Still working on the basic design of <atomic>. I'm working towards a system by which the compiler only needs to define the strongest intrinsics it can. Weaker atomics in the library automatically try stronger and stronger variants, picking the weakest compiler intrinsic available. If no compiler intrinsics are available for a given operation, the library locks a mutex and does the job. Better documentation to follow...

llvm-svn: 115538

1 files changed, 23 insertions, 0 deletions

diff --git a/libcxx/src/atomic.cpp b/libcxx/src/atomic.cpp
new file mode 100644
index 00000000000..dc354df2303
--- /dev/null
+++ b/libcxx/src/atomic.cpp
@@ -0,0 +1,23 @@
+//===------------------------- atomic.cpp ---------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "__mutex_base"
+#include "atomic"
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+_LIBCPP_VISIBLE
+mutex&
+__not_atomic_mut()
+{
+    static mutex m;
+    return m;
+}
+
+_LIBCPP_END_NAMESPACE_STD