diff --git a/compiler/cpp/CMakeLists.txt b/compiler/cpp/CMakeLists.txt
index 01e229d..bc6591c 100644
--- a/compiler/cpp/CMakeLists.txt
+++ b/compiler/cpp/CMakeLists.txt
@@ -56,6 +56,7 @@
     src/main.h
     src/platform.h
     src/md5.h
+    src/audit/t_audit.cpp
     src/parse/t_doc.h
     src/parse/t_type.h
     src/parse/t_base_type.h
diff --git a/compiler/cpp/Makefile.am b/compiler/cpp/Makefile.am
index 559a839..f5514d9 100644
--- a/compiler/cpp/Makefile.am
+++ b/compiler/cpp/Makefile.am
@@ -40,6 +40,7 @@
                  src/platform.h \
                  src/logging.h \
                  src/md5.h \
+                 src/audit/t_audit.cpp \
                  src/parse/t_doc.h \
                  src/parse/t_type.h \
                  src/parse/t_base_type.h \
diff --git a/compiler/cpp/src/audit/readme.txt b/compiler/cpp/src/audit/readme.txt
new file mode 100644
index 0000000..f1c53e3
--- /dev/null
+++ b/compiler/cpp/src/audit/readme.txt
@@ -0,0 +1,32 @@
+Typical usage:
+    thrift.exe --audit <oldFile> <newFile>
+Example run:
+    > thrift.exe --audit test.thrift break1.thrift
+    [Thrift Audit Failure:break1.thrift] New Thrift File has missing function base_function3
+    [Thrift Audit Warning:break1.thrift] Constant const3 has different value
+
+Problems that the audit tool can catch:
+Errors
+    Removing an enum value
+    Changing the type of a struct field
+    Changing the required-ness of a struct field
+    Removing a struct field
+    Adding a required struct field
+    Adding a struct field 'in the middle'.  This usually indicates an old ID has been recycled
+    Struct removed
+    Oneway-ness change
+    Return type change
+    Missing function
+    Missing service
+    Change in service inheritance
+Warnings
+    Removing a language namespace declaration
+    Changing a namespace
+    Changing an enum value's name
+    Removing an enum class
+    Default value changed
+    Struct field name change
+    Removed constant
+    Type of constant changed
+    Value of constant changed
+    
\ No newline at end of file
diff --git a/compiler/cpp/src/audit/t_audit.cpp b/compiler/cpp/src/audit/t_audit.cpp
new file mode 100644
index 0000000..afcbd5e
--- /dev/null
+++ b/compiler/cpp/src/audit/t_audit.cpp
@@ -0,0 +1,466 @@
+
+#include <cassert>
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <time.h>
+#include <string>
+#include <algorithm>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <errno.h>
+#include <limits.h>
+
+// Careful: must include globals first for extern definitions
+#include "globals.h"
+
+#include "parse/t_program.h"
+#include "parse/t_scope.h"
+#include "parse/t_const.h"
+#include "parse/t_field.h"
+
+#include "version.h"
+
+#include "t_audit.h"
+
+extern int g_warn;
+extern std::string g_curpath;
+extern bool g_return_failure;
+
+void thrift_audit_warning(int level, const char* fmt, ...) {
+   if (g_warn < level) {
+      return;
+   }
+   va_list args;
+   printf("[Thrift Audit Warning:%s] ", g_curpath.c_str());
+   va_start(args, fmt);
+   vprintf(fmt, args);
+   va_end(args);
+   printf("\n");
+}
+
+void thrift_audit_failure(const char* fmt, ...) {
+  va_list args;
+  fprintf(stderr, "[Thrift Audit Failure:%s] ", g_curpath.c_str());
+  va_start(args, fmt);
+  vfprintf(stderr, fmt, args);
+  va_end(args);
+  fprintf(stderr, "\n");
+  g_return_failure = true;
+}
+
+void compare_namespace(t_program* newProgram, t_program* oldProgram)
+{
+   const std::map<std::string, std::string>& newNamespaceMap = newProgram->get_all_namespaces();
+   const std::map<std::string, std::string>& oldNamespaceMap = oldProgram->get_all_namespaces();
+
+   for(std::map<std::string, std::string>::const_iterator oldNamespaceMapIt = oldNamespaceMap.begin();
+         oldNamespaceMapIt != oldNamespaceMap.end();
+         oldNamespaceMapIt++)
+   {
+      std::map<std::string, std::string>::const_iterator newNamespaceMapIt = newNamespaceMap.find(oldNamespaceMapIt->first);
+      if(newNamespaceMapIt == newNamespaceMap.end())
+      {
+         thrift_audit_warning(1, "Language %s not found in new thrift file\n", (oldNamespaceMapIt->first).c_str());
+      }
+      else if((newNamespaceMapIt->second) != oldNamespaceMapIt->second)
+      {
+         thrift_audit_warning(1, "Namespace %s changed in new thrift file\n", (oldNamespaceMapIt->second).c_str());
+      }
+   }
