libgfortran/intrinsics/system_clock.c

   1 /* Implementation of the SYSTEM_CLOCK intrinsic.
   2    Copyright (C) 2004-2017 Free Software Foundation, Inc.
   3
   4 This file is part of the GNU Fortran runtime library (libgfortran).
   5
   6 Libgfortran is free software; you can redistribute it and/or
   7 modify it under the terms of the GNU General Public
   8 License as published by the Free Software Foundation; either
   9 version 3 of the License, or (at your option) any later version.
  10
  11 Libgfortran is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 Under Section 7 of GPL version 3, you are granted additional
  17 permissions described in the GCC Runtime Library Exception, version
  18 3.1, as published by the Free Software Foundation.
  19
  20 You should have received a copy of the GNU General Public License and
  21 a copy of the GCC Runtime Library Exception along with this program;
  22 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23 <http://www.gnu.org/licenses/>.  */
  24
  25 #include "libgfortran.h"
  26
  27 #include <limits.h>
  28
  29 #include "time_1.h"
  30
  31
  32 #if !defined(__MINGW32__) && !defined(__CYGWIN__)
  33
  34 /* POSIX states that CLOCK_REALTIME must be present if clock_gettime
  35    is available, others are optional.  */
  36 #if defined(HAVE_CLOCK_GETTIME) || defined(HAVE_CLOCK_GETTIME_LIBRT)
  37 #if defined(CLOCK_MONOTONIC) && defined(_POSIX_MONOTONIC_CLOCK) \
  38   && _POSIX_MONOTONIC_CLOCK >= 0
  39 #define GF_CLOCK_MONOTONIC CLOCK_MONOTONIC
  40 #else
  41 #define GF_CLOCK_MONOTONIC CLOCK_REALTIME
  42 #endif
  43 #endif
  44
  45 /* Weakref trickery for clock_gettime().  On Glibc <= 2.16,
  46    clock_gettime() requires us to link in librt, which also pulls in
  47    libpthread.  In order to avoid this by default, only call
  48    clock_gettime() through a weak reference.  */
  49 #if SUPPORTS_WEAKREF && defined(HAVE_CLOCK_GETTIME_LIBRT)
  50 static int weak_gettime (clockid_t, struct timespec *)
  51   __attribute__((__weakref__("clock_gettime")));
  52 #endif
  53
  54
  55 /* High resolution monotonic clock, falling back to the realtime clock
  56    if the target does not support such a clock.
  57
  58    Arguments:
  59    secs     - OUTPUT, seconds
  60    fracsecs - OUTPUT, fractional seconds, units given by tk argument
  61    tk       - OUTPUT, clock resolution [counts/sec]
  62
  63    If the target supports a monotonic clock, the OUTPUT arguments
  64    represent a monotonically incrementing clock starting from some
  65    unspecified time in the past.
  66
  67    If a monotonic clock is not available, falls back to the realtime
  68    clock which is not monotonic.
  69
  70    Return value: 0 for success, -1 for error. In case of error, errno
  71    is set.
  72 */
  73 static int
  74 gf_gettime_mono (time_t * secs, long * fracsecs, long * tck)
  75 {
  76   int err;
  77 #ifdef HAVE_CLOCK_GETTIME
  78   struct timespec ts;
  79   *tck = 1000000000;
  80   err = clock_gettime (GF_CLOCK_MONOTONIC, &ts);
  81   *secs = ts.tv_sec;
  82   *fracsecs = ts.tv_nsec;
  83   return err;
  84 #else
  85 #if SUPPORTS_WEAKREF && defined(HAVE_CLOCK_GETTIME_LIBRT)
  86   if (weak_gettime)
  87     {
  88       struct timespec ts;
  89       *tck = 1000000000;
  90       err = weak_gettime (GF_CLOCK_MONOTONIC, &ts);
  91       *secs = ts.tv_sec;
  92       *fracsecs = ts.tv_nsec;
  93       return err;
  94     }
  95 #endif
  96   *tck = 1000000;
  97   err = gf_gettime (secs, fracsecs);
  98   return err;
  99 #endif
 100 }
 101
 102 #endif /* !__MINGW32 && !__CYGWIN__  */
 103
 104 extern void
 105 system_clock_4 (GFC_INTEGER_4 *count, GFC_INTEGER_4 *count_rate,
 106                 GFC_INTEGER_4 *count_max);
