arrayKlass.cpp revision 2062:3582bf76420e 
1/*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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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
40int 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
54klassOop 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
62oop arrayKlass::multi_allocate(int rank, jint* sizes, TRAPS) {
63  ShouldNotReachHere();
64  return NULL;
65}
66
67methodOop arrayKlass::uncached_lookup_method(Symbol* name, Symbol* 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
74arrayKlassHandle arrayKlass::base_create_array_klass(
75const 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.
116void 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
123objArrayOop 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
130bool 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
138inline 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
144klassVtable* 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
150objArrayOop 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
168void 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
178void arrayKlass::with_array_klasses_do(void f(klassOop k)) {
179  array_klasses_do(f);
180}
181
182// JVM support
183
184jint arrayKlass::compute_modifier_flags(TRAPS) const {
185  return JVM_ACC_ABSTRACT | JVM_ACC_FINAL | JVM_ACC_PUBLIC;
186}
187
188// JVMTI support
189
190jint arrayKlass::jvmti_class_status() const {
191  return JVMTI_CLASS_STATUS_ARRAY;
192}
193
194// Printing
195
196void 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
204void 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}
209