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 JFR_ONLY(INIT_ID(this);)
98 }
99
100
101 // Initialization of vtables and mirror object is done separatly from base_create_array_klass,
102 // since a GC can happen. At this point all instance variables of the ArrayKlass must be setup.
103 void ArrayKlass::complete_create_array_klass(ArrayKlass* k, KlassHandle super_klass, TRAPS) {
104 ResourceMark rm(THREAD);
105 k->initialize_supers(super_klass(), CHECK);
106 k->vtable()->initialize_vtable(false, CHECK);
107 java_lang_Class::create_mirror(k, Handle(THREAD, k->class_loader()), Handle(NULL), CHECK);
108 }
109
110 GrowableArray<Klass*>* ArrayKlass::compute_secondary_supers(int num_extra_slots) {
111 // interfaces = { cloneable_klass, serializable_klass };
112 assert(num_extra_slots == 0, "sanity of primitive array type");
113 // Must share this for correct bootstrapping!
114 set_secondary_supers(Universe::the_array_interfaces_array());
115 return NULL;
116 }
117
118 bool ArrayKlass::compute_is_subtype_of(Klass* k) {
119 // An array is a subtype of Serializable, Clonable, and Object
120 return k == SystemDictionary::Object_klass()
121 || k == SystemDictionary::Cloneable_klass()
122 || k == SystemDictionary::Serializable_klass();
123 }
124
125
126 inline intptr_t* ArrayKlass::start_of_vtable() const {
127 // all vtables start at the same place, that's why we use InstanceKlass::header_size here
128 return ((intptr_t*)this) + InstanceKlass::header_size();
129 }
130
131
132 klassVtable* ArrayKlass::vtable() const {
133 KlassHandle kh(Thread::current(), this);
134 return new klassVtable(kh, start_of_vtable(), vtable_length() / vtableEntry::size());
135 }
136
137
138 objArrayOop ArrayKlass::allocate_arrayArray(int n, int length, TRAPS) {
139 if (length < 0) {
140 THROW_0(vmSymbols::java_lang_NegativeArraySizeException());
141 }
142 if (length > arrayOopDesc::max_array_length(T_ARRAY)) {
143 report_java_out_of_memory("Requested array size exceeds VM limit");
144 JvmtiExport::post_array_size_exhausted();
145 THROW_OOP_0(Universe::out_of_memory_error_array_size());
146 }
147 int size = objArrayOopDesc::object_size(length);
148 Klass* k = array_klass(n+dimension(), CHECK_0);
149 ArrayKlass* ak = ArrayKlass::cast(k);
150 objArrayOop o =
151 (objArrayOop)CollectedHeap::array_allocate(ak, size, length, CHECK_0);
152 // initialization to NULL not necessary, area already cleared
153 return o;
154 }
155
156 void ArrayKlass::array_klasses_do(void f(Klass* k, TRAPS), TRAPS) {
157 Klass* k = this;
158 // Iterate over this array klass and all higher dimensions
159 while (k != NULL) {
160 f(k, CHECK);
161 k = ArrayKlass::cast(k)->higher_dimension();
162 }
163 }
164
165 void ArrayKlass::array_klasses_do(void f(Klass* k)) {
166 Klass* k = this;
167 // Iterate over this array klass and all higher dimensions
168 while (k != NULL) {
169 f(k);
170 k = ArrayKlass::cast(k)->higher_dimension();
171 }
172 }
173
174 // GC support
175
176 void ArrayKlass::oops_do(OopClosure* cl) {
177 Klass::oops_do(cl);
178
179 cl->do_oop(adr_component_mirror());
180 }
181
182 // JVM support
183
184 jint ArrayKlass::compute_modifier_flags(TRAPS) const {
185 return JVM_ACC_ABSTRACT | JVM_ACC_FINAL | JVM_ACC_PUBLIC;
186 }
187
188 // JVMTI support
189
190 jint ArrayKlass::jvmti_class_status() const {
191 return JVMTI_CLASS_STATUS_ARRAY;
192 }
193
194 void ArrayKlass::remove_unshareable_info() {
195 Klass::remove_unshareable_info();
196 // Clear the java mirror
197 set_component_mirror(NULL);
198 }
199
200 void ArrayKlass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) {
201 assert(loader_data == ClassLoaderData::the_null_class_loader_data(), "array classes belong to null loader");
202 Klass::restore_unshareable_info(loader_data, protection_domain, CHECK);
203 // Klass recreates the component mirror also
204 }
205
206 // Printing
207
208 void ArrayKlass::print_on(outputStream* st) const {
209 assert(is_klass(), "must be klass");
210 Klass::print_on(st);
211 }
212
213 void ArrayKlass::print_value_on(outputStream* st) const {
214 assert(is_klass(), "must be klass");
215 for(int index = 0; index < dimension(); index++) {
216 st->print("[]");
217 }
218 }
219
220 void ArrayKlass::oop_print_on(oop obj, outputStream* st) {
221 assert(obj->is_array(), "must be array");
222 Klass::oop_print_on(obj, st);
223 st->print_cr(" - length: %d", arrayOop(obj)->length());
224 }
225
226
227 // Verification
228
229 void ArrayKlass::verify_on(outputStream* st) {
230 Klass::verify_on(st);
231
232 if (component_mirror() != NULL) {
233 guarantee(component_mirror()->klass() != NULL, "should have a class");
234 }
235 }
236
237 void ArrayKlass::oop_verify_on(oop obj, outputStream* st) {
238 guarantee(obj->is_array(), "must be array");
239 arrayOop a = arrayOop(obj);
240 guarantee(a->length() >= 0, "array with negative length?");
241 }