handle size casts of string parameters

src/Convert/TypeOf.hs

@@ -131,9 +131,21 @@ traverseExprM other =
 elaborateSizeCast :: Expr -> Expr -> ST Expr
 elaborateSizeCast size value = do
     t <- typeof value
-    case typeSignedness t of
-        Unspecified -> return $ Cast (Right size) value
-        sg -> traverseExprM $ Cast (Left $ typeOfSize sg size) value
+    force <- isStringParam value
+    case (typeSignedness t, force) of
+        (Unspecified, False)-> return $ Cast (Right size) value
+        (sg, _) -> traverseExprM $ Cast (Left $ typeOfSize sg size) value
+
+-- string params use a self-referential type to enable the string param
+-- conversion to add a synthetic parameter if necessary; this check enables size
+-- casts to assume a string parameter is unsigned regardless of its length
+isStringParam :: Expr -> ST Bool
+isStringParam (Ident x) = do
+    details <- lookupElemM x
+    return $ case details of
+        Nothing -> False
+        Just (_, _, typ) -> typ == TypeOf (Ident x)
+isStringParam _ = return False
 
 -- convert TypeOf in a Type
 traverseTypeM :: Type -> ST Type

test/core/string_cast.sv

+`ifdef REF
+    `define TEST(size) \
+        begin : blk``size \
+            reg [size - 1:0] trim; \
+            trim = P; $display(`"size'(P) = %b`", trim); \
+            trim = L; $display(`"size'(L) = %b`", trim); \
+        end
+`else
+    `define TEST(size) \
+        $display(`"size'(P) = %b`", size'(P)); \
+        $display(`"size'(L) = %b`", size'(L));
+`endif
+module mod;
+    parameter P = "asdf";
+    localparam L = "foobar";
+    initial begin
+        `TEST(1) `TEST(2) `TEST(3) `TEST(4) `TEST(5)
+        `TEST(6) `TEST(7) `TEST(8) `TEST(9) `TEST(10)
+        `TEST(11) `TEST(12) `TEST(13) `TEST(14) `TEST(15)
+        `TEST(16) `TEST(17) `TEST(18) `TEST(19) `TEST(20)
+        `TEST(21) `TEST(22) `TEST(23) `TEST(24) `TEST(25)
+        `TEST(26) `TEST(27) `TEST(28) `TEST(29) `TEST(30)
+        `TEST(31) `TEST(32) `TEST(33) `TEST(34) `TEST(35)
+        `TEST(36) `TEST(37) `TEST(38) `TEST(39) `TEST(40)
+        `TEST(41) `TEST(42) `TEST(43) `TEST(44) `TEST(45)
+        `TEST(46) `TEST(47) `TEST(48) `TEST(49) `TEST(50)
+        `TEST(51) `TEST(52) `TEST(53) `TEST(54) `TEST(55)
+    end
+endmodule

test/core/string_cast.v

+`define REF
+`include "string_cast.sv"

test/core/string_cast_tb.v

+module top;
+    mod m1();
+    mod #("foo") m2();
+    mod #("bar") m3();
+    mod #("foobar") m4();
+endmodule

test/core/typeof_signed.sv

@@ -199,4 +199,11 @@ module top;
     `ASSERT_UNSIGNED(integer_signed[1])
     `ASSERT_UNSIGNED(integer_unsigned[0])
     `ASSERT_UNSIGNED(integer_unsigned[1])
+
+    parameter STR_P = "foo";
+    localparam STR_L = "foo";
+    `ASSERT_UNSIGNED(STR_P)
+    `ASSERT_UNSIGNED(STR_L)
+    `ASSERT_UNSIGNED(64'(STR_P))
+    `ASSERT_UNSIGNED(64'(STR_L))
 endmodule