Reintroduced dictionary that can use objects as keys.

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 13edfd78ba7bc46f569600fb2b2c7d8a841734cf..9cb7250819ee69ad34ba920012c64234209be652 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -1638,6 +1638,11 @@ class JSObject: public JSReceiver {
   MUST_USE_RESULT inline MaybeObject* SetHiddenPropertiesObject(
       Object* hidden_obj);
 
+  MUST_USE_RESULT MaybeObject* GetHiddenProperties(bool create_if_needed);

[Vitaly Repeshko, 2011/07/26 13:53:14]

Document what is returned when there are no existing hidden properties and
create_if_needed is false.

[Michael Starzinger, 2011/07/26 22:30:23]

Fixed.

+
+  // Retrieves a permanent object identity hash code.
+  MUST_USE_RESULT MaybeObject* GetIdentityHash();
+
   MUST_USE_RESULT MaybeObject* DeleteProperty(String* name, DeleteMode mode);
   MUST_USE_RESULT MaybeObject* DeleteElement(uint32_t index, DeleteMode mode);
 
@@ -2913,6 +2918,37 @@ class NumberDictionary: public Dictionary<NumberDictionaryShape, uint32_t> {
 };
 
 
+class ObjectDictionaryShape {
+ public:
+  static inline bool IsMatch(JSObject* key, Object* other);
+  static inline uint32_t Hash(JSObject* key);
+  static inline uint32_t HashForObject(JSObject* key, Object* object);
+  MUST_USE_RESULT static inline MaybeObject* AsObject(JSObject* key);
+  static const int kPrefixSize = 2;
+  static const int kEntrySize = 3;
+  static const bool kIsEnumerable = false;
+};
+
+
+class ObjectDictionary: public Dictionary<ObjectDictionaryShape, JSObject*> {

[Vitaly Repeshko, 2011/07/26 13:53:14]

Needs a comment.

[Michael Starzinger, 2011/07/26 22:30:23]

Fixed.

+ public:
+  static inline ObjectDictionary* cast(Object* obj) {
+    ASSERT(obj->IsDictionary());
+    return reinterpret_cast<ObjectDictionary*>(obj);
+  }
+
+  // Specialized version which checks whether objects have an identity hash.
+  int FindEntry(JSObject* key);
+  int FindEntry(Isolate* isolate, JSObject* key);

[Vitaly Repeshko, 2011/07/26 13:53:14]

Doesn't seem to be defined/called. Remove?

[Vitaly Repeshko, 2011/07/27 15:42:26]

Did you miss this one?

[Michael Starzinger, 2011/07/28 01:23:18]

Fixed. Yep, missed that one.

+
+  // Specialized version which makes sure objects have an identity hash.
+  MUST_USE_RESULT MaybeObject* Add(JSObject* key, Object* value);
+  MUST_USE_RESULT MaybeObject* Add(JSObject* key,

[Vitaly Repeshko, 2011/07/26 13:53:14]

Same here.

Are PropertyDetails really required? If not, change the entry size in the shape
to 2.

[Michael Starzinger, 2011/07/26 22:30:23]

In that case the ObjectDictionary should use HashTable instead of Dictionary as
a base class, because those PropertyDetails are the only difference (besides
being enumerable) between them. Right?

[Vitaly Repeshko, 2011/07/27 15:42:26]

Yes, Dictionaries are used for storing properties and elements. Change the base
class. Maybe the name should also be changed to ObjectHashTable.

[Michael Starzinger, 2011/07/28 01:23:18]

Fixed. Required a lot of other changes, but it becomes much cleaner now I think.
:)

+                                   Object* value,
+                                   PropertyDetails details);
+};
+
+
 // JSFunctionResultCache caches results of some JSFunction invocation.
 // It is a fixed array with fixed structure:
 //   [0]: factory function