initial work towards fleshing out package conversion

src/Convert/NestPI.hs

@@ -49,7 +49,7 @@ traverseDescriptionM (orig @ (Part extern kw lifetime name ports items)) = do
             existingPIs
     let newItems = map MIPackageItem $ Map.elems $
             Map.restrictKeys tfs neededPIs
-    return $ Part extern kw lifetime name ports (items ++ newItems)
+    return $ Part extern kw lifetime name ports (newItems ++ items)
     where
         existingPIs = execWriter $ collectModuleItemsM collectPIsM orig
         runner f = execWriter $ collectModuleItemsM f orig
@@ -97,4 +97,5 @@ piName (Decl (Variable _ _ ident _ _)) = Just ident
 piName (Decl (Parameter  _ ident   _)) = Just ident
 piName (Decl (Localparam _ ident   _)) = Just ident
 piName (Import x y) = Just $ show $ Import x y
+piName (Export   _) = Nothing
 piName (Comment  _) = Nothing

src/Convert/Package.hs

@@ -1,7 +1,32 @@
 {- sv2v
  - Author: Zachary Snow <zach@zachjs.com>
  -
- - Conversion for packages and imports
+ - Conversion for packages, exports, and imports
+ -
+ - TODO: We do not yet handle exports.
+ - TODO: The scoping rules are not being entirely followed yet.
+ - TODO: Explicit imports may introduce name conflicts because of carried items.
+ -
+ - The SystemVerilog scoping rules for exports and imports are not entirely
+ - trivial. We do not explicitly handle the "error" scenarios detailed Table
+ - 26-1 of Section 26-3 of IEEE 1800-2017. Users generally shouldn't be relying
+ - on this tool to catch and report such wild naming conflicts that are outlined
+ - there.
+ -
+ - Summary:
+ - * In scopes which have a local declaration of an identifier, that identifier
+ -   refers to that local declaration.
+ - * If there is no local declaration, the identifier refers to the imported
+ -   declaration.
+ - * If there is an explicit import of that identifier, the identifier refers to
+ -   the imported declaration.
+ - * Usages of conflicting wildcard imports are not allowed.
+ -
+ - If a package cannot be found within a file that references it (including
+ - through files it imports), we fall back to an arbitrary package with the
+ - given name, if it exists. While this isn't foolproof, some projects do rely
+ - on their toolchain to locate their packages in other files, much like modules
+ - or interfaces.
  -}
 
 module Convert.Package (convert) where
@@ -29,13 +54,23 @@ convert asts =
             where
                 packages = execWriter $
                     collectDescriptionsM collectDescriptionM $ concat curr
-                globalItems = map PackageItem $
-                    concatMap (uncurry globalPackageItems) $ Map.toList packages
-                next = map ((++) globalItems) $ map (filter shouldntRemove) $ map
-                    (traverseDescriptions $ traverseDescription packages) curr
-                shouldntRemove :: Description -> Bool
-                shouldntRemove (Package _ name _) = Map.notMember name packages
-                shouldntRemove _ = True
+                next = map (convertFile packages) curr
+
+convertFile :: Packages -> AST -> AST
+convertFile globalPackages ast =
+    (++) globalItems $
+    filter (not . isCollected) $
+    traverseDescriptions (traverseDescription packages) $
+    ast
+    where
+        globalItems = map PackageItem $
+             concatMap (uncurry globalPackageItems) $ Map.toList packages
+        localPackages = execWriter $
+             collectDescriptionsM collectDescriptionM ast
+        packages = Map.union localPackages globalPackages
+        isCollected :: Description -> Bool
+        isCollected (Package _ name _) = Map.member name localPackages
+        isCollected _ = False
 
 globalPackageItems :: Identifier -> PackageItems -> [PackageItem]
 globalPackageItems name items =
@@ -86,20 +121,30 @@ collectDescriptionM _ = return ()
 
 traverseDescription :: Packages -> Description -> Description
 traverseDescription packages description =
-    traverseModuleItems (traverseModuleItem packages) description
+    traverseModuleItems (traverseModuleItem existingItemNames packages)
+    description
+    where
+        existingItemNames = execWriter $
+            collectModuleItemsM writePIName description
+        writePIName :: ModuleItem -> Writer Idents ()
+        writePIName (MIPackageItem item) =
+            case piName item of
+                Nothing -> return ()
+                Just x -> tell $ Set.singleton x
+        writePIName _ = return ()
 
-traverseModuleItem :: Packages -> ModuleItem -> ModuleItem
-traverseModuleItem packages (MIPackageItem (Import x y)) =
+traverseModuleItem :: Idents -> Packages -> ModuleItem -> ModuleItem
+traverseModuleItem existingItemNames packages (MIPackageItem (Import x y)) =
     if Map.member x packages
         then Generate $ map (GenModuleItem . MIPackageItem) items
         else MIPackageItem $ Import x y
     where
         packageItems = packages Map.! x
-        filterer = case y of
-                Nothing -> \_ -> True
-                Just ident -> (==) ident
+        filterer itemName = case y of
+                Nothing -> Set.notMember itemName existingItemNames
+                Just ident -> ident == itemName
         items = map snd $ filter (filterer . fst) $ Map.toList packageItems
-traverseModuleItem _ item =
+traverseModuleItem _ _ item =
     (traverseExprs $ traverseNestedExprs traverseExpr) $
     (traverseStmts traverseStmt) $
     (traverseTypes traverseType) $
@@ -131,4 +176,5 @@ piName (Decl (Variable _ _ ident _ _)) = Just ident
 piName (Decl (Parameter  _ ident   _)) = Just ident
 piName (Decl (Localparam _ ident   _)) = Just ident
 piName (Import _ _) = Nothing
+piName (Export   _) = Nothing
 piName (Comment  _) = Nothing

