1 /*
2 * Copyright (c) 1997, 2012, 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
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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.
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23 */
24
25 #ifndef SHARE_VM_OOPS_KLASSVTABLE_HPP
26 #define SHARE_VM_OOPS_KLASSVTABLE_HPP
27
28 #include "memory/allocation.hpp"
29 #include "oops/oopsHierarchy.hpp"
30 #include "runtime/handles.hpp"
31 #include "utilities/growableArray.hpp"
32
33 // A klassVtable abstracts the variable-length vtable that is embedded in InstanceKlass
34 // and ArrayKlass. klassVtable objects are used just as convenient transient accessors to the vtable,
35 // not to actually hold the vtable data.
36 // Note: the klassVtable should not be accessed before the class has been verified
37 // (until that point, the vtable is uninitialized).
38
39 // Currently a klassVtable contains a direct reference to the vtable data, and is therefore
40 // not preserved across GCs.
41
42 class vtableEntry;
43
44 class klassVtable : public ResourceObj {
45 KlassHandle _klass; // my klass
46 int _tableOffset; // offset of start of vtable data within klass
47 int _length; // length of vtable (number of entries)
48 #ifndef PRODUCT
49 int _verify_count; // to make verify faster
50 #endif
51
52 // Ordering important, so greater_than (>) can be used as an merge operator.
53 enum AccessType {
54 acc_private = 0,
55 acc_package_private = 1,
56 acc_publicprotected = 2
57 };
58
59 public:
60 klassVtable(KlassHandle h_klass, void* base, int length) : _klass(h_klass) {
61 _tableOffset = (address)base - (address)h_klass(); _length = length;
62 }
63
64 // accessors
65 vtableEntry* table() const { return (vtableEntry*)(address(_klass()) + _tableOffset); }
66 KlassHandle klass() const { return _klass; }
67 int length() const { return _length; }
68 inline Method* method_at(int i) const;
69 inline Method* unchecked_method_at(int i) const;
70 inline Method** adr_method_at(int i) const;
71
72 // searching; all methods return -1 if not found
73 int index_of(Method* m) const { return index_of(m, _length); }
74 int index_of_miranda(Symbol* name, Symbol* signature);
75
76 void initialize_vtable(bool checkconstraints, TRAPS); // initialize vtable of a new klass
77
78 // CDS/RedefineClasses support - clear vtables so they can be reinitialized
79 // at dump time. Clearing gives us an easy way to tell if the vtable has
80 // already been reinitialized at dump time (see dump.cpp). Vtables can
81 // be initialized at run time by RedefineClasses so dumping the right order
82 // is necessary.
83 void clear_vtable();
84 bool is_initialized();
85
86 // computes vtable length (in words) and the number of miranda methods
87 static void compute_vtable_size_and_num_mirandas(
88 int* vtable_length, int* num_new_mirandas,
89 GrowableArray<Method*>* all_mirandas, Klass* super,
90 Array<Method*>* methods, AccessFlags class_flags, Handle classloader,
91 Symbol* classname, Array<Klass*>* local_interfaces, TRAPS);
92
93 // RedefineClasses() API support:
94 // If any entry of this vtable points to any of old_methods,
95 // replace it with the corresponding new_method.
96 // trace_name_printed is set to true if the current call has
97 // printed the klass name so that other routines in the adjust_*
98 // group don't print the klass name.
