[$(subdir)=misc] (sysdep_headers):
[glibc/history.git] / gmon / mcount.c
blob66da3d054b01c62ff92dbeeb512bf716b8814231
1 /*-
2 * Copyright (c) 1983, 1992, 1993
3 * The Regents of the University of California. All rights reserved.
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 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
34 #if !defined(lint) && !defined(KERNEL) && defined(LIBC_SCCS)
35 static char sccsid[] = "@(#)mcount.c 8.1 (Berkeley) 6/4/93";
36 #endif
38 #include <sys/param.h>
39 #include <sys/gmon.h>
41 /* This file provides the machine-dependent definitions of the _MCOUNT_DECL
42 and MCOUNT macros. */
43 #include "machine-gmon.h"
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>.
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.
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.
60 _MCOUNT_DECL(frompc, selfpc) /* _mcount; may be static, inline, etc */
62 register u_short *frompcindex;
63 register struct tostruct *top, *prevtop;
64 register struct gmonparam *p;
65 register long toindex;
66 #ifdef KERNEL
67 register int s;
68 #endif
69 int i;
71 p = &_gmonparam;
73 * check that we are profiling
74 * and that we aren't recursively invoked.
76 if (p->state != GMON_PROF_ON)
77 return;
78 #ifdef KERNEL
79 MCOUNT_ENTER;
80 #else
81 p->state = GMON_PROF_BUSY;
82 #endif
84 * check that frompcindex is a reasonable pc value.
85 * for example: signal catchers get called from the stack,
86 * not from text space. too bad.
88 frompc -= p->lowpc;
89 if (frompc > p->textsize)
90 goto done;
92 /* avoid integer divide if possible: */
93 if (p->log_hashfraction >= 0) {
94 i = frompc >> p->log_hashfraction;
95 } else {
96 i = frompc / (p->hashfraction * sizeof(*p->froms));
98 frompcindex = &p->froms[i];
99 toindex = *frompcindex;
100 if (toindex == 0) {
102 * first time traversing this arc
104 toindex = ++p->tos[0].link;
105 if (toindex >= p->tolimit)
106 /* halt further profiling */
107 goto overflow;
109 *frompcindex = toindex;
110 top = &p->tos[toindex];
111 top->selfpc = selfpc;
112 top->count = 1;
113 top->link = 0;
114 goto done;
116 top = &p->tos[toindex];
117 if (top->selfpc == selfpc) {
119 * arc at front of chain; usual case.
121 top->count++;
122 goto done;
125 * have to go looking down chain for it.
126 * top points to what we are looking at,
127 * prevtop points to previous top.
128 * we know it is not at the head of the chain.
130 for (; /* goto done */; ) {
131 if (top->link == 0) {
133 * top is end of the chain and none of the chain
134 * had top->selfpc == selfpc.
135 * so we allocate a new tostruct
136 * and link it to the head of the chain.
138 toindex = ++p->tos[0].link;
139 if (toindex >= p->tolimit)
140 goto overflow;
142 top = &p->tos[toindex];
143 top->selfpc = selfpc;
144 top->count = 1;
145 top->link = *frompcindex;
146 *frompcindex = toindex;
147 goto done;
150 * otherwise, check the next arc on the chain.
152 prevtop = top;
153 top = &p->tos[top->link];
154 if (top->selfpc == selfpc) {
156 * there it is.
157 * increment its count
158 * move it to the head of the chain.
160 top->count++;
161 toindex = prevtop->link;
162 prevtop->link = top->link;
163 top->link = *frompcindex;
164 *frompcindex = toindex;
165 goto done;
169 done:
170 #ifdef KERNEL
171 MCOUNT_EXIT;
172 #else
173 p->state = GMON_PROF_ON;
174 #endif
175 return;
176 overflow:
177 p->state = GMON_PROF_ERROR;
178 #ifdef KERNEL
179 MCOUNT_EXIT;
180 #endif
181 return;
185 * Actual definition of mcount function. Defined in <machine/profile.h>,
186 * which is included by <sys/gmon.h>.
188 MCOUNT