Add a swift_prefix file option.

Swift generators should default to CamelCasing the proto package and prefixing
symbols with that, but this option allows developers to override that behavior
with something custom if they desire.

Fixes https://github.com/google/protobuf/issues/1833

3 files changed, 334 insertions, 143 deletions

diff --git a/src/google/protobuf/descriptor.pb.cc b/src/google/protobuf/descriptor.pb.cc
index 846c2875..56e75fa4 100644
--- a/src/google/protobuf/descriptor.pb.cc
+++ b/src/google/protobuf/descriptor.pb.cc
@@ -251,22 +251,24 @@ const ::google::protobuf::uint32* protobuf_Offsets_google_2fprotobuf_2fdescripto
     GOOGLE_PROTOBUF_GENERATED_MESSAGE_FIELD_OFFSET(FileOptions, cc_enable_arenas_),
     GOOGLE_PROTOBUF_GENERATED_MESSAGE_FIELD_OFFSET(FileOptions, objc_class_prefix_),
     GOOGLE_PROTOBUF_GENERATED_MESSAGE_FIELD_OFFSET(FileOptions, csharp_namespace_),
+    GOOGLE_PROTOBUF_GENERATED_MESSAGE_FIELD_OFFSET(FileOptions, swift_prefix_),
     GOOGLE_PROTOBUF_GENERATED_MESSAGE_FIELD_OFFSET(FileOptions, uninterpreted_option_),
     0,
     1,
-    5,
     6,
     7,
-    13,
-    2,
     8,
+    14,
+    2,
     9,
     10,
     11,
     12,
+    13,
     3,
     4,
-    14,
+    5,
+    15,
     GOOGLE_PROTOBUF_GENERATED_MESSAGE_FIELD_OFFSET(MessageOptions, _has_bits_),
     GOOGLE_PROTOBUF_GENERATED_MESSAGE_FIELD_OFFSET(MessageOptions, _internal_metadata_),
     GOOGLE_PROTOBUF_GENERATED_MESSAGE_FIELD_OFFSET(MessageOptions, _extensions_),
@@ -421,20 +423,20 @@ static const ::google::protobuf::internal::MigrationSchema schemas[] = {
   { 116, 123, sizeof(EnumValueDescriptorProto)},
   { 126, 133, sizeof(ServiceDescriptorProto)},
   { 136, 146, sizeof(MethodDescriptorProto)},
-  { 152, 171, sizeof(FileOptions)},
-  { 186, 195, sizeof(MessageOptions)},
-  { 200, 211, sizeof(FieldOptions)},
-  { 218, 223, sizeof(OneofOptions)},
-  { 224, 231, sizeof(EnumOptions)},
-  { 234, 240, sizeof(EnumValueOptions)},
-  { 242, 248, sizeof(ServiceOptions)},
-  { 250, 257, sizeof(MethodOptions)},
-  { 260, 266, sizeof(UninterpretedOption_NamePart)},
-  { 268, 279, sizeof(UninterpretedOption)},
-  { 286, 295, sizeof(SourceCodeInfo_Location)},
-  { 300, 305, sizeof(SourceCodeInfo)},
-  { 306, 314, sizeof(GeneratedCodeInfo_Annotation)},
-  { 318, 323, sizeof(GeneratedCodeInfo)},
+  { 152, 172, sizeof(FileOptions)},
+  { 188, 197, sizeof(MessageOptions)},
+  { 202, 213, sizeof(FieldOptions)},
+  { 220, 225, sizeof(OneofOptions)},
+  { 226, 233, sizeof(EnumOptions)},
+  { 236, 242, sizeof(EnumValueOptions)},
+  { 244, 250, sizeof(ServiceOptions)},
+  { 252, 259, sizeof(MethodOptions)},
+  { 262, 268, sizeof(UninterpretedOption_NamePart)},
+  { 270, 281, sizeof(UninterpretedOption)},
+  { 288, 297, sizeof(SourceCodeInfo_Location)},
+  { 302, 307, sizeof(SourceCodeInfo)},
+  { 308, 316, sizeof(GeneratedCodeInfo_Annotation)},
+  { 320, 325, sizeof(GeneratedCodeInfo)},
 };
 
