diff mbox

Add std::apply for C++17

Message ID 20160805235746.GA16057@redhat.com
State New
Headers show

Commit Message

Jonathan Wakely Aug. 5, 2016, 11:57 p.m. UTC 
To avoid a circular dependency between <tuple> and <functional> I've
moved std::__invoke to its own header.

In order to use std::__invoke in std::apply it needs to be constexpr,
which is easy, but the standard says that std::invoke isn't constexpr.
So we have to intentionally disallow std::invoke in constant
expressions even though it's implemented purely in terms of a
constexpr function.  Expect a ballot comment about that.

This also fixes a bug in the exception specifications of std::__invoke
and std::invoke, where the function type used as the template argument
to __is_nothrow_callable would have decayed its argument types, so we
need && there to prevent that.

	* doc/xml/manual/status_cxx2017.xml: Add missing LFTSv2 features.
	* doc/html/manual/status.html: Regenerate.
	* include/Makefile.am: Add new header.
	* include/Makefile.in: Regenerate.
	* include/bits/invoke.h: New header.
	(__invoke): Make constexpr. Add && to types in exception specification.
	* include/experimental/tuple (apply, __apply_impl): Fix non-reserved
	names. Include <bits/invoke.h> and use std::__invoke.
	* include/std/functional (__invfwd, __invoke_impl, __invoke): Move to
	new header.
	(invoke): Add && to types in exception specification.
	* include/std/tuple (apply, __apply_impl): Define for C++17.
	* testsuite/20_util/tuple/apply/1.cc: New test.
	* testsuite/20_util/tuple/element_access/get_neg.cc: Adjust dg-error
	lineno.

Tested powerpc64-linux, committed to trunk.
commit 031d50fec36dd04c1e086ab7060d497a441f0d8a
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Fri Aug 5 17:27:46 2016 +0100

    Add std::apply for C++17
    
    	* doc/xml/manual/status_cxx2017.xml: Add missing LFTSv2 features.
    	* doc/html/manual/status.html: Regenerate.
    	* include/Makefile.am: Add new header.
    	* include/Makefile.in: Regenerate.
    	* include/bits/invoke.h: New header.
    	(__invoke): Make constexpr. Add && to types in exception specification.
    	* include/experimental/tuple (apply, __apply_impl): Fix non-reserved
    	names. Include <bits/invoke.h> and use std::__invoke.
    	* include/std/functional (__invfwd, __invoke_impl, __invoke): Move to
    	new header.
    	(invoke): Add && to types in exception specification.
    	* include/std/tuple (apply, __apply_impl): Define for C++17.
    	* testsuite/20_util/tuple/apply/1.cc: New test.
    	* testsuite/20_util/tuple/element_access/get_neg.cc: Adjust dg-error
    	lineno.
diff mbox

Patch

diff --git a/libstdc++-v3/doc/xml/manual/status_cxx2017.xml b/libstdc++-v3/doc/xml/manual/status_cxx2017.xml
index 02aec25..55e3ff5 100644
--- a/libstdc++-v3/doc/xml/manual/status_cxx2017.xml
+++ b/libstdc++-v3/doc/xml/manual/status_cxx2017.xml
@@ -149,6 +149,41 @@  Feature-testing recommendations for C++</link>.
     </row>
 
