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( 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 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, int default_index, 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 int fill_in_mirandas(int initialized); 128 static bool is_miranda(Method* m, Array<Method*>* class_methods, 129 Array<Method*>* default_methods, Klass* super); 130 static void add_new_mirandas_to_lists( 131 GrowableArray<Method*>* new_mirandas, 132 GrowableArray<Method*>* all_mirandas, 133 Array<Method*>* current_interface_methods, 134 Array<Method*>* class_methods, 135 Array<Method*>* default_methods, 136 Klass* super); 137 static void get_mirandas( 138 GrowableArray<Method*>* new_mirandas, 139 GrowableArray<Method*>* all_mirandas, Klass* super, 140 Array<Method*>* class_methods, 141 Array<Method*>* default_methods, 142 Array<Klass*>* local_interfaces); 143 void verify_against(outputStream* st, klassVtable* vt, int index); 144 inline InstanceKlass* ik() const; 145 }; 146 147 148 // private helper class for klassVtable 149 // description of entry points: 150 // destination is interpreted: 151 // from_compiled_code_entry_point -> c2iadapter 152 // from_interpreter_entry_point -> interpreter entry point 153 // destination is compiled: 154 // from_compiled_code_entry_point -> nmethod entry point 155 // from_interpreter_entry_point -> i2cadapter 156 class vtableEntry VALUE_OBJ_CLASS_SPEC { 157 friend class VMStructs; 158 159 public: 160 // size in words 161 static int size() { 162 return sizeof(vtableEntry) / sizeof(HeapWord); 163 } 164 static int method_offset_in_bytes() { return offset_of(vtableEntry, _method); } 165 Method* method() const { return _method; } 166 167 private: 168 Method* _method; 169 void set(Method* method) { assert(method != NULL, "use clear"); _method = method; } 170 void clear() { _method = NULL; } 171 void print() PRODUCT_RETURN; 172 void verify(klassVtable* vt, outputStream* st); 173 174 friend class klassVtable; 175 }; 176 177 178 inline Method* klassVtable::method_at(int i) const { 179 assert(i >= 0 && i < _length, "index out of bounds"); 180 assert(table()[i].method() != NULL, "should not be null"); 181 assert(((Metadata*)table()[i].method())->is_method(), "should be method"); 182 return table()[i].method(); 183 } 184 185 inline Method* klassVtable::unchecked_method_at(int i) const { 186 assert(i >= 0 && i < _length, "index out of bounds"); 187 return table()[i].method(); 188 } 189 190 inline Method** klassVtable::adr_method_at(int i) const { 191 // Allow one past the last entry to be referenced; useful for loop bounds. 192 assert(i >= 0 && i <= _length, "index out of bounds"); 193 return (Method**)(address(table() + i) + vtableEntry::method_offset_in_bytes()); 194 } 195 196 // -------------------------------------------------------------------------------- 197 class klassItable; 198 class itableMethodEntry; 199 200 class itableOffsetEntry VALUE_OBJ_CLASS_SPEC { 201 private: 202 Klass* _interface; 203 int _offset; 204 public: 205 Klass* interface_klass() const { return _interface; } 206 int offset() const { return _offset; } 207 208 static itableMethodEntry* method_entry(Klass* k, int offset) { return (itableMethodEntry*)(((address)k) + offset); } 209 itableMethodEntry* first_method_entry(Klass* k) { return method_entry(k, _offset); } 210 211 void initialize(Klass* interf, int offset) { _interface = interf; _offset = offset; } 212 213 // Static size and offset accessors 214 static int size() { return sizeof(itableOffsetEntry) / HeapWordSize; } // size in words 215 static int interface_offset_in_bytes() { return offset_of(itableOffsetEntry, _interface); } 216 static int offset_offset_in_bytes() { return offset_of(itableOffsetEntry, _offset); } 217 218 friend class klassItable; 219 }; 220 221 222 class itableMethodEntry VALUE_OBJ_CLASS_SPEC { 223 private: 224 Method* _method; 225 226 public: 227 Method* method() const { return _method; } 228 229 void clear() { _method = NULL; } 230 231 void initialize(Method* method); 232 233 // Static size and offset accessors 234 static int size() { return sizeof(itableMethodEntry) / HeapWordSize; } // size in words 235 static int method_offset_in_bytes() { return offset_of(itableMethodEntry, _method); } 236 237 friend class klassItable; 238 }; 239 240 // 241 // Format of an itable 242 // 243 // ---- offset table --- 244 // Klass* of interface 1 \ 245 // offset to vtable from start of oop / offset table entry 246 // ... 247 // Klass* of interface n \ 248 // offset to vtable from start of oop / offset table entry 249 // --- vtable for interface 1 --- 250 // Method* \ 251 // compiler entry point / method table entry 252 // ... 253 // Method* \ 254 // compiler entry point / method table entry 255 // -- vtable for interface 2 --- 256 // ... 257 // 258 class klassItable : public ResourceObj { 259 private: 260 instanceKlassHandle _klass; // my klass 261 int _table_offset; // offset of start of itable data within klass (in words) 262 int _size_offset_table; // size of offset table (in itableOffset entries) 263 int _size_method_table; // size of methodtable (in itableMethodEntry entries) 264 265 void initialize_itable_for_interface(int method_table_offset, KlassHandle interf_h, bool checkconstraints, TRAPS); 266 public: 267 klassItable(instanceKlassHandle klass); 268 269 itableOffsetEntry* offset_entry(int i) { assert(0 <= i && i <= _size_offset_table, "index out of bounds"); 270 return &((itableOffsetEntry*)vtable_start())[i]; } 271 272 itableMethodEntry* method_entry(int i) { assert(0 <= i && i <= _size_method_table, "index out of bounds"); 273 return &((itableMethodEntry*)method_start())[i]; } 274 275 int size_offset_table() { return _size_offset_table; } 276 277 // Initialization 278 void initialize_itable(bool checkconstraints, TRAPS); 279 280 // Updates 281 void initialize_with_method(Method* m); 282 283 #if INCLUDE_JVMTI 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(InstanceKlass* holder, bool * trace_name_printed); 291 bool check_no_old_or_obsolete_entries(); 292 void dump_itable(); 293 #endif // INCLUDE_JVMTI 294 295 // Setup of itable 296 static int assign_itable_indices_for_interface(Klass* klass); 297 static int method_count_for_interface(Klass* klass); 298 static int compute_itable_size(Array<Klass*>* transitive_interfaces); 299 static void setup_itable_offset_table(instanceKlassHandle klass); 300 301 // Resolving of method to index 302 static Method* method_for_itable_index(Klass* klass, int itable_index); 303 304 // Debugging/Statistics 305 static void print_statistics() PRODUCT_RETURN; 306 private: 307 intptr_t* vtable_start() const { return ((intptr_t*)_klass()) + _table_offset; } 308 intptr_t* method_start() const { return vtable_start() + _size_offset_table * itableOffsetEntry::size(); } 309 310 // Helper methods 311 static int calc_itable_size(int num_interfaces, int num_methods) { return (num_interfaces * itableOffsetEntry::size()) + (num_methods * itableMethodEntry::size()); } 312 313 // Statistics 314 NOT_PRODUCT(static int _total_classes;) // Total no. of classes with itables 315 NOT_PRODUCT(static long _total_size;) // Total no. of bytes used for itables 316 317 static void update_stats(int size) PRODUCT_RETURN NOT_PRODUCT({ _total_classes++; _total_size += size; }) 318 }; 319 320 #endif // SHARE_VM_OOPS_KLASSVTABLE_HPP