1 /* Low-level statistical profiling support function. Mostly POSIX.1 version.
2 Copyright (C) 1996-2015 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
19 #include <sys/types.h>
24 #include <libc-internal.h>
28 #include <gmon/profil.c>
32 static u_short
*samples
;
33 static size_t nsamples
;
34 static size_t pc_offset
;
35 static u_int pc_scale
;
38 profil_count (void *pc
)
40 size_t i
= (pc
- pc_offset
- (void *) 0) / 2;
42 if (sizeof (unsigned long long int) > sizeof (size_t))
43 i
= (unsigned long long int) i
* pc_scale
/ 65536;
45 i
= i
/ 65536 * pc_scale
+ i
% 65536 * pc_scale
/ 65536;
51 /* Get the machine-dependent definition of `__profil_counter', the signal
52 handler for SIGPROF. It calls `profil_count' (above) with the PC of the
54 #include "profil-counter.h"
56 /* Enable statistical profiling, writing samples of the PC into at most
57 SIZE bytes of SAMPLE_BUFFER; every processor clock tick while profiling
58 is enabled, the system examines the user PC and increments
59 SAMPLE_BUFFER[((PC - OFFSET) / 2) * SCALE / 65536]. If SCALE is zero,
60 disable profiling. Returns zero on success, -1 on error. */
63 __profil (u_short
*sample_buffer
, size_t size
, size_t offset
, u_int scale
)
66 struct itimerval timer
;
68 static struct sigaction oact
;
69 static struct itimerval otimer
;
70 # define oact_ptr &oact
71 # define otimer_ptr &otimer
73 if (sample_buffer
== NULL
)
75 /* Disable profiling. */
77 /* Wasn't turned on. */
80 if (__setitimer (ITIMER_PROF
, &otimer
, NULL
) < 0)
83 return __sigaction (SIGPROF
, &oact
, NULL
);
88 /* Was already turned on. Restore old timer and signal handler
90 if (__setitimer (ITIMER_PROF
, &otimer
, NULL
) < 0
91 || __sigaction (SIGPROF
, &oact
, NULL
) < 0)
95 /* In ld.so profiling should never be disabled once it runs. */
96 //assert (sample_buffer != NULL);
97 # define oact_ptr NULL
98 # define otimer_ptr NULL
101 samples
= sample_buffer
;
102 nsamples
= size
/ sizeof *samples
;
106 act
.sa_handler
= (sighandler_t
) &__profil_counter
;
107 act
.sa_flags
= SA_RESTART
;
108 __sigfillset (&act
.sa_mask
);
109 if (__sigaction (SIGPROF
, &act
, oact_ptr
) < 0)
112 timer
.it_value
.tv_sec
= 0;
113 timer
.it_value
.tv_usec
= 1000000 / __profile_frequency ();
114 timer
.it_interval
= timer
.it_value
;
115 return __setitimer (ITIMER_PROF
, &timer
, otimer_ptr
);
117 weak_alias (__profil
, profil
)