1 /*
  2  * Copyright (c) 1997, 2024, 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 "precompiled.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/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/objArrayKlass.inline.hpp"
 41 #include "oops/objArrayOop.inline.hpp"
 42 #include "oops/oop.inline.hpp"
 43 #include "oops/symbol.hpp"
 44 #include "runtime/handles.inline.hpp"
 45 #include "runtime/mutexLocker.hpp"
 46 #include "utilities/macros.hpp"
 47 
 48 ObjArrayKlass* ObjArrayKlass::allocate(ClassLoaderData* loader_data, int n, Klass* k, Symbol* name, TRAPS) {
 49   assert(ObjArrayKlass::header_size() <= InstanceKlass::header_size(),
 50       "array klasses must be same size as InstanceKlass");
 51 
 52   int size = ArrayKlass::static_size(ObjArrayKlass::header_size());
 53 
 54   return new (loader_data, size, THREAD) ObjArrayKlass(n, k, name);
 55 }
 56 
 57 ObjArrayKlass* ObjArrayKlass::allocate_objArray_klass(ClassLoaderData* loader_data,
 58                                                       int n, Klass* element_klass, TRAPS) {
 59 
 60   // Eagerly allocate the direct array supertype.
 61   Klass* super_klass = nullptr;
 62   if (!Universe::is_bootstrapping() || vmClasses::Object_klass_loaded()) {
 63     assert(MultiArray_lock->holds_lock(THREAD), "must hold lock after bootstrapping");
 64     Klass* element_super = element_klass->super();
 65     if (element_super != nullptr) {
 66       // The element type has a direct super.  E.g., String[] has direct super of Object[].
 67       // Also, see if the element has secondary supertypes.
 68       // We need an array type for each before creating this array type.
 69       super_klass = element_super->array_klass(CHECK_NULL);
 70       const Array<Klass*>* element_supers = element_klass->secondary_supers();
 71       for (int i = element_supers->length() - 1; i >= 0; i--) {
 72         Klass* elem_super = element_supers->at(i);
 73         elem_super->array_klass(CHECK_NULL);
 74       }
 75       // Fall through because inheritance is acyclic and we hold the global recursive lock to allocate all the arrays.
 76     } else {
 77       // The element type is already Object.  Object[] has direct super of Object.
 78       super_klass = vmClasses::Object_klass();
 79     }
 80   }
 81 
 82   // Create type name for klass.
 83   Symbol* name = nullptr;
 84   {
 85     ResourceMark rm(THREAD);
 86     char *name_str = element_klass->name()->as_C_string();
 87     int len = element_klass->name()->utf8_length();
 88     char *new_str = NEW_RESOURCE_ARRAY(char, len + 4);
 89     int idx = 0;
 90     new_str[idx++] = JVM_SIGNATURE_ARRAY;
 91     if (element_klass->is_instance_klass()) { // it could be an array or simple type
 92       new_str[idx++] = JVM_SIGNATURE_CLASS;
 93     }
 94     memcpy(&new_str[idx], name_str, len * sizeof(char));
 95     idx += len;
 96     if (element_klass->is_instance_klass()) {
 97       new_str[idx++] = JVM_SIGNATURE_ENDCLASS;
 98     }
 99     new_str[idx++] = '\0';
100     name = SymbolTable::new_symbol(new_str);
101   }
102 
103   // Initialize instance variables
104   ObjArrayKlass* oak = ObjArrayKlass::allocate(loader_data, n, element_klass, name, CHECK_NULL);
105 
106   ModuleEntry* module = oak->module();
107   assert(module != nullptr, "No module entry for array");
108 
109   // Call complete_create_array_klass after all instance variables has been initialized.
110   ArrayKlass::complete_create_array_klass(oak, super_klass, module, CHECK_NULL);
111 
112   // Add all classes to our internal class loader list here,
113   // including classes in the bootstrap (null) class loader.
114   // Do this step after creating the mirror so that if the
115   // mirror creation fails, loaded_classes_do() doesn't find
116   // an array class without a mirror.
