+ -> FlattenState ([SignalMap], SignalMap)
+
+flattenExpr binds lam@(Lam b expr) = do
+ -- Find the type of the binder
+ let (arg_ty, _) = Type.splitFunTy (CoreUtils.exprType lam)
+ -- Create signal names for the binder
+ defs <- genSignals arg_ty
+ let binds' = (b, Left defs):binds
+ (args, res) <- flattenExpr binds' expr
+ return (defs : args, res)
+
+flattenExpr binds (Var id) =
+ case bind of
+ Left sig_use -> return ([], sig_use)
+ Right _ -> error "Higher order functions not supported."
+ where
+ bind = Maybe.fromMaybe
+ (error $ "Argument " ++ Name.getOccString id ++ " is unknown")
+ (lookup id binds)
+
+flattenExpr binds app@(App _ _) = do
+ -- Is this a data constructor application?
+ case CoreUtils.exprIsConApp_maybe app of
+ -- Is this a tuple construction?
+ Just (dc, args) -> if DataCon.isTupleCon dc
+ then
+ flattenBuildTupleExpr binds (dataConAppArgs dc args)
+ else
+ error $ "Data constructors other than tuples not supported: " ++ (showSDoc $ ppr app)
+ otherwise ->
+ -- Normal function application
+ let ((Var f), args) = collectArgs app in
+ flattenApplicationExpr binds (CoreUtils.exprType app) f args
+ where
+ flattenBuildTupleExpr binds args = do
+ -- Flatten each of our args
+ flat_args <- (State.mapM (flattenExpr binds) args)
+ -- Check and split each of the arguments
+ let (_, arg_ress) = unzip (zipWith checkArg args flat_args)
+ let res = Tuple arg_ress
+ return ([], res)
+
+ -- | Flatten a normal application expression
+ flattenApplicationExpr binds ty f args = do
+ -- Find the function to call
+ let func = appToHsFunction ty f args
+ -- Flatten each of our args
+ flat_args <- (State.mapM (flattenExpr binds) args)
+ -- Check and split each of the arguments
+ let (_, arg_ress) = unzip (zipWith checkArg args flat_args)
+ -- Generate signals for our result
+ res <- genSignals ty
+ -- Create the function application
+ let app = FApp {
+ appFunc = func,
+ appArgs = arg_ress,
+ appRes = res
+ }
+ addDef app
+ return ([], res)
+ -- | Check a flattened expression to see if it is valid to use as a
+ -- function argument. The first argument is the original expression for
+ -- use in the error message.
+ checkArg arg flat =
+ let (args, res) = flat in
+ if not (null args)
+ then error $ "Passing lambda expression or function as a function argument not supported: " ++ (showSDoc $ ppr arg)
+ else flat
+
+flattenExpr binds l@(Let (NonRec b bexpr) expr) = do
+ (b_args, b_res) <- flattenExpr binds bexpr
+ if not (null b_args)
+ then
+ error $ "Higher order functions not supported in let expression: " ++ (showSDoc $ ppr l)
+ else
+ let binds' = (b, Left b_res) : binds in
+ flattenExpr binds' expr
+
+flattenExpr binds l@(Let (Rec _) _) = error $ "Recursive let definitions not supported: " ++ (showSDoc $ ppr l)
+
+flattenExpr binds expr@(Case (Var v) b _ alts) =
+ case alts of
+ [alt] -> flattenSingleAltCaseExpr binds var b alt
+ otherwise -> flattenMultipleAltCaseExpr binds var b alts
+ where
+ var = Maybe.fromMaybe
+ (error $ "Case expression uses unknown scrutinee " ++ Name.getOccString v)
+ (lookup v binds)
+
+ flattenSingleAltCaseExpr ::
+ BindMap
+ -- A list of bindings in effect
+ -> BindValue -- The scrutinee
+ -> CoreBndr -- The binder to bind the scrutinee to
+ -> CoreAlt -- The single alternative
+ -> FlattenState ( [SignalMap], SignalMap) -- See expandExpr
+
+ flattenSingleAltCaseExpr binds var b alt@(DataAlt datacon, bind_vars, expr) =
+ if DataCon.isTupleCon datacon
+ then
+ let
+ -- Unpack the scrutinee (which must be a variable bound to a tuple) in
+ -- the existing bindings list and get the portname map for each of
+ -- it's elements.
+ Left (Tuple tuple_sigs) = var
+ -- TODO include b in the binds list
+ -- Merge our existing binds with the new binds.
+ binds' = (zip bind_vars (map Left tuple_sigs)) ++ binds
+ in
+ -- Expand the expression with the new binds list
+ flattenExpr binds' expr
+ else
+ if null bind_vars
+ then
+ -- DataAlts without arguments don't need processing
+ -- (flattenMultipleAltCaseExpr will have done this already).
+ flattenExpr binds expr
+ else
+ error $ "Dataconstructors other than tuple constructors cannot have binder arguments in case pattern of alternative: " ++ (showSDoc $ ppr alt)
+ flattenSingleAltCaseExpr _ _ _ alt = error $ "Case patterns other than data constructors not supported in case alternative: " ++ (showSDoc $ ppr alt)
+
+ flattenMultipleAltCaseExpr ::
+ BindMap
+ -- A list of bindings in effect
+ -> BindValue -- The scrutinee
+ -> CoreBndr -- The binder to bind the scrutinee to
+ -> [CoreAlt] -- The alternatives
+ -> FlattenState ( [SignalMap], SignalMap) -- See expandExpr
+
+ flattenMultipleAltCaseExpr binds var b (a:a':alts) = do
+ (args, res) <- flattenSingleAltCaseExpr binds var b a
+ (args', res') <- flattenMultipleAltCaseExpr binds var b (a':alts)
+ case a of
+ (DataAlt datacon, bind_vars, expr) -> do
+ let tycon = DataCon.dataConTyCon datacon
+ let tyname = TyCon.tyConName tycon
+ case Name.getOccString tyname of
+ -- TODO: Do something more robust than string matching
+ "Bit" -> do
+ -- The scrutinee must be a single signal
+ let Left (Single sig) = var
+ let dcname = DataCon.dataConName datacon
+ let lit = case Name.getOccString dcname of "High" -> "'1'"; "Low" -> "'0'"
+ -- Create a signal that contains a boolean
+ boolsigid <- genSignalId SigInternal TysWiredIn.boolTy
+ let expr = EqLit sig lit
+ addDef (UncondDef (Right expr) boolsigid)
+ -- Create conditional assignments of either args/res or
+ -- args'/res based on boolsigid, and return the result.
+ our_args <- zipWithM (mkConditionals boolsigid) args args'
+ our_res <- mkConditionals boolsigid res res'
+ return (our_args, our_res)
+ otherwise ->
+ error $ "Type " ++ (Name.getOccString tyname) ++ " not supported in multiple alternative case expressions."
+ otherwise ->
+ error $ "Case patterns other than data constructors not supported in case alternative: " ++ (showSDoc $ ppr a)
+ where
+ -- Select either the first or second signal map depending on the value
+ -- of the first argument (True == first map, False == second map)
+ mkConditionals :: SignalId -> SignalMap -> SignalMap -> FlattenState SignalMap
+ mkConditionals boolsigid true false = do
+ let zipped = zipValueMaps true false
+ Traversable.mapM (mkConditional boolsigid) zipped