Down integrate from Google internal branch for C++ and Java.

- Maps for C++ lite
- C++ Arena optimizations.
- Java Lite runtime code size optimization.

Change-Id: I7537a4357c1cb385d23f9e8aa7ffdfeefe079f13

18 files changed, 601 insertions, 357 deletions

diff --git a/src/google/protobuf/compiler/cpp/cpp_bootstrap_unittest.cc b/src/google/protobuf/compiler/cpp/cpp_bootstrap_unittest.cc
index 48788197..13ed0b64 100644
--- a/src/google/protobuf/compiler/cpp/cpp_bootstrap_unittest.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_bootstrap_unittest.cc
@@ -98,7 +98,8 @@ class MockGeneratorContext : public GeneratorContext {
                           &actual_contents, true));
     EXPECT_TRUE(actual_contents == *expected_contents)
       << physical_filename << " needs to be regenerated.  Please run "
-         "generate_descriptor_proto.sh and add this file "
+         "google/protobuf/compiler/release_compiler.sh and "
+         "generate_descriptor_proto.sh. Then add this file "
          "to your CL.";
   }
 
diff --git a/src/google/protobuf/compiler/cpp/cpp_enum.cc b/src/google/protobuf/compiler/cpp/cpp_enum.cc
index 3ce1f120..0404b739 100644
--- a/src/google/protobuf/compiler/cpp/cpp_enum.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_enum.cc
@@ -47,7 +47,7 @@ namespace cpp {
 
 namespace {
 // The GOOGLE_ARRAYSIZE constant is the max enum value plus 1. If the max enum value
-// is kint32max, GOOGLE_ARRAYSIZE will overflow. In such cases we should omit the
+// is ::google::protobuf::kint32max, GOOGLE_ARRAYSIZE will overflow. In such cases we should omit the
 // generation of the GOOGLE_ARRAYSIZE constant.
 bool ShouldGenerateArraySize(const EnumDescriptor* descriptor) {
   int32 max_value = descriptor->value(0)->number();
@@ -56,7 +56,7 @@ bool ShouldGenerateArraySize(const EnumDescriptor* descriptor) {
       max_value = descriptor->value(i)->number();
     }
   }
-  return max_value != kint32max;
+  return max_value != ::google::protobuf::kint32max;
 }
 }  // namespace
 
@@ -153,9 +153,12 @@ void EnumGenerator::GenerateDefinition(io::Printer* printer) {
 
 void EnumGenerator::
 GenerateGetEnumDescriptorSpecializations(io::Printer* printer) {
+  printer->Print(
+      "template <> struct is_proto_enum< $classname$> : ::google::protobuf::internal::true_type "
+      "{};\n",
+      "classname", ClassName(descriptor_, true));
   if (HasDescriptorMethods(descriptor_->file())) {
     printer->Print(
-      "template <> struct is_proto_enum< $classname$> : ::google::protobuf::internal::true_type {};\n"
       "template <>\n"
       "inline const EnumDescriptor* GetEnumDescriptor< $classname$>() {\n"
       "  return $classname$_descriptor();\n"
diff --git a/src/google/protobuf/compiler/cpp/cpp_enum_field.cc b/src/google/protobuf/compiler/cpp/cpp_enum_field.cc
index 17926135..74989703 100644
--- a/src/google/protobuf/compiler/cpp/cpp_enum_field.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_enum_field.cc
@@ -76,23 +76,26 @@ GeneratePrivateMembers(io::Printer* printer) const {
 void EnumFieldGenerator::
 GenerateAccessorDeclarations(io::Printer* printer) const {
   printer->Print(variables_,
-    "inline $type$ $name$() const$deprecation$;\n"
-    "inline void set_$name$($type$ value)$deprecation$;\n");
+    "$type$ $name$() const$deprecation$;\n"
+    "void set_$name$($type$ value)$deprecation$;\n");
 }
 
 void EnumFieldGenerator::
-GenerateInlineAccessorDefinitions(io::Printer* printer) const {
-  printer->Print(variables_,
-    "inline $type$ $classname$::$name$() const {\n"
+GenerateInlineAccessorDefinitions(io::Printer* printer,
+                                  bool is_inline) const {
+  map<string, string> variables(variables_);
+  variables["inline"] = is_inline ? "inline" : "";
+  printer->Print(variables,
+    "$inline$ $type$ $classname$::$name$() const {\n"
     "  // @@protoc_insertion_point(field_get:$full_name$)\n"
     "  return static_cast< $type$ >($name$_);\n"
     "}\n"
-    "inline void $classname$::set_$name$($type$ value) {\n");
+    "$inline$ void $classname$::set_$name$($type$ value) {\n");
   if (!HasPreservingUnknownEnumSemantics(descriptor_->file())) {
-    printer->Print(variables_,
+    printer->Print(variables,
     "  assert($type$_IsValid(value));\n");
   }
-  printer->Print(variables_,
+  printer->Print(variables,
     "  $set_hasbit$\n"
     "  $name$_ = value;\n"
     "  // @@protoc_insertion_point(field_set:$full_name$)\n"
@@ -181,21 +184,24 @@ EnumOneofFieldGenerator(const FieldDescriptor* descriptor,
 EnumOneofFieldGenerator::~EnumOneofFieldGenerator() {}
 
 void EnumOneofFieldGenerator::
-GenerateInlineAccessorDefinitions(io::Printer* printer) const {
-  printer->Print(variables_,
-    "inline $type$ $classname$::$name$() const {\n"
+GenerateInlineAccessorDefinitions(io::Printer* printer,
+                                  bool is_inline) const {
+  map<string, string> variables(variables_);
+  variables["inline"] = is_inline ? "inline" : "";
+  printer->Print(variables,
+    "$inline$ $type$ $classname$::$name$() const {\n"
     "  // @@protoc_insertion_point(field_get:$full_name$)\n"
     "  if (has_$name$()) {\n"
     "    return static_cast< $type$ >($oneof_prefix$$name$_);\n"
     "  }\n"
     "  return static_cast< $type$ >($default$);\n"
     "}\n"
-    "inline void $classname$::set_$name$($type$ value) {\n");
+    "$inline$ void $classname$::set_$name$($type$ value) {\n");
   if (!HasPreservingUnknownEnumSemantics(descriptor_->file())) {
-    printer->Print(variables_,
+    printer->Print(variables,
     "  assert($type$_IsValid(value));\n");
   }
-  printer->Print(variables_,
+  printer->Print(variables,
     "  if (!has_$name$()) {\n"
     "    clear_$oneof_name$();\n"
     "    set_has_$name$();\n"
@@ -246,46 +252,49 @@ GeneratePrivateMembers(io::Printer* printer) const {
 void RepeatedEnumFieldGenerator::
 GenerateAccessorDeclarations(io::Printer* printer) const {
   printer->Print(variables_,
-    "inline $type$ $name$(int index) const$deprecation$;\n"
-    "inline void set_$name$(int index, $type$ value)$deprecation$;\n"
-    "inline void add_$name$($type$ value)$deprecation$;\n");
+    "$type$ $name$(int index) const$deprecation$;\n"
+    "void set_$name$(int index, $type$ value)$deprecation$;\n"
+    "void add_$name$($type$ value)$deprecation$;\n");
   printer->Print(variables_,
-    "inline const ::google::protobuf::RepeatedField<int>& $name$() const$deprecation$;\n"
-    "inline ::google::protobuf::RepeatedField<int>* mutable_$name$()$deprecation$;\n");
+    "const ::google::protobuf::RepeatedField<int>& $name$() const$deprecation$;\n"
+    "::google::protobuf::RepeatedField<int>* mutable_$name$()$deprecation$;\n");
 }
 
 void RepeatedEnumFieldGenerator::
-GenerateInlineAccessorDefinitions(io::Printer* printer) const {
-  printer->Print(variables_,
-    "inline $type$ $classname$::$name$(int index) const {\n"
+GenerateInlineAccessorDefinitions(io::Printer* printer,
+                                  bool is_inline) const {
+  map<string, string> variables(variables_);
+  variables["inline"] = is_inline ? "inline" : "";
+  printer->Print(variables,
+    "$inline$ $type$ $classname$::$name$(int index) const {\n"
     "  // @@protoc_insertion_point(field_get:$full_name$)\n"
     "  return static_cast< $type$ >($name$_.Get(index));\n"
     "}\n"
-    "inline void $classname$::set_$name$(int index, $type$ value) {\n");
+    "$inline$ void $classname$::set_$name$(int index, $type$ value) {\n");
   if (!HasPreservingUnknownEnumSemantics(descriptor_->file())) {
-    printer->Print(variables_,
+    printer->Print(variables,
     "  assert($type$_IsValid(value));\n");
   }
-  printer->Print(variables_,
+  printer->Print(variables,
     "  $name$_.Set(index, value);\n"
     "  // @@protoc_insertion_point(field_set:$full_name$)\n"
     "}\n"
-    "inline void $classname$::add_$name$($type$ value) {\n");
+    "$inline$ void $classname$::add_$name$($type$ value) {\n");
   if (!HasPreservingUnknownEnumSemantics(descriptor_->file())) {
-    printer->Print(variables_,
+    printer->Print(variables,
     "  assert($type$_IsValid(value));\n");
   }
-  printer->Print(variables_,
+  printer->Print(variables,
     "  $name$_.Add(value);\n"
     "  // @@protoc_insertion_point(field_add:$full_name$)\n"
     "}\n");
-  printer->Print(variables_,
-    "inline const ::google::protobuf::RepeatedField<int>&\n"
+  printer->Print(variables,
+    "$inline$ const ::google::protobuf::RepeatedField<int>&\n"
     "$classname$::$name$() const {\n"
     "  // @@protoc_insertion_point(field_list:$full_name$)\n"
     "  return $name$_;\n"
     "}\n"
-    "inline ::google::protobuf::RepeatedField<int>*\n"
+    "$inline$ ::google::protobuf::RepeatedField<int>*\n"
     "$classname$::mutable_$name$() {\n"
     "  // @@protoc_insertion_point(field_mutable_list:$full_name$)\n"
     "  return &$name$_;\n"
@@ -344,20 +353,34 @@ GenerateMergeFromCodedStream(io::Printer* printer) const {
 void RepeatedEnumFieldGenerator::
 GenerateMergeFromCodedStreamWithPacking(io::Printer* printer) const {
   if (!descriptor_->options().packed()) {
-    // We use a non-inlined implementation in this case, since this path will
-    // rarely be executed.
-    printer->Print(variables_,
-      "DO_((::google::protobuf::internal::WireFormatLite::ReadPackedEnumNoInline(\n"
-      "       input,\n");
+      // This path is rarely executed, so we use a non-inlined implementation.
     if (HasPreservingUnknownEnumSemantics(descriptor_->file())) {
       printer->Print(variables_,
-      "       NULL,\n");
+        "DO_((::google::protobuf::internal::"
+                    "WireFormatLite::ReadPackedEnumPreserveUnknowns(\n"
+        "       input,\n"
+        "       $number$,\n"
+        "       NULL,\n"
+        "       NULL,\n"
+        "       this->mutable_$name$())));\n");
+    } else if (UseUnknownFieldSet(descriptor_->file())) {
+      printer->Print(variables_,
+        "DO_((::google::protobuf::internal::WireFormat::ReadPackedEnumPreserveUnknowns(\n"
+        "       input,\n"
+        "       $number$,\n"
+        "       $type$_IsValid,\n"
+        "       mutable_unknown_fields(),\n"
+        "       this->mutable_$name$())));\n");
     } else {
       printer->Print(variables_,
-      "       &$type$_IsValid,\n");
+        "DO_((::google::protobuf::internal::"
+                     "WireFormatLite::ReadPackedEnumPreserveUnknowns(\n"
+        "       input,\n"
+        "       $number$,\n"
+        "       $type$_IsValid,\n"
+        "       &unknown_fields_stream,\n"
+        "       this->mutable_$name$())));\n");
     }
-    printer->Print(variables_,
-      "       this->mutable_$name$())));\n");
   } else {
     printer->Print(variables_,
       "::google::protobuf::uint32 length;\n"
@@ -376,6 +399,16 @@ GenerateMergeFromCodedStreamWithPacking(io::Printer* printer) const {
       printer->Print(variables_,
       "  if ($type$_IsValid(value)) {\n"
       "    add_$name$(static_cast< $type$ >(value));\n"
+      "  } else {\n");
+      if (UseUnknownFieldSet(descriptor_->file())) {
+        printer->Print(variables_,
+        "    mutable_unknown_fields()->AddVarint($number$, value);\n");
+      } else {
+        printer->Print(variables_,
+        "    unknown_fields_stream.WriteVarint32(tag);\n"
+        "    unknown_fields_stream.WriteVarint32(value);\n");
+      }
+      printer->Print(
       "  }\n");
     }
     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 def2b232..5b1d01ea 100644
--- a/src/google/protobuf/compiler/cpp/cpp_enum_field.h
+++ b/src/google/protobuf/compiler/cpp/cpp_enum_field.h
@@ -53,7 +53,8 @@ class EnumFieldGenerator : public FieldGenerator {
   // implements FieldGenerator ---------------------------------------
   void GeneratePrivateMembers(io::Printer* printer) const;
   void GenerateAccessorDeclarations(io::Printer* printer) const;
-  void GenerateInlineAccessorDefinitions(io::Printer* printer) const;
+  void GenerateInlineAccessorDefinitions(io::Printer* printer,
+                                         bool is_inline) const;
   void GenerateClearingCode(io::Printer* printer) const;
   void GenerateMergingCode(io::Printer* printer) const;
   void GenerateSwappingCode(io::Printer* printer) const;
@@ -78,7 +79,8 @@ class EnumOneofFieldGenerator : public EnumFieldGenerator {
   ~EnumOneofFieldGenerator();
 
