Revert https://codereview.chromium.org/1291903002 (protobuf roll).

third_party/protobuf/src/google/protobuf/repeated_field.h

Index: third_party/protobuf/src/google/protobuf/repeated_field.h
diff --git a/third_party/protobuf/src/google/protobuf/repeated_field.h b/third_party/protobuf/src/google/protobuf/repeated_field.h
index 03577ea5584a6f87f8d80c01c43bf8b5eda0bdf1..ff5d1f4b5f40d65ab75d0107f7ff72c99744571c 100644
--- a/third_party/protobuf/src/google/protobuf/repeated_field.h
+++ b/third_party/protobuf/src/google/protobuf/repeated_field.h
@@ -1,6 +1,6 @@
 // Protocol Buffers - Google's data interchange format
 // Copyright 2008 Google Inc.  All rights reserved.
-// https://developers.google.com/protocol-buffers/
+// http://code.google.com/p/protobuf/
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
@@ -46,17 +46,11 @@
 #ifndef GOOGLE_PROTOBUF_REPEATED_FIELD_H__
 #define GOOGLE_PROTOBUF_REPEATED_FIELD_H__
 
-#ifdef _MSC_VER
-// This is required for min/max on VS2013 only.
 #include <algorithm>
-#endif
-
 #include <string>
 #include <iterator>
-#include <google/protobuf/stubs/casts.h>
 #include <google/protobuf/stubs/common.h>
 #include <google/protobuf/stubs/type_traits.h>
-#include <google/protobuf/arena.h>
 #include <google/protobuf/generated_message_util.h>
 #include <google/protobuf/message_lite.h>
 
@@ -78,23 +72,6 @@ static const int kMinRepeatedFieldAllocationSize = 4;
 
 // A utility function for logging that doesn't need any template types.
 void LogIndexOutOfBounds(int index, int size);
-
-template <typename Iter>
-inline int CalculateReserve(Iter begin, Iter end, std::forward_iterator_tag) {
-  return std::distance(begin, end);
-}
-
-template <typename Iter>
-inline int CalculateReserve(Iter /*begin*/, Iter /*end*/,
-                            std::input_iterator_tag /*unused*/) {
-  return -1;
-}
-
-template <typename Iter>
-inline int CalculateReserve(Iter begin, Iter end) {
-  typedef typename std::iterator_traits<Iter>::iterator_category Category;
-  return CalculateReserve(begin, end, Category());
-}
 }  // namespace internal
 
 
@@ -106,7 +83,6 @@ template <typename Element>
 class RepeatedField {
  public:
   RepeatedField();
-  explicit RepeatedField(Arena* arena);
   RepeatedField(const RepeatedField& other);
   template <typename Iter>
   RepeatedField(Iter begin, const Iter& end);
@@ -114,7 +90,6 @@ class RepeatedField {
 
   RepeatedField& operator=(const RepeatedField& other);
 
-  bool empty() const;
   int size() const;
 
   const Element& Get(int index) const;
@@ -146,26 +121,14 @@ class RepeatedField {
   Element* AddAlreadyReserved();
   int Capacity() const;
 
-  // Like STL resize.  Uses value to fill appended elements.
-  // Like Truncate() if new_size <= size(), otherwise this is
-  // O(new_size - size()).
-  void Resize(int new_size, const Element& value);
-
   // Gets the underlying array.  This pointer is possibly invalidated by
   // any add or remove operation.
   Element* mutable_data();
   const Element* data() const;
 
-  // Swap entire contents with "other". If they are separate arenas then, copies
-  // data between each other.
+  // Swap entire contents with "other".
   void Swap(RepeatedField* other);
 
-  // Swap entire contents with "other". Should be called only if the caller can
-  // guarantee that both repeated fields are on the same arena or are on the
-  // heap. Swapping between different arenas is disallowed and caught by a
-  // GOOGLE_DCHECK (see API docs for details).
-  void UnsafeArenaSwap(RepeatedField* other);
-
   // Swap two elements.
   void SwapElements(int index1, int index2);
 
@@ -182,10 +145,8 @@ class RepeatedField {
 
   iterator begin();
   const_iterator begin() const;
-  const_iterator cbegin() const;
   iterator end();
   const_iterator end() const;
-  const_iterator cend() const;
 
   // Reverse iterator support
   typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
@@ -207,67 +168,22 @@ class RepeatedField {
   // sizeof(*this)
   int SpaceUsedExcludingSelf() const;
 
-  // Remove the element referenced by position.
-  iterator erase(const_iterator position);
-
-  // Remove the elements in the range [first, last).
-  iterator erase(const_iterator first, const_iterator last);
-
-  // Get the Arena on which this RepeatedField stores its elements.
-  ::google::protobuf::Arena* GetArena() const {
-    return GetArenaNoVirtual();
-  }
-
  private:
   static const int kInitialSize = 0;
-  // A note on the representation here (see also comment below for
-  // RepeatedPtrFieldBase's struct Rep):
-  //
-  // We maintain the same sizeof(RepeatedField) as before we added arena support
-  // so that we do not degrade performance by bloating memory usage. Directly
-  // adding an arena_ element to RepeatedField is quite costly. By using
-  // indirection in this way, we keep the same size when the RepeatedField is
-  // empty (common case), and add only an 8-byte header to the elements array
-  // when non-empty. We make sure to place the size fields directly in the
-  // RepeatedField class to avoid costly cache misses due to the indirection.
-  int current_size_;
-  int total_size_;
-  struct Rep {
-    Arena* arena;
-    Element  elements[1];
-  };
-  // We can not use sizeof(Rep) - sizeof(Element) due to the trailing padding on
-  // the struct. We can not use sizeof(Arena*) as well because there might be
-  // a "gap" after the field arena and before the field elements (e.g., when
-  // Element is double and pointer is 32bit).
-  static const size_t kRepHeaderSize;
-  // Contains arena ptr and the elements array. We also keep the invariant that
-  // if rep_ is NULL, then arena is NULL.
-  Rep* rep_;
-
-  friend class Arena;
-  typedef void InternalArenaConstructable_;
+
+  Element* elements_;
+  int      current_size_;
+  int      total_size_;
 
   // Move the contents of |from| into |to|, possibly clobbering |from| in the
   // process.  For primitive types this is just a memcpy(), but it could be
   // specialized for non-primitive types to, say, swap each element instead.
-  void MoveArray(Element* to, Element* from, int size);
+  void MoveArray(Element to[], Element from[], int size);
 
   // Copy the elements of |from| into |to|.
-  void CopyArray(Element* to, const Element* from, int size);
-
-  inline void InternalSwap(RepeatedField* other);
-
-  // Internal helper expected by Arena methods.
-  inline Arena* GetArenaNoVirtual() const {
-    return (rep_ == NULL) ? NULL : rep_->arena;
-  }
+  void CopyArray(Element to[], const Element from[], int size);
 };
 
-template<typename Element>
-const size_t RepeatedField<Element>::kRepHeaderSize =
-    reinterpret_cast<size_t>(&reinterpret_cast<Rep*>(16)->elements[0]) - 16;
-
 namespace internal {
 template <typename It> class RepeatedPtrIterator;
 template <typename It, typename VoidPtr> class RepeatedPtrOverPtrsIterator;
@@ -282,48 +198,13 @@ namespace internal {
 template <typename Element,
           bool HasTrivialCopy = has_trivial_copy<Element>::value>
 struct ElementCopier {
-  void operator()(Element* to, const Element* from, int array_size);
+  void operator()(Element to[], const Element from[], int array_size);
 };
 
 }  // namespace internal
 
 namespace internal {
 
-// type-traits helper for RepeatedPtrFieldBase: we only want to invoke
-// arena-related "copy if on different arena" behavior if the necessary methods
-// exist on the contained type. In particular, we rely on MergeFrom() existing
-// as a general proxy for the fact that a copy will work, and we also provide a
-// specific override for string*.
-template<typename T>
-struct TypeImplementsMergeBehavior {
-  typedef char HasMerge;
-  typedef long HasNoMerge;
-
-  // We accept either of:
-  // - void MergeFrom(const T& other)
-  // - bool MergeFrom(const T& other)
-  //
-  // We mangle these names a bit to avoid compatibility issues in 'unclean'
-  // include environments that may have, e.g., "#define test ..." (yes, this
-  // exists).
-  template<typename U, typename RetType, RetType (U::*)(const U& arg)>
-      struct CheckType;
-  template<typename U> static HasMerge Check(
-      CheckType<U, void, &U::MergeFrom>*);
-  template<typename U> static HasMerge Check(
-      CheckType<U, bool, &U::MergeFrom>*);
-  template<typename U> static HasNoMerge Check(...);
-
-  // Resovles to either google::protobuf::internal::true_type or google::protobuf::internal::false_type.
-  typedef google::protobuf::internal::integral_constant<bool,
-               (sizeof(Check<T>(0)) == sizeof(HasMerge))> type;
-};
-
-template<>
-struct TypeImplementsMergeBehavior< ::std::string > {
-  typedef google::protobuf::internal::true_type type;
-};
-
 // This is the common base class for RepeatedPtrFields.  It deals only in void*
 // pointers.  Users should not use this interface directly.
 //
@@ -354,24 +235,16 @@ class LIBPROTOBUF_EXPORT RepeatedPtrFieldBase {
   // use of AddFromCleared(), which is not part of the public interface.
   friend class ExtensionSet;
 
-  // The MapFieldBase implementation needs to call protected methods directly,
-  // reinterpreting pointers as being to Message instead of a specific Message
-  // subclass.
-  friend class MapFieldBase;
-
   // To parse directly into a proto2 generated class, the upb class GMR_Handlers
   // needs to be able to modify a RepeatedPtrFieldBase directly.
   friend class LIBPROTOBUF_EXPORT upb::google_opensource::GMR_Handlers;
 
