commit 74f4da7219100afcff4baab33d12910d29eb127e
author Howard Hinnant <hhinnant@apple.com> Thu May 02 20:18:43 2013 +0000
committer Howard Hinnant <hhinnant@apple.com> Thu May 02 20:18:43 2013 +0000
tree 49dd83bd8829a518724301a7756a089e297e6cbd
parent e58bc12f2aa9548ec3c5fe657dffa2024b5926c1

Stephan Tolksdorf: fixes the issue in the <atomic> header and adds corresponding tests. I've used macros to fall back to a user-provided default constructor if _LIBCPP_HAS_NO_DEFAULTED_FUNCTIONS (though I suspect that there won't be many users defining that macro).

The tests use placement new to check that atomic values get properly zero-initialized. I had to modify the atomic_is_lock_free test, because default initialization of an object of const type 'const A' (aka 'const atomic<int>') requires a user-provided default constructor.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@180945 91177308-0d34-0410-b5e6-96231b3b80d8

include/atomic

diff --git a/include/atomic b/include/atomic
index db67e76..f6ab1cb 100644
--- a/include/atomic
+++ b/include/atomic
@@ -622,7 +622,12 @@
         {return __c11_atomic_compare_exchange_strong(&__a_, &__e, __d, __m, __m);}
 
     _LIBCPP_INLINE_VISIBILITY
-    __atomic_base() _NOEXCEPT {} // = default;
+#ifndef _LIBCPP_HAS_NO_DEFAULTED_FUNCTIONS
+    __atomic_base() _NOEXCEPT = default;
+#else
+    __atomic_base() _NOEXCEPT : __a_() {}
+#endif // _LIBCPP_HAS_NO_DEFAULTED_FUNCTIONS
+
     _LIBCPP_INLINE_VISIBILITY
     _LIBCPP_CONSTEXPR __atomic_base(_Tp __d) _NOEXCEPT : __a_(__d) {}
 #ifndef _LIBCPP_HAS_NO_DELETED_FUNCTIONS
@@ -645,7 +650,7 @@
 {
     typedef __atomic_base<_Tp, false> __base;
     _LIBCPP_INLINE_VISIBILITY
-    __atomic_base() _NOEXCEPT {} // = default;
+    __atomic_base() _NOEXCEPT _LIBCPP_DEFAULT
     _LIBCPP_INLINE_VISIBILITY
     _LIBCPP_CONSTEXPR __atomic_base(_Tp __d) _NOEXCEPT : __base(__d) {}
 
@@ -726,7 +731,7 @@
 {
     typedef __atomic_base<_Tp> __base;
     _LIBCPP_INLINE_VISIBILITY
-    atomic() _NOEXCEPT {} // = default;
+    atomic() _NOEXCEPT _LIBCPP_DEFAULT
     _LIBCPP_INLINE_VISIBILITY
     _LIBCPP_CONSTEXPR atomic(_Tp __d) _NOEXCEPT : __base(__d) {}
 
@@ -746,7 +751,7 @@
 {
     typedef __atomic_base<_Tp*> __base;
     _LIBCPP_INLINE_VISIBILITY
-    atomic() _NOEXCEPT {} // = default;
+    atomic() _NOEXCEPT _LIBCPP_DEFAULT
     _LIBCPP_INLINE_VISIBILITY
     _LIBCPP_CONSTEXPR atomic(_Tp* __d) _NOEXCEPT : __base(__d) {}
 
@@ -1367,7 +1372,12 @@
         {__c11_atomic_store(&__a_, false, __m);}
 
     _LIBCPP_INLINE_VISIBILITY
-    atomic_flag() _NOEXCEPT {} // = default;
+#ifndef _LIBCPP_HAS_NO_DEFAULTED_FUNCTIONS
+    atomic_flag() _NOEXCEPT = default;
+#else
+    atomic_flag() _NOEXCEPT : __a_() {}
+#endif // _LIBCPP_HAS_NO_DEFAULTED_FUNCTIONS
+
     _LIBCPP_INLINE_VISIBILITY
     atomic_flag(bool __b) _NOEXCEPT : __a_(__b) {}