+}
+
+void compare_enum_values(t_enum* newEnum,t_enum* oldEnum)
+{
+   const std::vector<t_enum_value*>& oldEnumValues = oldEnum->get_constants();
+   for(std::vector<t_enum_value*>::const_iterator oldEnumValuesIt = oldEnumValues.begin();
+         oldEnumValuesIt != oldEnumValues.end();
+         oldEnumValuesIt++)
+   {
+      int enumValue = (*oldEnumValuesIt)->get_value();
+      t_enum_value* newEnumValue = newEnum->get_constant_by_value(enumValue);
+      if(newEnumValue != NULL)
+      {
+         std::string enumName = (*oldEnumValuesIt)->get_name();
+         if(enumName != newEnumValue->get_name())
+         {
+            thrift_audit_warning(1, "Name of the value %d changed in enum %s\n", enumValue, oldEnum->get_name().c_str());
+         }      
+      }
+      else
+      {
+         thrift_audit_failure("Enum value %d missing in %s\n", enumValue, oldEnum->get_name().c_str());
+      }
+
+   }
+}
+
+void compare_enums(const std::vector<t_enum*>& newEnumList, const std::vector<t_enum*>& oldEnumList)
+{
+   std::map<std::string,t_enum*> newEnumMap;
+   std::vector<t_enum*>::const_iterator newEnumIt;
+   for(newEnumIt = newEnumList.begin(); newEnumIt != newEnumList.end(); newEnumIt++)
+   {
+      newEnumMap[(*newEnumIt)->get_name()] = *newEnumIt;
+   }
+   std::vector<t_enum*>::const_iterator oldEnumIt;
+   for(oldEnumIt = oldEnumList.begin(); oldEnumIt != oldEnumList.end(); oldEnumIt++)
+   {
+      std::map<std::string,t_enum*>::iterator newEnumMapIt;
+      newEnumMapIt = newEnumMap.find((*oldEnumIt)->get_name());
+
+      if(newEnumMapIt == newEnumMap.end())
+      {
+         thrift_audit_warning(1, "Enum %s not found in new thrift file\n",(*oldEnumIt)->get_name().c_str());
+      }
+      else
+      {
+         compare_enum_values(newEnumMapIt->second, *oldEnumIt);
+      }
+   }
+}
+
+//This function returns 'true' if the two arguements are of same types.
+//Returns false if they are of different type
+bool compare_type(t_type* newType, t_type* oldType)
+{
+   //Comparing names of two types will work when the newType and oldType are basic types or structs or enums.
+   //However, when they are containers, get_name() returns empty for which we have to compare the type of 
+   //their elements as well.
+   if((newType->get_name()).empty() && (oldType->get_name()).empty())
+   {
+
+      if(newType->is_list() && oldType->is_list())
+      {
+         t_type* newElementType = ((t_list*)newType)->get_elem_type();
+         t_type* oldElementType = ((t_list*)oldType)->get_elem_type();
+         return compare_type(newElementType, oldElementType);
+      }
+      else if(newType->is_map() && oldType->is_map())
+      {
+         t_type* newKeyType = ((t_map*)newType)->get_key_type();
+         t_type* oldKeyType = ((t_map*)oldType)->get_key_type();
+
+         t_type* newValType = ((t_map*)newType)->get_val_type();
+         t_type* oldValType = ((t_map*)oldType)->get_val_type();
+
+         return (compare_type(newKeyType, oldKeyType) && compare_type(newValType, oldValType));
+      }
+      else if(newType->is_set() && oldType->is_set())
+      {
+         t_type* newElementType = ((t_set*)newType)->get_elem_type();
+         t_type* oldElementType = ((t_set*)oldType)->get_elem_type();
+         return compare_type(newElementType, oldElementType); 
+      }
+      else
+      {
+         return false;
+      }
+   }
+   else if(newType->get_name() == oldType->get_name())
+   {
+      return true;
+   }
+   else
+   {
+      return false;
+   }
+}
+
+bool compare_pair(std::pair<t_const_value*, t_const_value*> newMapPair, std::pair<t_const_value*, t_const_value*> oldMapPair)
+{
+   return compare_defaults(newMapPair.first, oldMapPair.first) && compare_defaults(newMapPair.second, oldMapPair.second);
+}   
+
+// This function returns 'true' if the default values are same. Returns false if they are different.
+bool compare_defaults(t_const_value* newStructDefault, t_const_value* oldStructDefault)
+{
+   if(newStructDefault == NULL && oldStructDefault == NULL) return true;
+   else if(newStructDefault == NULL && oldStructDefault != NULL) return false;
+   else if (newStructDefault != NULL && oldStructDefault == NULL) return false;
+
+   if(newStructDefault->get_type() != oldStructDefault->get_type())
+   {
+      return false;
+   }
+
+   switch(newStructDefault->get_type())
