Improve pinning assembly when using a clang that supports it.

The new technique adds the relocation without adding an instruction that has to
be executed in the code path.

PiperOrigin-RevId: 613368436

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

@@ -87,8 +87,8 @@ std::vector<Sub> FieldVars(const FieldDescriptor* field, const Options& opts) {
       {"deprecated_attr", DeprecatedAttribute(opts, field)},
       Sub("WeakDescriptorSelfPin",
           UsingImplicitWeakDescriptor(field->file(), opts)
-              ? absl::StrCat("::", ProtobufNamespace(opts),
-                             "::internal::StrongReference(default_instance());")
+              ? absl::StrCat(
+                    StrongReferenceToType(field->containing_type(), opts), ";")
               : "")
           .WithSuffix(";"),
   };

src/google/protobuf/compiler/cpp/field_generators/message_field.cc

@@ -72,9 +72,8 @@ std::vector<Sub> Vars(const FieldDescriptor* field, const Options& opts,
       {"_weak", weak ? "_weak" : ""},
       Sub("StrongRef",
           !weak ? ""
-                : absl::Substitute("::google::protobuf::internal::StrongReference("
-                                   "reinterpret_cast<const $0&>($1));\n",
-                                   qualified_type, default_ref))
+                : absl::StrCat(
+                      StrongReferenceToType(field->message_type(), opts), ";"))
           .WithSuffix(";"),
   };
 }

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

@@ -1266,13 +1266,10 @@ void FileGenerator::GenerateReflectionInitializationCode(io::Printer* p) {
     if (UsingImplicitWeakDescriptor(file_, options_)) {
       for (auto* pinned : GetMessagesToPinGloballyForWeakDescriptors(file_)) {
         static_initializers_.push_back([this, pinned](auto* p) {
-          p->Emit(
-              {
-                  {"default", QualifiedDefaultInstanceName(pinned, options_)},
-              },
-              R"cc(
-                ::_pbi::StrongPointer(&$default$),
-              )cc");
+          p->Emit({{"pin", StrongReferenceToType(pinned, options_)}},
+                  R"cc(
+                    $pin$,
+                  )cc");
         });
       }
     }

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

@@ -1495,6 +1495,13 @@ bool UsingImplicitWeakDescriptor(const FileDescriptor* file,
          !options.opensource_runtime;
 }
 
+std::string StrongReferenceToType(const Descriptor* desc,
+                                  const Options& options) {
+  const auto name = QualifiedDefaultInstanceName(desc, options);
+  return absl::StrFormat("::%s::internal::StrongPointer<decltype(%s)*, &%s>()",
+                         ProtobufNamespace(options), name, name);
+}
+
 std::string WeakDescriptorDataSection(absl::string_view prefix,
                                       const Descriptor* descriptor,
                                       int index_in_file_messages,

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

@@ -786,7 +786,11 @@ void ListAllTypesForServices(const FileDescriptor* fd,
 bool UsingImplicitWeakDescriptor(const FileDescriptor* file,
                                  const Options& options);
 
-// Generate the section name to be used for a data object when using implicit
+// Generates a strong reference to the message in `desc`, as a statement.
+std::string StrongReferenceToType(const Descriptor* desc,
+                                  const Options& options);
+
+// Generates the section name to be used for a data object when using implicit
 // weak descriptors. The prefix determines the kind of object and the section it
 // will be merged into afterwards.
 // See `UsingImplicitWeakDescriptor` above.

