libgfortran/intrinsics/system_clock.c

   1 /* Implementation of the SYSTEM_CLOCK intrinsic.
   2    Copyright (C) 2004-2015 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
  50    Some targets don't support weak undefined references; on these
  51    GTHREAD_USE_WEAK is 0. So we need to define it to 1 on other
  52    targets.  */
  53 #ifndef GTHREAD_USE_WEAK
  54 #define GTHREAD_USE_WEAK 1
  55 #endif
  56
  57 #if SUPPORTS_WEAK && GTHREAD_USE_WEAK && defined(HAVE_CLOCK_GETTIME_LIBRT)
  58 static int weak_gettime (clockid_t, struct timespec *)
  59   __attribute__((__weakref__("clock_gettime")));
  60 #endif
  61
  62
  63 /* High resolution monotonic clock, falling back to the realtime clock
  64    if the target does not support such a clock.
  65
  66    Arguments:
  67    secs     - OUTPUT, seconds
  68    fracsecs - OUTPUT, fractional seconds, units given by tk argument
  69    tk       - OUTPUT, clock resolution [counts/sec]
  70
  71    If the target supports a monotonic clock, the OUTPUT arguments
  72    represent a monotonically incrementing clock starting from some
  73    unspecified time in the past.
  74
  75    If a monotonic clock is not available, falls back to the realtime
  76    clock which is not monotonic.
  77
  78    Return value: 0 for success, -1 for error. In case of error, errno
  79    is set.
  80 */
  81 static int
  82 gf_gettime_mono (time_t * secs, long * fracsecs, long * tck)
  83 {
  84   int err;
  85 #ifdef HAVE_CLOCK_GETTIME
  86   struct timespec ts;
  87   *tck = 1000000000;
  88   err = clock_gettime (GF_CLOCK_MONOTONIC, &ts);
  89   *secs = ts.tv_sec;
  90   *fracsecs = ts.tv_nsec;
  91   return err;
  92 #else
  93 #if defined(HAVE_CLOCK_GETTIME_LIBRT) && SUPPORTS_WEAK && GTHREAD_USE_WEAK
  94   if (weak_gettime)
  95     {
  96       struct timespec ts;
  97       *tck = 1000000000;
  98       err = weak_gettime (GF_CLOCK_MONOTONIC, &ts);
  99       *secs = ts.tv_sec;
 100       *fracsecs = ts.tv_nsec;
 101       return err;
 102     }
 103 #endif
 104   *tck = 1000000;
 105   err = gf_gettime (secs, fracsecs);
 106   return err;
 107 #endif
 108 }
 109
 110 #endif /* !__MINGW32 && !__CYGWIN__  */
 111
 112 extern void
 113 system_clock_4 (GFC_INTEGER_4 *count, GFC_INTEGER_4 *count_rate,
 114                 GFC_INTEGER_4 *count_max);
 115 export_proto(system_clock_4);
 116
 117 extern void
 118 system_clock_8 (GFC_INTEGER_8 *count, GFC_INTEGER_8 *count_rate,
 119                 GFC_INTEGER_8 *count_max);
 120 export_proto(system_clock_8);
 121
 122
 123 /* prefix(system_clock_4) is the INTEGER(4) version of the SYSTEM_CLOCK
 124    intrinsic subroutine.  It returns the number of clock ticks for the current
 125    system time, the number of ticks per second, and the maximum possible value
 126    for COUNT.  */
 127
 128 void
 129 system_clock_4 (GFC_INTEGER_4 *count, GFC_INTEGER_4 *count_rate,
 130                GFC_INTEGER_4 *count_max)
 131 {
 132 #if defined(__MINGW32__) || defined(__CYGWIN__)
 133   if (count)
 134     {
 135       /* Use GetTickCount here as the resolution and range is
 136          sufficient for the INTEGER(kind=4) version, and
 137          QueryPerformanceCounter has potential issues.  */
 138       uint32_t cnt = GetTickCount ();
 139       if (cnt > GFC_INTEGER_4_HUGE)
 140         cnt = cnt - GFC_INTEGER_4_HUGE - 1;
 141       *count = cnt;
 142     }
 143   if (count_rate)
 144     *count_rate = 1000;
 145   if (count_max)
 146     *count_max = GFC_INTEGER_4_HUGE;
 147 #else
 148   time_t secs;
 149   long fracsecs, tck;
 150
 151   if (gf_gettime_mono (&secs, &fracsecs, &tck) == 0)
 152     {
 153       long tck_out = tck > 1000 ? 1000 : tck;
 154       long tck_r = tck / tck_out;
 155       GFC_UINTEGER_4 ucnt = (GFC_UINTEGER_4) secs * tck_out;
 156       ucnt += fracsecs / tck_r;
 157       if (ucnt > GFC_INTEGER_4_HUGE)
 158         ucnt = ucnt - GFC_INTEGER_4_HUGE - 1;
 159       if (count)
 160         *count = ucnt;
 161       if (count_rate)
 162         *count_rate = tck_out;
 163       if (count_max)
 164         *count_max = GFC_INTEGER_4_HUGE;
 165     }
 166   else
 167     {
 168       if (count)
 169         *count = - GFC_INTEGER_4_HUGE;
 170       if (count_rate)
 171         *count_rate = 0;
 172       if (count_max)
 173         *count_max = 0;
 174     }
 175 #endif
 176 }
 177
 178
 179 /* INTEGER(8) version of the above routine.  */
 180
 181 void
 182 system_clock_8 (GFC_INTEGER_8 *count, GFC_INTEGER_8 *count_rate,
 183                  GFC_INTEGER_8 *count_max)
 184 {
 185 #if defined(__MINGW32__) || defined(__CYGWIN__)
 186   LARGE_INTEGER cnt;
 187   LARGE_INTEGER freq;
 188   bool fail = false;
 189   if (count && !QueryPerformanceCounter (&cnt))
 190     fail = true;
 191   if (count_rate && !QueryPerformanceFrequency (&freq))
 192     fail = true;
 193   if (fail)
 194     {
 195       if (count)
 196         *count = - GFC_INTEGER_8_HUGE;
 197       if (count_rate)
 198         *count_rate = 0;
 199       if (count_max)
 200         *count_max = 0;
 201     }
 202   else
 203     {
 204       if (count)
 205         *count = cnt.QuadPart;
 206       if (count_rate)
 207         *count_rate = freq.QuadPart;
 208       if (count_max)
 209         *count_max = GFC_INTEGER_8_HUGE;
 210     }
 211 #else
 212   time_t secs;
 213   long fracsecs, tck;
 214
 215   if (gf_gettime_mono (&secs, &fracsecs, &tck) == 0)
 216     {
 217       GFC_UINTEGER_8 ucnt = (GFC_UINTEGER_8) secs * tck;
 218       ucnt += fracsecs;
 219       if (ucnt > GFC_INTEGER_8_HUGE)
 220         ucnt = ucnt - GFC_INTEGER_8_HUGE - 1;
 221       if (count)
 222         *count = ucnt;
 223       if (count_rate)
 224         *count_rate = tck;
 225       if (count_max)
 226         *count_max = GFC_INTEGER_8_HUGE;
 227     }
 228   else
 229     {
 230       if (count)
 231         *count = - GFC_INTEGER_8_HUGE;
 232       if (count_rate)
 233         *count_rate = 0;
 234       if (count_max)
 235         *count_max = 0;
 236     }
 237 #endif
 238 }