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Author SHA1 Message Date
Joseph Myers
e44acb2063 Use floor functions not __floor functions in glibc libm. 
Similar to the changes that were made to call sqrt functions directly
in glibc, instead of __ieee754_sqrt variants, so that the compiler
could inline them automatically without needing special inline
definitions in lots of math_private.h headers, this patch makes libm
code call floor functions directly instead of __floor variants,
removing the inlines / macros for x86_64 (SSE4.1) and powerpc
(POWER5).

The redirection used to ensure that __ieee754_sqrt does still get
called when the compiler doesn't inline a built-in function expansion
is refactored so it can be applied to other functions; the refactoring
is arranged so it's not limited to unary functions either (it would be
reasonable to use this mechanism for copysign - removing the inline in
math_private_calls.h but also eliminating unnecessary local PLT entry
use in the cases (powerpc soft-float and e500v1, for IBM long double)
where copysign calls don't get inlined).

The point of this change is that more architectures can get floor
calls inlined where they weren't previously (AArch64, for example),
without needing special inline definitions in their math_private.h,
and existing such definitions in math_private.h headers can be
removed.

Note that it's possible that in some cases an inline may be used where
an IFUNC call was previously used - this is the case on x86_64, for
example.  I think the direct calls to floor are still appropriate; if
there's any significant performance cost from inline SSE2 floor
instead of an IFUNC call ending up with SSE4.1 floor, that indicates
that either the function should be doing something else that's faster
than using floor at all, or it should itself have IFUNC variants, or
that the compiler choice of inlining for generic tuning should change
to allow for the possibility that, by not inlining, an SSE4.1 IFUNC
might be called at runtime - but not that glibc should avoid calling
floor internally.  (After all, all the same considerations would apply
to any user program calling floor, where it might either be inlined or
left as an out-of-line call allowing for a possible IFUNC.)

