Update protobuf to 3.21.2

a628f0376085fcf46dc6d24629f2a7dacb91ae79

34 files changed, 2314 insertions, 1530 deletions

diff --git a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_helpers.h b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_helpers.h
index f7735da12f0..fe2ff1369a1 100644
--- a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_helpers.h
+++ b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_helpers.h
@@ -1,1026 +1 @@
-// Protocol Buffers - Google's data interchange format
-// Copyright 2008 Google Inc.  All rights reserved.
-// https://developers.google.com/protocol-buffers/
-//
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are
-// met:
-//
-//     * Redistributions of source code must retain the above copyright
-// notice, this list of conditions and the following disclaimer.
-//     * Redistributions in binary form must reproduce the above
-// copyright notice, this list of conditions and the following disclaimer
-// in the documentation and/or other materials provided with the
-// distribution.
-//     * Neither the name of Google Inc. nor the names of its
-// contributors may be used to endorse or promote products derived from
-// this software without specific prior written permission.
-//
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-// Author: [email protected] (Kenton Varda)
-//  Based on original Protocol Buffers design by
-//  Sanjay Ghemawat, Jeff Dean, and others.
-
-#ifndef GOOGLE_PROTOBUF_COMPILER_CPP_HELPERS_H__
-#define GOOGLE_PROTOBUF_COMPILER_CPP_HELPERS_H__
-
-#include <algorithm>
-#include <cstdint>
-#include <iterator>
-#include <map>
-#include <string>
-
-#include <google/protobuf/compiler/scc.h>
-#include <google/protobuf/compiler/code_generator.h>
-#include <google/protobuf/compiler/cpp/cpp_names.h>
-#include <google/protobuf/compiler/cpp/cpp_options.h>
-#include <google/protobuf/descriptor.pb.h>
-#include <google/protobuf/io/printer.h>
-#include <google/protobuf/descriptor.h>
-#include <google/protobuf/port.h>
-#include <google/protobuf/stubs/strutil.h>
-
-// Must be included last.
-#include <google/protobuf/port_def.inc>
-
-namespace google {
-namespace protobuf {
-namespace compiler {
-namespace cpp {
-
-enum class ArenaDtorNeeds { kNone = 0, kOnDemand = 1, kRequired = 2 };
-
-inline TProtoStringType ProtobufNamespace(const Options& /* options */) {
-  return "PROTOBUF_NAMESPACE_ID";
-}
-
-inline TProtoStringType MacroPrefix(const Options& /* options */) {
-  return "GOOGLE_PROTOBUF";
-}
-
-inline TProtoStringType DeprecatedAttribute(const Options& /* options */,
-                                       const FieldDescriptor* d) {
-  return d->options().deprecated() ? "PROTOBUF_DEPRECATED " : "";
-}
-
-inline TProtoStringType DeprecatedAttribute(const Options& /* options */,
-                                       const EnumValueDescriptor* d) {
-  return d->options().deprecated() ? "PROTOBUF_DEPRECATED_ENUM " : "";
-}
-
-// Commonly-used separator comments.  Thick is a line of '=', thin is a line
-// of '-'.
-extern const char kThickSeparator[];
-extern const char kThinSeparator[];
-
-void SetCommonVars(const Options& options,
-                   std::map<TProtoStringType, TProtoStringType>* variables);
-
-// Variables to access message data from the message scope.
-void SetCommonMessageDataVariables(
-    std::map<TProtoStringType, TProtoStringType>* variables);
-
-void SetUnknownFieldsVariable(const Descriptor* descriptor,
-                              const Options& options,
-                              std::map<TProtoStringType, TProtoStringType>* variables);
-
-bool GetBootstrapBasename(const Options& options, const TProtoStringType& basename,
-                          TProtoStringType* bootstrap_basename);
-bool MaybeBootstrap(const Options& options, GeneratorContext* generator_context,
-                    bool bootstrap_flag, TProtoStringType* basename);
-bool IsBootstrapProto(const Options& options, const FileDescriptor* file);
-
-// Name space of the proto file. This namespace is such that the string
-// "<namespace>::some_name" is the correct fully qualified namespace.
-// This means if the package is empty the namespace is "", and otherwise
-// the namespace is "::foo::bar::...::baz" without trailing semi-colons.
-TProtoStringType Namespace(const FileDescriptor* d, const Options& options);
-TProtoStringType Namespace(const Descriptor* d, const Options& options);
-TProtoStringType Namespace(const FieldDescriptor* d, const Options& options);
-TProtoStringType Namespace(const EnumDescriptor* d, const Options& options);
-
-// Returns true if it's safe to reset "field" to zero.
-bool CanInitializeByZeroing(const FieldDescriptor* field);
-
-TProtoStringType ClassName(const Descriptor* descriptor);
-TProtoStringType ClassName(const EnumDescriptor* enum_descriptor);
-
-TProtoStringType QualifiedClassName(const Descriptor* d, const Options& options);
-TProtoStringType QualifiedClassName(const EnumDescriptor* d, const Options& options);
-
-TProtoStringType QualifiedClassName(const Descriptor* d);
-TProtoStringType QualifiedClassName(const EnumDescriptor* d);
-
-// DEPRECATED just use ClassName or QualifiedClassName, a boolean is very
-// unreadable at the callsite.
-// Returns the non-nested type name for the given type.  If "qualified" is
-// true, prefix the type with the full namespace.  For example, if you had:
-//   package foo.bar;
-//   message Baz { message Qux {} }
-// Then the qualified ClassName for Qux would be:
-//   ::foo::bar::Baz_Qux
-// While the non-qualified version would be:
-//   Baz_Qux
-inline TProtoStringType ClassName(const Descriptor* descriptor, bool qualified) {
-  return qualified ? QualifiedClassName(descriptor, Options())
-                   : ClassName(descriptor);
-}
-
-inline TProtoStringType ClassName(const EnumDescriptor* descriptor, bool qualified) {
-  return qualified ? QualifiedClassName(descriptor, Options())
-                   : ClassName(descriptor);
-}
-
-// Returns the extension name prefixed with the class name if nested but without
-// the package name.
-TProtoStringType ExtensionName(const FieldDescriptor* d);
-
-TProtoStringType QualifiedExtensionName(const FieldDescriptor* d,
-                                   const Options& options);
-TProtoStringType QualifiedExtensionName(const FieldDescriptor* d);
-
-// Type name of default instance.
-TProtoStringType DefaultInstanceType(const Descriptor* descriptor,
-                                const Options& options);
-
-// Non-qualified name of the default_instance of this message.
-TProtoStringType DefaultInstanceName(const Descriptor* descriptor,
-                                const Options& options);
-
-// Non-qualified name of the default instance pointer. This is used only for
-// implicit weak fields, where we need an extra indirection.
-TProtoStringType DefaultInstancePtr(const Descriptor* descriptor,
-                               const Options& options);
-
-// Fully qualified name of the default_instance of this message.
-TProtoStringType QualifiedDefaultInstanceName(const Descriptor* descriptor,
-                                         const Options& options);
-
-// Fully qualified name of the default instance pointer.
-TProtoStringType QualifiedDefaultInstancePtr(const Descriptor* descriptor,
-                                        const Options& options);
-
-// DescriptorTable variable name.
-TProtoStringType DescriptorTableName(const FileDescriptor* file,
-                                const Options& options);
-
-// When declaring symbol externs from another file, this macro will supply the
-// dllexport needed for the target file, if any.
-TProtoStringType FileDllExport(const FileDescriptor* file, const Options& options);
-
-// Name of the base class: google::protobuf::Message or google::protobuf::MessageLite.
-TProtoStringType SuperClassName(const Descriptor* descriptor,
-                           const Options& options);
-
-// Adds an underscore if necessary to prevent conflicting with a keyword.
-TProtoStringType ResolveKeyword(const TProtoStringType& name);
-
-// Get the (unqualified) name that should be used for this field in C++ code.
-// The name is coerced to lower-case to emulate proto1 behavior.  People
-// should be using lowercase-with-underscores style for proto field names
-// anyway, so normally this just returns field->name().
-TProtoStringType FieldName(const FieldDescriptor* field);
-
-// Returns the (unqualified) private member name for this field in C++ code.
-TProtoStringType FieldMemberName(const FieldDescriptor* field);
-
-// Returns an estimate of the compiler's alignment for the field.  This
-// can't guarantee to be correct because the generated code could be compiled on
-// different systems with different alignment rules.  The estimates below assume
-// 64-bit pointers.
-int EstimateAlignmentSize(const FieldDescriptor* field);
-
-// Get the unqualified name that should be used for a field's field
-// number constant.
-TProtoStringType FieldConstantName(const FieldDescriptor* field);
-
-// Returns the scope where the field was defined (for extensions, this is
-// different from the message type to which the field applies).
-inline const Descriptor* FieldScope(const FieldDescriptor* field) {
-  return field->is_extension() ? field->extension_scope()
-                               : field->containing_type();
-}
-
-// Returns the fully-qualified type name field->message_type().  Usually this
-// is just ClassName(field->message_type(), true);
-TProtoStringType FieldMessageTypeName(const FieldDescriptor* field,
-                                 const Options& options);
-
-// Get the C++ type name for a primitive type (e.g. "double", "::google::protobuf::int32", etc.).
-const char* PrimitiveTypeName(FieldDescriptor::CppType type);
-TProtoStringType PrimitiveTypeName(const Options& options,
-                              FieldDescriptor::CppType type);
-
-// Get the declared type name in CamelCase format, as is used e.g. for the
-// methods of WireFormat.  For example, TYPE_INT32 becomes "Int32".
-const char* DeclaredTypeMethodName(FieldDescriptor::Type type);
-
-// Return the code that evaluates to the number when compiled.
-TProtoStringType Int32ToString(int number);
-
-// Get code that evaluates to the field's default value.
-TProtoStringType DefaultValue(const Options& options, const FieldDescriptor* field);
-
-// Compatibility function for callers outside proto2.
-TProtoStringType DefaultValue(const FieldDescriptor* field);
-
-// Convert a file name into a valid identifier.
-TProtoStringType FilenameIdentifier(const TProtoStringType& filename);
-
-// For each .proto file generates a unique name. To prevent collisions of
-// symbols in the global namespace
-TProtoStringType UniqueName(const TProtoStringType& name, const TProtoStringType& filename,
-                       const Options& options);
-inline TProtoStringType UniqueName(const TProtoStringType& name, const FileDescriptor* d,
-                              const Options& options) {
-  return UniqueName(name, d->name(), options);
-}
-inline TProtoStringType UniqueName(const TProtoStringType& name, const Descriptor* d,
-                              const Options& options) {
-  return UniqueName(name, d->file(), options);
-}
-inline TProtoStringType UniqueName(const TProtoStringType& name, const EnumDescriptor* d,
-                              const Options& options) {
-  return UniqueName(name, d->file(), options);
-}
-inline TProtoStringType UniqueName(const TProtoStringType& name,
-                              const ServiceDescriptor* d,
-                              const Options& options) {
-  return UniqueName(name, d->file(), options);
-}
-
-// Versions for call sites that only support the internal runtime (like proto1
-// support).
-inline Options InternalRuntimeOptions() {
-  Options options;
-  options.opensource_runtime = false;
-  return options;
-}
-inline TProtoStringType UniqueName(const TProtoStringType& name,
-                              const TProtoStringType& filename) {
-  return UniqueName(name, filename, InternalRuntimeOptions());
-}
-inline TProtoStringType UniqueName(const TProtoStringType& name,
-                              const FileDescriptor* d) {
-  return UniqueName(name, d->name(), InternalRuntimeOptions());
-}
-inline TProtoStringType UniqueName(const TProtoStringType& name, const Descriptor* d) {
-  return UniqueName(name, d->file(), InternalRuntimeOptions());
-}
-inline TProtoStringType UniqueName(const TProtoStringType& name,
-                              const EnumDescriptor* d) {
-  return UniqueName(name, d->file(), InternalRuntimeOptions());
-}
-inline TProtoStringType UniqueName(const TProtoStringType& name,
-                              const ServiceDescriptor* d) {
-  return UniqueName(name, d->file(), InternalRuntimeOptions());
-}
-
-// Return the qualified C++ name for a file level symbol.
-TProtoStringType QualifiedFileLevelSymbol(const FileDescriptor* file,
-                                     const TProtoStringType& name,
-                                     const Options& options);
-
-// Escape C++ trigraphs by escaping question marks to \?
-TProtoStringType EscapeTrigraphs(const TProtoStringType& to_escape);
-
-// Escaped function name to eliminate naming conflict.
-TProtoStringType SafeFunctionName(const Descriptor* descriptor,
-                             const FieldDescriptor* field,
-                             const TProtoStringType& prefix);
-
-// Returns true if generated messages have public unknown fields accessors
-inline bool PublicUnknownFieldsAccessors(const Descriptor* message) {
-  return message->file()->syntax() != FileDescriptor::SYNTAX_PROTO3;
-}
-
-// Returns the optimize mode for <file>, respecting <options.enforce_lite>.
-FileOptions_OptimizeMode GetOptimizeFor(const FileDescriptor* file,
-                                        const Options& options);
-
-// Determines whether unknown fields will be stored in an UnknownFieldSet or
-// a string.
-inline bool UseUnknownFieldSet(const FileDescriptor* file,
-                               const Options& options) {
-  return GetOptimizeFor(file, options) != FileOptions::LITE_RUNTIME;
-}
-
-inline bool IsWeak(const FieldDescriptor* field, const Options& options) {
-  if (field->options().weak()) {
-    GOOGLE_CHECK(!options.opensource_runtime);
-    return true;
-  }
-  return false;
-}
-
-bool IsStringInlined(const FieldDescriptor* descriptor, const Options& options);
-
-// For a string field, returns the effective ctype.  If the actual ctype is
-// not supported, returns the default of STRING.
-FieldOptions::CType EffectiveStringCType(const FieldDescriptor* field,
-                                         const Options& options);
-
-inline bool IsCord(const FieldDescriptor* field, const Options& options) {
-  return field->cpp_type() == FieldDescriptor::CPPTYPE_STRING &&
-         EffectiveStringCType(field, options) == FieldOptions::CORD;
-}
-
-inline bool IsString(const FieldDescriptor* field, const Options& options) {
-  return field->cpp_type() == FieldDescriptor::CPPTYPE_STRING &&
-         EffectiveStringCType(field, options) == FieldOptions::STRING;
-}
-
-inline bool IsStringPiece(const FieldDescriptor* field,
-                          const Options& options) {
-  return field->cpp_type() == FieldDescriptor::CPPTYPE_STRING &&
-         EffectiveStringCType(field, options) == FieldOptions::STRING_PIECE;
-}
-
-class MessageSCCAnalyzer;
-
-// Does the given FileDescriptor use lazy fields?
-bool HasLazyFields(const FileDescriptor* file, const Options& options,
-                   MessageSCCAnalyzer* scc_analyzer);
-
-// Is the given field a supported lazy field?
-bool IsLazy(const FieldDescriptor* field, const Options& options,
-            MessageSCCAnalyzer* scc_analyzer);
-
-// Is this an explicit (non-profile driven) lazy field, as denoted by
-// lazy/unverified_lazy in the descriptor?
-inline bool IsExplicitLazy(const FieldDescriptor* field) {
-  return field->options().lazy() || field->options().unverified_lazy();
-}
-
-inline bool IsLazilyVerifiedLazy(const FieldDescriptor* field,
-                                 const Options& options) {
-  // TODO(b/211906113): Make lazy() imply eagerly verified lazy.
-  return IsExplicitLazy(field) && !field->is_repeated() &&
-         field->type() == FieldDescriptor::TYPE_MESSAGE &&
-         GetOptimizeFor(field->file(), options) != FileOptions::LITE_RUNTIME &&
-         !options.opensource_runtime;
-}
-
-inline bool IsEagerlyVerifiedLazy(const FieldDescriptor* field,
-                                  const Options& options,
-                                  MessageSCCAnalyzer* scc_analyzer) {
-  // TODO(b/211906113): Make lazy() imply eagerly verified lazy.
-  return IsLazy(field, options, scc_analyzer) && !IsExplicitLazy(field);
-}
-
-inline bool IsFieldUsed(const FieldDescriptor* /* field */,
-                        const Options& /* options */) {
-  return true;
-}
-
-// Returns true if "field" is stripped.
-inline bool IsFieldStripped(const FieldDescriptor* /*field*/,
-                            const Options& /*options*/) {
-  return false;
-}
-
-// Does the file contain any definitions that need extension_set.h?
-bool HasExtensionsOrExtendableMessage(const FileDescriptor* file);
-
-// Does the file have any repeated fields, necessitating the file to include
-// repeated_field.h? This does not include repeated extensions, since those are
-// all stored internally in an ExtensionSet, not a separate RepeatedField*.
-bool HasRepeatedFields(const FileDescriptor* file);
-
-// Does the file have any string/bytes fields with ctype=STRING_PIECE? This
-// does not include extensions, since ctype is ignored for extensions.
-bool HasStringPieceFields(const FileDescriptor* file, const Options& options);
-
-// Does the file have any string/bytes fields with ctype=CORD? This does not
-// include extensions, since ctype is ignored for extensions.
-bool HasCordFields(const FileDescriptor* file, const Options& options);
-
-// Does the file have any map fields, necessitating the file to include
-// map_field_inl.h and map.h.
-bool HasMapFields(const FileDescriptor* file);
-
-// Does this file have any enum type definitions?
-bool HasEnumDefinitions(const FileDescriptor* file);
-
-// Does this file have generated parsing, serialization, and other
-// standard methods for which reflection-based fallback implementations exist?
-inline bool HasGeneratedMethods(const FileDescriptor* file,
-                                const Options& options) {
-  return GetOptimizeFor(file, options) != FileOptions::CODE_SIZE;
-}
-
-// Do message classes in this file have descriptor and reflection methods?
-inline bool HasDescriptorMethods(const FileDescriptor* file,
-                                 const Options& options) {
-  return GetOptimizeFor(file, options) != FileOptions::LITE_RUNTIME;
-}
-
-// Should we generate generic services for this file?
-inline bool HasGenericServices(const FileDescriptor* file,
-                               const Options& options) {
-  return file->service_count() > 0 &&
-         GetOptimizeFor(file, options) != FileOptions::LITE_RUNTIME &&
-         file->options().cc_generic_services();
-}
-
-inline bool IsProto2MessageSet(const Descriptor* descriptor,
-                               const Options& options) {
-  return !options.opensource_runtime &&
-         options.enforce_mode != EnforceOptimizeMode::kLiteRuntime &&
-         !options.lite_implicit_weak_fields &&
-         descriptor->options().message_set_wire_format() &&
-         descriptor->full_name() == "google.protobuf.bridge.MessageSet";
-}
-
-inline bool IsMapEntryMessage(const Descriptor* descriptor) {
-  return descriptor->options().map_entry();
-}
-
-// Returns true if the field's CPPTYPE is string or message.
-bool IsStringOrMessage(const FieldDescriptor* field);
-
-TProtoStringType UnderscoresToCamelCase(const TProtoStringType& input,
-                                   bool cap_next_letter);
-
-inline bool IsProto3(const FileDescriptor* file) {
-  return file->syntax() == FileDescriptor::SYNTAX_PROTO3;
-}
-
-inline bool HasHasbit(const FieldDescriptor* field) {
-  // This predicate includes proto3 message fields only if they have "optional".
-  //   Foo submsg1 = 1;           // HasHasbit() == false
-  //   optional Foo submsg2 = 2;  // HasHasbit() == true
-  // This is slightly odd, as adding "optional" to a singular proto3 field does
-  // not change the semantics or API. However whenever any field in a message
-  // has a hasbit, it forces reflection to include hasbit offsets for *all*
-  // fields, even if almost all of them are set to -1 (no hasbit). So to avoid
-  // causing a sudden size regression for ~all proto3 messages, we give proto3
-  // message fields a hasbit only if "optional" is present. If the user is
-  // explicitly writing "optional", it is likely they are writing it on
-  // primitive fields also.
-  return (field->has_optional_keyword() || field->is_required()) &&
-         !field->options().weak();
-}
-
-// Returns true if 'enum' semantics are such that unknown values are preserved
-// in the enum field itself, rather than going to the UnknownFieldSet.
-inline bool HasPreservingUnknownEnumSemantics(const FieldDescriptor* field) {
-  return field->file()->syntax() == FileDescriptor::SYNTAX_PROTO3;
-}
-
-inline bool IsCrossFileMessage(const FieldDescriptor* field) {
-  return field->type() == FieldDescriptor::TYPE_MESSAGE &&
-         field->message_type()->file() != field->file();
-}
-
-inline TProtoStringType MakeDefaultName(const FieldDescriptor* field) {
-  return "_i_give_permission_to_break_this_code_default_" + FieldName(field) +
-         "_";
-}
-
-// Semantically distinct from MakeDefaultName in that it gives the C++ code
-// referencing a default field from the message scope, rather than just the
-// variable name.
-// For example, declarations of default variables should always use just
-// MakeDefaultName to produce code like:
-//   Type _i_give_permission_to_break_this_code_default_field_;
-//
-// Code that references these should use MakeDefaultFieldName, in case the field
-// exists at some nested level like:
-//   internal_container_._i_give_permission_to_break_this_code_default_field_;
-inline TProtoStringType MakeDefaultFieldName(const FieldDescriptor* field) {
-  return MakeDefaultName(field);
-}
-
-inline TProtoStringType MakeVarintCachedSizeName(const FieldDescriptor* field) {
-  return StrCat("_", FieldName(field), "_cached_byte_size_");
-}
-
-// Semantically distinct from MakeVarintCachedSizeName in that it gives the C++
-// code referencing the object from the message scope, rather than just the
-// variable name.
-// For example, declarations of default variables should always use just
-// MakeVarintCachedSizeName to produce code like:
-//   Type _field_cached_byte_size_;
-//
-// Code that references these variables should use
-// MakeVarintCachedSizeFieldName, in case the field exists at some nested level
-// like:
-//   internal_container_._field_cached_byte_size_;
-inline TProtoStringType MakeVarintCachedSizeFieldName(const FieldDescriptor* field) {
-  return StrCat("_", FieldName(field), "_cached_byte_size_");
-}
-
-// Note: A lot of libraries detect Any protos based on Descriptor::full_name()
-// while the two functions below use FileDescriptor::name(). In a sane world the
-// two approaches should be equivalent. But if you are dealing with descriptors
-// from untrusted sources, you might need to match semantics across libraries.
-bool IsAnyMessage(const FileDescriptor* descriptor, const Options& options);
-bool IsAnyMessage(const Descriptor* descriptor, const Options& options);
-
-bool IsWellKnownMessage(const FileDescriptor* descriptor);
-
-inline TProtoStringType IncludeGuard(const FileDescriptor* file, bool pb_h,
-                                bool deps,
-                                const Options& options) {
-  // If we are generating a .pb.h file and the proto_h option is enabled, then
-  // the .pb.h gets an extra suffix.
-  TProtoStringType filename_identifier = FilenameIdentifier(
-      file->name() + (deps ? ".deps": "") + (pb_h && options.proto_h ? ".pb.h" : ""));
-
-  if (IsWellKnownMessage(file)) {
-    // For well-known messages we need third_party/protobuf and net/proto2 to
-    // have distinct include guards, because some source files include both and
-    // both need to be defined (the third_party copies will be in the
-    // google::protobuf_opensource namespace).
-    return MacroPrefix(options) + "_INCLUDED_" + filename_identifier;
-  } else {
-    // Ideally this case would use distinct include guards for opensource and
-    // google3 protos also.  (The behavior of "first #included wins" is not
-    // ideal).  But unfortunately some legacy code includes both and depends on
-    // the identical include guards to avoid compile errors.
-    //
-    // We should clean this up so that this case can be removed.
-    return "GOOGLE_PROTOBUF_INCLUDED_" + filename_identifier;
-  }
-}
-
-// Returns the OptimizeMode for this file, furthermore it updates a status
-// bool if has_opt_codesize_extension is non-null. If this status bool is true
-// it means this file contains an extension that itself is defined as
-// optimized_for = CODE_SIZE.
-FileOptions_OptimizeMode GetOptimizeFor(const FileDescriptor* file,
-                                        const Options& options,
-                                        bool* has_opt_codesize_extension);
-inline FileOptions_OptimizeMode GetOptimizeFor(const FileDescriptor* file,
-                                               const Options& options) {
-  return GetOptimizeFor(file, options, nullptr);
-}
-inline bool NeedsEagerDescriptorAssignment(const FileDescriptor* file,
-                                           const Options& options) {
-  bool has_opt_codesize_extension;
-  if (GetOptimizeFor(file, options, &has_opt_codesize_extension) ==
-          FileOptions::CODE_SIZE &&
-      has_opt_codesize_extension) {
-    // If this filedescriptor contains an extension from another file which
-    // is optimized_for = CODE_SIZE. We need to be careful in the ordering so
-    // we eagerly build the descriptors in the dependencies before building
-    // the descriptors of this file.
-    return true;
-  } else {
-    // If we have a generated code based parser we never need eager
-    // initialization of descriptors of our deps.
-    return false;
-  }
-}
-
-// This orders the messages in a .pb.cc as it's outputted by file.cc
-void FlattenMessagesInFile(const FileDescriptor* file,
-                           std::vector<const Descriptor*>* result);
-inline std::vector<const Descriptor*> FlattenMessagesInFile(
-    const FileDescriptor* file) {
-  std::vector<const Descriptor*> result;
-  FlattenMessagesInFile(file, &result);
-  return result;
-}
-
-template <typename F>
-void ForEachMessage(const Descriptor* descriptor, F&& func) {
-  for (int i = 0; i < descriptor->nested_type_count(); i++)
-    ForEachMessage(descriptor->nested_type(i), std::forward<F&&>(func));
-  func(descriptor);
-}
-
-template <typename F>
-void ForEachMessage(const FileDescriptor* descriptor, F&& func) {
-  for (int i = 0; i < descriptor->message_type_count(); i++)
-    ForEachMessage(descriptor->message_type(i), std::forward<F&&>(func));
-}
-
-bool HasWeakFields(const Descriptor* desc, const Options& options);
-bool HasWeakFields(const FileDescriptor* desc, const Options& options);
-
-// Returns true if the "required" restriction check should be ignored for the
-// given field.
-inline static bool ShouldIgnoreRequiredFieldCheck(const FieldDescriptor* field,
-                                                  const Options& options) {
-  // Do not check "required" for lazily verified lazy fields.
-  return IsLazilyVerifiedLazy(field, options);
-}
-
-struct MessageAnalysis {
-  bool is_recursive = false;
-  bool contains_cord = false;
-  bool contains_extension = false;
-  bool contains_required = false;
-  bool contains_weak = false;  // Implicit weak as well.
-};
-
-// This class is used in FileGenerator, to ensure linear instead of
-// quadratic performance, if we do this per message we would get O(V*(V+E)).
-// Logically this is just only used in message.cc, but in the header for
-// FileGenerator to help share it.
-class PROTOC_EXPORT MessageSCCAnalyzer {
- public:
-  explicit MessageSCCAnalyzer(const Options& options) : options_(options) {}
-
-  MessageAnalysis GetSCCAnalysis(const SCC* scc);
-
-  bool HasRequiredFields(const Descriptor* descriptor) {
-    MessageAnalysis result = GetSCCAnalysis(GetSCC(descriptor));
-    return result.contains_required || result.contains_extension;
-  }
-  bool HasWeakField(const Descriptor* descriptor) {
-    MessageAnalysis result = GetSCCAnalysis(GetSCC(descriptor));
-    return result.contains_weak;
-  }
-  const SCC* GetSCC(const Descriptor* descriptor) {
-    return analyzer_.GetSCC(descriptor);
-  }
-
- private:
-  struct DepsGenerator {
-    std::vector<const Descriptor*> operator()(const Descriptor* desc) const {
-      std::vector<const Descriptor*> deps;
-      for (int i = 0; i < desc->field_count(); i++) {
-        if (desc->field(i)->message_type()) {
-          deps.push_back(desc->field(i)->message_type());
-        }
-      }
-      return deps;
-    }
-  };
-  SCCAnalyzer<DepsGenerator> analyzer_;
-  Options options_;
-  std::map<const SCC*, MessageAnalysis> analysis_cache_;
-};
-
-void ListAllFields(const Descriptor* d,
-                   std::vector<const FieldDescriptor*>* fields);
-void ListAllFields(const FileDescriptor* d,
-                   std::vector<const FieldDescriptor*>* fields);
-
-template <class T>
-void ForEachField(const Descriptor* d, T&& func) {
-  for (int i = 0; i < d->nested_type_count(); i++) {
-    ForEachField(d->nested_type(i), std::forward<T&&>(func));
-  }
-  for (int i = 0; i < d->extension_count(); i++) {
-    func(d->extension(i));
-  }
-  for (int i = 0; i < d->field_count(); i++) {
-    func(d->field(i));
-  }
-}
-
-template <class T>
-void ForEachField(const FileDescriptor* d, T&& func) {
-  for (int i = 0; i < d->message_type_count(); i++) {
-    ForEachField(d->message_type(i), std::forward<T&&>(func));
-  }
-  for (int i = 0; i < d->extension_count(); i++) {
-    func(d->extension(i));
-  }
-}
-
-void ListAllTypesForServices(const FileDescriptor* fd,
-                             std::vector<const Descriptor*>* types);
-
-// Indicates whether we should use implicit weak fields for this file.
-bool UsingImplicitWeakFields(const FileDescriptor* file,
-                             const Options& options);
-
-// Indicates whether to treat this field as implicitly weak.
-bool IsImplicitWeakField(const FieldDescriptor* field, const Options& options,
-                         MessageSCCAnalyzer* scc_analyzer);
-
-inline bool HasSimpleBaseClass(const Descriptor* desc, const Options& options) {
-  if (!HasDescriptorMethods(desc->file(), options)) return false;
-  if (desc->extension_range_count() != 0) return false;
-  if (desc->field_count() == 0) return true;
-  // TODO(jorg): Support additional common message types with only one
-  // or two fields
-  return false;
-}
-
-inline bool HasSimpleBaseClasses(const FileDescriptor* file,
-                                 const Options& options) {
-  bool v = false;
-  ForEachMessage(file, [&v, &options](const Descriptor* desc) {
-    v |= HasSimpleBaseClass(desc, options);
-  });
-  return v;
-}
-
-inline TProtoStringType SimpleBaseClass(const Descriptor* desc,
-                                   const Options& options) {
-  if (!HasDescriptorMethods(desc->file(), options)) return "";
-  if (desc->extension_range_count() != 0) return "";
-  if (desc->field_count() == 0) {
-    return "ZeroFieldsBase";
-  }
-  // TODO(jorg): Support additional common message types with only one
-  // or two fields
-  return "";
-}
-
-// Formatter is a functor class which acts as a closure around printer and
-// the variable map. It's much like printer->Print except it supports both named
-// variables that are substituted using a key value map and direct arguments. In
-// the format string $1$, $2$, etc... are substituted for the first, second, ...
-// direct argument respectively in the format call, it accepts both strings and
-// integers. The implementation verifies all arguments are used and are "first"
-// used in order of appearance in the argument list. For example,
-//
-// Format("return array[$1$];", 3) -> "return array[3];"
-// Format("array[$2$] = $1$;", "Bla", 3) -> FATAL error (wrong order)
-// Format("array[$1$] = $2$;", 3, "Bla") -> "array[3] = Bla;"
-//
-// The arguments can be used more than once like
-//
-// Format("array[$1$] = $2$;  // Index = $1$", 3, "Bla") ->
-//        "array[3] = Bla;  // Index = 3"
-//
-// If you use more arguments use the following style to help the reader,
-//
-// Format("int $1$() {\n"
-//        "  array[$2$] = $3$;\n"
-//        "  return $4$;"
-//        "}\n",
-//        funname, // 1
-//        idx,  // 2
-//        varname,  // 3
-//        retval);  // 4
-//
-// but consider using named variables. Named variables like $foo$, with some
-// identifier foo, are looked up in the map. One additional feature is that
-// spaces are accepted between the '$' delimiters, $ foo$ will
-// substiture to " bar" if foo stands for "bar", but in case it's empty
-// will substitute to "". Hence, for example,
-//
-// Format(vars, "$dllexport $void fun();") -> "void fun();"
-//                                            "__declspec(export) void fun();"
-//
-// which is convenient to prevent double, leading or trailing spaces.
-class PROTOC_EXPORT Formatter {
- public:
-  explicit Formatter(io::Printer* printer) : printer_(printer) {}
-  Formatter(io::Printer* printer,
-            const std::map<TProtoStringType, TProtoStringType>& vars)
-      : printer_(printer), vars_(vars) {}
-
-  template <typename T>
-  void Set(const TProtoStringType& key, const T& value) {
-    vars_[key] = ToString(value);
-  }
-
-  void AddMap(const std::map<TProtoStringType, TProtoStringType>& vars) {
-    for (const auto& keyval : vars) vars_[keyval.first] = keyval.second;
-  }
-
-  template <typename... Args>
-  void operator()(const char* format, const Args&... args) const {
-    printer_->FormatInternal({ToString(args)...}, vars_, format);
-  }
-
-  void Indent() const { printer_->Indent(); }
-  void Outdent() const { printer_->Outdent(); }
-  io::Printer* printer() const { return printer_; }
-
-  class PROTOC_EXPORT ScopedIndenter {
-   public:
-    explicit ScopedIndenter(Formatter* format) : format_(format) {
-      format_->Indent();
-    }
-    ~ScopedIndenter() { format_->Outdent(); }
-
-   private:
-    Formatter* format_;
-  };
-
-  PROTOBUF_NODISCARD ScopedIndenter ScopedIndent() {
-    return ScopedIndenter(this);
-  }
-  template <typename... Args>
-  PROTOBUF_NODISCARD ScopedIndenter ScopedIndent(const char* format,
-                                                 const Args&&... args) {
-    (*this)(format, static_cast<Args&&>(args)...);
-    return ScopedIndenter(this);
-  }
-
-  class PROTOC_EXPORT SaveState {
-   public:
-    explicit SaveState(Formatter* format)
-        : format_(format), vars_(format->vars_) {}
-    ~SaveState() { format_->vars_.swap(vars_); }
-
-   private:
-    Formatter* format_;
-    std::map<TProtoStringType, TProtoStringType> vars_;
-  };
-
- private:
-  io::Printer* printer_;
-  std::map<TProtoStringType, TProtoStringType> vars_;
-
-  // Convenience overloads to accept different types as arguments.
-  static TProtoStringType ToString(const TProtoStringType& s) { return s; }
-  template <typename I, typename = typename std::enable_if<
-                            std::is_integral<I>::value>::type>
-  static TProtoStringType ToString(I x) {
-    return StrCat(x);
-  }
-  static TProtoStringType ToString(strings::Hex x) { return StrCat(x); }
-  static TProtoStringType ToString(const FieldDescriptor* d) { return Payload(d); }
-  static TProtoStringType ToString(const Descriptor* d) { return Payload(d); }
-  static TProtoStringType ToString(const EnumDescriptor* d) { return Payload(d); }
-  static TProtoStringType ToString(const EnumValueDescriptor* d) {
-    return Payload(d);
-  }
-  static TProtoStringType ToString(const OneofDescriptor* d) { return Payload(d); }
-
-  template <typename Descriptor>
-  static TProtoStringType Payload(const Descriptor* descriptor) {
-    std::vector<int> path;
-    descriptor->GetLocationPath(&path);
-    GeneratedCodeInfo::Annotation annotation;
-    for (int index : path) {
-      annotation.add_path(index);
-    }
-    annotation.set_source_file(descriptor->file()->name());
-    return annotation.SerializeAsString();
-  }
-};
-
-template <class T>
-void PrintFieldComment(const Formatter& format, const T* field) {
-  // Print the field's (or oneof's) proto-syntax definition as a comment.
-  // We don't want to print group bodies so we cut off after the first
-  // line.
-  DebugStringOptions options;
-  options.elide_group_body = true;
-  options.elide_oneof_body = true;
-  TProtoStringType def = field->DebugStringWithOptions(options);
-  format("// $1$\n", def.substr(0, def.find_first_of('\n')));
-}
-
-class PROTOC_EXPORT NamespaceOpener {
- public:
-  explicit NamespaceOpener(const Formatter& format)
-      : printer_(format.printer()) {}
-  NamespaceOpener(const TProtoStringType& name, const Formatter& format)
-      : NamespaceOpener(format) {
-    ChangeTo(name);
-  }
-  ~NamespaceOpener() { ChangeTo(""); }
-
-  void ChangeTo(const TProtoStringType& name) {
-    std::vector<TProtoStringType> new_stack_ =
-        Split(name, "::", true);
-    size_t len = std::min(name_stack_.size(), new_stack_.size());
-    size_t common_idx = 0;
-    while (common_idx < len) {
-      if (name_stack_[common_idx] != new_stack_[common_idx]) break;
-      common_idx++;
-    }
-    for (auto it = name_stack_.crbegin();
-         it != name_stack_.crend() - common_idx; ++it) {
-      if (*it == "PROTOBUF_NAMESPACE_ID") {
-        printer_->Print("PROTOBUF_NAMESPACE_CLOSE\n");
-      } else {
-        printer_->Print("}  // namespace $ns$\n", "ns", *it);
-      }
-    }
-    name_stack_.swap(new_stack_);
-    for (size_t i = common_idx; i < name_stack_.size(); ++i) {
-      if (name_stack_[i] == "PROTOBUF_NAMESPACE_ID") {
-        printer_->Print("PROTOBUF_NAMESPACE_OPEN\n");
-      } else {
-        printer_->Print("namespace $ns$ {\n", "ns", name_stack_[i]);
-      }
-    }
-  }
-
- private:
-  io::Printer* printer_;
-  std::vector<TProtoStringType> name_stack_;
-};
-
-enum class Utf8CheckMode {
-  kStrict = 0,  // Parsing will fail if non UTF-8 data is in string fields.
-  kVerify = 1,  // Only log an error but parsing will succeed.
-  kNone = 2,    // No UTF-8 check.
-};
-
-Utf8CheckMode GetUtf8CheckMode(const FieldDescriptor* field,
-                               const Options& options);
-
-void GenerateUtf8CheckCodeForString(const FieldDescriptor* field,
-                                    const Options& options, bool for_parse,
-                                    const char* parameters,
-                                    const Formatter& format);
-
-void GenerateUtf8CheckCodeForCord(const FieldDescriptor* field,
-                                  const Options& options, bool for_parse,
-                                  const char* parameters,
-                                  const Formatter& format);
-
-template <typename T>
-struct FieldRangeImpl {
-  struct Iterator {
-    using iterator_category = std::forward_iterator_tag;
-    using value_type = const FieldDescriptor*;
-    using difference_type = int;
-
-    value_type operator*() { return descriptor->field(idx); }
-
-    friend bool operator==(const Iterator& a, const Iterator& b) {
-      GOOGLE_DCHECK(a.descriptor == b.descriptor);
-      return a.idx == b.idx;
-    }
-    friend bool operator!=(const Iterator& a, const Iterator& b) {
-      return !(a == b);
-    }
-
-    Iterator& operator++() {
-      idx++;
-      return *this;
-    }
-
-    int idx;
-    const T* descriptor;
-  };
-
-  Iterator begin() const { return {0, descriptor}; }
-  Iterator end() const { return {descriptor->field_count(), descriptor}; }
-
-  const T* descriptor;
-};
-
-template <typename T>
-FieldRangeImpl<T> FieldRange(const T* desc) {
-  return {desc};
-}
-
-struct OneOfRangeImpl {
-  struct Iterator {
-    using iterator_category = std::forward_iterator_tag;
-    using value_type = const OneofDescriptor*;
-    using difference_type = int;
-
-    value_type operator*() { return descriptor->oneof_decl(idx); }
-
-    friend bool operator==(const Iterator& a, const Iterator& b) {
-      GOOGLE_DCHECK(a.descriptor == b.descriptor);
-      return a.idx == b.idx;
-    }
-    friend bool operator!=(const Iterator& a, const Iterator& b) {
-      return !(a == b);
-    }
-
-    Iterator& operator++() {
-      idx++;
-      return *this;
-    }
-
-    int idx;
-    const Descriptor* descriptor;
-  };
-
-  Iterator begin() const { return {0, descriptor}; }
-  Iterator end() const {
-    return {descriptor->real_oneof_decl_count(), descriptor};
-  }
-
-  const Descriptor* descriptor;
-};
-
-inline OneOfRangeImpl OneOfRange(const Descriptor* desc) { return {desc}; }
-
-PROTOC_EXPORT TProtoStringType StripProto(const TProtoStringType& filename);
-
-bool EnableMessageOwnedArena(const Descriptor* desc, const Options& options);
-
-bool ShouldVerify(const Descriptor* descriptor, const Options& options,
-                  MessageSCCAnalyzer* scc_analyzer);
-bool ShouldVerify(const FileDescriptor* file, const Options& options,
-                  MessageSCCAnalyzer* scc_analyzer);
-}  // namespace cpp
-}  // namespace compiler
-}  // namespace protobuf
-}  // namespace google
-
-#include <google/protobuf/port_undef.inc>
-
-#endif  // GOOGLE_PROTOBUF_COMPILER_CPP_HELPERS_H__
+#include "helpers.h"
\ No newline at end of file
diff --git a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_enum.cc b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/enum.cc
index 960dfcadf79..91d0b9442b7 100644
--- a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_enum.cc
+++ b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/enum.cc
@@ -32,7 +32,7 @@
 //  Based on original Protocol Buffers design by
 //  Sanjay Ghemawat, Jeff Dean, and others.
 