99 void adjust_method_entries(Method** old_methods, Method** new_methods,
100 int methods_length, bool * trace_name_printed);
101
102 // Debugging code
103 void print() PRODUCT_RETURN;
104 void verify(outputStream* st, bool force = false);
105 static void print_statistics() PRODUCT_RETURN;
106
107 #ifndef PRODUCT
108 bool check_no_old_entries();
109 void dump_vtable();
110 #endif
111
112 protected:
113 friend class vtableEntry;
114 private:
115 enum { VTABLE_TRANSITIVE_OVERRIDE_VERSION = 51 } ;
116 void copy_vtable_to(vtableEntry* start);
117 int initialize_from_super(KlassHandle super);
118 int index_of(Method* m, int len) const; // same as index_of, but search only up to len
119 void put_method_at(Method* m, int index);
120 static bool needs_new_vtable_entry(methodHandle m, Klass* super, Handle classloader, Symbol* classname, AccessFlags access_flags, TRAPS);
121
122 bool update_inherited_vtable(InstanceKlass* klass, methodHandle target_method, int super_vtable_len, bool checkconstraints, TRAPS);
123 InstanceKlass* find_transitive_override(InstanceKlass* initialsuper, methodHandle target_method, int vtable_index,
124 Handle target_loader, Symbol* target_classname, Thread* THREAD);
125
126 // support for miranda methods
127 bool is_miranda_entry_at(int i);
128 void fill_in_mirandas(int* initialized);
129 static bool is_miranda(Method* m, Array<Method*>* class_methods, Klass* super);
130 static void add_new_mirandas_to_lists(
131 GrowableArray<Method*>* new_mirandas,
132 GrowableArray<Method*>* all_mirandas,
133 Array<Method*>* current_interface_methods, Array<Method*>* class_methods,
134 Klass* super);
135 static void get_mirandas(
136 GrowableArray<Method*>* new_mirandas,
137 GrowableArray<Method*>* all_mirandas, Klass* super,
138 Array<Method*>* class_methods, Array<Klass*>* local_interfaces);
139
140 void verify_against(outputStream* st, klassVtable* vt, int index);
141 inline InstanceKlass* ik() const;
142 };
143
144
145 // private helper class for klassVtable
146 // description of entry points:
147 // destination is interpreted:
148 // from_compiled_code_entry_point -> c2iadapter
149 // from_interpreter_entry_point -> interpreter entry point
150 // destination is compiled:
151 // from_compiled_code_entry_point -> nmethod entry point
152 // from_interpreter_entry_point -> i2cadapter
153 class vtableEntry VALUE_OBJ_CLASS_SPEC {
154 public:
155 // size in words
156 static int size() {
157 return sizeof(vtableEntry) / sizeof(HeapWord);
158 }
159 static int method_offset_in_bytes() { return offset_of(vtableEntry, _method); }
160 Method* method() const { return _method; }
161
162 private:
163 Method* _method;
164 void set(Method* method) { assert(method != NULL, "use clear"); _method = method; }
165 void clear() { _method = NULL; }
166 void print() PRODUCT_RETURN;
167 void verify(klassVtable* vt, outputStream* st);
168
169 friend class klassVtable;
170 };
171
172
173 inline Method* klassVtable::method_at(int i) const {
174 assert(i >= 0 && i < _length, "index out of bounds");
175 assert(table()[i].method() != NULL, "should not be null");
176 assert(((Metadata*)table()[i].method())->is_method(), "should be method");
177 return table()[i].method();
178 }
179
180 inline Method* klassVtable::unchecked_method_at(int i) const {
181 assert(i >= 0 && i < _length, "index out of bounds");
182 return table()[i].method();
183 }
184
185 inline Method** klassVtable::adr_method_at(int i) const {
186 // Allow one past the last entry to be referenced; useful for loop bounds.
187 assert(i >= 0 && i <= _length, "index out of bounds");
188 return (Method**)(address(table() + i) + vtableEntry::method_offset_in_bytes());
189 }
190
191 // --------------------------------------------------------------------------------
192 class klassItable;
193 class itableMethodEntry;
194
195 class itableOffsetEntry VALUE_OBJ_CLASS_SPEC {
196 private:
197 Klass* _interface;
198 int _offset;
199 public:
200 Klass* interface_klass() const { return _interface; }
201 int offset() const { return _offset; }
202
203 static itableMethodEntry* method_entry(Klass* k, int offset) { return (itableMethodEntry*)(((address)k) + offset); }
204 itableMethodEntry* first_method_entry(Klass* k) { return method_entry(k, _offset); }
205
206 void initialize(Klass* interf, int offset) { _interface = interf; _offset = offset; }
207
208 // Static size and offset accessors
209 static int size() { return sizeof(itableOffsetEntry) / HeapWordSize; } // size in words
210 static int interface_offset_in_bytes() { return offset_of(itableOffsetEntry, _interface); }
211 static int offset_offset_in_bytes() { return offset_of(itableOffsetEntry, _offset); }
212
213 friend class klassItable;
214 };
215
216
217 class itableMethodEntry VALUE_OBJ_CLASS_SPEC {
218 private:
219 Method* _method;
220
221 public:
222 Method* method() const { return _method; }
223
224 void clear() { _method = NULL; }
225
226 void initialize(Method* method);
227
228 // Static size and offset accessors
229 static int size() { return sizeof(itableMethodEntry) / HeapWordSize; } // size in words
230 static int method_offset_in_bytes() { return offset_of(itableMethodEntry, _method); }
231
232 friend class klassItable;
233 };
234
235 //
236 // Format of an itable
237 //
238 // ---- offset table ---
239 // Klass* of interface 1 \
240 // offset to vtable from start of oop / offset table entry
241 // ...
