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(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 ObjArrayKlass* ObjArrayKlass::allocate_objArray_klass(ClassLoaderData* loader_data,
 57                                                       int n, Klass* element_klass, TRAPS) {
 58 
 59   // Eagerly allocate the direct array supertype.
 60   Klass* super_klass = nullptr;
 61   if (!Universe::is_bootstrapping() || vmClasses::Object_klass_loaded()) {
 62     assert(MultiArray_lock->holds_lock(THREAD), "must hold lock after bootstrapping");
 63     Klass* element_super = element_klass->super();
 64     if (element_super != nullptr) {
 65       // The element type has a direct super.  E.g., String[] has direct super of Object[].
 66       // Also, see if the element has secondary supertypes.
 67       // We need an array type for each before creating this array type.
 68       super_klass = element_super->array_klass(CHECK_NULL);
 69       const Array<Klass*>* element_supers = element_klass->secondary_supers();
 70       for (int i = element_supers->length() - 1; i >= 0; i--) {
 71         Klass* elem_super = element_supers->at(i);
 72         elem_super->array_klass(CHECK_NULL);
 73       }
 74       // Fall through because inheritance is acyclic and we hold the global recursive lock to allocate all the arrays.
 75     } else {
 76       // The element type is already Object.  Object[] has direct super of Object.
 77       super_klass = vmClasses::Object_klass();
 78     }
 79   }
 80 
 81   // Create type name for klass.
 82   Symbol* name = nullptr;
 83   {
 84     ResourceMark rm(THREAD);
 85     char *name_str = element_klass->name()->as_C_string();
 86     int len = element_klass->name()->utf8_length();
 87     char *new_str = NEW_RESOURCE_ARRAY(char, len + 4);
 88     int idx = 0;
 89     new_str[idx++] = JVM_SIGNATURE_ARRAY;
 90     if (element_klass->is_instance_klass()) { // it could be an array or simple type
 91       new_str[idx++] = JVM_SIGNATURE_CLASS;
 92     }
 93     memcpy(&new_str[idx], name_str, len * sizeof(char));
 94     idx += len;
 95     if (element_klass->is_instance_klass()) {
 96       new_str[idx++] = JVM_SIGNATURE_ENDCLASS;
 97     }
 98     new_str[idx++] = '\0';
 99     name = SymbolTable::new_symbol(new_str);
100   }
101 
102   // Initialize instance variables
103   ObjArrayKlass* oak = ObjArrayKlass::allocate(loader_data, n, element_klass, name, CHECK_NULL);
104 
105   ModuleEntry* module = oak->module();
106   assert(module != nullptr, "No module entry for array");
107 
108   // Call complete_create_array_klass after all instance variables has been initialized.
109   ArrayKlass::complete_create_array_klass(oak, super_klass, module, CHECK_NULL);
110 
111   // Add all classes to our internal class loader list here,
112   // including classes in the bootstrap (null) class loader.
113   // Do this step after creating the mirror so that if the
114   // mirror creation fails, loaded_classes_do() doesn't find
115   // an array class without a mirror.
116   loader_data->add_class(oak);
117 
118   return oak;
119 }
120 
121 ObjArrayKlass::ObjArrayKlass(int n, Klass* element_klass, Symbol* name) : ArrayKlass(name, Kind) {
122   set_dimension(n);
123   set_element_klass(element_klass);
124 
125   Klass* bk;
126   if (element_klass->is_objArray_klass()) {
127     bk = ObjArrayKlass::cast(element_klass)->bottom_klass();
128   } else {
129     bk = element_klass;
130   }
131   assert(bk != nullptr && (bk->is_instance_klass() || bk->is_typeArray_klass()), "invalid bottom klass");
132   set_bottom_klass(bk);
133   set_class_loader_data(bk->class_loader_data());
134 
135   if (element_klass->is_array_klass()) {
136     set_lower_dimension(ArrayKlass::cast(element_klass));
137   }
138 
139   set_layout_helper(array_layout_helper(T_OBJECT));
140   assert(is_array_klass(), "sanity");
141   assert(is_objArray_klass(), "sanity");
142 
143   // Compute modifier flags after bottom_klass and element_klass are initialized.
