1//===----------------------------------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#if defined(__MVS__)
10// As part of monotonic clock support on z/OS we need macro _LARGE_TIME_API
11// to be defined before any system header to include definition of struct timespec64.
12# define _LARGE_TIME_API
13#endif
14
15#include <__system_error/throw_system_error.h>
16#include <cerrno> // errno
17#include <chrono>
18
19#if defined(__MVS__)
20# include <__support/ibm/gettod_zos.h> // gettimeofdayMonotonic
21#endif
22
23#include "include/apple_availability.h"
24#include <time.h> // clock_gettime and CLOCK_{MONOTONIC,REALTIME,MONOTONIC_RAW}
25
26#if __has_include(<unistd.h>)
27# include <unistd.h> // _POSIX_TIMERS
28#endif
29
30#if __has_include(<sys/time.h>)
31# include <sys/time.h> // for gettimeofday and timeval
32#endif
33
34#if defined(__LLVM_LIBC__)
35# define _LIBCPP_HAS_TIMESPEC_GET
36#endif
37
38// OpenBSD and GPU do not have a fully conformant suite of POSIX timers, but
39// it does have clock_gettime and CLOCK_MONOTONIC which is all we need.
40#if defined(__APPLE__) || defined(__gnu_hurd__) || defined(__OpenBSD__) || defined(__AMDGPU__) || \
41 defined(__NVPTX__) || (defined(_POSIX_TIMERS) && _POSIX_TIMERS > 0)
42# define _LIBCPP_HAS_CLOCK_GETTIME
43#endif
44
45#if defined(_LIBCPP_WIN32API)
46# define WIN32_LEAN_AND_MEAN
47# define VC_EXTRA_LEAN
48# include <windows.h>
49# if _WIN32_WINNT >= _WIN32_WINNT_WIN8
50# include <winapifamily.h>
51# endif
52#endif // defined(_LIBCPP_WIN32API)
53
54#if defined(__Fuchsia__)
55# include <zircon/syscalls.h>
56#endif
57
58#if __has_include(<mach/mach_time.h>)
59# include <mach/mach_time.h>
60#endif
61
62#if defined(__ELF__) && defined(_LIBCPP_LINK_RT_LIB)
63# pragma comment(lib, "rt")
64#endif
65
66_LIBCPP_BEGIN_NAMESPACE_STD
67
68namespace chrono {
69
70//
71// system_clock
72//
73
74#if defined(_LIBCPP_WIN32API)
75
76# if _WIN32_WINNT < _WIN32_WINNT_WIN8
77
78namespace {
79
80typedef void(WINAPI* GetSystemTimeAsFileTimePtr)(LPFILETIME);
81
82class GetSystemTimeInit {
83public:
84 GetSystemTimeInit() {
85 fp = (GetSystemTimeAsFileTimePtr)(void*)GetProcAddress(
86 GetModuleHandleW(L"kernel32.dll"), "GetSystemTimePreciseAsFileTime");
87 if (fp == nullptr)
88 fp = GetSystemTimeAsFileTime;
89 }
90 GetSystemTimeAsFileTimePtr fp;
91};
92
93// Pretend we're inside a system header so the compiler doesn't flag the use of the init_priority
94// attribute with a value that's reserved for the implementation (we're the implementation).
95# include "chrono_system_time_init.h"
96} // namespace
97
98# endif
99
100static system_clock::time_point __libcpp_system_clock_now() {
101 // FILETIME is in 100ns units
102 using filetime_duration =
103 std::chrono::duration<__int64, std::ratio_multiply<std::ratio<100, 1>, nanoseconds::period>>;
104
105 // The Windows epoch is Jan 1 1601, the Unix epoch Jan 1 1970.
106 static constexpr const seconds nt_to_unix_epoch{11644473600};
107
108 FILETIME ft;
109# if (_WIN32_WINNT >= _WIN32_WINNT_WIN8 && WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)) || \
110 (_WIN32_WINNT >= _WIN32_WINNT_WIN10)
111 GetSystemTimePreciseAsFileTime(&ft);
112# elif !WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
113 GetSystemTimeAsFileTime(&ft);
114# else
115 GetSystemTimeAsFileTimeFunc.fp(&ft);
116# endif
117
118 filetime_duration d{(static_cast<__int64>(ft.dwHighDateTime) << 32) | static_cast<__int64>(ft.dwLowDateTime)};
119 return system_clock::time_point(duration_cast<system_clock::duration>(d - nt_to_unix_epoch));
120}
121
122#elif defined(_LIBCPP_HAS_TIMESPEC_GET)
123
124static system_clock::time_point __libcpp_system_clock_now() {
125 struct timespec ts;
126 if (timespec_get(&ts, TIME_UTC) != TIME_UTC)
127 std::__throw_system_error(errno, "timespec_get(TIME_UTC) failed");
128 return system_clock::time_point(seconds(ts.tv_sec) + microseconds(ts.tv_nsec / 1000));
129}
130
131#elif defined(_LIBCPP_HAS_CLOCK_GETTIME)
132
133static system_clock::time_point __libcpp_system_clock_now() {
134 struct timespec tp;
135 if (0 != clock_gettime(CLOCK_REALTIME, tp: &tp))
136 std::__throw_system_error(errno, what_arg: "clock_gettime(CLOCK_REALTIME) failed");
137 return system_clock::time_point(seconds(tp.tv_sec) + microseconds(tp.tv_nsec / 1000));
138}
139
140#else
141
142static system_clock::time_point __libcpp_system_clock_now() {
143 timeval tv;
144 gettimeofday(&tv, 0);
145 return system_clock::time_point(seconds(tv.tv_sec) + microseconds(tv.tv_usec));
146}
147
148#endif
149
150_LIBCPP_DIAGNOSTIC_PUSH
151_LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wdeprecated")
152const bool system_clock::is_steady;
153_LIBCPP_DIAGNOSTIC_POP
154
155system_clock::time_point system_clock::now() noexcept { return __libcpp_system_clock_now(); }
156
157time_t system_clock::to_time_t(const time_point& t) noexcept {
158 return time_t(duration_cast<seconds>(fd: t.time_since_epoch()).count());
159}
160
161system_clock::time_point system_clock::from_time_t(time_t t) noexcept { return system_clock::time_point(seconds(t)); }
162
163//
164// steady_clock
165//
166// Warning: If this is not truly steady, then it is non-conforming. It is
167// better for it to not exist and have the rest of libc++ use system_clock
168// instead.