+   {
+      case t_const_value::CV_INTEGER:
+         return (newStructDefault->get_integer() == oldStructDefault->get_integer());
+      case t_const_value::CV_DOUBLE:
+         return (newStructDefault->get_double() == oldStructDefault->get_double());
+      case t_const_value::CV_STRING:
+         return (newStructDefault->get_string() == oldStructDefault->get_string());
+      case t_const_value::CV_LIST:
+         {
+            const std::vector<t_const_value*>& oldDefaultList = oldStructDefault->get_list();
+            const std::vector<t_const_value*>& newDefaultList = newStructDefault->get_list();
+            bool defaultValuesCompare = (oldDefaultList.size() == newDefaultList.size());
+
+            return defaultValuesCompare && std::equal(newDefaultList.begin(), newDefaultList.end(), oldDefaultList.begin(), compare_defaults);
+         }
+      case t_const_value::CV_MAP:
+         {
+            const std::map<t_const_value*, t_const_value*> newMap = newStructDefault->get_map();
+            const std::map<t_const_value*, t_const_value*> oldMap = oldStructDefault->get_map();
+
+            bool defaultValuesCompare = (oldMap.size() == newMap.size());
+
+            return defaultValuesCompare && std::equal(newMap.begin(), newMap.end(), oldMap.begin(), compare_pair);
+         }
+      case t_const_value::CV_IDENTIFIER:
+         return (newStructDefault->get_identifier() == oldStructDefault->get_identifier());
+      default:
+         return false;
+   }
+
+}
+
+void compare_struct_field(t_field* newField, t_field* oldField, std::string oldStructName)
+{
+   t_type* newFieldType = newField->get_type();
+   t_type* oldFieldType = oldField->get_type();
+   if(!compare_type(newFieldType, oldFieldType))
+   {
+      thrift_audit_failure("Struct Field Type Changed for Id = %d in %s \n", newField->get_key(), oldStructName.c_str());
+   }
+
+   // A Struct member can be optional if it is mentioned explicitly, or if it is assigned with default values.
+   bool newStructFieldOptional = (newField->get_req() != t_field::T_REQUIRED);
+   bool oldStructFieldOptional = (oldField->get_req() != t_field::T_REQUIRED);
+
+   if(newStructFieldOptional != oldStructFieldOptional)
+   {
+      thrift_audit_failure("Struct Field Requiredness Changed for Id = %d in %s \n", newField->get_key(), oldStructName.c_str());
+   }
+   if(newStructFieldOptional || oldStructFieldOptional)
+   {
+      if(!compare_defaults(newField->get_value(), oldField->get_value()))
+      {
+         thrift_audit_warning(1, "Default value changed for Id = %d in %s \n", newField->get_key(), oldStructName.c_str());
+      }
+   }
+
+   std::string fieldName = newField->get_name();
+   if(fieldName != oldField->get_name())
+   {
+      thrift_audit_warning(1, "Struct field name changed for Id = %d in %s\n", newField->get_key(), oldStructName.c_str());
+   }
+
+}
+
+void compare_single_struct(t_struct* newStruct, t_struct* oldStruct, const std::string& oldStructName = std::string())
+{
+   std::string structName = oldStructName.empty() ? oldStruct->get_name() : oldStructName;
+   const std::vector<t_field*>& oldStructMembersInIdOrder = oldStruct->get_sorted_members();
+   const std::vector<t_field*>& newStructMembersInIdOrder = newStruct->get_sorted_members();
+   std::vector<t_field*>::const_iterator oldStructMemberIt = oldStructMembersInIdOrder.begin();
+   std::vector<t_field*>::const_iterator newStructMemberIt = newStructMembersInIdOrder.begin();
+
+   // Since we have the struct members in their ID order, comparing their IDs can be done by traversing the two member
+   // lists together.  
+   while(!(oldStructMemberIt == oldStructMembersInIdOrder.end() && newStructMemberIt == newStructMembersInIdOrder.end()))
+   {
+      if(newStructMemberIt == newStructMembersInIdOrder.end() && oldStructMemberIt != oldStructMembersInIdOrder.end())
+      {
+         // A field ID has been removed from the end.
+         thrift_audit_failure("Struct Field removed for Id = %d in %s \n", (*oldStructMemberIt)->get_key(), structName.c_str());
+         oldStructMemberIt++;
+      }
+      else if(newStructMemberIt != newStructMembersInIdOrder.end() && oldStructMemberIt == oldStructMembersInIdOrder.end())
+      {
+         //New field ID has been added to the end.
+         if((*newStructMemberIt)->get_req() == t_field::T_REQUIRED)
