diff --git a/objectivec/GPBDescriptor_PackagePrivate.h b/objectivec/GPBDescriptor_PackagePrivate.h
new file mode 100644
index 0000000..7987d92
--- /dev/null
+++ b/objectivec/GPBDescriptor_PackagePrivate.h
@@ -0,0 +1,318 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// This header is private to the ProtobolBuffers library and must NOT be
+// included by any sources outside this library. The contents of this file are
+// subject to change at any time without notice.
+
+#import "GPBDescriptor.h"
+#import "GPBWireFormat.h"
+
+// Describes attributes of the field.
+typedef NS_OPTIONS(uint32_t, GPBFieldFlags) {
+  // These map to standard protobuf concepts.
+  GPBFieldRequired        = 1 << 0,
+  GPBFieldRepeated        = 1 << 1,
+  GPBFieldPacked          = 1 << 2,
+  GPBFieldOptional        = 1 << 3,
+  GPBFieldHasDefaultValue = 1 << 4,
+
+  // These are not standard protobuf concepts, they are specific to the
+  // Objective C runtime.
+
+  // These bits are used to mark the field as a map and what the key
+  // type is.
+  GPBFieldMapKeyMask     = 0xF << 8,
+  GPBFieldMapKeyInt32    =  1 << 8,
+  GPBFieldMapKeyInt64    =  2 << 8,
+  GPBFieldMapKeyUInt32   =  3 << 8,
+  GPBFieldMapKeyUInt64   =  4 << 8,
+  GPBFieldMapKeySInt32   =  5 << 8,
+  GPBFieldMapKeySInt64   =  6 << 8,
+  GPBFieldMapKeyFixed32  =  7 << 8,
+  GPBFieldMapKeyFixed64  =  8 << 8,
+  GPBFieldMapKeySFixed32 =  9 << 8,
+  GPBFieldMapKeySFixed64 = 10 << 8,
+  GPBFieldMapKeyBool     = 11 << 8,
+  GPBFieldMapKeyString   = 12 << 8,
+
+  // Indicates the field needs custom handling for the TextFormat name, if not
+  // set, the name can be derived from the ObjC name.
+  GPBFieldTextFormatNameCustom = 1 << 16,
+  // Indicates the field has an enum descriptor.
+  GPBFieldHasEnumDescriptor = 1 << 17,
+};
+
+// Describes a single field in a protobuf as it is represented as an ivar.
+typedef struct GPBMessageFieldDescription {
+  // Name of ivar.
+  const char *name;
+  // The field number for the ivar.
+  uint32_t number;
+  // The index (in bits) into _has_storage_.
+  //   > 0: the bit to use for a value being set.
+  //   = 0: no storage used.
+  //   < 0: in a oneOf, use a full int32 to record the field active.
+  int32_t hasIndex;
+  // Field flags. Use accessor functions below.
+  GPBFieldFlags flags;
+  // Data type of the ivar.
+  GPBDataType dataType;
+  // Offset of the variable into it's structure struct.
+  size_t offset;
+  // FieldOptions protobuf, serialized as string.
+  const char *fieldOptions;
+
+  GPBGenericValue defaultValue;  // Default value for the ivar.
+  union {
+    const char *className;  // Name for message class.
+    // For enums only: If EnumDescriptors are compiled in, it will be that,
+    // otherwise it will be the verifier.
+    GPBEnumDescriptorFunc enumDescFunc;
+    GPBEnumValidationFunc enumVerifier;
+  } dataTypeSpecific;
+} GPBMessageFieldDescription;
+
+// Describes a oneof.
+typedef struct GPBMessageOneofDescription {
+  // Name of this enum oneof.
+  const char *name;
+  // The index of this oneof in the has_storage.
+  int32_t index;
+} GPBMessageOneofDescription;
+
+// Describes an enum type defined in a .proto file.
+typedef struct GPBMessageEnumDescription {
+  GPBEnumDescriptorFunc enumDescriptorFunc;
+} GPBMessageEnumDescription;
+
+// Describes an individual enum constant of a particular type.
+typedef struct GPBMessageEnumValueDescription {
+  // Name of this enum constant.
+  const char *name;
+  // Numeric value of this enum constant.
