1 /*
   2  * Copyright (c) 1997, 2019, 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/systemDictionary.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 Klass* 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() || SystemDictionary::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_0);
  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_0);
  87           }
  88           // Now retry from the beginning
  89           ek = element_klass->array_klass(n, CHECK_0);
  90         }  // re-lock
  91         return ek;
  92       }
  93     } else {
  94       // The element type is already Object.  Object[] has direct super of Object.
  95       super_klass = SystemDictionary::Object_klass();
  96     }
  97   }
  98 
  99   // Create type name for klass.
 100   Symbol* name = NULL;
 101   if (!element_klass->is_instance_klass() ||
 102       (name = InstanceKlass::cast(element_klass)->array_name()) == NULL) {
 103 
 104     ResourceMark rm(THREAD);
 105     char *name_str = element_klass->name()->as_C_string();
 106     int len = element_klass->name()->utf8_length();
 107     char *new_str = NEW_RESOURCE_ARRAY(char, len + 4);
 108     int idx = 0;
 109     new_str[idx++] = '[';
 110     if (element_klass->is_instance_klass()) { // it could be an array or simple type
 111       new_str[idx++] = 'L';
 112     }
 113     memcpy(&new_str[idx], name_str, len * sizeof(char));
 114     idx += len;
 115     if (element_klass->is_instance_klass()) {
 116       new_str[idx++] = ';';
 117     }
 118     new_str[idx++] = '\0';
 119     name = SymbolTable::new_permanent_symbol(new_str);
 120     if (element_klass->is_instance_klass()) {
 121       InstanceKlass* ik = InstanceKlass::cast(element_klass);
 122       ik->set_array_name(name);
 123     }
 124   }
 125 
 126   // Initialize instance variables
 127   ObjArrayKlass* oak = ObjArrayKlass::allocate(loader_data, n, element_klass, name, CHECK_0);
 128 
 129   ModuleEntry* module = oak->module();
 130   assert(module != NULL, "No module entry for array");
 131 
 132   // Call complete_create_array_klass after all instance variables has been initialized.
 133   ArrayKlass::complete_create_array_klass(oak, super_klass, module, CHECK_0);
 134 
 135   // Add all classes to our internal class loader list here,
 136   // including classes in the bootstrap (NULL) class loader.
 137   // Do this step after creating the mirror so that if the
 138   // mirror creation fails, loaded_classes_do() doesn't find
 139   // an array class without a mirror.
 140   loader_data->add_class(oak);
 141 
 142   return oak;
 143 }
 144 
 145 ObjArrayKlass::ObjArrayKlass(int n, Klass* element_klass, Symbol* name) : ArrayKlass(name, ID) {
 146   this->set_dimension(n);
 147   this->set_element_klass(element_klass);
 148   // decrement refcount because object arrays are not explicitly freed.  The
 149   // InstanceKlass array_name() keeps the name counted while the klass is
 150   // loaded.
 151   name->decrement_refcount();
 152 
 153   Klass* bk;
 154   if (element_klass->is_objArray_klass()) {
 155     bk = ObjArrayKlass::cast(element_klass)->bottom_klass();
 156   } else {
 157     bk = element_klass;
 158   }
 159   assert(bk != NULL && (bk->is_instance_klass() || bk->is_typeArray_klass()), "invalid bottom klass");
 160   this->set_bottom_klass(bk);
 161   this->set_class_loader_data(bk->class_loader_data());
 162 
 163   this->set_layout_helper(array_layout_helper(T_OBJECT));
 164   assert(this->is_array_klass(), "sanity");
 165   assert(this->is_objArray_klass(), "sanity");
 166 }
 167 
 168 int ObjArrayKlass::oop_size(oop obj) const {
 169   assert(obj->is_objArray(), "must be object array");
 170   return objArrayOop(obj)->object_size();
 171 }
 172 
 173 objArrayOop ObjArrayKlass::allocate(int length, TRAPS) {
 174   check_array_allocation_length(length, arrayOopDesc::max_array_length(T_OBJECT), CHECK_0);
 175   int size = objArrayOopDesc::object_size(length);
 176   return (objArrayOop)Universe::heap()->array_allocate(this, size, length,
 177                                                        /* do_zero */ true, THREAD);
 178 }
 179 
 180 static int multi_alloc_counter = 0;
 181 
 182 oop ObjArrayKlass::multi_allocate(int rank, jint* sizes, TRAPS) {
 183   int length = *sizes;
 184   // Call to lower_dimension uses this pointer, so most be called before a
 185   // possible GC
 186   Klass* ld_klass = lower_dimension();
 187   // If length < 0 allocate will throw an exception.