117   loader_data->add_class(oak);
118 
119   return oak;
120 }
121 
122 ObjArrayKlass::ObjArrayKlass(int n, Klass* element_klass, Symbol* name) : ArrayKlass(name, Kind) {
123   set_dimension(n);
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   assert(UseCompactObjectHeaders || obj->is_objArray(), "must be object array");
148   return objArrayOop(obj)->object_size();
149 }
150 
151 objArrayOop ObjArrayKlass::allocate(int length, TRAPS) {
152   check_array_allocation_length(length, arrayOopDesc::max_array_length(T_OBJECT), CHECK_NULL);
153   size_t size = objArrayOopDesc::object_size(length);
154   return (objArrayOop)Universe::heap()->array_allocate(this, size, length,
155                                                        /* do_zero */ true, THREAD);
156 }
157 
158 oop ObjArrayKlass::multi_allocate(int rank, jint* sizes, TRAPS) {
159   int length = *sizes;
160   ArrayKlass* ld_klass = lower_dimension();
161   // If length < 0 allocate will throw an exception.
162   objArrayOop array = allocate(length, CHECK_NULL);
163   objArrayHandle h_array (THREAD, array);
164   if (rank > 1) {
165     if (length != 0) {
166       for (int index = 0; index < length; index++) {
167         oop sub_array = ld_klass->multi_allocate(rank - 1, &sizes[1], CHECK_NULL);
168         h_array->obj_at_put(index, sub_array);
169       }
170     } else {
171       // Since this array dimension has zero length, nothing will be
172       // allocated, however the lower dimension values must be checked
173       // for illegal values.
174       for (int i = 0; i < rank - 1; ++i) {
175         sizes += 1;
176         if (*sizes < 0) {
177           THROW_MSG_0(vmSymbols::java_lang_NegativeArraySizeException(), err_msg("%d", *sizes));
178         }
179       }
180     }
181   }
182   return h_array();
183 }
184 
185 // Either oop or narrowOop depending on UseCompressedOops.
186 void ObjArrayKlass::do_copy(arrayOop s, size_t src_offset,
187                             arrayOop d, size_t dst_offset, int length, TRAPS) {
188   if (s == d) {
189     // since source and destination are equal we do not need conversion checks.
190     assert(length > 0, "sanity check");
191     ArrayAccess<>::oop_arraycopy(s, src_offset, d, dst_offset, length);
192   } else {
193     // We have to make sure all elements conform to the destination array
194     Klass* bound = ObjArrayKlass::cast(d->klass())->element_klass();
195     Klass* stype = ObjArrayKlass::cast(s->klass())->element_klass();
196     if (stype == bound || stype->is_subtype_of(bound)) {
197       // elements are guaranteed to be subtypes, so no check necessary
198       ArrayAccess<ARRAYCOPY_DISJOINT>::oop_arraycopy(s, src_offset, d, dst_offset, length);
199     } else {
200       // slow case: need individual subtype checks
201       // note: don't use obj_at_put below because it includes a redundant store check
202       if (!ArrayAccess<ARRAYCOPY_DISJOINT | ARRAYCOPY_CHECKCAST>::oop_arraycopy(s, src_offset, d, dst_offset, length)) {
203         ResourceMark rm(THREAD);
204         stringStream ss;
205         if (!bound->is_subtype_of(stype)) {
206           ss.print("arraycopy: type mismatch: can not copy %s[] into %s[]",
207                    stype->external_name(), bound->external_name());
208         } else {
209           // oop_arraycopy should return the index in the source array that
210           // contains the problematic oop.
211           ss.print("arraycopy: element type mismatch: can not cast one of the elements"
212                    " of %s[] to the type of the destination array, %s",
213                    stype->external_name(), bound->external_name());
214         }
215         THROW_MSG(vmSymbols::java_lang_ArrayStoreException(), ss.as_string());
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 (!d->is_objArray()) {
226     ResourceMark rm(THREAD);
227     stringStream ss;
228     if (d->is_typeArray()) {
229       ss.print("arraycopy: type mismatch: can not copy object array[] into %s[]",
230                type2name_tab[ArrayKlass::cast(d->klass())->element_type()]);
231     } else {
232       ss.print("arraycopy: destination type %s is not an array", d->klass()->external_name());
233     }
234     THROW_MSG(vmSymbols::java_lang_ArrayStoreException(), ss.as_string());
235   }
236 
237   // Check is all offsets and lengths are non negative
238   if (src_pos < 0 || dst_pos < 0 || length < 0) {
239     // Pass specific exception reason.
240     ResourceMark rm(THREAD);
241     stringStream ss;
242     if (src_pos < 0) {
243       ss.print("arraycopy: source index %d out of bounds for object array[%d]",
244                src_pos, s->length());
245     } else if (dst_pos < 0) {
246       ss.print("arraycopy: destination index %d out of bounds for object array[%d]",
247                dst_pos, d->length());
248     } else {
249       ss.print("arraycopy: length %d is negative", length);
250     }
251     THROW_MSG(vmSymbols::java_lang_ArrayIndexOutOfBoundsException(), ss.as_string());
252   }
253   // Check if the ranges are valid
254   if ((((unsigned int) length + (unsigned int) src_pos) > (unsigned int) s->length()) ||
255       (((unsigned int) length + (unsigned int) dst_pos) > (unsigned int) d->length())) {
256     // Pass specific exception reason.
