1 /*
  2  * Copyright (c) 1997, 2021, 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.inline.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 = NULL;
 62   if (!Universe::is_bootstrapping() || vmClasses::Object_klass_loaded()) {
 63     Klass* element_super = element_klass->super();
 64     if (element_super != NULL) {
 65       // The element type has a direct super.  E.g., String[] has direct super of Object[].
 66       super_klass = element_super->array_klass_or_null();
 67       bool supers_exist = super_klass != NULL;
 68       // Also, see if the element has secondary supertypes.
 69       // We need an array type for each.
 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         if (elem_super->array_klass_or_null() == NULL) {
 74           supers_exist = false;
 75           break;
 76         }
 77       }
 78       if (!supers_exist) {
 79         // Oops.  Not allocated yet.  Back out, allocate it, and retry.
 80         Klass* ek = NULL;
 81         {
 82           MutexUnlocker mu(MultiArray_lock);
 83           super_klass = element_super->array_klass(CHECK_NULL);
 84           for( int i = element_supers->length()-1; i >= 0; i-- ) {
 85             Klass* elem_super = element_supers->at(i);
 86             elem_super->array_klass(CHECK_NULL);
 87           }
 88           // Now retry from the beginning
 89           ek = element_klass->array_klass(n, CHECK_NULL);
 90         }  // re-lock
 91         return ObjArrayKlass::cast(ek);
 92       }
 93     } else {
 94       // The element type is already Object.  Object[] has direct super of Object.
 95       super_klass = vmClasses::Object_klass();
 96     }
 97   }
 98 
 99   // Create type name for klass.
100   Symbol* name = NULL;
101   {
102     ResourceMark rm(THREAD);
103     char *name_str = element_klass->name()->as_C_string();
104     int len = element_klass->name()->utf8_length();
105     char *new_str = NEW_RESOURCE_ARRAY(char, len + 4);
106     int idx = 0;
107     new_str[idx++] = JVM_SIGNATURE_ARRAY;
108     if (element_klass->is_instance_klass()) { // it could be an array or simple type
109       new_str[idx++] = JVM_SIGNATURE_CLASS;
110     }
111     memcpy(&new_str[idx], name_str, len * sizeof(char));
112     idx += len;
113     if (element_klass->is_instance_klass()) {
114       new_str[idx++] = JVM_SIGNATURE_ENDCLASS;
115     }
116     new_str[idx++] = '\0';
117     name = SymbolTable::new_symbol(new_str);
118   }
119 
120   // Initialize instance variables
121   ObjArrayKlass* oak = ObjArrayKlass::allocate(loader_data, n, element_klass, name, CHECK_NULL);
122 
123   ModuleEntry* module = oak->module();
124   assert(module != NULL, "No module entry for array");
125 
126   // Call complete_create_array_klass after all instance variables has been initialized.
127   ArrayKlass::complete_create_array_klass(oak, super_klass, module, CHECK_NULL);
128 
129   // Add all classes to our internal class loader list here,
130   // including classes in the bootstrap (NULL) class loader.
131   // Do this step after creating the mirror so that if the
132   // mirror creation fails, loaded_classes_do() doesn't find
133   // an array class without a mirror.
