1 /*
   2  * Copyright (c) 1997, 2018, 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       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           MutexUnlocker mc(Compile_lock);   // for vtables
  84           super_klass = element_super->array_klass(CHECK_0);
  85           for( int i = element_supers->length()-1; i >= 0; i-- ) {
  86             Klass* elem_super = element_supers->at(i);
  87             elem_super->array_klass(CHECK_0);
  88           }
  89           // Now retry from the beginning
  90           ek = element_klass->array_klass(n, CHECK_0);
  91         }  // re-lock
  92         return ek;
  93       }
  94     } else {
  95       // The element type is already Object.  Object[] has direct super of Object.
  96       super_klass = SystemDictionary::Object_klass();
  97     }
  98   }
  99 
 100   // Create type name for klass.
 101   Symbol* name = NULL;
 102   if (!element_klass->is_instance_klass() ||
 103       (name = InstanceKlass::cast(element_klass)->array_name()) == NULL) {
 104 
 105     ResourceMark rm(THREAD);
 106     char *name_str = element_klass->name()->as_C_string();
 107     int len = element_klass->name()->utf8_length();
 108     char *new_str = NEW_RESOURCE_ARRAY(char, len + 4);
 109     int idx = 0;
 110     new_str[idx++] = '[';
 111     if (element_klass->is_instance_klass()) { // it could be an array or simple type
 112       new_str[idx++] = 'L';
 113     }
 114     memcpy(&new_str[idx], name_str, len * sizeof(char));
 115     idx += len;
 116     if (element_klass->is_instance_klass()) {
 117       new_str[idx++] = ';';
 118     }
 119     new_str[idx++] = '\0';
 120     name = SymbolTable::new_permanent_symbol(new_str, CHECK_0);
 121     if (element_klass->is_instance_klass()) {
 122       InstanceKlass* ik = InstanceKlass::cast(element_klass);
 123       ik->set_array_name(name);
 124     }
 125   }
 126 
 127   // Initialize instance variables
 128   ObjArrayKlass* oak = ObjArrayKlass::allocate(loader_data, n, element_klass, name, CHECK_0);
 129 
 130   // Add all classes to our internal class loader list here,
 131   // including classes in the bootstrap (NULL) class loader.
 132   // GC walks these as strong roots.
 133   loader_data->add_class(oak);
 134 
 135   ModuleEntry* module = oak->module();
 136   assert(module != NULL, "No module entry for array");
 137 
 138   // Call complete_create_array_klass after all instance variables has been initialized.
 139   ArrayKlass::complete_create_array_klass(oak, super_klass, module, CHECK_0);
 140 
 141   return oak;
 142 }
 143 
 144 ObjArrayKlass::ObjArrayKlass(int n, Klass* element_klass, Symbol* name) : ArrayKlass(name, ID) {
 145   this->set_dimension(n);
 146   this->set_element_klass(element_klass);
 147   // decrement refcount because object arrays are not explicitly freed.  The
 148   // InstanceKlass array_name() keeps the name counted while the klass is
 149   // loaded.
 150   name->decrement_refcount();
 151 
 152   Klass* bk;
 153   if (element_klass->is_objArray_klass()) {
 154     bk = ObjArrayKlass::cast(element_klass)->bottom_klass();
 155   } else {
 156     bk = element_klass;
 157   }
 158   assert(bk != NULL && (bk->is_instance_klass() || bk->is_typeArray_klass()), "invalid bottom klass");
 159   this->set_bottom_klass(bk);
 160   this->set_class_loader_data(bk->class_loader_data());
 161 
 162   this->set_layout_helper(array_layout_helper(T_OBJECT));
 163   assert(this->is_array_klass(), "sanity");
 164   assert(this->is_objArray_klass(), "sanity");
 165 }
 166 
 167 int ObjArrayKlass::oop_size(oop obj) const {
 168   assert(obj->is_objArray(), "must be object array");
 169   return objArrayOop(obj)->object_size();
 170 }
 171 
 172 objArrayOop ObjArrayKlass::allocate(int length, TRAPS) {
 173   if (length >= 0) {
 174     if (length <= arrayOopDesc::max_array_length(T_OBJECT)) {
 175       int size = objArrayOopDesc::object_size(length);
 176       return (objArrayOop)Universe::heap()->array_allocate(this, size, length,
 177                                                            /* do_zero */ true, THREAD);
 178     } else {
 179       report_java_out_of_memory("Requested array size exceeds VM limit");
 180       JvmtiExport::post_array_size_exhausted();
 181       THROW_OOP_0(Universe::out_of_memory_error_array_size());
 182     }
 183   } else {
 184     THROW_MSG_0(vmSymbols::java_lang_NegativeArraySizeException(), err_msg("%d", length));
 185   }
 186 }
 187 
 188 static int multi_alloc_counter = 0;
 189 
 190 oop ObjArrayKlass::multi_allocate(int rank, jint* sizes, TRAPS) {
 191   int length = *sizes;
 192   // Call to lower_dimension uses this pointer, so most be called before a
 193   // possible GC
 194   Klass* ld_klass = lower_dimension();
 195   // If length < 0 allocate will throw an exception.
