fhdl/decorators: make the transform logic more idiomatic

* the transformers work on classes and instances.
  you can now do just do:

    @ResetInserter()
    @ClockDomainRenamer({"sys": "new"})
    class Foo(Module):
        pass

  or:

    a = ResetInserter()(FooModule())

* the old usage semantics still work
* the old DecorateModule is deprecated,
  ModuleDecorator has been refactored into ModuleTransformer
  (because it not only decorates things)

migen/fhdl/decorators.py

@@ -1,94 +1,114 @@
+import warnings
+
 from migen.fhdl.structure import *
 from migen.fhdl.tools import insert_reset, rename_clock_domain
 
-class ModuleDecorator:
-	def __init__(self, decorated):
-		object.__setattr__(self, "_md_decorated", decorated)
-
-	def __getattr__(self, name):
-		return getattr(self._md_decorated, name)
-
-	def __setattr__(self, name, value):
-		return setattr(self._md_decorated, name, value)
-
+class ModuleTransformer:
 	# overload this in derived classes
-	def transform_fragment(self, f):
+	def transform_instance(self, i):
 		pass
 
-	def get_fragment(self):
-		f = self._md_decorated.get_fragment()
-		self.transform_fragment(f)
-		return f
+	# overload this in derived classes
+	def transform_fragment(self, i, f):
+		pass
 
-	def __dir__(self):
-		return dir(self._md_decorated)
+	def wrap_class(self, victim):
+		class Wrapped(victim):
+			def __init__(i, *args, **kwargs):
+				victim.__init__(i, *args, **kwargs)
+				self.transform_instance(i)
 
-class DecorateModule:
-	def __init__(self, decorator, *dec_args, **dec_kwargs):
-		self.decorator = decorator
-		self.dec_args = dec_args
-		self.dec_kwargs = dec_kwargs
+			def get_fragment(i):
+				f = victim.get_fragment(i)
+				self.transform_fragment(i, f)
+				return f
 
-	def __call__(self, decorated):
-		def dfinit(dfself, *args, **kwargs):
-			self.decorator.__init__(dfself, decorated(*args, **kwargs),
-				*self.dec_args, **self.dec_kwargs)
-		typename = self.decorator.__name__ + "(" + decorated.__name__ + ")"
-		return type(typename, (self.decorator,), dict(__init__=dfinit))
+		Wrapped.__name__ = victim.__name__
+		# "{}_{}".format(self.__class__.__name__, victim.__name__)
+		return Wrapped
 
-class InsertControl(ModuleDecorator):
-	def __init__(self, control_name, decorated, clock_domains=None):
-		ModuleDecorator.__init__(self, decorated)
+	def wrap_instance(self, victim):
+		self.transform_instance(victim)
+		orig_get_fragment = victim.get_fragment
 
-		object.__setattr__(self, "_ic_control_name", control_name)
-		object.__setattr__(self, "_ic_clock_domains", clock_domains)
+		def get_fragment():
+			f = orig_get_fragment()
+			self.transform_fragment(victim, f)
+			return f
 
-		if clock_domains is None:
-			ctl = Signal(name=control_name)
-			assert(not hasattr(decorated, control_name))
-			object.__setattr__(self, control_name, ctl)
+		victim.get_fragment = get_fragment
+		return victim
+
+	def __call__(self, victim):
+		try:
+			return self.wrap_class(victim)
+		except TypeError:
+			return self.wrap_instance(victim)
+
+	@classmethod
+	def adhoc(cls, i, *args, **kwargs):
+		warnings.warn("deprecated, use the plain transformer", DeprecationWarning)
+		return cls(*args, **kwargs)(i)
+
+def DecorateModule(transformer, *args, **kwargs):
+	warnings.warn("deprecated, use the plain transformer", DeprecationWarning)
+	return transformer.__self__(*args, **kwargs)
+
+class ControlInserter(ModuleTransformer):
+	control_name = None  # override this
+
+	def __init__(self, clock_domains=None):
+		self.clock_domains = clock_domains
+
+	def transform_instance(self, i):
+		if self.clock_domains is None:
+			ctl = Signal(name=self.control_name)
+			assert not hasattr(i, self.control_name)
+			setattr(i, self.control_name, ctl)
 		else:
-			for cd in clock_domains:
-				name = control_name + "_" + cd
+			for cd in self.clock_domains:
+				name = self.control_name + "_" + cd
 				ctl = Signal(name=name)
-				assert(not hasattr(decorated, name))
-				object.__setattr__(self, name, ctl)
+				assert not hasattr(i, name)
+				setattr(i, name, ctl)
 