257     ResourceMark rm(THREAD);
258     stringStream ss;
259     if (((unsigned int) length + (unsigned int) src_pos) > (unsigned int) s->length()) {
260       ss.print("arraycopy: last source index %u out of bounds for object array[%d]",
261                (unsigned int) length + (unsigned int) src_pos, s->length());
262     } else {
263       ss.print("arraycopy: last destination index %u out of bounds for object array[%d]",
264                (unsigned int) length + (unsigned int) dst_pos, d->length());
265     }
266     THROW_MSG(vmSymbols::java_lang_ArrayIndexOutOfBoundsException(), ss.as_string());
267   }
268 
269   // Special case. Boundary cases must be checked first
270   // This allows the following call: copy_array(s, s.length(), d.length(), 0).
271   // This is correct, since the position is supposed to be an 'in between point', i.e., s.length(),
272   // points to the right of the last element.
273   if (length==0) {
274     return;
275   }
276   if (UseCompressedOops) {
277     size_t src_offset = (size_t) objArrayOopDesc::obj_at_offset<narrowOop>(src_pos);
278     size_t dst_offset = (size_t) objArrayOopDesc::obj_at_offset<narrowOop>(dst_pos);
279     assert(arrayOopDesc::obj_offset_to_raw<narrowOop>(s, src_offset, nullptr) ==
280            objArrayOop(s)->obj_at_addr<narrowOop>(src_pos), "sanity");
281     assert(arrayOopDesc::obj_offset_to_raw<narrowOop>(d, dst_offset, nullptr) ==
282            objArrayOop(d)->obj_at_addr<narrowOop>(dst_pos), "sanity");
283     do_copy(s, src_offset, d, dst_offset, length, CHECK);
284   } else {
285     size_t src_offset = (size_t) objArrayOopDesc::obj_at_offset<oop>(src_pos);
286     size_t dst_offset = (size_t) objArrayOopDesc::obj_at_offset<oop>(dst_pos);
287     assert(arrayOopDesc::obj_offset_to_raw<oop>(s, src_offset, nullptr) ==
288            objArrayOop(s)->obj_at_addr<oop>(src_pos), "sanity");
289     assert(arrayOopDesc::obj_offset_to_raw<oop>(d, dst_offset, nullptr) ==
290            objArrayOop(d)->obj_at_addr<oop>(dst_pos), "sanity");
291     do_copy(s, src_offset, d, dst_offset, length, CHECK);
292   }
293 }
294 
295 bool ObjArrayKlass::can_be_primary_super_slow() const {
296   if (!bottom_klass()->can_be_primary_super())
297     // array of interfaces
298     return false;
299   else
300     return Klass::can_be_primary_super_slow();
301 }
302 
303 GrowableArray<Klass*>* ObjArrayKlass::compute_secondary_supers(int num_extra_slots,
304                                                                Array<InstanceKlass*>* transitive_interfaces) {
305   assert(transitive_interfaces == nullptr, "sanity");
306   // interfaces = { cloneable_klass, serializable_klass, elemSuper[], ... };
307   const Array<Klass*>* elem_supers = element_klass()->secondary_supers();
308   int num_elem_supers = elem_supers == nullptr ? 0 : elem_supers->length();
309   int num_secondaries = num_extra_slots + 2 + num_elem_supers;
310   if (num_secondaries == 2) {
311     // Must share this for correct bootstrapping!
