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 * 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. 20 * 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. 32 */ 33 34 #if !defined(lint) && !defined(_KERNEL) && defined(LIBC_SCCS) 35 static char rcsid[] = "$OpenBSD: mcount.c,v 1.5 1997/01/30 05:05:00 deraadt Exp $"; 36 #endif 37 38 #include <sys/param.h> 39 #include <sys/gmon.h> 40 41 /* 42 * mcount is called on entry to each function compiled with the profiling 43 * switch set. _mcount(), which is declared in a machine-dependent way 44 * with _MCOUNT_DECL, does the actual work and is either inlined into a 45 * C routine or called by an assembly stub. In any case, this magic is 46 * taken care of by the MCOUNT definition in <machine/profile.h>. 47 * 48 * _mcount updates data structures that represent traversals of the 49 * program's call graph edges. frompc and selfpc are the return 50 * address and function address that represents the given call graph edge. 51 * 52 * Note: the original BSD code used the same variable (frompcindex) for 53 * both frompcindex and frompc. Any reasonable, modern compiler will 54 * perform this optimization. 55 */ 56 _MCOUNT_DECL __P((u_long frompc, u_long selfpc)); 57 _MCOUNT_DECL(frompc, selfpc) /* _mcount; may be static, inline, etc */ 58 register u_long frompc, selfpc; 59 { 60 register u_short *frompcindex; 61 register struct tostruct *top, *prevtop; 62 register struct gmonparam *p; 63 register long toindex; 64 #ifdef _KERNEL 65 register int s; 66 #endif 67 68 p = &_gmonparam; 69 /* 70 * check that we are profiling 71 * and that we aren't recursively invoked. 72 */ 73 if (p->state != GMON_PROF_ON) 74 return; 75 #ifdef _KERNEL 76 MCOUNT_ENTER; 77 #else 78 p->state = GMON_PROF_BUSY; 79 #endif 80 /* 81 * check that frompcindex is a reasonable pc value. 82 * for example: signal catchers get called from the stack, 83 * not from text space. too bad. 84 */ 85 frompc -= p->lowpc; 86 if (frompc > p->textsize) 87 goto done; 88 89 #if (HASHFRACTION & (HASHFRACTION - 1)) == 0 90 if (p->hashfraction == HASHFRACTION) 91 frompcindex = 92 &p->froms[frompc / (HASHFRACTION * sizeof(*p->froms))]; 93 else 94 #endif 95 frompcindex = 96 &p->froms[frompc / (p->hashfraction * sizeof(*p->froms))]; 97 toindex = *frompcindex; 98 if (toindex == 0) { 99 /* 100 * first time traversing this arc 101 */ 102 toindex = ++p->tos[0].link; 103 if (toindex >= p->tolimit) 104 /* halt further profiling */ 105 goto overflow; 106 107 *frompcindex = toindex; 108 top = &p->tos[toindex]; 109 top->selfpc = selfpc; 110 top->count = 1; 111 top->link = 0; 112 goto done; 113 } 114 top = &p->tos[toindex]; 115 if (top->selfpc == selfpc) { 116 /* 117 * arc at front of chain; usual case. 118 */ 119 top->count++; 120 goto done; 121 } 122 /* 123 * have to go looking down chain for it. 124 * top points to what we are looking at, 125 * prevtop points to previous top. 126 * we know it is not at the head of the chain. 127 */ 128 for (; /* goto done */; ) { 129 if (top->link == 0) { 130 /* 131 * top is end of the chain and none of the chain 132 * had top->selfpc == selfpc. 133 * so we allocate a new tostruct 134 * and link it to the head of the chain. 135 */ 136 toindex = ++p->tos[0].link; 137 if (toindex >= p->tolimit) 138 goto overflow; 139 140 top = &p->tos[toindex]; 141 top->selfpc = selfpc; 142 top->count = 1; 143 top->link = *frompcindex; 144 *frompcindex = toindex; 145 goto done; 146 } 147 /* 148 * otherwise, check the next arc on the chain. 149 */ 150 prevtop = top; 151 top = &p->tos[top->link]; 152 if (top->selfpc == selfpc) { 153 /* 154 * there it is. 155 * increment its count 156 * move it to the head of the chain. 157 */ 158 top->count++; 159 toindex = prevtop->link; 160 prevtop->link = top->link; 161 top->link = *frompcindex; 162 *frompcindex = toindex; 163 goto done; 164 } 165 166 } 167 done: 168 #ifdef _KERNEL 169 MCOUNT_EXIT; 170 #else 171 p->state = GMON_PROF_ON; 172 #endif 173 return; 174 overflow: 175 p->state = GMON_PROF_ERROR; 176 #ifdef _KERNEL 177 MCOUNT_EXIT; 178 #endif 179 return; 180 } 181 182 #ifndef lint 183 /* 184 * Actual definition of mcount function. Defined in <machine/profile.h>, 185 * which is included by <sys/gmon.h>. 186 */ 187 MCOUNT 188 #endif 189