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llvm-mirror/autoconf/m4/link_options.m4
Bob Wilson 313eeb0a47 Link with -rdynamic instead of -Wl,-export-dynamic.
Recent versions of the OS X linker support this but follow the existing
OS X linker convention of using an underscore in the option name, i.e.,
-export_dynamic. Rather than changing our configure scripts to check for
that alternate spelling, it is simpler to just use the compiler's -rdynamic
option and let it deal with translating that to the appropriate linker
option. One potential disadvantage of this approach is that the compiler
will typically ignore -rdynamic on platforms where it is not supported, so
the HAVE_LINK_EXPORT_DYNAMIC in config.h will not necessarily show whether
that option has any effect or not. I don't see any in-tree uses of that
macro, so I'm assuming it is OK.

llvm-svn: 187686
2013-08-02 22:51:06 +00:00

110 lines
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#
# Get the linker version string.
#
# This macro is specific to LLVM.
#
AC_DEFUN([AC_LINK_GET_VERSION],
[AC_CACHE_CHECK([for linker version],[llvm_cv_link_version],
[
version_string="$(ld -v 2>&1 | head -1)"
# Check for ld64.
if (echo "$version_string" | grep -q "ld64"); then
llvm_cv_link_version=$(echo "$version_string" | sed -e "s#.*ld64-\([^ ]*\)\( (.*)\)\{0,1\}#\1#")
else
llvm_cv_link_version=$(echo "$version_string" | sed -e "s#[^0-9]*\([0-9.]*\).*#\1#")
fi
])
AC_DEFINE_UNQUOTED([HOST_LINK_VERSION],"$llvm_cv_link_version",
[Linker version detected at compile time.])
])
#
# Determine if the system can handle the -R option being passed to the linker.
#
# This macro is specific to LLVM.
#
AC_DEFUN([AC_LINK_USE_R],
[AC_CACHE_CHECK([for compiler -Wl,-R<path> option],[llvm_cv_link_use_r],
[ AC_LANG_PUSH([C])
oldcflags="$CFLAGS"
CFLAGS="$CFLAGS -Wl,-R."
AC_LINK_IFELSE([AC_LANG_PROGRAM([[]],[[]])],
[llvm_cv_link_use_r=yes],[llvm_cv_link_use_r=no])
CFLAGS="$oldcflags"
AC_LANG_POP([C])
])
if test "$llvm_cv_link_use_r" = yes ; then
AC_DEFINE([HAVE_LINK_R],[1],[Define if you can use -Wl,-R. to pass -R. to the linker, in order to add the current directory to the dynamic linker search path.])
fi
])
#
# Determine if the system can handle the -rdynamic option being passed
# to the compiler.
#
# This macro is specific to LLVM.
#
AC_DEFUN([AC_LINK_EXPORT_DYNAMIC],
[AC_CACHE_CHECK([for compiler -rdynamic option],
[llvm_cv_link_use_export_dynamic],
[ AC_LANG_PUSH([C])
oldcflags="$CFLAGS"
CFLAGS="$CFLAGS -rdynamic"
AC_LINK_IFELSE([AC_LANG_PROGRAM([[]],[[]])],
[llvm_cv_link_use_export_dynamic=yes],[llvm_cv_link_use_export_dynamic=no])
CFLAGS="$oldcflags"
AC_LANG_POP([C])
])
if test "$llvm_cv_link_use_export_dynamic" = yes ; then
AC_DEFINE([HAVE_LINK_EXPORT_DYNAMIC],[1],[Define if you can use -rdynamic.])
fi
])
#
# Determine if the system can handle the --version-script option being
# passed to the linker.
#
# This macro is specific to LLVM.
#
AC_DEFUN([AC_LINK_VERSION_SCRIPT],
[AC_CACHE_CHECK([for compiler -Wl,--version-script option],
[llvm_cv_link_use_version_script],
[ AC_LANG_PUSH([C])
oldcflags="$CFLAGS"
# The following code is from the autoconf manual,
# "11.13: Limitations of Usual Tools".
# Create a temporary directory $tmp in $TMPDIR (default /tmp).
# Use mktemp if possible; otherwise fall back on mkdir,
# with $RANDOM to make collisions less likely.
: ${TMPDIR=/tmp}
{
tmp=`
(umask 077 && mktemp -d "$TMPDIR/fooXXXXXX") 2>/dev/null
` &&
test -n "$tmp" && test -d "$tmp"
} || {
tmp=$TMPDIR/foo$$-$RANDOM
(umask 077 && mkdir "$tmp")
} || exit $?
echo "{" > "$tmp/export.map"
echo " global: main;" >> "$tmp/export.map"
echo " local: *;" >> "$tmp/export.map"
echo "};" >> "$tmp/export.map"
CFLAGS="$CFLAGS -Wl,--version-script=$tmp/export.map"
AC_LINK_IFELSE([AC_LANG_PROGRAM([[]],[[]])],
[llvm_cv_link_use_version_script=yes],[llvm_cv_link_use_version_script=no])
rm "$tmp/export.map"
rmdir "$tmp"
CFLAGS="$oldcflags"
AC_LANG_POP([C])
])
if test "$llvm_cv_link_use_version_script" = yes ; then
AC_SUBST(HAVE_LINK_VERSION_SCRIPT,1)
fi
])