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 sccsid[] = "@(#)mcount.c 8.1 (Berkeley) 6/4/93"; 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(frompc, selfpc) /* _mcount; may be static, inline, etc */ 57 register u_long frompc, selfpc; 58 { 59 register u_short *frompcindex; 60 register struct tostruct *top, *prevtop; 61 register struct gmonparam *p; 62 register long toindex; 63 #ifdef KERNEL 64 register int s; 65 #endif 66 67 p = &_gmonparam; 68 /* 69 * check that we are profiling 70 * and that we aren't recursively invoked. 71 */ 72 if (p->state != GMON_PROF_ON) 73 return; 74 #ifdef KERNEL 75 MCOUNT_ENTER; 76 #else 77 p->state = GMON_PROF_BUSY; 78 #endif 79 /* 80 * check that frompcindex is a reasonable pc value. 81 * for example: signal catchers get called from the stack, 82 * not from text space. too bad. 83 */ 84 frompc -= p->lowpc; 85 if (frompc > p->textsize) 86 goto done; 87 88 frompcindex = &p->froms[frompc / (p->hashfraction * sizeof(*p->froms))]; 89 toindex = *frompcindex; 90 if (toindex == 0) { 91 /* 92 * first time traversing this arc 93 */ 94 toindex = ++p->tos[0].link; 95 if (toindex >= p->tolimit) 96 /* halt further profiling */ 97 goto overflow; 98 99 *frompcindex = toindex; 100 top = &p->tos[toindex]; 101 top->selfpc = selfpc; 102 top->count = 1; 103 top->link = 0; 104 goto done; 105 } 106 top = &p->tos[toindex]; 107 if (top->selfpc == selfpc) { 108 /* 109 * arc at front of chain; usual case. 110 */ 111 top->count++; 112 goto done; 113 } 114 /* 115 * have to go looking down chain for it. 116 * top points to what we are looking at, 117 * prevtop points to previous top. 118 * we know it is not at the head of the chain. 119 */ 120 for (; /* goto done */; ) { 121 if (top->link == 0) { 122 /* 123 * top is end of the chain and none of the chain 124 * had top->selfpc == selfpc. 125 * so we allocate a new tostruct 126 * and link it to the head of the chain. 127 */ 128 toindex = ++p->tos[0].link; 129 if (toindex >= p->tolimit) 130 goto overflow; 131 132 top = &p->tos[toindex]; 133 top->selfpc = selfpc; 134 top->count = 1; 135 top->link = *frompcindex; 136 *frompcindex = toindex; 137 goto done; 138 } 139 /* 140 * otherwise, check the next arc on the chain. 141 */ 142 prevtop = top; 143 top = &p->tos[top->link]; 144 if (top->selfpc == selfpc) { 145 /* 146 * there it is. 147 * increment its count 148 * move it to the head of the chain. 149 */ 150 top->count++; 151 toindex = prevtop->link; 152 prevtop->link = top->link; 153 top->link = *frompcindex; 154 *frompcindex = toindex; 155 goto done; 156 } 157 158 } 159 done: 160 #ifdef KERNEL 161 MCOUNT_EXIT; 162 #else 163 p->state = GMON_PROF_ON; 164 #endif 165 return; 166 overflow: 167 p->state = GMON_PROF_ERROR; 168 #ifdef KERNEL 169 MCOUNT_EXIT; 170 #endif 171 return; 172 } 173 174 /* 175 * Actual definition of mcount function. Defined in <machine/profile.h>, 176 * which is included by <sys/gmon.h>. 177 */ 178 MCOUNT 179