1 /*
2 * Copyright (c) 1997, 2009, 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 // A klassVtable abstracts the variable-length vtable that is embedded in instanceKlass
26 // and arrayKlass. klassVtable objects are used just as convenient transient accessors to the vtable,
27 // not to actually hold the vtable data.
28 // Note: the klassVtable should not be accessed before the class has been verified
29 // (until that point, the vtable is uninitialized).
30
31 // Currently a klassVtable contains a direct reference to the vtable data, and is therefore
32 // not preserved across GCs.
33
34 class vtableEntry;
35
36 class klassVtable : public ResourceObj {
37 KlassHandle _klass; // my klass
38 int _tableOffset; // offset of start of vtable data within klass
39 int _length; // length of vtable (number of entries)
40 #ifndef PRODUCT
41 int _verify_count; // to make verify faster
42 #endif
43
44 // Ordering important, so greater_than (>) can be used as an merge operator.
45 enum AccessType {
46 acc_private = 0,
47 acc_package_private = 1,
48 acc_publicprotected = 2
49 };
50
51 public:
52 klassVtable(KlassHandle h_klass, void* base, int length) : _klass(h_klass) {
53 _tableOffset = (address)base - (address)h_klass(); _length = length;
54 }
55
56 // accessors
57 vtableEntry* table() const { return (vtableEntry*)(address(_klass()) + _tableOffset); }
58 KlassHandle klass() const { return _klass; }
59 int length() const { return _length; }
60 inline methodOop method_at(int i) const;
61 inline methodOop unchecked_method_at(int i) const;
62 inline oop* adr_method_at(int i) const;
63
64 // searching; all methods return -1 if not found
65 int index_of(methodOop m) const { return index_of(m, _length); }
66 int index_of_miranda(symbolOop name, symbolOop signature);
67
68 void initialize_vtable(bool checkconstraints, TRAPS); // initialize vtable of a new klass
69
70 // conputes vtable length (in words) and the number of miranda methods
71 static void compute_vtable_size_and_num_mirandas(int &vtable_length, int &num_miranda_methods,
72 klassOop super, objArrayOop methods,
73 AccessFlags class_flags, Handle classloader,
74 symbolHandle classname, objArrayOop local_interfaces,
75 TRAPS);
76
77 // RedefineClasses() API support:
78 // If any entry of this vtable points to any of old_methods,
79 // replace it with the corresponding new_method.
80 // trace_name_printed is set to true if the current call has
81 // printed the klass name so that other routines in the adjust_*
82 // group don't print the klass name.
83 void adjust_method_entries(methodOop* old_methods, methodOop* new_methods,
84 int methods_length, bool * trace_name_printed);
85
86 // Garbage collection
87 void oop_follow_contents();
88 void oop_adjust_pointers();
89
90 #ifndef SERIALGC
91 // Parallel Old
92 void oop_follow_contents(ParCompactionManager* cm);
93 void oop_update_pointers(ParCompactionManager* cm);
94 void oop_update_pointers(ParCompactionManager* cm,
95 HeapWord* beg_addr, HeapWord* end_addr);
96 #endif // SERIALGC
97
98 // Iterators
99 void oop_oop_iterate(OopClosure* blk);
100 void oop_oop_iterate_m(OopClosure* blk, MemRegion mr);
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(methodOop m, int len) const; // same as index_of, but search only up to len
119 void put_method_at(methodOop m, int index);
120 static bool needs_new_vtable_entry(methodHandle m, klassOop super, Handle classloader, symbolHandle 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, symbolHandle 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(methodOop m, objArrayOop class_methods, klassOop super);
130 static void add_new_mirandas_to_list(GrowableArray<methodOop>* list_of_current_mirandas, objArrayOop current_interface_methods, objArrayOop class_methods, klassOop super);
131 static void get_mirandas(GrowableArray<methodOop>* mirandas, klassOop super, objArrayOop class_methods, objArrayOop local_interfaces);
132 static int get_num_mirandas(klassOop super, objArrayOop class_methods, objArrayOop local_interfaces);
133
134
135 void verify_against(outputStream* st, klassVtable* vt, int index);
136 inline instanceKlass* ik() const;
137 };
138
139
140 // private helper class for klassVtable
141 // description of entry points:
142 // destination is interpreted:
143 // from_compiled_code_entry_point -> c2iadapter
144 // from_interpreter_entry_point -> interpreter entry point
145 // destination is compiled:
146 // from_compiled_code_entry_point -> nmethod entry point
147 // from_interpreter_entry_point -> i2cadapter
148 class vtableEntry VALUE_OBJ_CLASS_SPEC {
149 public:
150 // size in words
151 static int size() {
152 return sizeof(vtableEntry) / sizeof(HeapWord);
153 }
154 static int method_offset_in_bytes() { return offset_of(vtableEntry, _method); }
155 methodOop method() const { return _method; }
156
157 private:
158 methodOop _method;
159 void set(methodOop method) { assert(method != NULL, "use clear"); _method = method; }
160 void clear() { _method = NULL; }
161 void print() PRODUCT_RETURN;
162 void verify(klassVtable* vt, outputStream* st);
163
164 friend class klassVtable;
165 };
166
167
168 inline methodOop klassVtable::method_at(int i) const {
169 assert(i >= 0 && i < _length, "index out of bounds");
170 assert(table()[i].method() != NULL, "should not be null");
171 assert(oop(table()[i].method())->is_method(), "should be method");
172 return table()[i].method();
173 }
174
175 inline methodOop klassVtable::unchecked_method_at(int i) const {
176 assert(i >= 0 && i < _length, "index out of bounds");
177 return table()[i].method();
178 }
179
180 inline oop* klassVtable::adr_method_at(int i) const {
181 // Allow one past the last entry to be referenced; useful for loop bounds.
