Better support for 'polymorphic' JS and external arrays

src/arm/macro-assembler-arm.cc

Index: src/arm/macro-assembler-arm.cc
diff --git a/src/arm/macro-assembler-arm.cc b/src/arm/macro-assembler-arm.cc
index 889e9815a01526829c4efffdc363da41e342df72..15a50a153496c53f2087db8f37bdeec5add9e98e 100644
--- a/src/arm/macro-assembler-arm.cc
+++ b/src/arm/macro-assembler-arm.cc
@@ -1681,6 +1681,23 @@ void MacroAssembler::CheckMap(Register obj,
 }
 
 
+void MacroAssembler::DispatchMap(Register obj,
+                                 Register scratch,
+                                 Handle<Map> map,
+                                 Handle<Code> success,
+                                 bool is_heap_object) {
+  Label fail;
+  if (!is_heap_object) {
+    JumpIfSmi(obj, &fail);
+  }
+  ldr(scratch, FieldMemOperand(obj, HeapObject::kMapOffset));
+  mov(ip, Operand(map));
+  cmp(scratch, ip);
+  Jump(success, RelocInfo::CODE_TARGET, eq);
+  bind(&fail);
+}
+
+
 void MacroAssembler::TryGetFunctionPrototype(Register function,
                                              Register result,
                                              Register scratch,