Re: [PATCH v2 8/8] linux-user: Simplify host <-> target errno conversion using macros

[Laurent Vivier]

Le 08/07/2021 à 16:11, Philippe Mathieu-Daudé a écrit :
> Convert the host_to_target_errno_table[] array to a switch case
> to allow compiler optimizations. Extract the errnos list as to
> a new includible unit, using a generic macro. Remove the code
> related to target_to_host_errno_table[] initialization.
> 

Is there some performance penalties by using a switch() rather than an array[] ?

> Suggested-by: Richard Henderson <richard.henderson@linaro.org>
> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> ---
>  linux-user/syscall.c    | 169 +++++-----------------------------------
>  linux-user/errnos.c.inc | 140 +++++++++++++++++++++++++++++++++
>  2 files changed, 161 insertions(+), 148 deletions(-)
>  create mode 100644 linux-user/errnos.c.inc
> 
...
> diff --git a/linux-user/errnos.c.inc b/linux-user/errnos.c.inc
> new file mode 100644
> index 00000000000..807c97ca25e
> --- /dev/null
> +++ b/linux-user/errnos.c.inc
> @@ -0,0 +1,140 @@
...
> +#ifdef ERKFILL

You fix it in patch 1 but forgot to report it in your patch :)

Thanks,
Laurent