169//
170
171#if _LIBCPP_HAS_MONOTONIC_CLOCK
172
173# if defined(__APPLE__)
174
175// On Apple platforms, only CLOCK_UPTIME_RAW, CLOCK_MONOTONIC_RAW or
176// mach_absolute_time are able to time functions in the nanosecond range.
177// Furthermore, only CLOCK_MONOTONIC_RAW is truly monotonic, because it
178// also counts cycles when the system is asleep. Thus, it is the only
179// acceptable implementation of steady_clock.
180static steady_clock::time_point __libcpp_steady_clock_now() {
181 struct timespec tp;
182 if (0 != clock_gettime(CLOCK_MONOTONIC_RAW, &tp))
183 std::__throw_system_error(errno, "clock_gettime(CLOCK_MONOTONIC_RAW) failed");
184 return steady_clock::time_point(seconds(tp.tv_sec) + nanoseconds(tp.tv_nsec));
185}
186
187# elif defined(_LIBCPP_WIN32API)
188
189// https://msdn.microsoft.com/en-us/library/windows/desktop/ms644905(v=vs.85).aspx says:
190// If the function fails, the return value is zero. <snip>
191// On systems that run Windows XP or later, the function will always succeed
192// and will thus never return zero.
193
194static LARGE_INTEGER __QueryPerformanceFrequency() {
195 LARGE_INTEGER val;
196 (void)QueryPerformanceFrequency(&val);
197 return val;
198}
199
200static steady_clock::time_point __libcpp_steady_clock_now() {
201 static const LARGE_INTEGER freq = __QueryPerformanceFrequency();
202
203 LARGE_INTEGER counter;
204 (void)QueryPerformanceCounter(&counter);
205 auto seconds = counter.QuadPart / freq.QuadPart;
206 auto fractions = counter.QuadPart % freq.QuadPart;
207 auto dur = seconds * nano::den + fractions * nano::den / freq.QuadPart;
208 return steady_clock::time_point(steady_clock::duration(dur));
209}
210
211# elif defined(__MVS__)
212
213static steady_clock::time_point __libcpp_steady_clock_now() {
214 struct timespec64 ts;
215 if (0 != gettimeofdayMonotonic(&ts))
216 std::__throw_system_error(errno, "failed to obtain time of day");
217
218 return steady_clock::time_point(seconds(ts.tv_sec) + nanoseconds(ts.tv_nsec));
219}
220
221# elif defined(__Fuchsia__)
222
223static steady_clock::time_point __libcpp_steady_clock_now() noexcept {
224 // Implicitly link against the vDSO system call ABI without
225 // requiring the final link to specify -lzircon explicitly when
226 // statically linking libc++.
227# pragma comment(lib, "zircon")
228
229 return steady_clock::time_point(nanoseconds(_zx_clock_get_monotonic()));
230}
231
232# elif defined(_LIBCPP_HAS_TIMESPEC_GET)
233
234static steady_clock::time_point __libcpp_steady_clock_now() {
235 struct timespec ts;
236 if (timespec_get(&ts, TIME_MONOTONIC) != TIME_MONOTONIC)
237 std::__throw_system_error(errno, "timespec_get(TIME_MONOTONIC) failed");
238 return steady_clock::time_point(seconds(ts.tv_sec) + microseconds(ts.tv_nsec / 1000));
239}
240
241# elif defined(_LIBCPP_HAS_CLOCK_GETTIME)
242
243static steady_clock::time_point __libcpp_steady_clock_now() {
244 struct timespec tp;
245 if (0 != clock_gettime(CLOCK_MONOTONIC, tp: &tp))
246 std::__throw_system_error(errno, what_arg: "clock_gettime(CLOCK_MONOTONIC) failed");
247 return steady_clock::time_point(seconds(tp.tv_sec) + nanoseconds(tp.tv_nsec));
248}
249
250# else
251# error "Monotonic clock not implemented on this platform"
252# endif
253
254_LIBCPP_DIAGNOSTIC_PUSH
255_LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wdeprecated")
256const bool steady_clock::is_steady;
257_LIBCPP_DIAGNOSTIC_POP
258
259steady_clock::time_point steady_clock::now() noexcept { return __libcpp_steady_clock_now(); }
260
261#endif // _LIBCPP_HAS_MONOTONIC_CLOCK
262
263} // namespace chrono
264
265_LIBCPP_END_NAMESPACE_STD
266