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 "gc/shared/specialized_oop_closures.hpp"
  33 #include "memory/iterator.inline.hpp"
  34 #include "memory/metadataFactory.hpp"
  35 #include "memory/metaspaceClosure.hpp"
  36 #include "memory/resourceArea.hpp"
  37 #include "memory/universe.hpp"
  38 #include "oops/arrayKlass.inline.hpp"
  39 #include "oops/instanceKlass.hpp"
  40 #include "oops/klass.inline.hpp"
  41 #include "oops/objArrayKlass.inline.hpp"
  42 #include "oops/objArrayOop.inline.hpp"
  43 #include "oops/oop.inline.hpp"
  44 #include "oops/symbol.hpp"
  45 #include "runtime/handles.inline.hpp"
  46 #include "runtime/mutexLocker.hpp"
  47 #include "utilities/macros.hpp"
  48 
  49 ObjArrayKlass* ObjArrayKlass::allocate(ClassLoaderData* loader_data, int n, Klass* k, Symbol* name, TRAPS) {
  50   assert(ObjArrayKlass::header_size() <= InstanceKlass::header_size(),
  51       "array klasses must be same size as InstanceKlass");
  52 
  53   int size = ArrayKlass::static_size(ObjArrayKlass::header_size());
  54 
  55   return new (loader_data, size, THREAD) ObjArrayKlass(n, k, name);
  56 }
  57 
  58 Klass* ObjArrayKlass::allocate_objArray_klass(ClassLoaderData* loader_data,
  59                                                 int n, Klass* element_klass, TRAPS) {
  60 
  61   // Eagerly allocate the direct array supertype.
  62   Klass* super_klass = NULL;
  63   if (!Universe::is_bootstrapping() || SystemDictionary::Object_klass_loaded()) {
  64     Klass* element_super = element_klass->super();
  65     if (element_super != NULL) {
  66       // The element type has a direct super.  E.g., String[] has direct super of Object[].
  67       super_klass = element_super->array_klass_or_null();
  68       bool supers_exist = super_klass != NULL;
  69       // Also, see if the element has secondary supertypes.
  70       // We need an array type for each.
  71       Array<Klass*>* element_supers = element_klass->secondary_supers();
  72       for( int i = element_supers->length()-1; i >= 0; i-- ) {
  73         Klass* elem_super = element_supers->at(i);
  74         if (elem_super->array_klass_or_null() == NULL) {
  75           supers_exist = false;
  76           break;
  77         }
  78       }
  79       if (!supers_exist) {
  80         // Oops.  Not allocated yet.  Back out, allocate it, and retry.
  81         Klass* ek = NULL;
  82         {
  83           MutexUnlocker mu(MultiArray_lock);
  84           MutexUnlocker mc(Compile_lock);   // for vtables
  85           super_klass = element_super->array_klass(CHECK_0);
  86           for( int i = element_supers->length()-1; i >= 0; i-- ) {
  87             Klass* elem_super = element_supers->at(i);
  88             elem_super->array_klass(CHECK_0);
  89           }
  90           // Now retry from the beginning
  91           ek = element_klass->array_klass(n, CHECK_0);
  92         }  // re-lock
  93         return ek;
  94       }
  95     } else {
  96       // The element type is already Object.  Object[] has direct super of Object.
  97       super_klass = SystemDictionary::Object_klass();
  98     }
  99   }
 100 
 101   // Create type name for klass.
 102   Symbol* name = NULL;
 103   if (!element_klass->is_instance_klass() ||
 104       (name = InstanceKlass::cast(element_klass)->array_name()) == NULL) {
 105 
 106     ResourceMark rm(THREAD);
 107     char *name_str = element_klass->name()->as_C_string();
 108     int len = element_klass->name()->utf8_length();
 109     char *new_str = NEW_RESOURCE_ARRAY(char, len + 4);
 110     int idx = 0;
 111     new_str[idx++] = '[';
 112     if (element_klass->is_instance_klass()) { // it could be an array or simple type
 113       new_str[idx++] = 'L';
 114     }
 115     memcpy(&new_str[idx], name_str, len * sizeof(char));
 116     idx += len;
 117     if (element_klass->is_instance_klass()) {
 118       new_str[idx++] = ';';
 119     }
 120     new_str[idx++] = '\0';
 121     name = SymbolTable::new_permanent_symbol(new_str, CHECK_0);
 122     if (element_klass->is_instance_klass()) {
 123       InstanceKlass* ik = InstanceKlass::cast(element_klass);
 124       ik->set_array_name(name);
 125     }
 126   }
 127 
 128   // Initialize instance variables
 129   ObjArrayKlass* oak = ObjArrayKlass::allocate(loader_data, n, element_klass, name, CHECK_0);
 130 
 131   // Add all classes to our internal class loader list here,
 132   // including classes in the bootstrap (NULL) class loader.
 133   // GC walks these as strong roots.
 134   loader_data->add_class(oak);
 135 
 136   ModuleEntry* module = oak->module();
 137   assert(module != NULL, "No module entry for array");
 138 
 139   // Call complete_create_array_klass after all instance variables has been initialized.
 140   ArrayKlass::complete_create_array_klass(oak, super_klass, module, CHECK_0);
 141 
 142   return oak;
 143 }
 144 
 145 ObjArrayKlass::ObjArrayKlass(int n, Klass* element_klass, Symbol* name) : ArrayKlass(name) {
 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   if (length >= 0) {
 175     if (length <= arrayOopDesc::max_array_length(T_OBJECT)) {
 176       int size = objArrayOopDesc::object_size(length);
 177       return (objArrayOop)CollectedHeap::array_allocate(this, size, length, 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_0(vmSymbols::java_lang_NegativeArraySizeException());
 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_0(vmSymbols::java_lang_NegativeArraySizeException());
 213         }
 214       }
 215     }
 216   }
 217   return h_array();
 218 }
 219 
 220 // Either oop or narrowOop depending on UseCompressedOops.
 221 template <class T> void ObjArrayKlass::do_copy(arrayOop s, T* src,
 222                                arrayOop d, T* dst, 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     HeapAccess<>::oop_arraycopy(s, d, src, dst, 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       HeapAccess<ARRAYCOPY_DISJOINT>::oop_arraycopy(s, d, src, dst, 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 (!HeapAccess<ARRAYCOPY_DISJOINT | ARRAYCOPY_CHECKCAST>::oop_arraycopy(s, d, src, dst, length)) {
 238         THROW(vmSymbols::java_lang_ArrayStoreException());
 239       }
 240     }
 241   }
 242 }
 243 
 244 void ObjArrayKlass::copy_array(arrayOop s, int src_pos, arrayOop d,
 245                                int dst_pos, int length, TRAPS) {
 246   assert(s->is_objArray(), "must be obj array");
 247 
 248   if (!d->is_objArray()) {
 249     THROW(vmSymbols::java_lang_ArrayStoreException());
 250   }
 251 
 252   // Check is all offsets and lengths are non negative
 253   if (src_pos < 0 || dst_pos < 0 || length < 0) {
 254     THROW(vmSymbols::java_lang_ArrayIndexOutOfBoundsException());
 255   }
 256   // Check if the ranges are valid
 257   if  ( (((unsigned int) length + (unsigned int) src_pos) > (unsigned int) s->length())
 258      || (((unsigned int) length + (unsigned int) dst_pos) > (unsigned int) d->length()) ) {
 259     THROW(vmSymbols::java_lang_ArrayIndexOutOfBoundsException());
 260   }
 261 
 262   // Special case. Boundary cases must be checked first
 263   // This allows the following call: copy_array(s, s.length(), d.length(), 0).
 264   // This is correct, since the position is supposed to be an 'in between point', i.e., s.length(),
 265   // points to the right of the last element.
 266   if (length==0) {
 267     return;
 268   }
 269   if (UseCompressedOops) {
 270     narrowOop* const src = objArrayOop(s)->obj_at_addr<narrowOop>(src_pos);
 271     narrowOop* const dst = objArrayOop(d)->obj_at_addr<narrowOop>(dst_pos);
 272     do_copy<narrowOop>(s, src, d, dst, length, CHECK);
 273   } else {
 274     oop* const src = objArrayOop(s)->obj_at_addr<oop>(src_pos);
 275     oop* const dst = objArrayOop(d)->obj_at_addr<oop>(dst_pos);
 276     do_copy<oop> (s, src, d, dst, length, CHECK);
 277   }
 278 }
 279 
 280 
 281 Klass* ObjArrayKlass::array_klass_impl(bool or_null, int n, TRAPS) {
 282 
 283   assert(dimension() <= n, "check order of chain");
 284   int dim = dimension();
 285   if (dim == n) return this;
 286 
 287   // lock-free read needs acquire semantics
 288   if (higher_dimension_acquire() == NULL) {
 289     if (or_null)  return NULL;
 290 
 291     ResourceMark rm;
 292     JavaThread *jt = (JavaThread *)THREAD;
 293     {
 294       MutexLocker mc(Compile_lock, THREAD);   // for vtables
 295       // Ensure atomic creation of higher dimensions
 296       MutexLocker mu(MultiArray_lock, THREAD);
 297 
 298       // Check if another thread beat us
 299       if (higher_dimension() == NULL) {
 300 
 301         // Create multi-dim klass object and link them together
 302         Klass* k =
 303           ObjArrayKlass::allocate_objArray_klass(class_loader_data(), dim + 1, this, CHECK_NULL);
 304         ObjArrayKlass* ak = ObjArrayKlass::cast(k);
 305         ak->set_lower_dimension(this);
 306         // use 'release' to pair with lock-free load
 307         release_set_higher_dimension(ak);
 308         assert(ak->is_objArray_klass(), "incorrect initialization of ObjArrayKlass");
 309       }
 310     }
 311   } else {
 312     CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops());
 313   }
 314 
 315   ObjArrayKlass *ak = ObjArrayKlass::cast(higher_dimension());
 316   if (or_null) {
 317     return ak->array_klass_or_null(n);
 318   }
 319   return ak->array_klass(n, THREAD);
 320 }
 321 
 322 Klass* ObjArrayKlass::array_klass_impl(bool or_null, TRAPS) {
 323   return array_klass_impl(or_null, dimension() +  1, THREAD);
 324 }
 325 
 326 bool ObjArrayKlass::can_be_primary_super_slow() const {
 327   if (!bottom_klass()->can_be_primary_super())
 328     // array of interfaces
 329     return false;
 330   else
 331     return Klass::can_be_primary_super_slow();
 332 }
 333 
 334 GrowableArray<Klass*>* ObjArrayKlass::compute_secondary_supers(int num_extra_slots) {
 335   // interfaces = { cloneable_klass, serializable_klass, elemSuper[], ... };
 336   Array<Klass*>* elem_supers = element_klass()->secondary_supers();
 337   int num_elem_supers = elem_supers == NULL ? 0 : elem_supers->length();
 338   int num_secondaries = num_extra_slots + 2 + num_elem_supers;
 339   if (num_secondaries == 2) {
 340     // Must share this for correct bootstrapping!
 341     set_secondary_supers(Universe::the_array_interfaces_array());
 342     return NULL;
 343   } else {
 344     GrowableArray<Klass*>* secondaries = new GrowableArray<Klass*>(num_elem_supers+2);
 345     secondaries->push(SystemDictionary::Cloneable_klass());
 346     secondaries->push(SystemDictionary::Serializable_klass());
 347     for (int i = 0; i < num_elem_supers; i++) {
 348       Klass* elem_super = (Klass*) elem_supers->at(i);
 349       Klass* array_super = elem_super->array_klass_or_null();
 350       assert(array_super != NULL, "must already have been created");
 351       secondaries->push(array_super);
 352     }
 353     return secondaries;
 354   }
 355 }
 356 
 357 bool ObjArrayKlass::compute_is_subtype_of(Klass* k) {
 358   if (!k->is_objArray_klass())
 359     return ArrayKlass::compute_is_subtype_of(k);
 360 
 361   ObjArrayKlass* oak = ObjArrayKlass::cast(k);
 362   return element_klass()->is_subtype_of(oak->element_klass());
 363 }
 364 
 365 void ObjArrayKlass::initialize(TRAPS) {
 366   bottom_klass()->initialize(THREAD);  // dispatches to either InstanceKlass or TypeArrayKlass
 367 }
 368 
 369 void ObjArrayKlass::metaspace_pointers_do(MetaspaceClosure* it) {
 370   ArrayKlass::metaspace_pointers_do(it);
 371   it->push(&_element_klass);
 372   it->push(&_bottom_klass);
 373 }
 374 
 375 // JVM support
 376 
 377 jint ObjArrayKlass::compute_modifier_flags(TRAPS) const {
 378   // The modifier for an objectArray is the same as its element
 379   if (element_klass() == NULL) {
 380     assert(Universe::is_bootstrapping(), "partial objArray only at startup");
 381     return JVM_ACC_ABSTRACT | JVM_ACC_FINAL | JVM_ACC_PUBLIC;
 382   }
 383   // Return the flags of the bottom element type.
