[thirdparty/gcc.git] / libgomp / acinclude.m4

dnl ----------------------------------------------------------------------
dnl This whole bit snagged from libgfortran.

dnl Check whether the target supports __sync_*_compare_and_swap.
AC_DEFUN([LIBGOMP_CHECK_SYNC_BUILTINS], [
  AC_CACHE_CHECK([whether the target supports __sync_*_compare_and_swap],
		 libgomp_cv_have_sync_builtins, [
  AC_TRY_LINK([], [int foo; __sync_val_compare_and_swap(&foo, 0, 1);],
	      libgomp_cv_have_sync_builtins=yes, libgomp_cv_have_sync_builtins=no)])
  if test $libgomp_cv_have_sync_builtins = yes; then
    AC_DEFINE(HAVE_SYNC_BUILTINS, 1,
	      [Define to 1 if the target supports __sync_*_compare_and_swap])
  fi])

dnl Check whether the target supports hidden visibility.
AC_DEFUN([LIBGOMP_CHECK_ATTRIBUTE_VISIBILITY], [
  AC_CACHE_CHECK([whether the target supports hidden visibility],
		 libgomp_cv_have_attribute_visibility, [
  save_CFLAGS="$CFLAGS"
  CFLAGS="$CFLAGS -Werror"
  AC_TRY_COMPILE([void __attribute__((visibility("hidden"))) foo(void) { }],
		 [], libgomp_cv_have_attribute_visibility=yes,
		 libgomp_cv_have_attribute_visibility=no)
  CFLAGS="$save_CFLAGS"])
  if test $libgomp_cv_have_attribute_visibility = yes; then
    AC_DEFINE(HAVE_ATTRIBUTE_VISIBILITY, 1,
      [Define to 1 if the target supports __attribute__((visibility(...))).])
  fi])

dnl Check whether the target supports dllexport
AC_DEFUN([LIBGOMP_CHECK_ATTRIBUTE_DLLEXPORT], [
  AC_CACHE_CHECK([whether the target supports dllexport],
		 libgomp_cv_have_attribute_dllexport, [
  save_CFLAGS="$CFLAGS"
  CFLAGS="$CFLAGS -Werror"
  AC_TRY_COMPILE([void __attribute__((dllexport)) foo(void) { }],
		 [], libgomp_cv_have_attribute_dllexport=yes,
		 libgomp_cv_have_attribute_dllexport=no)
  CFLAGS="$save_CFLAGS"])
  if test $libgomp_cv_have_attribute_dllexport = yes; then
    AC_DEFINE(HAVE_ATTRIBUTE_DLLEXPORT, 1,
      [Define to 1 if the target supports __attribute__((dllexport)).])
  fi])

dnl Check whether the target supports symbol aliases.
AC_DEFUN([LIBGOMP_CHECK_ATTRIBUTE_ALIAS], [
  AC_CACHE_CHECK([whether the target supports symbol aliases],
		 libgomp_cv_have_attribute_alias, [
  AC_TRY_LINK([
void foo(void) { }
extern void bar(void) __attribute__((alias("foo")));],
    [bar();], libgomp_cv_have_attribute_alias=yes, libgomp_cv_have_attribute_alias=no)])
  if test $libgomp_cv_have_attribute_alias = yes; then
    AC_DEFINE(HAVE_ATTRIBUTE_ALIAS, 1,
      [Define to 1 if the target supports __attribute__((alias(...))).])
  fi])

sinclude(../libtool.m4)
dnl The lines below arrange for aclocal not to bring an installed
dnl libtool.m4 into aclocal.m4, while still arranging for automake to
dnl add a definition of LIBTOOL to Makefile.in.
ifelse(,,,[AC_SUBST(LIBTOOL)
AC_DEFUN([AM_PROG_LIBTOOL])
AC_DEFUN([AC_LIBTOOL_DLOPEN])
AC_DEFUN([AC_PROG_LD])
])

dnl ----------------------------------------------------------------------
dnl This whole bit snagged from libstdc++-v3.

