From d6e2b16376f19b09127324d4f5c2f8e6ce635687 Mon Sep 17 00:00:00 2001 From: Hans Wennborg Date: Wed, 17 Jan 2018 14:26:10 +0000 Subject: Merging r321963: ------------------------------------------------------------------------ r321963 | dim | 2018-01-07 08:45:11 -0800 (Sun, 07 Jan 2018) | 51 lines Add pre-C++11 is_constructible wrappers for 3 arguments Summary: After rL319736 for D28253 (which fixes PR28929), gcc cannot compile `` anymore in pre-C+11 modes, complaining: ``` In file included from /usr/include/c++/v1/memory:648:0, from test.cpp:1: /usr/include/c++/v1/memory: In static member function 'static std::__1::shared_ptr<_Tp> std::__1::shared_ptr<_Tp>::make_shared(_A0&, _A1&, _A2&)': /usr/include/c++/v1/memory:4365:5: error: wrong number of template arguments (4, should be at least 1) static_assert((is_constructible<_Tp, _A0, _A1, _A2>::value), "Can't construct object in make_shared" ); ^ In file included from /usr/include/c++/v1/memory:649:0, from test.cpp:1: /usr/include/c++/v1/type_traits:3198:29: note: provided for 'template struct std::__1::is_constructible' struct _LIBCPP_TEMPLATE_VIS is_constructible ^~~~~~~~~~~~~~~~ In file included from /usr/include/c++/v1/memory:648:0, from test.cpp:1: /usr/include/c++/v1/memory:4365:5: error: template argument 1 is invalid static_assert((is_constructible<_Tp, _A0, _A1, _A2>::value), "Can't construct object in make_shared" ); ^ /usr/include/c++/v1/memory: In static member function 'static std::__1::shared_ptr<_Tp> std::__1::shared_ptr<_Tp>::allocate_shared(const _Alloc&, _A0&, _A1&, _A2&)': /usr/include/c++/v1/memory:4444:5: error: wrong number of template arguments (4, should be at least 1) static_assert((is_constructible<_Tp, _A0, _A1, _A2>::value), "Can't construct object in allocate_shared" ); ^ In file included from /usr/include/c++/v1/memory:649:0, from test.cpp:1: /usr/include/c++/v1/type_traits:3198:29: note: provided for 'template struct std::__1::is_constructible' struct _LIBCPP_TEMPLATE_VIS is_constructible ^~~~~~~~~~~~~~~~ In file included from /usr/include/c++/v1/memory:648:0, from test.cpp:1: /usr/include/c++/v1/memory:4444:5: error: template argument 1 is invalid static_assert((is_constructible<_Tp, _A0, _A1, _A2>::value), "Can't construct object in allocate_shared" ); ^ ``` This is also reported in https://bugs.freebsd.org/224946 (FreeBSD is apparently one of the very few projects that regularly builds programs against libc++ with gcc). The reason is that the static assertions are invoking `is_constructible` with three arguments, while gcc does not have the built-in `is_constructible` feature, and the pre-C++11 `is_constructible` wrappers in `` only provide up to two arguments. I have added additional wrappers for three arguments, modified the `is_constructible` entry point to take three arguments instead, and added a simple test to is_constructible.pass.cpp. Reviewers: EricWF, mclow.lists Reviewed By: EricWF Subscribers: krytarowski, cfe-commits, emaste Differential Revision: https://reviews.llvm.org/D41805 ------------------------------------------------------------------------ git-svn-id: https://llvm.org/svn/llvm-project/libcxx/branches/release_60@322659 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/type_traits | 62 ++++++++++++++++++++-- .../meta.unary.prop/is_constructible.pass.cpp | 12 +++++ 2 files changed, 70 insertions(+), 4 deletions(-) diff --git a/include/type_traits b/include/type_traits index 7a6c99293..eb443ee0a 100644 --- a/include/type_traits +++ b/include/type_traits @@ -3172,6 +3172,14 @@ template false_type __is_constructible2_test(__any, _A0&, _A1&); +template +decltype((_Tp(_VSTD::declval<_A0>(), _VSTD::declval<_A1>(), _VSTD::declval<_A2>()), true_type())) +__is_constructible3_test(_Tp&, _A0&, _A1&, _A2&); + +template +false_type +__is_constructible3_test(__any, _A0&, _A1&, _A2&); + template struct __is_constructible0_imp // false, _Tp is not a scalar : public common_type @@ -3196,6 +3204,14 @@ struct __is_constructible2_imp // false, _Tp is not a scalar >::type {}; +template +struct __is_constructible3_imp // false, _Tp is not a scalar + : public common_type + < + decltype(__is_constructible3_test(declval<_Tp&>(), declval<_A0>(), declval<_A1>(), declval<_A2>())) + >::type + {}; + // handle scalars and reference types // Scalars are default constructible, references are not @@ -3215,6 +3231,11 @@ struct __is_constructible2_imp : public false_type {}; +template +struct __is_constructible3_imp + : public false_type + {}; + // Treat scalars and reference types separately template @@ -3235,6 +3256,12 @@ struct __is_constructible2_void_check _Tp, _A0, _A1> {}; +template +struct __is_constructible3_void_check + : public __is_constructible3_imp::value || is_reference<_Tp>::value, + _Tp, _A0, _A1, _A2> + {}; + // If any of T or Args is void, is_constructible should be false template @@ -3252,17 +3279,24 @@ struct __is_constructible2_void_check : public false_type {}; +template +struct __is_constructible3_void_check + : public false_type + {}; + // is_constructible entry point template + class _A1 = __is_construct::__nat, + class _A2 = __is_construct::__nat> struct _LIBCPP_TEMPLATE_VIS is_constructible - : public __is_constructible2_void_check::value + : public __is_constructible3_void_check::value || is_abstract<_Tp>::value || is_function<_Tp>::value || is_void<_A0>::value - || is_void<_A1>::value, - _Tp, _A0, _A1> + || is_void<_A1>::value + || is_void<_A2>::value, + _Tp, _A0, _A1, _A2> {}; template @@ -3282,6 +3316,16 @@ struct _LIBCPP_TEMPLATE_VIS is_constructible<_Tp, _A0, __is_construct::__nat> _Tp, _A0> {}; +template +struct _LIBCPP_TEMPLATE_VIS is_constructible<_Tp, _A0, _A1, __is_construct::__nat> + : public __is_constructible2_void_check::value + || is_abstract<_Tp>::value + || is_function<_Tp>::value + || is_void<_A0>::value + || is_void<_A1>::value, + _Tp, _A0, _A1> + {}; + // Array types are default constructible if their element type // is default constructible @@ -3300,6 +3344,11 @@ struct __is_constructible2_imp : public false_type {}; +template +struct __is_constructible3_imp + : public false_type + {}; + // Incomplete array types are not constructible template @@ -3317,6 +3366,11 @@ struct __is_constructible2_imp : public false_type {}; +template +struct __is_constructible3_imp + : public false_type + {}; + #endif // __has_feature(is_constructible) diff --git a/test/std/utilities/meta/meta.unary/meta.unary.prop/is_constructible.pass.cpp b/test/std/utilities/meta/meta.unary/meta.unary.prop/is_constructible.pass.cpp index 1f7c32a8c..b90363a5c 100644 --- a/test/std/utilities/meta/meta.unary/meta.unary.prop/is_constructible.pass.cpp +++ b/test/std/utilities/meta/meta.unary/meta.unary.prop/is_constructible.pass.cpp @@ -30,6 +30,7 @@ struct A { explicit A(int); A(int, double); + A(int, long, double); #if TEST_STD_VER >= 11 private: #endif @@ -106,6 +107,16 @@ void test_is_constructible() #endif } +template +void test_is_constructible() +{ + static_assert(( std::is_constructible::value), ""); + LIBCPP11_STATIC_ASSERT((std::__libcpp_is_constructible::type::value), ""); +#if TEST_STD_VER > 14 + static_assert(( std::is_constructible_v), ""); +#endif +} + template void test_is_not_constructible() { @@ -146,6 +157,7 @@ int main() test_is_constructible (); test_is_constructible (); test_is_constructible (); + test_is_constructible (); test_is_constructible (); test_is_not_constructible (); -- cgit v1.2.3