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glibc/math/w_fmod_compat.c
Joseph Myers 813378e9fe Obsolete matherr, _LIB_VERSION, libieee.a. 
This patch obsoletes support for SVID libm error handling (the system
where a user-defined function matherr is called on a libm function
error; only enabled if you also set _LIB_VERSION = _SVID_ or
_LIB_VERSION = _XOPEN_) and the use of the _LIB_VERSION global
variable to control libm error handling.  matherr and _LIB_VERSION are
made into compat symbols, not supported for new ports or for static
linking.  The libieee.a object file (which sets _LIB_VERSION = _IEEE_,
so disabling errno setting for some functions) is also removed, and
all the related definitions are removed from math.h.

The manual already recommends against using matherr, and it's already
not supported for _Float128 functions (those use new wrappers that
don't support matherr, only errno) - this patch means that it becomes
possible to e.g. add sinf32 as an alias to sinf without that resulting
in undesired matherr support in sinf32 for existing glibc ports.
matherr support is not part of any standard supported by glibc (it was
removed in XPG4).

Because matherr is a function to be defined by the user, of course
user programs defining such a function will still continue to link; it
just quietly won't be used.  If they try to write to the library's
copy of _LIB_VERSION to enable SVID error handling, however, they will
get a link error (but if they define their own _LIB_VERSION variable,
they won't).

I expect the most likely case of build failures from this patch to be
programs with unconditional cargo-culted uses of -lieee (based on a
notion of "I want IEEE floating point", not any actual requirement for
that library).

Ideally, the new-port-or-static-linking case would use the new
wrappers used for _Float128.  This is not implemented in this patch,
because of the complication of architecture-specific (powerpc32 and
sparc) sqrt wrappers that use _LIB_VERSION and __kernel_standard
directly.  Thus, the old wrappers and __kernel_standard are still
built unconditionally, and _LIB_VERSION still exists in static libm.
But when the old wrappers and __kernel_standard are built in the
non-compat case, _LIB_VERSION and matherr are defined as macros so
code to support those features isn't actually built into static libm
or new ports' shared libm after this patch.

I intend to move to the new wrappers for static libm and new ports in
followup patches.  I believe the sqrt wrappers for powerpc32 and sparc
can reasonably be removed.  GCC already optimizes the normal case of
sqrt by generating code that uses a hardware instruction and only
calls the sqrt function if the argument was negative (if
-fno-math-errno, of course, it just uses the hardware instruction
without any check for negative argument being needed).  Thus those
wrappers will only actually get called in the case of negative
arguments, which is not a case it makes sense to optimize for.  But
even without removing the powerpc32 and sparc wrappers it should still
be possible to move to the new wrappers for static libm and new ports,
just without having those dubious architecture-specific optimizations
in static libm.

Everything said about matherr equally applies to matherrf and matherrl
(IA64-specific, undocumented), except that the structure of IA64 libm
means it won't be converted to using the new wrappers (it doesn't use
the old ones either, but its own error-handling code instead).

As with other tests of compat symbols, I expect test-matherr and
test-matherr-2 to need to become appropriately conditional once we
have a system for disabling such tests for ports too new to have the
relevant symbols.

Tested for x86_64 and x86, and with build-many-glibcs.py.

