1 /*
   2  * Copyright (c) 1997, 2019, 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/symbolTable.hpp"
  28 #include "classfile/systemDictionary.hpp"
  29 #include "classfile/vmSymbols.hpp"
  30 #include "gc/shared/collectedHeap.inline.hpp"
  31 #include "jvmtifiles/jvmti.h"
  32 #include "memory/metaspaceClosure.hpp"
  33 #include "memory/resourceArea.hpp"
  34 #include "memory/universe.hpp"
  35 #include "oops/arrayKlass.hpp"
  36 #include "oops/objArrayKlass.hpp"
  37 #include "oops/arrayOop.hpp"
  38 #include "oops/instanceKlass.hpp"
  39 #include "oops/objArrayOop.hpp"
  40 #include "oops/oop.inline.hpp"
  41 #include "runtime/handles.inline.hpp"
  42 
  43 int ArrayKlass::static_size(int header_size) {
  44   // size of an array klass object
  45   assert(header_size <= InstanceKlass::header_size(), "bad header size");
  46   // If this assert fails, see comments in base_create_array_klass.
  47   header_size = InstanceKlass::header_size();
  48   int vtable_len = Universe::base_vtable_size();
  49   int size = header_size + vtable_len;
  50   return align_metadata_size(size);
  51 }
  52 
  53 
  54 InstanceKlass* 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 // find field according to JVM spec 5.4.3.2, returns the klass in which the field is defined
  68 Klass* ArrayKlass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
  69   // There are no fields in an array klass but look to the super class (Object)
  70   assert(super(), "super klass must be present");
  71   return super()->find_field(name, sig, fd);
  72 }
  73 
  74 Method* ArrayKlass::uncached_lookup_method(const Symbol* name,
  75                                            const Symbol* signature,
  76                                            OverpassLookupMode overpass_mode,
  77                                            PrivateLookupMode private_mode) const {
  78   // There are no methods in an array klass but the super class (Object) has some
  79   assert(super(), "super klass must be present");
  80   // Always ignore overpass methods in superclasses, although technically the
  81   // super klass of an array, (j.l.Object) should not have
  82   // any overpass methods present.
  83   return super()->uncached_lookup_method(name, signature, Klass::skip_overpass, private_mode);
  84 }
  85 
  86 ArrayKlass::ArrayKlass(Symbol* name, KlassID id) :
  87   Klass(id),
  88   _dimension(1),
  89   _higher_dimension(NULL),
  90   _lower_dimension(NULL) {
  91     // Arrays don't add any new methods, so their vtable is the same size as
  92     // the vtable of klass Object.
  93     set_vtable_length(Universe::base_vtable_size());
  94     set_name(name);
  95     set_super(Universe::is_bootstrapping() ? NULL : SystemDictionary::Object_klass());
  96     set_layout_helper(Klass::_lh_neutral_value);
  97     set_is_cloneable(); // All arrays are considered to be cloneable (See JLS 20.1.5)
  98     JFR_ONLY(INIT_ID(this);)
  99 }
 100 
 101 Symbol* ArrayKlass::create_element_klass_array_name(bool is_qtype, Klass* element_klass, TRAPS) {
 102   Symbol* name = NULL;
 103   if (!element_klass->is_instance_klass() || is_qtype ||
 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       if (is_qtype) {
 114         new_str[idx++] = 'Q';
 115       } else {
 116         new_str[idx++] = 'L';
 117       }
 118     }
 119     memcpy(&new_str[idx], name_str, len * sizeof(char));
 120     idx += len;
 121     if (element_klass->is_instance_klass()) {
 122       new_str[idx++] = ';';
 123     }
 124     new_str[idx++] = '\0';
 125     name = SymbolTable::new_permanent_symbol(new_str, CHECK_NULL);
 126     if (element_klass->is_instance_klass() && (!is_qtype)) {
 127       InstanceKlass* ik = InstanceKlass::cast(element_klass);
 128       ik->set_array_name(name); // CMH: only cache and deref array_name for L-type...missing for Q-type
 129     }
 130   }
 131 
 132   return name;
 133 }
 134 
 135 // Initialization of vtables and mirror object is done separatly from base_create_array_klass,
 136 // since a GC can happen. At this point all instance variables of the ArrayKlass must be setup.
 137 void ArrayKlass::complete_create_array_klass(ArrayKlass* k, Klass* super_klass, ModuleEntry* module_entry, TRAPS) {
 138   k->initialize_supers(super_klass, NULL, CHECK);
 139   k->vtable().initialize_vtable(false, CHECK);
 140 
 141   // During bootstrapping, before java.base is defined, the module_entry may not be present yet.
 142   // These classes will be put on a fixup list and their module fields will be patched once
 143   // java.base is defined.
