dnl Check whether the target supports TLS.
AC_DEFUN([GCC_CHECK_TLS], [
- GCC_ENABLE(tls, yes, [Use thread-local storage])
+ AC_REQUIRE([AC_CANONICAL_HOST])
+ GCC_ENABLE(tls, yes, [], [Use thread-local storage])
AC_CACHE_CHECK([whether the target supports thread-local storage],
- have_tls, [
+ gcc_cv_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="$LDFLAGS"
+ dnl static linking, but only if static linking is supported (not
+ dnl on Solaris 10). This fails with some older Red Hat releases.
+ chktls_save_LDFLAGS="$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])]
+ AC_LINK_IFELSE([int main() { return 0; }],
+ [AC_RUN_IFELSE([__thread int a; int b; int main() { return a = b; }],
+ [gcc_cv_have_tls=yes], [gcc_cv_have_tls=no],[])],
+ [gcc_cv_have_tls=yes])
+ LDFLAGS="$chktls_save_LDFLAGS"
+ if test $gcc_cv_have_tls = yes; then
+ dnl So far, the binutils and the compiler support TLS.
+ dnl Also check whether the libc supports TLS, i.e. whether a variable
+ dnl with __thread linkage has a different address in different threads.
+ dnl First, find the thread_CFLAGS necessary for linking a program that
+ dnl calls pthread_create.
+ chktls_save_CFLAGS="$CFLAGS"
+ thread_CFLAGS=failed
+ for flag in '' '-pthread' '-lpthread'; do
+ CFLAGS="$flag $chktls_save_CFLAGS"
+ AC_LINK_IFELSE(
+ [AC_LANG_PROGRAM(
+ [#include <pthread.h>
+ void *g(void *d) { return NULL; }],
+ [pthread_t t; pthread_create(&t,NULL,g,NULL);])],
+ [thread_CFLAGS="$flag"])
+ if test "X$thread_CFLAGS" != Xfailed; then
+ break
+ fi
+ done
+ CFLAGS="$chktls_save_CFLAGS"
+ if test "X$thread_CFLAGS" != Xfailed; then
+ CFLAGS="$thread_CFLAGS $chktls_save_CFLAGS"
+ AC_RUN_IFELSE(
+ [AC_LANG_PROGRAM(
+ [#include <pthread.h>
+ __thread int a;
+ static int *a_in_other_thread;
+ static void *
+ thread_func (void *arg)
+ {
+ a_in_other_thread = &a;
+ return (void *)0;
+ }],
+ [pthread_t thread;
+ void *thread_retval;
+ int *a_in_main_thread;
+ if (pthread_create (&thread, (pthread_attr_t *)0,
+ thread_func, (void *)0))
+ return 0;
+ a_in_main_thread = &a;
+ if (pthread_join (thread, &thread_retval))
+ return 0;
+ return (a_in_other_thread == a_in_main_thread);])],
+ [gcc_cv_have_tls=yes], [gcc_cv_have_tls=no], [])
+ CFLAGS="$chktls_save_CFLAGS"
+ fi
+ fi],
+ [gcc_cv_have_tls=no],
+ [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; }],
+ [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 $have_tls" = "yes yes"; then
+ if test "$enable_tls $gcc_cv_have_tls" = "yes yes"; then
AC_DEFINE(HAVE_TLS, 1,
[Define to 1 if the target supports thread-local storage.])
fi])
+
+dnl Check whether the target assembler supports TLS.
+AC_DEFUN([GCC_CHECK_CC_TLS], [
+ GCC_ENABLE(tls, yes, [], [Use thread-local storage])
+ AC_CACHE_CHECK([whether the target assembler supports thread-local storage],
+ gcc_cv_have_cc_tls, [
+ AC_COMPILE_IFELSE([__thread int a; int b; int main() { return a = b; }],
+ [gcc_cv_have_cc_tls=yes], [gcc_cv_have_cc_tls=no])]
+ )])
+ if test "$enable_tls $gcc_cv_have_cc_tls" = "yes yes"; then
+ AC_DEFINE(HAVE_CC_TLS, 1,
+ [Define to 1 if the target assembler supports thread-local storage.])
+ fi])
+
+dnl Check whether TLS is emulated.
+AC_DEFUN([GCC_CHECK_EMUTLS], [
+ AC_CACHE_CHECK([whether the thread-local storage support is from emutls],
+ gcc_cv_use_emutls, [
+ gcc_cv_use_emutls=no
+ echo '__thread int a; int b; int main() { return a = b; }' > conftest.c
+ if AC_TRY_COMMAND(${CC-cc} -Werror -S -o conftest.s conftest.c 1>&AS_MESSAGE_LOG_FD); then
+ if grep __emutls_get_address conftest.s > /dev/null; then
+ gcc_cv_use_emutls=yes
+ fi
+ fi
+ rm -f conftest.*
+ ])
+ if test "$gcc_cv_use_emutls" = "yes" ; then
+ AC_DEFINE(USE_EMUTLS, 1,
+ [Define to 1 if the target use emutls for thread-local storage.])
+ fi])
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