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 #ifdef KERNEL 41 #include <i386/include/cpufunc.h> 42 #endif 43 44 /* 45 * mcount is called on entry to each function compiled with the profiling 46 * switch set. _mcount(), which is declared in a machine-dependent way 47 * with _MCOUNT_DECL, does the actual work and is either inlined into a 48 * C routine or called by an assembly stub. In any case, this magic is 49 * taken care of by the MCOUNT definition in <machine/profile.h>. 50 * 51 * _mcount updates data structures that represent traversals of the 52 * program's call graph edges. frompc and selfpc are the return 53 * address and function address that represents the given call graph edge. 54 * 55 * Note: the original BSD code used the same variable (frompcindex) for 56 * both frompcindex and frompc. Any reasonable, modern compiler will 57 * perform this optimization. 58 */ 59 _MCOUNT_DECL(frompc, selfpc) /* _mcount; may be static, inline, etc */ 60 register u_long frompc, selfpc; 61 { 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 u_long save_eflags; 69 #endif 70 71 p = &_gmonparam; 72 /* 73 * check that we are profiling 74 * and that we aren't recursively invoked. 75 */ 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 83 /* 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. 87 */ 88 frompc -= p->lowpc; 89 if (frompc > p->textsize) 90 goto done; 91 92 frompcindex = &p->froms[frompc / (p->hashfraction * sizeof(*p->froms))]; 93 toindex = *frompcindex; 94 if (toindex == 0) { 95 /* 96 * first time traversing this arc 97 */ 98 toindex = ++p->tos[0].link; 99 if (toindex >= p->tolimit) 100 /* halt further profiling */ 101 goto overflow; 102 103 *frompcindex = toindex; 104 top = &p->tos[toindex]; 105 top->selfpc = selfpc; 106 top->count = 1; 107 top->link = 0; 108 goto done; 109 } 110 top = &p->tos[toindex]; 111 if (top->selfpc == selfpc) { 112 /* 113 * arc at front of chain; usual case. 114 */ 115 top->count++; 116 goto done; 117 } 118 /* 119 * have to go looking down chain for it. 120 * top points to what we are looking at, 121 * prevtop points to previous top. 122 * we know it is not at the head of the chain. 123 */ 124 for (; /* goto done */; ) { 125 if (top->link == 0) { 126 /* 127 * top is end of the chain and none of the chain 128 * had top->selfpc == selfpc. 129 * so we allocate a new tostruct 130 * and link it to the head of the chain. 131 */ 132 toindex = ++p->tos[0].link; 133 if (toindex >= p->tolimit) 134 goto overflow; 135 136 top = &p->tos[toindex]; 137 top->selfpc = selfpc; 138 top->count = 1; 139 top->link = *frompcindex; 140 *frompcindex = toindex; 141 goto done; 142 } 143 /* 144 * otherwise, check the next arc on the chain. 145 */ 146 prevtop = top; 147 top = &p->tos[top->link]; 148 if (top->selfpc == selfpc) { 149 /* 150 * there it is. 151 * increment its count 152 * move it to the head of the chain. 153 */ 154 top->count++; 155 toindex = prevtop->link; 156 prevtop->link = top->link; 157 top->link = *frompcindex; 158 *frompcindex = toindex; 159 goto done; 160 } 161 162 } 163 done: 164 #ifdef KERNEL 165 MCOUNT_EXIT; 166 #else 167 p->state = GMON_PROF_ON; 168 #endif 169 return; 170 overflow: 171 p->state = GMON_PROF_ERROR; 172 #ifdef KERNEL 173 MCOUNT_EXIT; 174 #endif 175 return; 176 } 177 178 /* 179 * Actual definition of mcount function. Defined in <machine/profile.h>, 180 * which is included by <sys/gmon.h>. 181 */ 182 MCOUNT 183