From 80fa6f8a0a2994bec31a791679146f2a59620543 Mon Sep 17 00:00:00 2001
From: tangxifan <tangxifan@gmail.com>
Date: Tue, 18 Feb 2020 22:08:51 -0700
Subject: [PATCH] refactored skip nets in LbRouter

---
 openfpga/src/repack/lb_router.cpp | 53 +++++++++++++++++++++++++++----
 openfpga/src/repack/lb_router.h   |  6 +++-
 2 files changed, 51 insertions(+), 8 deletions(-)

diff --git a/openfpga/src/repack/lb_router.cpp b/openfpga/src/repack/lb_router.cpp
index 16c7f8f35..267d8d3f9 100644
--- a/openfpga/src/repack/lb_router.cpp
+++ b/openfpga/src/repack/lb_router.cpp
@@ -80,14 +80,32 @@ LbRouter::t_trace* LbRouter::find_node_in_rt(t_trace* rt, const LbRRNodeId& rt_i
 /**************************************************
  * Private mutators
  *************************************************/
-void LbRouter::reset_explored_node_tb() {
-  for (t_explored_node_stats& explored_node : explored_node_tb_) {
-    explored_node.prev_index = LbRRNodeId::INVALID();
-    explored_node.explored_id = OPEN;
-    explored_node.inet = OPEN;
-    explored_node.enqueue_id = OPEN;
-    explored_node.enqueue_cost = 0;
+bool LbRouter::is_skip_route_net(const LbRRGraph& lb_rr_graph,
+                                 t_trace* rt) {
+  /* Validate if the rr_graph is the one we used to initialize the router */
+  VTR_ASSERT(true == matched_lb_rr_graph(lb_rr_graph));
+
+  if (rt == nullptr) {
+    return false; /* Net is not routed, therefore must route net */
   }
+
+  LbRRNodeId inode = rt->current_node;
+
+  /* Determine if node is overused */
+  if (routing_status_[inode].occ > lb_rr_graph.node_capacity(inode)) {
+    /* Conflict between this net and another net at this node, reroute net */
+    return false;
+  }
+
+  /* Recursively check that rest of route tree does not have a conflict */
+  for (unsigned int i = 0; i < rt->next_nodes.size(); i++) {
+    if (!is_skip_route_net(lb_rr_graph, &rt->next_nodes[i])) {
+      return false;
+    }
+  }
+
+  /* No conflict, this net's current route is legal, skip routing this net */
+  return true;
 }
 
 bool LbRouter::add_to_rt(t_trace* rt, const LbRRNodeId& node_index, const int& irt_net) {
@@ -123,6 +141,13 @@ bool LbRouter::add_to_rt(t_trace* rt, const LbRRNodeId& node_index, const int& i
   return false;
 }
 
+void LbRouter::add_source_to_rt(const int& inet) {
+  /* TODO: Validate net id */
+  VTR_ASSERT(nullptr == lb_nets_[inet].rt_tree);
+  lb_nets_[inet].rt_tree = new t_trace;
+  lb_nets_[inet].rt_tree->current_node = lb_nets_[inet].terminals[0];
+}
+
 void LbRouter::expand_rt_rec(t_trace* rt,
                              const LbRRNodeId& prev_index, 
                              reservable_pq<t_expansion_node, std::vector<t_expansion_node>, compare_expansion_node>& pq,
@@ -276,4 +301,18 @@ bool LbRouter::matched_lb_rr_graph(const LbRRGraph& lb_rr_graph) const {
         && (explored_node_tb_.size() == lb_rr_graph.nodes().size()) );
 }
 
+/**************************************************
+ * Private Initializer and cleaner
+ *************************************************/
+void LbRouter::reset_explored_node_tb() {
+  for (t_explored_node_stats& explored_node : explored_node_tb_) {
+    explored_node.prev_index = LbRRNodeId::INVALID();
+    explored_node.explored_id = OPEN;
+    explored_node.inet = OPEN;
+    explored_node.enqueue_id = OPEN;
+    explored_node.enqueue_cost = 0;
+  }
+}
+
+
 } /* end namespace openfpga */
diff --git a/openfpga/src/repack/lb_router.h b/openfpga/src/repack/lb_router.h
index 1d07954df..92aca94c1 100644
--- a/openfpga/src/repack/lb_router.h
+++ b/openfpga/src/repack/lb_router.h
@@ -200,8 +200,9 @@ class LbRouter {
     t_trace* find_node_in_rt(t_trace* rt, const LbRRNodeId& rt_index);
 
   private : /* Private mutators */
-    void reset_explored_node_tb();
+    bool is_skip_route_net(const LbRRGraph& lb_rr_graph, t_trace* rt);
     bool add_to_rt(t_trace* rt, const LbRRNodeId& node_index, const int& irt_net);
+    void add_source_to_rt(const int& inet);
     void expand_rt_rec(t_trace* rt,
                        const LbRRNodeId& prev_index, 
                        reservable_pq<t_expansion_node, std::vector<t_expansion_node>, compare_expansion_node>& pq,
@@ -231,6 +232,9 @@ class LbRouter {
      */
     bool matched_lb_rr_graph(const LbRRGraph& lb_rr_graph) const;
 
+  private :  /* Private initializer and cleaner */
+    void reset_explored_node_tb();
+
   private : /* Stores all data needed by intra-logic cluster_ctx.blocks router */
     /* Logical Netlist Info */
     std::vector<t_net> lb_nets_; /* Pointer to vector of intra logic cluster_ctx.blocks nets and their connections */