 196   objArrayOop array = allocate(length, CHECK_NULL);
 197   objArrayHandle h_array (THREAD, array);
 198   if (rank > 1) {
 199     if (length != 0) {
 200       for (int index = 0; index < length; index++) {
 201         ArrayKlass* ak = ArrayKlass::cast(ld_klass);
 202         oop sub_array = ak->multi_allocate(rank-1, &sizes[1], CHECK_NULL);
 203         h_array->obj_at_put(index, sub_array);
 204       }
 205     } else {
 206       // Since this array dimension has zero length, nothing will be
 207       // allocated, however the lower dimension values must be checked
 208       // for illegal values.
 209       for (int i = 0; i < rank - 1; ++i) {
 210         sizes += 1;
 211         if (*sizes < 0) {
 212           THROW_MSG_0(vmSymbols::java_lang_NegativeArraySizeException(), err_msg("%d", *sizes));
 213         }
 214       }
 215     }
 216   }
 217   return h_array();
 218 }
 219 
 220 // Either oop or narrowOop depending on UseCompressedOops.
 221 void ObjArrayKlass::do_copy(arrayOop s, size_t src_offset,
 222                             arrayOop d, size_t dst_offset, int length, TRAPS) {
 223   if (oopDesc::equals(s, d)) {
 224     // since source and destination are equal we do not need conversion checks.
 225     assert(length > 0, "sanity check");
 226     ArrayAccess<>::oop_arraycopy(s, src_offset, d, dst_offset, length);
 227   } else {
 228     // We have to make sure all elements conform to the destination array
 229     Klass* bound = ObjArrayKlass::cast(d->klass())->element_klass();
 230     Klass* stype = ObjArrayKlass::cast(s->klass())->element_klass();
 231     if (stype == bound || stype->is_subtype_of(bound)) {
 232       // elements are guaranteed to be subtypes, so no check necessary
 233       ArrayAccess<ARRAYCOPY_DISJOINT>::oop_arraycopy(s, src_offset, d, dst_offset, length);
 234     } else {
 235       // slow case: need individual subtype checks
 236       // note: don't use obj_at_put below because it includes a redundant store check
 237       if (!ArrayAccess<ARRAYCOPY_DISJOINT | ARRAYCOPY_CHECKCAST>::oop_arraycopy(s, src_offset, d, dst_offset, length)) {
 238         ResourceMark rm(THREAD);
 239         stringStream ss;
 240         if (!bound->is_subtype_of(stype)) {
 241           ss.print("arraycopy: type mismatch: can not copy %s[] into %s[]",
 242                    stype->external_name(), bound->external_name());
 243         } else {
 244           // oop_arraycopy should return the index in the source array that
 245           // contains the problematic oop.
