glibc/math/w_log2_compat.c
Szabolcs Nagy 718d6542f2 Remove the error handling wrapper from log2
Introduce new log2 symbol version that doesn't do SVID compatible error
handling.  The standard errno and fp exception based error handling is
inline in the new code and does not have significant overhead.

The wrapper is disabled for sysdeps/ieee754/dbl-64 by using empty
w_log2.c and enabled for targets with their own log2 implementation by
including math/w_log2.c.

The compatibility symbol version still uses the wrapper with SVID error
handling around the new code.  There is no new symbol version nor
compatibility code on !LIBM_SVID_COMPAT targets (e.g. riscv).

On targets where previously log2l was an alias of log2, now it points to
the compatibility symbol with the wrapper, because it still need the
SVID compatible error handling.  This affects NO_LONG_DOUBLE (e.g. arm)
and LONG_DOUBLE_COMPAT (e.g. alpha) targets as well.

The __log2_finite symbol is now an alias of log2.  Both __log2_finite
and log2 set errno and thus not const functions.

The ia64 asm is changed so the compat and new symbol versions map to the
same address.

Tested with build-many-glibcs.py.

	* math/Versions (GLIBC_2.29): Add log2.
	* math/w_log2_compat.c (__log2_compat): Change to versioned compat
	symbol.
	* math/w_log2.c: New file.
	* sysdeps/i386/fpu/w_log2.c: New file.
	* sysdeps/ia64/fpu/e_log2.S: Add versioned symbols.
	* sysdeps/ieee754/dbl-64/e_log2.c (__ieee754_log2): Rename to __log2
	and add necessary aliases.
	* sysdeps/ieee754/dbl-64/w_log2.c: New file.
	* sysdeps/m68k/m680x0/fpu/w_log2.c: New file.
	* sysdeps/mach/hurd/i386/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/aarch64/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/alpha/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/arm/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/hppa/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/i386/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/ia64/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/m68k/coldfire/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/m68k/m680x0/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/microblaze/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/mips/mips32/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/mips/mips64/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/nios2/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/libm-le.abilist: Update.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/s390/s390-32/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/s390/s390-64/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/sh/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/sparc/sparc32/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/sparc/sparc64/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/x86_64/64/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/x86_64/x32/libm.abilist: Update.
2018-11-21 09:57:21 +00:00

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1.9 KiB
C

/* Copyright (C) 2011-2018 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 <fenv.h>
#include <math.h>
#include <math_private.h>
#include <math-svid-compat.h>
#include <libm-alias-double.h>
#if LIBM_SVID_COMPAT && (SHLIB_COMPAT (libm, GLIBC_2_1, GLIBC_2_29) \
|| defined NO_LONG_DOUBLE \
|| defined LONG_DOUBLE_COMPAT)
/* wrapper log2(x) */
double
__log2_compat (double x)
{
if (__builtin_expect (islessequal (x, 0.0), 0) && _LIB_VERSION != _IEEE_)
{
if (x == 0.0)
{
feraiseexcept (FE_DIVBYZERO);
return __kernel_standard (x, x, 48); /* log2(0) */
}
else
{
feraiseexcept (FE_INVALID);
return __kernel_standard (x, x, 49); /* log2(x<0) */
}
}
return __ieee754_log2 (x);
}
# if SHLIB_COMPAT (libm, GLIBC_2_1, GLIBC_2_29)
compat_symbol (libm, __log2_compat, log2, GLIBC_2_1);
# endif
# ifdef NO_LONG_DOUBLE
weak_alias (__log2_compat, log2l)
# endif
# ifdef LONG_DOUBLE_COMPAT
/* Work around gas bug "multiple versions for symbol". */
weak_alias (__log2_compat, __log2_compat_alias)
LONG_DOUBLE_COMPAT_CHOOSE_libm_log2l (
compat_symbol (libm, __log2_compat_alias, log2l, FIRST_VERSION_libm_log2l), );
# endif
#endif