[interpreter] Move temporary register allocator into own file.

src/interpreter/bytecodes.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_INTERPRETER_BYTECODES_H_
 #define V8_INTERPRETER_BYTECODES_H_
 
 #include <iosfwd>
 
 // Clients of this interface shouldn't depend on lots of interpreter internals.
@@ skipping 300 matching lines @@
   bool is_valid() const { return index_ != kInvalidIndex; }
   bool is_byte_operand() const;
   bool is_short_operand() const;
 
   static Register FromParameterIndex(int index, int parameter_count);
   int ToParameterIndex(int parameter_count) const;
   static int MaxParameterIndex();
   static int MaxRegisterIndex();
   static int MaxRegisterIndexForByteOperand();
 
+  // Returns an invalid register.
+  static Register invalid_value() { return Register(); }
+
   // Returns the register for the function's closure object.
   static Register function_closure();
   bool is_function_closure() const;
 
   // Returns the register which holds the current context object.
   static Register current_context();
   bool is_current_context() const;
 
   // Returns the register for the incoming new target value.
   static Register new_target();
@@ skipping 141 matching lines @@
 
 std::ostream& operator<<(std::ostream& os, const Bytecode& bytecode);
 std::ostream& operator<<(std::ostream& os, const OperandType& operand_type);
 std::ostream& operator<<(std::ostream& os, const OperandSize& operand_type);
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_INTERPRETER_BYTECODES_H_