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