1 /*
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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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13 * accompanied this code).
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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 #if INCLUDE_JVMTI
94 // RedefineClasses() API support:
95 // If any entry of this vtable points to any of old_methods,
96 // replace it with the corresponding new_method.
97 // trace_name_printed is set to true if the current call has
98 // printed the klass name so that other routines in the adjust_*
99 // group don't print the klass name.
100 bool adjust_default_method(int vtable_index, Method* old_method, Method* new_method);
101 void adjust_method_entries(InstanceKlass* holder, bool * trace_name_printed);
102 bool check_no_old_or_obsolete_entries();
103 void dump_vtable();
104 #endif // INCLUDE_JVMTI
105
106 // Debugging code
107 void print() PRODUCT_RETURN;
108 void verify(outputStream* st, bool force = false);
109 static void print_statistics() PRODUCT_RETURN;
110
111 protected:
112 friend class vtableEntry;
113 private:
114 enum { VTABLE_TRANSITIVE_OVERRIDE_VERSION = 51 } ;
115 void copy_vtable_to(vtableEntry* start);
116 int initialize_from_super(KlassHandle super);
117 int index_of(Method* m, int len) const; // same as index_of, but search only up to len
118 void log_vtables(int i, bool allocate_new, methodHandle target_method,
119 KlassHandle target_klass, Method* super_method,
120 Thread* thread) PRODUCT_RETURN;
121 void put_method_at(Method* m, int index);
122 static bool needs_new_vtable_entry(methodHandle m, Klass* super, Handle classloader, Symbol* classname, AccessFlags access_flags, TRAPS);
123
124 bool update_inherited_vtable(InstanceKlass* klass, methodHandle target_method, int super_vtable_len, int default_index, bool checkconstraints, TRAPS);
125 InstanceKlass* find_transitive_override(InstanceKlass* initialsuper, methodHandle target_method, int vtable_index,
126 Handle target_loader, Symbol* target_classname, Thread* THREAD);
127
128 // support for miranda methods
129 bool is_miranda_entry_at(int i);
130 int fill_in_mirandas(int initialized);
131 static bool is_miranda(Method* m, Array<Method*>* class_methods,
132 Array<Method*>* default_methods, Klass* super);
133 static void add_new_mirandas_to_lists(
134 GrowableArray<Method*>* new_mirandas,
135 GrowableArray<Method*>* all_mirandas,
136 Array<Method*>* current_interface_methods,
137 Array<Method*>* class_methods,
138 Array<Method*>* default_methods,
139 Klass* super);
140 static void get_mirandas(
141 GrowableArray<Method*>* new_mirandas,
142 GrowableArray<Method*>* all_mirandas, Klass* super,
143 Array<Method*>* class_methods,
144 Array<Method*>* default_methods,
145 Array<Klass*>* local_interfaces);
146 void verify_against(outputStream* st, klassVtable* vt, int index);
147 inline InstanceKlass* ik() const;
148 };
149
150
151 // private helper class for klassVtable
152 // description of entry points:
153 // destination is interpreted:
154 // from_compiled_code_entry_point -> c2iadapter
155 // from_interpreter_entry_point -> interpreter entry point
156 // destination is compiled:
157 // from_compiled_code_entry_point -> nmethod entry point
158 // from_interpreter_entry_point -> i2cadapter
159 class vtableEntry VALUE_OBJ_CLASS_SPEC {
160 friend class VMStructs;
161
162 public:
163 // size in words
164 static int size() {
165 return sizeof(vtableEntry) / sizeof(HeapWord);
166 }
167 static int method_offset_in_bytes() { return offset_of(vtableEntry, _method); }
168 Method* method() const { return _method; }
169
170 private:
171 Method* _method;
172 void set(Method* method) { assert(method != NULL, "use clear"); _method = method; }
173 void clear() { _method = NULL; }
174 void print() PRODUCT_RETURN;
175 void verify(klassVtable* vt, outputStream* st);
176
177 friend class klassVtable;
178 };
179
180
181 inline Method* klassVtable::method_at(int i) const {
182 assert(i >= 0 && i < _length, "index out of bounds");
183 assert(table()[i].method() != NULL, "should not be null");
184 assert(((Metadata*)table()[i].method())->is_method(), "should be method");
185 return table()[i].method();
186 }
187
188 inline Method* klassVtable::unchecked_method_at(int i) const {
189 assert(i >= 0 && i < _length, "index out of bounds");
190 return table()[i].method();
191 }
192
193 inline Method** klassVtable::adr_method_at(int i) const {
194 // Allow one past the last entry to be referenced; useful for loop bounds.
