1 /*
2 * Copyright (c) 1997, 2010, 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/arrayKlassKlass.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::object_size(int header_size) const {
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 #ifdef _LP64
46 int size = header_size + align_object_offset(vtable_length());
47 #else
48 int size = header_size + vtable_length();
49 #endif
50 return align_object_size(size);
51 }
52
53
54 klassOop 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 methodOop arrayKlass::uncached_lookup_method(symbolOop name, symbolOop signature) 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 Klass::cast(super())->uncached_lookup_method(name, signature);
71 }
72
73
74 arrayKlassHandle arrayKlass::base_create_array_klass(
75 const Klass_vtbl& cplusplus_vtbl, int header_size, KlassHandle klass, TRAPS) {
76 // Allocation
77 // Note: because the Java vtable must start at the same offset in all klasses,
78 // we must insert filler fields into arrayKlass to make it the same size as instanceKlass.
79 // If this assert fails, add filler to instanceKlass to make it bigger.
80 assert(header_size <= instanceKlass::header_size(),
81 "array klasses must be same size as instanceKlass");
82 header_size = instanceKlass::header_size();
83 // Arrays don't add any new methods, so their vtable is the same size as
84 // the vtable of klass Object.
85 int vtable_size = Universe::base_vtable_size();
86 arrayKlassHandle k;
87 KlassHandle base_klass = Klass::base_create_klass(klass,
88 header_size + vtable_size,
89 cplusplus_vtbl, CHECK_(k));
90
91 // No safepoint should be possible until the handle's
92 // target below becomes parsable
93 No_Safepoint_Verifier no_safepoint;
94 k = arrayKlassHandle(THREAD, base_klass());
95
96 assert(!k()->is_parsable(), "not expecting parsability yet.");
97 k->set_super(Universe::is_bootstrapping() ? (klassOop)NULL : SystemDictionary::Object_klass());
98 k->set_layout_helper(Klass::_lh_neutral_value);
99 k->set_dimension(1);
100 k->set_higher_dimension(NULL);
101 k->set_lower_dimension(NULL);
102 k->set_component_mirror(NULL);
103 k->set_vtable_length(vtable_size);
104 k->set_is_cloneable(); // All arrays are considered to be cloneable (See JLS 20.1.5)
105
106 assert(k()->is_parsable(), "should be parsable here.");
107 // Make sure size calculation is right
108 assert(k()->size() == align_object_size(header_size + vtable_size), "wrong size for object");
109
110 return k;
111 }
112
113
114 // Initialization of vtables and mirror object is done separatly from base_create_array_klass,
115 // since a GC can happen. At this point all instance variables of the arrayKlass must be setup.
116 void arrayKlass::complete_create_array_klass(arrayKlassHandle k, KlassHandle super_klass, TRAPS) {
117 ResourceMark rm(THREAD);
118 k->initialize_supers(super_klass(), CHECK);
119 k->vtable()->initialize_vtable(false, CHECK);
120 java_lang_Class::create_mirror(k, CHECK);
121 }
122
123 objArrayOop arrayKlass::compute_secondary_supers(int num_extra_slots, TRAPS) {
124 // interfaces = { cloneable_klass, serializable_klass };
125 assert(num_extra_slots == 0, "sanity of primitive array type");
126 // Must share this for correct bootstrapping!
127 return Universe::the_array_interfaces_array();
128 }
129
130 bool arrayKlass::compute_is_subtype_of(klassOop k) {
131 // An array is a subtype of Serializable, Clonable, and Object
132 return k == SystemDictionary::Object_klass()
133 || k == SystemDictionary::Cloneable_klass()
134 || k == SystemDictionary::Serializable_klass();
135 }
136
137
138 inline intptr_t* arrayKlass::start_of_vtable() const {
139 // all vtables start at the same place, that's why we use instanceKlass::header_size here
140 return ((intptr_t*)as_klassOop()) + instanceKlass::header_size();
141 }
142
143
144 klassVtable* arrayKlass::vtable() const {
145 KlassHandle kh(Thread::current(), as_klassOop());
146 return new klassVtable(kh, start_of_vtable(), vtable_length() / vtableEntry::size());
147 }
148
149
150 objArrayOop arrayKlass::allocate_arrayArray(int n, int length, TRAPS) {
151 if (length < 0) {
152 THROW_0(vmSymbols::java_lang_NegativeArraySizeException());
153 }
154 if (length > arrayOopDesc::max_array_length(T_ARRAY)) {
155 report_java_out_of_memory("Requested array size exceeds VM limit");
156 THROW_OOP_0(Universe::out_of_memory_error_array_size());
157 }
158 int size = objArrayOopDesc::object_size(length);
159 klassOop k = array_klass(n+dimension(), CHECK_0);
160 arrayKlassHandle ak (THREAD, k);
161 objArrayOop o =
162 (objArrayOop)CollectedHeap::array_allocate(ak, size, length, CHECK_0);
163 // initialization to NULL not necessary, area already cleared
164 return o;
165 }
166
167
168 void arrayKlass::array_klasses_do(void f(klassOop k)) {
169 klassOop k = as_klassOop();
170 // Iterate over this array klass and all higher dimensions
171 while (k != NULL) {
172 f(k);
173 k = arrayKlass::cast(k)->higher_dimension();
174 }
175 }
176
177
178 void arrayKlass::with_array_klasses_do(void f(klassOop k)) {
179 array_klasses_do(f);
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 // Printing
195
196 void arrayKlass::oop_print_on(oop obj, outputStream* st) {
197 assert(obj->is_array(), "must be array");
198 Klass::oop_print_on(obj, st);
199 st->print_cr(" - length: %d", arrayOop(obj)->length());
200 }
201
202 // Verification
203
204 void arrayKlass::oop_verify_on(oop obj, outputStream* st) {
205 guarantee(obj->is_array(), "must be array");
206 arrayOop a = arrayOop(obj);
207 guarantee(a->length() >= 0, "array with negative length?");
208 }