Down-integrate from internal branch

66 files changed, 3306 insertions, 1046 deletions

diff --git a/src/google/protobuf/compiler/command_line_interface.cc b/src/google/protobuf/compiler/command_line_interface.cc
index 1c76994b..8dac5f42 100644
--- a/src/google/protobuf/compiler/command_line_interface.cc
+++ b/src/google/protobuf/compiler/command_line_interface.cc
@@ -59,12 +59,13 @@
 #include <google/protobuf/descriptor.h>
 #include <google/protobuf/text_format.h>
 #include <google/protobuf/dynamic_message.h>
+#include <google/protobuf/io/coded_stream.h>
 #include <google/protobuf/io/zero_copy_stream_impl.h>
 #include <google/protobuf/io/printer.h>
 #include <google/protobuf/stubs/strutil.h>
 #include <google/protobuf/stubs/substitute.h>
 #include <google/protobuf/stubs/map-util.h>
-#include <google/protobuf/stubs/stl_util-inl.h>
+#include <google/protobuf/stubs/stl_util.h>
 
 
 namespace google {
@@ -145,7 +146,7 @@ void AddTrailingSlash(string* path) {
 bool VerifyDirectoryExists(const string& path) {
   if (path.empty()) return true;
 
-  if (access(path.c_str(), W_OK) == -1) {
+  if (access(path.c_str(), F_OK) == -1) {
     cerr << path << ": " << strerror(errno) << endl;
     return false;
   } else {
@@ -566,6 +567,7 @@ CommandLineInterface::CommandLineInterface()
   : mode_(MODE_COMPILE),
     error_format_(ERROR_FORMAT_GCC),
     imports_in_descriptor_set_(false),
+    source_info_in_descriptor_set_(false),
     disallow_services_(false),
     inputs_are_proto_path_relative_(false) {}
 CommandLineInterface::~CommandLineInterface() {}
@@ -574,9 +576,23 @@ void CommandLineInterface::RegisterGenerator(const string& flag_name,
                                              CodeGenerator* generator,
                                              const string& help_text) {
   GeneratorInfo info;
+  info.flag_name = flag_name;
   info.generator = generator;
   info.help_text = help_text;
-  generators_[flag_name] = info;
+  generators_by_flag_name_[flag_name] = info;
+}
+
+void CommandLineInterface::RegisterGenerator(const string& flag_name,
+                                             const string& option_flag_name,
+                                             CodeGenerator* generator,
+                                             const string& help_text) {
+  GeneratorInfo info;
+  info.flag_name = flag_name;
+  info.option_flag_name = option_flag_name;
+  info.generator = generator;
+  info.help_text = help_text;
+  generators_by_flag_name_[flag_name] = info;
+  generators_by_option_name_[option_flag_name] = info;
 }
 
 void CommandLineInterface::AllowPlugins(const string& exe_name_prefix) {
@@ -585,7 +601,14 @@ void CommandLineInterface::AllowPlugins(const string& exe_name_prefix) {
 
 int CommandLineInterface::Run(int argc, const char* const argv[]) {
   Clear();
-  if (!ParseArguments(argc, argv)) return 1;
+  switch (ParseArguments(argc, argv)) {
+    case PARSE_ARGUMENT_DONE_AND_EXIT:
+      return 0;
+    case PARSE_ARGUMENT_FAIL:
+      return 1;
+    case PARSE_ARGUMENT_DONE_AND_CONTINUE:
+      break;
+  }
 
   // Set up the source tree.
   DiskSourceTree source_tree;
@@ -713,6 +736,7 @@ void CommandLineInterface::Clear() {
 
   mode_ = MODE_COMPILE;
   imports_in_descriptor_set_ = false;
+  source_info_in_descriptor_set_ = false;
   disallow_services_ = false;
 }
 
@@ -755,7 +779,8 @@ bool CommandLineInterface::MakeInputsBeProtoPathRelative(
   return true;
 }
 
-bool CommandLineInterface::ParseArguments(int argc, const char* const argv[]) {
+CommandLineInterface::ParseArgumentStatus
+CommandLineInterface::ParseArguments(int argc, const char* const argv[]) {
   executable_name_ = argv[0];
 
   // Iterate through all arguments and parse them.
@@ -769,41 +794,50 @@ bool CommandLineInterface::ParseArguments(int argc, const char* const argv[]) {
         if (name == "--decode") {
           cerr << "To decode an unknown message, use --decode_raw." << endl;
         }
-        return false;
+        return PARSE_ARGUMENT_FAIL;
       } else {
         ++i;
         value = argv[i];
       }
     }
 
-    if (!InterpretArgument(name, value)) return false;
+    ParseArgumentStatus status = InterpretArgument(name, value);
+    if (status != PARSE_ARGUMENT_DONE_AND_CONTINUE)
+      return status;
   }
 
   // If no --proto_path was given, use the current working directory.
   if (proto_path_.empty()) {
-    proto_path_.push_back(make_pair<string, string>("", "."));
+    // Don't use make_pair as the old/default standard library on Solaris
+    // doesn't support it without explicit template parameters, which are
+    // incompatible with C++0x's make_pair.
+    proto_path_.push_back(pair<string, string>("", "."));
   }
 
   // Check some errror cases.
   bool decoding_raw = (mode_ == MODE_DECODE) && codec_type_.empty();
   if (decoding_raw && !input_files_.empty()) {
     cerr << "When using --decode_raw, no input files should be given." << endl;
-    return false;
+    return PARSE_ARGUMENT_FAIL;
   } else if (!decoding_raw && input_files_.empty()) {
     cerr << "Missing input file." << endl;
-    return false;
+    return PARSE_ARGUMENT_FAIL;
   }
   if (mode_ == MODE_COMPILE && output_directives_.empty() &&
       descriptor_set_name_.empty()) {
     cerr << "Missing output directives." << endl;
-    return false;
+    return PARSE_ARGUMENT_FAIL;
   }
   if (imports_in_descriptor_set_ && descriptor_set_name_.empty()) {
     cerr << "--include_imports only makes sense when combined with "
             "--descriptor_set_out." << endl;
   }
+  if (source_info_in_descriptor_set_ && descriptor_set_name_.empty()) {
+    cerr << "--include_source_info only makes sense when combined with "
+            "--descriptor_set_out." << endl;
+  }
 
-  return true;
+  return PARSE_ARGUMENT_DONE_AND_CONTINUE;
 }
 
 bool CommandLineInterface::ParseArgument(const char* arg,
@@ -853,6 +887,7 @@ bool CommandLineInterface::ParseArgument(const char* arg,
   if (*name == "-h" || *name == "--help" ||
       *name == "--disallow_services" ||
       *name == "--include_imports" ||
+      *name == "--include_source_info" ||
       *name == "--version" ||
       *name == "--decode_raw") {
     // HACK:  These are the only flags that don't take a value.
@@ -865,8 +900,9 @@ bool CommandLineInterface::ParseArgument(const char* arg,
   return true;
 }
 
-bool CommandLineInterface::InterpretArgument(const string& name,
-                                             const string& value) {
+CommandLineInterface::ParseArgumentStatus
+CommandLineInterface::InterpretArgument(const string& name,
+                                        const string& value) {
   if (name.empty()) {
     // Not a flag.  Just a filename.
     if (value.empty()) {
@@ -874,7 +910,7 @@ bool CommandLineInterface::InterpretArgument(const string& name,
               "arguments to " << executable_name_ << ".  This is actually "
               "sort of hard to do.  Congrats.  Unfortunately it is not valid "
               "input so the program is going to die now." << endl;
-      return false;
+      return PARSE_ARGUMENT_FAIL;
     }
 
     input_files_.push_back(value);
@@ -902,7 +938,7 @@ bool CommandLineInterface::InterpretArgument(const string& name,
       if (disk_path.empty()) {
         cerr << "--proto_path passed empty directory name.  (Use \".\" for "
                 "current directory.)" << endl;
-        return false;
+        return PARSE_ARGUMENT_FAIL;
       }
 
       // Make sure disk path exists, warn otherwise.
@@ -910,35 +946,45 @@ bool CommandLineInterface::InterpretArgument(const string& name,
         cerr << disk_path << ": warning: directory does not exist." << endl;
       }
 
-      proto_path_.push_back(make_pair<string, string>(virtual_path, disk_path));
+      // Don't use make_pair as the old/default standard library on Solaris
+      // doesn't support it without explicit template parameters, which are
+      // incompatible with C++0x's make_pair.
+      proto_path_.push_back(pair<string, string>(virtual_path, disk_path));
     }
 
   } else if (name == "-o" || name == "--descriptor_set_out") {
     if (!descriptor_set_name_.empty()) {
       cerr << name << " may only be passed once." << endl;
-      return false;
+      return PARSE_ARGUMENT_FAIL;
     }
     if (value.empty()) {
       cerr << name << " requires a non-empty value." << endl;
-      return false;
+      return PARSE_ARGUMENT_FAIL;
     }
     if (mode_ != MODE_COMPILE) {
       cerr << "Cannot use --encode or --decode and generate descriptors at the "
               "same time." << endl;
-      return false;
+      return PARSE_ARGUMENT_FAIL;
     }
     descriptor_set_name_ = value;
 
   } else if (name == "--include_imports") {
     if (imports_in_descriptor_set_) {
       cerr << name << " may only be passed once." << endl;
-      return false;
+      return PARSE_ARGUMENT_FAIL;
     }
     imports_in_descriptor_set_ = true;
 
+  } else if (name == "--include_source_info") {
+    if (source_info_in_descriptor_set_) {
+      cerr << name << " may only be passed once." << endl;
+      return PARSE_ARGUMENT_FAIL;
+    }
+    source_info_in_descriptor_set_ = true;
+
   } else if (name == "-h" || name == "--help") {
     PrintHelpText();
-    return false;  // Exit without running compiler.
+    return PARSE_ARGUMENT_DONE_AND_EXIT;  // Exit without running compiler.
 
   } else if (name == "--version") {
     if (!version_info_.empty()) {
@@ -947,7 +993,7 @@ bool CommandLineInterface::InterpretArgument(const string& name,
     cout << "libprotoc "
          << protobuf::internal::VersionString(GOOGLE_PROTOBUF_VERSION)
          << endl;
-    return false;  // Exit without running compiler.
+    return PARSE_ARGUMENT_DONE_AND_EXIT;  // Exit without running compiler.
 
   } else if (name == "--disallow_services") {
     disallow_services_ = true;
@@ -956,12 +1002,12 @@ bool CommandLineInterface::InterpretArgument(const string& name,
              name == "--decode_raw") {
     if (mode_ != MODE_COMPILE) {
       cerr << "Only one of --encode and --decode can be specified." << endl;
-      return false;
+      return PARSE_ARGUMENT_FAIL;
     }
     if (!output_directives_.empty() || !descriptor_set_name_.empty()) {
       cerr << "Cannot use " << name
            << " and generate code or descriptors at the same time." << endl;
-      return false;
+      return PARSE_ARGUMENT_FAIL;
     }
 
     mode_ = (name == "--encode") ? MODE_ENCODE : MODE_DECODE;
@@ -971,10 +1017,10 @@ bool CommandLineInterface::InterpretArgument(const string& name,
       if (name == "--decode") {
         cerr << "To decode an unknown message, use --decode_raw." << endl;
       }
-      return false;
+      return PARSE_ARGUMENT_FAIL;
     } else if (!value.empty() && name == "--decode_raw") {
       cerr << "--decode_raw does not take a parameter." << endl;
-      return false;
+      return PARSE_ARGUMENT_FAIL;
     }
 
     codec_type_ = value;
@@ -986,16 +1032,16 @@ bool CommandLineInterface::InterpretArgument(const string& name,
       error_format_ = ERROR_FORMAT_MSVS;
     } else {
       cerr << "Unknown error format: " << value << endl;
-      return false;
+      return PARSE_ARGUMENT_FAIL;
     }
 
   } else if (name == "--plugin") {
     if (plugin_prefix_.empty()) {
       cerr << "This compiler does not support plugins." << endl;
-      return false;
+      return PARSE_ARGUMENT_FAIL;
     }
 
-    string name;
+    string plugin_name;
     string path;
 
     string::size_type equals_pos = value.find_first_of('=');
@@ -1003,57 +1049,68 @@ bool CommandLineInterface::InterpretArgument(const string& name,
       // Use the basename of the file.
       string::size_type slash_pos = value.find_last_of('/');
       if (slash_pos == string::npos) {
-        name = value;
+        plugin_name = value;
       } else {
-        name = value.substr(slash_pos + 1);
+        plugin_name = value.substr(slash_pos + 1);
       }
       path = value;
     } else {
-      name = value.substr(0, equals_pos);
+      plugin_name = value.substr(0, equals_pos);
       path = value.substr(equals_pos + 1);
     }
 
-    plugins_[name] = path;
+    plugins_[plugin_name] = path;
 
   } else {
     // Some other flag.  Look it up in the generators list.
-    const GeneratorInfo* generator_info = FindOrNull(generators_, name);
+    const GeneratorInfo* generator_info =
+        FindOrNull(generators_by_flag_name_, name);
     if (generator_info == NULL &&
         (plugin_prefix_.empty() || !HasSuffixString(name, "_out"))) {
-      cerr << "Unknown flag: " << name << endl;
-      return false;
-    }
+      // Check if it's a generator option flag.
+      generator_info = FindOrNull(generators_by_option_name_, name);
+      if (generator_info == NULL) {
+        cerr << "Unknown flag: " << name << endl;
+        return PARSE_ARGUMENT_FAIL;
+      } else {
+        string* parameters = &generator_parameters_[generator_info->flag_name];
+        if (!parameters->empty()) {
+          parameters->append(",");
+        }
+        parameters->append(value);
+      }
+    } else {
+      // It's an output flag.  Add it to the output directives.
+      if (mode_ != MODE_COMPILE) {
+        cerr << "Cannot use --encode or --decode and generate code at the "
+                "same time." << endl;
+        return PARSE_ARGUMENT_FAIL;
+      }
 
-    // It's an output flag.  Add it to the output directives.
-    if (mode_ != MODE_COMPILE) {
-      cerr << "Cannot use --encode or --decode and generate code at the "
-              "same time." << endl;
-      return false;
-    }
+      OutputDirective directive;
+      directive.name = name;
+      if (generator_info == NULL) {
+        directive.generator = NULL;
+      } else {
+        directive.generator = generator_info->generator;
+      }
 
-    OutputDirective directive;
-    directive.name = name;
-    if (generator_info == NULL) {
-      directive.generator = NULL;
-    } else {
-      directive.generator = generator_info->generator;
-    }
+      // Split value at ':' to separate the generator parameter from the
+      // filename.  However, avoid doing this if the colon is part of a valid
+      // Windows-style absolute path.
+      string::size_type colon_pos = value.find_first_of(':');
+      if (colon_pos == string::npos || IsWindowsAbsolutePath(value)) {
+        directive.output_location = value;
+      } else {
+        directive.parameter = value.substr(0, colon_pos);
+        directive.output_location = value.substr(colon_pos + 1);
+      }
 
-    // Split value at ':' to separate the generator parameter from the
-    // filename.  However, avoid doing this if the colon is part of a valid
-    // Windows-style absolute path.
-    string::size_type colon_pos = value.find_first_of(':');
-    if (colon_pos == string::npos || IsWindowsAbsolutePath(value)) {
-      directive.output_location = value;
-    } else {
-      directive.parameter = value.substr(0, colon_pos);
-      directive.output_location = value.substr(colon_pos + 1);
+      output_directives_.push_back(directive);
     }
-
-    output_directives_.push_back(directive);
   }
 
-  return true;
+  return PARSE_ARGUMENT_DONE_AND_CONTINUE;
 }
 
 void CommandLineInterface::PrintHelpText() {
@@ -1086,6 +1143,12 @@ void CommandLineInterface::PrintHelpText() {
 "  --include_imports           When using --descriptor_set_out, also include\n"
 "                              all dependencies of the input files in the\n"
 "                              set, so that the set is self-contained.\n"
+"  --include_source_info       When using --descriptor_set_out, do not strip\n"
+"                              SourceCodeInfo from the FileDescriptorProto.\n"
+"                              This results in vastly larger descriptors that\n"
+"                              include information about the original\n"
+"                              location of each decl in the source file as\n"
+"                              well as surrounding comments.\n"
 "  --error_format=FORMAT       Set the format in which to print errors.\n"
 "                              FORMAT may be 'gcc' (the default) or 'msvs'\n"
 "                              (Microsoft Visual Studio format)." << endl;
@@ -1101,8 +1164,8 @@ void CommandLineInterface::PrintHelpText() {
 "                              the executable's own name differs." << endl;
   }
 
-  for (GeneratorMap::iterator iter = generators_.begin();
-       iter != generators_.end(); ++iter) {
+  for (GeneratorMap::iterator iter = generators_by_flag_name_.begin();
+       iter != generators_by_flag_name_.end(); ++iter) {
     // FIXME(kenton):  If the text is long enough it will wrap, which is ugly,
     //   but fixing this nicely (e.g. splitting on spaces) is probably more
     //   trouble than it's worth.
@@ -1136,10 +1199,16 @@ bool CommandLineInterface::GenerateOutput(
     }
   } else {
     // Regular generator.
+    string parameters = output_directive.parameter;
+    if (!generator_parameters_[output_directive.name].empty()) {
+      if (!parameters.empty()) {
+        parameters.append(",");
+      }
+      parameters.append(generator_parameters_[output_directive.name]);
+    }
     for (int i = 0; i < parsed_files.size(); i++) {
-      if (!output_directive.generator->Generate(
-          parsed_files[i], output_directive.parameter,
-          generator_context, &error)) {
+      if (!output_directive.generator->Generate(parsed_files[i], parameters,
+                                                generator_context, &error)) {
         // Generator returned an error.
         cerr << output_directive.name << ": " << parsed_files[i]->name() << ": "
              << error << endl;
@@ -1168,8 +1237,9 @@ bool CommandLineInterface::GeneratePluginOutput(
   set<const FileDescriptor*> already_seen;
   for (int i = 0; i < parsed_files.size(); i++) {
     request.add_file_to_generate(parsed_files[i]->name());
-    GetTransitiveDependencies(parsed_files[i], &already_seen,
-                              request.mutable_proto_file());
+    GetTransitiveDependencies(parsed_files[i],
+                              true,  // Include source code info.
+                              &already_seen, request.mutable_proto_file());
   }
 
   // Invoke the plugin.
@@ -1299,12 +1369,17 @@ bool CommandLineInterface::WriteDescriptorSet(
   if (imports_in_descriptor_set_) {
     set<const FileDescriptor*> already_seen;
     for (int i = 0; i < parsed_files.size(); i++) {
-      GetTransitiveDependencies(
-          parsed_files[i], &already_seen, file_set.mutable_file());
+      GetTransitiveDependencies(parsed_files[i],
+                                source_info_in_descriptor_set_,
+                                &already_seen, file_set.mutable_file());
     }
   } else {
     for (int i = 0; i < parsed_files.size(); i++) {
-      parsed_files[i]->CopyTo(file_set.add_file());
+      FileDescriptorProto* file_proto = file_set.add_file();
+      parsed_files[i]->CopyTo(file_proto);
+      if (source_info_in_descriptor_set_) {
+        parsed_files[i]->CopySourceCodeInfoTo(file_proto);
+      }
     }
   }
 
@@ -1334,7 +1409,7 @@ bool CommandLineInterface::WriteDescriptorSet(
 }
 
 void CommandLineInterface::GetTransitiveDependencies(
-    const FileDescriptor* file,
+    const FileDescriptor* file, bool include_source_code_info,
     set<const FileDescriptor*>* already_seen,
     RepeatedPtrField<FileDescriptorProto>* output) {
   if (!already_seen->insert(file).second) {
@@ -1344,11 +1419,16 @@ void CommandLineInterface::GetTransitiveDependencies(
 
   // Add all dependencies.
   for (int i = 0; i < file->dependency_count(); i++) {
-    GetTransitiveDependencies(file->dependency(i), already_seen, output);
+    GetTransitiveDependencies(file->dependency(i), include_source_code_info,
+                              already_seen, output);
   }
 
   // Add this file.
-  file->CopyTo(output->Add());
+  FileDescriptorProto* new_descriptor = output->Add();
+  file->CopyTo(new_descriptor);
+  if (include_source_code_info) {
+    file->CopySourceCodeInfoTo(new_descriptor);
+  }
 }
 
 
diff --git a/src/google/protobuf/compiler/command_line_interface.h b/src/google/protobuf/compiler/command_line_interface.h
index 0b507d80..86ea9bde 100644
--- a/src/google/protobuf/compiler/command_line_interface.h
+++ b/src/google/protobuf/compiler/command_line_interface.h
@@ -112,6 +112,19 @@ class LIBPROTOC_EXPORT CommandLineInterface {
                          CodeGenerator* generator,
                          const string& help_text);
 
+  // Register a code generator for a language.
+  // Besides flag_name you can specify another option_flag_name that could be
+  // used to pass extra parameters to the registered code generator.
+  // Suppose you have registered a generator by calling:
+  //   command_line_interface.RegisterGenerator("--foo_out", "--foo_opt", ...)
+  // Then you could invoke the compiler with a command like:
+  //   protoc --foo_out=enable_bar:outdir --foo_opt=enable_baz
+  // This will pass "enable_bar,enable_baz" as the parameter to the generator.
+  void RegisterGenerator(const string& flag_name,
+                         const string& option_flag_name,
+                         CodeGenerator* generator,
+                         const string& help_text);
+
   // Enables "plugins".  In this mode, if a command-line flag ends with "_out"
   // but does not match any registered generator, the compiler will attempt to
   // find a "plugin" to implement the generator.  Plugins are just executables.
@@ -186,8 +199,15 @@ class LIBPROTOC_EXPORT CommandLineInterface {
   bool MakeInputsBeProtoPathRelative(
     DiskSourceTree* source_tree);
 
+  // Return status for ParseArguments() and InterpretArgument().
+  enum ParseArgumentStatus {
+    PARSE_ARGUMENT_DONE_AND_CONTINUE,
+    PARSE_ARGUMENT_DONE_AND_EXIT,
+    PARSE_ARGUMENT_FAIL
+  };
+
   // Parse all command-line arguments.
-  bool ParseArguments(int argc, const char* const argv[]);
+  ParseArgumentStatus ParseArguments(int argc, const char* const argv[]);
 
   // Parses a command-line argument into a name/value pair.  Returns
   // true if the next argument in the argv should be used as the value,
@@ -203,7 +223,8 @@ class LIBPROTOC_EXPORT CommandLineInterface {
   bool ParseArgument(const char* arg, string* name, string* value);
 
   // Interprets arguments parsed with ParseArgument.
-  bool InterpretArgument(const string& name, const string& value);
+  ParseArgumentStatus InterpretArgument(const string& name,
+                                        const string& value);
 
   // Print the --help text to stderr.
   void PrintHelpText();
@@ -230,9 +251,11 @@ class LIBPROTOC_EXPORT CommandLineInterface {
   // protos will be ordered such that every file is listed before any file that
   // depends on it, so that you can call DescriptorPool::BuildFile() on them
   // in order.  Any files in *already_seen will not be added, and each file
-  // added will be inserted into *already_seen.
+  // added will be inserted into *already_seen.  If include_source_code_info is
+  // true then include the source code information in the FileDescriptorProtos.
   static void GetTransitiveDependencies(
       const FileDescriptor* file,
+      bool include_source_code_info,
       set<const FileDescriptor*>* already_seen,
       RepeatedPtrField<FileDescriptorProto>* output);
 
@@ -244,13 +267,21 @@ class LIBPROTOC_EXPORT CommandLineInterface {
   // Version info set with SetVersionInfo().
   string version_info_;
 
-  // Map from flag names to registered generators.
+  // Registered generators.
   struct GeneratorInfo {
+    string flag_name;
+    string option_flag_name;
     CodeGenerator* generator;
     string help_text;
   };
   typedef map<string, GeneratorInfo> GeneratorMap;
-  GeneratorMap generators_;
+  GeneratorMap generators_by_flag_name_;
+  GeneratorMap generators_by_option_name_;
+  // A map from generator names to the parameters specified using the option
+  // flag. For example, if the user invokes the compiler with:
+  //   protoc --foo_out=outputdir --foo_opt=enable_bar ...
+  // Then there will be an entry ("--foo_out", "enable_bar") in this map.
+  map<string, string> generator_parameters_;
 
   // See AllowPlugins().  If this is empty, plugins aren't allowed.
   string plugin_prefix_;
@@ -302,6 +333,10 @@ class LIBPROTOC_EXPORT CommandLineInterface {
   // the .proto files listed on the command-line are added.
   bool imports_in_descriptor_set_;
 
+  // True if --include_source_info was given, meaning that we should not strip
+  // SourceCodeInfo from the DescriptorSet.
+  bool source_info_in_descriptor_set_;
+
   // Was the --disallow_services flag used?
   bool disallow_services_;
 
diff --git a/src/google/protobuf/compiler/command_line_interface_unittest.cc b/src/google/protobuf/compiler/command_line_interface_unittest.cc
index d5b3a1dc..16559923 100644
--- a/src/google/protobuf/compiler/command_line_interface_unittest.cc
+++ b/src/google/protobuf/compiler/command_line_interface_unittest.cc
@@ -122,6 +122,10 @@ class CommandLineInterfaceTest : public testing::Test {
   // substring.
   void ExpectErrorSubstring(const string& expected_substring);
 
+  // Like ExpectErrorSubstring, but checks that Run() returned zero.
+  void ExpectErrorSubstringWithZeroReturnCode(
+      const string& expected_substring);
+
   // Returns true if ExpectErrorSubstring(expected_substring) would pass, but
   // does not fail otherwise.
   bool HasAlternateErrorSubstring(const string& expected_substring);
@@ -225,7 +229,7 @@ void CommandLineInterfaceTest::SetUp() {
   // Register generators.
   CodeGenerator* generator = new MockCodeGenerator("test_generator");
   mock_generators_to_delete_.push_back(generator);
-  cli_.RegisterGenerator("--test_out", generator, "Test output.");
+  cli_.RegisterGenerator("--test_out", "--test_opt", generator, "Test output.");
   cli_.RegisterGenerator("-t", generator, "Test output.");
 
   generator = new MockCodeGenerator("alt_generator");
@@ -345,6 +349,12 @@ void CommandLineInterfaceTest::ExpectErrorSubstring(
   EXPECT_PRED_FORMAT2(testing::IsSubstring, expected_substring, error_text_);
 }
 
+void CommandLineInterfaceTest::ExpectErrorSubstringWithZeroReturnCode(
+    const string& expected_substring) {
+  EXPECT_EQ(0, return_code_);
+  EXPECT_PRED_FORMAT2(testing::IsSubstring, expected_substring, error_text_);
+}
+
 bool CommandLineInterfaceTest::HasAlternateErrorSubstring(
     const string& expected_substring) {
   EXPECT_NE(0, return_code_);
@@ -544,6 +554,32 @@ TEST_F(CommandLineInterfaceTest, GeneratorParameters) {
   ExpectGenerated("test_plugin", "TestPluginParameter", "foo.proto", "Foo");
 }
 
+TEST_F(CommandLineInterfaceTest, ExtraGeneratorParameters) {
+  // Test that generator parameters specified with the option flag are
+  // correctly passed to the code generator.
+
+  CreateTempFile("foo.proto",
+    "syntax = \"proto2\";\n"
+    "message Foo {}\n");
+  // Create the "a" and "b" sub-directories.
+  CreateTempDir("a");
+  CreateTempDir("b");
+
+  Run("protocol_compiler "
+      "--test_opt=foo1 "
+      "--test_out=bar:$tmpdir/a "
+      "--test_opt=foo2 "
+      "--test_out=baz:$tmpdir/b "
+      "--test_opt=foo3 "
+      "--proto_path=$tmpdir foo.proto");
+
+  ExpectNoErrors();
+  ExpectGenerated(
+      "test_generator", "bar,foo1,foo2,foo3", "foo.proto", "Foo", "a");
+  ExpectGenerated(
+      "test_generator", "baz,foo1,foo2,foo3", "foo.proto", "Foo", "b");
+}
+
 TEST_F(CommandLineInterfaceTest, Insert) {
   // Test running a generator that inserts code into another's output.
 
@@ -779,6 +815,33 @@ TEST_F(CommandLineInterfaceTest, WriteDescriptorSet) {
   if (HasFatalFailure()) return;
   ASSERT_EQ(1, descriptor_set.file_size());
   EXPECT_EQ("bar.proto", descriptor_set.file(0).name());
+  // Descriptor set should not have source code info.
+  EXPECT_FALSE(descriptor_set.file(0).has_source_code_info());
+}
+
+TEST_F(CommandLineInterfaceTest, WriteDescriptorSetWithSourceInfo) {
+  CreateTempFile("foo.proto",
+    "syntax = \"proto2\";\n"
+    "message Foo {}\n");
+  CreateTempFile("bar.proto",
+    "syntax = \"proto2\";\n"
+    "import \"foo.proto\";\n"
+    "message Bar {\n"
+    "  optional Foo foo = 1;\n"
+    "}\n");
+
+  Run("protocol_compiler --descriptor_set_out=$tmpdir/descriptor_set "
+      "--include_source_info --proto_path=$tmpdir bar.proto");
+
+  ExpectNoErrors();
+
+  FileDescriptorSet descriptor_set;
+  ReadDescriptorSet("descriptor_set", &descriptor_set);
+  if (HasFatalFailure()) return;
+  ASSERT_EQ(1, descriptor_set.file_size());
+  EXPECT_EQ("bar.proto", descriptor_set.file(0).name());
+  // Source code info included.
+  EXPECT_TRUE(descriptor_set.file(0).has_source_code_info());
 }
 
 TEST_F(CommandLineInterfaceTest, WriteTransitiveDescriptorSet) {
@@ -807,6 +870,40 @@ TEST_F(CommandLineInterfaceTest, WriteTransitiveDescriptorSet) {
   }
   EXPECT_EQ("foo.proto", descriptor_set.file(0).name());
   EXPECT_EQ("bar.proto", descriptor_set.file(1).name());
+  // Descriptor set should not have source code info.
+  EXPECT_FALSE(descriptor_set.file(0).has_source_code_info());
+  EXPECT_FALSE(descriptor_set.file(1).has_source_code_info());
+}
+
+TEST_F(CommandLineInterfaceTest, WriteTransitiveDescriptorSetWithSourceInfo) {
+  CreateTempFile("foo.proto",
+    "syntax = \"proto2\";\n"
+    "message Foo {}\n");
+  CreateTempFile("bar.proto",
+    "syntax = \"proto2\";\n"
+    "import \"foo.proto\";\n"
+    "message Bar {\n"
+    "  optional Foo foo = 1;\n"
+    "}\n");
+
+  Run("protocol_compiler --descriptor_set_out=$tmpdir/descriptor_set "
+      "--include_imports --include_source_info --proto_path=$tmpdir bar.proto");
+
+  ExpectNoErrors();
+
+  FileDescriptorSet descriptor_set;
+  ReadDescriptorSet("descriptor_set", &descriptor_set);
+  if (HasFatalFailure()) return;
+  ASSERT_EQ(2, descriptor_set.file_size());
+  if (descriptor_set.file(0).name() == "bar.proto") {
+    std::swap(descriptor_set.mutable_file()->mutable_data()[0],
+              descriptor_set.mutable_file()->mutable_data()[1]);
+  }
+  EXPECT_EQ("foo.proto", descriptor_set.file(0).name());
+  EXPECT_EQ("bar.proto", descriptor_set.file(1).name());
+  // Source code info included.
+  EXPECT_TRUE(descriptor_set.file(0).has_source_code_info());
+  EXPECT_TRUE(descriptor_set.file(1).has_source_code_info());
 }
 
 // -------------------------------------------------------------------
@@ -1129,6 +1226,17 @@ TEST_F(CommandLineInterfaceTest, GeneratorPluginCrash) {
 #endif
 }
 
+TEST_F(CommandLineInterfaceTest, PluginReceivesSourceCodeInfo) {
+  CreateTempFile("foo.proto",
+    "syntax = \"proto2\";\n"
+    "message MockCodeGenerator_HasSourceCodeInfo {}\n");
+
+  Run("protocol_compiler --plug_out=$tmpdir --proto_path=$tmpdir foo.proto");
+
+  ExpectErrorSubstring(
+      "Saw message type MockCodeGenerator_HasSourceCodeInfo: 1.");
+}
+
 TEST_F(CommandLineInterfaceTest, GeneratorPluginNotFound) {
   // Test what happens if the plugin isn't found.
 
@@ -1171,11 +1279,11 @@ TEST_F(CommandLineInterfaceTest, GeneratorPluginNotAllowed) {
 TEST_F(CommandLineInterfaceTest, HelpText) {
   Run("test_exec_name --help");
 
-  ExpectErrorSubstring("Usage: test_exec_name ");
-  ExpectErrorSubstring("--test_out=OUT_DIR");
-  ExpectErrorSubstring("Test output.");
-  ExpectErrorSubstring("--alt_out=OUT_DIR");
-  ExpectErrorSubstring("Alt output.");
+  ExpectErrorSubstringWithZeroReturnCode("Usage: test_exec_name ");
+  ExpectErrorSubstringWithZeroReturnCode("--test_out=OUT_DIR");
+  ExpectErrorSubstringWithZeroReturnCode("Test output.");
+  ExpectErrorSubstringWithZeroReturnCode("--alt_out=OUT_DIR");
+  ExpectErrorSubstringWithZeroReturnCode("Alt output.");
 }
 
 TEST_F(CommandLineInterfaceTest, GccFormatErrors) {
diff --git a/src/google/protobuf/compiler/cpp/cpp_bootstrap_unittest.cc b/src/google/protobuf/compiler/cpp/cpp_bootstrap_unittest.cc
index bcfa5020..b7c1766b 100644
--- a/src/google/protobuf/compiler/cpp/cpp_bootstrap_unittest.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_bootstrap_unittest.cc
@@ -48,8 +48,8 @@
 #include <google/protobuf/compiler/importer.h>
 #include <google/protobuf/descriptor.h>
 #include <google/protobuf/io/zero_copy_stream_impl.h>
-#include <google/protobuf/stubs/stl_util-inl.h>
 #include <google/protobuf/stubs/map-util.h>
+#include <google/protobuf/stubs/stl_util.h>
 #include <google/protobuf/stubs/strutil.h>
 #include <google/protobuf/stubs/substitute.h>
 
diff --git a/src/google/protobuf/compiler/cpp/cpp_enum.cc b/src/google/protobuf/compiler/cpp/cpp_enum.cc
index 76d2b798..67c12d7a 100644
--- a/src/google/protobuf/compiler/cpp/cpp_enum.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_enum.cc
@@ -46,10 +46,10 @@ namespace compiler {
 namespace cpp {
 
 EnumGenerator::EnumGenerator(const EnumDescriptor* descriptor,
-                             const string& dllexport_decl)
+                             const Options& options)
   : descriptor_(descriptor),
     classname_(ClassName(descriptor, false)),
-    dllexport_decl_(dllexport_decl) {
+    options_(options) {
 }
 
 EnumGenerator::~EnumGenerator() {}
@@ -88,10 +88,10 @@ void EnumGenerator::GenerateDefinition(io::Printer* printer) {
   vars["min_name"] = min_value->name();
   vars["max_name"] = max_value->name();
 
-  if (dllexport_decl_.empty()) {
+  if (options_.dllexport_decl.empty()) {
     vars["dllexport"] = "";
   } else {
-    vars["dllexport"] = dllexport_decl_ + " ";
+    vars["dllexport"] = options_.dllexport_decl + " ";
   }
 
   printer->Print(vars,
diff --git a/src/google/protobuf/compiler/cpp/cpp_enum.h b/src/google/protobuf/compiler/cpp/cpp_enum.h
index 58f7721e..2e85a0bd 100644
--- a/src/google/protobuf/compiler/cpp/cpp_enum.h
+++ b/src/google/protobuf/compiler/cpp/cpp_enum.h
@@ -36,8 +36,10 @@
 #define GOOGLE_PROTOBUF_COMPILER_CPP_ENUM_H__
 
 #include <string>
+#include <google/protobuf/compiler/cpp/cpp_options.h>
 #include <google/protobuf/descriptor.h>
 
+
 namespace google {
 namespace protobuf {
   namespace io {
@@ -53,7 +55,7 @@ class EnumGenerator {
  public:
   // See generator.cc for the meaning of dllexport_decl.
   explicit EnumGenerator(const EnumDescriptor* descriptor,
-                         const string& dllexport_decl);
+                         const Options& options);
   ~EnumGenerator();
 
   // Header stuff.
@@ -86,7 +88,7 @@ class EnumGenerator {
  private:
   const EnumDescriptor* descriptor_;
   string classname_;
-  string dllexport_decl_;
+  Options options_;
 
   GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(EnumGenerator);
 };
diff --git a/src/google/protobuf/compiler/cpp/cpp_enum_field.cc b/src/google/protobuf/compiler/cpp/cpp_enum_field.cc
index a369f417..6e1620d4 100644
--- a/src/google/protobuf/compiler/cpp/cpp_enum_field.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_enum_field.cc
@@ -46,8 +46,9 @@ namespace cpp {
 namespace {
 
 void SetEnumVariables(const FieldDescriptor* descriptor,
-                      map<string, string>* variables) {
-  SetCommonFieldVariables(descriptor, variables);
+                      map<string, string>* variables,
+                      const Options& options) {
+  SetCommonFieldVariables(descriptor, variables, options);
   const EnumValueDescriptor* default_value = descriptor->default_value_enum();
   (*variables)["type"] = ClassName(descriptor->enum_type(), true);
   (*variables)["default"] = SimpleItoa(default_value->number());
@@ -58,9 +59,10 @@ void SetEnumVariables(const FieldDescriptor* descriptor,
 // ===================================================================
 
 EnumFieldGenerator::
-EnumFieldGenerator(const FieldDescriptor* descriptor)
+EnumFieldGenerator(const FieldDescriptor* descriptor,
+                   const Options& options)
   : descriptor_(descriptor) {
-  SetEnumVariables(descriptor, &variables_);
+  SetEnumVariables(descriptor, &variables_, options);
 }
 
 EnumFieldGenerator::~EnumFieldGenerator() {}
@@ -84,7 +86,7 @@ GenerateInlineAccessorDefinitions(io::Printer* printer) const {
     "  return static_cast< $type$ >($name$_);\n"
     "}\n"
     "inline void $classname$::set_$name$($type$ value) {\n"
-    "  GOOGLE_DCHECK($type$_IsValid(value));\n"
+    "  assert($type$_IsValid(value));\n"
     "  set_has_$name$();\n"
     "  $name$_ = value;\n"
     "}\n");
@@ -152,9 +154,10 @@ GenerateByteSize(io::Printer* printer) const {
 // ===================================================================
 
 RepeatedEnumFieldGenerator::
-RepeatedEnumFieldGenerator(const FieldDescriptor* descriptor)
+RepeatedEnumFieldGenerator(const FieldDescriptor* descriptor,
+                           const Options& options)
   : descriptor_(descriptor) {
-  SetEnumVariables(descriptor, &variables_);
+  SetEnumVariables(descriptor, &variables_, options);
 }
 
 RepeatedEnumFieldGenerator::~RepeatedEnumFieldGenerator() {}
@@ -187,11 +190,11 @@ GenerateInlineAccessorDefinitions(io::Printer* printer) const {
     "  return static_cast< $type$ >($name$_.Get(index));\n"
     "}\n"
     "inline void $classname$::set_$name$(int index, $type$ value) {\n"
-    "  GOOGLE_DCHECK($type$_IsValid(value));\n"
+    "  assert($type$_IsValid(value));\n"
     "  $name$_.Set(index, value);\n"
     "}\n"
     "inline void $classname$::add_$name$($type$ value) {\n"
-    "  GOOGLE_DCHECK($type$_IsValid(value));\n"
+    "  assert($type$_IsValid(value));\n"
     "  $name$_.Add(value);\n"
     "}\n");
   printer->Print(variables_,
@@ -345,7 +348,9 @@ GenerateByteSize(io::Printer* printer) const {
       "  total_size += $tag_size$ +\n"
       "    ::google::protobuf::internal::WireFormatLite::Int32Size(data_size);\n"
       "}\n"
+      "GOOGLE_SAFE_CONCURRENT_WRITES_BEGIN();\n"
       "_$name$_cached_byte_size_ = data_size;\n"
+      "GOOGLE_SAFE_CONCURRENT_WRITES_END();\n"
       "total_size += data_size;\n");
   } else {
     printer->Print(variables_,
diff --git a/src/google/protobuf/compiler/cpp/cpp_enum_field.h b/src/google/protobuf/compiler/cpp/cpp_enum_field.h
index 0793430c..65770083 100644
--- a/src/google/protobuf/compiler/cpp/cpp_enum_field.h
+++ b/src/google/protobuf/compiler/cpp/cpp_enum_field.h
@@ -46,7 +46,8 @@ namespace cpp {
 
 class EnumFieldGenerator : public FieldGenerator {
  public:
-  explicit EnumFieldGenerator(const FieldDescriptor* descriptor);
+  explicit EnumFieldGenerator(const FieldDescriptor* descriptor,
+                              const Options& options);
   ~EnumFieldGenerator();
 
   // implements FieldGenerator ---------------------------------------
@@ -71,7 +72,8 @@ class EnumFieldGenerator : public FieldGenerator {
 
 class RepeatedEnumFieldGenerator : public FieldGenerator {
  public:
-  explicit RepeatedEnumFieldGenerator(const FieldDescriptor* descriptor);
+  explicit RepeatedEnumFieldGenerator(const FieldDescriptor* descriptor,
+                                      const Options& options);
   ~RepeatedEnumFieldGenerator();
 
   // implements FieldGenerator ---------------------------------------
diff --git a/src/google/protobuf/compiler/cpp/cpp_extension.cc b/src/google/protobuf/compiler/cpp/cpp_extension.cc
index 658a7077..ef56b5e5 100644
--- a/src/google/protobuf/compiler/cpp/cpp_extension.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_extension.cc
@@ -57,9 +57,9 @@ string ExtendeeClassName(const FieldDescriptor* descriptor) {
 }  // anonymous namespace
 
 ExtensionGenerator::ExtensionGenerator(const FieldDescriptor* descriptor,
-                                       const string& dllexport_decl)
+                                       const Options& options)
   : descriptor_(descriptor),
-    dllexport_decl_(dllexport_decl) {
+    options_(options) {
   // Construct type_traits_.
   if (descriptor_->is_repeated()) {
     type_traits_ = "Repeated";
@@ -106,8 +106,8 @@ void ExtensionGenerator::GenerateDeclaration(io::Printer* printer) {
   // export/import specifier.
   if (descriptor_->extension_scope() == NULL) {
     vars["qualifier"] = "extern";
-    if (!dllexport_decl_.empty()) {
-      vars["qualifier"] = dllexport_decl_ + " " + vars["qualifier"];
+    if (!options_.dllexport_decl.empty()) {
+      vars["qualifier"] = options_.dllexport_decl + " " + vars["qualifier"];
     }
   } else {
     vars["qualifier"] = "static";
diff --git a/src/google/protobuf/compiler/cpp/cpp_extension.h b/src/google/protobuf/compiler/cpp/cpp_extension.h
index 3068b091..50ad035b 100644
--- a/src/google/protobuf/compiler/cpp/cpp_extension.h
+++ b/src/google/protobuf/compiler/cpp/cpp_extension.h
@@ -37,6 +37,7 @@
 
 #include <string>
 #include <google/protobuf/stubs/common.h>
+#include <google/protobuf/compiler/cpp/cpp_options.h>
 
 namespace google {
 namespace protobuf {
@@ -56,8 +57,8 @@ namespace cpp {
 class ExtensionGenerator {
  public:
   // See generator.cc for the meaning of dllexport_decl.
-  explicit ExtensionGenerator(const FieldDescriptor* descriptor,
-                              const string& dllexport_decl);
+  explicit ExtensionGenerator(const FieldDescriptor* desycriptor,
+                              const Options& options);
   ~ExtensionGenerator();
 
   // Header stuff.
@@ -72,7 +73,7 @@ class ExtensionGenerator {
  private:
   const FieldDescriptor* descriptor_;
   string type_traits_;
-  string dllexport_decl_;
+  Options options_;
 
   GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(ExtensionGenerator);
 };
diff --git a/src/google/protobuf/compiler/cpp/cpp_field.cc b/src/google/protobuf/compiler/cpp/cpp_field.cc
index 103cac4a..0786176b 100644
--- a/src/google/protobuf/compiler/cpp/cpp_field.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_field.cc
@@ -52,7 +52,8 @@ namespace cpp {
 using internal::WireFormat;
 
 void SetCommonFieldVariables(const FieldDescriptor* descriptor,
-                             map<string, string>* variables) {
+                             map<string, string>* variables,
+                             const Options& options) {
   (*variables)["name"] = FieldName(descriptor);
   (*variables)["index"] = SimpleItoa(descriptor->index());
   (*variables)["number"] = SimpleItoa(descriptor->number());
@@ -64,6 +65,7 @@ void SetCommonFieldVariables(const FieldDescriptor* descriptor,
   (*variables)["deprecation"] = descriptor->options().deprecated()
       ? " PROTOBUF_DEPRECATED" : "";
 
+  (*variables)["cppget"] = "Get";
 }
 
 FieldGenerator::~FieldGenerator() {}
@@ -80,46 +82,47 @@ GenerateMergeFromCodedStreamWithPacking(io::Printer* printer) const {
 
 }
 
-FieldGeneratorMap::FieldGeneratorMap(const Descriptor* descriptor)
+FieldGeneratorMap::FieldGeneratorMap(const Descriptor* descriptor,
+                                     const Options& options)
   : descriptor_(descriptor),
-    field_generators_(
-      new scoped_ptr<FieldGenerator>[descriptor->field_count()]) {
+    field_generators_(new scoped_ptr<FieldGenerator>[descriptor->field_count()]) {
   // Construct all the FieldGenerators.
   for (int i = 0; i < descriptor->field_count(); i++) {
-    field_generators_[i].reset(MakeGenerator(descriptor->field(i)));
+    field_generators_[i].reset(MakeGenerator(descriptor->field(i), options));
   }
 }
 
