Provide private symbols through internal APIs

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index c0835e21eb9cb5d3df0d1f5ad1e464b6d4022323..2b8e3b20236e24208b8d8ffe5d52f443617710ad 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -123,6 +123,7 @@
 //               - ExternalAsciiInternalizedString
 //               - ExternalTwoByteInternalizedString
 //         - Symbol
+//           - Private
 //       - HeapNumber
 //       - Cell
 //         - PropertyCell
@@ -359,6 +360,7 @@ const int kStubMinorKeyBits = kBitsPerInt - kSmiTagSize - kStubMajorKeyBits;
   V(SHORT_EXTERNAL_INTERNALIZED_STRING_WITH_ONE_BYTE_DATA_TYPE)                \
                                                                                \
   V(SYMBOL_TYPE)                                                               \
+                                                                               \

[Yang, 2013/10/29 12:47:26]

stray edit?

[rossberg, 2013/10/29 15:08:19]

On purpose. :)

   V(MAP_TYPE)                                                                  \
   V(CODE_TYPE)                                                                 \
   V(ODDBALL_TYPE)                                                              \
@@ -691,7 +693,7 @@ enum InstanceType {
       | kNotInternalizedTag,
 
   // Non-string names
-  SYMBOL_TYPE = kNotStringTag,  // LAST_NAME_TYPE, FIRST_NONSTRING_TYPE
+  SYMBOL_TYPE = kNotStringTag,  // FIRST_NONSTRING_TYPE, LAST_NAME_TYPE
 
   // Objects allocated in their own spaces (never in new space).
   MAP_TYPE,
@@ -1384,6 +1386,7 @@ class Object : public MaybeObject {
   INLINE(bool IsUninitialized());
   INLINE(bool IsTrue());
   INLINE(bool IsFalse());
+  INLINE(bool IsPrivate());
   inline bool IsArgumentsMarker();
   inline bool NonFailureIsHeapObject();
 
@@ -8330,10 +8333,11 @@ class Name: public HeapObject {
 };
 
 
-// ES6 symbols.
+// ES6 unique symbols.
 class Symbol: public Name {
  public:
-  // [name]: the print name of a symbol, or undefined if none.
+  // [name]: the print name of a symbol, or undefined if none,
+  // or for private symbols, a Box containing one of those.
   DECL_ACCESSORS(name, Object)
 
   // Casting.
@@ -8355,6 +8359,20 @@ class Symbol: public Name {
 };
 
 
+// Private symbols.
+class Private: public Symbol {
+ public:
+  // The print name of a private symbol, or undefined if none.
+  DECL_ACCESSORS(name, Object)
+
+  // Casting.
+  static inline Private* cast(Object* obj);
+
+ private:
+  DISALLOW_IMPLICIT_CONSTRUCTORS(Private);
+};
+
+
 class ConsString;
 
 // The String abstract class captures JavaScript string values: