Make sure transitioned arrays efficiently call builtin Array functions

src/arm/macro-assembler-arm.h

Index: src/arm/macro-assembler-arm.h
diff --git a/src/arm/macro-assembler-arm.h b/src/arm/macro-assembler-arm.h
index 392c2f7503fee193086b73ed2986e158c1772985..20db22f46f0f4ac540eee55bbee004e8f9ee38a0 100644
--- a/src/arm/macro-assembler-arm.h
+++ b/src/arm/macro-assembler-arm.h
@@ -1,4 +1,4 @@
-// Copyright 2011 the V8 project authors. All rights reserved.
+// Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
@@ -790,15 +790,26 @@ class MacroAssembler: public Assembler {
                                    Register scratch4,
                                    Label* fail);
 
-  // Check if the map of an object is equal to a specified map (either
-  // given directly or as an index into the root list) and branch to
-  // label if not. Skip the smi check if not required (object is known
-  // to be a heap object)
+  // Compare an object's map with the specified map and its transitioned
+  // elements maps if mode is ALLOW_ELEMENT_TRANSITION_MAPS. Condition flags are
+  // set with result of map compare. If multiple map compares are required, the
+  // compare sequences branches to early_success.
+  void CompareMap(Register obj,
+                  Register scratch,
+                  Handle<Map> map,
+                  Label* early_success,
+                  CompareMapMode mode = REQUIRE_EXACT_MAP);
+
+  // Check if the map of an object is equal to a specified map and branch to
+  // label if not. Skip the smi check if not required (object is known to be a
+  // heap object). If mode is ALLOW_ELEMENT_TRANSITION_MAPS, then also match
+  // against maps that are ElementsKind transition maps of the specificed map.
   void CheckMap(Register obj,
                 Register scratch,
                 Handle<Map> map,
                 Label* fail,
-                SmiCheckType smi_check_type);
+                SmiCheckType smi_check_type,
+                CompareMapMode mode = REQUIRE_EXACT_MAP);
 
 
   void CheckMap(Register obj,