Make casesimpl support multiple-alt cases with fields.

[matthijs/master-project/cλash.git] / clash / CLasH / Utils / Core / CoreTools.hs

diff --git a/clash/CLasH/Utils/Core/CoreTools.hs b/clash/CLasH/Utils/Core/CoreTools.hs
index 2bb688bb7f0c023a1d9b7986a97eb581f22b808c..e98aec6a090ab2abc77d15251ac25850054c3185 100644 (file)
--- a/clash/CLasH/Utils/Core/CoreTools.hs
+++ b/clash/CLasH/Utils/Core/CoreTools.hs
@@ -438,26 +438,34 @@ genUnique subst bndr = do
   let subst' = VarEnv.extendVarEnv subst bndr bndr'
   return (subst', bndr')
 
--- Create a "selector" case that selects the ith field from a datacon
-mkSelCase :: CoreSyn.CoreExpr -> Int -> TranslatorSession CoreSyn.CoreExpr
-mkSelCase scrut i = do
-  let scrut_ty = CoreUtils.exprType scrut
+-- Create a "selector" case that selects the ith field from dc_ith
+-- datacon
+mkSelCase :: CoreSyn.CoreExpr -> Int -> Int -> TranslatorSession CoreSyn.CoreExpr
+mkSelCase scrut dc_i i = do
   case Type.splitTyConApp_maybe scrut_ty of
     -- The scrutinee should have a type constructor. We keep the type
     -- arguments around so we can instantiate the field types below
-    Just (tycon, tyargs) -> case TyCon.tyConDataCons tycon of
+    Just (tycon, tyargs) -> case TyCon.tyConDataCons_maybe tycon of
       -- The scrutinee type should have a single dataconstructor,
       -- otherwise we can't construct a valid selector case.
-      [datacon] -> do
-        let field_tys = DataCon.dataConInstOrigArgTys datacon tyargs
-        -- Create a list of wild binders for the fields we don't want
-        let wildbndrs = map MkCore.mkWildBinder field_tys
-        -- Create a single binder for the field we want
-        sel_bndr <- mkInternalVar "sel" (field_tys!!i)
-        -- Create a wild binder for the scrutinee
-        let scrut_bndr = MkCore.mkWildBinder scrut_ty
-        -- Create the case expression
-        let binders = take i wildbndrs ++ [sel_bndr] ++ drop (i+1) wildbndrs
-        return $ CoreSyn.Case scrut scrut_bndr scrut_ty [(CoreSyn.DataAlt datacon, binders, CoreSyn.Var sel_bndr)]
-      dcs -> error $ "CoreTools.mkSelCase: Scrutinee type must have exactly one datacon. Extracting element " ++ (show i) ++ " from '" ++ pprString scrut ++ "' Datacons: " ++ (show dcs) ++ " Type: " ++ (pprString scrut_ty)
-    Nothing -> error $ "CoreTools.mkSelCase: Creating extractor case, but scrutinee has no tycon? Extracting element " ++ (show i) ++ " from '" ++ pprString scrut ++ "'" ++ " Type: " ++ (pprString scrut_ty)
+      Just dcs | i < 0 || i >= length dcs -> error $ "\nCoreTools.mkSelCase: Creating extractor case, but datacon index is invalid." ++ error_msg
+               | otherwise -> do
+        let datacon = (dcs!!dc_i)
+        let field_tys = DataCon.dataConInstOrigArgTys datacon  tyargs
+        if i < 0 || i >= length field_tys
+          then error $ "\nCoreTools.mkSelCase: Creating extractor case, but field index is invalid." ++ error_msg
+          else do
+            -- Create a list of wild binders for the fields we don't want
+            let wildbndrs = map MkCore.mkWildBinder field_tys
+            -- Create a single binder for the field we want
+            sel_bndr <- mkInternalVar "sel" (field_tys!!i)
+            -- Create a wild binder for the scrutinee
+            let scrut_bndr = MkCore.mkWildBinder scrut_ty
+            -- Create the case expression
+            let binders = take i wildbndrs ++ [sel_bndr] ++ drop (i+1) wildbndrs
+            return $ CoreSyn.Case scrut scrut_bndr scrut_ty [(CoreSyn.DataAlt datacon, binders, CoreSyn.Var sel_bndr)]
+      Nothing -> error $ "CoreTools.mkSelCase: Creating extractor case, but scrutinee has no datacons?" ++ error_msg
+    Nothing -> error $ "CoreTools.mkSelCase: Creating extractor case, but scrutinee has no tycon?" ++ error_msg
+  where
+    scrut_ty = CoreUtils.exprType scrut
+    error_msg = " Extracting element " ++ (show i) ++ " from datacon " ++ (show dc_i) ++ " from '" ++ pprString scrut ++ "'" ++ " Type: " ++ (pprString scrut_ty)