 static const ::google::protobuf::internal::DefaultInstanceData file_default_instances[] = {
@@ -662,7 +664,7 @@ void protobuf_AddDesc_google_2fprotobuf_2fdescriptor_2eproto_impl() {
       "\n\013output_type\030\003 \001(\t\022/\n\007options\030\004 \001(\0132\036.g"
       "oogle.protobuf.MethodOptions\022\037\n\020client_s"
       "treaming\030\005 \001(\010:\005false\022\037\n\020server_streamin"
-      "g\030\006 \001(\010:\005false\"\204\005\n\013FileOptions\022\024\n\014java_p"
+      "g\030\006 \001(\010:\005false\"\232\005\n\013FileOptions\022\024\n\014java_p"
       "ackage\030\001 \001(\t\022\034\n\024java_outer_classname\030\010 \001"
       "(\t\022\"\n\023java_multiple_files\030\n \001(\010:\005false\022)"
       "\n\035java_generate_equals_and_hash\030\024 \001(\010B\002\030"
@@ -674,69 +676,70 @@ void protobuf_AddDesc_google_2fprotobuf_2fdescriptor_2eproto_impl() {
       "\005false\022\"\n\023py_generic_services\030\022 \001(\010:\005fal"
       "se\022\031\n\ndeprecated\030\027 \001(\010:\005false\022\037\n\020cc_enab"
       "le_arenas\030\037 \001(\010:\005false\022\031\n\021objc_class_pre"
-      "fix\030$ \001(\t\022\030\n\020csharp_namespace\030% \001(\t\022C\n\024u"
+      "fix\030$ \001(\t\022\030\n\020csharp_namespace\030% \001(\t\022\024\n\014s"
+      "wift_prefix\030\' \001(\t\022C\n\024uninterpreted_optio"
+      "n\030\347\007 \003(\0132$.google.protobuf.Uninterpreted"
+      "Option\":\n\014OptimizeMode\022\t\n\005SPEED\020\001\022\r\n\tCOD"
+      "E_SIZE\020\002\022\020\n\014LITE_RUNTIME\020\003*\t\010\350\007\020\200\200\200\200\002J\004\010"
+      "&\020\'\"\354\001\n\016MessageOptions\022&\n\027message_set_wi"
+      "re_format\030\001 \001(\010:\005false\022.\n\037no_standard_de"
+      "scriptor_accessor\030\002 \001(\010:\005false\022\031\n\ndeprec"
+      "ated\030\003 \001(\010:\005false\022\021\n\tmap_entry\030\007 \001(\010\022C\n\024"
+      "uninterpreted_option\030\347\007 \003(\0132$.google.pro"
+      "tobuf.UninterpretedOption*\t\010\350\007\020\200\200\200\200\002J\004\010\010"
+      "\020\t\"\236\003\n\014FieldOptions\022:\n\005ctype\030\001 \001(\0162#.goo"
+      "gle.protobuf.FieldOptions.CType:\006STRING\022"
+      "\016\n\006packed\030\002 \001(\010\022\?\n\006jstype\030\006 \001(\0162$.google"
+      ".protobuf.FieldOptions.JSType:\tJS_NORMAL"
+      "\022\023\n\004lazy\030\005 \001(\010:\005false\022\031\n\ndeprecated\030\003 \001("
+      "\010:\005false\022\023\n\004weak\030\n \001(\010:\005false\022C\n\024uninter"
+      "preted_option\030\347\007 \003(\0132$.google.protobuf.U"
+      "ninterpretedOption\"/\n\005CType\022\n\n\006STRING\020\000\022"
+      "\010\n\004CORD\020\001\022\020\n\014STRING_PIECE\020\002\"5\n\006JSType\022\r\n"
+      "\tJS_NORMAL\020\000\022\r\n\tJS_STRING\020\001\022\r\n\tJS_NUMBER"
+      "\020\002*\t\010\350\007\020\200\200\200\200\002J\004\010\004\020\005\"^\n\014OneofOptions\022C\n\024u"
       "ninterpreted_option\030\347\007 \003(\0132$.google.prot"
-      "obuf.UninterpretedOption\":\n\014OptimizeMode"
-      "\022\t\n\005SPEED\020\001\022\r\n\tCODE_SIZE\020\002\022\020\n\014LITE_RUNTI"
-      "ME\020\003*\t\010\350\007\020\200\200\200\200\002J\004\010&\020\'\"\354\001\n\016MessageOptions"
-      "\022&\n\027message_set_wire_format\030\001 \001(\010:\005false"
-      "\022.\n\037no_standard_descriptor_accessor\030\002 \001("
-      "\010:\005false\022\031\n\ndeprecated\030\003 \001(\010:\005false\022\021\n\tm"
-      "ap_entry\030\007 \001(\010\022C\n\024uninterpreted_option\030\347"
-      "\007 \003(\0132$.google.protobuf.UninterpretedOpt"
-      "ion*\t\010\350\007\020\200\200\200\200\002J\004\010\010\020\t\"\236\003\n\014FieldOptions\022:\n"
-      "\005ctype\030\001 \001(\0162#.google.protobuf.FieldOpti"
-      "ons.CType:\006STRING\022\016\n\006packed\030\002 \001(\010\022\?\n\006jst"
-      "ype\030\006 \001(\0162$.google.protobuf.FieldOptions"
-      ".JSType:\tJS_NORMAL\022\023\n\004lazy\030\005 \001(\010:\005false\022"
-      "\031\n\ndeprecated\030\003 \001(\010:\005false\022\023\n\004weak\030\n \001(\010"
-      ":\005false\022C\n\024uninterpreted_option\030\347\007 \003(\0132$"
-      ".google.protobuf.UninterpretedOption\"/\n\005"
-      "CType\022\n\n\006STRING\020\000\022\010\n\004CORD\020\001\022\020\n\014STRING_PI"
-      "ECE\020\002\"5\n\006JSType\022\r\n\tJS_NORMAL\020\000\022\r\n\tJS_STR"
-      "ING\020\001\022\r\n\tJS_NUMBER\020\002*\t\010\350\007\020\200\200\200\200\002J\004\010\004\020\005\"^\n"
-      "\014OneofOptions\022C\n\024uninterpreted_option\030\347\007"
-      " \003(\0132$.google.protobuf.UninterpretedOpti"
-      "on*\t\010\350\007\020\200\200\200\200\002\"\215\001\n\013EnumOptions\022\023\n\013allow_a"
-      "lias\030\002 \001(\010\022\031\n\ndeprecated\030\003 \001(\010:\005false\022C\n"
-      "\024uninterpreted_option\030\347\007 \003(\0132$.google.pr"
-      "otobuf.UninterpretedOption*\t\010\350\007\020\200\200\200\200\002\"}\n"
-      "\020EnumValueOptions\022\031\n\ndeprecated\030\001 \001(\010:\005f"
-      "alse\022C\n\024uninterpreted_option\030\347\007 \003(\0132$.go"
-      "ogle.protobuf.UninterpretedOption*\t\010\350\007\020\200"
-      "\200\200\200\002\"{\n\016ServiceOptions\022\031\n\ndeprecated\030! \001"
-      "(\010:\005false\022C\n\024uninterpreted_option\030\347\007 \003(\013"
-      "2$.google.protobuf.UninterpretedOption*\t"
-      "\010\350\007\020\200\200\200\200\002\"\255\002\n\rMethodOptions\022\031\n\ndeprecate"
-      "d\030! \001(\010:\005false\022_\n\021idempotency_level\030\" \001("
-      "\0162/.google.protobuf.MethodOptions.Idempo"
-      "tencyLevel:\023IDEMPOTENCY_UNKNOWN\022C\n\024unint"
+      "obuf.UninterpretedOption*\t\010\350\007\020\200\200\200\200\002\"\215\001\n\013"
+      "EnumOptions\022\023\n\013allow_alias\030\002 \001(\010\022\031\n\ndepr"
+      "ecated\030\003 \001(\010:\005false\022C\n\024uninterpreted_opt"
+      "ion\030\347\007 \003(\0132$.google.protobuf.Uninterpret"
+      "edOption*\t\010\350\007\020\200\200\200\200\002\"}\n\020EnumValueOptions\022"
+      "\031\n\ndeprecated\030\001 \001(\010:\005false\022C\n\024uninterpre"
+      "ted_option\030\347\007 \003(\0132$.google.protobuf.Unin"
+      "terpretedOption*\t\010\350\007\020\200\200\200\200\002\"{\n\016ServiceOpt"
+      "ions\022\031\n\ndeprecated\030! \001(\010:\005false\022C\n\024unint"
       "erpreted_option\030\347\007 \003(\0132$.google.protobuf"
-      ".UninterpretedOption\"P\n\020IdempotencyLevel"
-      "\022\027\n\023IDEMPOTENCY_UNKNOWN\020\000\022\023\n\017NO_SIDE_EFF"
-      "ECTS\020\001\022\016\n\nIDEMPOTENT\020\002*\t\010\350\007\020\200\200\200\200\002\"\236\002\n\023Un"
-      "interpretedOption\022;\n\004name\030\002 \003(\0132-.google"
-      ".protobuf.UninterpretedOption.NamePart\022\030"
-      "\n\020identifier_value\030\003 \001(\t\022\032\n\022positive_int"
-      "_value\030\004 \001(\004\022\032\n\022negative_int_value\030\005 \001(\003"
-      "\022\024\n\014double_value\030\006 \001(\001\022\024\n\014string_value\030\007"
-      " \001(\014\022\027\n\017aggregate_value\030\010 \001(\t\0323\n\010NamePar"
-      "t\022\021\n\tname_part\030\001 \002(\t\022\024\n\014is_extension\030\002 \002"
-      "(\010\"\325\001\n\016SourceCodeInfo\022:\n\010location\030\001 \003(\0132"
-      "(.google.protobuf.SourceCodeInfo.Locatio"
-      "n\032\206\001\n\010Location\022\020\n\004path\030\001 \003(\005B\002\020\001\022\020\n\004span"
-      "\030\002 \003(\005B\002\020\001\022\030\n\020leading_comments\030\003 \001(\t\022\031\n\021"
-      "trailing_comments\030\004 \001(\t\022!\n\031leading_detac"
-      "hed_comments\030\006 \003(\t\"\247\001\n\021GeneratedCodeInfo"
-      "\022A\n\nannotation\030\001 \003(\0132-.google.protobuf.G"
-      "eneratedCodeInfo.Annotation\032O\n\nAnnotatio"
-      "n\022\020\n\004path\030\001 \003(\005B\002\020\001\022\023\n\013source_file\030\002 \001(\t"
-      "\022\r\n\005begin\030\003 \001(\005\022\013\n\003end\030\004 \001(\005BX\n\023com.goog"
-      "le.protobufB\020DescriptorProtosH\001Z\ndescrip"
-      "tor\242\002\003GPB\252\002\032Google.Protobuf.Reflection"
+      ".UninterpretedOption*\t\010\350\007\020\200\200\200\200\002\"\255\002\n\rMeth"
+      "odOptions\022\031\n\ndeprecated\030! \001(\010:\005false\022_\n\021"
+      "idempotency_level\030\" \001(\0162/.google.protobu"
+      "f.MethodOptions.IdempotencyLevel:\023IDEMPO"
+      "TENCY_UNKNOWN\022C\n\024uninterpreted_option\030\347\007"
+      " \003(\0132$.google.protobuf.UninterpretedOpti"
+      "on\"P\n\020IdempotencyLevel\022\027\n\023IDEMPOTENCY_UN"
+      "KNOWN\020\000\022\023\n\017NO_SIDE_EFFECTS\020\001\022\016\n\nIDEMPOTE"
+      "NT\020\002*\t\010\350\007\020\200\200\200\200\002\"\236\002\n\023UninterpretedOption\022"
+      ";\n\004name\030\002 \003(\0132-.google.protobuf.Uninterp"
+      "retedOption.NamePart\022\030\n\020identifier_value"
+      "\030\003 \001(\t\022\032\n\022positive_int_value\030\004 \001(\004\022\032\n\022ne"
+      "gative_int_value\030\005 \001(\003\022\024\n\014double_value\030\006"
+      " \001(\001\022\024\n\014string_value\030\007 \001(\014\022\027\n\017aggregate_"
+      "value\030\010 \001(\t\0323\n\010NamePart\022\021\n\tname_part\030\001 \002"
+      "(\t\022\024\n\014is_extension\030\002 \002(\010\"\325\001\n\016SourceCodeI"
+      "nfo\022:\n\010location\030\001 \003(\0132(.google.protobuf."
+      "SourceCodeInfo.Location\032\206\001\n\010Location\022\020\n\004"
+      "path\030\001 \003(\005B\002\020\001\022\020\n\004span\030\002 \003(\005B\002\020\001\022\030\n\020lead"
+      "ing_comments\030\003 \001(\t\022\031\n\021trailing_comments\030"
+      "\004 \001(\t\022!\n\031leading_detached_comments\030\006 \003(\t"
+      "\"\247\001\n\021GeneratedCodeInfo\022A\n\nannotation\030\001 \003"
+      "(\0132-.google.protobuf.GeneratedCodeInfo.A"
+      "nnotation\032O\n\nAnnotation\022\020\n\004path\030\001 \003(\005B\002\020"
+      "\001\022\023\n\013source_file\030\002 \001(\t\022\r\n\005begin\030\003 \001(\005\022\013\n"
+      "\003end\030\004 \001(\005BX\n\023com.google.protobufB\020Descr"
+      "iptorProtosH\001Z\ndescriptor\242\002\003GPB\252\002\032Google"
+      ".Protobuf.Reflection"
   };
   ::google::protobuf::DescriptorPool::InternalAddGeneratedFile(
-      descriptor, 5478);
+      descriptor, 5500);
   ::google::protobuf::MessageFactory::InternalRegisterGeneratedFile(
     "google/protobuf/descriptor.proto", &protobuf_RegisterTypes);
   ::google::protobuf::internal::OnShutdown(&protobuf_ShutdownFile_google_2fprotobuf_2fdescriptor_2eproto);
@@ -7871,6 +7874,7 @@ const int FileOptions::kDeprecatedFieldNumber;
 const int FileOptions::kCcEnableArenasFieldNumber;
 const int FileOptions::kObjcClassPrefixFieldNumber;
 const int FileOptions::kCsharpNamespaceFieldNumber;
+const int FileOptions::kSwiftPrefixFieldNumber;
 const int FileOptions::kUninterpretedOptionFieldNumber;
 #endif  // !defined(_MSC_VER) || _MSC_VER >= 1900
 
@@ -7910,6 +7914,10 @@ FileOptions::FileOptions(const FileOptions& from)
   if (from.has_csharp_namespace()) {
     csharp_namespace_.AssignWithDefault(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), from.csharp_namespace_);
   }
+  swift_prefix_.UnsafeSetDefault(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+  if (from.has_swift_prefix()) {
+    swift_prefix_.AssignWithDefault(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), from.swift_prefix_);
+  }
   ::memcpy(&java_multiple_files_, &from.java_multiple_files_,
     reinterpret_cast<char*>(&optimize_for_) -
     reinterpret_cast<char*>(&java_multiple_files_) + sizeof(optimize_for_));
@@ -7923,6 +7931,7 @@ void FileOptions::SharedCtor() {
   go_package_.UnsafeSetDefault(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
   objc_class_prefix_.UnsafeSetDefault(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
   csharp_namespace_.UnsafeSetDefault(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+  swift_prefix_.UnsafeSetDefault(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
   ::memset(&java_multiple_files_, 0, reinterpret_cast<char*>(&cc_enable_arenas_) -
     reinterpret_cast<char*>(&java_multiple_files_) + sizeof(cc_enable_arenas_));
   optimize_for_ = 1;
@@ -7939,6 +7948,7 @@ void FileOptions::SharedDtor() {
   go_package_.DestroyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
   objc_class_prefix_.DestroyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
   csharp_namespace_.DestroyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+  swift_prefix_.DestroyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 
 void FileOptions::SetCachedSize(int size) const {
@@ -7968,7 +7978,7 @@ void FileOptions::Clear() {
 // @@protoc_insertion_point(message_clear_start:google.protobuf.FileOptions)
   _extensions_.Clear();
   uninterpreted_option_.Clear();
-  if (_has_bits_[0 / 32] & 31u) {
+  if (_has_bits_[0 / 32] & 63u) {
     if (has_java_package()) {
       GOOGLE_DCHECK(!java_package_.IsDefault(&::google::protobuf::internal::GetEmptyStringAlreadyInited()));
       (*java_package_.UnsafeRawStringPointer())->clear();
@@ -7989,14 +7999,18 @@ void FileOptions::Clear() {
       GOOGLE_DCHECK(!csharp_namespace_.IsDefault(&::google::protobuf::internal::GetEmptyStringAlreadyInited()));
       (*csharp_namespace_.UnsafeRawStringPointer())->clear();
     }
+    if (has_swift_prefix()) {
+      GOOGLE_DCHECK(!swift_prefix_.IsDefault(&::google::protobuf::internal::GetEmptyStringAlreadyInited()));
+      (*swift_prefix_.UnsafeRawStringPointer())->clear();
+    }
   }
-  if (_has_bits_[0 / 32] & 224u) {
-    ::memset(&java_multiple_files_, 0, reinterpret_cast<char*>(&java_string_check_utf8_) -
-      reinterpret_cast<char*>(&java_multiple_files_) + sizeof(java_string_check_utf8_));
+  if (_has_bits_[0 / 32] & 192u) {
+    ::memset(&java_multiple_files_, 0, reinterpret_cast<char*>(&java_generate_equals_and_hash_) -
+      reinterpret_cast<char*>(&java_multiple_files_) + sizeof(java_generate_equals_and_hash_));
   }
-  if (_has_bits_[8 / 32] & 16128u) {
-    ::memset(&cc_generic_services_, 0, reinterpret_cast<char*>(&cc_enable_arenas_) -
-      reinterpret_cast<char*>(&cc_generic_services_) + sizeof(cc_enable_arenas_));
+  if (_has_bits_[8 / 32] & 32512u) {
+    ::memset(&java_string_check_utf8_, 0, reinterpret_cast<char*>(&cc_enable_arenas_) -
+      reinterpret_cast<char*>(&java_string_check_utf8_) + sizeof(cc_enable_arenas_));
     optimize_for_ = 1;
   }
   _has_bits_.Clear();
@@ -8210,6 +8224,21 @@ bool FileOptions::MergePartialFromCodedStream(
         break;
       }
 
+      // optional string swift_prefix = 39;
+      case 39: {
+        if (tag == 314u) {
+          DO_(::google::protobuf::internal::WireFormatLite::ReadString(
+                input, this->mutable_swift_prefix()));
+          ::google::protobuf::internal::WireFormat::VerifyUTF8StringNamedField(
+            this->swift_prefix().data(), this->swift_prefix().length(),
+            ::google::protobuf::internal::WireFormat::PARSE,
+            "google.protobuf.FileOptions.swift_prefix");
+        } else {
+          goto handle_unusual;
+        }
+        break;
+      }
+
       // repeated .google.protobuf.UninterpretedOption uninterpreted_option = 999;
       case 999: {
         if (tag == 7994u) {
@@ -8349,6 +8378,16 @@ void FileOptions::SerializeWithCachedSizes(
       37, this->csharp_namespace(), output);
   }
 
+  // optional string swift_prefix = 39;
+  if (has_swift_prefix()) {
+    ::google::protobuf::internal::WireFormat::VerifyUTF8StringNamedField(
+      this->swift_prefix().data(), this->swift_prefix().length(),
+      ::google::protobuf::internal::WireFormat::SERIALIZE,
+      "google.protobuf.FileOptions.swift_prefix");
+    ::google::protobuf::internal::WireFormatLite::WriteStringMaybeAliased(
+      39, this->swift_prefix(), output);
+  }
+
   // repeated .google.protobuf.UninterpretedOption uninterpreted_option = 999;
   for (unsigned int i = 0, n = this->uninterpreted_option_size(); i < n; i++) {
     ::google::protobuf::internal::WireFormatLite::WriteMessageMaybeToArray(
@@ -8471,6 +8510,17 @@ void FileOptions::SerializeWithCachedSizes(
         37, this->csharp_namespace(), target);
   }
 
+  // optional string swift_prefix = 39;
+  if (has_swift_prefix()) {
+    ::google::protobuf::internal::WireFormat::VerifyUTF8StringNamedField(
+      this->swift_prefix().data(), this->swift_prefix().length(),
+      ::google::protobuf::internal::WireFormat::SERIALIZE,
+      "google.protobuf.FileOptions.swift_prefix");
+    target =
+      ::google::protobuf::internal::WireFormatLite::WriteStringToArray(
+        39, this->swift_prefix(), target);
+  }
+
   // repeated .google.protobuf.UninterpretedOption uninterpreted_option = 999;
   for (unsigned int i = 0, n = this->uninterpreted_option_size(); i < n; i++) {
     target = ::google::protobuf::internal::WireFormatLite::
@@ -8548,6 +8598,13 @@ size_t FileOptions::ByteSizeLong() const {
           this->csharp_namespace());
     }
 
+    // optional string swift_prefix = 39;
+    if (has_swift_prefix()) {
+      total_size += 2 +
+        ::google::protobuf::internal::WireFormatLite::StringSize(
+          this->swift_prefix());
+    }
+
     // optional bool java_multiple_files = 10 [default = false];
     if (has_java_multiple_files()) {
       total_size += 1 + 1;
@@ -8558,13 +8615,13 @@ size_t FileOptions::ByteSizeLong() const {
       total_size += 2 + 1;
     }
 
+  }
+  if (_has_bits_[8 / 32] & 32512u) {
     // optional bool java_string_check_utf8 = 27 [default = false];
     if (has_java_string_check_utf8()) {
       total_size += 2 + 1;
     }
 
-  }
-  if (_has_bits_[8 / 32] & 16128u) {
     // optional bool cc_generic_services = 16 [default = false];
     if (has_cc_generic_services()) {
       total_size += 2 + 1;
@@ -8646,17 +8703,21 @@ void FileOptions::MergeFrom(const FileOptions& from) {
       set_has_csharp_namespace();
       csharp_namespace_.AssignWithDefault(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), from.csharp_namespace_);
     }
+    if (from.has_swift_prefix()) {
+      set_has_swift_prefix();
+      swift_prefix_.AssignWithDefault(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), from.swift_prefix_);
+    }
     if (from.has_java_multiple_files()) {
       set_java_multiple_files(from.java_multiple_files());
     }
     if (from.has_java_generate_equals_and_hash()) {
       set_java_generate_equals_and_hash(from.java_generate_equals_and_hash());
     }
+  }
+  if (from._has_bits_[8 / 32] & 32512u) {
     if (from.has_java_string_check_utf8()) {
       set_java_string_check_utf8(from.java_string_check_utf8());
     }
-  }
-  if (from._has_bits_[8 / 32] & 16128u) {
     if (from.has_cc_generic_services()) {
       set_cc_generic_services(from.cc_generic_services());
     }
@@ -8712,6 +8773,7 @@ void FileOptions::InternalSwap(FileOptions* other) {
   go_package_.Swap(&other->go_package_);
   objc_class_prefix_.Swap(&other->objc_class_prefix_);
   csharp_namespace_.Swap(&other->csharp_namespace_);
+  swift_prefix_.Swap(&other->swift_prefix_);
   std::swap(java_multiple_files_, other->java_multiple_files_);
   std::swap(java_generate_equals_and_hash_, other->java_generate_equals_and_hash_);
   std::swap(java_string_check_utf8_, other->java_string_check_utf8_);
@@ -8845,13 +8907,13 @@ void FileOptions::set_allocated_java_outer_classname(::std::string* java_outer_c
 
 // optional bool java_multiple_files = 10 [default = false];
 bool FileOptions::has_java_multiple_files() const {
-  return (_has_bits_[0] & 0x00000020u) != 0;
+  return (_has_bits_[0] & 0x00000040u) != 0;
 }
 void FileOptions::set_has_java_multiple_files() {
-  _has_bits_[0] |= 0x00000020u;
+  _has_bits_[0] |= 0x00000040u;
 }
 void FileOptions::clear_has_java_multiple_files() {
-  _has_bits_[0] &= ~0x00000020u;
+  _has_bits_[0] &= ~0x00000040u;
 }
 void FileOptions::clear_java_multiple_files() {
   java_multiple_files_ = false;
@@ -8869,13 +8931,13 @@ void FileOptions::set_java_multiple_files(bool value) {
 
 // optional bool java_generate_equals_and_hash = 20 [deprecated = true];
 bool FileOptions::has_java_generate_equals_and_hash() const {
-  return (_has_bits_[0] & 0x00000040u) != 0;
+  return (_has_bits_[0] & 0x00000080u) != 0;
 }
 void FileOptions::set_has_java_generate_equals_and_hash() {
-  _has_bits_[0] |= 0x00000040u;
+  _has_bits_[0] |= 0x00000080u;
 }
 void FileOptions::clear_has_java_generate_equals_and_hash() {
-  _has_bits_[0] &= ~0x00000040u;
+  _has_bits_[0] &= ~0x00000080u;
 }
 void FileOptions::clear_java_generate_equals_and_hash() {
   java_generate_equals_and_hash_ = false;
@@ -8893,13 +8955,13 @@ void FileOptions::set_java_generate_equals_and_hash(bool value) {
 
 // optional bool java_string_check_utf8 = 27 [default = false];
 bool FileOptions::has_java_string_check_utf8() const {
-  return (_has_bits_[0] & 0x00000080u) != 0;
+  return (_has_bits_[0] & 0x00000100u) != 0;
 }
 void FileOptions::set_has_java_string_check_utf8() {
-  _has_bits_[0] |= 0x00000080u;
+  _has_bits_[0] |= 0x00000100u;
 }
 void FileOptions::clear_has_java_string_check_utf8() {
-  _has_bits_[0] &= ~0x00000080u;
+  _has_bits_[0] &= ~0x00000100u;
 }
 void FileOptions::clear_java_string_check_utf8() {
   java_string_check_utf8_ = false;
@@ -8917,13 +8979,13 @@ void FileOptions::set_java_string_check_utf8(bool value) {
 
 // optional .google.protobuf.FileOptions.OptimizeMode optimize_for = 9 [default = SPEED];
 bool FileOptions::has_optimize_for() const {
-  return (_has_bits_[0] & 0x00002000u) != 0;
+  return (_has_bits_[0] & 0x00004000u) != 0;
 }
 void FileOptions::set_has_optimize_for() {
-  _has_bits_[0] |= 0x00002000u;
+  _has_bits_[0] |= 0x00004000u;
 }
 void FileOptions::clear_has_optimize_for() {
-  _has_bits_[0] &= ~0x00002000u;
+  _has_bits_[0] &= ~0x00004000u;
 }
 void FileOptions::clear_optimize_for() {
   optimize_for_ = 1;
@@ -8996,13 +9058,13 @@ void FileOptions::set_allocated_go_package(::std::string* go_package) {
 
 // optional bool cc_generic_services = 16 [default = false];
 bool FileOptions::has_cc_generic_services() const {
-  return (_has_bits_[0] & 0x00000100u) != 0;
+  return (_has_bits_[0] & 0x00000200u) != 0;
 }
 void FileOptions::set_has_cc_generic_services() {
-  _has_bits_[0] |= 0x00000100u;
+  _has_bits_[0] |= 0x00000200u;
 }
 void FileOptions::clear_has_cc_generic_services() {
-  _has_bits_[0] &= ~0x00000100u;
+  _has_bits_[0] &= ~0x00000200u;
 }
 void FileOptions::clear_cc_generic_services() {
   cc_generic_services_ = false;
@@ -9020,13 +9082,13 @@ void FileOptions::set_cc_generic_services(bool value) {
 
 // optional bool java_generic_services = 17 [default = false];
 bool FileOptions::has_java_generic_services() const {
-  return (_has_bits_[0] & 0x00000200u) != 0;
+  return (_has_bits_[0] & 0x00000400u) != 0;
 }
 void FileOptions::set_has_java_generic_services() {
-  _has_bits_[0] |= 0x00000200u;
+  _has_bits_[0] |= 0x00000400u;
 }
 void FileOptions::clear_has_java_generic_services() {
-  _has_bits_[0] &= ~0x00000200u;
+  _has_bits_[0] &= ~0x00000400u;
 }
 void FileOptions::clear_java_generic_services() {
   java_generic_services_ = false;
@@ -9044,13 +9106,13 @@ void FileOptions::set_java_generic_services(bool value) {
 
 // optional bool py_generic_services = 18 [default = false];
 bool FileOptions::has_py_generic_services() const {
-  return (_has_bits_[0] & 0x00000400u) != 0;
+  return (_has_bits_[0] & 0x00000800u) != 0;
 }
 void FileOptions::set_has_py_generic_services() {
-  _has_bits_[0] |= 0x00000400u;
+  _has_bits_[0] |= 0x00000800u;
 }
 void FileOptions::clear_has_py_generic_services() {
-  _has_bits_[0] &= ~0x00000400u;
+  _has_bits_[0] &= ~0x00000800u;
 }
 void FileOptions::clear_py_generic_services() {
   py_generic_services_ = false;
@@ -9068,13 +9130,13 @@ void FileOptions::set_py_generic_services(bool value) {
 
 // optional bool deprecated = 23 [default = false];
 bool FileOptions::has_deprecated() const {
-  return (_has_bits_[0] & 0x00000800u) != 0;
+  return (_has_bits_[0] & 0x00001000u) != 0;
 }
 void FileOptions::set_has_deprecated() {
-  _has_bits_[0] |= 0x00000800u;
+  _has_bits_[0] |= 0x00001000u;
 }
 void FileOptions::clear_has_deprecated() {
-  _has_bits_[0] &= ~0x00000800u;
+  _has_bits_[0] &= ~0x00001000u;
 }
 void FileOptions::clear_deprecated() {
   deprecated_ = false;
@@ -9092,13 +9154,13 @@ void FileOptions::set_deprecated(bool value) {
 
 // optional bool cc_enable_arenas = 31 [default = false];
 bool FileOptions::has_cc_enable_arenas() const {
-  return (_has_bits_[0] & 0x00001000u) != 0;
+  return (_has_bits_[0] & 0x00002000u) != 0;
 }
 void FileOptions::set_has_cc_enable_arenas() {
-  _has_bits_[0] |= 0x00001000u;
+  _has_bits_[0] |= 0x00002000u;
 }
 void FileOptions::clear_has_cc_enable_arenas() {
-  _has_bits_[0] &= ~0x00001000u;
+  _has_bits_[0] &= ~0x00002000u;
 }
 void FileOptions::clear_cc_enable_arenas() {
   cc_enable_arenas_ = false;
@@ -9222,6 +9284,60 @@ void FileOptions::set_allocated_csharp_namespace(::std::string* csharp_namespace
   // @@protoc_insertion_point(field_set_allocated:google.protobuf.FileOptions.csharp_namespace)
 }
 
+// optional string swift_prefix = 39;
+bool FileOptions::has_swift_prefix() const {
+  return (_has_bits_[0] & 0x00000020u) != 0;
+}
+void FileOptions::set_has_swift_prefix() {
+  _has_bits_[0] |= 0x00000020u;
+}
+void FileOptions::clear_has_swift_prefix() {
+  _has_bits_[0] &= ~0x00000020u;
+}
+void FileOptions::clear_swift_prefix() {
+  swift_prefix_.ClearToEmptyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+  clear_has_swift_prefix();
+}
+const ::std::string& FileOptions::swift_prefix() const {
+  // @@protoc_insertion_point(field_get:google.protobuf.FileOptions.swift_prefix)
+  return swift_prefix_.GetNoArena();
+}
+void FileOptions::set_swift_prefix(const ::std::string& value) {
+  set_has_swift_prefix();
+  swift_prefix_.SetNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), value);
+  // @@protoc_insertion_point(field_set:google.protobuf.FileOptions.swift_prefix)
+}
+void FileOptions::set_swift_prefix(const char* value) {
+  set_has_swift_prefix();
+  swift_prefix_.SetNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), ::std::string(value));
+  // @@protoc_insertion_point(field_set_char:google.protobuf.FileOptions.swift_prefix)
+}
+void FileOptions::set_swift_prefix(const char* value, size_t size) {
+  set_has_swift_prefix();
+  swift_prefix_.SetNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited(),
+      ::std::string(reinterpret_cast<const char*>(value), size));
+  // @@protoc_insertion_point(field_set_pointer:google.protobuf.FileOptions.swift_prefix)
+}
+::std::string* FileOptions::mutable_swift_prefix() {
+  set_has_swift_prefix();
+  // @@protoc_insertion_point(field_mutable:google.protobuf.FileOptions.swift_prefix)
+  return swift_prefix_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+}
+::std::string* FileOptions::release_swift_prefix() {
+  // @@protoc_insertion_point(field_release:google.protobuf.FileOptions.swift_prefix)
+  clear_has_swift_prefix();
+  return swift_prefix_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+}
+void FileOptions::set_allocated_swift_prefix(::std::string* swift_prefix) {
+  if (swift_prefix != NULL) {
+    set_has_swift_prefix();
+  } else {
+    clear_has_swift_prefix();
+  }
+  swift_prefix_.SetAllocatedNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), swift_prefix);
+  // @@protoc_insertion_point(field_set_allocated:google.protobuf.FileOptions.swift_prefix)
+}
+
 // repeated .google.protobuf.UninterpretedOption uninterpreted_option = 999;
 int FileOptions::uninterpreted_option_size() const {
   return uninterpreted_option_.size();
diff --git a/src/google/protobuf/descriptor.pb.h b/src/google/protobuf/descriptor.pb.h
index 7c3de2d2..00956cbf 100644
--- a/src/google/protobuf/descriptor.pb.h
+++ b/src/google/protobuf/descriptor.pb.h
@@ -2235,6 +2235,18 @@ class LIBPROTOBUF_EXPORT FileOptions : public ::google::protobuf::Message /* @@p
   ::std::string* release_csharp_namespace();
   void set_allocated_csharp_namespace(::std::string* csharp_namespace);
 
+  // optional string swift_prefix = 39;
+  bool has_swift_prefix() const;
+  void clear_swift_prefix();
+  static const int kSwiftPrefixFieldNumber = 39;
+  const ::std::string& swift_prefix() const;
+  void set_swift_prefix(const ::std::string& value);
+  void set_swift_prefix(const char* value);
+  void set_swift_prefix(const char* value, size_t size);
+  ::std::string* mutable_swift_prefix();
+  ::std::string* release_swift_prefix();
+  void set_allocated_swift_prefix(::std::string* swift_prefix);
+
   // repeated .google.protobuf.UninterpretedOption uninterpreted_option = 999;
   int uninterpreted_option_size() const;
   void clear_uninterpreted_option();
@@ -2278,6 +2290,8 @@ class LIBPROTOBUF_EXPORT FileOptions : public ::google::protobuf::Message /* @@p
   void clear_has_objc_class_prefix();
   void set_has_csharp_namespace();
   void clear_has_csharp_namespace();
+  void set_has_swift_prefix();
+  void clear_has_swift_prefix();
 
   ::google::protobuf::internal::ExtensionSet _extensions_;
 
@@ -2290,6 +2304,7 @@ class LIBPROTOBUF_EXPORT FileOptions : public ::google::protobuf::Message /* @@p
   ::google::protobuf::internal::ArenaStringPtr go_package_;
   ::google::protobuf::internal::ArenaStringPtr objc_class_prefix_;
   ::google::protobuf::internal::ArenaStringPtr csharp_namespace_;
+  ::google::protobuf::internal::ArenaStringPtr swift_prefix_;
   bool java_multiple_files_;
   bool java_generate_equals_and_hash_;
   bool java_string_check_utf8_;
@@ -6364,13 +6379,13 @@ inline void FileOptions::set_allocated_java_outer_classname(::std::string* java_
 
 // optional bool java_multiple_files = 10 [default = false];
 inline bool FileOptions::has_java_multiple_files() const {
-  return (_has_bits_[0] & 0x00000020u) != 0;
+  return (_has_bits_[0] & 0x00000040u) != 0;
 }
 inline void FileOptions::set_has_java_multiple_files() {
-  _has_bits_[0] |= 0x00000020u;
+  _has_bits_[0] |= 0x00000040u;
 }
 inline void FileOptions::clear_has_java_multiple_files() {
-  _has_bits_[0] &= ~0x00000020u;
+  _has_bits_[0] &= ~0x00000040u;
 }
 inline void FileOptions::clear_java_multiple_files() {
   java_multiple_files_ = false;
@@ -6388,13 +6403,13 @@ inline void FileOptions::set_java_multiple_files(bool value) {
 
 // optional bool java_generate_equals_and_hash = 20 [deprecated = true];
 inline bool FileOptions::has_java_generate_equals_and_hash() const {
-  return (_has_bits_[0] & 0x00000040u) != 0;
+  return (_has_bits_[0] & 0x00000080u) != 0;
 }
 inline void FileOptions::set_has_java_generate_equals_and_hash() {
-  _has_bits_[0] |= 0x00000040u;
+  _has_bits_[0] |= 0x00000080u;
 }
 inline void FileOptions::clear_has_java_generate_equals_and_hash() {
-  _has_bits_[0] &= ~0x00000040u;
+  _has_bits_[0] &= ~0x00000080u;
 }
 inline void FileOptions::clear_java_generate_equals_and_hash() {
   java_generate_equals_and_hash_ = false;
@@ -6412,13 +6427,13 @@ inline void FileOptions::set_java_generate_equals_and_hash(bool value) {
 
 // optional bool java_string_check_utf8 = 27 [default = false];
 inline bool FileOptions::has_java_string_check_utf8() const {
-  return (_has_bits_[0] & 0x00000080u) != 0;
+  return (_has_bits_[0] & 0x00000100u) != 0;
 }
 inline void FileOptions::set_has_java_string_check_utf8() {
-  _has_bits_[0] |= 0x00000080u;
+  _has_bits_[0] |= 0x00000100u;
 }
 inline void FileOptions::clear_has_java_string_check_utf8() {
-  _has_bits_[0] &= ~0x00000080u;
+  _has_bits_[0] &= ~0x00000100u;
 }
 inline void FileOptions::clear_java_string_check_utf8() {
   java_string_check_utf8_ = false;
@@ -6436,13 +6451,13 @@ inline void FileOptions::set_java_string_check_utf8(bool value) {
 
 // optional .google.protobuf.FileOptions.OptimizeMode optimize_for = 9 [default = SPEED];
 inline bool FileOptions::has_optimize_for() const {
-  return (_has_bits_[0] & 0x00002000u) != 0;
+  return (_has_bits_[0] & 0x00004000u) != 0;
 }
 inline void FileOptions::set_has_optimize_for() {
-  _has_bits_[0] |= 0x00002000u;
+  _has_bits_[0] |= 0x00004000u;
 }
 inline void FileOptions::clear_has_optimize_for() {
-  _has_bits_[0] &= ~0x00002000u;
+  _has_bits_[0] &= ~0x00004000u;
 }
 inline void FileOptions::clear_optimize_for() {
   optimize_for_ = 1;
@@ -6515,13 +6530,13 @@ inline void FileOptions::set_allocated_go_package(::std::string* go_package) {
 
 // optional bool cc_generic_services = 16 [default = false];
 inline bool FileOptions::has_cc_generic_services() const {
-  return (_has_bits_[0] & 0x00000100u) != 0;
+  return (_has_bits_[0] & 0x00000200u) != 0;
 }
 inline void FileOptions::set_has_cc_generic_services() {
-  _has_bits_[0] |= 0x00000100u;
+  _has_bits_[0] |= 0x00000200u;
 }
 inline void FileOptions::clear_has_cc_generic_services() {
-  _has_bits_[0] &= ~0x00000100u;
+  _has_bits_[0] &= ~0x00000200u;
 }
 inline void FileOptions::clear_cc_generic_services() {
   cc_generic_services_ = false;
@@ -6539,13 +6554,13 @@ inline void FileOptions::set_cc_generic_services(bool value) {
 