+         {
+            thrift_audit_failure("Required Struct Field Added for Id = %d in %s \n", (*newStructMemberIt)->get_key(), structName.c_str());
+         }
+         newStructMemberIt++;
+      }
+      else if((*newStructMemberIt)->get_key() == (*oldStructMemberIt)->get_key())
+      {
+         //Field ID found in both structs. Compare field types, default values.
+         compare_struct_field(*newStructMemberIt, *oldStructMemberIt, structName);
+
+         newStructMemberIt++;
+         oldStructMemberIt++;
+      }
+      else if((*newStructMemberIt)->get_key() < (*oldStructMemberIt)->get_key())
+      {
+         //New Field Id is inserted in between
+         //Adding fields to struct is fine, but adding them in the middle is suspicious. Error!!
+         thrift_audit_failure("Struct field is added in the middle with Id = %d in %s\n",  (*newStructMemberIt)->get_key(),  structName.c_str());
+         newStructMemberIt++;
+      }
+      else if((*newStructMemberIt)->get_key() > (*oldStructMemberIt)->get_key())
+      {
+         //A field is deleted in newStruct.
+         thrift_audit_failure("Struct Field removed for Id = %d in %s \n",  (*oldStructMemberIt)->get_key(), structName.c_str());
+         oldStructMemberIt++;
+      }
+
+   }
+}
+
+void compare_structs(const std::vector<t_struct*>& newStructList, const std::vector<t_struct*>& oldStructList)
+{
+   std::map<std::string,t_struct*> newStructMap;
+   std::vector<t_struct*>::const_iterator newStructListIt;
+   for(newStructListIt = newStructList.begin(); newStructListIt != newStructList.end(); newStructListIt++)
+   {
+      newStructMap[(*newStructListIt)->get_name()] = *newStructListIt;
+   }
+
+   std::vector<t_struct*>::const_iterator oldStructListIt;
+   for(oldStructListIt = oldStructList.begin(); oldStructListIt != oldStructList.end(); oldStructListIt++)
+   {
+      std::map<std::string, t_struct*>::iterator newStructMapIt;
+      newStructMapIt = newStructMap.find((*oldStructListIt)->get_name());
+      if(newStructMapIt == newStructMap.end())
+      {
+         thrift_audit_failure("Struct %s not found in new thrift file\n", (*oldStructListIt)->get_name().c_str());
+      }
+      else
+      {
+         compare_single_struct(newStructMapIt->second, *oldStructListIt);
+      }
+   }
+
+}
+
+void compare_single_function(t_function* newFunction, t_function* oldFunction)
+{
+   t_type* newFunctionReturnType = newFunction->get_returntype();
+
+   if(newFunction->is_oneway() != oldFunction->is_oneway())
+   {
+      thrift_audit_failure("Oneway attribute changed for function %s\n",oldFunction->get_name().c_str());
+   }
+   if(!compare_type(newFunctionReturnType, oldFunction->get_returntype()))
+   {
+      thrift_audit_failure("Return type changed for function %s\n",oldFunction->get_name().c_str());
+   }
+
+   //Compare function arguments.
+   compare_single_struct(newFunction->get_arglist(), oldFunction->get_arglist());
+   std::string exceptionName = oldFunction->get_name();
+   exceptionName += "_exception";
+   compare_single_struct(newFunction->get_xceptions(), oldFunction->get_xceptions(), exceptionName);
+}
+
+void compare_functions(const std::vector<t_function*>& newFunctionList, const std::vector<t_function*>& oldFunctionList)
+{
+   std::map<std::string, t_function*> newFunctionMap;
+   std::map<std::string, t_function*>::iterator newFunctionMapIt;
+   for(std::vector<t_function*>::const_iterator newFunctionIt = newFunctionList.begin();
+         newFunctionIt != newFunctionList.end();
+         newFunctionIt++)
+   {
+      newFunctionMap[(*newFunctionIt)->get_name()] = *newFunctionIt;
+   }
+
+   for(std::vector<t_function*>::const_iterator oldFunctionIt = oldFunctionList.begin();
+         oldFunctionIt != oldFunctionList.end();
+         oldFunctionIt++)
+   {
+      newFunctionMapIt = newFunctionMap.find((*oldFunctionIt)->get_name());
+      if(newFunctionMapIt == newFunctionMap.end())
+      {
+         thrift_audit_failure("New Thrift File has missing function %s\n",(*oldFunctionIt)->get_name().c_str());
+         continue;
+      }
+      else
+      {
+         //Function is found in both thrift files. Compare return type and argument list
+         compare_single_function(newFunctionMapIt->second, *oldFunctionIt);
+      }
+   }
+
+}
+
