diff options
Diffstat (limited to 'config/tls.m4')
| -rw-r--r-- | config/tls.m4 | 20 |
1 files changed, 19 insertions, 1 deletions
diff --git a/config/tls.m4 b/config/tls.m4 index acb123f69..0ae60460b 100644 --- a/config/tls.m4 +++ b/config/tls.m4 @@ -1,5 +1,6 @@ dnl Check whether the target supports TLS. AC_DEFUN([GCC_CHECK_TLS], [ + AC_REQUIRE([AC_CANONICAL_HOST]) GCC_ENABLE(tls, yes, [], [Use thread-local storage]) AC_CACHE_CHECK([whether the target supports thread-local storage], gcc_cv_have_tls, [ @@ -66,7 +67,24 @@ AC_DEFUN([GCC_CHECK_TLS], [ [dnl This is the cross-compiling case. Assume libc supports TLS if the dnl binutils and the compiler do. AC_LINK_IFELSE([__thread int a; int b; int main() { return a = b; }], - [gcc_cv_have_tls=yes], [gcc_cv_have_tls=no]) + [chktls_save_LDFLAGS="$LDFLAGS" + dnl Shared library options may depend on the host; this check + dnl is only known to be needed for GNU/Linux. + case $host in + *-*-linux*) + LDFLAGS="-shared -Wl,--no-undefined $LDFLAGS" + ;; + esac + chktls_save_CFLAGS="$CFLAGS" + CFLAGS="-fPIC $CFLAGS" + dnl If -shared works, test if TLS works in a shared library. + AC_LINK_IFELSE([int f() { return 0; }], + [AC_LINK_IFELSE([__thread int a; int b; int f() { return a = b; }], + [gcc_cv_have_tls=yes], + [gcc_cv_have_tls=no])], + [gcc_cv_have_tls=yes]) + CFLAGS="$chktls_save_CFLAGS" + LDFLAGS="$chktls_save_LDFLAGS"], [gcc_cv_have_tls=no]) ] )]) if test "$enable_tls $gcc_cv_have_tls" = "yes yes"; then |