1 /*
   2  * Copyright (c) 1997, 2014, 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_interface/collectedHeap.inline.hpp"
  30 #include "jvmtifiles/jvmti.h"
  31 #include "memory/gcLocker.hpp"
  32 #include "memory/universe.inline.hpp"
  33 #include "oops/arrayKlass.hpp"
  34 #include "oops/arrayOop.hpp"
  35 #include "oops/instanceKlass.hpp"
  36 #include "oops/objArrayOop.hpp"
  37 #include "oops/oop.inline.hpp"
  38 
  39 int ArrayKlass::static_size(int header_size) {
  40   // size of an array klass object
  41   assert(header_size <= InstanceKlass::header_size(), "bad header size");
  42   // If this assert fails, see comments in base_create_array_klass.
  43   header_size = InstanceKlass::header_size();
  44   int vtable_len = Universe::base_vtable_size();
  45 #ifdef _LP64
  46   int size = header_size + align_object_offset(vtable_len);
  47 #else
  48   int size = header_size + vtable_len;
  49 #endif
  50   return align_object_size(size);
  51 }
  52 
  53 
  54 Klass* ArrayKlass::java_super() const {
  55   if (super() == NULL)  return NULL;  // bootstrap case
  56   // Array klasses have primary supertypes which are not reported to Java.
  57   // Example super chain:  String[][] -> Object[][] -> Object[] -> Object
  58   return SystemDictionary::Object_klass();
  59 }
  60 
  61 
  62 oop ArrayKlass::multi_allocate(int rank, jint* sizes, TRAPS) {
  63   ShouldNotReachHere();
  64   return NULL;
  65 }
  66 
  67 Method* ArrayKlass::uncached_lookup_method(Symbol* name, Symbol* signature, MethodLookupMode mode) const {
  68   // There are no methods in an array klass but the super class (Object) has some
  69   assert(super(), "super klass must be present");
  70   return super()->uncached_lookup_method(name, signature, mode);
  71 }
  72 
  73 ArrayKlass::ArrayKlass(Symbol* name, DispatchTag tag) : Klass(tag) {
  74   set_name(name);
  75 
  76   set_super(Universe::is_bootstrapping() ? (Klass*)NULL : SystemDictionary::Object_klass());
  77   set_layout_helper(Klass::_lh_neutral_value);
  78   set_dimension(1);
  79   set_higher_dimension(NULL);
  80   set_lower_dimension(NULL);
  81   set_component_mirror(NULL);
  82   // Arrays don't add any new methods, so their vtable is the same size as
  83   // the vtable of klass Object.
  84   int vtable_size = Universe::base_vtable_size();
  85   set_vtable_length(vtable_size);
  86   set_is_cloneable(); // All arrays are considered to be cloneable (See JLS 20.1.5)
  87 }
  88 
  89 
  90 // Initialization of vtables and mirror object is done separatly from base_create_array_klass,
  91 // since a GC can happen. At this point all instance variables of the ArrayKlass must be setup.
  92 void ArrayKlass::complete_create_array_klass(ArrayKlass* k, KlassHandle super_klass, TRAPS) {
  93   ResourceMark rm(THREAD);
  94   k->initialize_supers(super_klass(), CHECK);
  95   k->vtable()->initialize_vtable(false, CHECK);
  96   java_lang_Class::create_mirror(k, Handle(NULL), Handle(NULL), CHECK);
  97 }
  98 
  99 GrowableArray<Klass*>* ArrayKlass::compute_secondary_supers(int num_extra_slots) {
 100   // interfaces = { cloneable_klass, serializable_klass };
 101   assert(num_extra_slots == 0, "sanity of primitive array type");
 102   // Must share this for correct bootstrapping!