-	def transform_fragment(self, f):
-		control_name = self._ic_control_name
-		clock_domains = self._ic_clock_domains
-		if clock_domains is None:
+	def transform_fragment(self, i, f):
+		if self.clock_domains is None:
 			if len(f.sync) != 1:
 				raise ValueError("Control signal clock domains must be specified when module has more than one domain")
 			cdn = list(f.sync.keys())[0]
-			to_insert = [(getattr(self, control_name), cdn)]
+			to_insert = [(getattr(i, self.control_name), cdn)]
 		else:
-			to_insert = [(getattr(self, control_name+"_"+cdn), cdn) for cdn in clock_domains]
-		self.transform_fragment_insert(f, to_insert)
+			to_insert = [(getattr(i, self.control_name + "_" + cdn), cdn)
+				for cdn in clock_domains]
+		self.transform_fragment_insert(i, f, to_insert)
 
-class InsertCE(InsertControl):
-	def __init__(self, *args, **kwargs):
-		InsertControl.__init__(self, "ce", *args, **kwargs)
+class CEInserter(ControlInserter):
+	control_name = "ce"
 
-	def transform_fragment_insert(self, f, to_insert):
+	def transform_fragment_insert(self, i, f, to_insert):
 		for ce, cdn in to_insert:
 			f.sync[cdn] = [If(ce, *f.sync[cdn])]
 
-class InsertReset(InsertControl):
-	def __init__(self, *args, **kwargs):
-		InsertControl.__init__(self, "reset", *args, **kwargs)
+InsertCE = CEInserter.adhoc
 
-	def transform_fragment_insert(self, f, to_insert):
+class ResetInserter(ControlInserter):
+	control_name = "reset"
+
+	def transform_fragment_insert(self, i, f, to_insert):
 		for reset, cdn in to_insert:
 			f.sync[cdn] = insert_reset(reset, f.sync[cdn])
 
-class RenameClockDomains(ModuleDecorator):
-	def __init__(self, decorated, cd_remapping):
-		ModuleDecorator.__init__(self, decorated)
+InsertReset = ResetInserter.adhoc
+
+class ClockDomainsRenamer(ModuleTransformer):
+	def __init__(self, cd_remapping):
 		if isinstance(cd_remapping, str):
 			cd_remapping = {"sys": cd_remapping}
-		object.__setattr__(self, "_rc_cd_remapping", cd_remapping)
+		self.cd_remapping = cd_remapping
 
-	def transform_fragment(self, f):
-		for old, new in self._rc_cd_remapping.items():
+	def transform_fragment(self, i, f):
+		for old, new in self.cd_remapping.items():
 			rename_clock_domain(f, old, new)
+
+RenameClockDomains = ClockDomainsRenamer.adhoc

migen/fhdl/simplify.py

@@ -1,10 +1,10 @@
 from migen.fhdl.std import *
 from migen.fhdl.specials import _MemoryPort
-from migen.fhdl.decorators import ModuleDecorator
+from migen.fhdl.decorators import ModuleTransformer
 from migen.util.misc import gcd_multiple
 
-class FullMemoryWE(ModuleDecorator):
-	def transform_fragment(self, f):
+class FullMemoryWE(ModuleTransformer):
+	def transform_fragment(self, i, f):
 		newspecials = set()
 
 		for orig in f.specials: