aboutsummaryrefslogtreecommitdiffstats
path: root/contrib/libs/cxxsupp/libcxx/src/chrono.cpp
blob: 0af89d6a526c4cbfe698694b5b05828e14e0058b (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#if defined(__MVS__)
// As part of monotonic clock support on z/OS we need macro _LARGE_TIME_API
// to be defined before any system header to include definition of struct timespec64.
#define _LARGE_TIME_API
#endif

#include <cerrno>        // errno
#include <chrono>
#include <system_error>  // __throw_system_error

#if defined(__MVS__)
#include <__support/ibm/gettod_zos.h> // gettimeofdayMonotonic
#endif

#include <time.h>        // clock_gettime and CLOCK_{MONOTONIC,REALTIME,MONOTONIC_RAW}
#include "include/apple_availability.h"

#if __has_include(<unistd.h>)
# include <unistd.h>
#endif

#if __has_include(<sys/time.h>)
# include <sys/time.h> // for gettimeofday and timeval
#endif

#if !defined(__APPLE__) && defined(_POSIX_TIMERS) && _POSIX_TIMERS > 0
# define _LIBCPP_USE_CLOCK_GETTIME
#endif

#if defined(_LIBCPP_WIN32API)
#  define WIN32_LEAN_AND_MEAN
#  define VC_EXTRA_LEAN
#  include <windows.h>
#  if _WIN32_WINNT >= _WIN32_WINNT_WIN8
#    include <winapifamily.h>
#  endif
#endif // defined(_LIBCPP_WIN32API)

#if defined(__Fuchsia__)
#  include <zircon/syscalls.h>
#endif

#if __has_include(<mach/mach_time.h>)
# include <mach/mach_time.h>
#endif

#if defined(__ELF__) && defined(_LIBCPP_LINK_RT_LIB)
#  pragma comment(lib, "rt")
#endif

_LIBCPP_BEGIN_NAMESPACE_STD

namespace chrono
{

//
// system_clock
//

#if defined(_LIBCPP_WIN32API)

#if _WIN32_WINNT < _WIN32_WINNT_WIN8

namespace {

typedef void(WINAPI *GetSystemTimeAsFileTimePtr)(LPFILETIME);

class GetSystemTimeInit {
public:
  GetSystemTimeInit() {
    fp = (GetSystemTimeAsFileTimePtr)GetProcAddress(
        GetModuleHandleW(L"kernel32.dll"), "GetSystemTimePreciseAsFileTime");
    if (fp == nullptr)
      fp = GetSystemTimeAsFileTime;
  }
  GetSystemTimeAsFileTimePtr fp;
};

// Pretend we're inside a system header so the compiler doesn't flag the use of the init_priority
// attribute with a value that's reserved for the implementation (we're the implementation).
#include "chrono_system_time_init.h"
} // namespace

#endif

static system_clock::time_point __libcpp_system_clock_now() {
  // FILETIME is in 100ns units
  using filetime_duration =
      _VSTD::chrono::duration<__int64,
                              _VSTD::ratio_multiply<_VSTD::ratio<100, 1>,
                                                    nanoseconds::period>>;

  // The Windows epoch is Jan 1 1601, the Unix epoch Jan 1 1970.
  static _LIBCPP_CONSTEXPR const seconds nt_to_unix_epoch{11644473600};

  FILETIME ft;
#if (_WIN32_WINNT >= _WIN32_WINNT_WIN8 && WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)) || \
    (_WIN32_WINNT >= _WIN32_WINNT_WIN10)
  GetSystemTimePreciseAsFileTime(&ft);
#elif !WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
  GetSystemTimeAsFileTime(&ft);
#else
  GetSystemTimeAsFileTimeFunc.fp(&ft);
#endif

  filetime_duration d{(static_cast<__int64>(ft.dwHighDateTime) << 32) |
                       static_cast<__int64>(ft.dwLowDateTime)};
  return system_clock::time_point(duration_cast<system_clock::duration>(d - nt_to_unix_epoch));
}

