From 4ded2a598d8827bea0fcd9264e5af3c7846654dc Mon Sep 17 00:00:00 2001
From: Zachary Snow <zach@zachjs.com>
Date: Sun, 15 Aug 2021 12:25:32 -0700
Subject: [PATCH] apply implicit port directions to tasks and functions

---
 .../SystemVerilog/Parser/ParseDecl.hs         | 37 ++++++++++---------
 test/core/task_implicit_dir.sv                | 19 ++++++++++
 test/core/task_implicit_dir.v                 | 21 +++++++++++
 3 files changed, 59 insertions(+), 18 deletions(-)
 create mode 100644 test/core/task_implicit_dir.sv
 create mode 100644 test/core/task_implicit_dir.v

diff --git a/src/Language/SystemVerilog/Parser/ParseDecl.hs b/src/Language/SystemVerilog/Parser/ParseDecl.hs
index 6767280..5012e0a 100644
--- a/src/Language/SystemVerilog/Parser/ParseDecl.hs
+++ b/src/Language/SystemVerilog/Parser/ParseDecl.hs
@@ -101,23 +101,6 @@ parseDTsAsPortDecls' pieces =
 
         pieces' = filter (not . isAttr) pieces
 
-        propagateDirections :: Direction -> [Decl] -> [Decl]
-        propagateDirections dir (decl@(Variable _ InterfaceT{} _ _ _) : decls) =
-            decl : propagateDirections dir decls
-        propagateDirections lastDir (Variable currDir t x a e : decls) =
-            decl : propagateDirections dir decls
-            where
-                decl = Variable dir t x a e
-                dir = if currDir == Local then lastDir else currDir
-        propagateDirections lastDir (Net currDir n s t x a e : decls) =
-            decl : propagateDirections dir decls
-            where
-                decl = Net dir n s t x a e
-                dir = if currDir == Local then lastDir else currDir
-        propagateDirections dir (decl : decls) =
-            decl : propagateDirections dir decls
-        propagateDirections _ [] = []
-
         portNames :: [Decl] -> [Identifier]
         portNames = filter (not . null) . map portName
         portName :: Decl -> Identifier
@@ -141,6 +124,24 @@ parseDTsAsPortDecls' pieces =
         wrapDecl :: [Attr] -> Decl -> ModuleItem
         wrapDecl attrs decl = foldr MIAttr (MIPackageItem $ Decl decl) attrs
 
+-- internal utility for carying forward port directions in a port list
+propagateDirections :: Direction -> [Decl] -> [Decl]
+propagateDirections dir (decl@(Variable _ InterfaceT{} _ _ _) : decls) =
+    decl : propagateDirections dir decls
+propagateDirections lastDir (Variable currDir t x a e : decls) =
+    decl : propagateDirections dir decls
+    where
+        decl = Variable dir t x a e
+        dir = if currDir == Local then lastDir else currDir
+propagateDirections lastDir (Net currDir n s t x a e : decls) =
+    decl : propagateDirections dir decls
+    where
+        decl = Net dir n s t x a e
+        dir = if currDir == Local then lastDir else currDir
+propagateDirections dir (decl : decls) =
+    decl : propagateDirections dir decls
+propagateDirections _ [] = []
+
 -- internal utility for a simple list of port identifiers
 parseDTsAsIdents :: [DeclToken] -> Maybe [Identifier]
 parseDTsAsIdents [DTIdent _ x, DTEnd _ _] = Just [x]
@@ -235,7 +236,7 @@ parseDTsAsIntantiation l0 delimTok =
 
 -- [PUBLIC]: parser for comma-separated task/function port declarations
 parseDTsAsTFDecls :: [DeclToken] -> [Decl]
-parseDTsAsTFDecls = parseDTsAsDecls ModeDefault
+parseDTsAsTFDecls = propagateDirections Input . parseDTsAsDecls ModeDefault
 
 
 -- [PUBLIC]; used for "single" declarations, i.e., declarations appearing
diff --git a/test/core/task_implicit_dir.sv b/test/core/task_implicit_dir.sv
new file mode 100644
index 0000000..610b3ff
--- /dev/null
+++ b/test/core/task_implicit_dir.sv
@@ -0,0 +1,19 @@
+module top;
+    task t(
+        integer inp,
+        output byte out1,
+        shortint out2
+    );
+        $display("t(inp = %0d)", inp);
+        out1 = inp;
+        out2 = inp;
+    endtask
+    initial begin
+        integer a;
+        byte b;
+        shortint c;
+        a = 5;
+        t(a, b, c);
+        $display("a = %0d, b = %0d, c = %0d", a, b, c);
+    end
+endmodule
diff --git a/test/core/task_implicit_dir.v b/test/core/task_implicit_dir.v
new file mode 100644
index 0000000..ed7be1e
--- /dev/null
+++ b/test/core/task_implicit_dir.v
@@ -0,0 +1,21 @@
+module top;
+    task t(
+        input reg [31:0] inp,
+        output reg [7:0] out1,
+        output reg [15:0] out2
+    );
+        begin
+            $display("t(inp = %0d)", inp);
+            out1 = inp;
+            out2 = inp;
+        end
+    endtask
+    initial begin : blk
+        reg [31:0] a;
+        reg [7:0] b;
+        reg [15:0] c;
+        a = 5;
+        t(a, b, c);
+        $display("a = %0d, b = %0d, c = %0d", a, b, c);
+    end
+endmodule