[libcxx] Allow use of <atomic> in C++03. Try 3.

[EricWF]

Summary

After putting this question up on cfe-dev I have decided that it would be best to allow the use of <atomic> in C++03. Although static initialization is a concern the syntax required to get it is C++11 only. Meaning that C++11 constant static initialization cannot silently break in C++03, it will always cause a syntax error. Furthermore ATOMIC_VAR_INIT and ATOMIC_FLAG_INIT remain defined in C++03 even though they cannot be used because C++03 usages will cause better error messages.

The main change in this patch is to replace __has_feature(cxx_atomic), which only returns true when C++ >= 11, to __has_extension(c_atomic) which returns true whenever clang supports the required atomic builtins.

This patch adds the following macros:

• _LIBCPP_HAS_C_ATOMIC_IMP - Defined on clang versions which provide the C _Atomic keyword.
• _LIBCPP_HAS_GCC_ATOMIC_IMP - Defined on GCC > 4.7. We must use the fallback atomic implementation.
• _LIBCPP_HAS_NO_ATOMIC_HEADER - Defined when it is not safe to include <atomic>.

_LIBCPP_HAS_C_ATOMIC_IMP and _LIBCPP_HAS_GCC_ATOMIC_IMP are mutually exclusive, only one should be defined. If neither is defined then <atomic> is not implemented and including <atomic> will issue an error.

[mclow.lists]

In general, this is looking quite good.

include/ios

373

Do you need to address this TODO before committing? (and the one in <memory> ?)

test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_helpers.h

42

Is there a way to do this w/o exposing the name test here?
Maybe a type list and then apply-ing to to each member of the type list?

[EricWF]

• Address review comments.

[EricWF]

That last patch had a bunch of junk in it. My mistake. This patch is better.

[EricWF]

include/ios

373

Do you need to address this TODO before committing?

I would rather make the change in the TODO separately. I want to be sure that enabling this for both the Clang and GCC implementations of atomic will not cause ODR or ABI problems. I think these concerns should be addressed in a different patch.

[mclow.lists]

I think this is ready to land now. Thanks, Eric.

include/__config

 #ifndef __has_builtin
 #define __has_builtin(__x) 0
 #endif
+#ifndef __has_extension
+#define __has_extension(__x) 0
+#endif
 #ifndef __has_feature
 #define __has_feature(__x) 0
 #endif

 #define _LIBCPP_HAS_NO_THREAD_UNSAFE_C_FUNCTIONS
 #endif
 
-#endif  // _LIBCPP_CONFIG
+#if __has_extension(c_atomic)
+#define _LIBCPP_HAS_C_ATOMIC_IMP
+#elif _GNUC_VER > 407
+#define _LIBCPP_HAS_GCC_ATOMIC_IMP
+#endif
+
+#if (!defined(_LIBCPP_HAS_C_ATOMIC_IMP) && !defined(_LIBCPP_HAS_GCC_ATOMIC_IMP)) \
+     || defined(_LIBCPP_HAS_NO_THREADS)
+#define _LIBCPP_HAS_NO_ATOMIC_HEADER
+#endif
+
+#endif // _LIBCPP_CONFIG

include/atomic

 
 #ifdef _LIBCPP_HAS_NO_THREADS
 #error <atomic> is not supported on this single threaded system
-#else // !_LIBCPP_HAS_NO_THREADS
+#endif
+#if !defined(_LIBCPP_HAS_C_ATOMIC_IMP) && !defined(_LIBCPP_HAS_GCC_ATOMIC_IMP)
+#error <atomic> is not implemented
+#endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if !__has_feature(cxx_atomic) && _GNUC_VER < 407
-#error <atomic> is not implemented
-#else
-
 typedef enum memory_order
 {
     memory_order_relaxed, memory_order_consume, memory_order_acquire,
     memory_order_release, memory_order_acq_rel, memory_order_seq_cst
 } memory_order;
 
-#if _GNUC_VER >= 407
+#if defined(_LIBCPP_HAS_GCC_ATOMIC_IMP)
 namespace __gcc_atomic {
 template <typename _Tp>
 struct __gcc_atomic_t {

   return __atomic_fetch_xor(&__a->__a_value, __pattern,
                             __gcc_atomic::__to_gcc_order(__order));
 }
-#endif // _GNUC_VER >= 407
+#endif // _LIBCPP_HAS_GCC_ATOMIC_IMP
 
 template <class _Tp>
 inline _LIBCPP_INLINE_VISIBILITY

     _LIBCPP_INLINE_VISIBILITY
     bool is_lock_free() const volatile _NOEXCEPT
     {
-#if __has_feature(cxx_atomic)
+#if defined(_LIBCPP_HAS_C_ATOMIC_IMP)
     return __c11_atomic_is_lock_free(sizeof(_Tp));
 #else
     return __atomic_is_lock_free(sizeof(_Tp), 0);

 #define ATOMIC_FLAG_INIT {false}
 #define ATOMIC_VAR_INIT(__v) {__v}
 
-// lock-free property
-
 #define ATOMIC_BOOL_LOCK_FREE      __GCC_ATOMIC_BOOL_LOCK_FREE
 #define ATOMIC_CHAR_LOCK_FREE      __GCC_ATOMIC_CHAR_LOCK_FREE
 #define ATOMIC_CHAR16_T_LOCK_FREE  __GCC_ATOMIC_CHAR16_T_LOCK_FREE