-#include <google/protobuf/compiler/cpp/cpp_enum.h>
+#include <google/protobuf/compiler/cpp/enum.h>
 
 #include <cstdint>
 #include <limits>
@@ -40,8 +40,8 @@
 
 #include <google/protobuf/io/printer.h>
 #include <google/protobuf/stubs/strutil.h>
-#include <google/protobuf/compiler/cpp/cpp_helpers.h>
-#include <google/protobuf/compiler/cpp/cpp_names.h>
+#include <google/protobuf/compiler/cpp/helpers.h>
+#include <google/protobuf/compiler/cpp/names.h>
 
 namespace google {
 namespace protobuf {
diff --git a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_enum.h b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/enum.h
index 652a26b6db8..550f43b1ed4 100644
--- a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_enum.h
+++ b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/enum.h
@@ -40,7 +40,7 @@
 #include <string>
 
 #include <google/protobuf/descriptor.h>
-#include <google/protobuf/compiler/cpp/cpp_options.h>
+#include <google/protobuf/compiler/cpp/options.h>
 
 namespace google {
 namespace protobuf {
diff --git a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_enum_field.cc b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/enum_field.cc
index f50fca4926a..dc8dc524815 100644
--- a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_enum_field.cc
+++ b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/enum_field.cc
@@ -32,12 +32,13 @@
 //  Based on original Protocol Buffers design by
 //  Sanjay Ghemawat, Jeff Dean, and others.
 
-#include <google/protobuf/compiler/cpp/cpp_enum_field.h>
+#include <google/protobuf/compiler/cpp/enum_field.h>
 
 #include <google/protobuf/io/printer.h>
 #include <google/protobuf/wire_format.h>
 #include <google/protobuf/stubs/strutil.h>
-#include <google/protobuf/compiler/cpp/cpp_helpers.h>
+#include <google/protobuf/compiler/cpp/field.h>
+#include <google/protobuf/compiler/cpp/helpers.h>
 
 namespace google {
 namespace protobuf {
@@ -55,8 +56,9 @@ void SetEnumVariables(const FieldDescriptor* descriptor,
   (*variables)["default"] = Int32ToString(default_value->number());
   (*variables)["full_name"] = descriptor->full_name();
   (*variables)["cached_byte_size_name"] = MakeVarintCachedSizeName(descriptor);
+  bool cold = ShouldSplit(descriptor, options);
   (*variables)["cached_byte_size_field"] =
-      MakeVarintCachedSizeFieldName(descriptor);
+      MakeVarintCachedSizeFieldName(descriptor, cold);
 }
 
 }  // namespace
@@ -110,6 +112,7 @@ void EnumFieldGenerator::GenerateInlineAccessorDefinitions(
       "  $field$ = value;\n"
       "}\n"
       "inline void $classname$::set_$name$($type$ value) {\n"
+      "$maybe_prepare_split_message$"
       "  _internal_set_$name$(value);\n"
       "$annotate_set$"
       "  // @@protoc_insertion_point(field_set:$full_name$)\n"
@@ -123,7 +126,7 @@ void EnumFieldGenerator::GenerateClearingCode(io::Printer* printer) const {
 
 void EnumFieldGenerator::GenerateMergingCode(io::Printer* printer) const {
   Formatter format(printer, variables_);
-  format("_internal_set_$name$(from._internal_$name$());\n");
+  format("_this->_internal_set_$name$(from._internal_$name$());\n");
 }
 
 void EnumFieldGenerator::GenerateSwappingCode(io::Printer* printer) const {
@@ -131,15 +134,10 @@ void EnumFieldGenerator::GenerateSwappingCode(io::Printer* printer) const {
   format("swap($field$, other->$field$);\n");
 }
 
-void EnumFieldGenerator::GenerateConstructorCode(io::Printer* printer) const {
-  Formatter format(printer, variables_);
-  format("$field$ = $default$;\n");
-}
-
 void EnumFieldGenerator::GenerateCopyConstructorCode(
     io::Printer* printer) const {
   Formatter format(printer, variables_);
-  format("$field$ = from.$field$;\n");
+  format("_this->$field$ = from.$field$;\n");
 }
 
 void EnumFieldGenerator::GenerateSerializeWithCachedSizesToArray(
@@ -158,10 +156,26 @@ void EnumFieldGenerator::GenerateByteSize(io::Printer* printer) const {
       "  ::_pbi::WireFormatLite::EnumSize(this->_internal_$name$());\n");
 }
 
-void EnumFieldGenerator::GenerateConstinitInitializer(
+void EnumFieldGenerator::GenerateConstexprAggregateInitializer(
+    io::Printer* printer) const {
+  Formatter format(printer, variables_);
+  format("/*decltype($field$)*/$default$");
+}
+
+void EnumFieldGenerator::GenerateAggregateInitializer(
     io::Printer* printer) const {
   Formatter format(printer, variables_);
-  format("$name$_($default$)\n");
+  if (ShouldSplit(descriptor_, options_)) {
+    format("decltype(Impl_::Split::$name$_){$default$}");
+    return;
+  }
+  format("decltype($field$){$default$}");
+}
+
+void EnumFieldGenerator::GenerateCopyAggregateInitializer(
+    io::Printer* printer) const {
+  Formatter format(printer, variables_);
+  format("decltype($field$){}");
 }
 
 // ===================================================================
@@ -322,7 +336,7 @@ void RepeatedEnumFieldGenerator::GenerateClearingCode(
 void RepeatedEnumFieldGenerator::GenerateMergingCode(
     io::Printer* printer) const {
   Formatter format(printer, variables_);
-  format("$field$.MergeFrom(from.$field$);\n");
+  format("_this->$field$.MergeFrom(from.$field$);\n");
 }
 
 void RepeatedEnumFieldGenerator::GenerateSwappingCode(
@@ -336,6 +350,12 @@ void RepeatedEnumFieldGenerator::GenerateConstructorCode(
   // Not needed for repeated fields.
 }
 
+void RepeatedEnumFieldGenerator::GenerateDestructorCode(
+    io::Printer* printer) const {
+  Formatter format(printer, variables_);
+  format("$field$.~RepeatedField();\n");
+}
+
 void RepeatedEnumFieldGenerator::GenerateSerializeWithCachedSizesToArray(
     io::Printer* printer) const {
   Formatter format(printer, variables_);
@@ -392,13 +412,36 @@ void RepeatedEnumFieldGenerator::GenerateByteSize(io::Printer* printer) const {
   format("}\n");
 }
 
-void RepeatedEnumFieldGenerator::GenerateConstinitInitializer(
+void RepeatedEnumFieldGenerator::GenerateConstexprAggregateInitializer(
+    io::Printer* printer) const {
+  Formatter format(printer, variables_);
+  format("/*decltype($field$)*/{}");
+  if (descriptor_->is_packed() &&
+      HasGeneratedMethods(descriptor_->file(), options_)) {
+    format("\n, /*decltype($cached_byte_size_field$)*/{0}");
+  }
+}
+
+void RepeatedEnumFieldGenerator::GenerateAggregateInitializer(
+    io::Printer* printer) const {
+  Formatter format(printer, variables_);
+  format("decltype($field$){arena}");
+  if (descriptor_->is_packed() &&
+      HasGeneratedMethods(descriptor_->file(), options_)) {
+    // std::atomic has no copy constructor, which prevents explicit aggregate
+    // initialization pre-C++17.
+    format("\n, /*decltype($cached_byte_size_field$)*/{0}");
+  }
+}
+
+void RepeatedEnumFieldGenerator::GenerateCopyAggregateInitializer(
     io::Printer* printer) const {
   Formatter format(printer, variables_);
-  format("$name$_()");
+  format("decltype($field$){from.$field$}");
   if (descriptor_->is_packed() &&
       HasGeneratedMethods(descriptor_->file(), options_)) {
-    format("\n, $cached_byte_size_name$(0)");
+    // std::atomic has no copy constructor.
+    format("\n, /*decltype($cached_byte_size_field$)*/{0}");
   }
 }
 
diff --git a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_enum_field.h b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/enum_field.h
index 2a4ca5162bf..61bae855cd6 100644
--- a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_enum_field.h
+++ b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/enum_field.h
@@ -38,7 +38,7 @@
 #include <map>
 #include <string>
 
-#include <google/protobuf/compiler/cpp/cpp_field.h>
+#include <google/protobuf/compiler/cpp/field.h>
 
 namespace google {
 namespace protobuf {
@@ -57,12 +57,15 @@ class EnumFieldGenerator : public FieldGenerator {
   void GenerateClearingCode(io::Printer* printer) const override;
   void GenerateMergingCode(io::Printer* printer) const override;
   void GenerateSwappingCode(io::Printer* printer) const override;
-  void GenerateConstructorCode(io::Printer* printer) const override;
+  void GenerateConstructorCode(io::Printer* printer) const override {}
   void GenerateCopyConstructorCode(io::Printer* printer) const override;
   void GenerateSerializeWithCachedSizesToArray(
       io::Printer* printer) const override;
   void GenerateByteSize(io::Printer* printer) const override;
-  void GenerateConstinitInitializer(io::Printer* printer) const override;
+  void GenerateConstexprAggregateInitializer(
+      io::Printer* printer) const override;
+  void GenerateAggregateInitializer(io::Printer* printer) const override;
+  void GenerateCopyAggregateInitializer(io::Printer* printer) const override;
 
  private:
   GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(EnumFieldGenerator);
@@ -98,11 +101,17 @@ class RepeatedEnumFieldGenerator : public FieldGenerator {
   void GenerateMergingCode(io::Printer* printer) const override;
   void GenerateSwappingCode(io::Printer* printer) const override;
   void GenerateConstructorCode(io::Printer* printer) const override;
-  void GenerateCopyConstructorCode(io::Printer* printer) const override {}
+  void GenerateCopyConstructorCode(io::Printer*  /*printer*/) const override {
+    GOOGLE_CHECK(!ShouldSplit(descriptor_, options_));
+  }
+  void GenerateDestructorCode(io::Printer* printer) const override;
   void GenerateSerializeWithCachedSizesToArray(
       io::Printer* printer) const override;
   void GenerateByteSize(io::Printer* printer) const override;
-  void GenerateConstinitInitializer(io::Printer* printer) const override;
+  void GenerateConstexprAggregateInitializer(
+      io::Printer* printer) const override;
+  void GenerateAggregateInitializer(io::Printer* printer) const override;
+  void GenerateCopyAggregateInitializer(io::Printer* printer) const override;
 
  private:
   GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(RepeatedEnumFieldGenerator);
diff --git a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_extension.cc b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/extension.cc
index ef6cc81241f..ed85f75960a 100644
--- a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_extension.cc
+++ b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/extension.cc
@@ -32,13 +32,13 @@
 //  Based on original Protocol Buffers design by
 //  Sanjay Ghemawat, Jeff Dean, and others.
 
-#include <google/protobuf/compiler/cpp/cpp_extension.h>
+#include <google/protobuf/compiler/cpp/extension.h>
 
 #include <map>
 
 #include <google/protobuf/io/printer.h>
 #include <google/protobuf/stubs/strutil.h>
-#include <google/protobuf/compiler/cpp/cpp_helpers.h>
+#include <google/protobuf/compiler/cpp/helpers.h>
 #include <google/protobuf/descriptor.pb.h>
 
 namespace google {
@@ -78,7 +78,7 @@ ExtensionGenerator::ExtensionGenerator(const FieldDescriptor* descriptor,
       break;
   }
   SetCommonVars(options, &variables_);
-  SetCommonMessageDataVariables(&variables_);
+  SetCommonMessageDataVariables(descriptor_->containing_type(), &variables_);
   variables_["extendee"] =
       QualifiedClassName(descriptor_->containing_type(), options_);
   variables_["type_traits"] = type_traits_;
diff --git a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_extension.h b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/extension.h
index 5a32e845540..b94b178868a 100644
--- a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_extension.h
+++ b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/extension.h
@@ -39,7 +39,7 @@
 #include <string>
 
 #include <google/protobuf/stubs/common.h>
-#include <google/protobuf/compiler/cpp/cpp_options.h>
+#include <google/protobuf/compiler/cpp/options.h>
 
 namespace google {
 namespace protobuf {
diff --git a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_field.cc b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/field.cc
index 895f094c701..d5359b6d247 100644
--- a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_field.cc
+++ b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/field.cc
@@ -32,7 +32,7 @@
 //  Based on original Protocol Buffers design by
 //  Sanjay Ghemawat, Jeff Dean, and others.
 
-#include <google/protobuf/compiler/cpp/cpp_field.h>
+#include <google/protobuf/compiler/cpp/field.h>
 
 #include <cstdint>
 #include <memory>
@@ -40,16 +40,16 @@
 
 #include <google/protobuf/stubs/strutil.h>
 #include <google/protobuf/stubs/substitute.h>
-#include <google/protobuf/compiler/cpp/cpp_helpers.h>
-#include <google/protobuf/compiler/cpp/cpp_primitive_field.h>
-#include <google/protobuf/compiler/cpp/cpp_string_field.h>
+#include <google/protobuf/compiler/cpp/helpers.h>
+#include <google/protobuf/compiler/cpp/primitive_field.h>
+#include <google/protobuf/compiler/cpp/string_field.h>
 #include <google/protobuf/stubs/logging.h>
 #include <google/protobuf/stubs/common.h>
 #include <google/protobuf/io/printer.h>
 #include <google/protobuf/wire_format.h>
-#include <google/protobuf/compiler/cpp/cpp_enum_field.h>
-#include <google/protobuf/compiler/cpp/cpp_map_field.h>
-#include <google/protobuf/compiler/cpp/cpp_message_field.h>
+#include <google/protobuf/compiler/cpp/enum_field.h>
+#include <google/protobuf/compiler/cpp/map_field.h>
+#include <google/protobuf/compiler/cpp/message_field.h>
 #include <google/protobuf/descriptor.pb.h>
 
 namespace google {
@@ -236,7 +236,7 @@ void SetCommonFieldVariables(const FieldDescriptor* descriptor,
                              std::map<TProtoStringType, TProtoStringType>* variables,
                              const Options& options) {
   SetCommonVars(options, variables);
-  SetCommonMessageDataVariables(variables);
+  SetCommonMessageDataVariables(descriptor->containing_type(), variables);
 
   (*variables)["ns"] = Namespace(descriptor, options);
   (*variables)["name"] = FieldName(descriptor);
@@ -244,7 +244,8 @@ void SetCommonFieldVariables(const FieldDescriptor* descriptor,
   (*variables)["number"] = StrCat(descriptor->number());
   (*variables)["classname"] = ClassName(FieldScope(descriptor), false);
   (*variables)["declared_type"] = DeclaredTypeMethodName(descriptor->type());
-  (*variables)["field"] = FieldMemberName(descriptor);
+  bool split = ShouldSplit(descriptor, options);
+  (*variables)["field"] = FieldMemberName(descriptor, split);
 
   (*variables)["tag_size"] = StrCat(
       WireFormat::TagSize(descriptor->number(), descriptor->type()));
@@ -252,13 +253,8 @@ void SetCommonFieldVariables(const FieldDescriptor* descriptor,
 
   (*variables)["set_hasbit"] = "";
   (*variables)["clear_hasbit"] = "";
-  if (HasHasbit(descriptor)) {
-    (*variables)["set_hasbit_io"] =
-        StrCat("_Internal::set_has_", FieldName(descriptor), "(&",
-                     (*variables)["has_bits"], ");");
-  } else {
-    (*variables)["set_hasbit_io"] = "";
-  }
+  (*variables)["maybe_prepare_split_message"] =
+      split ? "  PrepareSplitMessageForWrite();\n" : "";
 
   AddAccessorAnnotations(descriptor, options, variables);
 
@@ -304,6 +300,36 @@ void FieldGenerator::SetInlinedStringIndex(arc_i32 inlined_string_index) {
       "u");
 }
 
+void FieldGenerator::GenerateAggregateInitializer(io::Printer* printer) const {
+  Formatter format(printer, variables_);
+  if (ShouldSplit(descriptor_, options_)) {
+    format("decltype(Impl_::Split::$name$_){arena}");
+    return;
+  }
+  format("decltype($field$){arena}");
+}
+
+void FieldGenerator::GenerateConstexprAggregateInitializer(
+    io::Printer* printer) const {
+  Formatter format(printer, variables_);
+  format("/*decltype($field$)*/{}");
+}
+
+void FieldGenerator::GenerateCopyAggregateInitializer(
+    io::Printer* printer) const {
+  Formatter format(printer, variables_);
+  format("decltype($field$){from.$field$}");
+}
+
+void FieldGenerator::GenerateCopyConstructorCode(io::Printer* printer) const {
+  if (ShouldSplit(descriptor_, options_)) {
+    // There is no copy constructor for the `Split` struct, so we need to copy
+    // the value here.
+    Formatter format(printer, variables_);
+    format("$field$ = from.$field$;\n");
+  }
+}
+
 void SetCommonOneofFieldVariables(
     const FieldDescriptor* descriptor,
     std::map<TProtoStringType, TProtoStringType>* variables) {
diff --git a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_field.h b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/field.h
index 9c3ec7fde4b..95eb96f499d 100644
--- a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_field.h
+++ b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/field.h
@@ -41,8 +41,8 @@
 #include <string>
 
 #include <google/protobuf/descriptor.h>
-#include <google/protobuf/compiler/cpp/cpp_helpers.h>
-#include <google/protobuf/compiler/cpp/cpp_options.h>
+#include <google/protobuf/compiler/cpp/helpers.h>
+#include <google/protobuf/compiler/cpp/options.h>
 
 namespace google {
 namespace protobuf {
@@ -136,7 +136,7 @@ class FieldGenerator {
   virtual void GenerateMergingCode(io::Printer* printer) const = 0;
 
   // Generates a copy constructor
-  virtual void GenerateCopyConstructorCode(io::Printer* printer) const = 0;
+  virtual void GenerateCopyConstructorCode(io::Printer* printer) const;
 
   // Generate lines of code (statements, not declarations) which swaps
   // this field and the corresponding field of another message, which
@@ -150,6 +150,9 @@ class FieldGenerator {
   // method, invoked by each of the generated constructors.
   virtual void GenerateConstructorCode(io::Printer* printer) const = 0;
 
+  // Generate initialization code for private members in the cold struct.
+  virtual void GenerateCreateSplitMessageCode(io::Printer* printer) const {}
+
   // Generate any code that needs to go in the class's SharedDtor() method,
   // invoked by the destructor.
   // Most field types don't need this, so the default implementation is empty.
@@ -165,10 +168,32 @@ class FieldGenerator {
   }
 
   // Generate initialization code for private members declared by
-  // GeneratePrivateMembers(), specifically for the constexpr constructor.
-  // These go into the constructor's initializer list and must follow that
-  // syntax (eg `field_(args)`). Does not include `:` or `,` separators.
-  virtual void GenerateConstinitInitializer(io::Printer* printer) const {}
+  // GeneratePrivateMembers(). These go into the SharedCtor's
+  // aggregate initialization of the _impl_ struct and must follow the syntax
+  // (e.g. `decltype($field$){$default$}`). Does not include `:` or `,`
+  // separators.  Default values should be specified here when possible.
+  //
+  // Note: We use `decltype($field$)` for both explicit construction and the
+  // fact that it's self-documenting.  Pre-C++17, copy elision isn't guaranteed
+  // in aggregate initialization so a valid copy/move constructor must exist
+  // (even though it's not used).  Because of this, we need to comment out the
+  // decltype and fallback to implicit construction.
+  virtual void GenerateAggregateInitializer(io::Printer* printer) const;
+
+  // Generate constinit initialization code for private members declared by
+  // GeneratePrivateMembers(). These go into the constexpr constructor's
+  // aggregate initialization of the _impl_ struct and must follow the syntax
+  // (e.g. `/*decltype($field$)*/{}`, see above). Does not
+  // include `:` or `,` separators.
+  virtual void GenerateConstexprAggregateInitializer(
+      io::Printer* printer) const;
+
+  // Generate copy initialization code for private members declared by
+  // GeneratePrivateMembers(). These go into the copy constructor's
+  // aggregate initialization of the _impl_ struct and must follow the syntax
+  // (e.g. `decltype($field$){from.$field$}`, see above). Does not
+  // include `:` or `,` separators.
+  virtual void GenerateCopyAggregateInitializer(io::Printer* printer) const;
 
   // Generate lines to serialize this field directly to the array "target",
   // which are placed within the message's SerializeWithCachedSizesToArray()
diff --git a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_file.cc b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/file.cc
index f27d876e2ac..2d79ec11e59 100644
--- a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_file.cc
+++ b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/file.cc
@@ -32,7 +32,7 @@
 //  Based on original Protocol Buffers design by
 //  Sanjay Ghemawat, Jeff Dean, and others.
 
