diff --git a/src/google/protobuf/message.cc b/src/google/protobuf/message.cc
index 4a3e3e5c8e..866c214543 100644
--- a/src/google/protobuf/message.cc
+++ b/src/google/protobuf/message.cc
@@ -185,13 +185,7 @@ size_t Message::MaybeComputeUnknownFieldsSize(
 }
 
 size_t Message::SpaceUsedLong() const {
-  auto* reflection = GetReflection();
-  if (PROTOBUF_PREDICT_TRUE(reflection != nullptr)) {
-    return reflection->SpaceUsedLong(*this);
-  }
-  // The only case that does not have reflection is RawMessage.
-  return internal::DownCast<const internal::RawMessageBase&>(*this)
-      .SpaceUsedLong();
+  return GetClassData()->full().descriptor_methods->space_used_long(*this);
 }
 
 static std::string GetTypeNameImpl(const MessageLite& msg) {
@@ -207,11 +201,17 @@ const internal::TcParseTableBase* Message::GetTcParseTableImpl(
   return DownCast<const Message&>(msg).GetReflection()->GetTcParseTable();
 }
 
+size_t Message::SpaceUsedLongImpl(const MessageLite& msg_lite) {
+  auto& msg = DownCast<const Message&>(msg_lite);
+  return msg.GetReflection()->SpaceUsedLong(msg);
+}
+
 PROTOBUF_CONSTINIT const MessageLite::DescriptorMethods
     Message::kDescriptorMethods = {
         GetTypeNameImpl,
         InitializationErrorStringImpl,
         GetTcParseTableImpl,
+        SpaceUsedLongImpl,
 };
 
 namespace internal {
diff --git a/src/google/protobuf/message.h b/src/google/protobuf/message.h
index 22ab4c28ae..876a57cc08 100644
--- a/src/google/protobuf/message.h
+++ b/src/google/protobuf/message.h
@@ -386,6 +386,8 @@ class PROTOBUF_EXPORT Message : public MessageLite {
   static const internal::TcParseTableBase* GetTcParseTableImpl(
       const MessageLite& msg);
 
+  static size_t SpaceUsedLongImpl(const MessageLite& msg_lite);
+
   static const DescriptorMethods kDescriptorMethods;
 
 };
@@ -1629,12 +1631,6 @@ bool SplitFieldHasExtraIndirectionStatic(const FieldDescriptor* field) {
   return SplitFieldHasExtraIndirection(field);
 }
 
-class RawMessageBase : public Message {
- public:
-  using Message::Message;
-  virtual size_t SpaceUsedLong() const = 0;
-};
-
 inline void MaybePoisonAfterClear(Message* root) {
   if (root == nullptr) return;
 #ifndef PROTOBUF_ASAN
diff --git a/src/google/protobuf/message_lite.h b/src/google/protobuf/message_lite.h
index fc14e810c5..00a5481909 100644
--- a/src/google/protobuf/message_lite.h
+++ b/src/google/protobuf/message_lite.h
@@ -537,6 +537,7 @@ class PROTOBUF_EXPORT MessageLite {
     std::string (*get_type_name)(const MessageLite&);
     std::string (*initialization_error_string)(const MessageLite&);
     const internal::TcParseTableBase* (*get_tc_table)(const MessageLite&);
+    size_t (*space_used_long)(const MessageLite&);
   };
   struct ClassDataFull;
   // Note: The order of arguments in the functions is chosen so that it has