1 /*
2 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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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.
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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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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 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 bool check_no_old_or_obsolete_entries();
102 void dump_vtable();
103
104 // Debugging code
105 void print() PRODUCT_RETURN;
106 void verify(outputStream* st, bool force = false);
107 static void print_statistics() PRODUCT_RETURN;
108
109 protected:
110 friend class vtableEntry;
111 private:
112 enum { VTABLE_TRANSITIVE_OVERRIDE_VERSION = 51 } ;
113 void copy_vtable_to(vtableEntry* start);
114 int initialize_from_super(KlassHandle super);
115 int index_of(Method* m, int len) const; // same as index_of, but search only up to len
116 void put_method_at(Method* m, int index);
117 static bool needs_new_vtable_entry(methodHandle m, Klass* super, Handle classloader, Symbol* classname, AccessFlags access_flags, TRAPS);
118
119 bool update_inherited_vtable(InstanceKlass* klass, methodHandle target_method, int super_vtable_len, bool checkconstraints, TRAPS);
120 InstanceKlass* find_transitive_override(InstanceKlass* initialsuper, methodHandle target_method, int vtable_index,
121 Handle target_loader, Symbol* target_classname, Thread* THREAD);
122
123 // support for miranda methods
124 bool is_miranda_entry_at(int i);
125 void fill_in_mirandas(int* initialized);
126 static bool is_miranda(Method* m, Array<Method*>* class_methods, Klass* super);
127 static void add_new_mirandas_to_lists(
128 GrowableArray<Method*>* new_mirandas,
129 GrowableArray<Method*>* all_mirandas,
130 Array<Method*>* current_interface_methods, Array<Method*>* class_methods,
131 Klass* super);
132 static void get_mirandas(
133 GrowableArray<Method*>* new_mirandas,
134 GrowableArray<Method*>* all_mirandas, Klass* super,
135 Array<Method*>* class_methods, Array<Klass*>* local_interfaces);
136
137 void verify_against(outputStream* st, klassVtable* vt, int index);
138 inline InstanceKlass* ik() const;
139 };
140
141
142 // private helper class for klassVtable
143 // description of entry points:
144 // destination is interpreted:
145 // from_compiled_code_entry_point -> c2iadapter
146 // from_interpreter_entry_point -> interpreter entry point
147 // destination is compiled:
148 // from_compiled_code_entry_point -> nmethod entry point
149 // from_interpreter_entry_point -> i2cadapter
150 class vtableEntry VALUE_OBJ_CLASS_SPEC {
151 public:
152 // size in words
153 static int size() {
154 return sizeof(vtableEntry) / sizeof(HeapWord);
155 }
156 static int method_offset_in_bytes() { return offset_of(vtableEntry, _method); }
157 Method* method() const { return _method; }
158
159 private:
160 Method* _method;
161 void set(Method* method) { assert(method != NULL, "use clear"); _method = method; }
162 void clear() { _method = NULL; }
163 void print() PRODUCT_RETURN;
164 void verify(klassVtable* vt, outputStream* st);
165
166 friend class klassVtable;
167 };
168
169
170 inline Method* klassVtable::method_at(int i) const {
171 assert(i >= 0 && i < _length, "index out of bounds");
172 assert(table()[i].method() != NULL, "should not be null");
173 assert(((Metadata*)table()[i].method())->is_method(), "should be method");
174 return table()[i].method();
175 }
176
177 inline Method* klassVtable::unchecked_method_at(int i) const {
178 assert(i >= 0 && i < _length, "index out of bounds");
179 return table()[i].method();
180 }
181
182 inline Method** klassVtable::adr_method_at(int i) const {
183 // Allow one past the last entry to be referenced; useful for loop bounds.