-#include <google/protobuf/compiler/cpp/cpp_file.h>
+#include <google/protobuf/compiler/cpp/file.h>
 
 #include <iostream>
 #include <map>
@@ -46,12 +46,12 @@
 #include <google/protobuf/compiler/scc.h>
 #include <google/protobuf/io/printer.h>
 #include <google/protobuf/stubs/strutil.h>
-#include <google/protobuf/compiler/cpp/cpp_enum.h>
-#include <google/protobuf/compiler/cpp/cpp_extension.h>
-#include <google/protobuf/compiler/cpp/cpp_field.h>
-#include <google/protobuf/compiler/cpp/cpp_helpers.h>
-#include <google/protobuf/compiler/cpp/cpp_message.h>
-#include <google/protobuf/compiler/cpp/cpp_service.h>
+#include <google/protobuf/compiler/cpp/enum.h>
+#include <google/protobuf/compiler/cpp/extension.h>
+#include <google/protobuf/compiler/cpp/field.h>
+#include <google/protobuf/compiler/cpp/helpers.h>
+#include <google/protobuf/compiler/cpp/message.h>
+#include <google/protobuf/compiler/cpp/service.h>
 #include <google/protobuf/descriptor.pb.h>
 
 // Must be last.
@@ -496,10 +496,40 @@ void FileGenerator::GenerateSourceDefaultInstance(int idx,
                                                   io::Printer* printer) {
   Formatter format(printer, variables_);
   MessageGenerator* generator = message_generators_[idx].get();
+  // Generate the split instance first because it's needed in the constexpr
+  // constructor.
+  if (ShouldSplit(generator->descriptor_, options_)) {
+    // Use a union to disable the destructor of the _instance member.
+    // We can constant initialize, but the object will still have a non-trivial
+    // destructor that we need to elide.
+    format(
+        "struct $1$ {\n"
+        "  PROTOBUF_CONSTEXPR $1$()\n"
+        "      : _instance{",
+        DefaultInstanceType(generator->descriptor_, options_,
+                            /*split=*/true));
+    generator->GenerateInitDefaultSplitInstance(printer);
+    format(
+        "} {}\n"
+        "  ~$1$() {}\n"
+        "  union {\n"
+        "    $2$ _instance;\n"
+        "  };\n"
+        "};\n",
+        DefaultInstanceType(generator->descriptor_, options_, /*split=*/true),
+        StrCat(generator->classname_, "::Impl_::Split"));
+    // NO_DESTROY is not necessary for correctness. The empty destructor is
+    // enough. However, the empty destructor fails to be elided in some
+    // configurations (like non-opt or with certain sanitizers). NO_DESTROY is
+    // there just to improve performance and binary size in these builds.
+    format(
+        "PROTOBUF_ATTRIBUTE_NO_DESTROY PROTOBUF_CONSTINIT "
+        "PROTOBUF_ATTRIBUTE_INIT_PRIORITY1 $1$ $2$;\n",
+        DefaultInstanceType(generator->descriptor_, options_, /*split=*/true),
+        DefaultInstanceName(generator->descriptor_, options_, /*split=*/true));
+  }
+
   generator->GenerateConstexprConstructor(printer);
-  // Use a union to disable the destructor of the _instance member.
-  // We can constant initialize, but the object will still have a non-trivial
-  // destructor that we need to elide.
   format(
       "struct $1$ {\n"
       "  PROTOBUF_CONSTEXPR $1$()\n"
@@ -511,14 +541,11 @@ void FileGenerator::GenerateSourceDefaultInstance(int idx,
       "};\n",
       DefaultInstanceType(generator->descriptor_, options_),
       generator->classname_);
-  // NO_DESTROY is not necessary for correctness. The empty destructor is
-  // enough. However, the empty destructor fails to be elided in some
-  // configurations (like non-opt or with certain sanitizers). NO_DESTROY is
-  // there just to improve performance and binary size in these builds.
-  format("PROTOBUF_ATTRIBUTE_NO_DESTROY PROTOBUF_CONSTINIT "
-         "PROTOBUF_ATTRIBUTE_INIT_PRIORITY1 $1$ $2$;\n",
-         DefaultInstanceType(generator->descriptor_, options_),
-         DefaultInstanceName(generator->descriptor_, options_));
+  format(
+      "PROTOBUF_ATTRIBUTE_NO_DESTROY PROTOBUF_CONSTINIT "
+      "PROTOBUF_ATTRIBUTE_INIT_PRIORITY1 $1$ $2$;\n",
+      DefaultInstanceType(generator->descriptor_, options_),
+      DefaultInstanceName(generator->descriptor_, options_));
 
   for (int i = 0; i < generator->descriptor_->field_count(); i++) {
     const FieldDescriptor* field = generator->descriptor_->field(i);
@@ -526,11 +553,11 @@ void FileGenerator::GenerateSourceDefaultInstance(int idx,
       // Force the initialization of the inlined string in the default instance.
       format(
           "PROTOBUF_ATTRIBUTE_INIT_PRIORITY2 std::true_type "
-          "$1$::_init_inline_$2$_ = "
+          "$1$::Impl_::_init_inline_$2$_ = "
           "($3$._instance.$4$.Init(), std::true_type{});\n",
           ClassName(generator->descriptor_), FieldName(field),
           DefaultInstanceName(generator->descriptor_, options_),
-          FieldMemberName(field));
+          FieldMemberName(field, ShouldSplit(field, options_)));
     }
   }
 
@@ -963,6 +990,7 @@ class FileGenerator::ForwardDeclarations {
  public:
   void AddMessage(const Descriptor* d) { classes_[ClassName(d)] = d; }
   void AddEnum(const EnumDescriptor* d) { enums_[ClassName(d)] = d; }
+  void AddSplit(const Descriptor* d) { splits_[ClassName(d)] = d; }
 
   void Print(const Formatter& format, const Options& options) const {
     for (const auto& p : enums_) {
@@ -983,6 +1011,14 @@ class FileGenerator::ForwardDeclarations {
           class_desc, classname, DefaultInstanceType(class_desc, options),
           DefaultInstanceName(class_desc, options));
     }
+    for (const auto& p : splits_) {
+      const Descriptor* class_desc = p.second;
+      format(
+          "struct $1$;\n"
+          "$dllexport_decl $extern $1$ $2$;\n",
+          DefaultInstanceType(class_desc, options, /*split=*/true),
+          DefaultInstanceName(class_desc, options, /*split=*/true));
+    }
   }
 
   void PrintTopLevelDecl(const Formatter& format,
@@ -998,6 +1034,7 @@ class FileGenerator::ForwardDeclarations {
  private:
   std::map<TProtoStringType, const Descriptor*> classes_;
   std::map<TProtoStringType, const EnumDescriptor*> enums_;
+  std::map<TProtoStringType, const Descriptor*> splits_;
 };
 
 static void PublicImportDFS(const FileDescriptor* fd,
@@ -1071,6 +1108,12 @@ void FileGenerator::GenerateForwardDeclarations(io::Printer* printer) {
     if (d && !public_set.count(d->file()))
       decls[Namespace(d, options_)].AddEnum(d);
   }
+  for (const auto& mg : message_generators_) {
+    const Descriptor* d = mg->descriptor_;
+    if ((d != nullptr) && (public_set.count(d->file()) == 0u) &&
+        ShouldSplit(mg->descriptor_, options_))
+      decls[Namespace(d, options_)].AddSplit(d);
+  }
 
   {
     NamespaceOpener ns(format);
diff --git a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_file.h b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/file.h
index d8eff2feedb..805b4979bf5 100644
--- a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_file.h
+++ b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/file.h
@@ -42,10 +42,10 @@
 #include <vector>
 
 #include <google/protobuf/stubs/common.h>
-#include <google/protobuf/compiler/cpp/cpp_field.h>
-#include <google/protobuf/compiler/cpp/cpp_helpers.h>
+#include <google/protobuf/compiler/cpp/field.h>
+#include <google/protobuf/compiler/cpp/helpers.h>
 #include <google/protobuf/compiler/scc.h>
-#include <google/protobuf/compiler/cpp/cpp_options.h>
+#include <google/protobuf/compiler/cpp/options.h>
 
 namespace google {
 namespace protobuf {
diff --git a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_generator.cc b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/generator.cc
index 69443f5bf2f..0da2027a1e6 100644
--- a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_generator.cc
+++ b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/generator.cc
@@ -32,7 +32,7 @@
 //  Based on original Protocol Buffers design by
 //  Sanjay Ghemawat, Jeff Dean, and others.
 
-#include <google/protobuf/compiler/cpp/cpp_generator.h>
+#include <google/protobuf/compiler/cpp/generator.h>
 
 #include <memory>
 #include <string>
@@ -42,8 +42,8 @@
 #include <google/protobuf/stubs/strutil.h>
 #include <google/protobuf/io/printer.h>
 #include <google/protobuf/io/zero_copy_stream.h>
-#include <google/protobuf/compiler/cpp/cpp_file.h>
-#include <google/protobuf/compiler/cpp/cpp_helpers.h>
+#include <google/protobuf/compiler/cpp/file.h>
+#include <google/protobuf/compiler/cpp/helpers.h>
 #include <google/protobuf/descriptor.pb.h>
 
 namespace google {
@@ -135,12 +135,12 @@ bool CppGenerator::Generate(const FileDescriptor* file,
               .insert(options[i].second.substr(pos, next_pos - pos));
         pos = next_pos + 1;
       } while (pos < options[i].second.size());
-    } else if (options[i].first == "verified_lazy_message_sets") {
-      file_options.unverified_lazy_message_sets = false;
+    } else if (options[i].first == "verified_lazy") {
+      file_options.unverified_lazy = false;
     } else if (options[i].first == "unverified_lazy_message_sets") {
       file_options.unverified_lazy_message_sets = true;
-    } else if (options[i].first == "eagerly_verified_lazy") {
-      file_options.eagerly_verified_lazy = true;
+    } else if (options[i].first == "message_owned_arena_trial") {
+      file_options.message_owned_arena_trial = true;
     } else if (options[i].first == "force_eagerly_verified_lazy") {
       file_options.force_eagerly_verified_lazy = true;
     } else if (options[i].first == "experimental_tail_call_table_mode") {
diff --git a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_generator.h b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/generator.h
index aa63845d300..aa63845d300 100644
--- a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_generator.h
+++ b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/generator.h
diff --git a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_helpers.cc b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/helpers.cc
index f726d0fc9b5..48879f29d57 100644
--- a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_helpers.cc
+++ b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/helpers.cc
@@ -32,12 +32,13 @@
 //  Based on original Protocol Buffers design by
 //  Sanjay Ghemawat, Jeff Dean, and others.
 
-#include <google/protobuf/compiler/cpp/cpp_helpers.h>
+#include <google/protobuf/compiler/cpp/helpers.h>
 
 #include <cstdint>
 #include <functional>
 #include <limits>
 #include <map>
+#include <memory>
 #include <queue>
 #include <unordered_set>
 #include <vector>
@@ -45,8 +46,8 @@
 #include <google/protobuf/stubs/common.h>
 #include <google/protobuf/stubs/logging.h>
 #include <google/protobuf/descriptor.h>
-#include <google/protobuf/compiler/cpp/cpp_names.h>
-#include <google/protobuf/compiler/cpp/cpp_options.h>
+#include <google/protobuf/compiler/cpp/names.h>
+#include <google/protobuf/compiler/cpp/options.h>
 #include <google/protobuf/descriptor.pb.h>
 #include <google/protobuf/compiler/scc.h>
 #include <google/protobuf/io/printer.h>
@@ -182,18 +183,53 @@ void SetIntVar(const Options& options, const TProtoStringType& type,
                std::map<TProtoStringType, TProtoStringType>* variables) {
   (*variables)[type] = IntTypeName(options, type);
 }
-bool IsEagerlyVerifiedLazyImpl(const FieldDescriptor* field,
-                               const Options& options,
-                               MessageSCCAnalyzer* scc_analyzer) {
+
+// Returns true if the message can potentially allocate memory for its field.
+// This is used to determine if message-owned arena will be useful.
+bool AllocExpected(const Descriptor* descriptor) {
   return false;
 }
 
+// Describes different approaches to detect non-canonical int32 encoding. Only
+// kNever or kAlways is eligible for *simple* verification methods.
+enum class VerifyInt32Type {
+  kCustom,  // Only check if field number matches.
+  kNever,   // Do not check.
+  kAlways,  // Always check.
+};
+
+inline VerifySimpleType VerifyInt32TypeToVerifyCustom(VerifyInt32Type t) {
+  static VerifySimpleType kCustomTypes[] = {
+      VerifySimpleType::kCustom, VerifySimpleType::kCustomInt32Never,
+      VerifySimpleType::kCustomInt32Always};
+  return kCustomTypes[static_cast<arc_i32>(t) -
+                      static_cast<arc_i32>(VerifyInt32Type::kCustom)];
+}
+
 }  // namespace
 
 bool IsLazy(const FieldDescriptor* field, const Options& options,
             MessageSCCAnalyzer* scc_analyzer) {
   return IsLazilyVerifiedLazy(field, options) ||
-         IsEagerlyVerifiedLazyImpl(field, options, scc_analyzer);
+         IsEagerlyVerifiedLazy(field, options, scc_analyzer);
+}
+
+// Returns true if "field" is a message field that is backed by LazyField per
+// profile (go/pdlazy).
+inline bool IsEagerlyVerifiedLazyByProfile(const FieldDescriptor* field,
+                                           const Options& options,
+                                           MessageSCCAnalyzer* scc_analyzer) {
+  return false;
+}
+
+bool IsEagerlyVerifiedLazy(const FieldDescriptor* field, const Options& options,
+                           MessageSCCAnalyzer* scc_analyzer) {
+  return false;
+}
+
+bool IsLazilyVerifiedLazy(const FieldDescriptor* field,
+                          const Options& options) {
+  return false;
 }
 
 void SetCommonVars(const Options& options,
@@ -234,15 +270,20 @@ void SetCommonVars(const Options& options,
 }
 
 void SetCommonMessageDataVariables(
+    const Descriptor* descriptor,
     std::map<TProtoStringType, TProtoStringType>* variables) {
-  (*variables)["any_metadata"] = "_any_metadata_";
-  (*variables)["cached_size"] = "_cached_size_";
-  (*variables)["extensions"] = "_extensions_";
-  (*variables)["has_bits"] = "_has_bits_";
-  (*variables)["inlined_string_donated_array"] = "_inlined_string_donated_";
-  (*variables)["oneof_case"] = "_oneof_case_";
-  (*variables)["tracker"] = "_tracker_";
-  (*variables)["weak_field_map"] = "_weak_field_map_";
+  TProtoStringType prefix = IsMapEntryMessage(descriptor) ? "" : "_impl_.";
+  (*variables)["any_metadata"] = prefix + "_any_metadata_";
+  (*variables)["cached_size"] = prefix + "_cached_size_";
+  (*variables)["extensions"] = prefix + "_extensions_";
+  (*variables)["has_bits"] = prefix + "_has_bits_";
+  (*variables)["inlined_string_donated_array"] =
+      prefix + "_inlined_string_donated_";
+  (*variables)["oneof_case"] = prefix + "_oneof_case_";
+  (*variables)["tracker"] = "Impl_::_tracker_";
+  (*variables)["weak_field_map"] = prefix + "_weak_field_map_";
+  (*variables)["split"] = prefix + "_split_";
+  (*variables)["cached_split_ptr"] = "cached_split_ptr";
 }
 
 void SetUnknownFieldsVariable(const Descriptor* descriptor,
@@ -407,29 +448,32 @@ TProtoStringType Namespace(const EnumDescriptor* d, const Options& options) {
 }
 
 TProtoStringType DefaultInstanceType(const Descriptor* descriptor,
-                                const Options& options) {
-  return ClassName(descriptor) + "DefaultTypeInternal";
+                                const Options& /*options*/, bool split) {
+  return ClassName(descriptor) + (split ? "__Impl_Split" : "") +
+         "DefaultTypeInternal";
 }
 
 TProtoStringType DefaultInstanceName(const Descriptor* descriptor,
-                                const Options& options) {
-  return "_" + ClassName(descriptor, false) + "_default_instance_";
+                                const Options& /*options*/, bool split) {
+  return "_" + ClassName(descriptor, false) + (split ? "__Impl_Split" : "") +
+         "_default_instance_";
 }
 
 TProtoStringType DefaultInstancePtr(const Descriptor* descriptor,
-                               const Options& options) {
-  return DefaultInstanceName(descriptor, options) + "ptr_";
+                               const Options& options, bool split) {
+  return DefaultInstanceName(descriptor, options, split) + "ptr_";
 }
 
 TProtoStringType QualifiedDefaultInstanceName(const Descriptor* descriptor,
-                                         const Options& options) {
+                                         const Options& options, bool split) {
   return QualifiedFileLevelSymbol(
-      descriptor->file(), DefaultInstanceName(descriptor, options), options);
+      descriptor->file(), DefaultInstanceName(descriptor, options, split),
+      options);
 }
 
 TProtoStringType QualifiedDefaultInstancePtr(const Descriptor* descriptor,
-                                        const Options& options) {
-  return QualifiedDefaultInstanceName(descriptor, options) + "ptr_";
+                                        const Options& options, bool split) {
+  return QualifiedDefaultInstanceName(descriptor, options, split) + "ptr_";
 }
 
 TProtoStringType DescriptorTableName(const FileDescriptor* file,
@@ -469,12 +513,17 @@ TProtoStringType FieldName(const FieldDescriptor* field) {
   return result;
 }
 
-TProtoStringType FieldMemberName(const FieldDescriptor* field) {
+TProtoStringType FieldMemberName(const FieldDescriptor* field, bool split) {
+  StringPiece prefix =
+      IsMapEntryMessage(field->containing_type()) ? "" : "_impl_.";
+  StringPiece split_prefix = split ? "_split_->" : "";
   if (field->real_containing_oneof() == nullptr) {
-    return StrCat(FieldName(field), "_");
+    return StrCat(prefix, split_prefix, FieldName(field), "_");
   }
-  return StrCat(field->containing_oneof()->name(), "_.", FieldName(field),
-                      "_");
+  // Oneof fields are never split.
+  GOOGLE_CHECK(!split);
+  return StrCat(prefix, field->containing_oneof()->name(), "_.",
+                      FieldName(field), "_");
 }
 
 TProtoStringType OneofCaseConstantName(const FieldDescriptor* field) {
@@ -855,6 +904,9 @@ bool HasLazyFields(const FileDescriptor* file, const Options& options,
   return false;
 }
 
+bool ShouldSplit(const Descriptor*, const Options&) { return false; }
+bool ShouldSplit(const FieldDescriptor*, const Options&) { return false; }
+
 static bool HasRepeatedFields(const Descriptor* descriptor) {
   for (int i = 0; i < descriptor->field_count(); ++i) {
     if (descriptor->field(i)->label() == FieldDescriptor::LABEL_REPEATED) {
@@ -991,6 +1043,16 @@ bool ShouldVerify(const FileDescriptor* file, const Options& options,
   return false;
 }
 
+bool IsUtf8String(const FieldDescriptor* field) {
+  return IsProto3(field->file()) &&
+      field->type() == FieldDescriptor::TYPE_STRING;
+}
+
+VerifySimpleType ShouldVerifySimple(const Descriptor* descriptor) {
+  (void)descriptor;
+  return VerifySimpleType::kCustom;
+}
+
 bool IsStringOrMessage(const FieldDescriptor* field) {
   switch (field->cpp_type()) {
     case FieldDescriptor::CPPTYPE_INT32:
@@ -1509,12 +1571,32 @@ FileOptions_OptimizeMode GetOptimizeFor(const FileDescriptor* file,
   return FileOptions::SPEED;
 }
 
+inline bool IsMessageOwnedArenaEligible(const Descriptor* desc,
+                                        const Options& options) {
+  return GetOptimizeFor(desc->file(), options) != FileOptions::LITE_RUNTIME &&
+         !options.bootstrap && !options.opensource_runtime &&
+         AllocExpected(desc);
+}
+
 bool EnableMessageOwnedArena(const Descriptor* desc, const Options& options) {
   (void)desc;
   (void)options;
   return false;
 }
 