182 assert(i >= 0 && i <= _length, "index out of bounds");
183 return (oop*)(address(table() + i) + vtableEntry::method_offset_in_bytes());
184 }
185
186 // --------------------------------------------------------------------------------
187 class klassItable;
188 class itableMethodEntry;
189
190 class itableOffsetEntry VALUE_OBJ_CLASS_SPEC {
191 private:
192 klassOop _interface;
193 int _offset;
194 public:
195 klassOop interface_klass() const { return _interface; }
196 int offset() const { return _offset; }
197
198 static itableMethodEntry* method_entry(klassOop k, int offset) { return (itableMethodEntry*)(((address)k) + offset); }
199 itableMethodEntry* first_method_entry(klassOop k) { return method_entry(k, _offset); }
200
201 void initialize(klassOop interf, int offset) { _interface = interf; _offset = offset; }
202
203 // Static size and offset accessors
204 static int size() { return sizeof(itableOffsetEntry) / HeapWordSize; } // size in words
205 static int interface_offset_in_bytes() { return offset_of(itableOffsetEntry, _interface); }
206 static int offset_offset_in_bytes() { return offset_of(itableOffsetEntry, _offset); }
207
208 friend class klassItable;
209 };
210
211
212 class itableMethodEntry VALUE_OBJ_CLASS_SPEC {
213 private:
214 methodOop _method;
215
216 public:
217 methodOop method() const { return _method; }
218
219 void clear() { _method = NULL; }
220
221 void initialize(methodOop method);
222
223 // Static size and offset accessors
224 static int size() { return sizeof(itableMethodEntry) / HeapWordSize; } // size in words
225 static int method_offset_in_bytes() { return offset_of(itableMethodEntry, _method); }
226
227 friend class klassItable;
228 };
229
230 //
231 // Format of an itable
232 //
233 // ---- offset table ---
234 // klassOop of interface 1 \
235 // offset to vtable from start of oop / offset table entry
236 // ...
237 // klassOop of interface n \
238 // offset to vtable from start of oop / offset table entry
239 // --- vtable for interface 1 ---
240 // methodOop \
241 // compiler entry point / method table entry
242 // ...
243 // methodOop \
244 // compiler entry point / method table entry
245 // -- vtable for interface 2 ---
246 // ...
247 //
248 class klassItable : public ResourceObj {
249 private:
250 instanceKlassHandle _klass; // my klass
251 int _table_offset; // offset of start of itable data within klass (in words)
252 int _size_offset_table; // size of offset table (in itableOffset entries)
253 int _size_method_table; // size of methodtable (in itableMethodEntry entries)
254
255 void initialize_itable_for_interface(int method_table_offset, KlassHandle interf_h, bool checkconstraints, TRAPS);
256 public:
257 klassItable(instanceKlassHandle klass);
258
259 itableOffsetEntry* offset_entry(int i) { assert(0 <= i && i <= _size_offset_table, "index out of bounds");
260 return &((itableOffsetEntry*)vtable_start())[i]; }
261
262 itableMethodEntry* method_entry(int i) { assert(0 <= i && i <= _size_method_table, "index out of bounds");
263 return &((itableMethodEntry*)method_start())[i]; }
264
265 int size_offset_table() { return _size_offset_table; }
266
267 // Initialization
268 void initialize_itable(bool checkconstraints, TRAPS);
269
270 // Updates
271 void initialize_with_method(methodOop m);
272
273 // RedefineClasses() API support:
274 // if any entry of this itable points to any of old_methods,
275 // replace it with the corresponding new_method.
276 // trace_name_printed is set to true if the current call has
277 // printed the klass name so that other routines in the adjust_*
278 // group don't print the klass name.
279 void adjust_method_entries(methodOop* old_methods, methodOop* new_methods,
280 int methods_length, bool * trace_name_printed);
281
282 // Garbage collection
283 void oop_follow_contents();
284 void oop_adjust_pointers();
285
286 #ifndef SERIALGC
287 // Parallel Old
288 void oop_follow_contents(ParCompactionManager* cm);
289 void oop_update_pointers(ParCompactionManager* cm);
290 void oop_update_pointers(ParCompactionManager* cm,
291 HeapWord* beg_addr, HeapWord* end_addr);
292 #endif // SERIALGC
293
294 // Iterators
295 void oop_oop_iterate(OopClosure* blk);
296 void oop_oop_iterate_m(OopClosure* blk, MemRegion mr);
297
298 // Setup of itable
299 static int compute_itable_size(objArrayHandle transitive_interfaces);
300 static void setup_itable_offset_table(instanceKlassHandle klass);
301
302 // Resolving of method to index
303 static int compute_itable_index(methodOop m);
304 // ...and back again:
305 static methodOop method_for_itable_index(klassOop klass, int itable_index);
306
307 // Debugging/Statistics
308 static void print_statistics() PRODUCT_RETURN;
309 private:
310 intptr_t* vtable_start() const { return ((intptr_t*)_klass()) + _table_offset; }
311 intptr_t* method_start() const { return vtable_start() + _size_offset_table * itableOffsetEntry::size(); }
312
313 // Helper methods
314 static int calc_itable_size(int num_interfaces, int num_methods) { return (num_interfaces * itableOffsetEntry::size()) + (num_methods * itableMethodEntry::size()); }
315
316 // Statistics
317 NOT_PRODUCT(static int _total_classes;) // Total no. of classes with itables
318 NOT_PRODUCT(static long _total_size;) // Total no. of bytes used for itables
319
320 static void update_stats(int size) PRODUCT_RETURN NOT_PRODUCT({ _total_classes++; _total_size += size; })
321 };