 103   set_secondary_supers(Universe::the_array_interfaces_array());
 104   return NULL;
 105 }
 106 
 107 bool ArrayKlass::compute_is_subtype_of(Klass* k) {
 108   // An array is a subtype of Serializable, Clonable, and Object
 109   return    k == SystemDictionary::Object_klass()
 110          || k == SystemDictionary::Cloneable_klass()
 111          || k == SystemDictionary::Serializable_klass();
 112 }
 113 
 114 
 115 inline intptr_t* ArrayKlass::start_of_vtable() const {
 116   // all vtables start at the same place, that's why we use InstanceKlass::header_size here
 117   return ((intptr_t*)this) + InstanceKlass::header_size();
 118 }
 119 
 120 
 121 klassVtable* ArrayKlass::vtable() const {
 122   KlassHandle kh(Thread::current(), this);
 123   return new klassVtable(kh, start_of_vtable(), vtable_length() / vtableEntry::size());
 124 }
 125 
 126 
 127 objArrayOop ArrayKlass::allocate_arrayArray(int n, int length, TRAPS) {
 128   if (length < 0) {
 129     THROW_0(vmSymbols::java_lang_NegativeArraySizeException());
 130   }
 131   if (length > arrayOopDesc::max_array_length(T_ARRAY)) {
 132     report_java_out_of_memory("Requested array size exceeds VM limit");
 133     JvmtiExport::post_array_size_exhausted();
 134     THROW_OOP_0(Universe::out_of_memory_error_array_size());
 135   }
 136   int size = objArrayOopDesc::object_size(length);
 137   Klass* k = array_klass(n+dimension(), CHECK_0);
 138   ArrayKlass* ak = ArrayKlass::cast(k);
 139   objArrayOop o =
 140     (objArrayOop)CollectedHeap::array_allocate(ak, size, length, CHECK_0);
 141   // initialization to NULL not necessary, area already cleared
 142   return o;
 143 }
 144 
 145 void ArrayKlass::array_klasses_do(void f(Klass* k, TRAPS), TRAPS) {
 146   Klass* k = this;
 147   // Iterate over this array klass and all higher dimensions
 148   while (k != NULL) {
 149     f(k, CHECK);
 150     k = ArrayKlass::cast(k)->higher_dimension();
 151   }
 152 }
 153 
 154 void ArrayKlass::array_klasses_do(void f(Klass* k)) {
 155   Klass* k = this;
 156   // Iterate over this array klass and all higher dimensions
 157   while (k != NULL) {
 158     f(k);
 159     k = ArrayKlass::cast(k)->higher_dimension();
 160   }
 161 }
 162 
 163 // GC support
 164 
 165 void ArrayKlass::oops_do(OopClosure* cl) {
 166   Klass::oops_do(cl);
 167 
 168   cl->do_oop(adr_component_mirror());
 169 }
 170 
 171 // JVM support
 172 
 173 jint ArrayKlass::compute_modifier_flags(TRAPS) const {
 174   return JVM_ACC_ABSTRACT | JVM_ACC_FINAL | JVM_ACC_PUBLIC;
 175 }
 176 
 177 // JVMTI support
 178 
 179 jint ArrayKlass::jvmti_class_status() const {
 180   return JVMTI_CLASS_STATUS_ARRAY;
 181 }
 182 
 183 void ArrayKlass::remove_unshareable_info() {
 184   Klass::remove_unshareable_info();
 185   // Clear the java mirror
 186   set_component_mirror(NULL);
 187 }
 188 
 189 void ArrayKlass::restore_unshareable_info(TRAPS) {
 190   Klass::restore_unshareable_info(CHECK);
 191   // Klass recreates the component mirror also
 192 }
 193 
 194 // Printing
 195 
 196 void ArrayKlass::print_on(outputStream* st) const {
 197   assert(is_klass(), "must be klass");
 198   Klass::print_on(st);
 199 }
 200 
 201 void ArrayKlass::print_value_on(outputStream* st) const {
 202   assert(is_klass(), "must be klass");
 203   for(int index = 0; index < dimension(); index++) {
 204     st->print("[]");
 205   }
 206 }
 207 
 208 void ArrayKlass::oop_print_on(oop obj, outputStream* st) {
 209   assert(obj->is_array(), "must be array");
 210   Klass::oop_print_on(obj, st);
 211   st->print_cr(" - length: %d", arrayOop(obj)->length());
 212 }
 213 
 214 
 215 // Verification
 216 
 217 void ArrayKlass::verify_on(outputStream* st) {
 218   Klass::verify_on(st);
 219 
 220   if (component_mirror() != NULL) {
 221     guarantee(component_mirror()->klass() != NULL, "should have a class");
 222   }
 223 }
 224 
 225 void ArrayKlass::oop_verify_on(oop obj, outputStream* st) {
 226   guarantee(obj->is_array(), "must be array");
 227   arrayOop a = arrayOop(obj);
 228   guarantee(a->length() >= 0, "array with negative length?");
 229 }