grt: add function to find clock nets

Signed-off-by: Eder Monteiro <emrmonteiro@precisioninno.com>

Author: eder-matheus

src/grt/include/grt/GlobalRouter.h

@@ -438,6 +438,8 @@ class GlobalRouter
   void computeCapacities(int max_layer);
   void findTrackPitches(int max_layer);
   std::vector<Net*> findNets(bool init_clock_nets);
+  void findClockNets(const std::vector<Net*>& nets,
+                     std::set<odb::dbNet*>& clock_nets);
   void computeObstructionsAdjustments();
   void findLayerExtensions(std::vector<int>& layer_extensions);
   int findObstructions(odb::Rect& die_area);

src/grt/src/GlobalRouter.cpp

@@ -3794,6 +3794,16 @@ std::vector<Net*> GlobalRouter::findNets(bool init_clock_nets)
   return nets;
 }
 
+void GlobalRouter::findClockNets(const std::vector<Net*>& nets,
+                                 std::set<odb::dbNet*>& clock_nets)
+{
+  for (Net* net : nets) {
+    if (net->isClockNet()) {
+      clock_nets.insert(net->getDbNet());
+    }
+  }
+}
+
 Net* GlobalRouter::addNet(odb::dbNet* db_net)
 {
   if (!db_net->getSigType().isSupply() && !db_net->isSpecial()