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

@@ -489,8 +489,7 @@ std::vector<Sub> ClassVars(const Descriptor* desc, Options opts) {
 
       Sub("WeakDescriptorSelfPin",
           UsingImplicitWeakDescriptor(desc->file(), opts)
-              ? absl::StrCat("::", ProtobufNamespace(opts),
-                             "::internal::StrongReference(default_instance());")
+              ? absl::StrCat(StrongReferenceToType(desc, opts), ";")
               : "")
           .WithSuffix(";"),
   };
@@ -2029,6 +2028,10 @@ void MessageGenerator::GenerateClassDefinition(io::Printer* p) {
           $decl_oneof_has$;
           $decl_data$;
           $post_loop_handler$;
+
+          static constexpr const void* _raw_default_instance_ =
+              &_$classname$_default_instance_;
+
           friend class ::$proto_ns$::MessageLite;
           friend class ::$proto_ns$::Arena;
           template <typename T>
@@ -3526,9 +3529,10 @@ void MessageGenerator::GenerateClassData(io::Printer* p) {
     const auto pin_weak_descriptor = [&] {
       if (!UsingImplicitWeakDescriptor(descriptor_->file(), options_)) return;
 
-      p->Emit(R"cc(
-        ::_pbi::StrongPointer(&_$classname$_default_instance_);
-      )cc");
+      p->Emit({{"pin", StrongReferenceToType(descriptor_, options_)}},
+              R"cc(
+                $pin$;
+              )cc");
 
       // For CODE_SIZE types, we need to pin the submessages too.
       // SPEED types will pin them via the TcParse table automatically.
@@ -3536,11 +3540,11 @@ void MessageGenerator::GenerateClassData(io::Printer* p) {
       for (int i = 0; i < descriptor_->field_count(); ++i) {
         auto* field = descriptor_->field(i);
         if (field->type() != field->TYPE_MESSAGE) continue;
-        p->Emit({{"sub_default_name", QualifiedDefaultInstanceName(
-                                          field->message_type(), options_)}},
-                R"cc(
-                  ::_pbi::StrongPointer(&$sub_default_name$);
-                )cc");
+        p->Emit(
+            {{"pin", StrongReferenceToType(field->message_type(), options_)}},
+            R"cc(
+              $pin$;
+            )cc");
       }
     };
     p->Emit(

src/google/protobuf/compiler/java/java_features.pb.h

@@ -274,6 +274,10 @@ class PROTOC_EXPORT JavaFeatures final : public ::google::protobuf::Message
       1, 2, 1,
       0, 2>
       _table_;
+
+  static constexpr const void* _raw_default_instance_ =
+      &_JavaFeatures_default_instance_;
+
   friend class ::google::protobuf::MessageLite;
   friend class ::google::protobuf::Arena;
   template <typename T>

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

@@ -301,6 +301,10 @@ class PROTOC_EXPORT Version final : public ::google::protobuf::Message
       2, 4, 0,
       47, 2>
       _table_;
+
+  static constexpr const void* _raw_default_instance_ =
+      &_Version_default_instance_;
+
   friend class ::google::protobuf::MessageLite;
   friend class ::google::protobuf::Arena;
   template <typename T>
@@ -530,6 +534,10 @@ class PROTOC_EXPORT CodeGeneratorResponse_File final : public ::google::protobuf
       2, 4, 1,
       86, 2>
       _table_;
+
+  static constexpr const void* _raw_default_instance_ =
+      &_CodeGeneratorResponse_File_default_instance_;
+
   friend class ::google::protobuf::MessageLite;
   friend class ::google::protobuf::Arena;
   template <typename T>
@@ -782,6 +790,10 @@ class PROTOC_EXPORT CodeGeneratorResponse final : public ::google::protobuf::Mes
       3, 5, 1,
       60, 2>
       _table_;
+
+  static constexpr const void* _raw_default_instance_ =
+      &_CodeGeneratorResponse_default_instance_;
+
   friend class ::google::protobuf::MessageLite;
   friend class ::google::protobuf::Arena;
   template <typename T>
@@ -1041,6 +1053,10 @@ class PROTOC_EXPORT CodeGeneratorRequest final : public ::google::protobuf::Mess
       3, 5, 3,
       79, 2>
       _table_;
+
+  static constexpr const void* _raw_default_instance_ =
+      &_CodeGeneratorRequest_default_instance_;
+
   friend class ::google::protobuf::MessageLite;
   friend class ::google::protobuf::Arena;
   template <typename T>

