In OSS mode omit some extern template specializations. We have seen reports of

compilers falling over due to the size of translation units.

PiperOrigin-RevId: 549653990

src/google/protobuf/compiler/cpp/file.cc

@@ -1242,13 +1242,20 @@ class FileGenerator::ForwardDeclarations {
   }
 
   void PrintTopLevelDecl(io::Printer* p, const Options& options) const {
+    if (ShouldGenerateExternSpecializations(options)) {
       for (const auto& c : classes_) {
+        // To reduce total linker input size in large binaries we make these
+        // functions extern and define then in the pb.cc file. This avoids bloat
+        // in callers by having duplicate definitions of the template.
+        // However, it increases the size of the pb.cc translation units so it
+        // is a tradeoff.
         p->Emit({{"class", QualifiedClassName(c.second, options)}}, R"cc(
           template <>
           $dllexport_decl $$class$* Arena::CreateMaybeMessage<$class$>(Arena*);
         )cc");
       }
     }
+  }
 
  private:
   absl::btree_map<std::string, const Descriptor*> classes_;

src/google/protobuf/compiler/cpp/helpers.h

@@ -1008,6 +1008,14 @@ void GenerateUtf8CheckCodeForCord(io::Printer* p, const FieldDescriptor* field,
                                   const Options& options, bool for_parse,
                                   absl::string_view parameters);
 
+inline bool ShouldGenerateExternSpecializations(const Options& options) {
+  // For OSS we omit the specializations to reduce codegen size.
+  // Some compilers can't handle that much input in a single translation unit.
+  // These specializations are just a link size optimization and do not affect
+  // correctness or performance, so it is ok to omit them.
+  return !options.opensource_runtime;
+}
+
 struct OneOfRangeImpl {
   struct Iterator {
     using iterator_category = std::forward_iterator_tag;

src/google/protobuf/compiler/cpp/message.cc

@@ -2953,12 +2953,14 @@ void MessageGenerator::GenerateSourceInProto2Namespace(io::Printer* p) {
   auto v = p->WithVars(ClassVars(descriptor_, options_));
   auto t = p->WithVars(MakeTrackerCalls(descriptor_, options_));
   Formatter format(p);
+  if (ShouldGenerateExternSpecializations(options_)) {
     format(
         "template<> "
         "PROTOBUF_NOINLINE $classtype$*\n"
         "Arena::CreateMaybeMessage< $classtype$ >(Arena* arena) {\n"
         "  return Arena::CreateMessageInternal< $classtype$ >(arena);\n"
         "}\n");
+  }
 }
 
 void MessageGenerator::GenerateClear(io::Printer* p) {

src/google/protobuf/compiler/plugin.pb.cc

@@ -1584,22 +1584,6 @@ void CodeGeneratorResponse::InternalSwap(CodeGeneratorResponse* other) {
 }  // namespace google
 namespace google {
 namespace protobuf {
-template<> PROTOBUF_NOINLINE ::google::protobuf::compiler::Version*
-Arena::CreateMaybeMessage< ::google::protobuf::compiler::Version >(Arena* arena) {
-  return Arena::CreateMessageInternal< ::google::protobuf::compiler::Version >(arena);
-}
-template<> PROTOBUF_NOINLINE ::google::protobuf::compiler::CodeGeneratorRequest*
-Arena::CreateMaybeMessage< ::google::protobuf::compiler::CodeGeneratorRequest >(Arena* arena) {
-  return Arena::CreateMessageInternal< ::google::protobuf::compiler::CodeGeneratorRequest >(arena);
-}
-template<> PROTOBUF_NOINLINE ::google::protobuf::compiler::CodeGeneratorResponse_File*
-Arena::CreateMaybeMessage< ::google::protobuf::compiler::CodeGeneratorResponse_File >(Arena* arena) {
-  return Arena::CreateMessageInternal< ::google::protobuf::compiler::CodeGeneratorResponse_File >(arena);
-}
-template<> PROTOBUF_NOINLINE ::google::protobuf::compiler::CodeGeneratorResponse*
-Arena::CreateMaybeMessage< ::google::protobuf::compiler::CodeGeneratorResponse >(Arena* arena) {
-  return Arena::CreateMessageInternal< ::google::protobuf::compiler::CodeGeneratorResponse >(arena);
-}
 }  // namespace protobuf
 }  // namespace google
 // @@protoc_insertion_point(global_scope)

