1 /* 2 * Copyright (c) 1997, 2015, 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 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(int* vtable_length, 88 int* num_new_mirandas, 89 GrowableArray<Method*>* all_mirandas, 90 const Klass* super, 91 Array<Method*>* methods, 92 AccessFlags class_flags, 93 Handle classloader, 94 Symbol* classname, 95 Array<Klass*>* local_interfaces, 96 TRAPS); 97 98 #if INCLUDE_JVMTI 99 // RedefineClasses() API support: 100 // If any entry of this vtable points to any of old_methods, 101 // replace it with the corresponding new_method. 102 // trace_name_printed is set to true if the current call has 103 // printed the klass name so that other routines in the adjust_* 104 // group don't print the klass name. 105 bool adjust_default_method(int vtable_index, Method* old_method, Method* new_method); 106 void adjust_method_entries(InstanceKlass* holder, bool * trace_name_printed); 107 bool check_no_old_or_obsolete_entries(); 108 void dump_vtable(); 109 #endif // INCLUDE_JVMTI 110 111 // Debugging code 112 void print() PRODUCT_RETURN; 113 void verify(outputStream* st, bool force = false); 114 static void print_statistics() PRODUCT_RETURN; 115 116 protected: 117 friend class vtableEntry; 118 private: 119 enum { VTABLE_TRANSITIVE_OVERRIDE_VERSION = 51 } ; 120 void copy_vtable_to(vtableEntry* start); 121 int initialize_from_super(KlassHandle super); 122 int index_of(Method* m, int len) const; // same as index_of, but search only up to len 123 void put_method_at(Method* m, int index); 124 static bool needs_new_vtable_entry(methodHandle m, 125 const Klass* super, 126 Handle classloader, 127 Symbol* classname, 128 AccessFlags access_flags, 129 TRAPS); 130 131 bool update_inherited_vtable(InstanceKlass* klass, methodHandle target_method, int super_vtable_len, int default_index, bool checkconstraints, TRAPS); 132 InstanceKlass* find_transitive_override(InstanceKlass* initialsuper, methodHandle target_method, int vtable_index, 133 Handle target_loader, Symbol* target_classname, Thread* THREAD); 134 135 // support for miranda methods 136 bool is_miranda_entry_at(int i); 137 int fill_in_mirandas(int initialized); 138 static bool is_miranda(Method* m, Array<Method*>* class_methods, 139 Array<Method*>* default_methods, const Klass* super); 140 static void add_new_mirandas_to_lists( 141 GrowableArray<Method*>* new_mirandas, 142 GrowableArray<Method*>* all_mirandas, 143 Array<Method*>* current_interface_methods, 144 Array<Method*>* class_methods, 145 Array<Method*>* default_methods, 146 const Klass* super); 147 static void get_mirandas( 148 GrowableArray<Method*>* new_mirandas, 149 GrowableArray<Method*>* all_mirandas, 150 const Klass* super, 151 Array<Method*>* class_methods, 152 Array<Method*>* default_methods, 153 Array<Klass*>* local_interfaces); 154 void verify_against(outputStream* st, klassVtable* vt, int index); 155 inline InstanceKlass* ik() const; 156 }; 157 158 159 // private helper class for klassVtable 160 // description of entry points: 161 // destination is interpreted: 162 // from_compiled_code_entry_point -> c2iadapter 163 // from_interpreter_entry_point -> interpreter entry point 164 // destination is compiled: 165 // from_compiled_code_entry_point -> nmethod entry point 166 // from_interpreter_entry_point -> i2cadapter 167 class vtableEntry VALUE_OBJ_CLASS_SPEC { 168 friend class VMStructs; 169 170 public: 171 // size in words 172 static int size() { 173 return sizeof(vtableEntry) / sizeof(HeapWord); 174 } 175 static int method_offset_in_bytes() { return offset_of(vtableEntry, _method); } 176 Method* method() const { return _method; } 177 178 private: 179 Method* _method; 180 void set(Method* method) { assert(method != NULL, "use clear"); _method = method; } 181 void clear() { _method = NULL; } 182 void print() PRODUCT_RETURN; 183 void verify(klassVtable* vt, outputStream* st); 184 185 friend class klassVtable; 186 }; 187 188 189 inline Method* klassVtable::method_at(int i) const { 190 assert(i >= 0 && i < _length, "index out of bounds"); 191 assert(table()[i].method() != NULL, "should not be null"); 192 assert(((Metadata*)table()[i].method())->is_method(), "should be method"); 193 return table()[i].method(); 194 } 195 196 inline Method* klassVtable::unchecked_method_at(int i) const { 197 assert(i >= 0 && i < _length, "index out of bounds"); 198 return table()[i].method(); 199 } 200 201 inline Method** klassVtable::adr_method_at(int i) const { 202 // Allow one past the last entry to be referenced; useful for loop bounds. 