   // implements FieldGenerator ---------------------------------------
-  void GenerateInlineAccessorDefinitions(io::Printer* printer) const;
+  void GenerateInlineAccessorDefinitions(io::Printer* printer,
+                                         bool is_inline) const;
   void GenerateClearingCode(io::Printer* printer) const;
   void GenerateSwappingCode(io::Printer* printer) const;
   void GenerateConstructorCode(io::Printer* printer) const;
@@ -96,7 +98,8 @@ class RepeatedEnumFieldGenerator : public FieldGenerator {
   // implements FieldGenerator ---------------------------------------
   void GeneratePrivateMembers(io::Printer* printer) const;
   void GenerateAccessorDeclarations(io::Printer* printer) const;
-  void GenerateInlineAccessorDefinitions(io::Printer* printer) const;
+  void GenerateInlineAccessorDefinitions(io::Printer* printer,
+                                         bool is_inline) const;
   void GenerateClearingCode(io::Printer* printer) const;
   void GenerateMergingCode(io::Printer* printer) const;
   void GenerateSwappingCode(io::Printer* printer) const;
diff --git a/src/google/protobuf/compiler/cpp/cpp_field.h b/src/google/protobuf/compiler/cpp/cpp_field.h
index c37fe0be..cd2b6b75 100644
--- a/src/google/protobuf/compiler/cpp/cpp_field.h
+++ b/src/google/protobuf/compiler/cpp/cpp_field.h
@@ -89,7 +89,7 @@ class FieldGenerator {
   // Generate inline definitions of accessor functions for this field.
   // These are placed inside the header after all class definitions.
   virtual void GenerateInlineAccessorDefinitions(
-    io::Printer* printer) const = 0;
+    io::Printer* printer, bool is_inline) const = 0;
 
   // Generate definitions of accessors that aren't inlined.  These are
   // placed somewhere in the .cc file.
diff --git a/src/google/protobuf/compiler/cpp/cpp_file.cc b/src/google/protobuf/compiler/cpp/cpp_file.cc
index fae4df40..a98c7d92 100644
--- a/src/google/protobuf/compiler/cpp/cpp_file.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_file.cc
@@ -136,8 +136,11 @@ void FileGenerator::GenerateHeader(io::Printer* printer) {
   printer->Print(
     "#include <google/protobuf/arena.h>\n"
     "#include <google/protobuf/arenastring.h>\n"
-    "#include <google/protobuf/generated_message_util.h>\n"
-    "#include <google/protobuf/metadata.h>\n");
+    "#include <google/protobuf/generated_message_util.h>\n");
+  if (UseUnknownFieldSet(file_)) {
+    printer->Print(
+      "#include <google/protobuf/metadata.h>\n");
+  }
   if (file_->message_type_count() > 0) {
     if (HasDescriptorMethods(file_)) {
       printer->Print(
@@ -152,13 +155,24 @@ void FileGenerator::GenerateHeader(io::Printer* printer) {
     "#include <google/protobuf/extension_set.h>\n");
   if (HasMapFields(file_)) {
     printer->Print(
-      "#include <google/protobuf/map.h>\n"
-      "#include <google/protobuf/map_field_inl.h>\n");
+        "#include <google/protobuf/map.h>\n");
+    if (HasDescriptorMethods(file_)) {
+      printer->Print(
+          "#include <google/protobuf/map_field_inl.h>\n");
+    } else {
+      printer->Print(
+          "#include <google/protobuf/map_field_lite.h>\n");
+    }
   }
 
-  if (HasDescriptorMethods(file_) && HasEnumDefinitions(file_)) {
-    printer->Print(
-      "#include <google/protobuf/generated_enum_reflection.h>\n");
+  if (HasEnumDefinitions(file_)) {
+    if (HasDescriptorMethods(file_)) {
+      printer->Print(
+          "#include <google/protobuf/generated_enum_reflection.h>\n");
+    } else {
+      printer->Print(
+          "#include <google/protobuf/generated_enum_util.h>\n");
+    }
   }
 
   if (HasGenericServices(file_)) {
@@ -272,15 +286,17 @@ void FileGenerator::GenerateHeader(io::Printer* printer) {
   printer->Print(kThickSeparator);
   printer->Print("\n");
 
-
+  printer->Print("#if !PROTOBUF_INLINE_NOT_IN_HEADERS\n");
   // Generate class inline methods.
   for (int i = 0; i < file_->message_type_count(); i++) {
     if (i > 0) {
       printer->Print(kThinSeparator);
       printer->Print("\n");
     }
-    message_generators_[i]->GenerateInlineMethods(printer);
+    message_generators_[i]->GenerateInlineMethods(printer,
+                                                  /* is_inline = */ true);
   }
+  printer->Print("#endif  // !PROTOBUF_INLINE_NOT_IN_HEADERS\n");
 
   printer->Print(
     "\n"
@@ -290,7 +306,7 @@ void FileGenerator::GenerateHeader(io::Printer* printer) {
   GenerateNamespaceClosers(printer);
 
   // Emit GetEnumDescriptor specializations into google::protobuf namespace:
-  if (HasDescriptorMethods(file_)) {
+  if (HasEnumDefinitions(file_)) {
     // The SWIG conditional is to avoid a null-pointer dereference
     // (bug 1984964) in swig-1.3.21 resulting from the following syntax:
     //   namespace X { void Y<Z::W>(); }
@@ -417,6 +433,12 @@ void FileGenerator::GenerateSource(io::Printer* printer) {
     printer->Print(kThickSeparator);
     printer->Print("\n");
     message_generators_[i]->GenerateClassMethods(printer);
+
+    printer->Print("#if PROTOBUF_INLINE_NOT_IN_HEADERS\n");
+    // Generate class inline methods.
+    message_generators_[i]->GenerateInlineMethods(printer,
+                                                  /* is_inline = */ false);
+    printer->Print("#endif  // PROTOBUF_INLINE_NOT_IN_HEADERS\n");
   }
 
   if (HasGenericServices(file_)) {
diff --git a/src/google/protobuf/compiler/cpp/cpp_helpers.cc b/src/google/protobuf/compiler/cpp/cpp_helpers.cc
index 28c4dd54..237278db 100644
--- a/src/google/protobuf/compiler/cpp/cpp_helpers.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_helpers.cc
@@ -352,9 +352,7 @@ string FilenameIdentifier(const string& filename) {
     } else {
       // Not alphanumeric.  To avoid any possibility of name conflicts we
       // use the hex code for the character.
-      result.push_back('_');
-      char buffer[kFastToBufferSize];
-      result.append(FastHexToBuffer(static_cast<uint8>(filename[i]), buffer));
+      StrAppend(&result, "_", ToHex(static_cast<uint8>(filename[i])));
     }
   }
   return result;
@@ -508,6 +506,13 @@ bool IsStringOrMessage(const FieldDescriptor* field) {
   return false;
 }
 
+FieldOptions::CType EffectiveStringCType(const FieldDescriptor* field) {
+  GOOGLE_DCHECK(field->cpp_type() == FieldDescriptor::CPPTYPE_STRING);
+  // Open-source protobuf release only supports STRING ctype.
+  return FieldOptions::STRING;
+
+}
+
 }  // 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 e60fa7c2..c7bb8f98 100644
--- a/src/google/protobuf/compiler/cpp/cpp_helpers.h
+++ b/src/google/protobuf/compiler/cpp/cpp_helpers.h
@@ -211,6 +211,10 @@ inline bool IsMapEntryMessage(const Descriptor* descriptor) {
 // Returns true if the field's CPPTYPE is string or message.
 bool IsStringOrMessage(const FieldDescriptor* field);
 
+// For a string field, returns the effective ctype.  If the actual ctype is
+// not supported, returns the default of STRING.
+FieldOptions::CType EffectiveStringCType(const FieldDescriptor* field);
+
 string UnderscoresToCamelCase(const string& input, bool cap_next_letter);
 
 inline bool HasFieldPresence(const FileDescriptor* file) {
diff --git a/src/google/protobuf/compiler/cpp/cpp_map_field.cc b/src/google/protobuf/compiler/cpp/cpp_map_field.cc
index 0154eeb8..8c38db2b 100644
--- a/src/google/protobuf/compiler/cpp/cpp_map_field.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_map_field.cc
@@ -31,6 +31,7 @@
 #include <google/protobuf/compiler/cpp/cpp_map_field.h>
 #include <google/protobuf/compiler/cpp/cpp_helpers.h>
 #include <google/protobuf/io/printer.h>
+#include <google/protobuf/wire_format.h>
 #include <google/protobuf/stubs/strutil.h>
 
 namespace google {
@@ -72,14 +73,21 @@ void SetMessageVariables(const FieldDescriptor* descriptor,
       (*variables)["val_cpp"] = PrimitiveTypeName(val->cpp_type());
       (*variables)["wrapper"] = "EntryWrapper";
   }
-  (*variables)["key_type"] =
-      "::google::protobuf::FieldDescriptor::TYPE_" +
+  (*variables)["key_wire_type"] =
+      "::google::protobuf::internal::WireFormatLite::TYPE_" +
       ToUpper(DeclaredTypeMethodName(key->type()));
-  (*variables)["val_type"] =
-      "::google::protobuf::FieldDescriptor::TYPE_" +
+  (*variables)["val_wire_type"] =
+      "::google::protobuf::internal::WireFormatLite::TYPE_" +
       ToUpper(DeclaredTypeMethodName(val->type()));
   (*variables)["map_classname"] = ClassName(descriptor->message_type(), false);
-  (*variables)["number"] = Int32ToString(descriptor->number());
+  (*variables)["number"] = SimpleItoa(descriptor->number());
+  (*variables)["tag"] = SimpleItoa(internal::WireFormat::MakeTag(descriptor));
+
+  if (HasDescriptorMethods(descriptor->file())) {
+    (*variables)["lite"] = "";
+  } else {
+    (*variables)["lite"] = "Lite";
+  }
 
   if (!IsProto3Field(descriptor) &&
       val->type() == FieldDescriptor::TYPE_ENUM) {
@@ -102,33 +110,40 @@ MapFieldGenerator::~MapFieldGenerator() {}
 void MapFieldGenerator::
 GeneratePrivateMembers(io::Printer* printer) const {
   printer->Print(variables_,
-      "typedef ::google::protobuf::internal::MapEntry<\n"
+      "typedef ::google::protobuf::internal::MapEntryLite<\n"
       "    $key_cpp$, $val_cpp$,\n"
-      "    $key_type$,\n"
-      "    $val_type$, $default_enum_value$>\n"
+      "    $key_wire_type$,\n"
+      "    $val_wire_type$,\n"
+      "    $default_enum_value$ >\n"
       "    $map_classname$;\n"
-      "::google::protobuf::internal::MapField< $key_cpp$, $val_cpp$,"
-      "$key_type$, $val_type$, $default_enum_value$ > $name$_;\n");
+      "::google::protobuf::internal::MapField$lite$<\n"
+      "    $key_cpp$, $val_cpp$,\n"
+      "    $key_wire_type$,\n"
+      "    $val_wire_type$,\n"
+      "    $default_enum_value$ > $name$_;\n");
 }
 
 void MapFieldGenerator::
 GenerateAccessorDeclarations(io::Printer* printer) const {
   printer->Print(variables_,
-      "inline const ::google::protobuf::Map< $key_cpp$, $val_cpp$ >&\n"
+      "const ::google::protobuf::Map< $key_cpp$, $val_cpp$ >&\n"
       "    $name$() const$deprecation$;\n"
-      "inline ::google::protobuf::Map< $key_cpp$, $val_cpp$ >*\n"
+      "::google::protobuf::Map< $key_cpp$, $val_cpp$ >*\n"
       "    mutable_$name$()$deprecation$;\n");
 }
 
 void MapFieldGenerator::
-GenerateInlineAccessorDefinitions(io::Printer* printer) const {
-  printer->Print(variables_,
-      "inline const ::google::protobuf::Map< $key_cpp$, $val_cpp$ >&\n"
+GenerateInlineAccessorDefinitions(io::Printer* printer,
+                                  bool is_inline) const {
+  map<string, string> variables(variables_);
+  variables["inline"] = is_inline ? "inline" : "";
+  printer->Print(variables,
+      "$inline$ const ::google::protobuf::Map< $key_cpp$, $val_cpp$ >&\n"
       "$classname$::$name$() const {\n"
       "  // @@protoc_insertion_point(field_map:$full_name$)\n"
       "  return $name$_.GetMap();\n"
       "}\n"
-      "inline ::google::protobuf::Map< $key_cpp$, $val_cpp$ >*\n"
+      "$inline$ ::google::protobuf::Map< $key_cpp$, $val_cpp$ >*\n"
       "$classname$::mutable_$name$() {\n"
       "  // @@protoc_insertion_point(field_mutable_map:$full_name$)\n"
       "  return $name$_.MutableMap();\n"
@@ -198,11 +213,29 @@ GenerateMergeFromCodedStream(io::Printer* printer) const {
         "  if ($val_cpp$_IsValid(*entry->mutable_value())) {\n"
         "    (*mutable_$name$())[entry->key()] =\n"
         "        static_cast<$val_cpp$>(*entry->mutable_value());\n"
-        "  } else {\n"
-        "    mutable_unknown_fields()->AddLengthDelimited($number$, data);\n"
+        "  } else {\n");
+    if (HasDescriptorMethods(descriptor_->file())) {
+      printer->Print(variables_,
+          "    mutable_unknown_fields()"
+          "->AddLengthDelimited($number$, data);\n");
+    } else {
+      printer->Print(variables_,
+          "    unknown_fields_stream.WriteVarint32($tag$);\n"
+          "    unknown_fields_stream.WriteVarint32(data.size());\n"
+          "    unknown_fields_stream.WriteString(data);\n");
+    }
+
+
+    printer->Print(variables_,
         "  }\n"
         "}\n");
   }
+
+  // If entry is allocated by arena, its desctructor should be avoided.
+  if (SupportsArenas(descriptor_)) {
+    printer->Print(variables_,
+        "if (entry->GetArena() != NULL) entry.release();\n");
+  }
 }
 
