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(name, Kind) {

124   set_dimension(n);
125   set_element_klass(element_klass);


126 
127   Klass* bk;
128   if (element_klass->is_objArray_klass()) {

129     bk = ObjArrayKlass::cast(element_klass)->bottom_klass();
130   } else {

131     bk = element_klass;
132   }
133   assert(bk != nullptr && (bk->is_instance_klass() || bk->is_typeArray_klass()), "invalid bottom klass");
134   set_bottom_klass(bk);
135   set_class_loader_data(bk->class_loader_data());
136 
137   if (element_klass->is_array_klass()) {
138     set_lower_dimension(ArrayKlass::cast(element_klass));
139   }
140 
141   set_layout_helper(array_layout_helper(T_OBJECT));








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 }
153 
154 objArrayOop ObjArrayKlass::allocate_instance(int length, TRAPS) {
155   check_array_allocation_length(length, arrayOopDesc::max_array_length(T_OBJECT), CHECK_NULL);
156   size_t size = objArrayOopDesc::object_size(length);
157   return (objArrayOop)Universe::heap()->array_allocate(this, size, length,
158                                                        /* do_zero */ true, THREAD);















159 }
160 
161 oop ObjArrayKlass::multi_allocate(int rank, jint* sizes, TRAPS) {
162   int length = *sizes;
163   ArrayKlass* ld_klass = lower_dimension();
164   // If length < 0 allocate will throw an exception.
165   objArrayOop array = allocate_instance(length, CHECK_NULL);


