128 lines
3.5 KiB
C
128 lines
3.5 KiB
C
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/* Low-level statistical profiling support function. Mostly POSIX.1 version.
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Copyright (C) 1996-2022 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <sys/types.h>
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#include <unistd.h>
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#include <errno.h>
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#include <signal.h>
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#include <sys/time.h>
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#include <stdint.h>
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#include <libc-internal.h>
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#include <sigsetops.h>
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#ifndef SIGPROF
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#include <gmon/profil.c>
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#else
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static u_short *samples;
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static size_t nsamples;
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static size_t pc_offset;
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static u_int pc_scale;
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static inline void
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profil_count (uintptr_t pc)
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{
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size_t i = (pc - pc_offset) / 2;
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if (sizeof (unsigned long long int) > sizeof (size_t))
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i = (unsigned long long int) i * pc_scale / 65536;
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else
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i = i / 65536 * pc_scale + i % 65536 * pc_scale / 65536;
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if (i < nsamples)
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++samples[i];
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}
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/* Get the machine-dependent definition of `__profil_counter', the signal
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handler for SIGPROF. It calls `profil_count' (above) with the PC of the
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interrupted code. */
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#include "profil-counter.h"
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/* Enable statistical profiling, writing samples of the PC into at most
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SIZE bytes of SAMPLE_BUFFER; every processor clock tick while profiling
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is enabled, the system examines the user PC and increments
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SAMPLE_BUFFER[((PC - OFFSET) / 2) * SCALE / 65536]. If SCALE is zero,
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disable profiling. Returns zero on success, -1 on error. */
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int
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__profil (u_short *sample_buffer, size_t size, size_t offset, u_int scale)
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{
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struct sigaction act;
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struct itimerval timer;
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#if !IS_IN (rtld)
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static struct sigaction oact;
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static struct itimerval otimer;
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# define oact_ptr &oact
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# define otimer_ptr &otimer
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if (sample_buffer == NULL)
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{
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/* Disable profiling. */
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if (samples == NULL)
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/* Wasn't turned on. */
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return 0;
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if (__setitimer (ITIMER_PROF, &otimer, NULL) < 0)
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return -1;
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samples = NULL;
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return __sigaction (SIGPROF, &oact, NULL);
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}
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if (samples)
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{
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/* Was already turned on. Restore old timer and signal handler
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first. */
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if (__setitimer (ITIMER_PROF, &otimer, NULL) < 0
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|| __sigaction (SIGPROF, &oact, NULL) < 0)
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return -1;
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}
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#else
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/* In ld.so profiling should never be disabled once it runs. */
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//assert (sample_buffer != NULL);
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# define oact_ptr NULL
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# define otimer_ptr NULL
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#endif
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samples = sample_buffer;
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nsamples = size / sizeof *samples;
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pc_offset = offset;
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pc_scale = scale;
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#ifdef SA_SIGINFO
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act.sa_sigaction = __profil_counter;
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act.sa_flags = SA_SIGINFO;
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#else
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act.sa_handler = __profil_counter;
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act.sa_flags = 0;
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#endif
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act.sa_flags |= SA_RESTART;
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__sigfillset (&act.sa_mask);
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if (__sigaction (SIGPROF, &act, oact_ptr) < 0)
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return -1;
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timer.it_value.tv_sec = 0;
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timer.it_value.tv_usec = 1000000 / __profile_frequency ();
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timer.it_interval = timer.it_value;
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return __setitimer (ITIMER_PROF, &timer, otimer_ptr);
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}
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weak_alias (__profil, profil)
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#endif
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