	* math/math.h [__USE_MISC] (_LIB_VERSION_TYPE): Remove.
	[__USE_MISC] (_LIB_VERSION): Likewise.
	[__USE_MISC] (struct exception): Likewise.
	[__USE_MISC] (matherr): Likewise.
	[__USE_MISC] (DOMAIN): Likewise.
	[__USE_MISC] (SING): Likewise.
	[__USE_MISC] (OVERFLOW): Likewise.
	[__USE_MISC] (UNDERFLOW): Likewise.
	[__USE_MISC] (TLOSS): Likewise.
	[__USE_MISC] (PLOSS): Likewise.
	[__USE_MISC] (HUGE): Likewise.
	[__USE_XOPEN] (MAXFLOAT): Define even if [__USE_MISC].
	* math/math-svid-compat.h: New file.
	* conform/linknamespace.pl (@whitelist): Remove matherr, matherrf
	and matherrl.
	* include/math.h [!_ISOMAC] (__matherr): Remove.
	* manual/arith.texi (FP Exceptions): Do not document matherr.
	* math/Makefile (tests): Change test-matherr to test-matherr-3.
	(tests-internal): New variable.
	(install-lib): Do not add libieee.a.
	(non-lib.a): Likewise.
	(extra-objs): Do not add libieee.a and ieee-math.o.
	(CPPFLAGS-s_lib_version.c): Remove variable.
	($(objpfx)libieee.a): Remove rule.
	($(addprefix $(objpfx), $(tests-internal)): Depend on $(libm).
	* math/ieee-math.c: Remove.
	* math/libm-test-support.c (matherr): Remove.
	* math/test-matherr.c: Use <support/test-driver.c>.  Add copyright
	and license notices.  Include <math-svid-compat.h> and
	<shlib-compat.h>.
	(matherr): Undefine as macro.  Use compat_symbol_reference.
	(_LIB_VERSION): Likewise.
	* math/test-matherr-2.c: New file.
	* math/test-matherr-3.c: Likewise.
	* sysdeps/generic/math_private.h (__kernel_standard): Remove
	declaration.
	(__kernel_standard_f): Likewise.
	(__kernel_standard_l): Likewise.
	* sysdeps/ieee754/s_lib_version.c: Do not include <math.h> or
	<math_private.h>.  Include <math-svid-compat.h>.
	(_LIB_VERSION): Undefine as macro.
	(_LIB_VERSION_INTERNAL): Always initialize to _POSIX_.  Define
	only if [LIBM_SVID_COMPAT || !defined SHARED].  If
	[LIBM_SVID_COMPAT], use compat_symbol.
	* sysdeps/ieee754/s_matherr.c: Do not include <math.h> or
	<math_private.h>.  Include <math-svid-compat.h>.
	(matherr): Undefine as macro.
	(__matherr): Define only if [LIBM_SVID_COMPAT].  Use
	compat_symbol.
	* sysdeps/ia64/fpu/libm_error.c: Include <math-svid-compat.h>.
	[_LIBC && LIBM_SVID_COMPAT] (matherrf): Use
	compat_symbol_reference.
	[_LIBC && LIBM_SVID_COMPAT] (matherrl): Likewise.
	[_LIBC && !LIBM_SVID_COMPAT] (matherrf): Define as macro.
	[_LIBC && !LIBM_SVID_COMPAT] (matherrl): Likewise.
	* sysdeps/ia64/fpu/libm_support.h: Include <math-svid-compat.h>.
	(MATHERR_D): Remove declaration.
	[!_LIBC] (_LIB_VERSION_TYPE): Likewise
	[!LIBM_BUILD] (_LIB_VERSIONIMF): Likewise.
	[LIBM_BUILD] (pmatherrf): Likewise.
	[LIBM_BUILD] (pmatherr): Likewise.
	[LIBM_BUILD] (pmatherrl): Likewise.
	(DOMAIN): Likewise.
	(SING): Likewise.
	(OVERFLOW): Likewise.
	(UNDERFLOW): Likewise.
	(TLOSS): Likewise.
	(PLOSS): Likewise.
	* sysdeps/ia64/fpu/s_matherrf.c: Include <math-svid-compat.h>.
	(__matherrf): Define only if [LIBM_SVID_COMPAT].  Use
	compat_symbol.
	* sysdeps/ia64/fpu/s_matherrl.c: Include <math-svid-compat.h>.
	(__matherrl): Define only if [LIBM_SVID_COMPAT].  Use
	compat_symbol.
	* math/lgamma-compat.h: Include <math-svid-compat.h>.
	* math/w_acos_compat.c: Likewise.
	* math/w_acosf_compat.c: Likewise.
	* math/w_acosh_compat.c: Likewise.
	* math/w_acoshf_compat.c: Likewise.
	* math/w_acoshl_compat.c: Likewise.
	* math/w_acosl_compat.c: Likewise.
	* math/w_asin_compat.c: Likewise.
	* math/w_asinf_compat.c: Likewise.
	* math/w_asinl_compat.c: Likewise.
	* math/w_atan2_compat.c: Likewise.
	* math/w_atan2f_compat.c: Likewise.
	* math/w_atan2l_compat.c: Likewise.
	* math/w_atanh_compat.c: Likewise.
	* math/w_atanhf_compat.c: Likewise.
	* math/w_atanhl_compat.c: Likewise.
	* math/w_cosh_compat.c: Likewise.
	* math/w_coshf_compat.c: Likewise.
	* math/w_coshl_compat.c: Likewise.
	* math/w_exp10_compat.c: Likewise.
