Inline the stub functions in custom vtable mode.

That way we avoid the extra function call and they behave more like normal
virtual functions.
Has no effect in normal mode.

PiperOrigin-RevId: 654039245

src/google/protobuf/message_lite.cc

@@ -64,23 +64,6 @@ void MessageLite::CheckTypeAndMergeFrom(const MessageLite& other) {
   data->merge_to_from(*this, other);
 }
 
-#if defined(PROTOBUF_CUSTOM_VTABLE)
-uint8_t* MessageLite::_InternalSerialize(
-    uint8_t* ptr, io::EpsCopyOutputStream* stream) const {
-  return _class_data_->serialize(*this, ptr, stream);
-}
-
-MessageLite* MessageLite::New(Arena* arena) const {
-  return static_cast<MessageLite*>(_class_data_->new_message(this, arena));
-}
-
-void MessageLite::Clear() { _class_data_->clear(*this); }
-
-size_t MessageLite::ByteSizeLong() const {
-  return _class_data_->byte_size_long(*this);
-}
-#endif  // PROTOBUF_CUSTOM_VTABLE
-
 bool MessageLite::IsInitialized() const {
   auto* data = GetClassData();
   return data->is_initialized != nullptr ? data->is_initialized(*this) : true;
@@ -137,7 +120,9 @@ std::string MessageLite::DebugString() const {
   return absl::StrCat("MessageLite at 0x", absl::Hex(this));
 }
 
+#if !defined(PROTOBUF_CUSTOM_VTABLE)
 int MessageLite::GetCachedSize() const { return AccessCachedSize().Get(); }
+#endif
 
 namespace {
 

src/google/protobuf/message_lite.h

@@ -229,7 +229,9 @@ class PROTOBUF_EXPORT MessageLite {
   // Construct a new instance on the arena. Ownership is passed to the caller
   // if arena is a nullptr.
 #if defined(PROTOBUF_CUSTOM_VTABLE)
-  MessageLite* New(Arena* arena) const;
+  MessageLite* New(Arena* arena) const {
+    return static_cast<MessageLite*>(_class_data_->new_message(this, arena));
+  }
 #else
   virtual MessageLite* New(Arena* arena) const = 0;
 #endif  // PROTOBUF_CUSTOM_VTABLE
@@ -246,7 +248,7 @@ class PROTOBUF_EXPORT MessageLite {
   // will likely be needed again, so the memory used may not be freed.
   // To ensure that all memory used by a Message is freed, you must delete it.
 #if defined(PROTOBUF_CUSTOM_VTABLE)
-  void Clear();
+  void Clear() { _class_data_->clear(*this); }
 #else
   virtual void Clear() = 0;
 #endif  // PROTOBUF_CUSTOM_VTABLE
@@ -470,7 +472,7 @@ class PROTOBUF_EXPORT MessageLite {
   // ByteSizeLong() is generally linear in the number of fields defined for the
   // proto.
 #if defined(PROTOBUF_CUSTOM_VTABLE)
-  size_t ByteSizeLong() const;
+  size_t ByteSizeLong() const { return _class_data_->byte_size_long(*this); }
 #else
   virtual size_t ByteSizeLong() const = 0;
 #endif  // PROTOBUF_CUSTOM_VTABLE
@@ -512,7 +514,11 @@ class PROTOBUF_EXPORT MessageLite {
   // sub-message is changed, all of its parents' cached sizes would need to be
   // invalidated, which is too much work for an otherwise inlined setter
   // method.)
+#if defined(PROTOBUF_CUSTOM_VTABLE)
+  int GetCachedSize() const { return AccessCachedSize().Get(); }
+#else
   int GetCachedSize() const;
+#endif
 
   const char* _InternalParse(const char* ptr, internal::ParseContext* ctx);
 
@@ -795,7 +801,9 @@ class PROTOBUF_EXPORT MessageLite {
   //  uint8_t* _InternalSerialize(uint8_t* ptr) const;
 #if defined(PROTOBUF_CUSTOM_VTABLE)
   uint8_t* _InternalSerialize(uint8_t* ptr,
-                              io::EpsCopyOutputStream* stream) const;
+                              io::EpsCopyOutputStream* stream) const {
+    return _class_data_->serialize(*this, ptr, stream);
+  }
 #else   // PROTOBUF_CUSTOM_VTABLE
   virtual uint8_t* _InternalSerialize(
       uint8_t* ptr, io::EpsCopyOutputStream* stream) const = 0;