1 /*
2 * Copyright (c) 1997, 2023, 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/moduleEntry.hpp"
28 #include "classfile/symbolTable.hpp"
29 #include "classfile/vmClasses.hpp"
30 #include "classfile/vmSymbols.hpp"
31 #include "gc/shared/collectedHeap.inline.hpp"
32 #include "jvmtifiles/jvmti.h"
33 #include "memory/metaspaceClosure.hpp"
34 #include "memory/resourceArea.hpp"
35 #include "memory/universe.hpp"
36 #include "oops/arrayKlass.hpp"
37 #include "oops/objArrayKlass.hpp"
38 #include "oops/arrayOop.hpp"
39 #include "oops/instanceKlass.hpp"
40 #include "oops/klass.inline.hpp"
41 #include "oops/objArrayOop.hpp"
42 #include "oops/oop.inline.hpp"
43 #include "runtime/handles.inline.hpp"
44
45 int ArrayKlass::static_size(int header_size) {
46 // size of an array klass object
47 assert(header_size <= InstanceKlass::header_size(), "bad header size");
48 // If this assert fails, see comments in base_create_array_klass.
49 header_size = InstanceKlass::header_size();
50 int vtable_len = Universe::base_vtable_size();
51 int size = header_size + vtable_len;
52 return align_metadata_size(size);
53 }
54
55
56 InstanceKlass* ArrayKlass::java_super() const {
57 if (super() == nullptr) return nullptr; // bootstrap case
58 // Array klasses have primary supertypes which are not reported to Java.
59 // Example super chain: String[][] -> Object[][] -> Object[] -> Object
60 return vmClasses::Object_klass();
61 }
62
63
64 oop ArrayKlass::multi_allocate(int rank, jint* sizes, TRAPS) {
65 ShouldNotReachHere();
66 return nullptr;
67 }
68
69 // find field according to JVM spec 5.4.3.2, returns the klass in which the field is defined
70 Klass* ArrayKlass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
71 // There are no fields in an array klass but look to the super class (Object)
72 assert(super(), "super klass must be present");
73 return super()->find_field(name, sig, fd);
74 }
75
76 Method* ArrayKlass::uncached_lookup_method(const Symbol* name,
77 const Symbol* signature,
78 OverpassLookupMode overpass_mode,
79 PrivateLookupMode private_mode) const {
80 // There are no methods in an array klass but the super class (Object) has some
81 assert(super(), "super klass must be present");
82 // Always ignore overpass methods in superclasses, although technically the
83 // super klass of an array, (j.l.Object) should not have
84 // any overpass methods present.
85 return super()->uncached_lookup_method(name, signature, OverpassLookupMode::skip, private_mode);
86 }
87
88 ArrayKlass::ArrayKlass(Symbol* name, KlassKind kind) :
89 Klass(kind),
90 _dimension(1),
91 _higher_dimension(nullptr),
92 _lower_dimension(nullptr) {
93 // Arrays don't add any new methods, so their vtable is the same size as
94 // the vtable of klass Object.
95 set_vtable_length(Universe::base_vtable_size());
96 set_name(name);
97 set_super(Universe::is_bootstrapping() ? nullptr : vmClasses::Object_klass());
98 set_layout_helper(Klass::_lh_neutral_value);
99 set_is_cloneable(); // All arrays are considered to be cloneable (See JLS 20.1.5)
100 JFR_ONLY(INIT_ID(this);)
101 }
102
103 Symbol* ArrayKlass::create_element_klass_array_name(Klass* element_klass, bool qdesc, TRAPS) {
104 ResourceMark rm(THREAD);
105 Symbol* name = nullptr;
106 char *name_str = element_klass->name()->as_C_string();
107 int len = element_klass->name()->utf8_length();
108 char *new_str = NEW_RESOURCE_ARRAY(char, len + 4);
109 int idx = 0;
110 new_str[idx++] = JVM_SIGNATURE_ARRAY;
111 if (element_klass->is_instance_klass()) { // it could be an array or simple type
112 if (qdesc) {
113 new_str[idx++] = JVM_SIGNATURE_PRIMITIVE_OBJECT;
114 } else {
115 new_str[idx++] = JVM_SIGNATURE_CLASS;
116 }
117 }
118 memcpy(&new_str[idx], name_str, len * sizeof(char));
119 idx += len;
120 if (element_klass->is_instance_klass()) {
121 new_str[idx++] = JVM_SIGNATURE_ENDCLASS;
122 }
123 new_str[idx++] = '\0';
124 return SymbolTable::new_symbol(new_str);
125 }
126
127 // Initialization of vtables and mirror object is done separately from base_create_array_klass,
128 // since a GC can happen. At this point all instance variables of the ArrayKlass must be setup.
129 void ArrayKlass::complete_create_array_klass(ArrayKlass* k, Klass* super_klass, ModuleEntry* module_entry, TRAPS) {
130 k->initialize_supers(super_klass, nullptr, CHECK);
131 k->vtable().initialize_vtable();
132
133 // During bootstrapping, before java.base is defined, the module_entry may not be present yet.