   RepeatedPtrFieldBase();
-  explicit RepeatedPtrFieldBase(::google::protobuf::Arena* arena);
-  ~RepeatedPtrFieldBase() {}
 
   // Must be called from destructor.
   template <typename TypeHandler>
   void Destroy();
 
-  bool empty() const;
   int size() const;
 
   template <typename TypeHandler>
@@ -379,10 +252,7 @@ class LIBPROTOBUF_EXPORT RepeatedPtrFieldBase {
   template <typename TypeHandler>
   typename TypeHandler::Type* Mutable(int index);
   template <typename TypeHandler>
-  void Delete(int index);
-  template <typename TypeHandler>
-  typename TypeHandler::Type* Add(typename TypeHandler::Type* prototype = NULL);
-
+  typename TypeHandler::Type* Add();
   template <typename TypeHandler>
   void RemoveLast();
   template <typename TypeHandler>
@@ -392,7 +262,13 @@ class LIBPROTOBUF_EXPORT RepeatedPtrFieldBase {
   template <typename TypeHandler>
   void CopyFrom(const RepeatedPtrFieldBase& other);
 
-  void CloseGap(int start, int num);
+  void CloseGap(int start, int num) {
+    // Close up a gap of "num" elements starting at offset "start".
+    for (int i = start + num; i < allocated_size_; ++i)
+      elements_[i - num] = elements_[i];
+    current_size_ -= num;
+    allocated_size_ -= num;
+  }
 
   void Reserve(int new_size);
 
@@ -407,8 +283,7 @@ class LIBPROTOBUF_EXPORT RepeatedPtrFieldBase {
   template <typename TypeHandler>
   const typename TypeHandler::Type* const* data() const;
 
-  template <typename TypeHandler>
-  inline void Swap(RepeatedPtrFieldBase* other) GOOGLE_ATTRIBUTE_ALWAYS_INLINE;
+  void Swap(RepeatedPtrFieldBase* other);
 
   void SwapElements(int index1, int index2);
 
@@ -422,25 +297,10 @@ class LIBPROTOBUF_EXPORT RepeatedPtrFieldBase {
   template <typename TypeHandler>
   typename TypeHandler::Type* AddFromCleared();
 
-  template<typename TypeHandler>
-  void AddAllocated(typename TypeHandler::Type* value) {
-    typename TypeImplementsMergeBehavior<typename TypeHandler::Type>::type t;
-    AddAllocatedInternal<TypeHandler>(value, t);
-  }
-
   template <typename TypeHandler>
-  void UnsafeArenaAddAllocated(typename TypeHandler::Type* value);
-
+  void AddAllocated(typename TypeHandler::Type* value);
   template <typename TypeHandler>
-  typename TypeHandler::Type* ReleaseLast() {
-    typename TypeImplementsMergeBehavior<typename TypeHandler::Type>::type t;
-    return ReleaseLastInternal<TypeHandler>(t);
-  }
-
-  // Releases last element and returns it, but does not do out-of-arena copy.
-  // And just returns the raw pointer to the contained element in the arena.
-  template <typename TypeHandler>
-  typename TypeHandler::Type* UnsafeArenaReleaseLast();
+  typename TypeHandler::Type* ReleaseLast();
 
   int ClearedCount() const;
   template <typename TypeHandler>
@@ -448,61 +308,15 @@ class LIBPROTOBUF_EXPORT RepeatedPtrFieldBase {
   template <typename TypeHandler>
   typename TypeHandler::Type* ReleaseCleared();
 
- protected:
-  inline void InternalSwap(RepeatedPtrFieldBase* other);
-
-  template <typename TypeHandler>
-  void AddAllocatedInternal(typename TypeHandler::Type* value,
-                            google::protobuf::internal::true_type);
-  template <typename TypeHandler>
-  void AddAllocatedInternal(typename TypeHandler::Type* value,
-                            google::protobuf::internal::false_type);
-
-  template <typename TypeHandler>
-  void AddAllocatedSlowWithCopy(typename TypeHandler::Type* value,
-                                Arena* value_arena,
-                                Arena* my_arena)
-      GOOGLE_ATTRIBUTE_NOINLINE;
-  template <typename TypeHandler>
-  void AddAllocatedSlowWithoutCopy(typename TypeHandler::Type* value)
-      GOOGLE_ATTRIBUTE_NOINLINE;
-
-  template <typename TypeHandler>
-  typename TypeHandler::Type* ReleaseLastInternal(google::protobuf::internal::true_type);
-  template <typename TypeHandler>
-  typename TypeHandler::Type* ReleaseLastInternal(google::protobuf::internal::false_type);
-
-  template<typename TypeHandler>
-  inline void SwapFallback(RepeatedPtrFieldBase* other) GOOGLE_ATTRIBUTE_NOINLINE;
-
-  inline Arena* GetArenaNoVirtual() const {
-    return arena_;
-  }
-
  private:
+  GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(RepeatedPtrFieldBase);
+
   static const int kInitialSize = 0;
-  // A few notes on internal representation:
-  //
-  // We use an indirected approach, with struct Rep, to keep
-  // sizeof(RepeatedPtrFieldBase) equivalent to what it was before arena support
-  // was added, namely, 3 8-byte machine words on x86-64. An instance of Rep is
-  // allocated only when the repeated field is non-empty, and it is a
-  // dynamically-sized struct (the header is directly followed by elements[]).
-  // We place arena_ and current_size_ directly in the object to avoid cache
-  // misses due to the indirection, because these fields are checked frequently.
-  // Placing all fields directly in the RepeatedPtrFieldBase instance costs
-  // significant performance for memory-sensitive workloads.
-  Arena* arena_;
+
+  void** elements_;
   int    current_size_;
+  int    allocated_size_;
   int    total_size_;
-  struct Rep {
-    int    allocated_size;
-    void*  elements[1];
-  };
-  static const size_t kRepHeaderSize = sizeof(Rep) - sizeof(void*);
-  // Contains arena ptr and the elements array. We also keep the invariant that
-  // if rep_ is NULL, then arena is NULL.
-  Rep* rep_;
 
   template <typename TypeHandler>
   static inline typename TypeHandler::Type* cast(void* element) {
@@ -512,122 +326,27 @@ class LIBPROTOBUF_EXPORT RepeatedPtrFieldBase {
   static inline const typename TypeHandler::Type* cast(const void* element) {
     return reinterpret_cast<const typename TypeHandler::Type*>(element);
   }
-
-  // Non-templated inner function to avoid code duplication. Takes a function
-  // pointer to the type-specific (templated) inner allocate/merge loop.
-  void MergeFromInternal(
-      const RepeatedPtrFieldBase& other,
-      void (RepeatedPtrFieldBase::*inner_loop)(void**, void**, int, int));
-
-  template<typename TypeHandler>
-  void MergeFromInnerLoop(
-      void** our_elems, void** other_elems, int length, int already_allocated);
-
-  // Internal helper: extend array space if necessary to contain |extend_amount|
-  // more elements, and return a pointer to the element immediately following
-  // the old list of elements.  This interface factors out common behavior from
-  // Reserve() and MergeFrom() to reduce code size. |extend_amount| must be > 0.
-  void** InternalExtend(int extend_amount);
-
-  GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(RepeatedPtrFieldBase);
 };
 
 template <typename GenericType>
 class GenericTypeHandler {
  public:
   typedef GenericType Type;
-  static inline GenericType* New(Arena* arena) {
-    return ::google::protobuf::Arena::CreateMaybeMessage<Type>(
-        arena, static_cast<GenericType*>(0));
-  }
-  // We force NewFromPrototype() and Delete() to be non-inline to reduce code
-  // size: else, several other methods get inlined copies of message types'
-  // constructors and destructors. Note that the GOOGLE_ATTRIBUTE_NOINLINE macro
-  // requires the 'inline' storage class here, which is somewhat confusing, but
-  // the compiler does the right thing.
-  static GenericType* NewFromPrototype(const GenericType* prototype,
-                                       ::google::protobuf::Arena* arena = NULL)
-      GOOGLE_ATTRIBUTE_NOINLINE;
-  static void Delete(GenericType* value, Arena* arena)
-      GOOGLE_ATTRIBUTE_NOINLINE;
-  static inline ::google::protobuf::Arena* GetArena(GenericType* value) {
-    return ::google::protobuf::Arena::GetArena<Type>(value);
-  }
-  static inline void* GetMaybeArenaPointer(GenericType* value) {
-    return ::google::protobuf::Arena::GetArena<Type>(value);
-  }
-
-  static inline void Clear(GenericType* value) { value->Clear(); }
-  static void Merge(const GenericType& from, GenericType* to)
-      GOOGLE_ATTRIBUTE_NOINLINE;
-  static inline int SpaceUsed(const GenericType& value) {
-    return value.SpaceUsed();
-  }
-  static inline const Type& default_instance() {
-    return Type::default_instance();
-  }
+  static GenericType* New() { return new GenericType; }
+  static void Delete(GenericType* value) { delete value; }
+  static void Clear(GenericType* value) { value->Clear(); }
+  static void Merge(const GenericType& from, GenericType* to) {
+    to->MergeFrom(from);
+  }
+  static int SpaceUsed(const GenericType& value) { return value.SpaceUsed(); }
+  static const Type& default_instance() { return Type::default_instance(); }
 };
 
-template<typename GenericType>
-GenericType* GenericTypeHandler<GenericType>::NewFromPrototype(
-    const GenericType* prototype,
-    ::google::protobuf::Arena* arena) {
-  return New(arena);
-}
-template<typename GenericType>
-void GenericTypeHandler<GenericType>::Delete(GenericType* value, Arena* arena) {
-  if (arena == NULL) {
-    delete value;
-  }
-}
-template<typename GenericType>
-void GenericTypeHandler<GenericType>::Merge(const GenericType& from,
-                                            GenericType* to) {
-  to->MergeFrom(from);
-}
-
-// NewFromPrototype() and Merge() cannot be defined here; if they're declared
-// inline the compiler will complain about not matching ATTRIBUTE_NOINLINE
-// above, and if not, compilation will result in multiple definitions.  These
-// are therefore declared as specializations here and defined in
-// message_lite.cc.
-template<>
-MessageLite* GenericTypeHandler<MessageLite>::NewFromPrototype(
-    const MessageLite* prototype, google::protobuf::Arena* arena);
-template<>
-inline google::protobuf::Arena* GenericTypeHandler<MessageLite>::GetArena(
-    MessageLite* value) {
-  return value->GetArena();
-}
-template<>
-inline void* GenericTypeHandler<MessageLite>::GetMaybeArenaPointer(
-    MessageLite* value) {
-  return value->GetMaybeArenaPointer();
-}
 template <>
-void GenericTypeHandler<MessageLite>::Merge(const MessageLite& from,
-                                            MessageLite* to);
-
-// Declarations of the specialization as we cannot define them here, as the
-// header that defines ProtocolMessage depends on types defined in this header.
-#define DECLARE_SPECIALIZATIONS_FOR_BASE_PROTO_TYPES(TypeName)                 \
-    template<>                                                                 \
-    TypeName* GenericTypeHandler<TypeName>::NewFromPrototype(                  \
-        const TypeName* prototype, google::protobuf::Arena* arena);                      \
-    template<>                                                                 \
-    google::protobuf::Arena* GenericTypeHandler<TypeName>::GetArena(                     \
-        TypeName* value);                                                      \
-    template<>                                                                 \
-    void* GenericTypeHandler<TypeName>::GetMaybeArenaPointer(                  \
-        TypeName* value);
-
-// Message specialization bodies defined in message.cc. This split is necessary
-// to allow proto2-lite (which includes this header) to be independent of
-// Message.
-DECLARE_SPECIALIZATIONS_FOR_BASE_PROTO_TYPES(Message);
-
-
-#undef DECLARE_SPECIALIZATIONS_FOR_BASE_PROTO_TYPES
+inline void GenericTypeHandler<MessageLite>::Merge(
+    const MessageLite& from, MessageLite* to) {
+  to->CheckTypeAndMergeFrom(from);
+}
 
 template <>
 inline const MessageLite& GenericTypeHandler<MessageLite>::default_instance() {
@@ -659,28 +378,11 @@ inline const Message& GenericTypeHandler<Message>::default_instance() {
 class LIBPROTOBUF_EXPORT StringTypeHandlerBase {
  public:
   typedef string Type;
-
-  static inline string* New(Arena* arena) {
-    return Arena::Create<string>(arena);
-  }
-  static inline string* NewFromPrototype(const string*,
-                                         ::google::protobuf::Arena* arena) {
-    return New(arena);
-  }
-  static inline ::google::protobuf::Arena* GetArena(string*) {
-    return NULL;
-  }
-  static inline void* GetMaybeArenaPointer(string* value) {
-    return NULL;
-  }
-  static inline void Delete(string* value, Arena* arena) {
-    if (arena == NULL) {
-      delete value;
-    }
-  }
-  static inline void Clear(string* value) { value->clear(); }
-  static inline void Merge(const string& from, string* to) { *to = from; }
-  static inline const Type& default_instance() {
+  static string* New();
+  static void Delete(string* value);
+  static void Clear(string* value) { value->clear(); }
+  static void Merge(const string& from, string* to) { *to = from; }
+  static const Type& default_instance() {
     return ::google::protobuf::internal::GetEmptyString();
   }
 };
@@ -701,8 +403,6 @@ template <typename Element>
 class RepeatedPtrField : public internal::RepeatedPtrFieldBase {
  public:
   RepeatedPtrField();
-  explicit RepeatedPtrField(::google::protobuf::Arena* arena);
-
   RepeatedPtrField(const RepeatedPtrField& other);
   template <typename Iter>
   RepeatedPtrField(Iter begin, const Iter& end);
@@ -710,7 +410,6 @@ class RepeatedPtrField : public internal::RepeatedPtrFieldBase {
 
   RepeatedPtrField& operator=(const RepeatedPtrField& other);
 
-  bool empty() const;
   int size() const;
 
   const Element& Get(int index) const;
@@ -742,16 +441,9 @@ class RepeatedPtrField : public internal::RepeatedPtrFieldBase {
   Element** mutable_data();
   const Element* const* data() const;
 
-  // Swap entire contents with "other". If they are on separate arenas, then
-  // copies data.
+  // Swap entire contents with "other".
   void Swap(RepeatedPtrField* other);
 
-  // Swap entire contents with "other". Caller should guarantee that either both
-  // fields are on the same arena or both are on the heap. Swapping between
-  // different arenas with this function is disallowed and is caught via
-  // GOOGLE_DCHECK.
-  void UnsafeArenaSwap(RepeatedPtrField* other);
-
   // Swap two elements.
   void SwapElements(int index1, int index2);
 
@@ -768,10 +460,8 @@ class RepeatedPtrField : public internal::RepeatedPtrFieldBase {
 
   iterator begin();
   const_iterator begin() const;
-  const_iterator cbegin() const;
   iterator end();
   const_iterator end() const;
-  const_iterator cend() const;
 
   // Reverse iterator support
   typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
@@ -810,36 +500,11 @@ class RepeatedPtrField : public internal::RepeatedPtrFieldBase {
 
   // Add an already-allocated object, passing ownership to the
   // RepeatedPtrField.
-  //
-  // Note that some special behavior occurs with respect to arenas:
-  //
-  //   (i) if this field holds submessages, the new submessage will be copied if
-  //   the original is in an arena and this RepeatedPtrField is either in a
-  //   different arena, or on the heap.
-  //   (ii) if this field holds strings, the passed-in string *must* be
-  //   heap-allocated, not arena-allocated. There is no way to dynamically check
-  //   this at runtime, so User Beware.
   void AddAllocated(Element* value);
-
   // Remove the last element and return it, passing ownership to the caller.
   // Requires:  size() > 0
-  //
-  // If this RepeatedPtrField is on an arena, an object copy is required to pass
-  // ownership back to the user (for compatible semantics). Use
-  // UnsafeArenaReleaseLast() if this behavior is undesired.
   Element* ReleaseLast();
 
-  // Add an already-allocated object, skipping arena-ownership checks. The user
-  // must guarantee that the given object is in the same arena as this
-  // RepeatedPtrField.
-  void UnsafeArenaAddAllocated(Element* value);
-
-  // Remove the last element and return it.  Works only when operating on an
-  // arena. The returned pointer is to the original object in the arena, hence
-  // has the arena's lifetime.
-  // Requires:  current_size_ > 0
-  Element* UnsafeArenaReleaseLast();
-
   // Extract elements with indices in the range "[start .. start+num-1]".
   // The caller assumes ownership of the extracted elements and is responsible
   // for deleting them when they are no longer needed.
@@ -849,20 +514,8 @@ class RepeatedPtrField : public internal::RepeatedPtrFieldBase {
   // to perform any further operations (like deletion) on these elements.
   // Caution: implementation also moves elements with indices [start+num ..].
   // Calling this routine inside a loop can cause quadratic behavior.
-  //
-  // Memory copying behavior is identical to ReleaseLast(), described above: if
-  // this RepeatedPtrField is on an arena, an object copy is performed for each
-  // returned element, so that all returned element pointers are to
-  // heap-allocated copies. If this copy is not desired, the user should call
-  // UnsafeArenaExtractSubrange().
   void ExtractSubrange(int start, int num, Element** elements);
 
-  // Identical to ExtractSubrange() described above, except that when this
-  // repeated field is on an arena, no object copies are performed. Instead, the
-  // raw object pointers are returned. Thus, if on an arena, the returned
-  // objects must not be freed, because they will not be heap-allocated objects.
-  void UnsafeArenaExtractSubrange(int start, int num, Element** elements);
-
   // When elements are removed by calls to RemoveLast() or Clear(), they
   // are not actually freed.  Instead, they are cleared and kept so that
   // they can be reused later.  This can save lots of CPU time when
@@ -877,30 +530,12 @@ class RepeatedPtrField : public internal::RepeatedPtrFieldBase {
   // Add an element to the pool of cleared objects, passing ownership to
   // the RepeatedPtrField.  The element must be cleared prior to calling
   // this method.
-  //
-  // This method cannot be called when the repeated field is on an arena or when
-  // |value| is; both cases will trigger a GOOGLE_DCHECK-failure.
   void AddCleared(Element* value);
   // Remove a single element from the cleared pool and return it, passing
   // ownership to the caller.  The element is guaranteed to be cleared.
   // Requires:  ClearedCount() > 0
-  //
-  //
-  // This method cannot be called when the repeated field is on an arena; doing
-  // so will trigger a GOOGLE_DCHECK-failure.
   Element* ReleaseCleared();
 
-  // Remove the element referenced by position.
-  iterator erase(const_iterator position);
-
-  // Removes the elements in the range [first, last).
-  iterator erase(const_iterator first, const_iterator last);
-
-  // Gets the arena on which this RepeatedPtrField stores its elements.
-  ::google::protobuf::Arena* GetArena() const {
-    return GetArenaNoVirtual();
-  }
-
  protected:
   // Note:  RepeatedPtrField SHOULD NOT be subclassed by users.  We only
   //   subclass it in one place as a hack for compatibility with proto1.  The
@@ -908,90 +543,39 @@ class RepeatedPtrField : public internal::RepeatedPtrFieldBase {
   //   methods on RepeatedPtrFieldBase.
   class TypeHandler;
 
