Re: [PATCH 12/12] efi: make const array 'apple' static
From: Ard Biesheuvel
Date: Fri Mar 09 2018 - 03:07:18 EST
On 9 March 2018 at 08:04, Ingo Molnar <mingo@xxxxxxxxxx> wrote:
>
> * Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> wrote:
>
>> > Also, would it make sense to rename it to something more descriptive like
>> > "apple_unicode_str[]" or so?
>> >
>> > Plus an unicode string literal initializer would be pretty descriptive as well,
>> > instead of the weird looking character array, i.e. something like:
>> >
>> > static efi_char16_t const apple_unicode_str[] = u"Apple";
>> >
>> > ... or so?
>> >
>>
>> is u"xxx" the same as L"xxx"?
>
> So "L" literals map to wchar_t, which wide character type is implementation
> specific IIRC, could be 16-bit or 32-bit wide.
>
> u"" literals OTOH are specified by the C11 spec to be char16_t, i.e. 16-bit wide
> characters - which I assume is the EFI type as well?
>
>> In any case, this is for historical reasons: at some point (and I
>> don't remember the exact details) we had a conflict at link time with
>> objects using 4 byte wchar_t, so we started using this notation to be
>> independent of the size of wchar_t. That issue no longer exists so we
>> should be able to get rid of this.
>
> Yes, my guess is that those problems were due to L"xyz" mapping to wchar_t and
> having a different type in the kernel build and the host build side - but u"xyz"
> should solve that.
>
Excellent!
Do you mind taking this patch as is? I will follow up with a patch
that updates all occurrences of this pattern (we have a few of them),
i.e., use u"" notation and move them to file scope.