oops: still need compiler barriers!

bee92013 · Nickolai Zeldovich · 1153b3c3 · bee92013 · bee92013
--- a/include/atomic.hh
+++ b/include/atomic.hh
@@ -6,6 +6,7 @@
 #define _GLIBCXX_BEGIN_EXTERN_C extern "C" {
 #define _GLIBCXX_END_EXTERN_C }
 #define __glibcxx_assert(x)
+#define __barrier() do { __asm__ __volatile__("" ::: "memory"); } while (0)

 #define _GLIBCXX_ATOMIC_BUILTINS_1 1
 #define _GLIBCXX_ATOMIC_BUILTINS_2 1

--- a/include/atomic_2.h
+++ b/include/atomic_2.h
@@ -285,8 +285,10 @@ namespace __atomic2
 	__glibcxx_assert(__m != memory_order_acq_rel);

 	// __sync_synchronize();
+        __barrier();
 	__int_type __ret = _M_i;
 	// __sync_synchronize();
+        __barrier();
 	return __ret;
      }

@@ -297,8 +299,10 @@ namespace __atomic2
 	__glibcxx_assert(__m != memory_order_acq_rel);

 	// __sync_synchronize();
+        __barrier();
 	__int_type __ret = _M_i;
 	// __sync_synchronize();
+        __barrier();
 	return __ret;
      }

@@ -577,8 +581,10 @@ namespace __atomic2
 	__glibcxx_assert(__m != memory_order_acq_rel);

 	// __sync_synchronize();
+        __barrier();
 	__pointer_type __ret = _M_p;
 	// __sync_synchronize();
+        __barrier();
 	return __ret;
      }

@@ -589,8 +595,10 @@ namespace __atomic2
 	__glibcxx_assert(__m != memory_order_acq_rel);

 	// __sync_synchronize();
+        __barrier();
 	__pointer_type __ret = _M_p;
 	// __sync_synchronize();
+        __barrier();
 	return __ret;
      }