dnl -*- shell-script -*-
dnl
dnl Copyright (c) 2004-2005 The Trustees of Indiana University and Indiana
dnl                         University Research and Technology
dnl                         Corporation.  All rights reserved.
dnl Copyright (c) 2004-2006 The University of Tennessee and The University
dnl                         of Tennessee Research Foundation.  All rights
dnl                         reserved.
dnl Copyright (c) 2004-2008 High Performance Computing Center Stuttgart,
dnl                         University of Stuttgart.  All rights reserved.
dnl Copyright (c) 2004-2006 The Regents of the University of California.
dnl                         All rights reserved.
dnl Copyright (c) 2006      Los Alamos National Security, LLC.  All rights
dnl                         reserved. 
dnl Copyright (c) 2007      Sun Microsystems, Inc.  All rights reserved.
dnl Copyright (c) 2008-2009 Cisco Systems, Inc.  All rights reserved.
dnl $COPYRIGHT$
dnl 
dnl Additional copyrights may follow
dnl 
dnl $HEADER$
dnl

# This macro is necessary to get the title to be displayed first.  :-)
AC_DEFUN([OMPI_SETUP_CXX_BANNER],[
    ompi_show_subtitle "C++ compiler and preprocessor" 
])

# This macro is necessary because PROG_CXX* is REQUIREd by multiple
# places in SETUP_CXX.
AC_DEFUN([OMPI_PROG_CXX],[
    OMPI_VAR_SCOPE_PUSH([ompi_cxxflags_save])
    ompi_cxxflags_save="$CXXFLAGS"
    AC_PROG_CXX
    AC_PROG_CXXCPP
    CXXFLAGS="$ompi_cxxflags_save"
    OMPI_VAR_SCOPE_POP
])

# OMPI_SETUP_CXX()
# ----------------
# Do everything required to setup the C++ compiler.  Safe to AC_REQUIRE
# this macro.
AC_DEFUN([OMPI_SETUP_CXX],[
    AC_REQUIRE([OMPI_SETUP_CXX_BANNER])

    _OMPI_SETUP_CXX_COMPILER

    _OMPI_CXX_CHECK_EXCEPTIONS

    AS_IF([test "$WANT_MPI_CXX_SUPPORT" = "1"],
          [OMPI_CXX_FIND_TEMPLATE_REPOSITORY
           OMPI_CXX_FIND_TEMPLATE_PARAMETERS
           OMPI_CHECK_IDENT([CXX], [CXXFLAGS], [cc], [C++])])

    _OMPI_CXX_CHECK_BUILTIN

    _OMPI_CXX_CHECK_2D_CONST_CAST
])

# _OMPI_SETUP_CXX_COMPILER()
# --------------------------
# Setup the CXX compiler
AC_DEFUN([_OMPI_SETUP_CXX_COMPILER],[
    OMPI_VAR_SCOPE_PUSH(ompi_cxx_compiler_works)

    # There's a few cases here:
    #
    # 1. --enable-mpi-cxx was supplied: error if we don't find a C++
    #    compiler
    # 2. --disable-mpi-cxx was supplied: check for a C++ compiler anyway
    #    (so we can have a functional mpic++ wrapper compiler), but
    #    don't error if we don't find one.
    # 3. neither was specified: same was #2
    #
    # Then only proceed to do all the rest of the C++ checks if we
    # both found a c++ compiler and want the C++ bindings (i.e., either
    # case #1 or #3)

    # Must REQUIRE the PROG_CXX macro and not call it directly here for
    # reasons well-described in the AC2.64 (and beyond) docs.
    AC_REQUIRE([OMPI_PROG_CXX])
    BASECXX="`basename $CXX`"

    AS_IF([test "x$CXX" = "x"], [CXX=none])
    set dummy $CXX
    ompi_cxx_argv0=[$]2
    OMPI_WHICH([$ompi_cxx_argv0], [OMPI_CXX_ABSOLUTE])
    AS_IF([test "x$OMPI_CXX_ABSOLUTE" = "x"], [OMPI_CXX_ABSOLUTE=none])

    AC_DEFINE_UNQUOTED(OMPI_CXX, "$CXX", [OMPI underlying C++ compiler])
    AC_SUBST(OMPI_CXX_ABSOLUTE)

