[libc++] Remove workarounds for missing __builtin_addressof

[ldionne]

Summary

All supported compilers implement builtin_addressof. Even MSVC implements
addressof as a simple call to builtin_addressof, so it would work if we
were to port libc++ to that compiler.

[• Quuxplusone]

LGTM if buildkite's happy.

libcxx/include/__config

 #endif
 
 #if __has_attribute(require_constant_initialization)
 #  define _LIBCPP_SAFE_STATIC __attribute__((__require_constant_initialization__))
 #else
 #  define _LIBCPP_SAFE_STATIC
 #endif
 
-#if !__has_builtin(__builtin_addressof) && _GNUC_VER < 700
-#define _LIBCPP_HAS_NO_BUILTIN_ADDRESSOF
-#endif
-
 #if __has_attribute(diagnose_if) && !defined(_LIBCPP_DISABLE_ADDITIONAL_DIAGNOSTICS)
 #  define _LIBCPP_DIAGNOSE_WARNING(...) \
      __attribute__((diagnose_if(__VA_ARGS__, "warning")))
 #  define _LIBCPP_DIAGNOSE_ERROR(...) \
      __attribute__((diagnose_if(__VA_ARGS__, "error")))
 #else
 #  define _LIBCPP_DIAGNOSE_WARNING(...)
 #  define _LIBCPP_DIAGNOSE_ERROR(...)

libcxx/include/__memory/addressof.h

 #pragma GCC system_header
 #endif
 
 _LIBCPP_PUSH_MACROS
 #include <__undef_macros>
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#ifndef _LIBCPP_HAS_NO_BUILTIN_ADDRESSOF
-
 template <class _Tp>
 inline _LIBCPP_CONSTEXPR_AFTER_CXX14
 _LIBCPP_NO_CFI _LIBCPP_INLINE_VISIBILITY
 _Tp*
 addressof(_Tp& __x) _NOEXCEPT
 {
     return __builtin_addressof(__x);
 }
 
-#else
-
-template <class _Tp>
-inline _LIBCPP_NO_CFI _LIBCPP_INLINE_VISIBILITY
-_Tp*
-addressof(_Tp& __x) _NOEXCEPT
-{
-  return reinterpret_cast<_Tp *>(
-      const_cast<char *>(&reinterpret_cast<const volatile char &>(__x)));
-}
-
-#endif // _LIBCPP_HAS_NO_BUILTIN_ADDRESSOF
-
 #if defined(_LIBCPP_HAS_OBJC_ARC) && !defined(_LIBCPP_PREDEFINED_OBJC_ARC_ADDRESSOF)
 // Objective-C++ Automatic Reference Counting uses qualified pointers
 // that require special addressof() signatures. When
 // _LIBCPP_PREDEFINED_OBJC_ARC_ADDRESSOF is defined, the compiler
 // itself is providing these definitions. Otherwise, we provide them.
 template <class _Tp>
 inline _LIBCPP_INLINE_VISIBILITY
 __strong _Tp*

libcxx/include/optional

public:
     }
 
     _LIBCPP_INLINE_VISIBILITY
     constexpr
     add_pointer_t<value_type const>
     operator->() const
     {
         _LIBCPP_ASSERT(this->has_value(), "optional operator-> called on a disengaged value");
-#ifndef _LIBCPP_HAS_NO_BUILTIN_ADDRESSOF
         return _VSTD::addressof(this->__get());
-#else
-        return __operator_arrow(__has_operator_addressof<value_type>{}, this->__get());
-#endif
     }
 
     _LIBCPP_INLINE_VISIBILITY
     constexpr
     add_pointer_t<value_type>
     operator->()
     {
         _LIBCPP_ASSERT(this->has_value(), "optional operator-> called on a disengaged value");
-#ifndef _LIBCPP_HAS_NO_BUILTIN_ADDRESSOF
         return _VSTD::addressof(this->__get());
-#else
-        return __operator_arrow(__has_operator_addressof<value_type>{}, this->__get());
-#endif
     }
 
     _LIBCPP_INLINE_VISIBILITY
     constexpr
     const value_type&
     operator*() const& noexcept
     {
         _LIBCPP_ASSERT(this->has_value(), "optional operator* called on a disengaged value");
constexpr value_type value_or(_Up&& __v) &&
                       "optional<T>::value_or: T must be move constructible");
         static_assert(is_convertible_v<_Up, value_type>,
                       "optional<T>::value_or: U must be convertible to T");
         return this->has_value() ? _VSTD::move(this->__get()) :
                                   static_cast<value_type>(_VSTD::forward<_Up>(__v));
     }
 
     using __base::reset;
-
-private:
-    template <class _Up>
-    _LIBCPP_INLINE_VISIBILITY
-    static _LIBCPP_CONSTEXPR_AFTER_CXX17 _Up*
-    __operator_arrow(true_type, _Up& __x)
-    {
-        return _VSTD::addressof(__x);
-    }
-
-    template <class _Up>
-    _LIBCPP_INLINE_VISIBILITY
-    static constexpr _Up*
-    __operator_arrow(false_type, _Up& __x)
-    {
-        return &__x;
-    }
 };
 
 #ifndef _LIBCPP_HAS_NO_DEDUCTION_GUIDES
 template<class T>
     optional(T) -> optional<T>;
 #endif
 
 // Comparisons between optionals

libcxx/include/type_traits

 __uint128_t __convert_to_integral(__uint128_t __val) { return __val; }
 #endif
 
 template <class _Tp>
 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
 typename __sfinae_underlying_type<_Tp>::__promoted_type
 __convert_to_integral(_Tp __val) { return __val; }
 
-#ifndef _LIBCPP_CXX03_LANG
-
-template <class _Tp>
-struct __has_operator_addressof_member_imp
-{
-    template <class _Up>
-        static auto __test(int)
-            -> typename __select_2nd<decltype(declval<_Up>().operator&()), true_type>::type;
-    template <class>
-        static auto __test(long) -> false_type;
-
-    static const bool value = decltype(__test<_Tp>(0))::value;
-};
-
-template <class _Tp>
-struct __has_operator_addressof_free_imp
-{
-    template <class _Up>
-        static auto __test(int)
-            -> typename __select_2nd<decltype(operator&(declval<_Up>())), true_type>::type;
-    template <class>
-        static auto __test(long) -> false_type;
-
-    static const bool value = decltype(__test<_Tp>(0))::value;
-};
-
-template <class _Tp>
-struct __has_operator_addressof
-    : public integral_constant<bool, __has_operator_addressof_member_imp<_Tp>::value
-                                  || __has_operator_addressof_free_imp<_Tp>::value>
-{};
-
-#endif // _LIBCPP_CXX03_LANG
-
 // is_scoped_enum [meta.unary.prop]
 
 #if _LIBCPP_STD_VER > 20
 template <class _Tp, bool = is_enum_v<_Tp> >
 struct __is_scoped_enum_helper : false_type {};
 
 template <class _Tp>
 struct __is_scoped_enum_helper<_Tp, true>

libcxx/include/version

 # define __cpp_lib_string_udls                          201304L
 # define __cpp_lib_transformation_trait_aliases         201304L
 # define __cpp_lib_transparent_operators                201210L
 # define __cpp_lib_tuple_element_t                      201402L
 # define __cpp_lib_tuples_by_type                       201304L
 #endif
 
 #if _LIBCPP_STD_VER > 14
-# if !defined(_LIBCPP_HAS_NO_BUILTIN_ADDRESSOF)
-#   define __cpp_lib_addressof_constexpr                201603L
-# endif
+# define __cpp_lib_addressof_constexpr                  201603L
 # define __cpp_lib_allocator_traits_is_always_equal     201411L
 # define __cpp_lib_any                                  201606L
 # define __cpp_lib_apply                                201603L
 # define __cpp_lib_array_constexpr                      201603L
 # define __cpp_lib_as_const                             201510L
 # if !defined(_LIBCPP_HAS_NO_THREADS)
 #   define __cpp_lib_atomic_is_always_lock_free         201603L
 # endif

libcxx/test/libcxx/utilities/meta/meta.unary/meta.unary.prop/__has_operator_addressof.pass.cpp

