Add a fast case to Array.join when all the elements and the separator are fla...

src/runtime.h

 // Copyright 2010 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 400 matching lines @@
   F(IsFunction, 1, 1)                                                        \
   F(IsUndetectableObject, 1, 1)                                              \
   F(IsSpecObject, 1, 1)                                                      \
   F(IsStringWrapperSafeForDefaultValueOf, 1, 1)                              \
   F(MathPow, 2, 1)                                                           \
   F(MathSin, 1, 1)                                                           \
   F(MathCos, 1, 1)                                                           \
   F(MathSqrt, 1, 1)                                                          \
   F(IsRegExpEquivalent, 2, 1)                                                \
   F(HasCachedArrayIndex, 1, 1)                                               \
-  F(GetCachedArrayIndex, 1, 1)
+  F(GetCachedArrayIndex, 1, 1)                                               \
+  F(FastAsciiArrayJoin, 2, 1)
 
 
 // ----------------------------------------------------------------------------
 // INLINE_AND_RUNTIME_FUNCTION_LIST defines all inlined functions accessed
 // with a native call of the form %_name from within JS code that also have
 // a corresponding runtime function, that is called for slow cases.
 // Entries have the form F(name, number of arguments, number of return values).
 #define INLINE_RUNTIME_FUNCTION_LIST(F) \
   F(IsConstructCall, 0, 1)                                                   \
   F(ClassOf, 1, 1)                                                           \
@@ skipping 102 matching lines @@
                                                 int position);
 
   // Helper functions used stubs.
   static void PerformGC(Object* result);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_RUNTIME_H_