+  int32_t number;
+} GPBMessageEnumValueDescription;
+
+// Describes attributes of the extension.
+typedef NS_OPTIONS(uint32_t, GPBExtensionOptions) {
+  // These map to standard protobuf concepts.
+  GPBExtensionRepeated      = 1 << 0,
+  GPBExtensionPacked        = 1 << 1,
+  GPBExtensionSetWireFormat = 1 << 2,
+};
+
+// An extension
+typedef struct GPBExtensionDescription {
+  const char *singletonName;
+  GPBDataType dataType;
+  const char *extendedClass;
+  int32_t fieldNumber;
+  GPBGenericValue defaultValue;
+  const char *messageOrGroupClassName;
+  GPBExtensionOptions options;
+  GPBEnumDescriptorFunc enumDescriptorFunc;
+} GPBExtensionDescription;
+
+@interface GPBDescriptor () {
+ @package
+  NSArray *fields_;
+  NSArray *oneofs_;
+  size_t storageSize_;
+}
+
+// fieldDescriptions, enumDescriptions, rangeDescriptions, and
+// extraTextFormatInfo have to be long lived, they are held as raw pointers.
++ (instancetype)
+    allocDescriptorForClass:(Class)messageClass
+                  rootClass:(Class)rootClass
+                       file:(GPBFileDescriptor *)file
+                     fields:(GPBMessageFieldDescription *)fieldDescriptions
+                 fieldCount:(NSUInteger)fieldCount
+                     oneofs:(GPBMessageOneofDescription *)oneofDescriptions
+                 oneofCount:(NSUInteger)oneofCount
+                      enums:(GPBMessageEnumDescription *)enumDescriptions
+                  enumCount:(NSUInteger)enumCount
+                     ranges:(const GPBExtensionRange *)ranges
+                 rangeCount:(NSUInteger)rangeCount
+                storageSize:(size_t)storageSize
+                 wireFormat:(BOOL)wireFormat;
++ (instancetype)
+    allocDescriptorForClass:(Class)messageClass
+                  rootClass:(Class)rootClass
+                       file:(GPBFileDescriptor *)file
+                     fields:(GPBMessageFieldDescription *)fieldDescriptions
+                 fieldCount:(NSUInteger)fieldCount
+                     oneofs:(GPBMessageOneofDescription *)oneofDescriptions
+                 oneofCount:(NSUInteger)oneofCount
+                      enums:(GPBMessageEnumDescription *)enumDescriptions
+                  enumCount:(NSUInteger)enumCount
+                     ranges:(const GPBExtensionRange *)ranges
+                 rangeCount:(NSUInteger)rangeCount
+                storageSize:(size_t)storageSize
+                 wireFormat:(BOOL)wireFormat
+        extraTextFormatInfo:(const char *)extraTextFormatInfo;
+
+- (instancetype)initWithClass:(Class)messageClass
+                         file:(GPBFileDescriptor *)file
+                       fields:(NSArray *)fields
+                       oneofs:(NSArray *)oneofs
+                        enums:(NSArray *)enums
+              extensionRanges:(const GPBExtensionRange *)ranges
+         extensionRangesCount:(NSUInteger)rangeCount
+                  storageSize:(size_t)storage
+                   wireFormat:(BOOL)wireFormat;
+
+@end
+
+@interface GPBFileDescriptor ()
+- (instancetype)initWithPackage:(NSString *)package
+                         syntax:(GPBFileSyntax)syntax;
+@end
+
+@interface GPBOneofDescriptor () {
+ @package
+  GPBMessageOneofDescription *oneofDescription_;
+  NSArray *fields_;
+
+  SEL caseSel_;
+}
+- (instancetype)initWithOneofDescription:
+                    (GPBMessageOneofDescription *)oneofDescription
+                                  fields:(NSArray *)fields;
+@end
+
+@interface GPBFieldDescriptor () {
+ @package
+  GPBMessageFieldDescription *description_;
+  GPB_UNSAFE_UNRETAINED GPBOneofDescriptor *containingOneof_;
+
+  SEL getSel_;
+  SEL setSel_;
+  SEL hasOrCountSel_;  // *Count for map<>/repeated fields, has* otherwise.