184 assert(i >= 0 && i <= _length, "index out of bounds");
185 return (Method**)(address(table() + i) + vtableEntry::method_offset_in_bytes());
186 }
187
188 // --------------------------------------------------------------------------------
189 class klassItable;
190 class itableMethodEntry;
191
192 class itableOffsetEntry VALUE_OBJ_CLASS_SPEC {
193 private:
194 Klass* _interface;
195 int _offset;
196 public:
197 Klass* interface_klass() const { return _interface; }
198 int offset() const { return _offset; }
199
200 static itableMethodEntry* method_entry(Klass* k, int offset) { return (itableMethodEntry*)(((address)k) + offset); }
201 itableMethodEntry* first_method_entry(Klass* k) { return method_entry(k, _offset); }
202
203 void initialize(Klass* interf, int offset) { _interface = interf; _offset = offset; }
204
205 // Static size and offset accessors
206 static int size() { return sizeof(itableOffsetEntry) / HeapWordSize; } // size in words
207 static int interface_offset_in_bytes() { return offset_of(itableOffsetEntry, _interface); }
208 static int offset_offset_in_bytes() { return offset_of(itableOffsetEntry, _offset); }
209
210 friend class klassItable;
211 };
212
213
214 class itableMethodEntry VALUE_OBJ_CLASS_SPEC {
215 private:
216 Method* _method;
217
218 public:
219 Method* method() const { return _method; }
220
221 void clear() { _method = NULL; }
222
223 void initialize(Method* method);
224
225 // Static size and offset accessors
226 static int size() { return sizeof(itableMethodEntry) / HeapWordSize; } // size in words
227 static int method_offset_in_bytes() { return offset_of(itableMethodEntry, _method); }
228
229 friend class klassItable;
230 };
231
232 //
233 // Format of an itable
234 //
235 // ---- offset table ---
236 // Klass* of interface 1 \
237 // offset to vtable from start of oop / offset table entry
238 // ...
239 // Klass* of interface n \
240 // offset to vtable from start of oop / offset table entry
241 // --- vtable for interface 1 ---
242 // Method* \
243 // compiler entry point / method table entry
244 // ...
245 // Method* \
246 // compiler entry point / method table entry
247 // -- vtable for interface 2 ---
248 // ...
249 //
250 class klassItable : public ResourceObj {
251 private:
252 instanceKlassHandle _klass; // my klass
253 int _table_offset; // offset of start of itable data within klass (in words)
254 int _size_offset_table; // size of offset table (in itableOffset entries)
255 int _size_method_table; // size of methodtable (in itableMethodEntry entries)
256
257 void initialize_itable_for_interface(int method_table_offset, KlassHandle interf_h, bool checkconstraints, TRAPS);
258 public:
259 klassItable(instanceKlassHandle klass);
260
261 itableOffsetEntry* offset_entry(int i) { assert(0 <= i && i <= _size_offset_table, "index out of bounds");
262 return &((itableOffsetEntry*)vtable_start())[i]; }
263
264 itableMethodEntry* method_entry(int i) { assert(0 <= i && i <= _size_method_table, "index out of bounds");
265 return &((itableMethodEntry*)method_start())[i]; }
266
267 int size_offset_table() { return _size_offset_table; }
268
269 // Initialization
270 void initialize_itable(bool checkconstraints, TRAPS);
271
272 // Updates
273 void initialize_with_method(Method* m);
274
275 // RedefineClasses() API support:
276 // if any entry of this itable points to any of old_methods,
277 // replace it with the corresponding new_method.
278 // trace_name_printed is set to true if the current call has
279 // printed the klass name so that other routines in the adjust_*
280 // group don't print the klass name.
281 void adjust_method_entries(Method** old_methods, Method** new_methods,
282 int methods_length, bool * trace_name_printed);
283 bool check_no_old_or_obsolete_entries();
284 void dump_itable();
285
286 // Setup of itable
287 static int compute_itable_size(Array<Klass*>* transitive_interfaces);
288 static void setup_itable_offset_table(instanceKlassHandle klass);
289
290 // Resolving of method to index
291 static int compute_itable_index(Method* m);
292 // ...and back again:
293 static Method* method_for_itable_index(Klass* klass, int itable_index);
294
295 // Debugging/Statistics
296 static void print_statistics() PRODUCT_RETURN;
297 private:
298 intptr_t* vtable_start() const { return ((intptr_t*)_klass()) + _table_offset; }
299 intptr_t* method_start() const { return vtable_start() + _size_offset_table * itableOffsetEntry::size(); }
300
301 // Helper methods
302 static int calc_itable_size(int num_interfaces, int num_methods) { return (num_interfaces * itableOffsetEntry::size()) + (num_methods * itableMethodEntry::size()); }
303
304 // Statistics
305 NOT_PRODUCT(static int _total_classes;) // Total no. of classes with itables
306 NOT_PRODUCT(static long _total_size;) // Total no. of bytes used for itables
307
308 static void update_stats(int size) PRODUCT_RETURN NOT_PRODUCT({ _total_classes++; _total_size += size; })
309 };
310
311 #endif // SHARE_VM_OOPS_KLASSVTABLE_HPP