dnl
dnl LIBGOMP_ENABLE
dnl    (FEATURE, DEFAULT, HELP-ARG, HELP-STRING)
dnl    (FEATURE, DEFAULT, HELP-ARG, HELP-STRING, permit a|b|c)
dnl    (FEATURE, DEFAULT, HELP-ARG, HELP-STRING, SHELL-CODE-HANDLER)
dnl
dnl See docs/html/17_intro/configury.html#enable for documentation.
dnl
m4_define([LIBGOMP_ENABLE],[dnl
m4_define([_g_switch],[--enable-$1])dnl
m4_define([_g_help],[AC_HELP_STRING(_g_switch$3,[$4 @<:@default=$2@:>@])])dnl
 AC_ARG_ENABLE($1,_g_help,
  m4_bmatch([$5],
   [^permit ],
     [[
      case "$enableval" in
       m4_bpatsubst([$5],[permit ])) ;;
       *) AC_MSG_ERROR(Unknown argument to enable/disable $1) ;;
          dnl Idea for future:  generate a URL pointing to
          dnl "onlinedocs/configopts.html#whatever"
      esac
     ]],
   [^$],
     [[
      case "$enableval" in
       yes|no) ;;
       *) AC_MSG_ERROR(Argument to enable/disable $1 must be yes or no) ;;
      esac
     ]],
   [[$5]]),
  [enable_]m4_bpatsubst([$1],-,_)[=][$2])
m4_undefine([_g_switch])dnl
m4_undefine([_g_help])dnl
])


dnl
dnl If GNU ld is in use, check to see if tricky linker opts can be used.  If
dnl the native linker is in use, all variables will be defined to something
dnl safe (like an empty string).
dnl
dnl Defines:
dnl  SECTION_LDFLAGS='-Wl,--gc-sections' if possible
dnl  OPT_LDFLAGS='-Wl,-O1' if possible
dnl  LD (as a side effect of testing)
dnl Sets:
dnl  with_gnu_ld
dnl  libgomp_ld_is_gold (possibly)
dnl  libgomp_gnu_ld_version (possibly)
dnl
dnl The last will be a single integer, e.g., version 1.23.45.0.67.89 will
dnl set libgomp_gnu_ld_version to 12345.  Zeros cause problems.
dnl
AC_DEFUN([LIBGOMP_CHECK_LINKER_FEATURES], [
  # If we're not using GNU ld, then there's no point in even trying these
  # tests.  Check for that first.  We should have already tested for gld
  # by now (in libtool), but require it now just to be safe...
  test -z "$SECTION_LDFLAGS" && SECTION_LDFLAGS=''
  test -z "$OPT_LDFLAGS" && OPT_LDFLAGS=''
  AC_REQUIRE([AC_PROG_LD])
  AC_REQUIRE([AC_PROG_AWK])

  # The name set by libtool depends on the version of libtool.  Shame on us
  # for depending on an impl detail, but c'est la vie.  Older versions used
  # ac_cv_prog_gnu_ld, but now it's lt_cv_prog_gnu_ld, and is copied back on
  # top of with_gnu_ld (which is also set by --with-gnu-ld, so that actually
  # makes sense).  We'll test with_gnu_ld everywhere else, so if that isn't
  # set (hence we're using an older libtool), then set it.
  if test x${with_gnu_ld+set} != xset; then
    if test x${ac_cv_prog_gnu_ld+set} != xset; then
      # We got through "ac_require(ac_prog_ld)" and still not set?  Huh?
      with_gnu_ld=no
    else
      with_gnu_ld=$ac_cv_prog_gnu_ld
    fi
  fi

  # Start by getting the version number.  I think the libtool test already
  # does some of this, but throws away the result.
  libgomp_ld_is_gold=no
  if $LD --version 2>/dev/null | grep 'GNU gold'> /dev/null 2>&1; then
    libgomp_ld_is_gold=yes
  fi
  changequote(,)
  ldver=`$LD --version 2>/dev/null |
         sed -e 's/GNU gold /GNU ld /;s/GNU ld version /GNU ld /;s/GNU ld ([^)]*) /GNU ld /;s/GNU ld \([0-9.][0-9.]*\).*/\1/; q'`
  changequote([,])
  libgomp_gnu_ld_version=`echo $ldver | \
         $AWK -F. '{ if (NF<3) [$]3=0; print ([$]1*100+[$]2)*100+[$]3 }'`

