Revert of Revert [TypeFeedbackVector] Root literal arrays in function literal slots

src/objects-inl.h

Index: src/objects-inl.h
diff --git a/src/objects-inl.h b/src/objects-inl.h
index 21278929c4f145df795179598b0dd66ca5bacfb3..65f12cadfb318271696cc9c192ecfee5a0a0e7db 100644
--- a/src/objects-inl.h
+++ b/src/objects-inl.h
@@ -3453,12 +3453,16 @@
   return reinterpret_cast<LiteralsArray*>(object);
 }
 
+bool LiteralsArray::has_feedback_vector() const {
+  return !get(kVectorIndex)->IsUndefined(this->GetIsolate());
+}
 
 TypeFeedbackVector* LiteralsArray::feedback_vector() const {
-  if (length() == 0) {
+  if (length() == 0 || !has_feedback_vector()) {
     return TypeFeedbackVector::cast(
-        const_cast<FixedArray*>(FixedArray::cast(this)));
-  }
+        this->GetIsolate()->heap()->empty_type_feedback_vector());
+  }
+
   return TypeFeedbackVector::cast(get(kVectorIndex));
 }
 
@@ -6594,6 +6598,13 @@
   }
 }
 
+bool JSFunction::has_literals_array() const {
+  SharedFunctionInfo* shared = this->shared();
+
+  return (literals() != shared->GetIsolate()->heap()->empty_literals_array() ||
+          (shared->feedback_metadata()->slot_count() == 0 &&
+           shared->num_literals() == 0));
+}
 
 Context* JSFunction::context() {
   return Context::cast(READ_FIELD(this, kContextOffset));