-  // Internal arena accessor expected by helpers in Arena.
-  inline Arena* GetArenaNoVirtual() const;
-
- private:
-  // Implementations for ExtractSubrange(). The copying behavior must be
-  // included only if the type supports the necessary operations (e.g.,
-  // MergeFrom()), so we must resolve this at compile time. ExtractSubrange()
-  // uses SFINAE to choose one of the below implementations.
-  void ExtractSubrangeInternal(int start, int num, Element** elements,
-                               google::protobuf::internal::true_type);
-  void ExtractSubrangeInternal(int start, int num, Element** elements,
-                               google::protobuf::internal::false_type);
-
-  friend class Arena;
-  typedef void InternalArenaConstructable_;
-
 };
 
 // implementation ====================================================
 
 template <typename Element>
 inline RepeatedField<Element>::RepeatedField()
-  : current_size_(0),
-    total_size_(0),
-    rep_(NULL) {
-}
-
-template <typename Element>
-inline RepeatedField<Element>::RepeatedField(Arena* arena)
-  : current_size_(0),
-    total_size_(0),
-    rep_(NULL) {
- // In case arena is NULL, then we do not create rep_, as code has an invariant
- // `rep_ == NULL then arena == NULL`.
- if (arena != NULL) {
-  rep_ = reinterpret_cast<Rep*>(
-      ::google::protobuf::Arena::CreateArray<char>(arena, kRepHeaderSize));
-  rep_->arena = arena;
- }
+  : elements_(NULL),
+    current_size_(0),
+    total_size_(kInitialSize) {
 }
 
 template <typename Element>
 inline RepeatedField<Element>::RepeatedField(const RepeatedField& other)
-  : current_size_(0),
-    total_size_(0),
-    rep_(NULL) {
+  : elements_(NULL),
+    current_size_(0),
+    total_size_(kInitialSize) {
   CopyFrom(other);
 }
 
 template <typename Element>
 template <typename Iter>
-RepeatedField<Element>::RepeatedField(Iter begin, const Iter& end)
-  : current_size_(0),
-    total_size_(0),
-    rep_(NULL) {
-  int reserve = internal::CalculateReserve(begin, end);
-  if (reserve != -1) {
-    Reserve(reserve);
-    for (; begin != end; ++begin) {
-      AddAlreadyReserved(*begin);
-    }
-  } else {
-    for (; begin != end; ++begin) {
-      Add(*begin);
-    }
+inline RepeatedField<Element>::RepeatedField(Iter begin, const Iter& end)
+  : elements_(NULL),
+    current_size_(0),
+    total_size_(kInitialSize) {
+  for (; begin != end; ++begin) {
+    Add(*begin);
   }
 }
 
 template <typename Element>
 RepeatedField<Element>::~RepeatedField() {
-  // See explanation in Reserve(): we need to invoke destructors here for the
-  // case that Element has a non-trivial destructor. If Element has a trivial
-  // destructor (for example, if it's a primitive type, like int32), this entire
-  // loop will be removed by the optimizer.
-  if (rep_ != NULL) {
-    Element* e = &rep_->elements[0];
-    Element* limit = &rep_->elements[total_size_];
-    for (; e < limit; e++) {
-      e->Element::~Element();
-    }
-    if (rep_->arena == NULL) {
-      delete[] reinterpret_cast<char*>(rep_);
-    }
-  }
+  delete [] elements_;
 }
 
 template <typename Element>
@@ -1003,11 +587,6 @@ RepeatedField<Element>::operator=(const RepeatedField& other) {
 }
 
 template <typename Element>
-inline bool RepeatedField<Element>::empty() const {
-  return current_size_ == 0;
-}
-
-template <typename Element>
 inline int RepeatedField<Element>::size() const {
   return current_size_;
 }
@@ -1019,64 +598,50 @@ inline int RepeatedField<Element>::Capacity() const {
 
 template<typename Element>
 inline void RepeatedField<Element>::AddAlreadyReserved(const Element& value) {
-  GOOGLE_DCHECK_LT(current_size_, total_size_);
-  rep_->elements[current_size_++] = value;
+  GOOGLE_DCHECK_LT(size(), Capacity());
+  elements_[current_size_++] = value;
 }
 
 template<typename Element>
 inline Element* RepeatedField<Element>::AddAlreadyReserved() {
-  GOOGLE_DCHECK_LT(current_size_, total_size_);
-  return &rep_->elements[current_size_++];
-}
-
-template<typename Element>
-inline void RepeatedField<Element>::Resize(int new_size, const Element& value) {
-  GOOGLE_DCHECK_GE(new_size, 0);
-  if (new_size > current_size_) {
-    Reserve(new_size);
-    std::fill(&rep_->elements[current_size_],
-              &rep_->elements[new_size], value);
-  }
-  current_size_ = new_size;
+  GOOGLE_DCHECK_LT(size(), Capacity());
+  return &elements_[current_size_++];
 }
 
 template <typename Element>
 inline const Element& RepeatedField<Element>::Get(int index) const {
-  GOOGLE_DCHECK_GE(index, 0);
-  GOOGLE_DCHECK_LT(index, current_size_);
-  return rep_->elements[index];
+  GOOGLE_DCHECK_LT(index, size());
+  return elements_[index];
 }
 
 template <typename Element>
 inline Element* RepeatedField<Element>::Mutable(int index) {
-  GOOGLE_DCHECK_GE(index, 0);
-  GOOGLE_DCHECK_LT(index, current_size_);
-  return &rep_->elements[index];
+  GOOGLE_DCHECK_LT(index, size());
+  return elements_ + index;
 }
 
 template <typename Element>
 inline void RepeatedField<Element>::Set(int index, const Element& value) {
-  GOOGLE_DCHECK_GE(index, 0);
-  GOOGLE_DCHECK_LT(index, current_size_);
-  rep_->elements[index] = value;
+  GOOGLE_DCHECK_LT(index, size());
+  elements_[index] = value;
 }
 
 template <typename Element>
 inline void RepeatedField<Element>::Add(const Element& value) {
   if (current_size_ == total_size_) Reserve(total_size_ + 1);
-  rep_->elements[current_size_++] = value;
+  elements_[current_size_++] = value;
 }
 
 template <typename Element>
 inline Element* RepeatedField<Element>::Add() {
   if (current_size_ == total_size_) Reserve(total_size_ + 1);
-  return &rep_->elements[current_size_++];
+  return &elements_[current_size_++];
 }
 
 template <typename Element>
 inline void RepeatedField<Element>::RemoveLast() {
   GOOGLE_DCHECK_GT(current_size_, 0);
-  current_size_--;
+  --current_size_;
 }
 
 template <typename Element>
@@ -1084,7 +649,7 @@ void RepeatedField<Element>::ExtractSubrange(
     int start, int num, Element* elements) {
   GOOGLE_DCHECK_GE(start, 0);
   GOOGLE_DCHECK_GE(num, 0);
-  GOOGLE_DCHECK_LE(start + num, this->current_size_);
+  GOOGLE_DCHECK_LE(start + num, this->size());
 
   // Save the values of the removed elements if requested.
   if (elements != NULL) {
@@ -1094,9 +659,9 @@ void RepeatedField<Element>::ExtractSubrange(
 
   // Slide remaining elements down to fill the gap.
   if (num > 0) {
-    for (int i = start + num; i < this->current_size_; ++i)
+    for (int i = start + num; i < this->size(); ++i)
       this->Set(i - num, this->Get(i));
-    this->Truncate(this->current_size_ - num);
+    this->Truncate(this->size() - num);
   }
 }
 
@@ -1107,117 +672,75 @@ inline void RepeatedField<Element>::Clear() {
 
 template <typename Element>
 inline void RepeatedField<Element>::MergeFrom(const RepeatedField& other) {
-  GOOGLE_CHECK_NE(&other, this);
   if (other.current_size_ != 0) {
     Reserve(current_size_ + other.current_size_);
-    CopyArray(rep_->elements + current_size_,
-              other.rep_->elements, other.current_size_);
+    CopyArray(elements_ + current_size_, other.elements_, other.current_size_);
     current_size_ += other.current_size_;
   }
 }
 
 template <typename Element>
 inline void RepeatedField<Element>::CopyFrom(const RepeatedField& other) {
-  if (&other == this) return;
   Clear();
   MergeFrom(other);
 }
 
 template <typename Element>
-inline typename RepeatedField<Element>::iterator RepeatedField<Element>::erase(
-    const_iterator position) {
-  return erase(position, position + 1);
-}
-
-template <typename Element>
-inline typename RepeatedField<Element>::iterator RepeatedField<Element>::erase(
-    const_iterator first, const_iterator last) {
-  size_type first_offset = first - cbegin();
-  if (first != last) {
-    Truncate(std::copy(last, cend(), begin() + first_offset) - cbegin());
-  }
-  return begin() + first_offset;
-}
-
-template <typename Element>
 inline Element* RepeatedField<Element>::mutable_data() {
-  return rep_ ? rep_->elements : NULL;
+  return elements_;
 }
 
 template <typename Element>
 inline const Element* RepeatedField<Element>::data() const {
-  return rep_ ? rep_->elements : NULL;
+  return elements_;
 }
 
 
 template <typename Element>
-inline void RepeatedField<Element>::InternalSwap(RepeatedField* other) {
-  std::swap(rep_, other->rep_);
-  std::swap(current_size_, other->current_size_);
-  std::swap(total_size_, other->total_size_);
-}
-
-template <typename Element>
 void RepeatedField<Element>::Swap(RepeatedField* other) {
   if (this == other) return;
-  if (GetArenaNoVirtual() ==  other->GetArenaNoVirtual()) {
-    InternalSwap(other);
-  } else {
-    RepeatedField<Element> temp(other->GetArenaNoVirtual());
-    temp.MergeFrom(*this);
-    CopyFrom(*other);
-    other->UnsafeArenaSwap(&temp);
-  }
-}
+  Element* swap_elements     = elements_;
+  int      swap_current_size = current_size_;
+  int      swap_total_size   = total_size_;
 
-template <typename Element>
-void RepeatedField<Element>::UnsafeArenaSwap(RepeatedField* other) {
-  if (this == other) return;
-  GOOGLE_DCHECK(GetArenaNoVirtual() == other->GetArenaNoVirtual());
-  InternalSwap(other);
+  elements_     = other->elements_;
+  current_size_ = other->current_size_;
+  total_size_   = other->total_size_;
+
+  other->elements_     = swap_elements;
+  other->current_size_ = swap_current_size;
+  other->total_size_   = swap_total_size;
 }
 
 template <typename Element>
 void RepeatedField<Element>::SwapElements(int index1, int index2) {
-  using std::swap;  // enable ADL with fallback
-  swap(rep_->elements[index1], rep_->elements[index2]);
+  std::swap(elements_[index1], elements_[index2]);
 }
 
 template <typename Element>
 inline typename RepeatedField<Element>::iterator
 RepeatedField<Element>::begin() {
-  return rep_ ? rep_->elements : NULL;
+  return elements_;
 }
 template <typename Element>
 inline typename RepeatedField<Element>::const_iterator
 RepeatedField<Element>::begin() const {
-  return rep_ ? rep_->elements : NULL;
-}
-template <typename Element>
-inline typename RepeatedField<Element>::const_iterator
-RepeatedField<Element>::cbegin() const {
-  return rep_ ? rep_->elements : NULL;
+  return elements_;
 }
 template <typename Element>
 inline typename RepeatedField<Element>::iterator
 RepeatedField<Element>::end() {
-  return rep_ ? rep_->elements + current_size_ : NULL;
+  return elements_ + current_size_;
 }
 template <typename Element>
 inline typename RepeatedField<Element>::const_iterator
 RepeatedField<Element>::end() const {
-  return rep_ ? rep_->elements + current_size_ : NULL;
-}
-template <typename Element>
-inline typename RepeatedField<Element>::const_iterator
-RepeatedField<Element>::cend() const {
-  return rep_ ? rep_->elements + current_size_ : NULL;
+  return elements_ + current_size_;
 }
 
 template <typename Element>
 inline int RepeatedField<Element>::SpaceUsedExcludingSelf() const {
-  return rep_ ?
-      (total_size_ * sizeof(Element) + kRepHeaderSize) : 0;
+  return (elements_ != NULL) ? total_size_ * sizeof(elements_[0]) : 0;
 }
 
 // Avoid inlining of Reserve(): new, copy, and delete[] lead to a significant
@@ -1225,69 +748,32 @@ inline int RepeatedField<Element>::SpaceUsedExcludingSelf() const {
 template <typename Element>
 void RepeatedField<Element>::Reserve(int new_size) {
   if (total_size_ >= new_size) return;
-  Rep* old_rep = rep_;
-  Arena* arena = GetArenaNoVirtual();
-  new_size = max(google::protobuf::internal::kMinRepeatedFieldAllocationSize,
-                 max(total_size_ * 2, new_size));
-  if (arena == NULL) {
-    rep_ = reinterpret_cast<Rep*>(
-        new char[kRepHeaderSize + sizeof(Element)*new_size]);
-  } else {
-    rep_ = reinterpret_cast<Rep*>(
-            ::google::protobuf::Arena::CreateArray<char>(arena,
-                kRepHeaderSize + sizeof(Element)*new_size));
-  }
-  rep_->arena = arena;
-  int old_total_size = total_size_;
-  total_size_ = new_size;
-  // Invoke placement-new on newly allocated elements. We shouldn't have to do
-  // this, since Element is supposed to be POD, but a previous version of this
-  // code allocated storage with "new Element[size]" and some code uses
-  // RepeatedField with non-POD types, relying on constructor invocation. If
-  // Element has a trivial constructor (e.g., int32), gcc (tested with -O2)
-  // completely removes this loop because the loop body is empty, so this has no
-  // effect unless its side-effects are required for correctness.
-  // Note that we do this before MoveArray() below because Element's copy
-  // assignment implementation will want an initialized instance first.
-  Element* e = &rep_->elements[0];
-  Element* limit = &rep_->elements[total_size_];
-  for (; e < limit; e++) {
-    new (e) Element();
-  }
-  if (current_size_ > 0) {
-    MoveArray(rep_->elements, old_rep->elements, current_size_);
-  }
-  if (old_rep) {
-    // Likewise, we need to invoke destructors on the old array. If Element has
-    // no destructor, this loop will disappear.
-    e = &old_rep->elements[0];
-    limit = &old_rep->elements[old_total_size];
-    for (; e < limit; e++) {
-      e->Element::~Element();
-    }
-    if (arena == NULL) {
-      delete[] reinterpret_cast<char*>(old_rep);
-    }
+
+  Element* old_elements = elements_;
+  total_size_ = max(google::protobuf::internal::kMinRepeatedFieldAllocationSize,
+                    max(total_size_ * 2, new_size));
+  elements_ = new Element[total_size_];
+  if (old_elements != NULL) {
+    MoveArray(elements_, old_elements, current_size_);
+    delete [] old_elements;
   }
 }
 
 template <typename Element>
 inline void RepeatedField<Element>::Truncate(int new_size) {
   GOOGLE_DCHECK_LE(new_size, current_size_);
-  if (current_size_ > 0) {
-    current_size_ = new_size;
-  }
+  current_size_ = new_size;
 }
 
 template <typename Element>
 inline void RepeatedField<Element>::MoveArray(
-  Element* to, Element* from, int array_size) {
+    Element to[], Element from[], int array_size) {
   CopyArray(to, from, array_size);
 }
 
 template <typename Element>
 inline void RepeatedField<Element>::CopyArray(
-  Element* to, const Element* from, int array_size) {
+    Element to[], const Element from[], int array_size) {
   internal::ElementCopier<Element>()(to, from, array_size);
 }
 
@@ -1295,13 +781,13 @@ namespace internal {
 
 template <typename Element, bool HasTrivialCopy>
 void ElementCopier<Element, HasTrivialCopy>::operator()(
-  Element* to, const Element* from, int array_size) {
+    Element to[], const Element from[], int array_size) {
   std::copy(from, from + array_size, to);
 }
 
 template <typename Element>
 struct ElementCopier<Element, true> {
-  void operator()(Element* to, const Element* from, int array_size) {
+  void operator()(Element to[], const Element from[], int array_size) {
     memcpy(to, from, array_size * sizeof(Element));
   }
 };
@@ -1314,59 +800,18 @@ struct ElementCopier<Element, true> {
 namespace internal {
 
 inline RepeatedPtrFieldBase::RepeatedPtrFieldBase()
-  : arena_(NULL),
-    current_size_(0),
-    total_size_(0),
-    rep_(NULL) {
-}
-
-inline RepeatedPtrFieldBase::RepeatedPtrFieldBase(::google::protobuf::Arena* arena)
-  : arena_(arena),
+  : elements_(NULL),
     current_size_(0),
-    total_size_(0),
-    rep_(NULL) {
+    allocated_size_(0),
+    total_size_(kInitialSize) {
 }
 
 template <typename TypeHandler>
 void RepeatedPtrFieldBase::Destroy() {
-  if (rep_ != NULL) {
-    for (int i = 0; i < rep_->allocated_size; i++) {
-      TypeHandler::Delete(cast<TypeHandler>(rep_->elements[i]), arena_);
-    }
-    if (arena_ == NULL) {
-      delete [] reinterpret_cast<char*>(rep_);
-    }
+  for (int i = 0; i < allocated_size_; i++) {
+    TypeHandler::Delete(cast<TypeHandler>(elements_[i]));
   }
-  rep_ = NULL;
-}
-
-template <typename TypeHandler>
-inline void RepeatedPtrFieldBase::Swap(RepeatedPtrFieldBase* other) {
-  if (other->GetArenaNoVirtual() == GetArenaNoVirtual()) {
-    InternalSwap(other);
-  } else {
-    SwapFallback<TypeHandler>(other);
-  }
-}
-
-template <typename TypeHandler>
-inline void RepeatedPtrFieldBase::SwapFallback(RepeatedPtrFieldBase* other) {
-  GOOGLE_DCHECK(other->GetArenaNoVirtual() != GetArenaNoVirtual());
-
-  // Copy semantics in this case. We try to improve efficiency by placing the
-  // temporary on |other|'s arena so that messages are copied cross-arena only
-  // once, not twice.
-  RepeatedPtrFieldBase temp(other->GetArenaNoVirtual());
-  temp.MergeFrom<TypeHandler>(*this);
-  this->Clear<TypeHandler>();
-  this->MergeFrom<TypeHandler>(*other);
-  other->Clear<TypeHandler>();
-  other->InternalSwap(&temp);
-  temp.Destroy<TypeHandler>();  // Frees rep_ if `other` had no arena.
-}
-
-inline bool RepeatedPtrFieldBase::empty() const {
-  return current_size_ == 0;
+  delete [] elements_;
 }
 
 inline int RepeatedPtrFieldBase::size() const {
@@ -1376,122 +821,54 @@ inline int RepeatedPtrFieldBase::size() const {
 template <typename TypeHandler>
 inline const typename TypeHandler::Type&
 RepeatedPtrFieldBase::Get(int index) const {
-  GOOGLE_DCHECK_GE(index, 0);
-  GOOGLE_DCHECK_LT(index, current_size_);
-  return *cast<TypeHandler>(rep_->elements[index]);
+  GOOGLE_DCHECK_LT(index, size());
+  return *cast<TypeHandler>(elements_[index]);
 }
 
 
 template <typename TypeHandler>
 inline typename TypeHandler::Type*
 RepeatedPtrFieldBase::Mutable(int index) {
-  GOOGLE_DCHECK_GE(index, 0);
-  GOOGLE_DCHECK_LT(index, current_size_);
-  return cast<TypeHandler>(rep_->elements[index]);
+  GOOGLE_DCHECK_LT(index, size());
+  return cast<TypeHandler>(elements_[index]);
 }
 
