add flat router warning in case of reading route file fails

Author: saaramahmoudi

vpr/src/base/read_route.cpp

@@ -192,7 +192,7 @@ static void process_nets(const Netlist<>& net_list, std::ifstream& fp, ClusterNe
 
         if (0 != net_list.net_name(inet).compare(name)) {
             vpr_throw(VPR_ERROR_ROUTE, filename, lineno,
-                      "Net name %s for net number %lu specified in the routing file does not match given %s",
+                      "Net name %s for net number %lu specified in the routing file does not match given %s. if route_file generated by flat router, you need to specifiy flat_routing true in command-line option",
                       name.c_str(), size_t(inet), net_list.net_name(inet).c_str());
         }
 
@@ -207,7 +207,7 @@ static void process_nets(const Netlist<>& net_list, std::ifstream& fp, ClusterNe
 
         if (0 != net_list.net_name(inet).compare(name)) {
             vpr_throw(VPR_ERROR_ROUTE, filename, lineno,
-                      "Net name %s for net number %lu specified in the routing file does not match given %s",
+                      "Net name %s for net number %lu specified in the routing file does not match given %s. if route_file generated by flat router, you need to specifiy flat_routing true in command-line option",
                       name.c_str(), size_t(inet), net_list.net_name(inet).c_str());
         }
 
@@ -323,7 +323,7 @@ static void process_nodes(const Netlist<>& net_list, std::ifstream& fp, ClusterN
             ptc = atoi(tokens[5 + offset].c_str());
             if (rr_graph.node_ptc_num(RRNodeId(inode)) != ptc) {
                 vpr_throw(VPR_ERROR_ROUTE, filename, lineno,
-                          "The ptc num of node %d does not match the rr graph", inode);
+                          "The ptc num of node %d does not match the rr graph, if route_file generated by flat router, you need to specifiy flat_routing true in command-line option", inode);
             }
 
             /*Process switches and pb pin info if it is ipin or opin type*/