Partially address a FIXME in steady_clock::now()

http://reviews.llvm.org/D4045

llvm-svn: 216949

libcxx/include/__config

@@ -650,6 +650,11 @@ template <unsigned> struct __static_assert_check {};
 #  define _LIBCPP_TRIVIAL_PAIR_COPY_CTOR 1
 #endif
 
+#if (!defined(_POSIX_TIMERS) || _POSIX_TIMERS <= 0) || \
+    (!defined(_POSIX_MONOTONIC_CLOCK) || _POSIX_MONOTONIC_CLOCK <= 0)
+#define _LIBCPP_HAS_NO_MONOTONIC_CLOCK
+#endif
+
 #ifndef _LIBCPP_STD_VER
 #  if  __cplusplus <= 201103L
 #    define _LIBCPP_STD_VER 11

libcxx/include/chrono

@@ -926,6 +926,7 @@ public:
     static time_point from_time_t(time_t __t) _NOEXCEPT;
 };
 
+#ifndef _LIBCPP_HAS_NO_MONOTONIC_CLOCK
 class _LIBCPP_TYPE_VIS steady_clock
 {
 public:
@@ -939,6 +940,9 @@ public:
 };
 
 typedef steady_clock high_resolution_clock;
+#else
+typedef system_clock high_resolution_clock;
+#endif
 
 } // chrono
 

libcxx/src/chrono.cpp

@@ -46,6 +46,7 @@ system_clock::from_time_t(time_t t) _NOEXCEPT
     return system_clock::time_point(seconds(t));
 }
 
+#ifndef _LIBCPP_HAS_NO_MONOTONIC_CLOCK
 // steady_clock
 
 const bool steady_clock::is_steady;
@@ -127,6 +128,8 @@ steady_clock::now() _NOEXCEPT
 }
 #endif  // __APPLE__
 
+#endif // !_LIBCPP_HAS_NO_MONOTONIC_CLOCK
+
 }
 
 _LIBCPP_END_NAMESPACE_STD

libcxx/test/utilities/time/time.clock/time.clock.steady/consistency.pass.cpp

@@ -11,6 +11,7 @@
 // darwin11 and darwin12:
 // XFAIL: with_system_lib=x86_64-apple-darwin11
 // XFAIL: with_system_lib=x86_64-apple-darwin12
+// UNSUPPORTED: no-monotonic-clock
 
 // <chrono>
 

libcxx/test/utilities/time/time.clock/time.clock.steady/now.pass.cpp

@@ -6,6 +6,8 @@
 // Source Licenses. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
+//
+// UNSUPPORTED: no-monotonic-clock
 
 // <chrono>