src/google/protobuf/compiler/plugin.pb.h

@@ -77,14 +77,6 @@ class Version;
 struct VersionDefaultTypeInternal;
 PROTOC_EXPORT extern VersionDefaultTypeInternal _Version_default_instance_;
 }  // namespace compiler
-template <>
-PROTOC_EXPORT ::google::protobuf::compiler::CodeGeneratorRequest* Arena::CreateMaybeMessage<::google::protobuf::compiler::CodeGeneratorRequest>(Arena*);
-template <>
-PROTOC_EXPORT ::google::protobuf::compiler::CodeGeneratorResponse* Arena::CreateMaybeMessage<::google::protobuf::compiler::CodeGeneratorResponse>(Arena*);
-template <>
-PROTOC_EXPORT ::google::protobuf::compiler::CodeGeneratorResponse_File* Arena::CreateMaybeMessage<::google::protobuf::compiler::CodeGeneratorResponse_File>(Arena*);
-template <>
-PROTOC_EXPORT ::google::protobuf::compiler::Version* Arena::CreateMaybeMessage<::google::protobuf::compiler::Version>(Arena*);
 }  // namespace protobuf
 }  // namespace google
 

src/google/protobuf/cpp_features.pb.cc

@@ -296,10 +296,6 @@ PROTOBUF_CONSTINIT PROTOBUF_EXPORT PROTOBUF_ATTRIBUTE_INIT_PRIORITY2
 }  // namespace pb
 namespace google {
 namespace protobuf {
-template<> PROTOBUF_NOINLINE ::pb::CppFeatures*
-Arena::CreateMaybeMessage< ::pb::CppFeatures >(Arena* arena) {
-  return Arena::CreateMessageInternal< ::pb::CppFeatures >(arena);
-}
 }  // namespace protobuf
 }  // namespace google
 // @@protoc_insertion_point(global_scope)

src/google/protobuf/cpp_features.pb.h

@@ -61,8 +61,6 @@ PROTOBUF_EXPORT extern CppFeaturesDefaultTypeInternal _CppFeatures_default_insta
 }  // namespace pb
 namespace google {
 namespace protobuf {
-template <>
-PROTOBUF_EXPORT ::pb::CppFeatures* Arena::CreateMaybeMessage<::pb::CppFeatures>(Arena*);
 }  // namespace protobuf
 }  // namespace google
 