 #define ATOMIC_LLONG_LOCK_FREE     __GCC_ATOMIC_LLONG_LOCK_FREE
 #define ATOMIC_POINTER_LOCK_FREE   __GCC_ATOMIC_POINTER_LOCK_FREE
 
-#endif  //  !__has_feature(cxx_atomic)
-
 _LIBCPP_END_NAMESPACE_STD
 
-#endif  // !_LIBCPP_HAS_NO_THREADS
-
 #endif  // _LIBCPP_ATOMIC

include/ios

 #include <__locale>
 #include <system_error>
 
-#if __has_feature(cxx_atomic) && !defined(_LIBCPP_HAS_NO_THREADS)
+#if !defined(_LIBCPP_HAS_NO_ATOMIC_HEADER)
 #include <atomic>     // for __xindex_
 #endif
 

     int*            __index_;
     size_t          __event_size_;
     size_t          __event_cap_;
-#if __has_feature(cxx_atomic) && !defined(_LIBCPP_HAS_NO_THREADS)
+// TODO(EricWF): Enable this for both Clang and GCC. Currently it is only
+// enabled with clang.
+#if defined(_LIBCPP_HAS_C_ATOMIC_IMP) && !defined(_LIBCPP_HAS_NO_THREADS)
     static atomic<int> __xindex_;
 #else
     static int      __xindex_;

include/memory

     #include <cassert>
 #endif
 
-#if __has_feature(cxx_atomic) && !defined(_LIBCPP_HAS_NO_THREADS)
+#if !defined(_LIBCPP_HAS_NO_ATOMIC_HEADER)
 #  include <atomic>
 #endif
 

 basic_ostream<_CharT, _Traits>&
 operator<<(basic_ostream<_CharT, _Traits>& __os, shared_ptr<_Yp> const& __p);
 
-#if __has_feature(cxx_atomic) && !defined(_LIBCPP_HAS_NO_THREADS)
+// TODO(EricWF): Enable this for both Clang and GCC. Currently it is only
+// enabled with clang.
+#if defined(_LIBCPP_HAS_C_ATOMIC_IMP) && !defined(_LIBCPP_HAS_NO_THREADS)
 
 class _LIBCPP_TYPE_VIS __sp_mut
 {

     return atomic_compare_exchange_weak(__p, __v, __w);
 }
 
-#endif  // __has_feature(cxx_atomic) && !defined(_LIBCPP_HAS_NO_THREADS)
+#endif  // defined(_LIBCPP_HAS_C_ATOMIC_IMP) && !defined(_LIBCPP_HAS_NO_THREADS)
 
 //enum class
 struct _LIBCPP_TYPE_VIS pointer_safety

src/ios.cpp

 }
 
 // xalloc
-#if __has_feature(cxx_atomic) && !defined(_LIBCPP_HAS_NO_THREADS)
+#if defined(_LIBCPP_HAS_C_ATOMIC_IMP) && !defined(_LIBCPP_HAS_NO_THREADS)
 atomic<int> ios_base::__xindex_ = ATOMIC_VAR_INIT(0);
 #else
 int ios_base::__xindex_ = 0;

src/memory.cpp

 
 #endif  // _LIBCPP_NO_RTTI
 
-#if __has_feature(cxx_atomic) && !defined(_LIBCPP_HAS_NO_THREADS)
+#if defined(_LIBCPP_HAS_C_ATOMIC_IMP) && !defined(_LIBCPP_HAS_NO_THREADS)
 
 static const std::size_t __sp_mut_count = 16;
 static pthread_mutex_t mut_back_imp[__sp_mut_count] =

     return muts[hash<const void*>()(p) & (__sp_mut_count-1)];
 }
 
-#endif // __has_feature(cxx_atomic) && !_LIBCPP_HAS_NO_THREADS
+#endif // defined(_LIBCPP_HAS_C_ATOMIC_IMP) && !defined(_LIBCPP_HAS_NO_THREADS)
 
 void
 declare_reachable(void*)

test/std/atomics/atomics.flag/atomic_flag_clear.pass.cpp

 int main()
 {
     {
-        std::atomic_flag f = ATOMIC_FLAG_INIT;
+        std::atomic_flag f(false);
         f.test_and_set();
         atomic_flag_clear(&f);
         assert(f.test_and_set() == 0);
     }
     {
-        volatile std::atomic_flag f = ATOMIC_FLAG_INIT;
+        volatile std::atomic_flag f(false);
         f.test_and_set();
         atomic_flag_clear(&f);
         assert(f.test_and_set() == 0);

test/std/atomics/atomics.flag/atomic_flag_clear_explicit.pass.cpp

 int main()
 {
     {
-        std::atomic_flag f = ATOMIC_FLAG_INIT;
+        std::atomic_flag f(false);
         f.test_and_set();
         atomic_flag_clear_explicit(&f, std::memory_order_relaxed);
         assert(f.test_and_set() == 0);
     }
     {
-        std::atomic_flag f = ATOMIC_FLAG_INIT;
+        std::atomic_flag f(false);
         f.test_and_set();
         atomic_flag_clear_explicit(&f, std::memory_order_release);
         assert(f.test_and_set() == 0);
     }
     {
-        std::atomic_flag f = ATOMIC_FLAG_INIT;
+        std::atomic_flag f(false);
         f.test_and_set();
         atomic_flag_clear_explicit(&f, std::memory_order_seq_cst);
         assert(f.test_and_set() == 0);
     }
     {
-        volatile std::atomic_flag f = ATOMIC_FLAG_INIT;
+        volatile std::atomic_flag f(false);
         f.test_and_set();
         atomic_flag_clear_explicit(&f, std::memory_order_relaxed);
         assert(f.test_and_set() == 0);
     }
     {
-        volatile std::atomic_flag f = ATOMIC_FLAG_INIT;
+        volatile std::atomic_flag f(false);
         f.test_and_set();
         atomic_flag_clear_explicit(&f, std::memory_order_release);
         assert(f.test_and_set() == 0);
     }
     {
-        volatile std::atomic_flag f = ATOMIC_FLAG_INIT;
+        volatile std::atomic_flag f(false);
         f.test_and_set();
         atomic_flag_clear_explicit(&f, std::memory_order_seq_cst);
         assert(f.test_and_set() == 0);

test/std/atomics/atomics.flag/clear.pass.cpp

 int main()
 {
     {
-        std::atomic_flag f = ATOMIC_FLAG_INIT;
+        std::atomic_flag f(false);
         f.test_and_set();
         f.clear();
         assert(f.test_and_set() == 0);
     }
     {
-        std::atomic_flag f = ATOMIC_FLAG_INIT;
+        std::atomic_flag f(false);
         f.test_and_set();
         f.clear(std::memory_order_relaxed);
         assert(f.test_and_set() == 0);
     }
     {
-        std::atomic_flag f = ATOMIC_FLAG_INIT;
+        std::atomic_flag f(false);
         f.test_and_set();
         f.clear(std::memory_order_release);
         assert(f.test_and_set() == 0);
     }
     {
-        std::atomic_flag f = ATOMIC_FLAG_INIT;
+        std::atomic_flag f(false);
         f.test_and_set();
         f.clear(std::memory_order_seq_cst);
         assert(f.test_and_set() == 0);
     }
     {
-        volatile std::atomic_flag f = ATOMIC_FLAG_INIT;
+        volatile std::atomic_flag f(false);
         f.test_and_set();
         f.clear();
         assert(f.test_and_set() == 0);
     }
     {
-        volatile std::atomic_flag f = ATOMIC_FLAG_INIT;
+        volatile std::atomic_flag f(false);
         f.test_and_set();
         f.clear(std::memory_order_relaxed);
         assert(f.test_and_set() == 0);
     }
     {
-        volatile std::atomic_flag f = ATOMIC_FLAG_INIT;
+        volatile std::atomic_flag f(false);
         f.test_and_set();
         f.clear(std::memory_order_release);
         assert(f.test_and_set() == 0);
     }
     {
-        volatile std::atomic_flag f = ATOMIC_FLAG_INIT;
+        volatile std::atomic_flag f(false);
         f.test_and_set();
         f.clear(std::memory_order_seq_cst);
         assert(f.test_and_set() == 0);

test/std/atomics/atomics.flag/init.pass.cpp

 //===----------------------------------------------------------------------===//
 //
 // UNSUPPORTED: libcpp-has-no-threads
+// XFAIL: c++98, c++03
 
 // <atomic>
 

test/std/atomics/atomics.flag/init03.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// UNSUPPORTED: libcpp-has-no-threads
+
+// <atomic>
+
+// struct atomic_flag
+
+// TESTING EXTENSION atomic_flag(bool)
+
+#include <atomic>
+#include <cassert>
+
+int main()
+{
+    std::atomic_flag f(false);
+    assert(f.test_and_set() == 0);
+}

test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_compare_exchange_strong.pass.cpp

 #include <type_traits>
 #include <cassert>
 
+#include "atomic_helpers.h"
+
 template <class T>
-void
-test()
-{
+struct TestFn {
+  void operator()() const {
     {
         typedef std::atomic<T> A;
         A a;

         assert(a == T(2));
         assert(t == T(2));
     }
   }
-
-struct A
-{
-    int i;
-
-    explicit A(int d = 0) noexcept {i=d;}
-
-    friend bool operator==(const A& x, const A& y)
-        {return x.i == y.i;}
 };
 
 int main()
 {
-    test<A>();
-    test<char>();
-    test<signed char>();
-    test<unsigned char>();
-    test<short>();
-    test<unsigned short>();
-    test<int>();
-    test<unsigned int>();
-    test<long>();
-    test<unsigned long>();
-    test<long long>();
-    test<unsigned long long>();
-    test<wchar_t>();
-#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
-    test<char16_t>();
-    test<char32_t>();
-#endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
-    test<int*>();
-    test<const int*>();
+    TestEachAtomicType<TestFn>()();
 }

test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_compare_exchange_strong_explicit.pass.cpp

 #include <type_traits>
 #include <cassert>
 
+#include "atomic_helpers.h"
+
 template <class T>
-void
-test()
-{
+struct TestFn {
+  void operator()() const {
     {
         typedef std::atomic<T> A;
         A a;

         assert(a == T(2));
         assert(t == T(2));
     }
   }
-
-struct A
-{
-    int i;
-
-    explicit A(int d = 0) noexcept {i=d;}
-
-    friend bool operator==(const A& x, const A& y)
-        {return x.i == y.i;}
 };
 
 int main()
 {
-    test<A>();
-    test<char>();
-    test<signed char>();
-    test<unsigned char>();
-    test<short>();
-    test<unsigned short>();
-    test<int>();
-    test<unsigned int>();
-    test<long>();
-    test<unsigned long>();
-    test<long long>();
-    test<unsigned long long>();
-    test<wchar_t>();
-#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
-    test<char16_t>();
-    test<char32_t>();
-#endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
-    test<int*>();
-    test<const int*>();
+    TestEachAtomicType<TestFn>()();
 }

test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_compare_exchange_weak.pass.cpp

 #include <cassert>
 
 #include <cmpxchg_loop.h>
+#include "atomic_helpers.h"
 
 template <class T>
-void
-test()
-{
+struct TestFn {
+  void operator()() const {
     {
         typedef std::atomic<T> A;
         A a;

         assert(a == T(2));
         assert(t == T(2));
     }
   }
-
-struct A
-{
-    int i;
-
-    explicit A(int d = 0) noexcept {i=d;}
-
-    friend bool operator==(const A& x, const A& y)
-        {return x.i == y.i;}
 };
 
 int main()
 {
-    test<A>();
-    test<char>();
-    test<signed char>();
-    test<unsigned char>();
-    test<short>();
-    test<unsigned short>();
-    test<int>();
-    test<unsigned int>();
-    test<long>();
-    test<unsigned long>();
-    test<long long>();
-    test<unsigned long long>();
-    test<wchar_t>();
-#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
-    test<char16_t>();
-    test<char32_t>();
-#endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
-    test<int*>();
-    test<const int*>();
+    TestEachAtomicType<TestFn>()();
 }

test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_compare_exchange_weak_explicit.pass.cpp

 
 #include <cmpxchg_loop.h>
 
+#include "atomic_helpers.h"
+
 template <class T>
-void
-test()
-{
+struct TestFn {
+  void operator()() const {
     {
         typedef std::atomic<T> A;
         A a;

         assert(a == T(2));
         assert(t == T(2));
     }
   }
-
-struct A
-{
-    int i;
-
-    explicit A(int d = 0) noexcept {i=d;}
-
-    friend bool operator==(const A& x, const A& y)
-        {return x.i == y.i;}
 };
 
 int main()
 {
-    test<A>();
-    test<char>();
-    test<signed char>();
-    test<unsigned char>();
-    test<short>();
-    test<unsigned short>();
-    test<int>();
-    test<unsigned int>();
-    test<long>();
-    test<unsigned long>();
-    test<long long>();
-    test<unsigned long long>();
-    test<wchar_t>();
-#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
-    test<char16_t>();
-    test<char32_t>();
-#endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
-    test<int*>();
-    test<const int*>();
+    TestEachAtomicType<TestFn>()();
 }

test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_exchange.pass.cpp

 #include <type_traits>
 #include <cassert>
 
+#include "atomic_helpers.h"
+
 template <class T>
-void
-test()
-{
+struct TestFn {
+  void operator()() const {
     typedef std::atomic<T> A;
     A t;
     std::atomic_init(&t, T(1));

     std::atomic_init(&vt, T(3));
     assert(std::atomic_exchange(&vt, T(4)) == T(3));
     assert(vt == T(4));
   }
-
-struct A
-{
-    int i;
-
-    explicit A(int d = 0) noexcept {i=d;}
-
-    friend bool operator==(const A& x, const A& y)
-        {return x.i == y.i;}
 };
 
+
 int main()
 {
-    test<A>();
-    test<char>();
-    test<signed char>();
-    test<unsigned char>();
-    test<short>();
-    test<unsigned short>();
-    test<int>();
-    test<unsigned int>();
-    test<long>();
-    test<unsigned long>();
-    test<long long>();
-    test<unsigned long long>();
-    test<wchar_t>();
-#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
-    test<char16_t>();
-    test<char32_t>();
-#endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
-    test<int*>();
-    test<const int*>();
+    TestEachAtomicType<TestFn>()();
 }

test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_exchange_explicit.pass.cpp

 #include <type_traits>
 #include <cassert>
 
+#include "atomic_helpers.h"
+
 template <class T>
-void
-test()
-{
+struct TestFn {
+  void operator()() const {
     typedef std::atomic<T> A;
     A t;
     std::atomic_init(&t, T(1));

     assert(std::atomic_exchange_explicit(&vt, T(4), std::memory_order_seq_cst)
            == T(3));
     assert(vt == T(4));
   }
-
-struct A
-{
-    int i;
-
-    explicit A(int d = 0) noexcept {i=d;}
-
-    friend bool operator==(const A& x, const A& y)
-        {return x.i == y.i;}
 };
 
+
 int main()
 {
-    test<A>();
-    test<char>();
-    test<signed char>();
-    test<unsigned char>();
-    test<short>();
-    test<unsigned short>();
-    test<int>();
-    test<unsigned int>();
-    test<long>();
-    test<unsigned long>();
-    test<long long>();
-    test<unsigned long long>();
-    test<wchar_t>();
-#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
-    test<char16_t>();
-    test<char32_t>();
-#endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
-    test<int*>();
-    test<const int*>();
+    TestEachAtomicType<TestFn>()();
 }

test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_add.pass.cpp

 #include <type_traits>
 #include <cassert>
 
+#include "atomic_helpers.h"
+
 template <class T>
-void
-test()
-{
+struct TestFn {
+  void operator()() const {
     {
         typedef std::atomic<T> A;
         A t;

         assert(std::atomic_fetch_add(&t, T(2)) == T(1));
         assert(t == T(3));
     }
   }
+};
 
 template <class T>
-void
-testp()
+void testp()
 {
     {
         typedef std::atomic<T> A;