134   loader_data->add_class(oak);
135 
136   return oak;
137 }
138 
139 ObjArrayKlass::ObjArrayKlass(int n, Klass* element_klass, Symbol* name) : ArrayKlass(name, ID) {
140   set_dimension(n);
141   set_element_klass(element_klass);
142 
143   Klass* bk;
144   if (element_klass->is_objArray_klass()) {
145     bk = ObjArrayKlass::cast(element_klass)->bottom_klass();
146   } else {
147     bk = element_klass;
148   }
149   assert(bk != NULL && (bk->is_instance_klass() || bk->is_typeArray_klass()), "invalid bottom klass");
150   set_bottom_klass(bk);
151   set_class_loader_data(bk->class_loader_data());
152 
153   set_layout_helper(array_layout_helper(T_OBJECT));
154   assert(is_array_klass(), "sanity");
155   assert(is_objArray_klass(), "sanity");
156 }
157 
158 size_t ObjArrayKlass::oop_size(oop obj) const {
159   return objArrayOop(obj)->object_size();
160 }
161 
162 objArrayOop ObjArrayKlass::allocate(int length, TRAPS) {
163   check_array_allocation_length(length, arrayOopDesc::max_array_length(T_OBJECT), CHECK_NULL);
164   size_t size = objArrayOopDesc::object_size(length);
165   return (objArrayOop)Universe::heap()->array_allocate(this, size, length,
166                                                        /* do_zero */ true, THREAD);
167 }
168 
169 oop ObjArrayKlass::multi_allocate(int rank, jint* sizes, TRAPS) {
170   int length = *sizes;
171   // Call to lower_dimension uses this pointer, so most be called before a
172   // possible GC
173   Klass* ld_klass = lower_dimension();
174   // If length < 0 allocate will throw an exception.
175   objArrayOop array = allocate(length, CHECK_NULL);
176   objArrayHandle h_array (THREAD, array);
177   if (rank > 1) {
178     if (length != 0) {
179       for (int index = 0; index < length; index++) {
180         ArrayKlass* ak = ArrayKlass::cast(ld_klass);
181         oop sub_array = ak->multi_allocate(rank-1, &sizes[1], CHECK_NULL);
182         h_array->obj_at_put(index, sub_array);
183       }
184     } else {
185       // Since this array dimension has zero length, nothing will be
186       // allocated, however the lower dimension values must be checked
187       // for illegal values.
188       for (int i = 0; i < rank - 1; ++i) {
189         sizes += 1;
190         if (*sizes < 0) {
191           THROW_MSG_0(vmSymbols::java_lang_NegativeArraySizeException(), err_msg("%d", *sizes));
192         }
193       }
194     }
195   }
196   return h_array();
197 }
198 
199 // Either oop or narrowOop depending on UseCompressedOops.
200 void ObjArrayKlass::do_copy(arrayOop s, size_t src_offset,
201                             arrayOop d, size_t dst_offset, int length, TRAPS) {
202   if (s == d) {
203     // since source and destination are equal we do not need conversion checks.
204     assert(length > 0, "sanity check");
205     ArrayAccess<>::oop_arraycopy(s, src_offset, d, dst_offset, length);
206   } else {
207     // We have to make sure all elements conform to the destination array
208     Klass* bound = ObjArrayKlass::cast(d->klass())->element_klass();
209     Klass* stype = ObjArrayKlass::cast(s->klass())->element_klass();
210     if (stype == bound || stype->is_subtype_of(bound)) {
211       // elements are guaranteed to be subtypes, so no check necessary
212       ArrayAccess<ARRAYCOPY_DISJOINT>::oop_arraycopy(s, src_offset, d, dst_offset, length);
213     } else {
214       // slow case: need individual subtype checks
215       // note: don't use obj_at_put below because it includes a redundant store check
216       if (!ArrayAccess<ARRAYCOPY_DISJOINT | ARRAYCOPY_CHECKCAST>::oop_arraycopy(s, src_offset, d, dst_offset, length)) {
217         ResourceMark rm(THREAD);
218         stringStream ss;
219         if (!bound->is_subtype_of(stype)) {
220           ss.print("arraycopy: type mismatch: can not copy %s[] into %s[]",
221                    stype->external_name(), bound->external_name());
222         } else {
223           // oop_arraycopy should return the index in the source array that
224           // contains the problematic oop.
225           ss.print("arraycopy: element type mismatch: can not cast one of the elements"
226                    " of %s[] to the type of the destination array, %s",
227                    stype->external_name(), bound->external_name());
228         }
229         THROW_MSG(vmSymbols::java_lang_ArrayStoreException(), ss.as_string());
230       }
231     }
232   }
233 }
234 
235 void ObjArrayKlass::copy_array(arrayOop s, int src_pos, arrayOop d,
236                                int dst_pos, int length, TRAPS) {
237   assert(s->is_objArray(), "must be obj array");
238 
239   if (!d->is_objArray()) {
240     ResourceMark rm(THREAD);
241     stringStream ss;
242     if (d->is_typeArray()) {
243       ss.print("arraycopy: type mismatch: can not copy object array[] into %s[]",
244                type2name_tab[ArrayKlass::cast(d->klass())->element_type()]);
245     } else {
246       ss.print("arraycopy: destination type %s is not an array", d->klass()->external_name());
247     }
248     THROW_MSG(vmSymbols::java_lang_ArrayStoreException(), ss.as_string());
249   }
250 
251   // Check is all offsets and lengths are non negative
252   if (src_pos < 0 || dst_pos < 0 || length < 0) {
253     // Pass specific exception reason.
254     ResourceMark rm(THREAD);
255     stringStream ss;
256     if (src_pos < 0) {
257       ss.print("arraycopy: source index %d out of bounds for object array[%d]",
258                src_pos, s->length());
259     } else if (dst_pos < 0) {
260       ss.print("arraycopy: destination index %d out of bounds for object array[%d]",
261                dst_pos, d->length());
262     } else {
263       ss.print("arraycopy: length %d is negative", length);
264     }
265     THROW_MSG(vmSymbols::java_lang_ArrayIndexOutOfBoundsException(), ss.as_string());
266   }
267   // Check if the ranges are valid
268   if ((((unsigned int) length + (unsigned int) src_pos) > (unsigned int) s->length()) ||
269       (((unsigned int) length + (unsigned int) dst_pos) > (unsigned int) d->length())) {
270     // Pass specific exception reason.
271     ResourceMark rm(THREAD);
272     stringStream ss;
273     if (((unsigned int) length + (unsigned int) src_pos) > (unsigned int) s->length()) {
274       ss.print("arraycopy: last source index %u out of bounds for object array[%d]",
275                (unsigned int) length + (unsigned int) src_pos, s->length());
276     } else {
277       ss.print("arraycopy: last destination index %u out of bounds for object array[%d]",
278                (unsigned int) length + (unsigned int) dst_pos, d->length());
279     }
280     THROW_MSG(vmSymbols::java_lang_ArrayIndexOutOfBoundsException(), ss.as_string());
281   }
282 
283   // Special case. Boundary cases must be checked first
284   // This allows the following call: copy_array(s, s.length(), d.length(), 0).
285   // This is correct, since the position is supposed to be an 'in between point', i.e., s.length(),
286   // points to the right of the last element.
287   if (length==0) {
288     return;
289   }
290   if (UseCompressedOops) {
291     size_t src_offset = (size_t) objArrayOopDesc::obj_at_offset<narrowOop>(src_pos);
292     size_t dst_offset = (size_t) objArrayOopDesc::obj_at_offset<narrowOop>(dst_pos);
293     assert(arrayOopDesc::obj_offset_to_raw<narrowOop>(s, src_offset, NULL) ==
294            objArrayOop(s)->obj_at_addr<narrowOop>(src_pos), "sanity");
295     assert(arrayOopDesc::obj_offset_to_raw<narrowOop>(d, dst_offset, NULL) ==
296            objArrayOop(d)->obj_at_addr<narrowOop>(dst_pos), "sanity");
297     do_copy(s, src_offset, d, dst_offset, length, CHECK);
298   } else {
299     size_t src_offset = (size_t) objArrayOopDesc::obj_at_offset<oop>(src_pos);
300     size_t dst_offset = (size_t) objArrayOopDesc::obj_at_offset<oop>(dst_pos);
301     assert(arrayOopDesc::obj_offset_to_raw<oop>(s, src_offset, NULL) ==
302            objArrayOop(s)->obj_at_addr<oop>(src_pos), "sanity");
303     assert(arrayOopDesc::obj_offset_to_raw<oop>(d, dst_offset, NULL) ==
304            objArrayOop(d)->obj_at_addr<oop>(dst_pos), "sanity");
305     do_copy(s, src_offset, d, dst_offset, length, CHECK);
