Re: [PATCH] linux-user: fix implicit conversion from enumeration type error

[Philippe Mathieu-Daudé]

On 9/1/20 5:33 PM, Laurent Vivier wrote:
> MK_ARRAY(type,size) is used to fill the field_types buffer, and if the
> "size" parameter is an enum type, clang [-Werror,-Wenum-conversion] reports
> an error when it is assigned to field_types which is also an enum, argtypes.
> 
> To avoid that, convert "size" to "int" in MK_ARRAY(). "int" is the type
> used for the size evaluation in thunk_type_size().
> 
> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
> ---
>  include/exec/user/thunk.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/include/exec/user/thunk.h b/include/exec/user/thunk.h
> index a5bbb2c73331..b798fcb69cf4 100644
> --- a/include/exec/user/thunk.h
> +++ b/include/exec/user/thunk.h
> @@ -42,7 +42,7 @@ typedef enum argtype {
>  } argtype;
>  
>  #define MK_PTR(type) TYPE_PTR, type
> -#define MK_ARRAY(type, size) TYPE_ARRAY, size, type
> +#define MK_ARRAY(type, size) TYPE_ARRAY, (int)size, type

You need to use parenthesis:

  #define MK_ARRAY(type, size) TYPE_ARRAY, (int)(size), type

See:

  MK_ARRAY(TYPE_CHAR, USBDEVFS_MAXDRIVERNAME + 1)) /* driver */

While here I'd also add them to 'type'.

With parenthesis:
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

>  #define MK_STRUCT(id) TYPE_STRUCT, id
>  
>  #define THUNK_TARGET 0
>