     }
 }
 
-struct A
-{
-    int i;
-
-    explicit A(int d = 0) noexcept {i=d;}
-    A(const A& a) : i(a.i) {}
-    A(const volatile A& a) : i(a.i) {}
-
-    void operator=(const volatile A& a) volatile {i = a.i;}
-
-    friend bool operator==(const A& x, const A& y)
-        {return x.i == y.i;}
-};
-
 int main()
 {
-    test<char>();
-    test<signed char>();
-    test<unsigned char>();
-    test<short>();
-    test<unsigned short>();
-    test<int>();
-    test<unsigned int>();
-    test<long>();
-    test<unsigned long>();
-    test<long long>();
-    test<unsigned long long>();
-    test<wchar_t>();
-#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
-    test<char16_t>();
-    test<char32_t>();
-#endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+    TestEachIntegralType<TestFn>()();
     testp<int*>();
     testp<const int*>();
 }

test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_add_explicit.pass.cpp

 #include <type_traits>
 #include <cassert>
 
+#include "atomic_helpers.h"
+
 template <class T>
-void
-test()
-{
+struct TestFn {
+  void operator()() const {
     {
         typedef std::atomic<T> A;
         A t;

                                             std::memory_order_seq_cst) == T(1));
         assert(t == T(3));
     }
   }
+};
 
 template <class T>
 void

     }
 }
 
-struct A
-{
-    int i;
-
-    explicit A(int d = 0) noexcept {i=d;}
-    A(const A& a) : i(a.i) {}
-    A(const volatile A& a) : i(a.i) {}
-
-    void operator=(const volatile A& a) volatile {i = a.i;}
-
-    friend bool operator==(const A& x, const A& y)
-        {return x.i == y.i;}
-};
-
 int main()
 {
-    test<char>();
-    test<signed char>();
-    test<unsigned char>();
-    test<short>();
-    test<unsigned short>();
-    test<int>();
-    test<unsigned int>();
-    test<long>();
-    test<unsigned long>();
-    test<long long>();
-    test<unsigned long long>();
-    test<wchar_t>();
-#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
-    test<char16_t>();
-    test<char32_t>();
-#endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+    TestEachIntegralType<TestFn>()();
     testp<int*>();
     testp<const int*>();
 }

test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_and.pass.cpp

 #include <type_traits>
 #include <cassert>
 
+#include "atomic_helpers.h"
+
 template <class T>
-void
-test()
-{
+struct TestFn {
+  void operator()() const {
     {
         typedef std::atomic<T> A;
         A t;

         assert(std::atomic_fetch_and(&t, T(2)) == T(3));
         assert(t == T(2));
     }
   }
+};
 
 int main()
 {
-    test<char>();
-    test<signed char>();
-    test<unsigned char>();
-    test<short>();
-    test<unsigned short>();
-    test<int>();
-    test<unsigned int>();
-    test<long>();
-    test<unsigned long>();
-    test<long long>();
-    test<unsigned long long>();
-    test<wchar_t>();
-#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
-    test<char16_t>();
-    test<char32_t>();
-#endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+    TestEachIntegralType<TestFn>()();
 }

test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_and_explicit.pass.cpp

 #include <type_traits>
 #include <cassert>
 
+#include "atomic_helpers.h"
+
 template <class T>
-void
-test()
-{
+struct TestFn {
+  void operator()() const {
     {
         typedef std::atomic<T> A;
         A t;

                std::memory_order_seq_cst) == T(3));
         assert(t == T(2));
     }
   }
+};
 
 int main()
 {
-    test<char>();
-    test<signed char>();
-    test<unsigned char>();
-    test<short>();
-    test<unsigned short>();
-    test<int>();
-    test<unsigned int>();
-    test<long>();
-    test<unsigned long>();
-    test<long long>();
-    test<unsigned long long>();
-    test<wchar_t>();
-#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
-    test<char16_t>();
-    test<char32_t>();
-#endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+    TestEachIntegralType<TestFn>()();
 }

test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_or.pass.cpp

 #include <type_traits>
 #include <cassert>
 
+#include "atomic_helpers.h"
+
 template <class T>
-void
-test()
-{
+struct TestFn {
+  void operator()() const {
     {
         typedef std::atomic<T> A;
         A t;

         assert(std::atomic_fetch_or(&t, T(2)) == T(3));
         assert(t == T(3));
     }
   }
+};
 
 int main()
 {
-    test<char>();
-    test<signed char>();
-    test<unsigned char>();
-    test<short>();
-    test<unsigned short>();
-    test<int>();
-    test<unsigned int>();
-    test<long>();
-    test<unsigned long>();
-    test<long long>();
-    test<unsigned long long>();
-    test<wchar_t>();
-#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
-    test<char16_t>();
-    test<char32_t>();
-#endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+    TestEachIntegralType<TestFn>()();
 }

test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_or_explicit.pass.cpp

 #include <type_traits>
 #include <cassert>
 
+#include "atomic_helpers.h"
+
 template <class T>
-void
-test()
-{
+struct TestFn {
+  void operator()() const {
     {
         typedef std::atomic<T> A;
         A t;

                std::memory_order_seq_cst) == T(3));
         assert(t == T(3));
     }
   }
+};
 
