1 /*
   2  * Copyright (c) 1997, 2016, 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 "gc/shared/gcLocker.hpp"
  31 #include "jvmtifiles/jvmti.h"
  32 #include "memory/resourceArea.hpp"
  33 #include "memory/universe.inline.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 
  40 int ArrayKlass::static_size(int header_size) {
  41   // size of an array klass object
  42   assert(header_size <= InstanceKlass::header_size(), "bad header size");
  43   // If this assert fails, see comments in base_create_array_klass.
  44   header_size = InstanceKlass::header_size();
  45   int vtable_len = Universe::base_vtable_size();
  46   int size = header_size + vtable_len;
  47   return align_metadata_size(size);
  48 }
  49 
  50 
  51 Klass* ArrayKlass::java_super() const {
  52   if (super() == NULL)  return NULL;  // bootstrap case
  53   // Array klasses have primary supertypes which are not reported to Java.
  54   // Example super chain:  String[][] -> Object[][] -> Object[] -> Object
  55   return SystemDictionary::Object_klass();
  56 }
  57 
  58 
  59 oop ArrayKlass::multi_allocate(int rank, jint* sizes, TRAPS) {
  60   ShouldNotReachHere();
  61   return NULL;
  62 }
  63 
  64 // find field according to JVM spec 5.4.3.2, returns the klass in which the field is defined
  65 Klass* ArrayKlass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
  66   // There are no fields in an array klass but look to the super class (Object)
  67   assert(super(), "super klass must be present");
  68   return super()->find_field(name, sig, fd);
  69 }
  70 
  71 Method* ArrayKlass::uncached_lookup_method(const Symbol* name,
  72                                            const Symbol* signature,
  73                                            OverpassLookupMode overpass_mode) const {
  74   // There are no methods in an array klass but the super class (Object) has some
  75   assert(super(), "super klass must be present");
  76   // Always ignore overpass methods in superclasses, although technically the
  77   // super klass of an array, (j.l.Object) should not have
  78   // any overpass methods present.
  79   return super()->uncached_lookup_method(name, signature, Klass::skip_overpass);
  80 }
  81 
  82 ArrayKlass::ArrayKlass(Symbol* name) :
  83   _dimension(1),
  84   _higher_dimension(NULL),
  85   _lower_dimension(NULL) {
  86     // Arrays don't add any new methods, so their vtable is the same size as
  87     // the vtable of klass Object.
  88     set_vtable_length(Universe::base_vtable_size());
  89     set_name(name);
  90     set_super(Universe::is_bootstrapping() ? (Klass*)NULL : SystemDictionary::Object_klass());
  91     set_layout_helper(Klass::_lh_neutral_value);
  92     set_is_cloneable(); // All arrays are considered to be cloneable (See JLS 20.1.5)
  93     TRACE_INIT_KLASS_ID(this);
  94 }
  95 
  96 
  97 // Initialization of vtables and mirror object is done separatly from base_create_array_klass,
  98 // since a GC can happen. At this point all instance variables of the ArrayKlass must be setup.
  99 void ArrayKlass::complete_create_array_klass(ArrayKlass* k, KlassHandle super_klass, ModuleEntry* module_entry, TRAPS) {
 100   ResourceMark rm(THREAD);
 101   k->initialize_supers(super_klass(), CHECK);
 102   k->vtable()->initialize_vtable(false, CHECK);
 103 
 104   // During bootstrapping, before java.base is defined, the module_entry may not be present yet.
 105   // These classes will be put on a fixup list and their module fields will be patched once
 106   // java.base is defined.
 107   assert((module_entry != NULL) || ((module_entry == NULL) && !ModuleEntryTable::javabase_defined()),
 108          "module entry not available post " JAVA_BASE_NAME " definition");
 109   oop module = (module_entry != NULL) ? JNIHandles::resolve(module_entry->module()) : (oop)NULL;
 110   java_lang_Class::create_mirror(k, Handle(THREAD, k->class_loader()), Handle(THREAD, module), Handle(NULL), CHECK);
 111 }
 112 
 113 GrowableArray<Klass*>* ArrayKlass::compute_secondary_supers(int num_extra_slots) {
 114   // interfaces = { cloneable_klass, serializable_klass };
 115   assert(num_extra_slots == 0, "sanity of primitive array type");
 116   // Must share this for correct bootstrapping!