src/Convert/Traverse.hs

@@ -564,6 +564,8 @@ traverseExprsM' strat exprMapper = moduleItemMapper
         return $ MIPackageItem $ Comment c
     moduleItemMapper (MIPackageItem (Import x y)) =
         return $ MIPackageItem $ Import x y
+    moduleItemMapper (MIPackageItem (Export x)) =
+        return $ MIPackageItem $ Export x
     moduleItemMapper (AssertionItem (mx, a)) = do
         a' <- traverseAssertionStmtsM stmtMapper a
         a'' <- traverseAssertionExprsM exprMapper a'

src/Language/SystemVerilog/AST/Description.hs

@@ -57,6 +57,7 @@ data PackageItem
     | Function (Maybe Lifetime) Type Identifier [Decl] [Stmt]
     | Task     (Maybe Lifetime)      Identifier [Decl] [Stmt]
     | Import Identifier (Maybe Identifier)
+    | Export (Maybe (Identifier, Maybe Identifier))
     | Decl Decl
     | Comment String
     deriving Eq
@@ -72,6 +73,8 @@ instance Show PackageItem where
             (showLifetime ml) x (indent $ show i)
             (indent $ unlines' $ map show b)
     show (Import x y) = printf "import %s::%s;" x (fromMaybe "*" y)
+    show (Export Nothing) = "export *::*";
+    show (Export (Just (x, y))) = printf "export %s::%s;" x (fromMaybe "*" y)
     show (Decl decl) = show decl
     show (Comment c) =
         if elem '\n' c

src/Language/SystemVerilog/Parser/Parse.y

@@ -578,6 +578,8 @@ NonDeclPackageItem :: { [PackageItem] }
   | "function" opt(Lifetime) FuncRetAndName TFItems DeclsAndStmts "endfunction" opt(Tag) { [Function $2 (fst $3) (snd $3) (map defaultFuncInput $ (map makeInput $4) ++ fst $5) (snd $5)] }
   | "task" opt(Lifetime) Identifier TFItems DeclsAndStmts "endtask" opt(Tag) { [Task $2 $3 (map defaultFuncInput $ $4 ++ fst $5) (snd $5)] }
   | "import" PackageImportItems ";" { map (uncurry Import) $2 }
+  | "export" PackageImportItems ";" { map (Export .  Just) $2 }
+  | "export" "*" "::" "*" ";"       { [Export Nothing] } -- "Nothing" being no restrictions
 
 PackageImportItems :: { [(Identifier, Maybe Identifier)] }
   : PackageImportItem                        { [$1] }

test/basic/package.sv

@@ -17,6 +17,11 @@ package D;
 endpackage
 package E;
     import D::*;
+    export D::*;
+endpackage
+package F;
+    localparam MAGIC = -42;
+    localparam PIZZAZZ = -5;
 endpackage
 module top;
     import A::FOO;
@@ -33,4 +38,28 @@ module top;
         $display("%d", E::pack(0));
         $display("%d", E::pack(1));
     end
+    import F::*;
+    initial begin
+        $display("imported MAGIC %d", MAGIC);
+        $display("imported MAGIC %d", F::MAGIC);
+        begin
+            localparam MAGIC = 42;
+            $display("local MAGIC %d", MAGIC);
+            $display("imported MAGIC %d", F::MAGIC);
+        end
+        $display("imported MAGIC %d", MAGIC);
+        $display("imported MAGIC %d", F::MAGIC);
+    end
+    localparam PIZZAZZ = -6;
+    initial begin
+        $display("local PIZZAZZ %d", PIZZAZZ);
+        $display("imported PIZZAZZ %d", F::PIZZAZZ);
+        begin
+            localparam PIZZAZZ = -7;
+            $display("shadowed local PIZZAZZ %d", PIZZAZZ);
+            $display("imported PIZZAZZ %d", F::PIZZAZZ);
+        end
+        $display("local PIZZAZZ %d", PIZZAZZ);
+        $display("imported PIZZAZZ %d", F::PIZZAZZ);
+    end
 endmodule

test/basic/package.v

@@ -25,4 +25,20 @@ module top;
         $display("%d", E_pack(0));
         $display("%d", E_pack(1));
     end
+    initial begin
+        $display("imported MAGIC %d", -42);
+        $display("imported MAGIC %d", -42);
+        $display("local MAGIC %d", +42);
+        $display("imported MAGIC %d", -42);
+        $display("imported MAGIC %d", -42);
+        $display("imported MAGIC %d", -42);
+    end
+    initial begin
+        $display("local PIZZAZZ %d", -6);
+        $display("imported PIZZAZZ %d", -5);
+        $display("shadowed local PIZZAZZ %d", -7);
+        $display("imported PIZZAZZ %d", -5);
+        $display("local PIZZAZZ %d", -6);
+        $display("imported PIZZAZZ %d", -5);
+    end
 endmodule