Re: [edk2-devel] [PATCH] MdePkg: DebugLib: Compilation fix for clang-13.

["Michael Brown" <mcb30@ipxe.org>]

On 23/11/2021 06:41, Marvin Häuser wrote:
> 23.11.2021 00:17:30 Michael Brown <mcb30@ipxe.org>:
>> I would very strongly recommend having the non-debug version of the macro use something like:
>>
>> #define ASSERT(Expression) do {   \
>>       if (FALSE) {                  \
>>         (VOID) (Expression);        \
>>       }                             \
>>     } while (FALSE)
>>
>> Without the "if (FALSE)", you will find that an expression that may have side-effects (e.g. by calling an external function) will result in executable code being generated.
> 
> In theory +1, but don't some compilers generate "unreachable code" warnings for this? I unfortunately cannot check them all right now. Maybe guards push/pop'ing the warning for that need to be defined, that are only allowed to be used with explicit documentation why they are necessary?

A quick experiment shows that gcc won't generate a warning but clang 
will.  Can be fixed by adding extra parentheses around FALSE:

#define ASSERT(Expression) do {   \
     if ((FALSE)) {                \
       (VOID) (Expression);        \
     }                             \
   } while (FALSE)

which is still clean and relatively elegant.

Thanks,

Michael