Fix segfault when exploration trace is empty.

Example:
$ ./bin/simgrid-mc -- ./teshsuite/mc/random-bug/random-bug

diff --git a/src/mc/ModelChecker.cpp b/src/mc/ModelChecker.cpp
index 2b0d821..cb17269 100644 (file)
--- a/src/mc/ModelChecker.cpp
+++ b/src/mc/ModelChecker.cpp
@@ -135,16 +135,18 @@ static void MC_report_crash(int status)
     XBT_INFO("From exit: %i", WEXITSTATUS(status));
   if (not xbt_log_no_loc)
     XBT_INFO("%s core dump was generated by the system.", WCOREDUMP(status) ? "A" : "No");
-  XBT_INFO("Counter-example execution trace:");
-  for (auto const& s : mc_model_checker->get_exploration()->get_textual_trace())
-    XBT_INFO("  %s", s.c_str());
-  XBT_INFO("Path = %s", mc_model_checker->get_exploration()->get_record_trace().to_string().c_str());
-  session_singleton->log_state();
-  if (xbt_log_no_loc) {
-    XBT_INFO("Stack trace not displayed because you passed --log=no_loc");
-  } else {
-    XBT_INFO("Stack trace:");
-    mc_model_checker->get_remote_process().dump_stack();
+  if (mc_model_checker->get_exploration()) {
+    XBT_INFO("Counter-example execution trace:");
+    for (auto const& s : mc_model_checker->get_exploration()->get_textual_trace())
+      XBT_INFO("  %s", s.c_str());
+    XBT_INFO("Path = %s", mc_model_checker->get_exploration()->get_record_trace().to_string().c_str());
+    session_singleton->log_state();
+    if (xbt_log_no_loc) {
+      XBT_INFO("Stack trace not displayed because you passed --log=no_loc");
+    } else {
+      XBT_INFO("Stack trace:");
+      mc_model_checker->get_remote_process().dump_stack();
+    }
   }
 }