Commit | Line | Data |
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11c94d12 TT |
1 | dnl Check whether the target supports TLS. |
2 | AC_DEFUN([GCC_CHECK_TLS], [ | |
98c5f827 | 3 | GCC_ENABLE(tls, yes, [], [Use thread-local storage]) |
11c94d12 TT |
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. This fails at least with some older Red Hat | |
9 | dnl releases. | |
10 | save_LDFLAGS="$LDFLAGS" | |
11 | LDFLAGS="-static $LDFLAGS" | |
12 | AC_RUN_IFELSE([__thread int a; int b; int main() { return a = b; }], | |
13 | [have_tls=yes], [have_tls=no], []) | |
14 | LDFLAGS="$save_LDFLAGS"], | |
15 | [have_tls=no], | |
7173306d DJ |
16 | [AC_LINK_IFELSE([__thread int a; int b; int main() { return a = b; }], |
17 | [have_tls=yes], [have_tls=no])] | |
11c94d12 TT |
18 | )]) |
19 | if test "$enable_tls $have_tls" = "yes yes"; then | |
20 | AC_DEFINE(HAVE_TLS, 1, | |
21 | [Define to 1 if the target supports thread-local storage.]) | |
22 | fi]) |