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libstdc++: Fix build failure for target with no way to sleep

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In previous releases the std::this_thread::sleep_for function was only
declared if the target supports multiple threads. I changed that
recently in r11-2649-g5bbb1f3000c57fd4d95969b30fa0e35be6d54ffb so that
sleep_for could be used single-threaded. But that means that targets
using --disable-threads are now required to provide some way to sleep.
This breaks the build for (at least) AVR when trying to build a hosted
library.

This patch adds a new autoconf macro that is defined when no way to
sleep is available, and uses that to suppress the sleeping functions in
std::this_thread.

The #error in src/c++11/thread.cc is retained for the case where there
is no sleep function available but multiple threads are supported. This
is consistent with previous releases, but that #error could probably be
removed without any consequences.

libstdc++-v3/ChangeLog:

	* acinclude.m4 (GLIBCXX_ENABLE_LIBSTDCXX_TIME): Define NO_SLEEP
	if none of nanosleep, sleep and Sleep is available.
	* config.h.in: Regenerate.
	* configure: Regenerate.
	* include/std/thread [_GLIBCXX_NO_SLEEP] (__sleep_for): Do
	not declare.
	[_GLIBCXX_NO_SLEEP] (sleep_for, sleep_until): Do not
	define.
	* src/c++11/thread.cc [_GLIBCXX_NO_SLEEP] (__sleep_for): Do
	not define.
This commit is contained in:
Jonathan Wakely 2020-12-09 16:53:18 +00:00
parent 84d08255f9
commit 0aa1786d34
5 changed files with 27 additions and 2 deletions
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6
libstdc++-v3/acinclude.m4
View file

@ -1626,16 +1626,22 @@ AC_DEFUN([GLIBCXX_ENABLE_LIBSTDCXX_TIME], [
fi
if test x"$ac_has_nanosleep$ac_has_sleep" = x"nono"; then
ac_no_sleep=yes
AC_MSG_CHECKING([for Sleep])
AC_TRY_COMPILE([#include <windows.h>],
[Sleep(1)],
[ac_has_win32_sleep=yes],[ac_has_win32_sleep=no])
if test x"$ac_has_win32_sleep" = x"yes"; then
AC_DEFINE(HAVE_WIN32_SLEEP,1, [Defined if Sleep exists.])
ac_no_sleep=no
fi
AC_MSG_RESULT($ac_has_win32_sleep)
fi
if test x"$ac_no_sleep" = x"yes"; then
AC_DEFINE(NO_SLEEP,1, [Defined if no way to sleep is available.])
fi
AC_SUBST(GLIBCXX_LIBS)
CXXFLAGS="$ac_save_CXXFLAGS"

3
libstdc++-v3/config.h.in
View file

@ -767,6 +767,9 @@
*/
#undef LT_OBJDIR
/* Defined if no way to sleep is available. */
#undef NO_SLEEP
/* Name of package */
#undef PACKAGE

8
libstdc++-v3/configure vendored
View file

@ -21751,6 +21751,7 @@ $as_echo "$ac_has_usleep" >&6; }
fi
if test x"$ac_has_nanosleep$ac_has_sleep" = x"nono"; then
ac_no_sleep=yes
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for Sleep" >&5
$as_echo_n "checking for Sleep... " >&6; }
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
@ -21774,11 +21775,18 @@ rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
$as_echo "#define HAVE_WIN32_SLEEP 1" >>confdefs.h
ac_no_sleep=no
fi
{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_has_win32_sleep" >&5
$as_echo "$ac_has_win32_sleep" >&6; }
fi
if test x"$ac_no_sleep" = x"yes"; then
$as_echo "#define NO_SLEEP 1" >>confdefs.h
fi
CXXFLAGS="$ac_save_CXXFLAGS"

7
libstdc++-v3/include/std/thread
View file

@ -122,8 +122,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
*/
namespace this_thread
{
#ifndef _GLIBCXX_NO_SLEEP
#ifndef _GLIBCXX_USE_NANOSLEEP
void
__sleep_for(chrono::seconds, chrono::nanoseconds);
#endif
/// this_thread::sleep_for
template<typename _Rep, typename _Period>
@ -168,7 +172,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__now = _Clock::now();
}
}
}
} // namespace this_thread
#endif // ! NO_SLEEP
#ifdef __cpp_lib_jthread

5
libstdc++-v3/src/c++11/thread.cc
View file

@ -35,7 +35,8 @@
# include <unistd.h>
# elif defined(_GLIBCXX_HAVE_WIN32_SLEEP)
# include <windows.h>
# else
# elif defined _GLIBCXX_NO_SLEEP && defined _GLIBCXX_HAS_GTHREADS
// We expect to be able to sleep for targets that support multiple threads:
# error "No sleep function known for this target"
# endif
#endif
@ -196,6 +197,7 @@ _GLIBCXX_END_NAMESPACE_VERSION
#endif // _GLIBCXX_HAS_GTHREADS
#ifndef _GLIBCXX_NO_SLEEP
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
@ -252,3 +254,4 @@ namespace this_thread
}
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
#endif // ! NO_SLEEP