src/share/vm/utilities/hashtable.hpp

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rev 6680 : 8056084: Refactor Hashtable to allow implementations without rehashing support
Reviewed-by: gziemski, jmasa, brutisso, coleenp, tschatzl


 161   void reverse();
 162 
 163 private:
 164   // Instance variables
 165   int               _table_size;
 166   HashtableBucket<F>*     _buckets;
 167   BasicHashtableEntry<F>* _free_list;
 168   char*             _first_free_entry;
 169   char*             _end_block;
 170   int               _entry_size;
 171   int               _number_of_entries;
 172 
 173 protected:
 174 
 175 #ifdef ASSERT
 176   int               _lookup_count;
 177   int               _lookup_length;
 178   void verify_lookup_length(double load);
 179 #endif
 180 
 181   enum {
 182     rehash_count = 100,
 183     rehash_multiple = 60
 184   };
 185 
 186   void initialize(int table_size, int entry_size, int number_of_entries);
 187 
 188   // Accessor
 189   int entry_size() const { return _entry_size; }
 190 
 191   // The following method is MT-safe and may be used with caution.
 192   BasicHashtableEntry<F>* bucket(int i);
 193 
 194   // The following method is not MT-safe and must be done under lock.
 195   BasicHashtableEntry<F>** bucket_addr(int i) { return _buckets[i].entry_addr(); }
 196 



 197   // Table entry management
 198   BasicHashtableEntry<F>* new_entry(unsigned int hashValue);
 199 
 200   // Check that the table is unbalanced
 201   bool check_rehash_table(int count);
 202 
 203   // Used when moving the entry to another table
 204   // Clean up links, but do not add to free_list
 205   void unlink_entry(BasicHashtableEntry<F>* entry) {
 206     entry->set_next(NULL);
 207     --_number_of_entries;
 208   }
 209 
 210   // Move over freelist and free block for allocation
 211   void copy_freelist(BasicHashtable* src) {
 212     _free_list = src->_free_list;
 213     src->_free_list = NULL;
 214     _first_free_entry = src->_first_free_entry;
 215     src->_first_free_entry = NULL;
 216     _end_block = src->_end_block;
 217     src->_end_block = NULL;
 218   }
 219 
 220   // Free the buckets in this hashtable
 221   void free_buckets();
 222 


 260     return (unsigned int) name->identity_hash();
 261   }
 262 
 263   int index_for(Symbol* name) {
 264     return this->hash_to_index(compute_hash(name));
 265   }
 266 
 267   // Table entry management
 268   HashtableEntry<T, F>* new_entry(unsigned int hashValue, T obj);
 269 
 270   // The following method is MT-safe and may be used with caution.
 271   HashtableEntry<T, F>* bucket(int i) {
 272     return (HashtableEntry<T, F>*)BasicHashtable<F>::bucket(i);
 273   }
 274 
 275   // The following method is not MT-safe and must be done under lock.
 276   HashtableEntry<T, F>** bucket_addr(int i) {
 277     return (HashtableEntry<T, F>**)BasicHashtable<F>::bucket_addr(i);
 278   }
 279 






















 280   // Function to move these elements into the new table.
 281   void move_to(Hashtable<T, F>* new_table);
 282   static bool use_alternate_hashcode()  { return _seed != 0; }
 283   static juint seed()                    { return _seed; }
 284 
 285   static int literal_size(Symbol *symbol);
 286   static int literal_size(oop oop);
 287 
 288   // The following two are currently not used, but are needed anyway because some
 289   // C++ compilers (MacOS and Solaris) force the instantiation of
 290   // Hashtable<ConstantPool*, mtClass>::dump_table() even though we never call this function
 291   // in the VM code.
 292   static int literal_size(ConstantPool *cp) {Unimplemented(); return 0;}
 293   static int literal_size(Klass *k)         {Unimplemented(); return 0;}
 294 
 295 public:
 296   void dump_table(outputStream* st, const char *table_name);
 297 
 298  private:
 299   static juint _seed;
 300 };
 301 
 302 
 303 //  Verions of hashtable where two handles are used to compute the index.
 304 
 305 template <class T, MEMFLAGS F> class TwoOopHashtable : public Hashtable<T, F> {
 306   friend class VMStructs;
 307 protected:
 308   TwoOopHashtable(int table_size, int entry_size)
 309     : Hashtable<T, F>(table_size, entry_size) {}
 310 
 311   TwoOopHashtable(int table_size, int entry_size, HashtableBucket<F>* t,
 312                   int number_of_entries)
 313     : Hashtable<T, F>(table_size, entry_size, t, number_of_entries) {}
 314 
 315 public:


 161   void reverse();
 162 
 163 private:
 164   // Instance variables
 165   int               _table_size;
 166   HashtableBucket<F>*     _buckets;
 167   BasicHashtableEntry<F>* _free_list;
 168   char*             _first_free_entry;
 169   char*             _end_block;
 170   int               _entry_size;
 171   int               _number_of_entries;
 172 
 173 protected:
 174 
 175 #ifdef ASSERT
 176   int               _lookup_count;
 177   int               _lookup_length;
 178   void verify_lookup_length(double load);
 179 #endif
 180 





 181   void initialize(int table_size, int entry_size, int number_of_entries);
 182 
 183   // Accessor
 184   int entry_size() const { return _entry_size; }
 185 
 186   // The following method is MT-safe and may be used with caution.
 187   BasicHashtableEntry<F>* bucket(int i);
 188 
 189   // The following method is not MT-safe and must be done under lock.
 190   BasicHashtableEntry<F>** bucket_addr(int i) { return _buckets[i].entry_addr(); }
 191 
 192   // Attempt to get an entry from the free list
 193   BasicHashtableEntry<F>* new_entry_free_list();
 194 
 195   // Table entry management
 196   BasicHashtableEntry<F>* new_entry(unsigned int hashValue);
 197 



 198   // Used when moving the entry to another table
 199   // Clean up links, but do not add to free_list
 200   void unlink_entry(BasicHashtableEntry<F>* entry) {
 201     entry->set_next(NULL);
 202     --_number_of_entries;
 203   }
 204 
 205   // Move over freelist and free block for allocation
 206   void copy_freelist(BasicHashtable* src) {
 207     _free_list = src->_free_list;
 208     src->_free_list = NULL;
 209     _first_free_entry = src->_first_free_entry;
 210     src->_first_free_entry = NULL;
 211     _end_block = src->_end_block;
 212     src->_end_block = NULL;
 213   }
 214 
 215   // Free the buckets in this hashtable
 216   void free_buckets();
 217 


 255     return (unsigned int) name->identity_hash();
 256   }
 257 
 258   int index_for(Symbol* name) {
 259     return this->hash_to_index(compute_hash(name));
 260   }
 261 
 262   // Table entry management
 263   HashtableEntry<T, F>* new_entry(unsigned int hashValue, T obj);
 264 
 265   // The following method is MT-safe and may be used with caution.
 266   HashtableEntry<T, F>* bucket(int i) {
 267     return (HashtableEntry<T, F>*)BasicHashtable<F>::bucket(i);
 268   }
 269 
 270   // The following method is not MT-safe and must be done under lock.
 271   HashtableEntry<T, F>** bucket_addr(int i) {
 272     return (HashtableEntry<T, F>**)BasicHashtable<F>::bucket_addr(i);
 273   }
 274 
 275 };
 276 
 277 template <class T, MEMFLAGS F> class RehashableHashtable : public Hashtable<T, F> {
 278  protected:
 279 
 280   enum {
 281     rehash_count = 100,
 282     rehash_multiple = 60
 283   };
 284 
 285   // Check that the table is unbalanced
 286   bool check_rehash_table(int count);
 287 
 288  public:
 289   RehashableHashtable(int table_size, int entry_size)
 290     : Hashtable<T, F>(table_size, entry_size) { }
 291 
 292   RehashableHashtable(int table_size, int entry_size,
 293                    HashtableBucket<F>* buckets, int number_of_entries)
 294     : Hashtable<T, F>(table_size, entry_size, buckets, number_of_entries) { }
 295 
 296 
 297   // Function to move these elements into the new table.
 298   void move_to(RehashableHashtable<T, F>* new_table);
 299   static bool use_alternate_hashcode()  { return _seed != 0; }
 300   static juint seed()                    { return _seed; }
 301 
 302   static int literal_size(Symbol *symbol);
 303   static int literal_size(oop oop);
 304 
 305   // The following two are currently not used, but are needed anyway because some
 306   // C++ compilers (MacOS and Solaris) force the instantiation of
 307   // Hashtable<ConstantPool*, mtClass>::dump_table() even though we never call this function
 308   // in the VM code.
 309   static int literal_size(ConstantPool *cp) {Unimplemented(); return 0;}
 310   static int literal_size(Klass *k)         {Unimplemented(); return 0;}
 311 

 312   void dump_table(outputStream* st, const char *table_name);
 313 
 314  private:
 315   static juint _seed;
 316 };
 317 
 318 
 319 //  Verions of hashtable where two handles are used to compute the index.
 320 
 321 template <class T, MEMFLAGS F> class TwoOopHashtable : public Hashtable<T, F> {
 322   friend class VMStructs;
 323 protected:
 324   TwoOopHashtable(int table_size, int entry_size)
 325     : Hashtable<T, F>(table_size, entry_size) {}
 326 
 327   TwoOopHashtable(int table_size, int entry_size, HashtableBucket<F>* t,
 328                   int number_of_entries)
 329     : Hashtable<T, F>(table_size, entry_size, t, number_of_entries) {}
 330 
 331 public: