Merge pull request #10632 from eder-matheus/pad_non_determinism

pad: add custom comparator for GridGraphEdge set to prevent non-determinism

Author: eder-matheus

src/pad/src/RDLRouter.cpp

@@ -41,6 +41,17 @@ namespace pad {
 
 namespace {
 
+// Order routes by their source terminal id so ripup iteration (and the edge
+// re-add order it drives) is deterministic, not heap-address dependent.
+struct RDLRoutePtrLess
+{
+  bool operator()(const std::shared_ptr<RDLRoute>& lhs,
+                  const std::shared_ptr<RDLRoute>& rhs) const
+  {
+    return lhs->getTerminal()->getId() < rhs->getTerminal()->getId();
+  }
+};
+
 bool compareRouteTargets(const RouteTarget& lhs, const RouteTarget& rhs)
 {
   if (lhs.center.x() != rhs.center.x()) {
@@ -381,7 +392,7 @@ void RDLRouter::route(const std::vector<odb::dbNet*>& nets)
   makeGraph();
 
   // Determine access points
-  std::unordered_map<odb::Point, std::set<GridGraphEdge>> remove_edges;
+  std::unordered_map<odb::Point, GridGraphEdgeSet> remove_edges;
   for (auto& [net, iterm_targets] : routing_targets_) {
     for (auto& [iterm, targets] : iterm_targets) {
       for (auto& target : targets) {
@@ -649,7 +660,7 @@ void RDLRouter::route(const std::vector<odb::dbNet*>& nets)
       }
 
       // find routes to ripup
-      std::set<RDLRoutePtr> ripup;
+      std::set<RDLRoutePtr, RDLRoutePtrLess> ripup;
       for (const auto& failed_route : failed) {
         for (const auto& route : routes_) {
           if (!route->isRouted()) {
@@ -797,7 +808,7 @@ static odb::Point getValidGridPoint(
 }
 
 void RDLRouter::cleanupGraphEdges(
-    const std::unordered_map<odb::Point, std::set<GridGraphEdge>>& edges)
+    const std::unordered_map<odb::Point, GridGraphEdgeSet>& edges)
 {
   if (edges.empty()) {
     return;
@@ -824,7 +835,7 @@ void RDLRouter::cleanupGraphEdges(
 
 void RDLRouter::populateTerminalAccessPoints(
     RouteTarget& target,
-    std::unordered_map<odb::Point, std::set<GridGraphEdge>>& edges) const
+    std::unordered_map<odb::Point, GridGraphEdgeSet>& edges) const
 {
   // determine new access point in graph
   std::set<odb::Point> snap_pts;
@@ -1181,29 +1192,24 @@ bool RDLRouter::is45DegreeEdge(const odb::Point& pt0,
   return RDLRoute::is45DegreeEdge(pt0, pt1);
 }
 
-std::set<GridGraphEdge> RDLRouter::getVertexEdges(
-    const GridGraphVertex& vertex) const
+GridGraphEdgeSet RDLRouter::getVertexEdges(const GridGraphVertex& vertex) const
 {
-  std::set<GridGraphEdge> edges;
+  GridGraphEdgeSet edges;
 
+  // The graph is undirected, so out_edges already yields every incident edge.
   GridGraph::out_edge_iterator oit, oend;
   std::tie(oit, oend) = boost::out_edges(vertex, graph_);
   for (; oit != oend; oit++) {
     edges.insert(*oit);
   }
-  GridGraph::in_edge_iterator iit, iend;
-  std::tie(iit, iend) = boost::in_edges(vertex, graph_);
-  for (; iit != iend; iit++) {
-    edges.insert(*iit);
-  }
 
   return edges;
 }
 
 std::vector<RDLRouter::GridEdge> RDLRouter::commitRoute(
     const std::vector<GridGraphVertex>& route)
 {
-  std::set<GridGraphEdge> edges;
+  GridGraphEdgeSet edges;
   for (const auto& v : route) {
     const auto v_edges = getVertexEdges(v);
     edges.insert(v_edges.begin(), v_edges.end());

src/pad/src/RDLRouter.h

@@ -3,6 +3,7 @@
 
 #pragma once
 
+#include <algorithm>
 #include <cstdint>
 #include <map>
 #include <memory>
@@ -67,6 +68,18 @@ using GridWeightMap
 using GridGraphVertex = GridGraph::vertex_descriptor;
 using GridGraphEdge = GridGraph::edge_descriptor;
 
+// Order edges by (source, target) vertex indices; the descriptor's default
+// operator< compares a heap pointer, giving build-dependent iteration.
+struct GridGraphEdgeLess
+{
+  bool operator()(const GridGraphEdge& lhs, const GridGraphEdge& rhs) const
+  {
+    return std::minmax(lhs.m_source, lhs.m_target)
+           < std::minmax(rhs.m_source, rhs.m_target);
+  }
+};
+using GridGraphEdgeSet = std::set<GridGraphEdge, GridGraphEdgeLess>;
+
 struct RouteTarget
 {
   // center point of the target shape
@@ -213,11 +226,11 @@ class RDLRouter
 
   void populateTerminalAccessPoints(
       RouteTarget& target,
-      std::unordered_map<odb::Point, std::set<GridGraphEdge>>& edges) const;
+      std::unordered_map<odb::Point, GridGraphEdgeSet>& edges) const;
   void cleanupTerminalAccessPoints(odb::dbITerm* iterm,
                                    std::vector<RouteTarget>& targets) const;
   void cleanupGraphEdges(
-      const std::unordered_map<odb::Point, std::set<GridGraphEdge>>& edges);
+      const std::unordered_map<odb::Point, GridGraphEdgeSet>& edges);
   std::set<odb::Point> generateTerminalAccessPoints(const odb::Point& pt,
                                                     bool do_x) const;
   TerminalAccess insertTerminalAccess(const RouteTarget& target,
@@ -227,7 +240,7 @@ class RDLRouter
   odb::PtrMap<odb::dbITerm, std::vector<RouteTarget>> generateRoutingTargets(
       odb::dbNet* net) const;
   odb::dbTechLayer* getOtherLayer(odb::dbTechVia* via) const;
-  std::set<GridGraphEdge> getVertexEdges(const GridGraphVertex& vertex) const;
+  GridGraphEdgeSet getVertexEdges(const GridGraphVertex& vertex) const;
 
