23 lines
949 B
Plaintext
23 lines
949 B
Plaintext
dnl Check whether the target supports TLS.
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AC_DEFUN([GCC_CHECK_TLS], [
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GCC_ENABLE(tls, yes, [], [Use thread-local storage])
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AC_CACHE_CHECK([whether the target supports thread-local storage],
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have_tls, [
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AC_RUN_IFELSE([__thread int a; int b; int main() { return a = b; }],
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[dnl If the test case passed with dynamic linking, try again with
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dnl static linking. This fails at least with some older Red Hat
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dnl releases.
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save_LDFLAGS="$LDFLAGS"
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LDFLAGS="-static $LDFLAGS"
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AC_RUN_IFELSE([__thread int a; int b; int main() { return a = b; }],
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[have_tls=yes], [have_tls=no], [])
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LDFLAGS="$save_LDFLAGS"],
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[have_tls=no],
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[AC_LINK_IFELSE([__thread int a; int b; int main() { return a = b; }],
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[have_tls=yes], [have_tls=no])]
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)])
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if test "$enable_tls $have_tls" = "yes yes"; then
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AC_DEFINE(HAVE_TLS, 1,
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[Define to 1 if the target supports thread-local storage.])
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fi])
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