gcc/libgfortran/intrinsics/system_clock.c
2021-01-04 10:26:59 +01:00

231 lines
6.1 KiB
C

/* Implementation of the SYSTEM_CLOCK intrinsic.
Copyright (C) 2004-2021 Free Software Foundation, Inc.
This file is part of the GNU Fortran runtime library (libgfortran).
Libgfortran is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public
License as published by the Free Software Foundation; either
version 3 of the License, or (at your option) any later version.
Libgfortran is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.
You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
<http://www.gnu.org/licenses/>. */
#include "libgfortran.h"
#include <limits.h>
#include "time_1.h"
#if !defined(__MINGW32__)
/* POSIX states that CLOCK_REALTIME must be present if clock_gettime
is available, others are optional. */
#if defined(HAVE_CLOCK_GETTIME) || defined(HAVE_CLOCK_GETTIME_LIBRT)
#if defined(CLOCK_MONOTONIC) && defined(_POSIX_MONOTONIC_CLOCK) \
&& _POSIX_MONOTONIC_CLOCK >= 0
#define GF_CLOCK_MONOTONIC CLOCK_MONOTONIC
#else
#define GF_CLOCK_MONOTONIC CLOCK_REALTIME
#endif
#endif
/* Weakref trickery for clock_gettime(). On Glibc <= 2.16,
clock_gettime() requires us to link in librt, which also pulls in
libpthread. In order to avoid this by default, only call
clock_gettime() through a weak reference. */
#if SUPPORTS_WEAKREF && defined(HAVE_CLOCK_GETTIME_LIBRT)
static int weak_gettime (clockid_t, struct timespec *)
__attribute__((__weakref__("clock_gettime")));
#endif
/* High resolution monotonic clock, falling back to the realtime clock
if the target does not support such a clock.
Arguments:
secs - OUTPUT, seconds
fracsecs - OUTPUT, fractional seconds, units given by tk argument
tk - OUTPUT, clock resolution [counts/sec]
If the target supports a monotonic clock, the OUTPUT arguments
represent a monotonically incrementing clock starting from some
unspecified time in the past.
If a monotonic clock is not available, falls back to the realtime
clock which is not monotonic.
Return value: 0 for success, -1 for error. In case of error, errno
is set.
*/
static int
gf_gettime_mono (time_t * secs, long * fracsecs, long * tck)
{
int err;
#ifdef HAVE_CLOCK_GETTIME
struct timespec ts;
*tck = 1000000000;
err = clock_gettime (GF_CLOCK_MONOTONIC, &ts);
*secs = ts.tv_sec;
*fracsecs = ts.tv_nsec;
return err;
#else
#if SUPPORTS_WEAKREF && defined(HAVE_CLOCK_GETTIME_LIBRT)
if (weak_gettime)
{
struct timespec ts;
*tck = 1000000000;
err = weak_gettime (GF_CLOCK_MONOTONIC, &ts);
*secs = ts.tv_sec;
*fracsecs = ts.tv_nsec;
return err;
}
#endif
*tck = 1000000;
err = gf_gettime (secs, fracsecs);
return err;
#endif
}
#endif /* !__MINGW32__ */
extern void
system_clock_4 (GFC_INTEGER_4 *count, GFC_INTEGER_4 *count_rate,
GFC_INTEGER_4 *count_max);
export_proto(system_clock_4);
extern void
system_clock_8 (GFC_INTEGER_8 *count, GFC_INTEGER_8 *count_rate,
GFC_INTEGER_8 *count_max);
export_proto(system_clock_8);
/* prefix(system_clock_4) is the INTEGER(4) version of the SYSTEM_CLOCK
intrinsic subroutine. It returns the number of clock ticks for the current
system time, the number of ticks per second, and the maximum possible value
for COUNT. */
void
system_clock_4 (GFC_INTEGER_4 *count, GFC_INTEGER_4 *count_rate,
GFC_INTEGER_4 *count_max)
{
#if defined(__MINGW32__)
if (count)
{
/* Use GetTickCount here as the resolution and range is
sufficient for the INTEGER(kind=4) version, and
QueryPerformanceCounter has potential issues. */
uint32_t cnt = GetTickCount ();
if (cnt > GFC_INTEGER_4_HUGE)
cnt = cnt - GFC_INTEGER_4_HUGE - 1;
*count = cnt;
}
if (count_rate)
*count_rate = 1000;
if (count_max)
*count_max = GFC_INTEGER_4_HUGE;
#else
time_t secs;
long fracsecs, tck;
if (gf_gettime_mono (&secs, &fracsecs, &tck) == 0)
{
long tck_out = tck > 1000 ? 1000 : tck;
long tck_r = tck / tck_out;
GFC_UINTEGER_4 ucnt = (GFC_UINTEGER_4) secs * tck_out;
ucnt += fracsecs / tck_r;
if (ucnt > GFC_INTEGER_4_HUGE)
ucnt = ucnt - GFC_INTEGER_4_HUGE - 1;
if (count)
*count = ucnt;
if (count_rate)
*count_rate = tck_out;
if (count_max)
*count_max = GFC_INTEGER_4_HUGE;
}
else
{
if (count)
*count = - GFC_INTEGER_4_HUGE;
if (count_rate)
*count_rate = 0;
if (count_max)
*count_max = 0;
}
#endif
}
/* INTEGER(8) version of the above routine. */
void
system_clock_8 (GFC_INTEGER_8 *count, GFC_INTEGER_8 *count_rate,
GFC_INTEGER_8 *count_max)
{
#if defined(__MINGW32__)
LARGE_INTEGER cnt;
LARGE_INTEGER freq;
bool fail = false;
if (count && !QueryPerformanceCounter (&cnt))
fail = true;
if (count_rate && !QueryPerformanceFrequency (&freq))
fail = true;
if (fail)
{
if (count)
*count = - GFC_INTEGER_8_HUGE;
if (count_rate)
*count_rate = 0;
if (count_max)
*count_max = 0;
}
else
{
if (count)
*count = cnt.QuadPart;
if (count_rate)
*count_rate = freq.QuadPart;
if (count_max)
*count_max = GFC_INTEGER_8_HUGE;
}
#else
time_t secs;
long fracsecs, tck;
if (gf_gettime_mono (&secs, &fracsecs, &tck) == 0)
{
GFC_UINTEGER_8 ucnt = (GFC_UINTEGER_8) secs * tck;
ucnt += fracsecs;
if (ucnt > GFC_INTEGER_8_HUGE)
ucnt = ucnt - GFC_INTEGER_8_HUGE - 1;
if (count)
*count = ucnt;
if (count_rate)
*count_rate = tck;
if (count_max)
*count_max = GFC_INTEGER_8_HUGE;
}
else
{
if (count)
*count = - GFC_INTEGER_8_HUGE;
if (count_rate)
*count_rate = 0;
if (count_max)
*count_max = 0;
}
#endif
}