   void buildIntialRouteSet();
   int reportFailedRoutes(

src/pad/test/rdl_route_failed.ok

@@ -10,53 +10,45 @@
 [INFO PAD-0037] End of routing iteration 2: 85.4% complete
 [INFO PAD-0037] End of routing iteration 3: 81.9% complete
 [INFO PAD-0037] End of routing iteration 4: 84.4% complete
-[INFO PAD-0037] End of routing iteration 5: 89.0% complete
-[INFO PAD-0037] End of routing iteration 6: 89.9% complete
-[INFO PAD-0037] End of routing iteration 7: 89.5% complete
-[INFO PAD-0037] End of routing iteration 8: 89.0% complete
-[INFO PAD-0037] End of routing iteration 9: 88.8% complete
-[INFO PAD-0037] End of routing iteration 10: 88.8% complete
-[WARNING PAD-0006] Failed to route the following 17 nets:
+[INFO PAD-0037] End of routing iteration 5: 89.2% complete
+[INFO PAD-0037] End of routing iteration 6: 90.1% complete
+[INFO PAD-0037] End of routing iteration 7: 90.3% complete
+[INFO PAD-0037] End of routing iteration 8: 90.3% complete
+[INFO PAD-0037] End of routing iteration 9: 89.2% complete
+[INFO PAD-0037] End of routing iteration 10: 90.3% complete
+[WARNING PAD-0006] Failed to route the following 13 nets:
   DVDD
     BUMP_11_3/PAD -> u_v18_6/DVDD, u_v18_7/DVDD, u_v18_5/DVDD, u_v18_4/DVDD, u_v18_8/DVDD, ... (67 possible terminals)
     BUMP_16_11/PAD -> u_v18_15/DVDD, u_v18_16/DVDD, u_v18_14/DVDD, u_v18_13/DVDD, u_v18_12/DVDD, ... (67 possible terminals)
     BUMP_1_13/PAD -> u_v18_26/DVDD, u_v18_27/DVDD, u_v18_28/DVDD, u_v18_25/DVDD, u_v18_29/DVDD, ... (67 possible terminals)
-    BUMP_4_1/PAD -> u_v18_1/DVDD, u_v18_2/DVDD, u_v18_0/DVDD, u_v18_3/DVDD, u_v18_4/DVDD, ... (67 possible terminals)
   DVSS
-    BUMP_0_8/PAD -> u_vzz_30/DVSS, u_vzz_29/DVSS, u_vzz_31/DVSS, u_vzz_32/DVSS, u_vzz_28/DVSS, ... (67 possible terminals)
     BUMP_15_11/PAD -> u_vzz_15/DVSS, u_vzz_16/DVSS, u_vzz_14/DVSS, u_vzz_13/DVSS, u_vzz_12/DVSS, ... (67 possible terminals)
     BUMP_15_7/PAD -> u_vzz_12/DVSS, u_vzz_13/DVSS, u_vzz_11/DVSS, u_vzz_14/DVSS, u_vzz_10/DVSS, ... (67 possible terminals)
     BUMP_1_9/PAD -> u_vzz_29/DVSS, u_vzz_30/DVSS, u_vzz_28/DVSS, u_vzz_31/DVSS, u_vzz_27/DVSS, ... (67 possible terminals)
+  VDD
+    BUMP_11_12/PAD -> u_vdd_9/VDD, u_vdd_pll/VDD, u_vdd_8/VDD, u_vdd_7/VDD, u_vdd_10/VDD, ... (33 possible terminals)
+    BUMP_1_10/PAD -> u_vdd_13/VDD, u_vdd_14/VDD, u_vdd_12/VDD, u_vdd_15/VDD, u_vdd_11/VDD, ... (33 possible terminals)
   VSS
+    BUMP_0_10/PAD -> u_vss_13/VSS, u_vss_14/VSS, u_vss_12/VSS, u_vss_15/VSS, u_vss_11/VSS, ... (33 possible terminals)
     BUMP_14_9/PAD -> u_vss_6/VSS, u_vss_5/VSS, u_vss_7/VSS, u_vss_4/VSS, u_vss_8/VSS, ... (33 possible terminals)
     BUMP_16_6/PAD -> u_vss_5/VSS, u_vss_6/VSS, u_vss_4/VSS, u_vss_7/VSS, u_vss_3/VSS, ... (33 possible terminals)
+  p_bsg_tag_data_o
+    BUMP_2_10/PAD -> u_bsg_tag_data_o/PAD
   p_clk_A_i
     BUMP_7_13/PAD -> u_clk_A_i/PAD
-  p_clk_async_reset_i
-    BUMP_9_14/PAD -> u_clk_async_reset_i/PAD
   p_co2_v_o
     BUMP_0_13/PAD -> u_co2_v_o/PAD
-  p_ddr_addr_15_o
-    BUMP_4_0/PAD -> u_ddr_addr_15_o/PAD
   p_ddr_addr_2_o
     BUMP_8_2/PAD -> u_ddr_addr_2_o/PAD
-  p_ddr_addr_6_o
-    BUMP_7_0/PAD -> u_ddr_addr_6_o/PAD
-  p_ddr_addr_7_o
-    BUMP_7_1/PAD -> u_ddr_addr_7_o/PAD
+  p_ddr_addr_4_o
+    BUMP_7_4/PAD -> u_ddr_addr_4_o/PAD
   p_ddr_ck_n_o
     BUMP_11_4/PAD -> u_ddr_ck_n_o/PAD
-  p_ddr_dq_0_io
-    BUMP_3_7/PAD -> u_ddr_dq_0_io/PAD
-  p_ddr_dq_11_io
-    BUMP_4_5/PAD -> u_ddr_dq_11_io/PAD
-  p_ddr_dq_13_io
-    BUMP_3_5/PAD -> u_ddr_dq_13_io/PAD
-  p_ddr_dq_2_io
-    BUMP_1_8/PAD -> u_ddr_dq_2_io/PAD
+  p_ddr_dq_7_io
+    BUMP_4_10/PAD -> u_ddr_dq_7_io/PAD
   p_ddr_dq_8_io
     BUMP_0_4/PAD -> u_ddr_dq_8_io/PAD
   p_ddr_dq_9_io
     BUMP_1_4/PAD -> u_ddr_dq_9_io/PAD
-[ERROR PAD-0007] Failed to route 17 nets.
+[ERROR PAD-0007] Failed to route 13 nets.
 pass

src/pad/test/rdl_route_max_iterations.ok

@@ -13,7 +13,6 @@
 [WARNING PAD-0006] Failed to route the following 18 nets:
   DVDD
     BUMP_11_13/PAD -> u_v18_19/DVDD, u_v18_20/DVDD, u_v18_18/DVDD, u_v18_21/DVDD, u_v18_17/DVDD, ... (67 possible terminals)
-    BUMP_7_3/PAD -> u_v18_3/DVDD, u_v18_4/DVDD, u_v18_2/DVDD, u_v18_5/DVDD, u_v18_1/DVDD, ... (67 possible terminals)
   VSS
     BUMP_0_7/PAD -> u_vss_14/VSS, u_vss_13/VSS, u_vss_15/VSS, u_vss_12/VSS, u_vss_0/VSS, ... (33 possible terminals)
     BUMP_10_13/PAD -> u_vss_9/VSS, u_vss_pll/VSS, u_vss_10/VSS, u_vss_8/VSS, u_vss_7/VSS, ... (33 possible terminals)