Patchwork [v3] --enable-extern-template

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Submitter Benjamin Kosnik
Date March 4, 2011, 9:30 p.m.
Message ID <20110304133005.3e8c12d9@shotwell>
Download mbox | patch
Permalink /patch/85442/
State New
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Comments

Benjamin Kosnik - March 4, 2011, 9:30 p.m.
C++0x linkage audit for "extern template" usage.

There is no behavior change here, just an additional group in the src
Makefile. The previous macro, _GLIBCXX_EXTERN_TEMPLATE is used as
before.

This patch allows building libstdc++.so/libstdc++.a
without extern template and the instantation files that are required
with it, by configuration with --disable-extern-template. 

tested x86/linux
tested x86_64/linux

-benjamin

Patch

2011-03-04  Benjamin Kosnik  <bkoz@chula>

	    * src/Makefile.am (inst_sources): Make source instantion files
	    conditional.
	    (XTEMPLATE_FLAGS): Make -fno-implicit-templates conditional.
	    * src/Makefile.in: Regenerate.
	    * src/valarray-inst.cc: Move to..
	    * src/valarray.cc: ...this.
	    * acinclude.m4 (GLIBCXX_ENABLE_EXTERN_TEMPLATE]): Define.
	    * configure.ac (GLIBCXX_ENABLE_EXTERN_TEMPLATE): Use it.
	    * configure: Regenerate.
	    * include/Makefile.am (stamp-extern-template): Add.
	    * include/Makefile.in: Regenerate.

	    * doc/xml/manual/configure.xml: Document --enable-extern-template.

	    * include/bits/locale_classes.tcc: Adjust comment.
	    * include/bits/locale_facets.tcc: Same.
	    * include/bits/basic_ios.tcc: Same.
	    * include/bits/istream.tcc: Same.
	    * include/bits/codecvt.h: Same.
	    * include/bits/ostream.tcc: Same.
	    * include/bits/sstream.tcc: Same.
	    * include/bits/c++config: Same.
	    * include/bits/basic_string.tcc: Same.
	    * include/bits/ostream_insert.h: Same.
	    * include/bits/locale_facets_nonio.tcc: Same.
	    * include/bits/streambuf.tcc: Same.
	    * include/bits/allocator.h: Same.
	    * include/bits/fstream.tcc: Same.

	    * testsuite/ext/profile/mutex_extensions_neg.cc: Adjust line 
	    numbers.

