X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=cmake%2Fmodules%2FCheckAtomic.cmake;fp=cmake%2Fmodules%2FCheckAtomic.cmake;h=27bbaba6998c99416a56a151ffd8cbf697216d17;hb=6215c6227e788c7c13d5d83d469e5b0019a0f1af;hp=0000000000000000000000000000000000000000;hpb=d8aa9fc06274604eae2b5156045a71857a8f18c4;p=oota-llvm.git

diff --git a/cmake/modules/CheckAtomic.cmake b/cmake/modules/CheckAtomic.cmake
new file mode 100644
index 00000000000..27bbaba6998
--- /dev/null
+++ b/cmake/modules/CheckAtomic.cmake
@@ -0,0 +1,18 @@
+# atomic builtins are required for threading support.
+
+INCLUDE(CheckCXXSourceCompiles)
+	
+CHECK_CXX_SOURCE_COMPILES("
+int main() {
+        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);
+        return 0;
+      }
+" LLVM_MULTITHREADED)
+
+if( NOT LLVM_MULTITHREADED )
+  message(STATUS "Warning: LLVM will be built thread-unsafe because atomic builtins are missing")
+endif()