sim: ensure clean IPC shutdown

examples/sim/fir.py

@@ -66,6 +66,7 @@ def main():
 		fragment = autofragment.from_local()
 		sim = Simulator(fragment, Runner())
 		sim.run(100)
+		del sim
 		in_signals += tb.inputs
 		out_signals += tb.outputs
 	

migen/sim/generic.py

@@ -158,6 +158,9 @@ class Simulator:
 			for k, v in value.items():
 				self.multiwrite(getattr(obj, k), v)
 
+	def __del__(self):
+		del self.ipc
+		del self.sim_runner
 
 # Contrary to multiread/multiwrite, Proxy fetches the necessary signals only and
 # immediately forwards writes into the simulation.