| dnl Check whether the target supports TLS. |
| AC_DEFUN([GCC_CHECK_TLS], [ |
| GCC_ENABLE(tls, yes, [Use thread-local storage]) |
| AC_CACHE_CHECK([whether the target supports thread-local storage], |
| have_tls, [ |
| AC_RUN_IFELSE([__thread int a; int b; int main() { return a = b; }], |
| [dnl If the test case passed with dynamic linking, try again with |
| dnl static linking. This fails at least with some older Red Hat |
| dnl releases. |
| save_LDFLAGS="$LDFLAGS" |
| LDFLAGS="-static $LDFLAGS" |
| AC_RUN_IFELSE([__thread int a; int b; int main() { return a = b; }], |
| [have_tls=yes], [have_tls=no], []) |
| LDFLAGS="$save_LDFLAGS"], |
| [have_tls=no], |
| [AC_COMPILE_IFELSE([__thread int foo;], [have_tls=yes], [have_tls=no])] |
| )]) |
| if test "$enable_tls $have_tls" = "yes yes"; then |
| AC_DEFINE(HAVE_TLS, 1, |
| [Define to 1 if the target supports thread-local storage.]) |
| fi]) |