-FieldGenerator* FieldGeneratorMap::MakeGenerator(const FieldDescriptor* field) {
+FieldGenerator* FieldGeneratorMap::MakeGenerator(const FieldDescriptor* field,
+                                                 const Options& options) {
   if (field->is_repeated()) {
     switch (field->cpp_type()) {
       case FieldDescriptor::CPPTYPE_MESSAGE:
-        return new RepeatedMessageFieldGenerator(field);
+        return new RepeatedMessageFieldGenerator(field, options);
       case FieldDescriptor::CPPTYPE_STRING:
         switch (field->options().ctype()) {
           default:  // RepeatedStringFieldGenerator handles unknown ctypes.
           case FieldOptions::STRING:
-            return new RepeatedStringFieldGenerator(field);
+            return new RepeatedStringFieldGenerator(field, options);
         }
       case FieldDescriptor::CPPTYPE_ENUM:
-        return new RepeatedEnumFieldGenerator(field);
+        return new RepeatedEnumFieldGenerator(field, options);
       default:
-        return new RepeatedPrimitiveFieldGenerator(field);
+        return new RepeatedPrimitiveFieldGenerator(field, options);
     }
   } else {
     switch (field->cpp_type()) {
       case FieldDescriptor::CPPTYPE_MESSAGE:
-        return new MessageFieldGenerator(field);
+        return new MessageFieldGenerator(field, options);
       case FieldDescriptor::CPPTYPE_STRING:
         switch (field->options().ctype()) {
           default:  // StringFieldGenerator handles unknown ctypes.
           case FieldOptions::STRING:
-            return new StringFieldGenerator(field);
+            return new StringFieldGenerator(field, options);
         }
       case FieldDescriptor::CPPTYPE_ENUM:
-        return new EnumFieldGenerator(field);
+        return new EnumFieldGenerator(field, options);
       default:
-        return new PrimitiveFieldGenerator(field);
+        return new PrimitiveFieldGenerator(field, options);
     }
   }
 }
diff --git a/src/google/protobuf/compiler/cpp/cpp_field.h b/src/google/protobuf/compiler/cpp/cpp_field.h
index c303a337..f7d99b15 100644
--- a/src/google/protobuf/compiler/cpp/cpp_field.h
+++ b/src/google/protobuf/compiler/cpp/cpp_field.h
@@ -40,6 +40,7 @@
 
 #include <google/protobuf/stubs/common.h>
 #include <google/protobuf/descriptor.h>
+#include <google/protobuf/compiler/cpp/cpp_options.h>
 
 namespace google {
 namespace protobuf {
@@ -57,7 +58,8 @@ namespace cpp {
 // ['name', 'index', 'number', 'classname', 'declared_type', 'tag_size',
 // 'deprecation'].
 void SetCommonFieldVariables(const FieldDescriptor* descriptor,
-                             map<string, string>* variables);
+                             map<string, string>* variables,
+                             const Options& options);
 
 class FieldGenerator {
  public:
@@ -114,6 +116,13 @@ class FieldGenerator {
   // Most field types don't need this, so the default implementation is empty.
   virtual void GenerateDestructorCode(io::Printer* printer) const {}
 
+  // Generate code that allocates the fields's default instance.
+  virtual void GenerateDefaultInstanceAllocator(io::Printer* printer) const {}
+
+  // Generate code that should be run when ShutdownProtobufLibrary() is called,
+  // to delete all dynamically-allocated objects.
+  virtual void GenerateShutdownCode(io::Printer* printer) const {}
+
   // Generate lines to decode this field, which will be placed inside the
   // message's MergeFromCodedStream() method.
   virtual void GenerateMergeFromCodedStream(io::Printer* printer) const = 0;
@@ -144,7 +153,7 @@ class FieldGenerator {
 // Convenience class which constructs FieldGenerators for a Descriptor.
 class FieldGeneratorMap {
  public:
-  explicit FieldGeneratorMap(const Descriptor* descriptor);
+  explicit FieldGeneratorMap(const Descriptor* descriptor, const Options& options);
   ~FieldGeneratorMap();
 
   const FieldGenerator& get(const FieldDescriptor* field) const;
@@ -153,7 +162,8 @@ class FieldGeneratorMap {
   const Descriptor* descriptor_;
   scoped_array<scoped_ptr<FieldGenerator> > field_generators_;
 
-  static FieldGenerator* MakeGenerator(const FieldDescriptor* field);
+  static FieldGenerator* MakeGenerator(const FieldDescriptor* field,
+                                       const Options& options);
 
   GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(FieldGeneratorMap);
 };
diff --git a/src/google/protobuf/compiler/cpp/cpp_file.cc b/src/google/protobuf/compiler/cpp/cpp_file.cc
index b8e7708f..1bbc89c4 100644
--- a/src/google/protobuf/compiler/cpp/cpp_file.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_file.cc
@@ -51,7 +51,7 @@ namespace cpp {
 // ===================================================================
 
 FileGenerator::FileGenerator(const FileDescriptor* file,
-                             const string& dllexport_decl)
+                             const Options& options)
   : file_(file),
     message_generators_(
       new scoped_ptr<MessageGenerator>[file->message_type_count()]),
@@ -61,26 +61,26 @@ FileGenerator::FileGenerator(const FileDescriptor* file,
       new scoped_ptr<ServiceGenerator>[file->service_count()]),
     extension_generators_(
       new scoped_ptr<ExtensionGenerator>[file->extension_count()]),
-    dllexport_decl_(dllexport_decl) {
+    options_(options) {
 
   for (int i = 0; i < file->message_type_count(); i++) {
     message_generators_[i].reset(
-      new MessageGenerator(file->message_type(i), dllexport_decl));
+      new MessageGenerator(file->message_type(i), options));
   }
 
   for (int i = 0; i < file->enum_type_count(); i++) {
     enum_generators_[i].reset(
-      new EnumGenerator(file->enum_type(i), dllexport_decl));
+      new EnumGenerator(file->enum_type(i), options));
   }
 
   for (int i = 0; i < file->service_count(); i++) {
     service_generators_[i].reset(
-      new ServiceGenerator(file->service(i), dllexport_decl));
+      new ServiceGenerator(file->service(i), options));
   }
 
   for (int i = 0; i < file->extension_count(); i++) {
     extension_generators_[i].reset(
-      new ExtensionGenerator(file->extension(i), dllexport_decl));
+      new ExtensionGenerator(file->extension(i), options));
   }
 
   SplitStringUsing(file_->package(), ".", &package_parts_);
@@ -104,6 +104,7 @@ void FileGenerator::GenerateHeader(io::Printer* printer) {
     "filename", file_->name(),
     "filename_identifier", filename_identifier);
 
+
   printer->Print(
     "#include <google/protobuf/stubs/common.h>\n"
     "\n");
@@ -128,13 +129,23 @@ void FileGenerator::GenerateHeader(io::Printer* printer) {
 
   // OK, it's now safe to #include other files.
   printer->Print(
-    "#include <google/protobuf/generated_message_util.h>\n"
+    "#include <google/protobuf/generated_message_util.h>\n");
+  if (file_->message_type_count() > 0) {
+    if (HasDescriptorMethods(file_)) {
+      printer->Print(
+        "#include <google/protobuf/message.h>\n");
+    } else {
+      printer->Print(
+        "#include <google/protobuf/message_lite.h>\n");
+    }
+  }
+  printer->Print(
     "#include <google/protobuf/repeated_field.h>\n"
     "#include <google/protobuf/extension_set.h>\n");
 
-  if (HasDescriptorMethods(file_)) {
+  if (HasDescriptorMethods(file_) && HasEnumDefinitions(file_)) {
     printer->Print(
-      "#include <google/protobuf/generated_message_reflection.h>\n");
+      "#include <google/protobuf/generated_enum_reflection.h>\n");
   }
 
   if (HasGenericServices(file_)) {
@@ -142,6 +153,11 @@ void FileGenerator::GenerateHeader(io::Printer* printer) {
       "#include <google/protobuf/service.h>\n");
   }
 
+  if (HasUnknownFields(file_) && file_->message_type_count() > 0) {
+    printer->Print(
+      "#include <google/protobuf/unknown_field_set.h>\n");
+  }
+
 
   for (int i = 0; i < file_->dependency_count(); i++) {
     printer->Print(
@@ -149,9 +165,11 @@ void FileGenerator::GenerateHeader(io::Printer* printer) {
       "dependency", StripProto(file_->dependency(i)->name()));
   }
 
+
   printer->Print(
     "// @@protoc_insertion_point(includes)\n");
 
+
   // Open namespace.
   GenerateNamespaceOpeners(printer);
 
@@ -162,7 +180,7 @@ void FileGenerator::GenerateHeader(io::Printer* printer) {
     "// Internal implementation detail -- do not call these.\n"
     "void $dllexport_decl$ $adddescriptorsname$();\n",
     "adddescriptorsname", GlobalAddDescriptorsName(file_->name()),
-    "dllexport_decl", dllexport_decl_);
+    "dllexport_decl", options_.dllexport_decl);
 
   printer->Print(
     // Note that we don't put dllexport_decl on these because they are only
@@ -282,6 +300,7 @@ void FileGenerator::GenerateHeader(io::Printer* printer) {
 void FileGenerator::GenerateSource(io::Printer* printer) {
   printer->Print(
     "// Generated by the protocol buffer compiler.  DO NOT EDIT!\n"
+    "// source: $filename$\n"
     "\n"
 
     // The generated code calls accessors that might be deprecated. We don't
@@ -294,11 +313,13 @@ void FileGenerator::GenerateSource(io::Printer* printer) {
     "#include <google/protobuf/stubs/once.h>\n"
     "#include <google/protobuf/io/coded_stream.h>\n"
     "#include <google/protobuf/wire_format_lite_inl.h>\n",
+    "filename", file_->name(),
     "basename", StripProto(file_->name()));
 
   if (HasDescriptorMethods(file_)) {
     printer->Print(
       "#include <google/protobuf/descriptor.h>\n"
+      "#include <google/protobuf/generated_message_reflection.h>\n"
       "#include <google/protobuf/reflection_ops.h>\n"
       "#include <google/protobuf/wire_format.h>\n");
   }
@@ -504,10 +525,12 @@ void FileGenerator::GenerateBuildDescriptors(io::Printer* printer) {
     "  static bool already_here = false;\n"
     "  if (already_here) return;\n"
     "  already_here = true;\n"
-    "  GOOGLE_PROTOBUF_VERIFY_VERSION;\n",
+    "  GOOGLE_PROTOBUF_VERIFY_VERSION;\n"
+    "\n",
     // Without.
     "void $adddescriptorsname$_impl() {\n"
-    "  GOOGLE_PROTOBUF_VERIFY_VERSION;\n",
+    "  GOOGLE_PROTOBUF_VERIFY_VERSION;\n"
+    "\n",
     // Vars.
     "adddescriptorsname", GlobalAddDescriptorsName(file_->name()));
 
@@ -521,9 +544,9 @@ void FileGenerator::GenerateBuildDescriptors(io::Printer* printer) {
     vector<string> dependency_package_parts;
     SplitStringUsing(dependency->package(), ".", &dependency_package_parts);
     printer->Print("::");
-    for (int i = 0; i < dependency_package_parts.size(); i++) {
+    for (int j = 0; j < dependency_package_parts.size(); j++) {
       printer->Print("$name$::",
-                     "name", dependency_package_parts[i]);
+                     "name", dependency_package_parts[j]);
     }
     // Call its AddDescriptors function.
     printer->Print(
@@ -547,10 +570,12 @@ void FileGenerator::GenerateBuildDescriptors(io::Printer* printer) {
     static const int kBytesPerLine = 40;
     for (int i = 0; i < file_data.size(); i += kBytesPerLine) {
       printer->Print("\n  \"$data$\"",
-        "data", EscapeTrigraphs(CEscape(file_data.substr(i, kBytesPerLine))));
+                     "data",
+                     EscapeTrigraphs(
+                         CEscape(file_data.substr(i, kBytesPerLine))));
     }
     printer->Print(
-      ", $size$);\n",
+        ", $size$);\n",
       "size", SimpleItoa(file_data.size()));
 
     // Call MessageFactory::InternalRegisterGeneratedFile().
@@ -594,7 +619,7 @@ void FileGenerator::GenerateBuildDescriptors(io::Printer* printer) {
     // Without.
     "GOOGLE_PROTOBUF_DECLARE_ONCE($adddescriptorsname$_once_);\n"
     "void $adddescriptorsname$() {\n"
-    "  ::google::protobuf::GoogleOnceInit(&$adddescriptorsname$_once_,\n"
+    "  ::google::protobuf::::google::protobuf::GoogleOnceInit(&$adddescriptorsname$_once_,\n"
     "                 &$adddescriptorsname$_impl);\n"
     "}\n",
     // Vars.
diff --git a/src/google/protobuf/compiler/cpp/cpp_file.h b/src/google/protobuf/compiler/cpp/cpp_file.h
index b4e01285..2deefaa8 100644
--- a/src/google/protobuf/compiler/cpp/cpp_file.h
+++ b/src/google/protobuf/compiler/cpp/cpp_file.h
@@ -39,6 +39,7 @@
 #include <vector>
 #include <google/protobuf/stubs/common.h>
 #include <google/protobuf/compiler/cpp/cpp_field.h>
+#include <google/protobuf/compiler/cpp/cpp_options.h>
 
 namespace google {
 namespace protobuf {
@@ -61,7 +62,7 @@ class FileGenerator {
  public:
   // See generator.cc for the meaning of dllexport_decl.
   explicit FileGenerator(const FileDescriptor* file,
-                         const string& dllexport_decl);
+                         const Options& options);
   ~FileGenerator();
 
   void GenerateHeader(io::Printer* printer);
@@ -85,7 +86,7 @@ class FileGenerator {
   // E.g. if the package is foo.bar, package_parts_ is {"foo", "bar"}.
   vector<string> package_parts_;
 
-  string dllexport_decl_;
+  const Options options_;
 
   GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(FileGenerator);
 };
diff --git a/src/google/protobuf/compiler/cpp/cpp_generator.cc b/src/google/protobuf/compiler/cpp/cpp_generator.cc
index bb84e2ab..1813510b 100644
--- a/src/google/protobuf/compiler/cpp/cpp_generator.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_generator.cc
@@ -78,11 +78,13 @@ bool CppGenerator::Generate(const FileDescriptor* file,
   //   }
   // FOO_EXPORT is a macro which should expand to __declspec(dllexport) or
   // __declspec(dllimport) depending on what is being compiled.
-  string dllexport_decl;
+  Options file_options;
 
   for (int i = 0; i < options.size(); i++) {
     if (options[i].first == "dllexport_decl") {
-      dllexport_decl = options[i].second;
+      file_options.dllexport_decl = options[i].second;
+    } else if (options[i].first == "safe_boundary_check") {
+      file_options.safe_boundary_check = true;
     } else {
       *error = "Unknown generator option: " + options[i].first;
       return false;
@@ -95,7 +97,7 @@ bool CppGenerator::Generate(const FileDescriptor* file,
   string basename = StripProto(file->name());
   basename.append(".pb");
 
-  FileGenerator file_generator(file, dllexport_decl);
+  FileGenerator file_generator(file, file_options);
 
   // Generate header.
   {
diff --git a/src/google/protobuf/compiler/cpp/cpp_helpers.cc b/src/google/protobuf/compiler/cpp/cpp_helpers.cc
index c4b868c2..28911ab0 100644
--- a/src/google/protobuf/compiler/cpp/cpp_helpers.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_helpers.cc
@@ -148,7 +148,7 @@ string ClassName(const Descriptor* descriptor, bool qualified) {
 string ClassName(const EnumDescriptor* enum_descriptor, bool qualified) {
   if (enum_descriptor->containing_type() == NULL) {
     if (qualified) {
-      return DotsToColons(enum_descriptor->full_name());
+      return "::" + DotsToColons(enum_descriptor->full_name());
     } else {
       return enum_descriptor->name();
     }
@@ -259,10 +259,23 @@ const char* DeclaredTypeMethodName(FieldDescriptor::Type type) {
 string DefaultValue(const FieldDescriptor* field) {
   switch (field->cpp_type()) {
     case FieldDescriptor::CPPTYPE_INT32:
+      // gcc rejects the decimal form of kint32min and kint64min.
+      if (field->default_value_int32() == kint32min) {
+        // Make sure we are in a 2's complement system.
+        GOOGLE_COMPILE_ASSERT(kint32min == -0x80000000, kint32min_value_error);
+        return "-0x80000000";
+      }
       return SimpleItoa(field->default_value_int32());
     case FieldDescriptor::CPPTYPE_UINT32:
       return SimpleItoa(field->default_value_uint32()) + "u";
     case FieldDescriptor::CPPTYPE_INT64:
+      // See the comments for CPPTYPE_INT32.
+      if (field->default_value_int64() == kint64min) {
+        // Make sure we are in a 2's complement system.
+        GOOGLE_COMPILE_ASSERT(kint64min == GOOGLE_LONGLONG(-0x8000000000000000),
+                       kint64min_value_error);
+        return "GOOGLE_LONGLONG(-0x8000000000000000)";
+      }
       return "GOOGLE_LONGLONG(" + SimpleItoa(field->default_value_int64()) + ")";
     case FieldDescriptor::CPPTYPE_UINT64:
       return "GOOGLE_ULONGLONG(" + SimpleItoa(field->default_value_uint64())+ ")";
@@ -308,8 +321,9 @@ string DefaultValue(const FieldDescriptor* field) {
           ClassName(field->enum_type(), true),
           field->default_value_enum()->number());
     case FieldDescriptor::CPPTYPE_STRING:
-      return "\"" + EscapeTrigraphs(CEscape(field->default_value_string())) +
-             "\"";
+      return "\"" + EscapeTrigraphs(
+        CEscape(field->default_value_string())) +
+        "\"";
     case FieldDescriptor::CPPTYPE_MESSAGE:
       return FieldMessageTypeName(field) + "::default_instance()";
   }
@@ -401,6 +415,23 @@ void PrintHandlingOptionalStaticInitializers(
   }
 }
 
+
+static bool HasEnumDefinitions(const Descriptor* message_type) {
+  if (message_type->enum_type_count() > 0) return true;
+  for (int i = 0; i < message_type->nested_type_count(); ++i) {
+    if (HasEnumDefinitions(message_type->nested_type(i))) return true;
+  }
+  return false;
+}
+
+bool HasEnumDefinitions(const FileDescriptor* file) {
+  if (file->enum_type_count() > 0) return true;
+  for (int i = 0; i < file->message_type_count(); ++i) {
+    if (HasEnumDefinitions(file->message_type(i))) return true;
+  }
+  return false;
+}
+
 }  // namespace cpp
 }  // namespace compiler
 }  // namespace protobuf
diff --git a/src/google/protobuf/compiler/cpp/cpp_helpers.h b/src/google/protobuf/compiler/cpp/cpp_helpers.h
index 662a7c31..526e19cc 100644
--- a/src/google/protobuf/compiler/cpp/cpp_helpers.h
+++ b/src/google/protobuf/compiler/cpp/cpp_helpers.h
@@ -122,23 +122,27 @@ string GlobalShutdownFileName(const string& filename);
 string EscapeTrigraphs(const string& to_escape);
 
 // Do message classes in this file keep track of unknown fields?
-inline bool HasUnknownFields(const FileDescriptor *file) {
+inline bool HasUnknownFields(const FileDescriptor* file) {
   return file->options().optimize_for() != FileOptions::LITE_RUNTIME;
 }
 
+
+// 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) {
+inline bool HasGeneratedMethods(const FileDescriptor* file) {
   return file->options().optimize_for() != FileOptions::CODE_SIZE;
 }
 
-// Do message classes in this file have descriptor and refelction methods?
-inline bool HasDescriptorMethods(const FileDescriptor *file) {
+// Do message classes in this file have descriptor and reflection methods?
+inline bool HasDescriptorMethods(const FileDescriptor* file) {
   return file->options().optimize_for() != FileOptions::LITE_RUNTIME;
 }
 
 // Should we generate generic services for this file?
-inline bool HasGenericServices(const FileDescriptor *file) {
+inline bool HasGenericServices(const FileDescriptor* file) {
   return file->service_count() > 0 &&
          file->options().optimize_for() != FileOptions::LITE_RUNTIME &&
          file->options().cc_generic_services();
@@ -173,6 +177,7 @@ void PrintHandlingOptionalStaticInitializers(
     io::Printer* printer, const char* with_static_init,
     const char* without_static_init);
 
+
 }  // namespace cpp
 }  // namespace compiler
 }  // namespace protobuf
diff --git a/src/google/protobuf/compiler/cpp/cpp_message.cc b/src/google/protobuf/compiler/cpp/cpp_message.cc
index 1c158be0..1ea4f13d 100644
--- a/src/google/protobuf/compiler/cpp/cpp_message.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_message.cc
@@ -48,6 +48,7 @@
 #include <google/protobuf/wire_format.h>
 #include <google/protobuf/descriptor.pb.h>
 
+
 namespace google {
 namespace protobuf {
 namespace compiler {
@@ -103,6 +104,13 @@ struct ExtensionRangeSorter {
   }
 };
 
+// Returns true if the "required" restriction check should be ignored for the
+// given field.
+inline static bool ShouldIgnoreRequiredFieldCheck(
+    const FieldDescriptor* field) {
+  return false;
+}
+
 // Returns true if the message type has any required fields.  If it doesn't,
 // we can optimize out calls to its IsInitialized() method.
 //
@@ -129,7 +137,8 @@ static bool HasRequiredFields(
     if (field->is_required()) {
       return true;
     }
-    if (field->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE) {
+    if (field->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE &&
+        !ShouldIgnoreRequiredFieldCheck(field)) {
       if (HasRequiredFields(field->message_type(), already_seen)) {
         return true;
       }
@@ -280,11 +289,11 @@ void OptimizePadding(vector<const FieldDescriptor*>* fields) {
 // ===================================================================
 
 MessageGenerator::MessageGenerator(const Descriptor* descriptor,
-                                   const string& dllexport_decl)
+                                   const Options& options)
   : descriptor_(descriptor),
     classname_(ClassName(descriptor, false)),
-    dllexport_decl_(dllexport_decl),
-    field_generators_(descriptor),
+    options_(options),
+    field_generators_(descriptor, options),
     nested_generators_(new scoped_ptr<MessageGenerator>[
       descriptor->nested_type_count()]),
     enum_generators_(new scoped_ptr<EnumGenerator>[
@@ -294,17 +303,17 @@ MessageGenerator::MessageGenerator(const Descriptor* descriptor,
 
   for (int i = 0; i < descriptor->nested_type_count(); i++) {
     nested_generators_[i].reset(
-      new MessageGenerator(descriptor->nested_type(i), dllexport_decl));
+      new MessageGenerator(descriptor->nested_type(i), options));
   }
 
   for (int i = 0; i < descriptor->enum_type_count(); i++) {
     enum_generators_[i].reset(
-      new EnumGenerator(descriptor->enum_type(i), dllexport_decl));
+      new EnumGenerator(descriptor->enum_type(i), options));
   }
 
   for (int i = 0; i < descriptor->extension_count(); i++) {
     extension_generators_[i].reset(
-      new ExtensionGenerator(descriptor->extension(i), dllexport_decl));
+      new ExtensionGenerator(descriptor->extension(i), options));
   }
 }
 
@@ -349,7 +358,7 @@ GenerateFieldAccessorDeclarations(io::Printer* printer) {
     PrintFieldComment(printer, field);
 
     map<string, string> vars;
-    SetCommonFieldVariables(field, &vars);
+    SetCommonFieldVariables(field, &vars, options_);
     vars["constant_name"] = FieldConstantName(field);
 
     if (field->is_repeated()) {
@@ -386,7 +395,7 @@ GenerateFieldAccessorDefinitions(io::Printer* printer) {
     PrintFieldComment(printer, field);
 
     map<string, string> vars;
-    SetCommonFieldVariables(field, &vars);
+    SetCommonFieldVariables(field, &vars, options_);
 
     // Generate has_$name$() or $name$_size().
     if (field->is_repeated()) {
@@ -446,10 +455,10 @@ GenerateClassDefinition(io::Printer* printer) {
   map<string, string> vars;
   vars["classname"] = classname_;
   vars["field_count"] = SimpleItoa(descriptor_->field_count());
-  if (dllexport_decl_.empty()) {
+  if (options_.dllexport_decl.empty()) {
     vars["dllexport"] = "";
   } else {
-    vars["dllexport"] = dllexport_decl_ + " ";
+    vars["dllexport"] = options_.dllexport_decl + " ";
   }
   vars["superclass"] = SuperClassName(descriptor_);
 
@@ -507,6 +516,7 @@ GenerateClassDefinition(io::Printer* printer) {
       "\n");
   }
 
+
   printer->Print(vars,
     "void Swap($classname$* other);\n"
     "\n"
@@ -605,6 +615,7 @@ GenerateClassDefinition(io::Printer* printer) {
   printer->Print(" private:\n");
   printer->Indent();
 
+
   for (int i = 0; i < descriptor_->field_count(); i++) {
     if (!descriptor_->field(i)->is_repeated()) {
       printer->Print(
@@ -680,7 +691,7 @@ GenerateClassDefinition(io::Printer* printer) {
     // Without.
     "friend void $dllexport_decl$ $adddescriptorsname$_impl();\n",
     // Vars.
-    "dllexport_decl", dllexport_decl_,
+    "dllexport_decl", options_.dllexport_decl,
     "adddescriptorsname",
     GlobalAddDescriptorsName(descriptor_->file()->name()));
 
@@ -772,9 +783,11 @@ GenerateDescriptorInitializer(io::Printer* printer, int index) {
     printer->Print(vars,
       "    -1,\n");
   }
+  printer->Print(
+    "    ::google::protobuf::DescriptorPool::generated_pool(),\n");
+  printer->Print(vars,
+    "    ::google::protobuf::MessageFactory::generated_factory(),\n");
   printer->Print(vars,
-    "    ::google::protobuf::DescriptorPool::generated_pool(),\n"
-    "    ::google::protobuf::MessageFactory::generated_factory(),\n"
     "    sizeof($classname$));\n");
 
   // Handle nested types.
@@ -803,6 +816,13 @@ GenerateTypeRegistrations(io::Printer* printer) {
 
 void MessageGenerator::
 GenerateDefaultInstanceAllocator(io::Printer* printer) {
+  // Construct the default instances of all fields, as they will be used
+  // when creating the default instance of the entire message.
+  for (int i = 0; i < descriptor_->field_count(); i++) {
+    field_generators_.get(descriptor_->field(i))
+                     .GenerateDefaultInstanceAllocator(printer);
+  }
+
   // Construct the default instance.  We can't call InitAsDefaultInstance() yet
   // because we need to make sure all default instances that this one might
   // depend on are constructed first.
@@ -846,6 +866,12 @@ GenerateShutdownCode(io::Printer* printer) {
       "classname", classname_);
   }
 
+  // Handle default instances of fields.
+  for (int i = 0; i < descriptor_->field_count(); i++) {
+    field_generators_.get(descriptor_->field(i))
+                     .GenerateShutdownCode(printer);
+  }
+
   // Handle nested types.
   for (int i = 0; i < descriptor_->nested_type_count(); i++) {
     nested_generators_[i]->GenerateShutdownCode(printer);
@@ -1957,6 +1983,7 @@ GenerateIsInitialized(io::Printer* printer) {
   for (int i = 0; i < descriptor_->field_count(); i++) {
     const FieldDescriptor* field = descriptor_->field(i);
     if (field->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE &&
+        !ShouldIgnoreRequiredFieldCheck(field) &&
         HasRequiredFields(field->message_type())) {
       if (field->is_repeated()) {
         printer->Print(
diff --git a/src/google/protobuf/compiler/cpp/cpp_message.h b/src/google/protobuf/compiler/cpp/cpp_message.h
index 04778f6d..a7e43d9c 100644
--- a/src/google/protobuf/compiler/cpp/cpp_message.h
+++ b/src/google/protobuf/compiler/cpp/cpp_message.h
@@ -38,6 +38,7 @@
 #include <string>
 #include <google/protobuf/stubs/common.h>
 #include <google/protobuf/compiler/cpp/cpp_field.h>
+#include <google/protobuf/compiler/cpp/cpp_options.h>
 
 namespace google {
 namespace protobuf {
@@ -57,7 +58,7 @@ class MessageGenerator {
  public:
   // See generator.cc for the meaning of dllexport_decl.
   explicit MessageGenerator(const Descriptor* descriptor,
-                            const string& dllexport_decl);
+                            const Options& options);
   ~MessageGenerator();
 
   // Header stuff.
@@ -153,7 +154,7 @@ class MessageGenerator {
 
   const Descriptor* descriptor_;
   string classname_;
-  string dllexport_decl_;
+  Options options_;
   FieldGeneratorMap field_generators_;
   scoped_array<scoped_ptr<MessageGenerator> > nested_generators_;
   scoped_array<scoped_ptr<EnumGenerator> > enum_generators_;
diff --git a/src/google/protobuf/compiler/cpp/cpp_message_field.cc b/src/google/protobuf/compiler/cpp/cpp_message_field.cc
index 7c785e7e..447f975f 100644
--- a/src/google/protobuf/compiler/cpp/cpp_message_field.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_message_field.cc
@@ -45,8 +45,9 @@ namespace cpp {
 namespace {
 
 void SetMessageVariables(const FieldDescriptor* descriptor,
-                         map<string, string>* variables) {
-  SetCommonFieldVariables(descriptor, variables);
+                         map<string, string>* variables,
+                         const Options& options) {
+  SetCommonFieldVariables(descriptor, variables, options);
   (*variables)["type"] = FieldMessageTypeName(descriptor);
   (*variables)["stream_writer"] = (*variables)["declared_type"] +
       (HasFastArraySerialization(descriptor->message_type()->file()) ?
@@ -59,9 +60,10 @@ void SetMessageVariables(const FieldDescriptor* descriptor,
 // ===================================================================
 
 MessageFieldGenerator::
-MessageFieldGenerator(const FieldDescriptor* descriptor)
+MessageFieldGenerator(const FieldDescriptor* descriptor,
+                      const Options& options)
   : descriptor_(descriptor) {
-  SetMessageVariables(descriptor, &variables_);
+  SetMessageVariables(descriptor, &variables_, options);
 }
 
 MessageFieldGenerator::~MessageFieldGenerator() {}
@@ -76,7 +78,8 @@ GenerateAccessorDeclarations(io::Printer* printer) const {
   printer->Print(variables_,
     "inline const $type$& $name$() const$deprecation$;\n"
     "inline $type$* mutable_$name$()$deprecation$;\n"
-    "inline $type$* release_$name$()$deprecation$;\n");
+    "inline $type$* release_$name$()$deprecation$;\n"
+    "inline void set_allocated_$name$($type$* $name$)$deprecation$;\n");
 }
 
 void MessageFieldGenerator::
@@ -103,6 +106,15 @@ GenerateInlineAccessorDefinitions(io::Printer* printer) const {
     "  $type$* temp = $name$_;\n"
     "  $name$_ = NULL;\n"
     "  return temp;\n"
+    "}\n"
+    "inline void $classname$::set_allocated_$name$($type$* $name$) {\n"
+    "  delete $name$_;\n"
+    "  $name$_ = $name$;\n"
+    "  if ($name$) {\n"
+    "    set_has_$name$();\n"
+    "  } else {\n"
+    "    clear_has_$name$();\n"
+    "  }\n"
     "}\n");
 }
 
@@ -167,9 +179,10 @@ GenerateByteSize(io::Printer* printer) const {
 // ===================================================================
 
 RepeatedMessageFieldGenerator::
-RepeatedMessageFieldGenerator(const FieldDescriptor* descriptor)
+RepeatedMessageFieldGenerator(const FieldDescriptor* descriptor,
+                              const Options& options)
   : descriptor_(descriptor) {
-  SetMessageVariables(descriptor, &variables_);
+  SetMessageVariables(descriptor, &variables_, options);
 }
 
 RepeatedMessageFieldGenerator::~RepeatedMessageFieldGenerator() {}
@@ -197,7 +210,7 @@ void RepeatedMessageFieldGenerator::
 GenerateInlineAccessorDefinitions(io::Printer* printer) const {
   printer->Print(variables_,
     "inline const $type$& $classname$::$name$(int index) const {\n"
-    "  return $name$_.Get(index);\n"
+    "  return $name$_.$cppget$(index);\n"
     "}\n"
     "inline $type$* $classname$::mutable_$name$(int index) {\n"
     "  return $name$_.Mutable(index);\n"
diff --git a/src/google/protobuf/compiler/cpp/cpp_message_field.h b/src/google/protobuf/compiler/cpp/cpp_message_field.h
index f5147278..a5ed68a5 100644
--- a/src/google/protobuf/compiler/cpp/cpp_message_field.h
+++ b/src/google/protobuf/compiler/cpp/cpp_message_field.h
@@ -46,7 +46,8 @@ namespace cpp {
 
 class MessageFieldGenerator : public FieldGenerator {
  public:
-  explicit MessageFieldGenerator(const FieldDescriptor* descriptor);
+  explicit MessageFieldGenerator(const FieldDescriptor* descriptor,
+                                 const Options& options);
   ~MessageFieldGenerator();
 
   // implements FieldGenerator ---------------------------------------
@@ -71,7 +72,8 @@ class MessageFieldGenerator : public FieldGenerator {
 
 class RepeatedMessageFieldGenerator : public FieldGenerator {
  public:
-  explicit RepeatedMessageFieldGenerator(const FieldDescriptor* descriptor);
+  explicit RepeatedMessageFieldGenerator(const FieldDescriptor* descriptor,
+                                         const Options& options);
   ~RepeatedMessageFieldGenerator();
 
   // implements FieldGenerator ---------------------------------------
diff --git a/src/google/protobuf/compiler/cpp/cpp_options.h b/src/google/protobuf/compiler/cpp/cpp_options.h
new file mode 100644
index 00000000..78770662
--- /dev/null
+++ b/src/google/protobuf/compiler/cpp/cpp_options.h
@@ -0,0 +1,58 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// 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: rennie@google.com (Jeffrey Rennie)
+
+#ifndef GOOGLE_PROTOBUF_COMPILER_CPP_OPTIONS_H__
+#define GOOGLE_PROTOBUF_COMPILER_CPP_OPTIONS_H__
+
+#include <string>
+
+#include <google/protobuf/stubs/common.h>
+namespace google {
+namespace protobuf {
+namespace compiler {
+namespace cpp {
+
+// Generator options:
+struct Options {
+  Options() : safe_boundary_check(false) {
+  }
+  string dllexport_decl;
+  bool safe_boundary_check;
+};
+
+}  // namespace cpp
+}  // namespace compiler
+}  // namespace protobuf
+
+
+}  // namespace google
+#endif  // GOOGLE_PROTOBUF_COMPILER_CPP_OPTIONS_H__
diff --git a/src/google/protobuf/compiler/cpp/cpp_primitive_field.cc b/src/google/protobuf/compiler/cpp/cpp_primitive_field.cc
index 5e8df0f4..1c35fefa 100644
--- a/src/google/protobuf/compiler/cpp/cpp_primitive_field.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_primitive_field.cc
@@ -80,8 +80,9 @@ int FixedSize(FieldDescriptor::Type type) {
 }
 
 void SetPrimitiveVariables(const FieldDescriptor* descriptor,
-                           map<string, string>* variables) {
-  SetCommonFieldVariables(descriptor, variables);
+                           map<string, string>* variables,
+                           const Options& options) {
+  SetCommonFieldVariables(descriptor, variables, options);
   (*variables)["type"] = PrimitiveTypeName(descriptor->cpp_type());
   (*variables)["default"] = DefaultValue(descriptor);
   (*variables)["tag"] = SimpleItoa(internal::WireFormat::MakeTag(descriptor));
@@ -99,9 +100,10 @@ void SetPrimitiveVariables(const FieldDescriptor* descriptor,
 // ===================================================================
 
 PrimitiveFieldGenerator::
-PrimitiveFieldGenerator(const FieldDescriptor* descriptor)
+PrimitiveFieldGenerator(const FieldDescriptor* descriptor,
+                        const Options& options)
   : descriptor_(descriptor) {
-  SetPrimitiveVariables(descriptor, &variables_);
+  SetPrimitiveVariables(descriptor, &variables_, options);
 }
 
 PrimitiveFieldGenerator::~PrimitiveFieldGenerator() {}
@@ -190,9 +192,10 @@ GenerateByteSize(io::Printer* printer) const {
 // ===================================================================
 
 RepeatedPrimitiveFieldGenerator::
-RepeatedPrimitiveFieldGenerator(const FieldDescriptor* descriptor)
+RepeatedPrimitiveFieldGenerator(const FieldDescriptor* descriptor,
+                                const Options& options)
   : descriptor_(descriptor) {
-  SetPrimitiveVariables(descriptor, &variables_);
+  SetPrimitiveVariables(descriptor, &variables_, options);
 
   if (descriptor->options().packed()) {
     variables_["packed_reader"] = "ReadPackedPrimitive";
@@ -366,7 +369,9 @@ GenerateByteSize(io::Printer* printer) const {
       "  total_size += $tag_size$ +\n"
       "    ::google::protobuf::internal::WireFormatLite::Int32Size(data_size);\n"
       "}\n"
+      "GOOGLE_SAFE_CONCURRENT_WRITES_BEGIN();\n"
       "_$name$_cached_byte_size_ = data_size;\n"
+      "GOOGLE_SAFE_CONCURRENT_WRITES_END();\n"
       "total_size += data_size;\n");
   } else {
     printer->Print(variables_,
diff --git a/src/google/protobuf/compiler/cpp/cpp_primitive_field.h b/src/google/protobuf/compiler/cpp/cpp_primitive_field.h
index 8fcd74ae..48249c40 100644
--- a/src/google/protobuf/compiler/cpp/cpp_primitive_field.h
+++ b/src/google/protobuf/compiler/cpp/cpp_primitive_field.h
@@ -46,7 +46,8 @@ namespace cpp {
 
 class PrimitiveFieldGenerator : public FieldGenerator {
  public:
-  explicit PrimitiveFieldGenerator(const FieldDescriptor* descriptor);
+  explicit PrimitiveFieldGenerator(const FieldDescriptor* descriptor,
+                                   const Options& options);
   ~PrimitiveFieldGenerator();
 
   // implements FieldGenerator ---------------------------------------
@@ -71,7 +72,8 @@ class PrimitiveFieldGenerator : public FieldGenerator {
 
 class RepeatedPrimitiveFieldGenerator : public FieldGenerator {
  public:
-  explicit RepeatedPrimitiveFieldGenerator(const FieldDescriptor* descriptor);
+  explicit RepeatedPrimitiveFieldGenerator(const FieldDescriptor* descriptor,
+                                           const Options& options);
   ~RepeatedPrimitiveFieldGenerator();
 
   // implements FieldGenerator ---------------------------------------
diff --git a/src/google/protobuf/compiler/cpp/cpp_service.cc b/src/google/protobuf/compiler/cpp/cpp_service.cc
index c2825683..d20018ea 100644
--- a/src/google/protobuf/compiler/cpp/cpp_service.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_service.cc
@@ -43,14 +43,14 @@ namespace compiler {
 namespace cpp {
 
 ServiceGenerator::ServiceGenerator(const ServiceDescriptor* descriptor,
-                                   const string& dllexport_decl)
+                                   const Options& options)
   : descriptor_(descriptor) {
   vars_["classname"] = descriptor_->name();
   vars_["full_name"] = descriptor_->full_name();
-  if (dllexport_decl.empty()) {
+  if (options.dllexport_decl.empty()) {
     vars_["dllexport"] = "";
   } else {
-    vars_["dllexport"] = dllexport_decl + " ";
+    vars_["dllexport"] = options.dllexport_decl + " ";
   }
 }
 
diff --git a/src/google/protobuf/compiler/cpp/cpp_service.h b/src/google/protobuf/compiler/cpp/cpp_service.h
index 10e9dd3c..820f9f5f 100644
--- a/src/google/protobuf/compiler/cpp/cpp_service.h
+++ b/src/google/protobuf/compiler/cpp/cpp_service.h
@@ -38,6 +38,7 @@
 #include <map>
 #include <string>
 #include <google/protobuf/stubs/common.h>
+#include <google/protobuf/compiler/cpp/cpp_options.h>
 #include <google/protobuf/descriptor.h>
 
 namespace google {
@@ -55,7 +56,7 @@ class ServiceGenerator {
  public:
   // See generator.cc for the meaning of dllexport_decl.
   explicit ServiceGenerator(const ServiceDescriptor* descriptor,
-                            const string& dllexport_decl);
+                            const Options& options);
   ~ServiceGenerator();
 
   // Header stuff.
diff --git a/src/google/protobuf/compiler/cpp/cpp_string_field.cc b/src/google/protobuf/compiler/cpp/cpp_string_field.cc
index 3cec2b6b..9c0911ac 100644
--- a/src/google/protobuf/compiler/cpp/cpp_string_field.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_string_field.cc
@@ -46,11 +46,14 @@ namespace cpp {
 namespace {
 
 void SetStringVariables(const FieldDescriptor* descriptor,
-                        map<string, string>* variables) {
-  SetCommonFieldVariables(descriptor, variables);
+                        map<string, string>* variables,
+                        const Options& options) {
+  SetCommonFieldVariables(descriptor, variables, options);
   (*variables)["default"] = DefaultValue(descriptor);
+  (*variables)["default_length"] =
+      SimpleItoa(descriptor->default_value_string().length());
   (*variables)["default_variable"] = descriptor->default_value_string().empty()
-      ? "::google::protobuf::internal::kEmptyString"
+      ? "&::google::protobuf::internal::kEmptyString"
       : "_default_" + FieldName(descriptor) + "_";
   (*variables)["pointer_type"] =
       descriptor->type() == FieldDescriptor::TYPE_BYTES ? "void" : "char";
@@ -61,9 +64,10 @@ void SetStringVariables(const FieldDescriptor* descriptor,
 // ===================================================================
 
 StringFieldGenerator::
-StringFieldGenerator(const FieldDescriptor* descriptor)
+StringFieldGenerator(const FieldDescriptor* descriptor,
+                     const Options& options)
   : descriptor_(descriptor) {
-  SetStringVariables(descriptor, &variables_);
+  SetStringVariables(descriptor, &variables_, options);
 }
 
 StringFieldGenerator::~StringFieldGenerator() {}
@@ -72,7 +76,7 @@ void StringFieldGenerator::
 GeneratePrivateMembers(io::Printer* printer) const {
   printer->Print(variables_, "::std::string* $name$_;\n");
   if (!descriptor_->default_value_string().empty()) {
-    printer->Print(variables_, "static const ::std::string $default_variable$;\n");
+    printer->Print(variables_, "static ::std::string* $default_variable$;\n");
   }
 }
 
@@ -109,7 +113,9 @@ GenerateAccessorDeclarations(io::Printer* printer) const {
     "inline void set_$name$(const $pointer_type$* value, size_t size)"
                  "$deprecation$;\n"
     "inline ::std::string* mutable_$name$()$deprecation$;\n"
-    "inline ::std::string* release_$name$()$deprecation$;\n");
+    "inline ::std::string* release_$name$()$deprecation$;\n"
+    "inline void set_allocated_$name$(::std::string* $name$)$deprecation$;\n");
+
 
   if (descriptor_->options().ctype() != FieldOptions::STRING) {
     printer->Outdent();
@@ -126,14 +132,14 @@ GenerateInlineAccessorDefinitions(io::Printer* printer) const {
     "}\n"
     "inline void $classname$::set_$name$(const ::std::string& value) {\n"
     "  set_has_$name$();\n"
-    "  if ($name$_ == &$default_variable$) {\n"
+    "  if ($name$_ == $default_variable$) {\n"
     "    $name$_ = new ::std::string;\n"
     "  }\n"
     "  $name$_->assign(value);\n"
     "}\n"
     "inline void $classname$::set_$name$(const char* value) {\n"
     "  set_has_$name$();\n"
-    "  if ($name$_ == &$default_variable$) {\n"
+    "  if ($name$_ == $default_variable$) {\n"
     "    $name$_ = new ::std::string;\n"
     "  }\n"
     "  $name$_->assign(value);\n"
@@ -141,20 +147,20 @@ GenerateInlineAccessorDefinitions(io::Printer* printer) const {
     "inline "
     "void $classname$::set_$name$(const $pointer_type$* value, size_t size) {\n"
     "  set_has_$name$();\n"
-    "  if ($name$_ == &$default_variable$) {\n"
+    "  if ($name$_ == $default_variable$) {\n"
     "    $name$_ = new ::std::string;\n"
     "  }\n"
     "  $name$_->assign(reinterpret_cast<const char*>(value), size);\n"
     "}\n"
     "inline ::std::string* $classname$::mutable_$name$() {\n"
     "  set_has_$name$();\n"
-    "  if ($name$_ == &$default_variable$) {\n");
+    "  if ($name$_ == $default_variable$) {\n");
   if (descriptor_->default_value_string().empty()) {
     printer->Print(variables_,
       "    $name$_ = new ::std::string;\n");
   } else {
     printer->Print(variables_,
-      "    $name$_ = new ::std::string($default_variable$);\n");
+      "    $name$_ = new ::std::string(*$default_variable$);\n");
   }
   printer->Print(variables_,
     "  }\n"
@@ -162,21 +168,34 @@ GenerateInlineAccessorDefinitions(io::Printer* printer) const {
     "}\n"
     "inline ::std::string* $classname$::release_$name$() {\n"
     "  clear_has_$name$();\n"
-    "  if ($name$_ == &$default_variable$) {\n"
+    "  if ($name$_ == $default_variable$) {\n"
     "    return NULL;\n"
     "  } else {\n"
     "    ::std::string* temp = $name$_;\n"
-    "    $name$_ = const_cast< ::std::string*>(&$default_variable$);\n"
+    "    $name$_ = const_cast< ::std::string*>($default_variable$);\n"
     "    return temp;\n"
     "  }\n"
+    "}\n"
+    "inline void $classname$::set_allocated_$name$(::std::string* $name$) {\n"
+    "  if ($name$_ != $default_variable$) {\n"
+    "    delete $name$_;\n"
+    "  }\n"
+    "  if ($name$) {\n"
+    "    set_has_$name$();\n"
+    "    $name$_ = $name$;\n"
+    "  } else {\n"
+    "    clear_has_$name$();\n"
+    "    $name$_ = const_cast< ::std::string*>($default_variable$);\n"
+    "  }\n"
     "}\n");
 }
 
 void StringFieldGenerator::
 GenerateNonInlineAccessorDefinitions(io::Printer* printer) const {
   if (!descriptor_->default_value_string().empty()) {
+    // Initialized in GenerateDefaultInstanceAllocator.
     printer->Print(variables_,
-      "const ::std::string $classname$::$default_variable$($default$);\n");
+      "::std::string* $classname$::$default_variable$ = NULL;\n");
   }
 }
 