  # Set --gc-sections.
  if test "$with_gnu_ld" = "notbroken"; then
    # GNU ld it is!  Joy and bunny rabbits!

    # All these tests are for C++; save the language and the compiler flags.
    # Need to do this so that g++ won't try to link in libstdc++
    ac_test_CFLAGS="${CFLAGS+set}"
    ac_save_CFLAGS="$CFLAGS"
    CFLAGS='-x c++  -Wl,--gc-sections'

    # Check for -Wl,--gc-sections
    # XXX This test is broken at the moment, as symbols required for linking
    # are now in libsupc++ (not built yet).  In addition, this test has
    # cored on solaris in the past.  In addition, --gc-sections doesn't
    # really work at the moment (keeps on discarding used sections, first
    # .eh_frame and now some of the glibc sections for iconv).
    # Bzzzzt.  Thanks for playing, maybe next time.
    AC_MSG_CHECKING([for ld that supports -Wl,--gc-sections])
    AC_TRY_RUN([
     int main(void)
     {
       try { throw 1; }
       catch (...) { };
       return 0;
     }
    ], [ac_sectionLDflags=yes],[ac_sectionLDflags=no], [ac_sectionLDflags=yes])
    if test "$ac_test_CFLAGS" = set; then
      CFLAGS="$ac_save_CFLAGS"
    else
      # this is the suspicious part
      CFLAGS=''
    fi
    if test "$ac_sectionLDflags" = "yes"; then
      SECTION_LDFLAGS="-Wl,--gc-sections $SECTION_LDFLAGS"
    fi
    AC_MSG_RESULT($ac_sectionLDflags)
  fi

  # Set linker optimization flags.
  if test x"$with_gnu_ld" = x"yes"; then
    OPT_LDFLAGS="-Wl,-O1 $OPT_LDFLAGS"
  fi

  AC_SUBST(SECTION_LDFLAGS)
  AC_SUBST(OPT_LDFLAGS)
])


dnl
dnl Add version tags to symbols in shared library (or not), additionally
dnl marking other symbols as private/local (or not).
dnl
dnl --enable-symvers=style adds a version script to the linker call when
dnl       creating the shared library.  The choice of version script is
dnl       controlled by 'style'.
dnl --disable-symvers does not.
dnl  +  Usage:  LIBGOMP_ENABLE_SYMVERS[(DEFAULT)]
dnl       Where DEFAULT is either 'yes' or 'no'.  Passing `yes' tries to
dnl       choose a default style based on linker characteristics.  Passing
dnl       'no' disables versioning.
dnl
AC_DEFUN([LIBGOMP_ENABLE_SYMVERS], [

LIBGOMP_ENABLE(symvers,yes,[=STYLE],
  [enables symbol versioning of the shared library],
  [permit yes|no|gnu])

# If we never went through the LIBGOMP_CHECK_LINKER_FEATURES macro, then we
# don't know enough about $LD to do tricks...
AC_REQUIRE([LIBGOMP_CHECK_LINKER_FEATURES])
# FIXME  The following test is too strict, in theory.
if test $enable_shared = no ||
        test "x$LD" = x ||
        test x$libgomp_gnu_ld_version = x; then
  enable_symvers=no
fi

# Check to see if libgcc_s exists, indicating that shared libgcc is possible.
if test $enable_symvers != no; then
  AC_MSG_CHECKING([for shared libgcc])
  ac_save_CFLAGS="$CFLAGS"
  CFLAGS=' -lgcc_s'
  AC_TRY_LINK(, [return 0;], libgomp_shared_libgcc=yes, libgomp_shared_libgcc=no)
  CFLAGS="$ac_save_CFLAGS"
  if test $libgomp_shared_libgcc = no; then
    cat > conftest.c <<EOF
int main (void) { return 0; }
EOF
changequote(,)dnl
    libgomp_libgcc_s_suffix=`${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS \
			     -shared -shared-libgcc -o conftest.so \
			     conftest.c -v 2>&1 >/dev/null \
			     | sed -n 's/^.* -lgcc_s\([^ ]*\) .*$/\1/p'`
changequote([,])dnl
    rm -f conftest.c conftest.so
    if test x${libgomp_libgcc_s_suffix+set} = xset; then
      CFLAGS=" -lgcc_s$libgomp_libgcc_s_suffix"
      AC_TRY_LINK(, [return 0;], libgomp_shared_libgcc=yes)
      CFLAGS="$ac_save_CFLAGS"
    fi
  fi
  AC_MSG_RESULT($libgomp_shared_libgcc)
fi