195 assert(i >= 0 && i <= _length, "index out of bounds");
196 return (Method**)(address(table() + i) + vtableEntry::method_offset_in_bytes());
197 }
198
199 // --------------------------------------------------------------------------------
200 class klassItable;
201 class itableMethodEntry;
202
203 class itableOffsetEntry VALUE_OBJ_CLASS_SPEC {
204 private:
205 Klass* _interface;
206 int _offset;
207 public:
208 Klass* interface_klass() const { return _interface; }
209 int offset() const { return _offset; }
210
211 static itableMethodEntry* method_entry(Klass* k, int offset) { return (itableMethodEntry*)(((address)k) + offset); }
212 itableMethodEntry* first_method_entry(Klass* k) { return method_entry(k, _offset); }
213
214 void initialize(Klass* interf, int offset) { _interface = interf; _offset = offset; }
215
216 // Static size and offset accessors
217 static int size() { return sizeof(itableOffsetEntry) / HeapWordSize; } // size in words
218 static int interface_offset_in_bytes() { return offset_of(itableOffsetEntry, _interface); }
219 static int offset_offset_in_bytes() { return offset_of(itableOffsetEntry, _offset); }
220
221 friend class klassItable;
222 };
223
224
225 class itableMethodEntry VALUE_OBJ_CLASS_SPEC {
226 private:
227 Method* _method;
228
229 public:
230 Method* method() const { return _method; }
231
232 void clear() { _method = NULL; }
233
234 void initialize(Method* method);
235
236 // Static size and offset accessors
237 static int size() { return sizeof(itableMethodEntry) / HeapWordSize; } // size in words
238 static int method_offset_in_bytes() { return offset_of(itableMethodEntry, _method); }
239
240 friend class klassItable;
241 };
242
243 //
244 // Format of an itable
245 //
246 // ---- offset table ---
247 // Klass* of interface 1 \
248 // offset to vtable from start of oop / offset table entry
249 // ...
250 // Klass* of interface n \
251 // offset to vtable from start of oop / offset table entry
252 // --- vtable for interface 1 ---
253 // Method* \
254 // compiler entry point / method table entry
255 // ...
256 // Method* \
257 // compiler entry point / method table entry
258 // -- vtable for interface 2 ---
259 // ...
260 //
261 class klassItable : public ResourceObj {
262 private:
263 instanceKlassHandle _klass; // my klass
264 int _table_offset; // offset of start of itable data within klass (in words)
265 int _size_offset_table; // size of offset table (in itableOffset entries)
266 int _size_method_table; // size of methodtable (in itableMethodEntry entries)
267
268 void initialize_itable_for_interface(int method_table_offset, KlassHandle interf_h, bool checkconstraints, TRAPS);
269 public:
270 klassItable(instanceKlassHandle klass);
271
272 itableOffsetEntry* offset_entry(int i) { assert(0 <= i && i <= _size_offset_table, "index out of bounds");
273 return &((itableOffsetEntry*)vtable_start())[i]; }
274
275 itableMethodEntry* method_entry(int i) { assert(0 <= i && i <= _size_method_table, "index out of bounds");
276 return &((itableMethodEntry*)method_start())[i]; }
277
278 int size_offset_table() { return _size_offset_table; }
279
280 // Initialization
281 void initialize_itable(bool checkconstraints, TRAPS);
282
283 // Updates
284 void initialize_with_method(Method* m);
285
286 #if INCLUDE_JVMTI
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(InstanceKlass* holder, bool * trace_name_printed);
294 bool check_no_old_or_obsolete_entries();
295 void dump_itable();
296 #endif // INCLUDE_JVMTI
297
298 // Setup of itable
299 static int assign_itable_indices_for_interface(Klass* klass);
300 static int method_count_for_interface(Klass* klass);
301 static int compute_itable_size(Array<Klass*>* transitive_interfaces);
302 static void setup_itable_offset_table(instanceKlassHandle klass);
303
304 // Resolving of method to index
305 static Method* method_for_itable_index(Klass* 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 };
322
323 #endif // SHARE_VM_OOPS_KLASSVTABLE_HPP