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/javaClasses.hpp"
  27 #include "classfile/systemDictionary.hpp"
  28 #include "classfile/vmSymbols.hpp"
  29 #include "gc/shared/collectedHeap.inline.hpp"
  30 #include "jvmtifiles/jvmti.h"
  31 #include "memory/metaspaceClosure.hpp"
  32 #include "memory/resourceArea.hpp"
  33 #include "memory/universe.hpp"
  34 #include "oops/arrayKlass.hpp"
  35 #include "oops/arrayOop.hpp"
  36 #include "oops/instanceKlass.hpp"
  37 #include "oops/objArrayOop.hpp"
  38 #include "oops/oop.inline.hpp"
  39 #include "runtime/handles.inline.hpp"
  40 
  41 int ArrayKlass::static_size(int header_size) {
  42   // size of an array klass object
  43   assert(header_size <= InstanceKlass::header_size(), "bad header size");
  44   // If this assert fails, see comments in base_create_array_klass.
  45   header_size = InstanceKlass::header_size();
  46   int vtable_len = Universe::base_vtable_size();
  47   int size = header_size + vtable_len;
  48   return align_metadata_size(size);
  49 }
  50 
  51 
  52 Klass* ArrayKlass::java_super() const {
  53   if (super() == NULL)  return NULL;  // bootstrap case
  54   // Array klasses have primary supertypes which are not reported to Java.
  55   // Example super chain:  String[][] -> Object[][] -> Object[] -> Object
  56   return SystemDictionary::Object_klass();
  57 }
  58 
  59 
  60 oop ArrayKlass::multi_allocate(int rank, jint* sizes, TRAPS) {
  61   ShouldNotReachHere();
  62   return NULL;
  63 }
  64 
  65 // find field according to JVM spec 5.4.3.2, returns the klass in which the field is defined
  66 Klass* ArrayKlass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
  67   // There are no fields in an array klass but look to the super class (Object)
  68   assert(super(), "super klass must be present");
  69   return super()->find_field(name, sig, fd);
  70 }
  71 
  72 Method* ArrayKlass::uncached_lookup_method(const Symbol* name,
  73                                            const Symbol* signature,
  74                                            OverpassLookupMode overpass_mode,
  75                                            PrivateLookupMode private_mode) const {
  76   // There are no methods in an array klass but the super class (Object) has some
  77   assert(super(), "super klass must be present");
  78   // Always ignore overpass methods in superclasses, although technically the
  79   // super klass of an array, (j.l.Object) should not have
  80   // any overpass methods present.
  81   return super()->uncached_lookup_method(name, signature, Klass::skip_overpass, private_mode);
  82 }
  83 
  84 ArrayKlass::ArrayKlass(Symbol* name) :
  85   _dimension(1),
  86   _higher_dimension(NULL),
  87   _lower_dimension(NULL) {
  88     // Arrays don't add any new methods, so their vtable is the same size as
  89     // the vtable of klass Object.
  90     set_vtable_length(Universe::base_vtable_size());
  91     set_name(name);
  92     set_super(Universe::is_bootstrapping() ? (Klass*)NULL : SystemDictionary::Object_klass());
  93     set_layout_helper(Klass::_lh_neutral_value);
  94     set_is_cloneable(); // All arrays are considered to be cloneable (See JLS 20.1.5)
  95     TRACE_INIT_ID(this);
  96 }
  97 
  98 
  99 // Initialization of vtables and mirror object is done separatly from base_create_array_klass,
 100 // since a GC can happen. At this point all instance variables of the ArrayKlass must be setup.
 101 void ArrayKlass::complete_create_array_klass(ArrayKlass* k, Klass* super_klass, ModuleEntry* module_entry, TRAPS) {
 102   ResourceMark rm(THREAD);
 103   k->initialize_supers(super_klass, NULL, CHECK);
 104   k->vtable().initialize_vtable(false, CHECK);
 105 
 106   // During bootstrapping, before java.base is defined, the module_entry may not be present yet.
 107   // These classes will be put on a fixup list and their module fields will be patched once
 108   // java.base is defined.
 109   assert((module_entry != NULL) || ((module_entry == NULL) && !ModuleEntryTable::javabase_defined()),
 110          "module entry not available post " JAVA_BASE_NAME " definition");
 111   oop module = (module_entry != NULL) ? module_entry->module() : (oop)NULL;
 112   java_lang_Class::create_mirror(k, Handle(THREAD, k->class_loader()), Handle(THREAD, module), Handle(), CHECK);
 113 }
 114 
 115 GrowableArray<Klass*>* ArrayKlass::compute_secondary_supers(int num_extra_slots,
 116                                                             Array<Klass*>* transitive_interfaces) {
 117   // interfaces = { cloneable_klass, serializable_klass };
 118   assert(num_extra_slots == 0, "sanity of primitive array type");
 119   assert(transitive_interfaces == NULL, "sanity");
 120   // Must share this for correct bootstrapping!
