[runtime] Optimize and unify rest parameters.

src/full-codegen/arm/full-codegen-arm.cc

Index: src/full-codegen/arm/full-codegen-arm.cc
diff --git a/src/full-codegen/arm/full-codegen-arm.cc b/src/full-codegen/arm/full-codegen-arm.cc
index a8262c76836e6e00304065314589c00c50d9d1c1..642671af18e80d1a80db971c7bfc78aec0339928 100644
--- a/src/full-codegen/arm/full-codegen-arm.cc
+++ b/src/full-codegen/arm/full-codegen-arm.cc
@@ -264,21 +264,12 @@ void FullCodeGenerator::Generate() {
   Variable* rest_param = scope()->rest_parameter(&rest_index);
   if (rest_param) {
     Comment cmnt(masm_, "[ Allocate rest parameter array");
-
-    int num_parameters = info->scope()->num_parameters();
-    int offset = num_parameters * kPointerSize;
-
-    __ mov(RestParamAccessDescriptor::parameter_count(),
-           Operand(Smi::FromInt(num_parameters)));
-    __ add(RestParamAccessDescriptor::parameter_pointer(), fp,
-           Operand(StandardFrameConstants::kCallerSPOffset + offset));
-    __ mov(RestParamAccessDescriptor::rest_parameter_index(),
-           Operand(Smi::FromInt(rest_index)));
-    function_in_register_r1 = false;
-
-    RestParamAccessStub stub(isolate());
+    if (!function_in_register_r1) {
+      __ ldr(r1, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset));
+    }
+    FastNewRestParameterStub stub(isolate());
     __ CallStub(&stub);
-
+    function_in_register_r1 = false;
     SetVar(rest_param, r0, r1, r2);
   }