[libc++] Complete the implementation of N4190

Fixes #37402

Reviewed By: ldionne

Spies: EricWF, avogelsgesang, libcxx-commits, arphaman

Differential Revision: https://reviews.llvm.org/D124346

Author: philnik777

libcxx/docs/ReleaseNotes.rst

@@ -43,8 +43,8 @@ Implemented Papers
 - P0674R1 (Support arrays in ``make_shared`` and ``allocate_shared``)
 - P0980R1 (Making ``std::string`` constexpr)
 - P2216R3 (std::format improvements)
-
-- Implemented P0174R2 (Deprecating Vestigial Library Parts in C++17)
+- P0174R2 (Deprecating Vestigial Library Parts in C++17)
+- N4190 (Removing auto_ptr, random_shuffle(), And Old <functional> Stuff)
 
 - Marked the following papers as "Complete" (note that some of those might have
   been implemented in a previous release but not marked as such):
@@ -152,6 +152,12 @@ API Changes
   or upgrade to C++11 or later. It is possible to re-enable ``std::function`` in C++03 by defining
   ``_LIBCPP_ENABLE_CXX03_FUNCTION``. This option it will be removed in LLVM 16.
 
+- ``unary_function`` and ``binary_function`` are no longer available in C++17 and C++20.
+  They can be re-enabled by defining ``_LIBCPP_ENABLE_CXX17_REMOVED_UNARY_BINARY_FUNCTION``.
+  They are also marked as ``[[deprecated]]`` in C++11 and later. To disable deprecation warnings
+  you have to define ``_LIBCPP_DISABLE_DEPRECATION_WARNINGS``. Note that this disables
+  all deprecation warnings.
+
 ABI Changes
 -----------
 

libcxx/docs/Status/Cxx17Papers.csv

@@ -2,7 +2,7 @@
 "`N3911 <https://wg21.link/n3911>`__","LWG","TransformationTrait Alias ``void_t``\ .","Urbana","|Complete|","3.6"
 "`N4089 <https://wg21.link/n4089>`__","LWG","Safe conversions in ``unique_ptr<T[]>``\ .","Urbana","|In Progress|","3.9"
 "`N4169 <https://wg21.link/n4169>`__","LWG","A proposal to add invoke function template","Urbana","|Complete|","3.7"
-"`N4190 <https://wg21.link/n4190>`__","LWG","Removing auto_ptr, random_shuffle(), And Old <functional> Stuff.","Urbana","|In Progress|",""
+"`N4190 <https://wg21.link/n4190>`__","LWG","Removing auto_ptr, random_shuffle(), And Old <functional> Stuff.","Urbana","|Complete|","15.0"
 "`N4258 <https://wg21.link/n4258>`__","LWG","Cleaning-up noexcept in the Library.","Urbana","|In Progress|","3.7"
 "`N4259 <https://wg21.link/n4259>`__","CWG","Wording for std::uncaught_exceptions","Urbana","|Complete|","3.7"
 "`N4277 <https://wg21.link/n4277>`__","LWG","TriviallyCopyable ``reference_wrapper``\ .","Urbana","|Complete|","3.2"

libcxx/include/__config

@@ -83,9 +83,6 @@
 #    define _LIBCPP_ABI_BAD_FUNCTION_CALL_GOOD_WHAT_MESSAGE
 // Enable optimized version of __do_get_(un)signed which avoids redundant copies.
 #    define _LIBCPP_ABI_OPTIMIZED_LOCALE_NUM_GET
-// In C++20 and later, don't derive std::plus from std::binary_function,
-// nor std::negate from std::unary_function.
-#    define _LIBCPP_ABI_NO_BINDER_BASES
 // Give reverse_iterator<T> one data member of type T, not two.
 // Also, in C++17 and later, don't derive iterator types from std::iterator.
 #    define _LIBCPP_ABI_NO_ITERATOR_BASES
@@ -1116,6 +1113,7 @@ _LIBCPP_BEGIN_NAMESPACE_STD _LIBCPP_END_NAMESPACE_STD
 #    define _LIBCPP_ENABLE_CXX17_REMOVED_BINDERS
 #    define _LIBCPP_ENABLE_CXX17_REMOVED_RANDOM_SHUFFLE
 #    define _LIBCPP_ENABLE_CXX17_REMOVED_UNEXPECTED_FUNCTIONS
+#    define _LIBCPP_ENABLE_CXX17_REMOVED_UNARY_BINARY_FUNCTION
 #  endif // _LIBCPP_ENABLE_CXX17_REMOVED_FEATURES
 
 #  if defined(_LIBCPP_ENABLE_CXX20_REMOVED_FEATURES)

libcxx/include/__functional/binary_function.h

@@ -18,14 +18,37 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
+#if _LIBCPP_STD_VER <= 14 || defined(_LIBCPP_ENABLE_CXX17_REMOVED_UNARY_BINARY_FUNCTION)
+
 template <class _Arg1, class _Arg2, class _Result>
-struct _LIBCPP_TEMPLATE_VIS binary_function
+struct _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX11 binary_function
 {
     typedef _Arg1   first_argument_type;
     typedef _Arg2   second_argument_type;
     typedef _Result result_type;
 };
 
+#endif // _LIBCPP_STD_VER <= 14 || defined(_LIBCPP_ENABLE_CXX17_REMOVED_UNARY_BINARY_FUNCTION)
+
+template <class _Arg1, class _Arg2, class _Result> struct __binary_function_keep_layout_base {
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+  using first_argument_type _LIBCPP_DEPRECATED_IN_CXX17 = _Arg1;
+  using second_argument_type _LIBCPP_DEPRECATED_IN_CXX17 = _Arg2;
+  using result_type _LIBCPP_DEPRECATED_IN_CXX17 = _Result;
+#endif
+};
+
+#if _LIBCPP_STD_VER <= 14 || defined(_LIBCPP_ENABLE_CXX17_REMOVED_UNARY_BINARY_FUNCTION)
+_LIBCPP_DIAGNOSTIC_PUSH
+_LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wdeprecated-declarations")
+template <class _Arg1, class _Arg2, class _Result>
+using __binary_function = binary_function<_Arg1, _Arg2, _Result>;
+_LIBCPP_DIAGNOSTIC_POP
+#else
+template <class _Arg1, class _Arg2, class _Result>
+using __binary_function = __binary_function_keep_layout_base<_Arg1, _Arg2, _Result>;
+#endif
+
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___FUNCTIONAL_BINARY_FUNCTION_H

libcxx/include/__functional/binary_negate.h

@@ -23,9 +23,9 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _Predicate>
 class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX17 binary_negate
-    : public binary_function<typename _Predicate::first_argument_type,
-                             typename _Predicate::second_argument_type,
-                             bool>
+    : public __binary_function<typename _Predicate::first_argument_type,
+                               typename _Predicate::second_argument_type,
+                               bool>
 {
     _Predicate __pred_;
 public:

libcxx/include/__functional/bind.h

@@ -264,10 +264,7 @@ __apply_functor(_Fp& __f, _BoundArgs& __bound_args, __tuple_indices<_Indx...>,
 }
 
 template<class _Fp, class ..._BoundArgs>
-class __bind
-#if _LIBCPP_STD_VER <= 17 || !defined(_LIBCPP_ABI_NO_BINDER_BASES)
-    : public __weak_result_type<typename decay<_Fp>::type>
-#endif
+class __bind : public __weak_result_type<typename decay<_Fp>::type>
 {
 protected:
     typedef typename decay<_Fp>::type _Fd;

libcxx/include/__functional/binder1st.h

@@ -23,8 +23,7 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class __Operation>
 class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX11 binder1st
-    : public unary_function<typename __Operation::second_argument_type,
-                            typename __Operation::result_type>
+    : public __unary_function<typename __Operation::second_argument_type, typename __Operation::result_type>
 {
 protected:
     __Operation                               op;

libcxx/include/__functional/binder2nd.h

@@ -23,8 +23,7 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class __Operation>
 class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX11 binder2nd
-    : public unary_function<typename __Operation::first_argument_type,
-                            typename __Operation::result_type>
+    : public __unary_function<typename __Operation::first_argument_type, typename __Operation::result_type>
 {
 protected:
     __Operation                                op;

libcxx/include/__functional/function.h

@@ -85,7 +85,7 @@ struct __maybe_derive_from_unary_function
 
 template<class _Rp, class _A1>
 struct __maybe_derive_from_unary_function<_Rp(_A1)>
-    : public unary_function<_A1, _Rp>
+    : public __unary_function<_A1, _Rp>
 {
 };
 
@@ -96,7 +96,7 @@ struct __maybe_derive_from_binary_function
 
 template<class _Rp, class _A1, class _A2>
 struct __maybe_derive_from_binary_function<_Rp(_A1, _A2)>
-    : public binary_function<_A1, _A2, _Rp>
+    : public __binary_function<_A1, _A2, _Rp>
 {
 };
 
@@ -956,10 +956,8 @@ class __func<_Rp1(^)(_ArgTypes1...), _Alloc, _Rp(_ArgTypes...)>
 
 template<class _Rp, class ..._ArgTypes>
 class _LIBCPP_TEMPLATE_VIS function<_Rp(_ArgTypes...)>
-#if _LIBCPP_STD_VER <= 17 || !defined(_LIBCPP_ABI_NO_BINDER_BASES)
     : public __function::__maybe_derive_from_unary_function<_Rp(_ArgTypes...)>,
       public __function::__maybe_derive_from_binary_function<_Rp(_ArgTypes...)>
-#endif
 {
 #ifndef _LIBCPP_ABI_OPTIMIZED_FUNCTION
     typedef __function::__value_func<_Rp(_ArgTypes...)> __func;