 117   set_secondary_supers(Universe::the_array_interfaces_array());
 118   return NULL;
 119 }
 120 
 121 bool ArrayKlass::compute_is_subtype_of(Klass* k) {
 122   // An array is a subtype of Serializable, Clonable, and Object
 123   return    k == SystemDictionary::Object_klass()
 124          || k == SystemDictionary::Cloneable_klass()
 125          || k == SystemDictionary::Serializable_klass();
 126 }
 127 
 128 objArrayOop ArrayKlass::allocate_arrayArray(int n, int length, TRAPS) {
 129   if (length < 0) {
 130     THROW_0(vmSymbols::java_lang_NegativeArraySizeException());
 131   }
 132   if (length > arrayOopDesc::max_array_length(T_ARRAY)) {
 133     report_java_out_of_memory("Requested array size exceeds VM limit");
 134     JvmtiExport::post_array_size_exhausted();
 135     THROW_OOP_0(Universe::out_of_memory_error_array_size());
 136   }
 137   int size = objArrayOopDesc::object_size(length);
 138   Klass* k = array_klass(n+dimension(), CHECK_0);
 139   ArrayKlass* ak = ArrayKlass::cast(k);
 140   objArrayOop o =
 141     (objArrayOop)CollectedHeap::array_allocate(ak, size, length, CHECK_0);
 142   // initialization to NULL not necessary, area already cleared
 143   return o;
 144 }
 145 
 146 void ArrayKlass::array_klasses_do(void f(Klass* k, TRAPS), TRAPS) {
 147   Klass* k = this;
 148   // Iterate over this array klass and all higher dimensions
 149   while (k != NULL) {
 150     f(k, CHECK);
 151     k = ArrayKlass::cast(k)->higher_dimension();
 152   }
 153 }
 154 
 155 void ArrayKlass::array_klasses_do(void f(Klass* k)) {
 156   Klass* k = this;
 157   // Iterate over this array klass and all higher dimensions
 158   while (k != NULL) {
 159     f(k);
 160     k = ArrayKlass::cast(k)->higher_dimension();
 161   }
 162 }
 163 
 164 // JVM support
 165 
 166 jint ArrayKlass::compute_modifier_flags(TRAPS) const {
 167   return JVM_ACC_ABSTRACT | JVM_ACC_FINAL | JVM_ACC_PUBLIC;
 168 }
 169 
 170 // JVMTI support
 171 
 172 jint ArrayKlass::jvmti_class_status() const {
 173   return JVMTI_CLASS_STATUS_ARRAY;
 174 }
 175 
 176 void ArrayKlass::remove_unshareable_info() {
 177   Klass::remove_unshareable_info();
 178 }
 179 
 180 void ArrayKlass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) {
 181   assert(loader_data == ClassLoaderData::the_null_class_loader_data(), "array classes belong to null loader");
 182   Klass::restore_unshareable_info(loader_data, protection_domain, CHECK);
 183   // Klass recreates the component mirror also
 184 }
 185 
 186 // Printing
 187 
 188 void ArrayKlass::print_on(outputStream* st) const {
 189   assert(is_klass(), "must be klass");
 190   Klass::print_on(st);
 191 }
 192 
 193 void ArrayKlass::print_value_on(outputStream* st) const {
 194   assert(is_klass(), "must be klass");
 195   for(int index = 0; index < dimension(); index++) {
 196     st->print("[]");
 197   }
 198 }
 199 
 200 void ArrayKlass::oop_print_on(oop obj, outputStream* st) {
 201   assert(obj->is_array(), "must be array");
 202   Klass::oop_print_on(obj, st);
 203   st->print_cr(" - length: %d", arrayOop(obj)->length());
 204 }
 205 
 206 
 207 // Verification
 208 
 209 void ArrayKlass::verify_on(outputStream* st) {
 210   Klass::verify_on(st);
 211 }
 212 
 213 void ArrayKlass::oop_verify_on(oop obj, outputStream* st) {
 214   guarantee(obj->is_array(), "must be array");
 215   arrayOop a = arrayOop(obj);
 216   guarantee(a->length() >= 0, "array with negative length?");
 217 }