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

	* include/math.h [!_ISOMAC && !(__FINITE_MATH_ONLY__ &&
	__FINITE_MATH_ONLY__ > 0) && !NO_MATH_REDIRECT] (MATH_REDIRECT):
	New macro.
	[!_ISOMAC && !(__FINITE_MATH_ONLY__ && __FINITE_MATH_ONLY__ > 0)
	&& !NO_MATH_REDIRECT] (MATH_REDIRECT_LDBL): Likewise.
	[!_ISOMAC && !(__FINITE_MATH_ONLY__ && __FINITE_MATH_ONLY__ > 0)
	&& !NO_MATH_REDIRECT] (MATH_REDIRECT_F128): Likewise.
	[!_ISOMAC && !(__FINITE_MATH_ONLY__ && __FINITE_MATH_ONLY__ > 0)
	&& !NO_MATH_REDIRECT] (MATH_REDIRECT_UNARY_ARGS): Likewise.
	[!_ISOMAC && !(__FINITE_MATH_ONLY__ && __FINITE_MATH_ONLY__ > 0)
	&& !NO_MATH_REDIRECT] (sqrt): Redirect using MATH_REDIRECT.
	[!_ISOMAC && !(__FINITE_MATH_ONLY__ && __FINITE_MATH_ONLY__ > 0)
	&& !NO_MATH_REDIRECT] (floor): Likewise.
	* sysdeps/aarch64/fpu/s_floor.c: Define NO_MATH_REDIRECT before
	header inclusion.
	* sysdeps/aarch64/fpu/s_floorf.c: Likewise.
	* sysdeps/ieee754/dbl-64/s_floor.c: Likewise.
	* sysdeps/ieee754/dbl-64/wordsize-64/s_floor.c: Likewise.
	* sysdeps/ieee754/float128/s_floorf128.c: Likewise.
	* sysdeps/ieee754/flt-32/s_floorf.c: Likewise.
	* sysdeps/ieee754/ldbl-128/s_floorl.c: Likewise.
	* sysdeps/ieee754/ldbl-128ibm/s_floorl.c: Likewise.
	* sysdeps/m68k/m680x0/fpu/s_floor_template.c: Likewise.
	* sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_floor.c: Likewise.
	* sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_floorf.c: Likewise.
	* sysdeps/powerpc/powerpc64/fpu/multiarch/s_floor.c: Likewise.
	* sysdeps/powerpc/powerpc64/fpu/multiarch/s_floorf.c: Likewise.
	* sysdeps/riscv/rv64/rvd/s_floor.c: Likewise.
	* sysdeps/riscv/rvf/s_floorf.c: Likewise.
	* sysdeps/sparc/sparc64/fpu/multiarch/s_floor.c: Likewise.
	* sysdeps/sparc/sparc64/fpu/multiarch/s_floorf.c: Likewise.
	* sysdeps/x86_64/fpu/multiarch/s_floor.c: Likewise.
	* sysdeps/x86_64/fpu/multiarch/s_floorf.c: Likewise.
	* sysdeps/powerpc/fpu/math_private.h [_ARCH_PWR5X] (__floor):
	Remove macro.
	[_ARCH_PWR5X] (__floorf): Likewise.
	* sysdeps/x86_64/fpu/math_private.h [__SSE4_1__] (__floor): Remove
	inline function.
	[__SSE4_1__] (__floorf): Likewise.
	* math/w_lgamma_main.c (LGFUNC (__lgamma)): Use floor functions
	instead of __floor variants.
	* math/w_lgamma_r_compat.c (__lgamma_r): Likewise.
	* math/w_lgammaf_main.c (LGFUNC (__lgammaf)): Likewise.
	* math/w_lgammaf_r_compat.c (__lgammaf_r): Likewise.
	* math/w_lgammal_main.c (LGFUNC (__lgammal)): Likewise.
	* math/w_lgammal_r_compat.c (__lgammal_r): Likewise.
	* math/w_tgamma_compat.c (__tgamma): Likewise.
	* math/w_tgamma_template.c (M_DECL_FUNC (__tgamma)): Likewise.
	* math/w_tgammaf_compat.c (__tgammaf): Likewise.
	* math/w_tgammal_compat.c (__tgammal): Likewise.
	* sysdeps/ieee754/dbl-64/e_lgamma_r.c (sin_pi): Likewise.
	* sysdeps/ieee754/dbl-64/k_rem_pio2.c (__kernel_rem_pio2):
	Likewise.
	* sysdeps/ieee754/dbl-64/lgamma_neg.c (__lgamma_neg): Likewise.
	* sysdeps/ieee754/flt-32/e_lgammaf_r.c (sin_pif): Likewise.
	* sysdeps/ieee754/flt-32/lgamma_negf.c (__lgamma_negf): Likewise.
	* sysdeps/ieee754/ldbl-128/e_lgammal_r.c (__ieee754_lgammal_r):
	Likewise.
	* sysdeps/ieee754/ldbl-128/e_powl.c (__ieee754_powl): Likewise.
	* sysdeps/ieee754/ldbl-128/lgamma_negl.c (__lgamma_negl):
	Likewise.
	* sysdeps/ieee754/ldbl-128/s_expm1l.c (__expm1l): Likewise.
	* sysdeps/ieee754/ldbl-128ibm/e_lgammal_r.c (__ieee754_lgammal_r):
	Likewise.
	* sysdeps/ieee754/ldbl-128ibm/e_powl.c (__ieee754_powl): Likewise.
	* sysdeps/ieee754/ldbl-128ibm/lgamma_negl.c (__lgamma_negl):
	Likewise.
	* sysdeps/ieee754/ldbl-128ibm/s_expm1l.c (__expm1l): Likewise.
	* sysdeps/ieee754/ldbl-128ibm/s_truncl.c (__truncl): Likewise.
	* sysdeps/ieee754/ldbl-96/e_lgammal_r.c (sin_pi): Likewise.
	* sysdeps/ieee754/ldbl-96/lgamma_negl.c (__lgamma_negl): Likewise.
	* sysdeps/powerpc/power5+/fpu/s_modf.c (__modf): Likewise.
	* sysdeps/powerpc/power5+/fpu/s_modff.c (__modff): Likewise.
 2018-09-14 13:09:01 +00:00
Joseph Myers
24b6515d87 Add libm_alias_*_other_r macros. 
Some libm functions are unable to use the generic alias macros such as
libm_alias_double because they have special symbol versioning
requirements for the main float, double or long double public names.

