Add TDE_CXX_COMPILE_STDCXX macro to check and enforce C++ standard.

The macro is a simplified form of AX_CXX_COMPILE_STDCXX from autoconf. To verify the C++ standard supported by the compiler, only the value of the __cplusplus constant defined by the compiler is checked, instead of testing examples of using individual C++ features. Signed-off-by: Slávek Banko <slavek.banko@axis.cz> (cherry picked from commit b9fb6ca397)
3 years ago · 92a6d62b8f
parent f078739d97
commit 92a6d62b8f
1 changed files with 212 additions and 0 deletions
--- a/acinclude.m4.in
+++ b/acinclude.m4.in
@ -6862,3 +6862,215 @@ EOF
    AC_SUBST(LIBSQLITE3) 
  fi
 ])
 # ===========================================================================
 #
 # SYNOPSIS
 #
 #   TDE_CXX_COMPILE_STDCXX(VERSION, [ext|noext], [mandatory|optional])
 #
 # DESCRIPTION
 #
 #   Check for baseline language coverage in the compiler for the specified
 #   version of the C++ standard.  If necessary, add switches to CXX and
 #   CXXCPP to enable support.  VERSION may be '11' (for the C++11 standard)
 #   or '14' (for the C++14 standard).
 #
 #   The second argument, if specified, indicates whether you insist on an
 #   extended mode (e.g. -std=gnu++11) or a strict conformance mode (e.g.
 #   -std=c++11).  If neither is specified, you get whatever works, with
 #   preference for no added switch, and then for an extended mode.
 #
 #   The third argument, if specified 'mandatory' or if left unspecified,
 #   indicates that baseline support for the specified C++ standard is
 #   required and that the macro should error out if no mode with that
 #   support is found.  If specified 'optional', then configuration proceeds
 #   regardless, after defining HAVE_CXX${VERSION} if and only if a
 #   supporting mode is found.
 #
 # LICENSE
 #
 #   Copyright (c) 2008 Benjamin Kosnik <bkoz@redhat.com>
 #   Copyright (c) 2012 Zack Weinberg <zackw@panix.com>
 #   Copyright (c) 2013 Roy Stogner <roystgnr@ices.utexas.edu>
 #   Copyright (c) 2014, 2015 Google Inc.; contributed by Alexey Sokolov <sokolov@google.com>
 #   Copyright (c) 2015 Paul Norman <penorman@mac.com>
 #   Copyright (c) 2015 Moritz Klammler <moritz@klammler.eu>
 #   Copyright (c) 2016, 2018 Krzesimir Nowak <qdlacz@gmail.com>
 #   Copyright (c) 2019 Enji Cooper <yaneurabeya@gmail.com>
 #   Copyright (c) 2020 Jason Merrill <jason@redhat.com>
 #   Copyright (c) 2021 Slávek Banko <slavek.banko@axis.cz>
 #
 #   Copying and distribution of this file, with or without modification, are
 #   permitted in any medium without royalty provided the copyright notice
 #   and this notice are preserved.  This file is offered as-is, without any
 #   warranty.
 dnl  This macro is simplified version of the macro AX_CXX_COMPILE_STDCXX
 AC_DEFUN([TDE_CXX_COMPILE_STDCXX], [dnl
  m4_if([$1], [11], [tde_cxx_compile_alternatives="11 0x"],
        [$1], [14], [tde_cxx_compile_alternatives="14 1y"],
        [$1], [17], [tde_cxx_compile_alternatives="17 1z"],
        [m4_fatal([invalid first argument `$1' to TDE_CXX_COMPILE_STDCXX])])dnl
  m4_if([$2], [], [],
        [$2], [ext], [],
        [$2], [noext], [],
        [m4_fatal([invalid second argument `$2' to TDE_CXX_COMPILE_STDCXX])])dnl
  m4_if([$3], [], [tde_cxx_compile_cxx$1_required=true],
        [$3], [mandatory], [tde_cxx_compile_cxx$1_required=true],
        [$3], [optional], [tde_cxx_compile_cxx$1_required=false],
        [m4_fatal([invalid third argument `$3' to TDE_CXX_COMPILE_STDCXX])])
  AC_LANG_PUSH([C++])dnl
  ac_success=no
  m4_if([$2], [], [dnl
    AC_CACHE_CHECK(whether $CXX supports C++$1 features by default,
                   tde_cv_cxx_compile_cxx$1,
      [AC_COMPILE_IFELSE([AC_LANG_SOURCE([_TDE_CXX_COMPILE_STDCXX_testbody_$1])],
        [tde_cv_cxx_compile_cxx$1=yes],
        [tde_cv_cxx_compile_cxx$1=no])])