 void MapFieldGenerator::
@@ -211,12 +244,31 @@ GenerateSerializeWithCachedSizes(io::Printer* printer) const {
       "{\n"
       "  ::google::protobuf::scoped_ptr<$map_classname$> entry;\n"
       "  for (::google::protobuf::Map< $key_cpp$, $val_cpp$ >::const_iterator\n"
-      "      it = $name$().begin(); it != $name$().end(); ++it) {\n"
+      "      it = $name$().begin(); it != $name$().end(); ++it) {\n");
+
+  // If entry is allocated by arena, its desctructor should be avoided.
+  if (SupportsArenas(descriptor_)) {
+    printer->Print(variables_,
+        "    if (entry.get() != NULL && entry->GetArena() != NULL) {\n"
+        "      entry.release();\n"
+        "    }\n");
+  }
+
+  printer->Print(variables_,
       "    entry.reset($name$_.New$wrapper$(it->first, it->second));\n"
       "    ::google::protobuf::internal::WireFormatLite::Write$stream_writer$(\n"
       "        $number$, *entry, output);\n"
-      "  }\n"
-      "}\n");
+      "  }\n");
+
+  // If entry is allocated by arena, its desctructor should be avoided.
+  if (SupportsArenas(descriptor_)) {
+    printer->Print(variables_,
+        "  if (entry.get() != NULL && entry->GetArena() != NULL) {\n"
+        "    entry.release();\n"
+        "  }\n");
+  }
+
+  printer->Print("}\n");
 }
 
 void MapFieldGenerator::
@@ -225,13 +277,32 @@ GenerateSerializeWithCachedSizesToArray(io::Printer* printer) const {
       "{\n"
       "  ::google::protobuf::scoped_ptr<$map_classname$> entry;\n"
       "  for (::google::protobuf::Map< $key_cpp$, $val_cpp$ >::const_iterator\n"
-      "      it = $name$().begin(); it != $name$().end(); ++it) {\n"
+      "      it = $name$().begin(); it != $name$().end(); ++it) {\n");
+
+  // If entry is allocated by arena, its desctructor should be avoided.
+  if (SupportsArenas(descriptor_)) {
+    printer->Print(variables_,
+        "    if (entry.get() != NULL && entry->GetArena() != NULL) {\n"
+        "      entry.release();\n"
+        "    }\n");
+  }
+
+  printer->Print(variables_,
       "    entry.reset($name$_.New$wrapper$(it->first, it->second));\n"
       "    target = ::google::protobuf::internal::WireFormatLite::\n"
       "        Write$declared_type$NoVirtualToArray(\n"
       "            $number$, *entry, target);\n"
-      "  }\n"
-      "}\n");
+      "  }\n");
+
+  // If entry is allocated by arena, its desctructor should be avoided.
+  if (SupportsArenas(descriptor_)) {
+    printer->Print(variables_,
+        "  if (entry.get() != NULL && entry->GetArena() != NULL) {\n"
+        "    entry.release();\n"
+        "  }\n");
+  }
+
+  printer->Print("}\n");
 }
 
 void MapFieldGenerator::
@@ -241,12 +312,31 @@ GenerateByteSize(io::Printer* printer) const {
       "{\n"
       "  ::google::protobuf::scoped_ptr<$map_classname$> entry;\n"
       "  for (::google::protobuf::Map< $key_cpp$, $val_cpp$ >::const_iterator\n"
-      "      it = $name$().begin(); it != $name$().end(); ++it) {\n"
+      "      it = $name$().begin(); it != $name$().end(); ++it) {\n");
+
+  // If entry is allocated by arena, its desctructor should be avoided.
+  if (SupportsArenas(descriptor_)) {
+    printer->Print(variables_,
+        "    if (entry.get() != NULL && entry->GetArena() != NULL) {\n"
+        "      entry.release();\n"
+        "    }\n");
+  }
+
+  printer->Print(variables_,
       "    entry.reset($name$_.New$wrapper$(it->first, it->second));\n"
       "    total_size += ::google::protobuf::internal::WireFormatLite::\n"
       "        $declared_type$SizeNoVirtual(*entry);\n"
-      "  }\n"
-      "}\n");
+      "  }\n");
+
+  // If entry is allocated by arena, its desctructor should be avoided.
+  if (SupportsArenas(descriptor_)) {
+    printer->Print(variables_,
+        "  if (entry.get() != NULL && entry->GetArena() != NULL) {\n"
+        "    entry.release();\n"
+        "  }\n");
+  }
+
+  printer->Print("}\n");
 }
 
 }  // namespace cpp
diff --git a/src/google/protobuf/compiler/cpp/cpp_map_field.h b/src/google/protobuf/compiler/cpp/cpp_map_field.h
index 0ff032fd..d27d4851 100644
--- a/src/google/protobuf/compiler/cpp/cpp_map_field.h
+++ b/src/google/protobuf/compiler/cpp/cpp_map_field.h
@@ -50,7 +50,8 @@ class MapFieldGenerator : public FieldGenerator {
   // implements FieldGenerator ---------------------------------------
   void GeneratePrivateMembers(io::Printer* printer) const;
   void GenerateAccessorDeclarations(io::Printer* printer) const;
-  void GenerateInlineAccessorDefinitions(io::Printer* printer) const;
+  void GenerateInlineAccessorDefinitions(io::Printer* printer,
+                                         bool is_inline) const;
   void GenerateClearingCode(io::Printer* printer) const;
   void GenerateMergingCode(io::Printer* printer) const;
   void GenerateSwappingCode(io::Printer* printer) const;
diff --git a/src/google/protobuf/compiler/cpp/cpp_message.cc b/src/google/protobuf/compiler/cpp/cpp_message.cc
index d0fd6c6d..bafa36f5 100644
--- a/src/google/protobuf/compiler/cpp/cpp_message.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_message.cc
@@ -87,8 +87,8 @@ const FieldDescriptor** SortFieldsByNumber(const Descriptor* descriptor) {
   for (int i = 0; i < descriptor->field_count(); i++) {
     fields[i] = descriptor->field(i);
   }
-  sort(fields, fields + descriptor->field_count(),
-       FieldOrderingByNumber());
+  std::sort(fields, fields + descriptor->field_count(),
+            FieldOrderingByNumber());
   return fields;
 }
 
@@ -253,7 +253,7 @@ void OptimizePadding(vector<const FieldDescriptor*>* fields) {
   // Sort by preferred location to keep fields as close to their original
   // location as possible.  Using stable_sort ensures that the output is
   // consistent across runs.
-  stable_sort(aligned_to_4.begin(), aligned_to_4.end());
+  std::stable_sort(aligned_to_4.begin(), aligned_to_4.end());
 
   // Now group fields aligned to 4 bytes (or the 4-field groups created above)
   // into pairs, and treat those like a single field aligned to 8 bytes.
@@ -269,7 +269,7 @@ void OptimizePadding(vector<const FieldDescriptor*>* fields) {
     aligned_to_8.push_back(field_group);
   }
   // Sort by preferred location.
-  stable_sort(aligned_to_8.begin(), aligned_to_8.end());
+  std::stable_sort(aligned_to_8.begin(), aligned_to_8.end());
 
   // Now pull out all the FieldDescriptors in order.
   fields->clear();
@@ -347,11 +347,11 @@ void CollectMapInfo(const Descriptor* descriptor,
     default:
       (*variables)["val"] = PrimitiveTypeName(val->cpp_type());
   }
-  (*variables)["key_type"] =
-      "::google::protobuf::FieldDescriptor::TYPE_" +
+  (*variables)["key_wire_type"] =
+      "::google::protobuf::internal::WireFormatLite::TYPE_" +
       ToUpper(DeclaredTypeMethodName(key->type()));
-  (*variables)["val_type"] =
-      "::google::protobuf::FieldDescriptor::TYPE_" +
+  (*variables)["val_wire_type"] =
+      "::google::protobuf::internal::WireFormatLite::TYPE_" +
       ToUpper(DeclaredTypeMethodName(val->type()));
 }
 
@@ -453,17 +453,17 @@ GenerateFieldAccessorDeclarations(io::Printer* printer) {
     vars["constant_name"] = FieldConstantName(field);
 
     if (field->is_repeated()) {
-      printer->Print(vars, "inline int $name$_size() const$deprecation$;\n");
+      printer->Print(vars, "int $name$_size() const$deprecation$;\n");
     } else if (HasHasMethod(field)) {
-      printer->Print(vars, "inline bool has_$name$() const$deprecation$;\n");
+      printer->Print(vars, "bool has_$name$() const$deprecation$;\n");
     } else if (HasPrivateHasMethod(field)) {
       printer->Print(vars,
           "private:\n"
-          "inline bool has_$name$() const$deprecation$;\n"
+          "bool has_$name$() const$deprecation$;\n"
           "public:\n");
     }
 
-    printer->Print(vars, "inline void clear_$name$()$deprecation$;\n");
+    printer->Print(vars, "void clear_$name$()$deprecation$;\n");
     printer->Print(vars, "static const int $constant_name$ = $number$;\n");
 
     // Generate type-specific accessor declarations.
@@ -482,7 +482,7 @@ GenerateFieldAccessorDeclarations(io::Printer* printer) {
 
   for (int i = 0; i < descriptor_->oneof_decl_count(); i++) {
     printer->Print(
-        "inline $camel_oneof_name$Case $oneof_name$_case() const;\n",
+        "$camel_oneof_name$Case $oneof_name$_case() const;\n",
         "camel_oneof_name",
         UnderscoresToCamelCase(descriptor_->oneof_decl(i)->name(), true),
         "oneof_name", descriptor_->oneof_decl(i)->name());
@@ -490,7 +490,7 @@ GenerateFieldAccessorDeclarations(io::Printer* printer) {
 }
 
 void MessageGenerator::
-GenerateFieldAccessorDefinitions(io::Printer* printer) {
+GenerateFieldAccessorDefinitions(io::Printer* printer, bool is_inline) {
   printer->Print("// $classname$\n\n", "classname", classname_);
 
   for (int i = 0; i < descriptor_->field_count(); i++) {
@@ -500,11 +500,12 @@ GenerateFieldAccessorDefinitions(io::Printer* printer) {
 
     map<string, string> vars;
     SetCommonFieldVariables(field, &vars, options_);
+    vars["inline"] = is_inline ? "inline" : "";
 
     // Generate has_$name$() or $name$_size().
     if (field->is_repeated()) {
       printer->Print(vars,
-        "inline int $classname$::$name$_size() const {\n"
+        "$inline$ int $classname$::$name$_size() const {\n"
         "  return $name$_.size();\n"
         "}\n");
     } else if (field->containing_oneof()) {
@@ -518,11 +519,11 @@ GenerateFieldAccessorDefinitions(io::Printer* printer) {
       vars["oneof_name"] = field->containing_oneof()->name();
       vars["oneof_index"] = SimpleItoa(field->containing_oneof()->index());
       printer->Print(vars,
-        "inline bool $classname$::has_$name$() const {\n"
+        "$inline$ bool $classname$::has_$name$() const {\n"
         "  return $oneof_name$_case() == k$field_name$;\n"
         "}\n");
       printer->Print(vars,
-        "inline void $classname$::set_has_$name$() {\n"
+        "$inline$ void $classname$::set_has_$name$() {\n"
         "  _oneof_case_[$oneof_index$] = k$field_name$;\n"
         "}\n");
     } else {
@@ -535,13 +536,13 @@ GenerateFieldAccessorDefinitions(io::Printer* printer) {
         vars["has_mask"] = FastHex32ToBuffer(1u << (field->index() % 32),
                                              buffer);
         printer->Print(vars,
-          "inline bool $classname$::has_$name$() const {\n"
+          "$inline$ bool $classname$::has_$name$() const {\n"
           "  return (_has_bits_[$has_array_index$] & 0x$has_mask$u) != 0;\n"
           "}\n"
-          "inline void $classname$::set_has_$name$() {\n"
+          "$inline$ void $classname$::set_has_$name$() {\n"
           "  _has_bits_[$has_array_index$] |= 0x$has_mask$u;\n"
           "}\n"
-          "inline void $classname$::clear_has_$name$() {\n"
+          "$inline$ void $classname$::clear_has_$name$() {\n"
           "  _has_bits_[$has_array_index$] &= ~0x$has_mask$u;\n"
           "}\n"
           );
@@ -551,12 +552,12 @@ GenerateFieldAccessorDefinitions(io::Printer* printer) {
           bool is_lazy = false;
           if (is_lazy) {
             printer->Print(vars,
-              "inline bool $classname$::has_$name$() const {\n"
+              "$inline$ bool $classname$::has_$name$() const {\n"
               "  return !$name$_.IsCleared();\n"
               "}\n");
           } else {
             printer->Print(vars,
-              "inline bool $classname$::has_$name$() const {\n"
+              "$inline$ bool $classname$::has_$name$() const {\n"
               "  return !_is_default_instance_ && $name$_ != NULL;\n"
               "}\n");
           }
@@ -566,7 +567,7 @@ GenerateFieldAccessorDefinitions(io::Printer* printer) {
 