+void compare_services(const std::vector<t_service*>& newServices, const std::vector<t_service*>& oldServices)
+{
+   std::vector<t_service*>::const_iterator oldServiceIt;
+
+   std::map<std::string, t_service*> newServiceMap;
+   for(std::vector<t_service*>::const_iterator newServiceIt = newServices.begin();
+         newServiceIt != newServices.end();
+         newServiceIt++)
+   {
+      newServiceMap[(*newServiceIt)->get_name()] = *newServiceIt;
+   }
+
+
+   for(oldServiceIt = oldServices.begin(); oldServiceIt != oldServices.end(); oldServiceIt++)
+   {
+      const std::string oldServiceName = (*oldServiceIt)->get_name();
+      std::map<std::string, t_service*>::iterator newServiceMapIt = newServiceMap.find(oldServiceName);
+
+      if(newServiceMapIt == newServiceMap.end())
+      {
+         thrift_audit_failure("New Thrift file is missing a service %s\n", oldServiceName.c_str());
+      }
+      else
+      {
+         t_service* oldServiceExtends = (*oldServiceIt)->get_extends();
+         t_service* newServiceExtends = (newServiceMapIt->second)->get_extends();
+
+         if(oldServiceExtends == NULL)
+         {
+            // It is fine to add extends. So if service in older thrift did not have any extends, we are fine.
+            // DO Nothing
+         }
+         else if(oldServiceExtends != NULL && newServiceExtends == NULL)
+         {
+            thrift_audit_failure("Change in Service inheritance for %s\n", oldServiceName.c_str());
+         }
+         else
+         {
+            std::string oldExtendsName = oldServiceExtends->get_name();
+            std::string newExtendsName = newServiceExtends->get_name();
+
+            if( newExtendsName != oldExtendsName)
+            {
+               thrift_audit_failure("Change in Service inheritance for %s\n", oldServiceName.c_str());
+            }
+         }
+
+         compare_functions((newServiceMapIt->second)->get_functions(), (*oldServiceIt)->get_functions());
+      }
+
+   }
+
+}
+
+void compare_consts(const std::vector<t_const*>& newConst, const std::vector<t_const*>& oldConst)
+{
+   std::vector<t_const*>::const_iterator newConstIt;
+   std::vector<t_const*>::const_iterator oldConstIt;
+
+   std::map<std::string, t_const*> newConstMap;
+
+   for(newConstIt = newConst.begin(); newConstIt != newConst.end(); newConstIt++)
+   {
+      newConstMap[(*newConstIt)->get_name()] = *newConstIt;
+   }
+
+   std::map<std::string, t_const*>::const_iterator newConstMapIt;
+   for(oldConstIt = oldConst.begin(); oldConstIt != oldConst.end(); oldConstIt++)
+   {
+      newConstMapIt = newConstMap.find((*oldConstIt)->get_name());
+      if(newConstMapIt == newConstMap.end())
+      {
+         thrift_audit_warning(1, "Constants Missing %s \n", ((*oldConstIt)->get_name()).c_str());
+      }
+      else if(!compare_type((newConstMapIt->second)->get_type(), (*oldConstIt)->get_type()))
+      {
+         thrift_audit_warning(1, "Constant %s is of different type \n", ((*oldConstIt)->get_name()).c_str());
+      }
+      else if(!compare_defaults((newConstMapIt->second)->get_value(), (*oldConstIt)->get_value()))
+      {
+         thrift_audit_warning(1, "Constant %s has different value\n", ((*oldConstIt)->get_name()).c_str());
+      }
+   }
+}
+
+
diff --git a/compiler/cpp/src/audit/t_audit.h b/compiler/cpp/src/audit/t_audit.h
new file mode 100644
index 0000000..fd0013a
--- /dev/null
+++ b/compiler/cpp/src/audit/t_audit.h
@@ -0,0 +1,11 @@
+#ifndef T_AUDIT_H
+#define T_AUDIT_H
+
+void compare_namespace(t_program* newProgram, t_program* oldProgram);
+void compare_enums(const std::vector<t_enum*>& newEnumList, const std::vector<t_enum*>& oldEnumList);
+bool compare_defaults(t_const_value* newStructDefault, t_const_value* oldStructDefault);
+void compare_structs(const std::vector<t_struct*>& newStructList, const std::vector<t_struct*>& oldStructList);
+void compare_services(const std::vector<t_service*>& newServices, const std::vector<t_service*>& oldServices);
+void compare_consts(const std::vector<t_const*>& newConst, const std::vector<t_const*>& oldConst);
+
+#endif
diff --git a/compiler/cpp/src/main.cc b/compiler/cpp/src/main.cc
index 97d523e..a337cc6 100644
--- a/compiler/cpp/src/main.cc
+++ b/compiler/cpp/src/main.cc
@@ -51,6 +51,7 @@
 #include "parse/t_program.h"
 #include "parse/t_scope.h"
 #include "generate/t_generator.h"
+#include "audit/t_audit.h"
 
