diff mbox

Default to --enable-libstdcxx-time=auto

Message ID 20130524075705.GK1377@tucnak.redhat.com
State New
Headers show

Commit Message

Jakub Jelinek May 24, 2013, 7:57 a.m. UTC 
On Thu, May 23, 2013 at 11:54:05PM +0200, Rainer Orth wrote:
> > Agreed, that seems the best course of action if that's an option.
> 
> I just remembered that we aren't there yet even on mainline:
> 
> * This snippet
> 
>   http://gcc.gnu.org/ml/gcc-patches/2013-05/msg01255.html
> 
>   is necessary to avoid bootstrap failure on Solaris 9.
> 
> * We'll need to link every C++ program with -lrt on Solaris, as
>   mentioned in the same message.  I suppose the best way to do this is
>   along the lines of libgfortran.spec, rather than duplicate the
>   necessary configury between g++ and libstdc++.  This might prove
>   pretty invasive for the testsuite, though, and delay the 4.8.1 release
>   quite a bit.

Ugh, that makes =auto pretty much unbackportable, but it seems Solaris is
the only problematic OS here.  The goal of
_ZNSt6chrono12steady_clock3nowEv@@GLIBCXX_3.4.19
already in 4.8.1 was to allow Linux users (and with partial backport of
=auto not including Solaris perhaps also FreeBSD/NetBSD/OpenBSD) to let
users that get C++ core language feature completeness also use this
(Jonathan/Benjamin, is that right?).

So, let's talk about other options, is constexpr/const on
std::chrono::steady_clock::is_steady
required by the standard (as in, could we export
_ZNSt6chrono12steady_clock9is_steadyE@@GLIBCXX_3.4.19
and let the library say which case it is, it would be constexpr when
we know for sure, and a static variable otherwise)?
But looking at C++11 draft, in [time.clock.steady]
it even says that is_steady is true (then we are violating the standard
even when we represent steady_clock as typedef system_clock steady_clock;).

Thus, what about this version (just slightly modified, headers remain the
same, but we export _ZNSt6chrono12steady_clock3nowEv@@GLIBCXX_3.4.19
even if monotonic clock isn't supported, it will just be work the same as
_ZNSt6chrono12system_clock3nowEv@@GLIBCXX_3.4.11 .  Programs compiled
against headers of the same libstdc++ as will be linked in dynamically
won't see a change, because they will never use this symbol of monotonic
clocks weren't determined to be there at configure time.  And we have a
fallback for the unlikely matching of newer headers with older libstdc++,
it will work roughly as before (in that steady_clock::now () will not be
steady), just with the tiny exception that in that case the code could
see that steady_clock::is_steady is true rather than false (but, can't
the code assume it from the standard anyway)?

I've also added the #ifdef HAVE_SYMVER_SYMBOL_RENAMING_RUNTIME_SUPPORT
guards in gnu.ver.

	Jakub
2013-05-24  Jakub Jelinek  <jakub@redhat.com>

	* src/c++11/chrono.cc: If _GLIBCXX_USE_CLOCK_MONOTONIC_SYSCALL,
	include unistd.h and sys/syscall.h.  If _GLIBCXX_COMPATIBILITY_CXX0X,
	don't define system_clock::is_steady, system_clock::now() and
	steady_clock::is_steady.
	(std::chrono::system_clock::now()): If
	_GLIBCXX_USE_CLOCK_MONOTONIC_SYSCALL, call
	syscall (SYS_clock_gettime, ...) instead of clock_gettime (...).
	(std::chrono::system_clock::now()): Likewise.  Add weak attribute
	if _GLIBCXX_COMPATIBILITY_CXX0X and compatibility-chrono.cc will
	be non-empty.
	* src/Makefile.am (cxx11_sources): Add compatibility-chrono.cc.
	(compatibility-chrono.lo, compatibility-chrono.o): New goals.
	* src/c++11/compatibility-chrono.cc: New file.
	* acinclude.m4 (GLIBCXX_ENABLE_LIBSTDCXX_TIME): On linux*, check for
	syscall (SYS_clock_gettime, CLOCK_MONOTONIC, &tp).
	* testsuite/util/testsuite_abi.cc (check_version): Add
	GLIBCXX_3.4.20 version and make it the latest.
	* config/abi/pre/gnu.ver (_ZNSt6chrono12steady_clock3nowEv): Export
	also @@GLIBCXX_3.4.19.  Move all symbols so far added for GCC 4.9 to
	@@GLIBCXX_3.4.20 instead.
	* config/abi/post/i386-linux-gnu/baseline_symbols.txt: Regenerated.
	* config/abi/post/s390x-linux-gnu/baseline_symbols.txt: Regenerated.
	* config/abi/post/powerpc64-linux-gnu/baseline_symbols.txt:
	Regenerated.
	* config/abi/post/powerpc64-linux-gnu/32/baseline_symbols.txt:
	Regenerated.
	* config/abi/post/x86_64-linux-gnu/baseline_symbols.txt: Regenerated.
	* config/abi/post/x86_64-linux-gnu/32/baseline_symbols.txt:
	Regenerated.
	* config/abi/post/powerpc-linux-gnu/baseline_symbols.txt: Regenerated.
	* config/abi/post/s390-linux-gnu/baseline_symbols.txt: Regenerated.
	* config/abi/post/i486-linux-gnu/baseline_symbols.txt: Regenerated.
	* config.h.in: Regenerated.
	* src/Makefile.in: Regenerated.
	* configure: Regenerated.
2013-05-24  Jakub Jelinek  <jakub@redhat.com>

	* src/c++11/chrono.cc: If _GLIBCXX_USE_CLOCK_MONOTONIC_SYSCALL,
	include unistd.h and sys/syscall.h.  If _GLIBCXX_COMPATIBILITY_CXX0X,
	don't define system_clock::is_steady, system_clock::now() and
	steady_clock::is_steady.
	(std::chrono::system_clock::now()): If
	_GLIBCXX_USE_CLOCK_MONOTONIC_SYSCALL, call
	syscall (SYS_clock_gettime, ...) instead of clock_gettime (...).
	(std::chrono::system_clock::now()): Likewise.  Add weak attribute
	if _GLIBCXX_COMPATIBILITY_CXX0X and compatibility-chrono.cc will
	be non-empty.
	* src/Makefile.am (cxx11_sources): Add compatibility-chrono.cc.
	(compatibility-chrono.lo, compatibility-chrono.o): New goals.
	* src/c++11/compatibility-chrono.cc: New file.
	* acinclude.m4 (GLIBCXX_ENABLE_LIBSTDCXX_TIME): On linux*, check for
	syscall (SYS_clock_gettime, CLOCK_MONOTONIC, &tp).
	* testsuite/util/testsuite_abi.cc (check_version): Add
	GLIBCXX_3.4.19 version and make it the latest.
	* config/abi/pre/gnu.ver (_ZNSt6chrono12steady_clock3nowEv): Export
	also @@GLIBCXX_3.4.19.
	* config/abi/post/i386-linux-gnu/baseline_symbols.txt: Regenerated.
	* config/abi/post/s390x-linux-gnu/baseline_symbols.txt: Regenerated.
	* config/abi/post/powerpc64-linux-gnu/baseline_symbols.txt:
	Regenerated.
	* config/abi/post/powerpc64-linux-gnu/32/baseline_symbols.txt:
	Regenerated.
	* config/abi/post/x86_64-linux-gnu/baseline_symbols.txt: Regenerated.
	* config/abi/post/x86_64-linux-gnu/32/baseline_symbols.txt:
	Regenerated.
	* config/abi/post/powerpc-linux-gnu/baseline_symbols.txt: Regenerated.
	* config/abi/post/s390-linux-gnu/baseline_symbols.txt: Regenerated.
	* config/abi/post/i486-linux-gnu/baseline_symbols.txt: Regenerated.
	* config.h.in: Regenerated.
	* src/Makefile.in: Regenerated.
	* configure: Regenerated.

--- libstdc++-v3/src/c++11/chrono.cc.jj	2013-03-16 08:07:57.000000000 +0100
+++ libstdc++-v3/src/c++11/chrono.cc	2013-05-23 15:33:07.238690149 +0200
@@ -22,7 +22,20 @@
 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 // <http://www.gnu.org/licenses/>.
 
+#include <bits/c++config.h>
+
+#ifndef _GLIBCXX_USE_CLOCK_MONOTONIC
+// If !_GLIBCXX_USE_CLOCK_MONOTONIC, std::chrono::steady_clock
+// is just a typedef to std::chrono::system_clock, for ABI compatibility
+// force it not to be a typedef now and export it anyway.  Programs
+// using the headers where it is a typedef will actually just use
+// std::chrono::system_clock instead, and this remains here just as a fallback.
+#define _GLIBCXX_USE_CLOCK_MONOTONIC
+#include <chrono>
+#undef _GLIBCXX_USE_CLOCK_MONOTONIC
+#else
 #include <chrono>
+#endif
 
 #ifdef _GLIBCXX_USE_C99_STDINT_TR1
 
@@ -32,13 +45,18 @@
      defined(_GLIBCXX_USE_GETTIMEOFDAY)
 #include <sys/time.h>
 #endif
+#ifdef _GLIBCXX_USE_CLOCK_MONOTONIC_SYSCALL
+#include <unistd.h>
+#include <sys/syscall.h>
+#endif
 
 namespace std _GLIBCXX_VISIBILITY(default)
 {
   namespace chrono
   {
   _GLIBCXX_BEGIN_NAMESPACE_VERSION
- 
+
+#ifndef _GLIBCXX_COMPATIBILITY_CXX0X
     constexpr bool system_clock::is_steady;
 
     system_clock::time_point
@@ -47,7 +65,11 @@ namespace std _GLIBCXX_VISIBILITY(defaul
 #ifdef _GLIBCXX_USE_CLOCK_REALTIME
       timespec tp;
       // -EINVAL, -EFAULT
+#ifdef _GLIBCXX_USE_CLOCK_MONOTONIC_SYSCALL
+      syscall(SYS_clock_gettime, CLOCK_REALTIME, &tp);
+#else
       clock_gettime(CLOCK_REALTIME, &tp);
+#endif
       return time_point(duration(chrono::seconds(tp.tv_sec)
 				 + chrono::nanoseconds(tp.tv_nsec)));
 #elif defined(_GLIBCXX_USE_GETTIMEOFDAY)
@@ -61,20 +83,35 @@ namespace std _GLIBCXX_VISIBILITY(defaul
       return system_clock::from_time_t(__sec);
 #endif
     }
+#endif
     
-#ifdef _GLIBCXX_USE_CLOCK_MONOTONIC
+#ifndef _GLIBCXX_COMPATIBILITY_CXX0X
     constexpr bool steady_clock::is_steady;
+#endif
 
+#if defined(_GLIBCXX_SYMVER_GNU) && defined(_GLIBCXX_SHARED) \
+    && defined(_GLIBCXX_HAVE_AS_SYMVER_DIRECTIVE) \
+    && defined(_GLIBCXX_HAVE_SYMVER_SYMBOL_RENAMING_RUNTIME_SUPPORT) \
+    && !defined(_GLIBCXX_COMPATIBILITY_CXX0X)
+    __attribute__((__weak__))
+#endif
     steady_clock::time_point
     steady_clock::now() noexcept
     {
+#ifndef _GLIBCXX_USE_CLOCK_MONOTONIC
+      return chrono::system_clock::now ();
+#else
       timespec tp;
       // -EINVAL, -EFAULT
+#ifdef _GLIBCXX_USE_CLOCK_MONOTONIC_SYSCALL
+      syscall(SYS_clock_gettime, CLOCK_MONOTONIC, &tp);
+#else
       clock_gettime(CLOCK_MONOTONIC, &tp);
+#endif
       return time_point(duration(chrono::seconds(tp.tv_sec)
 				 + chrono::nanoseconds(tp.tv_nsec)));
-    }
 #endif
+    }
 
   _GLIBCXX_END_NAMESPACE_VERSION
   } // namespace chrono
--- libstdc++-v3/src/Makefile.am.jj	2013-03-22 15:05:13.000000000 +0100
+++ libstdc++-v3/src/Makefile.am	2013-05-23 15:18:13.030217244 +0200
@@ -50,7 +50,8 @@ cxx98_sources = \
 cxx11_sources = \
 	compatibility-c++0x.cc \
 	compatibility-atomic-c++0x.cc \
-	compatibility-thread-c++0x.cc
+	compatibility-thread-c++0x.cc \
+	compatibility-chrono.cc
 
 libstdc___la_SOURCES = $(cxx98_sources) $(cxx11_sources)
 
@@ -97,6 +98,11 @@ compatibility-thread-c++0x.lo: compatibi
 compatibility-thread-c++0x.o: compatibility-thread-c++0x.cc
 	$(CXXCOMPILE) -std=gnu++11 -c $<
 
+compatibility-chrono.lo: compatibility-chrono.cc
+	$(LTCXXCOMPILE) -std=gnu++11 -c $<
+compatibility-chrono.o: compatibility-chrono.cc
+	$(CXXCOMPILE) -std=gnu++11 -c $<
+
 # A note on compatibility and static libraries.
 # 
 # static lib == linked against only this version, should not need compat
--- libstdc++-v3/src/c++11/compatibility-chrono.cc.jj	2013-05-23 15:05:13.907962675 +0200
+++ libstdc++-v3/src/c++11/compatibility-chrono.cc	2013-05-23 15:33:07.238690149 +0200
@@ -0,0 +1,58 @@
+// Compatibility symbols for previous versions, C++0x bits -*- C++ -*-
+
+// Copyright (C) 2013 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/>.
+
+#define _GLIBCXX_COMPATIBILITY_CXX0X
+#include <bits/c++config.h>
+
+#if defined(_GLIBCXX_SYMVER_GNU) && defined(_GLIBCXX_SHARED) \
+    && defined(_GLIBCXX_HAVE_AS_SYMVER_DIRECTIVE)\
+    && defined(_GLIBCXX_HAVE_SYMVER_SYMBOL_RENAMING_RUNTIME_SUPPORT)
+
+#define steady_clock steady_clockXX
+#include "chrono.cc"
+
+// The rename syntax for default exported names is
+//   asm (".symver name1,exportedname@GLIBCXX_3.4.17")
+//   asm (".symver name2,exportedname@@GLIBCXX_3.4.19")
+// In the future, GLIBCXX_ABI > 6 should remove all uses of
+// _GLIBCXX_*_SYMVER macros in this file.
+
+#define _GLIBCXX_3_4_17_SYMVER(XXname, name) \
+   extern "C" void \
+   _X##name() \
+   __attribute__ ((alias(#XXname))); \
+   asm (".symver " "_X" #name "," #name "@GLIBCXX_3.4.17");
+
+#define _GLIBCXX_3_4_19_SYMVER(XXname, name) \
+   extern "C" void \
+   _Y##name() \
+   __attribute__ ((alias(#XXname))); \
+   asm (".symver " "_Y" #name  "," #name "@@GLIBCXX_3.4.19");
+
+_GLIBCXX_3_4_17_SYMVER(_ZNSt6chrono14steady_clockXX3nowEv,
+		       _ZNSt6chrono12steady_clock3nowEv)
+_GLIBCXX_3_4_19_SYMVER(_ZNSt6chrono14steady_clockXX3nowEv,
+		       _ZNSt6chrono12steady_clock3nowEv)
+
+#endif
--- libstdc++-v3/acinclude.m4.jj	2013-04-10 08:32:08.000000000 +0200
+++ libstdc++-v3/acinclude.m4	2013-05-23 14:13:34.546224986 +0200
@@ -1274,6 +1274,31 @@ AC_DEFUN([GLIBCXX_ENABLE_LIBSTDCXX_TIME]
     fi
   fi
 
+  if test x"$ac_has_clock_monotonic" != x"yes"; then
+    case ${target_os} in
+      linux*)
+	AC_MSG_CHECKING([for clock_gettime syscall])
+	AC_TRY_COMPILE(
+	  [#include <unistd.h>
+	   #include <time.h>
+	   #include <sys/syscall.h>
+	  ],
+	  [#if _POSIX_TIMERS > 0 && defined(_POSIX_MONOTONIC_CLOCK)
+	    timespec tp;
+	   #endif
+	   syscall(SYS_clock_gettime, CLOCK_MONOTONIC, &tp);
+	   syscall(SYS_clock_gettime, CLOCK_REALTIME, &tp);
+	  ], [ac_has_clock_monotonic_syscall=yes], [ac_has_clock_monotonic_syscall=no])
+	AC_MSG_RESULT($ac_has_clock_monotonic_syscall)
+	if test x"$ac_has_clock_monotonic_syscall" = x"yes"; then
+	  AC_DEFINE(_GLIBCXX_USE_CLOCK_MONOTONIC_SYSCALL, 1,
+	  [ Defined if clock_gettime syscall has monotonic clock support. ])
+	  ac_has_clock_monotonic=yes
+	  ac_has_clock_realtime=yes
+	fi;;
+    esac
+  fi
+
   if test x"$ac_has_clock_monotonic" = x"yes"; then
     AC_DEFINE(_GLIBCXX_USE_CLOCK_MONOTONIC, 1,
       [ Defined if clock_gettime has monotonic clock support. ])
--- libstdc++-v3/testsuite/util/testsuite_abi.cc.jj	2013-03-16 08:09:29.000000000 +0100
+++ libstdc++-v3/testsuite/util/testsuite_abi.cc	2013-05-23 15:37:48.226285549 +0200
@@ -195,6 +195,7 @@ check_version(symbol& test, bool added)
       known_versions.push_back("GLIBCXX_3.4.16");
       known_versions.push_back("GLIBCXX_3.4.17");
       known_versions.push_back("GLIBCXX_3.4.18");
+      known_versions.push_back("GLIBCXX_3.4.19");
       known_versions.push_back("GLIBCXX_LDBL_3.4");
       known_versions.push_back("GLIBCXX_LDBL_3.4.7");
       known_versions.push_back("GLIBCXX_LDBL_3.4.10");
@@ -223,7 +224,7 @@ check_version(symbol& test, bool added)
 	test.version_status = symbol::incompatible;
 
       // Check that added symbols are added in the latest pre-release version.
-      bool latestp = (test.version_name == "GLIBCXX_3.4.18"
+      bool latestp = (test.version_name == "GLIBCXX_3.4.19"
 		     || test.version_name == "CXXABI_1.3.7"
 		     || test.version_name == "CXXABI_TM_1");
       if (added && !latestp)
--- libstdc++-v3/config/abi/pre/gnu.ver.jj	2013-03-16 08:09:38.000000000 +0100
+++ libstdc++-v3/config/abi/pre/gnu.ver	2013-05-23 15:29:15.511112789 +0200
@@ -1303,9 +1303,6 @@ GLIBCXX_3.4.17 {
     _ZN11__gnu_debug25_Safe_local_iterator_base9_M_attachEPNS_19_Safe_sequence_baseEb;
     _ZN11__gnu_debug25_Safe_local_iterator_base9_M_detachEv;
 
-    # std::chrono::steady_clock::now()
-    _ZNSt6chrono12steady_clock3nowEv;
-
     # std::numeric_limits<__int128> and <unsigned __int128>
     _ZNSt14numeric_limitsInE*;
     _ZNSt14numeric_limitsIoE*;
@@ -1323,6 +1320,12 @@ GLIBCXX_3.4.17 {
     _ZNSt13__future_base19_Async_state_commonD1Ev;
     _ZNSt13__future_base19_Async_state_commonD2Ev;
 
+#ifdef HAVE_SYMVER_SYMBOL_RENAMING_RUNTIME_SUPPORT
+   # GLIBCXX_ABI compatibility only.
+    # std::chrono::steady_clock::now()
+    _ZNSt6chrono12steady_clock3nowEv;
+#endif
+
 } GLIBCXX_3.4.16;
 
 GLIBCXX_3.4.18 {
@@ -1344,6 +1347,13 @@ GLIBCXX_3.4.18 {
 
 } GLIBCXX_3.4.17;
 