306   }
307 }
308 
309 
310 Klass* ObjArrayKlass::array_klass(int n, TRAPS) {
311 
312   assert(dimension() <= n, "check order of chain");
313   int dim = dimension();
314   if (dim == n) return this;
315 
316   // lock-free read needs acquire semantics
317   if (higher_dimension_acquire() == NULL) {
318 
319     ResourceMark rm(THREAD);
320     {
321       // Ensure atomic creation of higher dimensions
322       MutexLocker mu(THREAD, MultiArray_lock);
323 
324       // Check if another thread beat us
325       if (higher_dimension() == NULL) {
326 
327         // Create multi-dim klass object and link them together
328         Klass* k =
329           ObjArrayKlass::allocate_objArray_klass(class_loader_data(), dim + 1, this, CHECK_NULL);
330         ObjArrayKlass* ak = ObjArrayKlass::cast(k);
331         ak->set_lower_dimension(this);
332         // use 'release' to pair with lock-free load
333         release_set_higher_dimension(ak);
334         assert(ak->is_objArray_klass(), "incorrect initialization of ObjArrayKlass");
335       }
336     }
337   }
338 
339   ObjArrayKlass *ak = ObjArrayKlass::cast(higher_dimension());
340   THREAD->check_possible_safepoint();
341   return ak->array_klass(n, THREAD);
342 }
343 
344 Klass* ObjArrayKlass::array_klass_or_null(int n) {
345 
346   assert(dimension() <= n, "check order of chain");
347   int dim = dimension();
348   if (dim == n) return this;
349 
350   // lock-free read needs acquire semantics
351   if (higher_dimension_acquire() == NULL) {
352     return NULL;
353   }
354 
355   ObjArrayKlass *ak = ObjArrayKlass::cast(higher_dimension());
356   return ak->array_klass_or_null(n);
357 }
358 
359 Klass* ObjArrayKlass::array_klass(TRAPS) {
360   return array_klass(dimension() +  1, THREAD);
361 }
362 
363 Klass* ObjArrayKlass::array_klass_or_null() {
364   return array_klass_or_null(dimension() +  1);
365 }
366 
367 bool ObjArrayKlass::can_be_primary_super_slow() const {
368   if (!bottom_klass()->can_be_primary_super())
369     // array of interfaces
370     return false;
371   else
372     return Klass::can_be_primary_super_slow();
373 }
374 
375 GrowableArray<Klass*>* ObjArrayKlass::compute_secondary_supers(int num_extra_slots,
376                                                                Array<InstanceKlass*>* transitive_interfaces) {
377   assert(transitive_interfaces == NULL, "sanity");
378   // interfaces = { cloneable_klass, serializable_klass, elemSuper[], ... };
379   const Array<Klass*>* elem_supers = element_klass()->secondary_supers();
380   int num_elem_supers = elem_supers == NULL ? 0 : elem_supers->length();
381   int num_secondaries = num_extra_slots + 2 + num_elem_supers;
382   if (num_secondaries == 2) {
383     // Must share this for correct bootstrapping!
384     set_secondary_supers(Universe::the_array_interfaces_array());
385     return NULL;
386   } else {
387     GrowableArray<Klass*>* secondaries = new GrowableArray<Klass*>(num_elem_supers+2);
388     secondaries->push(vmClasses::Cloneable_klass());
389     secondaries->push(vmClasses::Serializable_klass());
390     for (int i = 0; i < num_elem_supers; i++) {
391       Klass* elem_super = elem_supers->at(i);
392       Klass* array_super = elem_super->array_klass_or_null();
393       assert(array_super != NULL, "must already have been created");
394       secondaries->push(array_super);
395     }
396     return secondaries;
397   }
398 }
399 
400 void ObjArrayKlass::initialize(TRAPS) {
401   bottom_klass()->initialize(THREAD);  // dispatches to either InstanceKlass or TypeArrayKlass
402 }
403 
404 void ObjArrayKlass::metaspace_pointers_do(MetaspaceClosure* it) {
405   ArrayKlass::metaspace_pointers_do(it);
406   it->push(&_element_klass);
407   it->push(&_bottom_klass);
408 }
409 
410 jint ObjArrayKlass::compute_modifier_flags() const {
411   // The modifier for an objectArray is the same as its element
412   if (element_klass() == NULL) {
413     assert(Universe::is_bootstrapping(), "partial objArray only at startup");
414     return JVM_ACC_ABSTRACT | JVM_ACC_FINAL | JVM_ACC_PUBLIC;
415   }
416   // Return the flags of the bottom element type.