166   objArrayHandle h_array (THREAD, array);
167   if (rank > 1) {
168     if (length != 0) {
169       for (int index = 0; index < length; index++) {
170         oop sub_array = ld_klass->multi_allocate(rank - 1, &sizes[1], CHECK_NULL);
171         h_array->obj_at_put(index, sub_array);
172       }
173     } else {
174       // Since this array dimension has zero length, nothing will be
175       // allocated, however the lower dimension values must be checked
176       // for illegal values.
177       for (int i = 0; i < rank - 1; ++i) {
178         sizes += 1;
179         if (*sizes < 0) {
180           THROW_MSG_NULL(vmSymbols::java_lang_NegativeArraySizeException(), err_msg("%d", *sizes));
181         }
182       }
183     }
184   }
185   return h_array();
186 }
187 
188 static void throw_array_store_exception(arrayOop src, arrayOop dst, TRAPS) {
189   ResourceMark rm(THREAD);
190   Klass* bound = ObjArrayKlass::cast(dst->klass())->element_klass();
191   Klass* stype = ObjArrayKlass::cast(src->klass())->element_klass();
192   stringStream ss;
193   if (!bound->is_subtype_of(stype)) {
194     ss.print("arraycopy: type mismatch: can not copy %s[] into %s[]",
195              stype->external_name(), bound->external_name());
196   } else {
197     // oop_arraycopy should return the index in the source array that
198     // contains the problematic oop.
199     ss.print("arraycopy: element type mismatch: can not cast one of the elements"
200              " of %s[] to the type of the destination array, %s",
201              stype->external_name(), bound->external_name());
202   }
203   THROW_MSG(vmSymbols::java_lang_ArrayStoreException(), ss.as_string());
204 }
205 
206 // Either oop or narrowOop depending on UseCompressedOops.
207 void ObjArrayKlass::do_copy(arrayOop s, size_t src_offset,
208                             arrayOop d, size_t dst_offset, int length, TRAPS) {
209   if (s == d) {
210     // since source and destination are equal we do not need conversion checks.
211     assert(length > 0, "sanity check");
212     OopCopyResult result = ArrayAccess<>::oop_arraycopy(s, src_offset, d, dst_offset, length);
213     assert(result == OopCopyResult::ok, "Should never fail");
214   } else {
215     // We have to make sure all elements conform to the destination array
216     Klass* bound = ObjArrayKlass::cast(d->klass())->element_klass();
217     Klass* stype = ObjArrayKlass::cast(s->klass())->element_klass();
218     bool type_check = stype != bound && !stype->is_subtype_of(bound);
219 
220     auto arraycopy = [&] {
221       if (type_check) {
222         return ArrayAccess<ARRAYCOPY_DISJOINT | ARRAYCOPY_CHECKCAST>::
223             oop_arraycopy(s, src_offset, d, dst_offset, length);
224       } else {
225         return ArrayAccess<ARRAYCOPY_DISJOINT>::
226             oop_arraycopy(s, src_offset, d, dst_offset, length);
227       }
228     };
229 
230     OopCopyResult result = arraycopy();
231 
232     switch (result) {
233     case OopCopyResult::ok:
234       // Done
235       break;
236     case OopCopyResult::failed_check_class_cast:
237       throw_array_store_exception(s, d, JavaThread::current());
238       break;
239     default:
240       ShouldNotReachHere();
241     }
242   }
243 }
244 
245 void ObjArrayKlass::copy_array(arrayOop s, int src_pos, arrayOop d,
246                                int dst_pos, int length, TRAPS) {
247   assert(s->is_objArray(), "must be obj array");
248 
249   if (!d->is_objArray()) {
250     ResourceMark rm(THREAD);
251     stringStream ss;
252     if (d->is_typeArray()) {
253       ss.print("arraycopy: type mismatch: can not copy object array[] into %s[]",
254                type2name_tab[ArrayKlass::cast(d->klass())->element_type()]);
255     } else {
256       ss.print("arraycopy: destination type %s is not an array", d->klass()->external_name());
257     }
258     THROW_MSG(vmSymbols::java_lang_ArrayStoreException(), ss.as_string());
259   }
260 
261   // Check is all offsets and lengths are non negative
262   if (src_pos < 0 || dst_pos < 0 || length < 0) {
263     // Pass specific exception reason.
264     ResourceMark rm(THREAD);
265     stringStream ss;
266     if (src_pos < 0) {
267       ss.print("arraycopy: source index %d out of bounds for object array[%d]",
268                src_pos, s->length());
269     } else if (dst_pos < 0) {
270       ss.print("arraycopy: destination index %d out of bounds for object array[%d]",
271                dst_pos, d->length());
272     } else {
273       ss.print("arraycopy: length %d is negative", length);
274     }
275     THROW_MSG(vmSymbols::java_lang_ArrayIndexOutOfBoundsException(), ss.as_string());
276   }
277   // Check if the ranges are valid
278   if ((((unsigned int) length + (unsigned int) src_pos) > (unsigned int) s->length()) ||
279       (((unsigned int) length + (unsigned int) dst_pos) > (unsigned int) d->length())) {
280     // Pass specific exception reason.
281     ResourceMark rm(THREAD);
282     stringStream ss;
283     if (((unsigned int) length + (unsigned int) src_pos) > (unsigned int) s->length()) {
284       ss.print("arraycopy: last source index %u out of bounds for object array[%d]",
285                (unsigned int) length + (unsigned int) src_pos, s->length());
286     } else {
287       ss.print("arraycopy: last destination index %u out of bounds for object array[%d]",
288                (unsigned int) length + (unsigned int) dst_pos, d->length());
289     }
290     THROW_MSG(vmSymbols::java_lang_ArrayIndexOutOfBoundsException(), ss.as_string());
291   }
292 
293   // Special case. Boundary cases must be checked first
294   // This allows the following call: copy_array(s, s.length(), d.length(), 0).
295   // This is correct, since the position is supposed to be an 'in between point', i.e., s.length(),
296   // points to the right of the last element.
297   if (length==0) {
298     return;
299   }
300   if (UseCompressedOops) {
301     size_t src_offset = (size_t) objArrayOopDesc::obj_at_offset<narrowOop>(src_pos);
302     size_t dst_offset = (size_t) objArrayOopDesc::obj_at_offset<narrowOop>(dst_pos);
303     assert(arrayOopDesc::obj_offset_to_raw<narrowOop>(s, src_offset, nullptr) ==
304            objArrayOop(s)->obj_at_addr<narrowOop>(src_pos), "sanity");
305     assert(arrayOopDesc::obj_offset_to_raw<narrowOop>(d, dst_offset, nullptr) ==
306            objArrayOop(d)->obj_at_addr<narrowOop>(dst_pos), "sanity");
307     do_copy(s, src_offset, d, dst_offset, length, CHECK);
308   } else {
309     size_t src_offset = (size_t) objArrayOopDesc::obj_at_offset<oop>(src_pos);
310     size_t dst_offset = (size_t) objArrayOopDesc::obj_at_offset<oop>(dst_pos);
311     assert(arrayOopDesc::obj_offset_to_raw<oop>(s, src_offset, nullptr) ==
312            objArrayOop(s)->obj_at_addr<oop>(src_pos), "sanity");
313     assert(arrayOopDesc::obj_offset_to_raw<oop>(d, dst_offset, nullptr) ==
314            objArrayOop(d)->obj_at_addr<oop>(dst_pos), "sanity");
315     do_copy(s, src_offset, d, dst_offset, length, CHECK);
316   }
317 }
318 
319 bool ObjArrayKlass::can_be_primary_super_slow() const {
320   if (!bottom_klass()->can_be_primary_super())
321     // array of interfaces
322     return false;
323   else
324     return Klass::can_be_primary_super_slow();
325 }
326 
327 GrowableArray<Klass*>* ObjArrayKlass::compute_secondary_supers(int num_extra_slots,
328                                                                Array<InstanceKlass*>* transitive_interfaces) {
329   assert(transitive_interfaces == nullptr, "sanity");
330   // interfaces = { cloneable_klass, serializable_klass, elemSuper[], ... };
331   const Array<Klass*>* elem_supers = element_klass()->secondary_supers();
332   int num_elem_supers = elem_supers == nullptr ? 0 : elem_supers->length();
333   int num_secondaries = num_extra_slots + 2 + num_elem_supers;
334   if (num_secondaries == 2) {
335     // Must share this for correct bootstrapping!
336     set_secondary_supers(Universe::the_array_interfaces_array(),
337                          Universe::the_array_interfaces_bitmap());
338     return nullptr;
339   } else {
340     GrowableArray<Klass*>* secondaries = new GrowableArray<Klass*>(num_elem_supers+2);
341     secondaries->push(vmClasses::Cloneable_klass());
342     secondaries->push(vmClasses::Serializable_klass());
343     for (int i = 0; i < num_elem_supers; i++) {
344       Klass* elem_super = elem_supers->at(i);
345       Klass* array_super = elem_super->array_klass_or_null();
346       assert(array_super != nullptr, "must already have been created");
347       secondaries->push(array_super);
348     }
349     return secondaries;
350   }
351 }
352 
353 void ObjArrayKlass::initialize(TRAPS) {
354   bottom_klass()->initialize(THREAD);  // dispatches to either InstanceKlass or TypeArrayKlass
355 }
356 
357 void ObjArrayKlass::metaspace_pointers_do(MetaspaceClosure* it) {
358   ArrayKlass::metaspace_pointers_do(it);
359   it->push(&_element_klass);
360   it->push(&_bottom_klass);