 246           ss.print("arraycopy: element type mismatch: can not cast one of the elements"
 247                    " of %s[] to the type of the destination array, %s",
 248                    stype->external_name(), bound->external_name());
 249         }
 250         THROW_MSG(vmSymbols::java_lang_ArrayStoreException(), ss.as_string());
 251       }
 252     }
 253   }
 254 }
 255 
 256 void ObjArrayKlass::copy_array(arrayOop s, int src_pos, arrayOop d,
 257                                int dst_pos, int length, TRAPS) {
 258   assert(s->is_objArray(), "must be obj array");
 259 
 260   if (!d->is_objArray()) {
 261     ResourceMark rm(THREAD);
 262     stringStream ss;
 263     if (d->is_typeArray()) {
 264       ss.print("arraycopy: type mismatch: can not copy object array[] into %s[]",
 265                type2name_tab[ArrayKlass::cast(d->klass())->element_type()]);
 266     } else {
 267       ss.print("arraycopy: destination type %s is not an array", d->klass()->external_name());
 268     }
 269     THROW_MSG(vmSymbols::java_lang_ArrayStoreException(), ss.as_string());
 270   }
 271 
 272   // Check is all offsets and lengths are non negative
 273   if (src_pos < 0 || dst_pos < 0 || length < 0) {
 274     // Pass specific exception reason.
 275     ResourceMark rm(THREAD);
 276     stringStream ss;
 277     if (src_pos < 0) {
 278       ss.print("arraycopy: source index %d out of bounds for object array[%d]",
 279                src_pos, s->length());
 280     } else if (dst_pos < 0) {
 281       ss.print("arraycopy: destination index %d out of bounds for object array[%d]",
 282                dst_pos, d->length());
 283     } else {
 284       ss.print("arraycopy: length %d is negative", length);
 285     }
 286     THROW_MSG(vmSymbols::java_lang_ArrayIndexOutOfBoundsException(), ss.as_string());
 287   }
 288   // Check if the ranges are valid
 289   if ((((unsigned int) length + (unsigned int) src_pos) > (unsigned int) s->length()) ||
 290       (((unsigned int) length + (unsigned int) dst_pos) > (unsigned int) d->length())) {
 291     // Pass specific exception reason.
 292     ResourceMark rm(THREAD);
 293     stringStream ss;
 294     if (((unsigned int) length + (unsigned int) src_pos) > (unsigned int) s->length()) {
 295       ss.print("arraycopy: last source index %u out of bounds for object array[%d]",
 296                (unsigned int) length + (unsigned int) src_pos, s->length());
 297     } else {
 298       ss.print("arraycopy: last destination index %u out of bounds for object array[%d]",
 299                (unsigned int) length + (unsigned int) dst_pos, d->length());
 300     }
 301     THROW_MSG(vmSymbols::java_lang_ArrayIndexOutOfBoundsException(), ss.as_string());
 302   }
 303 
 304   // Special case. Boundary cases must be checked first
 305   // This allows the following call: copy_array(s, s.length(), d.length(), 0).
 306   // This is correct, since the position is supposed to be an 'in between point', i.e., s.length(),
 307   // points to the right of the last element.
 308   if (length==0) {
 309     return;
 310   }
 311   if (UseCompressedOops) {
 312     size_t src_offset = (size_t) objArrayOopDesc::obj_at_offset<narrowOop>(src_pos);
 313     size_t dst_offset = (size_t) objArrayOopDesc::obj_at_offset<narrowOop>(dst_pos);
 314     assert(arrayOopDesc::obj_offset_to_raw<narrowOop>(s, src_offset, NULL) ==
 315            objArrayOop(s)->obj_at_addr_raw<narrowOop>(src_pos), "sanity");
 316     assert(arrayOopDesc::obj_offset_to_raw<narrowOop>(d, dst_offset, NULL) ==
 317            objArrayOop(d)->obj_at_addr_raw<narrowOop>(dst_pos), "sanity");
 318     do_copy(s, src_offset, d, dst_offset, length, CHECK);
 319   } else {
 320     size_t src_offset = (size_t) objArrayOopDesc::obj_at_offset<oop>(src_pos);
 321     size_t dst_offset = (size_t) objArrayOopDesc::obj_at_offset<oop>(dst_pos);
 322     assert(arrayOopDesc::obj_offset_to_raw<oop>(s, src_offset, NULL) ==
 323            objArrayOop(s)->obj_at_addr_raw<oop>(src_pos), "sanity");
 324     assert(arrayOopDesc::obj_offset_to_raw<oop>(d, dst_offset, NULL) ==
 325            objArrayOop(d)->obj_at_addr_raw<oop>(dst_pos), "sanity");
 326     do_copy(s, src_offset, d, dst_offset, length, CHECK);
 327   }
 328 }
 329 
 330 