     <row>
+      <entry> Library Fundamentals V1 TS Components: <code>apply</code> </entry>
+      <entry>
+	<link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0220r1.html">
+	P0220R1
+	</link>
+      </entry>
+      <entry align="center"> 7 </entry>
+      <entry> <code>__cpp_lib_apply >= 201603</code> </entry>
+    </row>
+
+    <row>
+      <?dbhtml bgcolor="#C8B0B0" ?>
+      <entry> Library Fundamentals V1 TS Components: <code>shared_ptr&lt;T[]&gt;</code> </entry>
+      <entry>
+	<link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0220r1.html">
+	P0220R1
+	</link>
+      </entry>
+      <entry align="center"> No </entry>
+      <entry> <code>__cpp_lib_shared_ptr_arrays >= 201603</code> </entry>
+    </row>
+
+    <row>
+      <?dbhtml bgcolor="#C8B0B0" ?>
+      <entry> Library Fundamentals V1 TS Components: Searchers </entry>
+      <entry>
+	<link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0220r1.html">
+	P0220R1
+	</link>
+      </entry>
+      <entry align="center"> No </entry>
+      <entry> <code>__cpp_lib_boyer_moore_searcher >= 201603</code> </entry>
+    </row>
+
+    <row>
       <entry> Constant View: A proposal for a <code>std::as_const</code> helper function template	</entry>
       <entry>
 	<link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="">
diff --git a/libstdc++-v3/include/Makefile.am b/libstdc++-v3/include/Makefile.am
index e2c4f63..ea992f0 100644
--- a/libstdc++-v3/include/Makefile.am
+++ b/libstdc++-v3/include/Makefile.am
@@ -112,6 +112,7 @@  bits_headers = \
 	${bits_srcdir}/hashtable.h \
 	${bits_srcdir}/hashtable_policy.h \
 	${bits_srcdir}/indirect_array.h \
+	${bits_srcdir}/invoke.h \
 	${bits_srcdir}/ios_base.h \
 	${bits_srcdir}/istream.tcc \
 	${bits_srcdir}/list.tcc \
diff --git a/libstdc++-v3/include/bits/invoke.h b/libstdc++-v3/include/bits/invoke.h
new file mode 100644
index 0000000..60405b5
--- /dev/null
+++ b/libstdc++-v3/include/bits/invoke.h
@@ -0,0 +1,104 @@ 
+// Implementation of INVOKE -*- C++ -*-
+
+// Copyright (C) 2016 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/bits/invoke.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{functional}
+ */
+
+#ifndef _GLIBCXX_INVOKE_H
+#define _GLIBCXX_INVOKE_H 1
+
+#pragma GCC system_header
+
+#if __cplusplus < 201103L
+# include <bits/c++0x_warning.h>
+#else
+
+#include <type_traits>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   *  @addtogroup utilities
+   *  @{
+   */
+
+  // Used by __invoke_impl instead of std::forward<_Tp> so that a
+  // reference_wrapper is converted to an lvalue-reference.
+  template<typename _Tp, typename _Up = typename __inv_unwrap<_Tp>::type>
+    constexpr _Up&&
+    __invfwd(typename remove_reference<_Tp>::type& __t) noexcept
+    { return static_cast<_Up&&>(__t); }
+
+  template<typename _Res, typename _Fn, typename... _Args>
+    constexpr _Res
+    __invoke_impl(__invoke_other, _Fn&& __f, _Args&&... __args)
+    { return std::forward<_Fn>(__f)(std::forward<_Args>(__args)...); }
+
+  template<typename _Res, typename _MemFun, typename _Tp, typename... _Args>
+    constexpr _Res
+    __invoke_impl(__invoke_memfun_ref, _MemFun&& __f, _Tp&& __t,
+		  _Args&&... __args)
+    { return (__invfwd<_Tp>(__t).*__f)(std::forward<_Args>(__args)...); }
+
+  template<typename _Res, typename _MemFun, typename _Tp, typename... _Args>
+    constexpr _Res
+    __invoke_impl(__invoke_memfun_deref, _MemFun&& __f, _Tp&& __t,
+		  _Args&&... __args)
+    {
+      return ((*std::forward<_Tp>(__t)).*__f)(std::forward<_Args>(__args)...);
+    }
+
+  template<typename _Res, typename _MemPtr, typename _Tp>
+    constexpr _Res
+    __invoke_impl(__invoke_memobj_ref, _MemPtr&& __f, _Tp&& __t)
+    { return __invfwd<_Tp>(__t).*__f; }
+
+  template<typename _Res, typename _MemPtr, typename _Tp>
+    constexpr _Res
+    __invoke_impl(__invoke_memobj_deref, _MemPtr&& __f, _Tp&& __t)
+    { return (*std::forward<_Tp>(__t)).*__f; }
+
+  /// Invoke a callable object.
+  template<typename _Callable, typename... _Args>
+    constexpr typename result_of<_Callable&&(_Args&&...)>::type
+    __invoke(_Callable&& __fn, _Args&&... __args)
+    noexcept(__is_nothrow_callable<_Callable(_Args&&...)>::value)
+    {
+      using __result_of = result_of<_Callable&&(_Args&&...)>;
+      using __type = typename __result_of::type;
+      using __tag = typename __result_of::__invoke_type;
+      return std::__invoke_impl<__type>(__tag{}, std::forward<_Callable>(__fn),
+					std::forward<_Args>(__args)...);
+    }
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif // C++11
+
+#endif // _GLIBCXX_INVOKE_H
diff --git a/libstdc++-v3/include/experimental/tuple b/libstdc++-v3/include/experimental/tuple
index 81e91bd..bfa1ed1 100644
--- a/libstdc++-v3/include/experimental/tuple
+++ b/libstdc++-v3/include/experimental/tuple
@@ -36,7 +36,7 @@ 
 #else
 
