diff options
Diffstat (limited to 'config/tls.m4')
| -rw-r--r-- | config/tls.m4 | 70 |
1 files changed, 62 insertions, 8 deletions
diff --git a/config/tls.m4 b/config/tls.m4 index 5cbb6854f6c78..c8f3ff0a37334 100644 --- a/config/tls.m4 +++ b/config/tls.m4 @@ -1,19 +1,73 @@ dnl Check whether the target supports TLS. AC_DEFUN([GCC_CHECK_TLS], [ - GCC_ENABLE(tls, yes, [Use thread-local storage]) + 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="$LDFLAGS" + dnl static linking, but only if static linking is supported (not + dnl on Solaris 10). This fails with some older Red Hat releases. + chktls_save_LDFLAGS="$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"], + AC_LINK_IFELSE([int main() { return 0; }], + AC_RUN_IFELSE([__thread int a; int b; int main() { return a = b; }], + [have_tls=yes], [have_tls=no],[]), + [have_tls=yes]) + LDFLAGS="$chktls_save_LDFLAGS" + if test $have_tls = yes; then + dnl So far, the binutils and the compiler support TLS. + dnl Also check whether the libc supports TLS, i.e. whether a variable + dnl with __thread linkage has a different address in different threads. + dnl First, find the thread_CFLAGS necessary for linking a program that + dnl calls pthread_create. + chktls_save_CFLAGS="$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 $chktls_save_CFLAGS" + AC_RUN_IFELSE( + [AC_LANG_PROGRAM( + [#include <pthread.h> + __thread int a; + static int *a_in_other_thread; + static void * + thread_func (void *arg) + { + a_in_other_thread = &a; + return (void *)0; + }], + [pthread_t thread; + void *thread_retval; + int *a_in_main_thread; + if (pthread_create (&thread, (pthread_attr_t *)0, + thread_func, (void *)0)) + return 0; + a_in_main_thread = &a; + if (pthread_join (thread, &thread_retval)) + return 0; + return (a_in_other_thread == a_in_main_thread);])], + [have_tls=yes], [have_tls=no], []) + CFLAGS="$chktls_save_CFLAGS" + fi + fi], [have_tls=no], - [AC_COMPILE_IFELSE([__thread int foo;], [have_tls=yes], [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; }], + [have_tls=yes], [have_tls=no]) + ] )]) if test "$enable_tls $have_tls" = "yes yes"; then AC_DEFINE(HAVE_TLS, 1, |