Use __atomic_exchange_n instead of Clang's __sync_swap

Also remove an extra extern "C" from a global variable redeclaration.
This allows building libcxxabi with GCC on my system.

Reviewers: majnemer

Differential Revision: http://reviews.llvm.org/D5604

llvm-svn: 219012

1 files changed, 8 insertions, 6 deletions

diff --git a/libcxxabi/src/cxa_default_handlers.cpp b/libcxxabi/src/cxa_default_handlers.cpp
index a26ea2a05b6..d34341aa328 100644
--- a/libcxxabi/src/cxa_default_handlers.cpp
+++ b/libcxxabi/src/cxa_default_handlers.cpp
@@ -101,9 +101,10 @@ namespace std
 unexpected_handler
 set_unexpected(unexpected_handler func) _NOEXCEPT
 {
-	if (func == 0)
-		func = default_unexpected_handler;
-	return __sync_swap(&__cxa_unexpected_handler, func);
+    if (func == 0)
+        func = default_unexpected_handler;
+    return __atomic_exchange_n(&__cxa_unexpected_handler, func,
+                               __ATOMIC_ACQ_REL);
 //  Using of C++11 atomics this should be rewritten
 //  return __cxa_unexpected_handler.exchange(func, memory_order_acq_rel);
 }
@@ -111,9 +112,10 @@ set_unexpected(unexpected_handler func) _NOEXCEPT
 terminate_handler
 set_terminate(terminate_handler func) _NOEXCEPT
 {
-	if (func == 0)
-		func = default_terminate_handler;
-	return __sync_swap(&__cxa_terminate_handler, func);
+    if (func == 0)
+        func = default_terminate_handler;
+    return __atomic_exchange_n(&__cxa_terminate_handler, func,
+                               __ATOMIC_ACQ_REL);
 //  Using of C++11 atomics this should be rewritten
 //  return __cxa_terminate_handler.exchange(func, memory_order_acq_rel);
 }