To facilitate adding _FloatN / _FloatNx function aliases in future,
it's still desirable to have generic macros those functions can use as
far as possible.  This patch adds macros such as
libm_alias_double_other, which only define names for _FloatN /
_FloatNx aliases, not for float / double / long double.  As present,
all these new macros do nothing, but they are called in the
appropriate places in macros such as libm_alias_double.  This patch
also arranges for lgamma implementations, and the recently added
optimized float function implementations, to use the new macros to
make them ready for addition of _FloatN / _FloatNx aliases.

Tested for x86_64, and tested with build-many-glibcs.py that installed
stripped shared libraries are unchanged by this patch.

	* sysdeps/generic/libm-alias-double.h (libm_alias_double_other_r):
	New macro.
	(libm_alias_double_other): Likewise.
	(libm_alias_double_r): Use libm_alias_double_other_r.
	* sysdeps/generic/libm-alias-float.h (libm_alias_float_other_r):
	New macro.
	(libm_alias_float_other): Likewise.
	(libm_alias_float_r): Use libm_alias_float_other_r.
	* sysdeps/generic/libm-alias-float128.h
	(libm_alias_float128_other_r): New macro.
	(libm_alias_float128_other): Likewise.
	(libm_alias_float128_r): Use libm_alias_float128_other_r.
	* sysdeps/generic/libm-alias-ldouble.h
	(libm_alias_ldouble_other_r): New macro.
	(libm_alias_ldouble_other): Likewise.
	(libm_alias_ldouble_r): Use libm_alias_ldouble_other_r.
	* sysdeps/ieee754/ldbl-opt/libm-alias-double.h
	(libm_alias_double_other_r): New macro.
	(libm_alias_double_other): Likewise.
	(libm_alias_double_r): Use libm_alias_double_other_r.
	* sysdeps/ieee754/ldbl-opt/libm-alias-ldouble.h
	(libm_alias_ldouble_other_r): New macro.
	(libm_alias_ldouble_other): Likewise.
	(libm_alias_ldouble_r): Use libm_alias_ldouble_other_r.
	* math/w_lgamma_main.c: Include <libm-alias-double.h>.
	[!USE_AS_COMPAT]: Use libm_alias_double_other.
	* math/w_lgammaf_main.c: Include <libm-alias-float.h>.
	[!USE_AS_COMPAT]: Use libm_alias_float_other.
	* math/w_lgammal_main.c: Include <libm-alias-ldouble.h>.
	[!USE_AS_COMPAT]: Use libm_alias_ldouble_other.
	* math/w_exp2f.c: Use libm_alias_float_other.
	* math/w_expf.c: Likewise.
	* math/w_log2f.c: Likewise.
	* math/w_logf.c: Likewise.
	* math/w_powf.c: Likewise.
	* sysdeps/ieee754/flt-32/e_exp2f.c: Include <libm-alias-float.h>.
	[!__exp2f]: Use libm_alias_float_other.
	* sysdeps/ieee754/flt-32/e_expf.c: Include <libm-alias-float.h>.
	[!__expf]: Use libm_alias_float_other.
	* sysdeps/ieee754/flt-32/e_log2f.c: Include <libm-alias-float.h>.
	[!__log2f]: Use libm_alias_float_other.
	* sysdeps/ieee754/flt-32/e_logf.c: Include <libm-alias-float.h>.
	[!__logf]: Use libm_alias_float_other.
	* sysdeps/ieee754/flt-32/e_powf.c: Include <libm-alias-float.h>.
	[!__powf]: Use libm_alias_float_other.
 2017-10-10 21:29:11 +00:00
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
Joseph Myers
d709042a6e Fix lgamma setting signgam for ISO C (bug 15421). 
The lgamma (and likewise lgammaf, lgammal) function wrongly sets the
signgam variable even when building for strict ISO C conformance
(-std=c99 / -std=c11), although the user may define such a variable
and it's only in the implementation namespace for POSIX with XSI
extensions enabled.

Following discussions starting at
<https://sourceware.org/ml/libc-alpha/2013-04/msg00767.html> and
<https://sourceware.org/ml/libc-alpha/2015-10/msg00844.html>, it seems
that the safest approach for fixing this particular issue is for
signgam to become a weak alias for a newly exported symbol __signgam,
with the library functions only setting __signgam, at which point
static linker magic will preserve the alias for newly linked binaries
that refer to the library's signgam rather than defining their own,
while breaking the alias for programs that define their own signgam,
with new symbol versions for lgamma functions and with compat symbols
for existing binaries that set both signgam and __signgam.