    # Make sure that the C++ compiler both works and is actually a C++
    # compiler (if not cross-compiling).  Don't just use the AC macro
    # so that we can have a pretty message.  Do something here that
    # should force the linking of C++-specific things (e.g., STL
    # strings) so that we can force a hard check of compiling,
    # linking, and running a C++ application.  Note that some C
    # compilers, such as at least some versions of the GNU and Intel
    # compilers, will detect that the file extension is ".cc" and
    # therefore switch into a pseudo-C++ personality which works for
    # *compiling*, but does not work for *linking*.  So in this test,
    # we want to cover the entire spectrum (compiling, linking,
    # running).  Note that it is not a fatal error if the C++ compiler
    # does not work unless the user specifically requested the C++
    # bindings.
    AS_IF([test "$CXX" = "none"],
          [ompi_cxx_compiler_works=no],
          [AS_IF([test "$ompi_cv_cxx_compiler_vendor" = "microsoft" ],
                 [ompi_cxx_compiler_works=yes],
                 [OMPI_CHECK_COMPILER_WORKS([C++], [#include <string>
], 
                                            [std::string foo = "Hello, world"],
                                            [ompi_cxx_compiler_works=yes],
                                            [ompi_cxx_compiler_works=no])])])

    AS_IF([test "$ompi_cxx_compiler_works" = "yes"],
          [_OMPI_SETUP_CXX_COMPILER_BACKEND],
          [AS_IF([test "$enable_mpi_cxx" = "yes"],
                 [AC_MSG_WARN([Could not find functional C++ compiler, but])
                  AC_MSG_WARN([support for the C++ MPI bindings was requested.])
                  AC_MSG_ERROR([Cannot continue])],
                 [WANT_MPI_CXX_SUPPORT=0])])

    AC_MSG_CHECKING([if able to build the MPI C++ bindings])
    AS_IF([test "$WANT_MPI_CXX_SUPPORT" = "1"],
          [AC_MSG_RESULT([yes])], 
          [AC_MSG_RESULT([no])
           AS_IF([test "$enable_mpi_cxx" = "yes"],
                 [AC_MSG_WARN([MPI C++ binding support requested but not delivered])
                  AC_MSG_ERROR([Cannot continue])])])

    AS_IF([test "$WANT_MPI_CXX_SUPPORT" = "1"],
          [OMPI_CXX_COMPILER_VENDOR([ompi_cxx_vendor])])
    OMPI_VAR_SCOPE_POP
])

# _OMPI_SETUP_CXX_COMPILER_BACKEND()
# ----------------------------------
# Back end of _OMPI_SETUP_CXX_COMPILER_BACKEND()
AC_DEFUN([_OMPI_SETUP_CXX_COMPILER_BACKEND],[
    # Do we want code coverage
    if test "$WANT_COVERAGE" = "1"; then 
        if test "$ompi_cxx_vendor" = "gnu" ; then
            AC_MSG_WARN([$OMPI_COVERAGE_FLAGS has been added to CFLAGS (--enable-coverage)])
            WANT_DEBUG=1
            CXXFLAGS="${CXXFLAGS} $OMPI_COVERAGE_FLAGS"
            WRAPPER_EXTRA_CXXFLAGS="${WRAPPER_EXTRA_CXXFLAGS} $OMPI_COVERAGE_FLAGS"
        else
            AC_MSG_WARN([Code coverage functionality is currently available only with GCC suite])
            AC_MSG_ERROR([Configure: cannot continue])
        fi
    fi

    # Do we want debugging?
    if test "$WANT_DEBUG" = "1" -a "$enable_debug_symbols" != "no" ; then
        CXXFLAGS="$CXXFLAGS -g"
        OMPI_UNIQ(CXXFLAGS)
        AC_MSG_WARN([-g has been added to CXXFLAGS (--enable-debug)])
    fi

    # These flags are generally g++-specific; even the g++-impersonating
    # compilers won't accept them.
    OMPI_CXXFLAGS_BEFORE_PICKY="$CXXFLAGS"
    if test "$WANT_PICKY_COMPILER" = 1 -a "$ompi_cxx_vendor" = "gnu"; then
        add="-Wall -Wundef -Wno-long-long"