242 // Klass* of interface n \
243 // offset to vtable from start of oop / offset table entry
244 // --- vtable for interface 1 ---
245 // Method* \
246 // compiler entry point / method table entry
247 // ...
248 // Method* \
249 // compiler entry point / method table entry
250 // -- vtable for interface 2 ---
251 // ...
252 //
253 class klassItable : public ResourceObj {
254 private:
255 instanceKlassHandle _klass; // my klass
256 int _table_offset; // offset of start of itable data within klass (in words)
257 int _size_offset_table; // size of offset table (in itableOffset entries)
258 int _size_method_table; // size of methodtable (in itableMethodEntry entries)
259
260 void initialize_itable_for_interface(int method_table_offset, KlassHandle interf_h, bool checkconstraints, TRAPS);
261 public:
262 klassItable(instanceKlassHandle klass);
263
264 itableOffsetEntry* offset_entry(int i) { assert(0 <= i && i <= _size_offset_table, "index out of bounds");
265 return &((itableOffsetEntry*)vtable_start())[i]; }
266
267 itableMethodEntry* method_entry(int i) { assert(0 <= i && i <= _size_method_table, "index out of bounds");
268 return &((itableMethodEntry*)method_start())[i]; }
269
270 int size_offset_table() { return _size_offset_table; }
271
272 // Initialization
273 void initialize_itable(bool checkconstraints, TRAPS);
274
275 // Updates
276 void initialize_with_method(Method* m);
277
278 // RedefineClasses() API support:
279 // if any entry of this itable points to any of old_methods,
280 // replace it with the corresponding new_method.
281 // trace_name_printed is set to true if the current call has
282 // printed the klass name so that other routines in the adjust_*
283 // group don't print the klass name.
284 void adjust_method_entries(Method** old_methods, Method** new_methods,
285 int methods_length, bool * trace_name_printed);
286
287 // Setup of itable
288 static int compute_itable_size(Array<Klass*>* transitive_interfaces);
289 static void setup_itable_offset_table(instanceKlassHandle klass);
290
291 // Resolving of method to index
292 static int compute_itable_index(Method* m);
293 // ...and back again:
294 static Method* method_for_itable_index(Klass* klass, int itable_index);
295
296 // Debugging/Statistics
297 static void print_statistics() PRODUCT_RETURN;
298 private:
299 intptr_t* vtable_start() const { return ((intptr_t*)_klass()) + _table_offset; }
300 intptr_t* method_start() const { return vtable_start() + _size_offset_table * itableOffsetEntry::size(); }
301
302 // Helper methods
303 static int calc_itable_size(int num_interfaces, int num_methods) { return (num_interfaces * itableOffsetEntry::size()) + (num_methods * itableMethodEntry::size()); }
304
305 // Statistics
306 NOT_PRODUCT(static int _total_classes;) // Total no. of classes with itables
307 NOT_PRODUCT(static long _total_size;) // Total no. of bytes used for itables
308
309 static void update_stats(int size) PRODUCT_RETURN NOT_PRODUCT({ _total_classes++; _total_size += size; })
310
311 public:
312 #ifndef PRODUCT
313 bool check_no_old_entries();
314 #endif
315 };
316
317 #endif // SHARE_VM_OOPS_KLASSVTABLE_HPP