[VPR] Deploy find_channel_nodes() to router lookahead map functions

Author: tangxifan

vpr/src/device/rr_spatial_lookup.cpp

@@ -77,6 +77,9 @@ RRNodeId RRSpatialLookup::find_node(int x,
 std::vector<RRNodeId> RRSpatialLookup::find_channel_nodes(int x,
                                                           int y,
                                                           t_rr_type type) const {
+    /* TODO: The implementation of this API should be worked 
+     * when rr_node_indices adapts RRNodeId natively!
+     */
     std::vector<RRNodeId> channel_nodes;
 
     /* Pre-check: the x, y, type are valid! Otherwise, return an empty vector */

vpr/src/route/router_lookahead_map.cpp

@@ -547,7 +547,7 @@ static RRNodeId get_start_node(int start_x, int start_y, int target_x, int targe
     const auto& temp_rr_graph = device_ctx.rr_graph; //TODO rename to rr_graph once the rr_graph below is unneeded
     auto& rr_graph = device_ctx.rr_nodes;
 
-    int result = UNDEFINED;
+    RRNodeId result = RRNodeId::INVALID();
 
     if (rr_type != CHANX && rr_type != CHANY) {
         VPR_FATAL_ERROR(VPR_ERROR_ROUTE, "Must start lookahead routing from CHANX or CHANY node\n");
@@ -561,19 +561,11 @@ static RRNodeId get_start_node(int start_x, int start_y, int target_x, int targe
 
     int start_lookup_x = start_x;
     int start_lookup_y = start_y;
-    if (rr_type == CHANX) {
-        //Bizarely, rr_node_indices stores CHANX with swapped x/y...
-        std::swap(start_lookup_x, start_lookup_y);
-    }
 
-    const std::vector<int>& channel_node_list = device_ctx.rr_node_indices[rr_type][start_lookup_x][start_lookup_y][0];
 
     /* find first node in channel that has specified segment index and goes in the desired direction */
-    for (unsigned itrack = 0; itrack < channel_node_list.size(); itrack++) {
-        int node_ind = channel_node_list[itrack];
-        if (node_ind < 0) continue;
-
-        RRNodeId node_id(node_ind);
+    for (const RRNodeId& node_id : device_ctx.rr_graph.node_lookup().find_channel_nodes(start_lookup_x, start_lookup_y, rr_type)) {
+        if (!node_id) continue;
 
         VTR_ASSERT(temp_rr_graph.node_type(node_id) == rr_type);
 
@@ -583,15 +575,15 @@ static RRNodeId get_start_node(int start_x, int start_y, int target_x, int targe
 
         if ((node_direction == direction || node_direction == BI_DIRECTION) && node_seg_ind == seg_index) {
             /* found first track that has the specified segment index and goes in the desired direction */
-            result = node_ind;
+            result = node_id;
             if (track_offset == 0) {
                 break;
             }
             track_offset -= 2;
         }
     }
 
-    return RRNodeId(result);
+    return result;
 }
 
 /* runs Dijkstra's algorithm from specified node until all nodes have been visited. Each time a pin is visited, the delay/congestion information

vpr/src/route/router_lookahead_map_utils.cpp

@@ -382,8 +382,6 @@ t_chan_ipins_delays compute_router_chan_ipin_lookahead() {
 
     chan_ipins_delays.resize(device_ctx.physical_tile_types.size());
 
-    std::vector<int> rr_nodes_at_loc;
-
     //We assume that the routing connectivity of each instance of a physical tile is the same,
     //and so only measure one instance of each type
     for (auto tile_type : device_ctx.physical_tile_types) {
@@ -406,13 +404,8 @@ t_chan_ipins_delays compute_router_chan_ipin_lookahead() {
         for (int ix = min_x; ix < max_x; ix++) {
             for (int iy = min_y; iy < max_y; iy++) {
                 for (auto rr_type : {CHANX, CHANY}) {
-                    rr_nodes_at_loc.clear();
-
-                    get_rr_node_indices(device_ctx.rr_node_indices, ix, iy, rr_type, &rr_nodes_at_loc);
-                    for (int inode : rr_nodes_at_loc) {
-                        if (inode < 0) continue;
-
-                        RRNodeId node_id(inode);
+                    for (const RRNodeId& node_id : device_ctx.rr_graph.node_lookup().find_channel_nodes(ix, iy, rr_type)) {
+                        if (!node_id) continue;
 
                         //Find the IPINs which are reachable from the wires within the bounding box
                         //around the selected tile location