+bool EnableMessageOwnedArenaTrial(const Descriptor* desc,
+                                  const Options& options) {
+  return false;
+}
+
+bool HasMessageFieldOrExtension(const Descriptor* desc) {
+  if (desc->extension_range_count() > 0) return true;
+  for (const auto* f : FieldRange(desc)) {
+    if (f->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE) return true;
+  }
+  return false;
+}
+
 }  // namespace cpp
 }  // namespace compiler
 }  // namespace protobuf
diff --git a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/helpers.h b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/helpers.h
new file mode 100644
index 00000000000..690a577591e
--- /dev/null
+++ b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/helpers.h
@@ -0,0 +1,1065 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Author: [email protected] (Kenton Varda)
+//  Based on original Protocol Buffers design by
+//  Sanjay Ghemawat, Jeff Dean, and others.
+
+#ifndef GOOGLE_PROTOBUF_COMPILER_CPP_HELPERS_H__
+#define GOOGLE_PROTOBUF_COMPILER_CPP_HELPERS_H__
+
+#include <algorithm>
+#include <cstdint>
+#include <iterator>
+#include <map>
+#include <string>
+
+#include <google/protobuf/compiler/scc.h>
+#include <google/protobuf/compiler/code_generator.h>
+#include <google/protobuf/compiler/cpp/names.h>
+#include <google/protobuf/compiler/cpp/options.h>
+#include <google/protobuf/descriptor.pb.h>
+#include <google/protobuf/io/printer.h>
+#include <google/protobuf/descriptor.h>
+#include <google/protobuf/port.h>
+#include <google/protobuf/stubs/strutil.h>
+
+// Must be included last.
+#include <google/protobuf/port_def.inc>
+
+namespace google {
+namespace protobuf {
+namespace compiler {
+namespace cpp {
+
+enum class ArenaDtorNeeds { kNone = 0, kOnDemand = 1, kRequired = 2 };
+
+inline TProtoStringType ProtobufNamespace(const Options& /* options */) {
+  return "PROTOBUF_NAMESPACE_ID";
+}
+
+inline TProtoStringType MacroPrefix(const Options& /* options */) {
+  return "GOOGLE_PROTOBUF";
+}
+
+inline TProtoStringType DeprecatedAttribute(const Options& /* options */,
+                                       const FieldDescriptor* d) {
+  return d->options().deprecated() ? "PROTOBUF_DEPRECATED " : "";
+}
+
+inline TProtoStringType DeprecatedAttribute(const Options& /* options */,
+                                       const EnumValueDescriptor* d) {
+  return d->options().deprecated() ? "PROTOBUF_DEPRECATED_ENUM " : "";
+}
+
+// Commonly-used separator comments.  Thick is a line of '=', thin is a line
+// of '-'.
+extern const char kThickSeparator[];
+extern const char kThinSeparator[];
+
+void SetCommonVars(const Options& options,
+                   std::map<TProtoStringType, TProtoStringType>* variables);
+
+// Variables to access message data from the message scope.
+void SetCommonMessageDataVariables(
+    const Descriptor* descriptor,
+    std::map<TProtoStringType, TProtoStringType>* variables);
+
+void SetUnknownFieldsVariable(const Descriptor* descriptor,
+                              const Options& options,
+                              std::map<TProtoStringType, TProtoStringType>* variables);
+
+bool GetBootstrapBasename(const Options& options, const TProtoStringType& basename,
+                          TProtoStringType* bootstrap_basename);
+bool MaybeBootstrap(const Options& options, GeneratorContext* generator_context,
+                    bool bootstrap_flag, TProtoStringType* basename);
+bool IsBootstrapProto(const Options& options, const FileDescriptor* file);
+
+// Name space of the proto file. This namespace is such that the string
+// "<namespace>::some_name" is the correct fully qualified namespace.
+// This means if the package is empty the namespace is "", and otherwise
+// the namespace is "::foo::bar::...::baz" without trailing semi-colons.
+TProtoStringType Namespace(const FileDescriptor* d, const Options& options);
+TProtoStringType Namespace(const Descriptor* d, const Options& options);
+TProtoStringType Namespace(const FieldDescriptor* d, const Options& options);
+TProtoStringType Namespace(const EnumDescriptor* d, const Options& options);
+
+// Returns true if it's safe to reset "field" to zero.
+bool CanInitializeByZeroing(const FieldDescriptor* field);
+
+TProtoStringType ClassName(const Descriptor* descriptor);
+TProtoStringType ClassName(const EnumDescriptor* enum_descriptor);
+
+TProtoStringType QualifiedClassName(const Descriptor* d, const Options& options);
+TProtoStringType QualifiedClassName(const EnumDescriptor* d, const Options& options);
+
+TProtoStringType QualifiedClassName(const Descriptor* d);
+TProtoStringType QualifiedClassName(const EnumDescriptor* d);
+
+// DEPRECATED just use ClassName or QualifiedClassName, a boolean is very
+// unreadable at the callsite.
+// Returns the non-nested type name for the given type.  If "qualified" is
+// true, prefix the type with the full namespace.  For example, if you had:
+//   package foo.bar;
+//   message Baz { message Moo {} }
+// Then the qualified ClassName for Moo would be:
+//   ::foo::bar::Baz_Moo
+// While the non-qualified version would be:
+//   Baz_Moo
+inline TProtoStringType ClassName(const Descriptor* descriptor, bool qualified) {
+  return qualified ? QualifiedClassName(descriptor, Options())
+                   : ClassName(descriptor);
+}
+
+inline TProtoStringType ClassName(const EnumDescriptor* descriptor, bool qualified) {
+  return qualified ? QualifiedClassName(descriptor, Options())
+                   : ClassName(descriptor);
+}
+
+// Returns the extension name prefixed with the class name if nested but without
+// the package name.
+TProtoStringType ExtensionName(const FieldDescriptor* d);
+
+TProtoStringType QualifiedExtensionName(const FieldDescriptor* d,
+                                   const Options& options);
+TProtoStringType QualifiedExtensionName(const FieldDescriptor* d);
+
+// Type name of default instance.
+TProtoStringType DefaultInstanceType(const Descriptor* descriptor,
+                                const Options& options, bool split = false);
+
+// Non-qualified name of the default_instance of this message.
+TProtoStringType DefaultInstanceName(const Descriptor* descriptor,
+                                const Options& options, bool split = false);
+
+// Non-qualified name of the default instance pointer. This is used only for
+// implicit weak fields, where we need an extra indirection.
+TProtoStringType DefaultInstancePtr(const Descriptor* descriptor,
+                               const Options& options, bool split = false);
+
+// Fully qualified name of the default_instance of this message.
+TProtoStringType QualifiedDefaultInstanceName(const Descriptor* descriptor,
+                                         const Options& options,
+                                         bool split = false);
+
+// Fully qualified name of the default instance pointer.
+TProtoStringType QualifiedDefaultInstancePtr(const Descriptor* descriptor,
+                                        const Options& options,
+                                        bool split = false);
+
+// DescriptorTable variable name.
+TProtoStringType DescriptorTableName(const FileDescriptor* file,
+                                const Options& options);
+
+// When declaring symbol externs from another file, this macro will supply the
+// dllexport needed for the target file, if any.
+TProtoStringType FileDllExport(const FileDescriptor* file, const Options& options);
+
+// Name of the base class: google::protobuf::Message or google::protobuf::MessageLite.
+TProtoStringType SuperClassName(const Descriptor* descriptor,
+                           const Options& options);
+
+// Adds an underscore if necessary to prevent conflicting with a keyword.
+TProtoStringType ResolveKeyword(const TProtoStringType& name);
+
+// Get the (unqualified) name that should be used for this field in C++ code.
+// The name is coerced to lower-case to emulate proto1 behavior.  People
+// should be using lowercase-with-underscores style for proto field names
+// anyway, so normally this just returns field->name().
+TProtoStringType FieldName(const FieldDescriptor* field);
+
+// Returns the (unqualified) private member name for this field in C++ code.
+TProtoStringType FieldMemberName(const FieldDescriptor* field, bool split);
+
+// Returns an estimate of the compiler's alignment for the field.  This
+// can't guarantee to be correct because the generated code could be compiled on
+// different systems with different alignment rules.  The estimates below assume
+// 64-bit pointers.
+int EstimateAlignmentSize(const FieldDescriptor* field);
+
+// Get the unqualified name that should be used for a field's field
+// number constant.
+TProtoStringType FieldConstantName(const FieldDescriptor* field);
+
+// Returns the scope where the field was defined (for extensions, this is
+// different from the message type to which the field applies).
+inline const Descriptor* FieldScope(const FieldDescriptor* field) {
+  return field->is_extension() ? field->extension_scope()
+                               : field->containing_type();
+}
+
+// Returns the fully-qualified type name field->message_type().  Usually this
+// is just ClassName(field->message_type(), true);
+TProtoStringType FieldMessageTypeName(const FieldDescriptor* field,
+                                 const Options& options);
+
+// Get the C++ type name for a primitive type (e.g. "double", "::google::protobuf::int32", etc.).
+const char* PrimitiveTypeName(FieldDescriptor::CppType type);
+TProtoStringType PrimitiveTypeName(const Options& options,
+                              FieldDescriptor::CppType type);
+
+// Get the declared type name in CamelCase format, as is used e.g. for the
+// methods of WireFormat.  For example, TYPE_INT32 becomes "Int32".
+const char* DeclaredTypeMethodName(FieldDescriptor::Type type);
+
+// Return the code that evaluates to the number when compiled.
+TProtoStringType Int32ToString(int number);
+
+// Get code that evaluates to the field's default value.
+TProtoStringType DefaultValue(const Options& options, const FieldDescriptor* field);
+
+// Compatibility function for callers outside proto2.
+TProtoStringType DefaultValue(const FieldDescriptor* field);
+
+// Convert a file name into a valid identifier.
+TProtoStringType FilenameIdentifier(const TProtoStringType& filename);
+
+// For each .proto file generates a unique name. To prevent collisions of
+// symbols in the global namespace
+TProtoStringType UniqueName(const TProtoStringType& name, const TProtoStringType& filename,
+                       const Options& options);
+inline TProtoStringType UniqueName(const TProtoStringType& name, const FileDescriptor* d,
+                              const Options& options) {
+  return UniqueName(name, d->name(), options);
+}
+inline TProtoStringType UniqueName(const TProtoStringType& name, const Descriptor* d,
+                              const Options& options) {
+  return UniqueName(name, d->file(), options);
+}
+inline TProtoStringType UniqueName(const TProtoStringType& name, const EnumDescriptor* d,
+                              const Options& options) {
+  return UniqueName(name, d->file(), options);
+}
+inline TProtoStringType UniqueName(const TProtoStringType& name,
+                              const ServiceDescriptor* d,
+                              const Options& options) {
+  return UniqueName(name, d->file(), options);
+}
+
+// Versions for call sites that only support the internal runtime (like proto1
+// support).
+inline Options InternalRuntimeOptions() {
+  Options options;
+  options.opensource_runtime = false;
+  return options;
+}
+inline TProtoStringType UniqueName(const TProtoStringType& name,
+                              const TProtoStringType& filename) {
+  return UniqueName(name, filename, InternalRuntimeOptions());
+}
+inline TProtoStringType UniqueName(const TProtoStringType& name,
+                              const FileDescriptor* d) {
+  return UniqueName(name, d->name(), InternalRuntimeOptions());
+}
+inline TProtoStringType UniqueName(const TProtoStringType& name, const Descriptor* d) {
+  return UniqueName(name, d->file(), InternalRuntimeOptions());
+}
+inline TProtoStringType UniqueName(const TProtoStringType& name,
+                              const EnumDescriptor* d) {
+  return UniqueName(name, d->file(), InternalRuntimeOptions());
+}
+inline TProtoStringType UniqueName(const TProtoStringType& name,
+                              const ServiceDescriptor* d) {
+  return UniqueName(name, d->file(), InternalRuntimeOptions());
+}
+
+// Return the qualified C++ name for a file level symbol.
+TProtoStringType QualifiedFileLevelSymbol(const FileDescriptor* file,
+                                     const TProtoStringType& name,
+                                     const Options& options);
+
+// Escape C++ trigraphs by escaping question marks to \?
+TProtoStringType EscapeTrigraphs(const TProtoStringType& to_escape);
+
+// Escaped function name to eliminate naming conflict.
+TProtoStringType SafeFunctionName(const Descriptor* descriptor,
+                             const FieldDescriptor* field,
+                             const TProtoStringType& prefix);
+
+// Returns true if generated messages have public unknown fields accessors
+inline bool PublicUnknownFieldsAccessors(const Descriptor* message) {
+  return message->file()->syntax() != FileDescriptor::SYNTAX_PROTO3;
+}
+
+// Returns the optimize mode for <file>, respecting <options.enforce_lite>.
+FileOptions_OptimizeMode GetOptimizeFor(const FileDescriptor* file,
+                                        const Options& options);
+
+// Determines whether unknown fields will be stored in an UnknownFieldSet or
+// a string.
+inline bool UseUnknownFieldSet(const FileDescriptor* file,
+                               const Options& options) {
+  return GetOptimizeFor(file, options) != FileOptions::LITE_RUNTIME;
+}
+
+inline bool IsWeak(const FieldDescriptor* field, const Options& options) {
+  if (field->options().weak()) {
+    GOOGLE_CHECK(!options.opensource_runtime);
+    return true;
+  }
+  return false;
+}
+
+bool IsStringInlined(const FieldDescriptor* descriptor, const Options& options);
+
+// For a string field, returns the effective ctype.  If the actual ctype is
+// not supported, returns the default of STRING.
+FieldOptions::CType EffectiveStringCType(const FieldDescriptor* field,
+                                         const Options& options);
+
+inline bool IsCord(const FieldDescriptor* field, const Options& options) {
+  return field->cpp_type() == FieldDescriptor::CPPTYPE_STRING &&
+         EffectiveStringCType(field, options) == FieldOptions::CORD;
+}
+
+inline bool IsString(const FieldDescriptor* field, const Options& options) {
+  return field->cpp_type() == FieldDescriptor::CPPTYPE_STRING &&
+         EffectiveStringCType(field, options) == FieldOptions::STRING;
+}
+
+inline bool IsStringPiece(const FieldDescriptor* field,
+                          const Options& options) {
+  return field->cpp_type() == FieldDescriptor::CPPTYPE_STRING &&
+         EffectiveStringCType(field, options) == FieldOptions::STRING_PIECE;
+}
+
+class MessageSCCAnalyzer;
+
+// Does the given FileDescriptor use lazy fields?
+bool HasLazyFields(const FileDescriptor* file, const Options& options,
+                   MessageSCCAnalyzer* scc_analyzer);
+
+// Is the given field a supported lazy field?
+bool IsLazy(const FieldDescriptor* field, const Options& options,
+            MessageSCCAnalyzer* scc_analyzer);
+
+// Is this an explicit (non-profile driven) lazy field, as denoted by
+// lazy/unverified_lazy in the descriptor?
+inline bool IsExplicitLazy(const FieldDescriptor* field) {
+  return field->options().lazy() || field->options().unverified_lazy();
+}
+
+bool IsEagerlyVerifiedLazy(const FieldDescriptor* field, const Options& options,
+                           MessageSCCAnalyzer* scc_analyzer);
+
+bool IsLazilyVerifiedLazy(const FieldDescriptor* field, const Options& options);
+
+// Is the given message being split (go/pdsplit)?
+bool ShouldSplit(const Descriptor* desc, const Options& options);
+
+// Is the given field being split out?
+bool ShouldSplit(const FieldDescriptor* field, const Options& options);
+
+inline bool IsFieldUsed(const FieldDescriptor* /* field */,
+                        const Options& /* options */) {
+  return true;
+}
+
+// Returns true if "field" is stripped.
+inline bool IsFieldStripped(const FieldDescriptor* /*field*/,
+                            const Options& /*options*/) {
+  return false;
+}
+
+// Does the file contain any definitions that need extension_set.h?
+bool HasExtensionsOrExtendableMessage(const FileDescriptor* file);
+
+// Does the file have any repeated fields, necessitating the file to include
+// repeated_field.h? This does not include repeated extensions, since those are
+// all stored internally in an ExtensionSet, not a separate RepeatedField*.
+bool HasRepeatedFields(const FileDescriptor* file);
+
+// Does the file have any string/bytes fields with ctype=STRING_PIECE? This
+// does not include extensions, since ctype is ignored for extensions.
+bool HasStringPieceFields(const FileDescriptor* file, const Options& options);
+
+// Does the file have any string/bytes fields with ctype=CORD? This does not
+// include extensions, since ctype is ignored for extensions.
+bool HasCordFields(const FileDescriptor* file, const Options& options);
+
+// Does the file have any map fields, necessitating the file to include
+// map_field_inl.h and map.h.
+bool HasMapFields(const FileDescriptor* file);
+
+// Does this file have any enum type definitions?
+bool HasEnumDefinitions(const FileDescriptor* file);
+
+// Does this file have generated parsing, serialization, and other
+// standard methods for which reflection-based fallback implementations exist?
+inline bool HasGeneratedMethods(const FileDescriptor* file,
+                                const Options& options) {
+  return GetOptimizeFor(file, options) != FileOptions::CODE_SIZE;
+}
+
+// Do message classes in this file have descriptor and reflection methods?
+inline bool HasDescriptorMethods(const FileDescriptor* file,
+                                 const Options& options) {
+  return GetOptimizeFor(file, options) != FileOptions::LITE_RUNTIME;
+}
+
+// Should we generate generic services for this file?
+inline bool HasGenericServices(const FileDescriptor* file,
+                               const Options& options) {
+  return file->service_count() > 0 &&
+         GetOptimizeFor(file, options) != FileOptions::LITE_RUNTIME &&
+         file->options().cc_generic_services();
+}
+
+inline bool IsProto2MessageSet(const Descriptor* descriptor,
+                               const Options& options) {
+  return !options.opensource_runtime &&
+         options.enforce_mode != EnforceOptimizeMode::kLiteRuntime &&
+         !options.lite_implicit_weak_fields &&
+         descriptor->options().message_set_wire_format() &&
+         descriptor->full_name() == "google.protobuf.bridge.MessageSet";
+}
+
+inline bool IsMapEntryMessage(const Descriptor* descriptor) {
+  return descriptor->options().map_entry();
+}
+
+// Returns true if the field's CPPTYPE is string or message.
+bool IsStringOrMessage(const FieldDescriptor* field);
+
+TProtoStringType UnderscoresToCamelCase(const TProtoStringType& input,
+                                   bool cap_next_letter);
+
+inline bool IsProto3(const FileDescriptor* file) {
+  return file->syntax() == FileDescriptor::SYNTAX_PROTO3;
+}
+
+inline bool HasHasbit(const FieldDescriptor* field) {
+  // This predicate includes proto3 message fields only if they have "optional".
+  //   Foo submsg1 = 1;           // HasHasbit() == false
+  //   optional Foo submsg2 = 2;  // HasHasbit() == true
+  // This is slightly odd, as adding "optional" to a singular proto3 field does
+  // not change the semantics or API. However whenever any field in a message
+  // has a hasbit, it forces reflection to include hasbit offsets for *all*
+  // fields, even if almost all of them are set to -1 (no hasbit). So to avoid
+  // causing a sudden size regression for ~all proto3 messages, we give proto3
+  // message fields a hasbit only if "optional" is present. If the user is
+  // explicitly writing "optional", it is likely they are writing it on
+  // primitive fields also.
+  return (field->has_optional_keyword() || field->is_required()) &&
+         !field->options().weak();
+}
+
+// Returns true if 'enum' semantics are such that unknown values are preserved
+// in the enum field itself, rather than going to the UnknownFieldSet.
+inline bool HasPreservingUnknownEnumSemantics(const FieldDescriptor* field) {
+  return field->file()->syntax() == FileDescriptor::SYNTAX_PROTO3;
+}
+
+inline bool IsCrossFileMessage(const FieldDescriptor* field) {
+  return field->type() == FieldDescriptor::TYPE_MESSAGE &&
+         field->message_type()->file() != field->file();
+}
+
+inline TProtoStringType MakeDefaultName(const FieldDescriptor* field) {
+  return StrCat("_i_give_permission_to_break_this_code_default_",
+                      FieldName(field), "_");
+}
+
+// Semantically distinct from MakeDefaultName in that it gives the C++ code
+// referencing a default field from the message scope, rather than just the
+// variable name.
+// For example, declarations of default variables should always use just
+// MakeDefaultName to produce code like:
+//   Type _i_give_permission_to_break_this_code_default_field_;
+//
+// Code that references these should use MakeDefaultFieldName, in case the field
+// exists at some nested level like:
+//   internal_container_._i_give_permission_to_break_this_code_default_field_;
+inline TProtoStringType MakeDefaultFieldName(const FieldDescriptor* field) {
+  return StrCat("Impl_::", MakeDefaultName(field));
+}
+
+inline TProtoStringType MakeVarintCachedSizeName(const FieldDescriptor* field) {
+  return StrCat("_", FieldName(field), "_cached_byte_size_");
+}
+
+// Semantically distinct from MakeVarintCachedSizeName in that it gives the C++
+// code referencing the object from the message scope, rather than just the
+// variable name.
+// For example, declarations of default variables should always use just
+// MakeVarintCachedSizeName to produce code like:
+//   Type _field_cached_byte_size_;
+//
+// Code that references these variables should use
+// MakeVarintCachedSizeFieldName, in case the field exists at some nested level
+// like:
+//   internal_container_._field_cached_byte_size_;
+inline TProtoStringType MakeVarintCachedSizeFieldName(const FieldDescriptor* field,
+                                                 bool split) {
+  return StrCat("_impl_.", split ? "_split_->" : "", "_",
+                      FieldName(field), "_cached_byte_size_");
+}
+
+// Note: A lot of libraries detect Any protos based on Descriptor::full_name()
+// while the two functions below use FileDescriptor::name(). In a sane world the
+// two approaches should be equivalent. But if you are dealing with descriptors
+// from untrusted sources, you might need to match semantics across libraries.
+bool IsAnyMessage(const FileDescriptor* descriptor, const Options& options);
+bool IsAnyMessage(const Descriptor* descriptor, const Options& options);
+
+bool IsWellKnownMessage(const FileDescriptor* descriptor);
+
+inline TProtoStringType IncludeGuard(const FileDescriptor* file, bool pb_h,
+                                bool deps,
+                                const Options& options) {
+  // If we are generating a .pb.h file and the proto_h option is enabled, then
+  // the .pb.h gets an extra suffix.
+  TProtoStringType filename_identifier = FilenameIdentifier(
+      file->name() + (deps ? ".deps": "") + (pb_h && options.proto_h ? ".pb.h" : ""));
+
+  if (IsWellKnownMessage(file)) {
+    // For well-known messages we need third_party/protobuf and net/proto2 to
+    // have distinct include guards, because some source files include both and
+    // both need to be defined (the third_party copies will be in the
+    // google::protobuf_opensource namespace).
+    return MacroPrefix(options) + "_INCLUDED_" + filename_identifier;
+  } else {
+    // Ideally this case would use distinct include guards for opensource and
+    // google3 protos also.  (The behavior of "first #included wins" is not
+    // ideal).  But unfortunately some legacy code includes both and depends on
+    // the identical include guards to avoid compile errors.
+    //
+    // We should clean this up so that this case can be removed.
+    return "GOOGLE_PROTOBUF_INCLUDED_" + filename_identifier;
+  }
+}
+
+// Returns the OptimizeMode for this file, furthermore it updates a status
+// bool if has_opt_codesize_extension is non-null. If this status bool is true
+// it means this file contains an extension that itself is defined as
+// optimized_for = CODE_SIZE.
+FileOptions_OptimizeMode GetOptimizeFor(const FileDescriptor* file,
+                                        const Options& options,
+                                        bool* has_opt_codesize_extension);
+inline FileOptions_OptimizeMode GetOptimizeFor(const FileDescriptor* file,
+                                               const Options& options) {
+  return GetOptimizeFor(file, options, nullptr);
+}
+inline bool NeedsEagerDescriptorAssignment(const FileDescriptor* file,
+                                           const Options& options) {
+  bool has_opt_codesize_extension;
+  if (GetOptimizeFor(file, options, &has_opt_codesize_extension) ==
+          FileOptions::CODE_SIZE &&
+      has_opt_codesize_extension) {
+    // If this filedescriptor contains an extension from another file which
+    // is optimized_for = CODE_SIZE. We need to be careful in the ordering so
+    // we eagerly build the descriptors in the dependencies before building
+    // the descriptors of this file.
+    return true;
+  } else {
+    // If we have a generated code based parser we never need eager
+    // initialization of descriptors of our deps.
+    return false;
+  }
+}
+
+// This orders the messages in a .pb.cc as it's outputted by file.cc
+void FlattenMessagesInFile(const FileDescriptor* file,
+                           std::vector<const Descriptor*>* result);
+inline std::vector<const Descriptor*> FlattenMessagesInFile(
+    const FileDescriptor* file) {
+  std::vector<const Descriptor*> result;
+  FlattenMessagesInFile(file, &result);
+  return result;
+}
+
+template <typename F>
+void ForEachMessage(const Descriptor* descriptor, F&& func) {
+  for (int i = 0; i < descriptor->nested_type_count(); i++)
+    ForEachMessage(descriptor->nested_type(i), std::forward<F&&>(func));
+  func(descriptor);
+}
+
+template <typename F>
+void ForEachMessage(const FileDescriptor* descriptor, F&& func) {
+  for (int i = 0; i < descriptor->message_type_count(); i++)
+    ForEachMessage(descriptor->message_type(i), std::forward<F&&>(func));
+}
+
+bool HasWeakFields(const Descriptor* desc, const Options& options);
+bool HasWeakFields(const FileDescriptor* desc, const Options& options);
+
+// Returns true if the "required" restriction check should be ignored for the
+// given field.
+inline static bool ShouldIgnoreRequiredFieldCheck(const FieldDescriptor* field,
+                                                  const Options& options) {
+  // Do not check "required" for lazily verified lazy fields.
+  return IsLazilyVerifiedLazy(field, options);
+}
+
+struct MessageAnalysis {
+  bool is_recursive = false;
+  bool contains_cord = false;
+  bool contains_extension = false;
+  bool contains_required = false;
+  bool contains_weak = false;  // Implicit weak as well.
+};
+
+// This class is used in FileGenerator, to ensure linear instead of
+// quadratic performance, if we do this per message we would get O(V*(V+E)).
+// Logically this is just only used in message.cc, but in the header for
+// FileGenerator to help share it.
+class PROTOC_EXPORT MessageSCCAnalyzer {
+ public:
+  explicit MessageSCCAnalyzer(const Options& options) : options_(options) {}
+
+  MessageAnalysis GetSCCAnalysis(const SCC* scc);
+
+  bool HasRequiredFields(const Descriptor* descriptor) {
+    MessageAnalysis result = GetSCCAnalysis(GetSCC(descriptor));
+    return result.contains_required || result.contains_extension;
+  }
+  bool HasWeakField(const Descriptor* descriptor) {
+    MessageAnalysis result = GetSCCAnalysis(GetSCC(descriptor));
+    return result.contains_weak;
+  }
+  const SCC* GetSCC(const Descriptor* descriptor) {
+    return analyzer_.GetSCC(descriptor);
+  }
+
+ private:
+  struct DepsGenerator {
+    std::vector<const Descriptor*> operator()(const Descriptor* desc) const {
+      std::vector<const Descriptor*> deps;
+      for (int i = 0; i < desc->field_count(); i++) {
+        if (desc->field(i)->message_type()) {
+          deps.push_back(desc->field(i)->message_type());
+        }
+      }
+      return deps;
+    }
+  };
+  SCCAnalyzer<DepsGenerator> analyzer_;
+  Options options_;
+  std::map<const SCC*, MessageAnalysis> analysis_cache_;
+};
+
+void ListAllFields(const Descriptor* d,
+                   std::vector<const FieldDescriptor*>* fields);
+void ListAllFields(const FileDescriptor* d,
+                   std::vector<const FieldDescriptor*>* fields);
+
+template <class T>
+void ForEachField(const Descriptor* d, T&& func) {
+  for (int i = 0; i < d->nested_type_count(); i++) {
+    ForEachField(d->nested_type(i), std::forward<T&&>(func));
+  }
+  for (int i = 0; i < d->extension_count(); i++) {
+    func(d->extension(i));
+  }
+  for (int i = 0; i < d->field_count(); i++) {
+    func(d->field(i));
+  }
+}
+
+template <class T>
+void ForEachField(const FileDescriptor* d, T&& func) {
+  for (int i = 0; i < d->message_type_count(); i++) {
+    ForEachField(d->message_type(i), std::forward<T&&>(func));
+  }
+  for (int i = 0; i < d->extension_count(); i++) {
+    func(d->extension(i));
+  }
+}
+
+void ListAllTypesForServices(const FileDescriptor* fd,
+                             std::vector<const Descriptor*>* types);
+
+// Indicates whether we should use implicit weak fields for this file.
+bool UsingImplicitWeakFields(const FileDescriptor* file,
+                             const Options& options);
+
+// Indicates whether to treat this field as implicitly weak.
+bool IsImplicitWeakField(const FieldDescriptor* field, const Options& options,
+                         MessageSCCAnalyzer* scc_analyzer);
+
+inline bool HasSimpleBaseClass(const Descriptor* desc, const Options& options) {
+  if (!HasDescriptorMethods(desc->file(), options)) return false;
+  if (desc->extension_range_count() != 0) return false;
+  if (desc->field_count() == 0) return true;
+  // TODO(jorg): Support additional common message types with only one
+  // or two fields
+  return false;
+}
+
+inline bool HasSimpleBaseClasses(const FileDescriptor* file,
+                                 const Options& options) {
+  bool v = false;
+  ForEachMessage(file, [&v, &options](const Descriptor* desc) {
+    v |= HasSimpleBaseClass(desc, options);
+  });
+  return v;
+}
+
+inline TProtoStringType SimpleBaseClass(const Descriptor* desc,
+                                   const Options& options) {
+  if (!HasDescriptorMethods(desc->file(), options)) return "";
+  if (desc->extension_range_count() != 0) return "";
+  if (desc->field_count() == 0) {
+    return "ZeroFieldsBase";
+  }
+  // TODO(jorg): Support additional common message types with only one
+  // or two fields
+  return "";
+}
+
+// Returns true if this message has a _tracker_ field.
+inline bool HasTracker(const Descriptor* desc, const Options& options) {
+  return options.field_listener_options.inject_field_listener_events &&
+         desc->file()->options().optimize_for() !=
+             google::protobuf::FileOptions::LITE_RUNTIME;
+}
+
+// Returns true if this message needs an Impl_ struct for it's data.
+inline bool HasImplData(const Descriptor* desc, const Options& options) {
+  return !HasSimpleBaseClass(desc, options);
+}
+
+// Formatter is a functor class which acts as a closure around printer and
+// the variable map. It's much like printer->Print except it supports both named
+// variables that are substituted using a key value map and direct arguments. In
+// the format string $1$, $2$, etc... are substituted for the first, second, ...
+// direct argument respectively in the format call, it accepts both strings and
+// integers. The implementation verifies all arguments are used and are "first"
+// used in order of appearance in the argument list. For example,
+//
+// Format("return array[$1$];", 3) -> "return array[3];"
+// Format("array[$2$] = $1$;", "Bla", 3) -> FATAL error (wrong order)
+// Format("array[$1$] = $2$;", 3, "Bla") -> "array[3] = Bla;"
+//
+// The arguments can be used more than once like
+//
+// Format("array[$1$] = $2$;  // Index = $1$", 3, "Bla") ->
+//        "array[3] = Bla;  // Index = 3"
+//
+// If you use more arguments use the following style to help the reader,
+//
+// Format("int $1$() {\n"
+//        "  array[$2$] = $3$;\n"
+//        "  return $4$;"
+//        "}\n",
+//        funname, // 1
+//        idx,  // 2
+//        varname,  // 3
+//        retval);  // 4
+//
+// but consider using named variables. Named variables like $foo$, with some
+// identifier foo, are looked up in the map. One additional feature is that
+// spaces are accepted between the '$' delimiters, $ foo$ will
+// substitute to " bar" if foo stands for "bar", but in case it's empty
+// will substitute to "". Hence, for example,
+//
+// Format(vars, "$dllexport $void fun();") -> "void fun();"
+//                                            "__declspec(export) void fun();"
+//
+// which is convenient to prevent double, leading or trailing spaces.
+class PROTOC_EXPORT Formatter {
+ public:
+  explicit Formatter(io::Printer* printer) : printer_(printer) {}
+  Formatter(io::Printer* printer,
+            const std::map<TProtoStringType, TProtoStringType>& vars)
+      : printer_(printer), vars_(vars) {}
+
+  template <typename T>
+  void Set(const TProtoStringType& key, const T& value) {
+    vars_[key] = ToString(value);
+  }
+
+  void AddMap(const std::map<TProtoStringType, TProtoStringType>& vars) {
+    for (const auto& keyval : vars) vars_[keyval.first] = keyval.second;
+  }
+
+  template <typename... Args>
+  void operator()(const char* format, const Args&... args) const {
+    printer_->FormatInternal({ToString(args)...}, vars_, format);
+  }
+
+  void Indent() const { printer_->Indent(); }
+  void Outdent() const { printer_->Outdent(); }
+  io::Printer* printer() const { return printer_; }
+
+  class PROTOC_EXPORT ScopedIndenter {
+   public:
+    explicit ScopedIndenter(Formatter* format) : format_(format) {
+      format_->Indent();
+    }
+    ~ScopedIndenter() { format_->Outdent(); }
+
+   private:
+    Formatter* format_;
+  };
+
+  PROTOBUF_NODISCARD ScopedIndenter ScopedIndent() {
+    return ScopedIndenter(this);
+  }
+  template <typename... Args>
+  PROTOBUF_NODISCARD ScopedIndenter ScopedIndent(const char* format,
+                                                 const Args&&... args) {
+    (*this)(format, static_cast<Args&&>(args)...);
+    return ScopedIndenter(this);
+  }
+
+  class PROTOC_EXPORT SaveState {
+   public:
+    explicit SaveState(Formatter* format)
+        : format_(format), vars_(format->vars_) {}
+    ~SaveState() { format_->vars_.swap(vars_); }
+
+   private:
+    Formatter* format_;
+    std::map<TProtoStringType, TProtoStringType> vars_;
+  };
+
+ private:
+  io::Printer* printer_;
+  std::map<TProtoStringType, TProtoStringType> vars_;
+
+  // Convenience overloads to accept different types as arguments.
+  static TProtoStringType ToString(const TProtoStringType& s) { return s; }
+  template <typename I, typename = typename std::enable_if<
+                            std::is_integral<I>::value>::type>
+  static TProtoStringType ToString(I x) {
+    return StrCat(x);
+  }
+  static TProtoStringType ToString(strings::Hex x) { return StrCat(x); }
+  static TProtoStringType ToString(const FieldDescriptor* d) { return Payload(d); }
+  static TProtoStringType ToString(const Descriptor* d) { return Payload(d); }
+  static TProtoStringType ToString(const EnumDescriptor* d) { return Payload(d); }
+  static TProtoStringType ToString(const EnumValueDescriptor* d) {
+    return Payload(d);
+  }
+  static TProtoStringType ToString(const OneofDescriptor* d) { return Payload(d); }
+
+  template <typename Descriptor>
+  static TProtoStringType Payload(const Descriptor* descriptor) {
+    std::vector<int> path;
+    descriptor->GetLocationPath(&path);
+    GeneratedCodeInfo::Annotation annotation;
+    for (int index : path) {
+      annotation.add_path(index);
+    }
+    annotation.set_source_file(descriptor->file()->name());
+    return annotation.SerializeAsString();
+  }
+};
+
+template <class T>
+void PrintFieldComment(const Formatter& format, const T* field) {
+  // Print the field's (or oneof's) proto-syntax definition as a comment.
+  // We don't want to print group bodies so we cut off after the first
+  // line.
+  DebugStringOptions options;
+  options.elide_group_body = true;
+  options.elide_oneof_body = true;
+  TProtoStringType def = field->DebugStringWithOptions(options);
+  format("// $1$\n", def.substr(0, def.find_first_of('\n')));
+}
+
+class PROTOC_EXPORT NamespaceOpener {
+ public:
+  explicit NamespaceOpener(const Formatter& format)
+      : printer_(format.printer()) {}
+  NamespaceOpener(const TProtoStringType& name, const Formatter& format)
+      : NamespaceOpener(format) {
+    ChangeTo(name);
+  }
+  ~NamespaceOpener() { ChangeTo(""); }
+
+  void ChangeTo(const TProtoStringType& name) {
+    std::vector<TProtoStringType> new_stack_ =
+        Split(name, "::", true);
+    size_t len = std::min(name_stack_.size(), new_stack_.size());
+    size_t common_idx = 0;
+    while (common_idx < len) {
+      if (name_stack_[common_idx] != new_stack_[common_idx]) break;
+      common_idx++;
+    }
+    for (auto it = name_stack_.crbegin();
+         it != name_stack_.crend() - common_idx; ++it) {
+      if (*it == "PROTOBUF_NAMESPACE_ID") {
+        printer_->Print("PROTOBUF_NAMESPACE_CLOSE\n");
+      } else {
+        printer_->Print("}  // namespace $ns$\n", "ns", *it);
+      }
+    }
+    name_stack_.swap(new_stack_);
+    for (size_t i = common_idx; i < name_stack_.size(); ++i) {
+      if (name_stack_[i] == "PROTOBUF_NAMESPACE_ID") {
+        printer_->Print("PROTOBUF_NAMESPACE_OPEN\n");
+      } else {
+        printer_->Print("namespace $ns$ {\n", "ns", name_stack_[i]);
+      }
+    }
+  }
+
+ private:
+  io::Printer* printer_;
+  std::vector<TProtoStringType> name_stack_;
+};
+
+enum class Utf8CheckMode {
+  kStrict = 0,  // Parsing will fail if non UTF-8 data is in string fields.
+  kVerify = 1,  // Only log an error but parsing will succeed.
+  kNone = 2,    // No UTF-8 check.
+};
+
+Utf8CheckMode GetUtf8CheckMode(const FieldDescriptor* field,
+                               const Options& options);
+
+void GenerateUtf8CheckCodeForString(const FieldDescriptor* field,
+                                    const Options& options, bool for_parse,
+                                    const char* parameters,
+                                    const Formatter& format);
+
+void GenerateUtf8CheckCodeForCord(const FieldDescriptor* field,
+                                  const Options& options, bool for_parse,
+                                  const char* parameters,
+                                  const Formatter& format);
+
+template <typename T>
+struct FieldRangeImpl {
+  struct Iterator {
+    using iterator_category = std::forward_iterator_tag;
+    using value_type = const FieldDescriptor*;
+    using difference_type = int;
+
+    value_type operator*() { return descriptor->field(idx); }
+
+    friend bool operator==(const Iterator& a, const Iterator& b) {
+      GOOGLE_DCHECK(a.descriptor == b.descriptor);
+      return a.idx == b.idx;
+    }
+    friend bool operator!=(const Iterator& a, const Iterator& b) {
+      return !(a == b);
+    }
+
+    Iterator& operator++() {
+      idx++;
+      return *this;
+    }
+
+    int idx;
+    const T* descriptor;
+  };
+
+  Iterator begin() const { return {0, descriptor}; }
+  Iterator end() const { return {descriptor->field_count(), descriptor}; }
+
+  const T* descriptor;
+};
+
+template <typename T>
+FieldRangeImpl<T> FieldRange(const T* desc) {
+  return {desc};
+}
+
+struct OneOfRangeImpl {
+  struct Iterator {
+    using iterator_category = std::forward_iterator_tag;
+    using value_type = const OneofDescriptor*;
+    using difference_type = int;
+
+    value_type operator*() { return descriptor->oneof_decl(idx); }
+
+    friend bool operator==(const Iterator& a, const Iterator& b) {
+      GOOGLE_DCHECK(a.descriptor == b.descriptor);
+      return a.idx == b.idx;
+    }
+    friend bool operator!=(const Iterator& a, const Iterator& b) {
+      return !(a == b);
+    }
+
+    Iterator& operator++() {
+      idx++;
+      return *this;
+    }
+
+    int idx;
+    const Descriptor* descriptor;
+  };
+
+  Iterator begin() const { return {0, descriptor}; }
+  Iterator end() const {
+    return {descriptor->real_oneof_decl_count(), descriptor};
+  }
+
+  const Descriptor* descriptor;
+};
+
+inline OneOfRangeImpl OneOfRange(const Descriptor* desc) { return {desc}; }
+
+PROTOC_EXPORT TProtoStringType StripProto(const TProtoStringType& filename);
+
+bool EnableMessageOwnedArena(const Descriptor* desc, const Options& options);
+
+bool EnableMessageOwnedArenaTrial(const Descriptor* desc,
+                                  const Options& options);
+
+bool ShouldVerify(const Descriptor* descriptor, const Options& options,
+                  MessageSCCAnalyzer* scc_analyzer);
+bool ShouldVerify(const FileDescriptor* file, const Options& options,
+                  MessageSCCAnalyzer* scc_analyzer);
+
+// Indicates whether to use predefined verify methods for a given message. If a
+// message is "simple" and needs no special verification per field (e.g. message
+// field, repeated packed, UTF8 string, etc.), we can use either VerifySimple or
+// VerifySimpleAlwaysCheckInt32 methods as all verification can be done based on
+// the wire type.
+//
+// Otherwise, we need "custom" verify methods tailored to a message to pass
+// which field needs a special verification; i.e. InternalVerify.
+enum class VerifySimpleType {
+  kSimpleInt32Never,   // Use VerifySimple
+  kSimpleInt32Always,  // Use VerifySimpleAlwaysCheckInt32
+  kCustom,             // Use InternalVerify and check only for int32
+  kCustomInt32Never,   // Use InternalVerify but never check for int32
+  kCustomInt32Always,  // Use InternalVerify and always check for int32
+};
+
+// Returns VerifySimpleType if messages can be verified by predefined methods.
+VerifySimpleType ShouldVerifySimple(const Descriptor* descriptor);
+
+bool IsUtf8String(const FieldDescriptor* field);
+
+bool HasMessageFieldOrExtension(const Descriptor* desc);
+
+}  // namespace cpp
+}  // namespace compiler
+}  // namespace protobuf
+}  // namespace google
+
+#include <google/protobuf/port_undef.inc>
+
+#endif  // GOOGLE_PROTOBUF_COMPILER_CPP_HELPERS_H__
diff --git a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_map_field.cc b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/map_field.cc
index 4d3e00ac89b..ba363f5267b 100644
--- a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_map_field.cc
+++ b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/map_field.cc
@@ -28,12 +28,12 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-#include <google/protobuf/compiler/cpp/cpp_map_field.h>
+#include <google/protobuf/compiler/cpp/map_field.h>
 
