Re: Enum size checks in Base.h (UINT32 not ISO C compatible)

["Rebecca Cran" <rebecca@bsdio.com>]

I've sent a patch (https://edk2.groups.io/g/devel/message/99903).

On 2/8/23 19:28, Kinney, Michael D wrote:
> Hi Rebecca,
> 
> Great catch!!!  I think the static assert verifier is incorrect.
> 
> The UEFI Spec does clearly state in Section 2.3.1 that enum values
> can be type INT32 or UINT32.  The use of 0xFFFFFFFF assumes use of
> only UINT32.  I agree that the correct value to assign to the 32-bit
> enum value for this size check should be 0x7FFFFFFFF.
> 
> Mike
> 
>> -----Original Message-----
>> From: Rebecca Cran <rebecca@bsdio.com>
>> Sent: Wednesday, February 8, 2023 6:20 PM
>> To: devel@edk2.groups.io; Kinney, Michael D <michael.d.kinney@intel.com>; Gao, Liming <gaoliming@byosoft.com.cn>
>> Subject: Enum size checks in Base.h (UINT32 not ISO C compatible)
>>
>> In commit 6440385b17def888544c2454ffba58384b929a22
>> (https://github.com/tianocore/edk2/commit/6440385b17def888544c2454ffba58384b929a22)
>> enum size checks were added.
>>
>> However, according to gcc, ISO C restricts the size of enum values to
>> int; building with -std=c11 -pedantic results in the error:
>>
>> MdePkg/Include/Base.h:812:28: error: ISO C restricts enumerator values
>> to range of ‘int’ [-Werror=pedantic]
>>     812 |   __VerifyInt32EnumValue = 0xffffffff
>>
>> Replacing 0xffffffff with 0x7fffffff fixes the problem.
>>
>> It looks like this might change in C23, but since the use of
>> _Static_assert in Base.h we require at least C11 (and I suspect most
>> compilers aren't C23 compliant) which states:
>>
>> "The expression that defines the value of an enumeration constant shall
>> be an integer constant expression that has a value representable as an int.
>> [Section 6.7.2.2]"
>>
>> The UEFI Specification appears to say we require an INT32 (i.e. a signed
>> int) so is the existing code wrong?
>>
>> --
>> Rebecca Cran