 144   assert((module_entry != NULL) || ((module_entry == NULL) && !ModuleEntryTable::javabase_defined()),
 145          "module entry not available post " JAVA_BASE_NAME " definition");
 146   oop module = (module_entry != NULL) ? module_entry->module() : (oop)NULL;
 147   java_lang_Class::create_mirror(k, Handle(THREAD, k->class_loader()), Handle(THREAD, module), Handle(), CHECK);
 148 }
 149 
 150 GrowableArray<Klass*>* ArrayKlass::compute_secondary_supers(int num_extra_slots,
 151                                                             Array<InstanceKlass*>* transitive_interfaces) {
 152   // interfaces = { cloneable_klass, serializable_klass };
 153   assert(num_extra_slots == 0, "sanity of primitive array type");
 154   assert(transitive_interfaces == NULL, "sanity");
 155   // Must share this for correct bootstrapping!
 156   set_secondary_supers(Universe::the_array_interfaces_array());
 157   return NULL;
 158 }
 159 
 160 objArrayOop ArrayKlass::allocate_arrayArray(int n, int length, TRAPS) {
 161   check_array_allocation_length(length, arrayOopDesc::max_array_length(T_ARRAY), CHECK_0);
 162   int size = objArrayOopDesc::object_size(length);
 163   Klass* k = array_klass(FieldType::get_array_storage_properties(name()), n+dimension(), CHECK_0);
 164   ArrayKlass* ak = ArrayKlass::cast(k);
 165   objArrayOop o = (objArrayOop)Universe::heap()->array_allocate(ak, size, length,
 166                                                                 /* do_zero */ true, CHECK_0);
 167   // initialization to NULL not necessary, area already cleared
 168   return o;
 169 }
 170 
 171 void ArrayKlass::array_klasses_do(void f(Klass* k)) {
 172   Klass* k = this;
 173   // Iterate over this array klass and all higher dimensions
 174   while (k != NULL) {
 175     f(k);
 176     k = ArrayKlass::cast(k)->higher_dimension();
 177   }
 178 }
 179 
 180 // JVM support
 181 
 182 jint ArrayKlass::compute_modifier_flags(TRAPS) const {
 183   return JVM_ACC_ABSTRACT | JVM_ACC_FINAL | JVM_ACC_PUBLIC;
 184 }
 185 
 186 // JVMTI support
 187 
 188 jint ArrayKlass::jvmti_class_status() const {
 189   return JVMTI_CLASS_STATUS_ARRAY;
 190 }
 191 
 192 void ArrayKlass::metaspace_pointers_do(MetaspaceClosure* it) {
 193   Klass::metaspace_pointers_do(it);
 194 
 195   ResourceMark rm;
 196   log_trace(cds)("Iter(ArrayKlass): %p (%s)", this, external_name());
 197 
 198   // need to cast away volatile
 199   it->push((Klass**)&_higher_dimension);
 200   it->push((Klass**)&_lower_dimension);
 201 }
 202 
 203 void ArrayKlass::remove_unshareable_info() {
 204   Klass::remove_unshareable_info();
 205   if (_higher_dimension != NULL) {
 206     ArrayKlass *ak = ArrayKlass::cast(higher_dimension());
 207     ak->remove_unshareable_info();
 208   }
 209 }
 210 
 211 void ArrayKlass::remove_java_mirror() {
 212   Klass::remove_java_mirror();
 213   if (_higher_dimension != NULL) {
 214     ArrayKlass *ak = ArrayKlass::cast(higher_dimension());
 215     ak->remove_java_mirror();
 216   }
 217 }
 218 
 219 void ArrayKlass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) {
 220   assert(loader_data == ClassLoaderData::the_null_class_loader_data(), "array classes belong to null loader");
 221   Klass::restore_unshareable_info(loader_data, protection_domain, CHECK);
 222   // Klass recreates the component mirror also
 223 
 224   if (_higher_dimension != NULL) {
 225     ArrayKlass *ak = ArrayKlass::cast(higher_dimension());
 226     ak->restore_unshareable_info(loader_data, protection_domain, CHECK);
 227   }
 228 }
 229 
 230 // Printing
 231 
 232 void ArrayKlass::print_on(outputStream* st) const {
 233   assert(is_klass(), "must be klass");
 234   Klass::print_on(st);
 235 }
 236 
 237 void ArrayKlass::print_value_on(outputStream* st) const {
 238   assert(is_klass(), "must be klass");
 239   for(int index = 0; index < dimension(); index++) {
 240     st->print("[]");
 241   }
 242 }
 243 
 244 void ArrayKlass::oop_print_on(oop obj, outputStream* st) {
 245   assert(obj->is_array(), "must be array");
 246   Klass::oop_print_on(obj, st);
 247   st->print_cr(" - length: %d", arrayOop(obj)->length());
 248 }
 249 
 250 
 251 // Verification
 252 
 253 void ArrayKlass::verify_on(outputStream* st) {
 254   Klass::verify_on(st);
 255 }
 256 
 257 void ArrayKlass::oop_verify_on(oop obj, outputStream* st) {
 258   guarantee(obj->is_array(), "must be array");
 259   arrayOop a = arrayOop(obj);
 260   guarantee(a->length() >= 0, "array with negative length?");
 261 }