substitution conversion for size casts (closes #27)

src/Convert.hs

@@ -22,7 +22,6 @@ import qualified Convert.Interface
 import qualified Convert.IntTypes
 import qualified Convert.KWArgs
 import qualified Convert.Logic
-import qualified Convert.Mux
 import qualified Convert.NamedBlock
 import qualified Convert.NestPI
 import qualified Convert.Package
@@ -30,6 +29,7 @@ import qualified Convert.PackedArray
 import qualified Convert.ParamType
 import qualified Convert.RemoveComments
 import qualified Convert.Return
+import qualified Convert.Simplify
 import qualified Convert.StarPort
 import qualified Convert.StmtBlock
 import qualified Convert.Stream
@@ -53,9 +53,9 @@ phases excludes =
     , Convert.EmptyArgs.convert
     , Convert.IntTypes.convert
     , Convert.KWArgs.convert
-    , Convert.Mux.convert
     , Convert.PackedArray.convert
     , Convert.ParamType.convert
+    , Convert.Simplify.convert
     , Convert.StarPort.convert
     , Convert.StmtBlock.convert
     , Convert.Stream.convert

src/Convert/Enum.hs

@@ -95,7 +95,7 @@ toItem ((mr, x), v) =
     where
         v' = if mr == Nothing
                 then simplify v
-                else sizedExpr x r (simplify v)
+                else sizedExpr x (rangeSize r) (simplify v)
         rs = maybe [] (\a -> [a]) mr
         r = defaultRange mr
         itemType = Implicit Unspecified rs

src/Convert/Mux.hs → src/Convert/Simplify.hs

 {- sv2v
  - Author: Zachary Snow <zach@zachjs.com>
  -
- - Elaboration of ternary expressions where the condition references a
- - localparam.
+ - Elaboration of size casts and ternary expressions where the condition
+ - references a localparam.
  -
  - Our conversions generate a lot of ternary expressions. This conversion
  - attempts to make the code output a bit cleaner. Note that we can only do this
@@ -14,7 +14,7 @@
  - expression to be simplified further.
  -}
 
-module Convert.Mux (convert) where
+module Convert.Simplify (convert) where
 
 import Control.Monad.State
 import qualified Data.Map.Strict as Map
@@ -48,18 +48,25 @@ traverseExprM :: Expr -> State Info Expr
 traverseExprM = traverseNestedExprsM $ stately convertExpr
 
 convertExpr :: Info -> Expr -> Expr
+convertExpr info (Cast (Right c) e) =
+    if sized == e
+        then Cast (Right c') e
+        else sized
+    where
+        c' = simplify $ traverseNestedExprs (substitute info) (simplify c)
+        sized = sizedExpr "" c' e
 convertExpr info (Mux cc aa bb) =
     if before == after
         then Mux cc aa bb
         else simplify $ Mux after aa bb
     where
-        before = traverseNestedExprs substitute (simplify cc)
+        before = traverseNestedExprs (substitute info) (simplify cc)
         after = simplify before
-        substitute :: Expr -> Expr
-        substitute (Ident x) =
-            case Map.lookup x info of
-                Nothing -> Ident x
-                Just e-> e
-        substitute other = other
 convertExpr _ other = other
 
+substitute :: Info -> Expr -> Expr
+substitute info (Ident x) =
+    case Map.lookup x info of
+        Nothing -> Ident x
+        Just e -> e
+substitute _ other = other

src/Convert/Typedef.hs

@@ -57,6 +57,7 @@ convertDescription globalTypes description =
                 else Right $ Ident x
         convertTypeOrExpr other = other
         convertExpr :: Expr -> Expr
+        convertExpr (Cast v e) = Cast (convertTypeOrExpr v) e
         convertExpr (Bits v) = Bits $ convertTypeOrExpr v
         convertExpr other = other
         convertModuleItem :: ModuleItem -> ModuleItem

src/Language/SystemVerilog/AST/Expr.hs

@@ -217,14 +217,14 @@ endianCondRange r r1 r2 =
     )
 
 -- attempts to make a number literal have an explicit size
-sizedExpr :: Identifier -> Range -> Expr -> Expr
-sizedExpr x r (Number n) =
+sizedExpr :: Identifier -> Expr -> Expr -> Expr
+sizedExpr x s (Number n) =
     if size /= show resSize
         then error $ "literal " ++ show n ++ " for " ++ show x
                 ++ " doesn't have size " ++ show size
         else Number res
     where
-        Number size = simplify $ rangeSize r
+        Number size = simplify s
         unticked = case n of
             '\'' : rest -> rest
             rest -> rest

src/Language/SystemVerilog/Parser/Parse.y

@@ -1021,8 +1021,8 @@ Expr :: { Expr }
   | Expr "?" Expr ":" Expr      { Mux $1 $3 $5 }
   | CastingType "'" "(" Expr ")" { Cast (Left            $1) $4 }
   | Number      "'" "(" Expr ")" { Cast (Right $ Number  $1) $4 }
-  |                 Identifier  "'" "(" Expr ")" { Cast (Left $ Alias (Nothing) $1 []) $4 }
-  | Identifier "::" Identifier  "'" "(" Expr ")" { Cast (Left $ Alias (Just $1) $3 []) $6 }
+  |                 Identifier  "'" "(" Expr ")" { Cast (Right $ Ident   $1   ) $4 }
+  | Identifier "::" Identifier  "'" "(" Expr ")" { Cast (Right $ PSIdent $1 $3) $6 }
   | Expr "." Identifier         { Dot $1 $3 }
   | "'" "{" PatternItems "}"    { Pattern $3 }
   | "{" StreamOp StreamSize Concat "}" { Stream $2 $3           $4 }

sv2v.cabal

@@ -66,7 +66,6 @@ executable sv2v
     Convert.IntTypes
     Convert.KWArgs
     Convert.Logic
-    Convert.Mux
     Convert.NamedBlock
     Convert.NestPI
     Convert.Package
@@ -74,6 +73,7 @@ executable sv2v
     Convert.ParamType
     Convert.RemoveComments
     Convert.Return
+    Convert.Simplify
     Convert.StarPort
     Convert.StmtBlock
     Convert.Stream

test/basic/size_cast.sv

+module top;
+    localparam BW = 3;
+    logic [2:0] test;
+    assign test = BW'(0);
+    initial $display(test);
+endmodule

test/basic/size_cast.v

+module top;
+    localparam BW = 3;
+    wire [2:0] test;
+    assign test = 0;
+    initial $display(test);
+endmodule