diff options
Diffstat (limited to 'cmake/FindAtomic.cmake')
-rw-r--r-- | cmake/FindAtomic.cmake | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/cmake/FindAtomic.cmake b/cmake/FindAtomic.cmake new file mode 100644 index 0000000000..91cee62046 --- /dev/null +++ b/cmake/FindAtomic.cmake @@ -0,0 +1,44 @@ +# We can't create the same interface imported target multiple times, CMake will complain if we do +# that. This can happen if the find_package call is done in multiple different subdirectories. +if(TARGET Atomic) + set(Atomic_FOUND ON) + return() +endif() + +include(CheckCXXSourceCompiles) + +set (atomic_test_sources "#include <atomic> +#include <cstdint> + +void test(volatile std::atomic<std::int64_t> &a) +{ + std::int64_t v = a.load(std::memory_order_acquire); + while (!a.compare_exchange_strong(v, v + 1, + std::memory_order_acq_rel, + std::memory_order_acquire)) { + v = a.exchange(v - 1); + } + a.store(v + 1, std::memory_order_release); +} + +int main(int, char **) +{ + void *ptr = (void*)0xffffffc0; // any random pointer + test(*reinterpret_cast<std::atomic<std::int64_t> *>(ptr)); + return 0; +}") + +check_cxx_source_compiles("${atomic_test_sources}" HAVE_STDATOMIC) +if(NOT HAVE_STDATOMIC) + set(_req_libraries "${CMAKE_REQUIRE_LIBRARIES}") + set(CMAKE_REQUIRE_LIBRARIES "atomic") + check_cxx_source_compiles("${atomic_test_sources}" HAVE_STDATOMIC_WITH_LIB) + set(CMAKE_REQUIRE_LIBRARIES "${_req_libraries}") +endif() + +add_library(Atomic INTERFACE IMPORTED) +if(HAVE_STDATOMIC_WITH_LIB) + target_link_libraries(Atomic INTERFACE atomic) +endif() + +set(Atomic_FOUND 1) |