src/google/protobuf/descriptor.pb.cc

@@ -13122,126 +13122,6 @@ void GeneratedCodeInfo::InternalSwap(GeneratedCodeInfo* other) {
 }  // namespace google
 namespace google {
 namespace protobuf {
-template<> PROTOBUF_NOINLINE ::google::protobuf::FileDescriptorSet*
-Arena::CreateMaybeMessage< ::google::protobuf::FileDescriptorSet >(Arena* arena) {
-  return Arena::CreateMessageInternal< ::google::protobuf::FileDescriptorSet >(arena);
-}
-template<> PROTOBUF_NOINLINE ::google::protobuf::FileDescriptorProto*
-Arena::CreateMaybeMessage< ::google::protobuf::FileDescriptorProto >(Arena* arena) {
-  return Arena::CreateMessageInternal< ::google::protobuf::FileDescriptorProto >(arena);
-}
-template<> PROTOBUF_NOINLINE ::google::protobuf::DescriptorProto_ExtensionRange*
-Arena::CreateMaybeMessage< ::google::protobuf::DescriptorProto_ExtensionRange >(Arena* arena) {
-  return Arena::CreateMessageInternal< ::google::protobuf::DescriptorProto_ExtensionRange >(arena);
-}
-template<> PROTOBUF_NOINLINE ::google::protobuf::DescriptorProto_ReservedRange*
-Arena::CreateMaybeMessage< ::google::protobuf::DescriptorProto_ReservedRange >(Arena* arena) {
-  return Arena::CreateMessageInternal< ::google::protobuf::DescriptorProto_ReservedRange >(arena);
-}
-template<> PROTOBUF_NOINLINE ::google::protobuf::DescriptorProto*
-Arena::CreateMaybeMessage< ::google::protobuf::DescriptorProto >(Arena* arena) {
-  return Arena::CreateMessageInternal< ::google::protobuf::DescriptorProto >(arena);
-}
-template<> PROTOBUF_NOINLINE ::google::protobuf::ExtensionRangeOptions_Declaration*
-Arena::CreateMaybeMessage< ::google::protobuf::ExtensionRangeOptions_Declaration >(Arena* arena) {
-  return Arena::CreateMessageInternal< ::google::protobuf::ExtensionRangeOptions_Declaration >(arena);
-}
-template<> PROTOBUF_NOINLINE ::google::protobuf::ExtensionRangeOptions*
-Arena::CreateMaybeMessage< ::google::protobuf::ExtensionRangeOptions >(Arena* arena) {
-  return Arena::CreateMessageInternal< ::google::protobuf::ExtensionRangeOptions >(arena);
-}
-template<> PROTOBUF_NOINLINE ::google::protobuf::FieldDescriptorProto*
-Arena::CreateMaybeMessage< ::google::protobuf::FieldDescriptorProto >(Arena* arena) {
-  return Arena::CreateMessageInternal< ::google::protobuf::FieldDescriptorProto >(arena);
-}
-template<> PROTOBUF_NOINLINE ::google::protobuf::OneofDescriptorProto*
-Arena::CreateMaybeMessage< ::google::protobuf::OneofDescriptorProto >(Arena* arena) {
-  return Arena::CreateMessageInternal< ::google::protobuf::OneofDescriptorProto >(arena);
-}
-template<> PROTOBUF_NOINLINE ::google::protobuf::EnumDescriptorProto_EnumReservedRange*
-Arena::CreateMaybeMessage< ::google::protobuf::EnumDescriptorProto_EnumReservedRange >(Arena* arena) {
-  return Arena::CreateMessageInternal< ::google::protobuf::EnumDescriptorProto_EnumReservedRange >(arena);
-}
-template<> PROTOBUF_NOINLINE ::google::protobuf::EnumDescriptorProto*
-Arena::CreateMaybeMessage< ::google::protobuf::EnumDescriptorProto >(Arena* arena) {
-  return Arena::CreateMessageInternal< ::google::protobuf::EnumDescriptorProto >(arena);
-}
-template<> PROTOBUF_NOINLINE ::google::protobuf::EnumValueDescriptorProto*
-Arena::CreateMaybeMessage< ::google::protobuf::EnumValueDescriptorProto >(Arena* arena) {
-  return Arena::CreateMessageInternal< ::google::protobuf::EnumValueDescriptorProto >(arena);
-}
-template<> PROTOBUF_NOINLINE ::google::protobuf::ServiceDescriptorProto*
-Arena::CreateMaybeMessage< ::google::protobuf::ServiceDescriptorProto >(Arena* arena) {
-  return Arena::CreateMessageInternal< ::google::protobuf::ServiceDescriptorProto >(arena);
-}
-template<> PROTOBUF_NOINLINE ::google::protobuf::MethodDescriptorProto*
-Arena::CreateMaybeMessage< ::google::protobuf::MethodDescriptorProto >(Arena* arena) {
-  return Arena::CreateMessageInternal< ::google::protobuf::MethodDescriptorProto >(arena);
-}
-template<> PROTOBUF_NOINLINE ::google::protobuf::FileOptions*
