1 /*
   2  * Copyright (c) 1997, 2011, 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 
 102   // Garbage collection
 103   void oop_follow_contents();
 104   void oop_adjust_pointers();
 105 
 106 #ifndef SERIALGC
 107   // Parallel Old
 108   void oop_follow_contents(ParCompactionManager* cm);
 109   void oop_update_pointers(ParCompactionManager* cm);
 110 #endif // SERIALGC
 111 
 112   // Iterators
 113   void oop_oop_iterate(OopClosure* blk);
 114   void oop_oop_iterate_m(OopClosure* blk, MemRegion mr);
 115 
 116   // Debugging code
 117   void print()                                              PRODUCT_RETURN;
 118   void verify(outputStream* st, bool force = false);
 119   static void print_statistics()                            PRODUCT_RETURN;
 120 
 121 #ifndef PRODUCT
 122   bool check_no_old_entries();
 123   void dump_vtable();
 124 #endif
 125 
 126  protected:
 127   friend class vtableEntry;
 128  private:
 129   enum { VTABLE_TRANSITIVE_OVERRIDE_VERSION = 51 } ;
 130   void copy_vtable_to(vtableEntry* start);
 131   int  initialize_from_super(KlassHandle super);
 132   int  index_of(methodOop m, int len) const; // same as index_of, but search only up to len
 133   void put_method_at(methodOop m, int index);
 134   static bool needs_new_vtable_entry(methodHandle m, klassOop super, Handle classloader, Symbol* classname, AccessFlags access_flags, TRAPS);
 135 
 136   bool update_inherited_vtable(instanceKlass* klass, methodHandle target_method, int super_vtable_len, bool checkconstraints, TRAPS);
 137  instanceKlass* find_transitive_override(instanceKlass* initialsuper, methodHandle target_method, int vtable_index,
 138                                          Handle target_loader, Symbol* target_classname, Thread* THREAD);
 139 
 140   // support for miranda methods
 141   bool is_miranda_entry_at(int i);
 142   void fill_in_mirandas(int& initialized);
 143   static bool is_miranda(methodOop m, objArrayOop class_methods, klassOop super);
 144   static void add_new_mirandas_to_list(GrowableArray<methodOop>* list_of_current_mirandas, objArrayOop current_interface_methods, objArrayOop class_methods, klassOop super);
 145   static void get_mirandas(GrowableArray<methodOop>* mirandas, klassOop super, objArrayOop class_methods, objArrayOop local_interfaces);
 146   static int get_num_mirandas(klassOop super, objArrayOop class_methods, objArrayOop local_interfaces);
 147 
 148 
 149   void verify_against(outputStream* st, klassVtable* vt, int index);
 150   inline instanceKlass* ik() const;
 151 };
 152 
 153 
 154 // private helper class for klassVtable
 155 // description of entry points:
 156 //    destination is interpreted:
 157 //      from_compiled_code_entry_point -> c2iadapter
 158 //      from_interpreter_entry_point   -> interpreter entry point
 159 //    destination is compiled:
 160 //      from_compiled_code_entry_point -> nmethod entry point
 161 //      from_interpreter_entry_point   -> i2cadapter
 162 class vtableEntry VALUE_OBJ_CLASS_SPEC {
 163  public:
 164   // size in words
 165   static int size() {
 166     return sizeof(vtableEntry) / sizeof(HeapWord);
 167   }
 168   static int method_offset_in_bytes() { return offset_of(vtableEntry, _method); }
 169   methodOop method() const    { return _method; }
 170 
 171  private:
 172   methodOop _method;
 173   void set(methodOop method)  { assert(method != NULL, "use clear"); _method = method; }
 174   void clear()                { _method = NULL; }
 175   void print()                                        PRODUCT_RETURN;
 176   void verify(klassVtable* vt, outputStream* st);
 177 
 178   friend class klassVtable;
 179 };
 180 
 181 
 182 inline methodOop klassVtable::method_at(int i) const {
 183   assert(i >= 0 && i < _length, "index out of bounds");
 184   assert(table()[i].method() != NULL, "should not be null");
 185   assert(oop(table()[i].method())->is_method(), "should be method");
 186   return table()[i].method();
 187 }
 188 
 189 inline methodOop klassVtable::unchecked_method_at(int i) const {
 190   assert(i >= 0 && i < _length, "index out of bounds");
 191   return table()[i].method();
 192 }
 193 
 194 inline oop* klassVtable::adr_method_at(int i) const {
 195   // Allow one past the last entry to be referenced; useful for loop bounds.
