Re: [PATCH] parse: Fix sign extension in casting enums

[Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>]

On Tue, Sep 24, 2019 at 12:09 AM Dan Carpenter <dan.carpenter@xxxxxxxxxx> wrote:
>
> The problem is the sign isn't extended properly when this casts an int
> to a long.  The expr->ctype has to be the original int ctype for the
> cast_value() call so that the "value = get_longlong(old);" expansion
> works correctly.

What happens if you just remove the

        if (ctype->bit_size == base_type->bit_size) {
                expr->ctype = base_type;
                continue;
        }

part entirely? IOW, leave just

        cast_value(expr, base_type, expr, ctype);
        expr->ctype = base_type;

in place unconditionally? I _think- that should be the simpler correct
fix, but I'll leave it to Luc to think about it more.

That simpler alternate patch attached,

              Linus

 parse.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/parse.c b/parse.c
index f291e247..b01c876e 100644
--- a/parse.c
+++ b/parse.c
@@ -897,10 +897,8 @@ static void cast_enum_list(struct symbol_list *list, struct symbol *base_type)
 			expr->ctype = &int_ctype;
 			continue;
 		}
-		expr->ctype = base_type;
-		if (ctype->bit_size == base_type->bit_size)
-			continue;
 		cast_value(expr, base_type, expr, ctype);
+		expr->ctype = base_type;
 	} END_FOR_EACH_PTR(sym);
 }