 331 Klass* ObjArrayKlass::array_klass_impl(bool or_null, int n, TRAPS) {
 332 
 333   assert(dimension() <= n, "check order of chain");
 334   int dim = dimension();
 335   if (dim == n) return this;
 336 
 337   // lock-free read needs acquire semantics
 338   if (higher_dimension_acquire() == NULL) {
 339     if (or_null)  return NULL;
 340 
 341     ResourceMark rm;
 342     JavaThread *jt = (JavaThread *)THREAD;
 343     {
 344       MutexLocker mc(Compile_lock, THREAD);   // for vtables
 345       // Ensure atomic creation of higher dimensions
 346       MutexLocker mu(MultiArray_lock, THREAD);
 347 
 348       // Check if another thread beat us
 349       if (higher_dimension() == NULL) {
 350 
 351         // Create multi-dim klass object and link them together
 352         Klass* k =
 353           ObjArrayKlass::allocate_objArray_klass(class_loader_data(), dim + 1, this, CHECK_NULL);
 354         ObjArrayKlass* ak = ObjArrayKlass::cast(k);
 355         ak->set_lower_dimension(this);
 356         // use 'release' to pair with lock-free load
 357         release_set_higher_dimension(ak);
 358         assert(ak->is_objArray_klass(), "incorrect initialization of ObjArrayKlass");
 359       }
 360     }
 361   } else {
 362     CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops());
 363   }
 364 
 365   ObjArrayKlass *ak = ObjArrayKlass::cast(higher_dimension());
 366   if (or_null) {
 367     return ak->array_klass_or_null(n);
 368   }
 369   return ak->array_klass(n, THREAD);
 370 }
 371 
 372 Klass* ObjArrayKlass::array_klass_impl(bool or_null, TRAPS) {
 373   return array_klass_impl(or_null, dimension() +  1, THREAD);
 374 }
 375 
 376 bool ObjArrayKlass::can_be_primary_super_slow() const {
 377   if (!bottom_klass()->can_be_primary_super())
 378     // array of interfaces
 379     return false;
 380   else
 381     return Klass::can_be_primary_super_slow();
 382 }
 383 
 384 GrowableArray<Klass*>* ObjArrayKlass::compute_secondary_supers(int num_extra_slots,
 385                                                                Array<Klass*>* transitive_interfaces) {
 386   assert(transitive_interfaces == NULL, "sanity");
 387   // interfaces = { cloneable_klass, serializable_klass, elemSuper[], ... };
 388   Array<Klass*>* elem_supers = element_klass()->secondary_supers();
 389   int num_elem_supers = elem_supers == NULL ? 0 : elem_supers->length();
 390   int num_secondaries = num_extra_slots + 2 + num_elem_supers;
 391   if (num_secondaries == 2) {
 392     // Must share this for correct bootstrapping!
 393     set_secondary_supers(Universe::the_array_interfaces_array());
 394     return NULL;
 395   } else {
 396     GrowableArray<Klass*>* secondaries = new GrowableArray<Klass*>(num_elem_supers+2);
 397     secondaries->push(SystemDictionary::Cloneable_klass());
 398     secondaries->push(SystemDictionary::Serializable_klass());
 399     for (int i = 0; i < num_elem_supers; i++) {
 400       Klass* elem_super = (Klass*) elem_supers->at(i);
 401       Klass* array_super = elem_super->array_klass_or_null();
 402       assert(array_super != NULL, "must already have been created");
 403       secondaries->push(array_super);
 404     }
 405     return secondaries;
 406   }
 407 }
 408 
 409 bool ObjArrayKlass::compute_is_subtype_of(Klass* k) {
 410   if (!k->is_objArray_klass())
 411     return ArrayKlass::compute_is_subtype_of(k);
 412 
 413   ObjArrayKlass* oak = ObjArrayKlass::cast(k);
 414   return element_klass()->is_subtype_of(oak->element_klass());
 415 }
 416 
 417 void ObjArrayKlass::initialize(TRAPS) {
 418   bottom_klass()->initialize(THREAD);  // dispatches to either InstanceKlass or TypeArrayKlass
 419 }
 420 
 421 void ObjArrayKlass::metaspace_pointers_do(MetaspaceClosure* it) {
 422   ArrayKlass::metaspace_pointers_do(it);
 423   it->push(&_element_klass);
 424   it->push(&_bottom_klass);
 425 }
 426 
 427 // JVM support
 428 
 429 jint ObjArrayKlass::compute_modifier_flags(TRAPS) const {
 430   // The modifier for an objectArray is the same as its element
 431   if (element_klass() == NULL) {
 432     assert(Universe::is_bootstrapping(), "partial objArray only at startup");
 433     return JVM_ACC_ABSTRACT | JVM_ACC_FINAL | JVM_ACC_PUBLIC;
 434   }
 435   // Return the flags of the bottom element type.