src/google/protobuf/cpp_features.pb.h

@@ -276,6 +276,10 @@ class PROTOBUF_EXPORT CppFeatures final : public ::google::protobuf::Message
       1, 2, 1,
       0, 2>
       _table_;
+
+  static constexpr const void* _raw_default_instance_ =
+      &_CppFeatures_default_instance_;
+
   friend class ::google::protobuf::MessageLite;
   friend class ::google::protobuf::Arena;
   template <typename T>

src/google/protobuf/descriptor.pb.h

@@ -859,6 +859,10 @@ class PROTOBUF_EXPORT UninterpretedOption_NamePart final : public ::google::prot
       1, 2, 0,
       62, 2>
       _table_;
+
+  static constexpr const void* _raw_default_instance_ =
+      &_UninterpretedOption_NamePart_default_instance_;
+
   friend class ::google::protobuf::MessageLite;
   friend class ::google::protobuf::Arena;
   template <typename T>
@@ -1119,6 +1123,10 @@ class PROTOBUF_EXPORT SourceCodeInfo_Location final : public ::google::protobuf:
       3, 5, 0,
       106, 2>
       _table_;
+
+  static constexpr const void* _raw_default_instance_ =
+      &_SourceCodeInfo_Location_default_instance_;
+
   friend class ::google::protobuf::MessageLite;
   friend class ::google::protobuf::Arena;
   template <typename T>
@@ -1374,6 +1382,10 @@ class PROTOBUF_EXPORT GeneratedCodeInfo_Annotation final : public ::google::prot
       3, 5, 1,
       64, 2>
       _table_;
+
+  static constexpr const void* _raw_default_instance_ =
+      &_GeneratedCodeInfo_Annotation_default_instance_;
+
   friend class ::google::protobuf::MessageLite;
   friend class ::google::protobuf::Arena;
   template <typename T>
@@ -1565,6 +1577,10 @@ class PROTOBUF_EXPORT FieldOptions_EditionDefault final : public ::google::proto
       1, 2, 1,
       57, 2>
       _table_;
+
+  static constexpr const void* _raw_default_instance_ =
+      &_FieldOptions_EditionDefault_default_instance_;
+
   friend class ::google::protobuf::MessageLite;
   friend class ::google::protobuf::Arena;
   template <typename T>
@@ -2094,6 +2110,10 @@ class PROTOBUF_EXPORT FeatureSet final : public ::google::protobuf::Message
       3, 6, 6,
       0, 2>
       _table_;
+
+  static constexpr const void* _raw_default_instance_ =
+      &_FeatureSet_default_instance_;
+
   friend class ::google::protobuf::MessageLite;
   friend class ::google::protobuf::Arena;
   template <typename T>
@@ -2328,6 +2348,10 @@ class PROTOBUF_EXPORT ExtensionRangeOptions_Declaration final : public ::google:
       3, 5, 0,
       71, 2>
       _table_;
+
+  static constexpr const void* _raw_default_instance_ =
+      &_ExtensionRangeOptions_Declaration_default_instance_;
+
   friend class ::google::protobuf::MessageLite;
   friend class ::google::protobuf::Arena;
   template <typename T>
@@ -2512,6 +2536,10 @@ class PROTOBUF_EXPORT EnumDescriptorProto_EnumReservedRange final : public ::goo
       1, 2, 0,
       0, 2>
       _table_;
+
+  static constexpr const void* _raw_default_instance_ =
+      &_EnumDescriptorProto_EnumReservedRange_default_instance_;
+
   friend class ::google::protobuf::MessageLite;
   friend class ::google::protobuf::Arena;
   template <typename T>
