Improve Array.shift() performance for small arrays.

src/objects.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_OBJECTS_H_
 #define V8_OBJECTS_H_
 
 #include "allocation.h"
 #include "assert-scope.h"
 #include "builtins.h"
@@ skipping 6792 matching lines @@
 //
 // Each entry has a name of a global object property holding an object
 // optionally followed by ".prototype", a name of a builtin function
 // on the object (the one the id is set for), and a label.
 //
 // Installation of ids for the selected builtin functions is handled
 // by the bootstrapper.
 #define FUNCTIONS_WITH_ID_LIST(V)                   \
   V(Array.prototype, push, ArrayPush)               \
   V(Array.prototype, pop, ArrayPop)                 \
+  V(Array.prototype, shift, ArrayShift)             \
   V(Function.prototype, apply, FunctionApply)       \
   V(String.prototype, charCodeAt, StringCharCodeAt) \
   V(String.prototype, charAt, StringCharAt)         \
   V(String, fromCharCode, StringFromCharCode)       \
   V(Math, floor, MathFloor)                         \
   V(Math, round, MathRound)                         \
   V(Math, ceil, MathCeil)                           \
   V(Math, abs, MathAbs)                             \
   V(Math, log, MathLog)                             \
   V(Math, exp, MathExp)                             \
@@ skipping 4296 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_