Index: src/valarray-inst.cc
===================================================================
--- src/valarray-inst.cc	(revision 170685)
+++ src/valarray-inst.cc	(working copy)
@@ -1,109 +0,0 @@ 
-// Explicit instantiation file.
-
-// Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2009
-// 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:
-//
-
-#include <valarray>
-
-namespace std _GLIBCXX_VISIBILITY(default)
-{
-_GLIBCXX_BEGIN_NAMESPACE_VERSION
-
-  // Some explicit instantiations.
-  template void
-     __valarray_fill(size_t* __restrict__, size_t, const size_t&);
-  
-  template void
-     __valarray_copy(const size_t* __restrict__, size_t, size_t* __restrict__);
-  
-  template valarray<size_t>::valarray(size_t);
-  template valarray<size_t>::valarray(const valarray<size_t>&);
-  template valarray<size_t>::~valarray();
-  template size_t valarray<size_t>::size() const;
-  template size_t& valarray<size_t>::operator[](size_t);
-
-  inline size_t
-  __valarray_product(const valarray<size_t>& __a)
-  {
-    typedef const size_t* __restrict__ _Tp;
-    const size_t __n = __a.size();
-    // XXX: This ugly cast is necessary because
-    //      valarray::operator[]() const return a VALUE!
-    //      Try to get the committee to correct that gross error.
-    valarray<size_t>& __t = const_cast<valarray<size_t>&>(__a);
-    return __valarray_product(&__t[0], &__t[0] + __n);
-  }
-  
-  // Map a gslice, described by its multidimensional LENGTHS
-  // and corresponding STRIDES, to a linear array of INDEXES
-  // for the purpose of indexing a flat, one-dimensional array
-  // representation of a gslice_array.
-  void
-  __gslice_to_index(size_t __o, const valarray<size_t>& __l,
-                    const valarray<size_t>& __s, valarray<size_t>& __i)
-  {
-    // There are as many dimensions as there are strides.
-    const size_t __n = __l.size();
-
-    // Holds current multi-index as we go through the gslice for the
-    // purpose of computing its linear-image.
-    valarray<size_t> __t(__l);
-
-    // Note that this should match the product of all numbers appearing
-    // in __l which describes the multidimensional sizes of the
-    // generalized slice.
-    const size_t __z = __i.size();
-
-    for (size_t __j = 0; __j < __z; ++__j)
-      {
-	// Compute the linear-index image of (t_0, ... t_{n-1}).
-	__i[__j] = __o;
-
-	--__t[__n - 1];
-	__o += __s[__n - 1];
-
-        // Process the next multi-index.  The loop ought to be
-        // backward since we're making a lexicographical visit.
-        for (size_t __k2 = __n - 1; __k2 && !__t[__k2]; --__k2)
-          {
-	    __o -= __s[__k2] * __l[__k2];
-	    __t[__k2] = __l[__k2];
-
-	    --__t[__k2 - 1];
-	    __o += __s[__k2 - 1];
-          }
-      }
-  }
-  
-  gslice::_Indexer::_Indexer(size_t __o, const valarray<size_t>& __l,
-                             const valarray<size_t>& __s)
-  : _M_count(1), _M_start(__o), _M_size(__l), _M_stride(__s),
-    _M_index(__l.size() == 0 ? 0 : __valarray_product(__l))
-  { __gslice_to_index(__o, __l, __s, _M_index); }  
-
-_GLIBCXX_END_NAMESPACE_VERSION
-} // namespace
Index: src/Makefile.am
===================================================================
--- src/Makefile.am	(revision 170685)
+++ src/Makefile.am	(working copy)
@@ -1,7 +1,7 @@ 
 ## Makefile for the src subdirectory of the GNU C++ Standard library.
 ##
 ## Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005
-## 2006, 2007, 2008, 2009, 2010
+## 2006, 2007, 2008, 2009, 2010, 2011
 ## Free Software Foundation, Inc.
 ##
 ## This file is part of the libstdc++ version 3 distribution.
@@ -108,7 +108,7 @@ 
 	messages_members.cc \
 	monetary_members.cc \
 	numeric_members.cc \
-	time_members.cc 
+	time_members.cc
 
 codecvt_members.cc: ${glibcxx_srcdir}/$(CCODECVT_CC)
 	$(LN_S) ${glibcxx_srcdir}/$(CCODECVT_CC) . || true
@@ -138,7 +138,8 @@ 
 # Source files linked in via configuration/make substitution for a
 # particular host, but with ad hoc naming rules.
 host_sources_extra = \
-	basic_file.cc c++locale.cc ${ldbl_compat_sources} ${parallel_sources}
+	basic_file.cc c++locale.cc \
+	${inst_sources} ${ldbl_compat_sources} ${parallel_sources}
 
 c++locale.cc: ${glibcxx_srcdir}/$(CLOCALE_CC)
 	$(LN_S) ${glibcxx_srcdir}/$(CLOCALE_CC) ./$@ || true
@@ -148,8 +149,8 @@ 
 
 if ENABLE_PARALLEL
 parallel_sources = parallel_settings.cc \
-	           compatibility-parallel_list.cc \
-	           compatibility-parallel_list-2.cc 
+		   compatibility-parallel_list.cc \
+		   compatibility-parallel_list-2.cc
 else
 parallel_sources =
 endif
@@ -160,7 +161,30 @@ 
 ldbl_compat_sources =
 endif
 
-# Sources present in the src directory.
+if ENABLE_EXTERN_TEMPLATE
+XTEMPLATE_FLAGS = -fno-implicit-templates
+inst_sources = \
+	allocator-inst.cc \
+	concept-inst.cc \
+	ext-inst.cc \
+	fstream-inst.cc \
+	ios-inst.cc \
+	iostream-inst.cc \
+	istream-inst.cc \
+	locale-inst.cc \
+	misc-inst.cc \
+	ostream-inst.cc \
+	sstream-inst.cc \
+	streambuf-inst.cc \
+	string-inst.cc \
+	wlocale-inst.cc \
+	wstring-inst.cc
+else
+XTEMPLATE_FLAGS =
+inst_sources =
+endif
+
+# Sources present in the src directory, always present.
 sources = \
 	atomic.cc \
 	bitmap_allocator.cc \
@@ -198,33 +222,18 @@ 
 	strstream.cc \
 	system_error.cc \
 	tree.cc \
-	allocator-inst.cc \
-	concept-inst.cc \
-	fstream-inst.cc \
-	ext-inst.cc \
-	ios-inst.cc \
-	iostream-inst.cc \
-	istream-inst.cc \
 	istream.cc \
-	locale-inst.cc \
-	misc-inst.cc \
-	ostream-inst.cc \
 	placeholders.cc \
 	regex.cc \
-	sstream-inst.cc \
-	streambuf-inst.cc \
 	streambuf.cc \
-	string-inst.cc \
-	valarray-inst.cc \
-	wlocale-inst.cc \
-	wstring-inst.cc \
 	mutex.cc \
 	condition_variable.cc \
 	chrono.cc \
 	thread.cc \
 	future.cc \
+	valarray.cc \
 	${host_sources} \
-	${host_sources_extra} 
+	${host_sources_extra}
 