# For GNU ld, we need at least this version.  The format is described in
# LIBGOMP_CHECK_LINKER_FEATURES above.
libgomp_min_gnu_ld_version=21400
# XXXXXXXXXXX libgomp_gnu_ld_version=21390

# Check to see if unspecified "yes" value can win, given results above.
# Change "yes" into either "no" or a style name.
if test $enable_symvers = yes; then
  if test $with_gnu_ld = yes &&
     test $libgomp_shared_libgcc = yes;
  then
    if test $libgomp_gnu_ld_version -ge $libgomp_min_gnu_ld_version ; then
      enable_symvers=gnu
    elif test $libgomp_ld_is_gold = yes ; then
      enable_symvers=gnu
    else
      # The right tools, the right setup, but too old.  Fallbacks?
      AC_MSG_WARN(=== Linker version $libgomp_gnu_ld_version is too old for)
      AC_MSG_WARN(=== full symbol versioning support in this release of GCC.)
      AC_MSG_WARN(=== You would need to upgrade your binutils to version)
      AC_MSG_WARN(=== $libgomp_min_gnu_ld_version or later and rebuild GCC.)
      if test $libgomp_gnu_ld_version -ge 21200 ; then
        # Globbing fix is present, proper block support is not.
        dnl AC_MSG_WARN([=== Dude, you are soooo close.  Maybe we can fake it.])
        dnl enable_symvers=???
        AC_MSG_WARN([=== Symbol versioning will be disabled.])
        enable_symvers=no
      else
        # 2.11 or older.
        AC_MSG_WARN([=== Symbol versioning will be disabled.])
        enable_symvers=no
      fi
    fi
  else
    # just fail for now
    AC_MSG_WARN([=== You have requested some kind of symbol versioning, but])
    AC_MSG_WARN([=== either you are not using a supported linker, or you are])
    AC_MSG_WARN([=== not building a shared libgcc_s (which is required).])
    AC_MSG_WARN([=== Symbol versioning will be disabled.])
    enable_symvers=no
  fi
fi

AC_CACHE_CHECK([whether the target supports .symver directive],
	       libgomp_cv_have_as_symver_directive, [
  AC_TRY_COMPILE([void foo (void); __asm (".symver foo, bar@SYMVER");],
		 [], libgomp_cv_have_as_symver_directive=yes,
		 libgomp_cv_have_as_symver_directive=no)])
if test $libgomp_cv_have_as_symver_directive = yes; then
  AC_DEFINE(HAVE_AS_SYMVER_DIRECTIVE, 1,
    [Define to 1 if the target assembler supports .symver directive.])
fi