 template <typename TypeHandler>
-inline void RepeatedPtrFieldBase::Delete(int index) {
-  GOOGLE_DCHECK_GE(index, 0);
-  GOOGLE_DCHECK_LT(index, current_size_);
-  TypeHandler::Delete(cast<TypeHandler>(rep_->elements[index]), arena_);
-}
-
-template <typename TypeHandler>
-inline typename TypeHandler::Type* RepeatedPtrFieldBase::Add(
-    typename TypeHandler::Type* prototype) {
-  if (rep_ != NULL && current_size_ < rep_->allocated_size) {
-    return cast<TypeHandler>(rep_->elements[current_size_++]);
-  }
-  if (!rep_ || rep_->allocated_size == total_size_) {
-    Reserve(total_size_ + 1);
-  }
-  ++rep_->allocated_size;
-  typename TypeHandler::Type* result =
-      TypeHandler::NewFromPrototype(prototype, arena_);
-  rep_->elements[current_size_++] = result;
+inline typename TypeHandler::Type* RepeatedPtrFieldBase::Add() {
+  if (current_size_ < allocated_size_) {
+    return cast<TypeHandler>(elements_[current_size_++]);
+  }
+  if (allocated_size_ == total_size_) Reserve(total_size_ + 1);
+  ++allocated_size_;
+  typename TypeHandler::Type* result = TypeHandler::New();
+  elements_[current_size_++] = result;
   return result;
 }
 
 template <typename TypeHandler>
 inline void RepeatedPtrFieldBase::RemoveLast() {
   GOOGLE_DCHECK_GT(current_size_, 0);
-  TypeHandler::Clear(cast<TypeHandler>(rep_->elements[--current_size_]));
+  TypeHandler::Clear(cast<TypeHandler>(elements_[--current_size_]));
 }
 
 template <typename TypeHandler>
 void RepeatedPtrFieldBase::Clear() {
-  const int n = current_size_;
-  GOOGLE_DCHECK_GE(n, 0);
-  if (n > 0) {
-    void* const* elements = rep_->elements;
-    int i = 0;
-    do {
-      TypeHandler::Clear(cast<TypeHandler>(elements[i++]));
-    } while (i < n);
-    current_size_ = 0;
+  for (int i = 0; i < current_size_; i++) {
+    TypeHandler::Clear(cast<TypeHandler>(elements_[i]));
   }
+  current_size_ = 0;
 }
 
-// To avoid unnecessary code duplication and reduce binary size, we use a
-// layered approach to implementing MergeFrom(). The toplevel method is
-// templated, so we get a small thunk per concrete message type in the binary.
-// This calls a shared implementation with most of the logic, passing a function
-// pointer to another type-specific piece of code that calls the object-allocate
-// and merge handlers.
 template <typename TypeHandler>
 inline void RepeatedPtrFieldBase::MergeFrom(const RepeatedPtrFieldBase& other) {
-  GOOGLE_DCHECK_NE(&other, this);
-  if (other.current_size_ == 0) return;
-  MergeFromInternal(
-      other, &RepeatedPtrFieldBase::MergeFromInnerLoop<TypeHandler>);
-}
-
-inline void RepeatedPtrFieldBase::MergeFromInternal(
-    const RepeatedPtrFieldBase& other,
-    void (RepeatedPtrFieldBase::*inner_loop)(void**, void**, int, int)) {
-  // Note: wrapper has already guaranteed that other.rep_ != NULL here.
-  int other_size = other.current_size_;
-  void** other_elements = other.rep_->elements;
-  void** new_elements = InternalExtend(other_size);
-  int allocated_elems = rep_->allocated_size - current_size_;
-  (this->*inner_loop)(new_elements, other_elements,
-                      other_size, allocated_elems);
-  current_size_ += other_size;
-  if (rep_->allocated_size < current_size_) {
-    rep_->allocated_size = current_size_;
-  }
-}
-
-// Merges other_elems to our_elems.
-template<typename TypeHandler>
-void RepeatedPtrFieldBase::MergeFromInnerLoop(
-    void** our_elems, void** other_elems, int length, int already_allocated) {
-  // Split into two loops, over ranges [0, allocated) and [allocated, length),
-  // to avoid a branch within the loop.
-  for (int i = 0; i < already_allocated && i < length; i++) {
-    // Already allocated: use existing element.
-    typename TypeHandler::Type* other_elem =
-        reinterpret_cast<typename TypeHandler::Type*>(other_elems[i]);
-    typename TypeHandler::Type* new_elem =
-        reinterpret_cast<typename TypeHandler::Type*>(our_elems[i]);
-    TypeHandler::Merge(*other_elem, new_elem);
-  }
-  Arena* arena = GetArenaNoVirtual();
-  for (int i = already_allocated; i < length; i++) {
-    // Not allocated: alloc a new element first, then merge it.
-    typename TypeHandler::Type* other_elem =
-        reinterpret_cast<typename TypeHandler::Type*>(other_elems[i]);
-    typename TypeHandler::Type* new_elem =
-        TypeHandler::NewFromPrototype(other_elem, arena);
-    TypeHandler::Merge(*other_elem, new_elem);
-    our_elems[i] = new_elem;
+  Reserve(current_size_ + other.current_size_);
+  for (int i = 0; i < other.current_size_; i++) {
+    TypeHandler::Merge(other.template Get<TypeHandler>(i), Add<TypeHandler>());
   }
 }
 
 template <typename TypeHandler>
 inline void RepeatedPtrFieldBase::CopyFrom(const RepeatedPtrFieldBase& other) {
-  if (&other == this) return;
   RepeatedPtrFieldBase::Clear<TypeHandler>();
   RepeatedPtrFieldBase::MergeFrom<TypeHandler>(other);
 }
@@ -1501,18 +878,18 @@ inline int RepeatedPtrFieldBase::Capacity() const {
 }
 
 inline void* const* RepeatedPtrFieldBase::raw_data() const {
-  return rep_ ? rep_->elements : NULL;
+  return elements_;
 }
 
 inline void** RepeatedPtrFieldBase::raw_mutable_data() const {
-  return rep_ ? const_cast<void**>(rep_->elements) : NULL;
+  return elements_;
 }
 
 template <typename TypeHandler>
 inline typename TypeHandler::Type** RepeatedPtrFieldBase::mutable_data() {
   // TODO(kenton):  Breaks C++ aliasing rules.  We should probably remove this
   //   method entirely.
-  return reinterpret_cast<typename TypeHandler::Type**>(raw_mutable_data());
+  return reinterpret_cast<typename TypeHandler::Type**>(elements_);
 }
 
 template <typename TypeHandler>
@@ -1520,212 +897,88 @@ inline const typename TypeHandler::Type* const*
 RepeatedPtrFieldBase::data() const {
   // TODO(kenton):  Breaks C++ aliasing rules.  We should probably remove this
   //   method entirely.
-  return reinterpret_cast<const typename TypeHandler::Type* const*>(raw_data());
+  return reinterpret_cast<const typename TypeHandler::Type* const*>(elements_);
 }
 
 inline void RepeatedPtrFieldBase::SwapElements(int index1, int index2) {
-  using std::swap;  // enable ADL with fallback
-  swap(rep_->elements[index1], rep_->elements[index2]);
+  std::swap(elements_[index1], elements_[index2]);
 }
 
 template <typename TypeHandler>
 inline int RepeatedPtrFieldBase::SpaceUsedExcludingSelf() const {
-  int allocated_bytes = total_size_ * sizeof(void*);
-  if (rep_ != NULL) {
-    for (int i = 0; i < rep_->allocated_size; ++i) {
-      allocated_bytes += TypeHandler::SpaceUsed(
-          *cast<TypeHandler>(rep_->elements[i]));
-    }
-    allocated_bytes += kRepHeaderSize;
+  int allocated_bytes =
+      (elements_ != NULL) ? total_size_ * sizeof(elements_[0]) : 0;
+  for (int i = 0; i < allocated_size_; ++i) {
+    allocated_bytes += TypeHandler::SpaceUsed(*cast<TypeHandler>(elements_[i]));
   }
   return allocated_bytes;
 }
 
 template <typename TypeHandler>
 inline typename TypeHandler::Type* RepeatedPtrFieldBase::AddFromCleared() {
-  if (rep_ != NULL && current_size_ < rep_->allocated_size) {
-    return cast<TypeHandler>(rep_->elements[current_size_++]);
+  if (current_size_ < allocated_size_) {
+    return cast<TypeHandler>(elements_[current_size_++]);
   } else {
     return NULL;
   }
 }
 
