klassVtable.hpp revision 3602:da91efe96a93
1/* 2 * Copyright (c) 1997, 2012, 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 42class vtableEntry; 43 44class 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, int &num_miranda_methods, 88 Klass* super, Array<Method*>* methods, 89 AccessFlags class_flags, Handle classloader, 90 Symbol* classname, Array<Klass*>* 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(Method** old_methods, Method** new_methods, 100 int methods_length, bool * trace_name_printed); 101 102 // Debugging code 103 void print() PRODUCT_RETURN; 104 void verify(outputStream* st, bool force = false); 105 static void print_statistics() PRODUCT_RETURN; 106 107#ifndef PRODUCT 108 bool check_no_old_entries(); 109 void dump_vtable(); 110#endif 111 112 protected: 113 friend class vtableEntry; 114 private: 115 enum { VTABLE_TRANSITIVE_OVERRIDE_VERSION = 51 } ; 116 void copy_vtable_to(vtableEntry* start); 117 int initialize_from_super(KlassHandle super); 118 int index_of(Method* m, int len) const; // same as index_of, but search only up to len 119 void put_method_at(Method* m, int index); 120 static bool needs_new_vtable_entry(methodHandle m, Klass* super, Handle classloader, Symbol* classname, AccessFlags access_flags, TRAPS); 121 122 bool update_inherited_vtable(InstanceKlass* klass, methodHandle target_method, int super_vtable_len, bool checkconstraints, TRAPS); 123 InstanceKlass* find_transitive_override(InstanceKlass* initialsuper, methodHandle target_method, int vtable_index, 124 Handle target_loader, Symbol* target_classname, Thread* THREAD); 125 126 // support for miranda methods 127 bool is_miranda_entry_at(int i); 128 void fill_in_mirandas(int& initialized); 129 static bool is_miranda(Method* m, Array<Method*>* class_methods, Klass* super); 130 static void add_new_mirandas_to_list(GrowableArray<Method*>* list_of_current_mirandas, Array<Method*>* current_interface_methods, Array<Method*>* class_methods, Klass* super); 131 static void get_mirandas(GrowableArray<Method*>* mirandas, Klass* super, Array<Method*>* class_methods, Array<Klass*>* local_interfaces); 132 static int get_num_mirandas(Klass* super, Array<Method*>* class_methods, Array<Klass*>* local_interfaces); 133 134 135 void verify_against(outputStream* st, klassVtable* vt, int index); 136 inline InstanceKlass* ik() const; 137}; 138 139 140// private helper class for klassVtable 141// description of entry points: 142// destination is interpreted: 143// from_compiled_code_entry_point -> c2iadapter 144// from_interpreter_entry_point -> interpreter entry point 145// destination is compiled: 146// from_compiled_code_entry_point -> nmethod entry point 147// from_interpreter_entry_point -> i2cadapter 148class vtableEntry VALUE_OBJ_CLASS_SPEC { 149 public: 150 // size in words 151 static int size() { 152 return sizeof(vtableEntry) / sizeof(HeapWord); 153 } 154 static int method_offset_in_bytes() { return offset_of(vtableEntry, _method); } 155 Method* method() const { return _method; } 156 157 private: 158 Method* _method; 159 void set(Method* method) { assert(method != NULL, "use clear"); _method = method; } 160 void clear() { _method = NULL; } 161 void print() PRODUCT_RETURN; 162 void verify(klassVtable* vt, outputStream* st); 163 164 friend class klassVtable; 165}; 166 167 168inline Method* klassVtable::method_at(int i) const { 169 assert(i >= 0 && i < _length, "index out of bounds"); 170 assert(table()[i].method() != NULL, "should not be null"); 171 assert(((Metadata*)table()[i].method())->is_method(), "should be method"); 172 return table()[i].method(); 173} 174 175inline Method* klassVtable::unchecked_method_at(int i) const { 176 assert(i >= 0 && i < _length, "index out of bounds"); 177 return table()[i].method(); 178} 179 180inline Method** klassVtable::adr_method_at(int i) const { 181 // Allow one past the last entry to be referenced; useful for loop bounds. 