312     set_secondary_supers(Universe::the_array_interfaces_array(),
313                          Universe::the_array_interfaces_bitmap());
314     return nullptr;
315   } else {
316     GrowableArray<Klass*>* secondaries = new GrowableArray<Klass*>(num_elem_supers+2);
317     secondaries->push(vmClasses::Cloneable_klass());
318     secondaries->push(vmClasses::Serializable_klass());
319     for (int i = 0; i < num_elem_supers; i++) {
320       Klass* elem_super = elem_supers->at(i);
321       Klass* array_super = elem_super->array_klass_or_null();
322       assert(array_super != nullptr, "must already have been created");
323       secondaries->push(array_super);
324     }
325     return secondaries;
326   }
327 }
328 
329 void ObjArrayKlass::initialize(TRAPS) {
330   bottom_klass()->initialize(THREAD);  // dispatches to either InstanceKlass or TypeArrayKlass
331 }
332 
333 void ObjArrayKlass::metaspace_pointers_do(MetaspaceClosure* it) {
334   ArrayKlass::metaspace_pointers_do(it);
335   it->push(&_element_klass);
336   it->push(&_bottom_klass);
337 }
338 
339 jint ObjArrayKlass::compute_modifier_flags() const {
340   // The modifier for an objectArray is the same as its element
341   if (element_klass() == nullptr) {
342     assert(Universe::is_bootstrapping(), "partial objArray only at startup");
343     return JVM_ACC_ABSTRACT | JVM_ACC_FINAL | JVM_ACC_PUBLIC;
344   }
345   // Return the flags of the bottom element type.
346   jint element_flags = bottom_klass()->compute_modifier_flags();
347 
348   return (element_flags & (JVM_ACC_PUBLIC | JVM_ACC_PRIVATE | JVM_ACC_PROTECTED))
349                         | (JVM_ACC_ABSTRACT | JVM_ACC_FINAL);
350 }
351 
352 ModuleEntry* ObjArrayKlass::module() const {
353   assert(bottom_klass() != nullptr, "ObjArrayKlass returned unexpected null bottom_klass");
354   // The array is defined in the module of its bottom class
355   return bottom_klass()->module();
356 }
357 
358 PackageEntry* ObjArrayKlass::package() const {
359   assert(bottom_klass() != nullptr, "ObjArrayKlass returned unexpected null bottom_klass");
360   return bottom_klass()->package();
361 }
362 
363 // Printing
364 
365 void ObjArrayKlass::print_on(outputStream* st) const {
366 #ifndef PRODUCT
367   Klass::print_on(st);
368   st->print(" - instance klass: ");
369   element_klass()->print_value_on(st);
370   st->cr();
371 #endif //PRODUCT
372 }
373 
374 void ObjArrayKlass::print_value_on(outputStream* st) const {
375   assert(is_klass(), "must be klass");
376 
377   element_klass()->print_value_on(st);
378   st->print("[]");
379 }
380 
381 #ifndef PRODUCT
382 
383 void ObjArrayKlass::oop_print_on(oop obj, outputStream* st) {
384   ArrayKlass::oop_print_on(obj, st);
385   assert(obj->is_objArray(), "must be objArray");
386   objArrayOop oa = objArrayOop(obj);
387   int print_len = MIN2(oa->length(), MaxElementPrintSize);
388   for(int index = 0; index < print_len; index++) {
389     st->print(" - %3d : ", index);
390     if (oa->obj_at(index) != nullptr) {
391       oa->obj_at(index)->print_value_on(st);
392       st->cr();
393     } else {
394       st->print_cr("null");
395     }
396   }
397   int remaining = oa->length() - print_len;
398   if (remaining > 0) {
399     st->print_cr(" - <%d more elements, increase MaxElementPrintSize to print>", remaining);
400   }
401 }
402 
403 #endif //PRODUCT
404 
405 void ObjArrayKlass::oop_print_value_on(oop obj, outputStream* st) {
406   assert(obj->is_objArray(), "must be objArray");
407   st->print("a ");
408   element_klass()->print_value_on(st);
409   int len = objArrayOop(obj)->length();
410   st->print("[%d] ", len);
411   if (obj != nullptr) {
412     obj->print_address_on(st);
413   } else {
414     st->print_cr("null");
415   }
416 }
417 
418 const char* ObjArrayKlass::internal_name() const {
419   return external_name();
420 }
421 
422 
423 // Verification
424 
425 void ObjArrayKlass::verify_on(outputStream* st) {
426   ArrayKlass::verify_on(st);
427   guarantee(element_klass()->is_klass(), "should be klass");
428   guarantee(bottom_klass()->is_klass(), "should be klass");
429   Klass* bk = bottom_klass();
430   guarantee(bk->is_instance_klass() || bk->is_typeArray_klass(),  "invalid bottom klass");
431 }
432 
433 void ObjArrayKlass::oop_verify_on(oop obj, outputStream* st) {
434   ArrayKlass::oop_verify_on(obj, st);
435   guarantee(obj->is_objArray(), "must be objArray");
436   objArrayOop oa = objArrayOop(obj);
437   for(int index = 0; index < oa->length(); index++) {
438     guarantee(oopDesc::is_oop_or_null(oa->obj_at(index)), "should be oop");
439   }
440 }