winsup/cygwin/mcount.c

   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  * 4. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 #if !defined(lint) && !defined(_KERNEL) && defined(LIBC_SCCS)
  31 static char rcsid[] = "$OpenBSD: mcount.c,v 1.6 1997/07/23 21:11:27 kstailey Exp $";
  32 #endif
  33
  34 /*
  35  * This file is taken from Cygwin distribution. Please keep it in sync.
  36  * The differences should be within __MINGW32__ guard.
  37  */
  38
  39 #ifndef __MINGW32__
  40 #include <sys/param.h>
  41 #endif
  42 #include <sys/types.h>
  43 #include "gmon.h"
  44 #include "winsup.h"
  45
  46 /*
  47  * mcount is called on entry to each function compiled with the profiling
  48  * switch set.  _mcount(), which is declared in a machine-dependent way
  49  * with _MCOUNT_DECL, does the actual work and is either inlined into a
  50  * C routine or called by an assembly stub.  In any case, this magic is
  51  * taken care of by the MCOUNT definition in <machine/profile.h>.
  52  *
  53  * _mcount updates data structures that represent traversals of the
  54  * program's call graph edges.  frompc and selfpc are the return
  55  * address and function address that represents the given call graph edge.
  56  *
  57  * Note: the original BSD code used the same variable (frompcindex) for
  58  * both frompcindex and frompc.  Any reasonable, modern compiler will
  59  * perform this optimization.
  60  */
  61 /* _mcount; may be static, inline, etc */
  62 _MCOUNT_DECL (size_t, size_t);
  63
  64 _MCOUNT_DECL (size_t frompc, size_t selfpc)
  65 {
  66         register u_int16_t *frompcindex;
  67         register struct tostruct *top, *prevtop;
  68         register struct gmonparam *p;
  69         register long toindex;
  70
  71         p = &_gmonparam;
  72         /*
  73          * check that we are profiling
  74          * and that we aren't recursively invoked by this thread
  75          * or entered anew by any other thread.
  76          */
  77         if (InterlockedCompareExchange (
  78                     &p->state, GMON_PROF_BUSY, GMON_PROF_ON) != GMON_PROF_ON)
  79                 return;
  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 done:
 167         InterlockedExchange (&p->state, GMON_PROF_ON);
 168         return;
 169 overflow:
 170         InterlockedExchange (&p->state, GMON_PROF_ERROR);
 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