-Arena::CreateMaybeMessage< ::google::protobuf::FileOptions >(Arena* arena) {
-  return Arena::CreateMessageInternal< ::google::protobuf::FileOptions >(arena);
-}
-template<> PROTOBUF_NOINLINE ::google::protobuf::MessageOptions*
-Arena::CreateMaybeMessage< ::google::protobuf::MessageOptions >(Arena* arena) {
-  return Arena::CreateMessageInternal< ::google::protobuf::MessageOptions >(arena);
-}
-template<> PROTOBUF_NOINLINE ::google::protobuf::FieldOptions_EditionDefault*
-Arena::CreateMaybeMessage< ::google::protobuf::FieldOptions_EditionDefault >(Arena* arena) {
-  return Arena::CreateMessageInternal< ::google::protobuf::FieldOptions_EditionDefault >(arena);
-}
-template<> PROTOBUF_NOINLINE ::google::protobuf::FieldOptions*
-Arena::CreateMaybeMessage< ::google::protobuf::FieldOptions >(Arena* arena) {
-  return Arena::CreateMessageInternal< ::google::protobuf::FieldOptions >(arena);
-}
-template<> PROTOBUF_NOINLINE ::google::protobuf::OneofOptions*
-Arena::CreateMaybeMessage< ::google::protobuf::OneofOptions >(Arena* arena) {
-  return Arena::CreateMessageInternal< ::google::protobuf::OneofOptions >(arena);
-}
-template<> PROTOBUF_NOINLINE ::google::protobuf::EnumOptions*
-Arena::CreateMaybeMessage< ::google::protobuf::EnumOptions >(Arena* arena) {
-  return Arena::CreateMessageInternal< ::google::protobuf::EnumOptions >(arena);
-}
-template<> PROTOBUF_NOINLINE ::google::protobuf::EnumValueOptions*
-Arena::CreateMaybeMessage< ::google::protobuf::EnumValueOptions >(Arena* arena) {
-  return Arena::CreateMessageInternal< ::google::protobuf::EnumValueOptions >(arena);
-}
-template<> PROTOBUF_NOINLINE ::google::protobuf::ServiceOptions*
-Arena::CreateMaybeMessage< ::google::protobuf::ServiceOptions >(Arena* arena) {
-  return Arena::CreateMessageInternal< ::google::protobuf::ServiceOptions >(arena);
-}
-template<> PROTOBUF_NOINLINE ::google::protobuf::MethodOptions*
-Arena::CreateMaybeMessage< ::google::protobuf::MethodOptions >(Arena* arena) {
-  return Arena::CreateMessageInternal< ::google::protobuf::MethodOptions >(arena);
-}
-template<> PROTOBUF_NOINLINE ::google::protobuf::UninterpretedOption_NamePart*
-Arena::CreateMaybeMessage< ::google::protobuf::UninterpretedOption_NamePart >(Arena* arena) {
-  return Arena::CreateMessageInternal< ::google::protobuf::UninterpretedOption_NamePart >(arena);
-}
-template<> PROTOBUF_NOINLINE ::google::protobuf::UninterpretedOption*
-Arena::CreateMaybeMessage< ::google::protobuf::UninterpretedOption >(Arena* arena) {
-  return Arena::CreateMessageInternal< ::google::protobuf::UninterpretedOption >(arena);
-}
-template<> PROTOBUF_NOINLINE ::google::protobuf::FeatureSet*
-Arena::CreateMaybeMessage< ::google::protobuf::FeatureSet >(Arena* arena) {
-  return Arena::CreateMessageInternal< ::google::protobuf::FeatureSet >(arena);
-}
-template<> PROTOBUF_NOINLINE ::google::protobuf::SourceCodeInfo_Location*
-Arena::CreateMaybeMessage< ::google::protobuf::SourceCodeInfo_Location >(Arena* arena) {
-  return Arena::CreateMessageInternal< ::google::protobuf::SourceCodeInfo_Location >(arena);
-}
-template<> PROTOBUF_NOINLINE ::google::protobuf::SourceCodeInfo*
-Arena::CreateMaybeMessage< ::google::protobuf::SourceCodeInfo >(Arena* arena) {
-  return Arena::CreateMessageInternal< ::google::protobuf::SourceCodeInfo >(arena);
-}
-template<> PROTOBUF_NOINLINE ::google::protobuf::GeneratedCodeInfo_Annotation*
-Arena::CreateMaybeMessage< ::google::protobuf::GeneratedCodeInfo_Annotation >(Arena* arena) {
-  return Arena::CreateMessageInternal< ::google::protobuf::GeneratedCodeInfo_Annotation >(arena);
-}
-template<> PROTOBUF_NOINLINE ::google::protobuf::GeneratedCodeInfo*
-Arena::CreateMaybeMessage< ::google::protobuf::GeneratedCodeInfo >(Arena* arena) {
-  return Arena::CreateMessageInternal< ::google::protobuf::GeneratedCodeInfo >(arena);
-}
 }  // namespace protobuf
 }  // namespace google
 // @@protoc_insertion_point(global_scope)

