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-rw-r--r--config/ChangeLog5
-rw-r--r--config/tls.m420
2 files changed, 24 insertions, 1 deletions
diff --git a/config/ChangeLog b/config/ChangeLog
index d6ff565..9b8cd93 100644
--- a/config/ChangeLog
+++ b/config/ChangeLog
@@ -1,3 +1,8 @@
+2009-07-16 Joseph Myers <joseph@codesourcery.com>
+
+ * tls.m4 (GCC_CHECK_TLS): Also test TLS in a shared library when
+ cross-compiling.
+
2009-05-26 Rafael Avila de Espindola <espindola@google.com>
* plugins.m4: New.
diff --git a/config/tls.m4 b/config/tls.m4
index acb123f..4648a90 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