361 }
362 

















363 u2 ObjArrayKlass::compute_modifier_flags() const {
364   // The modifier for an objectArray is the same as its element
365   assert (element_klass() != nullptr, "should be initialized");
366 
367   // Return the flags of the bottom element type.
368   u2 element_flags = bottom_klass()->compute_modifier_flags();
369 


370   return (element_flags & (JVM_ACC_PUBLIC | JVM_ACC_PRIVATE | JVM_ACC_PROTECTED))
371                         | (JVM_ACC_ABSTRACT | JVM_ACC_FINAL);
372 }
373 
374 ModuleEntry* ObjArrayKlass::module() const {
375   assert(bottom_klass() != nullptr, "ObjArrayKlass returned unexpected null bottom_klass");
376   // The array is defined in the module of its bottom class
377   return bottom_klass()->module();
378 }
379 
380 PackageEntry* ObjArrayKlass::package() const {
381   assert(bottom_klass() != nullptr, "ObjArrayKlass returned unexpected null bottom_klass");
382   return bottom_klass()->package();
383 }
384 



































385 // Printing
386 
387 void ObjArrayKlass::print_on(outputStream* st) const {
388 #ifndef PRODUCT
389   Klass::print_on(st);
390   st->print(" - instance klass: ");
391   element_klass()->print_value_on(st);
392   st->cr();
393 #endif //PRODUCT
394 }
395 
396 void ObjArrayKlass::print_value_on(outputStream* st) const {
397   assert(is_klass(), "must be klass");
398 
399   element_klass()->print_value_on(st);
400   st->print("[]");
401 }
402 
403 #ifndef PRODUCT
404 
405 void ObjArrayKlass::oop_print_on(oop obj, outputStream* st) {
406   ArrayKlass::oop_print_on(obj, st);
407   assert(obj->is_objArray(), "must be objArray");
408   objArrayOop oa = objArrayOop(obj);
409   int print_len = MIN2(oa->length(), MaxElementPrintSize);
410   for(int index = 0; index < print_len; index++) {
411     st->print(" - %3d : ", index);
412     if (oa->obj_at(index) != nullptr) {
413       oa->obj_at(index)->print_value_on(st);
414       st->cr();
415     } else {
416       st->print_cr("null");
417     }
418   }
419   int remaining = oa->length() - print_len;
420   if (remaining > 0) {
421     st->print_cr(" - <%d more elements, increase MaxElementPrintSize to print>", remaining);
422   }
423 }
424 
425 #endif //PRODUCT
426 
427 void ObjArrayKlass::oop_print_value_on(oop obj, outputStream* st) {
428   assert(obj->is_objArray(), "must be objArray");
429   st->print("a ");
430   element_klass()->print_value_on(st);
431   int len = objArrayOop(obj)->length();
432   st->print("[%d] ", len);
433   if (obj != nullptr) {
434     obj->print_address_on(st);
435   } else {
436     st->print_cr("null");
437   }
438 }
439 
440 const char* ObjArrayKlass::internal_name() const {
441   return external_name();
442 }
443 
444 
445 // Verification
446 
447 void ObjArrayKlass::verify_on(outputStream* st) {
448   ArrayKlass::verify_on(st);
449   guarantee(element_klass()->is_klass(), "should be klass");
450   guarantee(bottom_klass()->is_klass(), "should be klass");
451   Klass* bk = bottom_klass();
452   guarantee(bk->is_instance_klass() || bk->is_typeArray_klass(),  "invalid bottom klass");

453 }
454 
455 void ObjArrayKlass::oop_verify_on(oop obj, outputStream* st) {
456   ArrayKlass::oop_verify_on(obj, st);
457   guarantee(obj->is_objArray(), "must be objArray");

458   objArrayOop oa = objArrayOop(obj);
459   for(int index = 0; index < oa->length(); index++) {
460     guarantee(oopDesc::is_oop_or_null(oa->obj_at(index)), "should be oop");
461   }
462 }
--- EOF ---