Allow the morphing of strings to external strings to avoid having to...

src/objects.h

Index: src/objects.h
===================================================================
--- src/objects.h	(revision 1251)
+++ src/objects.h	(working copy)
@@ -945,7 +945,7 @@
 
   // Bits used by the marking phase of the garbage collector.
   //
-  // The first word of a heap object is normall a map pointer. The last two
+  // The first word of a heap object is normally a map pointer. The last two
   // bits are tagged as '01' (kHeapObjectTag). We reuse the last two bits to
   // mark an object as live and/or overflowed:
   //   last bit = 0, marked as alive
@@ -3205,6 +3205,10 @@
                                 uint32_t* index,
                                 int length);
 
+  // Externalization.
+  bool MakeExternal(v8::String::ExternalStringResource* resource);
+  bool MakeExternal(v8::String::ExternalAsciiStringResource* resource);
+
   // Conversion.
   inline bool AsArrayIndex(uint32_t* index);
 
@@ -3584,6 +3588,9 @@
                                                      unsigned* offset,
                                                      unsigned chars);
 
+  // Identify the map for the external string/symbol with a particular length.
+  static inline Map* StringMap(int length);
+  static inline Map* SymbolMap(int length);
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(ExternalAsciiString);
 };
@@ -3613,6 +3620,9 @@
                                                 unsigned* offset_ptr,
                                                 unsigned chars);
 
+  // Identify the map for the external string/symbol with a particular length.
+  static inline Map* StringMap(int length);
+  static inline Map* SymbolMap(int length);
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(ExternalTwoByteString);
 };