 int main()
 {
-    test<char>();
-    test<signed char>();
-    test<unsigned char>();
-    test<short>();
-    test<unsigned short>();
-    test<int>();
-    test<unsigned int>();
-    test<long>();
-    test<unsigned long>();
-    test<long long>();
-    test<unsigned long long>();
-    test<wchar_t>();
-#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
-    test<char16_t>();
-    test<char32_t>();
-#endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+    TestEachIntegralType<TestFn>()();
 }

test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_sub.pass.cpp

 #include <type_traits>
 #include <cassert>
 
+#include "atomic_helpers.h"
+
 template <class T>
-void
-test()
-{
+struct TestFn {
+  void operator()() const {
     {
         typedef std::atomic<T> A;
         A t;

         assert(std::atomic_fetch_sub(&t, T(2)) == T(3));
         assert(t == T(1));
     }
   }
+};
 
 template <class T>
-void
-testp()
+void testp()
 {
     {
         typedef std::atomic<T> A;

     }
 }
 
-struct A
-{
-    int i;
-
-    explicit A(int d = 0) noexcept {i=d;}
-    A(const A& a) : i(a.i) {}
-    A(const volatile A& a) : i(a.i) {}
-
-    void operator=(const volatile A& a) volatile {i = a.i;}
-
-    friend bool operator==(const A& x, const A& y)
-        {return x.i == y.i;}
-};
-
 int main()
 {
-    test<char>();
-    test<signed char>();
-    test<unsigned char>();
-    test<short>();
-    test<unsigned short>();
-    test<int>();
-    test<unsigned int>();
-    test<long>();
-    test<unsigned long>();
-    test<long long>();
-    test<unsigned long long>();
-    test<wchar_t>();
-#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
-    test<char16_t>();
-    test<char32_t>();
-#endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+    TestEachIntegralType<TestFn>()();
     testp<int*>();
     testp<const int*>();
 }

test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_sub_explicit.pass.cpp

 #include <type_traits>
 #include <cassert>
 
+#include "atomic_helpers.h"
+
 template <class T>
-void
-test()
-{
+struct TestFn {
+  void operator()() const {
     {
         typedef std::atomic<T> A;
         A t;

                                             std::memory_order_seq_cst) == T(3));
         assert(t == T(1));
     }
   }
+};
 
 template <class T>
-void
-testp()
+void testp()
 {
     {
         typedef std::atomic<T> A;

     }
 }
 
-struct A
-{
-    int i;
-
-    explicit A(int d = 0) noexcept {i=d;}
-    A(const A& a) : i(a.i) {}
-    A(const volatile A& a) : i(a.i) {}
-
-    void operator=(const volatile A& a) volatile {i = a.i;}
-
-    friend bool operator==(const A& x, const A& y)
-        {return x.i == y.i;}
-};
-
 int main()
 {
-    test<char>();
-    test<signed char>();
-    test<unsigned char>();
-    test<short>();
-    test<unsigned short>();
-    test<int>();
-    test<unsigned int>();
-    test<long>();
-    test<unsigned long>();
-    test<long long>();
-    test<unsigned long long>();
-    test<wchar_t>();
-#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
-    test<char16_t>();
-    test<char32_t>();
-#endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+    TestEachIntegralType<TestFn>()();
     testp<int*>();
     testp<const int*>();
 }

test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_xor.pass.cpp

 #include <type_traits>
 #include <cassert>
 
+#include "atomic_helpers.h"
+
 template <class T>
-void
-test()
-{
+struct TestFn {
+  void operator()() const {
     {
         typedef std::atomic<T> A;
         A t;

         assert(std::atomic_fetch_xor(&t, T(2)) == T(3));
         assert(t == T(1));
     }
   }
+};
 
 int main()
 {
-    test<char>();
-    test<signed char>();
-    test<unsigned char>();
-    test<short>();
-    test<unsigned short>();
-    test<int>();
-    test<unsigned int>();
-    test<long>();
-    test<unsigned long>();
-    test<long long>();
-    test<unsigned long long>();
-    test<wchar_t>();
-#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
-    test<char16_t>();
-    test<char32_t>();
-#endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+    TestEachIntegralType<TestFn>()();
 }

test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_xor_explicit.pass.cpp

 #include <type_traits>
 #include <cassert>
 
+#include "atomic_helpers.h"
+
 template <class T>
-void
-test()
-{
+struct TestFn {
+  void operator()() const {
     {
         typedef std::atomic<T> A;
         A t;

                std::memory_order_seq_cst) == T(3));
         assert(t == T(1));
     }
   }
+};
 
 int main()
 {
-    test<char>();
-    test<signed char>();
-    test<unsigned char>();
-    test<short>();
-    test<unsigned short>();
-    test<int>();
-    test<unsigned int>();
-    test<long>();
-    test<unsigned long>();
-    test<long long>();
-    test<unsigned long long>();
-    test<wchar_t>();
-#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
-    test<char16_t>();
-    test<char32_t>();
-#endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
+    TestEachIntegralType<TestFn>()();
 }