#elif defined(CLOCK_REALTIME) && defined(_LIBCPP_USE_CLOCK_GETTIME)

static system_clock::time_point __libcpp_system_clock_now() {
  struct timespec tp;
  if (0 != clock_gettime(CLOCK_REALTIME, &tp))
    __throw_system_error(errno, "clock_gettime(CLOCK_REALTIME) failed");
  return system_clock::time_point(seconds(tp.tv_sec) + microseconds(tp.tv_nsec / 1000));
}

#else

static system_clock::time_point __libcpp_system_clock_now() {
    timeval tv;
    gettimeofday(&tv, 0);
    return system_clock::time_point(seconds(tv.tv_sec) + microseconds(tv.tv_usec));
}

#endif

const bool system_clock::is_steady;

system_clock::time_point
system_clock::now() noexcept
{
    return __libcpp_system_clock_now();
}

time_t
system_clock::to_time_t(const time_point& t) noexcept
{
    return time_t(duration_cast<seconds>(t.time_since_epoch()).count());
}

system_clock::time_point
system_clock::from_time_t(time_t t) noexcept
{
    return system_clock::time_point(seconds(t));
}

//
// steady_clock
//
// Warning:  If this is not truly steady, then it is non-conforming.  It is
//  better for it to not exist and have the rest of libc++ use system_clock
//  instead.
//

#ifndef _LIBCPP_HAS_NO_MONOTONIC_CLOCK

#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
// also counts cycles when the system is asleep. Thus, it is the only
// acceptable implementation of steady_clock.
static steady_clock::time_point __libcpp_steady_clock_now() {
    struct timespec tp;
    if (0 != clock_gettime(CLOCK_MONOTONIC_RAW, &tp))
        __throw_system_error(errno, "clock_gettime(CLOCK_MONOTONIC_RAW) failed");
    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:
//    If the function fails, the return value is zero. <snip>
//    On systems that run Windows XP or later, the function will always succeed
//      and will thus never return zero.

static LARGE_INTEGER
__QueryPerformanceFrequency()
{
    LARGE_INTEGER val;
    (void) QueryPerformanceFrequency(&val);
    return val;
}

static steady_clock::time_point __libcpp_steady_clock_now() {
  static const LARGE_INTEGER freq = __QueryPerformanceFrequency();

  LARGE_INTEGER counter;
  (void) QueryPerformanceCounter(&counter);
  auto seconds = counter.QuadPart / freq.QuadPart;
  auto fractions = counter.QuadPart % freq.QuadPart;
  auto dur = seconds * nano::den + fractions * nano::den / freq.QuadPart;
  return steady_clock::time_point(steady_clock::duration(dur));
}

#elif defined(__MVS__)

static steady_clock::time_point __libcpp_steady_clock_now() {
  struct timespec64 ts;
  if (0 != gettimeofdayMonotonic(&ts))
    __throw_system_error(errno, "failed to obtain time of day");

  return steady_clock::time_point(seconds(ts.tv_sec) + nanoseconds(ts.tv_nsec));
}

#  elif defined(__Fuchsia__)

static steady_clock::time_point __libcpp_steady_clock_now() noexcept {
  // Implicitly link against the vDSO system call ABI without
  // requiring the final link to specify -lzircon explicitly when
  // statically linking libc++.
#    pragma comment(lib, "zircon")

  return steady_clock::time_point(nanoseconds(_zx_clock_get_monotonic()));
}

#  elif defined(CLOCK_MONOTONIC)

static steady_clock::time_point __libcpp_steady_clock_now() {
    struct timespec tp;
    if (0 != clock_gettime(CLOCK_MONOTONIC, &tp))
        __throw_system_error(errno, "clock_gettime(CLOCK_MONOTONIC) failed");
    return steady_clock::time_point(seconds(tp.tv_sec) + nanoseconds(tp.tv_nsec));
}

#  else
#    error "Monotonic clock not implemented on this platform"
#  endif

const bool steady_clock::is_steady;

steady_clock::time_point
steady_clock::now() noexcept
{
    return __libcpp_steady_clock_now();
}

#endif // !_LIBCPP_HAS_NO_MONOTONIC_CLOCK

}

_LIBCPP_END_NAMESPACE_STD