-// AddAllocated version that implements arena-safe copying behavior.
-template <typename TypeHandler>
-void RepeatedPtrFieldBase::AddAllocatedInternal(
-    typename TypeHandler::Type* value,
-    google::protobuf::internal::true_type) {
-  Arena* element_arena = reinterpret_cast<Arena*>(
-      TypeHandler::GetMaybeArenaPointer(value));
-  Arena* arena = GetArenaNoVirtual();
-  if (arena == element_arena && rep_ &&
-      rep_->allocated_size < total_size_) {
-    // Fast path: underlying arena representation (tagged pointer) is equal to
-    // our arena pointer, and we can add to array without resizing it (at least
-    // one slot that is not allocated).
-    void** elems = rep_->elements;
-    if (current_size_ < rep_->allocated_size) {
-      // Make space at [current] by moving first allocated element to end of
-      // allocated list.
-      elems[rep_->allocated_size] = elems[current_size_];
-    }
-    elems[current_size_] = value;
-    current_size_ = current_size_ + 1;
-    rep_->allocated_size = rep_->allocated_size + 1;
-    return;
-  } else {
-    AddAllocatedSlowWithCopy<TypeHandler>(
-        value, TypeHandler::GetArena(value), arena);
-  }
-}
-
-// Slowpath handles all cases, copying if necessary.
-template<typename TypeHandler>
-void RepeatedPtrFieldBase::AddAllocatedSlowWithCopy(
-    // Pass value_arena and my_arena to avoid duplicate virtual call (value) or
-    // load (mine).
-    typename TypeHandler::Type* value, Arena* value_arena, Arena* my_arena) {
-  // Ensure that either the value is in the same arena, or if not, we do the
-  // appropriate thing: Own() it (if it's on heap and we're in an arena) or copy
-  // it to our arena/heap (otherwise).
-  if (my_arena != NULL && value_arena == NULL) {
-    my_arena->Own(value);
-  } else if (my_arena != value_arena) {
-    typename TypeHandler::Type* new_value =
-        TypeHandler::NewFromPrototype(value, my_arena);
-    TypeHandler::Merge(*value, new_value);
-    TypeHandler::Delete(value, value_arena);
-    value = new_value;
-  }
-
-  UnsafeArenaAddAllocated<TypeHandler>(value);
-}
-
-// AddAllocated version that does not implement arena-safe copying behavior.
 template <typename TypeHandler>
-void RepeatedPtrFieldBase::AddAllocatedInternal(
-    typename TypeHandler::Type* value,
-    google::protobuf::internal::false_type) {
-  if (rep_ &&  rep_->allocated_size < total_size_) {
-    // Fast path: underlying arena representation (tagged pointer) is equal to
-    // our arena pointer, and we can add to array without resizing it (at least
-    // one slot that is not allocated).
-    void** elems = rep_->elements;
-    if (current_size_ < rep_->allocated_size) {
-      // Make space at [current] by moving first allocated element to end of
-      // allocated list.
-      elems[rep_->allocated_size] = elems[current_size_];
-    }
-    elems[current_size_] = value;
-    current_size_ = current_size_ + 1;
-    ++rep_->allocated_size;
-    return;
-  } else {
-    UnsafeArenaAddAllocated<TypeHandler>(value);
-  }
-}
-
-template <typename TypeHandler>
-void RepeatedPtrFieldBase::UnsafeArenaAddAllocated(
+void RepeatedPtrFieldBase::AddAllocated(
     typename TypeHandler::Type* value) {
   // Make room for the new pointer.
-  if (!rep_ || current_size_ == total_size_) {
+  if (current_size_ == total_size_) {
     // The array is completely full with no cleared objects, so grow it.
     Reserve(total_size_ + 1);
-    ++rep_->allocated_size;
-  } else if (rep_->allocated_size == total_size_) {
+    ++allocated_size_;
+  } else if (allocated_size_ == total_size_) {
     // There is no more space in the pointer array because it contains some
     // cleared objects awaiting reuse.  We don't want to grow the array in this
     // case because otherwise a loop calling AddAllocated() followed by Clear()
     // would leak memory.
-    TypeHandler::Delete(
-        cast<TypeHandler>(rep_->elements[current_size_]), arena_);
-  } else if (current_size_ < rep_->allocated_size) {
+    TypeHandler::Delete(cast<TypeHandler>(elements_[current_size_]));
+  } else if (current_size_ < allocated_size_) {
     // We have some cleared objects.  We don't care about their order, so we
     // can just move the first one to the end to make space.
-    rep_->elements[rep_->allocated_size] = rep_->elements[current_size_];
-    ++rep_->allocated_size;
+    elements_[allocated_size_] = elements_[current_size_];
+    ++allocated_size_;
   } else {
     // There are no cleared objects.
-    ++rep_->allocated_size;
+    ++allocated_size_;
   }
 
-  rep_->elements[current_size_++] = value;
+  elements_[current_size_++] = value;
 }
 
-// ReleaseLast() for types that implement merge/copy behavior.
 template <typename TypeHandler>
-inline typename TypeHandler::Type*
-RepeatedPtrFieldBase::ReleaseLastInternal(google::protobuf::internal::true_type) {
-  // First, release an element.
-  typename TypeHandler::Type* result = UnsafeArenaReleaseLast<TypeHandler>();
-  // Now perform a copy if we're on an arena.
-  Arena* arena = GetArenaNoVirtual();
-  if (arena == NULL) {
-    return result;
-  } else {
-    typename TypeHandler::Type* new_result =
-        TypeHandler::NewFromPrototype(result, NULL);
-    TypeHandler::Merge(*result, new_result);
-    return new_result;
-  }
-}
-
-// ReleaseLast() for types that *do not* implement merge/copy behavior -- this
-// is the same as UnsafeArenaReleaseLast(). Note that we GOOGLE_DCHECK-fail if we're on
-// an arena, since the user really should implement the copy operation in this
-// case.
-template <typename TypeHandler>
-inline typename TypeHandler::Type*
-RepeatedPtrFieldBase::ReleaseLastInternal(google::protobuf::internal::false_type) {
-  GOOGLE_DCHECK(GetArenaNoVirtual() == NULL)
-      << "ReleaseLast() called on a RepeatedPtrField that is on an arena, "
-      << "with a type that does not implement MergeFrom. This is unsafe; "
-      << "please implement MergeFrom for your type.";
-  return UnsafeArenaReleaseLast<TypeHandler>();
-}
-
-template <typename TypeHandler>
-inline typename TypeHandler::Type*
-  RepeatedPtrFieldBase::UnsafeArenaReleaseLast() {
+inline typename TypeHandler::Type* RepeatedPtrFieldBase::ReleaseLast() {
   GOOGLE_DCHECK_GT(current_size_, 0);
   typename TypeHandler::Type* result =
-      cast<TypeHandler>(rep_->elements[--current_size_]);
-  --rep_->allocated_size;
-  if (current_size_ < rep_->allocated_size) {
+      cast<TypeHandler>(elements_[--current_size_]);
+  --allocated_size_;
+  if (current_size_ < allocated_size_) {
     // There are cleared elements on the end; replace the removed element
     // with the last allocated element.
-    rep_->elements[current_size_] = rep_->elements[rep_->allocated_size];
+    elements_[current_size_] = elements_[allocated_size_];
   }
   return result;
 }
 
 inline int RepeatedPtrFieldBase::ClearedCount() const {
-  return rep_ ? (rep_->allocated_size - current_size_) : 0;
+  return allocated_size_ - current_size_;
 }
 
 template <typename TypeHandler>
 inline void RepeatedPtrFieldBase::AddCleared(
     typename TypeHandler::Type* value) {
-  GOOGLE_DCHECK(GetArenaNoVirtual() == NULL)
-      << "AddCleared() can only be used on a RepeatedPtrField not on an arena.";
-  GOOGLE_DCHECK(TypeHandler::GetArena(value) == NULL)
-      << "AddCleared() can only accept values not on an arena.";
-  if (!rep_ || rep_->allocated_size == total_size_) {
-    Reserve(total_size_ + 1);
-  }
-  rep_->elements[rep_->allocated_size++] = value;
+  if (allocated_size_ == total_size_) Reserve(total_size_ + 1);
+  elements_[allocated_size_++] = value;
 }
 
 template <typename TypeHandler>
 inline typename TypeHandler::Type* RepeatedPtrFieldBase::ReleaseCleared() {
-  GOOGLE_DCHECK(GetArenaNoVirtual() == NULL)
-      << "ReleaseCleared() can only be used on a RepeatedPtrField not on "
-      << "an arena.";
-  GOOGLE_DCHECK(GetArenaNoVirtual() == NULL);
-  GOOGLE_DCHECK(rep_ != NULL);
-  GOOGLE_DCHECK_GT(rep_->allocated_size, current_size_);
-  return cast<TypeHandler>(rep_->elements[--rep_->allocated_size]);
+  GOOGLE_DCHECK_GT(allocated_size_, current_size_);
+  return cast<TypeHandler>(elements_[--allocated_size_]);
 }
 
 }  // namespace internal
@@ -1744,17 +997,11 @@ class RepeatedPtrField<string>::TypeHandler
 
 
 template <typename Element>
-inline RepeatedPtrField<Element>::RepeatedPtrField()
-  : RepeatedPtrFieldBase() {}
-
-template <typename Element>
-inline RepeatedPtrField<Element>::RepeatedPtrField(::google::protobuf::Arena* arena) :
-  RepeatedPtrFieldBase(arena) {}
+inline RepeatedPtrField<Element>::RepeatedPtrField() {}
 
 template <typename Element>
 inline RepeatedPtrField<Element>::RepeatedPtrField(
-    const RepeatedPtrField& other)
-  : RepeatedPtrFieldBase() {
+    const RepeatedPtrField& other) {
   CopyFrom(other);
 }
 
@@ -1762,10 +1009,6 @@ template <typename Element>
 template <typename Iter>
 inline RepeatedPtrField<Element>::RepeatedPtrField(
     Iter begin, const Iter& end) {
-  int reserve = internal::CalculateReserve(begin, end);
-  if (reserve != -1) {
-    Reserve(reserve);
-  }
   for (; begin != end; ++begin) {
     *Add() = *begin;
   }
@@ -1785,11 +1028,6 @@ inline RepeatedPtrField<Element>& RepeatedPtrField<Element>::operator=(
 }
 
 template <typename Element>
-inline bool RepeatedPtrField<Element>::empty() const {
-  return RepeatedPtrFieldBase::empty();
-}
-
-template <typename Element>
 inline int RepeatedPtrField<Element>::size() const {
   return RepeatedPtrFieldBase::size();
 }
@@ -1820,71 +1058,14 @@ inline void RepeatedPtrField<Element>::DeleteSubrange(int start, int num) {
   GOOGLE_DCHECK_GE(start, 0);
   GOOGLE_DCHECK_GE(num, 0);
   GOOGLE_DCHECK_LE(start + num, size());
-  for (int i = 0; i < num; ++i) {
-    RepeatedPtrFieldBase::Delete<TypeHandler>(start + i);
-  }
+  for (int i = 0; i < num; ++i)
+    delete RepeatedPtrFieldBase::Mutable<TypeHandler>(start + i);
   ExtractSubrange(start, num, NULL);
 }
 
 template <typename Element>
 inline void RepeatedPtrField<Element>::ExtractSubrange(
     int start, int num, Element** elements) {
-  typename internal::TypeImplementsMergeBehavior<
-      typename TypeHandler::Type>::type t;
-  ExtractSubrangeInternal(start, num, elements, t);
-}
-
-// ExtractSubrange() implementation for types that implement merge/copy
-// behavior.
-template <typename Element>
-inline void RepeatedPtrField<Element>::ExtractSubrangeInternal(
-    int start, int num, Element** elements, google::protobuf::internal::true_type) {
-  GOOGLE_DCHECK_GE(start, 0);
-  GOOGLE_DCHECK_GE(num, 0);
-  GOOGLE_DCHECK_LE(start + num, size());
-
-  if (num > 0) {
-    // Save the values of the removed elements if requested.
-    if (elements != NULL) {
-      if (GetArenaNoVirtual() != NULL) {
-        // If we're on an arena, we perform a copy for each element so that the
-        // returned elements are heap-allocated.
-        for (int i = 0; i < num; ++i) {
-          Element* element = RepeatedPtrFieldBase::
-              Mutable<TypeHandler>(i + start);
-          typename TypeHandler::Type* new_value =
-              TypeHandler::NewFromPrototype(element, NULL);
-          TypeHandler::Merge(*element, new_value);
-          elements[i] = new_value;
-        }
-      } else {
-        for (int i = 0; i < num; ++i) {
-          elements[i] = RepeatedPtrFieldBase::Mutable<TypeHandler>(i + start);
-        }
-      }
-    }
-    CloseGap(start, num);
-  }
-}
-
-// ExtractSubrange() implementation for types that do not implement merge/copy
-// behavior.
-template<typename Element>
-inline void RepeatedPtrField<Element>::ExtractSubrangeInternal(
-    int start, int num, Element** elements, google::protobuf::internal::false_type) {
-  // This case is identical to UnsafeArenaExtractSubrange(). However, since
-  // ExtractSubrange() must return heap-allocated objects by contract, and we
-  // cannot fulfill this contract if we are an on arena, we must GOOGLE_DCHECK() that
-  // we are not on an arena.
-  GOOGLE_DCHECK(GetArenaNoVirtual() == NULL)
-      << "ExtractSubrange() when arena is non-NULL is only supported when "
-      << "the Element type supplies a MergeFrom() operation to make copies.";
-  UnsafeArenaExtractSubrange(start, num, elements);
-}
-
-template <typename Element>
-inline void RepeatedPtrField<Element>::UnsafeArenaExtractSubrange(
-    int start, int num, Element** elements) {
   GOOGLE_DCHECK_GE(start, 0);
   GOOGLE_DCHECK_GE(num, 0);
   GOOGLE_DCHECK_LE(start + num, size());
@@ -1892,9 +1073,8 @@ inline void RepeatedPtrField<Element>::UnsafeArenaExtractSubrange(
   if (num > 0) {
     // Save the values of the removed elements if requested.
     if (elements != NULL) {
-      for (int i = 0; i < num; ++i) {
+      for (int i = 0; i < num; ++i)
         elements[i] = RepeatedPtrFieldBase::Mutable<TypeHandler>(i + start);
-      }
     }
     CloseGap(start, num);
   }
@@ -1918,21 +1098,6 @@ inline void RepeatedPtrField<Element>::CopyFrom(
 }
 
 template <typename Element>
-inline typename RepeatedPtrField<Element>::iterator
-RepeatedPtrField<Element>::erase(const_iterator position) {
-  return erase(position, position + 1);
-}
-
-template <typename Element>
-inline typename RepeatedPtrField<Element>::iterator
-RepeatedPtrField<Element>::erase(const_iterator first, const_iterator last) {
-  size_type pos_offset = std::distance(cbegin(), first);
-  size_type last_offset = std::distance(cbegin(), last);
-  DeleteSubrange(pos_offset, last_offset - pos_offset);
-  return begin() + pos_offset;
-}
-
-template <typename Element>
 inline Element** RepeatedPtrField<Element>::mutable_data() {
   return RepeatedPtrFieldBase::mutable_data<TypeHandler>();
 }
@@ -1943,32 +1108,16 @@ inline const Element* const* RepeatedPtrField<Element>::data() const {
 }
 
 template <typename Element>
-inline void RepeatedPtrField<Element>::Swap(RepeatedPtrField* other) {
-  if (this == other)
-    return;
-  RepeatedPtrFieldBase::Swap<TypeHandler>(other);
-}
-
-template <typename Element>
-inline void RepeatedPtrField<Element>::UnsafeArenaSwap(
-    RepeatedPtrField* other) {
-  GOOGLE_DCHECK(GetArenaNoVirtual() == other->GetArenaNoVirtual());
-  if (this == other)
-      return;
-  RepeatedPtrFieldBase::InternalSwap(other);
+void RepeatedPtrField<Element>::Swap(RepeatedPtrField* other) {
+  RepeatedPtrFieldBase::Swap(other);
 }
 
 template <typename Element>
-inline void RepeatedPtrField<Element>::SwapElements(int index1, int index2) {
+void RepeatedPtrField<Element>::SwapElements(int index1, int index2) {
   RepeatedPtrFieldBase::SwapElements(index1, index2);
 }
 
 template <typename Element>
-inline Arena* RepeatedPtrField<Element>::GetArenaNoVirtual() const {
-  return RepeatedPtrFieldBase::GetArenaNoVirtual();
-}
-
-template <typename Element>
 inline int RepeatedPtrField<Element>::SpaceUsedExcludingSelf() const {
   return RepeatedPtrFieldBase::SpaceUsedExcludingSelf<TypeHandler>();
 }
@@ -1979,19 +1128,10 @@ inline void RepeatedPtrField<Element>::AddAllocated(Element* value) {
 }
 
 template <typename Element>
-inline void RepeatedPtrField<Element>::UnsafeArenaAddAllocated(Element* value) {
-  RepeatedPtrFieldBase::UnsafeArenaAddAllocated<TypeHandler>(value);
-}
-
-template <typename Element>
 inline Element* RepeatedPtrField<Element>::ReleaseLast() {
   return RepeatedPtrFieldBase::ReleaseLast<TypeHandler>();
 }
 
-template <typename Element>
-inline Element* RepeatedPtrField<Element>::UnsafeArenaReleaseLast() {
-  return RepeatedPtrFieldBase::UnsafeArenaReleaseLast<TypeHandler>();
-}
 
 template <typename Element>
 inline int RepeatedPtrField<Element>::ClearedCount() const {
@@ -2042,10 +1182,6 @@ class RepeatedPtrIterator
   typedef std::iterator<
           std::random_access_iterator_tag, Element> superclass;
 
-  // Shadow the value_type in std::iterator<> because const_iterator::value_type
-  // needs to be T, not const T.
-  typedef typename remove_const<Element>::type value_type;
-
   // Let the compiler know that these are type names, so we don't have to
   // write "typename" in front of them everywhere.
   typedef typename superclass::reference reference;
@@ -2091,11 +1227,11 @@ class RepeatedPtrIterator
     it_ += d;
     return *this;
   }
-  friend iterator operator+(iterator it, const difference_type d) {
+  friend iterator operator+(iterator it, difference_type d) {
     it += d;
     return it;
   }
-  friend iterator operator+(const difference_type d, iterator it) {
+  friend iterator operator+(difference_type d, iterator it) {
     it += d;
     return it;
   }
@@ -2137,10 +1273,6 @@ class RepeatedPtrOverPtrsIterator
   typedef std::iterator<
           std::random_access_iterator_tag, Element*> superclass;
 
-  // Shadow the value_type in std::iterator<> because const_iterator::value_type
-  // needs to be T, not const T.
-  typedef typename remove_const<Element*>::type value_type;
-
   // Let the compiler know that these are type names, so we don't have to
   // write "typename" in front of them everywhere.
   typedef typename superclass::reference reference;
@@ -2206,12 +1338,6 @@ class RepeatedPtrOverPtrsIterator
   VoidPtr* it_;
 };
 
-void RepeatedPtrFieldBase::InternalSwap(RepeatedPtrFieldBase* other) {
-  std::swap(rep_, other->rep_);
-  std::swap(current_size_, other->current_size_);
-  std::swap(total_size_, other->total_size_);
-}
-
 }  // namespace internal
 
 template <typename Element>
@@ -2225,11 +1351,6 @@ RepeatedPtrField<Element>::begin() const {
   return iterator(raw_data());
 }
 template <typename Element>
-inline typename RepeatedPtrField<Element>::const_iterator
-RepeatedPtrField<Element>::cbegin() const {
-  return begin();
-}
-template <typename Element>
 inline typename RepeatedPtrField<Element>::iterator
 RepeatedPtrField<Element>::end() {
   return iterator(raw_data() + size());
@@ -2239,11 +1360,6 @@ inline typename RepeatedPtrField<Element>::const_iterator
 RepeatedPtrField<Element>::end() const {
   return iterator(raw_data() + size());
 }
-template <typename Element>
-inline typename RepeatedPtrField<Element>::const_iterator
-RepeatedPtrField<Element>::cend() const {
-  return end();
-}
 
 template <typename Element>
 inline typename RepeatedPtrField<Element>::pointer_iterator
@@ -2270,7 +1386,7 @@ RepeatedPtrField<Element>::pointer_end() const {
 
 // Iterators and helper functions that follow the spirit of the STL
 // std::back_insert_iterator and std::back_inserter but are tailor-made
-// for RepeatedField and RepeatedPtrField. Typical usage would be:
+// for RepeatedField and RepatedPtrField. Typical usage would be:
 //
 //   std::copy(some_sequence.begin(), some_sequence.end(),
 //             google::protobuf::RepeatedFieldBackInserter(proto.mutable_sequence()));