 #include <google/protobuf/io/printer.h>
 #include <google/protobuf/wire_format.h>
 #include <google/protobuf/stubs/strutil.h>
-#include <google/protobuf/compiler/cpp/cpp_helpers.h>
+#include <google/protobuf/compiler/cpp/helpers.h>
 
 
 namespace google {
@@ -136,6 +136,7 @@ void MapFieldGenerator::GenerateInlineAccessorDefinitions(
       "}\n"
       "inline ::$proto_ns$::Map< $key_cpp$, $val_cpp$ >*\n"
       "$classname$::_internal_mutable_$name$() {\n"
+      "$maybe_prepare_split_message$"
       "  return $field$.MutableMap();\n"
       "}\n"
       "inline ::$proto_ns$::Map< $key_cpp$, $val_cpp$ >*\n"
@@ -153,7 +154,7 @@ void MapFieldGenerator::GenerateClearingCode(io::Printer* printer) const {
 
 void MapFieldGenerator::GenerateMergingCode(io::Printer* printer) const {
   Formatter format(printer, variables_);
-  format("$field$.MergeFrom(from.$field$);\n");
+  format("_this->$field$.MergeFrom(from.$field$);\n");
 }
 
 void MapFieldGenerator::GenerateSwappingCode(io::Printer* printer) const {
@@ -226,8 +227,7 @@ void MapFieldGenerator::GenerateSerializeWithCachedSizesToArray(
             format);
       }
     }
-    format(
-        "};\n");
+    format("};\n");
   }
 
   format(
@@ -271,21 +271,48 @@ void MapFieldGenerator::GenerateIsInitialized(io::Printer* printer) const {
       "false;\n");
 }
 
-void MapFieldGenerator::GenerateConstinitInitializer(
+void MapFieldGenerator::GenerateConstexprAggregateInitializer(
     io::Printer* printer) const {
   Formatter format(printer, variables_);
   if (HasDescriptorMethods(descriptor_->file(), options_)) {
-    format("$name$_(::$proto_ns$::internal::ConstantInitialized{})");
+    format("/*decltype($field$)*/{::_pbi::ConstantInitialized()}");
   } else {
-    format("$name$_()");
+    format("/*decltype($field$)*/{}");
+  }
+}
+
+void MapFieldGenerator::GenerateCopyAggregateInitializer(
+    io::Printer* printer) const {
+  Formatter format(printer, variables_);
+  // MapField has no move constructor, which prevents explicit aggregate
+  // initialization pre-C++17.
+  format("/*decltype($field$)*/{}");
+}
+
+void MapFieldGenerator::GenerateAggregateInitializer(
+    io::Printer* printer) const {
+  Formatter format(printer, variables_);
+  if (ShouldSplit(descriptor_, options_)) {
+    format(
+        "/*decltype($classname$::Split::$name$_)*/"
+        "{::_pbi::ArenaInitialized(), arena}");
+    return;
   }
+  // MapField has no move constructor.
+  format("/*decltype($field$)*/{::_pbi::ArenaInitialized(), arena}");
 }
 
 void MapFieldGenerator::GenerateDestructorCode(io::Printer* printer) const {
   GOOGLE_CHECK(!IsFieldStripped(descriptor_, options_));
 
   Formatter format(printer, variables_);
+  if (ShouldSplit(descriptor_, options_)) {
+    format("$cached_split_ptr$->$name$_.Destruct();\n");
+    format("$cached_split_ptr$->$name$_.~MapField$lite$();\n");
+    return;
+  }
   format("$field$.Destruct();\n");
+  format("$field$.~MapField$lite$();\n");
 }
 
 void MapFieldGenerator::GenerateArenaDestructorCode(
diff --git a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_map_field.h b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/map_field.h
index 9e71267c0f1..678a128bd18 100644
--- a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_map_field.h
+++ b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/map_field.h
@@ -34,8 +34,8 @@
 #include <map>
 #include <string>
 
-#include <google/protobuf/compiler/cpp/cpp_helpers.h>
-#include <google/protobuf/compiler/cpp/cpp_message_field.h>
+#include <google/protobuf/compiler/cpp/helpers.h>
+#include <google/protobuf/compiler/cpp/message_field.h>
 
 namespace google {
 namespace protobuf {
@@ -61,7 +61,10 @@ class MapFieldGenerator : public FieldGenerator {
       io::Printer* printer) const override;
   void GenerateByteSize(io::Printer* printer) const override;
   void GenerateIsInitialized(io::Printer* printer) const override;
-  void GenerateConstinitInitializer(io::Printer* printer) const override;
+  void GenerateConstexprAggregateInitializer(
+      io::Printer* printer) const override;
+  void GenerateCopyAggregateInitializer(io::Printer* printer) const override;
+  void GenerateAggregateInitializer(io::Printer* printer) const override;
   void GenerateDestructorCode(io::Printer* printer) const override;
   void GenerateArenaDestructorCode(io::Printer* printer) const override;
   ArenaDtorNeeds NeedsArenaDestructor() const override;
diff --git a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_message.cc b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/message.cc
index a56c6fbda1e..77702a68dfc 100644
--- a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_message.cc
+++ b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/message.cc
@@ -32,7 +32,7 @@
 //  Based on original Protocol Buffers design by
 //  Sanjay Ghemawat, Jeff Dean, and others.
 
-#include <google/protobuf/compiler/cpp/cpp_message.h>
+#include <google/protobuf/compiler/cpp/message.h>
 
 #include <algorithm>
 #include <cstdint>
@@ -51,13 +51,14 @@
 #include <google/protobuf/map_entry_lite.h>
 #include <google/protobuf/wire_format.h>
 #include <google/protobuf/stubs/strutil.h>
+#include <google/protobuf/stubs/stringprintf.h>
 #include <google/protobuf/stubs/substitute.h>
-#include <google/protobuf/compiler/cpp/cpp_enum.h>
-#include <google/protobuf/compiler/cpp/cpp_extension.h>
-#include <google/protobuf/compiler/cpp/cpp_field.h>
-#include <google/protobuf/compiler/cpp/cpp_helpers.h>
-#include <google/protobuf/compiler/cpp/cpp_padding_optimizer.h>
-#include <google/protobuf/compiler/cpp/cpp_parse_function_generator.h>
+#include <google/protobuf/compiler/cpp/enum.h>
+#include <google/protobuf/compiler/cpp/extension.h>
+#include <google/protobuf/compiler/cpp/field.h>
+#include <google/protobuf/compiler/cpp/helpers.h>
+#include <google/protobuf/compiler/cpp/padding_optimizer.h>
+#include <google/protobuf/compiler/cpp/parse_function_generator.h>
 #include <google/protobuf/descriptor.pb.h>
 #include <google/protobuf/stubs/hash.h>
 
@@ -83,7 +84,7 @@ static constexpr int kNoHasbit = -1;
 // masks must be non-zero.
 TProtoStringType ConditionalToCheckBitmasks(
     const std::vector<arc_ui32>& masks, bool return_success = true,
-    StringPiece has_bits_var = "_has_bits_") {
+    StringPiece has_bits_var = "_impl_._has_bits_") {
   std::vector<TProtoStringType> parts;
   for (int i = 0; i < masks.size(); i++) {
     if (masks[i] == 0) continue;
@@ -345,10 +346,10 @@ bool IsRequired(const std::vector<const FieldDescriptor*>& v) {
   return v.front()->is_required();
 }
 
-bool HasSingularString(const Descriptor* desc, const Options& options) {
+bool HasNonSplitOptionalString(const Descriptor* desc, const Options& options) {
   for (const auto* field : FieldRange(desc)) {
     if (IsString(field, options) && !field->is_repeated() &&
-        !field->real_containing_oneof()) {
+        !field->real_containing_oneof() && !ShouldSplit(field, options)) {
       return true;
     }
   }
@@ -403,7 +404,7 @@ static int popcnt(arc_ui32 n) {
 class ColdChunkSkipper {
  public:
   ColdChunkSkipper(
-      const Options& options,
+      const Descriptor* descriptor, const Options& options,
       const std::vector<std::vector<const FieldDescriptor*>>& chunks,
       const std::vector<int>& has_bit_indices, const double cold_threshold)
       : chunks_(chunks),
@@ -411,7 +412,7 @@ class ColdChunkSkipper {
         access_info_map_(options.access_info_map),
         cold_threshold_(cold_threshold) {
     SetCommonVars(options, &variables_);
-    SetCommonMessageDataVariables(&variables_);
+    SetCommonMessageDataVariables(descriptor, &variables_);
   }
 
   // May open an external if check for a batch of cold fields. "from" is the
@@ -495,7 +496,7 @@ void ColdChunkSkipper::OnStartChunk(int chunk, int cached_has_word_index,
     if (this_word == cached_has_word_index) {
       format("(cached_has_bits & 0x$mask$u) != 0");
     } else {
-      format("($1$_has_bits_[$2$] & 0x$mask$u) != 0", from, this_word);
+      format("($1$_impl_._has_bits_[$2$] & 0x$mask$u) != 0", from, this_word);
     }
   }
   format(")) {\n");
@@ -547,9 +548,7 @@ void GenerateExtensionAnnotations(
   for (const auto& annotation : accessor_annotations_to_hooks) {
     (*variables)[annotation.first] = "";
   }
-  if (!options.field_listener_options.inject_field_listener_events ||
-      descriptor->file()->options().optimize_for() ==
-          google::protobuf::FileOptions::LITE_RUNTIME) {
+  if (!HasTracker(descriptor, options)) {
     return;
   }
   StringPiece tracker = (*variables)["tracker"];
@@ -617,7 +616,7 @@ MessageGenerator::MessageGenerator(
   if (!message_layout_helper_) {
     message_layout_helper_.reset(new PaddingOptimizer());
   }
-  SetCommonMessageDataVariables(&variables_);
+  SetCommonMessageDataVariables(descriptor, &variables_);
 
   // Variables that apply to this class
   variables_["classname"] = classname_;
@@ -630,9 +629,7 @@ MessageGenerator::MessageGenerator(
   variables_["annotate_bytesize"] = "";
   variables_["annotate_mergefrom"] = "";
 
-  if (options.field_listener_options.inject_field_listener_events &&
-      descriptor->file()->options().optimize_for() !=
-          google::protobuf::FileOptions::LITE_RUNTIME) {
+  if (HasTracker(descriptor_, options_)) {
     const TProtoStringType injector_template =
         StrCat("  ", variables_["tracker"], ".");
 
@@ -649,7 +646,7 @@ MessageGenerator::MessageGenerator(
     MaySetAnnotationVariable(options, "bytesize", injector_template,
                              "OnByteSize(this);\n", &variables_);
     MaySetAnnotationVariable(options, "mergefrom", injector_template,
-                             "OnMergeFrom(this, &from);\n", &variables_);
+                             "OnMergeFrom(_this, &from);\n", &variables_);
   }
 
   GenerateExtensionAnnotations(descriptor_, options_, &variables_);
@@ -1205,6 +1202,9 @@ void MessageGenerator::GenerateFieldClear(const FieldDescriptor* field,
     format.Outdent();
     format("}\n");
   } else {
+    if (ShouldSplit(field, options_)) {
+      format("if (IsSplitMessageDefault()) return;\n");
+    }
     field_generators_.get(field).GenerateClearingCode(format.printer());
     if (HasHasbit(field)) {
       int has_bit_index = HasBitIndex(field);
@@ -1245,13 +1245,12 @@ void MessageGenerator::GenerateFieldAccessorDefinitions(io::Printer* printer) {
       } else {
         format(
             "inline int $classname$::_internal_$name$_size() const {\n"
-            "  return $1$$2$.size();\n"
+            "  return $field$$1$.size();\n"
             "}\n"
             "inline int $classname$::$name$_size() const {\n"
             "$annotate_size$"
             "  return _internal_$name$_size();\n"
             "}\n",
-            FieldMemberName(field),
             IsImplicitWeakField(field, options_, scc_analyzer_) &&
                     field->message_type()
                 ? ".weak"
@@ -1398,6 +1397,11 @@ void MessageGenerator::GenerateClassDefinition(io::Printer* printer) {
     format(
         "inline $classname$() : $classname$("
         "::$proto_ns$::Arena::InternalCreateMessageOwnedArena(), true) {}\n");
+  } else if (EnableMessageOwnedArenaTrial(descriptor_, options_)) {
+    format(
+        "inline $classname$() : $classname$(InMoaTrial() ? "
+        "::$proto_ns$::Arena::InternalCreateMessageOwnedArena() : nullptr, "
+        "InMoaTrial()) {}\n");
   } else {
     format("inline $classname$() : $classname$(nullptr) {}\n");
   }
@@ -1510,11 +1514,13 @@ void MessageGenerator::GenerateClassDefinition(io::Printer* printer) {
     if (HasDescriptorMethods(descriptor_->file(), options_)) {
       format(
           "bool PackFrom(const ::$proto_ns$::Message& message) {\n"
+          "  $DCHK$_NE(&message, this);\n"
           "  return $any_metadata$.PackFrom(GetArena(), message);\n"
           "}\n"
           "bool PackFrom(const ::$proto_ns$::Message& message,\n"
           "              ::PROTOBUF_NAMESPACE_ID::ConstStringParam "
           "type_url_prefix) {\n"
+          "  $DCHK$_NE(&message, this);\n"
           "  return $any_metadata$.PackFrom(GetArena(), message, "
           "type_url_prefix);\n"
           "}\n"
@@ -1618,27 +1624,28 @@ void MessageGenerator::GenerateClassDefinition(io::Printer* printer) {
             // argument is a generic Message instance, and only define the
             // custom MergeFrom and CopyFrom instances when the source of the
             // merge/copy is known to be the same class as the destination.
-            // TODO(jorg): Define MergeFrom in terms of MergeImpl, rather than
-            // the other way around, to save even more code size.
             "using $superclass$::CopyFrom;\n"
             "void CopyFrom(const $classname$& from);\n"
             ""
             "using $superclass$::MergeFrom;\n"
-            "void MergeFrom(const $classname$& from);\n"
+            "void MergeFrom("
+            " const $classname$& from) {\n"
+            "  $classname$::MergeImpl(*this, from);\n"
+            "}\n"
             "private:\n"
-            "static void MergeImpl(::$proto_ns$::Message* to, const "
-            "::$proto_ns$::Message& from);\n"
+            "static void MergeImpl(::$proto_ns$::Message& to_msg, const "
+            "::$proto_ns$::Message& from_msg);\n"
             "public:\n");
       } else {
         format(
             "using $superclass$::CopyFrom;\n"
             "inline void CopyFrom(const $classname$& from) {\n"
-            "  $superclass$::CopyImpl(this, from);\n"
+            "  $superclass$::CopyImpl(*this, from);\n"
             "}\n"
             ""
             "using $superclass$::MergeFrom;\n"
             "void MergeFrom(const $classname$& from) {\n"
-            "  $superclass$::MergeImpl(this, from);\n"
+            "  $superclass$::MergeImpl(*this, from);\n"
             "}\n"
             "public:\n");
       }
@@ -1676,7 +1683,7 @@ void MessageGenerator::GenerateClassDefinition(io::Printer* printer) {
         "int GetCachedSize() const final { return "
         "$cached_size$.Get(); }"
         "\n\nprivate:\n"
-        "void SharedCtor();\n"
+        "void SharedCtor(::$proto_ns$::Arena* arena, bool is_message_owned);\n"
         "void SharedDtor();\n"
         "void SetCachedSize(int size) const$ full_final$;\n"
         "void InternalSwap($classname$* other);\n");
@@ -1747,6 +1754,17 @@ void MessageGenerator::GenerateClassDefinition(io::Printer* printer) {
         "\n");
   }
 
+  if (ShouldSplit(descriptor_, options_)) {
+    format(
+        "private:\n"
+        "inline bool IsSplitMessageDefault() const {\n"
+        "  return $split$ == reinterpret_cast<Impl_::Split*>(&$1$);\n"
+        "}\n"
+        "PROTOBUF_NOINLINE void PrepareSplitMessageForWrite();\n"
+        "public:\n",
+        DefaultInstanceName(descriptor_, options_, /*split=*/true));
+  }
+
   format(
       "// nested types ----------------------------------------------------\n"
       "\n");
@@ -1837,12 +1855,21 @@ void MessageGenerator::GenerateClassDefinition(io::Printer* printer) {
                            : StrCat("::$proto_ns$::internal::HasBits<",
                                           sizeof_has_bits, "> _has_bits_;\n");
 
+  format(
+      "template <typename T> friend class "
+      "::$proto_ns$::Arena::InternalHelper;\n"
+      "typedef void InternalArenaConstructable_;\n"
+      "typedef void DestructorSkippable_;\n");
+
   // To minimize padding, data members are divided into three sections:
   // (1) members assumed to align to 8 bytes
   // (2) members corresponding to message fields, re-ordered to optimize
   //     alignment.
   // (3) members assumed to align to 4 bytes.
 
+  format("struct Impl_ {\n");
+  format.Indent();
+
   // Members assumed to align to 8 bytes:
 
   if (descriptor_->extension_range_count() > 0) {
@@ -1851,9 +1878,7 @@ void MessageGenerator::GenerateClassDefinition(io::Printer* printer) {
         "\n");
   }
 
-  if (options_.field_listener_options.inject_field_listener_events &&
-      descriptor_->file()->options().optimize_for() !=
-          google::protobuf::FileOptions::LITE_RUNTIME) {
+  if (HasTracker(descriptor_, options_)) {
     format("static ::$proto_ns$::AccessListener<$1$> _tracker_;\n",
            ClassName(descriptor_));
   }
@@ -1866,12 +1891,6 @@ void MessageGenerator::GenerateClassDefinition(io::Printer* printer) {
            InlinedStringDonatedSize());
   }
 
-  format(
-      "template <typename T> friend class "
-      "::$proto_ns$::Arena::InternalHelper;\n"
-      "typedef void InternalArenaConstructable_;\n"
-      "typedef void DestructorSkippable_;\n");
-
   if (!has_bit_indices_.empty()) {
     // _has_bits_ is frequently accessed, so to reduce code size and improve
     // speed, it should be close to the start of the object. Placing
@@ -1890,7 +1909,24 @@ void MessageGenerator::GenerateClassDefinition(io::Printer* printer) {
   for (auto field : optimized_order_) {
     const FieldGenerator& generator = field_generators_.get(field);
     generator.GenerateStaticMembers(printer);
-    generator.GeneratePrivateMembers(printer);
+    if (!ShouldSplit(field, options_)) {
+      generator.GeneratePrivateMembers(printer);
+    }
+  }
+  if (ShouldSplit(descriptor_, options_)) {
+    format("struct Split {\n");
+    format.Indent();
+    for (auto field : optimized_order_) {
+      if (!ShouldSplit(field, options_)) continue;
+      const FieldGenerator& generator = field_generators_.get(field);
+      generator.GeneratePrivateMembers(printer);
+    }
+    format.Outdent();
+    format(
+        "  typedef void InternalArenaConstructable_;\n"
+        "  typedef void DestructorSkippable_;\n"
+        "};\n"
+        "Split* _split_;\n");
   }
 
   // For each oneof generate a union
@@ -1941,6 +1977,22 @@ void MessageGenerator::GenerateClassDefinition(io::Printer* printer) {
     format("::$proto_ns$::internal::AnyMetadata _any_metadata_;\n");
   }
 
+  format.Outdent();
+  format("};\n");
+
+  // Only create the _impl_ field if it contains data.
+  if (HasImplData(descriptor_, options_)) {
+    format("union { Impl_ _impl_; };\n");
+  }
+
+  if (ShouldSplit(descriptor_, options_)) {
+    format(
+        "static Impl_::Split* CreateSplitMessage("
+        "::$proto_ns$::Arena* arena);\n");
+    format("friend struct $1$;\n",
+           DefaultInstanceType(descriptor_, options_, /*split=*/true));
+  }
+
   // The TableStruct struct needs access to the private parts, in order to
   // construct the offsets of all members.
   format("friend struct ::$tablename$;\n");
@@ -2080,7 +2132,8 @@ void MessageGenerator::GenerateClassMethods(io::Printer* printer) {
   format("};\n\n");
   for (auto field : FieldRange(descriptor_)) {
     if (!IsFieldStripped(field, options_)) {
-      field_generators_.get(field).GenerateInternalAccessorDefinitions(printer);
+      field_generators_.get(field).GenerateInternalAccessorDefinitions(
+          printer);
     }
   }
 
@@ -2130,7 +2183,7 @@ void MessageGenerator::GenerateClassMethods(io::Printer* printer) {
     GenerateMergeFrom(printer);
     format("\n");
 
-    GenerateClassSpecificMergeFrom(printer);
+    GenerateClassSpecificMergeImpl(printer);
     format("\n");
 
     GenerateCopyFrom(printer);
@@ -2140,6 +2193,15 @@ void MessageGenerator::GenerateClassMethods(io::Printer* printer) {
     format("\n");
   }
 
+  if (ShouldSplit(descriptor_, options_)) {
+    format(
+        "void $classname$::PrepareSplitMessageForWrite() {\n"
+        "  if (IsSplitMessageDefault()) {\n"
+        "    $split$ = CreateSplitMessage(GetArenaForAllocation());\n"
+        "  }\n"
+        "}\n");
+  }
+
   GenerateVerify(printer);
 
   GenerateSwap(printer);
@@ -2172,9 +2234,7 @@ void MessageGenerator::GenerateClassMethods(io::Printer* printer) {
         "\n");
   }
 
-  if (options_.field_listener_options.inject_field_listener_events &&
-      descriptor_->file()->options().optimize_for() !=
-          google::protobuf::FileOptions::LITE_RUNTIME) {
+  if (HasTracker(descriptor_, options_)) {
     format(
         "::$proto_ns$::AccessListener<$classtype$> "
         "$1$::$tracker$(&FullMessageName);\n",
@@ -2230,7 +2290,11 @@ std::pair<size_t, size_t> MessageGenerator::GenerateOffsets(
       // Don't use the top bit because that is for unused fields.
       format("::_pbi::kInvalidFieldOffsetTag");
     } else {
-      format("PROTOBUF_FIELD_OFFSET($classtype$, $1$)", FieldMemberName(field));
+      format("PROTOBUF_FIELD_OFFSET($classtype$$1$, $2$)",
+             ShouldSplit(field, options_) ? "::Impl_::Split" : "",
+             ShouldSplit(field, options_)
+                 ? FieldName(field) + "_"
+                 : FieldMemberName(field, /*cold=*/false));
     }
 
     // Some information about a field is in the pdproto profile. The profile is
@@ -2250,7 +2314,7 @@ std::pair<size_t, size_t> MessageGenerator::GenerateOffsets(
 
   int count = 0;
   for (auto oneof : OneOfRange(descriptor_)) {
-    format("PROTOBUF_FIELD_OFFSET($classtype$, $1$_),\n", oneof->name());
+    format("PROTOBUF_FIELD_OFFSET($classtype$, _impl_.$1$_),\n", oneof->name());
     count++;
   }
   GOOGLE_CHECK_EQ(count, descriptor_->real_oneof_decl_count());
@@ -2286,18 +2350,181 @@ void MessageGenerator::GenerateSharedConstructorCode(io::Printer* printer) {
   if (HasSimpleBaseClass(descriptor_, options_)) return;
   Formatter format(printer, variables_);
 
-  format("inline void $classname$::SharedCtor() {\n");
+  format(
+      "inline void $classname$::SharedCtor(\n"
+      "    ::_pb::Arena* arena, bool is_message_owned) {\n"
+      "  (void)arena;\n"
+      "  (void)is_message_owned;\n");
 
-  std::vector<bool> processed(optimized_order_.size(), false);
-  GenerateConstructorBody(printer, processed, false);
+  format.Indent();
+  // Impl_ _impl_.
+  format("new (&_impl_) Impl_{");
+  format.Indent();
+  const char* field_sep = " ";
+  const auto put_sep = [&] {
+    format("\n$1$ ", field_sep);
+    field_sep = ",";
+  };
+
+  // Note: any fields without move/copy constructors can't be explicitly
+  // aggregate initialized pre-C++17.
+  if (descriptor_->extension_range_count() > 0) {
+    put_sep();
+    format("/*decltype($extensions$)*/{::_pbi::ArenaInitialized(), arena}");
+  }
+  if (!inlined_string_indices_.empty()) {
+    put_sep();
+    format("decltype($inlined_string_donated_array$){}");
+  }
+  bool need_to_emit_cached_size = !HasSimpleBaseClass(descriptor_, options_);
+  if (!has_bit_indices_.empty()) {
+    put_sep();
+    format("decltype($has_bits$){}");
+    if (need_to_emit_cached_size) {
+      put_sep();
+      format("/*decltype($cached_size$)*/{}");
+      need_to_emit_cached_size = false;
+    }
+  }
+
+  // Initialize member variables with arena constructor.
+  for (auto field : optimized_order_) {
+    GOOGLE_DCHECK(!IsFieldStripped(field, options_));
+    if (ShouldSplit(field, options_)) {
+      continue;
+    }
+    put_sep();
+    field_generators_.get(field).GenerateAggregateInitializer(printer);
+  }
+  if (ShouldSplit(descriptor_, options_)) {
+    put_sep();
+    format("decltype($split$){reinterpret_cast<Impl_::Split*>(&$1$)}",
+           DefaultInstanceName(descriptor_, options_, /*split=*/true));
+  }
+  for (auto oneof : OneOfRange(descriptor_)) {
+    put_sep();
+    format("decltype(_impl_.$1$_){}", oneof->name());
+  }
+
+  if (need_to_emit_cached_size) {
+    put_sep();
+    format("/*decltype($cached_size$)*/{}");
+  }
+
+  if (descriptor_->real_oneof_decl_count() != 0) {
+    put_sep();
+    format("/*decltype($oneof_case$)*/{}");
+  }
+  if (num_weak_fields_ > 0) {
+    put_sep();
+    format("decltype($weak_field_map$){arena}");
+  }
+  if (IsAnyMessage(descriptor_, options_)) {
+    put_sep();
+    // AnyMetadata has no move constructor.
+    format("/*decltype($any_metadata$)*/{&_impl_.type_url_, &_impl_.value_}");
+  }
+
+  format.Outdent();
+  format("\n};\n");
+
+  if (!inlined_string_indices_.empty()) {
+    // Donate inline string fields.
+    format.Indent();
+    // The last bit is the tracking bit for registering ArenaDtor. The bit is 1
+    // means ArenaDtor is not registered on construction, and on demand register
+    // is needed.
+    format("if (arena != nullptr) {\n");
+    if (NeedsArenaDestructor() == ArenaDtorNeeds::kOnDemand) {
+      format(
+          "  if (!is_message_owned) {\n"
+          "    $inlined_string_donated_array$[0] = ~0u;\n"
+          "  } else {\n"
+          // We should not register ArenaDtor for MOA.
+          "    $inlined_string_donated_array$[0] = 0xFFFFFFFEu;\n"
+          "  }\n");
+    } else {
+      format("  $inlined_string_donated_array$[0] = 0xFFFFFFFEu;\n");
+    }
+    for (size_t i = 1; i < InlinedStringDonatedSize(); ++i) {
+      format("  $inlined_string_donated_array$[$1$] = ~0u;\n", i);
+    }
+    format("}\n");
+    format.Outdent();
+  }
+
+  for (const FieldDescriptor* field : optimized_order_) {
+    if (ShouldSplit(field, options_)) {
+      continue;
+    }
+    field_generators_.get(field).GenerateConstructorCode(printer);
+  }
 
   for (auto oneof : OneOfRange(descriptor_)) {
     format("clear_has_$1$();\n", oneof->name());
   }
 
+  format.Outdent();
   format("}\n\n");
 }
 
+void MessageGenerator::GenerateCreateSplitMessage(io::Printer* printer) {
+  Formatter format(printer, variables_);
+  format(
+      "$classname$::Impl_::Split* "
+      "$classname$::CreateSplitMessage(::$proto_ns$::Arena* arena) {\n");
+  format.Indent();
+  const char* field_sep = " ";
+  const auto put_sep = [&] {
+    format("\n$1$ ", field_sep);
+    field_sep = ",";
+  };
+  format(
+      "const size_t size = sizeof(Impl_::Split);\n"
+      "void* chunk = (arena == nullptr) ?\n"
+      "  ::operator new(size) :\n"
+      "  arena->AllocateAligned(size, alignof(Impl_::Split));\n"
+      "Impl_::Split* ptr = reinterpret_cast<Impl_::Split*>(chunk);\n"
+      "new (ptr) Impl_::Split{");
+  format.Indent();
+  for (const FieldDescriptor* field : optimized_order_) {
+    GOOGLE_DCHECK(!IsFieldStripped(field, options_));
+    if (ShouldSplit(field, options_)) {
+      put_sep();
+      field_generators_.get(field).GenerateAggregateInitializer(printer);
+    }
+  }
+  format.Outdent();
+  format("};\n");
+  for (const FieldDescriptor* field : optimized_order_) {
+    GOOGLE_DCHECK(!IsFieldStripped(field, options_));
+    if (ShouldSplit(field, options_)) {
+      field_generators_.get(field).GenerateCreateSplitMessageCode(printer);
+    }
+  }
+  format("return ptr;\n");
+  format.Outdent();
+  format("}\n");
+}
+
+void MessageGenerator::GenerateInitDefaultSplitInstance(io::Printer* printer) {
+  if (!ShouldSplit(descriptor_, options_)) return;
+
+  Formatter format(printer, variables_);
+  const char* field_sep = " ";
+  const auto put_sep = [&] {
+    format("\n$1$ ", field_sep);
+    field_sep = ",";
+  };
+  for (const auto* field : optimized_order_) {
+    if (ShouldSplit(field, options_)) {
+      put_sep();
+      field_generators_.get(field).GenerateConstexprAggregateInitializer(
+          printer);
+    }
+  }
+}
+
 void MessageGenerator::GenerateSharedDestructorCode(io::Printer* printer) {
   if (HasSimpleBaseClass(descriptor_, options_)) return;
   Formatter format(printer, variables_);
@@ -2305,11 +2532,32 @@ void MessageGenerator::GenerateSharedDestructorCode(io::Printer* printer) {
   format("inline void $classname$::SharedDtor() {\n");
   format.Indent();
   format("$DCHK$(GetArenaForAllocation() == nullptr);\n");
+
+  if (descriptor_->extension_range_count() > 0) {
+    format("$extensions$.~ExtensionSet();\n");
+  }
+
   // Write the destructors for each field except oneof members.
   // optimized_order_ does not contain oneof fields.
   for (auto field : optimized_order_) {
+    if (ShouldSplit(field, options_)) {
+      continue;
+    }
     field_generators_.get(field).GenerateDestructorCode(printer);
   }
+  if (ShouldSplit(descriptor_, options_)) {
+    format("if (!IsSplitMessageDefault()) {\n");
+    format.Indent();
+    format("auto* $cached_split_ptr$ = $split$;\n");
+    for (auto field : optimized_order_) {
+      if (ShouldSplit(field, options_)) {
+        field_generators_.get(field).GenerateDestructorCode(printer);
+      }
+    }
+    format("delete $cached_split_ptr$;\n");
+    format.Outdent();
+    format("}\n");
+  }
 
   // Generate code to destruct oneofs. Clearing should do the work.
   for (auto oneof : OneOfRange(descriptor_)) {
@@ -2323,6 +2571,11 @@ void MessageGenerator::GenerateSharedDestructorCode(io::Printer* printer) {
   if (num_weak_fields_) {
     format("$weak_field_map$.ClearAll();\n");
   }
+
+  if (IsAnyMessage(descriptor_, options_)) {
+    format("$any_metadata$.~AnyMetadata();\n");
+  }
+
   format.Outdent();
   format(
       "}\n"
@@ -2358,10 +2611,23 @@ void MessageGenerator::GenerateArenaDestructorCode(io::Printer* printer) {
 
   // Process non-oneof fields first.
   for (auto field : optimized_order_) {
-    if (IsFieldStripped(field, options_)) continue;
+    if (IsFieldStripped(field, options_) || ShouldSplit(field, options_))
+      continue;
     const FieldGenerator& fg = field_generators_.get(field);
     fg.GenerateArenaDestructorCode(printer);
   }
+  if (ShouldSplit(descriptor_, options_)) {
+    format("if (!_this->IsSplitMessageDefault()) {\n");
+    format.Indent();
+    for (auto field : optimized_order_) {
+      if (IsFieldStripped(field, options_) || !ShouldSplit(field, options_))
+        continue;
+      const FieldGenerator& fg = field_generators_.get(field);
+      fg.GenerateArenaDestructorCode(printer);
+    }
+    format.Outdent();
+    format("}\n");
+  }
 
   // Process oneof fields.
   for (auto oneof : OneOfRange(descriptor_)) {
@@ -2378,72 +2644,118 @@ void MessageGenerator::GenerateArenaDestructorCode(io::Printer* printer) {
 void MessageGenerator::GenerateConstexprConstructor(io::Printer* printer) {
   Formatter format(printer, variables_);
 
+  if (IsMapEntryMessage(descriptor_) || !HasImplData(descriptor_, options_)) {
+    format(
+        "PROTOBUF_CONSTEXPR $classname$::$classname$(\n"
+        "    ::_pbi::ConstantInitialized) {}\n");
+    return;
+  }
+
   format(
       "PROTOBUF_CONSTEXPR $classname$::$classname$(\n"
       "    ::_pbi::ConstantInitialized)");
+
+  bool need_to_emit_cached_size = !HasSimpleBaseClass(descriptor_, options_);
+  format(": _impl_{");
   format.Indent();
-  const char* field_sep = ":";
+  const char* field_sep = " ";
   const auto put_sep = [&] {
     format("\n$1$ ", field_sep);
     field_sep = ",";
   };
-
-  if (!IsMapEntryMessage(descriptor_)) {
-    // Process non-oneof fields first.
-    for (auto field : optimized_order_) {
-      auto& gen = field_generators_.get(field);
+  if (descriptor_->extension_range_count() > 0) {
+    put_sep();
+    format("/*decltype($extensions$)*/{}");
+  }
+  if (!inlined_string_indices_.empty()) {
+    put_sep();
+    format("/*decltype($inlined_string_donated_array$)*/{}");
+  }
+  if (!has_bit_indices_.empty()) {
+    put_sep();
+    format("/*decltype($has_bits$)*/{}");
+    if (need_to_emit_cached_size) {
       put_sep();
-      gen.GenerateConstinitInitializer(printer);
+      format("/*decltype($cached_size$)*/{}");
+      need_to_emit_cached_size = false;
     }
-
-    if (IsAnyMessage(descriptor_, options_)) {
-      put_sep();
-      format("_any_metadata_(&type_url_, &value_)");
+  }
+  for (auto field : optimized_order_) {
+    if (ShouldSplit(field, options_)) {
+      continue;
     }
+    put_sep();
+    field_generators_.get(field).GenerateConstexprAggregateInitializer(
+        printer);
+  }
+  if (ShouldSplit(descriptor_, options_)) {
+    put_sep();
+    format("/*decltype($split$)*/&$1$._instance",
+           DefaultInstanceName(descriptor_, options_, /*split=*/true));
+  }
 
-    if (descriptor_->real_oneof_decl_count() != 0) {
-      put_sep();
-      format("_oneof_case_{}");
-    }
+  for (auto oneof : OneOfRange(descriptor_)) {
+    put_sep();
+    format("/*decltype(_impl_.$1$_)*/{}", oneof->name());
+  }
+
+  if (need_to_emit_cached_size) {
+    put_sep();
+    format("/*decltype($cached_size$)*/{}");
+  }
+
+  if (descriptor_->real_oneof_decl_count() != 0) {
+    put_sep();
+    format("/*decltype($oneof_case$)*/{}");
+  }
+
+  if (num_weak_fields_) {
+    put_sep();
+    format("/*decltype($weak_field_map$)*/{}");
+  }
+
+  if (IsAnyMessage(descriptor_, options_)) {
+    put_sep();
+    format(
+        "/*decltype($any_metadata$)*/{&_impl_.type_url_, "
+        "&_impl_.value_}");
   }
 
   format.Outdent();
-  format("{}\n");
+  format("} {}\n");
 }
 
-void MessageGenerator::GenerateConstructorBody(io::Printer* printer,
-                                               std::vector<bool> processed,
-                                               bool copy_constructor) const {
+void MessageGenerator::GenerateCopyConstructorBody(io::Printer* printer) const {
   Formatter format(printer, variables_);
 
-  const RunMap runs = FindRuns(
-      optimized_order_, [copy_constructor, this](const FieldDescriptor* field) {
-        return (copy_constructor && IsPOD(field)) ||
-               (!copy_constructor &&
-                CanBeManipulatedAsRawBytes(field, options_, scc_analyzer_));
+  const RunMap runs =
+      FindRuns(optimized_order_, [this](const FieldDescriptor* field) {
+        return IsPOD(field) && !ShouldSplit(field, options_);
       });
 
-  TProtoStringType pod_template;
-  if (copy_constructor) {
-    pod_template =
-        "::memcpy(&$first$, &from.$first$,\n"
-        "  static_cast<size_t>(reinterpret_cast<char*>(&$last$) -\n"
-        "  reinterpret_cast<char*>(&$first$)) + sizeof($last$));\n";
-  } else {
-    pod_template =
-        "::memset(reinterpret_cast<char*>(this) + static_cast<size_t>(\n"
-        "    reinterpret_cast<char*>(&$first$) - "
-        "reinterpret_cast<char*>(this)),\n"
-        "    0, static_cast<size_t>(reinterpret_cast<char*>(&$last$) -\n"
-        "    reinterpret_cast<char*>(&$first$)) + sizeof($last$));\n";
-  }
+  TProtoStringType pod_template =
+      "::memcpy(&$first$, &from.$first$,\n"
+      "  static_cast<size_t>(reinterpret_cast<char*>(&$last$) -\n"
+      "  reinterpret_cast<char*>(&$first$)) + sizeof($last$));\n";
 
-  for (int i = 0; i < optimized_order_.size(); ++i) {
-    if (processed[i]) {
-      continue;
+  if (ShouldSplit(descriptor_, options_)) {
+    format("if (!from.IsSplitMessageDefault()) {\n");
+    format.Indent();
+    format("_this->PrepareSplitMessageForWrite();\n");
+    for (auto field : optimized_order_) {
+      if (ShouldSplit(field, options_)) {
+        field_generators_.get(field).GenerateCopyConstructorCode(printer);
+      }
     }
+    format.Outdent();
+    format("}\n");
+  }
 
+  for (size_t i = 0; i < optimized_order_.size(); ++i) {
     const FieldDescriptor* field = optimized_order_[i];
+    if (ShouldSplit(field, options_)) {
+      continue;
+    }
     const auto it = runs.find(field);
 
     // We only apply the memset technique to runs of more than one field, as
@@ -2451,9 +2763,10 @@ void MessageGenerator::GenerateConstructorBody(io::Printer* printer,
     if (it != runs.end() && it->second > 1) {
       // Use a memset, then skip run_length fields.
       const size_t run_length = it->second;
-      const TProtoStringType first_field_name = FieldMemberName(field);
+      const TProtoStringType first_field_name =
+          FieldMemberName(field, /*cold=*/false);
       const TProtoStringType last_field_name =
-          FieldMemberName(optimized_order_[i + run_length - 1]);
+          FieldMemberName(optimized_order_[i + run_length - 1], /*cold=*/false);
 
       format.Set("first", first_field_name);
       format.Set("last", last_field_name);
@@ -2463,11 +2776,7 @@ void MessageGenerator::GenerateConstructorBody(io::Printer* printer,
       i += run_length - 1;
       // ++i at the top of the loop.
     } else {
-      if (copy_constructor) {
-        field_generators_.get(field).GenerateCopyConstructorCode(printer);
-      } else {
-        field_generators_.get(field).GenerateConstructorCode(printer);
-      }
+      field_generators_.get(field).GenerateCopyConstructorCode(printer);
     }
   }
 }
@@ -2475,78 +2784,14 @@ void MessageGenerator::GenerateConstructorBody(io::Printer* printer,
 void MessageGenerator::GenerateStructors(io::Printer* printer) {
   Formatter format(printer, variables_);
 
-  TProtoStringType superclass;
-  superclass = SuperClassName(descriptor_, options_);
-  TProtoStringType initializer_with_arena = superclass + "(arena, is_message_owned)";
-
-  if (descriptor_->extension_range_count() > 0) {
-    initializer_with_arena += ",\n  _extensions_(arena)";
-  }
-
-  // Initialize member variables with arena constructor.
-  for (auto field : optimized_order_) {
-    GOOGLE_DCHECK(!IsFieldStripped(field, options_));
-    bool has_arena_constructor = field->is_repeated();
-    if (!field->real_containing_oneof() &&
-        (IsLazy(field, options_, scc_analyzer_) ||
-         IsStringPiece(field, options_) ||
-         (IsString(field, options_) && IsStringInlined(field, options_)))) {
-      has_arena_constructor = true;
-    }
-    if (has_arena_constructor) {
-      initializer_with_arena +=
-          TProtoStringType(",\n  ") + FieldName(field) + TProtoStringType("_(arena)");
-    }
-  }
-
-  if (IsAnyMessage(descriptor_, options_)) {
-    initializer_with_arena += ",\n  _any_metadata_(&type_url_, &value_)";
-  }
-  if (num_weak_fields_ > 0) {
-    initializer_with_arena += ", _weak_field_map_(arena)";
-  }
-
-  TProtoStringType initializer_null = superclass + "()";
-  if (IsAnyMessage(descriptor_, options_)) {
-    initializer_null += ", _any_metadata_(&type_url_, &value_)";
-  }
-  if (num_weak_fields_ > 0) {
-    initializer_null += ", _weak_field_map_(nullptr)";
-  }
-
   format(
       "$classname$::$classname$(::$proto_ns$::Arena* arena,\n"
       "                         bool is_message_owned)\n"
-      "  : $1$ {\n",
-      initializer_with_arena);
-
-  if (!inlined_string_indices_.empty()) {
-    // Donate inline string fields.
-    format.Indent();
-    // The last bit is the tracking bit for registering ArenaDtor. The bit is 1
-    // means ArenaDtor is not registered on construction, and on demand register
-    // is needed.
-    format("if (arena != nullptr) {\n");
-    if (NeedsArenaDestructor() == ArenaDtorNeeds::kOnDemand) {
-      format(
-          "  if (!is_message_owned) {\n"
-          "    $inlined_string_donated_array$[0] = ~0u;\n"
-          "  } else {\n"
-          // We should not register ArenaDtor for MOA.
-          "    $inlined_string_donated_array$[0] = 0xFFFFFFFEu;\n"
-          "  }\n");
-    } else {
-      format("  $inlined_string_donated_array$[0] = 0xFFFFFFFEu;\n");
-    }
-    for (size_t i = 1; i < InlinedStringDonatedSize(); ++i) {
-      format("  $inlined_string_donated_array$[$1$] = ~0u;\n", i);
-    }
-    format("}\n");
-    format.Outdent();
-  }
+      "  : $1$(arena, is_message_owned) {\n",
+      SuperClassName(descriptor_, options_));
 
   if (!HasSimpleBaseClass(descriptor_, options_)) {
-    format("  SharedCtor();\n");
+    format("  SharedCtor(arena, is_message_owned);\n");
     if (NeedsArenaDestructor() == ArenaDtorNeeds::kRequired) {
       format(
           "  if (arena != nullptr && !is_message_owned) {\n"
@@ -2576,40 +2821,81 @@ void MessageGenerator::GenerateStructors(io::Printer* printer) {
   } else {
     format(
         "$classname$::$classname$(const $classname$& from)\n"
-        "  : $superclass$()");
-    format.Indent();
-    format.Indent();
+        "  : $superclass$() {\n");
     format.Indent();
+    format("$classname$* const _this = this; (void)_this;\n");
 
-    // Do not copy inlined_string_donated_, because this is not an arena
-    // constructor.
+    if (HasImplData(descriptor_, options_)) {
+      const char* field_sep = " ";
+      const auto put_sep = [&] {
+        format("\n$1$ ", field_sep);
+        field_sep = ",";
+      };
 
-    if (!has_bit_indices_.empty()) {
-      format(",\n_has_bits_(from._has_bits_)");
-    }
+      format("new (&_impl_) Impl_{");
+      format.Indent();
 
-    std::vector<bool> processed(optimized_order_.size(), false);
-    for (int i = 0; i < optimized_order_.size(); i++) {
-      auto field = optimized_order_[i];
-      if (!(field->is_repeated() && !(field->is_map())) &&
-          !IsCord(field, options_)) {
-        continue;
+      if (descriptor_->extension_range_count() > 0) {
+        put_sep();
+        format("/*decltype($extensions$)*/{}");
+      }
+      if (!inlined_string_indices_.empty()) {
+        // Do not copy inlined_string_donated_, because this is not an arena
+        // constructor.
+        put_sep();
+        format("decltype($inlined_string_donated_array$){}");
+      }
+      bool need_to_emit_cached_size =
+          !HasSimpleBaseClass(descriptor_, options_);
+      if (!has_bit_indices_.empty()) {
+        put_sep();
+        format("decltype($has_bits$){from.$has_bits$}");
+        if (need_to_emit_cached_size) {
+          put_sep();
+          format("/*decltype($cached_size$)*/{}");
+          need_to_emit_cached_size = false;
+        }
       }
 
-      processed[i] = true;
-      format(",\n$1$_(from.$1$_)", FieldName(field));
-    }
+      // Initialize member variables with arena constructor.
+      for (auto field : optimized_order_) {
+        if (ShouldSplit(field, options_)) {
+          continue;
+        }
+        put_sep();
+        field_generators_.get(field).GenerateCopyAggregateInitializer(printer);
+      }
+      if (ShouldSplit(descriptor_, options_)) {
+        put_sep();
+        format("decltype($split$){reinterpret_cast<Impl_::Split*>(&$1$)}",
+               DefaultInstanceName(descriptor_, options_, /*split=*/true));
+      }
+      for (auto oneof : OneOfRange(descriptor_)) {
+        put_sep();
+        format("decltype(_impl_.$1$_){}", oneof->name());
+      }
 
-    if (IsAnyMessage(descriptor_, options_)) {
-      format(",\n_any_metadata_(&type_url_, &value_)");
-    }
-    if (num_weak_fields_ > 0) {
-      format(",\n_weak_field_map_(from._weak_field_map_)");
-    }
+      if (need_to_emit_cached_size) {
+        put_sep();
+        format("/*decltype($cached_size$)*/{}");
+      }
 
-    format.Outdent();
-    format.Outdent();
-    format(" {\n");
+      if (descriptor_->real_oneof_decl_count() != 0) {
+        put_sep();
+        format("/*decltype($oneof_case$)*/{}");
+      }
+      if (num_weak_fields_ > 0) {
+        put_sep();
+        format("decltype($weak_field_map$){from.$weak_field_map$}");
+      }
+      if (IsAnyMessage(descriptor_, options_)) {
+        put_sep();
+        format(
+            "/*decltype($any_metadata$)*/{&_impl_.type_url_, &_impl_.value_}");
+      }
+      format.Outdent();
+      format("};\n\n");
+    }
 
     format(
         "_internal_metadata_.MergeFrom<$unknown_fields_type$>(from._internal_"
@@ -2621,7 +2907,7 @@ void MessageGenerator::GenerateStructors(io::Printer* printer) {
           "from.$extensions$);\n");
     }
 
-    GenerateConstructorBody(printer, processed, true);
+    GenerateCopyConstructorBody(printer);
 
     // Copy oneof fields. Oneof field requires oneof case check.
     for (auto oneof : OneOfRange(descriptor_)) {
@@ -2659,6 +2945,10 @@ void MessageGenerator::GenerateStructors(io::Printer* printer) {
   // Generate the shared constructor code.
   GenerateSharedConstructorCode(printer);
 
+  if (ShouldSplit(descriptor_, options_)) {
+    GenerateCreateSplitMessage(printer);
+  }
+
   // Generate the destructor.
   if (!HasSimpleBaseClass(descriptor_, options_)) {
     format(
@@ -2756,6 +3046,7 @@ void MessageGenerator::GenerateClear(io::Printer* printer) {
         // (memset) per chunk, and if present it will be at the beginning.
         bool same = HasByteIndex(a) == HasByteIndex(b) &&
                     a->is_repeated() == b->is_repeated() &&
+                    ShouldSplit(a, options_) == ShouldSplit(b, options_) &&
                     (CanInitializeByZeroing(a) == CanInitializeByZeroing(b) ||
                      (CanInitializeByZeroing(a) &&
                       (chunk_count == 1 || merge_zero_init)));
@@ -2763,7 +3054,8 @@ void MessageGenerator::GenerateClear(io::Printer* printer) {
         return same;
       });
 
-  ColdChunkSkipper cold_skipper(options_, chunks, has_bit_indices_, kColdRatio);
+  ColdChunkSkipper cold_skipper(descriptor_, options_, chunks, has_bit_indices_,
+                                kColdRatio);
   int cached_has_word_index = -1;
 
   for (int chunk_index = 0; chunk_index < chunks.size(); chunk_index++) {
@@ -2773,7 +3065,7 @@ void MessageGenerator::GenerateClear(io::Printer* printer) {
     const FieldDescriptor* memset_start = nullptr;
     const FieldDescriptor* memset_end = nullptr;
     bool saw_non_zero_init = false;
-
+    bool chunk_is_cold = !chunk.empty() && ShouldSplit(chunk.front(), options_);
     for (const auto& field : chunk) {
       if (CanInitializeByZeroing(field)) {
         GOOGLE_CHECK(!saw_non_zero_init);
@@ -2813,17 +3105,25 @@ void MessageGenerator::GenerateClear(io::Printer* printer) {
       format.Indent();
     }
 
+    if (chunk_is_cold) {
+      format("if (!IsSplitMessageDefault()) {\n");
+      format.Indent();
+    }
+
     if (memset_start) {
       if (memset_start == memset_end) {
         // For clarity, do not memset a single field.
         field_generators_.get(memset_start)
             .GenerateMessageClearingCode(printer);
       } else {
+        GOOGLE_CHECK_EQ(chunk_is_cold, ShouldSplit(memset_start, options_));
+        GOOGLE_CHECK_EQ(chunk_is_cold, ShouldSplit(memset_end, options_));
         format(
             "::memset(&$1$, 0, static_cast<size_t>(\n"
             "    reinterpret_cast<char*>(&$2$) -\n"
             "    reinterpret_cast<char*>(&$1$)) + sizeof($2$));\n",
-            FieldMemberName(memset_start), FieldMemberName(memset_end));
+            FieldMemberName(memset_start, chunk_is_cold),
+            FieldMemberName(memset_end, chunk_is_cold));
       }
     }
 
@@ -2852,6 +3152,11 @@ void MessageGenerator::GenerateClear(io::Printer* printer) {
       }
     }
 
+    if (chunk_is_cold) {
+      format.Outdent();
+      format("}\n");
+    }
+
     if (have_outer_if) {
       format.Outdent();
       format("}\n");
@@ -2950,7 +3255,7 @@ void MessageGenerator::GenerateSwap(io::Printer* printer) {
     std::map<TProtoStringType, TProtoStringType> vars;
     SetUnknownFieldsVariable(descriptor_, options_, &vars);
     format.AddMap(vars);
-    if (HasSingularString(descriptor_, options_)) {
+    if (HasNonSplitOptionalString(descriptor_, options_)) {
       format(
           "auto* lhs_arena = GetArenaForAllocation();\n"
           "auto* rhs_arena = other->GetArenaForAllocation();\n");
@@ -2966,11 +3271,15 @@ void MessageGenerator::GenerateSwap(io::Printer* printer) {
     // If possible, we swap several fields at once, including padding.
     const RunMap runs =
         FindRuns(optimized_order_, [this](const FieldDescriptor* field) {
-          return CanBeManipulatedAsRawBytes(field, options_, scc_analyzer_);
+          return !ShouldSplit(field, options_) &&
+                 CanBeManipulatedAsRawBytes(field, options_, scc_analyzer_);
         });
 
-    for (int i = 0; i < optimized_order_.size(); ++i) {
+    for (size_t i = 0; i < optimized_order_.size(); ++i) {
       const FieldDescriptor* field = optimized_order_[i];
+      if (ShouldSplit(field, options_)) {
+        continue;
+      }
       const auto it = runs.find(field);
 
       // We only apply the memswap technique to runs of more than one field, as
@@ -2979,9 +3288,10 @@ void MessageGenerator::GenerateSwap(io::Printer* printer) {
       if (it != runs.end() && it->second > 1) {
         // Use a memswap, then skip run_length fields.
         const size_t run_length = it->second;
-        const TProtoStringType first_field_name = FieldMemberName(field);
-        const TProtoStringType last_field_name =
-            FieldMemberName(optimized_order_[i + run_length - 1]);
+        const TProtoStringType first_field_name =
+            FieldMemberName(field, /*cold=*/false);
+        const TProtoStringType last_field_name = FieldMemberName(
+            optimized_order_[i + run_length - 1], /*cold=*/false);
 
         format.Set("first", first_field_name);
         format.Set("last", last_field_name);
@@ -3000,16 +3310,16 @@ void MessageGenerator::GenerateSwap(io::Printer* printer) {
         field_generators_.get(field).GenerateSwappingCode(printer);
       }
     }
+    if (ShouldSplit(descriptor_, options_)) {
+      format("swap($split$, other->$split$);\n");
+    }
 
     for (auto oneof : OneOfRange(descriptor_)) {
-      format("swap($1$_, other->$1$_);\n", oneof->name());
+      format("swap(_impl_.$1$_, other->_impl_.$1$_);\n", oneof->name());
     }
 
     for (int i = 0; i < descriptor_->real_oneof_decl_count(); i++) {
-      format(
-          "swap($oneof_case$[$1$], "
-          "other->$oneof_case$[$1$]);\n",
-          i);
+      format("swap($oneof_case$[$1$], other->$oneof_case$[$1$]);\n", i);
     }
 
     if (num_weak_fields_) {
@@ -3050,17 +3360,11 @@ void MessageGenerator::GenerateMergeFrom(io::Printer* printer) {
       format(
           "const ::$proto_ns$::Message::ClassData "
           "$classname$::_class_data_ = {\n"
-          "    ::$proto_ns$::Message::CopyWithSizeCheck,\n"
+          "    ::$proto_ns$::Message::CopyWithSourceCheck,\n"
           "    $classname$::MergeImpl\n"
           "};\n"
           "const ::$proto_ns$::Message::ClassData*"
           "$classname$::GetClassData() const { return &_class_data_; }\n"
-          "\n"
-          "void $classname$::MergeImpl(::$proto_ns$::Message* to,\n"
-          "                      const ::$proto_ns$::Message& from) {\n"
-          "  static_cast<$classname$ *>(to)->MergeFrom(\n"
-          "      static_cast<const $classname$ &>(from));\n"
-          "}\n"
           "\n");
     } else {
       // Generate CheckTypeAndMergeFrom().
@@ -3087,29 +3391,50 @@ void MessageGenerator::GenerateMergeFrom(io::Printer* printer) {
   }
 }
 
