[PATCH] Make out of range type conversions explicit

[Luis Machado]

If the approach is acceptable, we should at least make it clear, through 
comments, that this is being done for clang. Having these casts in the 
code, without an explanation, is a bit cryptic.

On 6/30/20 10:58 AM, Gary Benson via Gdb-patches wrote:
> HI all,
> 
> Clang fails to compile two testcases with the following warning:
> implicit conversion from 'X' to 'Y' changes value from x to y
> [-Wconstant-conversion].  This patch adds casts that make the
> value-changing conversions explicit.
> 
> Checked on Fedora 31 x86_64, GCC and clang.  Ok to commit?
> 
> Cheers,
> Gary
> 
> --
> gdb/testsuite/ChangeLog:
> 
> 	* gdb.base/charset.c (main): Explicitly cast values which are
> 	out of range of their destination types.
> 	* gdb.base/structs2.c (main): Likewise.
> ---
>   gdb/testsuite/ChangeLog           | 6 ++++++
>   gdb/testsuite/gdb.base/charset.c  | 6 +++---
>   gdb/testsuite/gdb.base/structs2.c | 2 +-
>   3 files changed, 10 insertions(+), 4 deletions(-)
> 
> diff --git a/gdb/testsuite/gdb.base/charset.c b/gdb/testsuite/gdb.base/charset.c
> index ec4927d..54bd2dd 100644
> --- a/gdb/testsuite/gdb.base/charset.c
> +++ b/gdb/testsuite/gdb.base/charset.c
> @@ -141,14 +141,14 @@ int main ()
>                  120,
>                  7, 8, 12,
>                  10, 13, 9,
> -               11, 162, 17);
> +               11, (char) 162, 17);
>     fill_run (iso_8859_1_string, 7, 26, 65);
>     fill_run (iso_8859_1_string, 33, 26, 97);
>     fill_run (iso_8859_1_string, 59, 10, 48);
>   
>     /* Initialize ebcdic_us_string.  */
>     init_string (ebcdic_us_string,
> -               167,
> +               (char) 167,
>                  47, 22, 12,
>                  37, 13, 5,
>                  11, 74, 17);
> @@ -165,7 +165,7 @@ int main ()
>   
>     /* Initialize ibm1047_string.  */
>     init_string (ibm1047_string,
> -               167,
> +               (char) 167,
>                  47, 22, 12,
>                  37, 13, 5,
>                  11, 74, 17);
> diff --git a/gdb/testsuite/gdb.base/structs2.c b/gdb/testsuite/gdb.base/structs2.c
> index 7c8be03..2847cd6 100644
> --- a/gdb/testsuite/gdb.base/structs2.c
> +++ b/gdb/testsuite/gdb.base/structs2.c
> @@ -13,7 +13,7 @@ static void param_reg (register signed char pr_char,
>   
>     bkpt = 0;
>     param_reg (120, 130, 32000, 33000);
> -  param_reg (130, 120, 33000, 32000);
> +  param_reg ((signed char) 130, 120, (short) 33000, 32000);
>   
>     return 0;
>   }
>