AM_CONDITIONAL(LIBGOMP_BUILD_VERSIONED_SHLIB, test $enable_symvers != no)
AC_MSG_NOTICE(versioning on shared library symbols is $enable_symvers)
])
Commit	Line	Data
1e8e9920	1	dnl ----------------------------------------------------------------------
	2	dnl This whole bit snagged from libgfortran.
	3
	4	dnl Check whether the target supports __sync_*_compare_and_swap.
	5	AC_DEFUN([LIBGOMP_CHECK_SYNC_BUILTINS], [
	6	AC_CACHE_CHECK([whether the target supports __sync_*_compare_and_swap],
6992582a	7	libgomp_cv_have_sync_builtins, [
14a88549	8	AC_TRY_LINK([], [int foo; __sync_val_compare_and_swap(&foo, 0, 1);],
6992582a	9	libgomp_cv_have_sync_builtins=yes, libgomp_cv_have_sync_builtins=no)])
6992582a	10	if test $libgomp_cv_have_sync_builtins = yes; then
1e8e9920	11	AC_DEFINE(HAVE_SYNC_BUILTINS, 1,
	12	[Define to 1 if the target supports __sync_*_compare_and_swap])
	13	fi])
	14
	15	dnl Check whether the target supports hidden visibility.
	16	AC_DEFUN([LIBGOMP_CHECK_ATTRIBUTE_VISIBILITY], [
	17	AC_CACHE_CHECK([whether the target supports hidden visibility],
6992582a	18	libgomp_cv_have_attribute_visibility, [
1e8e9920	19	save_CFLAGS="$CFLAGS"
	20	CFLAGS="$CFLAGS -Werror"
	21	AC_TRY_COMPILE([void __attribute__((visibility("hidden"))) foo(void) { }],
6992582a	22	[], libgomp_cv_have_attribute_visibility=yes,
6992582a	23	libgomp_cv_have_attribute_visibility=no)
1e8e9920	24	CFLAGS="$save_CFLAGS"])
6992582a	25	if test $libgomp_cv_have_attribute_visibility = yes; then
1e8e9920	26	AC_DEFINE(HAVE_ATTRIBUTE_VISIBILITY, 1,
	27	[Define to 1 if the target supports __attribute__((visibility(...))).])
	28	fi])
	29
	30	dnl Check whether the target supports dllexport
	31	AC_DEFUN([LIBGOMP_CHECK_ATTRIBUTE_DLLEXPORT], [
	32	AC_CACHE_CHECK([whether the target supports dllexport],
6992582a	33	libgomp_cv_have_attribute_dllexport, [
1e8e9920	34	save_CFLAGS="$CFLAGS"
	35	CFLAGS="$CFLAGS -Werror"
	36	AC_TRY_COMPILE([void __attribute__((dllexport)) foo(void) { }],
6992582a	37	[], libgomp_cv_have_attribute_dllexport=yes,
6992582a	38	libgomp_cv_have_attribute_dllexport=no)
1e8e9920	39	CFLAGS="$save_CFLAGS"])
6992582a	40	if test $libgomp_cv_have_attribute_dllexport = yes; then
1e8e9920	41	AC_DEFINE(HAVE_ATTRIBUTE_DLLEXPORT, 1,
	42	[Define to 1 if the target supports __attribute__((dllexport)).])
	43	fi])
	44
	45	dnl Check whether the target supports symbol aliases.
	46	AC_DEFUN([LIBGOMP_CHECK_ATTRIBUTE_ALIAS], [
	47	AC_CACHE_CHECK([whether the target supports symbol aliases],
6992582a	48	libgomp_cv_have_attribute_alias, [
1e8e9920	49	AC_TRY_LINK([
1e8e9920	50	void foo(void) { }
c812091b	51	extern void bar(void) __attribute__((alias("foo")));],
6992582a	52	[bar();], libgomp_cv_have_attribute_alias=yes, libgomp_cv_have_attribute_alias=no)])
6992582a	53	if test $libgomp_cv_have_attribute_alias = yes; then
1e8e9920	54	AC_DEFINE(HAVE_ATTRIBUTE_ALIAS, 1,
	55	[Define to 1 if the target supports __attribute__((alias(...))).])
	56	fi])
	57
	58	sinclude(../libtool.m4)
	59	dnl The lines below arrange for aclocal not to bring an installed
	60	dnl libtool.m4 into aclocal.m4, while still arranging for automake to
	61	dnl add a definition of LIBTOOL to Makefile.in.
	62	ifelse(,,,[AC_SUBST(LIBTOOL)
	63	AC_DEFUN([AM_PROG_LIBTOOL])
	64	AC_DEFUN([AC_LIBTOOL_DLOPEN])
	65	AC_DEFUN([AC_PROG_LD])
