score: Add optional _CPU_Context_Destroy()

Update #3077.

cpukit/score/cpu/no_cpu/rtems/score/cpu.h

@@ -815,6 +815,25 @@ uint32_t   _CPU_ISR_Get_level( void );
 
 /* Context handler macros */
 
+/**
+ * @ingroup CPUContext
+ *
+ * @brief Destroys the context of the thread.
+ *
+ * It must be implemented as a macro and an implementation is optional.  The
+ * default implementation does nothing.
+ *
+ * @param[in] _the_thread The corresponding thread.
+ * @param[in] _the_context The context to destroy.
+ *
+ * Port Specific Information:
+ *
+ * XXX document implementation including references if appropriate
+ */
+#define _CPU_Context_Destroy( _the_thread, _the_context ) \
+  { \
+  }
+
 /**
  *  @ingroup CPUContext
  * 

cpukit/score/include/rtems/score/context.h

@@ -146,6 +146,13 @@ extern "C" {
 #define _Context_Save_fp( _fp ) \
    _CPU_Context_save_fp( _fp )
 
+#if defined(_CPU_Context_Destroy)
+  #define _Context_Destroy( _the_thread, _the_context ) \
+    _CPU_Context_Destroy( _the_thread, _the_context )
+#else
+  #define _Context_Destroy( _the_thread, _the_context )
+#endif
+
 #ifdef __cplusplus
 }
 #endif

cpukit/score/src/threadrestart.c

@@ -205,7 +205,7 @@ static void _Thread_Free( Thread_Control *the_thread )
 #endif
 
   _Thread_queue_Destroy( &the_thread->Join_queue );
-
+  _Context_Destroy( the_thread, &the_thread->Registers );
   _Objects_Free( &information->Objects, &the_thread->Object );
 }