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# Copyright 2012 Intel Corporation
#
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
# - Redistributions of source code must retain the above copyright notice, this
# list of conditions and the following disclaimer.
#
# - Redistributions in binary form must reproduce the above copyright notice,
# this list of conditions and the following disclaimer in the documentation
# and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
# Summary:
# Check if the compiler supports various types of thread-local storage.
#
# Usage:
# include(WaffleCheckThreadLocalStorage)
# waffle_check_thread_local_storage()
#
# Output Variables:
# waffle_has_tls
# True if the compiler supports the `__thread` attribute.
#
# waffle_has_tls_model_initial_exec
# True if the compiler supports `__attribute__(tls_model("initial-exec"))`.
#
include(CheckCSourceCompiles)
macro(waffle_check_thread_local_storage)
# Clang, in its zeal for compatibility with gcc, emits only a warning if
# it encounters an __attribute__ that it does not recognize. To prevent
# this function from returning a false positive in that situation, force
# check_c_source_compiles() to fail on warnings with FAIL_REGEX.
check_c_source_compiles(
"
static __thread int x;
int
main() {
x = 42;
return x;
}
"
waffle_has_tls
FAIL_REGEX "warning: |error: "
)
check_c_source_compiles(
"
static __thread int x __attribute__((tls_model(\"initial-exec\")));
int
main() {
x = 42;
return x;
}
"
waffle_has_tls_model_initial_exec
FAIL_REGEX "warning: |error: "
)
endmacro()
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