Commit 8ae404a2 authored by Louis Dionne's avatar Louis Dionne
Browse files

[libc++] Make sure std::is_scalar returns true for block types 

Summary:
The compiler already treats them as scalar types, so the library should
too. Furthermore, this allows blocks to be used in more places, for
example in std::optional, which requires an object type.

rdar://problem/57892832

Reviewers: dexonsmith, EricWF, mclow.lists
Differential Revision: https://reviews.llvm.org/D72708
parent b933d37c

libcxx/include/__config

+4 −0
Original line number Diff line number Diff line
@@ -463,6 +463,10 @@ typedef __char32_t char32_t; 
#define _LIBCPP_HAS_OBJC_ARC_WEAK

#endif



#if __has_extension(blocks)

#  define _LIBCPP_HAS_EXTENSION_BLOCKS

#endif



#if !(__has_feature(cxx_relaxed_constexpr))

#define _LIBCPP_HAS_NO_CXX14_CONSTEXPR

#endif

libcxx/include/type_traits

+6 −0
Original line number Diff line number Diff line
@@ -1016,11 +1016,17 @@ _LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_fundamental_v 


// is_scalar



template <class _Tp> struct __is_block : false_type {};

#if defined(_LIBCPP_HAS_EXTENSION_BLOCKS)

template <class _Rp, class ..._Args> struct __is_block<_Rp (^)(_Args...)> : true_type {};

#endif



template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_scalar

    : public integral_constant<bool, is_arithmetic<_Tp>::value     ||

                                     is_member_pointer<_Tp>::value ||

                                     is_pointer<_Tp>::value        ||

                                     __is_nullptr_t<_Tp>::value    ||

                                     __is_block<_Tp>::value        ||

                                     is_enum<_Tp>::value           > {};



template <> struct _LIBCPP_TEMPLATE_VIS is_scalar<nullptr_t> : public true_type {};

libcxx/test/libcxx/type_traits/is_scalar.objc.pass.mm

0 → 100644
+38 −0
Original line number Diff line number Diff line 
//===----------------------------------------------------------------------===//

//

// 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++98, c++03



// <type_traits>



// std::is_scalar



// Make sure we report that blocks are scalar types.



#include <type_traits>

#include <optional>



struct Foo { };

template <int> struct Arg { };



static_assert(std::is_scalar<void (^)(void)>::value, "");

static_assert(std::is_scalar<void (^)()>::value, "");

static_assert(std::is_scalar<void (^)(Arg<0>)>::value, "");

static_assert(std::is_scalar<void (^)(Arg<0>, Arg<1>)>::value, "");

static_assert(std::is_scalar<void (^)(Arg<0>, Arg<1>, Arg<2>)>::value, "");

static_assert(std::is_scalar<Foo (^)(void)>::value, "");

static_assert(std::is_scalar<Foo (^)()>::value, "");

static_assert(std::is_scalar<Foo (^)(Arg<0>)>::value, "");

static_assert(std::is_scalar<Foo (^)(Arg<0>, Arg<1>)>::value, "");

static_assert(std::is_scalar<Foo (^)(Arg<0>, Arg<1>, Arg<2>)>::value, "");





int main(int, char**) {

    std::optional<Foo (^)(Arg<0>)> opt; (void)opt;

    return 0;

}

libcxx/test/libcxx/utilities/optional/block.objc.pass.mm

0 → 100644
+26 −0
Original line number Diff line number Diff line 
//===----------------------------------------------------------------------===//

//

// 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++98, c++03, c++11, c++14



// <optional>



// This test makes sure that we can create a `std::optional` containing

// an Objective-C++ block.



#include <optional>

#include <cassert>



int main(int, char**)

{

    using Block = void (^)(void);

    std::optional<Block> block;

    assert(!block);



    return 0;

}