py/modsys: Use MP_REGISTER_ROOT_POINTER().

This uses MP_REGISTER_ROOT_POINTER() to register cur_exception,
sys_exitfunc, mp_sys_path_obj, mp_sys_argv_obj and sys_mutable
instead of using a conditional inside of mp_state_vm_t.

Signed-off-by: David Lechner <david@pybricks.com>

py/modsys.c

@@ -286,4 +286,24 @@ const mp_obj_module_t mp_module_sys = {
 
 MP_REGISTER_MODULE(MP_QSTR_usys, mp_module_sys);
 
+// If MICROPY_PY_SYS_PATH_ARGV_DEFAULTS is not enabled then these two lists
+// must be initialised after the call to mp_init.
+MP_REGISTER_ROOT_POINTER(mp_obj_list_t mp_sys_path_obj);
+MP_REGISTER_ROOT_POINTER(mp_obj_list_t mp_sys_argv_obj);
+
+#if MICROPY_PY_SYS_EXC_INFO
+// current exception being handled, for sys.exc_info()
+MP_REGISTER_ROOT_POINTER(mp_obj_base_t * cur_exception);
 #endif
+
+#if MICROPY_PY_SYS_ATEXIT
+// exposed through sys.atexit function
+MP_REGISTER_ROOT_POINTER(mp_obj_t sys_exitfunc);
+#endif
+
+#if MICROPY_PY_SYS_ATTR_DELEGATION
+// Contains mutable sys attributes.
+MP_REGISTER_ROOT_POINTER(mp_obj_t sys_mutable[MP_SYS_MUTABLE_NUM]);
+#endif
+
+#endif // MICROPY_PY_SYS

py/mpstate.h

@@ -154,31 +154,9 @@ typedef struct _mp_state_vm_t {
     mp_sched_item_t sched_queue[MICROPY_SCHEDULER_DEPTH];
     #endif
 
-    // current exception being handled, for sys.exc_info()
-    #if MICROPY_PY_SYS_EXC_INFO
-    mp_obj_base_t *cur_exception;
-    #endif
-
-    #if MICROPY_PY_SYS_ATEXIT
-    // exposed through sys.atexit function
-    mp_obj_t sys_exitfunc;
-    #endif
-
     // dictionary for the __main__ module
     mp_obj_dict_t dict_main;
 
-    #if MICROPY_PY_SYS
-    // If MICROPY_PY_SYS_PATH_ARGV_DEFAULTS is not enabled then these two lists
-    // must be initialised after the call to mp_init.
-    mp_obj_list_t mp_sys_path_obj;
-    mp_obj_list_t mp_sys_argv_obj;
-
-    #if MICROPY_PY_SYS_ATTR_DELEGATION
-    // Contains mutable sys attributes.
-    mp_obj_t sys_mutable[MP_SYS_MUTABLE_NUM];
-    #endif
-    #endif
-
     // dictionary for overridden builtins
     #if MICROPY_CAN_OVERRIDE_BUILTINS
     mp_obj_dict_t *mp_module_builtins_override_dict;