This patch implements that approach for the fix.  signgam is made into
a weak alias.  The four symbols __signgam, lgamma, lgammaf, lgammal
get new symbol versions at version GLIBC_2.23, with the existing
versions of lgamma, lgammaf and lgammal becoming compat symbols.

When the compat versions are built, gamma, gammaf and gammal are
aliases for the compat versions (i.e. always set signgam); this is OK
as they are not ISO C functions, and avoids adding new symbol versions
for them unnecessarily.  When the compat versions are not built
(i.e. for static linking and for future glibc ports), gamma, gammaf
and gammal are aliases for the new versions that set __signgam.  The
ldbl-opt versions are updated accordingly.

The lgamma wrappers are adjusted so that the same source files,
included from different files with different definitions of
USE_AS_COMPAT, can build either the new versions or the compat
versions.  Similar changes are made to the ia64 versions (untested).

Tests are added that the lgamma functions do not interfere with a user
variable called signgam for ISO C, with various choices for the size
of that variable, whether it is initialized, and for static and
dynamic linking.  The conformtest whitelist entry is removed as well.

Tested for x86_64, x86, mips64 and powerpc, including looking at
objdump --dynamic-syms output to make sure the expected sets of
symbols were aliases.  Also spot-tested that a binary built with old
glibc works properly (i.e. gets signgam set) when run with new glibc.

