1 /*
2 * Copyright (c) 1997, 2011, 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).
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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,
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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 methodOop method_at(int i) const;
69 inline methodOop unchecked_method_at(int i) const;
70 inline oop* adr_method_at(int i) const;
71
72 // searching; all methods return -1 if not found
73 int index_of(methodOop 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(int &vtable_length, int &num_miranda_methods,
88 klassOop super, objArrayOop methods,
89 AccessFlags class_flags, Handle classloader,
90 Symbol* classname, objArrayOop local_interfaces,
91 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(methodOop* old_methods, methodOop* new_methods,
100 int methods_length, bool * trace_name_printed);
101
102 // Garbage collection
103 void oop_follow_contents();
104 void oop_adjust_pointers();
105
106 #ifndef SERIALGC
107 // Parallel Old
108 void oop_follow_contents(ParCompactionManager* cm);
109 void oop_update_pointers(ParCompactionManager* cm);
110 #endif // SERIALGC
111
112 // Iterators
113 void oop_oop_iterate(OopClosure* blk);
114 void oop_oop_iterate_m(OopClosure* blk, MemRegion mr);
115
116 // Debugging code
117 void print() PRODUCT_RETURN;
118 void verify(outputStream* st, bool force = false);
119 static void print_statistics() PRODUCT_RETURN;
120
121 #ifndef PRODUCT
122 bool check_no_old_entries();
123 void dump_vtable();
124 #endif
125
126 protected:
127 friend class vtableEntry;
128 private:
129 enum { VTABLE_TRANSITIVE_OVERRIDE_VERSION = 51 } ;
130 void copy_vtable_to(vtableEntry* start);
131 int initialize_from_super(KlassHandle super);
132 int index_of(methodOop m, int len) const; // same as index_of, but search only up to len
133 void put_method_at(methodOop m, int index);
134 static bool needs_new_vtable_entry(methodHandle m, klassOop super, Handle classloader, Symbol* classname, AccessFlags access_flags, TRAPS);
135
136 bool update_inherited_vtable(instanceKlass* klass, methodHandle target_method, int super_vtable_len, bool checkconstraints, TRAPS);
137 instanceKlass* find_transitive_override(instanceKlass* initialsuper, methodHandle target_method, int vtable_index,
138 Handle target_loader, Symbol* target_classname, Thread* THREAD);
139
140 // support for miranda methods
141 bool is_miranda_entry_at(int i);
142 void fill_in_mirandas(int& initialized);
143 static bool is_miranda(methodOop m, objArrayOop class_methods, klassOop super);
144 static void add_new_mirandas_to_list(GrowableArray<methodOop>* list_of_current_mirandas, objArrayOop current_interface_methods, objArrayOop class_methods, klassOop super);
145 static void get_mirandas(GrowableArray<methodOop>* mirandas, klassOop super, objArrayOop class_methods, objArrayOop local_interfaces);
146 static int get_num_mirandas(klassOop super, objArrayOop class_methods, objArrayOop local_interfaces);
147
148
149 void verify_against(outputStream* st, klassVtable* vt, int index);
150 inline instanceKlass* ik() const;
151 };
152
153
154 // private helper class for klassVtable
155 // description of entry points:
156 // destination is interpreted:
157 // from_compiled_code_entry_point -> c2iadapter
158 // from_interpreter_entry_point -> interpreter entry point
159 // destination is compiled:
160 // from_compiled_code_entry_point -> nmethod entry point
161 // from_interpreter_entry_point -> i2cadapter
162 class vtableEntry VALUE_OBJ_CLASS_SPEC {
163 public:
164 // size in words
165 static int size() {
166 return sizeof(vtableEntry) / sizeof(HeapWord);
167 }
168 static int method_offset_in_bytes() { return offset_of(vtableEntry, _method); }
169 methodOop method() const { return _method; }
170
171 private:
172 methodOop _method;
173 void set(methodOop method) { assert(method != NULL, "use clear"); _method = method; }
174 void clear() { _method = NULL; }
175 void print() PRODUCT_RETURN;
176 void verify(klassVtable* vt, outputStream* st);
177
178 friend class klassVtable;
179 };
180
181
182 inline methodOop klassVtable::method_at(int i) const {
183 assert(i >= 0 && i < _length, "index out of bounds");
184 assert(table()[i].method() != NULL, "should not be null");
185 assert(oop(table()[i].method())->is_method(), "should be method");
186 return table()[i].method();
187 }
188
189 inline methodOop klassVtable::unchecked_method_at(int i) const {
190 assert(i >= 0 && i < _length, "index out of bounds");
191 return table()[i].method();
192 }
193
194 inline oop* klassVtable::adr_method_at(int i) const {
195 // Allow one past the last entry to be referenced; useful for loop bounds.