-void MessageGenerator::GenerateClassSpecificMergeFrom(io::Printer* printer) {
+void MessageGenerator::GenerateClassSpecificMergeImpl(io::Printer* printer) {
   if (HasSimpleBaseClass(descriptor_, options_)) return;
   // Generate the class-specific MergeFrom, which avoids the GOOGLE_CHECK and cast.
   Formatter format(printer, variables_);
+  if (!HasDescriptorMethods(descriptor_->file(), options_)) {
+    // For messages that don't inherit from Message, just implement MergeFrom
+    // directly.
+    format(
+        "void $classname$::MergeFrom(const $classname$& from) {\n"
+        "  $classname$* const _this = this;\n");
+  } else {
+    format(
+        "void $classname$::MergeImpl(::$proto_ns$::Message& to_msg, const "
+        "::$proto_ns$::Message& from_msg) {\n"
+        "  auto* const _this = static_cast<$classname$*>(&to_msg);\n"
+        "  auto& from = static_cast<const $classname$&>(from_msg);\n");
+  }
+  format.Indent();
   format(
-      "void $classname$::MergeFrom(const $classname$& from) {\n"
       "$annotate_mergefrom$"
       "// @@protoc_insertion_point(class_specific_merge_from_start:"
-      "$full_name$)\n"
-      "  $DCHK$_NE(&from, this);\n");
-  format.Indent();
+      "$full_name$)\n");
+  format("$DCHK$_NE(&from, _this);\n");
 
   format(
       "$uint32$ cached_has_bits = 0;\n"
       "(void) cached_has_bits;\n\n");
 
+  if (ShouldSplit(descriptor_, options_)) {
+    format(
+        "if (!from.IsSplitMessageDefault()) {\n"
+        "  _this->PrepareSplitMessageForWrite();\n"
+        "}\n");
+  }
+
   std::vector<std::vector<const FieldDescriptor*>> chunks = CollectFields(
       optimized_order_,
       [&](const FieldDescriptor* a, const FieldDescriptor* b) -> bool {
-        return HasByteIndex(a) == HasByteIndex(b);
+        return HasByteIndex(a) == HasByteIndex(b) &&
+               ShouldSplit(a, options_) == ShouldSplit(b, options_);
       });
 
-  ColdChunkSkipper cold_skipper(options_, chunks, has_bit_indices_, kColdRatio);
+  ColdChunkSkipper cold_skipper(descriptor_, options_, chunks, has_bit_indices_,
+                                kColdRatio);
 
   // cached_has_word_index maintains that:
   //   cached_has_bits = from._has_bits_[cached_has_word_index]
@@ -3198,7 +3523,8 @@ void MessageGenerator::GenerateClassSpecificMergeFrom(io::Printer* printer) {
       if (deferred_has_bit_changes) {
         // Flush the has bits for the primitives we deferred.
         GOOGLE_CHECK_LE(0, cached_has_word_index);
-        format("$has_bits$[$1$] |= cached_has_bits;\n", cached_has_word_index);
+        format("_this->$has_bits$[$1$] |= cached_has_bits;\n",
+               cached_has_word_index);
       }
 
       format.Outdent();
@@ -3235,7 +3561,7 @@ void MessageGenerator::GenerateClassSpecificMergeFrom(io::Printer* printer) {
   }
   if (num_weak_fields_) {
     format(
-        "$weak_field_map$.MergeFrom(from.$weak_field_map$);"
+        "_this->$weak_field_map$.MergeFrom(from.$weak_field_map$);"
         "\n");
   }
 
@@ -3243,12 +3569,13 @@ void MessageGenerator::GenerateClassSpecificMergeFrom(io::Printer* printer) {
   // the opportunity for tail calls.
   if (descriptor_->extension_range_count() > 0) {
     format(
-        "$extensions$.MergeFrom(internal_default_instance(), "
+        "_this->$extensions$.MergeFrom(internal_default_instance(), "
         "from.$extensions$);\n");
   }
 
   format(
-      "_internal_metadata_.MergeFrom<$unknown_fields_type$>(from._internal_"
+      "_this->_internal_metadata_.MergeFrom<$unknown_fields_type$>(from._"
+      "internal_"
       "metadata_);\n");
 
   format.Outdent();
@@ -3263,12 +3590,12 @@ void MessageGenerator::GenerateCopyFrom(io::Printer* printer) {
     // takes in the Message base class as a parameter); instead we just
     // let the base Message::CopyFrom take care of it.  The base MergeFrom
     // knows how to quickly confirm the types exactly match, and if so, will
-    // use GetClassData() to get the address of Message::CopyWithSizeCheck,
+    // use GetClassData() to get the address of Message::CopyWithSourceCheck,
     // which calls Clear() and then MergeFrom(), as well as making sure that
-    // clearing the destination message doesn't alter the size of the source,
-    // when in debug builds.
-    // Most callers avoid this by passing a "from" message that is the same
-    // type as the message being merged into, rather than a generic Message.
+    // clearing the destination message doesn't alter the source, when in debug
+    // builds. Most callers avoid this by passing a "from" message that is the
+    // same type as the message being merged into, rather than a generic
+    // Message.
   }
 
   // Generate the class-specific CopyFrom.
@@ -3280,20 +3607,33 @@ void MessageGenerator::GenerateCopyFrom(io::Printer* printer) {
 
   format("if (&from == this) return;\n");
 
-  if (!options_.opensource_runtime) {
+  if (!options_.opensource_runtime && HasMessageFieldOrExtension(descriptor_)) {
     // This check is disabled in the opensource release because we're
     // concerned that many users do not define NDEBUG in their release builds.
+    // It is also disabled if a message has neither message fields nor
+    // extensions, as it's impossible to copy from its descendant.
+    //
+    // Note that FailIfCopyFromDescendant is implemented by reflection and not
+    // available for lite runtime. In that case, check if the size of the source
+    // has changed after Clear.
+    format("#ifndef NDEBUG\n");
+    if (HasDescriptorMethods(descriptor_->file(), options_)) {
+      format("FailIfCopyFromDescendant(*this, from);\n");
+    } else {
+      format("size_t from_size = from.ByteSizeLong();\n");
+    }
     format(
-        "#ifndef NDEBUG\n"
-        "size_t from_size = from.ByteSizeLong();\n"
         "#endif\n"
-        "Clear();\n"
-        "#ifndef NDEBUG\n"
-        "$CHK$_EQ(from_size, from.ByteSizeLong())\n"
-        "  << \"Source of CopyFrom changed when clearing target.  Either \"\n"
-        "     \"source is a nested message in target (not allowed), or \"\n"
-        "     \"another thread is modifying the source.\";\n"
-        "#endif\n");
+        "Clear();\n");
+    if (!HasDescriptorMethods(descriptor_->file(), options_)) {
+      format(
+          "#ifndef NDEBUG\n"
+          "$CHK$_EQ(from_size, from.ByteSizeLong())\n"
+          "  << \"Source of CopyFrom changed when clearing target.  Either \"\n"
+          "     \"source is a nested message in target (not allowed), or \"\n"
+          "     \"another thread is modifying the source.\";\n"
+          "#endif\n");
+    }
   } else {
     format("Clear();\n");
   }
@@ -3485,7 +3825,7 @@ void MessageGenerator::GenerateSerializeWithCachedSizesBody(
             // Reload.
             int new_index = has_bit_index / 32;
 
-            format_("cached_has_bits = _has_bits_[$1$];\n", new_index);
+            format_("cached_has_bits = _impl_._has_bits_[$1$];\n", new_index);
 
             cached_has_bit_index_ = new_index;
           }
@@ -3878,14 +4218,16 @@ void MessageGenerator::GenerateByteSize(io::Printer* printer) {
   std::vector<std::vector<const FieldDescriptor*>> chunks = CollectFields(
       optimized_order_,
       [&](const FieldDescriptor* a, const FieldDescriptor* b) -> bool {
-        return a->label() == b->label() && HasByteIndex(a) == HasByteIndex(b);
+        return a->label() == b->label() && HasByteIndex(a) == HasByteIndex(b) &&
+               ShouldSplit(a, options_) == ShouldSplit(b, options_);
       });
 
   // Remove chunks with required fields.
   chunks.erase(std::remove_if(chunks.begin(), chunks.end(), IsRequired),
                chunks.end());
 
-  ColdChunkSkipper cold_skipper(options_, chunks, has_bit_indices_, kColdRatio);
+  ColdChunkSkipper cold_skipper(descriptor_, options_, chunks, has_bit_indices_,
+                                kColdRatio);
   int cached_has_word_index = -1;
 
   format(
diff --git a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_message.h b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/message.h
index 5e4bbe84b83..960bea8e5af 100644
--- a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_message.h
+++ b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/message.h
@@ -40,11 +40,11 @@
 #include <set>
 #include <string>
 
-#include <google/protobuf/compiler/cpp/cpp_field.h>
-#include <google/protobuf/compiler/cpp/cpp_helpers.h>
-#include <google/protobuf/compiler/cpp/cpp_message_layout_helper.h>
-#include <google/protobuf/compiler/cpp/cpp_options.h>
-#include <google/protobuf/compiler/cpp/cpp_parse_function_generator.h>
+#include <google/protobuf/compiler/cpp/field.h>
+#include <google/protobuf/compiler/cpp/helpers.h>
+#include <google/protobuf/compiler/cpp/message_layout_helper.h>
+#include <google/protobuf/compiler/cpp/options.h>
+#include <google/protobuf/compiler/cpp/parse_function_generator.h>
 
 namespace google {
 namespace protobuf {
@@ -119,6 +119,9 @@ class MessageGenerator {
   // default instance.
   void GenerateConstexprConstructor(io::Printer* printer);
 
+  void GenerateCreateSplitMessage(io::Printer* printer);
+  void GenerateInitDefaultSplitInstance(io::Printer* printer);
+
   // Generate standard Message methods.
   void GenerateClear(io::Printer* printer);
   void GenerateOneofClear(io::Printer* printer);
@@ -129,7 +132,7 @@ class MessageGenerator {
   void GenerateSerializeWithCachedSizesBodyShuffled(io::Printer* printer);
   void GenerateByteSize(io::Printer* printer);
   void GenerateMergeFrom(io::Printer* printer);
-  void GenerateClassSpecificMergeFrom(io::Printer* printer);
+  void GenerateClassSpecificMergeImpl(io::Printer* printer);
   void GenerateCopyFrom(io::Printer* printer);
   void GenerateSwap(io::Printer* printer);
   void GenerateIsInitialized(io::Printer* printer);
@@ -161,9 +164,8 @@ class MessageGenerator {
   void GenerateFieldClear(const FieldDescriptor* field, bool is_inline,
                           Formatter format);
 
-  void GenerateConstructorBody(io::Printer* printer,
-                               std::vector<bool> already_processed,
-                               bool copy_constructor) const;
+  // Generates the body of the message's copy constructor.
+  void GenerateCopyConstructorBody(io::Printer* printer) const;
 
   // Returns the level that this message needs ArenaDtor. If the message has
   // a field that is not arena-exclusive, it needs an ArenaDtor
diff --git a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_message_field.cc b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/message_field.cc
index 3b9f09c8c8b..9a91fd91720 100644
--- a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_message_field.cc
+++ b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/message_field.cc
@@ -32,10 +32,11 @@
 //  Based on original Protocol Buffers design by
 //  Sanjay Ghemawat, Jeff Dean, and others.
 
-#include <google/protobuf/compiler/cpp/cpp_message_field.h>
+#include <google/protobuf/compiler/cpp/message_field.h>
 
 #include <google/protobuf/io/printer.h>
-#include <google/protobuf/compiler/cpp/cpp_helpers.h>
+#include <google/protobuf/compiler/cpp/field.h>
+#include <google/protobuf/compiler/cpp/helpers.h>
 
 #include <google/protobuf/stubs/strutil.h>
 
@@ -157,8 +158,7 @@ void MessageFieldGenerator::GenerateAccessorDeclarations(
 }
 
 void MessageFieldGenerator::GenerateNonInlineAccessorDefinitions(
-    io::Printer* printer) const {
-}
+    io::Printer* printer) const {}
 
 void MessageFieldGenerator::GenerateInlineAccessorDefinitions(
     io::Printer* printer) const {
@@ -179,6 +179,7 @@ void MessageFieldGenerator::GenerateInlineAccessorDefinitions(
   format(
       "inline void $classname$::unsafe_arena_set_allocated_$name$(\n"
       "    $type$* $name$) {\n"
+      "$maybe_prepare_split_message$"
       // If we're not on an arena, free whatever we were holding before.
       // (If we are on arena, we can just forget the earlier pointer.)
       "  if (GetArenaForAllocation() == nullptr) {\n"
@@ -204,6 +205,7 @@ void MessageFieldGenerator::GenerateInlineAccessorDefinitions(
       "inline $type$* $classname$::$release_name$() {\n"
       "$type_reference_function$"
       "$annotate_release$"
+      "$maybe_prepare_split_message$"
       "  $clear_hasbit$\n"
       "  $type$* temp = $casted_member$;\n"
       "  $field$ = nullptr;\n"
@@ -222,6 +224,7 @@ void MessageFieldGenerator::GenerateInlineAccessorDefinitions(
       "$annotate_release$"
       "  // @@protoc_insertion_point(field_release:$full_name$)\n"
       "$type_reference_function$"
+      "$maybe_prepare_split_message$"
       "  $clear_hasbit$\n"
       "  $type$* temp = $casted_member$;\n"
       "  $field$ = nullptr;\n"
@@ -244,6 +247,9 @@ void MessageFieldGenerator::GenerateInlineAccessorDefinitions(
       "  return $casted_member$;\n"
       "}\n"
       "inline $type$* $classname$::mutable_$name$() {\n"
+      // TODO(b/122856539): add tests to make sure all write accessors are able
+      // to prepare split message allocation.
+      "$maybe_prepare_split_message$"
       "  $type$* _msg = _internal_mutable_$name$();\n"
       "$annotate_mutable$"
       "  // @@protoc_insertion_point(field_mutable:$full_name$)\n"
@@ -255,7 +261,9 @@ void MessageFieldGenerator::GenerateInlineAccessorDefinitions(
   format(
       "inline void $classname$::set_allocated_$name$($type$* $name$) {\n"
       "  ::$proto_ns$::Arena* message_arena = GetArenaForAllocation();\n");
-  format("  if (message_arena == nullptr) {\n");
+  format(
+      "$maybe_prepare_split_message$"
+      "  if (message_arena == nullptr) {\n");
   if (IsCrossFileMessage(descriptor_)) {
     format(
         "    delete reinterpret_cast< ::$proto_ns$::MessageLite*>($field$);\n");
@@ -407,12 +415,12 @@ void MessageFieldGenerator::GenerateMergingCode(io::Printer* printer) const {
   Formatter format(printer, variables_);
   if (implicit_weak_field_) {
     format(
-        "_Internal::mutable_$name$(this)->CheckTypeAndMergeFrom(\n"
+        "_Internal::mutable_$name$(_this)->CheckTypeAndMergeFrom(\n"
         "    _Internal::$name$(&from));\n");
   } else {
     format(
-        "_internal_mutable_$name$()->$type$::MergeFrom(from._internal_$name$())"
-        ";\n");
+        "_this->_internal_mutable_$name$()->$type$::MergeFrom(\n"
+        "    from._internal_$name$());\n");
   }
 }
 
@@ -435,17 +443,13 @@ void MessageFieldGenerator::GenerateDestructorCode(io::Printer* printer) const {
     // care when handling them.
     format("if (this != internal_default_instance()) ");
   }
+  if (ShouldSplit(descriptor_, options_)) {
+    format("delete $cached_split_ptr$->$name$_;\n");
+    return;
+  }
   format("delete $field$;\n");
 }
 
-void MessageFieldGenerator::GenerateConstructorCode(
-    io::Printer* printer) const {
-  GOOGLE_CHECK(!IsFieldStripped(descriptor_, options_));
-
-  Formatter format(printer, variables_);
-  format("$field$ = nullptr;\n");
-}
-
 void MessageFieldGenerator::GenerateCopyConstructorCode(
     io::Printer* printer) const {
   GOOGLE_CHECK(!IsFieldStripped(descriptor_, options_));
@@ -453,9 +457,7 @@ void MessageFieldGenerator::GenerateCopyConstructorCode(
   Formatter format(printer, variables_);
   format(
       "if (from._internal_has_$name$()) {\n"
-      "  $field$ = new $type$(*from.$field$);\n"
-      "} else {\n"
-      "  $field$ = nullptr;\n"
+      "  _this->$field$ = new $type$(*from.$field$);\n"
       "}\n");
 }
 
@@ -500,10 +502,26 @@ void MessageFieldGenerator::GenerateIsInitialized(io::Printer* printer) const {
       "}\n");
 }
 
-void MessageFieldGenerator::GenerateConstinitInitializer(
+void MessageFieldGenerator::GenerateConstexprAggregateInitializer(
     io::Printer* printer) const {
   Formatter format(printer, variables_);
-  format("$name$_(nullptr)");
+  format("/*decltype($field$)*/nullptr");
+}
+
+void MessageFieldGenerator::GenerateCopyAggregateInitializer(
+    io::Printer* printer) const {
+  Formatter format(printer, variables_);
+  format("decltype($field$){nullptr}");
+}
+
+void MessageFieldGenerator::GenerateAggregateInitializer(
+    io::Printer* printer) const {
+  Formatter format(printer, variables_);
+  if (ShouldSplit(descriptor_, options_)) {
+    format("decltype(Impl_::Split::$name$_){nullptr}");
+    return;
+  }
+  format("decltype($field$){nullptr}");
 }
 
 // ===================================================================
@@ -830,7 +848,7 @@ void RepeatedMessageFieldGenerator::GenerateMergingCode(
   GOOGLE_CHECK(!IsFieldStripped(descriptor_, options_));
 
   Formatter format(printer, variables_);
-  format("$field$.MergeFrom(from.$field$);\n");
+  format("_this->$field$.MergeFrom(from.$field$);\n");
 }
 
 void RepeatedMessageFieldGenerator::GenerateSwappingCode(
@@ -846,6 +864,18 @@ void RepeatedMessageFieldGenerator::GenerateConstructorCode(
   // Not needed for repeated fields.
 }
 
+void RepeatedMessageFieldGenerator::GenerateDestructorCode(
+    io::Printer* printer) const {
+  GOOGLE_CHECK(!IsFieldStripped(descriptor_, options_));
+
+  Formatter format(printer, variables_);
+  if (implicit_weak_field_) {
+    format("$field$.~WeakRepeatedPtrField();\n");
+  } else {
+    format("$field$.~RepeatedPtrField();\n");
+  }
+}
+
 void RepeatedMessageFieldGenerator::GenerateSerializeWithCachedSizesToArray(
     io::Printer* printer) const {
   GOOGLE_CHECK(!IsFieldStripped(descriptor_, options_));
@@ -922,12 +952,6 @@ void RepeatedMessageFieldGenerator::GenerateIsInitialized(
   }
 }
 
-void RepeatedMessageFieldGenerator::GenerateConstinitInitializer(
-    io::Printer* printer) const {
-  Formatter format(printer, variables_);
-  format("$name$_()");
-}
-
 }  // namespace cpp
 }  // namespace compiler
 }  // namespace protobuf
diff --git a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_message_field.h b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/message_field.h
index 528b4197048..70c42c0eacc 100644
--- a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_message_field.h
+++ b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/message_field.h
@@ -38,8 +38,8 @@
 #include <map>
 #include <string>
 
-#include <google/protobuf/compiler/cpp/cpp_field.h>
-#include <google/protobuf/compiler/cpp/cpp_helpers.h>
+#include <google/protobuf/compiler/cpp/field.h>
+#include <google/protobuf/compiler/cpp/helpers.h>
 
 namespace google {
 namespace protobuf {
@@ -67,13 +67,16 @@ class MessageFieldGenerator : public FieldGenerator {
   void GenerateMergingCode(io::Printer* printer) const override;
   void GenerateSwappingCode(io::Printer* printer) const override;
   void GenerateDestructorCode(io::Printer* printer) const override;
-  void GenerateConstructorCode(io::Printer* printer) const override;
+  void GenerateConstructorCode(io::Printer* printer) const override {}
   void GenerateCopyConstructorCode(io::Printer* printer) const override;
   void GenerateSerializeWithCachedSizesToArray(
       io::Printer* printer) const override;
   void GenerateByteSize(io::Printer* printer) const override;
   void GenerateIsInitialized(io::Printer* printer) const override;
-  void GenerateConstinitInitializer(io::Printer* printer) const override;
+  void GenerateConstexprAggregateInitializer(
+      io::Printer* printer) const override;
+  void GenerateAggregateInitializer(io::Printer* printer) const override;
+  void GenerateCopyAggregateInitializer(io::Printer* printer) const override;
 
  protected:
   const bool implicit_weak_field_;
@@ -124,11 +127,11 @@ class RepeatedMessageFieldGenerator : public FieldGenerator {
   void GenerateSwappingCode(io::Printer* printer) const override;
   void GenerateConstructorCode(io::Printer* printer) const override;
   void GenerateCopyConstructorCode(io::Printer* printer) const override {}
+  void GenerateDestructorCode(io::Printer* printer) const override;
   void GenerateSerializeWithCachedSizesToArray(
       io::Printer* printer) const override;
   void GenerateByteSize(io::Printer* printer) const override;
   void GenerateIsInitialized(io::Printer* printer) const override;
-  void GenerateConstinitInitializer(io::Printer* printer) const override;
 
  private:
   const bool implicit_weak_field_;
diff --git a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_message_layout_helper.h b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/message_layout_helper.h
index 80860053f17..a8813a1f225 100644
--- a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_message_layout_helper.h
+++ b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/message_layout_helper.h
@@ -36,7 +36,7 @@
 #define GOOGLE_PROTOBUF_COMPILER_CPP_MESSAGE_LAYOUT_HELPER_H__
 
 #include <google/protobuf/descriptor.h>
-#include <google/protobuf/compiler/cpp/cpp_options.h>
+#include <google/protobuf/compiler/cpp/options.h>
 
 namespace google {
 namespace protobuf {
diff --git a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_names.h b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/names.h
index 39563cd0cdf..8220f7dde8c 100644
--- a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_names.h
+++ b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/names.h
@@ -51,9 +51,9 @@ namespace cpp {
 //
 // For example, if you had:
 //   package foo.bar;
-//   message Baz { message Qux {} }
+//   message Baz { message Moo {} }
 // Then the non-qualified version would be:
-//   Baz_Qux
+//   Baz_Moo
 TProtoStringType ClassName(const Descriptor* descriptor);
 TProtoStringType ClassName(const EnumDescriptor* enum_descriptor);
 
@@ -61,9 +61,9 @@ TProtoStringType ClassName(const EnumDescriptor* enum_descriptor);
 //
 // For example, if you had:
 //   package foo.bar;
-//   message Baz { message Qux {} }
-// Then the qualified ClassName for Qux would be:
-//   ::foo::bar::Baz_Qux
+//   message Baz { message Moo {} }
+// Then the qualified ClassName for Moo would be:
+//   ::foo::bar::Baz_Moo
 TProtoStringType QualifiedClassName(const Descriptor* d);
 TProtoStringType QualifiedClassName(const EnumDescriptor* d);
 TProtoStringType QualifiedExtensionName(const FieldDescriptor* d);
diff --git a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_options.h b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/options.h
index 48512a64c87..14546ca6187 100644
--- a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_options.h
+++ b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/options.h
@@ -80,9 +80,10 @@ struct Options {
   bool opensource_runtime = false;
   bool annotate_accessor = false;
   bool unused_field_stripping = false;
-  bool unverified_lazy_message_sets = true;
-  bool eagerly_verified_lazy = true;
+  bool unverified_lazy_message_sets = false;
+  bool unverified_lazy = false;
   bool profile_driven_inline_string = true;
+  bool message_owned_arena_trial = false;
   bool force_split = false;
 #ifdef PROTOBUF_STABLE_EXPERIMENTS
   bool force_eagerly_verified_lazy = true;
diff --git a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_padding_optimizer.cc b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/padding_optimizer.cc
index f48ba718a54..20910520d63 100644
--- a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_padding_optimizer.cc
+++ b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/padding_optimizer.cc
@@ -28,9 +28,9 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-#include <google/protobuf/compiler/cpp/cpp_padding_optimizer.h>
+#include <google/protobuf/compiler/cpp/padding_optimizer.h>
 
-#include <google/protobuf/compiler/cpp/cpp_helpers.h>
+#include <google/protobuf/compiler/cpp/helpers.h>
 
 namespace google {
 namespace protobuf {
diff --git a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_padding_optimizer.h b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/padding_optimizer.h
index ebdb17de61f..9c76f38c471 100644
--- a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_padding_optimizer.h
+++ b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/padding_optimizer.h
@@ -35,7 +35,7 @@
 #ifndef GOOGLE_PROTOBUF_COMPILER_CPP_PADDING_OPTIMIZER_H__
 #define GOOGLE_PROTOBUF_COMPILER_CPP_PADDING_OPTIMIZER_H__
 
-#include <google/protobuf/compiler/cpp/cpp_message_layout_helper.h>
+#include <google/protobuf/compiler/cpp/message_layout_helper.h>
 
 namespace google {
 namespace protobuf {
diff --git a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_parse_function_generator.cc b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/parse_function_generator.cc
index e033856f0c7..1b97182acd6 100644
--- a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_parse_function_generator.cc
+++ b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/parse_function_generator.cc
@@ -28,7 +28,7 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-#include <google/protobuf/compiler/cpp/cpp_parse_function_generator.h>
+#include <google/protobuf/compiler/cpp/parse_function_generator.h>
 
 #include <algorithm>
 #include <limits>
@@ -36,7 +36,7 @@
 #include <utility>
 
 #include <google/protobuf/wire_format.h>
-#include <google/protobuf/compiler/cpp/cpp_helpers.h>
+#include <google/protobuf/compiler/cpp/helpers.h>
 
 namespace google {
 namespace protobuf {
@@ -231,8 +231,7 @@ std::vector<const FieldDescriptor*> FilterMiniParsedFields(
         break;
 
       case FieldDescriptor::TYPE_ENUM:
-        if (field->is_repeated() &&
-            !HasPreservingUnknownEnumSemantics(field)) {
+        if (field->is_repeated() && !HasPreservingUnknownEnumSemantics(field)) {
           // TODO(b/206890171): handle packed repeated closed enums
           // Non-packed repeated can be handled using tables, but we still
           // need to generate fallback code for all repeated enums in order to
@@ -244,15 +243,15 @@ std::vector<const FieldDescriptor*> FilterMiniParsedFields(
         }
         break;
 
-        case FieldDescriptor::TYPE_BYTES:
-        case FieldDescriptor::TYPE_STRING:
-          if (IsStringInlined(field, options)) {
-            // TODO(b/198211897): support InilnedStringField.
-            handled = false;
-          } else {
-            handled = true;
-          }
-          break;
+      case FieldDescriptor::TYPE_BYTES:
+      case FieldDescriptor::TYPE_STRING:
+        if (IsStringInlined(field, options)) {
+          // TODO(b/198211897): support InilnedStringField.
+          handled = false;
+        } else {
+          handled = true;
+        }
+        break;
 
       case FieldDescriptor::TYPE_MESSAGE:
       case FieldDescriptor::TYPE_GROUP:
@@ -291,8 +290,9 @@ TailCallTableInfo::TailCallTableInfo(
     GOOGLE_LOG_IF(DFATAL, ordered_fields.empty())
         << "Invalid message: " << descriptor->full_name() << " has "
         << oneof_count << " oneof declarations, but no fields";
-    aux_entries.push_back(StrCat(
-        "_fl::Offset{offsetof(", ClassName(descriptor), ", _oneof_case_)}"));
+    aux_entries.push_back(StrCat("_fl::Offset{offsetof(",
+                                       ClassName(descriptor),
+                                       ", _impl_._oneof_case_)}"));
   }
 
   // If this message has any inlined string fields, store the donation state
@@ -301,7 +301,7 @@ TailCallTableInfo::TailCallTableInfo(
     aux_entries.resize(2);  // pad if necessary
     aux_entries[1] =
         StrCat("_fl::Offset{offsetof(", ClassName(descriptor),
-                     ", _inlined_string_donated_)}");
+                     ", _impl_._inlined_string_donated_)}");
   }
 
