[Interpreter] Adds support for const/let variables to interpreter.

src/compiler/interpreter-assembler.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_COMPILER_INTERPRETER_ASSEMBLER_H_
 #define V8_COMPILER_INTERPRETER_ASSEMBLER_H_
 
 // Clients of this interface shouldn't depend on lots of compiler internals.
 // Do not include anything from src/compiler here!
 #include "src/allocation.h"
@@ skipping 130 matching lines @@
   Node* CallRuntime(Runtime::FunctionId function_id, Node* arg1, Node* arg2);
   Node* CallRuntime(Runtime::FunctionId function_id, Node* arg1, Node* arg2,
                     Node* arg3);
   Node* CallRuntime(Runtime::FunctionId function_id, Node* arg1, Node* arg2,
                     Node* arg3, Node* arg4);
 
   // Jump relative to the current bytecode by |jump_offset|.
   void Jump(Node* jump_offset);
 
   // Jump relative to the current bytecode by |jump_offset| if the
+  // |condition| is true. Helper function for JumpIfWordEqual and
+  // JumpIfWordNotEqual.
+  void JumpConditional(Node* condition, Node* jump_offset);
+
+  // Jump relative to the current bytecode by |jump_offset| if the
   // word values |lhs| and |rhs| are equal.
   void JumpIfWordEqual(Node* lhs, Node* rhs, Node* jump_offset);
 
+  // Jump relative to the current bytecode by |jump_offset| if the
+  // word values |lhs| and |rhs| are not equal.
+  void JumpIfWordNotEqual(Node* lhs, Node* rhs, Node* jump_offset);
+
   // Perform a stack guard check.
   void StackCheck();
 
   // Returns from the function.
   void Return();
 
   // Dispatch to the bytecode.
   void Dispatch();
 
   // Abort with the given bailout reason.
@@ skipping 59 matching lines @@
   bool code_generated_;
 
   DISALLOW_COPY_AND_ASSIGN(InterpreterAssembler);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_INTERPRETER_ASSEMBLER_H_