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