 vpath % $(top_srcdir)/src
 vpath % $(top_srcdir)
@@ -240,7 +249,7 @@ 
 	$(top_builddir)/libsupc++/libsupc++convenience.la
 
 libstdc___la_LDFLAGS = \
-	-version-info $(libtool_VERSION) ${version_arg} -lm 
+	-version-info $(libtool_VERSION) ${version_arg} -lm
 
 libstdc___la_LINK = $(CXXLINK) $(libstdc___la_LDFLAGS)
 
@@ -383,7 +392,7 @@ 
 # OPTIMIZE_CXXFLAGS on the compile line so that -O2 can be overridden
 # as the occasion calls for it.
 AM_CXXFLAGS = \
-	-fno-implicit-templates \
+	$(XTEMPLATE_FLAGS) \
 	$(WARN_CXXFLAGS) \
 	$(OPTIMIZE_CXXFLAGS) \
 	$(CONFIG_CXXFLAGS)
@@ -407,8 +416,10 @@ 
 # correct solution is to add `--tag CXX' to LTCXXCOMPILE and maybe
 # CXXLINK, just after $(LIBTOOL), so that libtool doesn't have to
 # attempt to infer which configuration to use
-LTCXXCOMPILE = $(LIBTOOL) --tag CXX $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=compile \
-	       $(CXX) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CXXFLAGS) $(CXXFLAGS)
+LTCXXCOMPILE = $(LIBTOOL) --tag CXX \
+	       $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=compile \
+	       $(CXX) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) \
+	       $(AM_CXXFLAGS) $(CXXFLAGS)
 
 LTLDFLAGS = $(shell $(SHELL) $(top_srcdir)/../libtool-ldflags $(LDFLAGS))
 
Index: configure.ac
===================================================================
--- configure.ac	(revision 170685)
+++ configure.ac	(working copy)
@@ -132,6 +132,7 @@ 
 GLIBCXX_ENABLE_PARALLEL([yes])
 GLIBCXX_ENABLE_CXX_FLAGS
 GLIBCXX_ENABLE_FULLY_DYNAMIC_STRING([no])
+GLIBCXX_ENABLE_EXTERN_TEMPLATE([yes])
 
 # Checks for operating systems support that doesn't require linking.
 GLIBCXX_CHECK_SYSTEM_ERROR
Index: doc/xml/manual/configure.xml
===================================================================
--- doc/xml/manual/configure.xml	(revision 170685)
+++ doc/xml/manual/configure.xml	(working copy)
@@ -161,6 +161,29 @@ 
      </para>
  </listitem></varlistentry>
 
+
+ <varlistentry><term><code>--enable-libstdcxx-time</code></term>
+ <listitem><para>This is an abbreviated form of
+	<code>'--enable-libstdcxx-time=yes'</code>(described next).
+     </para>
+ </listitem></varlistentry>
+
+ <varlistentry><term><code>--enable-libstdcxx-time=OPTION</code></term>
+ <listitem><para>Enables link-type checks for the availability of the
+	clock_gettime clocks, used in the implementation of [time.clock],
+	and of the nanosleep and sched_yield functions, used in the
+	implementation of [thread.thread.this] of the current C++0x draft.
+	The choice OPTION=yes checks for the availability of the facilities
+	in libc and libposix4.  In case of need the latter is also linked
+	to libstdc++ as part of the build process.  OPTION=rt also searches
+	(and, in case, links) librt.   Note that the latter is not always
+	desirable because, in glibc, for example, in turn it triggers the
+	linking of libpthread too, which activates locking, a large overhead
+	for single-thread programs.  OPTION=no skips the tests completely.
+	The default is OPTION=no.
+    </para>
+ </listitem></varlistentry>
+
  <varlistentry><term><code>--enable-libstdcxx-debug</code></term>
  <listitem><para>Build separate debug libraries in addition to what is normally built.
 	By default, the debug libraries are compiled with
@@ -313,6 +336,19 @@ 
      </para>
  </listitem></varlistentry>
 
