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dc2dea03 KM |
1 | /*- |
2 | * Copyright (c) 1983, 1992 The Regents of the University of California. | |
3 | * All rights reserved. | |
4 | * | |
5 | * %sccs.include.redist.c% | |
6 | */ | |
7 | ||
8 | #if !defined(lint) && !defined(KERNEL) && defined(LIBC_SCCS) | |
7e3de512 | 9 | static char sccsid[] = "@(#)mcount.c 5.2 (Berkeley) %G%"; |
dc2dea03 KM |
10 | #endif |
11 | ||
12 | #include <sys/param.h> | |
13 | #include <sys/gmon.h> | |
14 | ||
15 | /* | |
16 | * mcount is called on entry to each function compiled with the profiling | |
17 | * switch set. _mcount(), which is declared in a machine-dependent way | |
18 | * with _MCOUNT_DECL, does the actual work and is either inlined into a | |
19 | * C routine or called by an assembly stub. In any case, this magic is | |
7e3de512 | 20 | * taken care of by the MCOUNT definition in <machine/profile.h>. |
dc2dea03 KM |
21 | * |
22 | * _mcount updates data structures that represent traversals of the | |
23 | * program's call graph edges. frompc and selfpc are the return | |
24 | * address and function address that represents the given call graph edge. | |
25 | * | |
26 | * Note: the original BSD code used the same variable (frompcindex) for | |
27 | * both frompcindex and frompc. Any reasonable, modern compiler will | |
28 | * perform this optimization. | |
29 | */ | |
30 | _MCOUNT_DECL(frompc, selfpc) /* _mcount; may be static, inline, etc */ | |
31 | register u_long frompc, selfpc; | |
32 | { | |
33 | register u_short *frompcindex; | |
34 | register struct tostruct *top, *prevtop; | |
35 | register struct gmonparam *p; | |
36 | register long toindex; | |
37 | #ifdef KERNEL | |
38 | register int s; | |
39 | #endif | |
40 | ||
41 | p = &_gmonparam; | |
42 | /* | |
43 | * check that we are profiling | |
44 | * and that we aren't recursively invoked. | |
45 | */ | |
46 | if (p->state != GMON_PROF_ON) | |
47 | return; | |
48 | #ifdef KERNEL | |
49 | MCOUNT_ENTER; | |
50 | #else | |
51 | p->state = GMON_PROF_BUSY; | |
52 | #endif | |
53 | /* | |
54 | * check that frompcindex is a reasonable pc value. | |
55 | * for example: signal catchers get called from the stack, | |
56 | * not from text space. too bad. | |
57 | */ | |
58 | frompc -= p->lowpc; | |
59 | if (frompc > p->textsize) | |
60 | goto done; | |
61 | ||
62 | frompcindex = &p->froms[frompc / (HASHFRACTION * sizeof(*p->froms))]; | |
63 | toindex = *frompcindex; | |
64 | if (toindex == 0) { | |
65 | /* | |
66 | * first time traversing this arc | |
67 | */ | |
68 | toindex = ++p->tos[0].link; | |
69 | if (toindex >= p->tolimit) | |
70 | /* halt further profiling */ | |
71 | goto overflow; | |
72 | ||
73 | *frompcindex = toindex; | |
74 | top = &p->tos[toindex]; | |
75 | top->selfpc = selfpc; | |
76 | top->count = 1; | |
77 | top->link = 0; | |
78 | goto done; | |
79 | } | |
80 | top = &p->tos[toindex]; | |
81 | if (top->selfpc == selfpc) { | |
82 | /* | |
83 | * arc at front of chain; usual case. | |
84 | */ | |
85 | top->count++; | |
86 | goto done; | |
87 | } | |
88 | /* | |
89 | * have to go looking down chain for it. | |
90 | * top points to what we are looking at, | |
91 | * prevtop points to previous top. | |
92 | * we know it is not at the head of the chain. | |
93 | */ | |
94 | for (; /* goto done */; ) { | |
95 | if (top->link == 0) { | |
96 | /* | |
97 | * top is end of the chain and none of the chain | |
98 | * had top->selfpc == selfpc. | |
99 | * so we allocate a new tostruct | |
100 | * and link it to the head of the chain. | |
101 | */ | |
102 | toindex = ++p->tos[0].link; | |
103 | if (toindex >= p->tolimit) | |
104 | goto overflow; | |
105 | ||
106 | top = &p->tos[toindex]; | |
107 | top->selfpc = selfpc; | |
108 | top->count = 1; | |
109 | top->link = *frompcindex; | |
110 | *frompcindex = toindex; | |
111 | goto done; | |
112 | } | |
113 | /* | |
114 | * otherwise, check the next arc on the chain. | |
115 | */ | |
116 | prevtop = top; | |
117 | top = &p->tos[top->link]; | |
118 | if (top->selfpc == selfpc) { | |
119 | /* | |
120 | * there it is. | |
121 | * increment its count | |
122 | * move it to the head of the chain. | |
123 | */ | |
124 | top->count++; | |
125 | toindex = prevtop->link; | |
126 | prevtop->link = top->link; | |
127 | top->link = *frompcindex; | |
128 | *frompcindex = toindex; | |
129 | goto done; | |
130 | } | |
131 | ||
132 | } | |
133 | done: | |
134 | #ifdef KERNEL | |
135 | MCOUNT_EXIT; | |
136 | #else | |
137 | p->state = GMON_PROF_ON; | |
138 | #endif | |
139 | return; | |
140 | overflow: | |
141 | p->state = GMON_PROF_ERROR; | |
142 | #ifdef KERNEL | |
143 | MCOUNT_EXIT; | |
144 | #endif | |
145 | return; | |
146 | } | |
147 | ||
148 | /* | |
7e3de512 | 149 | * Actual definition of mcount function. Defined in <machine/profile.h>, |
dc2dea03 KM |
150 | * which is included by <sys/gmon.h>. |
151 | */ | |
152 | MCOUNT |