src/google/protobuf/descriptor.pb.h

@@ -146,66 +146,6 @@ PROTOBUF_EXPORT extern UninterpretedOptionDefaultTypeInternal _UninterpretedOpti
 class UninterpretedOption_NamePart;
 struct UninterpretedOption_NamePartDefaultTypeInternal;
 PROTOBUF_EXPORT extern UninterpretedOption_NamePartDefaultTypeInternal _UninterpretedOption_NamePart_default_instance_;
-template <>
-PROTOBUF_EXPORT ::google::protobuf::DescriptorProto* Arena::CreateMaybeMessage<::google::protobuf::DescriptorProto>(Arena*);
-template <>
-PROTOBUF_EXPORT ::google::protobuf::DescriptorProto_ExtensionRange* Arena::CreateMaybeMessage<::google::protobuf::DescriptorProto_ExtensionRange>(Arena*);
-template <>
-PROTOBUF_EXPORT ::google::protobuf::DescriptorProto_ReservedRange* Arena::CreateMaybeMessage<::google::protobuf::DescriptorProto_ReservedRange>(Arena*);
-template <>
-PROTOBUF_EXPORT ::google::protobuf::EnumDescriptorProto* Arena::CreateMaybeMessage<::google::protobuf::EnumDescriptorProto>(Arena*);
-template <>
-PROTOBUF_EXPORT ::google::protobuf::EnumDescriptorProto_EnumReservedRange* Arena::CreateMaybeMessage<::google::protobuf::EnumDescriptorProto_EnumReservedRange>(Arena*);
-template <>
-PROTOBUF_EXPORT ::google::protobuf::EnumOptions* Arena::CreateMaybeMessage<::google::protobuf::EnumOptions>(Arena*);
-template <>
-PROTOBUF_EXPORT ::google::protobuf::EnumValueDescriptorProto* Arena::CreateMaybeMessage<::google::protobuf::EnumValueDescriptorProto>(Arena*);
-template <>
-PROTOBUF_EXPORT ::google::protobuf::EnumValueOptions* Arena::CreateMaybeMessage<::google::protobuf::EnumValueOptions>(Arena*);
-template <>
-PROTOBUF_EXPORT ::google::protobuf::ExtensionRangeOptions* Arena::CreateMaybeMessage<::google::protobuf::ExtensionRangeOptions>(Arena*);
-template <>
-PROTOBUF_EXPORT ::google::protobuf::ExtensionRangeOptions_Declaration* Arena::CreateMaybeMessage<::google::protobuf::ExtensionRangeOptions_Declaration>(Arena*);
-template <>
-PROTOBUF_EXPORT ::google::protobuf::FeatureSet* Arena::CreateMaybeMessage<::google::protobuf::FeatureSet>(Arena*);
-template <>
-PROTOBUF_EXPORT ::google::protobuf::FieldDescriptorProto* Arena::CreateMaybeMessage<::google::protobuf::FieldDescriptorProto>(Arena*);
-template <>
-PROTOBUF_EXPORT ::google::protobuf::FieldOptions* Arena::CreateMaybeMessage<::google::protobuf::FieldOptions>(Arena*);
-template <>
-PROTOBUF_EXPORT ::google::protobuf::FieldOptions_EditionDefault* Arena::CreateMaybeMessage<::google::protobuf::FieldOptions_EditionDefault>(Arena*);