417   jint element_flags = bottom_klass()->compute_modifier_flags();
418 
419   return (element_flags & (JVM_ACC_PUBLIC | JVM_ACC_PRIVATE | JVM_ACC_PROTECTED))
420                         | (JVM_ACC_ABSTRACT | JVM_ACC_FINAL);
421 }
422 
423 ModuleEntry* ObjArrayKlass::module() const {
424   assert(bottom_klass() != NULL, "ObjArrayKlass returned unexpected NULL bottom_klass");
425   // The array is defined in the module of its bottom class
426   return bottom_klass()->module();
427 }
428 
429 PackageEntry* ObjArrayKlass::package() const {
430   assert(bottom_klass() != NULL, "ObjArrayKlass returned unexpected NULL bottom_klass");
431   return bottom_klass()->package();
432 }
433 
434 // Printing
435 
436 void ObjArrayKlass::print_on(outputStream* st) const {
437 #ifndef PRODUCT
438   Klass::print_on(st);
439   st->print(" - instance klass: ");
440   element_klass()->print_value_on(st);
441   st->cr();
442 #endif //PRODUCT
443 }
444 
445 void ObjArrayKlass::print_value_on(outputStream* st) const {
446   assert(is_klass(), "must be klass");
447 
448   element_klass()->print_value_on(st);
449   st->print("[]");
450 }
451 
452 #ifndef PRODUCT
453 
454 void ObjArrayKlass::oop_print_on(oop obj, outputStream* st) {
455   ArrayKlass::oop_print_on(obj, st);
456   assert(obj->is_objArray(), "must be objArray");
457   objArrayOop oa = objArrayOop(obj);
458   int print_len = MIN2((intx) oa->length(), MaxElementPrintSize);
459   for(int index = 0; index < print_len; index++) {
460     st->print(" - %3d : ", index);
461     if (oa->obj_at(index) != NULL) {
462       oa->obj_at(index)->print_value_on(st);
463       st->cr();
464     } else {
465       st->print_cr("NULL");
466     }
467   }
468   int remaining = oa->length() - print_len;
469   if (remaining > 0) {
470     st->print_cr(" - <%d more elements, increase MaxElementPrintSize to print>", remaining);
471   }
472 }
473 
474 #endif //PRODUCT
475 
476 void ObjArrayKlass::oop_print_value_on(oop obj, outputStream* st) {
477   assert(obj->is_objArray(), "must be objArray");
478   st->print("a ");
479   element_klass()->print_value_on(st);
480   int len = objArrayOop(obj)->length();
481   st->print("[%d] ", len);
482   if (obj != NULL) {
483     obj->print_address_on(st);
484   } else {
485     st->print_cr("NULL");
486   }
487 }
488 
489 const char* ObjArrayKlass::internal_name() const {
490   return external_name();
491 }
492 
493 
494 // Verification
495 
496 void ObjArrayKlass::verify_on(outputStream* st) {
497   ArrayKlass::verify_on(st);
498   guarantee(element_klass()->is_klass(), "should be klass");
499   guarantee(bottom_klass()->is_klass(), "should be klass");
500   Klass* bk = bottom_klass();
501   guarantee(bk->is_instance_klass() || bk->is_typeArray_klass(),  "invalid bottom klass");
502 }
503 
504 void ObjArrayKlass::oop_verify_on(oop obj, outputStream* st) {
505   ArrayKlass::oop_verify_on(obj, st);
506   guarantee(obj->is_objArray(), "must be objArray");
507   objArrayOop oa = objArrayOop(obj);
508   for(int index = 0; index < oa->length(); index++) {
509     guarantee(oopDesc::is_oop_or_null(oa->obj_at(index)), "should be oop");
510   }
511 }