+GLIBCXX_3.4.19 {
+
+    # std::chrono::steady_clock::now()
+    _ZNSt6chrono12steady_clock3nowEv;
+
+} GLIBCXX_3.4.18;
+
 # Symbols in the support library (libsupc++) have their own tag.
 CXXABI_1.3 {
 
--- libstdc++-v3/config/abi/post/i386-linux-gnu/baseline_symbols.txt.jj	2013-03-16 08:09:37.423570786 +0100
+++ libstdc++-v3/config/abi/post/i386-linux-gnu/baseline_symbols.txt	2013-05-23 15:43:37.846877915 +0200
@@ -1938,6 +1938,8 @@ FUNC:_ZNSt6__norm15_List_node_base7rever
 FUNC:_ZNSt6__norm15_List_node_base8transferEPS0_S1_@@GLIBCXX_3.4.9
 FUNC:_ZNSt6__norm15_List_node_base9_M_unhookEv@@GLIBCXX_3.4.14
 FUNC:_ZNSt6chrono12system_clock3nowEv@@GLIBCXX_3.4.11
+FUNC:_ZNSt6chrono12steady_clock3nowEv@@GLIBCXX_3.4.19
+FUNC:_ZNSt6chrono12steady_clock3nowEv@GLIBCXX_3.4.17
 FUNC:_ZNSt6gslice8_IndexerC1EjRKSt8valarrayIjES4_@@GLIBCXX_3.4
 FUNC:_ZNSt6gslice8_IndexerC2EjRKSt8valarrayIjES4_@@GLIBCXX_3.4
 FUNC:_ZNSt6locale11_M_coalesceERKS_S1_i@@GLIBCXX_3.4
@@ -2514,6 +2516,7 @@ OBJECT:0:GLIBCXX_3.4.15
 OBJECT:0:GLIBCXX_3.4.16
 OBJECT:0:GLIBCXX_3.4.17
 OBJECT:0:GLIBCXX_3.4.18
+OBJECT:0:GLIBCXX_3.4.19
 OBJECT:0:GLIBCXX_3.4.2
 OBJECT:0:GLIBCXX_3.4.3
 OBJECT:0:GLIBCXX_3.4.4
--- libstdc++-v3/config/abi/post/s390x-linux-gnu/baseline_symbols.txt.jj	2013-03-16 08:09:36.882574033 +0100
+++ libstdc++-v3/config/abi/post/s390x-linux-gnu/baseline_symbols.txt	2013-05-23 15:45:51.432944873 +0200
@@ -2128,6 +2128,8 @@ FUNC:_ZNSt6__norm15_List_node_base7rever
 FUNC:_ZNSt6__norm15_List_node_base8transferEPS0_S1_@@GLIBCXX_3.4.9
 FUNC:_ZNSt6__norm15_List_node_base9_M_unhookEv@@GLIBCXX_3.4.14
 FUNC:_ZNSt6chrono12system_clock3nowEv@@GLIBCXX_3.4.11
+FUNC:_ZNSt6chrono12steady_clock3nowEv@@GLIBCXX_3.4.19
+FUNC:_ZNSt6chrono12steady_clock3nowEv@GLIBCXX_3.4.17
 FUNC:_ZNSt6gslice8_IndexerC1EmRKSt8valarrayImES4_@@GLIBCXX_3.4
 FUNC:_ZNSt6gslice8_IndexerC2EmRKSt8valarrayImES4_@@GLIBCXX_3.4
 FUNC:_ZNSt6locale11_M_coalesceERKS_S1_i@@GLIBCXX_3.4
@@ -2748,6 +2750,7 @@ OBJECT:0:GLIBCXX_3.4.15
 OBJECT:0:GLIBCXX_3.4.16
 OBJECT:0:GLIBCXX_3.4.17
 OBJECT:0:GLIBCXX_3.4.18
+OBJECT:0:GLIBCXX_3.4.19
 OBJECT:0:GLIBCXX_3.4.2
 OBJECT:0:GLIBCXX_3.4.3
 OBJECT:0:GLIBCXX_3.4.4
--- libstdc++-v3/config/abi/post/powerpc64-linux-gnu/baseline_symbols.txt.jj	2013-03-16 08:09:37.648569439 +0100
+++ libstdc++-v3/config/abi/post/powerpc64-linux-gnu/baseline_symbols.txt	2013-05-23 15:45:08.736291429 +0200
@@ -2128,6 +2128,8 @@ FUNC:_ZNSt6__norm15_List_node_base7rever
 FUNC:_ZNSt6__norm15_List_node_base8transferEPS0_S1_@@GLIBCXX_3.4.9
 FUNC:_ZNSt6__norm15_List_node_base9_M_unhookEv@@GLIBCXX_3.4.14
 FUNC:_ZNSt6chrono12system_clock3nowEv@@GLIBCXX_3.4.11
+FUNC:_ZNSt6chrono12steady_clock3nowEv@@GLIBCXX_3.4.19
+FUNC:_ZNSt6chrono12steady_clock3nowEv@GLIBCXX_3.4.17
 FUNC:_ZNSt6gslice8_IndexerC1EmRKSt8valarrayImES4_@@GLIBCXX_3.4
 FUNC:_ZNSt6gslice8_IndexerC2EmRKSt8valarrayImES4_@@GLIBCXX_3.4
 FUNC:_ZNSt6locale11_M_coalesceERKS_S1_i@@GLIBCXX_3.4
@@ -2748,6 +2750,7 @@ OBJECT:0:GLIBCXX_3.4.15
 OBJECT:0:GLIBCXX_3.4.16
 OBJECT:0:GLIBCXX_3.4.17
 OBJECT:0:GLIBCXX_3.4.18
+OBJECT:0:GLIBCXX_3.4.19
 OBJECT:0:GLIBCXX_3.4.2
 OBJECT:0:GLIBCXX_3.4.3
 OBJECT:0:GLIBCXX_3.4.4
--- libstdc++-v3/config/abi/post/powerpc64-linux-gnu/32/baseline_symbols.txt.jj	2013-03-16 08:09:37.489570393 +0100
+++ libstdc++-v3/config/abi/post/powerpc64-linux-gnu/32/baseline_symbols.txt	2013-05-23 15:45:13.783372530 +0200
@@ -2128,6 +2128,8 @@ FUNC:_ZNSt6__norm15_List_node_base7rever
 FUNC:_ZNSt6__norm15_List_node_base8transferEPS0_S1_@@GLIBCXX_3.4.9
 FUNC:_ZNSt6__norm15_List_node_base9_M_unhookEv@@GLIBCXX_3.4.14
 FUNC:_ZNSt6chrono12system_clock3nowEv@@GLIBCXX_3.4.11
+FUNC:_ZNSt6chrono12steady_clock3nowEv@@GLIBCXX_3.4.19
+FUNC:_ZNSt6chrono12steady_clock3nowEv@GLIBCXX_3.4.17
 FUNC:_ZNSt6gslice8_IndexerC1EjRKSt8valarrayIjES4_@@GLIBCXX_3.4
 FUNC:_ZNSt6gslice8_IndexerC2EjRKSt8valarrayIjES4_@@GLIBCXX_3.4
 FUNC:_ZNSt6locale11_M_coalesceERKS_S1_i@@GLIBCXX_3.4
@@ -2748,6 +2750,7 @@ OBJECT:0:GLIBCXX_3.4.15
 OBJECT:0:GLIBCXX_3.4.16
 OBJECT:0:GLIBCXX_3.4.17
 OBJECT:0:GLIBCXX_3.4.18
+OBJECT:0:GLIBCXX_3.4.19
 OBJECT:0:GLIBCXX_3.4.2
 OBJECT:0:GLIBCXX_3.4.3
 OBJECT:0:GLIBCXX_3.4.4
--- libstdc++-v3/config/abi/post/x86_64-linux-gnu/baseline_symbols.txt.jj	2013-03-16 08:09:36.000000000 +0100
+++ libstdc++-v3/config/abi/post/x86_64-linux-gnu/baseline_symbols.txt	2013-05-23 15:41:27.344826481 +0200
@@ -1938,6 +1938,8 @@ FUNC:_ZNSt6__norm15_List_node_base7rever
 FUNC:_ZNSt6__norm15_List_node_base8transferEPS0_S1_@@GLIBCXX_3.4.9
 FUNC:_ZNSt6__norm15_List_node_base9_M_unhookEv@@GLIBCXX_3.4.14
 FUNC:_ZNSt6chrono12system_clock3nowEv@@GLIBCXX_3.4.11
+FUNC:_ZNSt6chrono12steady_clock3nowEv@@GLIBCXX_3.4.19
+FUNC:_ZNSt6chrono12steady_clock3nowEv@GLIBCXX_3.4.17
 FUNC:_ZNSt6gslice8_IndexerC1EmRKSt8valarrayImES4_@@GLIBCXX_3.4
 FUNC:_ZNSt6gslice8_IndexerC2EmRKSt8valarrayImES4_@@GLIBCXX_3.4
 FUNC:_ZNSt6locale11_M_coalesceERKS_S1_i@@GLIBCXX_3.4
@@ -2514,6 +2516,7 @@ OBJECT:0:GLIBCXX_3.4.15
 OBJECT:0:GLIBCXX_3.4.16
 OBJECT:0:GLIBCXX_3.4.17
 OBJECT:0:GLIBCXX_3.4.18
+OBJECT:0:GLIBCXX_3.4.19
 OBJECT:0:GLIBCXX_3.4.2
 OBJECT:0:GLIBCXX_3.4.3
 OBJECT:0:GLIBCXX_3.4.4
--- libstdc++-v3/config/abi/post/x86_64-linux-gnu/32/baseline_symbols.txt.jj	2013-03-16 08:09:35.000000000 +0100
+++ libstdc++-v3/config/abi/post/x86_64-linux-gnu/32/baseline_symbols.txt	2013-05-23 15:41:36.474966903 +0200
@@ -1938,6 +1938,8 @@ FUNC:_ZNSt6__norm15_List_node_base7rever
 FUNC:_ZNSt6__norm15_List_node_base8transferEPS0_S1_@@GLIBCXX_3.4.9
 FUNC:_ZNSt6__norm15_List_node_base9_M_unhookEv@@GLIBCXX_3.4.14
 FUNC:_ZNSt6chrono12system_clock3nowEv@@GLIBCXX_3.4.11
+FUNC:_ZNSt6chrono12steady_clock3nowEv@@GLIBCXX_3.4.19
+FUNC:_ZNSt6chrono12steady_clock3nowEv@GLIBCXX_3.4.17
 FUNC:_ZNSt6gslice8_IndexerC1EjRKSt8valarrayIjES4_@@GLIBCXX_3.4
 FUNC:_ZNSt6gslice8_IndexerC2EjRKSt8valarrayIjES4_@@GLIBCXX_3.4
 FUNC:_ZNSt6locale11_M_coalesceERKS_S1_i@@GLIBCXX_3.4
@@ -2514,6 +2516,7 @@ OBJECT:0:GLIBCXX_3.4.15
 OBJECT:0:GLIBCXX_3.4.16
 OBJECT:0:GLIBCXX_3.4.17
 OBJECT:0:GLIBCXX_3.4.18
+OBJECT:0:GLIBCXX_3.4.19
 OBJECT:0:GLIBCXX_3.4.2
 OBJECT:0:GLIBCXX_3.4.3
 OBJECT:0:GLIBCXX_3.4.4
--- libstdc++-v3/config/abi/post/powerpc-linux-gnu/baseline_symbols.txt.jj	2013-03-16 08:09:36.175578273 +0100
+++ libstdc++-v3/config/abi/post/powerpc-linux-gnu/baseline_symbols.txt	2013-05-23 15:44:36.216771955 +0200
@@ -2128,6 +2128,8 @@ FUNC:_ZNSt6__norm15_List_node_base7rever
 FUNC:_ZNSt6__norm15_List_node_base8transferEPS0_S1_@@GLIBCXX_3.4.9
 FUNC:_ZNSt6__norm15_List_node_base9_M_unhookEv@@GLIBCXX_3.4.14
 FUNC:_ZNSt6chrono12system_clock3nowEv@@GLIBCXX_3.4.11
+FUNC:_ZNSt6chrono12steady_clock3nowEv@@GLIBCXX_3.4.19
+FUNC:_ZNSt6chrono12steady_clock3nowEv@GLIBCXX_3.4.17
 FUNC:_ZNSt6gslice8_IndexerC1EjRKSt8valarrayIjES4_@@GLIBCXX_3.4
 FUNC:_ZNSt6gslice8_IndexerC2EjRKSt8valarrayIjES4_@@GLIBCXX_3.4
 FUNC:_ZNSt6locale11_M_coalesceERKS_S1_i@@GLIBCXX_3.4
@@ -2748,6 +2750,7 @@ OBJECT:0:GLIBCXX_3.4.15
 OBJECT:0:GLIBCXX_3.4.16
 OBJECT:0:GLIBCXX_3.4.17
 OBJECT:0:GLIBCXX_3.4.18
+OBJECT:0:GLIBCXX_3.4.19
 OBJECT:0:GLIBCXX_3.4.2
 OBJECT:0:GLIBCXX_3.4.3
 OBJECT:0:GLIBCXX_3.4.4
--- libstdc++-v3/config/abi/post/s390-linux-gnu/baseline_symbols.txt.jj	2013-03-16 08:09:35.702581217 +0100
+++ libstdc++-v3/config/abi/post/s390-linux-gnu/baseline_symbols.txt	2013-05-23 15:45:32.397667896 +0200
@@ -2128,6 +2128,8 @@ FUNC:_ZNSt6__norm15_List_node_base7rever
 FUNC:_ZNSt6__norm15_List_node_base8transferEPS0_S1_@@GLIBCXX_3.4.9
 FUNC:_ZNSt6__norm15_List_node_base9_M_unhookEv@@GLIBCXX_3.4.14
 FUNC:_ZNSt6chrono12system_clock3nowEv@@GLIBCXX_3.4.11
+FUNC:_ZNSt6chrono12steady_clock3nowEv@@GLIBCXX_3.4.19
+FUNC:_ZNSt6chrono12steady_clock3nowEv@GLIBCXX_3.4.17
 FUNC:_ZNSt6gslice8_IndexerC1EmRKSt8valarrayImES4_@@GLIBCXX_3.4
 FUNC:_ZNSt6gslice8_IndexerC2EmRKSt8valarrayImES4_@@GLIBCXX_3.4
 FUNC:_ZNSt6locale11_M_coalesceERKS_S1_i@@GLIBCXX_3.4
@@ -2748,6 +2750,7 @@ OBJECT:0:GLIBCXX_3.4.15
 OBJECT:0:GLIBCXX_3.4.16
 OBJECT:0:GLIBCXX_3.4.17
 OBJECT:0:GLIBCXX_3.4.18
+OBJECT:0:GLIBCXX_3.4.19
 OBJECT:0:GLIBCXX_3.4.2
 OBJECT:0:GLIBCXX_3.4.3
 OBJECT:0:GLIBCXX_3.4.4
--- libstdc++-v3/config/abi/post/i486-linux-gnu/baseline_symbols.txt.jj	2013-03-16 08:09:38.030567148 +0100
+++ libstdc++-v3/config/abi/post/i486-linux-gnu/baseline_symbols.txt	2013-05-23 15:43:55.152138816 +0200
@@ -1938,6 +1938,8 @@ FUNC:_ZNSt6__norm15_List_node_base7rever
 FUNC:_ZNSt6__norm15_List_node_base8transferEPS0_S1_@@GLIBCXX_3.4.9
 FUNC:_ZNSt6__norm15_List_node_base9_M_unhookEv@@GLIBCXX_3.4.14
 FUNC:_ZNSt6chrono12system_clock3nowEv@@GLIBCXX_3.4.11
+FUNC:_ZNSt6chrono12steady_clock3nowEv@@GLIBCXX_3.4.19
+FUNC:_ZNSt6chrono12steady_clock3nowEv@GLIBCXX_3.4.17
 FUNC:_ZNSt6gslice8_IndexerC1EjRKSt8valarrayIjES4_@@GLIBCXX_3.4
 FUNC:_ZNSt6gslice8_IndexerC2EjRKSt8valarrayIjES4_@@GLIBCXX_3.4
 FUNC:_ZNSt6locale11_M_coalesceERKS_S1_i@@GLIBCXX_3.4
@@ -2514,6 +2516,7 @@ OBJECT:0:GLIBCXX_3.4.15
 OBJECT:0:GLIBCXX_3.4.16
 OBJECT:0:GLIBCXX_3.4.17
 OBJECT:0:GLIBCXX_3.4.18
+OBJECT:0:GLIBCXX_3.4.19
 OBJECT:0:GLIBCXX_3.4.2
 OBJECT:0:GLIBCXX_3.4.3
 OBJECT:0:GLIBCXX_3.4.4
--- libstdc++-v3/config.h.in.jj	2013-04-10 08:32:08.000000000 +0200
+++ libstdc++-v3/config.h.in	2013-05-23 14:10:35.000000000 +0200
@@ -813,6 +813,9 @@
 /* Defined if clock_gettime has monotonic clock support. */
 #undef _GLIBCXX_USE_CLOCK_MONOTONIC
 