 188   objArrayOop array = allocate(length, CHECK_NULL);
 189   objArrayHandle h_array (THREAD, array);
 190   if (rank > 1) {
 191     if (length != 0) {
 192       for (int index = 0; index < length; index++) {
 193         ArrayKlass* ak = ArrayKlass::cast(ld_klass);
 194         oop sub_array = ak->multi_allocate(rank-1, &sizes[1], CHECK_NULL);
 195         h_array->obj_at_put(index, sub_array);
 196       }
 197     } else {
 198       // Since this array dimension has zero length, nothing will be
 199       // allocated, however the lower dimension values must be checked
 200       // for illegal values.
 201       for (int i = 0; i < rank - 1; ++i) {
 202         sizes += 1;
 203         if (*sizes < 0) {
 204           THROW_MSG_0(vmSymbols::java_lang_NegativeArraySizeException(), err_msg("%d", *sizes));
 205         }
 206       }
 207     }
 208   }
 209   return h_array();
 210 }
 211 
 212 // Either oop or narrowOop depending on UseCompressedOops.
 213 void ObjArrayKlass::do_copy(arrayOop s, size_t src_offset,
 214                             arrayOop d, size_t dst_offset, int length, TRAPS) {
 215   if (oopDesc::equals(s, d)) {
 216     // since source and destination are equal we do not need conversion checks.
 217     assert(length > 0, "sanity check");
 218     ArrayAccess<>::oop_arraycopy(s, src_offset, d, dst_offset, length);
 219   } else {
 220     // We have to make sure all elements conform to the destination array
 221     Klass* bound = ObjArrayKlass::cast(d->klass())->element_klass();
 222     Klass* stype = ObjArrayKlass::cast(s->klass())->element_klass();
 223     if (stype == bound || stype->is_subtype_of(bound)) {
 224       // elements are guaranteed to be subtypes, so no check necessary
 225       ArrayAccess<ARRAYCOPY_DISJOINT>::oop_arraycopy(s, src_offset, d, dst_offset, length);
 226     } else {
 227       // slow case: need individual subtype checks
 228       // note: don't use obj_at_put below because it includes a redundant store check
 229       if (!ArrayAccess<ARRAYCOPY_DISJOINT | ARRAYCOPY_CHECKCAST>::oop_arraycopy(s, src_offset, d, dst_offset, length)) {
 230         ResourceMark rm(THREAD);
 231         stringStream ss;
 232         if (!bound->is_subtype_of(stype)) {
 233           ss.print("arraycopy: type mismatch: can not copy %s[] into %s[]",
 234                    stype->external_name(), bound->external_name());
 235         } else {
 236           // oop_arraycopy should return the index in the source array that
 237           // contains the problematic oop.
 238           ss.print("arraycopy: element type mismatch: can not cast one of the elements"
 239                    " of %s[] to the type of the destination array, %s",
 240                    stype->external_name(), bound->external_name());
 241         }
 242         THROW_MSG(vmSymbols::java_lang_ArrayStoreException(), ss.as_string());
 243       }
 244     }
 245   }
 246 }
 247 
 248 void ObjArrayKlass::copy_array(arrayOop s, int src_pos, arrayOop d,
 249                                int dst_pos, int length, TRAPS) {
 250   assert(s->is_objArray(), "must be obj array");
 251 
 252   if (!d->is_objArray()) {
 253     ResourceMark rm(THREAD);
 254     stringStream ss;
 255     if (d->is_typeArray()) {
 256       ss.print("arraycopy: type mismatch: can not copy object array[] into %s[]",
 257                type2name_tab[ArrayKlass::cast(d->klass())->element_type()]);
 258     } else {
 259       ss.print("arraycopy: destination type %s is not an array", d->klass()->external_name());
 260     }
 261     THROW_MSG(vmSymbols::java_lang_ArrayStoreException(), ss.as_string());
 262   }
 263 
 264   // Check is all offsets and lengths are non negative
 265   if (src_pos < 0 || dst_pos < 0 || length < 0) {
 266     // Pass specific exception reason.
 267     ResourceMark rm(THREAD);
 268     stringStream ss;
 269     if (src_pos < 0) {
 270       ss.print("arraycopy: source index %d out of bounds for object array[%d]",
 271                src_pos, s->length());
 272     } else if (dst_pos < 0) {
 273       ss.print("arraycopy: destination index %d out of bounds for object array[%d]",
 274                dst_pos, d->length());
 275     } else {
 276       ss.print("arraycopy: length %d is negative", length);
 277     }
 278     THROW_MSG(vmSymbols::java_lang_ArrayIndexOutOfBoundsException(), ss.as_string());
 279   }
 280   // Check if the ranges are valid
 281   if ((((unsigned int) length + (unsigned int) src_pos) > (unsigned int) s->length()) ||
 282       (((unsigned int) length + (unsigned int) dst_pos) > (unsigned int) d->length())) {
 283     // Pass specific exception reason.