	* math/w_exp10f_compat.c: Likewise.
	* math/w_exp10l_compat.c: Likewise.
	* math/w_exp2_compat.c: Likewise.
	* math/w_exp2f_compat.c: Likewise.
	* math/w_exp2l_compat.c: Likewise.
	* math/w_fmod_compat.c: Likewise.
	* math/w_fmodf_compat.c: Likewise.
	* math/w_fmodl_compat.c: Likewise.
	* math/w_hypot_compat.c: Likewise.
	* math/w_hypotf_compat.c: Likewise.
	* math/w_hypotl_compat.c: Likewise.
	* math/w_j0_compat.c: Likewise.
	* math/w_j0f_compat.c: Likewise.
	* math/w_j0l_compat.c: Likewise.
	* math/w_j1_compat.c: Likewise.
	* math/w_j1f_compat.c: Likewise.
	* math/w_j1l_compat.c: Likewise.
	* math/w_jn_compat.c: Likewise.
	* math/w_jnf_compat.c: Likewise.
	* math/w_jnl_compat.c: Likewise.
	* math/w_lgamma_main.c: Likewise.
	* math/w_lgamma_r_compat.c: Likewise.
	* math/w_lgammaf_main.c: Likewise.
	* math/w_lgammaf_r_compat.c: Likewise.
	* math/w_lgammal_main.c: Likewise.
	* math/w_lgammal_r_compat.c: Likewise.
	* math/w_log10_compat.c: Likewise.
	* math/w_log10f_compat.c: Likewise.
	* math/w_log10l_compat.c: Likewise.
	* math/w_log2_compat.c: Likewise.
	* math/w_log2f_compat.c: Likewise.
	* math/w_log2l_compat.c: Likewise.
	* math/w_log_compat.c: Likewise.
	* math/w_logf_compat.c: Likewise.
	* math/w_logl_compat.c: Likewise.
	* math/w_pow_compat.c: Likewise.
	* math/w_powf_compat.c: Likewise.
	* math/w_powl_compat.c: Likewise.
	* math/w_remainder_compat.c: Likewise.
	* math/w_remainderf_compat.c: Likewise.
	* math/w_remainderl_compat.c: Likewise.
	* math/w_scalb_compat.c: Likewise.
	* math/w_scalbf_compat.c: Likewise.
	* math/w_scalbl_compat.c: Likewise.
	* math/w_sinh_compat.c: Likewise.
	* math/w_sinhf_compat.c: Likewise.
	* math/w_sinhl_compat.c: Likewise.
	* math/w_sqrt_compat.c: Likewise.
	* math/w_sqrtf_compat.c: Likewise.
	* math/w_sqrtl_compat.c: Likewise.
	* math/w_tgamma_compat.c: Likewise.
	* math/w_tgammaf_compat.c: Likewise.
	* math/w_tgammal_compat.c: Likewise.
	* sysdeps/ieee754/dbl-64/w_exp_compat.c: Likewise.
	* sysdeps/ieee754/flt-32/w_expf_compat.c: Likewise.
	* sysdeps/ieee754/k_standard.c: Likewise.
	* sysdeps/ieee754/k_standardf.c: Likewise.
	* sysdeps/ieee754/k_standardl.c: Likewise.
	* sysdeps/ieee754/ldbl-128/w_expl_compat.c: Likewise.
	* sysdeps/ieee754/ldbl-128ibm/w_expl_compat.c: Likewise.
	* sysdeps/ieee754/ldbl-96/w_expl_compat.c: Likewise.
	* sysdeps/powerpc/powerpc32/power4/fpu/w_sqrt_compat.S: Likewise.
	* sysdeps/powerpc/powerpc32/power4/fpu/w_sqrtf_compat.S: Likewise.
	* sysdeps/powerpc/powerpc32/power5/fpu/w_sqrt_compat.S: Likewise.
	* sysdeps/powerpc/powerpc32/power5/fpu/w_sqrtf_compat.S: Likewise.
	* sysdeps/sparc/sparc32/fpu/w_sqrt_compat.S: Likewise.
	* sysdeps/sparc/sparc32/fpu/w_sqrtf_compat.S: Likewise.
	* sysdeps/sparc/sparc32/sparcv9/fpu/multiarch/w_sqrt_compat-vis3.S:
	Likewise.
	* sysdeps/sparc/sparc32/sparcv9/fpu/multiarch/w_sqrtf_compat-vis3.S:
	Likewise.
	* sysdeps/sparc/sparc32/sparcv9/fpu/w_sqrt_compat.S: Likewise.
	* sysdeps/sparc/sparc32/sparcv9/fpu/w_sqrtf_compat.S: Likewise.
	* sysdeps/sparc/sparc64/fpu/w_sqrt_compat.S: Likewise.
	* sysdeps/sparc/sparc64/fpu/w_sqrtf_compat.S: Likewise.
2017-08-21 17:45:10 +00:00

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/* Copyright (C) 2011-2017 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@gmail.com>, 2011.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <math.h>
#include <math_private.h>
#include <math-svid-compat.h>
/* wrapper fmod */
double
__fmod (double x, double y)
{
if (__builtin_expect (isinf (x) || y == 0.0, 0)
&& _LIB_VERSION != _IEEE_ && !isnan (y) && !isnan (x))
/* fmod(+-Inf,y) or fmod(x,0) */
return __kernel_standard (x, y, 27);
return __ieee754_fmod (x, y);
}
weak_alias (__fmod, fmod)
#ifdef NO_LONG_DOUBLE
strong_alias (__fmod, __fmodl)
weak_alias (__fmod, fmodl)
#endif
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