write_sdc crash after delete instance resolves #248

commit 3b7eba13dcfc90dc8f8b0b6c3959c9253c302eae
Author: James Cherry <cherry@parallaxsw.com>
Date:   Thu May 29 14:05:39 2025 -0700

    write_sdc crash after delete instance resolves #248

    Signed-off-by: James Cherry <cherry@parallaxsw.com>

Signed-off-by: James Cherry <cherry@parallaxsw.com>

include/sta/ExceptionPath.hh

@@ -119,6 +119,9 @@ public:
 			       ExceptionThruSeq *thrus,
 			       ExceptionTo *to,
 			       bool own_pts) = 0;
+  void deleteInstance(const Instance *inst,
+                      const Network *network);
+
   // Default handlers.
   virtual bool useEndClk() const { return false; }
   virtual int pathMultiplier() const { return 0; }
@@ -414,14 +417,14 @@ public:
 			       Network *) {}
   virtual void disconnectPinBefore(const Pin *,
 				   Network *) {}
+  void deleteInstance(const Instance *inst,
+                      const Network *network);
 
 protected:
   virtual void findHash(const Network *network);
 
   void deletePin(const Pin *pin,
                  const Network *network);
-  void deleteInstance(const Instance *inst,
-                      const Network *network);
   virtual const char *cmdKeyword() const = 0;
 
   PinSet *pins_;
@@ -536,6 +539,8 @@ public:
 			       Network *network);
   virtual void disconnectPinBefore(const Pin *pin,
 				   Network *network);
+  void deleteInstance(const Instance *inst,
+                      const Network *network);
 
 protected:
   void findHash(const Network *network);
@@ -553,8 +558,6 @@ protected:
   void deleteEdge(const EdgePins &edge);
   void deleteNet(const Net *net,
                  const Network *network);
-  void deleteInstance(const Instance *inst,
-                      const Network *network);
   void makeAllEdges(const Network *network);
   void makePinEdges(const Network *network);
   void makeNetEdges(const Network *network);

include/sta/Sdc.hh

@@ -216,6 +216,7 @@ public:
   // Build data structures for search.
   void searchPreamble();
   void deleteNetBefore(const Net *net);
+  void deleteInstanceBefore(const Instance *inst);
 
   // SWIG sdc interface.
   PortSeq allInputs(bool no_clks);

sdc/ExceptionPath.cc

@@ -458,6 +458,20 @@ thrusIntersectPts(ExceptionThruSeq *thrus1,
   return true;
 }
 
+void
+ExceptionPath::deleteInstance(const Instance *inst,
+                              const Network *network)
+{
+  if (from_)
+    from_->deleteInstance(inst, network);
+  if (thrus_) {
+    for (ExceptionThru *thru : *thrus_)
+      thru->deleteInstance(inst, network);
+  }
+  if (to_)
+    to_->deleteInstance(inst, network);
+}
+
 ////////////////////////////////////////////////////////////////
 
 PathDelay::PathDelay(ExceptionFrom *from,

sdc/Sdc.cc

@@ -363,6 +363,25 @@ Sdc::deleteNetBefore(const Net *net)
   }
 }
 
+// see Sdc::isConstrained
+void
+Sdc::deleteInstanceBefore(const Instance *inst)
+{
+  instance_pvt_maps_[MinMax::minIndex()].erase(inst);
+  instance_pvt_maps_[MinMax::maxIndex()].erase(inst);
+  inst_derating_factors_.erase(inst);
+  inst_clk_gating_check_map_.erase(inst);
+  disabled_inst_ports_.erase(inst);
+  inst_latch_borrow_limit_map_.erase(inst);
+  inst_min_pulse_width_map_.erase(inst);
+
+  for (ExceptionPath *exception : exceptions_)
+    exception->deleteInstance(inst, network_);
+  first_from_inst_exceptions_.erase(inst);
+  first_thru_inst_exceptions_.erase(inst);
+  first_to_inst_exceptions_.erase(inst);
+}
+
 void
 Sdc::makeCornersBefore()
 {

search/Sta.cc

@@ -4579,6 +4579,7 @@ void
 Sta::deleteLeafInstanceBefore(const Instance *inst)
 {
   sim_->deleteInstanceBefore(inst);
+  sdc_->deleteInstanceBefore(inst);
 }
 
 void