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src/hotspot/share/classfile/compactHashtable.hpp

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  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_CLASSFILE_COMPACTHASHTABLE_HPP
  26 #define SHARE_VM_CLASSFILE_COMPACTHASHTABLE_HPP
  27 
  28 #include "oops/array.hpp"
  29 #include "oops/symbol.hpp"
  30 #include "utilities/hashtable.hpp"
  31 
  32 template <class T, class N> class CompactHashtable;







  33 class NumberSeq;
  34 class SimpleCompactHashtable;
  35 class SerializeClosure;
  36 
  37 // Stats for symbol tables in the CDS archive
  38 class CompactHashtableStats {
  39 public:
  40   int hashentry_count;
  41   int hashentry_bytes;
  42   int bucket_count;
  43   int bucket_bytes;
  44 };
  45 
  46 /////////////////////////////////////////////////////////////////////////
  47 //
  48 // The compact hash table writer. Used at dump time for writing out
  49 // the compact table to the shared archive.
  50 //
  51 // At dump time, the CompactHashtableWriter obtains all entries from the
  52 // symbol/string table and adds them to a new temporary hash table. The hash


  91     }
  92   }; // class CompactHashtableWriter::Entry
  93 
  94 private:
  95   int _num_entries;
  96   int _num_buckets;
  97   int _num_empty_buckets;
  98   int _num_value_only_buckets;
  99   int _num_other_buckets;
 100   GrowableArray<Entry>** _buckets;
 101   CompactHashtableStats* _stats;
 102   Array<u4>* _compact_buckets;
 103   Array<u4>* _compact_entries;
 104 
 105 public:
 106   // This is called at dump-time only
 107   CompactHashtableWriter(int num_buckets, CompactHashtableStats* stats);
 108   ~CompactHashtableWriter();
 109 
 110   void add(unsigned int hash, u4 value);
 111   void add(u4 value) {
 112     add((unsigned int)value, value);
 113   }
 114 
 115 private:
 116   void allocate_table();
 117   void dump_table(NumberSeq* summary);
 118 
 119 public:
 120   void dump(SimpleCompactHashtable *cht, const char* table_name);
 121   const char* table_name();
 122 };
 123 
 124 class CompactSymbolTableWriter: public CompactHashtableWriter {
 125 public:
 126   CompactSymbolTableWriter(int num_buckets, CompactHashtableStats* stats) :
 127     CompactHashtableWriter(num_buckets, stats) {}
 128   void add(unsigned int hash, Symbol *symbol);
 129   void dump(CompactHashtable<Symbol*, char> *cht);
 130 };
 131 
 132 class CompactStringTableWriter: public CompactHashtableWriter {
 133 public:
 134   CompactStringTableWriter(int num_entries, CompactHashtableStats* stats) :
 135     CompactHashtableWriter(num_entries, stats) {}
 136   void add(unsigned int hash, oop string);
 137   void dump(CompactHashtable<oop, char> *cht);
 138 };
 139 
 140 #define REGULAR_BUCKET_TYPE       0
 141 #define VALUE_ONLY_BUCKET_TYPE    1
 142 #define TABLEEND_BUCKET_TYPE      3
 143 #define BUCKET_OFFSET_MASK        0x3FFFFFFF
 144 #define BUCKET_OFFSET(info)       ((info) & BUCKET_OFFSET_MASK)
 145 #define BUCKET_TYPE_SHIFT         30
 146 #define BUCKET_TYPE(info)         (((info) & ~BUCKET_OFFSET_MASK) >> BUCKET_TYPE_SHIFT)
 147 #define BUCKET_INFO(offset, type) (((type) << BUCKET_TYPE_SHIFT) | ((offset) & BUCKET_OFFSET_MASK))
 148 
 149 /////////////////////////////////////////////////////////////////////////////
 150 //
 151 // CompactHashtable is used to stored the CDS archive's symbol/string table. Used
 152 // at runtime only to access the compact table from the archive.
 153 //
 154 // Because these tables are read-only (no entries can be added/deleted) at run-time
 155 // and tend to have large number of entries, we try to minimize the footprint
 156 // cost per entry.
 157 //
 158 // The CompactHashtable is split into two arrays
 159 //
 160 //   u4 buckets[num_buckets+1]; // bit[31,30]: type; bit[29-0]: offset
 161 //   u4 entries[<variable size>]
 162 //
 163 // The size of buckets[] is 'num_buckets + 1'. Each entry of
 164 // buckets[] is a 32-bit encoding of the bucket type and bucket offset,
 165 // with the type in the left-most 2-bit and offset in the remaining 30-bit.
 166 // The last entry is a special type. It contains the end of the last
 167 // bucket.
 168 //
 169 // There are two types of buckets, regular buckets and value_only buckets. The
 170 // value_only buckets have '01' in their highest 2-bit, and regular buckets have
 171 // '00' in their highest 2-bit.
 172 //


