Re: [PATCH v2] target/mips: Rewrite UHI errno_mips() using switch statement

[Thomas Huth <thuth@redhat.com>]

On 06/07/2021 15.07, Philippe Mathieu-Daudé wrote:
> Linking on Haiku OS fails:
> 
>    /boot/system/develop/tools/bin/../lib/gcc/x86_64-unknown-haiku/8.3.0/../../../../x86_64-unknown-haiku/bin/ld:
>    error: libqemu-mips-softmmu.fa.p/target_mips_tcg_sysemu_mips-semi.c.o(.rodata) is too large (0xffff405a bytes)
>    /boot/system/develop/tools/bin/../lib/gcc/x86_64-unknown-haiku/8.3.0/../../../../x86_64-unknown-haiku/bin/ld:
>    final link failed: memory exhausted
>    collect2: error: ld returned 1 exit status
> 
> This is because the host_to_mips_errno[] uses errno as index,
> for example:
> 
>    static const uint16_t host_to_mips_errno[] = {
>        [ENAMETOOLONG] = 91,
>        ...
> 
> and Haiku defines [*] ENAMETOOLONG as:
> 
>     12 /* Error baselines */
>     13 #define B_GENERAL_ERROR_BASE              INT_MIN
>     ..
>     22 #define B_STORAGE_ERROR_BASE              (B_GENERAL_ERROR_BASE + 0x6000)
>    ...
>    106 #define B_NAME_TOO_LONG                   (B_STORAGE_ERROR_BASE + 4)
>    ...
>    211 #define ENAMETOOLONG                      B_TO_POSIX_ERROR(B_NAME_TOO_LONG)
> 
> so the array ends up beeing indeed too big.
> 
> Since POSIX errno can't be use as indexes on Haiku,
> rewrite errno_mips() using a switch statement.
> 
> [*] https://github.com/haiku/haiku/blob/r1beta3/headers/os/support/Errors.h#L130
> 
> Reported-by: Richard Zak <richard.j.zak@gmail.com>
> Suggested-by: Thomas Huth <thuth@redhat.com>
> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> ---
> Supersedes: <20210704170736.617895-4-f4bug@amsat.org>
> ---
>   target/mips/tcg/sysemu/mips-semi.c | 24 +++++++++---------------
>   1 file changed, 9 insertions(+), 15 deletions(-)
> 
> diff --git a/target/mips/tcg/sysemu/mips-semi.c b/target/mips/tcg/sysemu/mips-semi.c
> index 77108b0b1a9..b4a383ae90c 100644
> --- a/target/mips/tcg/sysemu/mips-semi.c
> +++ b/target/mips/tcg/sysemu/mips-semi.c
> @@ -74,25 +74,19 @@ enum UHIOpenFlags {
>       UHIOpen_EXCL   = 0x800
>   };
>   
> -/* Errno values taken from asm-mips/errno.h */
> -static const uint16_t host_to_mips_errno[] = {
> -    [ENAMETOOLONG] = 78,
> +static int errno_mips(int host_errno)
> +{
> +    /* Errno values taken from asm-mips/errno.h */
> +    switch (host_errno) {
> +    case 0:             return 0;
> +    case ENAMETOOLONG:  return 78;
>   #ifdef EOVERFLOW
> -    [EOVERFLOW]    = 79,
> +    case EOVERFLOW:     return 79;
>   #endif
>   #ifdef ELOOP
> -    [ELOOP]        = 90,
> +    case ELOOP:         return 90;
>   #endif
> -};
> -
> -static int errno_mips(int err)
> -{
> -    if (err < 0 || err >= ARRAY_SIZE(host_to_mips_errno)) {
> -        return EINVAL;
> -    } else if (host_to_mips_errno[err]) {
> -        return host_to_mips_errno[err];
> -    } else {
> -        return err;
> +    default:            return EINVAL;
>       }
>   }

Reviewed-by: Thomas Huth <thuth@redhat.com>

I assume you'll do the number fixup (your previous "target/mips: Fix UHI 
error values" patch) on top of this now?