+/* Defined if clock_gettime syscall has monotonic clock support. */
+#undef _GLIBCXX_USE_CLOCK_MONOTONIC_SYSCALL
+
 /* Defined if clock_gettime has realtime clock support. */
 #undef _GLIBCXX_USE_CLOCK_REALTIME
 
--- libstdc++-v3/src/Makefile.in.jj	2013-03-22 15:05:13.000000000 +0100
+++ libstdc++-v3/src/Makefile.in	2013-05-23 15:19:26.341768018 +0200
@@ -93,7 +93,7 @@ am__DEPENDENCIES_1 =
 am__objects_2 = compatibility.lo compatibility-debug_list.lo \
 	compatibility-debug_list-2.lo $(am__objects_1)
 am__objects_3 = compatibility-c++0x.lo compatibility-atomic-c++0x.lo \
-	compatibility-thread-c++0x.lo
+	compatibility-thread-c++0x.lo compatibility-chrono.lo
 am_libstdc___la_OBJECTS = $(am__objects_2) $(am__objects_3)
 libstdc___la_OBJECTS = $(am_libstdc___la_OBJECTS)
 DEFAULT_INCLUDES = -I.@am__isrc@ -I$(top_builddir)
@@ -351,7 +351,8 @@ cxx98_sources = \
 cxx11_sources = \
 	compatibility-c++0x.cc \
 	compatibility-atomic-c++0x.cc \
-	compatibility-thread-c++0x.cc
+	compatibility-thread-c++0x.cc \
+	compatibility-chrono.cc
 
 libstdc___la_SOURCES = $(cxx98_sources) $(cxx11_sources)
 libstdc___la_LIBADD = \
@@ -848,6 +849,11 @@ compatibility-thread-c++0x.lo: compatibi
 compatibility-thread-c++0x.o: compatibility-thread-c++0x.cc
 	$(CXXCOMPILE) -std=gnu++11 -c $<
 
+compatibility-chrono.lo: compatibility-chrono.cc
+	$(LTCXXCOMPILE) -std=gnu++11 -c $<
+compatibility-chrono.o: compatibility-chrono.cc
+	$(CXXCOMPILE) -std=gnu++11 -c $<
+
 # Symbol versioning for shared libraries.
 @ENABLE_SYMVERS_TRUE@libstdc++-symbols.ver:  ${glibcxx_srcdir}/$(SYMVER_FILE) \
 @ENABLE_SYMVERS_TRUE@		$(port_specific_symbol_files)
--- libstdc++-v3/configure.jj	2013-04-10 08:32:08.000000000 +0200
+++ libstdc++-v3/configure	2013-05-23 14:16:06.508039167 +0200
@@ -19828,6 +19828,48 @@ $as_echo "$ac_has_nanosleep" >&6; }
     fi
   fi
 