 #include "version.h"
 
@@ -169,6 +170,17 @@
 bool gen_recurse = false;
 
 /**
+ * Flags to control thrift audit
+ */
+bool g_audit = false;
+
+/**
+ * Flag to control return status
+ */
+bool g_return_failure = false;
+bool g_audit_fatal = true;
+
+/**
  * Win32 doesn't have realpath, so use fallback implementation in that case,
  * otherwise this just calls through to realpath
  */
@@ -711,6 +723,13 @@
   fprintf(stderr, "                Keys and values are options passed to the generator.\n");
   fprintf(stderr, "                Many options will not require values.\n");
   fprintf(stderr, "\n");
+  fprintf(stderr, "Options related to audit operation\n");
+  fprintf(stderr, "   --audit OldFile   Old Thrift file to be audited with 'file'\n");
+  fprintf(stderr, "  -Iold dir    Add a directory to the list of directories\n");
+  fprintf(stderr, "                searched for include directives for old thrift file\n");
+  fprintf(stderr, "  -Inew dir    Add a directory to the list of directories\n");
+  fprintf(stderr, "                searched for include directives for new thrift file\n");
+  fprintf(stderr, "\n");
   fprintf(stderr, "Available generators (and options):\n");
 
   t_generator_registry::gen_map_t gen_map = t_generator_registry::get_generator_map();
@@ -1029,6 +1048,30 @@
   }
 }
 
