[runtime] Introduce FastNewStrictArgumentsStub to optimize strict arguments.

src/objects.h

 // Copyright 2015 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 <iosfwd>
 
 #include "src/allocation.h"
@@ skipping 2588 matching lines @@
   static const int kWritableIndex = 1;
   static const int kEnumerableIndex = 2;
   static const int kConfigurableIndex = 3;
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(JSDataPropertyDescriptor);
 };
 
 
 // JSIteratorResult is just a JSObject with a specific initial map.
-// This initial map adds in-object properties for "done" and "value,
+// This initial map adds in-object properties for "done" and "value",
 // as specified by ES6 section 25.1.1.3 The IteratorResult Interface
 class JSIteratorResult: public JSObject {
  public:
   // Offsets of object fields.
   static const int kValueOffset = JSObject::kHeaderSize;
   static const int kDoneOffset = kValueOffset + kPointerSize;
   static const int kSize = kDoneOffset + kPointerSize;
   // Indices of in-object properties.
   static const int kValueIndex = 0;
   static const int kDoneIndex = 1;
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(JSIteratorResult);
 };
 
 
+// Common superclass for JSSloppyArgumentsObject and JSStrictArgumentsObject.
+class JSArgumentsObject: public JSObject {
+ public:
+  // Offsets of object fields.
+  static const int kLengthOffset = JSObject::kHeaderSize;
+  static const int kHeaderSize = kLengthOffset + kPointerSize;
+  // Indices of in-object properties.
+  static const int kLengthIndex = 0;
+
+ private:
+  DISALLOW_IMPLICIT_CONSTRUCTORS(JSArgumentsObject);
+};
+
+
+// JSSloppyArgumentsObject is just a JSObject with specific initial map.
+// This initial map adds in-object properties for "length" and "callee".
+class JSSloppyArgumentsObject: public JSArgumentsObject {
+ public:
+  // Offsets of object fields.
+  static const int kCalleeOffset = JSArgumentsObject::kHeaderSize;
+  static const int kSize = kCalleeOffset + kPointerSize;
+  // Indices of in-object properties.
+  static const int kCalleeIndex = 1;
+
+ private:
+  DISALLOW_IMPLICIT_CONSTRUCTORS(JSSloppyArgumentsObject);
+};
+
+
+// JSStrictArgumentsObject is just a JSObject with specific initial map.
+// This initial map adds an in-object property for "length".
+class JSStrictArgumentsObject: public JSArgumentsObject {
+ public:
+  // Offsets of object fields.
+  static const int kSize = JSArgumentsObject::kHeaderSize;
+
+ private:
+  DISALLOW_IMPLICIT_CONSTRUCTORS(JSStrictArgumentsObject);
+};
+
+
 // Common superclass for FixedArrays that allow implementations to share
 // common accessors and some code paths.
 class FixedArrayBase: public HeapObject {
  public:
   // [length]: length of the array.
   inline int length() const;
   inline void set_length(int value);
 
   // Get and set the length using acquire loads and release stores.
   inline int synchronized_length() const;
@@ skipping 8172 matching lines @@
     }
     return value;
   }
 };
 
 
 }  // NOLINT, false-positive due to second-order macros.
 }  // NOLINT, false-positive due to second-order macros.
 
 #endif  // V8_OBJECTS_H_