Implement LWG 2221: formatted output operator for nullptr

2019-01-10  Ville Voutilainen  <ville.voutilainen@gmail.com>
	    Jonathan Wakely  <jwakely@redhat.com>

	Implement LWG 2221
	* config/abi/pre/gnu.ver (GLIBCXX_3.4): Tighten patterns.
	(GLIBCXX_3.4.26): Add new exports.
	* include/Makefile.am: Add ostream-inst.cc. Move string-inst.cc to
	correct list of sources.
	* include/Makefile.in: Regenerate.
	* include/std/ostream (operator<<(nullptr_t)): New member function.
	* src/c++17/ostream-inst.cc: New file.
	* testsuite/27_io/basic_ostream/inserters_other/char/lwg2221.cc: New
	test.

Co-Authored-By: Jonathan Wakely <jwakely@redhat.com>

From-SVN: r267808

libstdc++-v3/ChangeLog

+2019-01-10  Ville Voutilainen  <ville.voutilainen@gmail.com>
+	    Jonathan Wakely  <jwakely@redhat.com>
+
+	Implement LWG 2221
+	* config/abi/pre/gnu.ver (GLIBCXX_3.4): Tighten patterns.
+	(GLIBCXX_3.4.26): Add new exports.
+	* include/Makefile.am: Add ostream-inst.cc. Move string-inst.cc to
+	correct list of sources.
+	* include/Makefile.in: Regenerate.
+	* include/std/ostream (operator<<(nullptr_t)): New member function.
+	* src/c++17/ostream-inst.cc: New file.
+	* testsuite/27_io/basic_ostream/inserters_other/char/lwg2221.cc: New
+	test.
+
 2019-01-10  Jonathan Wakely  <jwakely@redhat.com>
 
 	* testsuite/util/testsuite_fs.h (nonexistent_path): Include name

libstdc++-v3/config/abi/pre/gnu.ver

@@ -495,7 +495,7 @@ GLIBCXX_3.4 {
     _ZNSo8_M_writeEPKc[ilx];
     _ZNSo3put*;
     _ZNSo[5-9][a-z]*;
-    _ZNSolsE*[^g];
+    _ZNSolsE*[^Dg];
 
     # std::basic_ostream<wchar_t>
     _ZNSt13basic_ostreamIwSt11char_traitsIwEEC[12]Ev;
@@ -509,7 +509,7 @@ GLIBCXX_3.4 {
     _ZNSt13basic_ostreamIwSt11char_traitsIwEE5writeEPKw*;
     _ZNSt13basic_ostreamIwSt11char_traitsIwEE6sentry*;
     _ZNSt13basic_ostreamIwSt11char_traitsIwEE8_M_writeEPKw[ilx];
-    _ZNSt13basic_ostreamIwSt11char_traitsIwEElsE*[^g];
+    _ZNSt13basic_ostreamIwSt11char_traitsIwEElsE*[^Dg];
 
     # std::ostream operators and inserters
     _ZSt4end[ls]I[cw]St11char_traitsI[cw]EERSt13basic_ostream*;
@@ -2223,6 +2223,10 @@ GLIBCXX_3.4.26 {
     _ZNSt10filesystem7__cxx1128recursive_directory_iteratoraSEOS1_;
     _ZNSt10filesystem7__cxx1128recursive_directory_iteratorppEv;
 
+    # basic_ostream::operator<<(nullptr_t)
+    _ZNSolsEDn;
+    _ZNSt13basic_ostreamIwSt11char_traitsIwEElsEDn;
+
 } GLIBCXX_3.4.25;
 
 # Symbols in the support library (libsupc++) have their own tag.

libstdc++-v3/include/std/ostream

@@ -245,6 +245,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       operator<<(const void* __p)
       { return _M_insert(__p); }
 
+#if __cplusplus >= 201703L
+      __ostream_type&
+      operator<<(nullptr_t)
+      { return *this << "nullptr"; }
+#endif
+
       /**
        *  @brief  Extracting from another streambuf.
        *  @param  __sb  A pointer to a streambuf

libstdc++-v3/src/c++17/Makefile.am

@@ -41,6 +41,8 @@ endif
 if ENABLE_EXTERN_TEMPLATE
 # XTEMPLATE_FLAGS = -fno-implicit-templates
 inst_sources = \
+	ostream-inst.cc \
+	string-inst.cc \
 	$(extra_string_inst_sources)
 else
 # XTEMPLATE_FLAGS =
@@ -52,7 +54,6 @@ sources = \
 	fs_ops.cc \
 	fs_path.cc \
 	memory_resource.cc \
-	string-inst.cc \
 	$(extra_fs_sources)
 
 vpath % $(top_srcdir)/src/c++17

libstdc++-v3/src/c++17/Makefile.in

@@ -124,9 +124,10 @@ libc__17convenience_la_LIBADD =
 @ENABLE_DUAL_ABI_TRUE@am__objects_1 = cow-fs_dir.lo cow-fs_ops.lo \
 @ENABLE_DUAL_ABI_TRUE@	cow-fs_path.lo
 am__objects_2 = fs_dir.lo fs_ops.lo fs_path.lo memory_resource.lo \
-	string-inst.lo $(am__objects_1)
+	$(am__objects_1)
 @ENABLE_DUAL_ABI_TRUE@am__objects_3 = cow-string-inst.lo
-@ENABLE_EXTERN_TEMPLATE_TRUE@am__objects_4 = $(am__objects_3)
+@ENABLE_EXTERN_TEMPLATE_TRUE@am__objects_4 = ostream-inst.lo \
+@ENABLE_EXTERN_TEMPLATE_TRUE@	string-inst.lo $(am__objects_3)
 am_libc__17convenience_la_OBJECTS = $(am__objects_2) $(am__objects_4)
 libc__17convenience_la_OBJECTS = $(am_libc__17convenience_la_OBJECTS)
 AM_V_lt = $(am__v_lt_@AM_V@)
@@ -426,6 +427,8 @@ headers =
 
 # XTEMPLATE_FLAGS = -fno-implicit-templates
 @ENABLE_EXTERN_TEMPLATE_TRUE@inst_sources = \
+@ENABLE_EXTERN_TEMPLATE_TRUE@	ostream-inst.cc \
+@ENABLE_EXTERN_TEMPLATE_TRUE@	string-inst.cc \
 @ENABLE_EXTERN_TEMPLATE_TRUE@	$(extra_string_inst_sources)
 
 sources = \
@@ -433,7 +436,6 @@ sources = \
 	fs_ops.cc \
 	fs_path.cc \
 	memory_resource.cc \
-	string-inst.cc \
 	$(extra_fs_sources)
 
 libc__17convenience_la_SOURCES = $(sources)  $(inst_sources)

libstdc++-v3/src/c++17/ostream-inst.cc

+// std::ostream instantiations for C++17 -*- C++ -*-
+
+// Copyright (C) 2019 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/>.
+
+//
+// ISO C++ 14882:2017 28  Input/output library
+//
+
+#include <ostream>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+template basic_ostream<char>& basic_ostream<char>::operator<<(nullptr_t);
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+template basic_ostream<wchar_t>& basic_ostream<wchar_t>::operator<<(nullptr_t);
+#endif
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std

libstdc++-v3/testsuite/27_io/basic_ostream/inserters_other/char/lwg2221.cc

+// { dg-options "-std=gnu++17 -fno-inline" }
+// { dg-do link }
+
+#include <iostream>
+
+int main()
+{
+  std::cout << nullptr << std::endl;
+}