From 17da0e624287b34997ec8cb2169ae44c1e4969a2 Mon Sep 17 00:00:00 2001
From: dim <dim@ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f>
Date: Fri, 24 Mar 2017 18:28:13 +0000
Subject: [PATCH] Pull in r283944 from upstream libc++ trunk (by Eric
 Fiselier):

  Fix std::pair on FreeBSD

  Summary:
  FreeBSD ships an old ABI for std::pair which requires that it have
  non-trivial copy/move constructors. Currently the non-trivial
  copy/move is achieved by providing explicit definitions of the
  constructors. This is problematic because it means the constructors
  don't SFINAE properly. In order to SFINAE copy/move constructors they
  have to be explicitly defaulted and hense non-trivial.

  This patch attempts to provide SFINAE'ing copy/move constructors for
  std::pair while still making them non-trivial. It does this by adding
  a base class with a non-trivial copy constructor and then allowing
  pair's constructors to be generated by the compiler. This also allows
  the constructors to be constexpr.

  Reviewers: emaste, theraven, rsmith, dim

  Subscribers: cfe-commits

  Differential Revision: https://reviews.llvm.org/D25389

This should fix building www/chromium 57.0.2987.110 on stable/10 and
stable/9 without having to use -D_LIBCPP_TRIVIAL_PAIR_COPY_CTOR=1 (which
changes the ABI).  Direct commit to stable/10 and stable/9, since head
already has libc++ 4.0, which includes this fix.


git-svn-id: svn://svn.freebsd.org/base/stable/9@315915 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
---
 contrib/libc++/include/utility | 45 +++++++++++++---------------------
 1 file changed, 17 insertions(+), 28 deletions(-)

diff --git a/contrib/libc++/include/utility b/contrib/libc++/include/utility
index 6f324dbd6..470b6dcda 100644
--- a/contrib/libc++/include/utility
+++ b/contrib/libc++/include/utility
@@ -244,8 +244,20 @@ extern const piecewise_construct_t piecewise_construct;// = piecewise_construct_
 constexpr piecewise_construct_t piecewise_construct = piecewise_construct_t();
 #endif
 
+#if !_LIBCPP_TRIVIAL_PAIR_COPY_CTOR
+struct __non_trivially_copyable_base {
+  _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+  __non_trivially_copyable_base() _NOEXCEPT {}
+  _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+  __non_trivially_copyable_base(__non_trivially_copyable_base const&) _NOEXCEPT {}
+};
+#endif
+
 template <class _T1, class _T2>
 struct _LIBCPP_TYPE_VIS_ONLY pair
+#if !_LIBCPP_TRIVIAL_PAIR_COPY_CTOR
+: private __non_trivially_copyable_base
+#endif
 {
     typedef _T1 first_type;
     typedef _T2 second_type;
@@ -253,9 +265,6 @@ struct _LIBCPP_TYPE_VIS_ONLY pair
     _T1 first;
     _T2 second;
 
-    // pair(const pair&) = default;
-    // pair(pair&&) = default;
-
     _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR pair() : first(), second() {}
 
     _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
@@ -272,18 +281,11 @@ 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
-    _LIBCPP_INLINE_VISIBILITY
-    pair(const pair& __p)
-        _NOEXCEPT_(is_nothrow_copy_constructible<first_type>::value &&
-                   is_nothrow_copy_constructible<second_type>::value)
-        : first(__p.first),
-          second(__p.second)
-    {
-    }
+#if !defined(_LIBCPP_HAS_NO_DEFAULTED_FUNCTIONS)
+    pair(pair const&) = default;
+    pair(pair&&) = default;
+#else
+  // Use the implicitly declared copy constructor in C++03
 #endif
 
     _LIBCPP_INLINE_VISIBILITY
@@ -315,19 +317,6 @@ 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 &&
-- 
2.45.0