RE: [PATCH 06/10] fortify: replace __is_constexpr() by is_const() in strlen()

[David Laight <David.Laight@ACULAB.COM>]

From: Vincent Mailhol
> Sent: 02 December 2024 17:33
> 
> From: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
> 
> is_const() is a one to one replacement of __is_constexpr(). Do the
> replacement so that __is_constexpr() can be removed.
> 
> Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
> ---
>  include/linux/fortify-string.h | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/include/linux/fortify-string.h b/include/linux/fortify-string.h
> index 0d99bf11d260a3482bbe46e35c7553c0ccfb8b94..e3f2f772c5439ef71eb4a904b4ce27956bc69743 100644
> --- a/include/linux/fortify-string.h
> +++ b/include/linux/fortify-string.h
> @@ -254,8 +254,8 @@ __FORTIFY_INLINE __kernel_size_t strnlen(const char * const POS p, __kernel_size
>   * Returns number of characters in @p (NOT including the final NUL).
>   *
>   */
> -#define strlen(p)							\
> -	__builtin_choose_expr(__is_constexpr(__builtin_strlen(p)),	\
> +#define strlen(p)						\
> +	__builtin_choose_expr(is_const(__builtin_strlen(p)),	\
>  		__builtin_strlen(p), __fortify_strlen(p))

I'm sure Linus suggested a way of doing that without replicating
the __builtin_strlen().

Indeed it may be valid to do:
	len = __builtin_strlen(p);
	__builtin_constant_p(len) ? len : __fortify_strlen(p);

	David

>  __FORTIFY_INLINE __diagnose_as(__builtin_strlen, 1)
>  __kernel_size_t __fortify_strlen(const char * const POS p)
> 
> --
> 2.45.2
> 
> 

-
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