 #include <tuple>
-#include <functional>
+#include <bits/invoke.h>
 
 namespace std _GLIBCXX_VISIBILITY(default)
 {
@@ -54,20 +54,19 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
   template <typename _Fn, typename _Tuple, std::size_t... _Idx>
     constexpr decltype(auto)
-    __apply_impl(_Fn&& f, _Tuple&& t, std::index_sequence<_Idx...>)
+    __apply_impl(_Fn&& __f, _Tuple&& __t, std::index_sequence<_Idx...>)
     {
-      using _Wrap = _Maybe_wrap_member_pointer<decay_t<_Fn>>;
-      return _Wrap::__do_wrap(std::forward<_Fn>(f))(
-	  std::get<_Idx>(std::forward<_Tuple>(t))...);
+      return std::__invoke(std::forward<_Fn>(__f),
+			   std::get<_Idx>(std::forward<_Tuple>(__t))...);
     }
 
   template <typename _Fn, typename _Tuple>
     constexpr decltype(auto)
-    apply(_Fn&& f, _Tuple&& t)
+    apply(_Fn&& __f, _Tuple&& __t)
     {
       using _Indices =
-	std::make_index_sequence<std::tuple_size<std::decay_t<_Tuple>>::value>;
-      return __apply_impl(std::forward<_Fn>(f), std::forward<_Tuple>(t),
+	std::make_index_sequence<tuple_size_v<std::decay_t<_Tuple>>>;
+      return __apply_impl(std::forward<_Fn>(__f), std::forward<_Tuple>(__t),
 			  _Indices{});
     }
 
diff --git a/libstdc++-v3/include/std/functional b/libstdc++-v3/include/std/functional
index 4ca32c3..1de914e 100644
--- a/libstdc++-v3/include/std/functional
+++ b/libstdc++-v3/include/std/functional
@@ -56,6 +56,7 @@ 
 #include <type_traits>
 #include <bits/functexcept.h>
 #include <bits/functional_hash.h>
+#include <bits/invoke.h>
 
 namespace std _GLIBCXX_VISIBILITY(default)
 {
@@ -184,55 +185,6 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     : _Weak_result_type_impl<typename remove_cv<_Functor>::type>
     { };
 
-  // Used by __invoke_impl instead of std::forward<_Tp> so that a
-  // reference_wrapper is converted to an lvalue-reference.
-  template<typename _Tp, typename _Up = typename __inv_unwrap<_Tp>::type>
-    inline _Up&&
-    __invfwd(typename remove_reference<_Tp>::type& __t) noexcept
-    { return static_cast<_Up&&>(__t); }
-
-  template<typename _Res, typename _Fn, typename... _Args>
-    inline _Res
-    __invoke_impl(__invoke_other, _Fn&& __f, _Args&&... __args)
-    { return std::forward<_Fn>(__f)(std::forward<_Args>(__args)...); }
-
-  template<typename _Res, typename _MemFun, typename _Tp, typename... _Args>
-    inline _Res
-    __invoke_impl(__invoke_memfun_ref, _MemFun&& __f, _Tp&& __t,
-		  _Args&&... __args)
-    { return (__invfwd<_Tp>(__t).*__f)(std::forward<_Args>(__args)...); }
-
-  template<typename _Res, typename _MemFun, typename _Tp, typename... _Args>
-    inline _Res
-    __invoke_impl(__invoke_memfun_deref, _MemFun&& __f, _Tp&& __t,
-		  _Args&&... __args)
-    {
-      return ((*std::forward<_Tp>(__t)).*__f)(std::forward<_Args>(__args)...);
-    }
-
-  template<typename _Res, typename _MemPtr, typename _Tp>
-    inline _Res
-    __invoke_impl(__invoke_memobj_ref, _MemPtr&& __f, _Tp&& __t)
-    { return __invfwd<_Tp>(__t).*__f; }
-
-  template<typename _Res, typename _MemPtr, typename _Tp>
-    inline _Res
-    __invoke_impl(__invoke_memobj_deref, _MemPtr&& __f, _Tp&& __t)
-    { return (*std::forward<_Tp>(__t)).*__f; }
-
-  /// Invoke a callable object.
-  template<typename _Callable, typename... _Args>
-    inline typename result_of<_Callable&&(_Args&&...)>::type
-    __invoke(_Callable&& __fn, _Args&&... __args)
-    noexcept(__is_nothrow_callable<_Callable(_Args...)>::value)
-    {
-      using __result_of = result_of<_Callable&&(_Args&&...)>;
-      using __type = typename __result_of::type;
-      using __tag = typename __result_of::__invoke_type;
-      return std::__invoke_impl<__type>(__tag{}, std::forward<_Callable>(__fn),
-					std::forward<_Args>(__args)...);
-    }
-
 #if __cplusplus > 201402L
 # define __cpp_lib_invoke 201411
 