134 // These classes will be put on a fixup list and their module fields will be patched once
135 // java.base is defined.
136 assert((module_entry != nullptr) || ((module_entry == nullptr) && !ModuleEntryTable::javabase_defined()),
137 "module entry not available post " JAVA_BASE_NAME " definition");
138 oop module = (module_entry != nullptr) ? module_entry->module() : (oop)nullptr;
139 java_lang_Class::create_mirror(k, Handle(THREAD, k->class_loader()), Handle(THREAD, module), Handle(), Handle(), CHECK);
140 }
141
142 GrowableArray<Klass*>* ArrayKlass::compute_secondary_supers(int num_extra_slots,
143 Array<InstanceKlass*>* transitive_interfaces) {
144 // interfaces = { cloneable_klass, serializable_klass };
145 assert(num_extra_slots == 0, "sanity of primitive array type");
146 assert(transitive_interfaces == nullptr, "sanity");
147 // Must share this for correct bootstrapping!
148 set_secondary_supers(Universe::the_array_interfaces_array());
149 return nullptr;
150 }
151
152 objArrayOop ArrayKlass::allocate_arrayArray(int n, int length, TRAPS) {
153 check_array_allocation_length(length, arrayOopDesc::max_array_length(T_ARRAY), CHECK_NULL);
154 size_t size = objArrayOopDesc::object_size(length);
155 Klass* k = array_klass(n+dimension(), CHECK_NULL);
156 ArrayKlass* ak = ArrayKlass::cast(k);
157 objArrayOop o = (objArrayOop)Universe::heap()->array_allocate(ak, size, length,
158 /* do_zero */ true, CHECK_NULL);
159 // initialization to null not necessary, area already cleared
160 return o;
161 }
162
163 oop ArrayKlass::component_mirror() const {
164 return java_lang_Class::component_mirror(java_mirror());
165 }
166
167 jint ArrayKlass::compute_modifier_flags() const {
168 return JVM_ACC_ABSTRACT | JVM_ACC_FINAL | JVM_ACC_PUBLIC;
169 }
170
171 // JVMTI support
172
173 jint ArrayKlass::jvmti_class_status() const {
174 return JVMTI_CLASS_STATUS_ARRAY;
175 }
176
177 void ArrayKlass::metaspace_pointers_do(MetaspaceClosure* it) {
178 Klass::metaspace_pointers_do(it);
179
180 ResourceMark rm;
181 log_trace(cds)("Iter(ArrayKlass): %p (%s)", this, external_name());
182
183 // need to cast away volatile
184 it->push((Klass**)&_higher_dimension);
185 it->push((Klass**)&_lower_dimension);
186 }
187
188 #if INCLUDE_CDS
189 void ArrayKlass::remove_unshareable_info() {
190 Klass::remove_unshareable_info();
191 if (_higher_dimension != nullptr) {
192 ArrayKlass *ak = ArrayKlass::cast(higher_dimension());
193 ak->remove_unshareable_info();
194 }
195 }
196
197 void ArrayKlass::remove_java_mirror() {
198 Klass::remove_java_mirror();
199 if (_higher_dimension != nullptr) {
200 ArrayKlass *ak = ArrayKlass::cast(higher_dimension());
201 ak->remove_java_mirror();
202 }
203 }
204
205 void ArrayKlass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) {
206 assert(loader_data == ClassLoaderData::the_null_class_loader_data(), "array classes belong to null loader");
207 Klass::restore_unshareable_info(loader_data, protection_domain, CHECK);
208 // Klass recreates the component mirror also
209
210 if (_higher_dimension != nullptr) {
211 ArrayKlass *ak = ArrayKlass::cast(higher_dimension());
212 ak->restore_unshareable_info(loader_data, protection_domain, CHECK);
213 }
214 }
215 #endif // INCLUDE_CDS
216
217 // Printing
218
219 void ArrayKlass::print_on(outputStream* st) const {
220 assert(is_klass(), "must be klass");
221 Klass::print_on(st);
222 }
223
224 void ArrayKlass::print_value_on(outputStream* st) const {
225 assert(is_klass(), "must be klass");
226 for(int index = 0; index < dimension(); index++) {
227 st->print("[]");
228 }
229 }
230
231 void ArrayKlass::oop_print_on(oop obj, outputStream* st) {
232 assert(obj->is_array(), "must be array");
233 Klass::oop_print_on(obj, st);
234 st->print_cr(" - length: %d", arrayOop(obj)->length());
235 }
236
237
238 // Verification
239
240 void ArrayKlass::verify_on(outputStream* st) {
241 Klass::verify_on(st);
242 }
243
244 void ArrayKlass::oop_verify_on(oop obj, outputStream* st) {
245 guarantee(obj->is_array(), "must be array");
246 arrayOop a = arrayOop(obj);
247 guarantee(a->length() >= 0, "array with negative length?");
248 }