	[BZ #15421]
	* sysdeps/ieee754/s_signgam.c (signgam): Rename to __signgam,
	initialize with 0 and define as weak alias of __signgam.
	* include/math.h [!_ISOMAC] (__signgam): Declare.
	* math/Makefile (libm-calls): Add w_lgamma_compat.
	(tests): Add test-signgam-uchar, test-signgam-uchar-init,
	test-signgam-uint, test-signgam-uint-init, test-signgam-ullong and
	test-signgam-ullong-init.
	(tests-static): Add test-signgam-uchar-static,
	test-signgam-uchar-init-static, test-signgam-uint-static,
	test-signgam-uint-init-static, test-signgam-ullong-static and
	test-signgam-ullong-init-static.
	(CFLAGS-test-signgam-uchar.c): New variable.
	(CFLAGS-test-signgam-uchar-init.c): Likewise.
	(CFLAGS-test-signgam-uchar-static.c): Likewise.
	(CFLAGS-test-signgam-uchar-init-static.c): Likewise.
	(CFLAGS-test-signgam-uint.c): Likewise.
	(CFLAGS-test-signgam-uint-init.c): Likewise.
	(CFLAGS-test-signgam-uint-static.c): Likewise.
	(CFLAGS-test-signgam-uint-init-static.c): Likewise.
	(CFLAGS-test-signgam-ullong.c): Likewise.
	(CFLAGS-test-signgam-ullong-init.c): Likewise.
	(CFLAGS-test-signgam-ullong-static.c): Likewise.
	(CFLAGS-test-signgam-ullong-init-static.c): Likewise.
	* math/Versions (libm): Add GLIBC_2.23.
	* math/lgamma-compat.h: New file.
	* math/test-signgam-main.c: Likewise.
	* math/test-signgam-uchar-init-static.c: Likewise.
	* math/test-signgam-uchar-init.c: Likewise.
	* math/test-signgam-uchar-static.c: Likewise.
	* math/test-signgam-uchar.c: Likewise.
	* math/test-signgam-uint-init-static.c: Likewise.
	* math/test-signgam-uint-init.c: Likewise.
	* math/test-signgam-uint-static.c: Likewise.
	* math/test-signgam-uint.c: Likewise.
	* math/test-signgam-ullong-init-static.c: Likewise.
	* math/test-signgam-ullong-init.c: Likewise.
	* math/test-signgam-ullong-static.c: Likewise.
	* math/test-signgam-ullong.c: Likewise.
	* math/w_lgamma.c: Rename to w_lgamma_main.c and replace by
	wrapper of w_lgamma_main.c.
	* math/w_lgamma_compat.c: New file.
	* math/w_lgamma_compatf.c: Likewise.
	* math/w_lgamma_compatl.c: Likewise.
	* math/w_lgamma_main.c: New file.  Based on w_lgamma.c.  Include
	<lgamma-compat.h>.  Condition contents on [BUILD_LGAMMA].  Support
	defining compatibility symbols.
	(__lgamma): Change to LGFUNC (__lgamma).  Use CALL_LGAMMA.
	* math/w_lgammaf.c: Rename to w_lgammaf_main.c and replace by
	wrapper of w_lgammaf_main.c.
	* math/w_lgammaf_main.c: New file.  Based on w_lgammaf.c.  Include
	<lgamma-compat.h>.  Condition contents on [BUILD_LGAMMA].  Support
	defining compatibility symbols.
	(__lgammaf): Change to LGFUNC (__lgammaf).  Use CALL_LGAMMA.
	* math/w_lgammal.c: Rename to w_lgammal_main.c and replace by
	wrapper of w_lgammal_main.c.
	* math/w_lgammal_main.c: New file.  Based on w_lgammal.c.  Include
	<lgamma-compat.h>.  Condition contents on [BUILD_LGAMMA].  Support
	defining compatibility symbols.
	(__lgammal): Change to LGFUNC (__lgammal).  Use CALL_LGAMMA.
	* sysdeps/ia64/fpu/lgamma-compat.h: New file.
	* sysdeps/ia64/fpu/w_lgamma.c: Move to ....
	* sysdeps/ia64/fpu/w_lgamma_main.c: ...here.  Include
	<lgamma-compat.h>.
	(__ieee754_lgamma): Change to LGFUNC (lgamma).  Use CALL_LGAMMA.
	(__ieee754_gamma): Define as alias.
	* sysdeps/ia64/fpu/w_lgammaf.c: Move to ....
	* sysdeps/ia64/fpu/w_lgammaf_main.c: ...here.  Include
	<lgamma-compat.h>.
	(__ieee754_lgammaf): Change to LGFUNC (lgammaf).  Use CALL_LGAMMA.
	(__ieee754_gammaf): Define as alias.
	* sysdeps/ia64/fpu/w_lgammal.c: Move to ....
	* sysdeps/ia64/fpu/w_lgammal_main.c: ...here.  Include
	<lgamma-compat.h>.
	(__ieee754_lgammal): Change to LGFUNC (lgammal).  Use CALL_LGAMMA.
	(__ieee754_gammal): Define as alias.
	* sysdeps/ieee754/ldbl-opt/w_lgamma.c: Move to ....
	* sysdeps/ieee754/ldbl-opt/w_lgamma_compat.c: ...here.  Include
	<math/w_lgamma_compat.c>.
	[LONG_DOUBLE_COMPAT(libm, GLIBC_2_0)] (__lgammal_dbl_compat):
	Define as alias of __lgamma_compat and use in defining lgammal.
	* sysdeps/ieee754/ldbl-opt/w_lgammal.c: Move to ....
	* sysdeps/ieee754/ldbl-opt/w_lgamma_compatl.c: ...here.  Include
	<math/lgamma-compat.h> and <math/w_lgamma_compatl.c>.
	(USE_AS_COMPAT): New macro.
	(LGAMMA_OLD_VER): Undefine and redefine.
	(lgammal): Do not define here.
	(gammal): Only define here if [GAMMA_ALIAS].
	* conform/linknamespace.pl (@whitelist): Remove signgam.
	* sysdeps/nacl/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/aarch64/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/alpha/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/arm/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/hppa/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/i386/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/ia64/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/m68k/coldfire/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/m68k/m680x0/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/microblaze/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/mips/mips32/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/mips/mips64/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/nios2/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libm.abilist:
	Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libm.abilist:
	Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/libm-le.abilist:
	Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/libm.abilist:
	Likewise.
	* sysdeps/unix/sysv/linux/s390/s390-32/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/s390/s390-64/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/sh/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/sparc/sparc32/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/sparc/sparc64/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libm.abilist:
	Likewise.
	* sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libm.abilist:
	Likewise.
	* sysdeps/unix/sysv/linux/tile/tilepro/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/x86_64/64/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/x86_64/x32/libm.abilist: Likewise.
 2015-11-20 22:49:59 +00:00