    if test x$tde_cv_cxx_compile_cxx$1 = xyes; then
      ac_success=yes
    fi])
  m4_if([$2], [noext], [], [dnl
  if test x$ac_success = xno; then
    for alternative in ${tde_cxx_compile_alternatives}; do
      switch="-std=gnu++${alternative}"
      cachevar=AS_TR_SH([tde_cv_cxx_compile_cxx$1_$switch])
      AC_CACHE_CHECK(whether $CXX supports C++$1 features with $switch,
                     $cachevar,
        [ac_save_CXX="$CXX"
         CXX="$CXX $switch"
         AC_COMPILE_IFELSE([AC_LANG_SOURCE([_TDE_CXX_COMPILE_STDCXX_testbody_$1])],
          [eval $cachevar=yes],
          [eval $cachevar=no])
         CXX="$ac_save_CXX"])
      if eval test x\$$cachevar = xyes; then
        CXX="$CXX $switch"
        if test -n "$CXXCPP" ; then
          CXXCPP="$CXXCPP $switch"
        fi
        ac_success=yes
        break
      fi
    done
  fi])
  m4_if([$2], [ext], [], [dnl
  if test x$ac_success = xno; then
    dnl HP's aCC needs +std=c++11 according to:
    dnl http://h21007.www2.hp.com/portal/download/files/unprot/aCxx/PDF_Release_Notes/769149-001.pdf
    dnl Cray's crayCC needs "-h std=c++11"
    for alternative in ${tde_cxx_compile_alternatives}; do
      for switch in -std=c++${alternative} +std=c++${alternative} "-h std=c++${alternative}"; do
        cachevar=AS_TR_SH([tde_cv_cxx_compile_cxx$1_$switch])
        AC_CACHE_CHECK(whether $CXX supports C++$1 features with $switch,
                       $cachevar,
          [ac_save_CXX="$CXX"
           CXX="$CXX $switch"
           AC_COMPILE_IFELSE([AC_LANG_SOURCE([_TDE_CXX_COMPILE_STDCXX_testbody_$1])],
            [eval $cachevar=yes],
            [eval $cachevar=no])
           CXX="$ac_save_CXX"])
        if eval test x\$$cachevar = xyes; then
          CXX="$CXX $switch"
          if test -n "$CXXCPP" ; then
            CXXCPP="$CXXCPP $switch"
          fi
          ac_success=yes
          break
        fi
      done
      if test x$ac_success = xyes; then
        break
      fi
    done
  fi])
  AC_LANG_POP([C++])
  if test x$tde_cxx_compile_cxx$1_required = xtrue; then
    if test x$ac_success = xno; then
      AC_MSG_ERROR([*** A compiler with support for C++$1 language features is required.])
    fi
  fi
  if test x$ac_success = xno; then
    HAVE_CXX$1=0
    AC_MSG_NOTICE([No compiler with C++$1 support was found])
  else
    HAVE_CXX$1=1
    AC_DEFINE(HAVE_CXX$1,1,
              [define if the compiler supports basic C++$1 syntax])
  fi
  AC_SUBST(HAVE_CXX$1)
 ])
 dnl  Test body for checking C++11 support
 m4_define([_TDE_CXX_COMPILE_STDCXX_testbody_11],
  _TDE_CXX_COMPILE_STDCXX_testbody_new_in_11
 )
 dnl  Test body for checking C++14 support
 m4_define([_TDE_CXX_COMPILE_STDCXX_testbody_14],
  _TDE_CXX_COMPILE_STDCXX_testbody_new_in_11
  _TDE_CXX_COMPILE_STDCXX_testbody_new_in_14
 )
 m4_define([_TDE_CXX_COMPILE_STDCXX_testbody_17],
  _TDE_CXX_COMPILE_STDCXX_testbody_new_in_11
  _TDE_CXX_COMPILE_STDCXX_testbody_new_in_14
  _TDE_CXX_COMPILE_STDCXX_testbody_new_in_17
 )
 dnl  Tests for new features in C++11
 m4_define([_TDE_CXX_COMPILE_STDCXX_testbody_new_in_11], [[
 #ifndef __cplusplus
 #error "This is not a C++ compiler"
 #elif __cplusplus < 201103L
 #error "This is not a C++11 compiler"
 #endif  // __cplusplus >= 201103L
 ]])
 dnl  Tests for new features in C++14
 m4_define([_TDE_CXX_COMPILE_STDCXX_testbody_new_in_14], [[
 #ifndef __cplusplus
 #error "This is not a C++ compiler"
 #elif __cplusplus < 201402L
 #error "This is not a C++14 compiler"
 #endif  // __cplusplus >= 201402L
 ]])
 dnl  Tests for new features in C++17
 m4_define([_TDE_CXX_COMPILE_STDCXX_testbody_new_in_17], [[
 #ifndef __cplusplus
 #error "This is not a C++ compiler"
 #elif __cplusplus < 201703L
 #error "This is not a C++17 compiler"
 #endif  // __cplusplus >= 201703L
 ]])