[libc++] Remove std::function in C++03

`std::function` has been deprecated for a few releases now. Remove it with an option to opt-back-in with a note that this option will be removed in LLVM 16.

Reviewed By: ldionne, #libc

Spies: #libc_vendors, EricWF, jloser, libcxx-commits

Differential Revision: https://reviews.llvm.org/D127908

Author: philnik777

libcxx/docs/ReleaseNotes.rst

@@ -148,6 +148,10 @@ API Changes
   will be removed in LLVM 17. You can disable the deprecation warnings by defining
   ``_LIBCPP_NO_EXPERIMENTAL_DEPRECATION_WARNING_SEARCHERS``.
 
+- ``std::function`` has been removed in C++03. If you are using it, please remove usages
+  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.
+
 ABI Changes
 -----------
 

libcxx/include/__functional/function.h

@@ -1242,7 +1242,7 @@ void
 swap(function<_Rp(_ArgTypes...)>& __x, function<_Rp(_ArgTypes...)>& __y) _NOEXCEPT
 {return __x.swap(__y);}
 
-#else // _LIBCPP_CXX03_LANG
+#elif defined(_LIBCPP_ENABLE_CXX03_FUNCTION)
 
 namespace __function {
 
@@ -2808,7 +2808,7 @@ void
 swap(function<_Fp>& __x, function<_Fp>& __y)
 {return __x.swap(__y);}
 
-#endif
+#endif // _LIBCPP_CXX03_LANG
 
 _LIBCPP_END_NAMESPACE_STD
 

libcxx/test/libcxx/utilities/function.objects/func.wrap/depr_in_cxx03.verify.cpp

@@ -13,6 +13,8 @@
 
 // REQUIRES: c++03
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_ENABLE_CXX03_FUNCTION
+
 #include <functional>
 #include "test_macros.h"
 

libcxx/test/libcxx/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/move_reentrant.pass.cpp

@@ -13,7 +13,7 @@
 // function& operator=(function &&);
 
 // This test runs in C++03, but we have deprecated using std::function in C++03.
-// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS -D_LIBCPP_ENABLE_CXX03_FUNCTION
 
 #include <functional>
 #include <cassert>

libcxx/test/libcxx/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/nullptr_t_assign_reentrant.pass.cpp

@@ -13,7 +13,7 @@
 // function& operator=(nullptr_t);
 
 // This test runs in C++03, but we have deprecated using std::function in C++03.
-// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS -D_LIBCPP_ENABLE_CXX03_FUNCTION
 
 #include <functional>
 #include <cassert>

libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/addressof.pass.cpp

@@ -11,7 +11,7 @@
 // class function<R(ArgTypes...)>
 
 // This test runs in C++03, but we have deprecated using std::function in C++03.
-// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS -D_LIBCPP_ENABLE_CXX03_FUNCTION
 
 // Make sure we can use std::function with a type that has a hostile overload
 // of operator&().

libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.alg/swap.pass.cpp

@@ -14,7 +14,7 @@
 //   void swap(function<R(ArgTypes...)>&, function<R(ArgTypes...)>&) noexcept;
 
 // This test runs in C++03, but we have deprecated using std::function in C++03.
-// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS -D_LIBCPP_ENABLE_CXX03_FUNCTION
 
 #include <functional>
 #include <cstdlib>

libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.cap/operator_bool.pass.cpp

@@ -13,7 +13,7 @@
 // explicit operator bool() const
 
 // This test runs in C++03, but we have deprecated using std::function in C++03.
-// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS -D_LIBCPP_ENABLE_CXX03_FUNCTION
 
 #include <functional>
 #include <cassert>

libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/F.pass.cpp

@@ -13,7 +13,7 @@
 // function(F);
 
 // This test runs in C++03, but we have deprecated using std::function in C++03.
-// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS -D_LIBCPP_ENABLE_CXX03_FUNCTION
 
 #include <functional>
 #include <cassert>

libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/F_assign.pass.cpp

@@ -16,7 +16,7 @@
 //   operator=(F f);
 
 // This test runs in C++03, but we have deprecated using std::function in C++03.
-// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS -D_LIBCPP_ENABLE_CXX03_FUNCTION
 
 #include <functional>
 #include <cassert>

libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/F_incomplete.pass.cpp

@@ -15,7 +15,7 @@
 // Allow incomplete argument types in the __is_callable check
 
 // This test runs in C++03, but we have deprecated using std::function in C++03.
-// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS -D_LIBCPP_ENABLE_CXX03_FUNCTION
 
 #include <functional>
 #include <cassert>

libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/F_nullptr.pass.cpp

@@ -16,7 +16,7 @@
 // See https://llvm.org/PR23589
 
 // This test runs in C++03, but we have deprecated using std::function in C++03.
-// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS -D_LIBCPP_ENABLE_CXX03_FUNCTION
 
 //------------------------------------------------------------------------------
 // TESTING std::function<...>::__not_null(Callable)

libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc.pass.cpp

@@ -16,7 +16,7 @@
 // This signature was removed in C++17
 
 // This test runs in C++03, but we have deprecated using std::function in C++03.
-// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS -D_LIBCPP_ENABLE_CXX03_FUNCTION
 
