[runtime] Optimize and unify rest parameters.

src/interpreter/interpreter.cc

Index: src/interpreter/interpreter.cc
diff --git a/src/interpreter/interpreter.cc b/src/interpreter/interpreter.cc
index 09fac9430e35ffcd946e92d809955dce222283b9..6f64d63eb7e7cd6e344418c4cb5e5b76ce082c1c 100644
--- a/src/interpreter/interpreter.cc
+++ b/src/interpreter/interpreter.cc
@@ -1772,16 +1772,14 @@ void Interpreter::DoCreateUnmappedArguments(
   __ Dispatch();
 }
 
-// CreateRestArguments
+// CreateRestParameter
 //
-// Creates a new rest arguments object starting at |rest_index|.
-void Interpreter::DoCreateRestArguments(
+// Creates a new rest parameter array.
+void Interpreter::DoCreateRestParameter(
     compiler::InterpreterAssembler* assembler) {
+  // TODO(ignition): Use FastNewRestParameterStub here.
   Node* closure = __ LoadRegister(Register::function_closure());
-  Node* constant_pool_index = __ BytecodeOperandIdx(0);
-  Node* rest_index = __ LoadConstantPoolEntry(constant_pool_index);
-  Node* result =
-      __ CallRuntime(Runtime::kNewRestArguments_Generic, closure, rest_index);
+  Node* result = __ CallRuntime(Runtime::kNewRestParameter, closure);
   __ SetAccumulator(result);
   __ Dispatch();
 }