https://gcc.gnu.org/g:806de30f51c8b959d031b375ec13343c20b864cf
commit r16-3416-g806de30f51c8b959d031b375ec13343c20b864cf
Author: Nathan Myers <n...@cantrip.org>
Date: Wed Aug 20 20:24:29 2025 -0400
libstdc++: Move tai_- and gps_clock::now impls out of ABI
This patch moves std::tai_clock::now() and std::tai_clock::now()
definitions from header inlines to static members invoked via a
normal function call, in service of stabilizing the C++20 ABI.
It also changes #if guards to mention the actual __cpp_lib_*
feature gated, not just the language version, for clarity.
New global function symbols std::chrono::tai_clock::now
and std::chrono::gps_clock::now are exported.
libstdc++-v3/ChangeLog:
* include/std/chrono (gps_clock::now, tai_clock::now): Remove
inline definitions.
* src/c++20/clock.cc (gps_clock::now, tai_clock::now): New file
for out-of-line now() impls.
* src/c++20/Makefile.am: Mention clock.cc.
* src/c++20/Makefile.in: Regenerate.
* config/abi/pre/gnu.ver: add mangled now() symbols.
Diff:
---
libstdc++-v3/config/abi/pre/gnu.ver | 4 +++
libstdc++-v3/include/std/chrono | 32 +++++++++++------------
libstdc++-v3/src/c++20/Makefile.am | 2 +-
libstdc++-v3/src/c++20/Makefile.in | 4 +--
libstdc++-v3/src/c++20/clock.cc | 52 +++++++++++++++++++++++++++++++++++++
5 files changed, 74 insertions(+), 20 deletions(-)
diff --git a/libstdc++-v3/config/abi/pre/gnu.ver
b/libstdc++-v3/config/abi/pre/gnu.ver
index b5a89c31e0eb..e1601dc39d25 100644
--- a/libstdc++-v3/config/abi/pre/gnu.ver
+++ b/libstdc++-v3/config/abi/pre/gnu.ver
@@ -2555,6 +2555,10 @@ GLIBCXX_3.4.35 {
_ZNSt8__detail17__wait_until_implEPKvRNS_16__wait_args_baseERKNSt6chrono8durationI[lx]St5ratioIL[lx]1EL[lx]1000000000EEEE;
_ZNSt8__detail11__wait_args22_M_load_proxy_wait_valEPKv;
+ # std::chrono::gps_clock::now, tai_clock::now
+ _ZNSt6chrono9gps_clock3nowEv;
+ _ZNSt6chrono9tai_clock3nowEv;
+
# __gnu_debug::_Safe_iterator_base and _Safe_sequence_base const
_ZN11__gnu_debug19_Safe_iterator_base9_M_attachEPKNS_19_Safe_sequence_baseEb;
_ZN11__gnu_debug19_Safe_iterator_base16_M_attach_singleEPKNS_19_Safe_sequence_baseEb;
diff --git a/libstdc++-v3/include/std/chrono b/libstdc++-v3/include/std/chrono
index cb8213e2f9f9..d1a01fbdf0a8 100644
--- a/libstdc++-v3/include/std/chrono
+++ b/libstdc++-v3/include/std/chrono
@@ -22,6 +22,8 @@
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
+// [time]
+
/** @file include/chrono
* This is a Standard C++ Library header.
* @ingroup chrono
@@ -42,12 +44,16 @@
# include <bits/c++0x_warning.h>
#else
+#define __glibcxx_want_chrono
+#define __glibcxx_want_chrono_udls
+#include <bits/version.h>
+
#include <bits/chrono.h>
-#if __cplusplus >= 202002L
+#if __cpp_lib_bitops >= 201907L
# include <bit> // __countr_zero
#endif
-#if __cplusplus >= 202002L && _GLIBCXX_HOSTED
+#if __cpp_lib_chrono >= 201803L && _GLIBCXX_HOSTED
# include <sstream>
# include <string>
# include <vector>
@@ -56,10 +62,6 @@
# include <bits/unique_ptr.h>
#endif
-#define __glibcxx_want_chrono
-#define __glibcxx_want_chrono_udls
-#include <bits/version.h>
-
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
@@ -79,7 +81,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
*/
namespace chrono
{
-#if __cplusplus >= 202002L
+#if __cpp_lib_chrono >= 201803L
/// @addtogroup chrono
/// @{
struct local_t { };
@@ -175,13 +177,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
using period = system_clock::period;
using duration = chrono::duration<rep, period>;
using time_point = chrono::time_point<tai_clock>;
- static constexpr bool is_steady = false; // XXX true for CLOCK_TAI?