182 assert(i >= 0 && i <= _length, "index out of bounds"); 183 return (Method**)(address(table() + i) + vtableEntry::method_offset_in_bytes()); 184} 185 186// -------------------------------------------------------------------------------- 187class klassItable; 188class itableMethodEntry; 189 190class itableOffsetEntry VALUE_OBJ_CLASS_SPEC { 191 private: 192 Klass* _interface; 193 int _offset; 194 public: 195 Klass* interface_klass() const { return _interface; } 196 int offset() const { return _offset; } 197 198 static itableMethodEntry* method_entry(Klass* k, int offset) { return (itableMethodEntry*)(((address)k) + offset); } 199 itableMethodEntry* first_method_entry(Klass* k) { return method_entry(k, _offset); } 200 201 void initialize(Klass* interf, int offset) { _interface = interf; _offset = offset; } 202 203 // Static size and offset accessors 204 static int size() { return sizeof(itableOffsetEntry) / HeapWordSize; } // size in words 205 static int interface_offset_in_bytes() { return offset_of(itableOffsetEntry, _interface); } 206 static int offset_offset_in_bytes() { return offset_of(itableOffsetEntry, _offset); } 207 208 friend class klassItable; 209}; 210 211 212class itableMethodEntry VALUE_OBJ_CLASS_SPEC { 213 private: 214 Method* _method; 215 216 public: 217 Method* method() const { return _method; } 218 219 void clear() { _method = NULL; } 220 221 void initialize(Method* method); 222 223 // Static size and offset accessors 224 static int size() { return sizeof(itableMethodEntry) / HeapWordSize; } // size in words 225 static int method_offset_in_bytes() { return offset_of(itableMethodEntry, _method); } 226 227 friend class klassItable; 228}; 229 230// 231// Format of an itable 232// 233// ---- offset table --- 234// Klass* of interface 1 \ 235// offset to vtable from start of oop / offset table entry 236// ... 237// Klass* of interface n \ 238// offset to vtable from start of oop / offset table entry 239// --- vtable for interface 1 --- 240// Method* \ 241// compiler entry point / method table entry 242// ... 243// Method* \ 244// compiler entry point / method table entry 245// -- vtable for interface 2 --- 246// ... 247// 248class klassItable : public ResourceObj { 249 private: 250 instanceKlassHandle _klass; // my klass 251 int _table_offset; // offset of start of itable data within klass (in words) 252 int _size_offset_table; // size of offset table (in itableOffset entries) 253 int _size_method_table; // size of methodtable (in itableMethodEntry entries) 254 255 void initialize_itable_for_interface(int method_table_offset, KlassHandle interf_h, bool checkconstraints, TRAPS); 256 public: 257 klassItable(instanceKlassHandle klass); 258 259 itableOffsetEntry* offset_entry(int i) { assert(0 <= i && i <= _size_offset_table, "index out of bounds"); 260 return &((itableOffsetEntry*)vtable_start())[i]; } 261 262 itableMethodEntry* method_entry(int i) { assert(0 <= i && i <= _size_method_table, "index out of bounds"); 263 return &((itableMethodEntry*)method_start())[i]; } 264 265 int size_offset_table() { return _size_offset_table; } 266 267 // Initialization 268 void initialize_itable(bool checkconstraints, TRAPS); 269 270 // Updates 271 void initialize_with_method(Method* m); 272 273 // RedefineClasses() API support: 274 // if any entry of this itable points to any of old_methods, 275 // replace it with the corresponding new_method. 276 // trace_name_printed is set to true if the current call has 277 // printed the klass name so that other routines in the adjust_* 278 // group don't print the klass name. 279 void adjust_method_entries(Method** old_methods, Method** new_methods, 280 int methods_length, bool * trace_name_printed); 281 282 // Setup of itable 283 static int compute_itable_size(Array<Klass*>* transitive_interfaces); 284 static void setup_itable_offset_table(instanceKlassHandle klass); 285 286 // Resolving of method to index 287 static int compute_itable_index(Method* m); 288 // ...and back again: 289 static Method* method_for_itable_index(Klass* klass, int itable_index); 290 291 // Debugging/Statistics 292 static void print_statistics() PRODUCT_RETURN; 293 private: 294 intptr_t* vtable_start() const { return ((intptr_t*)_klass()) + _table_offset; } 295 intptr_t* method_start() const { return vtable_start() + _size_offset_table * itableOffsetEntry::size(); } 296 297 // Helper methods 298 static int calc_itable_size(int num_interfaces, int num_methods) { return (num_interfaces * itableOffsetEntry::size()) + (num_methods * itableMethodEntry::size()); } 299 300 // Statistics 301 NOT_PRODUCT(static int _total_classes;) // Total no. of classes with itables 302 NOT_PRODUCT(static long _total_size;) // Total no. of bytes used for itables 303 304 static void update_stats(int size) PRODUCT_RETURN NOT_PRODUCT({ _total_classes++; _total_size += size; }) 305 306 public: 307#ifndef PRODUCT 308 bool check_no_old_entries(); 309#endif 310}; 311 312#endif // SHARE_VM_OOPS_KLASSVTABLE_HPP 313