        # see if -Wno-long-double works...
        AC_LANG_PUSH(C++)
        CXXFLAGS_orig="$CXXFLAGS"
        CXXFLAGS="$CXXFLAGS $add -Wno-long-double -fstrict-prototype"
        AC_CACHE_CHECK([if $CXX supports -Wno-long-double],
                   [ompi_cv_cxx_wno_long_double],
                   [AC_TRY_COMPILE([], [], 
                                   [ompi_cv_cxx_wno_long_double="yes"],
                                   [ompi_cv_cxx_wno_long_double="no"])])
        CXXFLAGS="$CXXFLAGS_orig"
        AC_LANG_POP(C++)
        if test "$ompi_cv_cxx_wno_long_double" = "yes" ; then
            add="$add -Wno-long-double"
        fi

        CXXFLAGS="$CXXFLAGS $add"
        OMPI_UNIQ(CXXFLAGS)
        if test "$add" != "" ; then
            AC_MSG_WARN([$add has been added to CXXFLAGS (--enable-picky)])
        fi
        unset add
    fi

    # See if this version of g++ allows -finline-functions
    if test "$GXX" = "yes"; then
        CXXFLAGS_orig="$CXXFLAGS"
        CXXFLAGS="$CXXFLAGS -finline-functions"
        add=
        AC_CACHE_CHECK([if $CXX supports -finline-functions],
                   [ompi_cv_cxx_finline_functions],
                   [AC_TRY_COMPILE([], [],
                                   [ompi_cv_cxx_finline_functions="yes"],
                                   [ompi_cv_cxx_finline_functions="no"])])
        if test "$ompi_cv_cxx_finline_functions" = "yes" ; then
            add=" -finline-functions"
        fi
        CXXFLAGS="$CXXFLAGS_orig$add"
        OMPI_UNIQ(CXXFLAGS)
        if test "$add" != "" ; then
            AC_MSG_WARN([$add has been added to CXXFLAGS])
        fi
        unset add
    fi

    # Make sure we can link with the C compiler
    if[ test "$ompi_cv_cxx_compiler_vendor" != "microsoft" ]; then
      OMPI_LANG_LINK_WITH_C([C++], [],
        [cat <<EOF >&2
**********************************************************************
* It appears that your C++ compiler is unable to link against object
* files created by your C compiler.  This generally indicates either
* a conflict between the options specified in CFLAGS and CXXFLAGS
* or a problem with the local compiler installation.  More
* information (including exactly what command was given to the 
* compilers and what error resulted when the commands were executed) is
* available in the config.log file in this directory.
**********************************************************************
EOF
         AC_MSG_ERROR([C and C++ compilers are not link compatible.  Can not continue.])])
    fi

    # If we are on HP-UX, ensure that we're using aCC
    case "$host" in
    *hpux*)
        if test "$BASECXX" = "CC"; then
            AC_MSG_WARN([*** You will probably have problems compiling the MPI 2])
            AC_MSG_WARN([*** C++ bindings with the HP-UX CC compiler.  You should])
            AC_MSG_WARN([*** probably be using the aCC compiler.  Re-run configure])
            AC_MSG_WARN([*** with the environment variable "CXX=aCC".])
        fi
        ;;
    esac

    # Note: gcc-imperonating compilers accept -O3
    if test "$WANT_DEBUG" = "1"; then
        OPTFLAGS=
    else
        if test "$GXX" = yes; then
            OPTFLAGS="-O3"
        else
            OPTFLAGS="-O"
        fi
    fi

    # config/ompi_check_optflags.m4
    OMPI_CHECK_OPTFLAGS(["$CXXFLAGS"])
    AC_MSG_CHECKING([for C++ optimization flags])
    AC_MSG_RESULT([$co_result])
    CXXFLAGS="$co_result"

    # bool type size and alignment
    AC_LANG_PUSH(C++)
    AC_CHECK_SIZEOF(bool)
    OMPI_C_GET_ALIGNMENT(bool, OPAL_ALIGNMENT_CXX_BOOL)
    AC_LANG_POP(C++)
])