	66	])
	67
	68	dnl ----------------------------------------------------------------------
	69	dnl This whole bit snagged from libstdc++-v3.
	70
	71	dnl
	72	dnl LIBGOMP_ENABLE
	73	dnl (FEATURE, DEFAULT, HELP-ARG, HELP-STRING)
	74	dnl (FEATURE, DEFAULT, HELP-ARG, HELP-STRING, permit a\|b\|c)
	75	dnl (FEATURE, DEFAULT, HELP-ARG, HELP-STRING, SHELL-CODE-HANDLER)
	76	dnl
	77	dnl See docs/html/17_intro/configury.html#enable for documentation.
	78	dnl
	79	m4_define([LIBGOMP_ENABLE],[dnl
	80	m4_define([_g_switch],[--enable-$1])dnl
	81	m4_define([_g_help],[AC_HELP_STRING(_g_switch$3,[$4 @<:@default=$2@:>@])])dnl
	82	AC_ARG_ENABLE($1,_g_help,
	83	m4_bmatch([$5],
	84	[^permit ],
	85	[[
	86	case "$enableval" in
	87	m4_bpatsubst([$5],[permit ])) ;;
	88	*) AC_MSG_ERROR(Unknown argument to enable/disable $1) ;;
	89	dnl Idea for future: generate a URL pointing to
	90	dnl "onlinedocs/configopts.html#whatever"
	91	esac
	92	]],
	93	[^$],
	94	[[
	95	case "$enableval" in
	96	yes\|no) ;;
	97	*) AC_MSG_ERROR(Argument to enable/disable $1 must be yes or no) ;;
	98	esac
	99	]],
	100	[[$5]]),
	101	[enable_]m4_bpatsubst([$1],-,_)[=][$2])
	102	m4_undefine([_g_switch])dnl
	103	m4_undefine([_g_help])dnl
	104	])
	105
	106
	107	dnl
	108	dnl If GNU ld is in use, check to see if tricky linker opts can be used. If
	109	dnl the native linker is in use, all variables will be defined to something
	110	dnl safe (like an empty string).
	111	dnl
	112	dnl Defines:
	113	dnl SECTION_LDFLAGS='-Wl,--gc-sections' if possible
	114	dnl OPT_LDFLAGS='-Wl,-O1' if possible
	115	dnl LD (as a side effect of testing)
	116	dnl Sets:
	117	dnl with_gnu_ld
d3d87030	118	dnl libgomp_ld_is_gold (possibly)
1e8e9920	119	dnl libgomp_gnu_ld_version (possibly)
	120	dnl
	121	dnl The last will be a single integer, e.g., version 1.23.45.0.67.89 will
	122	dnl set libgomp_gnu_ld_version to 12345. Zeros cause problems.
	123	dnl
	124	AC_DEFUN([LIBGOMP_CHECK_LINKER_FEATURES], [
	125	# If we're not using GNU ld, then there's no point in even trying these
	126	# tests. Check for that first. We should have already tested for gld
	127	# by now (in libtool), but require it now just to be safe...
	128	test -z "$SECTION_LDFLAGS" && SECTION_LDFLAGS=''
	129	test -z "$OPT_LDFLAGS" && OPT_LDFLAGS=''
	130	AC_REQUIRE([AC_PROG_LD])
	131	AC_REQUIRE([AC_PROG_AWK])
	132
	133	# The name set by libtool depends on the version of libtool. Shame on us
	134	# for depending on an impl detail, but c'est la vie. Older versions used
	135	# ac_cv_prog_gnu_ld, but now it's lt_cv_prog_gnu_ld, and is copied back on
	136	# top of with_gnu_ld (which is also set by --with-gnu-ld, so that actually
	137	# makes sense). We'll test with_gnu_ld everywhere else, so if that isn't
	138	# set (hence we're using an older libtool), then set it.
	139	if test x${with_gnu_ld+set} != xset; then
	140	if test x${ac_cv_prog_gnu_ld+set} != xset; then
	141	# We got through "ac_require(ac_prog_ld)" and still not set? Huh?
	142	with_gnu_ld=no
	143	else
	144	with_gnu_ld=$ac_cv_prog_gnu_ld
	145	fi
	146	fi
	147
	148	# Start by getting the version number. I think the libtool test already
	149	# does some of this, but throws away the result.
d3d87030	150	libgomp_ld_is_gold=no
	151	if $LD --version 2>/dev/null \| grep 'GNU gold'> /dev/null 2>&1; then
	152	libgomp_ld_is_gold=yes