 384   jint element_flags = bottom_klass()->compute_modifier_flags(CHECK_0);
 385 
 386   return (element_flags & (JVM_ACC_PUBLIC | JVM_ACC_PRIVATE | JVM_ACC_PROTECTED))
 387                         | (JVM_ACC_ABSTRACT | JVM_ACC_FINAL);
 388 }
 389 
 390 ModuleEntry* ObjArrayKlass::module() const {
 391   assert(bottom_klass() != NULL, "ObjArrayKlass returned unexpected NULL bottom_klass");
 392   // The array is defined in the module of its bottom class
 393   return bottom_klass()->module();
 394 }
 395 
 396 PackageEntry* ObjArrayKlass::package() const {
 397   assert(bottom_klass() != NULL, "ObjArrayKlass returned unexpected NULL bottom_klass");
 398   return bottom_klass()->package();
 399 }
 400 
 401 // Printing
 402 
 403 void ObjArrayKlass::print_on(outputStream* st) const {
 404 #ifndef PRODUCT
 405   Klass::print_on(st);
 406   st->print(" - instance klass: ");
 407   element_klass()->print_value_on(st);
 408   st->cr();
 409 #endif //PRODUCT
 410 }
 411 
 412 void ObjArrayKlass::print_value_on(outputStream* st) const {
 413   assert(is_klass(), "must be klass");
 414 
 415   element_klass()->print_value_on(st);
 416   st->print("[]");
 417 }
 418 
 419 #ifndef PRODUCT
 420 
 421 void ObjArrayKlass::oop_print_on(oop obj, outputStream* st) {
 422   ArrayKlass::oop_print_on(obj, st);
 423   assert(obj->is_objArray(), "must be objArray");
 424   objArrayOop oa = objArrayOop(obj);
 425   int print_len = MIN2((intx) oa->length(), MaxElementPrintSize);
 426   for(int index = 0; index < print_len; index++) {
 427     st->print(" - %3d : ", index);
 428     oa->obj_at(index)->print_value_on(st);
 429     st->cr();
 430   }
 431   int remaining = oa->length() - print_len;
 432   if (remaining > 0) {
 433     st->print_cr(" - <%d more elements, increase MaxElementPrintSize to print>", remaining);
 434   }
 435 }
 436 
 437 #endif //PRODUCT
 438 
 439 void ObjArrayKlass::oop_print_value_on(oop obj, outputStream* st) {
 440   assert(obj->is_objArray(), "must be objArray");
 441   st->print("a ");
 442   element_klass()->print_value_on(st);
 443   int len = objArrayOop(obj)->length();
 444   st->print("[%d] ", len);
 445   obj->print_address_on(st);
 446 }
 447 
 448 const char* ObjArrayKlass::internal_name() const {
 449   return external_name();
 450 }
 451 
 452 
 453 // Verification
 454 
 455 void ObjArrayKlass::verify_on(outputStream* st) {
 456   ArrayKlass::verify_on(st);
 457   guarantee(element_klass()->is_klass(), "should be klass");
 458   guarantee(bottom_klass()->is_klass(), "should be klass");
 459   Klass* bk = bottom_klass();
 460   guarantee(bk->is_instance_klass() || bk->is_typeArray_klass(),  "invalid bottom klass");
 461 }
 462 
 463 void ObjArrayKlass::oop_verify_on(oop obj, outputStream* st) {
 464   ArrayKlass::oop_verify_on(obj, st);
 465   guarantee(obj->is_objArray(), "must be objArray");
 466   objArrayOop oa = objArrayOop(obj);
 467   for(int index = 0; index < oa->length(); index++) {
 468     guarantee(oopDesc::is_oop_or_null(oa->obj_at(index)), "should be oop");
 469   }
 470 }