 #include <functional>
 #include <cassert>

libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_F.pass.cpp

@@ -14,7 +14,7 @@
 // template<class F, class A> function(allocator_arg_t, const A&, F);
 
 // This test runs in C++03, but we have deprecated using std::function in C++03.
-// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS -D_LIBCPP_ENABLE_CXX03_FUNCTION
 
 #include <functional>
 #include <cassert>

libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_function.pass.cpp

@@ -14,7 +14,7 @@
 // template<class A> function(allocator_arg_t, const A&, const function&);
 
 // This test runs in C++03, but we have deprecated using std::function in C++03.
-// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS -D_LIBCPP_ENABLE_CXX03_FUNCTION
 
 #include <functional>
 #include <cassert>

libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_nullptr.pass.cpp

@@ -16,7 +16,7 @@
 // This signature was removed in C++17
 
 // This test runs in C++03, but we have deprecated using std::function in C++03.
-// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS -D_LIBCPP_ENABLE_CXX03_FUNCTION
 
 #include <functional>
 #include <cassert>

libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/copy_assign.pass.cpp

@@ -13,7 +13,7 @@
 // function& operator=(const function& f);
 
 // This test runs in C++03, but we have deprecated using std::function in C++03.
-// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS -D_LIBCPP_ENABLE_CXX03_FUNCTION
 
 #include <functional>
 #include <cassert>

libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/copy_move.pass.cpp

@@ -18,7 +18,7 @@
 // function(function&& f); // noexcept in C++20
 
 // This test runs in C++03, but we have deprecated using std::function in C++03.
-// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS -D_LIBCPP_ENABLE_CXX03_FUNCTION
 
 #include <functional>
 #include <memory>

libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/default.pass.cpp

@@ -13,7 +13,7 @@
 // function();
 
 // This test runs in C++03, but we have deprecated using std::function in C++03.
-// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS -D_LIBCPP_ENABLE_CXX03_FUNCTION
 
 #include <functional>
 #include <cassert>

libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/nullptr_t.pass.cpp

@@ -13,7 +13,7 @@
 // function(nullptr_t);
 
 // This test runs in C++03, but we have deprecated using std::function in C++03.
-// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS -D_LIBCPP_ENABLE_CXX03_FUNCTION
 
 #include <functional>
 #include <cassert>

libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/nullptr_t_assign.pass.cpp

@@ -13,7 +13,7 @@
 // function& operator=(nullptr_t);
 
 // This test runs in C++03, but we have deprecated using std::function in C++03.
-// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS -D_LIBCPP_ENABLE_CXX03_FUNCTION
 
 #include <functional>
 #include <cassert>

libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.inv/invoke.pass.cpp

@@ -13,7 +13,7 @@
 // R operator()(ArgTypes... args) const
 
 // This test runs in C++03, but we have deprecated using std::function in C++03.
-// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS -D_LIBCPP_ENABLE_CXX03_FUNCTION
 
 // Address Sanitizer doesn't instrument weak symbols on Linux. When a key
 // function is defined for bad_function_call's vtable, its typeinfo and vtable

libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.mod/assign_F_alloc.pass.cpp

@@ -14,7 +14,7 @@
 //     This call was removed post-C++14
 
 // This test runs in C++03, but we have deprecated using std::function in C++03.
-// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS -D_LIBCPP_ENABLE_CXX03_FUNCTION
 
 #include <functional>
 #include <cassert>

libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.mod/swap.pass.cpp

@@ -13,7 +13,7 @@
 // void swap(function& other);
 
 // This test runs in C++03, but we have deprecated using std::function in C++03.
-// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS -D_LIBCPP_ENABLE_CXX03_FUNCTION
 
 #include <functional>
 #include <cassert>

libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.nullptr/operator_==.pass.cpp

@@ -23,7 +23,7 @@
 //   bool operator!=(nullptr_t, const function<R(ArgTypes...)>&);
 
 // This test runs in C++03, but we have deprecated using std::function in C++03.
-// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS -D_LIBCPP_ENABLE_CXX03_FUNCTION
 
 #include <functional>
 #include <cassert>

libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.targ/target.pass.cpp

@@ -20,7 +20,7 @@
 //   target() const;
 
 // This test runs in C++03, but we have deprecated using std::function in C++03.
-// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS -D_LIBCPP_ENABLE_CXX03_FUNCTION
 
 // UNSUPPORTED: no-rtti
 

libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.targ/target_type.pass.cpp

@@ -13,7 +13,7 @@
 // const std::type_info& target_type() const;
 
 // This test runs in C++03, but we have deprecated using std::function in C++03.
-// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS -D_LIBCPP_ENABLE_CXX03_FUNCTION
 
 // UNSUPPORTED: no-rtti
 

libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/types.pass.cpp

@@ -22,7 +22,7 @@
 //  };
 
 // This test runs in C++03, but we have deprecated using std::function in C++03.
-// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS -D_LIBCPP_ENABLE_CXX03_FUNCTION
 
 #include <functional>
 #include <type_traits>