	153	fi
1e8e9920	154	changequote(,)
8dc52806	155	ldver=`$LD --version 2>/dev/null \|
8b501d36	156	sed -e 's/GNU gold /GNU ld /;s/GNU ld version /GNU ld /;s/GNU ld ([^)]) /GNU ld /;s/GNU ld \([0-9.][0-9.]\).*/\1/; q'`
1e8e9920	157	changequote([,])
	158	libgomp_gnu_ld_version=`echo $ldver \| \
	159	$AWK -F. '{ if (NF<3) [$]3=0; print ([$]1100+[$]2)100+[$]3 }'`
	160
	161	# Set --gc-sections.
	162	if test "$with_gnu_ld" = "notbroken"; then
	163	# GNU ld it is! Joy and bunny rabbits!
	164
	165	# All these tests are for C++; save the language and the compiler flags.
	166	# Need to do this so that g++ won't try to link in libstdc++
	167	ac_test_CFLAGS="${CFLAGS+set}"
	168	ac_save_CFLAGS="$CFLAGS"
	169	CFLAGS='-x c++ -Wl,--gc-sections'
	170
	171	# Check for -Wl,--gc-sections
	172	# XXX This test is broken at the moment, as symbols required for linking
	173	# are now in libsupc++ (not built yet). In addition, this test has
	174	# cored on solaris in the past. In addition, --gc-sections doesn't
	175	# really work at the moment (keeps on discarding used sections, first
	176	# .eh_frame and now some of the glibc sections for iconv).
	177	# Bzzzzt. Thanks for playing, maybe next time.
	178	AC_MSG_CHECKING([for ld that supports -Wl,--gc-sections])
	179	AC_TRY_RUN([
	180	int main(void)
	181	{
	182	try { throw 1; }
	183	catch (...) { };
	184	return 0;
	185	}
	186	], [ac_sectionLDflags=yes],[ac_sectionLDflags=no], [ac_sectionLDflags=yes])
	187	if test "$ac_test_CFLAGS" = set; then
	188	CFLAGS="$ac_save_CFLAGS"
	189	else
	190	# this is the suspicious part
	191	CFLAGS=''
	192	fi
	193	if test "$ac_sectionLDflags" = "yes"; then
	194	SECTION_LDFLAGS="-Wl,--gc-sections $SECTION_LDFLAGS"
	195	fi
	196	AC_MSG_RESULT($ac_sectionLDflags)
	197	fi
	198
	199	# Set linker optimization flags.
	200	if test x"$with_gnu_ld" = x"yes"; then
	201	OPT_LDFLAGS="-Wl,-O1 $OPT_LDFLAGS"
	202	fi
	203
	204	AC_SUBST(SECTION_LDFLAGS)
	205	AC_SUBST(OPT_LDFLAGS)
	206	])
	207
	208
	209	dnl
	210	dnl Add version tags to symbols in shared library (or not), additionally
	211	dnl marking other symbols as private/local (or not).
	212	dnl
	213	dnl --enable-symvers=style adds a version script to the linker call when
	214	dnl creating the shared library. The choice of version script is
	215	dnl controlled by 'style'.
	216	dnl --disable-symvers does not.
	217	dnl + Usage: LIBGOMP_ENABLE_SYMVERS[(DEFAULT)]
	218	dnl Where DEFAULT is either 'yes' or 'no'. Passing `yes' tries to
	219	dnl choose a default style based on linker characteristics. Passing
	220	dnl 'no' disables versioning.
221	dnl
222	AC_DEFUN([LIBGOMP_ENABLE_SYMVERS], [
223
224	LIBGOMP_ENABLE(symvers,yes,[=STYLE],
225	[enables symbol versioning of the shared library],
226	[permit yes\|no\|gnu])
227
228	# If we never went through the LIBGOMP_CHECK_LINKER_FEATURES macro, then we
229	# don't know enough about $LD to do tricks...
230	AC_REQUIRE([LIBGOMP_CHECK_LINKER_FEATURES])
231	# FIXME The following test is too strict, in theory.
232	if test $enable_shared = no \|\|
233	test "x$LD" = x \|\|
234	test x$libgomp_gnu_ld_version = x; then
235	enable_symvers=no
236	fi
237
238	# Check to see if libgcc_s exists, indicating that shared libgcc is possible.
239	if test $enable_symvers != no; then
240	AC_MSG_CHECKING([for shared libgcc])
241	ac_save_CFLAGS="$CFLAGS"