@@ -2693,6 +2721,10 @@ class PROTOBUF_EXPORT DescriptorProto_ReservedRange final : public ::google::pro
       1, 2, 0,
       0, 2>
       _table_;
+
+  static constexpr const void* _raw_default_instance_ =
+      &_DescriptorProto_ReservedRange_default_instance_;
+
   friend class ::google::protobuf::MessageLite;
   friend class ::google::protobuf::Arena;
   template <typename T>
@@ -2959,6 +2991,10 @@ class PROTOBUF_EXPORT UninterpretedOption final : public ::google::protobuf::Mes
       3, 7, 1,
       75, 2>
       _table_;
+
+  static constexpr const void* _raw_default_instance_ =
+      &_UninterpretedOption_default_instance_;
+
   friend class ::google::protobuf::MessageLite;
   friend class ::google::protobuf::Arena;
   template <typename T>
@@ -3140,6 +3176,10 @@ class PROTOBUF_EXPORT SourceCodeInfo final : public ::google::protobuf::Message
       0, 1, 1,
       0, 2>
       _table_;
+
+  static constexpr const void* _raw_default_instance_ =
+      &_SourceCodeInfo_default_instance_;
+
   friend class ::google::protobuf::MessageLite;
   friend class ::google::protobuf::Arena;
   template <typename T>
@@ -3314,6 +3354,10 @@ class PROTOBUF_EXPORT GeneratedCodeInfo final : public ::google::protobuf::Messa
       0, 1, 1,
       0, 2>
       _table_;
+
+  static constexpr const void* _raw_default_instance_ =
+      &_GeneratedCodeInfo_default_instance_;
+
   friend class ::google::protobuf::MessageLite;
   friend class ::google::protobuf::Arena;
   template <typename T>
@@ -3497,6 +3541,10 @@ class PROTOBUF_EXPORT FeatureSetDefaults_FeatureSetEditionDefault final : public
       1, 2, 2,
       0, 2>
       _table_;
+
+  static constexpr const void* _raw_default_instance_ =
+      &_FeatureSetDefaults_FeatureSetEditionDefault_default_instance_;
+
   friend class ::google::protobuf::MessageLite;
   friend class ::google::protobuf::Arena;
   template <typename T>
@@ -3879,6 +3927,10 @@ class PROTOBUF_EXPORT ServiceOptions final : public ::google::protobuf::Message
       2, 3, 2,
       0, 12>
       _table_;
+
+  static constexpr const void* _raw_default_instance_ =
+      &_ServiceOptions_default_instance_;
+
   friend class ::google::protobuf::MessageLite;
   friend class ::google::protobuf::Arena;
   template <typename T>
@@ -4251,6 +4303,10 @@ class PROTOBUF_EXPORT OneofOptions final : public ::google::protobuf::Message
       2, 2, 2,
       0, 7>
       _table_;
+
+  static constexpr const void* _raw_default_instance_ =
+      &_OneofOptions_default_instance_;
+
   friend class ::google::protobuf::MessageLite;
   friend class ::google::protobuf::Arena;
   template <typename T>
@@ -4666,6 +4722,10 @@ class PROTOBUF_EXPORT MethodOptions final : public ::google::protobuf::Message
       3, 4, 3,
       0, 12>
       _table_;
+
+  static constexpr const void* _raw_default_instance_ =
+      &_MethodOptions_default_instance_;
+
   friend class ::google::protobuf::MessageLite;
   friend class ::google::protobuf::Arena;
   template <typename T>
@@ -5099,6 +5159,10 @@ class PROTOBUF_EXPORT MessageOptions final : public ::google::protobuf::Message
       3, 7, 2,
       0, 7>
