Mercurial > hg > CbC > CbC_gcc
diff config/tls.m4 @ 67:f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
| author | nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp> |
|---|---|
| date | Tue, 22 Mar 2011 17:18:12 +0900 |
| parents | 77e2b8dfacca |
| children | 1830386684a0 |
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--- a/config/tls.m4 Tue May 25 18:58:51 2010 +0900 +++ b/config/tls.m4 Tue Mar 22 17:18:12 2011 +0900 @@ -38,11 +38,16 @@ 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 <pthread.h> __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 @@ }], [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);])],