203 assert(i >= 0 && i <= _length, "index out of bounds"); 204 return (Method**)(address(table() + i) + vtableEntry::method_offset_in_bytes()); 205 } 206 207 // -------------------------------------------------------------------------------- 208 class klassItable; 209 class itableMethodEntry; 210 211 class itableOffsetEntry VALUE_OBJ_CLASS_SPEC { 212 private: 213 Klass* _interface; 214 int _offset; 215 public: 216 Klass* interface_klass() const { return _interface; } 217 int offset() const { return _offset; } 218 219 static itableMethodEntry* method_entry(Klass* k, int offset) { return (itableMethodEntry*)(((address)k) + offset); } 220 itableMethodEntry* first_method_entry(Klass* k) { return method_entry(k, _offset); } 221 222 void initialize(Klass* interf, int offset) { _interface = interf; _offset = offset; } 223 224 // Static size and offset accessors 225 static int size() { return sizeof(itableOffsetEntry) / HeapWordSize; } // size in words 226 static int interface_offset_in_bytes() { return offset_of(itableOffsetEntry, _interface); } 227 static int offset_offset_in_bytes() { return offset_of(itableOffsetEntry, _offset); } 228 229 friend class klassItable; 230 }; 231 232 233 class itableMethodEntry VALUE_OBJ_CLASS_SPEC { 234 private: 235 Method* _method; 236 237 public: 238 Method* method() const { return _method; } 239 240 void clear() { _method = NULL; } 241 242 void initialize(Method* method); 243 244 // Static size and offset accessors 245 static int size() { return sizeof(itableMethodEntry) / HeapWordSize; } // size in words 246 static int method_offset_in_bytes() { return offset_of(itableMethodEntry, _method); } 247 248 friend class klassItable; 249 }; 250 251 // 252 // Format of an itable 253 // 254 // ---- offset table --- 255 // Klass* of interface 1 \ 256 // offset to vtable from start of oop / offset table entry 257 // ... 258 // Klass* of interface n \ 259 // offset to vtable from start of oop / offset table entry 260 // --- vtable for interface 1 --- 261 // Method* \ 262 // compiler entry point / method table entry 263 // ... 264 // Method* \ 265 // compiler entry point / method table entry 266 // -- vtable for interface 2 --- 267 // ... 268 // 269 class klassItable : public ResourceObj { 270 private: 271 instanceKlassHandle _klass; // my klass 272 int _table_offset; // offset of start of itable data within klass (in words) 273 int _size_offset_table; // size of offset table (in itableOffset entries) 274 int _size_method_table; // size of methodtable (in itableMethodEntry entries) 275 276 void initialize_itable_for_interface(int method_table_offset, KlassHandle interf_h, bool checkconstraints, TRAPS); 277 public: 278 klassItable(instanceKlassHandle klass); 279 280 itableOffsetEntry* offset_entry(int i) { assert(0 <= i && i <= _size_offset_table, "index out of bounds"); 281 return &((itableOffsetEntry*)vtable_start())[i]; } 282 283 itableMethodEntry* method_entry(int i) { assert(0 <= i && i <= _size_method_table, "index out of bounds"); 284 return &((itableMethodEntry*)method_start())[i]; } 285 286 int size_offset_table() { return _size_offset_table; } 287 288 // Initialization 289 void initialize_itable(bool checkconstraints, TRAPS); 290 291 // Updates 292 void initialize_with_method(Method* m); 293 294 #if INCLUDE_JVMTI 295 // RedefineClasses() API support: 296 // if any entry of this itable points to any of old_methods, 297 // replace it with the corresponding new_method. 298 // trace_name_printed is set to true if the current call has 299 // printed the klass name so that other routines in the adjust_* 300 // group don't print the klass name. 301 void adjust_method_entries(InstanceKlass* holder, bool * trace_name_printed); 302 bool check_no_old_or_obsolete_entries(); 303 void dump_itable(); 304 #endif // INCLUDE_JVMTI 305 306 // Setup of itable 307 static int assign_itable_indices_for_interface(Klass* klass); 308 static int method_count_for_interface(Klass* klass); 309 static int compute_itable_size(Array<Klass*>* transitive_interfaces); 310 static void setup_itable_offset_table(instanceKlassHandle klass); 311 312 // Resolving of method to index 313 static Method* method_for_itable_index(Klass* klass, int itable_index); 314 315 // Debugging/Statistics 316 static void print_statistics() PRODUCT_RETURN; 317 private: 318 intptr_t* vtable_start() const { return ((intptr_t*)_klass()) + _table_offset; } 319 intptr_t* method_start() const { return vtable_start() + _size_offset_table * itableOffsetEntry::size(); } 320 321 // Helper methods 322 static int calc_itable_size(int num_interfaces, int num_methods) { return (num_interfaces * itableOffsetEntry::size()) + (num_methods * itableMethodEntry::size()); } 323 324 // Statistics 325 NOT_PRODUCT(static int _total_classes;) // Total no. of classes with itables 326 NOT_PRODUCT(static long _total_size;) // Total no. of bytes used for itables 327 328 static void update_stats(int size) PRODUCT_RETURN NOT_PRODUCT({ _total_classes++; _total_size += size; }) 329 }; 330 331 #endif // SHARE_VM_OOPS_KLASSVTABLE_HPP