| # atomic builtins are required for threading support. |
| |
| INCLUDE(CheckCXXSourceCompiles) |
| |
| CHECK_CXX_SOURCE_COMPILES(" |
| #ifdef _MSC_VER |
| #include <windows.h> |
| #endif |
| int main() { |
| #ifdef _MSC_VER |
| volatile LONG val = 1; |
| MemoryBarrier(); |
| InterlockedCompareExchange(&val, 0, 1); |
| InterlockedIncrement(&val); |
| InterlockedDecrement(&val); |
| #else |
| volatile unsigned long val = 1; |
| __sync_synchronize(); |
| __sync_val_compare_and_swap(&val, 1, 0); |
| __sync_add_and_fetch(&val, 1); |
| __sync_sub_and_fetch(&val, 1); |
| #endif |
| return 0; |
| } |
| " LLVM_HAS_ATOMICS) |
| |
| if( NOT LLVM_HAS_ATOMICS ) |
| message(STATUS "Warning: LLVM will be built thread-unsafe because atomic builtins are missing") |
| endif() |
