Re: [PATCH v3 2/5] powerpc: Add redirection for finitef128, isinf128, and isnanf128

["Tulio Magno Quites Machado Filho" <tuliom@linux.vnet.ibm.com>]

"Gabriel F. T. Gomes" <gabriel@inconstante.eti.br> writes:

> On 19 Sep 2017, Tulio Magno Quites Machado Filho wrote:
>
>>"Gabriel F. T. Gomes" <gabriel@inconstante.eti.br> writes:
>>
>>> The errors are due to the unintended macro expansion of __finitef128 to
>>> __redirect_finitef128 in math/bits/mathcalls-helper-functions.h.  In  
>>
>>AFAIU, the expansion of __finitef128 to __redirect_finitef128 in
>>math/bits/mathcalls-helper-functions.h is expected.  The problem happens when
>>the same thing doesn't happen in include/math.h too.
>
> I mean unintended in the sense that the expansion of __finitef and
> __finitel, which pertain to float and long double, are happening in
> s_finite.c, which is the *double* implementation of finite.  Compare that
> with s_finitef.c, which only redefines __finitef, leaving the other macros
> (__finite and __finitel) untouched.

Got it!

> On the other hand, I agree that my comments did not fully explain the
> problem.  They only mention the expansion in mathcalls-helper-functions.h
> and do not say anything about the hidden prototypes in include/math.h.
>
> So, how about expanding this paragraph to:
>
>   The errors are due to the unintended macro expansion of __finitef128 to
>   __redirect_finitef128 in math/bits/mathcalls-helper-functions.h.  In
>   that header, __MATHDECL_1 takes '__finite' and 'f128' as arguments and
>   concatenates them.  However, since '__finite' has been redefined in
>   s_finite.c, the function declaration becomes __redirect_finitef128:
>
>     extern int __redirect___finitef128 (_Float128 __value) __attribute__ ((__nothrow__ )) __attribute__ ((__const__));
>
>   This declaration itself is OK.  The problem arises when include/math.h
>   creates the hidden prototype ('hidden_proto (__finitef128)'), which
>   expands to:
>
>     extern __typeof (__finitef128) __finitef128 __attribute__ ((visibility ("hidden")));
>
>   Since __finitef128 is not declared, __typeof fails.  This effect was
>   already true for the 'float' and 'long double' versions and is now true
>   for float128.  Likewise for isinsff128 and isnanf128.

Looks good to me.

>>> +/* The following definitions, although not related to the 'double'
>>> +   version of 'finite', are required to compensate for the unintended
>>> +   macro expansion of __finitef to __redirect___finitef, etc. in
>>> +   math/bits/mathcalls-helper-functions.h.  */  
>>
>>Likewise.
>>I suggest the following change:
>>
>>/* The following definitions, although not related to the 'double'
>>   version of 'finite', are required to guarantee the macro expansion
>>   of __finitef to __redirect___finitef, etc. in
>>   math/bits/mathcalls-helper-functions.h and include/math.h.  */
>
> The expansion in mathcalls-helper-functions.h is unintended, but we need
> to guarantee the same expansion in include/math.h, so what about the
> following:
>
>   The following definitions, although not related to the 'double' version
>   of 'finite', are required to guarantee expansions (e.g.: from __finitef
>   to __redirect_finitef) in include/math.h, thus compensating for the
>   unintended macro expansions in math/bits/mathcalls-helper-functions.h.
>
> OK with these changes?

Yes, assuming you also include the #undef lines I mentioned in my previous
email.

Thanks!

-- 
Tulio Magno