 208     _bucket_count = 0;
 209     _buckets = 0;
 210     _entries = 0;
 211   }
 212 
 213   void reset() {
 214     _bucket_count = 0;
 215     _entry_count = 0;
 216     _buckets = 0;
 217     _entries = 0;
 218   }
 219 
 220   void init(address base_address, u4 entry_count, u4 bucket_count, u4* buckets, u4* entries) {
 221     _base_address = base_address;
 222     _bucket_count = bucket_count;
 223     _entry_count = entry_count;
 224     _buckets = buckets;
 225     _entries = entries;
 226   }
 227 
 228   template <class I> inline void iterate(const I& iterator);
 229 
 230   bool exists(u4 value);
 231 
 232   // For reading from/writing to the CDS archive
 233   void serialize(SerializeClosure* soc);
 234 
 235   inline bool empty() {
 236     return (_entry_count == 0);
 237   }
 238 };
 239 
 240 template <class T, class N> class CompactHashtable : public SimpleCompactHashtable {






 241   friend class VMStructs;
 242 
 243 public:
 244   enum CompactHashtableType {
 245     _symbol_table = 0,
 246     _string_table = 1
 247   };
 248 
 249 private:
 250   u4 _type;
 251 
 252   inline Symbol* decode_entry(CompactHashtable<Symbol*, char>* const t,
 253                               u4 offset, const char* name, int len);
 254 
 255   inline oop decode_entry(CompactHashtable<oop, char>* const t,
 256                           u4 offset, const char* name, int len);
 257 public:
 258   CompactHashtable() : SimpleCompactHashtable() {}
 259 
 260   void set_type(CompactHashtableType type) {
 261     _type = (u4)type;






























 262   }
 263 
 264   // Lookup an entry from the compact table
 265   inline T lookup(const N* name, unsigned int hash, int len);
 266 
 267   // iterate over symbols
 268   void symbols_do(SymbolClosure *cl);
 269 
 270   // iterate over strings
 271   void oops_do(OopClosure* f);
 272 
 273   // For reading from/writing to the CDS archive
 274   void serialize(SerializeClosure* soc);
 275 
 276   uintx base_address() {
 277     return (uintx) _base_address;




 278   }
 279 };
 280 
 281 ////////////////////////////////////////////////////////////////////////
 282 //
 283 // Read/Write the contents of a hashtable textual dump (created by
 284 // SymbolTable::dump and StringTable::dump).
 285 // Because the dump file may be big (hundred of MB in extreme cases),
 286 // we use mmap for fast access when reading it.
 287 //
 288 class HashtableTextDump {
 289   int _fd;
 290   const char* _base;
 291   const char* _p;
 292   const char* _end;
 293   const char* _filename;
 294   size_t      _size;
 295   int         _prefix_type;
 296   int         _line_no;
 297 public:




  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_CLASSFILE_COMPACTHASHTABLE_HPP
  26 #define SHARE_VM_CLASSFILE_COMPACTHASHTABLE_HPP
  27 
  28 #include "oops/array.hpp"
  29 #include "oops/symbol.hpp"
  30 #include "utilities/hashtable.hpp"
  31 
  32 
  33 template <
  34   typename K,
  35   typename V,
  36   V (*DECODE)(address base_address, u4 offset),
  37   bool (*EQUALS)(V value, K key, int len)
  38   >
  39 class CompactHashtable;
  40 class NumberSeq;
  41 class SimpleCompactHashtable;
  42 class SerializeClosure;
  43 
  44 // Stats for symbol tables in the CDS archive
  45 class CompactHashtableStats {
  46 public:
  47   int hashentry_count;
  48   int hashentry_bytes;
  49   int bucket_count;
  50   int bucket_bytes;
  51 };
  52 
  53 /////////////////////////////////////////////////////////////////////////
  54 //
  55 // The compact hash table writer. Used at dump time for writing out
  56 // the compact table to the shared archive.
  57 //
  58 // At dump time, the CompactHashtableWriter obtains all entries from the
  59 // symbol/string table and adds them to a new temporary hash table. The hash


  98     }
  99   }; // class CompactHashtableWriter::Entry
 100 
 101 private:
 102   int _num_entries;
 103   int _num_buckets;
 104   int _num_empty_buckets;
 105   int _num_value_only_buckets;
 106   int _num_other_buckets;
 107   GrowableArray<Entry>** _buckets;
 108   CompactHashtableStats* _stats;
 109   Array<u4>* _compact_buckets;
 110   Array<u4>* _compact_entries;
 111 
 112 public:
 113   // This is called at dump-time only
 114   CompactHashtableWriter(int num_buckets, CompactHashtableStats* stats);
 115   ~CompactHashtableWriter();
 116 
 117   void add(unsigned int hash, u4 value);



 118 
 119 private:
 120   void allocate_table();
 121   void dump_table(NumberSeq* summary);
 122 
 123 public:
 124   void dump(SimpleCompactHashtable *cht, const char* table_name);

















 125 };
 126 
 127 #define REGULAR_BUCKET_TYPE       0
 128 #define VALUE_ONLY_BUCKET_TYPE    1
 129 #define TABLEEND_BUCKET_TYPE      3
 130 #define BUCKET_OFFSET_MASK        0x3FFFFFFF
 131 #define BUCKET_OFFSET(info)       ((info) & BUCKET_OFFSET_MASK)
 132 #define BUCKET_TYPE_SHIFT         30
 133 #define BUCKET_TYPE(info)         (((info) & ~BUCKET_OFFSET_MASK) >> BUCKET_TYPE_SHIFT)
 134 #define BUCKET_INFO(offset, type) (((type) << BUCKET_TYPE_SHIFT) | ((offset) & BUCKET_OFFSET_MASK))
 135 
 136 /////////////////////////////////////////////////////////////////////////////
 137 //
 138 // CompactHashtable is used to store the CDS archive's symbol/string tables.

 139 //
 140 // Because these tables are read-only (no entries can be added/deleted) at run-time
 141 // and tend to have large number of entries, we try to minimize the footprint
 142 // cost per entry.
 143 //
 144 // The CompactHashtable is split into two arrays
 145 //
 146 //   u4 buckets[num_buckets+1]; // bit[31,30]: type; bit[29-0]: offset
 147 //   u4 entries[<variable size>]
 148 //
 149 // The size of buckets[] is 'num_buckets + 1'. Each entry of
 150 // buckets[] is a 32-bit encoding of the bucket type and bucket offset,
 151 // with the type in the left-most 2-bit and offset in the remaining 30-bit.
 152 // The last entry is a special type. It contains the end of the last
 153 // bucket.
 154 //
 155 // There are two types of buckets, regular buckets and value_only buckets. The
 156 // value_only buckets have '01' in their highest 2-bit, and regular buckets have
 157 // '00' in their highest 2-bit.
 158 //