@@ -184,13 +203,13 @@ void StringFieldGenerator::
 GenerateClearingCode(io::Printer* printer) const {
   if (descriptor_->default_value_string().empty()) {
     printer->Print(variables_,
-      "if ($name$_ != &$default_variable$) {\n"
+      "if ($name$_ != $default_variable$) {\n"
       "  $name$_->clear();\n"
       "}\n");
   } else {
     printer->Print(variables_,
-      "if ($name$_ != &$default_variable$) {\n"
-      "  $name$_->assign($default_variable$);\n"
+      "if ($name$_ != $default_variable$) {\n"
+      "  $name$_->assign(*$default_variable$);\n"
       "}\n");
   }
 }
@@ -208,18 +227,35 @@ GenerateSwappingCode(io::Printer* printer) const {
 void StringFieldGenerator::
 GenerateConstructorCode(io::Printer* printer) const {
   printer->Print(variables_,
-    "$name$_ = const_cast< ::std::string*>(&$default_variable$);\n");
+    "$name$_ = const_cast< ::std::string*>($default_variable$);\n");
 }
 
 void StringFieldGenerator::
 GenerateDestructorCode(io::Printer* printer) const {
   printer->Print(variables_,
-    "if ($name$_ != &$default_variable$) {\n"
+    "if ($name$_ != $default_variable$) {\n"
     "  delete $name$_;\n"
     "}\n");
 }
 
 void StringFieldGenerator::
+GenerateDefaultInstanceAllocator(io::Printer* printer) const {
+  if (!descriptor_->default_value_string().empty()) {
+    printer->Print(variables_,
+      "$classname$::$default_variable$ =\n"
+      "    new ::std::string($default$, $default_length$);\n");
+  }
+}
+
+void StringFieldGenerator::
+GenerateShutdownCode(io::Printer* printer) const {
+  if (!descriptor_->default_value_string().empty()) {
+    printer->Print(variables_,
+      "delete $classname$::$default_variable$;\n");
+  }
+}
+
+void StringFieldGenerator::
 GenerateMergeFromCodedStream(io::Printer* printer) const {
   printer->Print(variables_,
     "DO_(::google::protobuf::internal::WireFormatLite::Read$declared_type$(\n"
@@ -273,9 +309,10 @@ GenerateByteSize(io::Printer* printer) const {
 // ===================================================================
 
 RepeatedStringFieldGenerator::
-RepeatedStringFieldGenerator(const FieldDescriptor* descriptor)
+RepeatedStringFieldGenerator(const FieldDescriptor* descriptor,
+                             const Options& options)
   : descriptor_(descriptor) {
-  SetStringVariables(descriptor, &variables_);
+  SetStringVariables(descriptor, &variables_, options);
 }
 
 RepeatedStringFieldGenerator::~RepeatedStringFieldGenerator() {}
@@ -328,7 +365,7 @@ void RepeatedStringFieldGenerator::
 GenerateInlineAccessorDefinitions(io::Printer* printer) const {
   printer->Print(variables_,
     "inline const ::std::string& $classname$::$name$(int index) const {\n"
-    "  return $name$_.Get(index);\n"
+    "  return $name$_.$cppget$(index);\n"
     "}\n"
     "inline ::std::string* $classname$::mutable_$name$(int index) {\n"
     "  return $name$_.Mutable(index);\n"
diff --git a/src/google/protobuf/compiler/cpp/cpp_string_field.h b/src/google/protobuf/compiler/cpp/cpp_string_field.h
index 7f45107d..3264134a 100644
--- a/src/google/protobuf/compiler/cpp/cpp_string_field.h
+++ b/src/google/protobuf/compiler/cpp/cpp_string_field.h
@@ -46,7 +46,8 @@ namespace cpp {
 
 class StringFieldGenerator : public FieldGenerator {
  public:
-  explicit StringFieldGenerator(const FieldDescriptor* descriptor);
+  explicit StringFieldGenerator(const FieldDescriptor* descriptor,
+                                const Options& options);
   ~StringFieldGenerator();
 
   // implements FieldGenerator ---------------------------------------
@@ -59,6 +60,8 @@ class StringFieldGenerator : public FieldGenerator {
   void GenerateSwappingCode(io::Printer* printer) const;
   void GenerateConstructorCode(io::Printer* printer) const;
   void GenerateDestructorCode(io::Printer* printer) const;
+  void GenerateDefaultInstanceAllocator(io::Printer* printer) const;
+  void GenerateShutdownCode(io::Printer* printer) const;
   void GenerateMergeFromCodedStream(io::Printer* printer) const;
   void GenerateSerializeWithCachedSizes(io::Printer* printer) const;
   void GenerateSerializeWithCachedSizesToArray(io::Printer* printer) const;
@@ -73,7 +76,8 @@ class StringFieldGenerator : public FieldGenerator {
 
 class RepeatedStringFieldGenerator : public FieldGenerator {
  public:
-  explicit RepeatedStringFieldGenerator(const FieldDescriptor* descriptor);
+  explicit RepeatedStringFieldGenerator(const FieldDescriptor* descriptor,
+                                        const Options& options);
   ~RepeatedStringFieldGenerator();
 
   // implements FieldGenerator ---------------------------------------
diff --git a/src/google/protobuf/compiler/cpp/cpp_test_bad_identifiers.proto b/src/google/protobuf/compiler/cpp/cpp_test_bad_identifiers.proto
index 54d830fc..e14a818c 100644
--- a/src/google/protobuf/compiler/cpp/cpp_test_bad_identifiers.proto
+++ b/src/google/protobuf/compiler/cpp/cpp_test_bad_identifiers.proto
@@ -103,9 +103,19 @@ message TestConflictingSymbolNames {
   message DO {}
   optional DO do = 32;
 
+  // Some template parameter names for extensions.
+  optional int32 field_type = 33;
+  optional bool is_packed = 34;
+
   extensions 1000 to max;
 }
 
+message TestConflictingSymbolNamesExtension {
+  extend TestConflictingSymbolNames {
+    repeated int32 repeated_int32_ext = 20423638 [packed=true];
+  }
+}
+
 message DummyMessage {}
 
 service TestConflictingMethodNames {
diff --git a/src/google/protobuf/compiler/cpp/cpp_unittest.cc b/src/google/protobuf/compiler/cpp/cpp_unittest.cc
index 301a7ce6..b5f9ab58 100644
--- a/src/google/protobuf/compiler/cpp/cpp_unittest.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_unittest.cc
@@ -44,6 +44,8 @@
 // correctly and produces the interfaces we expect, which is why this test
 // is written this way.
 
+#include <google/protobuf/compiler/cpp/cpp_unittest.h>
+
 #include <vector>
 
 #include <google/protobuf/unittest.pb.h>
@@ -64,7 +66,7 @@
 #include <google/protobuf/stubs/substitute.h>
 #include <google/protobuf/testing/googletest.h>
 #include <gtest/gtest.h>
-#include <google/protobuf/stubs/stl_util-inl.h>
+#include <google/protobuf/stubs/stl_util.h>
 
 namespace google {
 namespace protobuf {
@@ -74,6 +76,8 @@ namespace cpp {
 // Can't use an anonymous namespace here due to brokenness of Tru64 compiler.
 namespace cpp_unittest {
 
+namespace protobuf_unittest = ::protobuf_unittest;
+
 
 class MockErrorCollector : public MultiFileErrorCollector {
  public:
@@ -174,6 +178,15 @@ TEST(GeneratedMessageTest, Trigraph) {
   EXPECT_EQ("? ? ?? ?? ??? ?\?/ ?\?-", extreme_default.cpp_trigraph());
 }
 
+TEST(GeneratedMessageTest, ExtremeSmallIntegerDefault) {
+  const unittest::TestExtremeDefaultValues& extreme_default =
+      unittest::TestExtremeDefaultValues::default_instance();
+  EXPECT_EQ(-0x80000000, kint32min);
+  EXPECT_EQ(GOOGLE_LONGLONG(-0x8000000000000000), kint64min);
+  EXPECT_EQ(kint32min, extreme_default.really_small_int32());
+  EXPECT_EQ(kint64min, extreme_default.really_small_int64());
+}
+
 TEST(GeneratedMessageTest, Accessors) {
   // Set every field to a unique value then go back and check all those
   // values.
@@ -202,6 +215,13 @@ TEST(GeneratedMessageTest, MutableStringDefault) {
   EXPECT_EQ("hello", *message.mutable_default_string());
 }
 
+TEST(GeneratedMessageTest, StringDefaults) {
+  unittest::TestExtremeDefaultValues message;
+  // Check if '\000' can be used in default string value.
+  EXPECT_EQ(string("hel\000lo", 6), message.string_with_zero());
+  EXPECT_EQ(string("wor\000ld", 6), message.bytes_with_zero());
+}
+
 TEST(GeneratedMessageTest, ReleaseString) {
   // Check that release_foo() starts out NULL, and gives us a value
   // that we can delete after it's been set.
@@ -244,6 +264,49 @@ TEST(GeneratedMessageTest, ReleaseMessage) {
   EXPECT_FALSE(message.has_optional_nested_message());
 }
 
+TEST(GeneratedMessageTest, SetAllocatedString) {
+  // Check that set_allocated_foo() works for strings.
+  unittest::TestAllTypes message;
+
+  EXPECT_FALSE(message.has_optional_string());
+  const string kHello("hello");
+  message.set_optional_string(kHello);
+  EXPECT_TRUE(message.has_optional_string());
+
+  message.set_allocated_optional_string(NULL);
+  EXPECT_FALSE(message.has_optional_string());
+  EXPECT_EQ("", message.optional_string());
+
+  message.set_allocated_optional_string(new string(kHello));
+  EXPECT_TRUE(message.has_optional_string());
+  EXPECT_EQ(kHello, message.optional_string());
+}
+
+TEST(GeneratedMessageTest, SetAllocatedMessage) {
+  // Check that set_allocated_foo() can be called in all cases.
+  unittest::TestAllTypes message;
+
+  EXPECT_FALSE(message.has_optional_nested_message());
+
+  message.mutable_optional_nested_message()->set_bb(1);
+  EXPECT_TRUE(message.has_optional_nested_message());
+
+  message.set_allocated_optional_nested_message(NULL);
+  EXPECT_FALSE(message.has_optional_nested_message());
+  EXPECT_EQ(&unittest::TestAllTypes::NestedMessage::default_instance(),
+            &message.optional_nested_message());
+
+  message.mutable_optional_nested_message()->set_bb(1);
+  unittest::TestAllTypes::NestedMessage* nest =
+      message.release_optional_nested_message();
+  ASSERT_TRUE(nest != NULL);
+  EXPECT_FALSE(message.has_optional_nested_message());
+
+  message.set_allocated_optional_nested_message(nest);
+  EXPECT_TRUE(message.has_optional_nested_message());
+  EXPECT_EQ(1, message.optional_nested_message().bb());
+}
+
 TEST(GeneratedMessageTest, Clear) {
   // Set every field to a unique value, clear the message, then check that
   // it is cleared.
@@ -695,6 +758,13 @@ TEST(GeneratedMessageTest, TestConflictingSymbolNames) {
 
   message.set_friend_(5);
   EXPECT_EQ(5, message.friend_());
+
+  // Instantiate extension template functions to test conflicting template
+  // parameter names.
+  typedef protobuf_unittest::TestConflictingSymbolNamesExtension ExtensionMessage;
+  message.AddExtension(ExtensionMessage::repeated_int32_ext, 123);
+  EXPECT_EQ(123,
+            message.GetExtension(ExtensionMessage::repeated_int32_ext, 0));
 }
 
 #ifndef PROTOBUF_TEST_NO_DESCRIPTORS
@@ -869,11 +939,10 @@ TEST(GeneratedEnumTest, MinAndMax) {
   EXPECT_NE(null_pointer, &unittest::ForeignEnum_MAX);
   EXPECT_NE(null_pointer, &unittest::ForeignEnum_ARRAYSIZE);
 
-  // Make sure we can use _MIN, _MAX and _ARRAYSIZE as switch cases.
+  // Make sure we can use _MIN and _MAX as switch cases.
   switch (unittest::SPARSE_A) {
     case unittest::TestSparseEnum_MIN:
     case unittest::TestSparseEnum_MAX:
-    case unittest::TestSparseEnum_ARRAYSIZE:
       break;
     default:
       break;
diff --git a/src/google/protobuf/compiler/cpp/cpp_unittest.h b/src/google/protobuf/compiler/cpp/cpp_unittest.h
new file mode 100644
index 00000000..a3a1d1ba
--- /dev/null
+++ b/src/google/protobuf/compiler/cpp/cpp_unittest.h
@@ -0,0 +1,51 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// 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.
+
+// This header declares the namespace google::protobuf::protobuf_unittest in order to expose
+// any problems with the generated class names. We use this header to ensure
+// unittest.cc will declare the namespace prior to other includes, while obeying
+// normal include ordering.
+//
+// When generating a class name of "foo.Bar" we must ensure we prefix the class
+// name with "::", in case the namespace google::protobuf::foo exists. We intentionally
+// trigger that case here by declaring google::protobuf::protobuf_unittest.
+//
+// See ClassName in helpers.h for more details.
+
+#ifndef GOOGLE_PROTOBUF_COMPILER_CPP_UNITTEST_H__
+#define GOOGLE_PROTOBUF_COMPILER_CPP_UNITTEST_H__
+
+namespace google {
+namespace protobuf {
+namespace protobuf_unittest {}
+}  // namespace protobuf
+
+}  // namespace google
+#endif  // GOOGLE_PROTOBUF_COMPILER_CPP_UNITTEST_H__
diff --git a/src/google/protobuf/compiler/importer.h b/src/google/protobuf/compiler/importer.h
index 7a2efc29..7a62fa0e 100644
--- a/src/google/protobuf/compiler/importer.h
+++ b/src/google/protobuf/compiler/importer.h
@@ -280,8 +280,9 @@ class LIBPROTOBUF_EXPORT DiskSourceTree : public SourceTree {
     string virtual_path;
     string disk_path;
 
-    inline Mapping(const string& virtual_path, const string& disk_path)
-      : virtual_path(virtual_path), disk_path(disk_path) {}
+    inline Mapping(const string& virtual_path_param,
+                   const string& disk_path_param)
+      : virtual_path(virtual_path_param), disk_path(disk_path_param) {}
   };
   vector<Mapping> mappings_;
 
diff --git a/src/google/protobuf/compiler/java/java_doc_comment.cc b/src/google/protobuf/compiler/java/java_doc_comment.cc
new file mode 100644
index 00000000..60b4f2ac
--- /dev/null
+++ b/src/google/protobuf/compiler/java/java_doc_comment.cc
@@ -0,0 +1,236 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// 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: kenton@google.com (Kenton Varda)
+//  Based on original Protocol Buffers design by
+//  Sanjay Ghemawat, Jeff Dean, and others.
+
+#include <google/protobuf/compiler/java/java_doc_comment.h>
+
+#include <vector>
+
+#include <google/protobuf/io/printer.h>
+#include <google/protobuf/stubs/strutil.h>
+
+namespace google {
+namespace protobuf {
+namespace compiler {
+namespace java {
+
+string EscapeJavadoc(const string& input) {
+  string result;
+  result.reserve(input.size() * 2);
+
+  char prev = '*';
+
+  for (string::size_type i = 0; i < input.size(); i++) {
+    char c = input[i];
+    switch (c) {
+      case '*':
+        // Avoid "/*".
+        if (prev == '/') {
+          result.append("&#42;");
+        } else {
+          result.push_back(c);
+        }
+        break;
+      case '/':
+        // Avoid "*/".
+        if (prev == '*') {
+          result.append("&#47;");
+        } else {
+          result.push_back(c);
+        }
+        break;
+      case '@':
+        // "{@" starts Javadoc markup.
+        if (prev == '{') {
+          result.append("&#64;");
+        } else {
+          result.push_back(c);
+        }
+        break;
+      case '<':
+        // Avoid interpretation as HTML.
+        result.append("&lt;");
+        break;
+      case '>':
+        // Avoid interpretation as HTML.
+        result.append("&gt;");
+        break;
+      case '&':
+        // Avoid interpretation as HTML.
+        result.append("&amp;");
+        break;
+      case '\\':
+        // Java interprets Unicode escape sequences anywhere!
+        result.append("&#92;");
+        break;
+      default:
+        result.push_back(c);
+        break;
+    }
+
+    prev = c;
+  }
+
+  return result;
+}
+
+static void WriteDocCommentBodyForLocation(
+    io::Printer* printer, const SourceLocation& location) {
+  string comments = location.leading_comments.empty() ?
+      location.trailing_comments : location.leading_comments;
+  if (!comments.empty()) {
+    // TODO(kenton):  Ideally we should parse the comment text as Markdown and
+    //   write it back as HTML, but this requires a Markdown parser.  For now
+    //   we just use <pre> to get fixed-width text formatting.
+
+    // If the comment itself contains block comment start or end markers,
+    // HTML-escape them so that they don't accidentally close the doc comment.
+    comments = EscapeJavadoc(comments);
+
+    vector<string> lines;
+    SplitStringAllowEmpty(comments, "\n", &lines);
+    while (!lines.empty() && lines.back().empty()) {
+      lines.pop_back();
+    }
+
+    printer->Print(
+        " *\n"
+        " * <pre>\n");
+    for (int i = 0; i < lines.size(); i++) {
+      // Most lines should start with a space.  Watch out for lines that start
+      // with a /, since putting that right after the leading asterisk will
+      // close the comment.
+      if (!lines[i].empty() && lines[i][0] == '/') {
+        printer->Print(" * $line$\n", "line", lines[i]);
+      } else {
+        printer->Print(" *$line$\n", "line", lines[i]);
+      }
+    }
+    printer->Print(" * </pre>\n");
+  }
+}
+
+template <typename DescriptorType>
+static void WriteDocCommentBody(
+    io::Printer* printer, const DescriptorType* descriptor) {
+  SourceLocation location;
+  if (descriptor->GetSourceLocation(&location)) {
+    WriteDocCommentBodyForLocation(printer, location);
+  }
+}
+
+static string FirstLineOf(const string& value) {
+  string result = value;
+
+  string::size_type pos = result.find_first_of('\n');
+  if (pos != string::npos) {
+    result.erase(pos);
+  }
+
+  // If line ends in an opening brace, make it "{ ... }" so it looks nice.
+  if (!result.empty() && result[result.size() - 1] == '{') {
+    result.append(" ... }");
+  }
+
+  return result;
+}
+
+void WriteMessageDocComment(io::Printer* printer, const Descriptor* message) {
+  printer->Print(
+    "/**\n"
+    " * Protobuf type {@code $fullname$}\n",
+    "fullname", EscapeJavadoc(message->full_name()));
+  WriteDocCommentBody(printer, message);
+  printer->Print(" */\n");
+}
+
+void WriteFieldDocComment(io::Printer* printer, const FieldDescriptor* field) {
+  // In theory we should have slightly different comments for setters, getters,
+  // etc., but in practice everyone already knows the difference between these
+  // so it's redundant information.
+
+  // We use the field declaration as the first line of the comment, e.g.:
+  //   optional string foo = 5;
+  // This communicates a lot of information about the field in a small space.
+  // If the field is a group, the debug string might end with {.
+  printer->Print(
+    "/**\n"
+    " * <code>$def$</code>\n",
+    "def", EscapeJavadoc(FirstLineOf(field->DebugString())));
+  WriteDocCommentBody(printer, field);
+  printer->Print(" */\n");
+}
+
+void WriteEnumDocComment(io::Printer* printer, const EnumDescriptor* enum_) {
+  printer->Print(
+    "/**\n"
+    " * Protobuf enum {@code $fullname$}\n",
+    "fullname", EscapeJavadoc(enum_->full_name()));
+  WriteDocCommentBody(printer, enum_);
+  printer->Print(" */\n");
+}
+
+void WriteEnumValueDocComment(io::Printer* printer,
+                              const EnumValueDescriptor* value) {
+  printer->Print(
+    "/**\n"
+    " * <code>$def$</code>\n",
+    "def", EscapeJavadoc(FirstLineOf(value->DebugString())));
+  WriteDocCommentBody(printer, value);
+  printer->Print(" */\n");
+}
+
+void WriteServiceDocComment(io::Printer* printer,
+                            const ServiceDescriptor* service) {
+  printer->Print(
+    "/**\n"
+    " * Protobuf service {@code $fullname$}\n",
+    "fullname", EscapeJavadoc(service->full_name()));
+  WriteDocCommentBody(printer, service);
+  printer->Print(" */\n");
+}
+
+void WriteMethodDocComment(io::Printer* printer,
+                           const MethodDescriptor* method) {
+  printer->Print(
+    "/**\n"
+    " * <code>$def$</code>\n",
+    "def", EscapeJavadoc(FirstLineOf(method->DebugString())));
+  WriteDocCommentBody(printer, method);
+  printer->Print(" */\n");
+}
+
+}  // namespace java
+}  // namespace compiler
+}  // namespace protobuf
+}  // namespace google
diff --git a/src/google/protobuf/compiler/java/java_doc_comment.h b/src/google/protobuf/compiler/java/java_doc_comment.h
new file mode 100644
index 00000000..f77720b6
--- /dev/null
+++ b/src/google/protobuf/compiler/java/java_doc_comment.h
@@ -0,0 +1,69 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// 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: kenton@google.com (Kenton Varda)
+//  Based on original Protocol Buffers design by
+//  Sanjay Ghemawat, Jeff Dean, and others.
+
+#ifndef GOOGLE_PROTOBUF_COMPILER_JAVA_DOC_COMMENT_H__
+#define GOOGLE_PROTOBUF_COMPILER_JAVA_DOC_COMMENT_H__
+
+#include <google/protobuf/descriptor.h>
+
+namespace google {
+namespace protobuf {
+  namespace io {
+    class Printer;             // printer.h
+  }
+}
+
+namespace protobuf {
+namespace compiler {
+namespace java {
+
+void WriteMessageDocComment(io::Printer* printer, const Descriptor* message);
+void WriteFieldDocComment(io::Printer* printer, const FieldDescriptor* field);
+void WriteEnumDocComment(io::Printer* printer, const EnumDescriptor* enum_);
+void WriteEnumValueDocComment(io::Printer* printer,
+                              const EnumValueDescriptor* value);
+void WriteServiceDocComment(io::Printer* printer,
+                            const ServiceDescriptor* service);
+void WriteMethodDocComment(io::Printer* printer,
+                           const MethodDescriptor* method);
+
+// Exposed for testing only.
+string EscapeJavadoc(const string& input);
+
+}  // namespace java
+}  // namespace compiler
+}  // namespace protobuf
+
+}  // namespace google
+#endif  // GOOGLE_PROTOBUF_COMPILER_JAVA_DOC_COMMENT_H__
diff --git a/src/google/protobuf/compiler/java/java_doc_comment_unittest.cc b/src/google/protobuf/compiler/java/java_doc_comment_unittest.cc
new file mode 100644
index 00000000..28b6d8b4
--- /dev/null
+++ b/src/google/protobuf/compiler/java/java_doc_comment_unittest.cc
@@ -0,0 +1,66 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// 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: kenton@google.com (Kenton Varda)
+
+#include <google/protobuf/compiler/java/java_doc_comment.h>
+
+#include <gtest/gtest.h>
+
+namespace google {
+namespace protobuf {
+namespace compiler {
+namespace java {
+namespace {
+
+TEST(JavaDocCommentTest, Escaping) {
+  EXPECT_EQ("foo /&#42; bar *&#47; baz", EscapeJavadoc("foo /* bar */ baz"));
+  EXPECT_EQ("foo /&#42;&#47; baz", EscapeJavadoc("foo /*/ baz"));
+  EXPECT_EQ("{&#64;foo}", EscapeJavadoc("{@foo}"));
+  EXPECT_EQ("&lt;i&gt;&amp;&lt;/i&gt;", EscapeJavadoc("<i>&</i>"));
+  EXPECT_EQ("foo&#92;u1234bar", EscapeJavadoc("foo\\u1234bar"));
+}
+
+// TODO(kenton):  It's hard to write a robust test of the doc comments -- we
+//   can only really compare the output against a golden value, which is a
+//   fairly tedious and fragile testing strategy.  If we want to go that route,
+//   it probably makes sense to bite the bullet and write a test that compares
+//   the whole generated output for unittest.proto against a golden value, with
+//   a very simple script that can be run to regenerate it with the latest code.
+//   This would mean that updates to the golden file would have to be included
+//   in any change to the code generator, which would actually be fairly useful
+//   as it allows the reviewer to see clearly how the generated code is
+//   changing.
+
+}  // namespace
+}  // namespace java
+}  // namespace compiler
+}  // namespace protobuf
+}  // namespace google
diff --git a/src/google/protobuf/compiler/java/java_enum.cc b/src/google/protobuf/compiler/java/java_enum.cc
index 9d7bcab6..cfed815f 100644
--- a/src/google/protobuf/compiler/java/java_enum.cc
+++ b/src/google/protobuf/compiler/java/java_enum.cc
@@ -36,6 +36,7 @@
 #include <string>
 
 #include <google/protobuf/compiler/java/java_enum.h>
+#include <google/protobuf/compiler/java/java_doc_comment.h>
 #include <google/protobuf/compiler/java/java_helpers.h>
 #include <google/protobuf/io/printer.h>
 #include <google/protobuf/descriptor.pb.h>
@@ -67,6 +68,7 @@ EnumGenerator::EnumGenerator(const EnumDescriptor* descriptor)
 EnumGenerator::~EnumGenerator() {}
 
 void EnumGenerator::Generate(io::Printer* printer) {
+  WriteEnumDocComment(printer, descriptor_);
   if (HasDescriptorMethods(descriptor_)) {
     printer->Print(
       "public enum $classname$\n"
@@ -85,6 +87,7 @@ void EnumGenerator::Generate(io::Printer* printer) {
     vars["name"] = canonical_values_[i]->name();
     vars["index"] = SimpleItoa(canonical_values_[i]->index());
     vars["number"] = SimpleItoa(canonical_values_[i]->number());
+    WriteEnumValueDocComment(printer, canonical_values_[i]);
     printer->Print(vars,
       "$name$($index$, $number$),\n");
   }
@@ -100,6 +103,7 @@ void EnumGenerator::Generate(io::Printer* printer) {
     vars["classname"] = descriptor_->name();
     vars["name"] = aliases_[i].value->name();
     vars["canonical_name"] = aliases_[i].canonical_value->name();
+    WriteEnumValueDocComment(printer, aliases_[i].value);
     printer->Print(vars,
       "public static final $classname$ $name$ = $canonical_name$;\n");
   }
@@ -108,6 +112,7 @@ void EnumGenerator::Generate(io::Printer* printer) {
     map<string, string> vars;
     vars["name"] = descriptor_->value(i)->name();
     vars["number"] = SimpleItoa(descriptor_->value(i)->number());
+    WriteEnumValueDocComment(printer, descriptor_->value(i));
     printer->Print(vars,
       "public static final int $name$_VALUE = $number$;\n");
   }
@@ -187,19 +192,30 @@ void EnumGenerator::Generate(io::Printer* printer) {
     printer->Print(
       "}\n"
       "\n"
-      "private static final $classname$[] VALUES = {\n"
-      "  ",
+      "private static final $classname$[] VALUES = ",
       "classname", descriptor_->name());
 
-    for (int i = 0; i < descriptor_->value_count(); i++) {
-      printer->Print("$name$, ",
-        "name", descriptor_->value(i)->name());
+    if (CanUseEnumValues()) {
+      // If the constants we are going to output are exactly the ones we
+      // have declared in the Java enum in the same order, then we can use
+      // the values() method that the Java compiler automatically generates
+      // for every enum.
+      printer->Print("values();\n");
+    } else {
+      printer->Print(
+        "{\n"
+        "  ");
+      for (int i = 0; i < descriptor_->value_count(); i++) {
+        printer->Print("$name$, ",
+          "name", descriptor_->value(i)->name());
+      }
+      printer->Print(
+          "\n"
+          "};\n");
     }
 
     printer->Print(
       "\n"
-      "};\n"
-      "\n"
       "public static $classname$ valueOf(\n"
       "    com.google.protobuf.Descriptors.EnumValueDescriptor desc) {\n"
       "  if (desc.getType() != getDescriptor()) {\n"
@@ -237,6 +253,18 @@ void EnumGenerator::Generate(io::Printer* printer) {
   printer->Print("}\n\n");
 }
 
+bool EnumGenerator::CanUseEnumValues() {
+  if (canonical_values_.size() != descriptor_->value_count()) {
+    return false;
+  }
+  for (int i = 0; i < descriptor_->value_count(); i++) {
+    if (descriptor_->value(i)->name() != canonical_values_[i]->name()) {
+      return false;
+    }
+  }
+  return true;
+}
+
 }  // namespace java
 }  // namespace compiler
 }  // namespace protobuf
diff --git a/src/google/protobuf/compiler/java/java_enum.h b/src/google/protobuf/compiler/java/java_enum.h
index 05ece1f1..9a9e5742 100644
--- a/src/google/protobuf/compiler/java/java_enum.h
+++ b/src/google/protobuf/compiler/java/java_enum.h
@@ -73,6 +73,8 @@ class EnumGenerator {
   };
   vector<Alias> aliases_;
 
+  bool CanUseEnumValues();
+
   GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(EnumGenerator);
 };
 
diff --git a/src/google/protobuf/compiler/java/java_enum_field.cc b/src/google/protobuf/compiler/java/java_enum_field.cc
index 72caa10b..ec0b067e 100644
--- a/src/google/protobuf/compiler/java/java_enum_field.cc
+++ b/src/google/protobuf/compiler/java/java_enum_field.cc
@@ -36,6 +36,7 @@
 #include <string>
 
 #include <google/protobuf/compiler/java/java_enum_field.h>
+#include <google/protobuf/compiler/java/java_doc_comment.h>
 #include <google/protobuf/stubs/common.h>
 #include <google/protobuf/compiler/java/java_helpers.h>
 #include <google/protobuf/io/printer.h>
@@ -75,6 +76,7 @@ void SetEnumVariables(const FieldDescriptor* descriptor,
 
   // For singular messages and builders, one bit is used for the hasField bit.
   (*variables)["get_has_field_bit_message"] = GenerateGetBit(messageBitIndex);
+  (*variables)["set_has_field_bit_message"] = GenerateSetBit(messageBitIndex);
 
   (*variables)["get_has_field_bit_builder"] = GenerateGetBit(builderBitIndex);
   (*variables)["set_has_field_bit_builder"] = GenerateSetBit(builderBitIndex);
@@ -86,6 +88,13 @@ void SetEnumVariables(const FieldDescriptor* descriptor,
   (*variables)["set_mutable_bit_builder"] = GenerateSetBit(builderBitIndex);
   (*variables)["clear_mutable_bit_builder"] = GenerateClearBit(builderBitIndex);
 
+  // For repeated fields, one bit is used for whether the array is immutable
+  // in the parsing constructor.
+  (*variables)["get_mutable_bit_parser"] =
+      GenerateGetBitMutableLocal(builderBitIndex);
+  (*variables)["set_mutable_bit_parser"] =
+      GenerateSetBitMutableLocal(builderBitIndex);
+
   (*variables)["get_has_field_bit_from_local"] =
       GenerateGetBitFromLocal(builderBitIndex);
   (*variables)["set_has_field_bit_to_local"] =
@@ -117,18 +126,25 @@ int EnumFieldGenerator::GetNumBitsForBuilder() const {
 
 void EnumFieldGenerator::
 GenerateInterfaceMembers(io::Printer* printer) const {
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
+    "$deprecation$boolean has$capitalized_name$();\n");
+  WriteFieldDocComment(printer, descriptor_);
   printer->Print(variables_,
-    "$deprecation$boolean has$capitalized_name$();\n"
     "$deprecation$$type$ get$capitalized_name$();\n");
 }
 
 void EnumFieldGenerator::
 GenerateMembers(io::Printer* printer) const {
   printer->Print(variables_,
-    "private $type$ $name$_;\n"
+    "private $type$ $name$_;\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public boolean has$capitalized_name$() {\n"
     "  return $get_has_field_bit_message$;\n"
-    "}\n"
+    "}\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public $type$ get$capitalized_name$() {\n"
     "  return $name$_;\n"
     "}\n");
@@ -137,13 +153,19 @@ GenerateMembers(io::Printer* printer) const {
 void EnumFieldGenerator::
 GenerateBuilderMembers(io::Printer* printer) const {
   printer->Print(variables_,
-    "private $type$ $name$_ = $default$;\n"
+    "private $type$ $name$_ = $default$;\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public boolean has$capitalized_name$() {\n"
     "  return $get_has_field_bit_builder$;\n"
-    "}\n"
+    "}\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public $type$ get$capitalized_name$() {\n"
     "  return $name$_;\n"
-    "}\n"
+    "}\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public Builder set$capitalized_name$($type$ value) {\n"
     "  if (value == null) {\n"
     "    throw new NullPointerException();\n"
@@ -152,7 +174,9 @@ GenerateBuilderMembers(io::Printer* printer) const {
     "  $name$_ = value;\n"
     "  $on_changed$\n"
     "  return this;\n"
-    "}\n"
+    "}\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public Builder clear$capitalized_name$() {\n"
     "  $clear_has_field_bit_builder$;\n"
     "  $name$_ = $default$;\n"
@@ -210,12 +234,17 @@ GenerateParsingCode(io::Printer* printer) const {
       "if (value != null) {\n");
   }
   printer->Print(variables_,
-    "  $set_has_field_bit_builder$;\n"
+    "  $set_has_field_bit_message$;\n"
     "  $name$_ = value;\n"
     "}\n");
 }
 
 void EnumFieldGenerator::
+GenerateParsingDoneCode(io::Printer* printer) const {
+  // noop for enums
+}
+
+void EnumFieldGenerator::
 GenerateSerializationCode(io::Printer* printer) const {
   printer->Print(variables_,
     "if ($get_has_field_bit_message$) {\n"
@@ -273,22 +302,33 @@ int RepeatedEnumFieldGenerator::GetNumBitsForBuilder() const {
 
 void RepeatedEnumFieldGenerator::
 GenerateInterfaceMembers(io::Printer* printer) const {
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
+    "$deprecation$java.util.List<$type$> get$capitalized_name$List();\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
+    "$deprecation$int get$capitalized_name$Count();\n");
+  WriteFieldDocComment(printer, descriptor_);
   printer->Print(variables_,
-    "$deprecation$java.util.List<$type$> get$capitalized_name$List();\n"
-    "$deprecation$int get$capitalized_name$Count();\n"
     "$deprecation$$type$ get$capitalized_name$(int index);\n");
 }
 
 void RepeatedEnumFieldGenerator::
 GenerateMembers(io::Printer* printer) const {
   printer->Print(variables_,
-    "private java.util.List<$type$> $name$_;\n"
+    "private java.util.List<$type$> $name$_;\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public java.util.List<$type$> get$capitalized_name$List() {\n"
     "  return $name$_;\n"   // note:  unmodifiable list
-    "}\n"
+    "}\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public int get$capitalized_name$Count() {\n"
     "  return $name$_.size();\n"
-    "}\n"
+    "}\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public $type$ get$capitalized_name$(int index) {\n"
     "  return $name$_.get(index);\n"
     "}\n");
@@ -320,21 +360,29 @@ GenerateBuilderMembers(io::Printer* printer) const {
     "    $name$_ = new java.util.ArrayList<$type$>($name$_);\n"
     "    $set_mutable_bit_builder$;\n"
     "  }\n"
-    "}\n"
+    "}\n");
 
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     // Note:  We return an unmodifiable list because otherwise the caller
     //   could hold on to the returned list and modify it after the message
     //   has been built, thus mutating the message which is supposed to be
     //   immutable.
     "$deprecation$public java.util.List<$type$> get$capitalized_name$List() {\n"
     "  return java.util.Collections.unmodifiableList($name$_);\n"
-    "}\n"
+    "}\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public int get$capitalized_name$Count() {\n"
     "  return $name$_.size();\n"
-    "}\n"
+    "}\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public $type$ get$capitalized_name$(int index) {\n"
     "  return $name$_.get(index);\n"
-    "}\n"
+    "}\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public Builder set$capitalized_name$(\n"
     "    int index, $type$ value) {\n"
     "  if (value == null) {\n"
@@ -344,7 +392,9 @@ GenerateBuilderMembers(io::Printer* printer) const {
     "  $name$_.set(index, value);\n"
     "  $on_changed$\n"
     "  return this;\n"
-    "}\n"
+    "}\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public Builder add$capitalized_name$($type$ value) {\n"
     "  if (value == null) {\n"
     "    throw new NullPointerException();\n"
@@ -353,14 +403,18 @@ GenerateBuilderMembers(io::Printer* printer) const {
     "  $name$_.add(value);\n"
     "  $on_changed$\n"
     "  return this;\n"
-    "}\n"
+    "}\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public Builder addAll$capitalized_name$(\n"
     "    java.lang.Iterable<? extends $type$> values) {\n"
     "  ensure$capitalized_name$IsMutable();\n"
     "  super.addAll(values, $name$_);\n"
     "  $on_changed$\n"
     "  return this;\n"
-    "}\n"
+    "}\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public Builder clear$capitalized_name$() {\n"
     "  $name$_ = java.util.Collections.emptyList();\n"
     "  $clear_mutable_bit_builder$;\n"
@@ -434,7 +488,11 @@ GenerateParsingCode(io::Printer* printer) const {
       "if (value != null) {\n");
   }
   printer->Print(variables_,
-    "  add$capitalized_name$(value);\n"
+    "  if (!$get_mutable_bit_parser$) {\n"
+    "    $name$_ = new java.util.ArrayList<$type$>();\n"
+    "    $set_mutable_bit_parser$;\n"
+    "  }\n"
+    "  $name$_.add(value);\n"
     "}\n");
 }
 
@@ -457,6 +515,14 @@ GenerateParsingCodeFromPacked(io::Printer* printer) const {
 }
 
 void RepeatedEnumFieldGenerator::
+GenerateParsingDoneCode(io::Printer* printer) const {
+  printer->Print(variables_,
+    "if ($get_mutable_bit_parser$) {\n"
+    "  $name$_ = java.util.Collections.unmodifiableList($name$_);\n"
+    "}\n");
+}
+
+void RepeatedEnumFieldGenerator::
 GenerateSerializationCode(io::Printer* printer) const {
   if (descriptor_->options().packed()) {
     printer->Print(variables_,
diff --git a/src/google/protobuf/compiler/java/java_enum_field.h b/src/google/protobuf/compiler/java/java_enum_field.h
index 0cad6be0..90fae639 100644
--- a/src/google/protobuf/compiler/java/java_enum_field.h
+++ b/src/google/protobuf/compiler/java/java_enum_field.h
@@ -61,6 +61,7 @@ class EnumFieldGenerator : public FieldGenerator {
   void GenerateMergingCode(io::Printer* printer) const;
   void GenerateBuildingCode(io::Printer* printer) const;
   void GenerateParsingCode(io::Printer* printer) const;
+  void GenerateParsingDoneCode(io::Printer* printer) const;
   void GenerateSerializationCode(io::Printer* printer) const;
   void GenerateSerializedSizeCode(io::Printer* printer) const;
   void GenerateFieldBuilderInitializationCode(io::Printer* printer) const;
@@ -96,6 +97,7 @@ class RepeatedEnumFieldGenerator : public FieldGenerator {
   void GenerateBuildingCode(io::Printer* printer) const;
   void GenerateParsingCode(io::Printer* printer) const;
   void GenerateParsingCodeFromPacked(io::Printer* printer) const;
+  void GenerateParsingDoneCode(io::Printer* printer) const;
   void GenerateSerializationCode(io::Printer* printer) const;
   void GenerateSerializedSizeCode(io::Printer* printer) const;
   void GenerateFieldBuilderInitializationCode(io::Printer* printer) const;
diff --git a/src/google/protobuf/compiler/java/java_extension.cc b/src/google/protobuf/compiler/java/java_extension.cc
index 9b147c77..921fe658 100644
--- a/src/google/protobuf/compiler/java/java_extension.cc
+++ b/src/google/protobuf/compiler/java/java_extension.cc
@@ -33,6 +33,7 @@
 //  Sanjay Ghemawat, Jeff Dean, and others.
 