 196   assert(i >= 0 && i <= _length, "index out of bounds");
 197   return (oop*)(address(table() + i) + vtableEntry::method_offset_in_bytes());
 198 }
 199 
 200 // --------------------------------------------------------------------------------
 201 class klassItable;
 202 class itableMethodEntry;
 203 
 204 class itableOffsetEntry VALUE_OBJ_CLASS_SPEC {
 205  private:
 206   klassOop _interface;
 207   int      _offset;
 208  public:
 209   klassOop interface_klass() const { return _interface; }
 210   int      offset() const          { return _offset; }
 211 
 212   static itableMethodEntry* method_entry(klassOop k, int offset) { return (itableMethodEntry*)(((address)k) + offset); }
 213   itableMethodEntry* first_method_entry(klassOop k)              { return method_entry(k, _offset); }
 214 
 215   void initialize(klassOop interf, int offset) { _interface = interf; _offset = offset; }
 216 
 217   // Static size and offset accessors
 218   static int size()                       { return sizeof(itableOffsetEntry) / HeapWordSize; }    // size in words
 219   static int interface_offset_in_bytes()  { return offset_of(itableOffsetEntry, _interface); }
 220   static int offset_offset_in_bytes()     { return offset_of(itableOffsetEntry, _offset); }
 221 
 222   friend class klassItable;
 223 };
 224 
 225 
 226 class itableMethodEntry VALUE_OBJ_CLASS_SPEC {
 227  private:
 228   methodOop _method;
 229 
 230  public:
 231   methodOop method() const { return _method; }
 232 
 233   void clear()             { _method = NULL; }
 234 
 235   void initialize(methodOop method);
 236 
 237   // Static size and offset accessors
 238   static int size()                         { return sizeof(itableMethodEntry) / HeapWordSize; }  // size in words
 239   static int method_offset_in_bytes()       { return offset_of(itableMethodEntry, _method); }
 240 
 241   friend class klassItable;
 242 };
 243 
 244 //
 245 // Format of an itable
 246 //
 247 //    ---- offset table ---
 248 //    klassOop of interface 1             \
 249 //    offset to vtable from start of oop  / offset table entry
 250 //    ...
 251 //    klassOop of interface n             \
 252 //    offset to vtable from start of oop  / offset table entry
 253 //    --- vtable for interface 1 ---
 254 //    methodOop                           \
 255 //    compiler entry point                / method table entry
 256 //    ...
 257 //    methodOop                           \
 258 //    compiler entry point                / method table entry
 259 //    -- vtable for interface 2 ---
 260 //    ...
 261 //
 262 class klassItable : public ResourceObj {
 263  private:
 264   instanceKlassHandle  _klass;             // my klass
 265   int                  _table_offset;      // offset of start of itable data within klass (in words)
 266   int                  _size_offset_table; // size of offset table (in itableOffset entries)
 267   int                  _size_method_table; // size of methodtable (in itableMethodEntry entries)
 268 
 269   void initialize_itable_for_interface(int method_table_offset, KlassHandle interf_h, bool checkconstraints, TRAPS);
 270  public:
 271   klassItable(instanceKlassHandle klass);
 272 
 273   itableOffsetEntry* offset_entry(int i) { assert(0 <= i && i <= _size_offset_table, "index out of bounds");
 274                                            return &((itableOffsetEntry*)vtable_start())[i]; }
 275 
 276   itableMethodEntry* method_entry(int i) { assert(0 <= i && i <= _size_method_table, "index out of bounds");
 277                                            return &((itableMethodEntry*)method_start())[i]; }
 278 
 279   int size_offset_table()                { return _size_offset_table; }
 280 
 281   // Initialization
 282   void initialize_itable(bool checkconstraints, TRAPS);
 283 
 284   // Updates
 285   void initialize_with_method(methodOop m);
 286 
 287   // RedefineClasses() API support:
 288   // if any entry of this itable points to any of old_methods,
 289   // replace it with the corresponding new_method.
 290   // trace_name_printed is set to true if the current call has
 291   // printed the klass name so that other routines in the adjust_*
 292   // group don't print the klass name.
 293   void adjust_method_entries(methodOop* old_methods, methodOop* new_methods,
 294                              int methods_length, bool * trace_name_printed);


 295 
 296   // Garbage collection
 297   void oop_follow_contents();
 298   void oop_adjust_pointers();
 299 
 300 #ifndef SERIALGC
 301   // Parallel Old
 302   void oop_follow_contents(ParCompactionManager* cm);
 303   void oop_update_pointers(ParCompactionManager* cm);
 304 #endif // SERIALGC
 305 
 306   // Iterators
 307   void oop_oop_iterate(OopClosure* blk);
 308   void oop_oop_iterate_m(OopClosure* blk, MemRegion mr);
 309 
 310   // Setup of itable
 311   static int compute_itable_size(objArrayHandle transitive_interfaces);
 312   static void setup_itable_offset_table(instanceKlassHandle klass);
 313 
 314   // Resolving of method to index
 315   static int compute_itable_index(methodOop m);
 316   // ...and back again:
 317   static methodOop method_for_itable_index(klassOop klass, int itable_index);
 318 
 319   // Debugging/Statistics
 320   static void print_statistics() PRODUCT_RETURN;
 321  private:
 322   intptr_t* vtable_start() const { return ((intptr_t*)_klass()) + _table_offset; }
 323   intptr_t* method_start() const { return vtable_start() + _size_offset_table * itableOffsetEntry::size(); }
 324 
 325   // Helper methods
 326   static int  calc_itable_size(int num_interfaces, int num_methods) { return (num_interfaces * itableOffsetEntry::size()) + (num_methods * itableMethodEntry::size()); }
 327 
 328   // Statistics
 329   NOT_PRODUCT(static int  _total_classes;)   // Total no. of classes with itables
 330   NOT_PRODUCT(static long _total_size;)      // Total no. of bytes used for itables
 331 
 332   static void update_stats(int size) PRODUCT_RETURN NOT_PRODUCT({ _total_classes++; _total_size += size; })
 333 };
 334 
 335 #endif // SHARE_VM_OOPS_KLASSVTABLE_HPP
--- EOF ---