+
+ <varlistentry><term><code>--enable-extern-template</code>[default]</term>
+ <listitem><para>Use extern template to pre-instantiate all required
+ 	specializations for certain types defined in the standard libraries. 
+	These types include <classname>string</classname> and dependents like
+	<classname>char_traits</classname>, the templateized io classes,
+	<classname>allocator</classname>, and others.  
+	Disabling means that implicit
+	template generation will be used when compiling these types.  By
+	default, this option is on. This option can change the library ABI.
+     </para>
+ </listitem></varlistentry>
+
  <varlistentry><term><code>--disable-hosted-libstdcxx</code></term>
  <listitem>
    <para>
@@ -324,28 +360,6 @@ 
      </para>
  </listitem></varlistentry>
 
- <varlistentry><term><code>--enable-libstdcxx-time</code></term>
- <listitem><para>This is an abbreviated form of
-	<code>'--enable-libstdcxx-time=yes'</code>(described next).
-     </para>
- </listitem></varlistentry>
-
- <varlistentry><term><code>--enable-libstdcxx-time=OPTION</code></term>
- <listitem><para>Enables link-type checks for the availability of the
-	clock_gettime clocks, used in the implementation of [time.clock],
-	and of the nanosleep and sched_yield functions, used in the
-	implementation of [thread.thread.this] of the current C++0x draft.
-	The choice OPTION=yes checks for the availability of the facilities
-	in libc and libposix4.  In case of need the latter is also linked
-	to libstdc++ as part of the build process.  OPTION=rt also searches
-	(and, in case, links) librt.   Note that the latter is not always
-	desirable because, in glibc, for example, in turn it triggers the
-	linking of libpthread too, which activates locking, a large overhead
-	for single-thread programs.  OPTION=no skips the tests completely.
-	The default is OPTION=no.
-    </para>
- </listitem></varlistentry>
-
 </variablelist>
 
 </section>
Index: include/bits/locale_classes.tcc
===================================================================
--- include/bits/locale_classes.tcc	(revision 170685)
+++ include/bits/locale_classes.tcc	(working copy)
@@ -1,6 +1,6 @@ 
 // Locale support -*- C++ -*-
 
-// Copyright (C) 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
+// Copyright (C) 2007, 2008, 2009, 2010, 2011 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
@@ -241,7 +241,6 @@ 
 
   // Inhibit implicit instantiations for required instantiations,
   // which are defined via explicit instantiations elsewhere.
-  // NB: This syntax is a GNU extension.
 #if _GLIBCXX_EXTERN_TEMPLATE
   extern template class collate<char>;
   extern template class collate_byname<char>;
@@ -269,6 +268,6 @@ 
 #endif
 
 _GLIBCXX_END_NAMESPACE_VERSION
-} // namespace
+} // namespace std
 
 #endif
Index: include/bits/locale_facets.tcc
===================================================================
--- include/bits/locale_facets.tcc	(revision 170685)
+++ include/bits/locale_facets.tcc	(working copy)
@@ -1,7 +1,7 @@ 
 // Locale support -*- C++ -*-
 
 // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
-// 2006, 2007, 2008, 2009, 2010
+// 2006, 2007, 2008, 2009, 2010, 2011
 // Free Software Foundation, Inc.
 //
 // This file is part of the GNU ISO C++ Library.  This library is free
@@ -1276,7 +1276,6 @@ 
 
   // Inhibit implicit instantiations for required instantiations,
   // which are defined via explicit instantiations elsewhere.
-  // NB: This syntax is a GNU extension.
 #if _GLIBCXX_EXTERN_TEMPLATE
   extern template class numpunct<char>;
   extern template class numpunct_byname<char>;
Index: include/bits/basic_ios.tcc
===================================================================
--- include/bits/basic_ios.tcc	(revision 170685)
+++ include/bits/basic_ios.tcc	(working copy)
@@ -1,7 +1,7 @@ 
 // basic_ios member functions -*- C++ -*-
 
 // Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007,
-// 2009, 2010  Free Software Foundation, Inc.
+// 2009, 2010, 2011  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
@@ -175,7 +175,6 @@ 
 
   // Inhibit implicit instantiations for required instantiations,
   // which are defined via explicit instantiations elsewhere.
-  // NB:  This syntax is a GNU extension.
 #if _GLIBCXX_EXTERN_TEMPLATE
   extern template class basic_ios<char>;
 
@@ -185,6 +184,6 @@ 
 #endif
 
 _GLIBCXX_END_NAMESPACE_VERSION
-} // namespace
+} // namespace std
 
 #endif
Index: include/bits/istream.tcc
===================================================================
--- include/bits/istream.tcc	(revision 170685)
+++ include/bits/istream.tcc	(working copy)
@@ -1038,7 +1038,6 @@ 
 
   // Inhibit implicit instantiations for required instantiations,
   // which are defined via explicit instantiations elsewhere.
-  // NB:  This syntax is a GNU extension.
 #if _GLIBCXX_EXTERN_TEMPLATE
   extern template class basic_istream<char>;
   extern template istream& ws(istream&);
@@ -1090,6 +1089,6 @@ 
 #endif
 
 _GLIBCXX_END_NAMESPACE_VERSION
-} // namespace
+} // namespace std
 
 #endif
Index: include/bits/codecvt.h
===================================================================
--- include/bits/codecvt.h	(revision 170685)
+++ include/bits/codecvt.h	(working copy)
@@ -1,7 +1,7 @@ 
 // Locale support (codecvt) -*- C++ -*-
 
 // Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008,
-// 2009, 2010  Free Software Foundation, Inc.
+// 2009, 2010, 2011  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
@@ -476,7 +476,6 @@ 
 
   // Inhibit implicit instantiations for required instantiations,
   // which are defined via explicit instantiations elsewhere.
-  // NB: This syntax is a GNU extension.
 #if _GLIBCXX_EXTERN_TEMPLATE
   extern template class codecvt_byname<char, char, mbstate_t>;
 
@@ -502,6 +501,6 @@ 
 #endif
 
 _GLIBCXX_END_NAMESPACE_VERSION
-} // namespace
+} // namespace std
 
 #endif // _CODECVT_H
Index: include/bits/ostream.tcc
===================================================================
--- include/bits/ostream.tcc	(revision 170685)
+++ include/bits/ostream.tcc	(working copy)
@@ -357,7 +357,6 @@ 
 
   // Inhibit implicit instantiations for required instantiations,
   // which are defined via explicit instantiations elsewhere.
-  // NB:  This syntax is a GNU extension.
 #if _GLIBCXX_EXTERN_TEMPLATE
   extern template class basic_ostream<char>;
   extern template ostream& endl(ostream&);
@@ -405,6 +404,6 @@ 
 #endif
 
 _GLIBCXX_END_NAMESPACE_VERSION
-} // namespace
+} // namespace std
 
 #endif
Index: include/bits/sstream.tcc
===================================================================
--- include/bits/sstream.tcc	(revision 170685)
+++ include/bits/sstream.tcc	(working copy)
@@ -270,7 +270,6 @@ 
 
   // Inhibit implicit instantiations for required instantiations,
   // which are defined via explicit instantiations elsewhere.
-  // NB:  This syntax is a GNU extension.
 #if _GLIBCXX_EXTERN_TEMPLATE
   extern template class basic_stringbuf<char>;
   extern template class basic_istringstream<char>;
@@ -286,6 +285,6 @@ 
 #endif
 
 _GLIBCXX_END_NAMESPACE_VERSION
-} // namespace
+} // namespace std
 
 #endif
Index: include/bits/c++config
===================================================================
--- include/bits/c++config	(revision 170685)
+++ include/bits/c++config	(working copy)
@@ -109,9 +109,7 @@ 
 // Special case: _GLIBCXX_EXTERN_TEMPLATE == -1 disallows extern
 // templates only in basic_string, thus activating its debug-mode
 // checks even at -O0.
-#ifndef _GLIBCXX_EXTERN_TEMPLATE
-# define _GLIBCXX_EXTERN_TEMPLATE 1
-#endif
+#define _GLIBCXX_EXTERN_TEMPLATE
 
