1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
|
/*-
* Copyright (c) 1983, 1992, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#if !defined(lint) && !defined(KERNEL) && defined(LIBC_SCCS)
static char sccsid[] = "@(#)mcount.c 8.1 (Berkeley) 6/4/93";
#endif
#include <unistd.h>
#include <sys/param.h>
#include <sys/gmon.h>
/* This file provides the machine-dependent definitions of the _MCOUNT_DECL
and MCOUNT macros. */
#include <machine-gmon.h>
#include <atomic.h>
/*
* mcount is called on entry to each function compiled with the profiling
* switch set. _mcount(), which is declared in a machine-dependent way
* with _MCOUNT_DECL, does the actual work and is either inlined into a
* C routine or called by an assembly stub. In any case, this magic is
* taken care of by the MCOUNT definition in <machine/profile.h>.
*
* _mcount updates data structures that represent traversals of the
* program's call graph edges. frompc and selfpc are the return
* address and function address that represents the given call graph edge.
*
* Note: the original BSD code used the same variable (frompcindex) for
* both frompcindex and frompc. Any reasonable, modern compiler will
* perform this optimization.
*/
_MCOUNT_DECL(frompc, selfpc) /* _mcount; may be static, inline, etc */
{
register ARCINDEX *frompcindex;
register struct tostruct *top, *prevtop;
register struct gmonparam *p;
register ARCINDEX toindex;
int i;
p = &_gmonparam;
/*
* check that we are profiling
* and that we aren't recursively invoked.
*/
if (catomic_compare_and_exchange_bool_acq (&p->state, GMON_PROF_BUSY,
GMON_PROF_ON))
return;
/*
* check that frompcindex is a reasonable pc value.
* for example: signal catchers get called from the stack,
* not from text space. too bad.
*/
frompc -= p->lowpc;
if (frompc > p->textsize)
goto done;
/* The following test used to be
if (p->log_hashfraction >= 0)
But we can simplify this if we assume the profiling data
is always initialized by the functions in gmon.c. But
then it is possible to avoid a runtime check and use the
smae `if' as in gmon.c. So keep these tests in sync. */
if ((HASHFRACTION & (HASHFRACTION - 1)) == 0) {
/* avoid integer divide if possible: */
i = frompc >> p->log_hashfraction;
} else {
i = frompc / (p->hashfraction * sizeof(*p->froms));
}
frompcindex = &p->froms[i];
toindex = *frompcindex;
if (toindex == 0) {
/*
* first time traversing this arc
*/
toindex = ++p->tos[0].link;
if (toindex >= p->tolimit)
/* halt further profiling */
goto overflow;
*frompcindex = toindex;
top = &p->tos[toindex];
top->selfpc = selfpc;
top->count = 1;
top->link = 0;
goto done;
}
top = &p->tos[toindex];
if (top->selfpc == selfpc) {
/*
* arc at front of chain; usual case.
*/
top->count++;
goto done;
}
/*
* have to go looking down chain for it.
* top points to what we are looking at,
* prevtop points to previous top.
* we know it is not at the head of the chain.
*/
for (; /* goto done */; ) {
if (top->link == 0) {
/*
* top is end of the chain and none of the chain
* had top->selfpc == selfpc.
* so we allocate a new tostruct
* and link it to the head of the chain.
*/
toindex = ++p->tos[0].link;
if (toindex >= p->tolimit)
goto overflow;
top = &p->tos[toindex];
top->selfpc = selfpc;
top->count = 1;
top->link = *frompcindex;
*frompcindex = toindex;
goto done;
}
/*
* otherwise, check the next arc on the chain.
*/
prevtop = top;
top = &p->tos[top->link];
if (top->selfpc == selfpc) {
/*
* there it is.
* increment its count
* move it to the head of the chain.
*/
top->count++;
toindex = prevtop->link;
prevtop->link = top->link;
top->link = *frompcindex;
*frompcindex = toindex;
goto done;
}
}
done:
p->state = GMON_PROF_ON;
return;
overflow:
p->state = GMON_PROF_ERROR;
return;
}
/*
* Actual definition of mcount function. Defined in <machine/profile.h>,
* which is included by <sys/gmon.h>.
*/
MCOUNT
|