+  if test x"$ac_has_clock_monotonic" != x"yes"; then
+    case ${target_os} in
+      linux*)
+	{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for clock_gettime syscall" >&5
+$as_echo_n "checking for clock_gettime syscall... " >&6; }
+	cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <unistd.h>
+	   #include <time.h>
+	   #include <sys/syscall.h>
+
+int
+main ()
+{
+#if _POSIX_TIMERS > 0 && defined(_POSIX_MONOTONIC_CLOCK)
+	    timespec tp;
+	   #endif
+	   syscall(SYS_clock_gettime, CLOCK_MONOTONIC, &tp);
+	   syscall(SYS_clock_gettime, CLOCK_REALTIME, &tp);
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_cxx_try_compile "$LINENO"; then :
+  ac_has_clock_monotonic_syscall=yes
+else
+  ac_has_clock_monotonic_syscall=no
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+	{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_has_clock_monotonic_syscall" >&5
+$as_echo "$ac_has_clock_monotonic_syscall" >&6; }
+	if test x"$ac_has_clock_monotonic_syscall" = x"yes"; then
+
+$as_echo "#define _GLIBCXX_USE_CLOCK_MONOTONIC_SYSCALL 1" >>confdefs.h
+
+	  ac_has_clock_monotonic=yes
+	  ac_has_clock_realtime=yes
+	fi;;
+    esac
+  fi
+
   if test x"$ac_has_clock_monotonic" = x"yes"; then
 
 $as_echo "#define _GLIBCXX_USE_CLOCK_MONOTONIC 1" >>confdefs.h

Comments

Daniel Krügler May 24, 2013, 8:54 a.m. UTC | #1 
2013/5/24 Jakub Jelinek <jakub@redhat.com>:
> So, let's talk about other options, is constexpr/const on
> std::chrono::steady_clock::is_steady
> required by the standard (as in, could we export
> _ZNSt6chrono12steady_clock9is_steadyE@@GLIBCXX_3.4.19
> and let the library say which case it is, it would be constexpr when
> we know for sure, and a static variable otherwise)?
> But looking at C++11 draft, in [time.clock.steady]
> it even says that is_steady is true (then we are violating the standard
> even when we represent steady_clock as typedef system_clock steady_clock;).

Yes, steady_clock::is_steady needs to be true and to be usable within
constant expressions.

- Daniel
Rainer Orth May 24, 2013, 9 a.m. UTC | #2 
Jakub Jelinek <jakub@redhat.com> writes:

> On Thu, May 23, 2013 at 11:54:05PM +0200, Rainer Orth wrote:
>> > Agreed, that seems the best course of action if that's an option.
>> 
>> I just remembered that we aren't there yet even on mainline:
>> 
>> * This snippet
>> 
>>   http://gcc.gnu.org/ml/gcc-patches/2013-05/msg01255.html
>> 
>>   is necessary to avoid bootstrap failure on Solaris 9.
>> 
>> * We'll need to link every C++ program with -lrt on Solaris, as
>>   mentioned in the same message.  I suppose the best way to do this is
>>   along the lines of libgfortran.spec, rather than duplicate the
>>   necessary configury between g++ and libstdc++.  This might prove
>>   pretty invasive for the testsuite, though, and delay the 4.8.1 release
>>   quite a bit.
>
> Ugh, that makes =auto pretty much unbackportable, but it seems Solaris is
> the only problematic OS here.  The goal of
> _ZNSt6chrono12steady_clock3nowEv@@GLIBCXX_3.4.19
> already in 4.8.1 was to allow Linux users (and with partial backport of
> =auto not including Solaris perhaps also FreeBSD/NetBSD/OpenBSD) to let
> users that get C++ core language feature completeness also use this
> (Jonathan/Benjamin, is that right?).

It occured to me that there might be a far less intrusive option to still
allow a Solaris backport: instead of going the libstdc++.spec route
(which I still think is the correct way forward), statically handle -lrt
addition in g++spec.c, controlled by a macro defined only in config/sol2.h.

Such a patch could be added to mainline and 4.8 branch now, and mainline
later changed to use libstdc++.spec instead.

	Rainer
Jakub Jelinek May 24, 2013, 1:21 p.m. UTC | #3 
On Fri, May 24, 2013 at 11:00:26AM +0200, Rainer Orth wrote:
> Jakub Jelinek <jakub@redhat.com> writes:
> 
> > On Thu, May 23, 2013 at 11:54:05PM +0200, Rainer Orth wrote:
> >> > Agreed, that seems the best course of action if that's an option.
> >> 
> >> I just remembered that we aren't there yet even on mainline:
> >> 
> >> * This snippet
> >> 
> >>   http://gcc.gnu.org/ml/gcc-patches/2013-05/msg01255.html
> >> 
> >>   is necessary to avoid bootstrap failure on Solaris 9.
> >> 
> >> * We'll need to link every C++ program with -lrt on Solaris, as
> >>   mentioned in the same message.  I suppose the best way to do this is
> >>   along the lines of libgfortran.spec, rather than duplicate the
> >>   necessary configury between g++ and libstdc++.  This might prove
> >>   pretty invasive for the testsuite, though, and delay the 4.8.1 release
> >>   quite a bit.
> >
> > Ugh, that makes =auto pretty much unbackportable, but it seems Solaris is
> > the only problematic OS here.  The goal of
> > _ZNSt6chrono12steady_clock3nowEv@@GLIBCXX_3.4.19
> > already in 4.8.1 was to allow Linux users (and with partial backport of
> > =auto not including Solaris perhaps also FreeBSD/NetBSD/OpenBSD) to let
> > users that get C++ core language feature completeness also use this
> > (Jonathan/Benjamin, is that right?).
> 
> It occured to me that there might be a far less intrusive option to still
> allow a Solaris backport: instead of going the libstdc++.spec route
> (which I still think is the correct way forward), statically handle -lrt
> addition in g++spec.c, controlled by a macro defined only in config/sol2.h.
> 
> Such a patch could be added to mainline and 4.8 branch now, and mainline
> later changed to use libstdc++.spec instead.

I think a switch from not linking libstdc++ against -lrt to linking against
that is quite heavy change for the branch.  Do you see why the latest patch
I've posted today wouldn't work well on Solaris?

	Jakub
diff mbox

Patch

--- libstdc++-v3/src/c++11/chrono.cc.jj	2013-02-04 18:15:15.078395533 +0100
+++ libstdc++-v3/src/c++11/chrono.cc	2013-05-23 18:06:40.562825017 +0200
@@ -22,7 +22,20 @@ 
 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 // <http://www.gnu.org/licenses/>.
 
+#include <bits/c++config.h>
+
+#ifndef _GLIBCXX_USE_CLOCK_MONOTONIC
+// If !_GLIBCXX_USE_CLOCK_MONOTONIC, std::chrono::steady_clock
+// is just a typedef to std::chrono::system_clock, for ABI compatibility
+// force it not to be a typedef now and export it anyway.  Programs
+// using the headers where it is a typedef will actually just use
+// std::chrono::system_clock instead, and this remains here just as a fallback.
+#define _GLIBCXX_USE_CLOCK_MONOTONIC
+#include <chrono>
+#undef _GLIBCXX_USE_CLOCK_MONOTONIC
+#else
 #include <chrono>
+#endif
 
 #ifdef _GLIBCXX_USE_C99_STDINT_TR1
 
@@ -32,13 +45,18 @@ 
      defined(_GLIBCXX_USE_GETTIMEOFDAY)
 #include <sys/time.h>
 #endif
+#ifdef _GLIBCXX_USE_CLOCK_MONOTONIC_SYSCALL
+#include <unistd.h>
+#include <sys/syscall.h>
+#endif
 
 namespace std _GLIBCXX_VISIBILITY(default)
 {
   namespace chrono
   {
   _GLIBCXX_BEGIN_NAMESPACE_VERSION
- 
+
+#ifndef _GLIBCXX_COMPATIBILITY_CXX0X
     constexpr bool system_clock::is_steady;
 
     system_clock::time_point
@@ -47,7 +65,11 @@  namespace std _GLIBCXX_VISIBILITY(defaul
 #ifdef _GLIBCXX_USE_CLOCK_REALTIME
       timespec tp;
       // -EINVAL, -EFAULT
+#ifdef _GLIBCXX_USE_CLOCK_MONOTONIC_SYSCALL
+      syscall(SYS_clock_gettime, CLOCK_REALTIME, &tp);
+#else
       clock_gettime(CLOCK_REALTIME, &tp);
+#endif
       return time_point(duration(chrono::seconds(tp.tv_sec)
 				 + chrono::nanoseconds(tp.tv_nsec)));
 #elif defined(_GLIBCXX_USE_GETTIMEOFDAY)
@@ -61,20 +83,35 @@  namespace std _GLIBCXX_VISIBILITY(defaul
       return system_clock::from_time_t(__sec);
 #endif
     }
+#endif
     
-#ifdef _GLIBCXX_USE_CLOCK_MONOTONIC
+#ifndef _GLIBCXX_COMPATIBILITY_CXX0X
     constexpr bool steady_clock::is_steady;
+#endif
 
+#if defined(_GLIBCXX_SYMVER_GNU) && defined(_GLIBCXX_SHARED) \
+    && defined(_GLIBCXX_HAVE_AS_SYMVER_DIRECTIVE) \
+    && defined(_GLIBCXX_HAVE_SYMVER_SYMBOL_RENAMING_RUNTIME_SUPPORT) \
+    && !defined(_GLIBCXX_COMPATIBILITY_CXX0X)
+    __attribute__((__weak__))
+#endif
     steady_clock::time_point
     steady_clock::now() noexcept
     {
+#ifndef _GLIBCXX_USE_CLOCK_MONOTONIC
+      return chrono::system_clock::now ();
+#else
       timespec tp;
       // -EINVAL, -EFAULT
+#ifdef _GLIBCXX_USE_CLOCK_MONOTONIC_SYSCALL
+      syscall(SYS_clock_gettime, CLOCK_MONOTONIC, &tp);
+#else
       clock_gettime(CLOCK_MONOTONIC, &tp);
+#endif
       return time_point(duration(chrono::seconds(tp.tv_sec)
 				 + chrono::nanoseconds(tp.tv_nsec)));
-    }
 #endif
+    }
 