 194     _bucket_count = 0;
 195     _buckets = 0;
 196     _entries = 0;
 197   }
 198 
 199   void reset() {
 200     _bucket_count = 0;
 201     _entry_count = 0;
 202     _buckets = 0;
 203     _entries = 0;
 204   }
 205 
 206   void init(address base_address, u4 entry_count, u4 bucket_count, u4* buckets, u4* entries) {
 207     _base_address = base_address;
 208     _bucket_count = bucket_count;
 209     _entry_count = entry_count;
 210     _buckets = buckets;
 211     _entries = entries;
 212   }
 213 




 214   // For reading from/writing to the CDS archive
 215   void serialize(SerializeClosure* soc);
 216 
 217   inline bool empty() {
 218     return (_entry_count == 0);
 219   }
 220 };
 221 
 222 template <
 223   typename K,
 224   typename V,
 225   V (*DECODE)(address base_address, u4 offset),
 226   bool (*EQUALS)(V value, K key, int len)
 227   >
 228 class CompactHashtable : public SimpleCompactHashtable {
 229   friend class VMStructs;
 230 
 231   V decode(u4 offset) const {
 232     return DECODE(_base_address, offset);
 233   }








 234 


 235 public:
 236   CompactHashtable() : SimpleCompactHashtable() {}
 237 
 238   // Lookup a value V from the compact table using key K
 239   inline V lookup(K key, unsigned int hash, int len) const {
 240     if (_entry_count > 0) {
 241       int index = hash % _bucket_count;
 242       u4 bucket_info = _buckets[index];
 243       u4 bucket_offset = BUCKET_OFFSET(bucket_info);
 244       int bucket_type = BUCKET_TYPE(bucket_info);
 245       u4* entry = _entries + bucket_offset;
 246 
 247       if (bucket_type == VALUE_ONLY_BUCKET_TYPE) {
 248         V value = decode(entry[0]);
 249         if (EQUALS(value, key, len)) {
 250           return value;
 251         }
 252       } else {
 253         // This is a regular bucket, which has more than one
 254         // entries. Each entry is a pair of entry (hash, offset).
 255         // Seek until the end of the bucket.
 256         u4* entry_max = _entries + BUCKET_OFFSET(_buckets[index + 1]);
 257         while (entry < entry_max) {
 258           unsigned int h = (unsigned int)(entry[0]);
 259           if (h == hash) {
 260             V value = decode(entry[1]);
 261             if (EQUALS(value, key, len)) {
 262               return value;
 263             }
 264           }
 265           entry += 2;
 266         }
 267       }
 268     }
 269     return NULL;
 270   }
 271 
 272   template <class ITER>
 273   inline void iterate(ITER* iter) const {
 274     for (u4 i = 0; i < _bucket_count; i++) {
 275       u4 bucket_info = _buckets[i];
 276       u4 bucket_offset = BUCKET_OFFSET(bucket_info);
 277       int bucket_type = BUCKET_TYPE(bucket_info);
 278       u4* entry = _entries + bucket_offset;
 279 
 280       if (bucket_type == VALUE_ONLY_BUCKET_TYPE) {
 281         iter->do_value(decode(entry[0]));
 282       } else {
 283         u4*entry_max = _entries + BUCKET_OFFSET(_buckets[i + 1]);
 284         while (entry < entry_max) {
 285           iter->do_value(decode(entry[1]));
 286           entry += 2;
 287         }
 288       }
 289     }
 290   }
 291 };
 292 
 293 ////////////////////////////////////////////////////////////////////////
 294 //
 295 // Read/Write the contents of a hashtable textual dump (created by
 296 // SymbolTable::dump and StringTable::dump).
 297 // Because the dump file may be big (hundred of MB in extreme cases),
 298 // we use mmap for fast access when reading it.
 299 //
 300 class HashtableTextDump {
 301   int _fd;
 302   const char* _base;
 303   const char* _p;
 304   const char* _end;
 305   const char* _filename;
 306   size_t      _size;
 307   int         _prefix_type;
 308   int         _line_no;
 309 public:


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