+void audit(t_program* new_program, t_program* old_program, string new_thrift_include_path, string old_thrift_include_path)
+{
+  vector<string> temp_incl_searchpath = g_incl_searchpath;
+  if(!old_thrift_include_path.empty()) {
+    g_incl_searchpath.push_back(old_thrift_include_path);
+  }
+
+  parse(old_program, NULL);
+
+  g_incl_searchpath = temp_incl_searchpath;
+  if(!new_thrift_include_path.empty()) {
+    g_incl_searchpath.push_back(new_thrift_include_path);
+  }
+
+  parse(new_program, NULL);
+
+  compare_namespace(new_program, old_program);
+  compare_services(new_program->get_services(), old_program->get_services());
+  compare_enums(new_program->get_enums(), old_program->get_enums());
+  compare_structs(new_program->get_structs(), old_program->get_structs());
+  compare_structs(new_program->get_xceptions(), old_program->get_xceptions());
+  compare_consts(new_program->get_consts(), old_program->get_consts());
+}
+
 /**
  * Parse it up.. then spit it back out, in pretty much every language. Alright
  * not that many languages, but the cool ones that we care about.
@@ -1049,6 +1092,9 @@
   }
 
   vector<string> generator_strings;
+  string old_thrift_include_path;
+  string new_thrift_include_path;
+  string old_input_file;
 
   // Set the current path to a dummy value to make warning messages clearer.
   g_curpath = "arguments";
@@ -1118,6 +1164,35 @@
 #endif
         if (!check_is_directory(out_path.c_str()))
           return -1;
+      } else if (strcmp(arg, "-audit") == 0) {
+        g_audit = true;
+        arg = argv[++i];
+        if (arg == NULL) {
+          fprintf(stderr, "Missing old thrift file name for audit operation\n");
+          usage();
+        }
+        char old_thrift_file_rp[THRIFT_PATH_MAX];
+
+        if (saferealpath(arg, old_thrift_file_rp) == NULL) {
+          failure("Could not open input file with realpath: %s", arg);
+        }
+        old_input_file = string(old_thrift_file_rp);
+      } else if(strcmp(arg, "-audit-nofatal") == 0){
+        g_audit_fatal = false;
+      } else if (strcmp(arg, "-Iold") == 0) {
+        arg = argv[++i];
+        if (arg == NULL) {
+          fprintf(stderr, "Missing Include directory for old thrift file\n");
+          usage();
+        }
+        old_thrift_include_path = string(arg);
+      } else if (strcmp(arg, "-Inew") == 0) {
+        arg = argv[++i];
+        if(arg == NULL) {
+        fprintf(stderr, "Missing Include directory for new thrift file\n");
+        usage();
+        }
+        new_thrift_include_path = string(arg);
       } else {
         fprintf(stderr, "Unrecognized option: %s\n", arg);
         usage();
@@ -1139,41 +1214,6 @@
     exit(0);
   }
 
-  // You gotta generate something!
-  if (generator_strings.empty()) {
-    fprintf(stderr, "No output language(s) specified\n");
-    usage();
-  }
-
-  // Real-pathify it
-  char rp[THRIFT_PATH_MAX];
-  if (argv[i] == NULL) {
-    fprintf(stderr, "Missing file name\n");
-    usage();
-  }
-  if (saferealpath(argv[i], rp) == NULL) {
-    failure("Could not open input file with realpath: %s", argv[i]);
-  }
-  string input_file(rp);
-
-  // Instance of the global parse tree
-  t_program* program = new t_program(input_file);
-  if (out_path.size()) {
-    program->set_out_path(out_path, out_path_is_absolute);
-  }
-
-  // Compute the cpp include prefix.
-  // infer this from the filename passed in
-  string input_filename = argv[i];
-  string include_prefix;
-
-  string::size_type last_slash = string::npos;
-  if ((last_slash = input_filename.rfind("/")) != string::npos) {
-    include_prefix = input_filename.substr(0, last_slash);
-  }
-
-  program->set_include_prefix(include_prefix);
-
   // Initialize global types
   g_type_void = new t_base_type("void", t_base_type::TYPE_VOID);
   g_type_string = new t_base_type("string", t_base_type::TYPE_STRING);
@@ -1188,24 +1228,87 @@
   g_type_i64 = new t_base_type("i64", t_base_type::TYPE_I64);
   g_type_double = new t_base_type("double", t_base_type::TYPE_DOUBLE);
 
