Rename and rework `_LIBCPP_TRIVIAL_PAIR_COPY_CTOR`. Move FreeBSD configuration in-tree.

This patch does the following:

* It renames `_LIBCPP_TRIVIAL_PAIR_COPY_CTOR` to `_LIBCPP_DEPRECATED_ABI_DISABLE_PAIR_TRIVIAL_COPY_CTOR`.
* It automatically enables this option on FreeBSD in ABI V1, since that's the current ABI FreeBSD ships.
* It cleans up the handling of this option in `std::pair`.

I would like the sign off from the FreeBSD maintainers. They will no longer need to keep their `__config` changes downstream.

I'm still hoping to come up with a better way to maintain the ABI without needing these constructors.

Reviewed in https://reviews.llvm.org/D21329

llvm-svn: 275749

libcxx/include/__config

@@ -44,6 +44,17 @@
 #define _LIBCPP_ABI_FORWARD_LIST_REMOVE_NODE_POINTER_UB
 #define _LIBCPP_ABI_FIX_UNORDERED_CONTAINER_SIZE_TYPE
 #define _LIBCPP_ABI_VARIADIC_LOCK_GUARD
+#elif _LIBCPP_ABI_VERSION == 1
+// Feature macros for disabling pre ABI v1 features. All of these options
+// are deprecated.
+#if defined(__FreeBSD__)
+#define _LIBCPP_DEPRECATED_ABI_DISABLE_PAIR_TRIVIAL_COPY_CTOR
+#endif
+#endif
+
+#ifdef _LIBCPP_TRIVIAL_PAIR_COPY_CTOR
+#error "_LIBCPP_TRIVIAL_PAIR_COPY_CTOR" is no longer supported. \
+       use _LIBCPP_DEPRECATED_ABI_DISABLE_PAIR_TRIVIAL_COPY_CTOR instead
 #endif
 
 #define _LIBCPP_CONCAT1(_LIBCPP_X,_LIBCPP_Y) _LIBCPP_X##_LIBCPP_Y
@@ -746,10 +757,6 @@ template <unsigned> struct __static_assert_check {};
 #define _LIBCPP_WCTYPE_IS_MASK
 #endif
 
-#ifndef _LIBCPP_TRIVIAL_PAIR_COPY_CTOR
-#  define _LIBCPP_TRIVIAL_PAIR_COPY_CTOR 1
-#endif
-
 #ifndef _LIBCPP_STD_VER
 #  if  __cplusplus <= 201103L
 #    define _LIBCPP_STD_VER 11

libcxx/include/utility

@@ -285,9 +285,6 @@ struct _LIBCPP_TYPE_VIS_ONLY pair
     _T1 first;
     _T2 second;
 
-    // pair(const pair&) = default;
-    // pair(pair&&) = default;
-
 #ifndef _LIBCPP_HAS_NO_DEFAULT_FUNCTION_TEMPLATE_ARGS
     template <bool _Dummy = true, class = typename enable_if<
         __dependent_type<is_default_constructible<_T1>, _Dummy>::value &&
@@ -310,10 +307,7 @@ struct _LIBCPP_TYPE_VIS_ONLY pair
                                       )
             : first(__p.first), second(__p.second) {}
 
-#if !defined(_LIBCPP_HAS_NO_DEFAULTED_FUNCTIONS) && _LIBCPP_TRIVIAL_PAIR_COPY_CTOR
-    _LIBCPP_INLINE_VISIBILITY
-    pair(const pair& __p) = default;
-#elif !defined(_LIBCPP_HAS_NO_RVALUE_REFERENCES) || !_LIBCPP_TRIVIAL_PAIR_COPY_CTOR
+#if defined(_LIBCPP_DEPRECATED_ABI_DISABLE_PAIR_TRIVIAL_COPY_CTOR)
     _LIBCPP_INLINE_VISIBILITY
     pair(const pair& __p)
         _NOEXCEPT_(is_nothrow_copy_constructible<first_type>::value &&
@@ -322,6 +316,21 @@ struct _LIBCPP_TYPE_VIS_ONLY pair
           second(__p.second)
     {
     }
+
+# ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    pair(pair&& __p) _NOEXCEPT_(is_nothrow_move_constructible<first_type>::value &&
+                                is_nothrow_move_constructible<second_type>::value)
+        : first(_VSTD::forward<first_type>(__p.first)),
+          second(_VSTD::forward<second_type>(__p.second))
+    {
+    }
+# endif
+#elif !defined(_LIBCPP_CXX03_LANG)
+    pair(pair const&) = default;
+    pair(pair&&) = default;
+#else
+  // Use the implicitly declared copy constructor in C++03
 #endif
 
     _LIBCPP_INLINE_VISIBILITY
@@ -353,19 +362,6 @@ struct _LIBCPP_TYPE_VIS_ONLY pair
             : first(_VSTD::forward<_U1>(__p.first)),
               second(_VSTD::forward<_U2>(__p.second)) {}
 
-#ifndef _LIBCPP_HAS_NO_DEFAULTED_FUNCTIONS
-    _LIBCPP_INLINE_VISIBILITY
-    pair(pair&& __p) = default;
-#else
-    _LIBCPP_INLINE_VISIBILITY
-    pair(pair&& __p) _NOEXCEPT_(is_nothrow_move_constructible<first_type>::value &&
-                                is_nothrow_move_constructible<second_type>::value)
-        : first(_VSTD::forward<first_type>(__p.first)),
-          second(_VSTD::forward<second_type>(__p.second))
-    {
-    }
-#endif
-
     _LIBCPP_INLINE_VISIBILITY
     pair&
     operator=(pair&& __p) _NOEXCEPT_(is_nothrow_move_assignable<first_type>::value &&

libcxx/test/libcxx/utilities/utility/pairs/pairs.pair/trivial_copy_move.pass.cpp

@@ -0,0 +1,55 @@
+//===----------------------------------------------------------------------===//
+//
+//                     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.
+//
+//===----------------------------------------------------------------------===//
+
+// <utility>
+
+// template <class T1, class T2> struct pair
+
+// Doesn't pass due to use of is_trivially_* trait.
+// XFAIL: gcc-4.9
+
+// Test that we properly provide the old non-trivial copy operations
+// when the ABI macro is defined.
+
+#define _LIBCPP_DEPRECATED_ABI_DISABLE_PAIR_TRIVIAL_COPY_CTOR
+#include <utility>
+#include <cassert>
+
+#include "test_macros.h"
+
+#if TEST_STD_VER >= 11
+struct Dummy {
+  Dummy(Dummy const&) = delete;
+  Dummy(Dummy &&) = default;
+};
+#endif
+
+int main()
+{
+    typedef std::pair<int, short> P;
+    {
+        static_assert(std::is_copy_constructible<P>::value, "");
+        static_assert(!std::is_trivially_copy_constructible<P>::value, "");
+    }
+#if TEST_STD_VER >= 11
+    {
+        static_assert(std::is_move_constructible<P>::value, "");
+        static_assert(!std::is_trivially_move_constructible<P>::value, "");
+    }
+    {
+        using P1 = std::pair<Dummy, int>;
+        // This line fails because the non-trivial constructors do not provide
+        // SFINAE.
+        // static_assert(!std::is_copy_constructible<P1>::value, "");
+        static_assert(!std::is_trivially_copy_constructible<P1>::value, "");
+        static_assert(std::is_move_constructible<P1>::value, "");
+        static_assert(!std::is_trivially_move_constructible<P1>::value, "");
+    }
+#endif
+}