# _OMPI_CXX_CHECK_EXCEPTIONS()
# ----------------------------
# Check for exceptions, skipping the test if we don't want the C++
# bindings
AC_DEFUN([_OMPI_CXX_CHECK_EXCEPTIONS],[
    # Check for special things due to C++ exceptions
    ENABLE_CXX_EXCEPTIONS=no
    HAVE_CXX_EXCEPTIONS=0
    AC_ARG_ENABLE([cxx-exceptions], 
        [AC_HELP_STRING([--enable-cxx-exceptions],
	                [enable support for C++ exceptions (default: disabled)])],
        [ENABLE_CXX_EXCEPTIONS="$enableval"])

    AC_MSG_CHECKING([if want C++ exception handling])

    AS_IF([test "$WANT_MPI_CXX_SUPPORT" = "0"],
          [AS_IF([test "$$enable_cxx_exceptions" = "yes"],
                 [AC_MSG_RESULT([error])
                  AC_MSG_WARN([--enable-cxx-exceptions was specified, but the MPI C++ bindings were disabled])
                  AC_MSG_ERROR([Cannot continue])],
                 [AC_MSG_RESULT([skipped])])],
          [_OMPI_CXX_CHECK_EXCEPTIONS_BACKEND])

    AC_DEFINE_UNQUOTED(OMPI_HAVE_CXX_EXCEPTION_SUPPORT, $HAVE_CXX_EXCEPTIONS,
        [Whether or not we have compiled with C++ exceptions support])
])

# _OMPI_CXX_CHECK_EXCEPTIONS_BACKEND()
# ------------------------------------
# Back end of _OMPI_CXX_CHECK_EXCEPTIONS
AC_DEFUN([_OMPI_CXX_CHECK_EXCEPTIONS_BACKEND],[
    AC_MSG_RESULT([$ENABLE_CXX_EXCEPTIONS])
    if test "$ENABLE_CXX_EXCEPTIONS" = "yes"; then
        # config/cxx_have_exceptions.m4
        OMPI_CXX_HAVE_EXCEPTIONS
        # config/cxx_find_exception_flags.m4
        OMPI_CXX_FIND_EXCEPTION_FLAGS
        if test "$OMPI_CXX_EXCEPTIONS" = "1"; then
            HAVE_CXX_EXCEPTIONS=1

            # Test to see if the C compiler likes these flags
            AC_MSG_CHECKING([to see if C compiler likes the exception flags])
            CFLAGS="$CFLAGS $OMPI_CXX_EXCEPTIONS_CXXFLAGS"
            AC_LANG_SAVE
            AC_LANG_C
            AC_COMPILE_IFELSE(AC_LANG_PROGRAM([[]], [[int i = 0;]]),
                              [AC_MSG_RESULT([yes])],
                              [AC_MSG_RESULT([no])
                               AC_MSG_WARN([C++ exception flags are different between the C and C++ compilers; this configure script cannot currently handle this scenario.  Either disable C++ exception support or send mail to the Open MPI users list.])
                               AC_MSG_ERROR([*** Cannot continue])])
            AC_LANG_RESTORE

            # We can't test the F77 and F90 compilers now because we
            # haven't found/set the up yet.  So just save the flags
            # and test them later (in ompi_setup_f77.m4 and
            # ompi_setup_f90.m4).

            CXXFLAGS="$CXXFLAGS $OMPI_CXX_EXCEPTIONS_CXXFLAGS"
            LDFLAGS="$LDFLAGS $OMPI_CXX_EXCEPTIONS_LDFLAGS"

            WRAPPER_EXTRA_CFLAGS="$OMPI_CXX_EXCEPTIONS_CXXFLAGS ${WRAPPER_EXTRA_CFLAGS}"
            WRAPPER_EXTRA_FFLAGS="$OMPI_CXX_EXCEPTIONS_CXXFLAGS ${WRAPPER_EXTRA_FFLAGS}"
            WRAPPER_EXTRA_FCFLAGS="$OMPI_CXX_EXCEPTIONS_CXXFLAGS ${WRAPPER_EXTRA_FCFLAGS}"
            WRAPPER_EXTRA_CXXFLAGS="$OMPI_CXX_EXCEPTIONS_CXXFLAGS ${WRAPPER_EXTRA_CXXFLAGS}"
        fi
    fi
])

# _OMPI_CXX_CHECK_BUILTIN
# -----------------------
# Check for __builtin_* stuff
AC_DEFUN([_OMPI_CXX_CHECK_BUILTIN],[
    OMPI_VAR_SCOPE_PUSH([have_cxx_builtin_expect have_cxx_builtin_prefetch])
    have_cxx_builtin_expect=0
    have_cxx_builtin_prefetch=0

