Check if the lookup is built or not everytime you query it, to avoid problems of missing a stage (e.g. starting from routing)

Author: MohamedElgammal

vpr/src/pack/pack.cpp

@@ -266,7 +266,6 @@ bool try_pack(t_packer_opts* packer_opts,
     /*       Use the re-cluster API to edit it        */
     /******************* Start *************************/
     VTR_LOG("Start the iterative improvement process\n");
-    init_clb_atoms_lookup(helper_ctx.atoms_lookup);
     //iteratively_improve_packing(*packer_opts, clustering_data, 2);
     VTR_LOG("the iterative improvement process is done\n");
 

vpr/src/pack/re_cluster_util.cpp

@@ -50,6 +50,11 @@ ClusterBlockId atom_to_cluster(const AtomBlockId& atom) {
 
 std::unordered_set<AtomBlockId>* cluster_to_atoms(const ClusterBlockId& cluster) {
     auto& helper_ctx = g_vpr_ctx.mutable_cl_helper();
+
+    //If the lookup is not built yet, build it first
+    if (helper_ctx.atoms_lookup.empty())
+        init_clb_atoms_lookup(helper_ctx.atoms_lookup);
+
     return &(helper_ctx.atoms_lookup[cluster]);
 }