1 /* $OpenBSD: mcount.c,v 1.4 1997/11/07 15:56:45 niklas Exp $ */ 2 /* $NetBSD: mcount.c,v 1.3.6.1 1996/06/12 04:23:01 cgd Exp $ */ 3 4 /*- 5 * Copyright (c) 1983, 1992, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 #if !defined(lint) && !defined(_KERNEL) && defined(LIBC_SCCS) 38 #if 0 39 static char sccsid[] = "@(#)mcount.c 8.1 (Berkeley) 6/4/93"; 40 #else 41 static char rcsid[] = "$OpenBSD: mcount.c,v 1.4 1997/11/07 15:56:45 niklas Exp $"; 42 #endif 43 #endif 44 45 #include <sys/param.h> 46 #include <sys/gmon.h> 47 48 /* 49 * mcount is called on entry to each function compiled with the profiling 50 * switch set. _mcount(), which is declared in a machine-dependent way 51 * with _MCOUNT_DECL, does the actual work and is either inlined into a 52 * C routine or called by an assembly stub. In any case, this magic is 53 * taken care of by the MCOUNT definition in <machine/profile.h>. 54 * 55 * _mcount updates data structures that represent traversals of the 56 * program's call graph edges. frompc and selfpc are the return 57 * address and function address that represents the given call graph edge. 58 * 59 * Note: the original BSD code used the same variable (frompcindex) for 60 * both frompcindex and frompc. Any reasonable, modern compiler will 61 * perform this optimization. 62 */ 63 _MCOUNT_DECL(u_long frompc, u_long selfpc); 64 _MCOUNT_DECL(frompc, selfpc) /* _mcount; may be static, inline, etc */ 65 register u_long frompc, selfpc; 66 { 67 register u_short *frompcindex; 68 register struct tostruct *top, *prevtop; 69 register struct gmonparam *p; 70 register long toindex; 71 #ifdef _KERNEL 72 register int s; 73 #endif 74 75 p = &_gmonparam; 76 /* 77 * check that we are profiling 78 * and that we aren't recursively invoked. 79 */ 80 if (p->state != GMON_PROF_ON) 81 return; 82 #ifdef _KERNEL 83 MCOUNT_ENTER; 84 #else 85 p->state = GMON_PROF_BUSY; 86 #endif 87 /* 88 * check that frompcindex is a reasonable pc value. 89 * for example: signal catchers get called from the stack, 90 * not from text space. too bad. 91 */ 92 frompc -= p->lowpc; 93 if (frompc > p->textsize) 94 goto done; 95 96 #if (HASHFRACTION & (HASHFRACTION - 1)) == 0 97 if (p->hashfraction == HASHFRACTION) 98 frompcindex = 99 &p->froms[frompc / (HASHFRACTION * sizeof(*p->froms))]; 100 else 101 #endif 102 frompcindex = 103 &p->froms[frompc / (p->hashfraction * sizeof(*p->froms))]; 104 toindex = *frompcindex; 105 if (toindex == 0) { 106 /* 107 * first time traversing this arc 108 */ 109 toindex = ++p->tos[0].link; 110 if (toindex >= p->tolimit) 111 /* halt further profiling */ 112 goto overflow; 113 114 *frompcindex = toindex; 115 top = &p->tos[toindex]; 116 top->selfpc = selfpc; 117 top->count = 1; 118 top->link = 0; 119 goto done; 120 } 121 top = &p->tos[toindex]; 122 if (top->selfpc == selfpc) { 123 /* 124 * arc at front of chain; usual case. 125 */ 126 top->count++; 127 goto done; 128 } 129 /* 130 * have to go looking down chain for it. 131 * top points to what we are looking at, 132 * prevtop points to previous top. 133 * we know it is not at the head of the chain. 134 */ 135 for (; /* goto done */; ) { 136 if (top->link == 0) { 137 /* 138 * top is end of the chain and none of the chain 139 * had top->selfpc == selfpc. 140 * so we allocate a new tostruct 141 * and link it to the head of the chain. 142 */ 143 toindex = ++p->tos[0].link; 144 if (toindex >= p->tolimit) 145 goto overflow; 146 147 top = &p->tos[toindex]; 148 top->selfpc = selfpc; 149 top->count = 1; 150 top->link = *frompcindex; 151 *frompcindex = toindex; 152 goto done; 153 } 154 /* 155 * otherwise, check the next arc on the chain. 156 */ 157 prevtop = top; 158 top = &p->tos[top->link]; 159 if (top->selfpc == selfpc) { 160 /* 161 * there it is. 162 * increment its count 163 * move it to the head of the chain. 164 */ 165 top->count++; 166 toindex = prevtop->link; 167 prevtop->link = top->link; 168 top->link = *frompcindex; 169 *frompcindex = toindex; 170 goto done; 171 } 172 173 } 174 done: 175 #ifdef _KERNEL 176 MCOUNT_EXIT; 177 #else 178 p->state = GMON_PROF_ON; 179 #endif 180 return; 181 overflow: 182 p->state = GMON_PROF_ERROR; 183 #ifdef _KERNEL 184 MCOUNT_EXIT; 185 #endif 186 return; 187 } 188 189 /* 190 * Actual definition of mcount function. Defined in <machine/profile.h>, 191 * which is included by <sys/gmon.h>. 192 */ 193 MCOUNT 194