Changed hash table to use more of the hash value when probing.

src/objects.h

 // Copyright 2006-2009 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 2033 matching lines @@
     return !k->IsNull() && !k->IsUndefined();
   }
 
   // Garbage collection support.
   void IteratePrefix(ObjectVisitor* visitor);
   void IterateElements(ObjectVisitor* visitor);
 
   // Casting.
   static inline HashTable* cast(Object* obj);
 
-  // Compute the probe offset (quadratic probing).
-  INLINE(static uint32_t GetProbeOffset(uint32_t n)) {
-    return (n + n * n) >> 1;
-  }
-
   static const int kNumberOfElementsIndex = 0;
   static const int kCapacityIndex         = 1;
   static const int kPrefixStartIndex      = 2;
   static const int kElementsStartIndex    =
       kPrefixStartIndex + Shape::kPrefixSize;
   static const int kEntrySize             = Shape::kEntrySize;
   static const int kElementsStartOffset   =
       kHeaderSize + kElementsStartIndex * kPointerSize;
 
   // Constant used for denoting a absent entry.
   static const int kNotFound = -1;
 
   // Find entry for key otherwise return -1.
   int FindEntry(Key key);
 
+  static const uint32_t kNofFastProbes = 4;
+  static const uint32_t kHashRotateShift = 3;
+
  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;
   }
 
   // Update the number of elements in the dictionary.
   void SetNumberOfElements(int nof) {
     fast_set(this, kNumberOfElementsIndex, Smi::FromInt(nof));
   }
 
   // Sets the capacity of the hash table.
   void SetCapacity(int capacity) {
     // To scale a computed hash code to fit within the hash table, we
     // use bit-wise AND with a mask, so the capacity must be positive
     // and non-zero.
     ASSERT(capacity > 0);
     fast_set(this, kCapacityIndex, Smi::FromInt(capacity));
   }
 
-
-  // Returns probe entry.
-  static uint32_t GetProbe(uint32_t hash, uint32_t number, uint32_t size) {
-    ASSERT(IsPowerOf2(size));
-    return (hash + GetProbeOffset(number)) & (size - 1);
-  }
-
   // Ensure enough space for n additional elements.
   Object* EnsureCapacity(int n, Key key);
 };
 
 
 
 // HashTableKey is an abstract superclass for virtual key behavior.
 class HashTableKey {
  public:
   // Returns whether the other object matches this key.
@@ skipping 2623 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_