-  // Parse it!
-  parse(program, NULL);
+  if(g_audit)
+  {
+    // Audit operation
 
-  // The current path is not really relevant when we are doing generation.
-  // Reset the variable to make warning messages clearer.
-  g_curpath = "generation";
-  // Reset yylineno for the heck of it.  Use 1 instead of 0 because
-  // That is what shows up during argument parsing.
-  yylineno = 1;
+    if (old_input_file.empty()) {
+      fprintf(stderr, "Missing file name of old thrift file for audit\n");
+      usage();
+    }
 
-  // Generate it!
-  generate(program, generator_strings);
+    char new_thrift_file_rp[THRIFT_PATH_MAX];
+    if (argv[i] == NULL) {
+      fprintf(stderr, "Missing file name of new thrift file for audit\n");
+      usage();
+    }
+    if (saferealpath(argv[i], new_thrift_file_rp) == NULL) {
+      failure("Could not open input file with realpath: %s", argv[i]);
+    }
+    string new_input_file(new_thrift_file_rp);
+
+    t_program new_program(new_input_file);
+    t_program old_program(old_input_file);
+
+    audit(&new_program, &old_program, new_thrift_include_path, old_thrift_include_path);
+
+  } else {
+    // Generate options
+    
+    // You gotta generate something!
+    if (generator_strings.empty()) {
+      fprintf(stderr, "No output language(s) specified\n");
+      usage();
+    }
+
+    // Real-pathify it
+    char rp[THRIFT_PATH_MAX];
+    if (argv[i] == NULL) {
+      fprintf(stderr, "Missing file name\n");
+      usage();
+    }
+    if (saferealpath(argv[i], rp) == NULL) {
+      failure("Could not open input file with realpath: %s", argv[i]);
+    }
+    string input_file(rp);
+
+    // Instance of the global parse tree
+    t_program* program = new t_program(input_file);
+    if (out_path.size()) {
+      program->set_out_path(out_path, out_path_is_absolute);
+    }
+
+    // Compute the cpp include prefix.
+    // infer this from the filename passed in
+    string input_filename = argv[i];
+    string include_prefix;
+
+    string::size_type last_slash = string::npos;
+    if ((last_slash = input_filename.rfind("/")) != string::npos) {
+      include_prefix = input_filename.substr(0, last_slash);
+    }
+
+    program->set_include_prefix(include_prefix);
+
+    // Parse it!
+    parse(program, NULL);
+
+    // The current path is not really relevant when we are doing generation.
+    // Reset the variable to make warning messages clearer.
+    g_curpath = "generation";
+    // Reset yylineno for the heck of it.  Use 1 instead of 0 because
+    // That is what shows up during argument parsing.
+    yylineno = 1;
+
+    // Generate it!
+    generate(program, generator_strings);
+    delete program;
+  }
 
   // Clean up. Who am I kidding... this program probably orphans heap memory
   // all over the place, but who cares because it is about to exit and it is
   // all referenced and used by this wacky parse tree up until now anyways.
 
-  delete program;
   delete g_type_void;
   delete g_type_string;
   delete g_type_bool;
@@ -1216,5 +1319,9 @@
   delete g_type_double;
 
   // Finished
+  if (g_return_failure && g_audit_fatal) {
+    exit(2);
+  }
+  // Finished
   return 0;
 }
diff --git a/compiler/cpp/src/parse/t_program.h b/compiler/cpp/src/parse/t_program.h
index cfab691..556ee6c 100644
--- a/compiler/cpp/src/parse/t_program.h
+++ b/compiler/cpp/src/parse/t_program.h
@@ -321,6 +321,9 @@
     return std::string();
   }
 
+  const std::map<std::string, std::string>& get_all_namespaces(){
+     return namespaces_;
+  }
   // Language specific namespace / packaging
 
   void add_cpp_include(std::string path) { cpp_includes_.push_back(path); }