       _table_;
+
+  static constexpr const void* _raw_default_instance_ =
+      &_MessageOptions_default_instance_;
+
   friend class ::google::protobuf::MessageLite;
   friend class ::google::protobuf::Arena;
   template <typename T>
@@ -5783,6 +5847,10 @@ class PROTOBUF_EXPORT FileOptions final : public ::google::protobuf::Message
       5, 21, 3,
       202, 12>
       _table_;
+
+  static constexpr const void* _raw_default_instance_ =
+      &_FileOptions_default_instance_;
+
   friend class ::google::protobuf::MessageLite;
   friend class ::google::protobuf::Arena;
   template <typename T>
@@ -6407,6 +6475,10 @@ class PROTOBUF_EXPORT FieldOptions final : public ::google::protobuf::Message
       4, 13, 7,
       0, 7>
       _table_;
+
+  static constexpr const void* _raw_default_instance_ =
+      &_FieldOptions_default_instance_;
+
   friend class ::google::protobuf::MessageLite;
   friend class ::google::protobuf::Arena;
   template <typename T>
@@ -6619,6 +6691,10 @@ class PROTOBUF_EXPORT FeatureSetDefaults final : public ::google::protobuf::Mess
       1, 3, 3,
       0, 2>
       _table_;
+
+  static constexpr const void* _raw_default_instance_ =
+      &_FeatureSetDefaults_default_instance_;
+
   friend class ::google::protobuf::MessageLite;
   friend class ::google::protobuf::Arena;
   template <typename T>
@@ -7040,6 +7116,10 @@ class PROTOBUF_EXPORT ExtensionRangeOptions final : public ::google::protobuf::M
       3, 4, 4,
       0, 12>
       _table_;
+
+  static constexpr const void* _raw_default_instance_ =
+      &_ExtensionRangeOptions_default_instance_;
+
   friend class ::google::protobuf::MessageLite;
   friend class ::google::protobuf::Arena;
   template <typename T>
@@ -7437,6 +7517,10 @@ class PROTOBUF_EXPORT EnumValueOptions final : public ::google::protobuf::Messag
       3, 4, 2,
       0, 7>
       _table_;
+
+  static constexpr const void* _raw_default_instance_ =
+      &_EnumValueOptions_default_instance_;
+
   friend class ::google::protobuf::MessageLite;
   friend class ::google::protobuf::Arena;
   template <typename T>
@@ -7846,6 +7930,10 @@ class PROTOBUF_EXPORT EnumOptions final : public ::google::protobuf::Message
       3, 5, 2,
       0, 7>
       _table_;
+
+  static constexpr const void* _raw_default_instance_ =
+      &_EnumOptions_default_instance_;
+
   friend class ::google::protobuf::MessageLite;
   friend class ::google::protobuf::Arena;
   template <typename T>
@@ -8041,6 +8129,10 @@ class PROTOBUF_EXPORT OneofDescriptorProto final : public ::google::protobuf::Me
       1, 2, 1,
       49, 2>
       _table_;
+
+  static constexpr const void* _raw_default_instance_ =
+      &_OneofDescriptorProto_default_instance_;
+
   friend class ::google::protobuf::MessageLite;
   friend class ::google::protobuf::Arena;
   template <typename T>
@@ -8292,6 +8384,10 @@ class PROTOBUF_EXPORT MethodDescriptorProto final : public ::google::protobuf::M
       3, 6, 1,
       71, 2>
       _table_;
+
+  static constexpr const void* _raw_default_instance_ =
+      &_MethodDescriptorProto_default_instance_;
+
