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

No changes since v2.

Changes since v1:

  - Added comments to explain the need to redefine __finitef, __finitel,
    and __finitef128 in s_finite.c.  Likewise for isinf and isnan.

-- 8< --
On powerpc64le, compiler support for float128 is not enabled by default
on gcc.  To enable it, the flag -mfloat128 must be passed as a command
line option to the compiler.  This means that only the few files that
actively have -mfloat128 passed as an argument get compiler support for
float128, whereas all other files don't.

When -mfloat128 becomes enabled by default on powerpc [1], all the files
that do not currently have compiler support for float128 enabled during
their compilation, will start to have it.  This will lead to build
errors in s_finite.c, s_isinf.c, and s_isnan.c.

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, but '__finite' has been redefined in s_finite.c.
This effect was already true for the 'float' and 'long double' versions
and is now true for float128.  Likewise for isinsff128 and isnanf128.

This patch defines __finitef128 as __redirect___finitef128 in
sysdeps/powerpc/powerpc64/fpu/multiarch/s_finite.c, similarly to what's
done for the float and long double versions of these functions, to get
rid of the build error.  Likewise for isinff128 and isnanf128.

[1] https://gcc.gnu.org/ml/gcc-patches/2017-08/msg01028.html

Tested for powerpc64 and powerpc64le.

	* sysdeps/powerpc/powerpc64/fpu/multiarch/s_finite.c
	(__finitef128): Define to __redirect___finitef128.
	* sysdeps/powerpc/powerpc64/fpu/multiarch/s_isinf.c
	(__isinff128): Define to __redirect___isinff128.
	* sysdeps/powerpc/powerpc64/fpu/multiarch/s_isnan.c
	(__isnanf128): Define to __redirect___isnanf128.
---
 sysdeps/powerpc/powerpc64/fpu/multiarch/s_finite.c | 7 +++++++
 sysdeps/powerpc/powerpc64/fpu/multiarch/s_isinf.c  | 7 +++++++
 sysdeps/powerpc/powerpc64/fpu/multiarch/s_isnan.c  | 7 +++++++
 3 files changed, 21 insertions(+)

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

> On powerpc64le, compiler support for float128 is not enabled by default
> on gcc.  To enable it, the flag -mfloat128 must be passed as a command
> line option to the compiler.  This means that only the few files that
> actively have -mfloat128 passed as an argument get compiler support for
> float128, whereas all other files don't.
>
> When -mfloat128 becomes enabled by default on powerpc [1], all the files
> that do not currently have compiler support for float128 enabled during
> their compilation, will start to have it.  This will lead to build
> errors in s_finite.c, s_isinf.c, and s_isnan.c.
>
> 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.

In that case, I suggest to rewrite this part as:

The errors are due to the macro expansion of __finitef128 to
__redirect_finitef128 in math/bits/mathcalls-helper-functions.h without
expanding it in include/math.h too.

> diff --git a/sysdeps/powerpc/powerpc64/fpu/multiarch/s_finite.c b/sysdeps/powerpc/powerpc64/fpu/multiarch/s_finite.c
> index a5ec36b72f..0382bfb95c 100644
> --- a/sysdeps/powerpc/powerpc64/fpu/multiarch/s_finite.c
> +++ b/sysdeps/powerpc/powerpc64/fpu/multiarch/s_finite.c
> @@ -17,8 +17,15 @@
>     <http://www.gnu.org/licenses/>.  */
>
>  #define __finite __redirect___finite
> +
> +/* 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.  */

>  #define __finitef __redirect___finitef
>  #define __finitel __redirect___finitel
> +#define __finitef128 __redirect___finitef128
> +
>  #include <math.h>
>  #include <math_ldbl_opt.h>
>  #include <shlib-compat.h>

Don't you have to undefine this macro later in this file?

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.

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.

>> +/* 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?

"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!