-//===----------------------------------------------------------------------===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-// UNSUPPORTED: c++03
-
-// type_traits
-
-// extension
-
-// template <typename _Tp> struct __has_operator_addressof
-
-
-#include <type_traits>
-
-#include "test_macros.h"
-
-
-struct A
-{
-};
-
-struct B
-{
-    constexpr B* operator&() const;
-};
-
-struct D;
-
-struct C
-{
-    template <class U>
-    D operator,(U&&);
-};
-
-struct E
-{
-    constexpr C operator&() const;
-};
-
-struct F {};
-constexpr F* operator&(F const &) { return nullptr; }
-
-struct G {};
-constexpr G* operator&(G &&) { return nullptr; }
-
-struct H {};
-constexpr H* operator&(H const &&) { return nullptr; }
-
-struct J
-{
-    constexpr J* operator&() const &&;
-};
-
-
-int main(int, char**)
-{
-    static_assert(std::__has_operator_addressof<int>::value == false, "");
-    static_assert(std::__has_operator_addressof<A>::value == false, "");
-    static_assert(std::__has_operator_addressof<B>::value == true, "");
-    static_assert(std::__has_operator_addressof<E>::value == true, "");
-    static_assert(std::__has_operator_addressof<F>::value == true, "");
-    static_assert(std::__has_operator_addressof<G>::value == true, "");
-    static_assert(std::__has_operator_addressof<H>::value == true, "");
-    static_assert(std::__has_operator_addressof<J>::value == true, "");
-
-  return 0;
-}

libcxx/test/std/language.support/support.limits/support.limits.general/memory.version.pass.cpp

 #   error "__cpp_lib_transparent_operators should be defined in c++14"
 # endif
 # if __cpp_lib_transparent_operators != 201210L
 #   error "__cpp_lib_transparent_operators should have the value 201210L in c++14"
 # endif
 
 #elif TEST_STD_VER == 17
 
-# if TEST_HAS_BUILTIN(__builtin_addressof) || TEST_GCC_VER >= 700
-#   ifndef __cpp_lib_addressof_constexpr
-#     error "__cpp_lib_addressof_constexpr should be defined in c++17"
-#   endif
-#   if __cpp_lib_addressof_constexpr != 201603L
-#     error "__cpp_lib_addressof_constexpr should have the value 201603L in c++17"
-#   endif
-# else
-#   ifdef __cpp_lib_addressof_constexpr
-#     error "__cpp_lib_addressof_constexpr should not be defined when TEST_HAS_BUILTIN(__builtin_addressof) || TEST_GCC_VER >= 700 is not defined!"
-#   endif
-# endif
+# ifndef __cpp_lib_addressof_constexpr
+#   error "__cpp_lib_addressof_constexpr should be defined in c++17"
+# endif
+# if __cpp_lib_addressof_constexpr != 201603L
+#   error "__cpp_lib_addressof_constexpr should have the value 201603L in c++17"
+# endif
 
 # ifndef __cpp_lib_allocator_traits_is_always_equal
 #   error "__cpp_lib_allocator_traits_is_always_equal should be defined in c++17"
 # endif
 # if __cpp_lib_allocator_traits_is_always_equal != 201411L
 #   error "__cpp_lib_allocator_traits_is_always_equal should have the value 201411L in c++17"
 # endif
 

 #   error "__cpp_lib_transparent_operators should be defined in c++17"
 # endif
 # if __cpp_lib_transparent_operators != 201510L
 #   error "__cpp_lib_transparent_operators should have the value 201510L in c++17"
 # endif
 
 #elif TEST_STD_VER == 20
 
-# if TEST_HAS_BUILTIN(__builtin_addressof) || TEST_GCC_VER >= 700
-#   ifndef __cpp_lib_addressof_constexpr
-#     error "__cpp_lib_addressof_constexpr should be defined in c++20"
-#   endif
-#   if __cpp_lib_addressof_constexpr != 201603L
-#     error "__cpp_lib_addressof_constexpr should have the value 201603L in c++20"
-#   endif
-# else
-#   ifdef __cpp_lib_addressof_constexpr
-#     error "__cpp_lib_addressof_constexpr should not be defined when TEST_HAS_BUILTIN(__builtin_addressof) || TEST_GCC_VER >= 700 is not defined!"
-#   endif
-# endif
+# ifndef __cpp_lib_addressof_constexpr
+#   error "__cpp_lib_addressof_constexpr should be defined in c++20"
+# endif
+# if __cpp_lib_addressof_constexpr != 201603L
+#   error "__cpp_lib_addressof_constexpr should have the value 201603L in c++20"
+# endif
 
 # ifndef __cpp_lib_allocator_traits_is_always_equal
 #   error "__cpp_lib_allocator_traits_is_always_equal should be defined in c++20"
 # endif
 # if __cpp_lib_allocator_traits_is_always_equal != 201411L
 #   error "__cpp_lib_allocator_traits_is_always_equal should have the value 201411L in c++20"
 # endif
 

 #   error "__cpp_lib_transparent_operators should be defined in c++20"
 # endif
 # if __cpp_lib_transparent_operators != 201510L
 #   error "__cpp_lib_transparent_operators should have the value 201510L in c++20"
 # endif
 
 #elif TEST_STD_VER > 20
 
-# if TEST_HAS_BUILTIN(__builtin_addressof) || TEST_GCC_VER >= 700
-#   ifndef __cpp_lib_addressof_constexpr
-#     error "__cpp_lib_addressof_constexpr should be defined in c++2b"
-#   endif
-#   if __cpp_lib_addressof_constexpr != 201603L
-#     error "__cpp_lib_addressof_constexpr should have the value 201603L in c++2b"
-#   endif
-# else
-#   ifdef __cpp_lib_addressof_constexpr
-#     error "__cpp_lib_addressof_constexpr should not be defined when TEST_HAS_BUILTIN(__builtin_addressof) || TEST_GCC_VER >= 700 is not defined!"
-#   endif
-# endif
+# ifndef __cpp_lib_addressof_constexpr
+#   error "__cpp_lib_addressof_constexpr should be defined in c++2b"
+# endif
+# if __cpp_lib_addressof_constexpr != 201603L
+#   error "__cpp_lib_addressof_constexpr should have the value 201603L in c++2b"
+# endif
 
 # ifndef __cpp_lib_allocator_traits_is_always_equal
 #   error "__cpp_lib_allocator_traits_is_always_equal should be defined in c++2b"
 # endif
 # if __cpp_lib_allocator_traits_is_always_equal != 201411L
 #   error "__cpp_lib_allocator_traits_is_always_equal should have the value 201411L in c++2b"
 # endif
 

libcxx/test/std/language.support/support.limits/support.limits.general/version.version.pass.cpp

 # endif
 
 # ifdef __cpp_lib_void_t
 #   error "__cpp_lib_void_t should not be defined before c++17"
 # endif
 
 #elif TEST_STD_VER == 17
 
-# if TEST_HAS_BUILTIN(__builtin_addressof) || TEST_GCC_VER >= 700
-#   ifndef __cpp_lib_addressof_constexpr
-#     error "__cpp_lib_addressof_constexpr should be defined in c++17"
-#   endif
-#   if __cpp_lib_addressof_constexpr != 201603L
-#     error "__cpp_lib_addressof_constexpr should have the value 201603L in c++17"
-#   endif
-# else
-#   ifdef __cpp_lib_addressof_constexpr
-#     error "__cpp_lib_addressof_constexpr should not be defined when TEST_HAS_BUILTIN(__builtin_addressof) || TEST_GCC_VER >= 700 is not defined!"
-#   endif
-# endif
+# ifndef __cpp_lib_addressof_constexpr
+#   error "__cpp_lib_addressof_constexpr should be defined in c++17"
+# endif
+# if __cpp_lib_addressof_constexpr != 201603L
+#   error "__cpp_lib_addressof_constexpr should have the value 201603L in c++17"
+# endif
 
 # ifndef __cpp_lib_allocator_traits_is_always_equal
 #   error "__cpp_lib_allocator_traits_is_always_equal should be defined in c++17"
 # endif
 # if __cpp_lib_allocator_traits_is_always_equal != 201411L
 #   error "__cpp_lib_allocator_traits_is_always_equal should have the value 201411L in c++17"
 # endif
 

 #   error "__cpp_lib_void_t should be defined in c++17"
 # endif
 # if __cpp_lib_void_t != 201411L
 #   error "__cpp_lib_void_t should have the value 201411L in c++17"
 # endif
 