   _GLIBCXX_END_NAMESPACE_VERSION
   } // namespace chrono
--- libstdc++-v3/src/Makefile.am.jj	2013-02-14 20:11:41.491575233 +0100
+++ libstdc++-v3/src/Makefile.am	2013-05-23 18:06:40.578824061 +0200
@@ -50,7 +50,8 @@  cxx98_sources = \
 cxx11_sources = \
 	compatibility-c++0x.cc \
 	compatibility-atomic-c++0x.cc \
-	compatibility-thread-c++0x.cc
+	compatibility-thread-c++0x.cc \
+	compatibility-chrono.cc
 
 libstdc___la_SOURCES = $(cxx98_sources) $(cxx11_sources)
 
@@ -97,6 +98,11 @@  compatibility-thread-c++0x.lo: compatibi
 compatibility-thread-c++0x.o: compatibility-thread-c++0x.cc
 	$(CXXCOMPILE) -std=gnu++11 -c $<
 
+compatibility-chrono.lo: compatibility-chrono.cc
+	$(LTCXXCOMPILE) -std=gnu++11 -c $<
+compatibility-chrono.o: compatibility-chrono.cc
+	$(CXXCOMPILE) -std=gnu++11 -c $<
+
 # A note on compatibility and static libraries.
 # 
 # static lib == linked against only this version, should not need compat
--- libstdc++-v3/src/c++11/compatibility-chrono.cc.jj	2013-05-23 18:06:40.585823828 +0200
+++ libstdc++-v3/src/c++11/compatibility-chrono.cc	2013-05-23 18:06:40.585823828 +0200
@@ -0,0 +1,58 @@ 
+// Compatibility symbols for previous versions, C++0x bits -*- C++ -*-
+
+// Copyright (C) 2013 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/>.
+
+#define _GLIBCXX_COMPATIBILITY_CXX0X
+#include <bits/c++config.h>
+
+#if defined(_GLIBCXX_SYMVER_GNU) && defined(_GLIBCXX_SHARED) \
+    && defined(_GLIBCXX_HAVE_AS_SYMVER_DIRECTIVE)\
+    && defined(_GLIBCXX_HAVE_SYMVER_SYMBOL_RENAMING_RUNTIME_SUPPORT)
+
+#define steady_clock steady_clockXX
+#include "chrono.cc"
+
+// The rename syntax for default exported names is
+//   asm (".symver name1,exportedname@GLIBCXX_3.4.17")
+//   asm (".symver name2,exportedname@@GLIBCXX_3.4.19")
+// In the future, GLIBCXX_ABI > 6 should remove all uses of
+// _GLIBCXX_*_SYMVER macros in this file.
+
+#define _GLIBCXX_3_4_17_SYMVER(XXname, name) \
+   extern "C" void \
+   _X##name() \
+   __attribute__ ((alias(#XXname))); \
+   asm (".symver " "_X" #name "," #name "@GLIBCXX_3.4.17");
+
+#define _GLIBCXX_3_4_19_SYMVER(XXname, name) \
+   extern "C" void \
+   _Y##name() \
+   __attribute__ ((alias(#XXname))); \
+   asm (".symver " "_Y" #name  "," #name "@@GLIBCXX_3.4.19");
+
+_GLIBCXX_3_4_17_SYMVER(_ZNSt6chrono14steady_clockXX3nowEv,
+		       _ZNSt6chrono12steady_clock3nowEv)
+_GLIBCXX_3_4_19_SYMVER(_ZNSt6chrono14steady_clockXX3nowEv,
+		       _ZNSt6chrono12steady_clock3nowEv)
+
+#endif
--- libstdc++-v3/acinclude.m4.jj	2013-05-23 18:06:19.841949134 +0200
+++ libstdc++-v3/acinclude.m4	2013-05-23 18:06:40.586823808 +0200
@@ -1322,6 +1322,31 @@  AC_DEFUN([GLIBCXX_ENABLE_LIBSTDCXX_TIME]
     fi
   fi
 
+  if test x"$ac_has_clock_monotonic" != x"yes"; then
+    case ${target_os} in
+      linux*)
+	AC_MSG_CHECKING([for clock_gettime syscall])
+	AC_TRY_COMPILE(
+	  [#include <unistd.h>
+	   #include <time.h>
+	   #include <sys/syscall.h>
+	  ],
+	  [#if _POSIX_TIMERS > 0 && defined(_POSIX_MONOTONIC_CLOCK)
+	    timespec tp;
+	   #endif
+	   syscall(SYS_clock_gettime, CLOCK_MONOTONIC, &tp);
+	   syscall(SYS_clock_gettime, CLOCK_REALTIME, &tp);
+	  ], [ac_has_clock_monotonic_syscall=yes], [ac_has_clock_monotonic_syscall=no])
+	AC_MSG_RESULT($ac_has_clock_monotonic_syscall)
+	if test x"$ac_has_clock_monotonic_syscall" = x"yes"; then
+	  AC_DEFINE(_GLIBCXX_USE_CLOCK_MONOTONIC_SYSCALL, 1,
+	  [ Defined if clock_gettime syscall has monotonic clock support. ])
+	  ac_has_clock_monotonic=yes
+	  ac_has_clock_realtime=yes
+	fi;;
+    esac
+  fi
+
   if test x"$ac_has_clock_monotonic" = x"yes"; then
     AC_DEFINE(_GLIBCXX_USE_CLOCK_MONOTONIC, 1,
       [ Defined if clock_gettime has monotonic clock support. ])
--- libstdc++-v3/testsuite/util/testsuite_abi.cc.jj	2013-05-10 10:36:28.000000000 +0200
+++ libstdc++-v3/testsuite/util/testsuite_abi.cc	2013-05-23 18:12:15.933965878 +0200
@@ -199,6 +199,7 @@  check_version(symbol& test, bool added)
       known_versions.push_back("GLIBCXX_3.4.17");
       known_versions.push_back("GLIBCXX_3.4.18");
       known_versions.push_back("GLIBCXX_3.4.19");
+      known_versions.push_back("GLIBCXX_3.4.20");
       known_versions.push_back("CXXABI_1.3");
       known_versions.push_back("CXXABI_LDBL_1.3");
       known_versions.push_back("CXXABI_1.3.1");
@@ -225,7 +226,7 @@  check_version(symbol& test, bool added)
 	test.version_status = symbol::incompatible;
 
       // Check that added symbols are added in the latest pre-release version.
-      bool latestp = (test.version_name == "GLIBCXX_3.4.19"
+      bool latestp = (test.version_name == "GLIBCXX_3.4.20"
 		     || test.version_name == "CXXABI_1.3.8"
 		     || test.version_name == "CXXABI_TM_1");
       if (added && !latestp)
--- libstdc++-v3/config/abi/pre/gnu.ver.jj	2013-05-10 10:36:28.640688086 +0200
+++ libstdc++-v3/config/abi/pre/gnu.ver	2013-05-23 18:11:51.087096178 +0200
@@ -1303,9 +1303,6 @@  GLIBCXX_3.4.17 {
     _ZN11__gnu_debug25_Safe_local_iterator_base9_M_attachEPNS_19_Safe_sequence_baseEb;
     _ZN11__gnu_debug25_Safe_local_iterator_base9_M_detachEv;
 
-    # std::chrono::steady_clock::now()
-    _ZNSt6chrono12steady_clock3nowEv;
-
     # std::numeric_limits<__int128> and <unsigned __int128>
     _ZNSt14numeric_limitsInE*;
     _ZNSt14numeric_limitsIoE*;
@@ -1323,6 +1320,12 @@  GLIBCXX_3.4.17 {
     _ZNSt13__future_base19_Async_state_commonD1Ev;
     _ZNSt13__future_base19_Async_state_commonD2Ev;
 
+#ifdef HAVE_SYMVER_SYMBOL_RENAMING_RUNTIME_SUPPORT
+   # GLIBCXX_ABI compatibility only.
+    # std::chrono::steady_clock::now()
+    _ZNSt6chrono12steady_clock3nowEv;
+#endif
+
 } GLIBCXX_3.4.16;
 
 GLIBCXX_3.4.18 {
@@ -1345,6 +1345,13 @@  GLIBCXX_3.4.18 {
 } GLIBCXX_3.4.17;
 
 GLIBCXX_3.4.19 {
+
+    # std::chrono::steady_clock::now()
+    _ZNSt6chrono12steady_clock3nowEv;
+
+} GLIBCXX_3.4.18;
+
+GLIBCXX_3.4.20 {
 
     # std::get_new_handler()
     _ZSt15get_new_handlerv;
@@ -1355,7 +1360,7 @@  GLIBCXX_3.4.19 {
     # std::get_unexpected()
     _ZSt14get_unexpectedv;
 
-} GLIBCXX_3.4.18;
+} GLIBCXX_3.4.19;
 