@@ -240,7 +192,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
   template<typename _Callable, typename... _Args>
     inline result_of_t<_Callable&&(_Args&&...)>
     invoke(_Callable&& __fn, _Args&&... __args)
-    noexcept(is_nothrow_callable_v<_Callable(_Args...)>)
+    noexcept(is_nothrow_callable_v<_Callable(_Args&&...)>)
     {
       return std::__invoke(std::forward<_Callable>(__fn),
 			   std::forward<_Args>(__args)...);
diff --git a/libstdc++-v3/include/std/tuple b/libstdc++-v3/include/std/tuple
index 484cb48..b9074cb 100644
--- a/libstdc++-v3/include/std/tuple
+++ b/libstdc++-v3/include/std/tuple
@@ -38,6 +38,7 @@ 
 #include <utility>
 #include <array>
 #include <bits/uses_allocator.h>
+#include <bits/invoke.h>
 
 namespace std _GLIBCXX_VISIBILITY(default)
 {
@@ -1635,6 +1636,27 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
         second(std::forward<_Args2>(std::get<_Indexes2>(__tuple2))...)
       { }
 
+#if __cplusplus > 201402L
+# define __cpp_lib_apply 201603
+
+  template <typename _Fn, typename _Tuple, size_t... _Idx>
+    constexpr decltype(auto)
+    __apply_impl(_Fn&& __f, _Tuple&& __t, index_sequence<_Idx...>)
+    {
+      return std::__invoke(std::forward<_Fn>(__f),
+			   std::get<_Idx>(std::forward<_Tuple>(__t))...);
+    }
+
+  template <typename _Fn, typename _Tuple>
+    constexpr decltype(auto)
+    apply(_Fn&& __f, _Tuple&& __t)
+    {
+      using _Indices = make_index_sequence<tuple_size_v<decay_t<_Tuple>>>;
+      return __apply_impl(std::forward<_Fn>(__f), std::forward<_Tuple>(__t),
+			  _Indices{});
+    }
+#endif // C++17
+
   /// @}
 
 _GLIBCXX_END_NAMESPACE_VERSION
diff --git a/libstdc++-v3/testsuite/20_util/tuple/apply/1.cc b/libstdc++-v3/testsuite/20_util/tuple/apply/1.cc
new file mode 100644
index 0000000..c12309c
--- /dev/null
+++ b/libstdc++-v3/testsuite/20_util/tuple/apply/1.cc
@@ -0,0 +1,67 @@ 
+// Copyright (C) 2014-2016 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-options "-std=gnu++17" }
+
+#include <tuple>
+#include <testsuite_hooks.h>
+
+#if  __cpp_lib_apply < 201603
+#  error "__cpp_lib_apply < 201603"
+#endif
+
+void
+test01()
+{
+  auto t = std::make_tuple(1, '2', 3.0);
+  std::apply( [&](int& i, char& c, double& d) {
+      VERIFY(&i == &std::get<int>(t));
+      VERIFY(&c == &std::get<char>(t));
+      VERIFY(&d == &std::get<double>(t));
+    }, t);
+}
+
+constexpr int func(int i, int j) { return i + j; }
+
+void
+test02()
+{
+  constexpr auto t = std::make_tuple(1, 2);
+  constexpr int i = std::apply(func, t);
+  VERIFY( i == 3 );
+}
+
+struct F
+{
+  int f(int i, int j) const { return i + j; }
+};
+
+void
+test03()
+{
+  auto t = std::make_tuple(F{}, 1, 2);
+  int r = std::apply(&F::f, t);
+  VERIFY( r == 3 );
+}
+
+int
+main()
+{
+  test01();
+  test02();
+  test03();
+}
diff --git a/libstdc++-v3/testsuite/20_util/tuple/element_access/get_neg.cc b/libstdc++-v3/testsuite/20_util/tuple/element_access/get_neg.cc
index 95ff697..5bcf576 100644
--- a/libstdc++-v3/testsuite/20_util/tuple/element_access/get_neg.cc
+++ b/libstdc++-v3/testsuite/20_util/tuple/element_access/get_neg.cc
@@ -17,7 +17,7 @@ 
 
 // { dg-options "-fno-show-column" }
 // { dg-do compile { target c++14 } }
-// { dg-error "in range" "" { target *-*-* } 1279 }
+// { dg-error "in range" "" { target *-*-* } 1280 }
 
 #include <tuple>