# - Add a given compiler flag to flags variables.
# AddCompilerFlag(<flag> [<var>])
# or
# AddCompilerFlag(<flag> [C_FLAGS <var>] [CXX_FLAGS <var>] [C_RESULT <var>]
#                        [CXX_RESULT <var>])

#=============================================================================
# Copyright 2010-2015 Matthias Kretz <kretz@kde.org>
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
#  * Redistributions of source code must retain the above copyright notice,
#    this list of conditions and the following disclaimer.
#
#  * Redistributions in binary form must reproduce the above copyright notice,
#    this list of conditions and the following disclaimer in the documentation
#    and/or other materials provided with the distribution.
#
#  * Neither the names of contributing organizations nor the
#    names of its contributors may be used to endorse or promote products
#    derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS ``AS IS''
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE FOR
# ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#=============================================================================

get_filename_component(_currentDir "${CMAKE_CURRENT_LIST_FILE}" PATH)
include("${_currentDir}/CheckCCompilerFlag.cmake")
include("${_currentDir}/CheckCXXCompilerFlag.cmake")

macro(AddCompilerFlag _flag)
    string(REGEX REPLACE "[-.+/:= ;]" "_" _flag_esc "${_flag}")

    set(_c_flags "CMAKE_C_FLAGS")
    set(_cxx_flags "CMAKE_CXX_FLAGS")
    set(_c_result tmp)
    set(_cxx_result tmp)
    if (${ARGC} EQUAL 2)
        message(WARNING "Deprecated use of the AddCompilerFlag macro.")
        unset(_c_result)
        set(_cxx_result ${ARGV1})
    elseif (${ARGC} GREATER 2)
        set(state 0)
        unset(_c_flags)
        unset(_cxx_flags)
        unset(_c_result)
        unset(_cxx_result)
        foreach (_arg ${ARGN})
            if ("x${_arg}" STREQUAL "xC_FLAGS")
                set(state 1)
                if (NOT DEFINED _c_result)
                    set(_c_result tmp0)
                endif ()
            elseif ("x${_arg}" STREQUAL "xCXX_FLAGS")
                set(state 2)
                if (NOT DEFINED _cxx_result)
                    set(_cxx_result tmp1)
                endif ()
            elseif ("x${_arg}" STREQUAL "xC_RESULT")
                set(state 3)
            elseif ("x${_arg}" STREQUAL "xCXX_RESULT")
                set(state 4)
            elseif (state EQUAL 1)
                set(_c_flags "${_arg}")
            elseif (state EQUAL 2)
                set(_cxx_flags "${_arg}")
            elseif (state EQUAL 3)
                set(_c_result "${_arg}")
            elseif (state EQUAL 4)
                set(_cxx_result "${_arg}")
            else ()
                message(FATAL_ERROR "Syntax error for AddCompilerFlag")
            endif ()
        endforeach ()
    endif ()

    set(_c_code "int main() { return 0; }")
    set(_cxx_code "int main() { return 0; }")
    if ("${_flag}" STREQUAL "-mfma")
        # Compiling with FMA3 support may fail only at the assembler level.
        # In that case we need to have such an instruction in the test code
        set(_c_code "#include <immintrin.h>
      __m128 foo(__m128 x) { return _mm_fmadd_ps(x, x, x); }
      int main() { return 0; }")
        set(_cxx_code "${_c_code}")
    elseif ("${_flag}" STREQUAL "-std=c++14" OR "${_flag}" STREQUAL "-std=c++1y")
        set(_cxx_code "#include <utility>
      struct A { friend auto f(); };
      template <int N> constexpr int var_temp = N;
      template <std::size_t... I> void foo(std::index_sequence<I...>) {}
      int main() { foo(std::make_index_sequence<4>()); return 0; }")
    elseif ("${_flag}" STREQUAL "-std=c++17" OR "${_flag}" STREQUAL "-std=c++1z")
        set(_cxx_code "#include <functional>
      int main() { return 0; }")
    elseif ("${_flag}" STREQUAL "-stdlib=libc++")
        # Compiling with libc++ not only requires a compiler that understands it, but also
        # the libc++ headers itself
        set(_cxx_code "#include <iostream>
      #include <cstdio>
      int main() { return 0; }")
    elseif ("${_flag}" STREQUAL "-march=knl"
            OR "${_flag}" STREQUAL "-march=skylake-avx512"
            OR "${_flag}" STREQUAL "/arch:AVX512"
            OR "${_flag}" STREQUAL "/arch:KNL"
            OR "${_flag}" MATCHES "^-mavx512.")
        # Make sure the intrinsics are there
        set(_cxx_code "#include <immintrin.h>
      __m512 foo(__m256 v) {
        return _mm512_castpd_ps(_mm512_insertf64x4(_mm512_setzero_pd(), _mm256_castps_pd(v), 0x0));
      }
      __m512i bar() { return _mm512_setzero_si512(); }
      int main() { return 0; }")
    elseif ("${_flag}" STREQUAL "-mno-sse" OR "${_flag}" STREQUAL "-mno-sse2")
        set(_cxx_code "#include <cstdio>
      #include <cstdlib>
      int main() { return std::atof(\"0\"); }")
    else ()
        set(_cxx_code "#include <cstdio>
      int main() { return 0; }")
    endif ()

    if (DEFINED _c_result)
        check_c_compiler_flag("${_flag}" check_c_compiler_flag_${_flag_esc} "${_c_code}")
        set(${_c_result} ${check_c_compiler_flag_${_flag_esc}})
    endif ()
    if (DEFINED _cxx_result)
        check_cxx_compiler_flag("${_flag}" check_cxx_compiler_flag_${_flag_esc} "${_cxx_code}")
        set(${_cxx_result} ${check_cxx_compiler_flag_${_flag_esc}})
    endif ()

    macro(my_append _list _flag _special)
        if ("x${_list}" STREQUAL "x${_special}")
            set(${_list} "${${_list}} ${_flag}")
        else ()
            list(APPEND ${_list} "${_flag}")
        endif ()
    endmacro()

    if (check_c_compiler_flag_${_flag_esc} AND DEFINED _c_flags)
        my_append(${_c_flags} "${_flag}" CMAKE_C_FLAGS)
    endif ()
    if (check_cxx_compiler_flag_${_flag_esc} AND DEFINED _cxx_flags)
        my_append(${_cxx_flags} "${_flag}" CMAKE_CXX_FLAGS)
    endif ()
endmacro(AddCompilerFlag)
