liboqs/config/ax_x86_cpu_supports.m4
2019-07-09 09:58:16 -04:00

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# ============================================================================
# adapted from
# https://www.gnu.org/software/autoconf-archive/ax_gcc_x86_cpu_supports.html
# ============================================================================
#
# SYNOPSIS
#
# AX_X86_CPU_SUPPORTS(X86-INSTRUCTION-SET,
# [ACTION-IF-FOUND],[ACTION-IF-NOT-FOUND])
#
# DESCRIPTION
#
# Checks if the host cpu supports X86-INSTRUCTION-SET. The instruction set
# that can be tested are "mmx, popcnt, sse, sse2, sse3, sse4.1, sse4.2,
# sse4a, avx, avx2, avx512f, fma, fma4, bmi, bmi2". If the instruction set
# is supported by the host cpu, the C preprocessor macro
# USE_XXX_INSTRUCTIONS is set to 1. The XXX is up-cased instruction case
# with dot replaced by underscore. For example, the test for "sse4.2"
# would export USE_SSE4_2_INSTRUCTIONS=1. This macro requires gcc
# extended builtin function "__builtin_cpu_supports" to detect the cpu features.
#
# If the test for the instruction set succeeded, the hook ACTION-IF-FOUND
# would run. Otherwise the hook ACTION-IF-NOT-FOUND would run if
# specified.
#
# See also AX_CHECK_X86_FEATURES, which checks all the possible
# instruction set and export the corresponding CFLAGS.
#
# LICENSE
#
# Copyright (c) 2016 Felix Chern <idryman@gmail.com>
#
# This program is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the
# Free Software Foundation; either version 2 of the License, or (at your
# option) any later version.
#
# This program 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 General
# Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program. If not, see <https://www.gnu.org/licenses/>.
#
# As a special exception, the respective Autoconf Macro's copyright owner
# gives unlimited permission to copy, distribute and modify the configure
# scripts that are the output of Autoconf when processing the Macro. You
# need not follow the terms of the GNU General Public License when using
# or distributing such scripts, even though portions of the text of the
# Macro appear in them. The GNU General Public License (GPL) does govern
# all other use of the material that constitutes the Autoconf Macro.
#
# This special exception to the GPL applies to versions of the Autoconf
# Macro released by the Autoconf Archive. When you make and distribute a
# modified version of the Autoconf Macro, you may extend this special
# exception to the GPL to apply to your modified version as well.
#serial 3
AC_DEFUN([AX_X86_CPU_SUPPORTS],[
AC_REQUIRE([AC_PROG_CC])
AC_LANG_PUSH([C])
AS_VAR_PUSHDEF([x86_feature], [AS_TR_SH([ax_cv_x86_cpu_supports_$1])])
AM_COND_IF([X86_64],[
AC_CACHE_CHECK([for x86 $1 instruction support],
[x86_feature],
[AC_RUN_IFELSE(
[AC_LANG_PROGRAM( [#include <stdlib.h> ],
[ #if defined(__GNUC__) && !defined(__clang__)
__builtin_cpu_init();
#endif
if (__builtin_cpu_supports("$1"))
return 0;
return 1;
]
)],
[x86_feature=yes],
[x86_feature=no]
)]
)
])
AC_LANG_POP([C])
AM_CONDITIONAL(AS_TR_SH(m4_toupper([USE_$1_INSTRUCTIONS])), [test x$x86_feature = xyes]) # ADDED BY OQS
AS_VAR_IF([x86_feature],
[yes],
[
AC_DEFINE(
AS_TR_CPP([USE_$1_INSTRUCTIONS]),
[1],
[Define if $1 instructions are supported]
)
$2
],
[$3]
)
AS_VAR_POPDEF([x86_feature])
])