   friend class ::google::protobuf::MessageLite;
   friend class ::google::protobuf::Arena;
   template <typename T>
@@ -8674,6 +8770,10 @@ class PROTOBUF_EXPORT FieldDescriptorProto final : public ::google::protobuf::Me
       4, 11, 3,
       96, 2>
       _table_;
+
+  static constexpr const void* _raw_default_instance_ =
+      &_FieldDescriptorProto_default_instance_;
+
   friend class ::google::protobuf::MessageLite;
   friend class ::google::protobuf::Arena;
   template <typename T>
@@ -8886,6 +8986,10 @@ class PROTOBUF_EXPORT EnumValueDescriptorProto final : public ::google::protobuf
       2, 3, 1,
       53, 2>
       _table_;
+
+  static constexpr const void* _raw_default_instance_ =
+      &_EnumValueDescriptorProto_default_instance_;
+
   friend class ::google::protobuf::MessageLite;
   friend class ::google::protobuf::Arena;
   template <typename T>
@@ -9084,6 +9188,10 @@ class PROTOBUF_EXPORT DescriptorProto_ExtensionRange final : public ::google::pr
       2, 3, 1,
       0, 2>
       _table_;
+
+  static constexpr const void* _raw_default_instance_ =
+      &_DescriptorProto_ExtensionRange_default_instance_;
+
   friend class ::google::protobuf::MessageLite;
   friend class ::google::protobuf::Arena;
   template <typename T>
@@ -9294,6 +9402,10 @@ class PROTOBUF_EXPORT ServiceDescriptorProto final : public ::google::protobuf::
       2, 3, 2,
       51, 2>
       _table_;
+
+  static constexpr const void* _raw_default_instance_ =
+      &_ServiceDescriptorProto_default_instance_;
+
   friend class ::google::protobuf::MessageLite;
   friend class ::google::protobuf::Arena;
   template <typename T>
@@ -9552,6 +9664,10 @@ class PROTOBUF_EXPORT EnumDescriptorProto final : public ::google::protobuf::Mes
       3, 5, 3,
       61, 2>
       _table_;
+
+  static constexpr const void* _raw_default_instance_ =
+      &_EnumDescriptorProto_default_instance_;
+
   friend class ::google::protobuf::MessageLite;
   friend class ::google::protobuf::Arena;
   template <typename T>
@@ -9903,6 +10019,10 @@ class PROTOBUF_EXPORT DescriptorProto final : public ::google::protobuf::Message
       4, 10, 8,
       65, 2>
       _table_;
+
+  static constexpr const void* _raw_default_instance_ =
+      &_DescriptorProto_default_instance_;
+
   friend class ::google::protobuf::MessageLite;
   friend class ::google::protobuf::Arena;
   template <typename T>
@@ -10305,6 +10425,10 @@ class PROTOBUF_EXPORT FileDescriptorProto final : public ::google::protobuf::Mes
       4, 13, 7,
       79, 2>
       _table_;
+
+  static constexpr const void* _raw_default_instance_ =
+      &_FileDescriptorProto_default_instance_;
+
   friend class ::google::protobuf::MessageLite;
   friend class ::google::protobuf::Arena;
   template <typename T>
@@ -10491,6 +10615,10 @@ class PROTOBUF_EXPORT FileDescriptorSet final : public ::google::protobuf::Messa
       0, 1, 1,
       0, 2>
       _table_;
+
+  static constexpr const void* _raw_default_instance_ =
+      &_FileDescriptorSet_default_instance_;
+
   friend class ::google::protobuf::MessageLite;
   friend class ::google::protobuf::Arena;
   template <typename T>

