enable option to force molecule placement on a specified primitive site

Author: KA7E

libs/libarchfpga/src/physical_types.h

@@ -1287,7 +1287,7 @@ class t_pb_graph_node {
     int num_output_pin_class;   /* number of output pin classes that this pb_graph_node has */
 
     int total_primitive_count; /* total number of this primitive type in the cluster */
-     int flat_site_index;       /* index of this primitive within sites of its type in this cluster  */
+    int flat_site_index;       /* index of this primitive within sites of its type in this cluster  */
 
 
     /* Interconnect instances for this pb

vpr/src/pack/cluster_placement.cpp

@@ -86,10 +86,14 @@ t_cluster_placement_stats* alloc_and_load_cluster_placement_stats() {
  * primitives_list - a list of primitives indexed to match atom_block_ids of molecule.
  *                   Expects an allocated array of primitives ptrs as inputs.
  *                   This function loads the array with the lowest cost primitives that implement molecule
+ * force_site - optional user-specified primitive site on which to place the molecule; if a force_site
+ *              argument is provided, the function either selects the specified site or reports failure.
+ *              If the force_site argument is set to its default value (-1), vpr selects an available site.
  */
 bool get_next_primitive_list(t_cluster_placement_stats* cluster_placement_stats,
                              const t_pack_molecule* molecule,
-                             t_pb_graph_node** primitives_list) {
+                             t_pb_graph_node** primitives_list,
+                             int force_site) {
     std::unordered_multimap<int, t_cluster_placement_primitive*>::iterator best;
 
     int i;
@@ -136,6 +140,23 @@ bool get_next_primitive_list(t_cluster_placement_stats* cluster_placement_stats,
                         continue;
                     }
 
+
+                    /* check for force site match, if applicable */
+                    if (force_site > -1) {
+                        if (force_site == it->second->pb_graph_node->flat_site_index) {
+                            cost = try_place_molecule(molecule, it->second->pb_graph_node, primitives_list);
+                            if (cost < HUGE_POSITIVE_FLOAT) {
+                                cluster_placement_stats->move_primitive_to_inflight(i, it);
+                                return true;
+                            } else {
+                                break;
+                            }
+                        } else {
+                            ++it;
+                            continue;
+                        }
+                    }
+
                     /* try place molecule at root location cur */
                     cost = try_place_molecule(molecule, it->second->pb_graph_node, primitives_list);
 
@@ -153,6 +174,11 @@ bool get_next_primitive_list(t_cluster_placement_stats* cluster_placement_stats,
         }
     }
 
+    /* if force_site was specified but not found, fail */
+    if (force_site > -1) {
+        found_best = false;
+    }
+
     if (!found_best) {
         /* failed to find a placement */
         for (i = 0; i < molecule->num_blocks; i++) {

vpr/src/pack/cluster_placement.h

@@ -11,7 +11,8 @@ t_cluster_placement_stats* alloc_and_load_cluster_placement_stats();
 bool get_next_primitive_list(
     t_cluster_placement_stats* cluster_placement_stats,
     const t_pack_molecule* molecule,
-    t_pb_graph_node** primitives_list);
+    t_pb_graph_node** primitives_list,
+    int force_site = -1);
 void commit_primitive(t_cluster_placement_stats* cluster_placement_stats,
                       const t_pb_graph_node* primitive);
 void set_mode_cluster_placement_stats(const t_pb_graph_node* complex_block,

vpr/src/pack/cluster_util.cpp

@@ -932,7 +932,8 @@ e_block_pack_status try_pack_molecule(t_cluster_placement_stats* cluster_placeme
                                       int feasible_block_array_size,
                                       t_ext_pin_util max_external_pin_util,
                                       PartitionRegion& temp_cluster_pr,
-                                      NocGroupId& temp_noc_grp_id) {
+                                      NocGroupId& temp_noc_grp_id,
+                                      int force_site) {
     t_pb* parent;
     t_pb* cur_pb;
 
@@ -1009,7 +1010,7 @@ e_block_pack_status try_pack_molecule(t_cluster_placement_stats* cluster_placeme
 
     while (block_pack_status != e_block_pack_status::BLK_PASSED) {
         if (get_next_primitive_list(cluster_placement_stats_ptr, molecule,
-                                    primitives_list)) {
+                                    primitives_list, force_site)) {
             block_pack_status = e_block_pack_status::BLK_PASSED;
 
             int failed_location = 0;

vpr/src/pack/cluster_util.h

@@ -214,7 +214,8 @@ e_block_pack_status try_pack_molecule(t_cluster_placement_stats* cluster_placeme
                                       int feasible_block_array_size,
                                       t_ext_pin_util max_external_pin_util,
                                       PartitionRegion& temp_cluster_pr,
-                                      NocGroupId& temp_noc_grp_id);
+                                      NocGroupId& temp_noc_grp_id,
+                                      int force_site = -1);
 
 void try_fill_cluster(const t_packer_opts& packer_opts,
                       t_cluster_placement_stats* cur_cluster_placement_stats_ptr,
@@ -493,4 +494,4 @@ bool cleanup_pb(t_pb* pb);
 void alloc_and_load_pb_stats(t_pb* pb, const int feasible_block_array_size);
 
 void init_clb_atoms_lookup(vtr::vector<ClusterBlockId, std::unordered_set<AtomBlockId>>& atoms_lookup);
-#endif
+#endif

vpr/src/pack/re_cluster_util.cpp

@@ -130,7 +130,8 @@ bool start_new_cluster_for_mol(t_pack_molecule* molecule,
                                t_lb_router_data** router_data,
                                PartitionRegion& temp_cluster_pr,
                                NocGroupId& temp_cluster_noc_grp_id,
-                               enum e_detailed_routing_stages detailed_routing_stage) {
+                               enum e_detailed_routing_stages detailed_routing_stage,
+                               int force_site) {
     auto& atom_ctx = g_vpr_ctx.atom();
     auto& floorplanning_ctx = g_vpr_ctx.mutable_floorplanning();
     auto& helper_ctx = g_vpr_ctx.mutable_cl_helper();
@@ -172,7 +173,8 @@ bool start_new_cluster_for_mol(t_pack_molecule* molecule,
                                     0,
                                     FULL_EXTERNAL_PIN_UTIL,
                                     temp_cluster_pr,
-                                    temp_cluster_noc_grp_id);
+                                    temp_cluster_noc_grp_id,
+                                    force_site);
 
     // If clustering succeeds, add it to the clb netlist
     if (pack_result == e_block_pack_status::BLK_PASSED) {
@@ -215,7 +217,8 @@ bool pack_mol_in_existing_cluster(t_pack_molecule* molecule,
                                   t_clustering_data& clustering_data,
                                   t_lb_router_data*& router_data,
                                   enum e_detailed_routing_stages detailed_routing_stage,
-                                  bool enable_pin_feasibility_filter) {
+                                  bool enable_pin_feasibility_filter,
+                                  int force_site) {
 
     auto& helper_ctx = g_vpr_ctx.mutable_cl_helper();
     auto& cluster_ctx = g_vpr_ctx.mutable_clustering();
@@ -250,7 +253,8 @@ bool pack_mol_in_existing_cluster(t_pack_molecule* molecule,
                                     helper_ctx.feasible_block_array_size,
                                     target_ext_pin_util,
                                     temp_cluster_pr,
-                                    temp_cluster_noc_grp_id);
+                                    temp_cluster_noc_grp_id,
+                                    force_site);
 
     // If clustering succeeds, add it to the clb netlist
     if (pack_result == e_block_pack_status::BLK_PASSED) {

vpr/src/pack/re_cluster_util.h

@@ -84,6 +84,10 @@ void remove_mol_from_cluster(const t_pack_molecule* molecule,
  *                                the function does not run a detailed intra-cluster routing-based legality check.
  *                                If many molecules will be added to a cluster, this option enables use of a single
  *                                routing check on the completed cluster (vs many incremental checks).
+ * @param force_site: optional user-specified primitive site on which to place the molecule; this is passed to
+ *                    try_pack_molecule and then to get_next_primitive_site. If a force_site argument is provided,
+ *                    the molecule is either placed on the specified site or fails to add to the cluster.
+ *                    If the force_site argument is set to its default value (-1), vpr selects an available site.
  */
 bool start_new_cluster_for_mol(t_pack_molecule* molecule,
                                const t_logical_block_type_ptr& type,
@@ -97,7 +101,8 @@ bool start_new_cluster_for_mol(t_pack_molecule* molecule,
                                t_lb_router_data** router_data,
                                PartitionRegion& temp_cluster_pr,
                                NocGroupId& temp_cluster_noc_grp_id,
-                               enum e_detailed_routing_stages detailed_routing_stage = E_DETAILED_ROUTE_FOR_EACH_ATOM);
+                               enum e_detailed_routing_stages detailed_routing_stage = E_DETAILED_ROUTE_FOR_EACH_ATOM,
+                               int force_site = -1);
 
 /**
  * @brief A function that packs a molecule into an existing cluster
@@ -118,6 +123,10 @@ bool start_new_cluster_for_mol(t_pack_molecule* molecule,
  *                                If many molecules will be added to a cluster, this option enables use of a single
  *                                routing check on the completed cluster (vs many incremental checks).
  * @param enable_pin_feasibility_filter: do a pin couting based legality check (before or in place of intra-cluster routing check).
+ * @param force_site: optional user-specified primitive site on which to place the molecule; this is passed to
+ *                    try_pack_molecule and then to get_next_primitive_site. If a force_site argument is provided,
+ *                    the molecule is either placed on the specified site or fails to add to the cluster.
+ *                    If the force_site argument is set to its default value (-1), vpr selects an available site.
  */
 bool pack_mol_in_existing_cluster(t_pack_molecule* molecule,
                                   int molecule_size,
@@ -127,7 +136,8 @@ bool pack_mol_in_existing_cluster(t_pack_molecule* molecule,
                                   t_clustering_data& clustering_data,
                                   t_lb_router_data*& router_data,
                                   enum e_detailed_routing_stages detailed_routing_stage = E_DETAILED_ROUTE_FOR_EACH_ATOM,
-                                  bool enable_pin_feasibility_filter = true);
+                                  bool enable_pin_feasibility_filter = true,
+                                  int force_site = -1);
 
 /**
  * @brief A function that fix the clustered netlist if the move is performed