diff options
Diffstat (limited to 'libcxx/src/chrono.cpp')
| -rw-r--r-- | libcxx/src/chrono.cpp | 55 |
1 files changed, 0 insertions, 55 deletions
diff --git a/libcxx/src/chrono.cpp b/libcxx/src/chrono.cpp index 0af89d6a526c..8c85d96e5444 100644 --- a/libcxx/src/chrono.cpp +++ b/libcxx/src/chrono.cpp @@ -167,59 +167,6 @@ system_clock::from_time_t(time_t t) noexcept #if defined(__APPLE__) -// TODO(ldionne): -// This old implementation of steady_clock is retained until Chrome drops supports -// for macOS < 10.12. The issue is that they link libc++ statically into their -// application, which means that libc++ must support being built for such deployment -// targets. See https://llvm.org/D74489 for details. -#if (defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 101200) || \ - (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ < 100000) || \ - (defined(__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__ < 100000) || \ - (defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__ < 30000) -# define _LIBCPP_USE_OLD_MACH_ABSOLUTE_TIME -#endif - -#if defined(_LIBCPP_USE_OLD_MACH_ABSOLUTE_TIME) - -// mach_absolute_time() * MachInfo.numer / MachInfo.denom is the number of -// nanoseconds since the computer booted up. MachInfo.numer and MachInfo.denom -// are run time constants supplied by the OS. This clock has no relationship -// to the Gregorian calendar. It's main use is as a high resolution timer. - -// MachInfo.numer / MachInfo.denom is often 1 on the latest equipment. Specialize -// for that case as an optimization. - -static steady_clock::rep steady_simplified() { - return static_cast<steady_clock::rep>(mach_absolute_time()); -} -static double compute_steady_factor() { - mach_timebase_info_data_t MachInfo; - mach_timebase_info(&MachInfo); - return static_cast<double>(MachInfo.numer) / MachInfo.denom; -} - -static steady_clock::rep steady_full() { - static const double factor = compute_steady_factor(); - return static_cast<steady_clock::rep>(mach_absolute_time() * factor); -} - -typedef steady_clock::rep (*FP)(); - -static FP init_steady_clock() { - mach_timebase_info_data_t MachInfo; - mach_timebase_info(&MachInfo); - if (MachInfo.numer == MachInfo.denom) - return &steady_simplified; - return &steady_full; -} - -static steady_clock::time_point __libcpp_steady_clock_now() { - static FP fp = init_steady_clock(); - return steady_clock::time_point(steady_clock::duration(fp())); -} - -#else // vvvvv default behavior for Apple platforms vvvvv - // On Apple platforms, only CLOCK_UPTIME_RAW, CLOCK_MONOTONIC_RAW or // mach_absolute_time are able to time functions in the nanosecond range. // Furthermore, only CLOCK_MONOTONIC_RAW is truly monotonic, because it @@ -232,8 +179,6 @@ static steady_clock::time_point __libcpp_steady_clock_now() { return steady_clock::time_point(seconds(tp.tv_sec) + nanoseconds(tp.tv_nsec)); } -#endif - #elif defined(_LIBCPP_WIN32API) // https://msdn.microsoft.com/en-us/library/windows/desktop/ms644905(v=vs.85).aspx says: |