144   set_modifier_flags(compute_modifier_flags());
145 }
146 
147 size_t ObjArrayKlass::oop_size(oop obj, markWord mark) 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   int length = LP64_ONLY(UseCompactObjectHeaders ? mark.array_length() :) objArrayOop(obj)->length();
153   return objArrayOop(obj)->object_size(length);
154 }
155 
156 objArrayOop ObjArrayKlass::allocate(int length, TRAPS) {
157   check_array_allocation_length(length, arrayOopDesc::max_array_length(T_OBJECT), CHECK_NULL);
158   size_t size = objArrayOopDesc::object_size(length);
159   return (objArrayOop)Universe::heap()->array_allocate(this, size, length,
160                                                        /* do_zero */ true, THREAD);
161 }
162 
163 oop ObjArrayKlass::multi_allocate(int rank, jint* sizes, TRAPS) {
164   int length = *sizes;
165   ArrayKlass* ld_klass = lower_dimension();
166   // If length < 0 allocate will throw an exception.
167   objArrayOop array = allocate(length, CHECK_NULL);
168   objArrayHandle h_array (THREAD, array);
169   if (rank > 1) {
170     if (length != 0) {
171       for (int index = 0; index < length; index++) {
172         oop sub_array = ld_klass->multi_allocate(rank - 1, &sizes[1], CHECK_NULL);
173         h_array->obj_at_put(index, sub_array);
174       }
175     } else {
176       // Since this array dimension has zero length, nothing will be
177       // allocated, however the lower dimension values must be checked
178       // for illegal values.
179       for (int i = 0; i < rank - 1; ++i) {
180         sizes += 1;
181         if (*sizes < 0) {
182           THROW_MSG_NULL(vmSymbols::java_lang_NegativeArraySizeException(), err_msg("%d", *sizes));
183         }
184       }
185     }
186   }
187   return h_array();
188 }
189 
190 // Either oop or narrowOop depending on UseCompressedOops.
191 void ObjArrayKlass::do_copy(arrayOop s, size_t src_offset,
192                             arrayOop d, size_t dst_offset, int length, TRAPS) {
193   if (s == d) {
194     // since source and destination are equal we do not need conversion checks.
195     assert(length > 0, "sanity check");
196     ArrayAccess<>::oop_arraycopy(s, src_offset, d, dst_offset, length);
197   } else {
198     // We have to make sure all elements conform to the destination array
199     Klass* bound = ObjArrayKlass::cast(d->klass())->element_klass();
200     Klass* stype = ObjArrayKlass::cast(s->klass())->element_klass();
201     if (stype == bound || stype->is_subtype_of(bound)) {
202       // elements are guaranteed to be subtypes, so no check necessary
203       ArrayAccess<ARRAYCOPY_DISJOINT>::oop_arraycopy(s, src_offset, d, dst_offset, length);
204     } else {
205       // slow case: need individual subtype checks
206       // note: don't use obj_at_put below because it includes a redundant store check
207       if (!ArrayAccess<ARRAYCOPY_DISJOINT | ARRAYCOPY_CHECKCAST>::oop_arraycopy(s, src_offset, d, dst_offset, length)) {
208         ResourceMark rm(THREAD);
209         stringStream ss;
210         if (!bound->is_subtype_of(stype)) {
211           ss.print("arraycopy: type mismatch: can not copy %s[] into %s[]",
212                    stype->external_name(), bound->external_name());
213         } else {
214           // oop_arraycopy should return the index in the source array that
215           // contains the problematic oop.
216           ss.print("arraycopy: element type mismatch: can not cast one of the elements"
217                    " of %s[] to the type of the destination array, %s",
218                    stype->external_name(), bound->external_name());
219         }
220         THROW_MSG(vmSymbols::java_lang_ArrayStoreException(), ss.as_string());
221       }
222     }
223   }
224 }
225 
226 void ObjArrayKlass::copy_array(arrayOop s, int src_pos, arrayOop d,
227                                int dst_pos, int length, TRAPS) {
228   assert(s->is_objArray(), "must be obj array");
229 
230   if (!d->is_objArray()) {
231     ResourceMark rm(THREAD);
232     stringStream ss;
233     if (d->is_typeArray()) {
234       ss.print("arraycopy: type mismatch: can not copy object array[] into %s[]",
235                type2name_tab[ArrayKlass::cast(d->klass())->element_type()]);
236     } else {
237       ss.print("arraycopy: destination type %s is not an array", d->klass()->external_name());
238     }
239     THROW_MSG(vmSymbols::java_lang_ArrayStoreException(), ss.as_string());
240   }
241 
242   // Check is all offsets and lengths are non negative
243   if (src_pos < 0 || dst_pos < 0 || length < 0) {
244     // Pass specific exception reason.
