1 /*-
2 * Copyright (c) 1983, 1992, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 4. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30 #if !defined(lint) && !defined(_KERNEL) && defined(LIBC_SCCS)
31 static char rcsid[] = "$OpenBSD: mcount.c,v 1.6 1997/07/23 21:11:27 kstailey Exp $";
32 #endif
33
34 /*
35 * This file is taken from Cygwin distribution. Please keep it in sync.
36 * The differences should be within __MINGW32__ guard.
37 */
38
39 #ifndef __MINGW32__
40 #include <sys/param.h>
41 #endif
42 #include <sys/types.h>
43 #include "gmon.h"
44
45 /*
46 * mcount is called on entry to each function compiled with the profiling
47 * switch set. _mcount(), which is declared in a machine-dependent way
48 * with _MCOUNT_DECL, does the actual work and is either inlined into a
49 * C routine or called by an assembly stub. In any case, this magic is
50 * taken care of by the MCOUNT definition in <machine/profile.h>.
51 *
52 * _mcount updates data structures that represent traversals of the
53 * program's call graph edges. frompc and selfpc are the return
54 * address and function address that represents the given call graph edge.
55 *
56 * Note: the original BSD code used the same variable (frompcindex) for
57 * both frompcindex and frompc. Any reasonable, modern compiler will
58 * perform this optimization.
59 */
60 /* _mcount; may be static, inline, etc */
61 _MCOUNT_DECL (size_t, size_t);
62
_MCOUNT_DECL(size_t frompc,size_t selfpc)63 _MCOUNT_DECL (size_t frompc, size_t selfpc)
64 {
65 register u_short *frompcindex;
66 register struct tostruct *top, *prevtop;
67 register struct gmonparam *p;
68 register long toindex;
69
70 p = &_gmonparam;
71 /*
72 * check that we are profiling
73 * and that we aren't recursively invoked.
74 */
75 if (p->state != GMON_PROF_ON)
76 return;
77 p->state = GMON_PROF_BUSY;
78 /*
79 * check that frompcindex is a reasonable pc value.
80 * for example: signal catchers get called from the stack,
81 * not from text space. too bad.
82 */
83 frompc -= p->lowpc;
84 if (frompc > p->textsize)
85 goto done;
86
87 #if (HASHFRACTION & (HASHFRACTION - 1)) == 0
88 if (p->hashfraction == HASHFRACTION)
89 frompcindex =
90 &p->froms[frompc / (HASHFRACTION * sizeof(*p->froms))];
91 else
92 #endif
93 frompcindex =
94 &p->froms[frompc / (p->hashfraction * sizeof(*p->froms))];
95 toindex = *frompcindex;
96 if (toindex == 0) {
97 /*
98 * first time traversing this arc
99 */
100 toindex = ++p->tos[0].link;
101 if (toindex >= p->tolimit)
102 /* halt further profiling */
103 goto overflow;
104
105 *frompcindex = toindex;
106 top = &p->tos[toindex];
107 top->selfpc = selfpc;
108 top->count = 1;
109 top->link = 0;
110 goto done;
111 }
112 top = &p->tos[toindex];
113 if (top->selfpc == selfpc) {
114 /*
115 * arc at front of chain; usual case.
116 */
117 top->count++;
118 goto done;
119 }
120 /*
121 * have to go looking down chain for it.
122 * top points to what we are looking at,
123 * prevtop points to previous top.
124 * we know it is not at the head of the chain.
125 */
126 for (; /* goto done */; ) {
127 if (top->link == 0) {
128 /*
129 * top is end of the chain and none of the chain
130 * had top->selfpc == selfpc.
131 * so we allocate a new tostruct
132 * and link it to the head of the chain.
133 */
134 toindex = ++p->tos[0].link;
135 if (toindex >= p->tolimit)
136 goto overflow;
137
138 top = &p->tos[toindex];
139 top->selfpc = selfpc;
140 top->count = 1;
141 top->link = *frompcindex;
142 *frompcindex = toindex;
143 goto done;
144 }
145 /*
146 * otherwise, check the next arc on the chain.
147 */
148 prevtop = top;
149 top = &p->tos[top->link];
150 if (top->selfpc == selfpc) {
151 /*
152 * there it is.
153 * increment its count
154 * move it to the head of the chain.
155 */
156 top->count++;
157 toindex = prevtop->link;
158 prevtop->link = top->link;
159 top->link = *frompcindex;
160 *frompcindex = toindex;
161 goto done;
162 }
163 }
164 done:
165 p->state = GMON_PROF_ON;
166 return;
167 overflow:
168 p->state = GMON_PROF_ERROR;
169 return;
170 }
171
172 /*
173 * Actual definition of mcount function. Defined in <machine/profile.h>,
174 * which is included by <sys/gmon.h>
175 */
176 MCOUNT
177
178