 284     ResourceMark rm(THREAD);
 285     stringStream ss;
 286     if (((unsigned int) length + (unsigned int) src_pos) > (unsigned int) s->length()) {
 287       ss.print("arraycopy: last source index %u out of bounds for object array[%d]",
 288                (unsigned int) length + (unsigned int) src_pos, s->length());
 289     } else {
 290       ss.print("arraycopy: last destination index %u out of bounds for object array[%d]",
 291                (unsigned int) length + (unsigned int) dst_pos, d->length());
 292     }
 293     THROW_MSG(vmSymbols::java_lang_ArrayIndexOutOfBoundsException(), ss.as_string());
 294   }
 295 
 296   // Special case. Boundary cases must be checked first
 297   // This allows the following call: copy_array(s, s.length(), d.length(), 0).
 298   // This is correct, since the position is supposed to be an 'in between point', i.e., s.length(),
 299   // points to the right of the last element.
 300   if (length==0) {
 301     return;
 302   }
 303   if (UseCompressedOops) {
 304     size_t src_offset = (size_t) objArrayOopDesc::obj_at_offset<narrowOop>(src_pos);
 305     size_t dst_offset = (size_t) objArrayOopDesc::obj_at_offset<narrowOop>(dst_pos);
 306     assert(arrayOopDesc::obj_offset_to_raw<narrowOop>(s, src_offset, NULL) ==
 307            objArrayOop(s)->obj_at_addr_raw<narrowOop>(src_pos), "sanity");
 308     assert(arrayOopDesc::obj_offset_to_raw<narrowOop>(d, dst_offset, NULL) ==
 309            objArrayOop(d)->obj_at_addr_raw<narrowOop>(dst_pos), "sanity");
 310     do_copy(s, src_offset, d, dst_offset, length, CHECK);
 311   } else {
 312     size_t src_offset = (size_t) objArrayOopDesc::obj_at_offset<oop>(src_pos);
 313     size_t dst_offset = (size_t) objArrayOopDesc::obj_at_offset<oop>(dst_pos);
 314     assert(arrayOopDesc::obj_offset_to_raw<oop>(s, src_offset, NULL) ==
 315            objArrayOop(s)->obj_at_addr_raw<oop>(src_pos), "sanity");
 316     assert(arrayOopDesc::obj_offset_to_raw<oop>(d, dst_offset, NULL) ==
 317            objArrayOop(d)->obj_at_addr_raw<oop>(dst_pos), "sanity");
 318     do_copy(s, src_offset, d, dst_offset, length, CHECK);
 319   }
 320 }
 321 
 322 
 323 Klass* ObjArrayKlass::array_klass_impl(bool or_null, int n, TRAPS) {
 324 
 325   assert(dimension() <= n, "check order of chain");
 326   int dim = dimension();
 327   if (dim == n) return this;
 328 
 329   // lock-free read needs acquire semantics
 330   if (higher_dimension_acquire() == NULL) {
 331     if (or_null)  return NULL;
 332 
 333     ResourceMark rm;
 334     JavaThread *jt = (JavaThread *)THREAD;
 335     {
 336       // Ensure atomic creation of higher dimensions
 337       MutexLocker mu(MultiArray_lock, THREAD);
 338 
 339       // Check if another thread beat us
 340       if (higher_dimension() == NULL) {
 341 
 342         // Create multi-dim klass object and link them together
 343         Klass* k =
 344           ObjArrayKlass::allocate_objArray_klass(class_loader_data(), dim + 1, this, CHECK_NULL);
 345         ObjArrayKlass* ak = ObjArrayKlass::cast(k);
 346         ak->set_lower_dimension(this);
 347         // use 'release' to pair with lock-free load
 348         release_set_higher_dimension(ak);
 349         assert(ak->is_objArray_klass(), "incorrect initialization of ObjArrayKlass");
 350       }
 351     }
 352   } else {
 353     CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops());
 354   }
 355 
 356   ObjArrayKlass *ak = ObjArrayKlass::cast(higher_dimension());
 357   if (or_null) {
 358     return ak->array_klass_or_null(n);
 359   }
 360   return ak->array_klass(n, THREAD);
 361 }
 362 
 363 Klass* ObjArrayKlass::array_klass_impl(bool or_null, TRAPS) {
 364   return array_klass_impl(or_null, dimension() +  1, THREAD);
 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(SystemDictionary::Cloneable_klass());
 389     secondaries->push(SystemDictionary::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 // JVM support
 411 
 412 jint ObjArrayKlass::compute_modifier_flags(TRAPS) const {
 413   // The modifier for an objectArray is the same as its element
 414   if (element_klass() == NULL) {
 415     assert(Universe::is_bootstrapping(), "partial objArray only at startup");
 416     return JVM_ACC_ABSTRACT | JVM_ACC_FINAL | JVM_ACC_PUBLIC;
 417   }
 418   // Return the flags of the bottom element type.
