fixing bug in virtual time sampling for models that don't need it

src/networks/model-net/model-net-lp.c

@@ -146,10 +146,13 @@ void mn_event_collect(model_net_wrap_msg *m, tw_lp *lp, char *buffer, int *colle
             break;
         case MN_BASE_PASS:
             sub_msg = ((char*)m)+msg_offsets[((model_net_base_state*)lp->cur_state)->net_id];
+            if (((model_net_base_state*)lp->cur_state)->sub_model_type)
+            {
                 if (g_st_ev_trace == RB_TRACE || g_st_ev_trace == COMMIT_TRACE)
                     (((model_net_base_state*)lp->cur_state)->sub_model_type->rbev_trace)(sub_msg, lp, buffer, collect_flag);
                 else if (g_st_ev_trace == FULL_TRACE)
                     (((model_net_base_state*)lp->cur_state)->sub_model_type->ev_trace)(sub_msg, lp, buffer, collect_flag);
+            }
             break;
         default:  // this shouldn't happen, but can help detect an issue
             type = 9004;
@@ -160,17 +163,20 @@ void mn_event_collect(model_net_wrap_msg *m, tw_lp *lp, char *buffer, int *colle
 void mn_model_stat_collect(model_net_base_state *s, tw_lp *lp, char *buffer)
 {
     // need to call the model level stats collection fn
+    if (s->sub_model_type)
         (*s->sub_model_type->model_stat_fn)(s->sub_state, lp, buffer);
     return;
 }
 
 void mn_sample_event(model_net_base_state *s, tw_bf * bf, tw_lp * lp, void *sample)
 {
+    if (s->sub_model_type)
         (*s->sub_model_type->sample_event_fn)(s->sub_state, bf, lp, sample);
 }
 
 void mn_sample_rc_event(model_net_base_state *s, tw_bf * bf, tw_lp * lp, void *sample)
 {
+    if (s->sub_model_type)
         (*s->sub_model_type->sample_revent_fn)(s->sub_state, bf, lp, sample);
 }
 
@@ -227,16 +233,17 @@ void model_net_base_register(int *do_config_nets){
             else
                 method_array[i]->mn_register(&model_net_base_lp);
             if (g_st_ev_trace || g_st_model_stats || g_st_use_analysis_lps) // for ROSS event tracing
+            {
+                if (method_array[i]->mn_model_stat_register != NULL)
+                //    st_model_type_register(model_net_lp_config_names[i], &mn_model_types[i]);
+                //else
                 {
                     memcpy(&mn_model_types[i], &mn_model_base_type, sizeof(st_model_types));
-
-                if (method_array[i]->mn_model_stat_register == NULL)
-                    st_model_type_register(model_net_lp_config_names[i], &mn_model_types[i]);
-                else
                     method_array[i]->mn_model_stat_register(&mn_model_types[i]);
                 }
             }
         }
+    }
 }
 
 static void base_read_config(const char * anno, model_net_base_params *p){
@@ -481,9 +488,12 @@ void model_net_base_lp_init(
     if (g_st_ev_trace || g_st_model_stats || g_st_use_analysis_lps)
     {
         ns->sub_model_type = model_net_get_model_stat_type(ns->net_id);
+        if (ns->sub_model_type)
+        {
             mn_model_types[ns->net_id].mstat_sz = ns->sub_model_type->mstat_sz;
             mn_model_types[ns->net_id].sample_struct_sz = ns->sub_model_type->sample_struct_sz;
         }
+    }
 
     // NOTE: some models actually expect LP state to be 0 initialized...
     // *cough anything that uses mn_stats_array cough*

src/networks/model-net/model-net.c

@@ -629,7 +629,10 @@ const tw_lptype* model_net_get_lp_type(int net_id)
 
 const st_model_types* model_net_get_model_stat_type(int net_id)
 {
+    if (method_array[net_id]->mn_get_model_stat_types)
        return method_array[net_id]->mn_get_model_stat_types();
+    else
+        return NULL;
 }
 
 void model_net_report_stats(int net_id)