+  SEL setHasSel_;
+}
+
+// Single initializer
+// description has to be long lived, it is held as a raw pointer.
+- (instancetype)initWithFieldDescription:
+                    (GPBMessageFieldDescription *)description
+                               rootClass:(Class)rootClass
+                                  syntax:(GPBFileSyntax)syntax;
+@end
+
+@interface GPBEnumDescriptor ()
+// valueDescriptions and extraTextFormatInfo have to be long lived, they are
+// held as raw pointers.
++ (instancetype)
+    allocDescriptorForName:(NSString *)name
+                    values:(GPBMessageEnumValueDescription *)valueDescriptions
+                valueCount:(NSUInteger)valueCount
+              enumVerifier:(GPBEnumValidationFunc)enumVerifier;
++ (instancetype)
+    allocDescriptorForName:(NSString *)name
+                    values:(GPBMessageEnumValueDescription *)valueDescriptions
+                valueCount:(NSUInteger)valueCount
+              enumVerifier:(GPBEnumValidationFunc)enumVerifier
+       extraTextFormatInfo:(const char *)extraTextFormatInfo;
+
+- (instancetype)initWithName:(NSString *)name
+                      values:(GPBMessageEnumValueDescription *)valueDescriptions
+                  valueCount:(NSUInteger)valueCount
+                enumVerifier:(GPBEnumValidationFunc)enumVerifier;
+@end
+
+@interface GPBExtensionDescriptor () {
+ @package
+  GPBExtensionDescription *description_;
+}
+@property(nonatomic, readonly) GPBWireFormat wireType;
+
+// For repeated extensions, alternateWireType is the wireType with the opposite
+// value for the packable property.  i.e. - if the extension was marked packed
+// it would be the wire type for unpacked; if the extension was marked unpacked,
+// it would be the wire type for packed.
+@property(nonatomic, readonly) GPBWireFormat alternateWireType;
+
+// description has to be long lived, it is held as a raw pointer.
+- (instancetype)initWithExtensionDescription:
+    (GPBExtensionDescription *)description;
+- (NSComparisonResult)compareByFieldNumber:(GPBExtensionDescriptor *)other;
+@end
+
+CF_EXTERN_C_BEGIN
+
+GPB_INLINE BOOL GPBFieldIsMapOrArray(GPBFieldDescriptor *field) {
+  return (field->description_->flags &
+          (GPBFieldRepeated | GPBFieldMapKeyMask)) != 0;
+}
+
+GPB_INLINE GPBDataType GPBGetFieldDataType(GPBFieldDescriptor *field) {
+  return field->description_->dataType;
+}
+
+GPB_INLINE int32_t GPBFieldHasIndex(GPBFieldDescriptor *field) {
+  return field->description_->hasIndex;
+}
+
+GPB_INLINE uint32_t GPBFieldNumber(GPBFieldDescriptor *field) {
+  return field->description_->number;
+}
+
+uint32_t GPBFieldTag(GPBFieldDescriptor *self);
+
+// For repeated fields, alternateWireType is the wireType with the opposite
+// value for the packable property.  i.e. - if the field was marked packed it
+// would be the wire type for unpacked; if the field was marked unpacked, it
+// would be the wire type for packed.
+uint32_t GPBFieldAlternateTag(GPBFieldDescriptor *self);
+
+GPB_INLINE BOOL GPBPreserveUnknownFields(GPBFileSyntax syntax) {
+  return syntax != GPBFileSyntaxProto3;
+}
+
+GPB_INLINE BOOL GPBHasPreservingUnknownEnumSemantics(GPBFileSyntax syntax) {
+  return syntax == GPBFileSyntaxProto3;
+}
+
+GPB_INLINE BOOL GPBExtensionIsRepeated(GPBExtensionDescription *description) {
+  return (description->options & GPBExtensionRepeated) != 0;
+}
+
+GPB_INLINE BOOL GPBExtensionIsPacked(GPBExtensionDescription *description) {
+  return (description->options & GPBExtensionPacked) != 0;
+}
+
+GPB_INLINE BOOL GPBExtensionIsWireFormat(GPBExtensionDescription *description) {
+  return (description->options & GPBExtensionSetWireFormat) != 0;
+}
+
+
+CF_EXTERN_C_END