 419   jint element_flags = bottom_klass()->compute_modifier_flags(CHECK_0);
 420 
 421   return (element_flags & (JVM_ACC_PUBLIC | JVM_ACC_PRIVATE | JVM_ACC_PROTECTED))
 422                         | (JVM_ACC_ABSTRACT | JVM_ACC_FINAL);
 423 }
 424 
 425 ModuleEntry* ObjArrayKlass::module() const {
 426   assert(bottom_klass() != NULL, "ObjArrayKlass returned unexpected NULL bottom_klass");
 427   // The array is defined in the module of its bottom class
 428   return bottom_klass()->module();
 429 }
 430 
 431 PackageEntry* ObjArrayKlass::package() const {
 432   assert(bottom_klass() != NULL, "ObjArrayKlass returned unexpected NULL bottom_klass");
 433   return bottom_klass()->package();
 434 }
 435 
 436 // Printing
 437 
 438 void ObjArrayKlass::print_on(outputStream* st) const {
 439 #ifndef PRODUCT
 440   Klass::print_on(st);
 441   st->print(" - instance klass: ");
 442   element_klass()->print_value_on(st);
 443   st->cr();
 444 #endif //PRODUCT
 445 }
 446 
 447 void ObjArrayKlass::print_value_on(outputStream* st) const {
 448   assert(is_klass(), "must be klass");
 449 
 450   element_klass()->print_value_on(st);
 451   st->print("[]");
 452 }
 453 
 454 #ifndef PRODUCT
 455 
 456 void ObjArrayKlass::oop_print_on(oop obj, outputStream* st) {
 457   ArrayKlass::oop_print_on(obj, st);
 458   assert(obj->is_objArray(), "must be objArray");
 459   objArrayOop oa = objArrayOop(obj);
 460   int print_len = MIN2((intx) oa->length(), MaxElementPrintSize);
 461   for(int index = 0; index < print_len; index++) {
 462     st->print(" - %3d : ", index);
 463     if (oa->obj_at(index) != NULL) {
 464       oa->obj_at(index)->print_value_on(st);
 465       st->cr();
 466     } else {
 467       st->print_cr("NULL");
 468     }
 469   }
 470   int remaining = oa->length() - print_len;
 471   if (remaining > 0) {
 472     st->print_cr(" - <%d more elements, increase MaxElementPrintSize to print>", remaining);
 473   }
 474 }
 475 
 476 #endif //PRODUCT
 477 
 478 void ObjArrayKlass::oop_print_value_on(oop obj, outputStream* st) {
 479   assert(obj->is_objArray(), "must be objArray");
 480   st->print("a ");
 481   element_klass()->print_value_on(st);
 482   int len = objArrayOop(obj)->length();
 483   st->print("[%d] ", len);
 484   if (obj != NULL) {
 485     obj->print_address_on(st);
 486   } else {
 487     st->print_cr("NULL");
 488   }
 489 }
 490 
 491 const char* ObjArrayKlass::internal_name() const {
 492   return external_name();
 493 }
 494 
 495 
 496 // Verification
 497 
 498 void ObjArrayKlass::verify_on(outputStream* st) {
 499   ArrayKlass::verify_on(st);
 500   guarantee(element_klass()->is_klass(), "should be klass");
 501   guarantee(bottom_klass()->is_klass(), "should be klass");
 502   Klass* bk = bottom_klass();
 503   guarantee(bk->is_instance_klass() || bk->is_typeArray_klass(),  "invalid bottom klass");
 504 }
 505 
 506 void ObjArrayKlass::oop_verify_on(oop obj, outputStream* st) {
 507   ArrayKlass::oop_verify_on(obj, st);
 508   guarantee(obj->is_objArray(), "must be objArray");
 509   objArrayOop oa = objArrayOop(obj);
 510   for(int index = 0; index < oa->length(); index++) {
 511     guarantee(oopDesc::is_oop_or_null(oa->obj_at(index)), "should be oop");
 512   }
 513 }