403
404 void ObjArrayKlass::oop_print_on(oop obj, outputStream* st) {
405 ArrayKlass::oop_print_on(obj, st);
406 assert(obj->is_objArray(), "must be objArray");
407 objArrayOop oa = objArrayOop(obj);
408 int print_len = MIN2(oa->length(), MaxElementPrintSize);
409 for(int index = 0; index < print_len; index++) {
410 st->print(" - %3d : ", index);
411 if (oa->obj_at(index) != nullptr) {
412 oa->obj_at(index)->print_value_on(st);
413 st->cr();
414 } else {
415 st->print_cr("null");
416 }
417 }
418 int remaining = oa->length() - print_len;
419 if (remaining > 0) {
420 st->print_cr(" - <%d more elements, increase MaxElementPrintSize to print>", remaining);
421 }
422 }
423
424 #endif //PRODUCT
425
426 void ObjArrayKlass::oop_print_value_on(oop obj, outputStream* st) {
427 assert(obj->is_objArray(), "must be objArray");
428 st->print("a ");
429 element_klass()->print_value_on(st);
430 int len = objArrayOop(obj)->length();
431 st->print("[%d] ", len);
432 if (obj != nullptr) {
433 obj->print_address_on(st);
434 } else {
435 st->print_cr("null");
436 }
437 }
438
439 const char* ObjArrayKlass::internal_name() const {
440 return external_name();
441 }
442
443
444 // Verification
445
446 void ObjArrayKlass::verify_on(outputStream* st) {
447 ArrayKlass::verify_on(st);
448 guarantee(element_klass()->is_klass(), "should be klass");
449 guarantee(bottom_klass()->is_klass(), "should be klass");
450 Klass* bk = bottom_klass();
451 guarantee(bk->is_instance_klass() || bk->is_typeArray_klass(), "invalid bottom klass");
452 }
453
454 void ObjArrayKlass::oop_verify_on(oop obj, outputStream* st) {
455 ArrayKlass::oop_verify_on(obj, st);
456 guarantee(obj->is_objArray(), "must be objArray");
457 objArrayOop oa = objArrayOop(obj);
458 for(int index = 0; index < oa->length(); index++) {
459 guarantee(oopDesc::is_oop_or_null(oa->obj_at(index)), "should be oop");
460 }
461 }