1 /* 2 * Copyright (c) 1997, 2017, 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 // 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(Symbol* name, Symbol* signature, OverpassLookupMode overpass_mode) const { 75 // There are no methods in an array klass but the super class (Object) has some 76 assert(super(), "super klass must be present"); 77 // Always ignore overpass methods in superclasses, although technically the 78 // super klass of an array, (j.l.Object) should not have 79 // any overpass methods present. 80 return super()->uncached_lookup_method(name, signature, Klass::skip_overpass); 81 } 82 83 ArrayKlass::ArrayKlass(Symbol* name) { 84 set_name(name); 85 86 set_super(Universe::is_bootstrapping() ? (Klass*)NULL : SystemDictionary::Object_klass()); 87 set_layout_helper(Klass::_lh_neutral_value); 88 set_dimension(1); 89 set_higher_dimension(NULL); 90 set_lower_dimension(NULL); 91 set_component_mirror(NULL); 92 // Arrays don't add any new methods, so their vtable is the same size as 93 // the vtable of klass Object. 94 int vtable_size = Universe::base_vtable_size(); 95 set_vtable_length(vtable_size); 96 set_is_cloneable(); // All arrays are considered to be cloneable (See JLS 20.1.5) 97 } 98 99 100 // Initialization of vtables and mirror object is done separatly from base_create_array_klass, 101 // since a GC can happen. At this point all instance variables of the ArrayKlass must be setup. 102 void ArrayKlass::complete_create_array_klass(ArrayKlass* k, KlassHandle super_klass, TRAPS) { 103 ResourceMark rm(THREAD); 104 k->initialize_supers(super_klass(), CHECK); 105 k->vtable()->initialize_vtable(false, CHECK); 106 java_lang_Class::create_mirror(k, Handle(THREAD, k->class_loader()), Handle(NULL), CHECK); 107 } 108 109 GrowableArray<Klass*>* ArrayKlass::compute_secondary_supers(int num_extra_slots) { 110 // interfaces = { cloneable_klass, serializable_klass }; 111 assert(num_extra_slots == 0, "sanity of primitive array type"); 112 // Must share this for correct bootstrapping! 113 set_secondary_supers(Universe::the_array_interfaces_array()); 114 return NULL; 115 } 116 117 bool ArrayKlass::compute_is_subtype_of(Klass* k) { 118 // An array is a subtype of Serializable, Clonable, and Object 119 return k == SystemDictionary::Object_klass() 120 || k == SystemDictionary::Cloneable_klass() 121 || k == SystemDictionary::Serializable_klass(); 122 } 123 124 125 inline intptr_t* ArrayKlass::start_of_vtable() const { 126 // all vtables start at the same place, that's why we use InstanceKlass::header_size here 127 return ((intptr_t*)this) + InstanceKlass::header_size(); 128 } 129 130 131 klassVtable* ArrayKlass::vtable() const { 132 KlassHandle kh(Thread::current(), this); 133 return new klassVtable(kh, start_of_vtable(), vtable_length() / vtableEntry::size()); 134 } 135 136 137 objArrayOop ArrayKlass::allocate_arrayArray(int n, int length, TRAPS) { 138 if (length < 0) { 139 THROW_0(vmSymbols::java_lang_NegativeArraySizeException()); 140 } 141 if (length > arrayOopDesc::max_array_length(T_ARRAY)) { 142 report_java_out_of_memory("Requested array size exceeds VM limit"); 143 JvmtiExport::post_array_size_exhausted(); 144 THROW_OOP_0(Universe::out_of_memory_error_array_size()); 145 } 146 int size = objArrayOopDesc::object_size(length); 147 Klass* k = array_klass(n+dimension(), CHECK_0); 148 ArrayKlass* ak = ArrayKlass::cast(k); 149 objArrayOop o = 150 (objArrayOop)CollectedHeap::array_allocate(ak, size, length, CHECK_0); 151 // initialization to NULL not necessary, area already cleared 152 return o; 153 } 154 155 void ArrayKlass::array_klasses_do(void f(Klass* k, TRAPS), TRAPS) { 156 Klass* k = this; 157 // Iterate over this array klass and all higher dimensions 158 while (k != NULL) { 159 f(k, CHECK); 160 k = ArrayKlass::cast(k)->higher_dimension(); 161 } 162 } 163 164 void ArrayKlass::array_klasses_do(void f(Klass* k)) { 165 Klass* k = this; 166 // Iterate over this array klass and all higher dimensions 167 while (k != NULL) { 168 f(k); 169 k = ArrayKlass::cast(k)->higher_dimension(); 170 } 171 } 172 173 // GC support 174 175 void ArrayKlass::oops_do(OopClosure* cl) { 176 Klass::oops_do(cl); 177 178 cl->do_oop(adr_component_mirror()); 179 } 180 181 // JVM support 182 183 jint ArrayKlass::compute_modifier_flags(TRAPS) const { 184 return JVM_ACC_ABSTRACT | JVM_ACC_FINAL | JVM_ACC_PUBLIC; 185 } 186 187 // JVMTI support 188 189 jint ArrayKlass::jvmti_class_status() const { 190 return JVMTI_CLASS_STATUS_ARRAY; 191 } 192 193 void ArrayKlass::remove_unshareable_info() { 194 Klass::remove_unshareable_info(); 195 // Clear the java mirror 196 set_component_mirror(NULL); 197 } 198 199 void ArrayKlass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) { 200 assert(loader_data == ClassLoaderData::the_null_class_loader_data(), "array classes belong to null loader"); 201 Klass::restore_unshareable_info(loader_data, protection_domain, CHECK); 202 // Klass recreates the component mirror also 203 } 204 205 // Printing 206 207 void ArrayKlass::print_on(outputStream* st) const { 208 assert(is_klass(), "must be klass"); 209 Klass::print_on(st); 210 } 211 212 void ArrayKlass::print_value_on(outputStream* st) const { 213 assert(is_klass(), "must be klass"); 214 for(int index = 0; index < dimension(); index++) { 215 st->print("[]"); 216 } 217 } 218 219 void ArrayKlass::oop_print_on(oop obj, outputStream* st) { 220 assert(obj->is_array(), "must be array"); 221 Klass::oop_print_on(obj, st); 222 st->print_cr(" - length: %d", arrayOop(obj)->length()); 223 } 224 225 226 // Verification 227 228 void ArrayKlass::verify_on(outputStream* st) { 229 Klass::verify_on(st); 230 231 if (component_mirror() != NULL) { 232 guarantee(component_mirror()->klass() != NULL, "should have a class"); 233 } 234 } 235 236 void ArrayKlass::oop_verify_on(oop obj, outputStream* st) { 237 guarantee(obj->is_array(), "must be array"); 238 arrayOop a = arrayOop(obj); 239 guarantee(a->length() >= 0, "array with negative length?"); 240 }