 107 export_proto(system_clock_4);
 108
 109 extern void
 110 system_clock_8 (GFC_INTEGER_8 *count, GFC_INTEGER_8 *count_rate,
 111                 GFC_INTEGER_8 *count_max);
 112 export_proto(system_clock_8);
 113
 114
 115 /* prefix(system_clock_4) is the INTEGER(4) version of the SYSTEM_CLOCK
 116    intrinsic subroutine.  It returns the number of clock ticks for the current
 117    system time, the number of ticks per second, and the maximum possible value
 118    for COUNT.  */
 119
 120 void
 121 system_clock_4 (GFC_INTEGER_4 *count, GFC_INTEGER_4 *count_rate,
 122                GFC_INTEGER_4 *count_max)
 123 {
 124 #if defined(__MINGW32__) || defined(__CYGWIN__)
 125   if (count)
 126     {
 127       /* Use GetTickCount here as the resolution and range is
 128          sufficient for the INTEGER(kind=4) version, and
 129          QueryPerformanceCounter has potential issues.  */
 130       uint32_t cnt = GetTickCount ();
 131       if (cnt > GFC_INTEGER_4_HUGE)
 132         cnt = cnt - GFC_INTEGER_4_HUGE - 1;
 133       *count = cnt;
 134     }
 135   if (count_rate)
 136     *count_rate = 1000;
 137   if (count_max)
 138     *count_max = GFC_INTEGER_4_HUGE;
 139 #else
 140   time_t secs;
 141   long fracsecs, tck;
 142
 143   if (gf_gettime_mono (&secs, &fracsecs, &tck) == 0)
 144     {
 145       long tck_out = tck > 1000 ? 1000 : tck;
 146       long tck_r = tck / tck_out;
 147       GFC_UINTEGER_4 ucnt = (GFC_UINTEGER_4) secs * tck_out;
 148       ucnt += fracsecs / tck_r;
 149       if (ucnt > GFC_INTEGER_4_HUGE)
 150         ucnt = ucnt - GFC_INTEGER_4_HUGE - 1;
 151       if (count)
 152         *count = ucnt;
 153       if (count_rate)
 154         *count_rate = tck_out;
 155       if (count_max)
 156         *count_max = GFC_INTEGER_4_HUGE;
 157     }
 158   else
 159     {
 160       if (count)
 161         *count = - GFC_INTEGER_4_HUGE;
 162       if (count_rate)
 163         *count_rate = 0;
 164       if (count_max)
 165         *count_max = 0;
 166     }
 167 #endif
 168 }
 169
 170
 171 /* INTEGER(8) version of the above routine.  */
 172
 173 void
 174 system_clock_8 (GFC_INTEGER_8 *count, GFC_INTEGER_8 *count_rate,
 175                  GFC_INTEGER_8 *count_max)
 176 {
 177 #if defined(__MINGW32__) || defined(__CYGWIN__)
 178   LARGE_INTEGER cnt;
 179   LARGE_INTEGER freq;
 180   bool fail = false;
 181   if (count && !QueryPerformanceCounter (&cnt))
 182     fail = true;
 183   if (count_rate && !QueryPerformanceFrequency (&freq))
 184     fail = true;
 185   if (fail)
 186     {
 187       if (count)
 188         *count = - GFC_INTEGER_8_HUGE;
 189       if (count_rate)
 190         *count_rate = 0;
 191       if (count_max)
 192         *count_max = 0;
 193     }
 194   else
 195     {
 196       if (count)
 197         *count = cnt.QuadPart;
 198       if (count_rate)
 199         *count_rate = freq.QuadPart;
 200       if (count_max)
 201         *count_max = GFC_INTEGER_8_HUGE;
 202     }
 203 #else
 204   time_t secs;
 205   long fracsecs, tck;
 206
 207   if (gf_gettime_mono (&secs, &fracsecs, &tck) == 0)
 208     {
 209       GFC_UINTEGER_8 ucnt = (GFC_UINTEGER_8) secs * tck;
 210       ucnt += fracsecs;
 211       if (ucnt > GFC_INTEGER_8_HUGE)
 212         ucnt = ucnt - GFC_INTEGER_8_HUGE - 1;
 213       if (count)
 214         *count = ucnt;
 215       if (count_rate)
 216         *count_rate = tck;
 217       if (count_max)
 218         *count_max = GFC_INTEGER_8_HUGE;
 219     }
 220   else
 221     {
 222       if (count)
 223         *count = - GFC_INTEGER_8_HUGE;
 224       if (count_rate)
 225         *count_rate = 0;
 226       if (count_max)
 227         *count_max = 0;
 228     }
 229 #endif
 230 }