 121   set_secondary_supers(Universe::the_array_interfaces_array());
 122   return NULL;
 123 }
 124 
 125 bool ArrayKlass::compute_is_subtype_of(Klass* k) {
 126   // An array is a subtype of Serializable, Clonable, and Object
 127   return    k == SystemDictionary::Object_klass()
 128          || k == SystemDictionary::Cloneable_klass()
 129          || k == SystemDictionary::Serializable_klass();
 130 }
 131 
 132 objArrayOop ArrayKlass::allocate_arrayArray(int n, int length, TRAPS) {
 133   if (length < 0) {
 134     THROW_0(vmSymbols::java_lang_NegativeArraySizeException());
 135   }
 136   if (length > arrayOopDesc::max_array_length(T_ARRAY)) {
 137     report_java_out_of_memory("Requested array size exceeds VM limit");
 138     JvmtiExport::post_array_size_exhausted();
 139     THROW_OOP_0(Universe::out_of_memory_error_array_size());
 140   }
 141   int size = objArrayOopDesc::object_size(length);
 142   Klass* k = array_klass(n+dimension(), CHECK_0);
 143   ArrayKlass* ak = ArrayKlass::cast(k);
 144   objArrayOop o =
 145     (objArrayOop)CollectedHeap::array_allocate(ak, size, length, CHECK_0);
 146   // initialization to NULL not necessary, area already cleared
 147   return o;
 148 }
 149 
 150 void ArrayKlass::array_klasses_do(void f(Klass* k, TRAPS), TRAPS) {
 151   Klass* k = this;
 152   // Iterate over this array klass and all higher dimensions
 153   while (k != NULL) {
 154     f(k, CHECK);
 155     k = ArrayKlass::cast(k)->higher_dimension();
 156   }
 157 }
 158 
 159 void ArrayKlass::array_klasses_do(void f(Klass* k)) {
 160   Klass* k = this;
 161   // Iterate over this array klass and all higher dimensions
 162   while (k != NULL) {
 163     f(k);
 164     k = ArrayKlass::cast(k)->higher_dimension();
 165   }
 166 }
 167 
 168 // JVM support
 169 
 170 jint ArrayKlass::compute_modifier_flags(TRAPS) const {
 171   return JVM_ACC_ABSTRACT | JVM_ACC_FINAL | JVM_ACC_PUBLIC;
 172 }
 173 
 174 // JVMTI support
 175 
 176 jint ArrayKlass::jvmti_class_status() const {
 177   return JVMTI_CLASS_STATUS_ARRAY;
 178 }
 179 
 180 void ArrayKlass::metaspace_pointers_do(MetaspaceClosure* it) {
 181   Klass::metaspace_pointers_do(it);
 182 
 183   ResourceMark rm;
 184   log_trace(cds)("Iter(ArrayKlass): %p (%s)", this, external_name());
 185 
 186   // need to cast away volatile
 187   it->push((Klass**)&_higher_dimension);
 188   it->push((Klass**)&_lower_dimension);
 189 }
 190 
 191 void ArrayKlass::remove_unshareable_info() {
 192   Klass::remove_unshareable_info();
 193   if (_higher_dimension != NULL) {
 194     ArrayKlass *ak = ArrayKlass::cast(higher_dimension());
 195     ak->remove_unshareable_info();
 196   }
 197 }
 198 
 199 void ArrayKlass::remove_java_mirror() {
 200   Klass::remove_java_mirror();
 201   if (_higher_dimension != NULL) {
 202     ArrayKlass *ak = ArrayKlass::cast(higher_dimension());
 203     ak->remove_java_mirror();
 204   }
 205 }
 206 
 207 void ArrayKlass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) {
 208   assert(loader_data == ClassLoaderData::the_null_class_loader_data(), "array classes belong to null loader");
 209   Klass::restore_unshareable_info(loader_data, protection_domain, CHECK);
 210   // Klass recreates the component mirror also
 211 
 212   if (_higher_dimension != NULL) {
 213     ArrayKlass *ak = ArrayKlass::cast(higher_dimension());
 214     ak->restore_unshareable_info(loader_data, protection_domain, CHECK);
 215   }
 216 }
 217 
 218 // Printing
 219 
 220 void ArrayKlass::print_on(outputStream* st) const {
 221   assert(is_klass(), "must be klass");
 222   Klass::print_on(st);
 223 }
 224 
 225 void ArrayKlass::print_value_on(outputStream* st) const {
 226   assert(is_klass(), "must be klass");
 227   for(int index = 0; index < dimension(); index++) {
 228     st->print("[]");
 229   }
 230 }
 231 
 232 void ArrayKlass::oop_print_on(oop obj, outputStream* st) {
 233   assert(obj->is_array(), "must be array");
 234   Klass::oop_print_on(obj, st);
 235   st->print_cr(" - length: %d", arrayOop(obj)->length());
 236 }
 237 
 238 
 239 // Verification
 240 
 241 void ArrayKlass::verify_on(outputStream* st) {
 242   Klass::verify_on(st);
 243 }
 244 
 245 void ArrayKlass::oop_verify_on(oop obj, outputStream* st) {
 246   guarantee(obj->is_array(), "must be array");
 247   arrayOop a = arrayOop(obj);
 248   guarantee(a->length() >= 0, "array with negative length?");
 249 }