test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_helpers.h

+#ifndef ATOMIC_HELPERS_H
+#define ATOMIC_HELPERS_H
+
+#include <cassert>
+
+#include "test_macros.h"
+
+struct UserAtomicType
+{
+    int i;
+
+    explicit UserAtomicType(int d = 0) TEST_NOEXCEPT : i(d) {}
+
+    friend bool operator==(const UserAtomicType& x, const UserAtomicType& y)
+    { return x.i == y.i; }
+};
+
+template < template <class TestArg> class TestFunctor > 
+struct TestEachIntegralType {
+    void operator()() const {
+        TestFunctor<char>()(); 
+        TestFunctor<signed char>()();
+        TestFunctor<unsigned char>()();
+        TestFunctor<short>()();
+        TestFunctor<unsigned short>()();
+        TestFunctor<int>()();
+        TestFunctor<unsigned int>()();
+        TestFunctor<long>()();
+        TestFunctor<unsigned long>()();
+        TestFunctor<long long>()();
+        TestFunctor<unsigned long long>()();
+        TestFunctor<wchar_t>();
+#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
+        TestFunctor<char16_t>()();
+        TestFunctor<char32_t>()();
+#endif
+    }
+};
+
+template < template <class TestArg> class TestFunctor > 
+struct TestEachAtomicType {
+    void operator()() const {
+        TestEachIntegralType<TestFunctor>()();
+        TestFunctor<UserAtomicType>()();
+        TestFunctor<int*>()();
+        TestFunctor<const int*>()();
+    }
+};
+
+
+#endif // ATOMIC_HELPER_H

test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_init.pass.cpp

 //===----------------------------------------------------------------------===//
 //
 // UNSUPPORTED: libcpp-has-no-threads
-//  ... assertion fails line 34
+//  ... assertion fails line 36
 
 // <atomic>
 

 #include <type_traits>
 #include <cassert>
 
+#include "atomic_helpers.h"
+
 template <class T>
-void
-test()
-{
+struct TestFn {
+  void operator()() const {
     typedef std::atomic<T> A;
     A t;
     std::atomic_init(&t, T(1));

     volatile A vt;
     std::atomic_init(&vt, T(2));
     assert(vt == T(2));
   }
-
-struct A
-{
-    int i;
-
-    explicit A(int d = 0) noexcept {i=d;}
-
-    friend bool operator==(const A& x, const A& y)
-        {return x.i == y.i;}
 };
 
 int main()
 {
-    test<A>();
-    test<char>();
-    test<signed char>();
-    test<unsigned char>();
-    test<short>();
-    test<unsigned short>();
-    test<int>();
-    test<unsigned int>();
-    test<long>();
-    test<unsigned long>();
-    test<long long>();
-    test<unsigned long long>();
-    test<wchar_t>();
-#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
-    test<char16_t>();
-    test<char32_t>();
-#endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
-    test<int*>();
-    test<const int*>();
+    TestEachAtomicType<TestFn>()();
 }

test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_is_lock_free.pass.cpp

 #include <atomic>
 #include <cassert>
 
+#include "atomic_helpers.h"
+
 template <class T>
-void
-test()
-{
+struct TestFn {
+  void operator()() const {
     typedef std::atomic<T> A;
     A t;
     bool b1 = std::atomic_is_lock_free(static_cast<const A*>(&t));
     volatile A vt;
     bool b2 = std::atomic_is_lock_free(static_cast<const volatile A*>(&vt));
     assert(b1 == b2);
   }
+};
 
 struct A
 {

 
 int main()
 {
-    test<A>();
-    test<char>();
-    test<signed char>();
-    test<unsigned char>();
-    test<short>();
-    test<unsigned short>();
-    test<int>();
-    test<unsigned int>();
-    test<long>();
-    test<unsigned long>();
-    test<long long>();
-    test<unsigned long long>();
-    test<wchar_t>();
-#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
-    test<char16_t>();
-    test<char32_t>();
-#endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
-    test<int*>();
-    test<const int*>();
+    TestFn<A>()();
+    TestEachAtomicType<TestFn>()();
 }

test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_load.pass.cpp

 //===----------------------------------------------------------------------===//
 //
 // UNSUPPORTED: libcpp-has-no-threads
-//  ... assertion fails line 34
+//  ... assertion fails line 35
 
 // <atomic>
 

 #include <type_traits>
 #include <cassert>
 
+#include "atomic_helpers.h"
+
 template <class T>
-void
-test()
-{
+struct TestFn {
+  void operator()() const {
     typedef std::atomic<T> A;
     A t;
     std::atomic_init(&t, T(1));

     volatile A vt;
     std::atomic_init(&vt, T(2));
     assert(std::atomic_load(&vt) == T(2));
   }
-
-struct A
-{
-    int i;
-
-    explicit A(int d = 0) noexcept {i=d;}
-
-    friend bool operator==(const A& x, const A& y)
-        {return x.i == y.i;}
 };
 
 int main()
 {
-    test<A>();
-    test<char>();
-    test<signed char>();
-    test<unsigned char>();
-    test<short>();
-    test<unsigned short>();
-    test<int>();
-    test<unsigned int>();
-    test<long>();
-    test<unsigned long>();
-    test<long long>();
-    test<unsigned long long>();
-    test<wchar_t>();
-#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
-    test<char16_t>();
-    test<char32_t>();
-#endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
-    test<int*>();
-    test<const int*>();
+    TestEachAtomicType<TestFn>()();
 }

test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_load_explicit.pass.cpp

 #include <type_traits>
 #include <cassert>
 
+#include "atomic_helpers.h"
+
 template <class T>
-void
-test()
-{
+struct TestFn {
+  void operator()() const {
     typedef std::atomic<T> A;
     A t;
     std::atomic_init(&t, T(1));