 /*
   Outline of libstdc++ namespaces.
Index: include/bits/basic_string.tcc
===================================================================
--- include/bits/basic_string.tcc	(revision 170685)
+++ include/bits/basic_string.tcc	(working copy)
@@ -1130,7 +1130,6 @@ 
 
   // Inhibit implicit instantiations for required instantiations,
   // which are defined via explicit instantiations elsewhere.
-  // NB: This syntax is a GNU extension.
 #if _GLIBCXX_EXTERN_TEMPLATE > 0
   extern template class basic_string<char>;
   extern template
@@ -1164,6 +1163,6 @@ 
 #endif
 
 _GLIBCXX_END_NAMESPACE_VERSION
-} // namespace
+} // namespace std
 
 #endif
Index: include/bits/ostream_insert.h
===================================================================
--- include/bits/ostream_insert.h	(revision 170685)
+++ include/bits/ostream_insert.h	(working copy)
@@ -114,7 +114,6 @@ 
 
   // Inhibit implicit instantiations for required instantiations,
   // which are defined via explicit instantiations elsewhere.
-  // NB:  This syntax is a GNU extension.
 #if _GLIBCXX_EXTERN_TEMPLATE
   extern template ostream& __ostream_insert(ostream&, const char*, streamsize);
 
@@ -125,6 +124,6 @@ 
 #endif
 
 _GLIBCXX_END_NAMESPACE_VERSION
-} // namespace
+} // namespace std
 
 #endif /* _OSTREAM_INSERT_H */
Index: include/bits/locale_facets_nonio.tcc
===================================================================
--- include/bits/locale_facets_nonio.tcc	(revision 170685)
+++ include/bits/locale_facets_nonio.tcc	(working copy)
@@ -1,6 +1,6 @@ 
 // Locale support -*- C++ -*-
 
-// Copyright (C) 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
+// Copyright (C) 2007, 2008, 2009, 2010, 2011 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
@@ -1215,7 +1215,6 @@ 
 
   // Inhibit implicit instantiations for required instantiations,
   // which are defined via explicit instantiations elsewhere.
-  // NB: This syntax is a GNU extension.
 #if _GLIBCXX_EXTERN_TEMPLATE
   extern template class moneypunct<char, false>;
   extern template class moneypunct<char, true>;
@@ -1369,6 +1368,6 @@ 
 #endif
 
 _GLIBCXX_END_NAMESPACE_VERSION
-} // namespace
+} // namespace std
 
 #endif
Index: include/bits/streambuf.tcc
===================================================================
--- include/bits/streambuf.tcc	(revision 170685)
+++ include/bits/streambuf.tcc	(working copy)
@@ -146,7 +146,6 @@ 
 
   // Inhibit implicit instantiations for required instantiations,
   // which are defined via explicit instantiations elsewhere.
-  // NB:  This syntax is a GNU extension.
 #if _GLIBCXX_EXTERN_TEMPLATE
   extern template class basic_streambuf<char>;
   extern template
@@ -172,6 +171,6 @@ 
 #endif
 
 _GLIBCXX_END_NAMESPACE_VERSION
-} // namespace
+} // namespace std
 
 #endif
Index: include/bits/allocator.h
===================================================================
--- include/bits/allocator.h	(revision 170685)
+++ include/bits/allocator.h	(working copy)
@@ -1,7 +1,7 @@ 
 // Allocators -*- C++ -*-
 
-// Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
-// Free Software Foundation, Inc.
+// Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
+// 2011 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
@@ -139,7 +139,6 @@ 
 
   // Inhibit implicit instantiations for required instantiations,
   // which are defined via explicit instantiations elsewhere.
-  // NB: This syntax is a GNU extension.
 #if _GLIBCXX_EXTERN_TEMPLATE
   extern template class allocator<char>;
   extern template class allocator<wchar_t>;
@@ -235,6 +234,6 @@ 
 #endif
 
 _GLIBCXX_END_NAMESPACE_VERSION
-} // namespace
+} // namespace std
 
 #endif
Index: include/bits/fstream.tcc
===================================================================
--- include/bits/fstream.tcc	(revision 170685)
+++ include/bits/fstream.tcc	(working copy)
@@ -964,7 +964,6 @@ 
 
   // Inhibit implicit instantiations for required instantiations,
   // which are defined via explicit instantiations elsewhere.
-  // NB:  This syntax is a GNU extension.
 #if _GLIBCXX_EXTERN_TEMPLATE
   extern template class basic_filebuf<char>;
   extern template class basic_ifstream<char>;
@@ -980,6 +979,6 @@ 
 #endif
 