 #include <google/protobuf/compiler/java/java_extension.h>
+#include <google/protobuf/compiler/java/java_doc_comment.h>
 #include <google/protobuf/compiler/java/java_helpers.h>
 #include <google/protobuf/stubs/strutil.h>
 #include <google/protobuf/io/printer.h>
@@ -130,6 +131,7 @@ void ExtensionGenerator::Generate(io::Printer* printer) {
   printer->Print(vars,
       "public static final int $constant_name$ = $number$;\n");
 
+  WriteFieldDocComment(printer, descriptor_);
   if (HasDescriptorMethods(descriptor_->file())) {
     // Non-lite extensions
     if (descriptor_->extension_scope() == NULL) {
diff --git a/src/google/protobuf/compiler/java/java_field.h b/src/google/protobuf/compiler/java/java_field.h
index 6097f357..4dd0efd6 100644
--- a/src/google/protobuf/compiler/java/java_field.h
+++ b/src/google/protobuf/compiler/java/java_field.h
@@ -66,6 +66,7 @@ class FieldGenerator {
   virtual void GenerateBuildingCode(io::Printer* printer) const = 0;
   virtual void GenerateParsingCode(io::Printer* printer) const = 0;
   virtual void GenerateParsingCodeFromPacked(io::Printer* printer) const;
+  virtual void GenerateParsingDoneCode(io::Printer* printer) const = 0;
   virtual void GenerateSerializationCode(io::Printer* printer) const = 0;
   virtual void GenerateSerializedSizeCode(io::Printer* printer) const = 0;
   virtual void GenerateFieldBuilderInitializationCode(io::Printer* printer)
diff --git a/src/google/protobuf/compiler/java/java_file.cc b/src/google/protobuf/compiler/java/java_file.cc
index 8968069f..f43e5500 100644
--- a/src/google/protobuf/compiler/java/java_file.cc
+++ b/src/google/protobuf/compiler/java/java_file.cc
@@ -42,6 +42,7 @@
 #include <google/protobuf/io/printer.h>
 #include <google/protobuf/io/zero_copy_stream.h>
 #include <google/protobuf/descriptor.pb.h>
+#include <google/protobuf/dynamic_message.h>
 #include <google/protobuf/stubs/strutil.h>
 
 namespace google {
@@ -51,18 +52,24 @@ namespace java {
 
 namespace {
 
-// Recursively searches the given message to see if it contains any extensions.
-bool UsesExtensions(const Message& message) {
+
+// Recursively searches the given message to collect extensions.
+// Returns true if all the extensions can be recognized. The extensions will be
+// appended in to the extensions parameter.
+// Returns false when there are unknown fields, in which case the data in the
+// extensions output parameter is not reliable and should be discarded.
+bool CollectExtensions(const Message& message,
+                       vector<const FieldDescriptor*>* extensions) {
   const Reflection* reflection = message.GetReflection();
 
-  // We conservatively assume that unknown fields are extensions.
-  if (reflection->GetUnknownFields(message).field_count() > 0) return true;
+  // There are unknown fields that could be extensions, thus this call fails.
+  if (reflection->GetUnknownFields(message).field_count() > 0) return false;
 
   vector<const FieldDescriptor*> fields;
   reflection->ListFields(message, &fields);
 
   for (int i = 0; i < fields.size(); i++) {
-    if (fields[i]->is_extension()) return true;
+    if (fields[i]->is_extension()) extensions->push_back(fields[i]);
 
     if (GetJavaType(fields[i]) == JAVATYPE_MESSAGE) {
       if (fields[i]->is_repeated()) {
@@ -70,16 +77,56 @@ bool UsesExtensions(const Message& message) {
         for (int j = 0; j < size; j++) {
           const Message& sub_message =
             reflection->GetRepeatedMessage(message, fields[i], j);
-          if (UsesExtensions(sub_message)) return true;
+          if (!CollectExtensions(sub_message, extensions)) return false;
         }
       } else {
         const Message& sub_message = reflection->GetMessage(message, fields[i]);
-        if (UsesExtensions(sub_message)) return true;
+        if (!CollectExtensions(sub_message, extensions)) return false;
       }
     }
   }
 
-  return false;
+  return true;
+}
+
+// Finds all extensions in the given message and its sub-messages.  If the
+// message contains unknown fields (which could be extensions), then those
+// extensions are defined in alternate_pool.
+// The message will be converted to a DynamicMessage backed by alternate_pool
+// in order to handle this case.
+void CollectExtensions(const FileDescriptorProto& file_proto,
+                       const DescriptorPool& alternate_pool,
+                       vector<const FieldDescriptor*>* extensions,
+                       const string& file_data) {
+  if (!CollectExtensions(file_proto, extensions)) {
+    // There are unknown fields in the file_proto, which are probably
+    // extensions. We need to parse the data into a dynamic message based on the
+    // builder-pool to find out all extensions.
+    const Descriptor* file_proto_desc = alternate_pool.FindMessageTypeByName(
+        file_proto.GetDescriptor()->full_name());
+    GOOGLE_CHECK(file_proto_desc)
+        << "Find unknown fields in FileDescriptorProto when building "
+        << file_proto.name()
+        << ". It's likely that those fields are custom options, however, "
+           "descriptor.proto is not in the transitive dependencies. "
+           "This normally should not happen. Please report a bug.";
+    DynamicMessageFactory factory;
+    scoped_ptr<Message> dynamic_file_proto(
+        factory.GetPrototype(file_proto_desc)->New());
+    GOOGLE_CHECK(dynamic_file_proto.get() != NULL);
+    GOOGLE_CHECK(dynamic_file_proto->ParseFromString(file_data));
+
+    // Collect the extensions again from the dynamic message. There should be no
+    // more unknown fields this time, i.e. all the custom options should be
+    // parsed as extensions now.
+    extensions->clear();
+    GOOGLE_CHECK(CollectExtensions(*dynamic_file_proto, extensions))
+        << "Find unknown fields in FileDescriptorProto when building "
+        << file_proto.name()
+        << ". It's likely that those fields are custom options, however, "
+           "those options cannot be recognized in the builder pool. "
+           "This normally should not happen. Please report a bug.";
+  }
 }
 
 
@@ -306,19 +353,32 @@ void FileGenerator::GenerateEmbeddedDescriptor(io::Printer* printer) {
         .GenerateNonNestedInitializationCode(printer);
   }
 
-  if (UsesExtensions(file_proto)) {
-    // Must construct an ExtensionRegistry containing all possible extensions
+  // Proto compiler builds a DescriptorPool, which holds all the descriptors to
+  // generate, when processing the ".proto" files. We call this DescriptorPool
+  // the parsed pool (a.k.a. file_->pool()).
+  //
+  // Note that when users try to extend the (.*)DescriptorProto in their
+  // ".proto" files, it does not affect the pre-built FileDescriptorProto class
+  // in proto compiler. When we put the descriptor data in the file_proto, those
+  // extensions become unknown fields.
+  //
+  // Now we need to find out all the extension value to the (.*)DescriptorProto
+  // in the file_proto message, and prepare an ExtensionRegistry to return.
+  //
+  // To find those extensions, we need to parse the data into a dynamic message
+  // of the FileDescriptor based on the builder-pool, then we can use
+  // reflections to find all extension fields
+  vector<const FieldDescriptor*> extensions;
+  CollectExtensions(file_proto, *file_->pool(), &extensions, file_data);
+
+  if (extensions.size() > 0) {
+    // Must construct an ExtensionRegistry containing all existing extensions
     // and return it.
     printer->Print(
       "com.google.protobuf.ExtensionRegistry registry =\n"
-      "  com.google.protobuf.ExtensionRegistry.newInstance();\n"
-      "registerAllExtensions(registry);\n");
-    for (int i = 0; i < file_->dependency_count(); i++) {
-      if (ShouldIncludeDependency(file_->dependency(i))) {
-        printer->Print(
-            "$dependency$.registerAllExtensions(registry);\n",
-            "dependency", ClassName(file_->dependency(i)));
-      }
+      "  com.google.protobuf.ExtensionRegistry.newInstance();\n");
+    for (int i = 0; i < extensions.size(); i++) {
+      ExtensionGenerator(extensions[i]).GenerateRegistrationCode(printer);
     }
     printer->Print(
       "return registry;\n");
@@ -375,7 +435,9 @@ static void GenerateSibling(const string& package_dir,
 
   printer.Print(
     "// Generated by the protocol buffer compiler.  DO NOT EDIT!\n"
-    "\n");
+    "// source: $filename$\n"
+    "\n",
+    "filename", descriptor->file()->name());
   if (!java_package.empty()) {
     printer.Print(
       "package $package$;\n"
diff --git a/src/google/protobuf/compiler/java/java_helpers.cc b/src/google/protobuf/compiler/java/java_helpers.cc
index 1b6f1653..cf241b8a 100644
--- a/src/google/protobuf/compiler/java/java_helpers.cc
+++ b/src/google/protobuf/compiler/java/java_helpers.cc
@@ -177,6 +177,18 @@ string ToJavaName(const string& full_name, const FileDescriptor* file) {
   return result;
 }
 
+string ClassName(const Descriptor* descriptor) {
+  return ToJavaName(descriptor->full_name(), descriptor->file());
+}
+
+string ClassName(const EnumDescriptor* descriptor) {
+  return ToJavaName(descriptor->full_name(), descriptor->file());
+}
+
+string ClassName(const ServiceDescriptor* descriptor) {
+  return ToJavaName(descriptor->full_name(), descriptor->file());
+}
+
 string ClassName(const FileDescriptor* descriptor) {
   string result = FileJavaPackage(descriptor);
   if (!result.empty()) result += '.';
@@ -326,14 +338,14 @@ string DefaultValue(const FieldDescriptor* field) {
         } else {
           // See comments in Internal.java for gory details.
           return strings::Substitute(
-            "com.google.protobuf.Internal.stringDefaultValue(\"$0\")",
-            CEscape(field->default_value_string()));
+              "com.google.protobuf.Internal.stringDefaultValue(\"$0\")",
+              CEscape(field->default_value_string()));
         }
       }
 
     case FieldDescriptor::CPPTYPE_ENUM:
       return ClassName(field->enum_type()) + "." +
-             field->default_value_enum()->name();
+          field->default_value_enum()->name();
 
     case FieldDescriptor::CPPTYPE_MESSAGE:
       return ClassName(field->message_type()) + ".getDefaultInstance()";
@@ -427,8 +439,10 @@ string GetBitFieldNameForBit(int bitIndex) {
   return GetBitFieldName(bitIndex / 32);
 }
 
-string GenerateGetBit(int bitIndex) {
-  string varName = GetBitFieldNameForBit(bitIndex);
+namespace {
+
+string GenerateGetBitInternal(const string& prefix, int bitIndex) {
+  string varName = prefix + GetBitFieldNameForBit(bitIndex);
   int bitInVarIndex = bitIndex % 32;
 
   string mask = bit_masks[bitInVarIndex];
@@ -436,8 +450,8 @@ string GenerateGetBit(int bitIndex) {
   return result;
 }
 
-string GenerateSetBit(int bitIndex) {
-  string varName = GetBitFieldNameForBit(bitIndex);
+string GenerateSetBitInternal(const string& prefix, int bitIndex) {
+  string varName = prefix + GetBitFieldNameForBit(bitIndex);
   int bitInVarIndex = bitIndex % 32;
 
   string mask = bit_masks[bitInVarIndex];
@@ -445,6 +459,16 @@ string GenerateSetBit(int bitIndex) {
   return result;
 }
 
+}  // namespace
+
+string GenerateGetBit(int bitIndex) {
+  return GenerateGetBitInternal("", bitIndex);
+}
+
+string GenerateSetBit(int bitIndex) {
+  return GenerateSetBitInternal("", bitIndex);
+}
+
 string GenerateClearBit(int bitIndex) {
   string varName = GetBitFieldNameForBit(bitIndex);
   int bitInVarIndex = bitIndex % 32;
@@ -455,21 +479,19 @@ string GenerateClearBit(int bitIndex) {
 }
 
 string GenerateGetBitFromLocal(int bitIndex) {
-  string varName = "from_" + GetBitFieldNameForBit(bitIndex);
-  int bitInVarIndex = bitIndex % 32;
-
-  string mask = bit_masks[bitInVarIndex];
-  string result = "((" + varName + " & " + mask + ") == " + mask + ")";
-  return result;
+  return GenerateGetBitInternal("from_", bitIndex);
 }
 
 string GenerateSetBitToLocal(int bitIndex) {
-  string varName = "to_" + GetBitFieldNameForBit(bitIndex);
-  int bitInVarIndex = bitIndex % 32;
+  return GenerateSetBitInternal("to_", bitIndex);
+}
 
-  string mask = bit_masks[bitInVarIndex];
-  string result = varName + " |= " + mask;
-  return result;
+string GenerateGetBitMutableLocal(int bitIndex) {
+  return GenerateGetBitInternal("mutable_", bitIndex);
+}
+
+string GenerateSetBitMutableLocal(int bitIndex) {
+  return GenerateSetBitInternal("mutable_", bitIndex);
 }
 
 }  // namespace java
diff --git a/src/google/protobuf/compiler/java/java_helpers.h b/src/google/protobuf/compiler/java/java_helpers.h
index 4ae07f15..3937f069 100644
--- a/src/google/protobuf/compiler/java/java_helpers.h
+++ b/src/google/protobuf/compiler/java/java_helpers.h
@@ -78,19 +78,14 @@ string ToJavaName(const string& full_name, const FileDescriptor* file);
 
 // These return the fully-qualified class name corresponding to the given
 // descriptor.
-inline string ClassName(const Descriptor* descriptor) {
-  return ToJavaName(descriptor->full_name(), descriptor->file());
-}
-inline string ClassName(const EnumDescriptor* descriptor) {
-  return ToJavaName(descriptor->full_name(), descriptor->file());
-}
-inline string ClassName(const ServiceDescriptor* descriptor) {
-  return ToJavaName(descriptor->full_name(), descriptor->file());
-}
+string ClassName(const Descriptor* descriptor);
+string ClassName(const EnumDescriptor* descriptor);
+string ClassName(const ServiceDescriptor* descriptor);
+string ClassName(const FileDescriptor* descriptor);
+
 inline string ExtensionIdentifierName(const FieldDescriptor* descriptor) {
   return ToJavaName(descriptor->full_name(), descriptor->file());
 }
-string ClassName(const FileDescriptor* descriptor);
 
 // Get the unqualified name that should be used for a field's field
 // number constant.
@@ -205,6 +200,18 @@ string GenerateGetBitFromLocal(int bitIndex);
 // Example: "to_bitField1_ = (to_bitField1_ | 0x04)"
 string GenerateSetBitToLocal(int bitIndex);
 
+// Does the same as GenerateGetBit but operates on the bit field on a local
+// variable. This is used by the parsing constructor to record if a repeated
+// field is mutable.
+// Example: "((mutable_bitField1_ & 0x04) == 0x04)"
+string GenerateGetBitMutableLocal(int bitIndex);
+
+// Does the same as GenerateSetBit but operates on the bit field on a local
+// variable. This is used by the parsing constructor to record if a repeated
+// field is mutable.
+// Example: "mutable_bitField1_ = (mutable_bitField1_ | 0x04)"
+string GenerateSetBitMutableLocal(int bitIndex);
+
 }  // namespace java
 }  // namespace compiler
 }  // namespace protobuf
diff --git a/src/google/protobuf/compiler/java/java_message.cc b/src/google/protobuf/compiler/java/java_message.cc
index 4c087db5..9322e242 100644
--- a/src/google/protobuf/compiler/java/java_message.cc
+++ b/src/google/protobuf/compiler/java/java_message.cc
@@ -32,17 +32,23 @@
 //  Based on original Protocol Buffers design by
 //  Sanjay Ghemawat, Jeff Dean, and others.
 
+#include <google/protobuf/compiler/java/java_message.h>
+
 #include <algorithm>
 #include <google/protobuf/stubs/hash.h>
-#include <google/protobuf/compiler/java/java_message.h>
+#include <map>
+#include <vector>
+
+#include <google/protobuf/compiler/java/java_doc_comment.h>
 #include <google/protobuf/compiler/java/java_enum.h>
 #include <google/protobuf/compiler/java/java_extension.h>
 #include <google/protobuf/compiler/java/java_helpers.h>
-#include <google/protobuf/stubs/strutil.h>
-#include <google/protobuf/io/printer.h>
 #include <google/protobuf/io/coded_stream.h>
-#include <google/protobuf/wire_format.h>
+#include <google/protobuf/io/printer.h>
 #include <google/protobuf/descriptor.pb.h>
+#include <google/protobuf/wire_format.h>
+#include <google/protobuf/stubs/strutil.h>
+#include <google/protobuf/stubs/substitute.h>
 
 namespace google {
 namespace protobuf {
@@ -233,10 +239,8 @@ void MessageGenerator::GenerateStaticVariableInitializers(
         "field_name",
           UnderscoresToCapitalizedCamelCase(descriptor_->field(i)));
     }
-    printer->Print("},\n"
-      "    $classname$.class,\n"
-      "    $classname$.Builder.class);\n",
-      "classname", ClassName(descriptor_));
+    printer->Print(
+        "});\n");
   }
 
   // Generate static member initializers for all nested types.
@@ -250,7 +254,6 @@ void MessageGenerator::GenerateStaticVariableInitializers(
 // ===================================================================
 
 void MessageGenerator::GenerateInterface(io::Printer* printer) {
-
   if (descriptor_->extension_range_count() > 0) {
     if (HasDescriptorMethods(descriptor_)) {
       printer->Print(
@@ -298,6 +301,10 @@ void MessageGenerator::Generate(io::Printer* printer) {
     descriptor_->containing_type() == NULL &&
     descriptor_->file()->options().java_multiple_files();
 
+  WriteMessageDocComment(printer, descriptor_);
+
+  // The builder_type stores the super type name of the nested Builder class.
+  string builder_type;
   if (descriptor_->extension_range_count() > 0) {
     if (HasDescriptorMethods(descriptor_)) {
       printer->Print(
@@ -306,6 +313,9 @@ void MessageGenerator::Generate(io::Printer* printer) {
         "      $classname$> implements $classname$OrBuilder {\n",
         "static", is_own_file ? "" : "static",
         "classname", descriptor_->name());
+      builder_type = strings::Substitute(
+          "com.google.protobuf.GeneratedMessage.ExtendableBuilder<$0, ?>",
+          ClassName(descriptor_));
     } else {
       printer->Print(
         "public $static$ final class $classname$ extends\n"
@@ -313,6 +323,9 @@ void MessageGenerator::Generate(io::Printer* printer) {
         "      $classname$> implements $classname$OrBuilder {\n",
         "static", is_own_file ? "" : "static",
         "classname", descriptor_->name());
+      builder_type = strings::Substitute(
+          "com.google.protobuf.GeneratedMessageLite.ExtendableBuilder<$0, ?>",
+          ClassName(descriptor_));
     }
   } else {
     if (HasDescriptorMethods(descriptor_)) {
@@ -322,6 +335,7 @@ void MessageGenerator::Generate(io::Printer* printer) {
         "    implements $classname$OrBuilder {\n",
         "static", is_own_file ? "" : "static",
         "classname", descriptor_->name());
+      builder_type = "com.google.protobuf.GeneratedMessage.Builder<?>";
     } else {
       printer->Print(
         "public $static$ final class $classname$ extends\n"
@@ -329,17 +343,28 @@ void MessageGenerator::Generate(io::Printer* printer) {
         "    implements $classname$OrBuilder {\n",
         "static", is_own_file ? "" : "static",
         "classname", descriptor_->name());
+      builder_type = "com.google.protobuf.GeneratedMessageLite.Builder";
     }
   }
   printer->Indent();
+  // Using builder_type, instead of Builder, prevents the Builder class from
+  // being loaded into PermGen space when the default instance is created.
+  // This optimizes the PermGen space usage for clients that do not modify
+  // messages.
   printer->Print(
     "// Use $classname$.newBuilder() to construct.\n"
-    "private $classname$(Builder builder) {\n"
+    "private $classname$($buildertype$ builder) {\n"
     "  super(builder);\n"
-    "}\n"
+    "$set_unknown_fields$\n"
+    "}\n",
+    "classname", descriptor_->name(),
+    "buildertype", builder_type,
+    "set_unknown_fields", HasUnknownFields(descriptor_)
+        ? "  this.unknownFields = builder.getUnknownFields();" : "");
+  printer->Print(
     // Used when constructing the default instance, which cannot be initialized
     // immediately because it may cyclically refer to other default instances.
-    "private $classname$(boolean noInit) {}\n"
+    "private $classname$(boolean noInit) {$set_default_unknown_fields$}\n"
     "\n"
     "private static final $classname$ defaultInstance;\n"
     "public static $classname$ getDefaultInstance() {\n"
@@ -350,9 +375,28 @@ void MessageGenerator::Generate(io::Printer* printer) {
     "  return defaultInstance;\n"
     "}\n"
     "\n",
-    "classname", descriptor_->name());
+    "classname", descriptor_->name(),
+    "set_default_unknown_fields", HasUnknownFields(descriptor_)
+        ? " this.unknownFields ="
+          " com.google.protobuf.UnknownFieldSet.getDefaultInstance(); " : "");
+
+  if (HasUnknownFields(descriptor_)) {
+    printer->Print(
+        "private final com.google.protobuf.UnknownFieldSet unknownFields;\n"
+        ""
+        "@java.lang.Override\n"
+        "public final com.google.protobuf.UnknownFieldSet\n"
+        "    getUnknownFields() {\n"
+        "  return this.unknownFields;\n"
+        "}\n");
+  }
+
+  if (HasGeneratedMethods(descriptor_)) {
+    GenerateParsingConstructor(printer);
+  }
 
   GenerateDescriptorMethods(printer);
+  GenerateParser(printer);
 
   // Nested types
   for (int i = 0; i < descriptor_->enum_type_count(); i++) {
@@ -567,68 +611,54 @@ GenerateParseFromMethods(io::Printer* printer) {
     "public static $classname$ parseFrom(\n"
     "    com.google.protobuf.ByteString data)\n"
     "    throws com.google.protobuf.InvalidProtocolBufferException {\n"
-    "  return newBuilder().mergeFrom(data).buildParsed();\n"
+    "  return PARSER.parseFrom(data);\n"
     "}\n"
     "public static $classname$ parseFrom(\n"
     "    com.google.protobuf.ByteString data,\n"
     "    com.google.protobuf.ExtensionRegistryLite extensionRegistry)\n"
     "    throws com.google.protobuf.InvalidProtocolBufferException {\n"
-    "  return newBuilder().mergeFrom(data, extensionRegistry)\n"
-    "           .buildParsed();\n"
+    "  return PARSER.parseFrom(data, extensionRegistry);\n"
     "}\n"
     "public static $classname$ parseFrom(byte[] data)\n"
     "    throws com.google.protobuf.InvalidProtocolBufferException {\n"
-    "  return newBuilder().mergeFrom(data).buildParsed();\n"
+    "  return PARSER.parseFrom(data);\n"
     "}\n"
     "public static $classname$ parseFrom(\n"
     "    byte[] data,\n"
     "    com.google.protobuf.ExtensionRegistryLite extensionRegistry)\n"
     "    throws com.google.protobuf.InvalidProtocolBufferException {\n"
-    "  return newBuilder().mergeFrom(data, extensionRegistry)\n"
-    "           .buildParsed();\n"
+    "  return PARSER.parseFrom(data, extensionRegistry);\n"
     "}\n"
     "public static $classname$ parseFrom(java.io.InputStream input)\n"
     "    throws java.io.IOException {\n"
-    "  return newBuilder().mergeFrom(input).buildParsed();\n"
+    "  return PARSER.parseFrom(input);\n"
     "}\n"
     "public static $classname$ parseFrom(\n"
     "    java.io.InputStream input,\n"
     "    com.google.protobuf.ExtensionRegistryLite extensionRegistry)\n"
     "    throws java.io.IOException {\n"
-    "  return newBuilder().mergeFrom(input, extensionRegistry)\n"
-    "           .buildParsed();\n"
+    "  return PARSER.parseFrom(input, extensionRegistry);\n"
     "}\n"
     "public static $classname$ parseDelimitedFrom(java.io.InputStream input)\n"
     "    throws java.io.IOException {\n"
-    "  Builder builder = newBuilder();\n"
-    "  if (builder.mergeDelimitedFrom(input)) {\n"
-    "    return builder.buildParsed();\n"
-    "  } else {\n"
-    "    return null;\n"
-    "  }\n"
+    "  return PARSER.parseDelimitedFrom(input);\n"
     "}\n"
     "public static $classname$ parseDelimitedFrom(\n"
     "    java.io.InputStream input,\n"
     "    com.google.protobuf.ExtensionRegistryLite extensionRegistry)\n"
     "    throws java.io.IOException {\n"
-    "  Builder builder = newBuilder();\n"
-    "  if (builder.mergeDelimitedFrom(input, extensionRegistry)) {\n"
-    "    return builder.buildParsed();\n"
-    "  } else {\n"
-    "    return null;\n"
-    "  }\n"
+    "  return PARSER.parseDelimitedFrom(input, extensionRegistry);\n"
     "}\n"
     "public static $classname$ parseFrom(\n"
     "    com.google.protobuf.CodedInputStream input)\n"
     "    throws java.io.IOException {\n"
-    "  return newBuilder().mergeFrom(input).buildParsed();\n"
+    "  return PARSER.parseFrom(input);\n"
     "}\n"
     "public static $classname$ parseFrom(\n"
     "    com.google.protobuf.CodedInputStream input,\n"
     "    com.google.protobuf.ExtensionRegistryLite extensionRegistry)\n"
     "    throws java.io.IOException {\n"
-    "  return newBuilder().mergeFrom(input, extensionRegistry)\n"
-    "           .buildParsed();\n"
+    "  return PARSER.parseFrom(input, extensionRegistry);\n"
     "}\n"
     "\n",
     "classname", ClassName(descriptor_));
@@ -669,6 +699,8 @@ void MessageGenerator::GenerateBuilder(io::Printer* printer) {
       "}\n");
   }
 
+  WriteMessageDocComment(printer, descriptor_);
+
   if (descriptor_->extension_range_count() > 0) {
     if (HasDescriptorMethods(descriptor_)) {
       printer->Print(
@@ -739,17 +771,25 @@ void MessageGenerator::GenerateBuilder(io::Printer* printer) {
 
 void MessageGenerator::GenerateDescriptorMethods(io::Printer* printer) {
   if (HasDescriptorMethods(descriptor_)) {
+    if (!descriptor_->options().no_standard_descriptor_accessor()) {
+      printer->Print(
+        "public static final com.google.protobuf.Descriptors.Descriptor\n"
+        "    getDescriptor() {\n"
+        "  return $fileclass$.internal_$identifier$_descriptor;\n"
+        "}\n"
+        "\n",
+        "fileclass", ClassName(descriptor_->file()),
+        "identifier", UniqueFileScopeIdentifier(descriptor_));
+    }
     printer->Print(
-      "public static final com.google.protobuf.Descriptors.Descriptor\n"
-      "    getDescriptor() {\n"
-      "  return $fileclass$.internal_$identifier$_descriptor;\n"
-      "}\n"
-      "\n"
       "protected com.google.protobuf.GeneratedMessage.FieldAccessorTable\n"
       "    internalGetFieldAccessorTable() {\n"
-      "  return $fileclass$.internal_$identifier$_fieldAccessorTable;\n"
+      "  return $fileclass$.internal_$identifier$_fieldAccessorTable\n"
+      "      .ensureFieldAccessorsInitialized(\n"
+      "          $classname$.class, $classname$.Builder.class);\n"
       "}\n"
       "\n",
+      "classname", ClassName(descriptor_),
       "fileclass", ClassName(descriptor_->file()),
       "identifier", UniqueFileScopeIdentifier(descriptor_));
   }
@@ -768,7 +808,8 @@ void MessageGenerator::GenerateCommonBuilderMethods(io::Printer* printer) {
 
   if (HasDescriptorMethods(descriptor_)) {
     printer->Print(
-      "private Builder(BuilderParent parent) {\n"
+      "private Builder(\n"
+      "    com.google.protobuf.GeneratedMessage.BuilderParent parent) {\n"
       "  super(parent);\n"
       "  maybeForceBuilderInitialization();\n"
       "}\n",
@@ -830,10 +871,11 @@ void MessageGenerator::GenerateCommonBuilderMethods(io::Printer* printer) {
     printer->Print(
       "public com.google.protobuf.Descriptors.Descriptor\n"
       "    getDescriptorForType() {\n"
-      "  return $classname$.getDescriptor();\n"
+      "  return $fileclass$.internal_$identifier$_descriptor;\n"
       "}\n"
       "\n",
-      "classname", ClassName(descriptor_));
+      "fileclass", ClassName(descriptor_->file()),
+      "identifier", UniqueFileScopeIdentifier(descriptor_));
   }
   printer->Print(
     "public $classname$ getDefaultInstanceForType() {\n"
@@ -853,16 +895,6 @@ void MessageGenerator::GenerateCommonBuilderMethods(io::Printer* printer) {
     "  return result;\n"
     "}\n"
     "\n"
-    "private $classname$ buildParsed()\n"
-    "    throws com.google.protobuf.InvalidProtocolBufferException {\n"
-    "  $classname$ result = buildPartial();\n"
-    "  if (!result.isInitialized()) {\n"
-    "    throw newUninitializedMessageException(\n"
-    "      result).asInvalidProtocolBufferException();\n"
-    "  }\n"
-    "  return result;\n"
-    "}\n"
-    "\n"
     "public $classname$ buildPartial() {\n"
     "  $classname$ result = new $classname$(this);\n",
     "classname", ClassName(descriptor_));
@@ -969,108 +1001,25 @@ void MessageGenerator::GenerateCommonBuilderMethods(io::Printer* printer) {
 // ===================================================================
 
 void MessageGenerator::GenerateBuilderParsingMethods(io::Printer* printer) {
-  scoped_array<const FieldDescriptor*> sorted_fields(
-    SortFieldsByNumber(descriptor_));
-
   printer->Print(
     "public Builder mergeFrom(\n"
     "    com.google.protobuf.CodedInputStream input,\n"
     "    com.google.protobuf.ExtensionRegistryLite extensionRegistry)\n"
-    "    throws java.io.IOException {\n");
-  printer->Indent();
-
-  if (HasUnknownFields(descriptor_)) {
-    printer->Print(
-      "com.google.protobuf.UnknownFieldSet.Builder unknownFields =\n"
-      "  com.google.protobuf.UnknownFieldSet.newBuilder(\n"
-      "    this.getUnknownFields());\n");
-  }
-
-  printer->Print(
-    "while (true) {\n");
-  printer->Indent();
-
-  printer->Print(
-    "int tag = input.readTag();\n"
-    "switch (tag) {\n");
-  printer->Indent();
-
-  if (HasUnknownFields(descriptor_)) {
-    printer->Print(
-      "case 0:\n"          // zero signals EOF / limit reached
-      "  this.setUnknownFields(unknownFields.build());\n"
-      "  $on_changed$\n"
-      "  return this;\n"
-      "default: {\n"
-      "  if (!parseUnknownField(input, unknownFields,\n"
-      "                         extensionRegistry, tag)) {\n"
-      "    this.setUnknownFields(unknownFields.build());\n"
-      "    $on_changed$\n"
-      "    return this;\n"   // it's an endgroup tag
-      "  }\n"
-      "  break;\n"
-      "}\n",
-      "on_changed", HasDescriptorMethods(descriptor_) ? "onChanged();" : "");
-  } else {
-    printer->Print(
-      "case 0:\n"          // zero signals EOF / limit reached
-      "  $on_changed$\n"
-      "  return this;\n"
-      "default: {\n"
-      "  if (!parseUnknownField(input, extensionRegistry, tag)) {\n"
-      "    $on_changed$\n"
-      "    return this;\n"   // it's an endgroup tag
-      "  }\n"
-      "  break;\n"
-      "}\n",
-      "on_changed", HasDescriptorMethods(descriptor_) ? "onChanged();" : "");
-  }
-
-  for (int i = 0; i < descriptor_->field_count(); i++) {
-    const FieldDescriptor* field = sorted_fields[i];
-    uint32 tag = WireFormatLite::MakeTag(field->number(),
-      WireFormat::WireTypeForFieldType(field->type()));
-
-    printer->Print(
-      "case $tag$: {\n",
-      "tag", SimpleItoa(tag));
-    printer->Indent();
-
-    field_generators_.get(field).GenerateParsingCode(printer);
-
-    printer->Outdent();
-    printer->Print(
-      "  break;\n"
-      "}\n");
-
-    if (field->is_packable()) {
-      // To make packed = true wire compatible, we generate parsing code from a
-      // packed version of this field regardless of field->options().packed().
-      uint32 packed_tag = WireFormatLite::MakeTag(field->number(),
-        WireFormatLite::WIRETYPE_LENGTH_DELIMITED);
-      printer->Print(
-        "case $tag$: {\n",
-        "tag", SimpleItoa(packed_tag));
-      printer->Indent();
-
-      field_generators_.get(field).GenerateParsingCodeFromPacked(printer);
-
-      printer->Outdent();
-      printer->Print(
-        "  break;\n"
-        "}\n");
-    }
-  }
-
-  printer->Outdent();
-  printer->Outdent();
-  printer->Outdent();
-  printer->Print(
-    "    }\n"     // switch (tag)
-    "  }\n"       // while (true)
-    "}\n"
-
-    "\n");
+    "    throws java.io.IOException {\n"
+    "  $classname$ parsedMessage = null;\n"
+    "  try {\n"
+    "    parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);\n"
+    "  } catch (com.google.protobuf.InvalidProtocolBufferException e) {\n"
+    "    parsedMessage = ($classname$) e.getUnfinishedMessage();\n"
+    "    throw e;\n"
+    "  } finally {\n"
+    "    if (parsedMessage != null) {\n"
+    "      mergeFrom(parsedMessage);\n"
+    "    }\n"
+    "  }\n"
+    "  return this;\n"
+    "}\n",
+    "classname", ClassName(descriptor_));
 }
 
 // ===================================================================
@@ -1232,10 +1181,19 @@ void MessageGenerator::GenerateEqualsAndHashCode(io::Printer* printer) {
     "\n");
 
   printer->Print(
+    "private int memoizedHashCode = 0;\n");
+  printer->Print(
     "@java.lang.Override\n"
     "public int hashCode() {\n");
   printer->Indent();
   printer->Print(
+    "if (memoizedHashCode != 0) {\n");
+  printer->Indent();
+  printer->Print(
+    "return memoizedHashCode;\n");
+  printer->Outdent();
+  printer->Print(
+    "}\n"
     "int hash = 41;\n"
     "hash = (19 * hash) + getDescriptorForType().hashCode();\n");
   for (int i = 0; i < descriptor_->field_count(); i++) {
@@ -1260,6 +1218,7 @@ void MessageGenerator::GenerateEqualsAndHashCode(io::Printer* printer) {
   }
   printer->Print(
     "hash = (29 * hash) + getUnknownFields().hashCode();\n"
+    "memoizedHashCode = hash;\n"
     "return hash;\n");
   printer->Outdent();
   printer->Print(
@@ -1281,6 +1240,195 @@ void MessageGenerator::GenerateExtensionRegistrationCode(io::Printer* printer) {
   }
 }
 
+// ===================================================================
+void MessageGenerator::GenerateParsingConstructor(io::Printer* printer) {
+  scoped_array<const FieldDescriptor*> sorted_fields(
+      SortFieldsByNumber(descriptor_));
+
+  printer->Print(
+      "private $classname$(\n"
+      "    com.google.protobuf.CodedInputStream input,\n"
+      "    com.google.protobuf.ExtensionRegistryLite extensionRegistry)\n"
+      "    throws com.google.protobuf.InvalidProtocolBufferException {\n",
+      "classname", descriptor_->name());
+  printer->Indent();
+
+  // Initialize all fields to default.
+  printer->Print(
+      "initFields();\n");
+
+  // Use builder bits to track mutable repeated fields.
+  int totalBuilderBits = 0;
+  for (int i = 0; i < descriptor_->field_count(); i++) {
+    const FieldGenerator& field = field_generators_.get(descriptor_->field(i));
+    totalBuilderBits += field.GetNumBitsForBuilder();
+  }
+  int totalBuilderInts = (totalBuilderBits + 31) / 32;
+  for (int i = 0; i < totalBuilderInts; i++) {
+    printer->Print("int mutable_$bit_field_name$ = 0;\n",
+      "bit_field_name", GetBitFieldName(i));
+  }
+
+  if (HasUnknownFields(descriptor_)) {
+    printer->Print(
+      "com.google.protobuf.UnknownFieldSet.Builder unknownFields =\n"
+      "    com.google.protobuf.UnknownFieldSet.newBuilder();\n");
+  }
+
+  printer->Print(
+      "try {\n");
+  printer->Indent();
+
+  printer->Print(
+    "boolean done = false;\n"
+    "while (!done) {\n");
+  printer->Indent();
+
+  printer->Print(
+    "int tag = input.readTag();\n"
+    "switch (tag) {\n");
+  printer->Indent();
+
+  printer->Print(
+    "case 0:\n"          // zero signals EOF / limit reached
+    "  done = true;\n"
+    "  break;\n"
+    "default: {\n"
+    "  if (!parseUnknownField(input,$unknown_fields$\n"
+    "                         extensionRegistry, tag)) {\n"
+    "    done = true;\n"  // it's an endgroup tag
+    "  }\n"
+    "  break;\n"
+    "}\n",
+    "unknown_fields", HasUnknownFields(descriptor_)
+        ? " unknownFields," : "");
+
+  for (int i = 0; i < descriptor_->field_count(); i++) {
+    const FieldDescriptor* field = sorted_fields[i];
+    uint32 tag = WireFormatLite::MakeTag(field->number(),
+      WireFormat::WireTypeForFieldType(field->type()));
+
+    printer->Print(
+      "case $tag$: {\n",
+      "tag", SimpleItoa(tag));
+    printer->Indent();
+
+    field_generators_.get(field).GenerateParsingCode(printer);
+
+    printer->Outdent();
+    printer->Print(
+      "  break;\n"
+      "}\n");
+
+    if (field->is_packable()) {
+      // To make packed = true wire compatible, we generate parsing code from a
+      // packed version of this field regardless of field->options().packed().
+      uint32 packed_tag = WireFormatLite::MakeTag(field->number(),
+        WireFormatLite::WIRETYPE_LENGTH_DELIMITED);
+      printer->Print(
+        "case $tag$: {\n",
+        "tag", SimpleItoa(packed_tag));
+      printer->Indent();
+
+      field_generators_.get(field).GenerateParsingCodeFromPacked(printer);
+
+      printer->Outdent();
+      printer->Print(
+        "  break;\n"
+        "}\n");
+    }
+  }
+
+  printer->Outdent();
+  printer->Outdent();
+  printer->Print(
+      "  }\n"     // switch (tag)
+      "}\n");     // while (!done)
+
+  printer->Outdent();
+  printer->Print(
+      "} catch (com.google.protobuf.InvalidProtocolBufferException e) {\n"
+      "  throw e.setUnfinishedMessage(this);\n"
+      "} catch (java.io.IOException e) {\n"
+      "  throw new com.google.protobuf.InvalidProtocolBufferException(\n"
+      "      e.getMessage()).setUnfinishedMessage(this);\n"
+      "} finally {\n");
+  printer->Indent();
+
+  // Make repeated field list immutable.
+  for (int i = 0; i < descriptor_->field_count(); i++) {
+    const FieldDescriptor* field = sorted_fields[i];
+    field_generators_.get(field).GenerateParsingDoneCode(printer);
+  }
+
+  // Make unknown fields immutable.
+  if (HasUnknownFields(descriptor_)) {
+    printer->Print(
+        "this.unknownFields = unknownFields.build();\n");
+  }
+
+  // Make extensions immutable.
+  printer->Print(
+      "makeExtensionsImmutable();\n");
+
+  printer->Outdent();
+  printer->Outdent();
+  printer->Print(
+      "  }\n"     // finally
+      "}\n");
+}
+
+// ===================================================================
+void MessageGenerator::GenerateParser(io::Printer* printer) {
+  printer->Print(
+      "public static com.google.protobuf.Parser<$classname$> PARSER =\n"
+      "    new com.google.protobuf.AbstractParser<$classname$>() {\n",
+      "classname", descriptor_->name());
+  printer->Indent();
+  printer->Print(
+      "public $classname$ parsePartialFrom(\n"
+      "    com.google.protobuf.CodedInputStream input,\n"
+      "    com.google.protobuf.ExtensionRegistryLite extensionRegistry)\n"
+      "    throws com.google.protobuf.InvalidProtocolBufferException {\n",
+      "classname", descriptor_->name());
+  if (HasGeneratedMethods(descriptor_)) {
+    printer->Print(
+        "  return new $classname$(input, extensionRegistry);\n",
+        "classname", descriptor_->name());
+  } else {
+    // When parsing constructor isn't generated, use builder to parse messages.
+    // Note, will fallback to use reflection based mergeFieldFrom() in
+    // AbstractMessage.Builder.
+    printer->Indent();
+    printer->Print(
+        "Builder builder = newBuilder();\n"
+        "try {\n"
+        "  builder.mergeFrom(input, extensionRegistry);\n"
+        "} catch (com.google.protobuf.InvalidProtocolBufferException e) {\n"
+        "  throw e.setUnfinishedMessage(builder.buildPartial());\n"
+        "} catch (java.io.IOException e) {\n"
+        "  throw new com.google.protobuf.InvalidProtocolBufferException(\n"
+        "      e.getMessage()).setUnfinishedMessage(builder.buildPartial());\n"
+        "}\n"
+        "return builder.buildPartial();\n");
+    printer->Outdent();
+  }
+  printer->Print(
+        "}\n");
+  printer->Outdent();
+  printer->Print(
+      "};\n"
+      "\n");
+
+  printer->Print(
+      "@java.lang.Override\n"
+      "public com.google.protobuf.Parser<$classname$> getParserForType() {\n"
+      "  return PARSER;\n"
+      "}\n"
+      "\n",
+      "classname", descriptor_->name());
+}
+
 }  // namespace java
 }  // namespace compiler
 }  // namespace protobuf
diff --git a/src/google/protobuf/compiler/java/java_message.h b/src/google/protobuf/compiler/java/java_message.h
index 4c6fbbe5..a30f0202 100644
--- a/src/google/protobuf/compiler/java/java_message.h
+++ b/src/google/protobuf/compiler/java/java_message.h
@@ -95,6 +95,9 @@ class MessageGenerator {
       UseMemoization useMemoization);
   void GenerateEqualsAndHashCode(io::Printer* printer);
 
+  void GenerateParser(io::Printer* printer);
+  void GenerateParsingConstructor(io::Printer* printer);
+
   const Descriptor* descriptor_;
   FieldGeneratorMap field_generators_;
 
diff --git a/src/google/protobuf/compiler/java/java_message_field.cc b/src/google/protobuf/compiler/java/java_message_field.cc
index 251945af..b0b284f7 100644
--- a/src/google/protobuf/compiler/java/java_message_field.cc
+++ b/src/google/protobuf/compiler/java/java_message_field.cc
@@ -36,6 +36,7 @@
 #include <string>
 
 #include <google/protobuf/compiler/java/java_message_field.h>
+#include <google/protobuf/compiler/java/java_doc_comment.h>
 #include <google/protobuf/compiler/java/java_helpers.h>
 #include <google/protobuf/io/printer.h>
 #include <google/protobuf/wire_format.h>
@@ -73,6 +74,7 @@ void SetMessageVariables(const FieldDescriptor* descriptor,
 
   // For singular messages and builders, one bit is used for the hasField bit.
   (*variables)["get_has_field_bit_message"] = GenerateGetBit(messageBitIndex);
+  (*variables)["set_has_field_bit_message"] = GenerateSetBit(messageBitIndex);
 
   (*variables)["get_has_field_bit_builder"] = GenerateGetBit(builderBitIndex);
   (*variables)["set_has_field_bit_builder"] = GenerateSetBit(builderBitIndex);
@@ -84,6 +86,13 @@ void SetMessageVariables(const FieldDescriptor* descriptor,
   (*variables)["set_mutable_bit_builder"] = GenerateSetBit(builderBitIndex);
   (*variables)["clear_mutable_bit_builder"] = GenerateClearBit(builderBitIndex);
 
+  // For repeated fields, one bit is used for whether the array is immutable
+  // in the parsing constructor.
+  (*variables)["get_mutable_bit_parser"] =
+      GenerateGetBitMutableLocal(builderBitIndex);
+  (*variables)["set_mutable_bit_parser"] =
+      GenerateSetBitMutableLocal(builderBitIndex);
+
   (*variables)["get_has_field_bit_from_local"] =
       GenerateGetBitFromLocal(builderBitIndex);
   (*variables)["set_has_field_bit_to_local"] =
@@ -120,11 +129,15 @@ GenerateInterfaceMembers(io::Printer* printer) const {
   // interface so that builders can choose dynamically to either return a
   // message or a nested builder, so that asking for the interface doesn't
   // cause a message to ever be built.
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
+    "$deprecation$boolean has$capitalized_name$();\n");
+  WriteFieldDocComment(printer, descriptor_);
   printer->Print(variables_,
-    "$deprecation$boolean has$capitalized_name$();\n"
     "$deprecation$$type$ get$capitalized_name$();\n");
 
   if (HasNestedBuilders(descriptor_->containing_type())) {
+    WriteFieldDocComment(printer, descriptor_);
     printer->Print(variables_,
       "$deprecation$$type$OrBuilder get$capitalized_name$OrBuilder();\n");
   }
@@ -133,15 +146,20 @@ GenerateInterfaceMembers(io::Printer* printer) const {
 void MessageFieldGenerator::
 GenerateMembers(io::Printer* printer) const {
   printer->Print(variables_,
-    "private $type$ $name$_;\n"
+    "private $type$ $name$_;\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public boolean has$capitalized_name$() {\n"
     "  return $get_has_field_bit_message$;\n"
-    "}\n"
+    "}\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public $type$ get$capitalized_name$() {\n"
     "  return $name$_;\n"
     "}\n");
 
   if (HasNestedBuilders(descriptor_->containing_type())) {
+    WriteFieldDocComment(printer, descriptor_);
     printer->Print(variables_,
       "$deprecation$public $type$OrBuilder get$capitalized_name$OrBuilder() {\n"
       "  return $name$_;\n"
@@ -208,12 +226,14 @@ GenerateBuilderMembers(io::Printer* printer) const {
   // field of type "Field" called "Field".
 
   // boolean hasField()
+  WriteFieldDocComment(printer, descriptor_);
   printer->Print(variables_,
     "$deprecation$public boolean has$capitalized_name$() {\n"
     "  return $get_has_field_bit_builder$;\n"
     "}\n");
 
   // Field getField()
+  WriteFieldDocComment(printer, descriptor_);
   PrintNestedBuilderFunction(printer,
     "$deprecation$public $type$ get$capitalized_name$()",
 
@@ -224,6 +244,7 @@ GenerateBuilderMembers(io::Printer* printer) const {
     NULL);
 
   // Field.Builder setField(Field value)
+  WriteFieldDocComment(printer, descriptor_);
   PrintNestedBuilderFunction(printer,
     "$deprecation$public Builder set$capitalized_name$($type$ value)",
 
@@ -239,6 +260,7 @@ GenerateBuilderMembers(io::Printer* printer) const {
     "return this;\n");
 
   // Field.Builder setField(Field.Builder builderForValue)
+  WriteFieldDocComment(printer, descriptor_);
   PrintNestedBuilderFunction(printer,
     "$deprecation$public Builder set$capitalized_name$(\n"
     "    $type$.Builder builderForValue)",
@@ -252,6 +274,7 @@ GenerateBuilderMembers(io::Printer* printer) const {
     "return this;\n");
 
   // Field.Builder mergeField(Field value)
+  WriteFieldDocComment(printer, descriptor_);
   PrintNestedBuilderFunction(printer,
     "$deprecation$public Builder merge$capitalized_name$($type$ value)",
 
@@ -270,6 +293,7 @@ GenerateBuilderMembers(io::Printer* printer) const {
     "return this;\n");
 
   // Field.Builder clearField()
+  WriteFieldDocComment(printer, descriptor_);
   PrintNestedBuilderFunction(printer,
     "$deprecation$public Builder clear$capitalized_name$()",
 
@@ -282,19 +306,24 @@ GenerateBuilderMembers(io::Printer* printer) const {
     "return this;\n");
 
   if (HasNestedBuilders(descriptor_->containing_type())) {
+    WriteFieldDocComment(printer, descriptor_);
     printer->Print(variables_,
       "$deprecation$public $type$.Builder get$capitalized_name$Builder() {\n"
       "  $set_has_field_bit_builder$;\n"
       "  $on_changed$\n"
       "  return get$capitalized_name$FieldBuilder().getBuilder();\n"
-      "}\n"
+      "}\n");
+    WriteFieldDocComment(printer, descriptor_);
+    printer->Print(variables_,
       "$deprecation$public $type$OrBuilder get$capitalized_name$OrBuilder() {\n"
       "  if ($name$Builder_ != null) {\n"
       "    return $name$Builder_.getMessageOrBuilder();\n"
       "  } else {\n"
       "    return $name$_;\n"
       "  }\n"
-      "}\n"
+      "}\n");
+    WriteFieldDocComment(printer, descriptor_);
+    printer->Print(variables_,
       "private com.google.protobuf.SingleFieldBuilder<\n"
       "    $type$, $type$.Builder, $type$OrBuilder> \n"
       "    get$capitalized_name$FieldBuilder() {\n"
@@ -357,21 +386,32 @@ GenerateBuildingCode(io::Printer* printer) const {
 void MessageFieldGenerator::
 GenerateParsingCode(io::Printer* printer) const {
   printer->Print(variables_,
-    "$type$.Builder subBuilder = $type$.newBuilder();\n"
-    "if (has$capitalized_name$()) {\n"
-    "  subBuilder.mergeFrom(get$capitalized_name$());\n"
+    "$type$.Builder subBuilder = null;\n"
+    "if ($get_has_field_bit_message$) {\n"
+    "  subBuilder = $name$_.toBuilder();\n"
     "}\n");
 
   if (GetType(descriptor_) == FieldDescriptor::TYPE_GROUP) {
     printer->Print(variables_,
-      "input.readGroup($number$, subBuilder, extensionRegistry);\n");
+      "$name$_ = input.readGroup($number$, $type$.PARSER,\n"
+      "    extensionRegistry);\n");
   } else {
     printer->Print(variables_,
-      "input.readMessage(subBuilder, extensionRegistry);\n");
+      "$name$_ = input.readMessage($type$.PARSER, extensionRegistry);\n");
   }
 
   printer->Print(variables_,
-    "set$capitalized_name$(subBuilder.buildPartial());\n");
+    "if (subBuilder != null) {\n"
+    "  subBuilder.mergeFrom($name$_);\n"
+    "  $name$_ = subBuilder.buildPartial();\n"
+    "}\n");
+  printer->Print(variables_,
+    "$set_has_field_bit_message$;\n");
+}
+
+void MessageFieldGenerator::
+GenerateParsingDoneCode(io::Printer* printer) const {
+  // noop for messages.
 }
 
 void MessageFieldGenerator::
@@ -437,15 +477,23 @@ GenerateInterfaceMembers(io::Printer* printer) const {
   // interface so that builders can choose dynamically to either return a
   // message or a nested builder, so that asking for the interface doesn't
   // cause a message to ever be built.
+  WriteFieldDocComment(printer, descriptor_);
   printer->Print(variables_,
     "$deprecation$java.util.List<$type$> \n"
-    "    get$capitalized_name$List();\n"
-    "$deprecation$$type$ get$capitalized_name$(int index);\n"
+    "    get$capitalized_name$List();\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
+    "$deprecation$$type$ get$capitalized_name$(int index);\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$int get$capitalized_name$Count();\n");
   if (HasNestedBuilders(descriptor_->containing_type())) {
+    WriteFieldDocComment(printer, descriptor_);
     printer->Print(variables_,
       "$deprecation$java.util.List<? extends $type$OrBuilder> \n"
-      "    get$capitalized_name$OrBuilderList();\n"
+      "    get$capitalized_name$OrBuilderList();\n");
+    WriteFieldDocComment(printer, descriptor_);
+    printer->Print(variables_,
       "$deprecation$$type$OrBuilder get$capitalized_name$OrBuilder(\n"
       "    int index);\n");
   }
@@ -454,20 +502,30 @@ GenerateInterfaceMembers(io::Printer* printer) const {
 void RepeatedMessageFieldGenerator::
 GenerateMembers(io::Printer* printer) const {
   printer->Print(variables_,
-    "private java.util.List<$type$> $name$_;\n"
+    "private java.util.List<$type$> $name$_;\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public java.util.List<$type$> get$capitalized_name$List() {\n"
     "  return $name$_;\n"   // note:  unmodifiable list
-    "}\n"
+    "}\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public java.util.List<? extends $type$OrBuilder> \n"
     "    get$capitalized_name$OrBuilderList() {\n"
     "  return $name$_;\n"
-    "}\n"
+    "}\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public int get$capitalized_name$Count() {\n"
     "  return $name$_.size();\n"
-    "}\n"
+    "}\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public $type$ get$capitalized_name$(int index) {\n"
     "  return $name$_.get(index);\n"
-    "}\n"
+    "}\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public $type$OrBuilder get$capitalized_name$OrBuilder(\n"
     "    int index) {\n"
     "  return $name$_.get(index);\n"
@@ -552,6 +610,7 @@ GenerateBuilderMembers(io::Printer* printer) const {
   // repeated field of type "Field" called "RepeatedField".
 