 # Symbols in the support library (libsupc++) have their own tag.
 CXXABI_1.3 {
--- libstdc++-v3/config/abi/post/i386-linux-gnu/baseline_symbols.txt.jj	2013-03-07 16:47:15.756981144 +0100
+++ libstdc++-v3/config/abi/post/i386-linux-gnu/baseline_symbols.txt	2013-05-23 18:06:40.635823435 +0200
@@ -1938,6 +1938,8 @@  FUNC:_ZNSt6__norm15_List_node_base7rever
 FUNC:_ZNSt6__norm15_List_node_base8transferEPS0_S1_@@GLIBCXX_3.4.9
 FUNC:_ZNSt6__norm15_List_node_base9_M_unhookEv@@GLIBCXX_3.4.14
 FUNC:_ZNSt6chrono12system_clock3nowEv@@GLIBCXX_3.4.11
+FUNC:_ZNSt6chrono12steady_clock3nowEv@@GLIBCXX_3.4.19
+FUNC:_ZNSt6chrono12steady_clock3nowEv@GLIBCXX_3.4.17
 FUNC:_ZNSt6gslice8_IndexerC1EjRKSt8valarrayIjES4_@@GLIBCXX_3.4
 FUNC:_ZNSt6gslice8_IndexerC2EjRKSt8valarrayIjES4_@@GLIBCXX_3.4
 FUNC:_ZNSt6locale11_M_coalesceERKS_S1_i@@GLIBCXX_3.4
@@ -2514,6 +2516,7 @@  OBJECT:0:GLIBCXX_3.4.15
 OBJECT:0:GLIBCXX_3.4.16
 OBJECT:0:GLIBCXX_3.4.17
 OBJECT:0:GLIBCXX_3.4.18
+OBJECT:0:GLIBCXX_3.4.19
 OBJECT:0:GLIBCXX_3.4.2
 OBJECT:0:GLIBCXX_3.4.3
 OBJECT:0:GLIBCXX_3.4.4
--- libstdc++-v3/config/abi/post/s390x-linux-gnu/baseline_symbols.txt.jj	2013-03-07 16:47:15.917980229 +0100
+++ libstdc++-v3/config/abi/post/s390x-linux-gnu/baseline_symbols.txt	2013-05-23 18:06:40.662823272 +0200
@@ -2128,6 +2128,8 @@  FUNC:_ZNSt6__norm15_List_node_base7rever
 FUNC:_ZNSt6__norm15_List_node_base8transferEPS0_S1_@@GLIBCXX_3.4.9
 FUNC:_ZNSt6__norm15_List_node_base9_M_unhookEv@@GLIBCXX_3.4.14
 FUNC:_ZNSt6chrono12system_clock3nowEv@@GLIBCXX_3.4.11
+FUNC:_ZNSt6chrono12steady_clock3nowEv@@GLIBCXX_3.4.19
+FUNC:_ZNSt6chrono12steady_clock3nowEv@GLIBCXX_3.4.17
 FUNC:_ZNSt6gslice8_IndexerC1EmRKSt8valarrayImES4_@@GLIBCXX_3.4
 FUNC:_ZNSt6gslice8_IndexerC2EmRKSt8valarrayImES4_@@GLIBCXX_3.4
 FUNC:_ZNSt6locale11_M_coalesceERKS_S1_i@@GLIBCXX_3.4
@@ -2748,6 +2750,7 @@  OBJECT:0:GLIBCXX_3.4.15
 OBJECT:0:GLIBCXX_3.4.16
 OBJECT:0:GLIBCXX_3.4.17
 OBJECT:0:GLIBCXX_3.4.18
+OBJECT:0:GLIBCXX_3.4.19
 OBJECT:0:GLIBCXX_3.4.2
 OBJECT:0:GLIBCXX_3.4.3
 OBJECT:0:GLIBCXX_3.4.4
--- libstdc++-v3/config/abi/post/powerpc64-linux-gnu/baseline_symbols.txt.jj	2013-03-07 16:47:15.871980491 +0100
+++ libstdc++-v3/config/abi/post/powerpc64-linux-gnu/baseline_symbols.txt	2013-05-23 18:06:40.689823108 +0200
@@ -2128,6 +2128,8 @@  FUNC:_ZNSt6__norm15_List_node_base7rever
 FUNC:_ZNSt6__norm15_List_node_base8transferEPS0_S1_@@GLIBCXX_3.4.9
 FUNC:_ZNSt6__norm15_List_node_base9_M_unhookEv@@GLIBCXX_3.4.14
 FUNC:_ZNSt6chrono12system_clock3nowEv@@GLIBCXX_3.4.11
+FUNC:_ZNSt6chrono12steady_clock3nowEv@@GLIBCXX_3.4.19
+FUNC:_ZNSt6chrono12steady_clock3nowEv@GLIBCXX_3.4.17
 FUNC:_ZNSt6gslice8_IndexerC1EmRKSt8valarrayImES4_@@GLIBCXX_3.4
 FUNC:_ZNSt6gslice8_IndexerC2EmRKSt8valarrayImES4_@@GLIBCXX_3.4
 FUNC:_ZNSt6locale11_M_coalesceERKS_S1_i@@GLIBCXX_3.4
@@ -2748,6 +2750,7 @@  OBJECT:0:GLIBCXX_3.4.15
 OBJECT:0:GLIBCXX_3.4.16
 OBJECT:0:GLIBCXX_3.4.17
 OBJECT:0:GLIBCXX_3.4.18
+OBJECT:0:GLIBCXX_3.4.19
 OBJECT:0:GLIBCXX_3.4.2
 OBJECT:0:GLIBCXX_3.4.3
 OBJECT:0:GLIBCXX_3.4.4
--- libstdc++-v3/config/abi/post/powerpc64-linux-gnu/32/baseline_symbols.txt.jj	2013-03-07 16:47:15.847980627 +0100
+++ libstdc++-v3/config/abi/post/powerpc64-linux-gnu/32/baseline_symbols.txt	2013-05-23 18:06:40.717822939 +0200
@@ -2128,6 +2128,8 @@  FUNC:_ZNSt6__norm15_List_node_base7rever
 FUNC:_ZNSt6__norm15_List_node_base8transferEPS0_S1_@@GLIBCXX_3.4.9
 FUNC:_ZNSt6__norm15_List_node_base9_M_unhookEv@@GLIBCXX_3.4.14
 FUNC:_ZNSt6chrono12system_clock3nowEv@@GLIBCXX_3.4.11
+FUNC:_ZNSt6chrono12steady_clock3nowEv@@GLIBCXX_3.4.19
+FUNC:_ZNSt6chrono12steady_clock3nowEv@GLIBCXX_3.4.17
 FUNC:_ZNSt6gslice8_IndexerC1EjRKSt8valarrayIjES4_@@GLIBCXX_3.4
 FUNC:_ZNSt6gslice8_IndexerC2EjRKSt8valarrayIjES4_@@GLIBCXX_3.4
 FUNC:_ZNSt6locale11_M_coalesceERKS_S1_i@@GLIBCXX_3.4
@@ -2748,6 +2750,7 @@  OBJECT:0:GLIBCXX_3.4.15
 OBJECT:0:GLIBCXX_3.4.16
 OBJECT:0:GLIBCXX_3.4.17
 OBJECT:0:GLIBCXX_3.4.18
+OBJECT:0:GLIBCXX_3.4.19
 OBJECT:0:GLIBCXX_3.4.2
 OBJECT:0:GLIBCXX_3.4.3
 OBJECT:0:GLIBCXX_3.4.4
--- libstdc++-v3/config/abi/post/x86_64-linux-gnu/baseline_symbols.txt.jj	2013-03-07 16:47:16.001979751 +0100
+++ libstdc++-v3/config/abi/post/x86_64-linux-gnu/baseline_symbols.txt	2013-05-23 18:06:40.739822806 +0200
@@ -1938,6 +1938,8 @@  FUNC:_ZNSt6__norm15_List_node_base7rever
 FUNC:_ZNSt6__norm15_List_node_base8transferEPS0_S1_@@GLIBCXX_3.4.9
 FUNC:_ZNSt6__norm15_List_node_base9_M_unhookEv@@GLIBCXX_3.4.14
 FUNC:_ZNSt6chrono12system_clock3nowEv@@GLIBCXX_3.4.11
+FUNC:_ZNSt6chrono12steady_clock3nowEv@@GLIBCXX_3.4.19
+FUNC:_ZNSt6chrono12steady_clock3nowEv@GLIBCXX_3.4.17
 FUNC:_ZNSt6gslice8_IndexerC1EmRKSt8valarrayImES4_@@GLIBCXX_3.4
 FUNC:_ZNSt6gslice8_IndexerC2EmRKSt8valarrayImES4_@@GLIBCXX_3.4
 FUNC:_ZNSt6locale11_M_coalesceERKS_S1_i@@GLIBCXX_3.4
@@ -2514,6 +2516,7 @@  OBJECT:0:GLIBCXX_3.4.15
 OBJECT:0:GLIBCXX_3.4.16
 OBJECT:0:GLIBCXX_3.4.17
 OBJECT:0:GLIBCXX_3.4.18
+OBJECT:0:GLIBCXX_3.4.19
 OBJECT:0:GLIBCXX_3.4.2
 OBJECT:0:GLIBCXX_3.4.3
 OBJECT:0:GLIBCXX_3.4.4
--- libstdc++-v3/config/abi/post/x86_64-linux-gnu/32/baseline_symbols.txt.jj	2013-03-07 16:47:15.953980024 +0100
+++ libstdc++-v3/config/abi/post/x86_64-linux-gnu/32/baseline_symbols.txt	2013-05-23 18:06:40.763822661 +0200
@@ -1938,6 +1938,8 @@  FUNC:_ZNSt6__norm15_List_node_base7rever
 FUNC:_ZNSt6__norm15_List_node_base8transferEPS0_S1_@@GLIBCXX_3.4.9
 FUNC:_ZNSt6__norm15_List_node_base9_M_unhookEv@@GLIBCXX_3.4.14
 FUNC:_ZNSt6chrono12system_clock3nowEv@@GLIBCXX_3.4.11
+FUNC:_ZNSt6chrono12steady_clock3nowEv@@GLIBCXX_3.4.19
+FUNC:_ZNSt6chrono12steady_clock3nowEv@GLIBCXX_3.4.17
 FUNC:_ZNSt6gslice8_IndexerC1EjRKSt8valarrayIjES4_@@GLIBCXX_3.4
 FUNC:_ZNSt6gslice8_IndexerC2EjRKSt8valarrayIjES4_@@GLIBCXX_3.4
 FUNC:_ZNSt6locale11_M_coalesceERKS_S1_i@@GLIBCXX_3.4
@@ -2514,6 +2516,7 @@  OBJECT:0:GLIBCXX_3.4.15
 OBJECT:0:GLIBCXX_3.4.16
 OBJECT:0:GLIBCXX_3.4.17
 OBJECT:0:GLIBCXX_3.4.18
+OBJECT:0:GLIBCXX_3.4.19
 OBJECT:0:GLIBCXX_3.4.2
 OBJECT:0:GLIBCXX_3.4.3
 OBJECT:0:GLIBCXX_3.4.4
--- libstdc++-v3/config/abi/post/powerpc-linux-gnu/baseline_symbols.txt.jj	2013-03-07 16:47:15.884980416 +0100
+++ libstdc++-v3/config/abi/post/powerpc-linux-gnu/baseline_symbols.txt	2013-05-23 18:06:40.782822546 +0200
@@ -2128,6 +2128,8 @@  FUNC:_ZNSt6__norm15_List_node_base7rever
 FUNC:_ZNSt6__norm15_List_node_base8transferEPS0_S1_@@GLIBCXX_3.4.9
 FUNC:_ZNSt6__norm15_List_node_base9_M_unhookEv@@GLIBCXX_3.4.14
 FUNC:_ZNSt6chrono12system_clock3nowEv@@GLIBCXX_3.4.11
+FUNC:_ZNSt6chrono12steady_clock3nowEv@@GLIBCXX_3.4.19
+FUNC:_ZNSt6chrono12steady_clock3nowEv@GLIBCXX_3.4.17
 FUNC:_ZNSt6gslice8_IndexerC1EjRKSt8valarrayIjES4_@@GLIBCXX_3.4
 FUNC:_ZNSt6gslice8_IndexerC2EjRKSt8valarrayIjES4_@@GLIBCXX_3.4
 FUNC:_ZNSt6locale11_M_coalesceERKS_S1_i@@GLIBCXX_3.4
@@ -2748,6 +2750,7 @@  OBJECT:0:GLIBCXX_3.4.15
 OBJECT:0:GLIBCXX_3.4.16
 OBJECT:0:GLIBCXX_3.4.17
 OBJECT:0:GLIBCXX_3.4.18
+OBJECT:0:GLIBCXX_3.4.19
 OBJECT:0:GLIBCXX_3.4.2
 OBJECT:0:GLIBCXX_3.4.3
 OBJECT:0:GLIBCXX_3.4.4
--- libstdc++-v3/config/abi/post/s390-linux-gnu/baseline_symbols.txt.jj	2013-03-07 16:47:15.892980371 +0100
+++ libstdc++-v3/config/abi/post/s390-linux-gnu/baseline_symbols.txt	2013-05-23 18:06:40.792822486 +0200
@@ -2128,6 +2128,8 @@  FUNC:_ZNSt6__norm15_List_node_base7rever
 FUNC:_ZNSt6__norm15_List_node_base8transferEPS0_S1_@@GLIBCXX_3.4.9
 FUNC:_ZNSt6__norm15_List_node_base9_M_unhookEv@@GLIBCXX_3.4.14
 FUNC:_ZNSt6chrono12system_clock3nowEv@@GLIBCXX_3.4.11
+FUNC:_ZNSt6chrono12steady_clock3nowEv@@GLIBCXX_3.4.19
+FUNC:_ZNSt6chrono12steady_clock3nowEv@GLIBCXX_3.4.17
 FUNC:_ZNSt6gslice8_IndexerC1EmRKSt8valarrayImES4_@@GLIBCXX_3.4
 FUNC:_ZNSt6gslice8_IndexerC2EmRKSt8valarrayImES4_@@GLIBCXX_3.4
 FUNC:_ZNSt6locale11_M_coalesceERKS_S1_i@@GLIBCXX_3.4
@@ -2748,6 +2750,7 @@  OBJECT:0:GLIBCXX_3.4.15
 OBJECT:0:GLIBCXX_3.4.16
 OBJECT:0:GLIBCXX_3.4.17
 OBJECT:0:GLIBCXX_3.4.18
+OBJECT:0:GLIBCXX_3.4.19
 OBJECT:0:GLIBCXX_3.4.2
 OBJECT:0:GLIBCXX_3.4.3
 OBJECT:0:GLIBCXX_3.4.4
--- libstdc++-v3/config/abi/post/i486-linux-gnu/baseline_symbols.txt.jj	2013-03-07 16:47:15.807980856 +0100
+++ libstdc++-v3/config/abi/post/i486-linux-gnu/baseline_symbols.txt	2013-05-23 18:06:40.806822401 +0200
@@ -1938,6 +1938,8 @@  FUNC:_ZNSt6__norm15_List_node_base7rever
 FUNC:_ZNSt6__norm15_List_node_base8transferEPS0_S1_@@GLIBCXX_3.4.9
 FUNC:_ZNSt6__norm15_List_node_base9_M_unhookEv@@GLIBCXX_3.4.14
 FUNC:_ZNSt6chrono12system_clock3nowEv@@GLIBCXX_3.4.11
+FUNC:_ZNSt6chrono12steady_clock3nowEv@@GLIBCXX_3.4.19
+FUNC:_ZNSt6chrono12steady_clock3nowEv@GLIBCXX_3.4.17
 FUNC:_ZNSt6gslice8_IndexerC1EjRKSt8valarrayIjES4_@@GLIBCXX_3.4
 FUNC:_ZNSt6gslice8_IndexerC2EjRKSt8valarrayIjES4_@@GLIBCXX_3.4
 FUNC:_ZNSt6locale11_M_coalesceERKS_S1_i@@GLIBCXX_3.4
@@ -2514,6 +2516,7 @@  OBJECT:0:GLIBCXX_3.4.15
 OBJECT:0:GLIBCXX_3.4.16
 OBJECT:0:GLIBCXX_3.4.17
 OBJECT:0:GLIBCXX_3.4.18
+OBJECT:0:GLIBCXX_3.4.19
 OBJECT:0:GLIBCXX_3.4.2
 OBJECT:0:GLIBCXX_3.4.3
 OBJECT:0:GLIBCXX_3.4.4
--- libstdc++-v3/config.h.in.jj	2013-04-10 08:32:04.601960092 +0200
+++ libstdc++-v3/config.h.in	2013-05-23 18:06:40.828822268 +0200
@@ -813,6 +813,9 @@ 
 /* Defined if clock_gettime has monotonic clock support. */
 #undef _GLIBCXX_USE_CLOCK_MONOTONIC
 
