Our JavaScriptFrame::function_slot_object is arch independent.

src/frames-inl.h

Index: src/frames-inl.h
diff --git a/src/frames-inl.h b/src/frames-inl.h
index 650d6f9725f4ab30df736034093d6b426bbc2fb9..e69bcd90338dd8f56fe7c87c5c5f0194f499ff38 100644
--- a/src/frames-inl.h
+++ b/src/frames-inl.h
@@ -217,6 +217,12 @@ inline JSFunction* JavaScriptFrame::function() const {
 }
 
 
+inline Object* JavaScriptFrame::function_slot_object() const {
+  const int offset = JavaScriptFrameConstants::kFunctionOffset;
+  return Memory::Object_at(fp() + offset);
+}
+
+
 inline StubFrame::StubFrame(StackFrameIteratorBase* iterator)
     : StandardFrame(iterator) {
 }