245     ResourceMark rm(THREAD);
246     stringStream ss;
247     if (src_pos < 0) {
248       ss.print("arraycopy: source index %d out of bounds for object array[%d]",
249                src_pos, s->length());
250     } else if (dst_pos < 0) {
251       ss.print("arraycopy: destination index %d out of bounds for object array[%d]",
252                dst_pos, d->length());
253     } else {
254       ss.print("arraycopy: length %d is negative", length);
255     }
256     THROW_MSG(vmSymbols::java_lang_ArrayIndexOutOfBoundsException(), ss.as_string());
257   }
258   // Check if the ranges are valid
259   if ((((unsigned int) length + (unsigned int) src_pos) > (unsigned int) s->length()) ||
260       (((unsigned int) length + (unsigned int) dst_pos) > (unsigned int) d->length())) {
261     // Pass specific exception reason.
262     ResourceMark rm(THREAD);
263     stringStream ss;
264     if (((unsigned int) length + (unsigned int) src_pos) > (unsigned int) s->length()) {
265       ss.print("arraycopy: last source index %u out of bounds for object array[%d]",
266                (unsigned int) length + (unsigned int) src_pos, s->length());
267     } else {
268       ss.print("arraycopy: last destination index %u out of bounds for object array[%d]",
269                (unsigned int) length + (unsigned int) dst_pos, d->length());
270     }
271     THROW_MSG(vmSymbols::java_lang_ArrayIndexOutOfBoundsException(), ss.as_string());
272   }
273 
274   // Special case. Boundary cases must be checked first
275   // This allows the following call: copy_array(s, s.length(), d.length(), 0).
276   // This is correct, since the position is supposed to be an 'in between point', i.e., s.length(),
277   // points to the right of the last element.
278   if (length==0) {
279     return;
280   }
281   if (UseCompressedOops) {
282     size_t src_offset = (size_t) objArrayOopDesc::obj_at_offset<narrowOop>(src_pos);
283     size_t dst_offset = (size_t) objArrayOopDesc::obj_at_offset<narrowOop>(dst_pos);
284     assert(arrayOopDesc::obj_offset_to_raw<narrowOop>(s, src_offset, nullptr) ==
285            objArrayOop(s)->obj_at_addr<narrowOop>(src_pos), "sanity");
286     assert(arrayOopDesc::obj_offset_to_raw<narrowOop>(d, dst_offset, nullptr) ==
287            objArrayOop(d)->obj_at_addr<narrowOop>(dst_pos), "sanity");
288     do_copy(s, src_offset, d, dst_offset, length, CHECK);
289   } else {
290     size_t src_offset = (size_t) objArrayOopDesc::obj_at_offset<oop>(src_pos);
291     size_t dst_offset = (size_t) objArrayOopDesc::obj_at_offset<oop>(dst_pos);
292     assert(arrayOopDesc::obj_offset_to_raw<oop>(s, src_offset, nullptr) ==
293            objArrayOop(s)->obj_at_addr<oop>(src_pos), "sanity");
294     assert(arrayOopDesc::obj_offset_to_raw<oop>(d, dst_offset, nullptr) ==
295            objArrayOop(d)->obj_at_addr<oop>(dst_pos), "sanity");
296     do_copy(s, src_offset, d, dst_offset, length, CHECK);
297   }
298 }
299 
300 bool ObjArrayKlass::can_be_primary_super_slow() const {
301   if (!bottom_klass()->can_be_primary_super())
302     // array of interfaces
303     return false;
304   else
305     return Klass::can_be_primary_super_slow();
306 }
307 
308 GrowableArray<Klass*>* ObjArrayKlass::compute_secondary_supers(int num_extra_slots,
309                                                                Array<InstanceKlass*>* transitive_interfaces) {
310   assert(transitive_interfaces == nullptr, "sanity");
311   // interfaces = { cloneable_klass, serializable_klass, elemSuper[], ... };
312   const Array<Klass*>* elem_supers = element_klass()->secondary_supers();
313   int num_elem_supers = elem_supers == nullptr ? 0 : elem_supers->length();
314   int num_secondaries = num_extra_slots + 2 + num_elem_supers;
315   if (num_secondaries == 2) {
316     // Must share this for correct bootstrapping!
