Final 2.9 tag with updated docs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/tags/RELEASE_29@129056 91177308-0d34-0410-b5e6-96231b3b80d8

final/autoconf/m4/link_options.m4

@@ -0,0 +1,108 @@
+#
+# 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-\([^ ]*\)#\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 "$llvm_cv_link_use_r" = yes ; then
+  AC_DEFINE([HAVE_LINK_R],[1],[Define if you can use -Wl,-R. to pass -R. to the linker, in order to add the current directory to the dynamic linker search path.])
+  fi
+])
+
+#
+# Determine if the system can handle the -R option being passed to the linker.
+#
+# This macro is specific to LLVM.
+#
+AC_DEFUN([AC_LINK_EXPORT_DYNAMIC],
+[AC_CACHE_CHECK([for compiler -Wl,-export-dynamic option],
+                [llvm_cv_link_use_export_dynamic],
+[ AC_LANG_PUSH([C])
+  oldcflags="$CFLAGS"
+  CFLAGS="$CFLAGS -Wl,-export-dynamic"
+  AC_LINK_IFELSE([AC_LANG_PROGRAM([[]],[[]])],
+    [llvm_cv_link_use_export_dynamic=yes],[llvm_cv_link_use_export_dynamic=no])
+  CFLAGS="$oldcflags"
+  AC_LANG_POP([C])
+])
+if test "$llvm_cv_link_use_export_dynamic" = yes ; then
+  AC_DEFINE([HAVE_LINK_EXPORT_DYNAMIC],[1],[Define if you can use -Wl,-export-dynamic.])
+  fi
+])
+
+#
+# Determine if the system can handle the --version-script option being
+# passed to the linker.
+#
+# This macro is specific to LLVM.
+#
+AC_DEFUN([AC_LINK_VERSION_SCRIPT],
+[AC_CACHE_CHECK([for compiler -Wl,--version-script option],
+                [llvm_cv_link_use_version_script],
+[ AC_LANG_PUSH([C])
+  oldcflags="$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
+])
+