+/* Defined if clock_gettime syscall has monotonic clock support. */
+#undef _GLIBCXX_USE_CLOCK_MONOTONIC_SYSCALL
+
 /* Defined if clock_gettime has realtime clock support. */
 #undef _GLIBCXX_USE_CLOCK_REALTIME
 
--- libstdc++-v3/src/Makefile.in.jj	2013-02-14 20:11:41.438575540 +0100
+++ libstdc++-v3/src/Makefile.in	2013-05-23 18:06:40.844822172 +0200
@@ -93,7 +93,7 @@  am__DEPENDENCIES_1 =
 am__objects_2 = compatibility.lo compatibility-debug_list.lo \
 	compatibility-debug_list-2.lo $(am__objects_1)
 am__objects_3 = compatibility-c++0x.lo compatibility-atomic-c++0x.lo \
-	compatibility-thread-c++0x.lo
+	compatibility-thread-c++0x.lo compatibility-chrono.lo
 am_libstdc___la_OBJECTS = $(am__objects_2) $(am__objects_3)
 libstdc___la_OBJECTS = $(am_libstdc___la_OBJECTS)
 DEFAULT_INCLUDES = -I.@am__isrc@ -I$(top_builddir)
@@ -351,7 +351,8 @@  cxx98_sources = \
 cxx11_sources = \
 	compatibility-c++0x.cc \
 	compatibility-atomic-c++0x.cc \
-	compatibility-thread-c++0x.cc
+	compatibility-thread-c++0x.cc \
+	compatibility-chrono.cc
 
 libstdc___la_SOURCES = $(cxx98_sources) $(cxx11_sources)
 libstdc___la_LIBADD = \
@@ -848,6 +849,11 @@  compatibility-thread-c++0x.lo: compatibi
 compatibility-thread-c++0x.o: compatibility-thread-c++0x.cc
 	$(CXXCOMPILE) -std=gnu++11 -c $<
 
+compatibility-chrono.lo: compatibility-chrono.cc
+	$(LTCXXCOMPILE) -std=gnu++11 -c $<
+compatibility-chrono.o: compatibility-chrono.cc
+	$(CXXCOMPILE) -std=gnu++11 -c $<
+
 # Symbol versioning for shared libraries.
 @ENABLE_SYMVERS_TRUE@libstdc++-symbols.ver:  ${glibcxx_srcdir}/$(SYMVER_FILE) \
 @ENABLE_SYMVERS_TRUE@		$(port_specific_symbol_files)
--- libstdc++-v3/configure.jj	2013-05-23 18:06:19.685950078 +0200
+++ libstdc++-v3/configure	2013-05-23 18:06:40.862822063 +0200
@@ -19883,6 +19883,48 @@  $as_echo "$ac_has_nanosleep" >&6; }
     fi
   fi
 
+  if test x"$ac_has_clock_monotonic" != x"yes"; then
+    case ${target_os} in
+      linux*)
+	{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for clock_gettime syscall" >&5
+$as_echo_n "checking for clock_gettime syscall... " >&6; }
+	cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <unistd.h>
+	   #include <time.h>
+	   #include <sys/syscall.h>
+
+int
+main ()
+{
+#if _POSIX_TIMERS > 0 && defined(_POSIX_MONOTONIC_CLOCK)
+	    timespec tp;
+	   #endif
+	   syscall(SYS_clock_gettime, CLOCK_MONOTONIC, &tp);
+	   syscall(SYS_clock_gettime, CLOCK_REALTIME, &tp);
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_cxx_try_compile "$LINENO"; then :
+  ac_has_clock_monotonic_syscall=yes
+else
+  ac_has_clock_monotonic_syscall=no
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+	{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_has_clock_monotonic_syscall" >&5
+$as_echo "$ac_has_clock_monotonic_syscall" >&6; }
+	if test x"$ac_has_clock_monotonic_syscall" = x"yes"; then
+
+$as_echo "#define _GLIBCXX_USE_CLOCK_MONOTONIC_SYSCALL 1" >>confdefs.h
+
+	  ac_has_clock_monotonic=yes
+	  ac_has_clock_realtime=yes
+	fi;;
+    esac
+  fi
+
   if test x"$ac_has_clock_monotonic" = x"yes"; then
 
 $as_echo "#define _GLIBCXX_USE_CLOCK_MONOTONIC 1" >>confdefs.h