317     set_secondary_supers(Universe::the_array_interfaces_array(),
318                          Universe::the_array_interfaces_bitmap());
319     return nullptr;
320   } else {
321     GrowableArray<Klass*>* secondaries = new GrowableArray<Klass*>(num_elem_supers+2);
322     secondaries->push(vmClasses::Cloneable_klass());
323     secondaries->push(vmClasses::Serializable_klass());
324     for (int i = 0; i < num_elem_supers; i++) {
325       Klass* elem_super = elem_supers->at(i);
326       Klass* array_super = elem_super->array_klass_or_null();
327       assert(array_super != nullptr, "must already have been created");
328       secondaries->push(array_super);
329     }
330     return secondaries;
331   }
332 }
333 
334 void ObjArrayKlass::initialize(TRAPS) {
335   bottom_klass()->initialize(THREAD);  // dispatches to either InstanceKlass or TypeArrayKlass
336 }
337 
338 void ObjArrayKlass::metaspace_pointers_do(MetaspaceClosure* it) {
339   ArrayKlass::metaspace_pointers_do(it);
340   it->push(&_element_klass);
341   it->push(&_bottom_klass);
342 }
343 
344 u2 ObjArrayKlass::compute_modifier_flags() const {
345   // The modifier for an objectArray is the same as its element
346   assert (element_klass() != nullptr, "should be initialized");
347 
348   // Return the flags of the bottom element type.
349   u2 element_flags = bottom_klass()->compute_modifier_flags();
350 
351   return (element_flags & (JVM_ACC_PUBLIC | JVM_ACC_PRIVATE | JVM_ACC_PROTECTED))
352                         | (JVM_ACC_ABSTRACT | JVM_ACC_FINAL);
353 }
354 
355 ModuleEntry* ObjArrayKlass::module() const {
356   assert(bottom_klass() != nullptr, "ObjArrayKlass returned unexpected null bottom_klass");
357   // The array is defined in the module of its bottom class
358   return bottom_klass()->module();
359 }
360 
361 PackageEntry* ObjArrayKlass::package() const {
362   assert(bottom_klass() != nullptr, "ObjArrayKlass returned unexpected null bottom_klass");
363   return bottom_klass()->package();
364 }
365 
366 // Printing
367 
368 void ObjArrayKlass::print_on(outputStream* st) const {
369 #ifndef PRODUCT
370   Klass::print_on(st);
371   st->print(" - instance klass: ");
372   element_klass()->print_value_on(st);
373   st->cr();
374 #endif //PRODUCT
375 }
376 
377 void ObjArrayKlass::print_value_on(outputStream* st) const {
378   assert(is_klass(), "must be klass");
379 
380   element_klass()->print_value_on(st);
381   st->print("[]");
382 }
383 
384 #ifndef PRODUCT
385 
386 void ObjArrayKlass::oop_print_on(oop obj, outputStream* st) {
387   ArrayKlass::oop_print_on(obj, st);
388   assert(obj->is_objArray(), "must be objArray");
389   objArrayOop oa = objArrayOop(obj);
390   int print_len = MIN2(oa->length(), MaxElementPrintSize);
391   for(int index = 0; index < print_len; index++) {
392     st->print(" - %3d : ", index);
393     if (oa->obj_at(index) != nullptr) {
394       oa->obj_at(index)->print_value_on(st);
395       st->cr();
396     } else {
397       st->print_cr("null");
398     }
399   }
400   int remaining = oa->length() - print_len;
401   if (remaining > 0) {
402     st->print_cr(" - <%d more elements, increase MaxElementPrintSize to print>", remaining);
403   }
404 }
405 
406 #endif //PRODUCT
407 
408 void ObjArrayKlass::oop_print_value_on(oop obj, outputStream* st) {
409   assert(obj->is_objArray(), "must be objArray");
410   st->print("a ");
411   element_klass()->print_value_on(st);
412   int len = objArrayOop(obj)->length();
413   st->print("[%d] ", len);
414   if (obj != nullptr) {
415     obj->print_address_on(st);
416   } else {
417     st->print_cr("null");
418   }
419 }
420 
421 const char* ObjArrayKlass::internal_name() const {
422   return external_name();
423 }
424 
425 
426 // Verification
427 
428 void ObjArrayKlass::verify_on(outputStream* st) {
429   ArrayKlass::verify_on(st);
430   guarantee(element_klass()->is_klass(), "should be klass");
431   guarantee(bottom_klass()->is_klass(), "should be klass");
432   Klass* bk = bottom_klass();
433   guarantee(bk->is_instance_klass() || bk->is_typeArray_klass(),  "invalid bottom klass");
434 }
435 
436 void ObjArrayKlass::oop_verify_on(oop obj, outputStream* st) {
437   ArrayKlass::oop_verify_on(obj, st);
438   guarantee(obj->is_objArray(), "must be objArray");
439   objArrayOop oa = objArrayOop(obj);
440   for(int index = 0; index < oa->length(); index++) {
441     guarantee(oopDesc::is_oop_or_null(oa->obj_at(index)), "should be oop");
442   }
443 }