diff options
Diffstat (limited to 'libstdc++-v3/acinclude.m4')
| -rw-r--r-- | libstdc++-v3/acinclude.m4 | 67 |
1 files changed, 44 insertions, 23 deletions
diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4 index d4ddc494258..db63087d423 100644 --- a/libstdc++-v3/acinclude.m4 +++ b/libstdc++-v3/acinclude.m4 @@ -187,7 +187,7 @@ 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 OPT_LDFLAGS='-Wl,-O1' and '-z,relro' if possible dnl LD (as a side effect of testing) dnl Sets: dnl with_gnu_ld @@ -222,49 +222,70 @@ AC_DEFUN([GLIBCXX_CHECK_LINKER_FEATURES], [ # Start by getting the version number. I think the libtool test already # does some of this, but throws away the result. + AC_MSG_CHECKING([for ld version]) changequote(,) ldver=`$LD --version 2>/dev/null | head -1 | \ sed -e 's/GNU ld version \([0-9.][0-9.]*\).*/\1/'` changequote([,]) glibcxx_gnu_ld_version=`echo $ldver | \ $AWK -F. '{ if (NF<3) [$]3=0; print ([$]1*100+[$]2)*100+[$]3 }'` + AC_MSG_RESULT($glibcxx_gnu_ld_version) # Set --gc-sections. - if test "$with_gnu_ld" = "notbroken"; then - # GNU ld it is! Joy and bunny rabbits! + glibcxx_gcsections_min_ld=21602 + if test x"$with_gnu_ld" = x"yes" && + test $glibcxx_gnu_ld_version -gt $glibcxx_gcsections_min_ld ; then - # All these tests are for C++; save the language and the compiler flags. - # Need to do this so that g++ won't try to link in libstdc++ + # Sufficiently young GNU ld it is! Joy and bunny rabbits! + # NB: This flag only works reliably after 2.16.1. Configure tests + # for this are difficult, so hard wire a value that should work. + + # All these tests are for C++, but run with the "C" compiler driver. + # Need to do this so that g++ won't try to link in libstdc++/libsupc++. ac_test_CFLAGS="${CFLAGS+set}" ac_save_CFLAGS="$CFLAGS" - CFLAGS='-x c++ -Wl,--gc-sections' + CFLAGS='-x c++ -Wl,--gc-sections' # Check for -Wl,--gc-sections - # XXX This test is broken at the moment, as symbols required for linking - # are now in libsupc++ (not built yet). In addition, this test has - # cored on solaris in the past. In addition, --gc-sections doesn't - # really work at the moment (keeps on discarding used sections, first - # .eh_frame and now some of the glibc sections for iconv). - # Bzzzzt. Thanks for playing, maybe next time. AC_MSG_CHECKING([for ld that supports -Wl,--gc-sections]) - AC_TRY_RUN([ - int main(void) - { - try { throw 1; } - catch (...) { }; - return 0; - } - ], [ac_sectionLDflags=yes],[ac_sectionLDflags=no], [ac_sectionLDflags=yes]) + AC_TRY_LINK([ int one(void) { return 1; } + int two(void) { return 2; } + ], [ two(); ] , [ac_gcsections=yes], [ac_gcsections=no]) + if test "$ac_gcsections" = "yes"; then + rm -f conftest.c + touch conftest.c + if $CC -c conftest.c; then + if $LD --gc-sections -o conftest conftest.o 2>&1 | \ + grep "Warning: gc-sections option ignored" > /dev/null; then + ac_gcsections=no + fi + fi + rm -f conftest.c conftest.o conftest + fi + if test "$ac_gcsections" = "yes"; then + SECTION_LDFLAGS="-Wl,--gc-sections $SECTION_LDFLAGS" + fi + AC_MSG_RESULT($ac_gcsections) + 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 $SECTION_LDFLAGS" + fi + + # Set -z,relro. + # Note this is only for shared objects. + ac_ld_relro=no + if test x"$with_gnu_ld" = x"yes"; then + AC_MSG_CHECKING([for ld that supports -Wl,-z,relro]) + cxx_z_relo=`$LD -v --help 2>/dev/null | grep "z relro"` + if test -n "$cxx_z_relo"; then + OPT_LDFLAGS="-Wl,-z,relro" + ac_ld_relro=yes fi - AC_MSG_RESULT($ac_sectionLDflags) + AC_MSG_RESULT($ac_ld_relro) fi # Set linker optimization flags. |