    AS_IF([test "$WANT_MPI_CXX_SUPPORT" = "1"],
          [_OMPI_CXX_CHECK_BUILTIN_BACKEND])

    AC_DEFINE_UNQUOTED([OMPI_CXX_HAVE_BUILTIN_EXPECT], 
                       [$have_cxx_builtin_expect],
                       [Whether C++ compiler supports __builtin_expect])
    AC_DEFINE_UNQUOTED([OMPI_CXX_HAVE_BUILTIN_PREFETCH], 
                       [$have_cxx_builtin_prefetch],
                       [Whether C++ compiler supports __builtin_prefetch])

    OMPI_VAR_SCOPE_POP
])

# _OMPI_CXX_CHECK_BUILTIN_BACKEND
# -------------------------------
# Back end of _OMPI_CXX_CHECK_BUILTIN
AC_DEFUN([_OMPI_CXX_CHECK_BUILTIN_BACKEND],[

    # see if the C++ compiler supports __builtin_expect
    AC_LANG_PUSH(C++)
    AC_CACHE_CHECK([if $CXX supports __builtin_expect],
        [ompi_cv_cxx_supports___builtin_expect],
        [AC_TRY_LINK([],
          [void *ptr = (void*) 0;
           if (__builtin_expect (ptr != (void*) 0, 1)) return 0;],
          [ompi_cv_cxx_supports___builtin_expect="yes"],
          [ompi_cv_cxx_supports___builtin_expect="no"])])
    if test "$ompi_cv_cxx_supports___builtin_expect" = "yes" ; then
        have_builtin_expect=1
    fi
    AC_LANG_POP(C++)

    # see if the C compiler supports __builtin_prefetch
    AC_LANG_PUSH(C++)
    AC_CACHE_CHECK([if $CXX supports __builtin_prefetch],
        [ompi_cv_cxx_supports___builtin_prefetch],
        [AC_TRY_LINK([],
          [int ptr;
           __builtin_prefetch(&ptr,0,0);],
          [ompi_cv_cxx_supports___builtin_prefetch="yes"],
          [ompi_cv_cxx_supports___builtin_prefetch="no"])])
    if test "$ompi_cv_cxx_supports___builtin_prefetch" = "yes" ; then
        have_builtin_prefetch=1
    fi
    AC_LANG_POP(C++)
])


# _OMPI_CXX_CHECK_2D_CONST_CAST
# -----------------------------
# Check for compiler support of 2D const casts
AC_DEFUN([_OMPI_CXX_CHECK_2D_CONST_CAST],[
    OMPI_VAR_SCOPE_PUSH([use_2d_const_cast])
    use_2d_const_cast=0

    AS_IF([test "$WANT_MPI_CXX_SUPPORT" = "1"],
          [_OMPI_CXX_CHECK_2D_CONST_CAST_BACKEND])

    AC_DEFINE_UNQUOTED([OMPI_CXX_SUPPORTS_2D_CONST_CAST],
                       [$use_2d_const_cast],
                       [Whether a const_cast on a 2-d array will work with the C++ compiler])

    OMPI_VAR_SCOPE_POP
])

# _OMPI_CXX_CHECK_2D_CONST_CAST_BACKEND
# ---------------------------------
# Back end of _OMPI_CHECK_2D_CONST_CAST
AC_DEFUN([_OMPI_CXX_CHECK_2D_CONST_CAST_BACKEND],[
    # see if the compiler supports const_cast of 2-dimensional arrays
    AC_LANG_PUSH(C++)
    AC_CACHE_CHECK([if $CXX supports const_cast<> properly],
       [ompi_cv_cxx_supports_2d_const_cast],
       [AC_TRY_COMPILE([int non_const_func(int ranges[][3]);
int cast_test(const int ranges[][3]) {
  return non_const_func(const_cast<int(*)[3]>(ranges));  
}],
            [],
            [ompi_cv_cxx_supports_2d_const_cast="yes"],
            [ompi_cv_cxx_supports_2d_const_cast="no"])])
    if test "$ompi_cv_cxx_supports_2d_const_cast" = "yes" ; then
        use_2d_const_cast=1
    fi
    AC_LANG_POP(C++)
])