-template <>
-PROTOBUF_EXPORT ::google::protobuf::FileDescriptorProto* Arena::CreateMaybeMessage<::google::protobuf::FileDescriptorProto>(Arena*);
-template <>
-PROTOBUF_EXPORT ::google::protobuf::FileDescriptorSet* Arena::CreateMaybeMessage<::google::protobuf::FileDescriptorSet>(Arena*);
-template <>
-PROTOBUF_EXPORT ::google::protobuf::FileOptions* Arena::CreateMaybeMessage<::google::protobuf::FileOptions>(Arena*);
-template <>
-PROTOBUF_EXPORT ::google::protobuf::GeneratedCodeInfo* Arena::CreateMaybeMessage<::google::protobuf::GeneratedCodeInfo>(Arena*);
-template <>
-PROTOBUF_EXPORT ::google::protobuf::GeneratedCodeInfo_Annotation* Arena::CreateMaybeMessage<::google::protobuf::GeneratedCodeInfo_Annotation>(Arena*);
-template <>
-PROTOBUF_EXPORT ::google::protobuf::MessageOptions* Arena::CreateMaybeMessage<::google::protobuf::MessageOptions>(Arena*);
-template <>
-PROTOBUF_EXPORT ::google::protobuf::MethodDescriptorProto* Arena::CreateMaybeMessage<::google::protobuf::MethodDescriptorProto>(Arena*);
-template <>
-PROTOBUF_EXPORT ::google::protobuf::MethodOptions* Arena::CreateMaybeMessage<::google::protobuf::MethodOptions>(Arena*);
-template <>
-PROTOBUF_EXPORT ::google::protobuf::OneofDescriptorProto* Arena::CreateMaybeMessage<::google::protobuf::OneofDescriptorProto>(Arena*);
-template <>
-PROTOBUF_EXPORT ::google::protobuf::OneofOptions* Arena::CreateMaybeMessage<::google::protobuf::OneofOptions>(Arena*);
-template <>
-PROTOBUF_EXPORT ::google::protobuf::ServiceDescriptorProto* Arena::CreateMaybeMessage<::google::protobuf::ServiceDescriptorProto>(Arena*);
-template <>
-PROTOBUF_EXPORT ::google::protobuf::ServiceOptions* Arena::CreateMaybeMessage<::google::protobuf::ServiceOptions>(Arena*);
-template <>
-PROTOBUF_EXPORT ::google::protobuf::SourceCodeInfo* Arena::CreateMaybeMessage<::google::protobuf::SourceCodeInfo>(Arena*);
-template <>
-PROTOBUF_EXPORT ::google::protobuf::SourceCodeInfo_Location* Arena::CreateMaybeMessage<::google::protobuf::SourceCodeInfo_Location>(Arena*);
-template <>
-PROTOBUF_EXPORT ::google::protobuf::UninterpretedOption* Arena::CreateMaybeMessage<::google::protobuf::UninterpretedOption>(Arena*);
-template <>
-PROTOBUF_EXPORT ::google::protobuf::UninterpretedOption_NamePart* Arena::CreateMaybeMessage<::google::protobuf::UninterpretedOption_NamePart>(Arena*);
 namespace internal {
 #if !defined(PROTOBUF_CONSTINIT_DEFAULT_INSTANCES)
 PROTOBUF_EXPORT void InitializeFileDescriptorDefaultInstancesSlow();