 436   jint element_flags = bottom_klass()->compute_modifier_flags(CHECK_0);
 437 
 438   return (element_flags & (JVM_ACC_PUBLIC | JVM_ACC_PRIVATE | JVM_ACC_PROTECTED))
 439                         | (JVM_ACC_ABSTRACT | JVM_ACC_FINAL);
 440 }
 441 
 442 ModuleEntry* ObjArrayKlass::module() const {
 443   assert(bottom_klass() != NULL, "ObjArrayKlass returned unexpected NULL bottom_klass");
 444   // The array is defined in the module of its bottom class
 445   return bottom_klass()->module();
 446 }
 447 
 448 PackageEntry* ObjArrayKlass::package() const {
 449   assert(bottom_klass() != NULL, "ObjArrayKlass returned unexpected NULL bottom_klass");
 450   return bottom_klass()->package();
 451 }
 452 
 453 // Printing
 454 
 455 void ObjArrayKlass::print_on(outputStream* st) const {
 456 #ifndef PRODUCT
 457   Klass::print_on(st);
 458   st->print(" - instance klass: ");
 459   element_klass()->print_value_on(st);
 460   st->cr();
 461 #endif //PRODUCT
 462 }
 463 
 464 void ObjArrayKlass::print_value_on(outputStream* st) const {
 465   assert(is_klass(), "must be klass");
 466 
 467   element_klass()->print_value_on(st);
 468   st->print("[]");
 469 }
 470 
 471 #ifndef PRODUCT
 472 
 473 void ObjArrayKlass::oop_print_on(oop obj, outputStream* st) {
 474   ArrayKlass::oop_print_on(obj, st);
 475   assert(obj->is_objArray(), "must be objArray");
 476   objArrayOop oa = objArrayOop(obj);
 477   int print_len = MIN2((intx) oa->length(), MaxElementPrintSize);
 478   for(int index = 0; index < print_len; index++) {
 479     st->print(" - %3d : ", index);
 480     oa->obj_at(index)->print_value_on(st);
 481     st->cr();
 482   }
 483   int remaining = oa->length() - print_len;
 484   if (remaining > 0) {
 485     st->print_cr(" - <%d more elements, increase MaxElementPrintSize to print>", remaining);
 486   }
 487 }
 488 
 489 #endif //PRODUCT
 490 
 491 void ObjArrayKlass::oop_print_value_on(oop obj, outputStream* st) {
 492   assert(obj->is_objArray(), "must be objArray");
 493   st->print("a ");
 494   element_klass()->print_value_on(st);
 495   int len = objArrayOop(obj)->length();
 496   st->print("[%d] ", len);
 497   obj->print_address_on(st);
 498 }
 499 
 500 const char* ObjArrayKlass::internal_name() const {
 501   return external_name();
 502 }
 503 
 504 
 505 // Verification
 506 
 507 void ObjArrayKlass::verify_on(outputStream* st) {
 508   ArrayKlass::verify_on(st);
 509   guarantee(element_klass()->is_klass(), "should be klass");
 510   guarantee(bottom_klass()->is_klass(), "should be klass");
 511   Klass* bk = bottom_klass();
 512   guarantee(bk->is_instance_klass() || bk->is_typeArray_klass(),  "invalid bottom klass");
 513 }
 514 
 515 void ObjArrayKlass::oop_verify_on(oop obj, outputStream* st) {
 516   ArrayKlass::oop_verify_on(obj, st);
 517   guarantee(obj->is_objArray(), "must be objArray");
 518   objArrayOop oa = objArrayOop(obj);
 519   for(int index = 0; index < oa->length(); index++) {
 520     guarantee(oopDesc::is_oop_or_null(oa->obj_at(index)), "should be oop");
 521   }
 522 }