Implement in-place rehashing of HashTable.

src/objects.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 3448 matching lines @@
   // Maximal capacity of HashTable. Based on maximal length of underlying
   // FixedArray. Staying below kMaxCapacity also ensures that EntryToIndex
   // cannot overflow.
   static const int kMaxCapacity =
       (FixedArray::kMaxLength - kElementsStartOffset) / kEntrySize;
 
   // Find entry for key otherwise return kNotFound.
   inline int FindEntry(Key key);
   int FindEntry(Isolate* isolate, Key key);
 
+  void Rehash(Key key);

[Michael Starzinger, 2013/09/12 09:39:16]

nit: Let's add a short one-liner comment saying that this is an in-place
rehashing implementation, to contrast it with the existing Rehash() function.

+
  protected:
   // Find the entry at which to insert element with the given key that
   // has the given hash value.
   uint32_t FindInsertionEntry(uint32_t hash);
 
   // Returns the index for an entry (of the key)
   static inline int EntryToIndex(int entry) {
     return (entry * kEntrySize) + kElementsStartIndex;
   }
 
@@ skipping 26 matching lines @@
 
   inline static uint32_t FirstProbe(uint32_t hash, uint32_t size) {
     return hash & (size - 1);
   }
 
   inline static uint32_t NextProbe(
       uint32_t last, uint32_t number, uint32_t size) {
     return (last + number) & (size - 1);
   }
 
+  // Returns _expected_ if one of entries given by the first _probe_ probes is
+  // equal to  _expected_. Otherwise, returns the entry given by the probe
+  // number _probe_.
+  uint32_t EntryForProbe(Key key, Object* k, int probe, uint32_t expected);
+
+  void Swap(uint32_t entry1, uint32_t entry2, WriteBarrierMode mode);
+
   // Rehashes this hash-table into the new table.
   MUST_USE_RESULT MaybeObject* Rehash(HashTable* new_table, Key key);
 
   // Attempt to shrink hash table after removal of key.
   MUST_USE_RESULT MaybeObject* Shrink(Key key);
 
   // Ensure enough space for n additional elements.
   MUST_USE_RESULT MaybeObject* EnsureCapacity(int n, Key key);
 };
 
@@ skipping 6685 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_