libstdc++: Make std::this_thread functions work without gthreads

The only function in namespace std::this_thread that actually depends on
thread support being present is this_thread::get_id(). The other
functions (yield, sleep_for and sleep_until) can be defined for targets
without gthreads.

A small change is needed in std::this_thread::sleep_for which currently
uses the __gthread_time_t typedef. Since it just calls nanosleep
directly, it should use timespec directly instead of the typedef.

Even std::this_thread::get_id() could be made to work, the only
difficulty is that it returns a value of type std::thread::id and
std::thread is only defined when gthreads support exists.

libstdc++-v3/ChangeLog:

	* include/std/thread [!_GLIBCXX_HAS_GTHREADS] (this_thread::yield)
	(this_thread::sleep_until): Define.
	[!_GLIBCXX_HAS_GTHREADS] (this_thread::sleep_for): Define. Replace
	use of __gthread_time_t typedef with timespec.
	* src/c++11/thread.cc [!_GLIBCXX_HAS_GTHREADS] (__sleep_for):
	Likewise.
	* testsuite/30_threads/this_thread/2.cc: Moved to...
	* testsuite/30_threads/this_thread/yield.cc: ...here.
	* testsuite/30_threads/this_thread/3.cc: Moved to...
	* testsuite/30_threads/this_thread/sleep_for-mt.cc: ...here.
	* testsuite/30_threads/this_thread/4.cc: Moved to...
	* testsuite/30_threads/this_thread/sleep_until-mt.cc: ...here.
	* testsuite/30_threads/this_thread/58038.cc: Add
	dg-require-sleep.
	* testsuite/30_threads/this_thread/60421.cc: Likewise.
	* testsuite/30_threads/this_thread/sleep_for.cc: New test.
	* testsuite/30_threads/this_thread/sleep_until.cc: New test.

1 files changed, 19 insertions, 14 deletions

diff --git a/libstdc++-v3/src/c++11/thread.cc b/libstdc++-v3/src/c++11/thread.cc
index 2d87817..a4c87d8 100644
--- a/libstdc++-v3/src/c++11/thread.cc
+++ b/libstdc++-v3/src/c++11/thread.cc
@@ -29,6 +29,16 @@
 #include <cerrno>
 #include <cxxabi_forced.h>
 
+#ifndef _GLIBCXX_USE_NANOSLEEP
+# ifdef _GLIBCXX_HAVE_SLEEP
+#  include <unistd.h>
+# elif defined(_GLIBCXX_HAVE_WIN32_SLEEP)
+#  include <windows.h>
+# else
+#  error "No sleep function known for this target"
+# endif
+#endif
+
 #ifdef _GLIBCXX_HAS_GTHREADS
 
 #if defined(_GLIBCXX_USE_GET_NPROCS)
@@ -59,16 +69,6 @@ static inline int get_nprocs()
 # define _GLIBCXX_NPROCS 0
 #endif
 
-#ifndef _GLIBCXX_USE_NANOSLEEP
-# ifdef _GLIBCXX_HAVE_SLEEP
-#  include <unistd.h>
-# elif defined(_GLIBCXX_HAVE_WIN32_SLEEP)
-#  include <windows.h>
-# else
-#  error "No sleep function known for this target"
-# endif
-#endif
-
 namespace std _GLIBCXX_VISIBILITY(default)
 {
   extern "C"
@@ -180,13 +180,21 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     return __n;
   }
 
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif // _GLIBCXX_HAS_GTHREADS
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
 namespace this_thread
 {
   void
   __sleep_for(chrono::seconds __s, chrono::nanoseconds __ns)
   {
 #ifdef _GLIBCXX_USE_NANOSLEEP
-    __gthread_time_t __ts =
+    struct ::timespec __ts =
       {
 	static_cast<std::time_t>(__s.count()),
 	static_cast<long>(__ns.count())
@@ -231,8 +239,5 @@ namespace this_thread
 #endif
   }
 }
-
 _GLIBCXX_END_NAMESPACE_VERSION
 } // namespace std
-
-#endif // _GLIBCXX_HAS_GTHREADS