core: allow re-creation of Core object, do not use _allow_registration global variable

artiq/coredevice/core.py

@@ -56,15 +56,16 @@ class Core:
         self.core = self
         self.comm.core = self
         self.target = target
+        self.analyzed = False
         self.compiler = nac3artiq.NAC3(target)
 
     def close(self):
         self.comm.close()
 
     def compile(self, method, args, kwargs, embedding_map, file_output=None):
-        if core_language._allow_registration:
+        if not self.analyzed:
             self.compiler.analyze(core_language._registered_functions, core_language._registered_classes)
-            core_language._allow_registration = False
+            self.analyzed = True
 
         if hasattr(method, "__self__"):
             obj = method.__self__

artiq/language/core.py

@@ -46,18 +46,15 @@ def ceil64(x):
     return ceil(x)
 
 
-_allow_registration = True
 # Delay NAC3 analysis until all referenced variables are supposed to exist on the CPython side.
 _registered_functions = set()
 _registered_classes = set()
 
 def _register_function(fun):
-    assert _allow_registration
     import_cache.add_module_to_cache(getmodule(fun))
     _registered_functions.add(fun)
 
 def _register_class(cls):
-    assert _allow_registration
     import_cache.add_module_to_cache(getmodule(cls))
     _registered_classes.add(cls)