     volatile A vt;
     std::atomic_init(&vt, T(2));
     assert(std::atomic_load_explicit(&vt, std::memory_order_seq_cst) == T(2));
   }
-
-struct A
-{
-    int i;
-
-    explicit A(int d = 0) noexcept {i=d;}
-
-    friend bool operator==(const A& x, const A& y)
-        {return x.i == y.i;}
 };
 
 int main()
 {
-    test<A>();
-    test<char>();
-    test<signed char>();
-    test<unsigned char>();
-    test<short>();
-    test<unsigned short>();
-    test<int>();
-    test<unsigned int>();
-    test<long>();
-    test<unsigned long>();
-    test<long long>();
-    test<unsigned long long>();
-    test<wchar_t>();
-#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
-    test<char16_t>();
-    test<char32_t>();
-#endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
-    test<int*>();
-    test<const int*>();
+    TestEachAtomicType<TestFn>()();
 }

test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_store.pass.cpp

 //===----------------------------------------------------------------------===//
 //
 // UNSUPPORTED: libcpp-has-no-threads
-//  ... assertion fails line 31
 
 // <atomic>
 

 #include <type_traits>
 #include <cassert>
 
+#include "atomic_helpers.h"
+
 template <class T>
-void
-test()
-{
+struct TestFn {
+  void operator()() const {
     typedef std::atomic<T> A;
     A t;
     std::atomic_store(&t, T(1));

     volatile A vt;
     std::atomic_store(&vt, T(2));
     assert(vt == T(2));
   }
-
-struct A
-{
-    int i;
-
-    explicit A(int d = 0) noexcept {i=d;}
-
-    friend bool operator==(const A& x, const A& y)
-        {return x.i == y.i;}
 };
 
+
 int main()
 {
-    test<A>();
-    test<char>();
-    test<signed char>();
-    test<unsigned char>();
-    test<short>();
-    test<unsigned short>();
-    test<int>();
-    test<unsigned int>();
-    test<long>();
-    test<unsigned long>();
-    test<long long>();
-    test<unsigned long long>();
-    test<wchar_t>();
-#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
-    test<char16_t>();
-    test<char32_t>();
-#endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
-    test<int*>();
-    test<const int*>();
+    TestEachAtomicType<TestFn>()();
 }

test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_store_explicit.pass.cpp

 //===----------------------------------------------------------------------===//
 //
 // UNSUPPORTED: libcpp-has-no-threads
-//  ... assertion fails line 31
 
 // <atomic>
 

 #include <type_traits>
 #include <cassert>
 
+#include "atomic_helpers.h"
+
 template <class T>
-void
-test()
-{
+struct TestFn {
+  void operator()() const {
     typedef std::atomic<T> A;
     A t;
     std::atomic_store_explicit(&t, T(1), std::memory_order_seq_cst);

     volatile A vt;
     std::atomic_store_explicit(&vt, T(2), std::memory_order_seq_cst);
     assert(vt == T(2));
   }
-
-struct A
-{
-    int i;
-
-    explicit A(int d = 0) noexcept {i=d;}
-
-    friend bool operator==(const A& x, const A& y)
-        {return x.i == y.i;}
 };
 
+
 int main()
 {
-    test<A>();
-    test<char>();
-    test<signed char>();
-    test<unsigned char>();
-    test<short>();
-    test<unsigned short>();
-    test<int>();
-    test<unsigned int>();
-    test<long>();
-    test<unsigned long>();
-    test<long long>();
-    test<unsigned long long>();
-    test<wchar_t>();
-#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
-    test<char16_t>();
-    test<char32_t>();
-#endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
-    test<int*>();
-    test<const int*>();
+    TestEachAtomicType<TestFn>()();
 }

test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_var_init.pass.cpp

 //===----------------------------------------------------------------------===//
 //
 // UNSUPPORTED: libcpp-has-no-threads
+// XFAIL: c++98, c++03
 
 // <atomic>
 

test/std/atomics/atomics.types.operations/atomics.types.operations.req/ctor.pass.cpp

 #include <type_traits>
 #include <cassert>
 
+#include "atomic_helpers.h"
+
 struct UserType {
     int i;
 

 };
 
 template <class Tp>
-void test() {
-    typedef std::atomic<Tp> Atomic;
-    static_assert(std::is_literal_type<Atomic>::value, "");
-    constexpr Tp t(42);
-    {
-        constexpr Atomic a(t);
-        assert(a == t);
-    }
-    {
-        constexpr Atomic a{t};
-        assert(a == t);
-    }
-    {
-        constexpr Atomic a = ATOMIC_VAR_INIT(t);
-        assert(a == t);
+struct TestFunc {
+    void operator()() const {
+        typedef std::atomic<Tp> Atomic;
+        static_assert(std::is_literal_type<Atomic>::value, "");
+        constexpr Tp t(42);
+        {
+            constexpr Atomic a(t);
+            assert(a == t);
+        }
+        {
+            constexpr Atomic a{t};
+            assert(a == t);
+        }
+        {
+            constexpr Atomic a = ATOMIC_VAR_INIT(t);
+            assert(a == t);
+        }
     }
-}
+};
 
 
 int main()
 {
-    test<int>();
-    test<UserType>();
+    TestFunc<UserType>()();
+    TestEachIntegralType<TestFunc>()();
 }

test/support/test_macros.h

 #endif
 
 #if TEST_STD_VER >= 11
+#define TEST_CONSTEXPR constexpr
 #define TEST_NOEXCEPT noexcept
 #else
+#define TEST_CONSTEXPR
 #define TEST_NOEXCEPT
 #endif