Bring r4503 to the 2.1 branch....

src/ia32/stub-cache-ia32.cc

Index: src/ia32/stub-cache-ia32.cc
===================================================================
--- src/ia32/stub-cache-ia32.cc	(revision 4551)
+++ src/ia32/stub-cache-ia32.cc	(working copy)
@@ -1223,6 +1223,11 @@
   // -----------------------------------
   ASSERT(check == RECEIVER_MAP_CHECK);
 
+  // If object is not an array, bail out to regular call.
+  if (!object->IsJSArray()) {
+    return Heap::undefined_value();
+  }
+
   Label miss;
 
   // Get the receiver from the stack.
@@ -1371,6 +1376,11 @@
   // -----------------------------------
   ASSERT(check == RECEIVER_MAP_CHECK);
 
+  // If object is not an array, bail out to regular call.
+  if (!object->IsJSArray()) {
+    return Heap::undefined_value();
+  }
+
   Label miss, empty_array, call_builtin;
 
   // Get the receiver from the stack.
@@ -1458,7 +1468,11 @@
   if (function_info->HasCustomCallGenerator()) {
     CustomCallGenerator generator =
         ToCData<CustomCallGenerator>(function_info->function_data());
-    return generator(this, object, holder, function, name, check);
+    Object* result = generator(this, object, holder, function, name, check);
+    // undefined means bail out to regular compiler.
+    if (!result->IsUndefined()) {
+      return result;
+    }
   }
 
   Label miss_in_smi_check;