   // List<Field> getRepeatedFieldList()
+  WriteFieldDocComment(printer, descriptor_);
   PrintNestedBuilderFunction(printer,
     "$deprecation$public java.util.List<$type$> get$capitalized_name$List()",
 
@@ -561,6 +620,7 @@ GenerateBuilderMembers(io::Printer* printer) const {
     NULL);
 
   // int getRepeatedFieldCount()
+  WriteFieldDocComment(printer, descriptor_);
   PrintNestedBuilderFunction(printer,
     "$deprecation$public int get$capitalized_name$Count()",
 
@@ -570,6 +630,7 @@ GenerateBuilderMembers(io::Printer* printer) const {
     NULL);
 
   // Field getRepeatedField(int index)
+  WriteFieldDocComment(printer, descriptor_);
   PrintNestedBuilderFunction(printer,
     "$deprecation$public $type$ get$capitalized_name$(int index)",
 
@@ -580,6 +641,7 @@ GenerateBuilderMembers(io::Printer* printer) const {
     NULL);
 
   // Builder setRepeatedField(int index, Field value)
+  WriteFieldDocComment(printer, descriptor_);
   PrintNestedBuilderFunction(printer,
     "$deprecation$public Builder set$capitalized_name$(\n"
     "    int index, $type$ value)",
@@ -593,6 +655,7 @@ GenerateBuilderMembers(io::Printer* printer) const {
     "return this;\n");
 
   // Builder setRepeatedField(int index, Field.Builder builderForValue)
+  WriteFieldDocComment(printer, descriptor_);
   PrintNestedBuilderFunction(printer,
     "$deprecation$public Builder set$capitalized_name$(\n"
     "    int index, $type$.Builder builderForValue)",
@@ -606,6 +669,7 @@ GenerateBuilderMembers(io::Printer* printer) const {
     "return this;\n");
 
   // Builder addRepeatedField(Field value)
+  WriteFieldDocComment(printer, descriptor_);
   PrintNestedBuilderFunction(printer,
     "$deprecation$public Builder add$capitalized_name$($type$ value)",
 
@@ -622,6 +686,7 @@ GenerateBuilderMembers(io::Printer* printer) const {
     "return this;\n");
 
   // Builder addRepeatedField(int index, Field value)
+  WriteFieldDocComment(printer, descriptor_);
   PrintNestedBuilderFunction(printer,
     "$deprecation$public Builder add$capitalized_name$(\n"
     "    int index, $type$ value)",
@@ -638,6 +703,7 @@ GenerateBuilderMembers(io::Printer* printer) const {
     "return this;\n");
 
   // Builder addRepeatedField(Field.Builder builderForValue)
+  WriteFieldDocComment(printer, descriptor_);
   PrintNestedBuilderFunction(printer,
     "$deprecation$public Builder add$capitalized_name$(\n"
     "    $type$.Builder builderForValue)",
@@ -651,6 +717,7 @@ GenerateBuilderMembers(io::Printer* printer) const {
     "return this;\n");
 
   // Builder addRepeatedField(int index, Field.Builder builderForValue)
+  WriteFieldDocComment(printer, descriptor_);
   PrintNestedBuilderFunction(printer,
     "$deprecation$public Builder add$capitalized_name$(\n"
     "    int index, $type$.Builder builderForValue)",
@@ -664,6 +731,7 @@ GenerateBuilderMembers(io::Printer* printer) const {
     "return this;\n");
 
   // Builder addAllRepeatedField(Iterable<Field> values)
+  WriteFieldDocComment(printer, descriptor_);
   PrintNestedBuilderFunction(printer,
     "$deprecation$public Builder addAll$capitalized_name$(\n"
     "    java.lang.Iterable<? extends $type$> values)",
@@ -677,6 +745,7 @@ GenerateBuilderMembers(io::Printer* printer) const {
     "return this;\n");
 
   // Builder clearAllRepeatedField()
+  WriteFieldDocComment(printer, descriptor_);
   PrintNestedBuilderFunction(printer,
     "$deprecation$public Builder clear$capitalized_name$()",
 
@@ -689,6 +758,7 @@ GenerateBuilderMembers(io::Printer* printer) const {
     "return this;\n");
 
   // Builder removeRepeatedField(int index)
+  WriteFieldDocComment(printer, descriptor_);
   PrintNestedBuilderFunction(printer,
     "$deprecation$public Builder remove$capitalized_name$(int index)",
 
@@ -701,12 +771,15 @@ GenerateBuilderMembers(io::Printer* printer) const {
     "return this;\n");
 
   if (HasNestedBuilders(descriptor_->containing_type())) {
+    WriteFieldDocComment(printer, descriptor_);
     printer->Print(variables_,
       "$deprecation$public $type$.Builder get$capitalized_name$Builder(\n"
       "    int index) {\n"
       "  return get$capitalized_name$FieldBuilder().getBuilder(index);\n"
-      "}\n"
+      "}\n");
 
+    WriteFieldDocComment(printer, descriptor_);
+        printer->Print(variables_,
       "$deprecation$public $type$OrBuilder get$capitalized_name$OrBuilder(\n"
       "    int index) {\n"
       "  if ($name$Builder_ == null) {\n"
@@ -714,8 +787,10 @@ GenerateBuilderMembers(io::Printer* printer) const {
       "  } else {\n"
       "    return $name$Builder_.getMessageOrBuilder(index);\n"
       "  }\n"
-      "}\n"
+      "}\n");
 
+    WriteFieldDocComment(printer, descriptor_);
+        printer->Print(variables_,
       "$deprecation$public java.util.List<? extends $type$OrBuilder> \n"
       "     get$capitalized_name$OrBuilderList() {\n"
       "  if ($name$Builder_ != null) {\n"
@@ -723,17 +798,23 @@ GenerateBuilderMembers(io::Printer* printer) const {
       "  } else {\n"
       "    return java.util.Collections.unmodifiableList($name$_);\n"
       "  }\n"
-      "}\n"
+      "}\n");
 
+    WriteFieldDocComment(printer, descriptor_);
+        printer->Print(variables_,
       "$deprecation$public $type$.Builder add$capitalized_name$Builder() {\n"
       "  return get$capitalized_name$FieldBuilder().addBuilder(\n"
       "      $type$.getDefaultInstance());\n"
-      "}\n"
+      "}\n");
+    WriteFieldDocComment(printer, descriptor_);
+        printer->Print(variables_,
       "$deprecation$public $type$.Builder add$capitalized_name$Builder(\n"
       "    int index) {\n"
       "  return get$capitalized_name$FieldBuilder().addBuilder(\n"
       "      index, $type$.getDefaultInstance());\n"
-      "}\n"
+      "}\n");
+    WriteFieldDocComment(printer, descriptor_);
+        printer->Print(variables_,
       "$deprecation$public java.util.List<$type$.Builder> \n"
       "     get$capitalized_name$BuilderList() {\n"
       "  return get$capitalized_name$FieldBuilder().getBuilderList();\n"
@@ -827,18 +908,27 @@ GenerateBuildingCode(io::Printer* printer) const {
 void RepeatedMessageFieldGenerator::
 GenerateParsingCode(io::Printer* printer) const {
   printer->Print(variables_,
-    "$type$.Builder subBuilder = $type$.newBuilder();\n");
+    "if (!$get_mutable_bit_parser$) {\n"
+    "  $name$_ = new java.util.ArrayList<$type$>();\n"
+    "  $set_mutable_bit_parser$;\n"
+    "}\n");
 
   if (GetType(descriptor_) == FieldDescriptor::TYPE_GROUP) {
     printer->Print(variables_,
-      "input.readGroup($number$, subBuilder, extensionRegistry);\n");
+      "$name$_.add(input.readGroup($number$, $type$.PARSER,\n"
+      "    extensionRegistry));\n");
   } else {
     printer->Print(variables_,
-      "input.readMessage(subBuilder, extensionRegistry);\n");
+      "$name$_.add(input.readMessage($type$.PARSER, extensionRegistry));\n");
   }
+}
 
+void RepeatedMessageFieldGenerator::
+GenerateParsingDoneCode(io::Printer* printer) const {
   printer->Print(variables_,
-    "add$capitalized_name$(subBuilder.buildPartial());\n");
+    "if ($get_mutable_bit_parser$) {\n"
+    "  $name$_ = java.util.Collections.unmodifiableList($name$_);\n"
+    "}\n");
 }
 
 void RepeatedMessageFieldGenerator::
diff --git a/src/google/protobuf/compiler/java/java_message_field.h b/src/google/protobuf/compiler/java/java_message_field.h
index 2efbcd97..5c8078a1 100644
--- a/src/google/protobuf/compiler/java/java_message_field.h
+++ b/src/google/protobuf/compiler/java/java_message_field.h
@@ -61,6 +61,7 @@ class MessageFieldGenerator : public FieldGenerator {
   void GenerateMergingCode(io::Printer* printer) const;
   void GenerateBuildingCode(io::Printer* printer) const;
   void GenerateParsingCode(io::Printer* printer) const;
+  void GenerateParsingDoneCode(io::Printer* printer) const;
   void GenerateSerializationCode(io::Printer* printer) const;
   void GenerateSerializedSizeCode(io::Printer* printer) const;
   void GenerateFieldBuilderInitializationCode(io::Printer* printer) const;
@@ -102,6 +103,7 @@ class RepeatedMessageFieldGenerator : public FieldGenerator {
   void GenerateMergingCode(io::Printer* printer) const;
   void GenerateBuildingCode(io::Printer* printer) const;
   void GenerateParsingCode(io::Printer* printer) const;
+  void GenerateParsingDoneCode(io::Printer* printer) const;
   void GenerateSerializationCode(io::Printer* printer) const;
   void GenerateSerializedSizeCode(io::Printer* printer) const;
   void GenerateFieldBuilderInitializationCode(io::Printer* printer) const;
diff --git a/src/google/protobuf/compiler/java/java_primitive_field.cc b/src/google/protobuf/compiler/java/java_primitive_field.cc
index 712e047a..0140e23f 100644
--- a/src/google/protobuf/compiler/java/java_primitive_field.cc
+++ b/src/google/protobuf/compiler/java/java_primitive_field.cc
@@ -36,6 +36,7 @@
 #include <string>
 
 #include <google/protobuf/compiler/java/java_primitive_field.h>
+#include <google/protobuf/compiler/java/java_doc_comment.h>
 #include <google/protobuf/stubs/common.h>
 #include <google/protobuf/compiler/java/java_helpers.h>
 #include <google/protobuf/io/printer.h>
@@ -197,6 +198,7 @@ void SetPrimitiveVariables(const FieldDescriptor* descriptor,
 
   // For singular messages and builders, one bit is used for the hasField bit.
   (*variables)["get_has_field_bit_message"] = GenerateGetBit(messageBitIndex);
+  (*variables)["set_has_field_bit_message"] = GenerateSetBit(messageBitIndex);
 
   (*variables)["get_has_field_bit_builder"] = GenerateGetBit(builderBitIndex);
   (*variables)["set_has_field_bit_builder"] = GenerateSetBit(builderBitIndex);
@@ -208,6 +210,13 @@ void SetPrimitiveVariables(const FieldDescriptor* descriptor,
   (*variables)["set_mutable_bit_builder"] = GenerateSetBit(builderBitIndex);
   (*variables)["clear_mutable_bit_builder"] = GenerateClearBit(builderBitIndex);
 
+  // For repeated fields, one bit is used for whether the array is immutable
+  // in the parsing constructor.
+  (*variables)["get_mutable_bit_parser"] =
+      GenerateGetBitMutableLocal(builderBitIndex);
+  (*variables)["set_mutable_bit_parser"] =
+      GenerateSetBitMutableLocal(builderBitIndex);
+
   (*variables)["get_has_field_bit_from_local"] =
       GenerateGetBitFromLocal(builderBitIndex);
   (*variables)["set_has_field_bit_to_local"] =
@@ -240,19 +249,26 @@ int PrimitiveFieldGenerator::GetNumBitsForBuilder() const {
 
 void PrimitiveFieldGenerator::
 GenerateInterfaceMembers(io::Printer* printer) const {
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
+    "$deprecation$boolean has$capitalized_name$();\n");
+  WriteFieldDocComment(printer, descriptor_);
   printer->Print(variables_,
-    "$deprecation$boolean has$capitalized_name$();\n"
     "$deprecation$$type$ get$capitalized_name$();\n");
 }
 
 void PrimitiveFieldGenerator::
 GenerateMembers(io::Printer* printer) const {
   printer->Print(variables_,
-    "private $field_type$ $name$_;\n"
+    "private $field_type$ $name$_;\n");
+
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public boolean has$capitalized_name$() {\n"
     "  return $get_has_field_bit_message$;\n"
     "}\n");
 
+  WriteFieldDocComment(printer, descriptor_);
   printer->Print(variables_,
     "$deprecation$public $type$ get$capitalized_name$() {\n"
     "  return $name$_;\n"
@@ -262,16 +278,21 @@ GenerateMembers(io::Printer* printer) const {
 void PrimitiveFieldGenerator::
 GenerateBuilderMembers(io::Printer* printer) const {
   printer->Print(variables_,
-    "private $field_type$ $name$_ $default_init$;\n"
+    "private $field_type$ $name$_ $default_init$;\n");
+
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public boolean has$capitalized_name$() {\n"
     "  return $get_has_field_bit_builder$;\n"
     "}\n");
 
+  WriteFieldDocComment(printer, descriptor_);
   printer->Print(variables_,
     "$deprecation$public $type$ get$capitalized_name$() {\n"
     "  return $name$_;\n"
     "}\n");
 
+  WriteFieldDocComment(printer, descriptor_);
   printer->Print(variables_,
     "$deprecation$public Builder set$capitalized_name$($type$ value) {\n"
     "$null_check$"
@@ -279,7 +300,10 @@ GenerateBuilderMembers(io::Printer* printer) const {
     "  $name$_ = value;\n"
     "  $on_changed$\n"
     "  return this;\n"
-    "}\n"
+    "}\n");
+
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public Builder clear$capitalized_name$() {\n"
     "  $clear_has_field_bit_builder$;\n");
   JavaType type = GetJavaType(descriptor_);
@@ -335,11 +359,16 @@ GenerateBuildingCode(io::Printer* printer) const {
 void PrimitiveFieldGenerator::
 GenerateParsingCode(io::Printer* printer) const {
   printer->Print(variables_,
-    "$set_has_field_bit_builder$;\n"
+    "$set_has_field_bit_message$;\n"
     "$name$_ = input.read$capitalized_type$();\n");
 }
 
 void PrimitiveFieldGenerator::
+GenerateParsingDoneCode(io::Printer* printer) const {
+  // noop for primitives.
+}
+
+void PrimitiveFieldGenerator::
 GenerateSerializationCode(io::Printer* printer) const {
   printer->Print(variables_,
     "if ($get_has_field_bit_message$) {\n"
@@ -468,9 +497,14 @@ int RepeatedPrimitiveFieldGenerator::GetNumBitsForBuilder() const {
 
 void RepeatedPrimitiveFieldGenerator::
 GenerateInterfaceMembers(io::Printer* printer) const {
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
+    "$deprecation$java.util.List<$boxed_type$> get$capitalized_name$List();\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
+    "$deprecation$int get$capitalized_name$Count();\n");
+  WriteFieldDocComment(printer, descriptor_);
   printer->Print(variables_,
-    "$deprecation$java.util.List<$boxed_type$> get$capitalized_name$List();\n"
-    "$deprecation$int get$capitalized_name$Count();\n"
     "$deprecation$$type$ get$capitalized_name$(int index);\n");
 }
 
@@ -478,14 +512,20 @@ GenerateInterfaceMembers(io::Printer* printer) const {
 void RepeatedPrimitiveFieldGenerator::
 GenerateMembers(io::Printer* printer) const {
   printer->Print(variables_,
-    "private $field_list_type$ $name$_;\n"
+    "private $field_list_type$ $name$_;\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public java.util.List<$boxed_type$>\n"
     "    get$capitalized_name$List() {\n"
     "  return $name$_;\n"   // note:  unmodifiable list
-    "}\n"
+    "}\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public int get$capitalized_name$Count() {\n"
     "  return $name$_.size();\n"
-    "}\n"
+    "}\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public $type$ get$capitalized_name$(int index) {\n"
     "  return $name$_.get(index);\n"
     "}\n");
@@ -523,17 +563,24 @@ GenerateBuilderMembers(io::Printer* printer) const {
     //   could hold on to the returned list and modify it after the message
     //   has been built, thus mutating the message which is supposed to be
     //   immutable.
+  WriteFieldDocComment(printer, descriptor_);
   printer->Print(variables_,
     "$deprecation$public java.util.List<$boxed_type$>\n"
     "    get$capitalized_name$List() {\n"
     "  return java.util.Collections.unmodifiableList($name$_);\n"
-    "}\n"
+    "}\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public int get$capitalized_name$Count() {\n"
     "  return $name$_.size();\n"
-    "}\n"
+    "}\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public $type$ get$capitalized_name$(int index) {\n"
     "  return $name$_.get(index);\n"
-    "}\n"
+    "}\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public Builder set$capitalized_name$(\n"
     "    int index, $type$ value) {\n"
     "$null_check$"
@@ -541,21 +588,27 @@ GenerateBuilderMembers(io::Printer* printer) const {
     "  $name$_.set(index, value);\n"
     "  $on_changed$\n"
     "  return this;\n"
-    "}\n"
+    "}\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public Builder add$capitalized_name$($type$ value) {\n"
     "$null_check$"
     "  ensure$capitalized_name$IsMutable();\n"
     "  $name$_.add(value);\n"
     "  $on_changed$\n"
     "  return this;\n"
-    "}\n"
+    "}\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public Builder addAll$capitalized_name$(\n"
     "    java.lang.Iterable<? extends $boxed_type$> values) {\n"
     "  ensure$capitalized_name$IsMutable();\n"
     "  super.addAll(values, $name$_);\n"
     "  $on_changed$\n"
     "  return this;\n"
-    "}\n"
+    "}\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public Builder clear$capitalized_name$() {\n"
     "  $name$_ = $empty_list$;\n"
     "  $clear_mutable_bit_builder$;\n"
@@ -616,7 +669,10 @@ GenerateBuildingCode(io::Printer* printer) const {
 void RepeatedPrimitiveFieldGenerator::
 GenerateParsingCode(io::Printer* printer) const {
   printer->Print(variables_,
-    "ensure$capitalized_name$IsMutable();\n"
+    "if (!$get_mutable_bit_parser$) {\n"
+    "  $name$_ = new java.util.ArrayList<$boxed_type$>();\n"
+    "  $set_mutable_bit_parser$;\n"
+    "}\n"
     "$name$_.add(input.read$capitalized_type$());\n");
 }
 
@@ -625,13 +681,25 @@ GenerateParsingCodeFromPacked(io::Printer* printer) const {
   printer->Print(variables_,
     "int length = input.readRawVarint32();\n"
     "int limit = input.pushLimit(length);\n"
+    "if (!$get_mutable_bit_parser$ && input.getBytesUntilLimit() > 0) {\n"
+    "  $name$_ = new java.util.ArrayList<$boxed_type$>();\n"
+    "  $set_mutable_bit_parser$;\n"
+    "}\n"
     "while (input.getBytesUntilLimit() > 0) {\n"
-    "  add$capitalized_name$(input.read$capitalized_type$());\n"
+    "  $name$_.add(input.read$capitalized_type$());\n"
     "}\n"
     "input.popLimit(limit);\n");
 }
 
 void RepeatedPrimitiveFieldGenerator::
+GenerateParsingDoneCode(io::Printer* printer) const {
+  printer->Print(variables_,
+    "if ($get_mutable_bit_parser$) {\n"
+    "  $name$_ = java.util.Collections.unmodifiableList($name$_);\n"
+    "}\n");
+}
+
+void RepeatedPrimitiveFieldGenerator::
 GenerateSerializationCode(io::Printer* printer) const {
   if (descriptor_->options().packed()) {
     printer->Print(variables_,
diff --git a/src/google/protobuf/compiler/java/java_primitive_field.h b/src/google/protobuf/compiler/java/java_primitive_field.h
index 7900fac5..1b5b6d95 100644
--- a/src/google/protobuf/compiler/java/java_primitive_field.h
+++ b/src/google/protobuf/compiler/java/java_primitive_field.h
@@ -61,6 +61,7 @@ class PrimitiveFieldGenerator : public FieldGenerator {
   void GenerateMergingCode(io::Printer* printer) const;
   void GenerateBuildingCode(io::Printer* printer) const;
   void GenerateParsingCode(io::Printer* printer) const;
+  void GenerateParsingDoneCode(io::Printer* printer) const;
   void GenerateSerializationCode(io::Printer* printer) const;
   void GenerateSerializedSizeCode(io::Printer* printer) const;
   void GenerateFieldBuilderInitializationCode(io::Printer* printer) const;
@@ -96,6 +97,7 @@ class RepeatedPrimitiveFieldGenerator : public FieldGenerator {
   void GenerateBuildingCode(io::Printer* printer) const;
   void GenerateParsingCode(io::Printer* printer) const;
   void GenerateParsingCodeFromPacked(io::Printer* printer) const;
+  void GenerateParsingDoneCode(io::Printer* printer) const;
   void GenerateSerializationCode(io::Printer* printer) const;
   void GenerateSerializedSizeCode(io::Printer* printer) const;
   void GenerateFieldBuilderInitializationCode(io::Printer* printer) const;
diff --git a/src/google/protobuf/compiler/java/java_service.cc b/src/google/protobuf/compiler/java/java_service.cc
index 1ae4f461..bbd24806 100644
--- a/src/google/protobuf/compiler/java/java_service.cc
+++ b/src/google/protobuf/compiler/java/java_service.cc
@@ -33,6 +33,7 @@
 //  Sanjay Ghemawat, Jeff Dean, and others.
 
 #include <google/protobuf/compiler/java/java_service.h>
+#include <google/protobuf/compiler/java/java_doc_comment.h>
 #include <google/protobuf/compiler/java/java_helpers.h>
 #include <google/protobuf/io/printer.h>
 #include <google/protobuf/descriptor.pb.h>
@@ -50,6 +51,7 @@ ServiceGenerator::~ServiceGenerator() {}
 
 void ServiceGenerator::Generate(io::Printer* printer) {
   bool is_own_file = descriptor_->file()->options().java_multiple_files();
+  WriteServiceDocComment(printer, descriptor_);
   printer->Print(
     "public $static$ abstract class $classname$\n"
     "    implements com.google.protobuf.Service {\n",
@@ -157,6 +159,7 @@ void ServiceGenerator::GenerateNewReflectiveBlockingServiceMethod(
 void ServiceGenerator::GenerateAbstractMethods(io::Printer* printer) {
   for (int i = 0; i < descriptor_->method_count(); i++) {
     const MethodDescriptor* method = descriptor_->method(i);
+    WriteMethodDocComment(printer, method);
     GenerateMethodSignature(printer, method, IS_ABSTRACT);
     printer->Print(";\n\n");
   }
diff --git a/src/google/protobuf/compiler/java/java_string_field.cc b/src/google/protobuf/compiler/java/java_string_field.cc
index 222285bd..4815663b 100644
--- a/src/google/protobuf/compiler/java/java_string_field.cc
+++ b/src/google/protobuf/compiler/java/java_string_field.cc
@@ -37,6 +37,7 @@
 #include <string>
 
 #include <google/protobuf/compiler/java/java_string_field.h>
+#include <google/protobuf/compiler/java/java_doc_comment.h>
 #include <google/protobuf/stubs/common.h>
 #include <google/protobuf/compiler/java/java_helpers.h>
 #include <google/protobuf/io/printer.h>
@@ -85,6 +86,7 @@ void SetPrimitiveVariables(const FieldDescriptor* descriptor,
 
   // For singular messages and builders, one bit is used for the hasField bit.
   (*variables)["get_has_field_bit_message"] = GenerateGetBit(messageBitIndex);
+  (*variables)["set_has_field_bit_message"] = GenerateSetBit(messageBitIndex);
 
   (*variables)["get_has_field_bit_builder"] = GenerateGetBit(builderBitIndex);
   (*variables)["set_has_field_bit_builder"] = GenerateSetBit(builderBitIndex);
@@ -96,6 +98,13 @@ void SetPrimitiveVariables(const FieldDescriptor* descriptor,
   (*variables)["set_mutable_bit_builder"] = GenerateSetBit(builderBitIndex);
   (*variables)["clear_mutable_bit_builder"] = GenerateClearBit(builderBitIndex);
 
+  // For repeated fields, one bit is used for whether the array is immutable
+  // in the parsing constructor.
+  (*variables)["get_mutable_bit_parser"] =
+      GenerateGetBitMutableLocal(builderBitIndex);
+  (*variables)["set_mutable_bit_parser"] =
+      GenerateSetBitMutableLocal(builderBitIndex);
+
   (*variables)["get_has_field_bit_from_local"] =
       GenerateGetBitFromLocal(builderBitIndex);
   (*variables)["set_has_field_bit_to_local"] =
@@ -160,19 +169,29 @@ int StringFieldGenerator::GetNumBitsForBuilder() const {
 // UnmodifiableLazyStringList.
 void StringFieldGenerator::
 GenerateInterfaceMembers(io::Printer* printer) const {
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
+    "$deprecation$boolean has$capitalized_name$();\n");
+  WriteFieldDocComment(printer, descriptor_);
   printer->Print(variables_,
-    "$deprecation$boolean has$capitalized_name$();\n"
     "$deprecation$java.lang.String get$capitalized_name$();\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
+    "$deprecation$com.google.protobuf.ByteString\n"
+    "    get$capitalized_name$Bytes();\n");
 }
 
 void StringFieldGenerator::
 GenerateMembers(io::Printer* printer) const {
   printer->Print(variables_,
-    "private java.lang.Object $name$_;\n"
+    "private java.lang.Object $name$_;\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public boolean has$capitalized_name$() {\n"
     "  return $get_has_field_bit_message$;\n"
     "}\n");
 
+  WriteFieldDocComment(printer, descriptor_);
   printer->Print(variables_,
     "$deprecation$public java.lang.String get$capitalized_name$() {\n"
     "  java.lang.Object ref = $name$_;\n"
@@ -182,13 +201,16 @@ GenerateMembers(io::Printer* printer) const {
     "    com.google.protobuf.ByteString bs = \n"
     "        (com.google.protobuf.ByteString) ref;\n"
     "    java.lang.String s = bs.toStringUtf8();\n"
-    "    if (com.google.protobuf.Internal.isValidUtf8(bs)) {\n"
+    "    if (bs.isValidUtf8()) {\n"
     "      $name$_ = s;\n"
     "    }\n"
     "    return s;\n"
     "  }\n"
-    "}\n"
-    "private com.google.protobuf.ByteString get$capitalized_name$Bytes() {\n"
+    "}\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
+    "$deprecation$public com.google.protobuf.ByteString\n"
+    "    get$capitalized_name$Bytes() {\n"
     "  java.lang.Object ref = $name$_;\n"
     "  if (ref instanceof java.lang.String) {\n"
     "    com.google.protobuf.ByteString b = \n"
@@ -205,11 +227,14 @@ GenerateMembers(io::Printer* printer) const {
 void StringFieldGenerator::
 GenerateBuilderMembers(io::Printer* printer) const {
   printer->Print(variables_,
-    "private java.lang.Object $name$_ $default_init$;\n"
+    "private java.lang.Object $name$_ $default_init$;\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public boolean has$capitalized_name$() {\n"
     "  return $get_has_field_bit_builder$;\n"
     "}\n");
 
+  WriteFieldDocComment(printer, descriptor_);
   printer->Print(variables_,
     "$deprecation$public java.lang.String get$capitalized_name$() {\n"
     "  java.lang.Object ref = $name$_;\n"
@@ -223,6 +248,23 @@ GenerateBuilderMembers(io::Printer* printer) const {
     "  }\n"
     "}\n");
 
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
+    "$deprecation$public com.google.protobuf.ByteString\n"
+    "    get$capitalized_name$Bytes() {\n"
+    "  java.lang.Object ref = $name$_;\n"
+    "  if (ref instanceof String) {\n"
+    "    com.google.protobuf.ByteString b = \n"
+    "        com.google.protobuf.ByteString.copyFromUtf8(\n"
+    "            (java.lang.String) ref);\n"
+    "    $name$_ = b;\n"
+    "    return b;\n"
+    "  } else {\n"
+    "    return (com.google.protobuf.ByteString) ref;\n"
+    "  }\n"
+    "}\n");
+
+  WriteFieldDocComment(printer, descriptor_);
   printer->Print(variables_,
     "$deprecation$public Builder set$capitalized_name$(\n"
     "    java.lang.String value) {\n"
@@ -231,7 +273,9 @@ GenerateBuilderMembers(io::Printer* printer) const {
     "  $name$_ = value;\n"
     "  $on_changed$\n"
     "  return this;\n"
-    "}\n"
+    "}\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public Builder clear$capitalized_name$() {\n"
     "  $clear_has_field_bit_builder$;\n");
   // The default value is not a simple literal so we want to avoid executing
@@ -243,11 +287,15 @@ GenerateBuilderMembers(io::Printer* printer) const {
     "  return this;\n"
     "}\n");
 
+  WriteFieldDocComment(printer, descriptor_);
   printer->Print(variables_,
-    "void set$capitalized_name$(com.google.protobuf.ByteString value) {\n"
+    "$deprecation$public Builder set$capitalized_name$Bytes(\n"
+    "    com.google.protobuf.ByteString value) {\n"
+    "$null_check$"
     "  $set_has_field_bit_builder$;\n"
     "  $name$_ = value;\n"
     "  $on_changed$\n"
+    "  return this;\n"
     "}\n");
 }
 
@@ -270,9 +318,13 @@ GenerateBuilderClearCode(io::Printer* printer) const {
 
 void StringFieldGenerator::
 GenerateMergingCode(io::Printer* printer) const {
+  // Allow a slight breach of abstraction here in order to avoid forcing
+  // all string fields to Strings when copying fields from a Message.
   printer->Print(variables_,
     "if (other.has$capitalized_name$()) {\n"
-    "  set$capitalized_name$(other.get$capitalized_name$());\n"
+    "  $set_has_field_bit_builder$;\n"
+    "  $name$_ = other.$name$_;\n"
+    "  $on_changed$\n"
     "}\n");
 }
 
@@ -288,11 +340,16 @@ GenerateBuildingCode(io::Printer* printer) const {
 void StringFieldGenerator::
 GenerateParsingCode(io::Printer* printer) const {
   printer->Print(variables_,
-    "$set_has_field_bit_builder$;\n"
+    "$set_has_field_bit_message$;\n"
     "$name$_ = input.readBytes();\n");
 }
 
 void StringFieldGenerator::
+GenerateParsingDoneCode(io::Printer* printer) const {
+  // noop for strings.
+}
+
+void StringFieldGenerator::
 GenerateSerializationCode(io::Printer* printer) const {
   printer->Print(variables_,
     "if ($get_has_field_bit_message$) {\n"
@@ -353,28 +410,49 @@ int RepeatedStringFieldGenerator::GetNumBitsForBuilder() const {
 
 void RepeatedStringFieldGenerator::
 GenerateInterfaceMembers(io::Printer* printer) const {
+  WriteFieldDocComment(printer, descriptor_);
   printer->Print(variables_,
     "$deprecation$java.util.List<java.lang.String>\n"
-    "    get$capitalized_name$List();\n"
-    "$deprecation$int get$capitalized_name$Count();\n"
+    "get$capitalized_name$List();\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
+    "$deprecation$int get$capitalized_name$Count();\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$java.lang.String get$capitalized_name$(int index);\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
+    "$deprecation$com.google.protobuf.ByteString\n"
+    "    get$capitalized_name$Bytes(int index);\n");
 }
 
 
 void RepeatedStringFieldGenerator::
 GenerateMembers(io::Printer* printer) const {
   printer->Print(variables_,
-    "private com.google.protobuf.LazyStringList $name$_;\n"
+    "private com.google.protobuf.LazyStringList $name$_;\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public java.util.List<java.lang.String>\n"
     "    get$capitalized_name$List() {\n"
     "  return $name$_;\n"   // note:  unmodifiable list
-    "}\n"
+    "}\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public int get$capitalized_name$Count() {\n"
     "  return $name$_.size();\n"
-    "}\n"
+    "}\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public java.lang.String get$capitalized_name$(int index) {\n"
     "  return $name$_.get(index);\n"
     "}\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
+    "$deprecation$public com.google.protobuf.ByteString\n"
+    "    get$capitalized_name$Bytes(int index) {\n"
+    "  return $name$_.getByteString(index);\n"
+    "}\n");
 
   if (descriptor_->options().packed() &&
       HasGeneratedMethods(descriptor_->containing_type())) {
@@ -409,17 +487,30 @@ GenerateBuilderMembers(io::Printer* printer) const {
     //   could hold on to the returned list and modify it after the message
     //   has been built, thus mutating the message which is supposed to be
     //   immutable.
+  WriteFieldDocComment(printer, descriptor_);
   printer->Print(variables_,
     "$deprecation$public java.util.List<java.lang.String>\n"
     "    get$capitalized_name$List() {\n"
     "  return java.util.Collections.unmodifiableList($name$_);\n"
-    "}\n"
+    "}\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public int get$capitalized_name$Count() {\n"
     "  return $name$_.size();\n"
-    "}\n"
+    "}\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public java.lang.String get$capitalized_name$(int index) {\n"
     "  return $name$_.get(index);\n"
-    "}\n"
+    "}\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
+    "$deprecation$public com.google.protobuf.ByteString\n"
+    "    get$capitalized_name$Bytes(int index) {\n"
+    "  return $name$_.getByteString(index);\n"
+    "}\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public Builder set$capitalized_name$(\n"
     "    int index, java.lang.String value) {\n"
     "$null_check$"
@@ -427,7 +518,9 @@ GenerateBuilderMembers(io::Printer* printer) const {
     "  $name$_.set(index, value);\n"
     "  $on_changed$\n"
     "  return this;\n"
-    "}\n"
+    "}\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public Builder add$capitalized_name$(\n"
     "    java.lang.String value) {\n"
     "$null_check$"
@@ -435,14 +528,18 @@ GenerateBuilderMembers(io::Printer* printer) const {
     "  $name$_.add(value);\n"
     "  $on_changed$\n"
     "  return this;\n"
-    "}\n"
+    "}\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public Builder addAll$capitalized_name$(\n"
     "    java.lang.Iterable<java.lang.String> values) {\n"
     "  ensure$capitalized_name$IsMutable();\n"
     "  super.addAll(values, $name$_);\n"
     "  $on_changed$\n"
     "  return this;\n"
-    "}\n"
+    "}\n");
+  WriteFieldDocComment(printer, descriptor_);
+  printer->Print(variables_,
     "$deprecation$public Builder clear$capitalized_name$() {\n"
     "  $name$_ = $empty_list$;\n"
     "  $clear_mutable_bit_builder$;\n"
@@ -450,11 +547,15 @@ GenerateBuilderMembers(io::Printer* printer) const {
     "  return this;\n"
     "}\n");
 
+  WriteFieldDocComment(printer, descriptor_);
   printer->Print(variables_,
-    "void add$capitalized_name$(com.google.protobuf.ByteString value) {\n"
+    "$deprecation$public Builder add$capitalized_name$Bytes(\n"
+    "    com.google.protobuf.ByteString value) {\n"
+    "$null_check$"
     "  ensure$capitalized_name$IsMutable();\n"
     "  $name$_.add(value);\n"
     "  $on_changed$\n"
+    "  return this;\n"
     "}\n");
 }
 
@@ -512,7 +613,10 @@ GenerateBuildingCode(io::Printer* printer) const {
 void RepeatedStringFieldGenerator::
 GenerateParsingCode(io::Printer* printer) const {
   printer->Print(variables_,
-    "ensure$capitalized_name$IsMutable();\n"
+    "if (!$get_mutable_bit_parser$) {\n"
+    "  $name$_ = new com.google.protobuf.LazyStringArrayList();\n"
+    "  $set_mutable_bit_parser$;\n"
+    "}\n"
     "$name$_.add(input.readBytes());\n");
 }
 
@@ -521,13 +625,25 @@ GenerateParsingCodeFromPacked(io::Printer* printer) const {
   printer->Print(variables_,
     "int length = input.readRawVarint32();\n"
     "int limit = input.pushLimit(length);\n"
+    "if (!$get_mutable_bit_parser$ && input.getBytesUntilLimit() > 0) {\n"
+    "  $name$_ = new com.google.protobuf.LazyStringArrayList();\n"
+    "  $set_mutable_bit_parser$;\n"
+    "}\n"
     "while (input.getBytesUntilLimit() > 0) {\n"
-    "  add$capitalized_name$(input.read$capitalized_type$());\n"
+    "  $name$.add(input.read$capitalized_type$());\n"
     "}\n"
     "input.popLimit(limit);\n");
 }
 
 void RepeatedStringFieldGenerator::
+GenerateParsingDoneCode(io::Printer* printer) const {
+  printer->Print(variables_,
+    "if ($get_mutable_bit_parser$) {\n"
+    "  $name$_ = new com.google.protobuf.UnmodifiableLazyStringList($name$_);\n"
+    "}\n");
+}
+
+void RepeatedStringFieldGenerator::
 GenerateSerializationCode(io::Printer* printer) const {
   if (descriptor_->options().packed()) {
     printer->Print(variables_,
diff --git a/src/google/protobuf/compiler/java/java_string_field.h b/src/google/protobuf/compiler/java/java_string_field.h
index 8cb41469..4f7532f4 100644
--- a/src/google/protobuf/compiler/java/java_string_field.h
+++ b/src/google/protobuf/compiler/java/java_string_field.h
@@ -62,6 +62,7 @@ class StringFieldGenerator : public FieldGenerator {
   void GenerateMergingCode(io::Printer* printer) const;
   void GenerateBuildingCode(io::Printer* printer) const;
   void GenerateParsingCode(io::Printer* printer) const;
+  void GenerateParsingDoneCode(io::Printer* printer) const;
   void GenerateSerializationCode(io::Printer* printer) const;
   void GenerateSerializedSizeCode(io::Printer* printer) const;
   void GenerateFieldBuilderInitializationCode(io::Printer* printer) const;
@@ -96,6 +97,7 @@ class RepeatedStringFieldGenerator : public FieldGenerator {
   void GenerateBuildingCode(io::Printer* printer) const;
   void GenerateParsingCode(io::Printer* printer) const;
   void GenerateParsingCodeFromPacked(io::Printer* printer) const;
+  void GenerateParsingDoneCode(io::Printer* printer) const;
   void GenerateSerializationCode(io::Printer* printer) const;
   void GenerateSerializedSizeCode(io::Printer* printer) const;
   void GenerateFieldBuilderInitializationCode(io::Printer* printer) const;
diff --git a/src/google/protobuf/compiler/main.cc b/src/google/protobuf/compiler/main.cc
index d9b0c3f9..1afc5d61 100644
--- a/src/google/protobuf/compiler/main.cc
+++ b/src/google/protobuf/compiler/main.cc
@@ -43,7 +43,7 @@ int main(int argc, char* argv[]) {
 
   // Proto2 C++
   google::protobuf::compiler::cpp::CppGenerator cpp_generator;
-  cli.RegisterGenerator("--cpp_out", &cpp_generator,
+  cli.RegisterGenerator("--cpp_out", "--cpp_opt", &cpp_generator,
                         "Generate C++ header and source.");
 
   // Proto2 Java
diff --git a/src/google/protobuf/compiler/mock_code_generator.cc b/src/google/protobuf/compiler/mock_code_generator.cc
index 5b76af25..0e35ed19 100644
--- a/src/google/protobuf/compiler/mock_code_generator.cc
+++ b/src/google/protobuf/compiler/mock_code_generator.cc
@@ -33,13 +33,14 @@
 #include <google/protobuf/compiler/mock_code_generator.h>
 
 #include <google/protobuf/testing/file.h>
+#include <google/protobuf/descriptor.pb.h>
 #include <google/protobuf/descriptor.h>
 #include <google/protobuf/io/zero_copy_stream.h>
 #include <google/protobuf/io/printer.h>
 #include <google/protobuf/stubs/strutil.h>
 #include <google/protobuf/stubs/substitute.h>
 #include <gtest/gtest.h>
-#include <google/protobuf/stubs/stl_util-inl.h>
+#include <google/protobuf/stubs/stl_util.h>
 
 namespace google {
 namespace protobuf {
@@ -132,6 +133,15 @@ bool MockCodeGenerator::Generate(
       } else if (command == "Abort") {
         cerr << "Saw message type MockCodeGenerator_Abort." << endl;
         abort();
+      } else if (command == "HasSourceCodeInfo") {
+        FileDescriptorProto file_descriptor_proto;
+        file->CopySourceCodeInfoTo(&file_descriptor_proto);
+        bool has_source_code_info =
+            file_descriptor_proto.has_source_code_info() &&
+            file_descriptor_proto.source_code_info().location_size() > 0;
+        cerr << "Saw message type MockCodeGenerator_HasSourceCodeInfo: "
+             << has_source_code_info << "." << endl;
+        abort();
       } else {
         GOOGLE_LOG(FATAL) << "Unknown MockCodeGenerator command: " << command;
       }
diff --git a/src/google/protobuf/compiler/mock_code_generator.h b/src/google/protobuf/compiler/mock_code_generator.h
index 5c7942bd..506fd207 100644
--- a/src/google/protobuf/compiler/mock_code_generator.h
+++ b/src/google/protobuf/compiler/mock_code_generator.h
@@ -59,6 +59,10 @@ namespace compiler {
 //     MockCodeGenerator_Exit." to stderr and then calls exit(123).
 //   MockCodeGenerator_Abort:  Generate() prints "Saw message type
 //     MockCodeGenerator_Abort." to stderr and then calls abort().
+//   MockCodeGenerator_HasSourceCodeInfo:  Causes Generate() to abort after
+//     printing "Saw message type MockCodeGenerator_HasSourceCodeInfo: FOO." to
+//     stderr, where FOO is "1" if the supplied FileDescriptorProto has source
+//     code info, and "0" otherwise.
 class MockCodeGenerator : public CodeGenerator {
  public:
   MockCodeGenerator(const string& name);
diff --git a/src/google/protobuf/compiler/parser.cc b/src/google/protobuf/compiler/parser.cc
index 34317b1f..23aa01ce 100644
--- a/src/google/protobuf/compiler/parser.cc
+++ b/src/google/protobuf/compiler/parser.cc
@@ -174,6 +174,20 @@ bool Parser::ConsumeInteger(int* output, const char* error) {
   }
 }
 
+bool Parser::ConsumeSignedInteger(int* output, const char* error) {
+  bool is_negative = false;
+  uint64 max_value = kint32max;
+  if (TryConsume("-")) {
+    is_negative = true;
+    max_value += 1;
+  }
+  uint64 value = 0;
+  DO(ConsumeInteger64(max_value, &value, error));
+  if (is_negative) value *= -1;
+  *output = value;
+  return true;
+}
+
 bool Parser::ConsumeInteger64(uint64 max_value, uint64* output,
                               const char* error) {
   if (LookingAtType(io::Tokenizer::TYPE_INTEGER)) {
@@ -237,6 +251,35 @@ bool Parser::ConsumeString(string* output, const char* error) {
   }
 }
 
+bool Parser::TryConsumeEndOfDeclaration(const char* text,
+                                        const LocationRecorder* location) {
+  if (LookingAt(text)) {
+    string leading, trailing;
+    input_->NextWithComments(&trailing, NULL, &leading);
+
+    // Save the leading comments for next time, and recall the leading comments
+    // from last time.
+    leading.swap(upcoming_doc_comments_);
+
+    if (location != NULL) {
+      location->AttachComments(&leading, &trailing);
+    }
+    return true;
+  } else {
+    return false;
+  }
+}
+
+bool Parser::ConsumeEndOfDeclaration(const char* text,
+                                     const LocationRecorder* location) {
+  if (TryConsumeEndOfDeclaration(text, location)) {
+    return true;
+  } else {
+    AddError("Expected \"" + string(text) + "\".");
+    return false;
+  }
+}
+
 // -------------------------------------------------------------------
 
 void Parser::AddError(int line, int column, const string& error) {
@@ -315,6 +358,19 @@ void Parser::LocationRecorder::RecordLegacyLocation(const Message* descriptor,
   }
 }
 
+void Parser::LocationRecorder::AttachComments(
+    string* leading, string* trailing) const {
+  GOOGLE_CHECK(!location_->has_leading_comments());
+  GOOGLE_CHECK(!location_->has_trailing_comments());
+
+  if (!leading->empty()) {
+    location_->mutable_leading_comments()->swap(*leading);
+  }
+  if (!trailing->empty()) {
+    location_->mutable_trailing_comments()->swap(*trailing);
+  }
+}
+
 // -------------------------------------------------------------------
 
 void Parser::SkipStatement() {
@@ -322,7 +378,7 @@ void Parser::SkipStatement() {
     if (AtEnd()) {
       return;
     } else if (LookingAtType(io::Tokenizer::TYPE_SYMBOL)) {
-      if (TryConsume(";")) {
+      if (TryConsumeEndOfDeclaration(";", NULL)) {
         return;
       } else if (TryConsume("{")) {
         SkipRestOfBlock();
@@ -340,7 +396,7 @@ void Parser::SkipRestOfBlock() {
     if (AtEnd()) {
       return;
     } else if (LookingAtType(io::Tokenizer::TYPE_SYMBOL)) {
-      if (TryConsume("}")) {
+      if (TryConsumeEndOfDeclaration("}", NULL)) {
         return;
       } else if (TryConsume("{")) {
         SkipRestOfBlock();
@@ -366,7 +422,7 @@ bool Parser::Parse(io::Tokenizer* input, FileDescriptorProto* file) {
 
   if (LookingAtType(io::Tokenizer::TYPE_START)) {
     // Advance to first token.
-    input_->Next();
+    input_->NextWithComments(NULL, NULL, &upcoming_doc_comments_);
   }
 
   {
@@ -393,7 +449,7 @@ bool Parser::Parse(io::Tokenizer* input, FileDescriptorProto* file) {
 
         if (LookingAt("}")) {
           AddError("Unmatched \"}\".");
-          input_->Next();
+          input_->NextWithComments(NULL, NULL, &upcoming_doc_comments_);
         }
       }
     }
@@ -411,7 +467,7 @@ bool Parser::ParseSyntaxIdentifier() {
   io::Tokenizer::Token syntax_token = input_->current();
   string syntax;
   DO(ConsumeString(&syntax, "Expected syntax identifier."));
-  DO(Consume(";"));
+  DO(ConsumeEndOfDeclaration(";", NULL));
 
   syntax_identifier_ = syntax;
 
@@ -427,7 +483,7 @@ bool Parser::ParseSyntaxIdentifier() {
 
 bool Parser::ParseTopLevelStatement(FileDescriptorProto* file,
                                     const LocationRecorder& root_location) {
-  if (TryConsume(";")) {
+  if (TryConsumeEndOfDeclaration(";", NULL)) {
     // empty statement; ignore
     return true;
   } else if (LookingAt("message")) {
@@ -451,14 +507,16 @@ bool Parser::ParseTopLevelStatement(FileDescriptorProto* file,
                        FileDescriptorProto::kMessageTypeFieldNumber,
                        location);
   } else if (LookingAt("import")) {
-    int index = file->dependency_size();
-    return ParseImport(file->add_dependency(), root_location, index);
+    return ParseImport(file->mutable_dependency(),
+                       file->mutable_public_dependency(),
+                       file->mutable_weak_dependency(),
+                       root_location);
   } else if (LookingAt("package")) {
     return ParsePackage(file, root_location);
   } else if (LookingAt("option")) {
     LocationRecorder location(root_location,
         FileDescriptorProto::kOptionsFieldNumber);
-    return ParseOption(file->mutable_options(), location);
+    return ParseOption(file->mutable_options(), location, OPTION_STATEMENT);
   } else {
     AddError("Expected top-level statement (e.g. \"message\").");
     return false;
@@ -482,11 +540,45 @@ bool Parser::ParseMessageDefinition(DescriptorProto* message,
   return true;
 }
 
+namespace {
+
+const int kMaxExtensionRangeSentinel = -1;
+
+bool IsMessageSetWireFormatMessage(const DescriptorProto& message) {
+  const MessageOptions& options = message.options();
+  for (int i = 0; i < options.uninterpreted_option_size(); ++i) {
+    const UninterpretedOption& uninterpreted = options.uninterpreted_option(i);
+    if (uninterpreted.name_size() == 1 &&
+        uninterpreted.name(0).name_part() == "message_set_wire_format" &&
+        uninterpreted.identifier_value() == "true") {
+      return true;
+    }
+  }
+  return false;
+}
+
+// Modifies any extension ranges that specified 'max' as the end of the
+// extension range, and sets them to the type-specific maximum. The actual max
+// tag number can only be determined after all options have been parsed.
+void AdjustExtensionRangesWithMaxEndNumber(DescriptorProto* message) {
+  const bool is_message_set = IsMessageSetWireFormatMessage(*message);
+  const int max_extension_number = is_message_set ?
+      kint32max :
+      FieldDescriptor::kMaxNumber + 1;
+  for (int i = 0; i < message->extension_range_size(); ++i) {
+    if (message->extension_range(i).end() == kMaxExtensionRangeSentinel) {
+      message->mutable_extension_range(i)->set_end(max_extension_number);
+    }
+  }
+}
+
+}  // namespace
+
 bool Parser::ParseMessageBlock(DescriptorProto* message,
                                const LocationRecorder& message_location) {
-  DO(Consume("{"));
+  DO(ConsumeEndOfDeclaration("{", &message_location));
 
-  while (!TryConsume("}")) {
+  while (!TryConsumeEndOfDeclaration("}", NULL)) {
     if (AtEnd()) {
       AddError("Reached end of input in message definition (missing '}').");
       return false;
@@ -499,12 +591,15 @@ bool Parser::ParseMessageBlock(DescriptorProto* message,
     }
   }
 
+  if (message->extension_range_size() > 0) {
+    AdjustExtensionRangesWithMaxEndNumber(message);
+  }
   return true;
 }
 
 bool Parser::ParseMessageStatement(DescriptorProto* message,
                                    const LocationRecorder& message_location) {
-  if (TryConsume(";")) {
+  if (TryConsumeEndOfDeclaration(";", NULL)) {
     // empty statement; ignore
     return true;
   } else if (LookingAt("message")) {
@@ -532,7 +627,7 @@ bool Parser::ParseMessageStatement(DescriptorProto* message,
   } else if (LookingAt("option")) {
     LocationRecorder location(message_location,
                               DescriptorProto::kOptionsFieldNumber);
-    return ParseOption(message->mutable_options(), location);
+    return ParseOption(message->mutable_options(), location, OPTION_STATEMENT);
   } else {
     LocationRecorder location(message_location,
                               DescriptorProto::kFieldFieldNumber,
@@ -647,7 +742,7 @@ bool Parser::ParseMessageField(FieldDescriptorProto* field,
       return false;
     }
   } else {
-    DO(Consume(";"));
+    DO(ConsumeEndOfDeclaration(";", &field_location));
   }
 
   return true;
@@ -669,7 +764,7 @@ bool Parser::ParseFieldOptions(FieldDescriptorProto* field,
       // the default value is not actually an option.
       DO(ParseDefaultAssignment(field, field_location));
     } else {
-      DO(ParseOptionAssignment(field->mutable_options(), location));
+      DO(ParseOption(field->mutable_options(), location, OPTION_ASSIGNMENT));
     }
   } while (TryConsume(","));
 
@@ -835,6 +930,8 @@ bool Parser::ParseOptionNamePart(UninterpretedOption* uninterpreted_option,
 
 bool Parser::ParseUninterpretedBlock(string* value) {
   // Note that enclosing braces are not added to *value.
+  // We do NOT use ConsumeEndOfStatement for this brace because it's delimiting
+  // an expression, not a block of statements.
   DO(Consume("{"));
   int brace_depth = 1;
   while (!AtEnd()) {
@@ -858,8 +955,9 @@ bool Parser::ParseUninterpretedBlock(string* value) {
 
 // We don't interpret the option here. Instead we store it in an
 // UninterpretedOption, to be interpreted later.
-bool Parser::ParseOptionAssignment(Message* options,
-                                   const LocationRecorder& options_location) {
+bool Parser::ParseOption(Message* options,
+                         const LocationRecorder& options_location,
+                         OptionStyle style) {
   // Create an entry in the uninterpreted_option field.
   const FieldDescriptor* uninterpreted_option_field = options->GetDescriptor()->
       FindFieldByName("uninterpreted_option");
@@ -872,6 +970,10 @@ bool Parser::ParseOptionAssignment(Message* options,
       options_location, uninterpreted_option_field->number(),
       reflection->FieldSize(*options, uninterpreted_option_field));
 
+  if (style == OPTION_STATEMENT) {
+    DO(Consume("option"));
+  }
+
   UninterpretedOption* uninterpreted_option = down_cast<UninterpretedOption*>(
       options->GetReflection()->AddMessage(options,
                                            uninterpreted_option_field));
@@ -899,82 +1001,91 @@ bool Parser::ParseOptionAssignment(Message* options,
 
   DO(Consume("="));
 
-  LocationRecorder value_location(location);
-  value_location.RecordLegacyLocation(
-      uninterpreted_option, DescriptorPool::ErrorCollector::OPTION_VALUE);
-
-  // All values are a single token, except for negative numbers, which consist
-  // of a single '-' symbol, followed by a positive number.
-  bool is_negative = TryConsume("-");
+  {
+    LocationRecorder value_location(location);
+    value_location.RecordLegacyLocation(
+        uninterpreted_option, DescriptorPool::ErrorCollector::OPTION_VALUE);
 
-  switch (input_->current().type) {
-    case io::Tokenizer::TYPE_START:
-      GOOGLE_LOG(FATAL) << "Trying to read value before any tokens have been read.";
-      return false;
+    // All values are a single token, except for negative numbers, which consist
+    // of a single '-' symbol, followed by a positive number.
+    bool is_negative = TryConsume("-");
 
-    case io::Tokenizer::TYPE_END:
-      AddError("Unexpected end of stream while parsing option value.");
-      return false;
+    switch (input_->current().type) {
+      case io::Tokenizer::TYPE_START:
+        GOOGLE_LOG(FATAL) << "Trying to read value before any tokens have been read.";
+        return false;
 
-    case io::Tokenizer::TYPE_IDENTIFIER: {
-      value_location.AddPath(UninterpretedOption::kIdentifierValueFieldNumber);
-      if (is_negative) {
-        AddError("Invalid '-' symbol before identifier.");
+      case io::Tokenizer::TYPE_END:
+        AddError("Unexpected end of stream while parsing option value.");
         return false;
-      }
-      string value;
-      DO(ConsumeIdentifier(&value, "Expected identifier."));
-      uninterpreted_option->set_identifier_value(value);
-      break;
-    }
 
-    case io::Tokenizer::TYPE_INTEGER: {
-      uint64 value;
-      uint64 max_value =
-          is_negative ? static_cast<uint64>(kint64max) + 1 : kuint64max;
-      DO(ConsumeInteger64(max_value, &value, "Expected integer."));
-      if (is_negative) {
+      case io::Tokenizer::TYPE_IDENTIFIER: {
         value_location.AddPath(
-            UninterpretedOption::kNegativeIntValueFieldNumber);
-        uninterpreted_option->set_negative_int_value(-static_cast<int64>(value));
-      } else {
-        value_location.AddPath(
-            UninterpretedOption::kPositiveIntValueFieldNumber);
-        uninterpreted_option->set_positive_int_value(value);
+            UninterpretedOption::kIdentifierValueFieldNumber);
+        if (is_negative) {
+          AddError("Invalid '-' symbol before identifier.");
+          return false;
+        }
+        string value;
+        DO(ConsumeIdentifier(&value, "Expected identifier."));
+        uninterpreted_option->set_identifier_value(value);
+        break;
       }
-      break;
-    }
 
-    case io::Tokenizer::TYPE_FLOAT: {
-      value_location.AddPath(UninterpretedOption::kDoubleValueFieldNumber);
-      double value;
-      DO(ConsumeNumber(&value, "Expected number."));
-      uninterpreted_option->set_double_value(is_negative ? -value : value);
-      break;
-    }
+      case io::Tokenizer::TYPE_INTEGER: {
+        uint64 value;
+        uint64 max_value =
+            is_negative ? static_cast<uint64>(kint64max) + 1 : kuint64max;
+        DO(ConsumeInteger64(max_value, &value, "Expected integer."));
+        if (is_negative) {
+          value_location.AddPath(
+              UninterpretedOption::kNegativeIntValueFieldNumber);
+          uninterpreted_option->set_negative_int_value(
+              -static_cast<int64>(value));
+        } else {
+          value_location.AddPath(
+              UninterpretedOption::kPositiveIntValueFieldNumber);
+          uninterpreted_option->set_positive_int_value(value);
+        }
+        break;
+      }
 
-    case io::Tokenizer::TYPE_STRING: {
-      value_location.AddPath(UninterpretedOption::kStringValueFieldNumber);
-      if (is_negative) {
-        AddError("Invalid '-' symbol before string.");
-        return false;
+      case io::Tokenizer::TYPE_FLOAT: {
+        value_location.AddPath(UninterpretedOption::kDoubleValueFieldNumber);
+        double value;
+        DO(ConsumeNumber(&value, "Expected number."));
+        uninterpreted_option->set_double_value(is_negative ? -value : value);
+        break;
       }
-      string value;
-      DO(ConsumeString(&value, "Expected string."));
-      uninterpreted_option->set_string_value(value);
-      break;
-    }
 
-    case io::Tokenizer::TYPE_SYMBOL:
-      if (LookingAt("{")) {
-        value_location.AddPath(UninterpretedOption::kAggregateValueFieldNumber);
-        DO(ParseUninterpretedBlock(
-            uninterpreted_option->mutable_aggregate_value()));
-      } else {
-        AddError("Expected option value.");
-        return false;
+      case io::Tokenizer::TYPE_STRING: {
+        value_location.AddPath(UninterpretedOption::kStringValueFieldNumber);
+        if (is_negative) {
+          AddError("Invalid '-' symbol before string.");
+          return false;
+        }
+        string value;
+        DO(ConsumeString(&value, "Expected string."));
+        uninterpreted_option->set_string_value(value);
+        break;
       }
-      break;
+
+      case io::Tokenizer::TYPE_SYMBOL:
+        if (LookingAt("{")) {
+          value_location.AddPath(
+              UninterpretedOption::kAggregateValueFieldNumber);
+          DO(ParseUninterpretedBlock(
+              uninterpreted_option->mutable_aggregate_value()));
+        } else {
+          AddError("Expected option value.");
+          return false;
+        }
+        break;
+    }
+  }
+
+  if (style == OPTION_STATEMENT) {
+    DO(ConsumeEndOfDeclaration(";", &location));
   }
 
   return true;
@@ -1008,7 +1119,10 @@ bool Parser::ParseExtensions(DescriptorProto* message,
       LocationRecorder end_location(
           location, DescriptorProto::ExtensionRange::kEndFieldNumber);
       if (TryConsume("max")) {
-        end = FieldDescriptor::kMaxNumber;
+        // Set to the sentinel value - 1 since we increment the value below.
+        // The actual value of the end of the range should be set with
+        // AdjustExtensionRangesWithMaxEndNumber.
+        end = kMaxExtensionRangeSentinel - 1;
       } else {
         DO(ConsumeInteger(&end, "Expected integer."));
       }
@@ -1028,7 +1142,7 @@ bool Parser::ParseExtensions(DescriptorProto* message,
     range->set_end(end);
   } while (TryConsume(","));
 
-  DO(Consume(";"));
+  DO(ConsumeEndOfDeclaration(";", &extensions_location));
   return true;
 }
 
@@ -1046,7 +1160,7 @@ bool Parser::ParseExtend(RepeatedPtrField<FieldDescriptorProto>* extensions,
   io::Tokenizer::Token extendee_end = input_->previous();
 
   // Parse the block.
-  DO(Consume("{"));
+  DO(ConsumeEndOfDeclaration("{", &extend_location));
 
   bool is_first = true;
 
@@ -1083,7 +1197,7 @@ bool Parser::ParseExtend(RepeatedPtrField<FieldDescriptorProto>* extensions,
       // other statements.
       SkipStatement();
     }
-  } while(!TryConsume("}"));
+  } while (!TryConsumeEndOfDeclaration("}", NULL));
 
   return true;
 }
@@ -1109,9 +1223,9 @@ bool Parser::ParseEnumDefinition(EnumDescriptorProto* enum_type,
 
 bool Parser::ParseEnumBlock(EnumDescriptorProto* enum_type,
                             const LocationRecorder& enum_location) {
-  DO(Consume("{"));
+  DO(ConsumeEndOfDeclaration("{", &enum_location));
 
-  while (!TryConsume("}")) {
+  while (!TryConsumeEndOfDeclaration("}", NULL)) {
     if (AtEnd()) {
       AddError("Reached end of input in enum definition (missing '}').");
       return false;
@@ -1129,13 +1243,14 @@ bool Parser::ParseEnumBlock(EnumDescriptorProto* enum_type,
 
 bool Parser::ParseEnumStatement(EnumDescriptorProto* enum_type,
                                 const LocationRecorder& enum_location) {
-  if (TryConsume(";")) {
+  if (TryConsumeEndOfDeclaration(";", NULL)) {
     // empty statement; ignore
     return true;
   } else if (LookingAt("option")) {
     LocationRecorder location(enum_location,
                               EnumDescriptorProto::kOptionsFieldNumber);
-    return ParseOption(enum_type->mutable_options(), location);
+    return ParseOption(enum_type->mutable_options(), location,
+                       OPTION_STATEMENT);
   } else {
     LocationRecorder location(enum_location,
         EnumDescriptorProto::kValueFieldNumber, enum_type->value_size());
@@ -1164,16 +1279,14 @@ bool Parser::ParseEnumConstant(EnumValueDescriptorProto* enum_value,
     location.RecordLegacyLocation(
         enum_value, DescriptorPool::ErrorCollector::NUMBER);
 
-    bool is_negative = TryConsume("-");
     int number;
-    DO(ConsumeInteger(&number, "Expected integer."));
-    if (is_negative) number *= -1;
+    DO(ConsumeSignedInteger(&number, "Expected integer."));
     enum_value->set_number(number);
   }
 
   DO(ParseEnumConstantOptions(enum_value, enum_value_location));
 
-  DO(Consume(";"));
+  DO(ConsumeEndOfDeclaration(";", &enum_value_location));
 
   return true;
 }
@@ -1189,7 +1302,7 @@ bool Parser::ParseEnumConstantOptions(
   DO(Consume("["));
 
   do {
-    DO(ParseOptionAssignment(value->mutable_options(), location));
+    DO(ParseOption(value->mutable_options(), location, OPTION_ASSIGNMENT));
   } while (TryConsume(","));
 
   DO(Consume("]"));
@@ -1217,9 +1330,9 @@ bool Parser::ParseServiceDefinition(ServiceDescriptorProto* service,
 
 bool Parser::ParseServiceBlock(ServiceDescriptorProto* service,
                                const LocationRecorder& service_location) {
-  DO(Consume("{"));
+  DO(ConsumeEndOfDeclaration("{", &service_location));
 
-  while (!TryConsume("}")) {
+  while (!TryConsumeEndOfDeclaration("}", NULL)) {
     if (AtEnd()) {
       AddError("Reached end of input in service definition (missing '}').");
       return false;
@@ -1237,13 +1350,13 @@ bool Parser::ParseServiceBlock(ServiceDescriptorProto* service,
 
 bool Parser::ParseServiceStatement(ServiceDescriptorProto* service,
                                    const LocationRecorder& service_location) {
-  if (TryConsume(";")) {
+  if (TryConsumeEndOfDeclaration(";", NULL)) {
     // empty statement; ignore
     return true;
   } else if (LookingAt("option")) {
     LocationRecorder location(
         service_location, ServiceDescriptorProto::kOptionsFieldNumber);
-    return ParseOption(service->mutable_options(), location);
+    return ParseOption(service->mutable_options(), location, OPTION_STATEMENT);
   } else {
     LocationRecorder location(service_location,
         ServiceDescriptorProto::kMethodFieldNumber, service->method_size());
@@ -1286,28 +1399,41 @@ bool Parser::ParseServiceMethod(MethodDescriptorProto* method,
   }
   DO(Consume(")"));
 
-  if (TryConsume("{")) {
+  if (LookingAt("{")) {
     // Options!
-    while (!TryConsume("}")) {
-      if (AtEnd()) {
-        AddError("Reached end of input in method options (missing '}').");
-        return false;
-      }
+    DO(ParseOptions(method_location,
+                    MethodDescriptorProto::kOptionsFieldNumber,
+                    method->mutable_options()));
+  } else {
+    DO(ConsumeEndOfDeclaration(";", &method_location));
+  }
 
-      if (TryConsume(";")) {
-        // empty statement; ignore
-      } else {
-        LocationRecorder location(method_location,
-                                  MethodDescriptorProto::kOptionsFieldNumber);
-        if (!ParseOption(method->mutable_options(), location)) {
-          // This statement failed to parse.  Skip it, but keep looping to
-          // parse other statements.
-          SkipStatement();
-        }
+  return true;
+}
+
+
+bool Parser::ParseOptions(const LocationRecorder& parent_location,
+                          const int optionsFieldNumber,
+                          Message* mutable_options) {
+  // Options!
+  ConsumeEndOfDeclaration("{", &parent_location);
+  while (!TryConsumeEndOfDeclaration("}", NULL)) {
+    if (AtEnd()) {
+      AddError("Reached end of input in method options (missing '}').");
+      return false;
+    }
+
+    if (TryConsumeEndOfDeclaration(";", NULL)) {
+      // empty statement; ignore
+    } else {
+      LocationRecorder location(parent_location,
+                                optionsFieldNumber);
+      if (!ParseOption(mutable_options, location, OPTION_STATEMENT)) {
+        // This statement failed to parse.  Skip it, but keep looping to
+        // parse other statements.
+        SkipStatement();
       }
     }
-  } else {
-    DO(Consume(";"));
   }
 
   return true;
@@ -1406,32 +1532,44 @@ bool Parser::ParsePackage(FileDescriptorProto* file,
       if (!TryConsume(".")) break;
       file->mutable_package()->append(".");
     }
+
+    location.EndAt(input_->previous());
+
+    DO(ConsumeEndOfDeclaration(";", &location));
   }
 
-  DO(Consume(";"));
   return true;
 }
 
-bool Parser::ParseImport(string* import_filename,
-                         const LocationRecorder& root_location,
-                         int index) {
+bool Parser::ParseImport(RepeatedPtrField<string>* dependency,
+                         RepeatedField<int32>* public_dependency,
+                         RepeatedField<int32>* weak_dependency,
+                         const LocationRecorder& root_location) {
   DO(Consume("import"));
+  if (LookingAt("public")) {
+    LocationRecorder location(
+        root_location, FileDescriptorProto::kPublicDependencyFieldNumber,
+        public_dependency->size());
+    DO(Consume("public"));
+    *public_dependency->Add() = dependency->size();
+  } else if (LookingAt("weak")) {
+    LocationRecorder location(
+        root_location, FileDescriptorProto::kWeakDependencyFieldNumber,
+        weak_dependency->size());
+    DO(Consume("weak"));
+    *weak_dependency->Add() = dependency->size();
+  }
   {
     LocationRecorder location(root_location,
                               FileDescriptorProto::kDependencyFieldNumber,
-                              index);
-    DO(ConsumeString(import_filename,
+                              dependency->size());
+    DO(ConsumeString(dependency->Add(),
       "Expected a string naming the file to import."));
-  }
-  DO(Consume(";"));
-  return true;
-}
 
-bool Parser::ParseOption(Message* options,
-                         const LocationRecorder& options_location) {
-  DO(Consume("option"));
-  DO(ParseOptionAssignment(options, options_location));
-  DO(Consume(";"));
+    location.EndAt(input_->previous());
+
+    DO(ConsumeEndOfDeclaration(";", &location));
+  }
   return true;
 }
 
diff --git a/src/google/protobuf/compiler/parser.h b/src/google/protobuf/compiler/parser.h
index 4cc90a29..cfd3649b 100644
--- a/src/google/protobuf/compiler/parser.h
+++ b/src/google/protobuf/compiler/parser.h
@@ -116,6 +116,8 @@ class LIBPROTOBUF_EXPORT Parser {
   }
 
  private:
+  class LocationRecorder;
+
   // =================================================================
   // Error recovery helpers
 
@@ -164,6 +166,8 @@ class LIBPROTOBUF_EXPORT Parser {
   bool ConsumeIdentifier(string* output, const char* error);
   // Consume an integer and store its value in "output".
   bool ConsumeInteger(int* output, const char* error);
+  // Consume a signed integer and store its value in "output".
+  bool ConsumeSignedInteger(int* output, const char* error);
   // Consume a 64-bit integer and store its value in "output".  If the value
   // is greater than max_value, an error will be reported.
   bool ConsumeInteger64(uint64 max_value, uint64* output, const char* error);
@@ -173,6 +177,20 @@ class LIBPROTOBUF_EXPORT Parser {
   // Consume a string literal and store its (unescaped) value in "output".
   bool ConsumeString(string* output, const char* error);
 
+  // Consume a token representing the end of the statement.  Comments between
+  // this token and the next will be harvested for documentation.  The given
+  // LocationRecorder should refer to the declaration that was just parsed;
+  // it will be populated with these comments.
+  //
+  // TODO(kenton):  The LocationRecorder is const because historically locations
+  //   have been passed around by const reference, for no particularly good
+  //   reason.  We should probably go through and change them all to mutable
+  //   pointer to make this more intuitive.
+  bool TryConsumeEndOfDeclaration(const char* text,
+                                  const LocationRecorder* location);
+  bool ConsumeEndOfDeclaration(const char* text,
+                               const LocationRecorder* location);
+
   // -----------------------------------------------------------------
   // Error logging helpers
 
@@ -227,6 +245,14 @@ class LIBPROTOBUF_EXPORT Parser {
     void RecordLegacyLocation(const Message* descriptor,
         DescriptorPool::ErrorCollector::ErrorLocation location);
 
+    // Attaches leading and trailing comments to the location.  The two strings
+    // will be swapped into place, so after this is called *leading and
+    // *trailing will be empty.
+    //
+    // TODO(kenton):  See comment on TryConsumeEndOfDeclaration(), above, for
+    //   why this is const.
+    void AttachComments(string* leading, string* trailing) const;
+
    private:
     Parser* parser_;
     SourceCodeInfo::Location* location_;
@@ -265,9 +291,10 @@ class LIBPROTOBUF_EXPORT Parser {
                               const LocationRecorder& service_location);
   bool ParsePackage(FileDescriptorProto* file,
                     const LocationRecorder& root_location);
-  bool ParseImport(string* import_filename,
-                   const LocationRecorder& root_location,
-                   int index);
+  bool ParseImport(RepeatedPtrField<string>* dependency,
+                   RepeatedField<int32>* public_dependency,
+                   RepeatedField<int32>* weak_dependency,
+                   const LocationRecorder& root_location);
   bool ParseOption(Message* options,
                    const LocationRecorder& options_location);
 
@@ -329,6 +356,12 @@ class LIBPROTOBUF_EXPORT Parser {
   bool ParseServiceMethod(MethodDescriptorProto* method,
                           const LocationRecorder& method_location);
 
+
+  // Parse options of a single method or stream.
+  bool ParseOptions(const LocationRecorder& parent_location,
+                    const int optionsFieldNumber,
+                    Message* mutable_options);
+
   // Parse "required", "optional", or "repeated" and fill in "label"
   // with the value.
   bool ParseLabel(FieldDescriptorProto::Label* label);
@@ -351,11 +384,17 @@ class LIBPROTOBUF_EXPORT Parser {
   bool ParseDefaultAssignment(FieldDescriptorProto* field,
                               const LocationRecorder& field_location);
 
+  enum OptionStyle {
+    OPTION_ASSIGNMENT,  // just "name = value"
+    OPTION_STATEMENT    // "option name = value;"
+  };
+
   // Parse a single option name/value pair, e.g. "ctype = CORD".  The name
   // identifies a field of the given Message, and the value of that field
   // is set to the parsed value.
-  bool ParseOptionAssignment(Message* options,
-                             const LocationRecorder& options_location);
+  bool ParseOption(Message* options,
+                   const LocationRecorder& options_location,
+                   OptionStyle style);
 
   // Parses a single part of a multipart option name. A multipart name consists
   // of names separated by dots. Each name is either an identifier or a series
@@ -387,6 +426,10 @@ class LIBPROTOBUF_EXPORT Parser {
   bool stop_after_syntax_identifier_;
   string syntax_identifier_;
 
+  // Leading doc comments for the next declaration.  These are not complete
+  // yet; use ConsumeEndOfDeclaration() to get the complete comments.
+  string upcoming_doc_comments_;
+
   GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(Parser);
 };
 
diff --git a/src/google/protobuf/compiler/parser_unittest.cc b/src/google/protobuf/compiler/parser_unittest.cc
index 156c0dc3..c61ac60e 100644
--- a/src/google/protobuf/compiler/parser_unittest.cc
+++ b/src/google/protobuf/compiler/parser_unittest.cc
@@ -44,6 +44,7 @@
 #include <google/protobuf/wire_format.h>
 #include <google/protobuf/text_format.h>
 #include <google/protobuf/unittest.pb.h>
+#include <google/protobuf/unittest_custom_options.pb.h>
 #include <google/protobuf/stubs/strutil.h>
 #include <google/protobuf/stubs/substitute.h>
 #include <google/protobuf/stubs/map-util.h>
@@ -509,6 +510,31 @@ TEST_F(ParseMessageTest, CompoundExtensionRange) {
     "}");
 }
 
+TEST_F(ParseMessageTest, LargerMaxForMessageSetWireFormatMessages) {
+  // Messages using the message_set_wire_format option can accept larger
+  // extension numbers, as the numbers are not encoded as int32 field values
+  // rather than tags.
+  ExpectParsesTo(
+    "message TestMessage {\n"
+    "  extensions 4 to max;\n"
+    "  option message_set_wire_format = true;\n"
+    "}\n",
+
+    "message_type {"
+    "  name: \"TestMessage\""
+    "    extension_range { start:4 end: 0x7fffffff }"
+    "  options {\n"
+    "    uninterpreted_option { \n"
+    "      name {\n"
+    "        name_part: \"message_set_wire_format\"\n"
+    "        is_extension: false\n"
+    "      }\n"
+    "      identifier_value: \"true\"\n"
+    "    }\n"
+    "  }\n"
+    "}");
+}
+
 TEST_F(ParseMessageTest, Extensions) {
   ExpectParsesTo(
     "extend Extendee1 { optional int32 foo = 12; }\n"
@@ -571,6 +597,10 @@ TEST_F(ParseEnumTest, Values) {
     "  FOO = 13;\n"
     "  BAR = -10;\n"
     "  BAZ = 500;\n"
+    "  HEX_MAX = 0x7FFFFFFF;\n"
+    "  HEX_MIN = -0x80000000;\n"
+    "  INT_MAX = 2147483647;\n"
+    "  INT_MIN = -2147483648;\n"
     "}\n",
 
     "enum_type {"
@@ -578,6 +608,10 @@ TEST_F(ParseEnumTest, Values) {
     "  value { name:\"FOO\" number:13 }"
     "  value { name:\"BAR\" number:-10 }"
     "  value { name:\"BAZ\" number:500 }"
+    "  value { name:\"HEX_MAX\" number:2147483647 }"
+    "  value { name:\"HEX_MIN\" number:-2147483648 }"
+    "  value { name:\"INT_MAX\" number:2147483647 }"
+    "  value { name:\"INT_MIN\" number:-2147483648 }"
     "}");
 }
 
@@ -631,7 +665,7 @@ TEST_F(ParseServiceTest, SimpleService) {
     "}");
 }
 
-TEST_F(ParseServiceTest, Methods) {
+TEST_F(ParseServiceTest, MethodsAndStreams) {
   ExpectParsesTo(
     "service TestService {\n"
     "  rpc Foo(In1) returns (Out1);\n"
@@ -668,6 +702,20 @@ TEST_F(ParseMiscTest, ParseMultipleImports) {
     "dependency: \"baz.proto\"");
 }
 
+TEST_F(ParseMiscTest, ParsePublicImports) {
+  ExpectParsesTo(
+    "import \"foo.proto\";\n"
+    "import public \"bar.proto\";\n"
+    "import \"baz.proto\";\n"
+    "import public \"qux.proto\";\n",
+    "dependency: \"foo.proto\""
+    "dependency: \"bar.proto\""
+    "dependency: \"baz.proto\""
+    "dependency: \"qux.proto\""
+    "public_dependency: 1 "
+    "public_dependency: 3 ");
+}
+
 TEST_F(ParseMiscTest, ParsePackage) {
   ExpectParsesTo(
     "package foo.bar.baz;\n",
@@ -867,6 +915,20 @@ TEST_F(ParseErrorTest, DefaultValueTooLarge) {
     "6:36: Integer out of range.\n");
 }
 
+TEST_F(ParseErrorTest, EnumValueOutOfRange) {
+  ExpectHasErrors(
+    "enum TestEnum {\n"
+    "  HEX_TOO_BIG   =  0x80000000;\n"
+    "  HEX_TOO_SMALL = -0x80000001;\n"
+    "  INT_TOO_BIG   =  2147483648;\n"
+    "  INT_TOO_SMALL = -2147483649;\n"
+    "}\n",
+    "1:19: Integer out of range.\n"
+    "2:19: Integer out of range.\n"
+    "3:19: Integer out of range.\n"
+    "4:19: Integer out of range.\n");
+}
+
 TEST_F(ParseErrorTest, DefaultValueMissing) {
   ExpectHasErrors(
     "message TestMessage {\n"
@@ -976,6 +1038,7 @@ TEST_F(ParseErrorTest, ServiceMethodPrimitiveParams) {
     "1:26: Expected message type.\n");
 }
 
+
 TEST_F(ParseErrorTest, EofInMethodOptions) {
   ExpectHasErrors(
     "service TestService {\n"
@@ -984,6 +1047,7 @@ TEST_F(ParseErrorTest, EofInMethodOptions) {
     "1:29: Reached end of input in service definition (missing '}').\n");
 }
 
+
 TEST_F(ParseErrorTest, PrimitiveMethodInput) {
   ExpectHasErrors(
     "service TestService {\n"
@@ -992,6 +1056,7 @@ TEST_F(ParseErrorTest, PrimitiveMethodInput) {
     "1:10: Expected message type.\n");
 }
 
+
 TEST_F(ParseErrorTest, MethodOptionTypeError) {
   // This used to cause an infinite loop.
   ExpectHasErrors(
@@ -1002,6 +1067,7 @@ TEST_F(ParseErrorTest, MethodOptionTypeError) {
     "2:45: Expected \"=\".\n");
 }
 
+
 // -------------------------------------------------------------------
 // Import and package errors
 
@@ -1157,6 +1223,7 @@ TEST_F(ParserValidationErrorTest, MethodNameError) {
     "3:6: \"Bar\" is already defined in \"Foo\".\n");
 }
 
+
 TEST_F(ParserValidationErrorTest, MethodInputTypeError) {
   ExpectHasValidationErrors(
     "message Baz {}\n"
@@ -1166,6 +1233,7 @@ TEST_F(ParserValidationErrorTest, MethodInputTypeError) {
     "2:10: \"Qux\" is not defined.\n");
 }
 
+
 TEST_F(ParserValidationErrorTest, MethodOutputTypeError) {
   ExpectHasValidationErrors(
     "message Baz {}\n"
@@ -1175,6 +1243,7 @@ TEST_F(ParserValidationErrorTest, MethodOutputTypeError) {
     "2:23: \"Qux\" is not defined.\n");
 }
 
+
 // ===================================================================
 // Test that the output from FileDescriptor::DebugString() (and all other
 // descriptor types) is parseable, and results in the same Descriptor
@@ -1236,6 +1305,11 @@ TEST_F(ParseDecriptorDebugTest, TestAllDescriptorTypes) {
   // also need to give it the same name as the original.
   parsed.set_name("google/protobuf/unittest.proto");
   // We need the imported dependency before we can build our parsed proto
+  const FileDescriptor* public_import =
+      protobuf_unittest_import::PublicImportMessage::descriptor()->file();
+  FileDescriptorProto public_import_proto;
+  public_import->CopyTo(&public_import_proto);
+  ASSERT_TRUE(pool_.BuildFile(public_import_proto) != NULL);
   const FileDescriptor* import =
        protobuf_unittest_import::ImportMessage::descriptor()->file();
   FileDescriptorProto import_proto;
@@ -1258,6 +1332,45 @@ TEST_F(ParseDecriptorDebugTest, TestAllDescriptorTypes) {
   EXPECT_EQ(expected.DebugString(), parsed.DebugString());
 }
 
+TEST_F(ParseDecriptorDebugTest, TestCustomOptions) {
+  const FileDescriptor* original_file =
+     protobuf_unittest::AggregateMessage::descriptor()->file();
+  FileDescriptorProto expected;
+  original_file->CopyTo(&expected);
+
+  string debug_string = original_file->DebugString();
+
+  // Parse the debug string
+  SetupParser(debug_string.c_str());
+  FileDescriptorProto parsed;
+  parser_->Parse(input_.get(), &parsed);
+  EXPECT_EQ(io::Tokenizer::TYPE_END, input_->current().type);
+  ASSERT_EQ("", error_collector_.text_);
+
+  // We now have a FileDescriptorProto, but to compare with the expected we
+  // need to link to a FileDecriptor, then output back to a proto. We'll
+  // also need to give it the same name as the original.
+  parsed.set_name(original_file->name());
+
+  // unittest_custom_options.proto depends on descriptor.proto.
+  const FileDescriptor* import = FileDescriptorProto::descriptor()->file();
+  FileDescriptorProto import_proto;
+  import->CopyTo(&import_proto);
+  ASSERT_TRUE(pool_.BuildFile(import_proto) != NULL);
+  const FileDescriptor* actual = pool_.BuildFile(parsed);
+  ASSERT_TRUE(actual != NULL);
+  parsed.Clear();
+  actual->CopyTo(&parsed);
+
+  // The messages might be in different orders, making them hard to compare.
+  // So, sort the messages in the descriptor protos (including nested messages,
+  // recursively).
+  SortMessages(&expected);
+  SortMessages(&parsed);
+
+  EXPECT_EQ(expected.DebugString(), parsed.DebugString());
+}
+
 // ===================================================================
 // SourceCodeInfo tests.
 
@@ -1353,67 +1466,6 @@ bool FollowPath(const Message& root,
   }
 }
 
-// Split some text on line breaks.  The line breaks are retained in the output,
-// so each line (except the last) ends with a '\n', and the lines can be
-// concatenated to produce the original text.
-//
-// I couldn't find the proper string utility function for this.  Our
-// split-on-delimiter functions don't include the delimiter in the output.
-void SplitLines(const string& text, vector<string>* lines) {
-  string::size_type pos = 0;
-
-  while (pos != string::npos) {
-    string::size_type last_pos = pos;
-    pos = text.find_first_of('\n', pos);
-    if (pos != string::npos) ++pos;
-    lines->push_back(text.substr(last_pos, pos - last_pos));
-  }
-}
-
-// Look for the given tags in the given text and construct a span (as defined
-// by SourceCodeInfo.Location.span) from them.  E.g. for text like:
-//   /*a*/message /*b*/Foo/*c*/ {}/*d*/
-// There are four tags:  "a", "b", "c", and "d".  The constructed span starts
-// immediately after the start tag's trailing '/' and ends immediately before
-// the end tags leading '/'.
-void MakeExpectedSpan(const vector<string>& lines,
-                      const string& start_tag, const string& end_tag,
-                      RepeatedField<int>* output) {
-  string start_comment = "/*" + start_tag + "*/";
-  string end_comment = "/*" + end_tag + "*/";
-
-  int start_line = -1;
-  int start_column = -1;
-  for (int i = 0; i < lines.size(); i++) {
-    string::size_type pos = lines[i].find(start_comment);
-    if (pos != string::npos) {
-      start_line = i;
-      start_column = pos + start_comment.size();
-      break;
-    }
-  }
-  ASSERT_NE(start_line, -1)
-      << "Tag \"" << start_comment << "\" not found in text.";
-
-  int end_line = -1;
-  int end_column = -1;
-  for (int i = start_line; i < lines.size(); i++) {
-    string::size_type pos = lines[i].find(end_comment);
-    if (pos != string::npos) {
-      end_line = i;
-      end_column = pos;
-      break;
-    }
-  }
-  ASSERT_NE(end_line, -1)
-      << "Tag \"" << end_comment << "\" not found in text.";
-
-  output->Add(start_line);
-  output->Add(start_column);
-  if (end_line != start_line) output->Add(end_line);
-  output->Add(end_column);
-}
-
 // Check if two spans are equal.
 bool CompareSpans(const RepeatedField<int>& span1,
                   const RepeatedField<int>& span2) {
@@ -1434,8 +1486,8 @@ class SourceInfoTest : public ParserTest {
   // Parse the given text as a .proto file and populate the spans_ map with
   // all the source location spans in its SourceCodeInfo table.
   bool Parse(const char* text) {
-    SetupParser(text);
-    SplitLines(text, &lines_);
+    ExtractMarkers(text);
+    SetupParser(text_without_markers_.c_str());
     if (!parser_->Parse(input_.get(), &file_)) {
       return false;
     }
@@ -1470,19 +1522,38 @@ class SourceInfoTest : public ParserTest {
   // part of the FileDescriptorProto.  (If unclear, look at the actual tests;
   // it should quickly become obvious.)
 
-  bool HasSpan(const char* start_tag, const char* end_tag,
+  bool HasSpan(char start_marker, char end_marker,
                const Message& descriptor_proto) {
-    return HasSpan(start_tag, end_tag, descriptor_proto, NULL, -1);
+    return HasSpanWithComment(
+        start_marker, end_marker, descriptor_proto, NULL, -1, NULL, NULL);
   }
 
-  bool HasSpan(const char* start_tag, const char* end_tag,
+  bool HasSpanWithComment(char start_marker, char end_marker,
+                          const Message& descriptor_proto,
+                          const char* expected_leading_comments,
+                          const char* expected_trailing_comments) {
+    return HasSpanWithComment(
+        start_marker, end_marker, descriptor_proto, NULL, -1,
+        expected_leading_comments, expected_trailing_comments);
+  }
+
+  bool HasSpan(char start_marker, char end_marker,
                const Message& descriptor_proto, const string& field_name) {
-    return HasSpan(start_tag, end_tag, descriptor_proto, field_name, -1);
+    return HasSpan(start_marker, end_marker, descriptor_proto, field_name, -1);
   }
 
-  bool HasSpan(const char* start_tag, const char* end_tag,
+  bool HasSpan(char start_marker, char end_marker,
                const Message& descriptor_proto, const string& field_name,
                int index) {
+    return HasSpan(start_marker, end_marker, descriptor_proto,
+                   field_name, index, NULL, NULL);
+  }
+
+  bool HasSpan(char start_marker, char end_marker,
+               const Message& descriptor_proto,
+               const string& field_name, int index,
+               const char* expected_leading_comments,
+               const char* expected_trailing_comments) {
     const FieldDescriptor* field =
         descriptor_proto.GetDescriptor()->FindFieldByName(field_name);
     if (field == NULL) {
@@ -1491,29 +1562,34 @@ class SourceInfoTest : public ParserTest {
       return false;
     }
 
-    return HasSpan(start_tag, end_tag, descriptor_proto, field, index);
+    return HasSpanWithComment(
+        start_marker, end_marker, descriptor_proto, field, index,
+        expected_leading_comments, expected_trailing_comments);
   }
 
   bool HasSpan(const Message& descriptor_proto) {
-    return HasSpan(NULL, NULL, descriptor_proto, NULL, -1);
+    return HasSpanWithComment(
+        '\0', '\0', descriptor_proto, NULL, -1, NULL, NULL);
   }
 
   bool HasSpan(const Message& descriptor_proto, const string& field_name) {
-    return HasSpan(NULL, NULL, descriptor_proto, field_name, -1);
+    return HasSpan('\0', '\0', descriptor_proto, field_name, -1);
   }
 
   bool HasSpan(const Message& descriptor_proto, const string& field_name,
                int index) {
-    return HasSpan(NULL, NULL, descriptor_proto, field_name, index);
+    return HasSpan('\0', '\0', descriptor_proto, field_name, index);
   }
 
-  bool HasSpan(const char* start_tag, const char* end_tag,
-               const Message& descriptor_proto, const FieldDescriptor* field,
-               int index) {
+  bool HasSpanWithComment(char start_marker, char end_marker,
+                          const Message& descriptor_proto,
+                          const FieldDescriptor* field, int index,
+                          const char* expected_leading_comments,
+                          const char* expected_trailing_comments) {
     pair<SpanMap::iterator, SpanMap::iterator> range =
         spans_.equal_range(SpanKey(descriptor_proto, field, index));
 
-    if (start_tag == NULL) {
+    if (start_marker == '\0') {
       if (range.first == range.second) {
         return false;
       } else {
@@ -1521,11 +1597,34 @@ class SourceInfoTest : public ParserTest {
         return true;
       }
     } else {
+      pair<int, int> start_pos = FindOrDie(markers_, start_marker);
+      pair<int, int> end_pos = FindOrDie(markers_, end_marker);
+
       RepeatedField<int> expected_span;
-      MakeExpectedSpan(lines_, start_tag, end_tag, &expected_span);
+      expected_span.Add(start_pos.first);
+      expected_span.Add(start_pos.second);
+      if (end_pos.first != start_pos.first) {
+        expected_span.Add(end_pos.first);
+      }
+      expected_span.Add(end_pos.second);
 
       for (SpanMap::iterator iter = range.first; iter != range.second; ++iter) {
         if (CompareSpans(expected_span, iter->second->span())) {
+          if (expected_leading_comments == NULL) {
+            EXPECT_FALSE(iter->second->has_leading_comments());
+          } else {
+            EXPECT_TRUE(iter->second->has_leading_comments());
+            EXPECT_EQ(expected_leading_comments,
+                      iter->second->leading_comments());
+          }
+          if (expected_trailing_comments == NULL) {
+            EXPECT_FALSE(iter->second->has_trailing_comments());
+          } else {
+            EXPECT_TRUE(iter->second->has_trailing_comments());
+            EXPECT_EQ(expected_trailing_comments,
+                      iter->second->trailing_comments());
+          }
+
           spans_.erase(iter);
           return true;
         }
@@ -1542,10 +1641,11 @@ class SourceInfoTest : public ParserTest {
     int index;
 
     inline SpanKey() {}
-    inline SpanKey(const Message& descriptor_proto,
-                   const FieldDescriptor* field,
-                   int index)
-        : descriptor_proto(&descriptor_proto), field(field), index(index) {}
+    inline SpanKey(const Message& descriptor_proto_param,
+                   const FieldDescriptor* field_param,
+                   int index_param)
+        : descriptor_proto(&descriptor_proto_param), field(field_param),
+          index(index_param) {}
 
     inline bool operator<(const SpanKey& other) const {
       if (descriptor_proto < other.descriptor_proto) return true;
@@ -1558,32 +1658,63 @@ class SourceInfoTest : public ParserTest {
 
   typedef multimap<SpanKey, const SourceCodeInfo::Location*> SpanMap;
   SpanMap spans_;
-  vector<string> lines_;
+  map<char, pair<int, int> > markers_;
+  string text_without_markers_;
+
+  void ExtractMarkers(const char* text) {
+    markers_.clear();
+    text_without_markers_.clear();
+    int line = 0;
+    int column = 0;
+    while (*text != '\0') {
+      if (*text == '$') {
+        ++text;
+        GOOGLE_CHECK_NE('\0', *text);
+        if (*text == '$') {
+          text_without_markers_ += '$';
+          ++column;
+        } else {
+          markers_[*text] = make_pair(line, column);
+          ++text;
+          GOOGLE_CHECK_EQ('$', *text);
+        }
+      } else if (*text == '\n') {
+        ++line;
+        column = 0;
+        text_without_markers_ += *text;
+      } else {
+        text_without_markers_ += *text;
+        ++column;
+      }
+      ++text;
+    }
+  }
 };
 
 TEST_F(SourceInfoTest, BasicFileDecls) {
   EXPECT_TRUE(Parse(
-      "/*a*/syntax = \"proto2\";\n"
-      "package /*b*/foo.bar/*c*/;\n"
-      "import /*d*/\"baz.proto\"/*e*/;\n"
-      "import /*f*/\"qux.proto\"/*g*/;/*h*/\n"
+      "$a$syntax = \"proto2\";\n"
+      "package $b$foo.bar$c$;\n"
+      "import $d$\"baz.proto\"$e$;\n"
+      "import $f$\"qux.proto\"$g$;$h$\n"
+      "\n"
       "// comment ignored\n"));
 
-  EXPECT_TRUE(HasSpan("a", "h", file_));
-  EXPECT_TRUE(HasSpan("b", "c", file_, "package"));
-  EXPECT_TRUE(HasSpan("d", "e", file_, "dependency", 0));
-  EXPECT_TRUE(HasSpan("f", "g", file_, "dependency", 1));
+  EXPECT_TRUE(HasSpan('a', 'h', file_));
+  EXPECT_TRUE(HasSpan('b', 'c', file_, "package"));
+  EXPECT_TRUE(HasSpan('d', 'e', file_, "dependency", 0));
+  EXPECT_TRUE(HasSpan('f', 'g', file_, "dependency", 1));
 }
 
 TEST_F(SourceInfoTest, Messages) {
   EXPECT_TRUE(Parse(
-      "/*a*/message /*b*/Foo/*c*/ {}/*d*/\n"
-      "/*e*/message /*f*/Bar/*g*/ {}/*h*/\n"));
+      "$a$message $b$Foo$c$ {}$d$\n"
+      "$e$message $f$Bar$g$ {}$h$\n"));
 
-  EXPECT_TRUE(HasSpan("a", "d", file_.message_type(0)));
-  EXPECT_TRUE(HasSpan("b", "c", file_.message_type(0), "name"));
-  EXPECT_TRUE(HasSpan("e", "h", file_.message_type(1)));
-  EXPECT_TRUE(HasSpan("f", "g", file_.message_type(1), "name"));
+  EXPECT_TRUE(HasSpan('a', 'd', file_.message_type(0)));
+  EXPECT_TRUE(HasSpan('b', 'c', file_.message_type(0), "name"));
+  EXPECT_TRUE(HasSpan('e', 'h', file_.message_type(1)));
+  EXPECT_TRUE(HasSpan('f', 'g', file_.message_type(1), "name"));
 
   // Ignore these.
   EXPECT_TRUE(HasSpan(file_));
@@ -1592,24 +1723,24 @@ TEST_F(SourceInfoTest, Messages) {
 TEST_F(SourceInfoTest, Fields) {
   EXPECT_TRUE(Parse(
       "message Foo {\n"
-      "  /*a*/optional/*b*/ /*c*/int32/*d*/ /*e*/bar/*f*/ = /*g*/1/*h*/;/*i*/\n"
-      "  /*j*/repeated/*k*/ /*l*/X.Y/*m*/ /*n*/baz/*o*/ = /*p*/2/*q*/;/*r*/\n"
+      "  $a$optional$b$ $c$int32$d$ $e$bar$f$ = $g$1$h$;$i$\n"
+      "  $j$repeated$k$ $l$X.Y$m$ $n$baz$o$ = $p$2$q$;$r$\n"
       "}\n"));
 
   const FieldDescriptorProto& field1 = file_.message_type(0).field(0);
   const FieldDescriptorProto& field2 = file_.message_type(0).field(1);
 
-  EXPECT_TRUE(HasSpan("a", "i", field1));
-  EXPECT_TRUE(HasSpan("a", "b", field1, "label"));
-  EXPECT_TRUE(HasSpan("c", "d", field1, "type"));
-  EXPECT_TRUE(HasSpan("e", "f", field1, "name"));
-  EXPECT_TRUE(HasSpan("g", "h", field1, "number"));
+  EXPECT_TRUE(HasSpan('a', 'i', field1));
+  EXPECT_TRUE(HasSpan('a', 'b', field1, "label"));
+  EXPECT_TRUE(HasSpan('c', 'd', field1, "type"));
+  EXPECT_TRUE(HasSpan('e', 'f', field1, "name"));
+  EXPECT_TRUE(HasSpan('g', 'h', field1, "number"));
 
-  EXPECT_TRUE(HasSpan("j", "r", field2));
-  EXPECT_TRUE(HasSpan("j", "k", field2, "label"));
-  EXPECT_TRUE(HasSpan("l", "m", field2, "type_name"));
-  EXPECT_TRUE(HasSpan("n", "o", field2, "name"));
-  EXPECT_TRUE(HasSpan("p", "q", field2, "number"));
+  EXPECT_TRUE(HasSpan('j', 'r', field2));
+  EXPECT_TRUE(HasSpan('j', 'k', field2, "label"));
+  EXPECT_TRUE(HasSpan('l', 'm', field2, "type_name"));
+  EXPECT_TRUE(HasSpan('n', 'o', field2, "name"));
+  EXPECT_TRUE(HasSpan('p', 'q', field2, "number"));
 
   // Ignore these.
   EXPECT_TRUE(HasSpan(file_));
@@ -1619,31 +1750,31 @@ TEST_F(SourceInfoTest, Fields) {
 
 TEST_F(SourceInfoTest, Extensions) {
   EXPECT_TRUE(Parse(
-      "/*a*/extend /*b*/Foo/*c*/ {\n"
-      "  /*d*/optional/*e*/ int32 bar = 1;/*f*/\n"
-      "  /*g*/repeated/*h*/ X.Y baz = 2;/*i*/\n"
-      "}/*j*/\n"
-      "/*k*/extend /*l*/Bar/*m*/ {\n"
-      "  /*n*/optional int32 qux = 1;/*o*/\n"
-      "}/*p*/\n"));
+      "$a$extend $b$Foo$c$ {\n"
+      "  $d$optional$e$ int32 bar = 1;$f$\n"
+      "  $g$repeated$h$ X.Y baz = 2;$i$\n"
+      "}$j$\n"
+      "$k$extend $l$Bar$m$ {\n"
+      "  $n$optional int32 qux = 1;$o$\n"
+      "}$p$\n"));
 
   const FieldDescriptorProto& field1 = file_.extension(0);
   const FieldDescriptorProto& field2 = file_.extension(1);
   const FieldDescriptorProto& field3 = file_.extension(2);
 
-  EXPECT_TRUE(HasSpan("a", "j", file_, "extension"));
-  EXPECT_TRUE(HasSpan("k", "p", file_, "extension"));
+  EXPECT_TRUE(HasSpan('a', 'j', file_, "extension"));
+  EXPECT_TRUE(HasSpan('k', 'p', file_, "extension"));
 
-  EXPECT_TRUE(HasSpan("d", "f", field1));
-  EXPECT_TRUE(HasSpan("d", "e", field1, "label"));
-  EXPECT_TRUE(HasSpan("b", "c", field1, "extendee"));
+  EXPECT_TRUE(HasSpan('d', 'f', field1));
+  EXPECT_TRUE(HasSpan('d', 'e', field1, "label"));
+  EXPECT_TRUE(HasSpan('b', 'c', field1, "extendee"));
 
-  EXPECT_TRUE(HasSpan("g", "i", field2));
-  EXPECT_TRUE(HasSpan("g", "h", field2, "label"));
-  EXPECT_TRUE(HasSpan("b", "c", field2, "extendee"));
+  EXPECT_TRUE(HasSpan('g', 'i', field2));
+  EXPECT_TRUE(HasSpan('g', 'h', field2, "label"));
+  EXPECT_TRUE(HasSpan('b', 'c', field2, "extendee"));
 
-  EXPECT_TRUE(HasSpan("n", "o", field3));
-  EXPECT_TRUE(HasSpan("l", "m", field3, "extendee"));
+  EXPECT_TRUE(HasSpan('n', 'o', field3));
+  EXPECT_TRUE(HasSpan('l', 'm', field3, "extendee"));
 
   // Ignore these.
   EXPECT_TRUE(HasSpan(file_));
@@ -1662,32 +1793,32 @@ TEST_F(SourceInfoTest, Extensions) {
 TEST_F(SourceInfoTest, NestedExtensions) {
   EXPECT_TRUE(Parse(
       "message Message {\n"
-      "  /*a*/extend /*b*/Foo/*c*/ {\n"
-      "    /*d*/optional/*e*/ int32 bar = 1;/*f*/\n"
-      "    /*g*/repeated/*h*/ X.Y baz = 2;/*i*/\n"
-      "  }/*j*/\n"
-      "  /*k*/extend /*l*/Bar/*m*/ {\n"
-      "    /*n*/optional int32 qux = 1;/*o*/\n"
-      "  }/*p*/\n"
+      "  $a$extend $b$Foo$c$ {\n"
+      "    $d$optional$e$ int32 bar = 1;$f$\n"
+      "    $g$repeated$h$ X.Y baz = 2;$i$\n"
+      "  }$j$\n"
+      "  $k$extend $l$Bar$m$ {\n"
+      "    $n$optional int32 qux = 1;$o$\n"
+      "  }$p$\n"
       "}\n"));
 
   const FieldDescriptorProto& field1 = file_.message_type(0).extension(0);
   const FieldDescriptorProto& field2 = file_.message_type(0).extension(1);
   const FieldDescriptorProto& field3 = file_.message_type(0).extension(2);
 
-  EXPECT_TRUE(HasSpan("a", "j", file_.message_type(0), "extension"));
-  EXPECT_TRUE(HasSpan("k", "p", file_.message_type(0), "extension"));
+  EXPECT_TRUE(HasSpan('a', 'j', file_.message_type(0), "extension"));
+  EXPECT_TRUE(HasSpan('k', 'p', file_.message_type(0), "extension"));
 
-  EXPECT_TRUE(HasSpan("d", "f", field1));
-  EXPECT_TRUE(HasSpan("d", "e", field1, "label"));
-  EXPECT_TRUE(HasSpan("b", "c", field1, "extendee"));
+  EXPECT_TRUE(HasSpan('d', 'f', field1));
+  EXPECT_TRUE(HasSpan('d', 'e', field1, "label"));
+  EXPECT_TRUE(HasSpan('b', 'c', field1, "extendee"));
 
-  EXPECT_TRUE(HasSpan("g", "i", field2));
-  EXPECT_TRUE(HasSpan("g", "h", field2, "label"));
-  EXPECT_TRUE(HasSpan("b", "c", field2, "extendee"));
+  EXPECT_TRUE(HasSpan('g', 'i', field2));
+  EXPECT_TRUE(HasSpan('g', 'h', field2, "label"));
+  EXPECT_TRUE(HasSpan('b', 'c', field2, "extendee"));
 
-  EXPECT_TRUE(HasSpan("n", "o", field3));
-  EXPECT_TRUE(HasSpan("l", "m", field3, "extendee"));
+  EXPECT_TRUE(HasSpan('n', 'o', field3));
+  EXPECT_TRUE(HasSpan('l', 'm', field3, "extendee"));
 
   // Ignore these.
   EXPECT_TRUE(HasSpan(file_));
@@ -1708,8 +1839,8 @@ TEST_F(SourceInfoTest, NestedExtensions) {
 TEST_F(SourceInfoTest, ExtensionRanges) {
   EXPECT_TRUE(Parse(
       "message Message {\n"
-      "  /*a*/extensions /*b*/1/*c*/ to /*d*/4/*e*/, /*f*/6/*g*/;/*h*/\n"
-      "  /*i*/extensions /*j*/8/*k*/ to /*l*/max/*m*/;/*n*/\n"
+      "  $a$extensions $b$1$c$ to $d$4$e$, $f$6$g$;$h$\n"
+      "  $i$extensions $j$8$k$ to $l$max$m$;$n$\n"
       "}\n"));
 
   const DescriptorProto::ExtensionRange& range1 =
@@ -1719,20 +1850,20 @@ TEST_F(SourceInfoTest, ExtensionRanges) {
   const DescriptorProto::ExtensionRange& range3 =
       file_.message_type(0).extension_range(2);
 
-  EXPECT_TRUE(HasSpan("a", "h", file_.message_type(0), "extension_range"));
-  EXPECT_TRUE(HasSpan("i", "n", file_.message_type(0), "extension_range"));
+  EXPECT_TRUE(HasSpan('a', 'h', file_.message_type(0), "extension_range"));
+  EXPECT_TRUE(HasSpan('i', 'n', file_.message_type(0), "extension_range"));
 
-  EXPECT_TRUE(HasSpan("b", "e", range1));
-  EXPECT_TRUE(HasSpan("b", "c", range1, "start"));
-  EXPECT_TRUE(HasSpan("d", "e", range1, "end"));
+  EXPECT_TRUE(HasSpan('b', 'e', range1));
+  EXPECT_TRUE(HasSpan('b', 'c', range1, "start"));
+  EXPECT_TRUE(HasSpan('d', 'e', range1, "end"));
 
-  EXPECT_TRUE(HasSpan("f", "g", range2));
-  EXPECT_TRUE(HasSpan("f", "g", range2, "start"));
-  EXPECT_TRUE(HasSpan("f", "g", range2, "end"));
+  EXPECT_TRUE(HasSpan('f', 'g', range2));
+  EXPECT_TRUE(HasSpan('f', 'g', range2, "start"));
+  EXPECT_TRUE(HasSpan('f', 'g', range2, "end"));
 
-  EXPECT_TRUE(HasSpan("j", "m", range3));
-  EXPECT_TRUE(HasSpan("j", "k", range3, "start"));
-  EXPECT_TRUE(HasSpan("l", "m", range3, "end"));
+  EXPECT_TRUE(HasSpan('j', 'm', range3));
+  EXPECT_TRUE(HasSpan('j', 'k', range3, "start"));
+  EXPECT_TRUE(HasSpan('l', 'm', range3, "end"));
 
   // Ignore these.
   EXPECT_TRUE(HasSpan(file_));
@@ -1743,22 +1874,22 @@ TEST_F(SourceInfoTest, ExtensionRanges) {
 TEST_F(SourceInfoTest, NestedMessages) {
   EXPECT_TRUE(Parse(
       "message Foo {\n"
-      "  /*a*/message /*b*/Bar/*c*/ {\n"
-      "    /*d*/message /*e*/Baz/*f*/ {}/*g*/\n"
-      "  }/*h*/\n"
-      "  /*i*/message /*j*/Qux/*k*/ {}/*l*/\n"
+      "  $a$message $b$Bar$c$ {\n"
+      "    $d$message $e$Baz$f$ {}$g$\n"
+      "  }$h$\n"
+      "  $i$message $j$Qux$k$ {}$l$\n"
       "}\n"));
 
   const DescriptorProto& bar = file_.message_type(0).nested_type(0);
   const DescriptorProto& baz = bar.nested_type(0);
   const DescriptorProto& qux = file_.message_type(0).nested_type(1);
 
-  EXPECT_TRUE(HasSpan("a", "h", bar));
-  EXPECT_TRUE(HasSpan("b", "c", bar, "name"));
-  EXPECT_TRUE(HasSpan("d", "g", baz));
-  EXPECT_TRUE(HasSpan("e", "f", baz, "name"));
-  EXPECT_TRUE(HasSpan("i", "l", qux));
-  EXPECT_TRUE(HasSpan("j", "k", qux, "name"));
+  EXPECT_TRUE(HasSpan('a', 'h', bar));
+  EXPECT_TRUE(HasSpan('b', 'c', bar, "name"));
+  EXPECT_TRUE(HasSpan('d', 'g', baz));
+  EXPECT_TRUE(HasSpan('e', 'f', baz, "name"));
+  EXPECT_TRUE(HasSpan('i', 'l', qux));
+  EXPECT_TRUE(HasSpan('j', 'k', qux, "name"));
 
   // Ignore these.
   EXPECT_TRUE(HasSpan(file_));
@@ -1770,9 +1901,9 @@ TEST_F(SourceInfoTest, Groups) {
   EXPECT_TRUE(Parse(
       "message Foo {\n"
       "  message Bar {}\n"
-      "  /*a*/optional/*b*/ /*c*/group/*d*/ /*e*/Baz/*f*/ = /*g*/1/*h*/ {\n"
-      "    /*i*/message Qux {}/*j*/\n"
-      "  }/*k*/\n"
+      "  $a$optional$b$ $c$group$d$ $e$Baz$f$ = $g$1$h$ {\n"
+      "    $i$message Qux {}$j$\n"
+      "  }$k$\n"
       "}\n"));
 
   const DescriptorProto& bar = file_.message_type(0).nested_type(0);
@@ -1780,16 +1911,16 @@ TEST_F(SourceInfoTest, Groups) {
   const DescriptorProto& qux = baz.nested_type(0);
   const FieldDescriptorProto& field = file_.message_type(0).field(0);
 
-  EXPECT_TRUE(HasSpan("a", "k", field));
-  EXPECT_TRUE(HasSpan("a", "b", field, "label"));
-  EXPECT_TRUE(HasSpan("c", "d", field, "type"));
-  EXPECT_TRUE(HasSpan("e", "f", field, "name"));
-  EXPECT_TRUE(HasSpan("e", "f", field, "type_name"));
-  EXPECT_TRUE(HasSpan("g", "h", field, "number"));
+  EXPECT_TRUE(HasSpan('a', 'k', field));
+  EXPECT_TRUE(HasSpan('a', 'b', field, "label"));
+  EXPECT_TRUE(HasSpan('c', 'd', field, "type"));
+  EXPECT_TRUE(HasSpan('e', 'f', field, "name"));
+  EXPECT_TRUE(HasSpan('e', 'f', field, "type_name"));
+  EXPECT_TRUE(HasSpan('g', 'h', field, "number"));
 
-  EXPECT_TRUE(HasSpan("a", "k", baz));
-  EXPECT_TRUE(HasSpan("e", "f", baz, "name"));
-  EXPECT_TRUE(HasSpan("i", "j", qux));
+  EXPECT_TRUE(HasSpan('a', 'k', baz));
+  EXPECT_TRUE(HasSpan('e', 'f', baz, "name"));
+  EXPECT_TRUE(HasSpan('i', 'j', qux));
 
   // Ignore these.
   EXPECT_TRUE(HasSpan(file_));
@@ -1802,13 +1933,13 @@ TEST_F(SourceInfoTest, Groups) {
 
 TEST_F(SourceInfoTest, Enums) {
   EXPECT_TRUE(Parse(
-      "/*a*/enum /*b*/Foo/*c*/ {}/*d*/\n"
-      "/*e*/enum /*f*/Bar/*g*/ {}/*h*/\n"));
+      "$a$enum $b$Foo$c$ {}$d$\n"
+      "$e$enum $f$Bar$g$ {}$h$\n"));
 
-  EXPECT_TRUE(HasSpan("a", "d", file_.enum_type(0)));
-  EXPECT_TRUE(HasSpan("b", "c", file_.enum_type(0), "name"));
-  EXPECT_TRUE(HasSpan("e", "h", file_.enum_type(1)));
-  EXPECT_TRUE(HasSpan("f", "g", file_.enum_type(1), "name"));
+  EXPECT_TRUE(HasSpan('a', 'd', file_.enum_type(0)));
+  EXPECT_TRUE(HasSpan('b', 'c', file_.enum_type(0), "name"));
+  EXPECT_TRUE(HasSpan('e', 'h', file_.enum_type(1)));
+  EXPECT_TRUE(HasSpan('f', 'g', file_.enum_type(1), "name"));
 
   // Ignore these.
   EXPECT_TRUE(HasSpan(file_));
@@ -1817,19 +1948,19 @@ TEST_F(SourceInfoTest, Enums) {
 TEST_F(SourceInfoTest, EnumValues) {
   EXPECT_TRUE(Parse(
       "enum Foo {\n"
-      "  /*a*/BAR/*b*/ = /*c*/1/*d*/;/*e*/\n"
-      "  /*f*/BAZ/*g*/ = /*h*/2/*i*/;/*j*/\n"
+      "  $a$BAR$b$ = $c$1$d$;$e$\n"
+      "  $f$BAZ$g$ = $h$2$i$;$j$\n"
       "}"));
 
   const EnumValueDescriptorProto& bar = file_.enum_type(0).value(0);
   const EnumValueDescriptorProto& baz = file_.enum_type(0).value(1);
 
-  EXPECT_TRUE(HasSpan("a", "e", bar));
-  EXPECT_TRUE(HasSpan("a", "b", bar, "name"));
-  EXPECT_TRUE(HasSpan("c", "d", bar, "number"));
-  EXPECT_TRUE(HasSpan("f", "j", baz));
-  EXPECT_TRUE(HasSpan("f", "g", baz, "name"));
-  EXPECT_TRUE(HasSpan("h", "i", baz, "number"));
+  EXPECT_TRUE(HasSpan('a', 'e', bar));
+  EXPECT_TRUE(HasSpan('a', 'b', bar, "name"));
+  EXPECT_TRUE(HasSpan('c', 'd', bar, "number"));
+  EXPECT_TRUE(HasSpan('f', 'j', baz));
+  EXPECT_TRUE(HasSpan('f', 'g', baz, "name"));
+  EXPECT_TRUE(HasSpan('h', 'i', baz, "number"));
 
   // Ignore these.
   EXPECT_TRUE(HasSpan(file_));
@@ -1840,17 +1971,17 @@ TEST_F(SourceInfoTest, EnumValues) {
 TEST_F(SourceInfoTest, NestedEnums) {
   EXPECT_TRUE(Parse(
       "message Foo {\n"
-      "  /*a*/enum /*b*/Bar/*c*/ {}/*d*/\n"
-      "  /*e*/enum /*f*/Baz/*g*/ {}/*h*/\n"
+      "  $a$enum $b$Bar$c$ {}$d$\n"
+      "  $e$enum $f$Baz$g$ {}$h$\n"
       "}\n"));
 
   const EnumDescriptorProto& bar = file_.message_type(0).enum_type(0);
   const EnumDescriptorProto& baz = file_.message_type(0).enum_type(1);
 
-  EXPECT_TRUE(HasSpan("a", "d", bar));
-  EXPECT_TRUE(HasSpan("b", "c", bar, "name"));
-  EXPECT_TRUE(HasSpan("e", "h", baz));
-  EXPECT_TRUE(HasSpan("f", "g", baz, "name"));
+  EXPECT_TRUE(HasSpan('a', 'd', bar));
+  EXPECT_TRUE(HasSpan('b', 'c', bar, "name"));
+  EXPECT_TRUE(HasSpan('e', 'h', baz));
+  EXPECT_TRUE(HasSpan('f', 'g', baz, "name"));
 
   // Ignore these.
   EXPECT_TRUE(HasSpan(file_));
@@ -1860,37 +1991,37 @@ TEST_F(SourceInfoTest, NestedEnums) {
 
 TEST_F(SourceInfoTest, Services) {
   EXPECT_TRUE(Parse(
-      "/*a*/service /*b*/Foo/*c*/ {}/*d*/\n"
-      "/*e*/service /*f*/Bar/*g*/ {}/*h*/\n"));
+      "$a$service $b$Foo$c$ {}$d$\n"
+      "$e$service $f$Bar$g$ {}$h$\n"));
 
-  EXPECT_TRUE(HasSpan("a", "d", file_.service(0)));
-  EXPECT_TRUE(HasSpan("b", "c", file_.service(0), "name"));
-  EXPECT_TRUE(HasSpan("e", "h", file_.service(1)));
-  EXPECT_TRUE(HasSpan("f", "g", file_.service(1), "name"));
+  EXPECT_TRUE(HasSpan('a', 'd', file_.service(0)));
+  EXPECT_TRUE(HasSpan('b', 'c', file_.service(0), "name"));
+  EXPECT_TRUE(HasSpan('e', 'h', file_.service(1)));
+  EXPECT_TRUE(HasSpan('f', 'g', file_.service(1), "name"));
 
   // Ignore these.
   EXPECT_TRUE(HasSpan(file_));
 }
 
-TEST_F(SourceInfoTest, Methods) {
+TEST_F(SourceInfoTest, MethodsAndStreams) {
   EXPECT_TRUE(Parse(
       "service Foo {\n"
-      "  /*a*/rpc /*b*/Bar/*c*/(/*d*/X/*e*/) returns(/*f*/Y/*g*/);/*h*/"
-      "  /*i*/rpc /*j*/Baz/*k*/(/*l*/Z/*m*/) returns(/*n*/W/*o*/);/*p*/"
+      "  $a$rpc $b$Bar$c$($d$X$e$) returns($f$Y$g$);$h$"
+      "  $i$rpc $j$Baz$k$($l$Z$m$) returns($n$W$o$);$p$"
       "}"));
 
   const MethodDescriptorProto& bar = file_.service(0).method(0);
   const MethodDescriptorProto& baz = file_.service(0).method(1);
 
-  EXPECT_TRUE(HasSpan("a", "h", bar));
-  EXPECT_TRUE(HasSpan("b", "c", bar, "name"));
-  EXPECT_TRUE(HasSpan("d", "e", bar, "input_type"));
-  EXPECT_TRUE(HasSpan("f", "g", bar, "output_type"));
+  EXPECT_TRUE(HasSpan('a', 'h', bar));
+  EXPECT_TRUE(HasSpan('b', 'c', bar, "name"));
+  EXPECT_TRUE(HasSpan('d', 'e', bar, "input_type"));
+  EXPECT_TRUE(HasSpan('f', 'g', bar, "output_type"));
 
-  EXPECT_TRUE(HasSpan("i", "p", baz));
-  EXPECT_TRUE(HasSpan("j", "k", baz, "name"));
-  EXPECT_TRUE(HasSpan("l", "m", baz, "input_type"));
-  EXPECT_TRUE(HasSpan("n", "o", baz, "output_type"));
+  EXPECT_TRUE(HasSpan('i', 'p', baz));
+  EXPECT_TRUE(HasSpan('j', 'k', baz, "name"));
+  EXPECT_TRUE(HasSpan('l', 'm', baz, "input_type"));
+  EXPECT_TRUE(HasSpan('n', 'o', baz, "output_type"));
 
   // Ignore these.
   EXPECT_TRUE(HasSpan(file_));
@@ -1900,13 +2031,13 @@ TEST_F(SourceInfoTest, Methods) {
 
 TEST_F(SourceInfoTest, Options) {
   EXPECT_TRUE(Parse(
-      "/*a*/option /*b*/foo/*c*/./*d*/(/*e*/bar.baz/*f*/)/*g*/ = "
-          "/*h*/123/*i*/;/*j*/\n"
-      "/*k*/option qux = /*l*/-123/*m*/;/*n*/\n"
-      "/*o*/option corge = /*p*/abc/*q*/;/*r*/\n"
-      "/*s*/option grault = /*t*/'blah'/*u*/;/*v*/\n"
-      "/*w*/option garply = /*x*/{ yadda yadda }/*y*/;/*z*/\n"
-      "/*0*/option waldo = /*1*/123.0/*2*/;/*3*/\n"
+      "$a$option $b$foo$c$.$d$($e$bar.baz$f$)$g$ = "
+          "$h$123$i$;$j$\n"
+      "$k$option qux = $l$-123$m$;$n$\n"
+      "$o$option corge = $p$abc$q$;$r$\n"
+      "$s$option grault = $t$'blah'$u$;$v$\n"
+      "$w$option garply = $x${ yadda yadda }$y$;$z$\n"
+      "$0$option waldo = $1$123.0$2$;$3$\n"
   ));
 
   const UninterpretedOption& option1 = file_.options().uninterpreted_option(0);
@@ -1916,29 +2047,29 @@ TEST_F(SourceInfoTest, Options) {
   const UninterpretedOption& option5 = file_.options().uninterpreted_option(4);
   const UninterpretedOption& option6 = file_.options().uninterpreted_option(5);
 
-  EXPECT_TRUE(HasSpan("a", "j", file_.options()));
-  EXPECT_TRUE(HasSpan("b", "i", option1));
-  EXPECT_TRUE(HasSpan("b", "g", option1, "name"));
-  EXPECT_TRUE(HasSpan("b", "c", option1.name(0)));
-  EXPECT_TRUE(HasSpan("b", "c", option1.name(0), "name_part"));
-  EXPECT_TRUE(HasSpan("d", "g", option1.name(1)));
-  EXPECT_TRUE(HasSpan("e", "f", option1.name(1), "name_part"));
-  EXPECT_TRUE(HasSpan("h", "i", option1, "positive_int_value"));
+  EXPECT_TRUE(HasSpan('a', 'j', file_.options()));
+  EXPECT_TRUE(HasSpan('a', 'j', option1));
+  EXPECT_TRUE(HasSpan('b', 'g', option1, "name"));
+  EXPECT_TRUE(HasSpan('b', 'c', option1.name(0)));
+  EXPECT_TRUE(HasSpan('b', 'c', option1.name(0), "name_part"));
+  EXPECT_TRUE(HasSpan('d', 'g', option1.name(1)));
+  EXPECT_TRUE(HasSpan('e', 'f', option1.name(1), "name_part"));
+  EXPECT_TRUE(HasSpan('h', 'i', option1, "positive_int_value"));
 
-  EXPECT_TRUE(HasSpan("k", "n", file_.options()));
-  EXPECT_TRUE(HasSpan("l", "m", option2, "negative_int_value"));
+  EXPECT_TRUE(HasSpan('k', 'n', file_.options()));
+  EXPECT_TRUE(HasSpan('l', 'm', option2, "negative_int_value"));
 
-  EXPECT_TRUE(HasSpan("o", "r", file_.options()));
-  EXPECT_TRUE(HasSpan("p", "q", option3, "identifier_value"));
+  EXPECT_TRUE(HasSpan('o', 'r', file_.options()));
+  EXPECT_TRUE(HasSpan('p', 'q', option3, "identifier_value"));
 
-  EXPECT_TRUE(HasSpan("s", "v", file_.options()));
-  EXPECT_TRUE(HasSpan("t", "u", option4, "string_value"));
+  EXPECT_TRUE(HasSpan('s', 'v', file_.options()));
+  EXPECT_TRUE(HasSpan('t', 'u', option4, "string_value"));
 
-  EXPECT_TRUE(HasSpan("w", "z", file_.options()));
-  EXPECT_TRUE(HasSpan("x", "y", option5, "aggregate_value"));
+  EXPECT_TRUE(HasSpan('w', 'z', file_.options()));
+  EXPECT_TRUE(HasSpan('x', 'y', option5, "aggregate_value"));
 
-  EXPECT_TRUE(HasSpan("0", "3", file_.options()));
-  EXPECT_TRUE(HasSpan("1", "2", option6, "double_value"));
+  EXPECT_TRUE(HasSpan('0', '3', file_.options()));
+  EXPECT_TRUE(HasSpan('1', '2', option6, "double_value"));
 
   // Ignore these.
   EXPECT_TRUE(HasSpan(file_));
@@ -1967,22 +2098,22 @@ TEST_F(SourceInfoTest, Options) {
 TEST_F(SourceInfoTest, ScopedOptions) {
   EXPECT_TRUE(Parse(
     "message Foo {\n"
-    "  /*a*/option mopt = 1;/*b*/\n"
+    "  $a$option mopt = 1;$b$\n"
     "}\n"
     "enum Bar {\n"
-    "  /*c*/option eopt = 1;/*d*/\n"
+    "  $c$option eopt = 1;$d$\n"
     "}\n"
     "service Baz {\n"
-    "  /*e*/option sopt = 1;/*f*/\n"
+    "  $e$option sopt = 1;$f$\n"
     "  rpc M(X) returns(Y) {\n"
-    "    /*g*/option mopt = 1;/*h*/\n"
+    "    $g$option mopt = 1;$h$\n"
     "  }\n"
     "}\n"));
 
-  EXPECT_TRUE(HasSpan("a", "b", file_.message_type(0).options()));
-  EXPECT_TRUE(HasSpan("c", "d", file_.enum_type(0).options()));
-  EXPECT_TRUE(HasSpan("e", "f", file_.service(0).options()));
-  EXPECT_TRUE(HasSpan("g", "h", file_.service(0).method(0).options()));
+  EXPECT_TRUE(HasSpan('a', 'b', file_.message_type(0).options()));
+  EXPECT_TRUE(HasSpan('c', 'd', file_.enum_type(0).options()));
+  EXPECT_TRUE(HasSpan('e', 'f', file_.service(0).options()));
+  EXPECT_TRUE(HasSpan('g', 'h', file_.service(0).method(0).options()));
 
   // Ignore these.
   EXPECT_TRUE(HasSpan(file_));
@@ -2045,8 +2176,8 @@ TEST_F(SourceInfoTest, FieldOptions) {
   EXPECT_TRUE(Parse(
       "message Foo {"
       "  optional int32 bar = 1 "
-          "/*a*/[default=/*b*/123/*c*/,/*d*/opt1=123/*e*/,"
-          "/*f*/opt2='hi'/*g*/]/*h*/;"
+          "$a$[default=$b$123$c$,$d$opt1=123$e$,"
+          "$f$opt2='hi'$g$]$h$;"
       "}\n"
   ));
 
@@ -2054,10 +2185,10 @@ TEST_F(SourceInfoTest, FieldOptions) {
   const UninterpretedOption& option1 = field.options().uninterpreted_option(0);
   const UninterpretedOption& option2 = field.options().uninterpreted_option(1);
 
-  EXPECT_TRUE(HasSpan("a", "h", field.options()));
-  EXPECT_TRUE(HasSpan("b", "c", field, "default_value"));
-  EXPECT_TRUE(HasSpan("d", "e", option1));
-  EXPECT_TRUE(HasSpan("f", "g", option2));
+  EXPECT_TRUE(HasSpan('a', 'h', field.options()));
+  EXPECT_TRUE(HasSpan('b', 'c', field, "default_value"));
+  EXPECT_TRUE(HasSpan('d', 'e', option1));
+  EXPECT_TRUE(HasSpan('f', 'g', option2));
 
   // Ignore these.
   EXPECT_TRUE(HasSpan(file_));
@@ -2084,7 +2215,7 @@ TEST_F(SourceInfoTest, EnumValueOptions) {
   // syntax used for enum options is understood.
   EXPECT_TRUE(Parse(
       "enum Foo {"
-      "  BAR = 1 /*a*/[/*b*/opt1=123/*c*/,/*d*/opt2='hi'/*e*/]/*f*/;"
+      "  BAR = 1 $a$[$b$opt1=123$c$,$d$opt2='hi'$e$]$f$;"
       "}\n"
   ));
 
@@ -2092,9 +2223,9 @@ TEST_F(SourceInfoTest, EnumValueOptions) {
   const UninterpretedOption& option1 = value.options().uninterpreted_option(0);
   const UninterpretedOption& option2 = value.options().uninterpreted_option(1);
 
-  EXPECT_TRUE(HasSpan("a", "f", value.options()));
-  EXPECT_TRUE(HasSpan("b", "c", option1));
-  EXPECT_TRUE(HasSpan("d", "e", option2));
+  EXPECT_TRUE(HasSpan('a', 'f', value.options()));
+  EXPECT_TRUE(HasSpan('b', 'c', option1));
+  EXPECT_TRUE(HasSpan('d', 'e', option2));
 
   // Ignore these.
   EXPECT_TRUE(HasSpan(file_));
@@ -2113,6 +2244,127 @@ TEST_F(SourceInfoTest, EnumValueOptions) {
   EXPECT_TRUE(HasSpan(option2, "string_value"));
 }
 
+TEST_F(SourceInfoTest, DocComments) {
+  EXPECT_TRUE(Parse(
+      "// Foo leading\n"
+      "// line 2\n"
+      "$a$message Foo {\n"
+      "  // Foo trailing\n"
+      "  // line 2\n"
+      "\n"
+      "  // ignored\n"
+      "\n"
+      "  // bar leading\n"
+      "  $b$optional int32 bar = 1;$c$\n"
+      "  // bar trailing\n"
+      "}$d$\n"
+      "// ignored\n"
+  ));
+
+  const DescriptorProto& foo = file_.message_type(0);
+  const FieldDescriptorProto& bar = foo.field(0);
+
+  EXPECT_TRUE(HasSpanWithComment('a', 'd', foo,
+      " Foo leading\n line 2\n",
+      " Foo trailing\n line 2\n"));
+  EXPECT_TRUE(HasSpanWithComment('b', 'c', bar,
+      " bar leading\n",
+      " bar trailing\n"));
+
+  // Ignore these.
+  EXPECT_TRUE(HasSpan(file_));
+  EXPECT_TRUE(HasSpan(foo, "name"));
+  EXPECT_TRUE(HasSpan(bar, "label"));
+  EXPECT_TRUE(HasSpan(bar, "type"));
+  EXPECT_TRUE(HasSpan(bar, "name"));
+  EXPECT_TRUE(HasSpan(bar, "number"));
+}
+
+TEST_F(SourceInfoTest, DocComments2) {
+  EXPECT_TRUE(Parse(
+      "// ignored\n"
+      "syntax = \"proto2\";\n"
+      "// Foo leading\n"
+      "// line 2\n"
+      "$a$message Foo {\n"
+      "  /* Foo trailing\n"
+      "   * line 2 */\n"
+      "  // ignored\n"
+      "  /* bar leading\n"
+      "   */"
+      "  $b$optional int32 bar = 1;$c$  // bar trailing\n"
+      "  // ignored\n"
+      "}$d$\n"
+      "// ignored\n"
+      "\n"
+      "// option leading\n"
+      "$e$option baz = 123;$f$\n"
+      "// option trailing\n"
+  ));
+
+  const DescriptorProto& foo = file_.message_type(0);
+  const FieldDescriptorProto& bar = foo.field(0);
+  const UninterpretedOption& baz = file_.options().uninterpreted_option(0);
+
+  EXPECT_TRUE(HasSpanWithComment('a', 'd', foo,
+      " Foo leading\n line 2\n",
+      " Foo trailing\n line 2 "));
+  EXPECT_TRUE(HasSpanWithComment('b', 'c', bar,
+      " bar leading\n",
+      " bar trailing\n"));
+  EXPECT_TRUE(HasSpanWithComment('e', 'f', baz,
+      " option leading\n",
+      " option trailing\n"));
+
+  // Ignore these.
+  EXPECT_TRUE(HasSpan(file_));
+  EXPECT_TRUE(HasSpan(foo, "name"));
+  EXPECT_TRUE(HasSpan(bar, "label"));
+  EXPECT_TRUE(HasSpan(bar, "type"));
+  EXPECT_TRUE(HasSpan(bar, "name"));
+  EXPECT_TRUE(HasSpan(bar, "number"));
+  EXPECT_TRUE(HasSpan(file_.options()));
+  EXPECT_TRUE(HasSpan(baz, "name"));
+  EXPECT_TRUE(HasSpan(baz.name(0)));
+  EXPECT_TRUE(HasSpan(baz.name(0), "name_part"));
+  EXPECT_TRUE(HasSpan(baz, "positive_int_value"));
+}
+
+TEST_F(SourceInfoTest, DocComments3) {
+  EXPECT_TRUE(Parse(
+      "$a$message Foo {\n"
+      "  // bar leading\n"
+      "  $b$optional int32 bar = 1 [(baz.qux) = {}];$c$\n"
+      "  // bar trailing\n"
+      "}$d$\n"
+      "// ignored\n"
+  ));
+
+  const DescriptorProto& foo = file_.message_type(0);
+  const FieldDescriptorProto& bar = foo.field(0);
+
+  EXPECT_TRUE(HasSpanWithComment('b', 'c', bar,
+      " bar leading\n",
+      " bar trailing\n"));
+
+  // Ignore these.
+  EXPECT_TRUE(HasSpan(file_));
+  EXPECT_TRUE(HasSpan(foo));
+  EXPECT_TRUE(HasSpan(foo, "name"));
+  EXPECT_TRUE(HasSpan(bar, "label"));
+  EXPECT_TRUE(HasSpan(bar, "type"));
+  EXPECT_TRUE(HasSpan(bar, "name"));
+  EXPECT_TRUE(HasSpan(bar, "number"));
+  EXPECT_TRUE(HasSpan(bar.options()));
+  EXPECT_TRUE(HasSpan(bar.options().uninterpreted_option(0)));
+  EXPECT_TRUE(HasSpan(bar.options().uninterpreted_option(0), "name"));
+  EXPECT_TRUE(HasSpan(bar.options().uninterpreted_option(0).name(0)));
+  EXPECT_TRUE(HasSpan(
+      bar.options().uninterpreted_option(0).name(0), "name_part"));
+  EXPECT_TRUE(HasSpan(
+      bar.options().uninterpreted_option(0), "aggregate_value"));
+}
+
 // ===================================================================
 
 }  // anonymous namespace
diff --git a/src/google/protobuf/compiler/plugin.h b/src/google/protobuf/compiler/plugin.h
index 7c403332..6fa2de12 100644
--- a/src/google/protobuf/compiler/plugin.h
+++ b/src/google/protobuf/compiler/plugin.h
@@ -56,7 +56,6 @@
 #define GOOGLE_PROTOBUF_COMPILER_PLUGIN_H__
 
 #include <google/protobuf/stubs/common.h>
-
 namespace google {
 namespace protobuf {
 namespace compiler {
diff --git a/src/google/protobuf/compiler/plugin.pb.cc b/src/google/protobuf/compiler/plugin.pb.cc
index 05ff2f04..bc0c1f17 100644
--- a/src/google/protobuf/compiler/plugin.pb.cc
+++ b/src/google/protobuf/compiler/plugin.pb.cc
@@ -1,4 +1,5 @@
 // Generated by the protocol buffer compiler.  DO NOT EDIT!
+// source: google/protobuf/compiler/plugin.proto
 
 #define INTERNAL_SUPPRESS_PROTOBUF_FIELD_DEPRECATION
 #include "google/protobuf/compiler/plugin.pb.h"
@@ -9,6 +10,7 @@
 #include <google/protobuf/io/coded_stream.h>
 #include <google/protobuf/wire_format_lite_inl.h>
 #include <google/protobuf/descriptor.h>
+#include <google/protobuf/generated_message_reflection.h>
 #include <google/protobuf/reflection_ops.h>
 #include <google/protobuf/wire_format.h>
 // @@protoc_insertion_point(includes)
@@ -124,6 +126,7 @@ void protobuf_AddDesc_google_2fprotobuf_2fcompiler_2fplugin_2eproto() {
   if (already_here) return;
   already_here = true;
   GOOGLE_PROTOBUF_VERIFY_VERSION;
+
   ::google::protobuf::protobuf_AddDesc_google_2fprotobuf_2fdescriptor_2eproto();
   ::google::protobuf::DescriptorPool::InternalAddGeneratedFile(
     "\n%google/protobuf/compiler/plugin.proto\022"
@@ -253,7 +256,7 @@ bool CodeGeneratorRequest::MergePartialFromCodedStream(
         if (input->ExpectTag(18)) goto parse_parameter;
         break;
       }
-      
+
       // optional string parameter = 2;
       case 2: {
         if (::google::protobuf::internal::WireFormatLite::GetTagWireType(tag) ==
@@ -270,7 +273,7 @@ bool CodeGeneratorRequest::MergePartialFromCodedStream(
         if (input->ExpectTag(122)) goto parse_proto_file;
         break;
       }
-      
+
       // repeated .google.protobuf.FileDescriptorProto proto_file = 15;
       case 15: {
         if (::google::protobuf::internal::WireFormatLite::GetTagWireType(tag) ==
@@ -285,7 +288,7 @@ bool CodeGeneratorRequest::MergePartialFromCodedStream(
         if (input->ExpectAtEnd()) return true;
         break;
       }
-      
+
       default: {
       handle_uninterpreted:
         if (::google::protobuf::internal::WireFormatLite::GetTagWireType(tag) ==
@@ -312,7 +315,7 @@ void CodeGeneratorRequest::SerializeWithCachedSizes(
     ::google::protobuf::internal::WireFormatLite::WriteString(
       1, this->file_to_generate(i), output);
   }
-  
+
   // optional string parameter = 2;
   if (has_parameter()) {
     ::google::protobuf::internal::WireFormat::VerifyUTF8String(
@@ -321,13 +324,13 @@ void CodeGeneratorRequest::SerializeWithCachedSizes(
     ::google::protobuf::internal::WireFormatLite::WriteString(
       2, this->parameter(), output);
   }
-  
+
   // repeated .google.protobuf.FileDescriptorProto proto_file = 15;
   for (int i = 0; i < this->proto_file_size(); i++) {
     ::google::protobuf::internal::WireFormatLite::WriteMessageMaybeToArray(
       15, this->proto_file(i), output);
   }
-  
+
   if (!unknown_fields().empty()) {
     ::google::protobuf::internal::WireFormat::SerializeUnknownFields(
         unknown_fields(), output);
@@ -344,7 +347,7 @@ void CodeGeneratorRequest::SerializeWithCachedSizes(
     target = ::google::protobuf::internal::WireFormatLite::
       WriteStringToArray(1, this->file_to_generate(i), target);
   }
-  
+
   // optional string parameter = 2;
   if (has_parameter()) {
     ::google::protobuf::internal::WireFormat::VerifyUTF8String(
@@ -354,14 +357,14 @@ void CodeGeneratorRequest::SerializeWithCachedSizes(
       ::google::protobuf::internal::WireFormatLite::WriteStringToArray(
         2, this->parameter(), target);
   }
-  
+
   // repeated .google.protobuf.FileDescriptorProto proto_file = 15;
   for (int i = 0; i < this->proto_file_size(); i++) {
     target = ::google::protobuf::internal::WireFormatLite::
       WriteMessageNoVirtualToArray(
         15, this->proto_file(i), target);
   }
-  
+
   if (!unknown_fields().empty()) {
     target = ::google::protobuf::internal::WireFormat::SerializeUnknownFieldsToArray(
         unknown_fields(), target);
@@ -371,7 +374,7 @@ void CodeGeneratorRequest::SerializeWithCachedSizes(
 
 int CodeGeneratorRequest::ByteSize() const {
   int total_size = 0;
-  
+
   if (_has_bits_[1 / 32] & (0xffu << (1 % 32))) {
     // optional string parameter = 2;
     if (has_parameter()) {
@@ -379,7 +382,7 @@ int CodeGeneratorRequest::ByteSize() const {
         ::google::protobuf::internal::WireFormatLite::StringSize(
           this->parameter());
     }
-    
+
   }
   // repeated string file_to_generate = 1;
   total_size += 1 * this->file_to_generate_size();
@@ -387,7 +390,7 @@ int CodeGeneratorRequest::ByteSize() const {
     total_size += ::google::protobuf::internal::WireFormatLite::StringSize(
       this->file_to_generate(i));
   }
-  
+
   // repeated .google.protobuf.FileDescriptorProto proto_file = 15;
   total_size += 1 * this->proto_file_size();
   for (int i = 0; i < this->proto_file_size(); i++) {
@@ -395,7 +398,7 @@ int CodeGeneratorRequest::ByteSize() const {
       ::google::protobuf::internal::WireFormatLite::MessageSizeNoVirtual(
         this->proto_file(i));
   }
-  
+
   if (!unknown_fields().empty()) {
     total_size +=
       ::google::protobuf::internal::WireFormat::ComputeUnknownFieldsSize(
@@ -444,7 +447,7 @@ void CodeGeneratorRequest::CopyFrom(const CodeGeneratorRequest& from) {
 }
 
 bool CodeGeneratorRequest::IsInitialized() const {
-  
+
   for (int i = 0; i < proto_file_size(); i++) {
     if (!this->proto_file(i).IsInitialized()) return false;
   }
@@ -583,7 +586,7 @@ bool CodeGeneratorResponse_File::MergePartialFromCodedStream(
         if (input->ExpectTag(18)) goto parse_insertion_point;
         break;
       }
-      
+
       // optional string insertion_point = 2;
       case 2: {
         if (::google::protobuf::internal::WireFormatLite::GetTagWireType(tag) ==
@@ -600,7 +603,7 @@ bool CodeGeneratorResponse_File::MergePartialFromCodedStream(
         if (input->ExpectTag(122)) goto parse_content;
         break;
       }
-      
+
       // optional string content = 15;
       case 15: {
         if (::google::protobuf::internal::WireFormatLite::GetTagWireType(tag) ==
@@ -617,7 +620,7 @@ bool CodeGeneratorResponse_File::MergePartialFromCodedStream(
         if (input->ExpectAtEnd()) return true;
         break;
       }
-      
+
       default: {
       handle_uninterpreted:
         if (::google::protobuf::internal::WireFormatLite::GetTagWireType(tag) ==
@@ -644,7 +647,7 @@ void CodeGeneratorResponse_File::SerializeWithCachedSizes(
     ::google::protobuf::internal::WireFormatLite::WriteString(
       1, this->name(), output);
   }
-  
+
   // optional string insertion_point = 2;
   if (has_insertion_point()) {
     ::google::protobuf::internal::WireFormat::VerifyUTF8String(
@@ -653,7 +656,7 @@ void CodeGeneratorResponse_File::SerializeWithCachedSizes(
     ::google::protobuf::internal::WireFormatLite::WriteString(
       2, this->insertion_point(), output);
   }
-  
+
   // optional string content = 15;
   if (has_content()) {
     ::google::protobuf::internal::WireFormat::VerifyUTF8String(
@@ -662,7 +665,7 @@ void CodeGeneratorResponse_File::SerializeWithCachedSizes(
     ::google::protobuf::internal::WireFormatLite::WriteString(
       15, this->content(), output);
   }
-  
+
   if (!unknown_fields().empty()) {
     ::google::protobuf::internal::WireFormat::SerializeUnknownFields(
         unknown_fields(), output);
@@ -680,7 +683,7 @@ void CodeGeneratorResponse_File::SerializeWithCachedSizes(
       ::google::protobuf::internal::WireFormatLite::WriteStringToArray(
         1, this->name(), target);
   }
-  
+
   // optional string insertion_point = 2;
   if (has_insertion_point()) {
     ::google::protobuf::internal::WireFormat::VerifyUTF8String(
@@ -690,7 +693,7 @@ void CodeGeneratorResponse_File::SerializeWithCachedSizes(
       ::google::protobuf::internal::WireFormatLite::WriteStringToArray(
         2, this->insertion_point(), target);
   }
-  
+
   // optional string content = 15;
   if (has_content()) {
     ::google::protobuf::internal::WireFormat::VerifyUTF8String(
@@ -700,7 +703,7 @@ void CodeGeneratorResponse_File::SerializeWithCachedSizes(
       ::google::protobuf::internal::WireFormatLite::WriteStringToArray(
         15, this->content(), target);
   }
-  
+
   if (!unknown_fields().empty()) {
     target = ::google::protobuf::internal::WireFormat::SerializeUnknownFieldsToArray(
         unknown_fields(), target);
@@ -710,7 +713,7 @@ void CodeGeneratorResponse_File::SerializeWithCachedSizes(
 
 int CodeGeneratorResponse_File::ByteSize() const {
   int total_size = 0;
-  
+
   if (_has_bits_[0 / 32] & (0xffu << (0 % 32))) {
     // optional string name = 1;
     if (has_name()) {
@@ -718,21 +721,21 @@ int CodeGeneratorResponse_File::ByteSize() const {
         ::google::protobuf::internal::WireFormatLite::StringSize(
           this->name());
     }
-    
+
     // optional string insertion_point = 2;
     if (has_insertion_point()) {
       total_size += 1 +
         ::google::protobuf::internal::WireFormatLite::StringSize(
           this->insertion_point());
     }
-    
+
     // optional string content = 15;
     if (has_content()) {
       total_size += 1 +
         ::google::protobuf::internal::WireFormatLite::StringSize(
           this->content());
     }
-    
+
   }
   if (!unknown_fields().empty()) {
     total_size +=
@@ -786,7 +789,7 @@ void CodeGeneratorResponse_File::CopyFrom(const CodeGeneratorResponse_File& from
 }
 
 bool CodeGeneratorResponse_File::IsInitialized() const {
-  
+
   return true;
 }
 
@@ -904,7 +907,7 @@ bool CodeGeneratorResponse::MergePartialFromCodedStream(
         if (input->ExpectTag(122)) goto parse_file;
         break;
       }
-      
+
       // repeated .google.protobuf.compiler.CodeGeneratorResponse.File file = 15;
       case 15: {
         if (::google::protobuf::internal::WireFormatLite::GetTagWireType(tag) ==
@@ -919,7 +922,7 @@ bool CodeGeneratorResponse::MergePartialFromCodedStream(
         if (input->ExpectAtEnd()) return true;
         break;
       }
-      
+
       default: {
       handle_uninterpreted:
         if (::google::protobuf::internal::WireFormatLite::GetTagWireType(tag) ==
@@ -946,13 +949,13 @@ void CodeGeneratorResponse::SerializeWithCachedSizes(
     ::google::protobuf::internal::WireFormatLite::WriteString(
       1, this->error(), output);
   }
-  
+
   // repeated .google.protobuf.compiler.CodeGeneratorResponse.File file = 15;
   for (int i = 0; i < this->file_size(); i++) {
     ::google::protobuf::internal::WireFormatLite::WriteMessageMaybeToArray(
       15, this->file(i), output);
   }
-  
+
   if (!unknown_fields().empty()) {
     ::google::protobuf::internal::WireFormat::SerializeUnknownFields(
         unknown_fields(), output);
@@ -970,14 +973,14 @@ void CodeGeneratorResponse::SerializeWithCachedSizes(
       ::google::protobuf::internal::WireFormatLite::WriteStringToArray(
         1, this->error(), target);
   }
-  
+
   // repeated .google.protobuf.compiler.CodeGeneratorResponse.File file = 15;
   for (int i = 0; i < this->file_size(); i++) {
     target = ::google::protobuf::internal::WireFormatLite::
       WriteMessageNoVirtualToArray(
         15, this->file(i), target);
   }
-  
+
   if (!unknown_fields().empty()) {
     target = ::google::protobuf::internal::WireFormat::SerializeUnknownFieldsToArray(
         unknown_fields(), target);
@@ -987,7 +990,7 @@ void CodeGeneratorResponse::SerializeWithCachedSizes(
 
 int CodeGeneratorResponse::ByteSize() const {
   int total_size = 0;
-  
+
   if (_has_bits_[0 / 32] & (0xffu << (0 % 32))) {
     // optional string error = 1;
     if (has_error()) {
@@ -995,7 +998,7 @@ int CodeGeneratorResponse::ByteSize() const {
         ::google::protobuf::internal::WireFormatLite::StringSize(
           this->error());
     }
-    
+
   }
   // repeated .google.protobuf.compiler.CodeGeneratorResponse.File file = 15;
   total_size += 1 * this->file_size();
@@ -1004,7 +1007,7 @@ int CodeGeneratorResponse::ByteSize() const {
       ::google::protobuf::internal::WireFormatLite::MessageSizeNoVirtual(
         this->file(i));
   }
-  
+
   if (!unknown_fields().empty()) {
     total_size +=
       ::google::protobuf::internal::WireFormat::ComputeUnknownFieldsSize(
@@ -1052,7 +1055,7 @@ void CodeGeneratorResponse::CopyFrom(const CodeGeneratorResponse& from) {
 }
 
 bool CodeGeneratorResponse::IsInitialized() const {
-  
+
   return true;
 }
 
diff --git a/src/google/protobuf/compiler/plugin.pb.h b/src/google/protobuf/compiler/plugin.pb.h
index 1cf8a556..46478c73 100644
--- a/src/google/protobuf/compiler/plugin.pb.h
+++ b/src/google/protobuf/compiler/plugin.pb.h
@@ -20,9 +20,10 @@
 #endif
 
 #include <google/protobuf/generated_message_util.h>
+#include <google/protobuf/message.h>
 #include <google/protobuf/repeated_field.h>
 #include <google/protobuf/extension_set.h>
-#include <google/protobuf/generated_message_reflection.h>
+#include <google/protobuf/unknown_field_set.h>
 #include "google/protobuf/descriptor.pb.h"
 // @@protoc_insertion_point(includes)
 
@@ -45,29 +46,29 @@ class LIBPROTOC_EXPORT CodeGeneratorRequest : public ::google::protobuf::Message
  public:
   CodeGeneratorRequest();
   virtual ~CodeGeneratorRequest();
-  
+
   CodeGeneratorRequest(const CodeGeneratorRequest& from);
-  
+
   inline CodeGeneratorRequest& operator=(const CodeGeneratorRequest& from) {
     CopyFrom(from);
     return *this;
   }
-  
+
   inline const ::google::protobuf::UnknownFieldSet& unknown_fields() const {
     return _unknown_fields_;
   }
-  
+
   inline ::google::protobuf::UnknownFieldSet* mutable_unknown_fields() {
     return &_unknown_fields_;
   }
-  
+
   static const ::google::protobuf::Descriptor* descriptor();
   static const CodeGeneratorRequest& default_instance();
-  
+
   void Swap(CodeGeneratorRequest* other);
-  
+
   // implements Message ----------------------------------------------
-  
+
   CodeGeneratorRequest* New() const;
   void CopyFrom(const ::google::protobuf::Message& from);
   void MergeFrom(const ::google::protobuf::Message& from);
@@ -75,7 +76,7 @@ class LIBPROTOC_EXPORT CodeGeneratorRequest : public ::google::protobuf::Message
   void MergeFrom(const CodeGeneratorRequest& from);
   void Clear();
   bool IsInitialized() const;
-  
+
   int ByteSize() const;
   bool MergePartialFromCodedStream(
       ::google::protobuf::io::CodedInputStream* input);
@@ -88,13 +89,13 @@ class LIBPROTOC_EXPORT CodeGeneratorRequest : public ::google::protobuf::Message
   void SharedDtor();
   void SetCachedSize(int size) const;
   public:
-  
+
   ::google::protobuf::Metadata GetMetadata() const;
-  
+
   // nested types ----------------------------------------------------
-  
+
   // accessors -------------------------------------------------------
-  
+
   // repeated string file_to_generate = 1;
   inline int file_to_generate_size() const;
   inline void clear_file_to_generate();
@@ -110,7 +111,7 @@ class LIBPROTOC_EXPORT CodeGeneratorRequest : public ::google::protobuf::Message
   inline void add_file_to_generate(const char* value, size_t size);
   inline const ::google::protobuf::RepeatedPtrField< ::std::string>& file_to_generate() const;
   inline ::google::protobuf::RepeatedPtrField< ::std::string>* mutable_file_to_generate();
-  
+
   // optional string parameter = 2;
   inline bool has_parameter() const;
   inline void clear_parameter();
@@ -121,7 +122,8 @@ class LIBPROTOC_EXPORT CodeGeneratorRequest : public ::google::protobuf::Message
   inline void set_parameter(const char* value, size_t size);
   inline ::std::string* mutable_parameter();
   inline ::std::string* release_parameter();
-  
+  inline void set_allocated_parameter(::std::string* parameter);
+
   // repeated .google.protobuf.FileDescriptorProto proto_file = 15;
   inline int proto_file_size() const;
   inline void clear_proto_file();
@@ -133,25 +135,25 @@ class LIBPROTOC_EXPORT CodeGeneratorRequest : public ::google::protobuf::Message
       proto_file() const;
   inline ::google::protobuf::RepeatedPtrField< ::google::protobuf::FileDescriptorProto >*
       mutable_proto_file();
-  
+
   // @@protoc_insertion_point(class_scope:google.protobuf.compiler.CodeGeneratorRequest)
  private:
   inline void set_has_parameter();
   inline void clear_has_parameter();
-  
+
   ::google::protobuf::UnknownFieldSet _unknown_fields_;
-  
+
   ::google::protobuf::RepeatedPtrField< ::std::string> file_to_generate_;
   ::std::string* parameter_;
   ::google::protobuf::RepeatedPtrField< ::google::protobuf::FileDescriptorProto > proto_file_;
-  
+
   mutable int _cached_size_;
   ::google::protobuf::uint32 _has_bits_[(3 + 31) / 32];
-  
+
   friend void LIBPROTOC_EXPORT protobuf_AddDesc_google_2fprotobuf_2fcompiler_2fplugin_2eproto();
   friend void protobuf_AssignDesc_google_2fprotobuf_2fcompiler_2fplugin_2eproto();
   friend void protobuf_ShutdownFile_google_2fprotobuf_2fcompiler_2fplugin_2eproto();
-  
+
   void InitAsDefaultInstance();
   static CodeGeneratorRequest* default_instance_;
 };
@@ -161,29 +163,29 @@ class LIBPROTOC_EXPORT CodeGeneratorResponse_File : public ::google::protobuf::M
  public:
   CodeGeneratorResponse_File();
   virtual ~CodeGeneratorResponse_File();
-  
+
   CodeGeneratorResponse_File(const CodeGeneratorResponse_File& from);
-  
+
   inline CodeGeneratorResponse_File& operator=(const CodeGeneratorResponse_File& from) {
     CopyFrom(from);
     return *this;
   }
-  
+
   inline const ::google::protobuf::UnknownFieldSet& unknown_fields() const {
     return _unknown_fields_;
   }
-  
+
   inline ::google::protobuf::UnknownFieldSet* mutable_unknown_fields() {
     return &_unknown_fields_;
   }
-  
+
   static const ::google::protobuf::Descriptor* descriptor();
   static const CodeGeneratorResponse_File& default_instance();
-  
+
   void Swap(CodeGeneratorResponse_File* other);
-  
+
   // implements Message ----------------------------------------------
-  
+
   CodeGeneratorResponse_File* New() const;
   void CopyFrom(const ::google::protobuf::Message& from);
   void MergeFrom(const ::google::protobuf::Message& from);
@@ -191,7 +193,7 @@ class LIBPROTOC_EXPORT CodeGeneratorResponse_File : public ::google::protobuf::M
   void MergeFrom(const CodeGeneratorResponse_File& from);
   void Clear();
   bool IsInitialized() const;
-  
+
   int ByteSize() const;
   bool MergePartialFromCodedStream(
       ::google::protobuf::io::CodedInputStream* input);
@@ -204,13 +206,13 @@ class LIBPROTOC_EXPORT CodeGeneratorResponse_File : public ::google::protobuf::M
   void SharedDtor();
   void SetCachedSize(int size) const;
   public:
-  
+
   ::google::protobuf::Metadata GetMetadata() const;
-  
+
   // nested types ----------------------------------------------------
-  
+
   // accessors -------------------------------------------------------
-  
+
   // optional string name = 1;
   inline bool has_name() const;
   inline void clear_name();
@@ -221,7 +223,8 @@ class LIBPROTOC_EXPORT CodeGeneratorResponse_File : public ::google::protobuf::M
   inline void set_name(const char* value, size_t size);
   inline ::std::string* mutable_name();
   inline ::std::string* release_name();
-  
+  inline void set_allocated_name(::std::string* name);
+
   // optional string insertion_point = 2;
   inline bool has_insertion_point() const;
   inline void clear_insertion_point();
@@ -232,7 +235,8 @@ class LIBPROTOC_EXPORT CodeGeneratorResponse_File : public ::google::protobuf::M
   inline void set_insertion_point(const char* value, size_t size);
   inline ::std::string* mutable_insertion_point();
   inline ::std::string* release_insertion_point();
-  
+  inline void set_allocated_insertion_point(::std::string* insertion_point);
+
   // optional string content = 15;
   inline bool has_content() const;
   inline void clear_content();
@@ -243,7 +247,8 @@ class LIBPROTOC_EXPORT CodeGeneratorResponse_File : public ::google::protobuf::M
   inline void set_content(const char* value, size_t size);
   inline ::std::string* mutable_content();
   inline ::std::string* release_content();
-  
+  inline void set_allocated_content(::std::string* content);
+
   // @@protoc_insertion_point(class_scope:google.protobuf.compiler.CodeGeneratorResponse.File)
  private:
   inline void set_has_name();
@@ -252,20 +257,20 @@ class LIBPROTOC_EXPORT CodeGeneratorResponse_File : public ::google::protobuf::M
   inline void clear_has_insertion_point();
   inline void set_has_content();
   inline void clear_has_content();
-  
+
   ::google::protobuf::UnknownFieldSet _unknown_fields_;
-  
+
   ::std::string* name_;
   ::std::string* insertion_point_;
   ::std::string* content_;
-  
+
   mutable int _cached_size_;
   ::google::protobuf::uint32 _has_bits_[(3 + 31) / 32];
-  
+
   friend void LIBPROTOC_EXPORT protobuf_AddDesc_google_2fprotobuf_2fcompiler_2fplugin_2eproto();
   friend void protobuf_AssignDesc_google_2fprotobuf_2fcompiler_2fplugin_2eproto();
   friend void protobuf_ShutdownFile_google_2fprotobuf_2fcompiler_2fplugin_2eproto();
-  
+
   void InitAsDefaultInstance();
   static CodeGeneratorResponse_File* default_instance_;
 };
@@ -275,29 +280,29 @@ class LIBPROTOC_EXPORT CodeGeneratorResponse : public ::google::protobuf::Messag
  public:
   CodeGeneratorResponse();
   virtual ~CodeGeneratorResponse();
-  
+
   CodeGeneratorResponse(const CodeGeneratorResponse& from);
-  
+
   inline CodeGeneratorResponse& operator=(const CodeGeneratorResponse& from) {
     CopyFrom(from);
     return *this;
   }
-  
+
   inline const ::google::protobuf::UnknownFieldSet& unknown_fields() const {
     return _unknown_fields_;
   }
-  
+
   inline ::google::protobuf::UnknownFieldSet* mutable_unknown_fields() {
     return &_unknown_fields_;
   }
-  
+
   static const ::google::protobuf::Descriptor* descriptor();
   static const CodeGeneratorResponse& default_instance();
-  
+
   void Swap(CodeGeneratorResponse* other);
-  
+
   // implements Message ----------------------------------------------
-  
+
   CodeGeneratorResponse* New() const;
   void CopyFrom(const ::google::protobuf::Message& from);
   void MergeFrom(const ::google::protobuf::Message& from);
@@ -305,7 +310,7 @@ class LIBPROTOC_EXPORT CodeGeneratorResponse : public ::google::protobuf::Messag
   void MergeFrom(const CodeGeneratorResponse& from);
   void Clear();
   bool IsInitialized() const;
-  
+
   int ByteSize() const;
   bool MergePartialFromCodedStream(
       ::google::protobuf::io::CodedInputStream* input);
@@ -318,15 +323,15 @@ class LIBPROTOC_EXPORT CodeGeneratorResponse : public ::google::protobuf::Messag
   void SharedDtor();
   void SetCachedSize(int size) const;
   public:
-  
+
   ::google::protobuf::Metadata GetMetadata() const;
-  
+
   // nested types ----------------------------------------------------
-  
+
   typedef CodeGeneratorResponse_File File;
-  
+
   // accessors -------------------------------------------------------
-  
+
   // optional string error = 1;
   inline bool has_error() const;
   inline void clear_error();
@@ -337,7 +342,8 @@ class LIBPROTOC_EXPORT CodeGeneratorResponse : public ::google::protobuf::Messag
   inline void set_error(const char* value, size_t size);
   inline ::std::string* mutable_error();
   inline ::std::string* release_error();
-  
+  inline void set_allocated_error(::std::string* error);
+
   // repeated .google.protobuf.compiler.CodeGeneratorResponse.File file = 15;
   inline int file_size() const;
   inline void clear_file();
@@ -349,24 +355,24 @@ class LIBPROTOC_EXPORT CodeGeneratorResponse : public ::google::protobuf::Messag
       file() const;
   inline ::google::protobuf::RepeatedPtrField< ::google::protobuf::compiler::CodeGeneratorResponse_File >*
       mutable_file();
-  
+
   // @@protoc_insertion_point(class_scope:google.protobuf.compiler.CodeGeneratorResponse)
  private:
   inline void set_has_error();
   inline void clear_has_error();
-  
+
   ::google::protobuf::UnknownFieldSet _unknown_fields_;
-  
+
   ::std::string* error_;
   ::google::protobuf::RepeatedPtrField< ::google::protobuf::compiler::CodeGeneratorResponse_File > file_;
-  
+
   mutable int _cached_size_;
   ::google::protobuf::uint32 _has_bits_[(2 + 31) / 32];
-  
+
   friend void LIBPROTOC_EXPORT protobuf_AddDesc_google_2fprotobuf_2fcompiler_2fplugin_2eproto();
   friend void protobuf_AssignDesc_google_2fprotobuf_2fcompiler_2fplugin_2eproto();
   friend void protobuf_ShutdownFile_google_2fprotobuf_2fcompiler_2fplugin_2eproto();
-  
+
   void InitAsDefaultInstance();
   static CodeGeneratorResponse* default_instance_;
 };
@@ -478,6 +484,18 @@ inline ::std::string* CodeGeneratorRequest::release_parameter() {
     return temp;
   }
 }
+inline void CodeGeneratorRequest::set_allocated_parameter(::std::string* parameter) {
+  if (parameter_ != &::google::protobuf::internal::kEmptyString) {
+    delete parameter_;
+  }
+  if (parameter) {
+    set_has_parameter();
+    parameter_ = parameter;
+  } else {
+    clear_has_parameter();
+    parameter_ = const_cast< ::std::string*>(&::google::protobuf::internal::kEmptyString);
+  }
+}
 
 // repeated .google.protobuf.FileDescriptorProto proto_file = 15;
 inline int CodeGeneratorRequest::proto_file_size() const {
@@ -565,6 +583,18 @@ inline ::std::string* CodeGeneratorResponse_File::release_name() {
     return temp;
   }
 }
+inline void CodeGeneratorResponse_File::set_allocated_name(::std::string* name) {
+  if (name_ != &::google::protobuf::internal::kEmptyString) {
+    delete name_;
+  }
+  if (name) {
+    set_has_name();
+    name_ = name;
+  } else {
+    clear_has_name();
+    name_ = const_cast< ::std::string*>(&::google::protobuf::internal::kEmptyString);
+  }
+}
 
 // optional string insertion_point = 2;
 inline bool CodeGeneratorResponse_File::has_insertion_point() const {
@@ -623,6 +653,18 @@ inline ::std::string* CodeGeneratorResponse_File::release_insertion_point() {
     return temp;
   }
 }
+inline void CodeGeneratorResponse_File::set_allocated_insertion_point(::std::string* insertion_point) {
+  if (insertion_point_ != &::google::protobuf::internal::kEmptyString) {
+    delete insertion_point_;
+  }
+  if (insertion_point) {
+    set_has_insertion_point();
+    insertion_point_ = insertion_point;
+  } else {
+    clear_has_insertion_point();
+    insertion_point_ = const_cast< ::std::string*>(&::google::protobuf::internal::kEmptyString);
+  }
+}
 
 // optional string content = 15;
 inline bool CodeGeneratorResponse_File::has_content() const {
@@ -681,6 +723,18 @@ inline ::std::string* CodeGeneratorResponse_File::release_content() {
     return temp;
   }
 }
+inline void CodeGeneratorResponse_File::set_allocated_content(::std::string* content) {
+  if (content_ != &::google::protobuf::internal::kEmptyString) {
+    delete content_;
+  }
+  if (content) {
+    set_has_content();
+    content_ = content;
+  } else {
+    clear_has_content();
+    content_ = const_cast< ::std::string*>(&::google::protobuf::internal::kEmptyString);
+  }
+}
 
 // -------------------------------------------------------------------
 
@@ -743,6 +797,18 @@ inline ::std::string* CodeGeneratorResponse::release_error() {
     return temp;
   }
 }
+inline void CodeGeneratorResponse::set_allocated_error(::std::string* error) {
+  if (error_ != &::google::protobuf::internal::kEmptyString) {
+    delete error_;
+  }
+  if (error) {
+    set_has_error();
+    error_ = error;
+  } else {
+    clear_has_error();
+    error_ = const_cast< ::std::string*>(&::google::protobuf::internal::kEmptyString);
+  }
+}
 
 // repeated .google.protobuf.compiler.CodeGeneratorResponse.File file = 15;
 inline int CodeGeneratorResponse::file_size() const {
diff --git a/src/google/protobuf/compiler/python/python_generator.cc b/src/google/protobuf/compiler/python/python_generator.cc
index 9b109378..211ac70c 100644
--- a/src/google/protobuf/compiler/python/python_generator.cc
+++ b/src/google/protobuf/compiler/python/python_generator.cc
@@ -52,6 +52,7 @@
 #include <google/protobuf/descriptor.pb.h>
 
 #include <google/protobuf/stubs/common.h>
+#include <google/protobuf/stubs/stringprintf.h>
 #include <google/protobuf/io/printer.h>
 #include <google/protobuf/descriptor.h>
 #include <google/protobuf/io/zero_copy_stream.h>
@@ -106,6 +107,12 @@ string NamePrefixedWithNestedTypes(const DescriptorT& descriptor,
 const char kDescriptorKey[] = "DESCRIPTOR";
 
 
+// Does the file have top-level enums?
+inline bool HasTopLevelEnums(const FileDescriptor *file) {
+  return file->enum_type_count() > 0;
+}
+
+
 // Should we generate generic services for this file?
 inline bool HasGenericServices(const FileDescriptor *file) {
   return file->service_count() > 0 &&
@@ -120,13 +127,21 @@ void PrintTopBoilerplate(
   // TODO(robinson): Allow parameterization of Python version?
   printer->Print(
       "# Generated by the protocol buffer compiler.  DO NOT EDIT!\n"
-      "\n"
-      "from google.protobuf import descriptor\n"
-      "from google.protobuf import message\n"
-      "from google.protobuf import reflection\n");
+      "# source: $filename$\n"
+      "\n",
+      "filename", file->name());
+  if (HasTopLevelEnums(file)) {
+    printer->Print(
+        "from google.protobuf.internal import enum_type_wrapper\n");
+  }
+  printer->Print(
+      "from google.protobuf import descriptor as _descriptor\n"
+      "from google.protobuf import message as _message\n"
+      "from google.protobuf import reflection as _reflection\n"
+      );
   if (HasGenericServices(file)) {
     printer->Print(
-        "from google.protobuf import service\n"
+        "from google.protobuf import service as _service\n"
         "from google.protobuf import service_reflection\n");
   }
 
@@ -204,12 +219,12 @@ string StringifyDefaultValue(const FieldDescriptor& field) {
     case FieldDescriptor::CPPTYPE_STRING:
       if (field.type() == FieldDescriptor::TYPE_STRING) {
         return "unicode(\"" + CEscape(field.default_value_string()) +
-            "\", \"utf-8\")";
+                        "\", \"utf-8\")";
       } else {
         return "\"" + CEscape(field.default_value_string()) + "\"";
       }
-    case FieldDescriptor::CPPTYPE_MESSAGE:
-      return "None";
+      case FieldDescriptor::CPPTYPE_MESSAGE:
+          return "None";
   }
   // (We could add a default case above but then we wouldn't get the nice
   // compiler warning when a new type is added.)
@@ -270,6 +285,11 @@ bool Generator::Generate(const FileDescriptor* file,
   // since they need to call static RegisterExtension() methods on these
   // classes.
   FixForeignFieldsInExtensions();
+  // Descriptor options may have custom extensions. These custom options
+  // can only be successfully parsed after we register corresponding
+  // extensions. Therefore we parse all options again here to recognize
+  // custom options that may be unknown when we define the descriptors.
+  FixAllDescriptorOptions();
   if (HasGenericServices(file)) {
     PrintServices();
   }
@@ -288,6 +308,13 @@ void Generator::PrintImports() const {
                     module_name);
   }
   printer_->Print("\n");
+
+  // Print public imports.
+  for (int i = 0; i < file_->public_dependency_count(); ++i) {
+    string module_name = ModuleName(file_->public_dependency(i)->name());
+    printer_->Print("from $module$ import *\n", "module", module_name);
+  }
+  printer_->Print("\n");
 }
 
 // Prints the single file descriptor for this file.
@@ -297,7 +324,7 @@ void Generator::PrintFileDescriptor() const {
   m["name"] = file_->name();
   m["package"] = file_->package();
   const char file_descriptor_template[] =
-      "$descriptor_name$ = descriptor.FileDescriptor(\n"
+      "$descriptor_name$ = _descriptor.FileDescriptor(\n"
       "  name='$name$',\n"
       "  package='$package$',\n";
   printer_->Print(m, file_descriptor_template);
@@ -321,6 +348,11 @@ void Generator::PrintTopLevelEnums() const {
   for (int i = 0; i < file_->enum_type_count(); ++i) {
     const EnumDescriptor& enum_descriptor = *file_->enum_type(i);
     PrintEnum(enum_descriptor);
+    printer_->Print("$name$ = "
+                    "enum_type_wrapper.EnumTypeWrapper($descriptor_name$)",
+                    "name", enum_descriptor.name(),
+                    "descriptor_name",
+                    ModuleLevelDescriptorName(enum_descriptor));
     printer_->Print("\n");
 
     for (int j = 0; j < enum_descriptor.value_count(); ++j) {
@@ -355,7 +387,7 @@ void Generator::PrintEnum(const EnumDescriptor& enum_descriptor) const {
   m["full_name"] = enum_descriptor.full_name();
   m["file"] = kDescriptorKey;
   const char enum_descriptor_template[] =
-      "$descriptor_name$ = descriptor.EnumDescriptor(\n"
+      "$descriptor_name$ = _descriptor.EnumDescriptor(\n"
       "  name='$name$',\n"
       "  full_name='$full_name$',\n"
       "  filename=None,\n"
@@ -436,7 +468,7 @@ void Generator::PrintServiceDescriptor(
   descriptor.options().SerializeToString(&options_string);
 
   printer_->Print(
-      "$service_name$ = descriptor.ServiceDescriptor(\n",
+      "$service_name$ = _descriptor.ServiceDescriptor(\n",
       "service_name", service_name);
   printer_->Indent();
   map<string, string> m;
@@ -459,7 +491,6 @@ void Generator::PrintServiceDescriptor(
   printer_->Print("methods=[\n");
   for (int i = 0; i < descriptor.method_count(); ++i) {
     const MethodDescriptor* method = descriptor.method(i);
-    string options_string;
     method->options().SerializeToString(&options_string);
 
     m.clear();
@@ -470,7 +501,7 @@ void Generator::PrintServiceDescriptor(
     m["input_type"] = ModuleLevelDescriptorName(*(method->input_type()));
     m["output_type"] = ModuleLevelDescriptorName(*(method->output_type()));
     m["options_value"] = OptionsValue("MethodOptions", options_string);
-    printer_->Print("descriptor.MethodDescriptor(\n");
+    printer_->Print("_descriptor.MethodDescriptor(\n");
     printer_->Indent();
     printer_->Print(
         m,
@@ -491,7 +522,7 @@ void Generator::PrintServiceDescriptor(
 
 void Generator::PrintServiceClass(const ServiceDescriptor& descriptor) const {
   // Print the service.
-  printer_->Print("class $class_name$(service.Service):\n",
+  printer_->Print("class $class_name$(_service.Service):\n",
                   "class_name", descriptor.name());
   printer_->Indent();
   printer_->Print(
@@ -523,7 +554,7 @@ void Generator::PrintDescriptor(const Descriptor& message_descriptor) const {
   PrintNestedDescriptors(message_descriptor);
 
   printer_->Print("\n");
-  printer_->Print("$descriptor_name$ = descriptor.Descriptor(\n",
+  printer_->Print("$descriptor_name$ = _descriptor.Descriptor(\n",
                   "descriptor_name",
                   ModuleLevelDescriptorName(message_descriptor));
   printer_->Indent();
@@ -618,10 +649,10 @@ void Generator::PrintMessages() const {
 // Mutually recursive with PrintNestedMessages().
 void Generator::PrintMessage(
     const Descriptor& message_descriptor) const {
-  printer_->Print("class $name$(message.Message):\n", "name",
+  printer_->Print("class $name$(_message.Message):\n", "name",
                   message_descriptor.name());
   printer_->Indent();
-  printer_->Print("__metaclass__ = reflection.GeneratedProtocolMessageType\n");
+  printer_->Print("__metaclass__ = _reflection.GeneratedProtocolMessageType\n");
   PrintNestedMessages(message_descriptor);
   map<string, string> m;
   m["descriptor_key"] = kDescriptorKey;
@@ -779,6 +810,7 @@ void Generator::FixForeignFieldsInExtensions() const {
   for (int i = 0; i < file_->message_type_count(); ++i) {
     FixForeignFieldsInNestedExtensions(*file_->message_type(i));
   }
+  printer_->Print("\n");
 }
 
 void Generator::FixForeignFieldsInExtension(
@@ -829,7 +861,7 @@ void Generator::PrintEnumValueDescriptor(
   m["options"] = OptionsValue("EnumValueOptions", options_string);
   printer_->Print(
       m,
-      "descriptor.EnumValueDescriptor(\n"
+      "_descriptor.EnumValueDescriptor(\n"
       "  name='$name$', index=$index$, number=$number$,\n"
       "  options=$options$,\n"
       "  type=None)");
@@ -843,7 +875,7 @@ string Generator::OptionsValue(
     return "None";
   } else {
     string full_class_name = "descriptor_pb2." + class_name;
-    return "descriptor._ParseOptions(" + full_class_name + "(), '"
+    return "_descriptor._ParseOptions(" + full_class_name + "(), '"
         + CEscape(serialized_options)+ "')";
   }
 }
@@ -869,7 +901,7 @@ void Generator::PrintFieldDescriptor(
   // these fields in correctly after all referenced descriptors have been
   // defined and/or imported (see FixForeignFieldsInDescriptors()).
   const char field_descriptor_decl[] =
-    "descriptor.FieldDescriptor(\n"
+    "_descriptor.FieldDescriptor(\n"
     "  name='$name$', full_name='$full_name$', index=$index$,\n"
     "  number=$number$, type=$type$, cpp_type=$cpp_type$, label=$label$,\n"
     "  has_default_value=$has_default_value$, default_value=$default_value$,\n"
@@ -1000,6 +1032,125 @@ void Generator::PrintSerializedPbInterval(
                   "serialized_end", SimpleItoa(offset + sp.size()));
 }
 
+namespace {
+void PrintDescriptorOptionsFixingCode(const string& descriptor,
+                                      const string& options,
+                                      io::Printer* printer) {
+  // TODO(xiaofeng): I have added a method _SetOptions() to DescriptorBase
+  // in proto2 python runtime but it couldn't be used here because appengine
+  // uses a snapshot version of the library in which the new method is not
+  // yet present. After appengine has synced their runtime library, the code
+  // below should be cleaned up to use _SetOptions().
+  printer->Print(
+      "$descriptor$.has_options = True\n"
+      "$descriptor$._options = $options$\n",
+      "descriptor", descriptor, "options", options);
+}
+}  // namespace
+
+// Prints expressions that set the options field of all descriptors.
+void Generator::FixAllDescriptorOptions() const {
+  // Prints an expression that sets the file descriptor's options.
+  string file_options = OptionsValue(
+      "FileOptions", file_->options().SerializeAsString());
+  if (file_options != "None") {
+    PrintDescriptorOptionsFixingCode(kDescriptorKey, file_options, printer_);
+  }
+  // Prints expressions that set the options for all top level enums.
+  for (int i = 0; i < file_->enum_type_count(); ++i) {
+    const EnumDescriptor& enum_descriptor = *file_->enum_type(i);
+    FixOptionsForEnum(enum_descriptor);
+  }
+  // Prints expressions that set the options for all top level extensions.
+  for (int i = 0; i < file_->extension_count(); ++i) {
+    const FieldDescriptor& field = *file_->extension(i);
+    FixOptionsForField(field);
+  }
+  // Prints expressions that set the options for all messages, nested enums,
+  // nested extensions and message fields.
+  for (int i = 0; i < file_->message_type_count(); ++i) {
+    FixOptionsForMessage(*file_->message_type(i));
+  }
+}
+
+// Prints expressions that set the options for an enum descriptor and its
+// value descriptors.
+void Generator::FixOptionsForEnum(const EnumDescriptor& enum_descriptor) const {
+  string descriptor_name = ModuleLevelDescriptorName(enum_descriptor);
+  string enum_options = OptionsValue(
+      "EnumOptions", enum_descriptor.options().SerializeAsString());
+  if (enum_options != "None") {
+    PrintDescriptorOptionsFixingCode(descriptor_name, enum_options, printer_);
+  }
+  for (int i = 0; i < enum_descriptor.value_count(); ++i) {
+    const EnumValueDescriptor& value_descriptor = *enum_descriptor.value(i);
+    string value_options = OptionsValue(
+        "EnumValueOptions", value_descriptor.options().SerializeAsString());
+    if (value_options != "None") {
+      PrintDescriptorOptionsFixingCode(
+          StringPrintf("%s.values_by_name[\"%s\"]", descriptor_name.c_str(),
+                       value_descriptor.name().c_str()),
+          value_options, printer_);
+    }
+  }
+}
+
+// Prints expressions that set the options for field descriptors (including
+// extensions).
+void Generator::FixOptionsForField(
+    const FieldDescriptor& field) const {
+  string field_options = OptionsValue(
+      "FieldOptions", field.options().SerializeAsString());
+  if (field_options != "None") {
+    string field_name;
+    if (field.is_extension()) {
+      if (field.extension_scope() == NULL) {
+        // Top level extensions.
+        field_name = field.name();
+      } else {
+        field_name = FieldReferencingExpression(
+            field.extension_scope(), field, "extensions_by_name");
+      }
+    } else {
+      field_name = FieldReferencingExpression(
+          field.containing_type(), field, "fields_by_name");
+    }
+    PrintDescriptorOptionsFixingCode(field_name, field_options, printer_);
+  }
+}
+
+// Prints expressions that set the options for a message and all its inner
+// types (nested messages, nested enums, extensions, fields).
+void Generator::FixOptionsForMessage(const Descriptor& descriptor) const {
+  // Nested messages.
+  for (int i = 0; i < descriptor.nested_type_count(); ++i) {
+    FixOptionsForMessage(*descriptor.nested_type(i));
+  }
+  // Enums.
+  for (int i = 0; i < descriptor.enum_type_count(); ++i) {
+    FixOptionsForEnum(*descriptor.enum_type(i));
+  }
+  // Fields.
+  for (int i = 0; i < descriptor.field_count(); ++i) {
+    const FieldDescriptor& field = *descriptor.field(i);
+    FixOptionsForField(field);
+  }
+  // Extensions.
+  for (int i = 0; i < descriptor.extension_count(); ++i) {
+    const FieldDescriptor& field = *descriptor.extension(i);
+    FixOptionsForField(field);
+  }
+  // Message option for this message.
+  string message_options = OptionsValue(
+      "MessageOptions", descriptor.options().SerializeAsString());
+  if (message_options != "None") {
+    string descriptor_name = ModuleLevelDescriptorName(descriptor);
+    PrintDescriptorOptionsFixingCode(descriptor_name,
+                                     message_options,
+                                     printer_);
+  }
+}
+
 }  // namespace python
 }  // namespace compiler
 }  // namespace protobuf
diff --git a/src/google/protobuf/compiler/python/python_generator.h b/src/google/protobuf/compiler/python/python_generator.h
index 84eaf8ab..a3f22cee 100644
--- a/src/google/protobuf/compiler/python/python_generator.h
+++ b/src/google/protobuf/compiler/python/python_generator.h
@@ -138,6 +138,11 @@ class LIBPROTOC_EXPORT Generator : public CodeGenerator {
   void PrintSerializedPbInterval(
       const DescriptorT& descriptor, DescriptorProtoT& proto) const;
 
+  void FixAllDescriptorOptions() const;
+  void FixOptionsForField(const FieldDescriptor& field) const;
+  void FixOptionsForEnum(const EnumDescriptor& descriptor) const;
+  void FixOptionsForMessage(const Descriptor& descriptor) const;
+
   // Very coarse-grained lock to ensure that Generate() is reentrant.
   // Guards file_, printer_ and file_descriptor_serialized_.
   mutable Mutex mutex_;
diff --git a/src/google/protobuf/compiler/subprocess.cc b/src/google/protobuf/compiler/subprocess.cc
index 5fb5d5cb..860fc875 100644
--- a/src/google/protobuf/compiler/subprocess.cc
+++ b/src/google/protobuf/compiler/subprocess.cc
@@ -33,6 +33,7 @@
 #include <google/protobuf/compiler/subprocess.h>
 
 #include <algorithm>
+#include <iostream>
 
 #ifndef _WIN32
 #include <errno.h>
diff --git a/src/google/protobuf/compiler/subprocess.h b/src/google/protobuf/compiler/subprocess.h
index 00564964..de9fce9e 100644
--- a/src/google/protobuf/compiler/subprocess.h
+++ b/src/google/protobuf/compiler/subprocess.h
@@ -53,7 +53,7 @@ class Message;
 namespace compiler {
 
 // Utility class for launching sub-processes.
-class LIBPROTOC_EXPORT Subprocess {
+class Subprocess {
  public:
   Subprocess();
   ~Subprocess();