src/google/protobuf/generated_message_util.cc

@@ -69,7 +69,8 @@ extern const char __start_pb_defaults;
 extern const char __stop_pb_defaults;
 }
 static void InitWeakDefaults() {
-  StrongPointer(&dummy_weak_default);  // force link the dummy entry.
+  // force link the dummy entry.
+  StrongPointer<DummyWeakDefault*, &dummy_weak_default>();
   // We don't know the size of each object, but we know the layout of the tail.
   // It contains a WeakDescriptorDefaultTail object.
   // As such, we iterate the section backwards.

src/google/protobuf/message.h

@@ -1418,7 +1418,7 @@ const T* DynamicCastToGenerated(const Message* from) {
   (void)unused;
 
 #if PROTOBUF_RTTI
-  internal::StrongReference(T::default_instance());
+  internal::StrongReferenceToType<T>();
   return dynamic_cast<const T*>(from);
 #else
   bool ok = from != nullptr &&
@@ -1457,7 +1457,7 @@ T& DynamicCastToGenerated(Message& from) {
 // instance T and T is a type derived from base Message class.
 template <typename T>
 const T* DownCastToGenerated(const Message* from) {
-  internal::StrongReference(T::default_instance());
+  internal::StrongReferenceToType<T>();
   ABSL_DCHECK(DynamicCastToGenerated<T>(from) == from)
       << "Cannot downcast " << from->GetTypeName() << " to "
       << T::default_instance().GetTypeName();
@@ -1505,7 +1505,7 @@ T& DownCastToGenerated(Message& from) {
 // of loops (on x86-64 it compiles into two "mov" instructions).
 template <typename T>
 void LinkMessageReflection() {
-  internal::StrongReference(T::default_instance);
+  internal::StrongReferenceToType<T>();
 }
 
 // =============================================================================

src/google/protobuf/message_lite.h

@@ -675,6 +675,26 @@ class PROTOBUF_EXPORT MessageLite {
   void LogInitializationErrorMessage() const;
 
   bool MergeFromImpl(io::CodedInputStream* input, ParseFlags parse_flags);
+
+  template <typename T, const void* ptr = T::_raw_default_instance_>
+  static constexpr auto GetStrongPointerForTypeImpl(int) {
+    return ptr;
+  }
+  template <typename T>
+  static constexpr auto GetStrongPointerForTypeImpl(char) {
+    return &T::default_instance;
+  }
+  // Return a pointer we can use to make a strong reference to a type.
+  // Ideally, this is a pointer to the default instance.
+  // If we can't get that, then we use a pointer to the `default_instance`
+  // function. The latter always works but pins the function artificially into
+  // the binary so we avoid it.
+  template <typename T>
+  static constexpr auto GetStrongPointerForType() {
+    return GetStrongPointerForTypeImpl<T>(0);
+  }
+  template <typename T>
+  friend void internal::StrongReferenceToType();
 };
 
 namespace internal {

src/google/protobuf/port.h

@@ -39,7 +39,7 @@ class MessageLite;
 namespace internal {
 
 template <typename T>
-void StrongPointer(T* var) {
+inline PROTOBUF_ALWAYS_INLINE void StrongPointer(T* var) {
 #if defined(__GNUC__)
   asm("" : : "r"(var));
 #else
@@ -48,6 +48,32 @@ void StrongPointer(T* var) {
 #endif
 }
 
+// Similar to the overload above, but optimized for constant inputs.
+template <typename T, T ptr>
+inline PROTOBUF_ALWAYS_INLINE void StrongPointer() {
+#if defined(__x86_64__) && defined(__linux__) && !defined(__APPLE__) &&     \
+    !defined(__ANDROID__) && defined(__clang__) && __clang_major__ >= 19 && \
+    !defined(PROTOBUF_INTERNAL_TEMPORARY_STRONG_POINTER_OPT_OUT)
+  // This injects a relocation in the code path without having to run code, but
+  // we can only do it with a newer clang.
+  asm(".reloc ., BFD_RELOC_NONE, %p0" ::"Ws"(ptr));
+#else
+  StrongPointer(ptr);
+#endif
+}
+
+template <typename T>
+inline PROTOBUF_ALWAYS_INLINE void StrongReferenceToType() {
+  constexpr auto ptr = T::template GetStrongPointerForType<T>();
+#if defined(__cpp_nontype_template_args) && \
+    __cpp_nontype_template_args >= 201411L
+  // We can only use `ptr` as a template parameter since C++17
+  return StrongPointer<decltype(ptr), ptr>();
+#else
+  return StrongPointer(ptr);
+#endif
+}
+
 
 // See comments on `AllocateAtLeast` for information on size returning new.
 struct SizedPtr {