8047934: Adding new API for unlocking diagnostic argument.

Summary: New API for unlocking diagnostic argument.
Reviewed-by: dholmes, ccheung, egahlin, iklam, bdelsart

src/share/vm/runtime/arguments.cpp

@@ -3617,6 +3617,8 @@ jint Arguments::parse(const JavaVMInitArgs* args) {
   bool settings_file_specified = false;
   bool needs_hotspotrc_warning = false;
 
+  ArgumentsExt::process_options(args);
+
   const char* flags_file;
   int index;
   for (index = 0; index < args->nOptions; index++) {

src/share/vm/runtime/arguments_ext.hpp

@@ -34,6 +34,7 @@ public:
   static inline bool check_gc_consistency_user();
   static inline bool check_gc_consistency_ergo();
   static inline bool check_vm_args_consistency();
+  static        void process_options(const JavaVMInitArgs* args) {}
 };
 
 void ArgumentsExt::select_gc_ergonomically() {

src/share/vm/runtime/globals.cpp

@@ -243,6 +243,11 @@ bool Flag::is_unlocked() const {
   return is_unlocked_ext();
 }
 
+void Flag::unlock_diagnostic() {
+  assert(is_diagnostic(), "sanity");
+  _flags = Flags(_flags & ~KIND_DIAGNOSTIC);
+}
+
 // Get custom message for this locked flag, or return NULL if
 // none is available.
 void Flag::get_locked_message(char* buf, int buflen) const {

src/share/vm/runtime/globals.hpp

@@ -313,6 +313,8 @@ struct Flag {
   bool is_writeable_ext() const;
   bool is_external_ext() const;
 
+  void unlock_diagnostic();
+
   void get_locked_message(char*, int) const;
   void get_locked_message_ext(char*, int) const;