 // optional bool java_generic_services = 17 [default = false];
 inline bool FileOptions::has_java_generic_services() const {
-  return (_has_bits_[0] & 0x00000200u) != 0;
+  return (_has_bits_[0] & 0x00000400u) != 0;
 }
 inline void FileOptions::set_has_java_generic_services() {
-  _has_bits_[0] |= 0x00000200u;
+  _has_bits_[0] |= 0x00000400u;
 }
 inline void FileOptions::clear_has_java_generic_services() {
-  _has_bits_[0] &= ~0x00000200u;
+  _has_bits_[0] &= ~0x00000400u;
 }
 inline void FileOptions::clear_java_generic_services() {
   java_generic_services_ = false;
@@ -6563,13 +6578,13 @@ inline void FileOptions::set_java_generic_services(bool value) {
 
 // optional bool py_generic_services = 18 [default = false];
 inline bool FileOptions::has_py_generic_services() const {
-  return (_has_bits_[0] & 0x00000400u) != 0;
+  return (_has_bits_[0] & 0x00000800u) != 0;
 }
 inline void FileOptions::set_has_py_generic_services() {
-  _has_bits_[0] |= 0x00000400u;
+  _has_bits_[0] |= 0x00000800u;
 }
 inline void FileOptions::clear_has_py_generic_services() {
-  _has_bits_[0] &= ~0x00000400u;
+  _has_bits_[0] &= ~0x00000800u;
 }
 inline void FileOptions::clear_py_generic_services() {
   py_generic_services_ = false;
@@ -6587,13 +6602,13 @@ inline void FileOptions::set_py_generic_services(bool value) {
 
 // optional bool deprecated = 23 [default = false];
 inline bool FileOptions::has_deprecated() const {
-  return (_has_bits_[0] & 0x00000800u) != 0;
+  return (_has_bits_[0] & 0x00001000u) != 0;
 }
 inline void FileOptions::set_has_deprecated() {
-  _has_bits_[0] |= 0x00000800u;
+  _has_bits_[0] |= 0x00001000u;
 }
 inline void FileOptions::clear_has_deprecated() {
-  _has_bits_[0] &= ~0x00000800u;
+  _has_bits_[0] &= ~0x00001000u;
 }
 inline void FileOptions::clear_deprecated() {
   deprecated_ = false;
@@ -6611,13 +6626,13 @@ inline void FileOptions::set_deprecated(bool value) {
 
 // optional bool cc_enable_arenas = 31 [default = false];
 inline bool FileOptions::has_cc_enable_arenas() const {
-  return (_has_bits_[0] & 0x00001000u) != 0;
+  return (_has_bits_[0] & 0x00002000u) != 0;
 }
 inline void FileOptions::set_has_cc_enable_arenas() {
-  _has_bits_[0] |= 0x00001000u;
+  _has_bits_[0] |= 0x00002000u;
 }
 inline void FileOptions::clear_has_cc_enable_arenas() {
-  _has_bits_[0] &= ~0x00001000u;
+  _has_bits_[0] &= ~0x00002000u;
 }
 inline void FileOptions::clear_cc_enable_arenas() {
   cc_enable_arenas_ = false;
@@ -6741,6 +6756,60 @@ inline void FileOptions::set_allocated_csharp_namespace(::std::string* csharp_na
   // @@protoc_insertion_point(field_set_allocated:google.protobuf.FileOptions.csharp_namespace)
 }
 
+// optional string swift_prefix = 39;
+inline bool FileOptions::has_swift_prefix() const {
+  return (_has_bits_[0] & 0x00000020u) != 0;
+}
+inline void FileOptions::set_has_swift_prefix() {
+  _has_bits_[0] |= 0x00000020u;
+}
+inline void FileOptions::clear_has_swift_prefix() {
+  _has_bits_[0] &= ~0x00000020u;
+}
+inline void FileOptions::clear_swift_prefix() {
+  swift_prefix_.ClearToEmptyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+  clear_has_swift_prefix();
+}
+inline const ::std::string& FileOptions::swift_prefix() const {
+  // @@protoc_insertion_point(field_get:google.protobuf.FileOptions.swift_prefix)
+  return swift_prefix_.GetNoArena();
+}
+inline void FileOptions::set_swift_prefix(const ::std::string& value) {
+  set_has_swift_prefix();
+  swift_prefix_.SetNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), value);
+  // @@protoc_insertion_point(field_set:google.protobuf.FileOptions.swift_prefix)
+}
+inline void FileOptions::set_swift_prefix(const char* value) {
+  set_has_swift_prefix();
+  swift_prefix_.SetNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), ::std::string(value));
+  // @@protoc_insertion_point(field_set_char:google.protobuf.FileOptions.swift_prefix)
+}
+inline void FileOptions::set_swift_prefix(const char* value, size_t size) {
+  set_has_swift_prefix();
+  swift_prefix_.SetNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited(),
+      ::std::string(reinterpret_cast<const char*>(value), size));
+  // @@protoc_insertion_point(field_set_pointer:google.protobuf.FileOptions.swift_prefix)
+}
+inline ::std::string* FileOptions::mutable_swift_prefix() {
+  set_has_swift_prefix();
+  // @@protoc_insertion_point(field_mutable:google.protobuf.FileOptions.swift_prefix)
+  return swift_prefix_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+}
+inline ::std::string* FileOptions::release_swift_prefix() {
+  // @@protoc_insertion_point(field_release:google.protobuf.FileOptions.swift_prefix)
+  clear_has_swift_prefix();
+  return swift_prefix_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+}
+inline void FileOptions::set_allocated_swift_prefix(::std::string* swift_prefix) {
+  if (swift_prefix != NULL) {
+    set_has_swift_prefix();
+  } else {
+    clear_has_swift_prefix();
+  }
+  swift_prefix_.SetAllocatedNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), swift_prefix);
+  // @@protoc_insertion_point(field_set_allocated:google.protobuf.FileOptions.swift_prefix)
+}
+
 // repeated .google.protobuf.UninterpretedOption uninterpreted_option = 999;
 inline int FileOptions::uninterpreted_option_size() const {
   return uninterpreted_option_.size();
diff --git a/src/google/protobuf/descriptor.proto b/src/google/protobuf/descriptor.proto
index d9b9064b..eae31601 100644
--- a/src/google/protobuf/descriptor.proto
+++ b/src/google/protobuf/descriptor.proto
@@ -366,6 +366,12 @@ message FileOptions {
   // Namespace for generated classes; defaults to the package.
   optional string csharp_namespace = 37;
 
+  // By default Swift generators will take the proto package and CamelCase it
+  // replacing '.' with underscore and use that to prefix the types/symbols
+  // defined. When this options is provided, they will use this value instead
+  // to prefix the types/symbols defined.
+  optional string swift_prefix = 39;
+
   // The parser stores options it doesn't recognize here. See above.
   repeated UninterpretedOption uninterpreted_option = 999;