code review changes per Deepashree

Signed-off-by: Cho Moon <cmoon@precisioninno.com>

Author: precisionmoon

graph/Graph.i

@@ -28,6 +28,7 @@
 #include "Graph.hh"
 #include "FuncExpr.hh"
 #include "TimingRole.hh"
+#include "search/Levelize.hh"
 #include "Liberty.hh"
 #include "Network.hh"
 #include "Clock.hh"
@@ -118,6 +119,32 @@ remove_delay_slew_annotations()
   Sta::sta()->removeDelaySlewAnnotations();
 }
 
+void
+report_levelized_drvr_vertices(int max_count)
+{
+  Sta *sta = Sta::sta();
+  sta->ensureGraph();
+  const VertexSeq &drvrs = sta->levelizedDrvrVertices();
+  Report *report = sta->report();
+  const Network *network = sta->network();
+  report->report("driver vertex count {}", drvrs.size());
+  Level prev_level = -1;
+  int n = 0;
+  for (Vertex *vertex : drvrs) {
+    Level level = vertex->level();
+    if (level < prev_level)
+      report->report("level order violated {} {} < {}",
+                     network->pathName(vertex->pin()),
+                     level, prev_level);
+    if (n < max_count)
+      report->report("{} level={}",
+                     network->pathName(vertex->pin()),
+                     level);
+    prev_level = level;
+    n++;
+  }
+}
+
 %} // inline
 
 ////////////////////////////////////////////////////////////////

include/sta/Sta.hh

@@ -1325,7 +1325,7 @@ public:
   // Ensure that the timing graph has been built.
   Graph *ensureGraph();
   void ensureClkArrivals();
-  Levelize* levelize() const { return levelize_; }
+  const VertexSeq& levelizedDrvrVertices();
 
   // Find all arc delays and vertex slews with delay calculator.
   virtual void findDelays();

search/Levelize.cc

@@ -92,6 +92,7 @@ Levelize::clear()
   loop_edges_.clear();
   max_level_ = 0;
   drvr_vertices_level_valid_ = false;
+  levelized_drvr_vertices_.clear();
 }
 
 void
@@ -548,11 +549,11 @@ Levelize::setLevel(Vertex *vertex,
 void
 Levelize::invalid()
 {
+  drvr_vertices_level_valid_ = false;
   if (levelized_) {
     debugPrint(debug_, "levelize", 1, "levels invalid");
     levelized_ = false;
     levels_valid_ = false;
-    drvr_vertices_level_valid_ = false;
   }
 }
 
@@ -563,6 +564,7 @@ Levelize::deleteVertexBefore(Vertex *vertex)
     roots_.erase(vertex);
     relevelize_from_.erase(vertex);
     drvr_vertices_level_valid_ = false;
+    levelized_drvr_vertices_.clear();
   }
 }
 
@@ -720,15 +722,19 @@ void
 Levelize::levelizeDrvrVertices()
 {
   levelized_drvr_vertices_.clear();
+  // Rough estimate: ~half of vertices are drivers
+  levelized_drvr_vertices_.reserve(graph_->vertexCount() / 2);
   VertexIterator vertex_iter(graph_);
   while (vertex_iter.hasNext()) {
     Vertex *vertex = vertex_iter.next();
     if (vertex->isDriver(network_))
       levelized_drvr_vertices_.emplace_back(vertex);
   }
   sort(levelized_drvr_vertices_,
-       [](const Vertex *a, const Vertex *b) {
-         return a->level() < b->level();
+       [this](const Vertex *a, const Vertex *b) {
+         if (a->level() != b->level())
+           return a->level() < b->level();
+         return VertexNameLess(network_)(a, b);
        });
   drvr_vertices_level_valid_ = true;
 }

search/Sta.cc

@@ -2900,6 +2900,12 @@ Sta::ensureClkArrivals()
   search_->findClkArrivals();
 }
 
+const VertexSeq&
+Sta::levelizedDrvrVertices()
+{
+  return levelize_->levelizedDrvrVertices();
+}
+
 ////////////////////////////////////////////////////////////////
 
 VertexSet &