   // Fill in mini table entries.
@@ -444,7 +444,7 @@ ParseFunctionGenerator::ParseFunctionGenerator(
         inlined_string_indices, scc_analyzer));
   }
   SetCommonVars(options_, &variables_);
-  SetCommonMessageDataVariables(&variables_);
+  SetCommonMessageDataVariables(descriptor_, &variables_);
   SetUnknownFieldsVariable(descriptor_, options_, &variables_);
   variables_["classname"] = ClassName(descriptor, false);
 }
@@ -547,13 +547,13 @@ void ParseFunctionGenerator::GenerateTailcallFallbackFunction(
 
   if (num_hasbits_ > 0) {
     // Sync hasbits
-    format("typed_msg->_has_bits_[0] = hasbits;\n");
+    format("typed_msg->_impl_._has_bits_[0] = hasbits;\n");
   }
   format("arc_ui32 tag = data.tag();\n");
 
   format.Set("msg", "typed_msg->");
   format.Set("this", "typed_msg");
-  format.Set("has_bits", "typed_msg->_has_bits_");
+  format.Set("has_bits", "typed_msg->_impl_._has_bits_");
   format.Set("next_tag", "goto next_tag");
   GenerateParseIterationBody(format, descriptor_,
                              tc_table_info_->fallback_fields);
@@ -649,7 +649,7 @@ void ParseFunctionGenerator::GenerateLoopingParseFunction(Formatter& format) {
     format("_Internal::HasBits has_bits{};\n");
     format.Set("has_bits", "has_bits");
   } else {
-    format.Set("has_bits", "_has_bits_");
+    format.Set("has_bits", "_impl_._has_bits_");
   }
   format.Set("next_tag", "continue");
   format("while (!ctx->Done(&ptr)) {\n");
@@ -665,7 +665,7 @@ void ParseFunctionGenerator::GenerateLoopingParseFunction(Formatter& format) {
 
   format.Outdent();
   format("message_done:\n");
-  if (hasbits_size) format("  _has_bits_.Or(has_bits);\n");
+  if (hasbits_size) format("  _impl_._has_bits_.Or(has_bits);\n");
 
   format(
       "  return ptr;\n"
@@ -774,7 +774,7 @@ void ParseFunctionGenerator::GenerateTailCallTable(Formatter& format) {
     {
       auto header_scope = format.ScopedIndent();
       if (num_hasbits_ > 0 || IsMapEntryMessage(descriptor_)) {
-        format("PROTOBUF_FIELD_OFFSET($classname$, _has_bits_),\n");
+        format("PROTOBUF_FIELD_OFFSET($classname$, _impl_._has_bits_),\n");
       } else {
         format("0,  // no _has_bits_\n");
       }
@@ -899,11 +899,14 @@ void ParseFunctionGenerator::GenerateFastFieldEntries(Formatter& format) {
     if (info.func_name.empty()) {
       format("{::_pbi::TcParser::MiniParse, {}},\n");
     } else {
+      bool cold = ShouldSplit(info.field, options_);
       format(
           "{$1$,\n"
-          " {$2$, $3$, $4$, PROTOBUF_FIELD_OFFSET($classname$, $5$)}},\n",
+          " {$2$, $3$, $4$, PROTOBUF_FIELD_OFFSET($classname$$5$, $6$)}},\n",
           info.func_name, info.coded_tag, info.hasbit_idx, info.aux_idx,
-          FieldMemberName(info.field));
+          cold ? "::Impl_::Split" : "",
+          cold ? FieldName(info.field) + "_"
+               : FieldMemberName(info.field, /*cold=*/false));
     }
   }
 }
@@ -1048,8 +1051,11 @@ void ParseFunctionGenerator::GenerateFieldEntries(Formatter& format) {
       format("/* weak */ 0, 0, 0, 0");
     } else {
       const OneofDescriptor* oneof = field->real_containing_oneof();
-      format("PROTOBUF_FIELD_OFFSET($classname$, $1$), $2$, $3$,\n ",
-             FieldMemberName(field),
+      bool cold = ShouldSplit(field, options_);
+      format("PROTOBUF_FIELD_OFFSET($classname$$1$, $2$), $3$, $4$,\n ",
+             cold ? "::Impl_::Split" : "",
+             cold ? FieldName(field) + "_"
+                  : FieldMemberName(field, /*cold=*/false),
              (oneof ? oneof->index() : entry.hasbit_idx), entry.aux_idx);
       FormatFieldKind(format, entry, options_, scc_analyzer_);
     }
@@ -1550,7 +1556,8 @@ void ParseFunctionGenerator::GenerateFieldSwitch(
   format.Indent();
 
   for (const auto* field : fields) {
-    format.Set("field", FieldMemberName(field));
+    bool cold = ShouldSplit(field, options_);
+    format.Set("field", FieldMemberName(field, cold));
     PrintFieldComment(format, field);
     format("case $1$:\n", field->number());
     format.Indent();
@@ -1559,6 +1566,9 @@ void ParseFunctionGenerator::GenerateFieldSwitch(
     format("if (PROTOBUF_PREDICT_TRUE(static_cast<$uint8$>(tag) == $1$)) {\n",
            expected_tag & 0xFF);
     format.Indent();
+    if (cold) {
+      format("$msg$PrepareSplitMessageForWrite();\n");
+    }
     auto wiretype = WireFormatLite::GetTagWireType(expected_tag);
     arc_ui32 tag = WireFormatLite::MakeTag(field->number(), wiretype);
     int tag_size = io::CodedOutputStream::VarintSize32(tag);
diff --git a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_parse_function_generator.h b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/parse_function_generator.h
index 3c8209534a4..7e2b674852f 100644
--- a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_parse_function_generator.h
+++ b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/parse_function_generator.h
@@ -38,8 +38,8 @@
 #include <google/protobuf/io/printer.h>
 #include <google/protobuf/descriptor.h>
 #include <google/protobuf/wire_format_lite.h>
-#include <google/protobuf/compiler/cpp/cpp_helpers.h>
-#include <google/protobuf/compiler/cpp/cpp_options.h>
+#include <google/protobuf/compiler/cpp/helpers.h>
+#include <google/protobuf/compiler/cpp/options.h>
 
 namespace google {
 namespace protobuf {
diff --git a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_primitive_field.cc b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/primitive_field.cc
index 910b59a21a7..9dbf16ae7eb 100644
--- a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_primitive_field.cc
+++ b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/primitive_field.cc
@@ -32,12 +32,12 @@
 //  Based on original Protocol Buffers design by
 //  Sanjay Ghemawat, Jeff Dean, and others.
 
-#include <google/protobuf/compiler/cpp/cpp_primitive_field.h>
+#include <google/protobuf/compiler/cpp/primitive_field.h>
 
 #include <google/protobuf/io/printer.h>
 #include <google/protobuf/wire_format.h>
 #include <google/protobuf/stubs/strutil.h>
-#include <google/protobuf/compiler/cpp/cpp_helpers.h>
+#include <google/protobuf/compiler/cpp/helpers.h>
 
 namespace google {
 namespace protobuf {
@@ -105,8 +105,9 @@ void SetPrimitiveVariables(const FieldDescriptor* descriptor,
   (*variables)["type"] = PrimitiveTypeName(options, descriptor->cpp_type());
   (*variables)["default"] = DefaultValue(options, descriptor);
   (*variables)["cached_byte_size_name"] = MakeVarintCachedSizeName(descriptor);
+  bool cold = ShouldSplit(descriptor, options);
   (*variables)["cached_byte_size_field"] =
-      MakeVarintCachedSizeFieldName(descriptor);
+      MakeVarintCachedSizeFieldName(descriptor, cold);
   (*variables)["tag"] = StrCat(internal::WireFormat::MakeTag(descriptor));
   int fixed_size = FixedSize(descriptor->type());
   if (fixed_size != -1) {
@@ -165,6 +166,7 @@ void PrimitiveFieldGenerator::GenerateInlineAccessorDefinitions(
       "  $field$ = value;\n"
       "}\n"
       "inline void $classname$::set_$name$($type$ value) {\n"
+      "$maybe_prepare_split_message$"
       "  _internal_set_$name$(value);\n"
       "$annotate_set$"
       "  // @@protoc_insertion_point(field_set:$full_name$)\n"
@@ -178,7 +180,7 @@ void PrimitiveFieldGenerator::GenerateClearingCode(io::Printer* printer) const {
 
 void PrimitiveFieldGenerator::GenerateMergingCode(io::Printer* printer) const {
   Formatter format(printer, variables_);
-  format("_internal_set_$name$(from._internal_$name$());\n");
+  format("_this->_internal_set_$name$(from._internal_$name$());\n");
 }
 
 void PrimitiveFieldGenerator::GenerateSwappingCode(io::Printer* printer) const {
@@ -186,16 +188,10 @@ void PrimitiveFieldGenerator::GenerateSwappingCode(io::Printer* printer) const {
   format("swap($field$, other->$field$);\n");
 }
 
-void PrimitiveFieldGenerator::GenerateConstructorCode(
-    io::Printer* printer) const {
-  Formatter format(printer, variables_);
-  format("$field$ = $default$;\n");
-}
-
 void PrimitiveFieldGenerator::GenerateCopyConstructorCode(
     io::Printer* printer) const {
   Formatter format(printer, variables_);
-  format("$field$ = from.$field$;\n");
+  format("_this->$field$ = from.$field$;\n");
 }
 
 void PrimitiveFieldGenerator::GenerateSerializeWithCachedSizesToArray(
@@ -230,10 +226,26 @@ void PrimitiveFieldGenerator::GenerateByteSize(io::Printer* printer) const {
   }
 }
 
-void PrimitiveFieldGenerator::GenerateConstinitInitializer(
+void PrimitiveFieldGenerator::GenerateConstexprAggregateInitializer(
     io::Printer* printer) const {
   Formatter format(printer, variables_);
-  format("$name$_($default$)");
+  format("/*decltype($field$)*/$default$");
+}
+
+void PrimitiveFieldGenerator::GenerateAggregateInitializer(
+    io::Printer* printer) const {
+  Formatter format(printer, variables_);
+  if (ShouldSplit(descriptor_, options_)) {
+    format("decltype(Impl_::Split::$name$_){$default$}");
+    return;
+  }
+  format("decltype($field$){$default$}");
+}
+
+void PrimitiveFieldGenerator::GenerateCopyAggregateInitializer(
+    io::Printer* printer) const {
+  Formatter format(printer, variables_);
+  format("decltype($field$){}");
 }
 
 // ===================================================================
@@ -398,7 +410,7 @@ void RepeatedPrimitiveFieldGenerator::GenerateClearingCode(
 void RepeatedPrimitiveFieldGenerator::GenerateMergingCode(
     io::Printer* printer) const {
   Formatter format(printer, variables_);
-  format("$field$.MergeFrom(from.$field$);\n");
+  format("_this->$field$.MergeFrom(from.$field$);\n");
 }
 
 void RepeatedPrimitiveFieldGenerator::GenerateSwappingCode(
@@ -407,6 +419,12 @@ void RepeatedPrimitiveFieldGenerator::GenerateSwappingCode(
   format("$field$.InternalSwap(&other->$field$);\n");
 }
 
+void RepeatedPrimitiveFieldGenerator::GenerateDestructorCode(
+    io::Printer* printer) const {
+  Formatter format(printer, variables_);
+  format("$field$.~RepeatedField();\n");
+}
+
 void RepeatedPrimitiveFieldGenerator::GenerateSerializeWithCachedSizesToArray(
     io::Printer* printer) const {
   Formatter format(printer, variables_);
@@ -460,7 +478,8 @@ void RepeatedPrimitiveFieldGenerator::GenerateByteSize(
     format(
         "if (data_size > 0) {\n"
         "  total_size += $tag_size$ +\n"
-        "    ::_pbi::WireFormatLite::Int32Size(static_cast<$int32$>(data_size));\n"
+        "    "
+        "::_pbi::WireFormatLite::Int32Size(static_cast<$int32$>(data_size));\n"
         "}\n");
     if (FixedSize(descriptor_->type()) == -1) {
       format(
@@ -480,13 +499,37 @@ void RepeatedPrimitiveFieldGenerator::GenerateByteSize(
   format("}\n");
 }
 
-void RepeatedPrimitiveFieldGenerator::GenerateConstinitInitializer(
+void RepeatedPrimitiveFieldGenerator::GenerateConstexprAggregateInitializer(
+    io::Printer* printer) const {
+  Formatter format(printer, variables_);
+  format("/*decltype($field$)*/{}");
+  if (descriptor_->is_packed() && FixedSize(descriptor_->type()) == -1 &&
+      HasGeneratedMethods(descriptor_->file(), options_)) {
+    format("\n, /*decltype($cached_byte_size_field$)*/{0}");
+  }
+}
+
+void RepeatedPrimitiveFieldGenerator::GenerateAggregateInitializer(
     io::Printer* printer) const {
   Formatter format(printer, variables_);
-  format("$name$_()");
+  format("decltype($field$){arena}");
+  if (descriptor_->is_packed() && FixedSize(descriptor_->type()) == -1 &&
+      HasGeneratedMethods(descriptor_->file(), options_)) {
+    // std::atomic has no move constructor, which prevents explicit aggregate
+    // initialization pre-C++17.
+    format("\n, /*decltype($cached_byte_size_field$)*/{0}");
+  }
+}
+
+void RepeatedPrimitiveFieldGenerator::GenerateCopyAggregateInitializer(
+    io::Printer* printer) const {
+
+  Formatter format(printer, variables_);
+  format("decltype($field$){from.$field$}");
   if (descriptor_->is_packed() && FixedSize(descriptor_->type()) == -1 &&
       HasGeneratedMethods(descriptor_->file(), options_)) {
-    format("\n, $cached_byte_size_name$(0)");
+    // std::atomic has no move constructor.
+    format("\n, /*decltype($cached_byte_size_field$)*/{0}");
   }
 }
 
diff --git a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_primitive_field.h b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/primitive_field.h
index 77ac598e905..bb8a08aa141 100644
--- a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_primitive_field.h
+++ b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/primitive_field.h
@@ -38,7 +38,7 @@
 #include <map>
 #include <string>
 
-#include <google/protobuf/compiler/cpp/cpp_field.h>
+#include <google/protobuf/compiler/cpp/field.h>
 
 namespace google {
 namespace protobuf {
@@ -58,12 +58,15 @@ class PrimitiveFieldGenerator : public FieldGenerator {
   void GenerateClearingCode(io::Printer* printer) const override;
   void GenerateMergingCode(io::Printer* printer) const override;
   void GenerateSwappingCode(io::Printer* printer) const override;
-  void GenerateConstructorCode(io::Printer* printer) const override;
+  void GenerateConstructorCode(io::Printer* printer) const override {}
   void GenerateCopyConstructorCode(io::Printer* printer) const override;
   void GenerateSerializeWithCachedSizesToArray(
       io::Printer* printer) const override;
   void GenerateByteSize(io::Printer* printer) const override;
-  void GenerateConstinitInitializer(io::Printer* printer) const override;
+  void GenerateConstexprAggregateInitializer(
+      io::Printer* printer) const override;
+  void GenerateAggregateInitializer(io::Printer* printer) const override;
+  void GenerateCopyAggregateInitializer(io::Printer* printer) const override;
 
  private:
   GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(PrimitiveFieldGenerator);
@@ -99,11 +102,17 @@ class RepeatedPrimitiveFieldGenerator : public FieldGenerator {
   void GenerateMergingCode(io::Printer* printer) const override;
   void GenerateSwappingCode(io::Printer* printer) const override;
   void GenerateConstructorCode(io::Printer* printer) const override {}
-  void GenerateCopyConstructorCode(io::Printer* printer) const override {}
+  void GenerateCopyConstructorCode(io::Printer*  /*printer*/) const override {
+    GOOGLE_CHECK(!ShouldSplit(descriptor_, options_));
+  }
+  void GenerateDestructorCode(io::Printer* printer) const override;
   void GenerateSerializeWithCachedSizesToArray(
       io::Printer* printer) const override;
   void GenerateByteSize(io::Printer* printer) const override;
-  void GenerateConstinitInitializer(io::Printer* printer) const override;
+  void GenerateConstexprAggregateInitializer(
+      io::Printer* printer) const override;
+  void GenerateAggregateInitializer(io::Printer* printer) const override;
+  void GenerateCopyAggregateInitializer(io::Printer* printer) const override;
 
  private:
   GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(RepeatedPrimitiveFieldGenerator);
diff --git a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_service.cc b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/service.cc
index 7bf589fa388..fae7128a097 100644
--- a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_service.cc
+++ b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/service.cc
@@ -32,11 +32,11 @@
 //  Based on original Protocol Buffers design by
 //  Sanjay Ghemawat, Jeff Dean, and others.
 
-#include <google/protobuf/compiler/cpp/cpp_service.h>
+#include <google/protobuf/compiler/cpp/service.h>
 
 #include <google/protobuf/io/printer.h>
 #include <google/protobuf/stubs/strutil.h>
-#include <google/protobuf/compiler/cpp/cpp_helpers.h>
+#include <google/protobuf/compiler/cpp/helpers.h>
 
 namespace google {
 namespace protobuf {
diff --git a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_service.h b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/service.h
index d237f9d732e..56982cf566b 100644
--- a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_service.h
+++ b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/service.h
@@ -39,7 +39,7 @@
 #include <string>
 
 #include <google/protobuf/descriptor.h>
-#include <google/protobuf/compiler/cpp/cpp_options.h>
+#include <google/protobuf/compiler/cpp/options.h>
 
 namespace google {
 namespace protobuf {
diff --git a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_string_field.cc b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/string_field.cc
index 4d8744976ba..5f30d3b511e 100644
--- a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_string_field.cc
+++ b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/string_field.cc
@@ -32,11 +32,11 @@
 //  Based on original Protocol Buffers design by
 //  Sanjay Ghemawat, Jeff Dean, and others.
 
-#include <google/protobuf/compiler/cpp/cpp_string_field.h>
+#include <google/protobuf/compiler/cpp/string_field.h>
 
 #include <google/protobuf/io/printer.h>
 #include <google/protobuf/stubs/strutil.h>
-#include <google/protobuf/compiler/cpp/cpp_helpers.h>
+#include <google/protobuf/compiler/cpp/helpers.h>
 #include <google/protobuf/descriptor.pb.h>
 
 
@@ -115,11 +115,7 @@ void StringFieldGenerator::GeneratePrivateMembers(io::Printer* printer) const {
     // allocating arena is null. This is required to support message-owned
     // arena (go/path-to-arenas) where a root proto is destroyed but
     // InlinedStringField may have arena-allocated memory.
-    //
-    // `_init_inline_xxx` is used for initializing default instances.
-    format(
-        "union { ::$proto_ns$::internal::InlinedStringField $name$_; };\n"
-        "static std::true_type _init_inline_$name$_;\n");
+    format("::$proto_ns$::internal::InlinedStringField $name$_;\n");
   }
 }
 
@@ -130,6 +126,10 @@ void StringFieldGenerator::GenerateStaticMembers(io::Printer* printer) const {
         "static const ::$proto_ns$::internal::LazyString"
         " $default_variable_name$;\n");
   }
+  if (inlined_) {
+    // `_init_inline_xxx` is used for initializing default instances.
+    format("static std::true_type _init_inline_$name$_;\n");
+  }
 }
 
 void StringFieldGenerator::GenerateAccessorDeclarations(
@@ -215,6 +215,7 @@ void StringFieldGenerator::GenerateInlineAccessorDefinitions(
         "template <typename ArgT0, typename... ArgT>\n"
         "inline PROTOBUF_ALWAYS_INLINE\n"
         "void $classname$::set_$name$(ArgT0&& arg0, ArgT... args) {\n"
+        "$maybe_prepare_split_message$"
         " $set_hasbit$\n"
         " $field$.$setter$(static_cast<ArgT0 &&>(arg0),"
         " args..., GetArenaForAllocation());\n"
@@ -226,6 +227,7 @@ void StringFieldGenerator::GenerateInlineAccessorDefinitions(
         "template <typename ArgT0, typename... ArgT>\n"
         "inline PROTOBUF_ALWAYS_INLINE\n"
         "void $classname$::set_$name$(ArgT0&& arg0, ArgT... args) {\n"
+        "$maybe_prepare_split_message$"
         " $set_hasbit$\n"
         " $field$.$setter$(static_cast<ArgT0 &&>(arg0),"
         " args..., GetArenaForAllocation(), _internal_$name$_donated(), "
@@ -240,6 +242,7 @@ void StringFieldGenerator::GenerateInlineAccessorDefinitions(
   }
   format(
       "inline TProtoStringType* $classname$::mutable_$name$() {\n"
+      "$maybe_prepare_split_message$"
       "  TProtoStringType* _s = _internal_mutable_$name$();\n"
       "$annotate_mutable$"
       "  // @@protoc_insertion_point(field_mutable:$full_name$)\n"
@@ -280,6 +283,7 @@ void StringFieldGenerator::GenerateInlineAccessorDefinitions(
   format(
       "inline TProtoStringType* $classname$::$release_name$() {\n"
       "$annotate_release$"
+      "$maybe_prepare_split_message$"
       "  // @@protoc_insertion_point(field_release:$full_name$)\n");
 
   if (HasHasbit(descriptor_)) {
@@ -311,6 +315,7 @@ void StringFieldGenerator::GenerateInlineAccessorDefinitions(
   format(
       "}\n"
       "inline void $classname$::set_allocated_$name$(TProtoStringType* $name$) {\n"
+      "$maybe_prepare_split_message$"
       "  if ($name$ != nullptr) {\n"
       "    $set_hasbit$\n"
       "  } else {\n"
@@ -403,7 +408,7 @@ void StringFieldGenerator::GenerateMessageClearingCode(
 void StringFieldGenerator::GenerateMergingCode(io::Printer* printer) const {
   Formatter format(printer, variables_);
   // TODO(gpike): improve this
-  format("_internal_set_$name$(from._internal_$name$());\n");
+  format("_this->_internal_set_$name$(from._internal_$name$());\n");
 }
 
 void StringFieldGenerator::GenerateSwappingCode(io::Printer* printer) const {
@@ -440,12 +445,27 @@ void StringFieldGenerator::GenerateConstructorCode(io::Printer* printer) const {
   }
 }
 
+void StringFieldGenerator::GenerateCreateSplitMessageCode(
+    io::Printer* printer) const {
+  GOOGLE_CHECK(ShouldSplit(descriptor_, options_));
+  GOOGLE_CHECK(!inlined_);
+  Formatter format(printer, variables_);
+  format("ptr->$name$_.InitDefault();\n");
+  if (IsString(descriptor_, options_) &&
+      descriptor_->default_value_string().empty()) {
+    format(
+        "#ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING\n"
+        "  ptr->$name$_.Set(\"\", GetArenaForAllocation());\n"
+        "#endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING\n");
+  }
+}
+
 void StringFieldGenerator::GenerateCopyConstructorCode(
     io::Printer* printer) const {
   Formatter format(printer, variables_);
   GenerateConstructorCode(printer);
   if (inlined_) {
-    format("new (&$field$) ::_pbi::InlinedStringField();\n");
+    format("new (&_this->$field$) ::_pbi::InlinedStringField();\n");
   }
 
   if (HasHasbit(descriptor_)) {
@@ -458,13 +478,13 @@ void StringFieldGenerator::GenerateCopyConstructorCode(
 
   if (!inlined_) {
     format(
-        "$field$.Set(from._internal_$name$(), \n"
-        "  GetArenaForAllocation());\n");
+        "_this->$field$.Set(from._internal_$name$(), \n"
+        "  _this->GetArenaForAllocation());\n");
   } else {
     format(
-        "$field$.Set(from._internal_$name$(),\n"
-        "  GetArenaForAllocation(), _internal_$name$_donated(), "
-        "&$donating_states_word$, $mask_for_undonate$, this);\n");
+        "_this->$field$.Set(from._internal_$name$(),\n"
+        "  _this->GetArenaForAllocation(), _this->_internal_$name$_donated(), "
+        "&_this->$donating_states_word$, $mask_for_undonate$, _this);\n");
   }
 
   format.Outdent();
@@ -474,6 +494,10 @@ void StringFieldGenerator::GenerateCopyConstructorCode(
 void StringFieldGenerator::GenerateDestructorCode(io::Printer* printer) const {
   Formatter format(printer, variables_);
   if (!inlined_) {
+    if (ShouldSplit(descriptor_, options_)) {
+      format("$cached_split_ptr$->$name$_.Destroy();\n");
+      return;
+    }
     format("$field$.Destroy();\n");
     return;
   }
@@ -481,6 +505,7 @@ void StringFieldGenerator::GenerateDestructorCode(io::Printer* printer) const {
   // Destructor has been implicitly skipped as a union, and even the
   // message-owned arena is enabled, arena could still be missing for
   // Arena::CreateMessage(nullptr).
+  GOOGLE_DCHECK(!ShouldSplit(descriptor_, options_));
   format("$field$.~InlinedStringField();\n");
 }
 
@@ -522,22 +547,43 @@ void StringFieldGenerator::GenerateByteSize(io::Printer* printer) const {
       "    this->_internal_$name$());\n");
 }
 
-void StringFieldGenerator::GenerateConstinitInitializer(
+void StringFieldGenerator::GenerateConstexprAggregateInitializer(
     io::Printer* printer) const {
   Formatter format(printer, variables_);
   if (inlined_) {
-    format("$name$_(nullptr, false)");
+    format("/*decltype($field$)*/{nullptr, false}");
     return;
   }
   if (descriptor_->default_value_string().empty()) {
     format(
-        "$name$_(&::_pbi::fixed_address_empty_string, "
-        "::_pbi::ConstantInitialized{})");
+        "/*decltype($field$)*/{&::_pbi::fixed_address_empty_string, "
+        "::_pbi::ConstantInitialized{}}");
+  } else {
+    format("/*decltype($field$)*/{nullptr, ::_pbi::ConstantInitialized{}}");
+  }
+}
+
+void StringFieldGenerator::GenerateAggregateInitializer(
+    io::Printer* printer) const {
+  Formatter format(printer, variables_);
+  if (ShouldSplit(descriptor_, options_)) {
+    GOOGLE_CHECK(!inlined_);
+    format("decltype(Impl_::Split::$name$_){}");
+    return;
+  }
+  if (!inlined_) {
+    format("decltype($field$){}");
   } else {
-    format("$name$_(nullptr, ::_pbi::ConstantInitialized{})");
+    format("decltype($field$)(arena)");
   }
 }
 
+void StringFieldGenerator::GenerateCopyAggregateInitializer(
+    io::Printer* printer) const {
+  Formatter format(printer, variables_);
+  format("decltype($field$){}");
+}
+
 // ===================================================================
 
 StringOneofFieldGenerator::StringOneofFieldGenerator(
@@ -858,7 +904,7 @@ void RepeatedStringFieldGenerator::GenerateClearingCode(
 void RepeatedStringFieldGenerator::GenerateMergingCode(
     io::Printer* printer) const {
   Formatter format(printer, variables_);
-  format("$field$.MergeFrom(from.$field$);\n");
+  format("_this->$field$.MergeFrom(from.$field$);\n");
 }
 
 void RepeatedStringFieldGenerator::GenerateSwappingCode(
@@ -867,6 +913,12 @@ void RepeatedStringFieldGenerator::GenerateSwappingCode(
   format("$field$.InternalSwap(&other->$field$);\n");
 }
 
+void RepeatedStringFieldGenerator::GenerateDestructorCode(
+    io::Printer* printer) const {
+  Formatter format(printer, variables_);
+  format("$field$.~RepeatedPtrField();\n");
+}
+
 void RepeatedStringFieldGenerator::GenerateSerializeWithCachedSizesToArray(
     io::Printer* printer) const {
   Formatter format(printer, variables_);
@@ -899,12 +951,6 @@ void RepeatedStringFieldGenerator::GenerateByteSize(
       "}\n");
 }
 
-void RepeatedStringFieldGenerator::GenerateConstinitInitializer(
-    io::Printer* printer) const {
-  Formatter format(printer, variables_);
-  format("$name$_()");
-}
-
 }  // namespace cpp
 }  // namespace compiler
 }  // namespace protobuf
diff --git a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_string_field.h b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/string_field.h
index 845bf073a93..db5f18bfb7d 100644
--- a/contrib/libs/protoc/src/google/protobuf/compiler/cpp/cpp_string_field.h
+++ b/contrib/libs/protoc/src/google/protobuf/compiler/cpp/string_field.h
@@ -38,7 +38,7 @@
 #include <map>
 #include <string>
 
-#include <google/protobuf/compiler/cpp/cpp_field.h>
+#include <google/protobuf/compiler/cpp/field.h>
 
 namespace google {
 namespace protobuf {
@@ -63,13 +63,17 @@ class StringFieldGenerator : public FieldGenerator {
   void GenerateMergingCode(io::Printer* printer) const override;
   void GenerateSwappingCode(io::Printer* printer) const override;
   void GenerateConstructorCode(io::Printer* printer) const override;
+  void GenerateCreateSplitMessageCode(io::Printer* printer) const override;
   void GenerateCopyConstructorCode(io::Printer* printer) const override;
   void GenerateDestructorCode(io::Printer* printer) const override;
   void GenerateArenaDestructorCode(io::Printer* printer) const override;
   void GenerateSerializeWithCachedSizesToArray(
       io::Printer* printer) const override;
   void GenerateByteSize(io::Printer* printer) const override;
-  void GenerateConstinitInitializer(io::Printer* printer) const override;
+  void GenerateConstexprAggregateInitializer(
+      io::Printer* printer) const override;
+  void GenerateAggregateInitializer(io::Printer* printer) const override;
+  void GenerateCopyAggregateInitializer(io::Printer* printer) const override;
   bool IsInlined() const override { return inlined_; }
   ArenaDtorNeeds NeedsArenaDestructor() const override;
 
@@ -112,11 +116,13 @@ class RepeatedStringFieldGenerator : public FieldGenerator {
   void GenerateMergingCode(io::Printer* printer) const override;
   void GenerateSwappingCode(io::Printer* printer) const override;
   void GenerateConstructorCode(io::Printer* printer) const override {}
-  void GenerateCopyConstructorCode(io::Printer* printer) const override {}
+  void GenerateCopyConstructorCode(io::Printer*  /*printer*/) const override {
+    GOOGLE_CHECK(!ShouldSplit(descriptor_, options_));
+  }
+  void GenerateDestructorCode(io::Printer* printer) const override;
   void GenerateSerializeWithCachedSizesToArray(
       io::Printer* printer) const override;
   void GenerateByteSize(io::Printer* printer) const override;
-  void GenerateConstinitInitializer(io::Printer* printer) const override;
 
  private:
   GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(RepeatedStringFieldGenerator);