From dbd34b899f1ec8facc25649349cda3ffe482b3bf Mon Sep 17 00:00:00 2001 From: Iain Sandoe Date: Wed, 9 Jun 2010 09:27:04 +0000 Subject: re PR bootstrap/43170 (gcc 4.5 20100218 bootstrap compare fails on os x 10.6) config: PR bootstrap/43170 * tls.m4 (GCC_CHECK_TLS): Add volatile qualifier to the test references. Move the main () test reference ahead of pthread_create(). Add a comment to explain the requirements of the test. libgomp: PR bootstrap/43170 * configure: Regenerate. libjava: PR bootstrap/43170 * configure: Regenerate. libmudflap: PR bootstrap/43170 * configure: Regenerate. libstdc++-v3: PR bootstrap/43170 * configure: Regenerate. From-SVN: r160457 --- config/tls.m4 | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) (limited to 'config/tls.m4') diff --git a/config/tls.m4 b/config/tls.m4 index ef7e6d0..4e170c8 100644 --- a/config/tls.m4 +++ b/config/tls.m4 @@ -38,11 +38,16 @@ AC_DEFUN([GCC_CHECK_TLS], [ CFLAGS="$chktls_save_CFLAGS" if test "X$thread_CFLAGS" != Xfailed; then CFLAGS="$thread_CFLAGS $chktls_save_CFLAGS" + dnl Test for an old glibc bug that violated the __thread property. + dnl Use volatile to ensure the compiler won't optimize away pointer + dnl accesses it might otherwise assume to be redundant, or reorder + dnl them and reuse storage, which might lead to them pointing to + dnl the same location. AC_RUN_IFELSE( [AC_LANG_PROGRAM( [#include __thread int a; - static int *a_in_other_thread; + static int *volatile a_in_other_thread; static void * thread_func (void *arg) { @@ -51,11 +56,11 @@ AC_DEFUN([GCC_CHECK_TLS], [ }], [pthread_t thread; void *thread_retval; - int *a_in_main_thread; + int *volatile a_in_main_thread; + a_in_main_thread = &a; 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);])], -- cgit v1.1