196 assert(i >= 0 && i <= _length, "index out of bounds");
197 return (oop*)(address(table() + i) + vtableEntry::method_offset_in_bytes());
198 }
199
200 // --------------------------------------------------------------------------------
201 class klassItable;
202 class itableMethodEntry;
203
204 class itableOffsetEntry VALUE_OBJ_CLASS_SPEC {
205 private:
206 klassOop _interface;
207 int _offset;
208 public:
209 klassOop interface_klass() const { return _interface; }
210 int offset() const { return _offset; }
211
212 static itableMethodEntry* method_entry(klassOop k, int offset) { return (itableMethodEntry*)(((address)k) + offset); }
213 itableMethodEntry* first_method_entry(klassOop k) { return method_entry(k, _offset); }
214
215 void initialize(klassOop interf, int offset) { _interface = interf; _offset = offset; }
216
217 // Static size and offset accessors
218 static int size() { return sizeof(itableOffsetEntry) / HeapWordSize; } // size in words
219 static int interface_offset_in_bytes() { return offset_of(itableOffsetEntry, _interface); }
220 static int offset_offset_in_bytes() { return offset_of(itableOffsetEntry, _offset); }
221
222 friend class klassItable;
223 };
224
225
226 class itableMethodEntry VALUE_OBJ_CLASS_SPEC {
227 private:
228 methodOop _method;
229
230 public:
231 methodOop method() const { return _method; }
232
233 void clear() { _method = NULL; }
234
235 void initialize(methodOop method);
236
237 // Static size and offset accessors
238 static int size() { return sizeof(itableMethodEntry) / HeapWordSize; } // size in words
239 static int method_offset_in_bytes() { return offset_of(itableMethodEntry, _method); }
240
241 friend class klassItable;
242 };
243
244 //
245 // Format of an itable
246 //
247 // ---- offset table ---
248 // klassOop of interface 1 \
249 // offset to vtable from start of oop / offset table entry
250 // ...
251 // klassOop of interface n \
252 // offset to vtable from start of oop / offset table entry
253 // --- vtable for interface 1 ---
254 // methodOop \
255 // compiler entry point / method table entry
256 // ...
257 // methodOop \
258 // compiler entry point / method table entry
259 // -- vtable for interface 2 ---
260 // ...
261 //
262 class klassItable : public ResourceObj {
263 private:
264 instanceKlassHandle _klass; // my klass
265 int _table_offset; // offset of start of itable data within klass (in words)
266 int _size_offset_table; // size of offset table (in itableOffset entries)
267 int _size_method_table; // size of methodtable (in itableMethodEntry entries)
268
269 void initialize_itable_for_interface(int method_table_offset, KlassHandle interf_h, bool checkconstraints, TRAPS);
270 public:
271 klassItable(instanceKlassHandle klass);
272
273 itableOffsetEntry* offset_entry(int i) { assert(0 <= i && i <= _size_offset_table, "index out of bounds");
274 return &((itableOffsetEntry*)vtable_start())[i]; }
275
276 itableMethodEntry* method_entry(int i) { assert(0 <= i && i <= _size_method_table, "index out of bounds");
277 return &((itableMethodEntry*)method_start())[i]; }
278
279 int size_offset_table() { return _size_offset_table; }
280
281 // Initialization
282 void initialize_itable(bool checkconstraints, TRAPS);
283
284 // Updates
285 void initialize_with_method(methodOop m);
286
287 // RedefineClasses() API support:
288 // if any entry of this itable points to any of old_methods,
289 // replace it with the corresponding new_method.
290 // trace_name_printed is set to true if the current call has
291 // printed the klass name so that other routines in the adjust_*
292 // group don't print the klass name.
293 void adjust_method_entries(methodOop* old_methods, methodOop* new_methods,
294 int methods_length, bool * trace_name_printed);
295
296 // Garbage collection
297 void oop_follow_contents();
298 void oop_adjust_pointers();
299
300 #ifndef SERIALGC
301 // Parallel Old
302 void oop_follow_contents(ParCompactionManager* cm);
303 void oop_update_pointers(ParCompactionManager* cm);
304 #endif // SERIALGC
305
306 // Iterators
307 void oop_oop_iterate(OopClosure* blk);
308 void oop_oop_iterate_m(OopClosure* blk, MemRegion mr);
309
310 // Setup of itable
311 static int compute_itable_size(objArrayHandle transitive_interfaces);
312 static void setup_itable_offset_table(instanceKlassHandle klass);
313
314 // Resolving of method to index
315 static int compute_itable_index(methodOop m);
316 // ...and back again:
317 static methodOop method_for_itable_index(klassOop klass, int itable_index);
318
319 // Debugging/Statistics
320 static void print_statistics() PRODUCT_RETURN;
321 private:
322 intptr_t* vtable_start() const { return ((intptr_t*)_klass()) + _table_offset; }
323 intptr_t* method_start() const { return vtable_start() + _size_offset_table * itableOffsetEntry::size(); }
324
325 // Helper methods
326 static int calc_itable_size(int num_interfaces, int num_methods) { return (num_interfaces * itableOffsetEntry::size()) + (num_methods * itableMethodEntry::size()); }
327
328 // Statistics
329 NOT_PRODUCT(static int _total_classes;) // Total no. of classes with itables
330 NOT_PRODUCT(static long _total_size;) // Total no. of bytes used for itables
331
332 static void update_stats(int size) PRODUCT_RETURN NOT_PRODUCT({ _total_classes++; _total_size += size; })
333 };
334
335 #endif // SHARE_VM_OOPS_KLASSVTABLE_HPP