+ static constexpr bool is_steady = false;
- // TODO move into lib, use CLOCK_TAI on linux, add extension point.
[[nodiscard]]
static time_point
- now()
- { return from_utc(utc_clock::now()); }
+ now(); // in src/c++20/clock.cc
template<typename _Duration>
[[nodiscard]]
@@ -215,13 +215,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
using period = system_clock::period;
using duration = chrono::duration<rep, period>;
using time_point = chrono::time_point<gps_clock>;
- static constexpr bool is_steady = false; // XXX
+ static constexpr bool is_steady = false;
- // TODO move into lib, add extension point.
[[nodiscard]]
static time_point
- now()
- { return from_utc(utc_clock::now()); }
+ now(); // in src/c++20/clock.cc
template<typename _Duration>
[[nodiscard]]
@@ -3321,7 +3319,7 @@ namespace __detail
#endif // C++20
} // namespace chrono
-#if __cplusplus >= 202002L
+#if __cpp_lib_chrono >= 201803L
inline namespace literals
{
inline namespace chrono_literals
@@ -3350,7 +3348,7 @@ namespace __detail
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
-#if __cplusplus >= 202002L && _GLIBCXX_HOSTED
+#if __cpp_lib_chrono >= 201803L && _GLIBCXX_HOSTED
# include <bits/chrono_io.h>
#endif
diff --git a/libstdc++-v3/src/c++20/Makefile.am
b/libstdc++-v3/src/c++20/Makefile.am
index 15e6f3445fb6..736558ff24a7 100644
--- a/libstdc++-v3/src/c++20/Makefile.am
+++ b/libstdc++-v3/src/c++20/Makefile.am
@@ -36,7 +36,7 @@ else
inst_sources =
endif
-sources = tzdb.cc format.cc atomic.cc
+sources = tzdb.cc format.cc atomic.cc clock.cc
vpath % $(top_srcdir)/src/c++20
diff --git a/libstdc++-v3/src/c++20/Makefile.in
b/libstdc++-v3/src/c++20/Makefile.in
index d9e1615bbca8..3cb6d6fea5f3 100644
--- a/libstdc++-v3/src/c++20/Makefile.in
+++ b/libstdc++-v3/src/c++20/Makefile.in
@@ -121,7 +121,7 @@ CONFIG_CLEAN_FILES =
CONFIG_CLEAN_VPATH_FILES =
LTLIBRARIES = $(noinst_LTLIBRARIES)
libc__20convenience_la_LIBADD =
-am__objects_1 = tzdb.lo format.lo atomic.lo
+am__objects_1 = tzdb.lo format.lo atomic.lo clock.lo
@ENABLE_EXTERN_TEMPLATE_TRUE@am__objects_2 = sstream-inst.lo
@GLIBCXX_HOSTED_TRUE@am_libc__20convenience_la_OBJECTS = \
@GLIBCXX_HOSTED_TRUE@ $(am__objects_1) $(am__objects_2)
@@ -432,7 +432,7 @@ headers =
@ENABLE_EXTERN_TEMPLATE_TRUE@inst_sources = \
@ENABLE_EXTERN_TEMPLATE_TRUE@ sstream-inst.cc
-sources = tzdb.cc format.cc atomic.cc
+sources = tzdb.cc format.cc atomic.cc clock.cc
@GLIBCXX_HOSTED_FALSE@libc__20convenience_la_SOURCES =
@GLIBCXX_HOSTED_TRUE@libc__20convenience_la_SOURCES = $(sources)
$(inst_sources)
diff --git a/libstdc++-v3/src/c++20/clock.cc b/libstdc++-v3/src/c++20/clock.cc
new file mode 100644
index 000000000000..9d674b0b46a2
--- /dev/null
+++ b/libstdc++-v3/src/c++20/clock.cc
@@ -0,0 +1,52 @@
+// std::chrono::tai_clock, gps_clock
+
+// Copyright (C) 2021-2025 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++ 14882:2020
+// 27.7.4 [time.clock.tai], 27.7.5 [time.clock.gps]
+// P0355R7
+
+#include <chrono>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+namespace chrono
+{
+#if __cpp_lib_chrono >= 201803L && _GLIBCXX_HOSTED
+ // TODO use CLOCK_TAI on linux, add extension point.
+ time_point<tai_clock>
+ tai_clock::now()
+ { return from_utc(utc_clock::now()); }
+
+ // TODO add extension point.
+ time_point<gps_clock>
+ gps_clock::now()
+ { return from_utc(utc_clock::now()); }
+#endif
+}
+
+_GLIBCXX_END_NAMESPACE_VERSION
+}