 _GLIBCXX_END_NAMESPACE_VERSION
-} // namespace
+} // namespace std
 
 #endif
Index: include/Makefile.am
===================================================================
--- include/Makefile.am	(revision 170685)
+++ include/Makefile.am	(working copy)
@@ -1067,6 +1067,14 @@ 
 	echo 0 > stamp-namespace-version
 endif
 
+if ENABLE_EXTERN_TEMPLATE
+stamp-extern-template:
+	echo 1 > stamp-extern-template
+else
+stamp-extern-template:
+	echo 0 > stamp-extern-template
+endif
+
 if ENABLE_VISIBILITY
 stamp-visibility:
 	echo 1 > stamp-visibility
@@ -1082,10 +1090,12 @@ 
 			      stamp-${host_alias} \
 			      ${toplevel_srcdir}/gcc/DATESTAMP \
 			      stamp-namespace-version \
-			      stamp-visibility
+			      stamp-visibility \
+			      stamp-extern-template
 	@date=`cat ${toplevel_srcdir}/gcc/DATESTAMP` ;\
 	ns_version=`cat stamp-namespace-version` ;\
 	visibility=`cat stamp-visibility` ;\
+	externtemplate=`cat stamp-extern-template` ;\
 	ldbl_compat='s,g,g,' ;\
 	grep "^[ 	]*#[ 	]*define[ 	][ 	]*_GLIBCXX_LONG_DOUBLE_COMPAT[ 	][ 	]*1[ 	]*$$" \
 	${CONFIG_HEADER} > /dev/null 2>&1 \
@@ -1093,6 +1103,7 @@ 
 	sed -e "s,define __GLIBCXX__,define __GLIBCXX__ $$date," \
 	-e "s,define _GLIBCXX_INLINE_VERSION, define _GLIBCXX_INLINE_VERSION $$ns_version," \
 	-e "s,define _GLIBCXX_HAVE_ATTRIBUTE_VISIBILITY, define _GLIBCXX_HAVE_ATTRIBUTE_VISIBILITY $$visibility," \
+	-e "s,define _GLIBCXX_EXTERN_TEMPLATE, define _GLIBCXX_EXTERN_TEMPLATE $$externtemplate," \
 	-e "$$ldbl_compat" \
             < ${glibcxx_srcdir}/include/bits/c++config > $@ ;\
 	sed -e 's/HAVE_/_GLIBCXX_HAVE_/g' \
Index: testsuite/ext/profile/mutex_extensions_neg.cc
===================================================================
--- testsuite/ext/profile/mutex_extensions_neg.cc	(revision 170685)
+++ testsuite/ext/profile/mutex_extensions_neg.cc	(working copy)
@@ -22,4 +22,4 @@ 
 
 #include <vector>
 
-// { dg-error "multiple inlined namespaces" "" { target *-*-* } 243 }
+// { dg-error "multiple inlined namespaces" "" { target *-*-* } 241 }
Index: acinclude.m4
===================================================================
--- acinclude.m4	(revision 170685)
+++ acinclude.m4	(working copy)
@@ -1993,6 +1993,25 @@ 
 ])
 
 dnl
+dnl Use extern templates.
+dnl
+dnl --enable-extern-template defines _GLIBCXX_EXTERN_TEMPLATE to 1
+dnl --disable-extern-template defines _GLIBCXX_EXTERN_TEMPLATE to 0
+
+dnl  +  Usage:  GLIBCXX_ENABLE_TEMPLATE[(DEFAULT)]
+dnl       Where DEFAULT is `yes' or `no'.
+dnl
+AC_DEFUN([GLIBCXX_ENABLE_EXTERN_TEMPLATE], [
+
+  GLIBCXX_ENABLE(extern-template,$1,,[enable extern template])
+
+  AC_MSG_CHECKING([for extern template support])
+  AC_MSG_RESULT([$enable_extern_template])
+
+  GLIBCXX_CONDITIONAL(ENABLE_EXTERN_TEMPLATE, test $enable_extern_template = yes)
+])
+
+dnl
 dnl Check for parallel mode pre-requisites, including OpenMP support.
 dnl
 dnl  +  Usage:  GLIBCXX_ENABLE_PARALLEL