libgfortran/intrinsics/system_clock.c

   1 /* Implementation of the SYSTEM_CLOCK intrinsic.
   2    Copyright (C) 2004-2013 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 system_clock_4 (GFC_INTEGER_4 *, GFC_INTEGER_4 *, GFC_INTEGER_4 *);
 113 export_proto(system_clock_4);
 114
 115 extern void system_clock_8 (GFC_INTEGER_8 *, GFC_INTEGER_8 *, GFC_INTEGER_8 *);
 116 export_proto(system_clock_8);
 117
 118
 119 /* prefix(system_clock_4) is the INTEGER(4) version of the SYSTEM_CLOCK
 120    intrinsic subroutine.  It returns the number of clock ticks for the current
 121    system time, the number of ticks per second, and the maximum possible value
 122    for COUNT.  */
 123
 124 void
 125 system_clock_4(GFC_INTEGER_4 *count, GFC_INTEGER_4 *count_rate,
 126                GFC_INTEGER_4 *count_max)
 127 {
 128 #if defined(__MINGW32__) || defined(__CYGWIN__)
 129   if (count)
 130     {
 131       /* Use GetTickCount here as the resolution and range is
 132          sufficient for the INTEGER(kind=4) version, and
 133          QueryPerformanceCounter has potential issues.  */
 134       uint32_t cnt = GetTickCount ();
 135       if (cnt > GFC_INTEGER_4_HUGE)
 136         cnt = cnt - GFC_INTEGER_4_HUGE - 1;
 137       *count = cnt;
 138     }
 139   if (count_rate)
 140     *count_rate = 1000;
 141   if (count_max)
 142     *count_max = GFC_INTEGER_4_HUGE;
 143 #else
 144   time_t secs;
 145   long fracsecs, tck;
 146
 147   if (gf_gettime_mono (&secs, &fracsecs, &tck) == 0)
 148     {
 149       long tck_out = tck > 1000 ? 1000 : tck;
 150       long tck_r = tck / tck_out;
 151       GFC_UINTEGER_4 ucnt = (GFC_UINTEGER_4) secs * tck_out;
 152       ucnt += fracsecs / tck_r;
 153       if (ucnt > GFC_INTEGER_4_HUGE)
 154         ucnt = ucnt - GFC_INTEGER_4_HUGE - 1;
 155       if (count)
 156         *count = ucnt;
 157       if (count_rate)
 158         *count_rate = tck_out;
 159       if (count_max)
 160         *count_max = GFC_INTEGER_4_HUGE;
 161     }
 162   else
 163     {
 164       if (count)
 165         *count = - GFC_INTEGER_4_HUGE;
 166       if (count_rate)
 167         *count_rate = 0;
 168       if (count_max)
 169         *count_max = 0;
 170     }
 171 #endif
 172 }
 173
 174
 175 /* INTEGER(8) version of the above routine.  */
 176
 177 void
 178 system_clock_8 (GFC_INTEGER_8 *count, GFC_INTEGER_8 *count_rate,
 179                 GFC_INTEGER_8 *count_max)
 180 {
 181 #if defined(__MINGW32__) || defined(__CYGWIN__)
 182   LARGE_INTEGER cnt;
 183   LARGE_INTEGER freq;
 184   bool fail = false;
 185   if (count && !QueryPerformanceCounter (&cnt))
 186     fail = true;
 187   if (count_rate && !QueryPerformanceFrequency (&freq))
 188     fail = true;
 189   if (fail)
 190     {
 191       if (count)
 192         *count = - GFC_INTEGER_8_HUGE;
 193       if (count_rate)
 194         *count_rate = 0;
 195       if (count_max)
 196         *count_max = 0;
 197     }
 198   else
 199     {
 200       if (count)
 201         *count = cnt.QuadPart;
 202       if (count_rate)
 203         *count_rate = freq.QuadPart;
 204       if (count_max)
 205         *count_max = GFC_INTEGER_8_HUGE;
 206     }
 207 #else
 208   time_t secs;
 209   long fracsecs, tck;
 210
 211   if (gf_gettime_mono (&secs, &fracsecs, &tck) == 0)
 212     {
 213       GFC_UINTEGER_8 ucnt = (GFC_UINTEGER_8) secs * tck;
 214       ucnt += fracsecs;
 215       if (ucnt > GFC_INTEGER_8_HUGE)
 216         ucnt = ucnt - GFC_INTEGER_8_HUGE - 1;
 217       if (count)
 218         *count = ucnt;
 219       if (count_rate)
 220         *count_rate = tck;
 221       if (count_max)
 222         *count_max = GFC_INTEGER_8_HUGE;
 223     }
 224   else
 225     {
 226       if (count)
 227         *count = - GFC_INTEGER_8_HUGE;
 228       if (count_rate)
 229         *count_rate = 0;
 230       if (count_max)
 231         *count_max = 0;
 232     }
 233 #endif
 234 }