defer elaboration of void functions

src/Convert/EmptyArgs.hs

@@ -30,14 +30,16 @@ convertDescription description@Part{} =
 convertDescription other = other
 
 traverseFunctionsM :: ModuleItem -> Writer Idents ModuleItem
-traverseFunctionsM (MIPackageItem (Function ml t f decls stmts)) = do
+traverseFunctionsM item@(MIPackageItem (Function _ Void _ _ _)) =
+    return item
+traverseFunctionsM (MIPackageItem (Function l t f decls stmts)) = do
     decls' <-
         if any isInput decls
             then return decls
             else do
                 tell $ Set.singleton f
                 return $ dummyDecl : decls
-    return $ MIPackageItem $ Function ml t f decls' stmts
+    return $ MIPackageItem $ Function l t f decls' stmts
     where
         dummyType = IntegerVector TReg Unspecified []
         dummyDecl = Variable Input dummyType "_sv2v_unused" [] Nil

src/Convert/FuncRet.hs

 {- sv2v
  - Author: Zachary Snow <zach@zachjs.com>
  -
- - Conversion which makes function `logic` and `reg` return types implicit
+ - Conversion which makes function `logic` and `reg` return types implicit and
+ - converts `void` functions to tasks
  -
  - Verilog-2005 restricts function return types to `integer`, `real`,
  - `realtime`, `time`, and implicit signed/dimensioned types.
@@ -16,6 +17,8 @@ convert :: [AST] -> [AST]
 convert = map $ traverseDescriptions $ traverseModuleItems convertFunction
 
 convertFunction :: ModuleItem -> ModuleItem
+convertFunction (MIPackageItem (Function ml Void f decls stmts)) =
+    MIPackageItem $ Task ml f decls stmts
 convertFunction (MIPackageItem (Function ml t f decls stmts)) =
     MIPackageItem $ Function ml t' f decls stmts
     where

src/Convert/FuncRoutine.hs

@@ -32,6 +32,7 @@ convertDescription description@Part{} =
 convertDescription other = other
 
 collectFunctionsM :: ModuleItem -> Writer Idents ()
+collectFunctionsM (MIPackageItem (Function _ Void _ _ _)) = return ()
 collectFunctionsM (MIPackageItem (Function _ _ f _ _)) =
     tell $ Set.singleton f
 collectFunctionsM _ = return ()

src/Convert/Traverse.hs

@@ -834,6 +834,7 @@ traverseSinglyNestedTypesM mapper = tm
         tm (UnpackedType t r) = do
             t' <- mapper t
             return $ UnpackedType t' r
+        tm Void = return Void
 
 traverseSinglyNestedTypes :: Mapper Type -> Mapper Type
 traverseSinglyNestedTypes = unmonad traverseSinglyNestedTypesM

src/Language/SystemVerilog/AST/Type.hs

@@ -52,6 +52,7 @@ data Type
     | TypeOf Expr
     | TypedefRef Expr
     | UnpackedType Type [Range] -- used internally
+    | Void
     deriving Eq
 
 instance Show Type where
@@ -74,6 +75,7 @@ instance Show Type where
     show (TypeOf expr) = printf "type(%s)" (show expr)
     show (UnpackedType t rs) = printf "UnpackedType(%s, %s)" (show t) (showRanges rs)
     show (TypedefRef e) = show e
+    show Void = "void"
 
 showFields :: [Field] -> String
 showFields items = itemsStr
@@ -102,6 +104,7 @@ typeRanges typ =
         NonInteger    kw       -> (nullRange $ NonInteger  kw   , [])
         TypeOf            expr -> (nullRange $ TypeOf       expr, [])
         TypedefRef        expr -> (nullRange $ TypedefRef   expr, [])
+        Void                   -> (nullRange Void               , [])
 
 nullRange :: Type -> ([Range] -> Type)
 nullRange t [] = t

src/Language/SystemVerilog/Parser/Parse.y

@@ -924,7 +924,6 @@ ImportOrExport :: { [PackageItem] }
   | "export" "*" "::" "*" ";"       { [Export "" ""] }
 TaskOrFunction :: { PackageItem }
   : "function" Lifetime FuncRetAndName    TFItems DeclsAndStmts endfunction StrTag {% checkTag (snd $3) $7 $ Function $2 (fst $3) (snd $3) (map makeInput $4 ++ fst $5) (snd $5) }
-  | "function" Lifetime "void" Identifier TFItems DeclsAndStmts endfunction StrTag {% checkTag $4       $8 $ Task     $2 $4                ($5 ++ fst $6) (snd $6) }
   | "task"     Lifetime Identifier        TFItems DeclsAndStmts endtask     StrTag {% checkTag $3       $7 $ Task     $2 $3                ($4 ++ fst $5) (snd $5) }
 Typedef :: { Decl }
   : "typedef" Type Identifier ";" { ParamType Localparam $3 $2 }
@@ -965,7 +964,6 @@ OptDPIImportProperty :: { DPIImportProperty }
 
 DPITFProto :: { (Type, Identifier, [Decl]) }
   : "function" FuncRetAndName    TFItems { (fst $2     , snd $2, $3) }
-  | "function" "void" Identifier TFItems { (UnknownType,     $3, $4) }
   | "task"     Identifier        TFItems { (UnknownType,     $2, $3) }
 
 Directive :: { String }
@@ -995,6 +993,7 @@ FuncRetAndName :: { (Type, Identifier) }
   | Signing                    Identifier { (Implicit $1          [], $2) }
   |         DimensionsNonEmpty Identifier { (Implicit Unspecified $1, $2) }
   | Signing DimensionsNonEmpty Identifier { (Implicit $1          $2, $3) }
+  | "void"                     Identifier { (Void                   , $2) }
 
 AlwaysKW :: { AlwaysKW }
   : "always"       { Always      }