     // Generate clear_$name$()
     printer->Print(vars,
-      "inline void $classname$::clear_$name$() {\n");
+      "$inline$ void $classname$::clear_$name$() {\n");
 
     printer->Indent();
 
@@ -595,7 +596,8 @@ GenerateFieldAccessorDefinitions(io::Printer* printer) {
     printer->Print("}\n");
 
     // Generate type-specific accessors.
-    field_generators_.get(field).GenerateInlineAccessorDefinitions(printer);
+    field_generators_.get(field).GenerateInlineAccessorDefinitions(printer,
+                                                                   is_inline);
 
     printer->Print("\n");
   }
@@ -608,12 +610,13 @@ GenerateFieldAccessorDefinitions(io::Printer* printer) {
     vars["cap_oneof_name"] =
         ToUpper(descriptor_->oneof_decl(i)->name());
     vars["classname"] = classname_;
+    vars["inline"] = is_inline ? "inline" : "";
     printer->Print(
       vars,
-      "inline bool $classname$::has_$oneof_name$() const {\n"
+      "$inline$ bool $classname$::has_$oneof_name$() const {\n"
       "  return $oneof_name$_case() != $cap_oneof_name$_NOT_SET;\n"
       "}\n"
-      "inline void $classname$::clear_has_$oneof_name$() {\n"
+      "$inline$ void $classname$::clear_has_$oneof_name$() {\n"
       "  _oneof_case_[$oneof_index$] = $cap_oneof_name$_NOT_SET;\n"
       "}\n");
   }
@@ -1169,18 +1172,18 @@ GenerateClassDefinition(io::Printer* printer) {
 }
 
 void MessageGenerator::
-GenerateInlineMethods(io::Printer* printer) {
+GenerateInlineMethods(io::Printer* printer, bool is_inline) {
   for (int i = 0; i < descriptor_->nested_type_count(); i++) {
     // map entry message doesn't need inline methods. Since map entry message
     // cannot be a top level class, we just need to avoid calling
     // GenerateInlineMethods here.
     if (IsMapEntryMessage(descriptor_->nested_type(i))) continue;
-    nested_generators_[i]->GenerateInlineMethods(printer);
+    nested_generators_[i]->GenerateInlineMethods(printer, is_inline);
     printer->Print(kThinSeparator);
     printer->Print("\n");
   }
 
-  GenerateFieldAccessorDefinitions(printer);
+  GenerateFieldAccessorDefinitions(printer, is_inline);
 
   // Generate oneof_case() functions.
   for (int i = 0; i < descriptor_->oneof_decl_count(); i++) {
@@ -1190,9 +1193,10 @@ GenerateInlineMethods(io::Printer* printer) {
         descriptor_->oneof_decl(i)->name(), true);
     vars["oneof_name"] = descriptor_->oneof_decl(i)->name();
     vars["oneof_index"] = SimpleItoa(descriptor_->oneof_decl(i)->index());
+    vars["inline"] = is_inline ? "inline " : "";
     printer->Print(
         vars,
-        "inline $class_name$::$camel_oneof_name$Case $class_name$::"
+        "$inline$$class_name$::$camel_oneof_name$Case $class_name$::"
         "$oneof_name$_case() const {\n"
         "  return $class_name$::$camel_oneof_name$Case("
         "_oneof_case_[$oneof_index$]);\n"
@@ -1222,7 +1226,9 @@ GenerateDescriptorDeclarations(io::Printer* printer) {
       for (int j = 0; j < descriptor_->oneof_decl(i)->field_count(); j++) {
         const FieldDescriptor* field = descriptor_->oneof_decl(i)->field(j);
         printer->Print("  ");
-        if (field->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE) {
+        if (field->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE ||
+            (field->cpp_type() == FieldDescriptor::CPPTYPE_STRING &&
+             EffectiveStringCType(field) != FieldOptions::STRING)) {
           printer->Print("const ");
         }
         field_generators_.get(field).GeneratePrivateMembers(printer);
@@ -1391,8 +1397,8 @@ GenerateTypeRegistrations(io::Printer* printer) {
       "      ::google::protobuf::internal::MapEntry<\n"
       "          $key$,\n"
       "          $val$,\n"
-      "          $key_type$,\n"
-      "          $val_type$,\n"
+      "          $key_wire_type$,\n"
+      "          $val_wire_type$,\n"
       "          $default_enum_value$>::CreateDefaultInstance(\n"
       "              $classname$_descriptor_));\n");
   }
@@ -2034,17 +2040,16 @@ GenerateClear(io::Printer* printer) {
 
   // Step 2a: Greedily seek runs of fields that can be cleared by memset-to-0.
   // The generated code uses two macros to help it clear runs of fields:
-  // OFFSET_OF_FIELD_ computes the offset (in bytes) of a field in the Message.
+  // ZR_HELPER_(f1) - ZR_HELPER_(f0) computes the difference, in bytes, of the
+  // positions of two fields in the Message.
   // ZR_ zeroes a non-empty range of fields via memset.
   const char* macros =
-      "#define OFFSET_OF_FIELD_(f) (reinterpret_cast<char*>(      \\\n"
-      "  &reinterpret_cast<$classname$*>(16)->f) - \\\n"
-      "   reinterpret_cast<char*>(16))\n\n"
-      "#define ZR_(first, last) do {                              \\\n"
-      "    size_t f = OFFSET_OF_FIELD_(first);                    \\\n"
-      "    size_t n = OFFSET_OF_FIELD_(last) - f + sizeof(last);  \\\n"
-      "    ::memset(&first, 0, n);                                \\\n"
-      "  } while (0)\n\n";
+      "#define ZR_HELPER_(f) reinterpret_cast<char*>(\\\n"
+      "  &reinterpret_cast<$classname$*>(16)->f)\n\n"
+      "#define ZR_(first, last) do {\\\n"
+      "  ::memset(&first, 0,\\\n"
+      "           ZR_HELPER_(last) - ZR_HELPER_(first) + sizeof(last));\\\n"
+      "} while (0)\n\n";
   for (int i = 0; i < runs_of_fields_.size(); i++) {
     const vector<string>& run = runs_of_fields_[i];
     if (run.size() < 2) continue;
@@ -2133,7 +2138,7 @@ GenerateClear(io::Printer* printer) {
   }
   if (macros_are_needed) {
     printer->Outdent();
-    printer->Print("\n#undef OFFSET_OF_FIELD_\n#undef ZR_\n\n");
+    printer->Print("\n#undef ZR_HELPER_\n#undef ZR_\n\n");
     printer->Indent();
   }
 
@@ -2919,8 +2924,8 @@ GenerateSerializeWithCachedSizesBody(io::Printer* printer, bool to_array) {
   for (int i = 0; i < descriptor_->extension_range_count(); ++i) {
     sorted_extensions.push_back(descriptor_->extension_range(i));
   }
-  sort(sorted_extensions.begin(), sorted_extensions.end(),
-       ExtensionRangeSorter());
+  std::sort(sorted_extensions.begin(), sorted_extensions.end(),
+            ExtensionRangeSorter());
 
   // Merge the fields and the extension ranges, both sorted by field number.
   int i, j;
diff --git a/src/google/protobuf/compiler/cpp/cpp_message.h b/src/google/protobuf/compiler/cpp/cpp_message.h
index dfbc9af5..ea96581d 100644
--- a/src/google/protobuf/compiler/cpp/cpp_message.h
+++ b/src/google/protobuf/compiler/cpp/cpp_message.h
@@ -82,7 +82,7 @@ class MessageGenerator {
 
   // Generate definitions of inline methods (placed at the end of the header
   // file).
-  void GenerateInlineMethods(io::Printer* printer);
+  void GenerateInlineMethods(io::Printer* printer, bool is_inline);
 
   // Source file stuff.
 
@@ -116,7 +116,7 @@ class MessageGenerator {
  private:
   // Generate declarations and definitions of accessors for fields.
   void GenerateFieldAccessorDeclarations(io::Printer* printer);
-  void GenerateFieldAccessorDefinitions(io::Printer* printer);
+  void GenerateFieldAccessorDefinitions(io::Printer* printer, bool is_inline);
 
   // Generate the field offsets array.
   void GenerateOffsets(io::Printer* printer);
diff --git a/src/google/protobuf/compiler/cpp/cpp_message_field.cc b/src/google/protobuf/compiler/cpp/cpp_message_field.cc
index b3cd0ba1..467b6bf6 100644
--- a/src/google/protobuf/compiler/cpp/cpp_message_field.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_message_field.cc
@@ -85,76 +85,141 @@ GeneratePrivateMembers(io::Printer* printer) const {
 
 void MessageFieldGenerator::
 GenerateAccessorDeclarations(io::Printer* printer) const {
+  if (SupportsArenas(descriptor_)) {
+    printer->Print(variables_,
+       "private:\n"
+       "void _slow_mutable_$name$()$deprecation$;\n");
+    if (SupportsArenas(descriptor_->message_type())) {
+      printer->Print(variables_,
+       "void _slow_set_allocated_$name$(\n"
+       "    ::google::protobuf::Arena* message_arena, $type$** $name$)$deprecation$;\n");
+    }
+    printer->Print(variables_,
+       "$type$* _slow_$release_name$()$deprecation$;\n"
+       "public:\n");
+  }
   printer->Print(variables_,
-    "inline const $type$& $name$() const$deprecation$;\n"
-    "inline $type$* mutable_$name$()$deprecation$;\n"
-    "inline $type$* $release_name$()$deprecation$;\n"
-    "inline void set_allocated_$name$($type$* $name$)$deprecation$;\n");
+    "const $type$& $name$() const$deprecation$;\n"
+    "$type$* mutable_$name$()$deprecation$;\n"
+    "$type$* $release_name$()$deprecation$;\n"
+    "void set_allocated_$name$($type$* $name$)$deprecation$;\n");
   if (SupportsArenas(descriptor_)) {
     printer->Print(variables_,
-      "inline $type$* unsafe_arena_release_$name$()$deprecation$;\n"
-      "inline void unsafe_arena_set_allocated_$name$(\n"
+      "$type$* unsafe_arena_release_$name$()$deprecation$;\n"
+      "void unsafe_arena_set_allocated_$name$(\n"
       "    $type$* $name$)$deprecation$;\n");
   }
 }
 
+void MessageFieldGenerator::GenerateNonInlineAccessorDefinitions(
+    io::Printer* printer) const {
+  if (SupportsArenas(descriptor_)) {
+    printer->Print(variables_,
+      "void $classname$::_slow_mutable_$name$() {\n");
+      if (SupportsArenas(descriptor_->message_type())) {
+        printer->Print(variables_,
+        "  $name$_ = ::google::protobuf::Arena::CreateMessage< $type$ >(\n"
+      "        GetArenaNoVirtual());\n");
+      } else {
+        printer->Print(variables_,
+         "  $name$_ = ::google::protobuf::Arena::Create< $type$ >(\n"
+         "     GetArenaNoVirtual());\n");
+      }
+    printer->Print(variables_,
+      "}\n"
+      "$type$* $classname$::_slow_$release_name$() {\n"
+      "  if ($name$_ == NULL) {\n"
+      "    return NULL;\n"
+      "  } else {\n"
+      "    $type$* temp = new $type$;\n"
+      "    temp->MergeFrom(*$name$_);\n"
+      "    $name$_ = NULL;\n"
+      "    return temp;\n"
+      "  }\n"
+      "}\n"
+      "$type$* $classname$::unsafe_arena_release_$name$() {\n"
+      "  $clear_hasbit$\n"
+      "  $type$* temp = $name$_;\n"
+      "  $name$_ = NULL;\n"
+      "  return temp;\n"
+      "}\n");
+    if (SupportsArenas(descriptor_->message_type())) {
+        printer->Print(variables_,
+          "void $classname$::_slow_set_allocated_$name$(\n"
+          "    ::google::protobuf::Arena* message_arena, $type$** $name$) {\n"
+          "    if (message_arena != NULL && \n"
+          "        ::google::protobuf::Arena::GetArena(*$name$) == NULL) {\n"
+          "      message_arena->Own(*$name$);\n"
+          "    } else if (message_arena !=\n"
+          "               ::google::protobuf::Arena::GetArena(*$name$)) {\n"
+          "      $type$* new_$name$ = \n"
+          "            ::google::protobuf::Arena::CreateMessage< $type$ >(\n"
+          "            message_arena);\n"
+          "      new_$name$->CopyFrom(**$name$);\n"
+          "      *$name$ = new_$name$;\n"
+          "    }\n"
+          "}\n");
+    }
+    printer->Print(variables_,
+      "void $classname$::unsafe_arena_set_allocated_$name$(\n"
+      "    $type$* $name$) {\n"
+      // If we're not on an arena, free whatever we were holding before.
+      // (If we are on arena, we can just forget the earlier pointer.)
+      "  if (GetArenaNoVirtual() == NULL) {\n"
+      "    delete $name$_;\n"
+      "  }\n"
+      "  $name$_ = $name$;\n"
+      "  if ($name$) {\n"
+      "    $set_hasbit$\n"
+      "  } else {\n"
+      "    $clear_hasbit$\n"
+      "  }\n"
+      "  // @@protoc_insertion_point(field_unsafe_arena_set_allocated"
+      ":$full_name$)\n"
+      "}\n");
+  }
+}
+
 void MessageFieldGenerator::
-GenerateInlineAccessorDefinitions(io::Printer* printer) const {
-  printer->Print(variables_,
-    "inline const $type$& $classname$::$name$() const {\n"
+GenerateInlineAccessorDefinitions(io::Printer* printer,
+                                  bool is_inline) const {
+  map<string, string> variables(variables_);
+  variables["inline"] = is_inline ? "inline" : "";
+  printer->Print(variables,
+    "$inline$ const $type$& $classname$::$name$() const {\n"
     "  // @@protoc_insertion_point(field_get:$full_name$)\n");
 
   PrintHandlingOptionalStaticInitializers(
-    variables_, descriptor_->file(), printer,
+    variables, descriptor_->file(), printer,
     // With static initializers.
     "  return $name$_ != NULL ? *$name$_ : *default_instance_->$name$_;\n",
     // Without.
     "  return $name$_ != NULL ? *$name$_ : *default_instance().$name$_;\n");
 
   if (SupportsArenas(descriptor_)) {
-    printer->Print(variables_,
+    printer->Print(variables,
       "}\n"
-      "inline $type$* $classname$::mutable_$name$() {\n"
+      "$inline$ $type$* $classname$::mutable_$name$() {\n"
       "  $set_hasbit$\n"
-      "  if ($name$_ == NULL) {\n");
-    if (SupportsArenas(descriptor_->message_type())) {
-      printer->Print(variables_,
-      "    $name$_ = ::google::protobuf::Arena::CreateMessage< $type$ >(\n"
-      "        GetArenaNoVirtual());\n");
-    } else {
-      printer->Print(variables_,
-       "    $name$_ = ::google::protobuf::Arena::Create< $type$ >(\n"
-       "        GetArenaNoVirtual());\n");
-    }
-    printer->Print(variables_, "  }\n"
+      "  if ($name$_ == NULL) {\n"
+      "    _slow_mutable_$name$();"
+      "  }\n"
       "  // @@protoc_insertion_point(field_mutable:$full_name$)\n"
       "  return $name$_;\n"
       "}\n"
-      "inline $type$* $classname$::$release_name$() {\n"
+      "$inline$ $type$* $classname$::$release_name$() {\n"
       "  $clear_hasbit$\n"
       "  if (GetArenaNoVirtual() != NULL) {\n"
-      "    if ($name$_ == NULL) {\n"
-      "      return NULL;\n"
-      "    } else {\n"
-      "      $type$* temp = new $type$;\n"
-      "      temp->MergeFrom(*$name$_);\n"
-      "      $name$_ = NULL;\n"
-      "      return temp;\n"
-      "    }\n"
+      "    return _slow_$release_name$();\n"
       "  } else {\n"
       "    $type$* temp = $name$_;\n"
       "    $name$_ = NULL;\n"
       "    return temp;\n"
       "  }\n"
       "}\n"
-      "inline $type$* $classname$::unsafe_arena_release_$name$() {\n"
-      "  $clear_hasbit$\n"
-      "  $type$* temp = $name$_;\n"
-      "  $name$_ = NULL;\n"
-      "  return temp;\n"
-      "}\n"
-      "inline void $classname$::set_allocated_$name$($type$* $name$) {\n"
-      "  if (GetArenaNoVirtual() == NULL) {\n"
+      "$inline$ void $classname$::set_allocated_$name$($type$* $name$) {\n"
+      "  ::google::protobuf::Arena* message_arena = GetArenaNoVirtual();\n"
+      "  if (message_arena == NULL) {\n"
       "    delete $name$_;\n"
       "  }\n"
       "  if ($name$ != NULL) {\n");
@@ -164,26 +229,15 @@ GenerateInlineAccessorDefinitions(io::Printer* printer) const {
       // so we might as well defer it. Otherwise, if incoming message is on a
       // different ownership domain (specific arena, or the heap) than we are,
       // copy to our arena (or heap, as the case may be).
-      printer->Print(variables_,
-        "    if (GetArenaNoVirtual() != NULL && \n"
-        "        ::google::protobuf::Arena::GetArena($name$) == NULL) {\n"
-        "      GetArenaNoVirtual()->Own($name$);\n"
-        "    } else if (GetArenaNoVirtual() !=\n"
-        "               ::google::protobuf::Arena::GetArena($name$)) {\n"
-        "      $type$* new_$name$ = \n"
-        "            ::google::protobuf::Arena::CreateMessage< $type$ >(\n"
-        "            GetArenaNoVirtual());\n"
-        "      new_$name$->CopyFrom(*$name$);\n"
-        "      $name$ = new_$name$;\n"
-        "    }\n");
+      printer->Print(variables,
+        "    _slow_set_allocated_$name$(message_arena, &$name$);\n");
     } else {
-      printer->Print(variables_,
-        "    if (GetArenaNoVirtual() != NULL) {\n"
-        "      GetArenaNoVirtual()->Own($name$);\n"
+      printer->Print(variables,
+        "    if (message_arena != NULL) {\n"
+        "      message_arena->Own($name$);\n"
         "    }\n");
     }
-
-    printer->Print(variables_,
+    printer->Print(variables,
       "  }\n"
       "  $name$_ = $name$;\n"
       "  if ($name$) {\n"
@@ -192,27 +246,11 @@ GenerateInlineAccessorDefinitions(io::Printer* printer) const {
       "    $clear_hasbit$\n"
       "  }\n"
       "  // @@protoc_insertion_point(field_set_allocated:$full_name$)\n"
-      "}\n"
-      "inline void $classname$::unsafe_arena_set_allocated_$name$(\n"
-      "    $type$* $name$) {\n"
-      // If we're not on an arena, free whatever we were holding before.
-      // (If we are on arena, we can just forget the earlier pointer.)
-      "  if (GetArenaNoVirtual() == NULL) {\n"
-      "    delete $name$_;\n"
-      "  }\n"
-      "  $name$_ = $name$;\n"
-      "  if ($name$) {\n"
-      "    $set_hasbit$\n"
-      "  } else {\n"
-      "    $clear_hasbit$\n"
-      "  }\n"
-      "  // @@protoc_insertion_point(field_unsafe_arena_set_allocated"
-      ":$full_name$)\n"
       "}\n");
   } else {
-    printer->Print(variables_,
+    printer->Print(variables,
       "}\n"
-      "inline $type$* $classname$::mutable_$name$() {\n"
+      "$inline$ $type$* $classname$::mutable_$name$() {\n"
       "  $set_hasbit$\n"
       "  if ($name$_ == NULL) {\n"
       "    $name$_ = new $type$;\n"
@@ -220,17 +258,17 @@ GenerateInlineAccessorDefinitions(io::Printer* printer) const {
       "  // @@protoc_insertion_point(field_mutable:$full_name$)\n"
       "  return $name$_;\n"
       "}\n"
-      "inline $type$* $classname$::$release_name$() {\n"
+      "$inline$ $type$* $classname$::$release_name$() {\n"
       "  $clear_hasbit$\n"
       "  $type$* temp = $name$_;\n"
       "  $name$_ = NULL;\n"
       "  return temp;\n"
       "}\n"
-      "inline void $classname$::set_allocated_$name$($type$* $name$) {\n"
+      "$inline$ void $classname$::set_allocated_$name$($type$* $name$) {\n"
       "  delete $name$_;\n");
 
     if (SupportsArenas(descriptor_->message_type())) {
-      printer->Print(variables_,
+      printer->Print(variables,
       "  if ($name$ != NULL && $name$->GetArena() != NULL) {\n"
       "    $type$* new_$name$ = new $type$;\n"
       "    new_$name$->CopyFrom(*$name$);\n"
@@ -238,7 +276,7 @@ GenerateInlineAccessorDefinitions(io::Printer* printer) const {
       "  }\n");
     }
 
-    printer->Print(variables_,
+    printer->Print(variables,
       "  $name$_ = $name$;\n"
       "  if ($name$) {\n"
       "    $set_hasbit$\n"
@@ -328,35 +366,38 @@ MessageOneofFieldGenerator(const FieldDescriptor* descriptor,
 MessageOneofFieldGenerator::~MessageOneofFieldGenerator() {}
 
 void MessageOneofFieldGenerator::
-GenerateInlineAccessorDefinitions(io::Printer* printer) const {
+GenerateInlineAccessorDefinitions(io::Printer* printer,
+                                  bool is_inline) const {
+  map<string, string> variables(variables_);
+  variables["inline"] = is_inline ? "inline" : "";
   if (SupportsArenas(descriptor_)) {
-    printer->Print(variables_,
-      "inline const $type$& $classname$::$name$() const {\n"
+    printer->Print(variables,
+      "$inline$ const $type$& $classname$::$name$() const {\n"
       "  // @@protoc_insertion_point(field_get:$full_name$)\n"
       "  return has_$name$() ? *$oneof_prefix$$name$_\n"
       "                      : $type$::default_instance();\n"
       "}\n"
-      "inline $type$* $classname$::mutable_$name$() {\n"
+      "$inline$ $type$* $classname$::mutable_$name$() {\n"
       "  if (!has_$name$()) {\n"
       "    clear_$oneof_name$();\n"
       "    set_has_$name$();\n");
     if (SupportsArenas(descriptor_->message_type())) {
-      printer->Print(variables_,
+      printer->Print(variables,
          "    $oneof_prefix$$name$_ = \n"
          "      ::google::protobuf::Arena::CreateMessage< $type$ >(\n"
          "      GetArenaNoVirtual());\n");
     } else {
-      printer->Print(variables_,
+      printer->Print(variables,
          "    $oneof_prefix$$name$_ = \n"
          "      ::google::protobuf::Arena::Create< $type$ >(\n"
          "      GetArenaNoVirtual());\n");
     }
-    printer->Print(variables_,
+    printer->Print(variables,
       "  }\n"
       "  // @@protoc_insertion_point(field_mutable:$full_name$)\n"
       "  return $oneof_prefix$$name$_;\n"
       "}\n"
-      "inline $type$* $classname$::$release_name$() {\n"
+      "$inline$ $type$* $classname$::$release_name$() {\n"
       "  if (has_$name$()) {\n"
       "    clear_has_$oneof_name$();\n"
       "    if (GetArenaNoVirtual() != NULL) {\n"
@@ -375,7 +416,7 @@ GenerateInlineAccessorDefinitions(io::Printer* printer) const {
       "    return NULL;\n"
       "  }\n"
       "}\n"
-      "inline $type$* $classname$::unsafe_arena_release_$name$() {\n"
+      "$inline$ $type$* $classname$::unsafe_arena_release_$name$() {\n"
       "  if (has_$name$()) {\n"
       "    clear_has_$oneof_name$();\n"
       "    $type$* temp = $oneof_prefix$$name$_;\n"
@@ -385,12 +426,12 @@ GenerateInlineAccessorDefinitions(io::Printer* printer) const {
       "    return NULL;\n"
       "  }\n"
       "}\n"
-      "inline void $classname$::set_allocated_$name$($type$* $name$) {\n"
+      "$inline$ void $classname$::set_allocated_$name$($type$* $name$) {\n"
       "  clear_$oneof_name$();\n"
       "  if ($name$) {\n");
 
     if (SupportsArenas(descriptor_->message_type())) {
-      printer->Print(variables_,
+      printer->Print(variables,
         // If incoming message is on the heap and we are on an arena, just Own()
         // it (see above). If it's on a different arena than we are or one of us
         // is on the heap, we make a copy to our arena/heap.
@@ -406,19 +447,19 @@ GenerateInlineAccessorDefinitions(io::Printer* printer) const {
         "      $name$ = new_$name$;\n"
         "    }\n");
     } else {
-      printer->Print(variables_,
+      printer->Print(variables,
         "    if (GetArenaNoVirtual() != NULL) {\n"
         "      GetArenaNoVirtual()->Own($name$);\n"
         "    }\n");
     }
 
-    printer->Print(variables_,
+    printer->Print(variables,
       "    set_has_$name$();\n"
       "    $oneof_prefix$$name$_ = $name$;\n"
       "  }\n"
       "  // @@protoc_insertion_point(field_set_allocated:$full_name$)\n"
       "}\n"
-      "inline void $classname$::unsafe_arena_set_allocated_$name$("
+      "$inline$ void $classname$::unsafe_arena_set_allocated_$name$("
       "$type$* $name$) {\n"
       // We rely on the oneof clear method to free the earlier contents of this
       // oneof. We can directly use the pointer we're given to set the new
@@ -432,13 +473,13 @@ GenerateInlineAccessorDefinitions(io::Printer* printer) const {
       "$full_name$)\n"
       "}\n");
   } else {
-    printer->Print(variables_,
-      "inline const $type$& $classname$::$name$() const {\n"
+    printer->Print(variables,
+      "$inline$ const $type$& $classname$::$name$() const {\n"
       "  // @@protoc_insertion_point(field_get:$full_name$)\n"
       "  return has_$name$() ? *$oneof_prefix$$name$_\n"
       "                      : $type$::default_instance();\n"
       "}\n"
-      "inline $type$* $classname$::mutable_$name$() {\n"
+      "$inline$ $type$* $classname$::mutable_$name$() {\n"
       "  if (!has_$name$()) {\n"
       "    clear_$oneof_name$();\n"
       "    set_has_$name$();\n"
@@ -447,7 +488,7 @@ GenerateInlineAccessorDefinitions(io::Printer* printer) const {
       "  // @@protoc_insertion_point(field_mutable:$full_name$)\n"
       "  return $oneof_prefix$$name$_;\n"
       "}\n"
-      "inline $type$* $classname$::$release_name$() {\n"
+      "$inline$ $type$* $classname$::$release_name$() {\n"
       "  if (has_$name$()) {\n"
       "    clear_has_$oneof_name$();\n"
       "    $type$* temp = $oneof_prefix$$name$_;\n"
@@ -457,18 +498,18 @@ GenerateInlineAccessorDefinitions(io::Printer* printer) const {
       "    return NULL;\n"
       "  }\n"
       "}\n"
-      "inline void $classname$::set_allocated_$name$($type$* $name$) {\n"
+      "$inline$ void $classname$::set_allocated_$name$($type$* $name$) {\n"
       "  clear_$oneof_name$();\n"
       "  if ($name$) {\n");
     if (SupportsArenas(descriptor_->message_type())) {
-      printer->Print(variables_,
+      printer->Print(variables,
         "    if ($name$->GetArena() != NULL) {\n"
         "      $type$* new_$name$ = new $type$;\n"
         "      new_$name$->CopyFrom(*$name$);\n"
         "      $name$ = new_$name$;\n"
         "    }\n");
     }
-    printer->Print(variables_,
+    printer->Print(variables,
       "    set_has_$name$();\n"
       "    $oneof_prefix$$name$_ = $name$;\n"
       "  }\n"
@@ -521,38 +562,41 @@ GeneratePrivateMembers(io::Printer* printer) const {
 void RepeatedMessageFieldGenerator::
 GenerateAccessorDeclarations(io::Printer* printer) const {
   printer->Print(variables_,
-    "inline const $type$& $name$(int index) const$deprecation$;\n"
-    "inline $type$* mutable_$name$(int index)$deprecation$;\n"
-    "inline $type$* add_$name$()$deprecation$;\n");
+    "const $type$& $name$(int index) const$deprecation$;\n"
+    "$type$* mutable_$name$(int index)$deprecation$;\n"
+    "$type$* add_$name$()$deprecation$;\n");
   printer->Print(variables_,
-    "inline const ::google::protobuf::RepeatedPtrField< $type$ >&\n"
+    "const ::google::protobuf::RepeatedPtrField< $type$ >&\n"
     "    $name$() const$deprecation$;\n"
-    "inline ::google::protobuf::RepeatedPtrField< $type$ >*\n"
+    "::google::protobuf::RepeatedPtrField< $type$ >*\n"
     "    mutable_$name$()$deprecation$;\n");
 }
 
 void RepeatedMessageFieldGenerator::
-GenerateInlineAccessorDefinitions(io::Printer* printer) const {
-  printer->Print(variables_,
-    "inline const $type$& $classname$::$name$(int index) const {\n"
+GenerateInlineAccessorDefinitions(io::Printer* printer,
+                                  bool is_inline) const {
+  map<string, string> variables(variables_);
+  variables["inline"] = is_inline ? "inline" : "";
+  printer->Print(variables,
+    "$inline$ const $type$& $classname$::$name$(int index) const {\n"
     "  // @@protoc_insertion_point(field_get:$full_name$)\n"
     "  return $name$_.$cppget$(index);\n"
     "}\n"
-    "inline $type$* $classname$::mutable_$name$(int index) {\n"
+    "$inline$ $type$* $classname$::mutable_$name$(int index) {\n"
     "  // @@protoc_insertion_point(field_mutable:$full_name$)\n"
     "  return $name$_.Mutable(index);\n"
     "}\n"
-    "inline $type$* $classname$::add_$name$() {\n"
+    "$inline$ $type$* $classname$::add_$name$() {\n"
     "  // @@protoc_insertion_point(field_add:$full_name$)\n"
     "  return $name$_.Add();\n"
     "}\n");
-  printer->Print(variables_,
-    "inline const ::google::protobuf::RepeatedPtrField< $type$ >&\n"
+  printer->Print(variables,
+    "$inline$ const ::google::protobuf::RepeatedPtrField< $type$ >&\n"
     "$classname$::$name$() const {\n"
     "  // @@protoc_insertion_point(field_list:$full_name$)\n"
     "  return $name$_;\n"
     "}\n"
-    "inline ::google::protobuf::RepeatedPtrField< $type$ >*\n"
+    "$inline$ ::google::protobuf::RepeatedPtrField< $type$ >*\n"
     "$classname$::mutable_$name$() {\n"
     "  // @@protoc_insertion_point(field_mutable_list:$full_name$)\n"
     "  return &$name$_;\n"
diff --git a/src/google/protobuf/compiler/cpp/cpp_message_field.h b/src/google/protobuf/compiler/cpp/cpp_message_field.h
index 2dff3144..c1704fc1 100644
--- a/src/google/protobuf/compiler/cpp/cpp_message_field.h
+++ b/src/google/protobuf/compiler/cpp/cpp_message_field.h
@@ -53,7 +53,9 @@ class MessageFieldGenerator : public FieldGenerator {
   // implements FieldGenerator ---------------------------------------
   void GeneratePrivateMembers(io::Printer* printer) const;
   void GenerateAccessorDeclarations(io::Printer* printer) const;
-  void GenerateInlineAccessorDefinitions(io::Printer* printer) const;
+  void GenerateInlineAccessorDefinitions(io::Printer* printer,
+                                         bool is_inline) const;
+  void GenerateNonInlineAccessorDefinitions(io::Printer* printer) const;
   void GenerateClearingCode(io::Printer* printer) const;
   void GenerateMergingCode(io::Printer* printer) const;
   void GenerateSwappingCode(io::Printer* printer) const;
@@ -78,7 +80,9 @@ class MessageOneofFieldGenerator : public MessageFieldGenerator {
   ~MessageOneofFieldGenerator();
 
   // implements FieldGenerator ---------------------------------------
-  void GenerateInlineAccessorDefinitions(io::Printer* printer) const;
+  void GenerateInlineAccessorDefinitions(io::Printer* printer,
+                                         bool is_inline) const;
+  void GenerateNonInlineAccessorDefinitions(io::Printer* printer) const {}
   void GenerateClearingCode(io::Printer* printer) const;
   void GenerateSwappingCode(io::Printer* printer) const;
   void GenerateConstructorCode(io::Printer* printer) const;
@@ -96,7 +100,8 @@ class RepeatedMessageFieldGenerator : public FieldGenerator {
   // implements FieldGenerator ---------------------------------------
   void GeneratePrivateMembers(io::Printer* printer) const;
   void GenerateAccessorDeclarations(io::Printer* printer) const;
-  void GenerateInlineAccessorDefinitions(io::Printer* printer) const;
+  void GenerateInlineAccessorDefinitions(io::Printer* printer,
+                                         bool is_inline) const;
   void GenerateClearingCode(io::Printer* printer) const;
   void GenerateMergingCode(io::Printer* printer) const;
   void GenerateSwappingCode(io::Printer* printer) const;
diff --git a/src/google/protobuf/compiler/cpp/cpp_primitive_field.cc b/src/google/protobuf/compiler/cpp/cpp_primitive_field.cc
index 9a2c930e..329eae32 100644
--- a/src/google/protobuf/compiler/cpp/cpp_primitive_field.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_primitive_field.cc
@@ -117,18 +117,20 @@ GeneratePrivateMembers(io::Printer* printer) const {
 void PrimitiveFieldGenerator::
 GenerateAccessorDeclarations(io::Printer* printer) const {
   printer->Print(variables_,
-    "inline $type$ $name$() const$deprecation$;\n"
-    "inline void set_$name$($type$ value)$deprecation$;\n");
+    "$type$ $name$() const$deprecation$;\n"
+    "void set_$name$($type$ value)$deprecation$;\n");
 }
 
 void PrimitiveFieldGenerator::
-GenerateInlineAccessorDefinitions(io::Printer* printer) const {
-  printer->Print(variables_,
-    "inline $type$ $classname$::$name$() const {\n"
+GenerateInlineAccessorDefinitions(io::Printer* printer, bool is_inline) const {
+  map<string, string> variables(variables_);
+  variables["inline"] = is_inline ? "inline" : "";
+  printer->Print(variables,
+    "$inline$ $type$ $classname$::$name$() const {\n"
     "  // @@protoc_insertion_point(field_get:$full_name$)\n"
     "  return $name$_;\n"
     "}\n"
-    "inline void $classname$::set_$name$($type$ value) {\n"
+    "$inline$ void $classname$::set_$name$($type$ value) {\n"
     "  $set_hasbit$\n"
     "  $name$_ = value;\n"
     "  // @@protoc_insertion_point(field_set:$full_name$)\n"
@@ -204,16 +206,18 @@ PrimitiveOneofFieldGenerator(const FieldDescriptor* descriptor,
 PrimitiveOneofFieldGenerator::~PrimitiveOneofFieldGenerator() {}
 
 void PrimitiveOneofFieldGenerator::
-GenerateInlineAccessorDefinitions(io::Printer* printer) const {
-  printer->Print(variables_,
-    "inline $type$ $classname$::$name$() const {\n"
+GenerateInlineAccessorDefinitions(io::Printer* printer, bool is_inline) const {
+  map<string, string> variables(variables_);
+  variables["inline"] = is_inline ? "inline" : "";
+  printer->Print(variables,
+    "$inline$ $type$ $classname$::$name$() const {\n"
     "  // @@protoc_insertion_point(field_get:$full_name$)\n"
     "  if (has_$name$()) {\n"
     "    return $oneof_prefix$$name$_;\n"
     "  }\n"
     "  return $default$;\n"
     "}\n"
-    "inline void $classname$::set_$name$($type$ value) {\n"
+    "$inline$ void $classname$::set_$name$($type$ value) {\n"
     "  if (!has_$name$()) {\n"
     "    clear_$oneof_name$();\n"
     "    set_has_$name$();\n"
@@ -282,38 +286,40 @@ GeneratePrivateMembers(io::Printer* printer) const {
 void RepeatedPrimitiveFieldGenerator::
 GenerateAccessorDeclarations(io::Printer* printer) const {
   printer->Print(variables_,
-    "inline $type$ $name$(int index) const$deprecation$;\n"
-    "inline void set_$name$(int index, $type$ value)$deprecation$;\n"
-    "inline void add_$name$($type$ value)$deprecation$;\n");
+    "$type$ $name$(int index) const$deprecation$;\n"
+    "void set_$name$(int index, $type$ value)$deprecation$;\n"
+    "void add_$name$($type$ value)$deprecation$;\n");
   printer->Print(variables_,
-    "inline const ::google::protobuf::RepeatedField< $type$ >&\n"
+    "const ::google::protobuf::RepeatedField< $type$ >&\n"
     "    $name$() const$deprecation$;\n"
-    "inline ::google::protobuf::RepeatedField< $type$ >*\n"
+    "::google::protobuf::RepeatedField< $type$ >*\n"
     "    mutable_$name$()$deprecation$;\n");
 }
 
 void RepeatedPrimitiveFieldGenerator::
-GenerateInlineAccessorDefinitions(io::Printer* printer) const {
-  printer->Print(variables_,
-    "inline $type$ $classname$::$name$(int index) const {\n"
+GenerateInlineAccessorDefinitions(io::Printer* printer, bool is_inline) const {
+  map<string, string> variables(variables_);
+  variables["inline"] = is_inline ? "inline" : "";
+  printer->Print(variables,
+    "$inline$ $type$ $classname$::$name$(int index) const {\n"
     "  // @@protoc_insertion_point(field_get:$full_name$)\n"
     "  return $name$_.Get(index);\n"
     "}\n"
-    "inline void $classname$::set_$name$(int index, $type$ value) {\n"
+    "$inline$ void $classname$::set_$name$(int index, $type$ value) {\n"
     "  $name$_.Set(index, value);\n"
     "  // @@protoc_insertion_point(field_set:$full_name$)\n"
     "}\n"
-    "inline void $classname$::add_$name$($type$ value) {\n"
+    "$inline$ void $classname$::add_$name$($type$ value) {\n"
     "  $name$_.Add(value);\n"
     "  // @@protoc_insertion_point(field_add:$full_name$)\n"
     "}\n");
-  printer->Print(variables_,
-    "inline const ::google::protobuf::RepeatedField< $type$ >&\n"
+  printer->Print(variables,
+    "$inline$ const ::google::protobuf::RepeatedField< $type$ >&\n"
     "$classname$::$name$() const {\n"
     "  // @@protoc_insertion_point(field_list:$full_name$)\n"
     "  return $name$_;\n"
     "}\n"
-    "inline ::google::protobuf::RepeatedField< $type$ >*\n"
+    "$inline$ ::google::protobuf::RepeatedField< $type$ >*\n"
     "$classname$::mutable_$name$() {\n"
     "  // @@protoc_insertion_point(field_mutable_list:$full_name$)\n"
     "  return &$name$_;\n"
diff --git a/src/google/protobuf/compiler/cpp/cpp_primitive_field.h b/src/google/protobuf/compiler/cpp/cpp_primitive_field.h
index 97b5e867..fcd7d684 100644
--- a/src/google/protobuf/compiler/cpp/cpp_primitive_field.h
+++ b/src/google/protobuf/compiler/cpp/cpp_primitive_field.h
@@ -53,7 +53,8 @@ class PrimitiveFieldGenerator : public FieldGenerator {
   // implements FieldGenerator ---------------------------------------
   void GeneratePrivateMembers(io::Printer* printer) const;
   void GenerateAccessorDeclarations(io::Printer* printer) const;
-  void GenerateInlineAccessorDefinitions(io::Printer* printer) const;
+  void GenerateInlineAccessorDefinitions(io::Printer* printer,
+                                         bool is_inline) const;
   void GenerateClearingCode(io::Printer* printer) const;
   void GenerateMergingCode(io::Printer* printer) const;
   void GenerateSwappingCode(io::Printer* printer) const;
@@ -78,7 +79,8 @@ class PrimitiveOneofFieldGenerator : public PrimitiveFieldGenerator {
   ~PrimitiveOneofFieldGenerator();
 
   // implements FieldGenerator ---------------------------------------
-  void GenerateInlineAccessorDefinitions(io::Printer* printer) const;
+  void GenerateInlineAccessorDefinitions(io::Printer* printer,
+                                         bool is_inline) const;
   void GenerateClearingCode(io::Printer* printer) const;
   void GenerateSwappingCode(io::Printer* printer) const;
   void GenerateConstructorCode(io::Printer* printer) const;
@@ -97,7 +99,8 @@ class RepeatedPrimitiveFieldGenerator : public FieldGenerator {
   // implements FieldGenerator ---------------------------------------
   void GeneratePrivateMembers(io::Printer* printer) const;
   void GenerateAccessorDeclarations(io::Printer* printer) const;
-  void GenerateInlineAccessorDefinitions(io::Printer* printer) const;
+  void GenerateInlineAccessorDefinitions(io::Printer* printer,
+                                         bool is_inline) const;
   void GenerateClearingCode(io::Printer* printer) const;
   void GenerateMergingCode(io::Printer* printer) const;
   void GenerateSwappingCode(io::Printer* printer) const;
diff --git a/src/google/protobuf/compiler/cpp/cpp_string_field.cc b/src/google/protobuf/compiler/cpp/cpp_string_field.cc
index 04ed08c9..1a1bcd3d 100644
--- a/src/google/protobuf/compiler/cpp/cpp_string_field.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_string_field.cc
@@ -127,7 +127,11 @@ GenerateAccessorDeclarations(io::Printer* printer) const {
   // files that applied the ctype.  The field can still be accessed via the
   // reflection interface since the reflection interface is independent of
   // the string's underlying representation.
-  if (descriptor_->options().ctype() != FieldOptions::STRING) {
+
+  bool unknown_ctype =
+      descriptor_->options().ctype() != EffectiveStringCType(descriptor_);
+
+  if (unknown_ctype) {
     printer->Outdent();
     printer->Print(
       " private:\n"
@@ -136,23 +140,23 @@ GenerateAccessorDeclarations(io::Printer* printer) const {
   }
 
   printer->Print(variables_,
-    "inline const ::std::string& $name$() const$deprecation$;\n"
-    "inline void set_$name$(const ::std::string& value)$deprecation$;\n"
-    "inline void set_$name$(const char* value)$deprecation$;\n"
-    "inline void set_$name$(const $pointer_type$* value, size_t size)"
+    "const ::std::string& $name$() const$deprecation$;\n"
+    "void set_$name$(const ::std::string& value)$deprecation$;\n"
+    "void set_$name$(const char* value)$deprecation$;\n"
+    "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 void set_allocated_$name$(::std::string* $name$)$deprecation$;\n");
+    "::std::string* mutable_$name$()$deprecation$;\n"
+    "::std::string* $release_name$()$deprecation$;\n"
+    "void set_allocated_$name$(::std::string* $name$)$deprecation$;\n");
   if (SupportsArenas(descriptor_)) {
     printer->Print(variables_,
-      "inline ::std::string* unsafe_arena_release_$name$()$deprecation$;\n"
-      "inline void unsafe_arena_set_allocated_$name$(\n"
+      "::std::string* unsafe_arena_release_$name$()$deprecation$;\n"
+      "void unsafe_arena_set_allocated_$name$(\n"
       "    ::std::string* $name$)$deprecation$;\n");
   }
 
 
-  if (descriptor_->options().ctype() != FieldOptions::STRING) {
+  if (unknown_ctype) {
     printer->Outdent();
     printer->Print(" public:\n");
     printer->Indent();
@@ -160,25 +164,28 @@ GenerateAccessorDeclarations(io::Printer* printer) const {
 }
 
 void StringFieldGenerator::
-GenerateInlineAccessorDefinitions(io::Printer* printer) const {
+GenerateInlineAccessorDefinitions(io::Printer* printer,
+                                  bool is_inline) const {
+  map<string, string> variables(variables_);
+  variables["inline"] = is_inline ? "inline" : "";
   if (SupportsArenas(descriptor_)) {
-    printer->Print(variables_,
-      "inline const ::std::string& $classname$::$name$() const {\n"
+    printer->Print(variables,
+      "$inline$ const ::std::string& $classname$::$name$() const {\n"
       "  // @@protoc_insertion_point(field_get:$full_name$)\n"
       "  return $name$_.Get($default_variable$);\n"
       "}\n"
-      "inline void $classname$::set_$name$(const ::std::string& value) {\n"
+      "$inline$ void $classname$::set_$name$(const ::std::string& value) {\n"
       "  $set_hasbit$\n"
       "  $name$_.Set($default_variable$, value, GetArenaNoVirtual());\n"
       "  // @@protoc_insertion_point(field_set:$full_name$)\n"
       "}\n"
-      "inline void $classname$::set_$name$(const char* value) {\n"
+      "$inline$ void $classname$::set_$name$(const char* value) {\n"
       "  $set_hasbit$\n"
       "  $name$_.Set($default_variable$, $string_piece$(value),\n"
       "              GetArenaNoVirtual());\n"
       "  // @@protoc_insertion_point(field_set_char:$full_name$)\n"
       "}\n"
-      "inline "
+      "$inline$ "
       "void $classname$::set_$name$(const $pointer_type$* value,\n"
       "    size_t size) {\n"
       "  $set_hasbit$\n"
@@ -186,22 +193,22 @@ GenerateInlineAccessorDefinitions(io::Printer* printer) const {
       "      reinterpret_cast<const char*>(value), size), GetArenaNoVirtual());\n"
       "  // @@protoc_insertion_point(field_set_pointer:$full_name$)\n"
       "}\n"
-      "inline ::std::string* $classname$::mutable_$name$() {\n"
+      "$inline$ ::std::string* $classname$::mutable_$name$() {\n"
       "  $set_hasbit$\n"
       "  // @@protoc_insertion_point(field_mutable:$full_name$)\n"
       "  return $name$_.Mutable($default_variable$, GetArenaNoVirtual());\n"
       "}\n"
-      "inline ::std::string* $classname$::$release_name$() {\n"
+      "$inline$ ::std::string* $classname$::$release_name$() {\n"
       "  $clear_hasbit$\n"
       "  return $name$_.Release($default_variable$, GetArenaNoVirtual());\n"
       "}\n"
-      "inline ::std::string* $classname$::unsafe_arena_release_$name$() {\n"
+      "$inline$ ::std::string* $classname$::unsafe_arena_release_$name$() {\n"
       "  GOOGLE_DCHECK(GetArenaNoVirtual() != NULL);\n"
       "  $clear_hasbit$\n"
       "  return $name$_.UnsafeArenaRelease($default_variable$,\n"
       "      GetArenaNoVirtual());\n"
       "}\n"
-      "inline void $classname$::set_allocated_$name$(::std::string* $name$) {\n"
+      "$inline$ void $classname$::set_allocated_$name$(::std::string* $name$) {\n"
       "  if ($name$ != NULL) {\n"
       "    $set_hasbit$\n"
       "  } else {\n"
@@ -211,7 +218,7 @@ GenerateInlineAccessorDefinitions(io::Printer* printer) const {
       "      GetArenaNoVirtual());\n"
       "  // @@protoc_insertion_point(field_set_allocated:$full_name$)\n"
       "}\n"
-      "inline void $classname$::unsafe_arena_set_allocated_$name$(\n"
+      "$inline$ void $classname$::unsafe_arena_set_allocated_$name$(\n"
       "    ::std::string* $name$) {\n"
       "  GOOGLE_DCHECK(GetArenaNoVirtual() != NULL);\n"
       "  if ($name$ != NULL) {\n"
@@ -226,22 +233,22 @@ GenerateInlineAccessorDefinitions(io::Printer* printer) const {
       "}\n");
   } else {
     // No-arena case.
-    printer->Print(variables_,
-      "inline const ::std::string& $classname$::$name$() const {\n"
+    printer->Print(variables,
+      "$inline$ const ::std::string& $classname$::$name$() const {\n"
       "  // @@protoc_insertion_point(field_get:$full_name$)\n"
       "  return $name$_.GetNoArena($default_variable$);\n"
       "}\n"
-      "inline void $classname$::set_$name$(const ::std::string& value) {\n"
+      "$inline$ void $classname$::set_$name$(const ::std::string& value) {\n"
       "  $set_hasbit$\n"
       "  $name$_.SetNoArena($default_variable$, value);\n"
       "  // @@protoc_insertion_point(field_set:$full_name$)\n"
       "}\n"
-      "inline void $classname$::set_$name$(const char* value) {\n"
+      "$inline$ void $classname$::set_$name$(const char* value) {\n"
       "  $set_hasbit$\n"
       "  $name$_.SetNoArena($default_variable$, $string_piece$(value));\n"
       "  // @@protoc_insertion_point(field_set_char:$full_name$)\n"
       "}\n"
-      "inline "
+      "$inline$ "
       "void $classname$::set_$name$(const $pointer_type$* value, "
       "size_t size) {\n"
       "  $set_hasbit$\n"
@@ -249,16 +256,16 @@ GenerateInlineAccessorDefinitions(io::Printer* printer) const {
       "      $string_piece$(reinterpret_cast<const char*>(value), size));\n"
       "  // @@protoc_insertion_point(field_set_pointer:$full_name$)\n"
       "}\n"
-      "inline ::std::string* $classname$::mutable_$name$() {\n"
+      "$inline$ ::std::string* $classname$::mutable_$name$() {\n"
       "  $set_hasbit$\n"
       "  // @@protoc_insertion_point(field_mutable:$full_name$)\n"
       "  return $name$_.MutableNoArena($default_variable$);\n"
       "}\n"
-      "inline ::std::string* $classname$::$release_name$() {\n"
+      "$inline$ ::std::string* $classname$::$release_name$() {\n"
       "  $clear_hasbit$\n"
       "  return $name$_.ReleaseNoArena($default_variable$);\n"
       "}\n"
-      "inline void $classname$::set_allocated_$name$(::std::string* $name$) {\n"
+      "$inline$ void $classname$::set_allocated_$name$(::std::string* $name$) {\n"
       "  if ($name$ != NULL) {\n"
       "    $set_hasbit$\n"
       "  } else {\n"
@@ -422,17 +429,20 @@ StringOneofFieldGenerator(const FieldDescriptor* descriptor,
 StringOneofFieldGenerator::~StringOneofFieldGenerator() {}
 
 void StringOneofFieldGenerator::
-GenerateInlineAccessorDefinitions(io::Printer* printer) const {
+GenerateInlineAccessorDefinitions(io::Printer* printer,
+                                  bool is_inline) const {
+  map<string, string> variables(variables_);
+  variables["inline"] = is_inline ? "inline" : "";
   if (SupportsArenas(descriptor_)) {
-    printer->Print(variables_,
-      "inline const ::std::string& $classname$::$name$() const {\n"
+    printer->Print(variables,
+      "$inline$ const ::std::string& $classname$::$name$() const {\n"
       "  // @@protoc_insertion_point(field_get:$full_name$)\n"
       "  if (has_$name$()) {\n"
       "    return $oneof_prefix$$name$_.Get($default_variable$);\n"
       "  }\n"
       "  return *$default_variable$;\n"
       "}\n"
-      "inline void $classname$::set_$name$(const ::std::string& value) {\n"
+      "$inline$ void $classname$::set_$name$(const ::std::string& value) {\n"
       "  if (!has_$name$()) {\n"
       "    clear_$oneof_name$();\n"
       "    set_has_$name$();\n"
@@ -442,7 +452,7 @@ GenerateInlineAccessorDefinitions(io::Printer* printer) const {
       "      GetArenaNoVirtual());\n"
       "  // @@protoc_insertion_point(field_set:$full_name$)\n"
       "}\n"
-      "inline void $classname$::set_$name$(const char* value) {\n"
+      "$inline$ void $classname$::set_$name$(const char* value) {\n"
       "  if (!has_$name$()) {\n"
       "    clear_$oneof_name$();\n"
       "    set_has_$name$();\n"
@@ -452,7 +462,7 @@ GenerateInlineAccessorDefinitions(io::Printer* printer) const {
       "      $string_piece$(value), GetArenaNoVirtual());\n"
       "  // @@protoc_insertion_point(field_set_char:$full_name$)\n"
       "}\n"
-      "inline "
+      "$inline$ "
       "void $classname$::set_$name$(const $pointer_type$* value,\n"
       "                             size_t size) {\n"
       "  if (!has_$name$()) {\n"
@@ -465,7 +475,7 @@ GenerateInlineAccessorDefinitions(io::Printer* printer) const {
       "      GetArenaNoVirtual());\n"
       "  // @@protoc_insertion_point(field_set_pointer:$full_name$)\n"
       "}\n"
-      "inline ::std::string* $classname$::mutable_$name$() {\n"
+      "$inline$ ::std::string* $classname$::mutable_$name$() {\n"
       "  if (!has_$name$()) {\n"
       "    clear_$oneof_name$();\n"
       "    set_has_$name$();\n"
@@ -475,7 +485,7 @@ GenerateInlineAccessorDefinitions(io::Printer* printer) const {
       "      GetArenaNoVirtual());\n"
       "  // @@protoc_insertion_point(field_mutable:$full_name$)\n"
       "}\n"
-      "inline ::std::string* $classname$::$release_name$() {\n"
+      "$inline$ ::std::string* $classname$::$release_name$() {\n"
       "  if (has_$name$()) {\n"
       "    clear_has_$oneof_name$();\n"
       "    return $oneof_prefix$$name$_.Release($default_variable$,\n"
@@ -484,7 +494,7 @@ GenerateInlineAccessorDefinitions(io::Printer* printer) const {
       "    return NULL;\n"
       "  }\n"
       "}\n"
-      "inline ::std::string* $classname$::unsafe_arena_release_$name$() {\n"
+      "$inline$ ::std::string* $classname$::unsafe_arena_release_$name$() {\n"
       "  GOOGLE_DCHECK(GetArenaNoVirtual() != NULL);\n"
       "  if (has_$name$()) {\n"
       "    clear_has_$oneof_name$();\n"
@@ -494,7 +504,7 @@ GenerateInlineAccessorDefinitions(io::Printer* printer) const {
       "    return NULL;\n"
       "  }\n"
       "}\n"
-      "inline void $classname$::set_allocated_$name$(::std::string* $name$) {\n"
+      "$inline$ void $classname$::set_allocated_$name$(::std::string* $name$) {\n"
       "  if (!has_$name$()) {\n"
       "    $oneof_prefix$$name$_.UnsafeSetDefault($default_variable$);\n"
       "  }\n"
@@ -506,7 +516,7 @@ GenerateInlineAccessorDefinitions(io::Printer* printer) const {
       "  }\n"
       "  // @@protoc_insertion_point(field_set_allocated:$full_name$)\n"
       "}\n"
-      "inline void $classname$::unsafe_arena_set_allocated_$name$("
+      "$inline$ void $classname$::unsafe_arena_set_allocated_$name$("
       "::std::string* $name$) {\n"
       "  GOOGLE_DCHECK(GetArenaNoVirtual() != NULL);\n"
       "  if (!has_$name$()) {\n"
@@ -522,15 +532,15 @@ GenerateInlineAccessorDefinitions(io::Printer* printer) const {
       "}\n");
   } else {
     // No-arena case.
-    printer->Print(variables_,
-      "inline const ::std::string& $classname$::$name$() const {\n"
+    printer->Print(variables,
+      "$inline$ const ::std::string& $classname$::$name$() const {\n"
       "  // @@protoc_insertion_point(field_get:$full_name$)\n"
       "  if (has_$name$()) {\n"
       "    return $oneof_prefix$$name$_.GetNoArena($default_variable$);\n"
       "  }\n"
       "  return *$default_variable$;\n"
       "}\n"
-      "inline void $classname$::set_$name$(const ::std::string& value) {\n"
+      "$inline$ void $classname$::set_$name$(const ::std::string& value) {\n"
       "  // @@protoc_insertion_point(field_set:$full_name$)\n"
       "  if (!has_$name$()) {\n"
       "    clear_$oneof_name$();\n"
@@ -540,7 +550,7 @@ GenerateInlineAccessorDefinitions(io::Printer* printer) const {
       "  $oneof_prefix$$name$_.SetNoArena($default_variable$, value);\n"
       "  // @@protoc_insertion_point(field_set:$full_name$)\n"
       "}\n"
-      "inline void $classname$::set_$name$(const char* value) {\n"
+      "$inline$ void $classname$::set_$name$(const char* value) {\n"
       "  if (!has_$name$()) {\n"
       "    clear_$oneof_name$();\n"
       "    set_has_$name$();\n"
@@ -550,7 +560,7 @@ GenerateInlineAccessorDefinitions(io::Printer* printer) const {
       "      $string_piece$(value));\n"
       "  // @@protoc_insertion_point(field_set_char:$full_name$)\n"
       "}\n"
-      "inline "
+      "$inline$ "
       "void $classname$::set_$name$(const $pointer_type$* value, size_t size) {\n"
       "  if (!has_$name$()) {\n"
       "    clear_$oneof_name$();\n"
@@ -561,7 +571,7 @@ GenerateInlineAccessorDefinitions(io::Printer* printer) const {
       "      reinterpret_cast<const char*>(value), size));\n"
       "  // @@protoc_insertion_point(field_set_pointer:$full_name$)\n"
       "}\n"
-      "inline ::std::string* $classname$::mutable_$name$() {\n"
+      "$inline$ ::std::string* $classname$::mutable_$name$() {\n"
       "  if (!has_$name$()) {\n"
       "    clear_$oneof_name$();\n"
       "    set_has_$name$();\n"
@@ -570,7 +580,7 @@ GenerateInlineAccessorDefinitions(io::Printer* printer) const {
       "  // @@protoc_insertion_point(field_mutable:$full_name$)\n"
       "  return $oneof_prefix$$name$_.MutableNoArena($default_variable$);\n"
       "}\n"
-      "inline ::std::string* $classname$::$release_name$() {\n"
+      "$inline$ ::std::string* $classname$::$release_name$() {\n"
       "  if (has_$name$()) {\n"
       "    clear_has_$oneof_name$();\n"
       "    return $oneof_prefix$$name$_.ReleaseNoArena($default_variable$);\n"
@@ -578,7 +588,7 @@ GenerateInlineAccessorDefinitions(io::Printer* printer) const {
       "    return NULL;\n"
       "  }\n"
       "}\n"
-      "inline void $classname$::set_allocated_$name$(::std::string* $name$) {\n"
+      "$inline$ void $classname$::set_allocated_$name$(::std::string* $name$) {\n"
       "  if (!has_$name$()) {\n"
       "    $oneof_prefix$$name$_.UnsafeSetDefault($default_variable$);\n"
       "  }\n"
@@ -670,7 +680,10 @@ GeneratePrivateMembers(io::Printer* printer) const {
 void RepeatedStringFieldGenerator::
 GenerateAccessorDeclarations(io::Printer* printer) const {
   // See comment above about unknown ctypes.
-  if (descriptor_->options().ctype() != FieldOptions::STRING) {
+  bool unknown_ctype =
+      descriptor_->options().ctype() != EffectiveStringCType(descriptor_);
+
+  if (unknown_ctype) {
     printer->Outdent();
     printer->Print(
       " private:\n"
@@ -679,26 +692,26 @@ GenerateAccessorDeclarations(io::Printer* printer) const {
   }
 
   printer->Print(variables_,
-    "inline const ::std::string& $name$(int index) const$deprecation$;\n"
-    "inline ::std::string* mutable_$name$(int index)$deprecation$;\n"
-    "inline void set_$name$(int index, const ::std::string& value)$deprecation$;\n"
-    "inline void set_$name$(int index, const char* value)$deprecation$;\n"
-    "inline "
+    "const ::std::string& $name$(int index) const$deprecation$;\n"
+    "::std::string* mutable_$name$(int index)$deprecation$;\n"
+    "void set_$name$(int index, const ::std::string& value)$deprecation$;\n"
+    "void set_$name$(int index, const char* value)$deprecation$;\n"
+    ""
     "void set_$name$(int index, const $pointer_type$* value, size_t size)"
                  "$deprecation$;\n"
-    "inline ::std::string* add_$name$()$deprecation$;\n"
-    "inline void add_$name$(const ::std::string& value)$deprecation$;\n"
-    "inline void add_$name$(const char* value)$deprecation$;\n"
-    "inline void add_$name$(const $pointer_type$* value, size_t size)"
+    "::std::string* add_$name$()$deprecation$;\n"
+    "void add_$name$(const ::std::string& value)$deprecation$;\n"
+    "void add_$name$(const char* value)$deprecation$;\n"
+    "void add_$name$(const $pointer_type$* value, size_t size)"
                  "$deprecation$;\n");
 
   printer->Print(variables_,
-    "inline const ::google::protobuf::RepeatedPtrField< ::std::string>& $name$() const"
+    "const ::google::protobuf::RepeatedPtrField< ::std::string>& $name$() const"
                  "$deprecation$;\n"
-    "inline ::google::protobuf::RepeatedPtrField< ::std::string>* mutable_$name$()"
+    "::google::protobuf::RepeatedPtrField< ::std::string>* mutable_$name$()"
                  "$deprecation$;\n");
 
-  if (descriptor_->options().ctype() != FieldOptions::STRING) {
+  if (unknown_ctype) {
     printer->Outdent();
     printer->Print(" public:\n");
     printer->Indent();
@@ -706,54 +719,57 @@ GenerateAccessorDeclarations(io::Printer* printer) const {
 }
 
 void RepeatedStringFieldGenerator::
-GenerateInlineAccessorDefinitions(io::Printer* printer) const {
-  printer->Print(variables_,
-    "inline const ::std::string& $classname$::$name$(int index) const {\n"
+GenerateInlineAccessorDefinitions(io::Printer* printer,
+                                  bool is_inline) const {
+  map<string, string> variables(variables_);
+  variables["inline"] = is_inline ? "inline" : "";
+  printer->Print(variables,
+    "$inline$ const ::std::string& $classname$::$name$(int index) const {\n"
     "  // @@protoc_insertion_point(field_get:$full_name$)\n"
     "  return $name$_.$cppget$(index);\n"
     "}\n"
-    "inline ::std::string* $classname$::mutable_$name$(int index) {\n"
+    "$inline$ ::std::string* $classname$::mutable_$name$(int index) {\n"
     "  // @@protoc_insertion_point(field_mutable:$full_name$)\n"
     "  return $name$_.Mutable(index);\n"
     "}\n"
-    "inline void $classname$::set_$name$(int index, const ::std::string& value) {\n"
+    "$inline$ void $classname$::set_$name$(int index, const ::std::string& value) {\n"
     "  // @@protoc_insertion_point(field_set:$full_name$)\n"
     "  $name$_.Mutable(index)->assign(value);\n"
     "}\n"
-    "inline void $classname$::set_$name$(int index, const char* value) {\n"
+    "$inline$ void $classname$::set_$name$(int index, const char* value) {\n"
     "  $name$_.Mutable(index)->assign(value);\n"
     "  // @@protoc_insertion_point(field_set_char:$full_name$)\n"
     "}\n"
-    "inline void "
+    "$inline$ void "
     "$classname$::set_$name$"
     "(int index, const $pointer_type$* value, size_t size) {\n"
     "  $name$_.Mutable(index)->assign(\n"
     "    reinterpret_cast<const char*>(value), size);\n"
     "  // @@protoc_insertion_point(field_set_pointer:$full_name$)\n"
     "}\n"
-    "inline ::std::string* $classname$::add_$name$() {\n"
+    "$inline$ ::std::string* $classname$::add_$name$() {\n"
     "  return $name$_.Add();\n"
     "}\n"
-    "inline void $classname$::add_$name$(const ::std::string& value) {\n"
+    "$inline$ void $classname$::add_$name$(const ::std::string& value) {\n"
     "  $name$_.Add()->assign(value);\n"
     "  // @@protoc_insertion_point(field_add:$full_name$)\n"
     "}\n"
-    "inline void $classname$::add_$name$(const char* value) {\n"
+    "$inline$ void $classname$::add_$name$(const char* value) {\n"
     "  $name$_.Add()->assign(value);\n"
     "  // @@protoc_insertion_point(field_add_char:$full_name$)\n"
     "}\n"
-    "inline void "
+    "$inline$ void "
     "$classname$::add_$name$(const $pointer_type$* value, size_t size) {\n"
     "  $name$_.Add()->assign(reinterpret_cast<const char*>(value), size);\n"
     "  // @@protoc_insertion_point(field_add_pointer:$full_name$)\n"
     "}\n");
-  printer->Print(variables_,
-    "inline const ::google::protobuf::RepeatedPtrField< ::std::string>&\n"
+  printer->Print(variables,
+    "$inline$ const ::google::protobuf::RepeatedPtrField< ::std::string>&\n"
     "$classname$::$name$() const {\n"
     "  // @@protoc_insertion_point(field_list:$full_name$)\n"
     "  return $name$_;\n"
     "}\n"
-    "inline ::google::protobuf::RepeatedPtrField< ::std::string>*\n"
+    "$inline$ ::google::protobuf::RepeatedPtrField< ::std::string>*\n"
     "$classname$::mutable_$name$() {\n"
     "  // @@protoc_insertion_point(field_mutable_list:$full_name$)\n"
     "  return &$name$_;\n"
diff --git a/src/google/protobuf/compiler/cpp/cpp_string_field.h b/src/google/protobuf/compiler/cpp/cpp_string_field.h
index 0a5ca440..d1f19cd9 100644
--- a/src/google/protobuf/compiler/cpp/cpp_string_field.h
+++ b/src/google/protobuf/compiler/cpp/cpp_string_field.h
@@ -54,7 +54,8 @@ class StringFieldGenerator : public FieldGenerator {
   void GeneratePrivateMembers(io::Printer* printer) const;
   void GenerateStaticMembers(io::Printer* printer) const;
   void GenerateAccessorDeclarations(io::Printer* printer) const;
-  void GenerateInlineAccessorDefinitions(io::Printer* printer) const;
+  void GenerateInlineAccessorDefinitions(io::Printer* printer,
+                                         bool is_inline) const;
   void GenerateNonInlineAccessorDefinitions(io::Printer* printer) const;
   void GenerateClearingCode(io::Printer* printer) const;
   void GenerateMergingCode(io::Printer* printer) const;
@@ -83,7 +84,8 @@ class StringOneofFieldGenerator : public StringFieldGenerator {
   ~StringOneofFieldGenerator();
 
   // implements FieldGenerator ---------------------------------------
-  void GenerateInlineAccessorDefinitions(io::Printer* printer) const;
+  void GenerateInlineAccessorDefinitions(io::Printer* printer,
+                                         bool is_inline) const;
   void GenerateClearingCode(io::Printer* printer) const;
   void GenerateSwappingCode(io::Printer* printer) const;
   void GenerateConstructorCode(io::Printer* printer) const;
@@ -103,7 +105,8 @@ class RepeatedStringFieldGenerator : public FieldGenerator {
   // implements FieldGenerator ---------------------------------------
   void GeneratePrivateMembers(io::Printer* printer) const;
   void GenerateAccessorDeclarations(io::Printer* printer) const;
-  void GenerateInlineAccessorDefinitions(io::Printer* printer) const;
+  void GenerateInlineAccessorDefinitions(io::Printer* printer,
+                                         bool is_inline) const;
   void GenerateClearingCode(io::Printer* printer) const;
   void GenerateMergingCode(io::Printer* printer) const;
   void GenerateSwappingCode(io::Printer* printer) const;