| 1 | dnl Check whether the target supports TLS. |
| 2 | AC_DEFUN([GCC_CHECK_TLS], [ |
| 3 | GCC_ENABLE(tls, yes, [], [Use thread-local storage]) |
| 4 | AC_CACHE_CHECK([whether the target supports thread-local storage], |
| 5 | have_tls, [ |
| 6 | AC_RUN_IFELSE([__thread int a; int b; int main() { return a = b; }], |
| 7 | [dnl If the test case passed with dynamic linking, try again with |
| 8 | dnl static linking, but only if static linking is supported (not |
| 9 | dnl on Solaris 10). This fails with some older Red Hat releases. |
| 10 | chktls_save_LDFLAGS="$LDFLAGS" |
| 11 | LDFLAGS="-static $LDFLAGS" |
| 12 | AC_LINK_IFELSE([int main() { return 0; }], |
| 13 | AC_RUN_IFELSE([__thread int a; int b; int main() { return a = b; }], |
| 14 | [have_tls=yes], [have_tls=no],[]), |
| 15 | [have_tls=yes]) |
| 16 | LDFLAGS="$chktls_save_LDFLAGS" |
| 17 | if test $have_tls = yes; then |
| 18 | dnl So far, the binutils and the compiler support TLS. |
| 19 | dnl Also check whether the libc supports TLS, i.e. whether a variable |
| 20 | dnl with __thread linkage has a different address in different threads. |
| 21 | dnl First, find the thread_CFLAGS necessary for linking a program that |
| 22 | dnl calls pthread_create. |
| 23 | chktls_save_CFLAGS="$CFLAGS" |
| 24 | thread_CFLAGS=failed |
| 25 | for flag in '' '-pthread' '-lpthread'; do |
| 26 | CFLAGS="$flag $chktls_save_CFLAGS" |
| 27 | AC_LINK_IFELSE( |
| 28 | [AC_LANG_PROGRAM( |
| 29 | [#include <pthread.h> |
| 30 | void *g(void *d) { return NULL; }], |
| 31 | [pthread_t t; pthread_create(&t,NULL,g,NULL);])], |
| 32 | [thread_CFLAGS="$flag"]) |
| 33 | if test "X$thread_CFLAGS" != Xfailed; then |
| 34 | break |
| 35 | fi |
| 36 | done |
| 37 | CFLAGS="$chktls_save_CFLAGS" |
| 38 | if test "X$thread_CFLAGS" != Xfailed; then |
| 39 | CFLAGS="$thread_CFLAGS $chktls_save_CFLAGS" |
| 40 | AC_RUN_IFELSE( |
| 41 | [AC_LANG_PROGRAM( |
| 42 | [#include <pthread.h> |
| 43 | __thread int a; |
| 44 | static int *a_in_other_thread; |
| 45 | static void * |
| 46 | thread_func (void *arg) |
| 47 | { |
| 48 | a_in_other_thread = &a; |
| 49 | return (void *)0; |
| 50 | }], |
| 51 | [pthread_t thread; |
| 52 | void *thread_retval; |
| 53 | int *a_in_main_thread; |
| 54 | if (pthread_create (&thread, (pthread_attr_t *)0, |
| 55 | thread_func, (void *)0)) |
| 56 | return 0; |
| 57 | a_in_main_thread = &a; |
| 58 | if (pthread_join (thread, &thread_retval)) |
| 59 | return 0; |
| 60 | return (a_in_other_thread == a_in_main_thread);])], |
| 61 | [have_tls=yes], [have_tls=no], []) |
| 62 | CFLAGS="$chktls_save_CFLAGS" |
| 63 | fi |
| 64 | fi], |
| 65 | [have_tls=no], |
| 66 | [dnl This is the cross-compiling case. Assume libc supports TLS if the |
| 67 | dnl binutils and the compiler do. |
| 68 | AC_LINK_IFELSE([__thread int a; int b; int main() { return a = b; }], |
| 69 | [have_tls=yes], [have_tls=no]) |
| 70 | ] |
| 71 | )]) |
| 72 | if test "$enable_tls $have_tls" = "yes yes"; then |
| 73 | AC_DEFINE(HAVE_TLS, 1, |
| 74 | [Define to 1 if the target supports thread-local storage.]) |
| 75 | fi]) |
| 76 | |
| 77 | dnl Check whether the target assembler supports TLS. |
| 78 | AC_DEFUN([GCC_CHECK_CC_TLS], [ |
| 79 | GCC_ENABLE(tls, yes, [], [Use thread-local storage]) |
| 80 | AC_CACHE_CHECK([whether the target asssembler upports thread-local storage], |
| 81 | have_cc_tls, [ |
| 82 | AC_COMPILE_IFELSE([__thread int a; int b; int main() { return a = b; }], |
| 83 | [have_cc_tls=yes], [have_cc_tls=no])] |
| 84 | )]) |
| 85 | if test "$enable_tls $have_cc_tls" = "yes yes"; then |
| 86 | AC_DEFINE(HAVE_CC_TLS, 1, |
| 87 | [Define to 1 if the target assembler supports thread-local storage.]) |
| 88 | fi]) |