Re: [PATCH v3 26/60] target/arm: Replace sentinels with ARRAY_SIZE in cpregs.h

[Peter Maydell]

On Sun, 17 Apr 2022 at 19:08, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> Remove a possible source of error by removing REGINFO_SENTINEL
> and using ARRAY_SIZE (convinently hidden inside a macro) to
> find the end of the set of regs being registered or modified.
>
> The space saved by not having the extra array element reduces
> the executable's .data.rel.ro section by about 9k.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---




> +#define define_arm_cp_regs_with_opaque(CPU, REGS, OPAQUE)               \
> +    do {                                                                \
> +        QEMU_BUILD_BUG_ON(ARRAY_SIZE(REGS) == 0);                       \
> +        if (ARRAY_SIZE(REGS) == 1) {                                    \
> +            define_one_arm_cp_reg_with_opaque(CPU, REGS, OPAQUE);       \
> +        } else {                                                        \
> +            define_arm_cp_regs_with_opaque_len(CPU, REGS, OPAQUE,       \
> +                                               ARRAY_SIZE(REGS));       \
> +        }                                                               \
> +    } while (0)

Do we actually need to special case "array has one element" here,
or is this just efficiency?

Anyway
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

thanks
-- PMM