 #elif TEST_STD_VER == 20
 
-# if TEST_HAS_BUILTIN(__builtin_addressof) || TEST_GCC_VER >= 700
-#   ifndef __cpp_lib_addressof_constexpr
-#     error "__cpp_lib_addressof_constexpr should be defined in c++20"
-#   endif
-#   if __cpp_lib_addressof_constexpr != 201603L
-#     error "__cpp_lib_addressof_constexpr should have the value 201603L in c++20"
-#   endif
-# else
-#   ifdef __cpp_lib_addressof_constexpr
-#     error "__cpp_lib_addressof_constexpr should not be defined when TEST_HAS_BUILTIN(__builtin_addressof) || TEST_GCC_VER >= 700 is not defined!"
-#   endif
-# endif
+# ifndef __cpp_lib_addressof_constexpr
+#   error "__cpp_lib_addressof_constexpr should be defined in c++20"
+# endif
+# if __cpp_lib_addressof_constexpr != 201603L
+#   error "__cpp_lib_addressof_constexpr should have the value 201603L in c++20"
+# endif
 
 # ifndef __cpp_lib_allocator_traits_is_always_equal
 #   error "__cpp_lib_allocator_traits_is_always_equal should be defined in c++20"
 # endif
 # if __cpp_lib_allocator_traits_is_always_equal != 201411L
 #   error "__cpp_lib_allocator_traits_is_always_equal should have the value 201411L in c++20"
 # endif
 

 #   error "__cpp_lib_void_t should be defined in c++20"
 # endif
 # if __cpp_lib_void_t != 201411L
 #   error "__cpp_lib_void_t should have the value 201411L in c++20"
 # endif
 
 #elif TEST_STD_VER > 20
 
-# if TEST_HAS_BUILTIN(__builtin_addressof) || TEST_GCC_VER >= 700
-#   ifndef __cpp_lib_addressof_constexpr
-#     error "__cpp_lib_addressof_constexpr should be defined in c++2b"
-#   endif
-#   if __cpp_lib_addressof_constexpr != 201603L
-#     error "__cpp_lib_addressof_constexpr should have the value 201603L in c++2b"
-#   endif
-# else
-#   ifdef __cpp_lib_addressof_constexpr
-#     error "__cpp_lib_addressof_constexpr should not be defined when TEST_HAS_BUILTIN(__builtin_addressof) || TEST_GCC_VER >= 700 is not defined!"
-#   endif
-# endif
+# ifndef __cpp_lib_addressof_constexpr
+#   error "__cpp_lib_addressof_constexpr should be defined in c++2b"
+# endif
+# if __cpp_lib_addressof_constexpr != 201603L
+#   error "__cpp_lib_addressof_constexpr should have the value 201603L in c++2b"
+# endif
 
 # ifndef __cpp_lib_allocator_traits_is_always_equal
 #   error "__cpp_lib_allocator_traits_is_always_equal should be defined in c++2b"
 # endif
 # if __cpp_lib_allocator_traits_is_always_equal != 201411L
 #   error "__cpp_lib_allocator_traits_is_always_equal should have the value 201411L in c++2b"
 # endif
 

libcxx/utils/generate_feature_test_macro_components.py

 #                   you've fully implemented the feature, you should remove
 #                   this field.
 # ================  ============================================================
 feature_test_macros = [ add_version_header(x) for x in [
   {
     "name": "__cpp_lib_addressof_constexpr",
     "values": { "c++17": 201603 },
     "headers": ["memory"],
-    "test_suite_guard": "TEST_HAS_BUILTIN(__builtin_addressof) || TEST_GCC_VER >= 700",
-    "libcxx_guard": "!defined(_LIBCPP_HAS_NO_BUILTIN_ADDRESSOF)",
   }, {
     "name": "__cpp_lib_allocator_traits_is_always_equal",
     "values": { "c++17": 201411 },
     "headers": ["deque", "forward_list", "list", "map", "memory", "scoped_allocator", "set", "string", "unordered_map", "unordered_set", "vector"],
   }, {
     "name": "__cpp_lib_any",
     "values": { "c++17": 201606 },
     "headers": ["any"],