242	CFLAGS=' -lgcc_s'
243	AC_TRY_LINK(, [return 0;], libgomp_shared_libgcc=yes, libgomp_shared_libgcc=no)
244	CFLAGS="$ac_save_CFLAGS"
245	if test $libgomp_shared_libgcc = no; then
246	cat > conftest.c <<EOF
247	int main (void) { return 0; }
248	EOF
249	changequote(,)dnl
250	libgomp_libgcc_s_suffix=`${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS \
251	-shared -shared-libgcc -o conftest.so \
252	conftest.c -v 2>&1 >/dev/null \
253	\| sed -n 's/^.* -lgcc_s\([^ ]\) .$/\1/p'`
254	changequote([,])dnl
255	rm -f conftest.c conftest.so
256	if test x${libgomp_libgcc_s_suffix+set} = xset; then
257	CFLAGS=" -lgcc_s$libgomp_libgcc_s_suffix"
258	AC_TRY_LINK(, [return 0;], libgomp_shared_libgcc=yes)
259	CFLAGS="$ac_save_CFLAGS"
260	fi
261	fi
262	AC_MSG_RESULT($libgomp_shared_libgcc)
263	fi
264
265	# For GNU ld, we need at least this version. The format is described in
266	# LIBGOMP_CHECK_LINKER_FEATURES above.
267	libgomp_min_gnu_ld_version=21400
268	# XXXXXXXXXXX libgomp_gnu_ld_version=21390
269
270	# Check to see if unspecified "yes" value can win, given results above.
271	# Change "yes" into either "no" or a style name.
272	if test $enable_symvers = yes; then
273	if test $with_gnu_ld = yes &&
274	test $libgomp_shared_libgcc = yes;
275	then
276	if test $libgomp_gnu_ld_version -ge $libgomp_min_gnu_ld_version ; then
277	enable_symvers=gnu
d3d87030	278	elif test $libgomp_ld_is_gold = yes ; then
d3d87030	279	enable_symvers=gnu
1e8e9920	280	else
	281	# The right tools, the right setup, but too old. Fallbacks?
	282	AC_MSG_WARN(=== Linker version $libgomp_gnu_ld_version is too old for)
	283	AC_MSG_WARN(=== full symbol versioning support in this release of GCC.)
	284	AC_MSG_WARN(=== You would need to upgrade your binutils to version)
	285	AC_MSG_WARN(=== $libgomp_min_gnu_ld_version or later and rebuild GCC.)
	286	if test $libgomp_gnu_ld_version -ge 21200 ; then
	287	# Globbing fix is present, proper block support is not.
	288	dnl AC_MSG_WARN([=== Dude, you are soooo close. Maybe we can fake it.])
	289	dnl enable_symvers=???
	290	AC_MSG_WARN([=== Symbol versioning will be disabled.])
	291	enable_symvers=no
	292	else
	293	# 2.11 or older.
	294	AC_MSG_WARN([=== Symbol versioning will be disabled.])
	295	enable_symvers=no
	296	fi
	297	fi
	298	else
	299	# just fail for now
	300	AC_MSG_WARN([=== You have requested some kind of symbol versioning, but])
	301	AC_MSG_WARN([=== either you are not using a supported linker, or you are])
	302	AC_MSG_WARN([=== not building a shared libgcc_s (which is required).])
	303	AC_MSG_WARN([=== Symbol versioning will be disabled.])
	304	enable_symvers=no
	305	fi
	306	fi
	307
8a75144c	308	AC_CACHE_CHECK([whether the target supports .symver directive],
	309	libgomp_cv_have_as_symver_directive, [
	310	AC_TRY_COMPILE([void foo (void); __asm (".symver foo, bar@SYMVER");],
	311	[], libgomp_cv_have_as_symver_directive=yes,
	312	libgomp_cv_have_as_symver_directive=no)])
	313	if test $libgomp_cv_have_as_symver_directive = yes; then
	314	AC_DEFINE(HAVE_AS_SYMVER_DIRECTIVE, 1,
	315	[Define to 1 if the target assembler supports .symver directive.])
	316	fi
	317
1e8e9920	318	AM_CONDITIONAL(LIBGOMP_BUILD_VERSIONED_SHLIB, test $enable_symvers != no)
	319	AC_MSG_NOTICE(versioning on shared library symbols is $enable_symvers)
	320	])