libgcc/config/arc/gmon/mcount.c

   1 /*-
   2  * Copyright (c) 1983, 1992, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Copyright (C) 2007-2013 Free Software Foundation, Inc.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 4. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 #if !defined(lint) && !defined(KERNEL) && defined(LIBC_SCCS)
  33 static char sccsid[] = "@(#)mcount.c    8.1 (Berkeley) 6/4/93";
  34 #endif
  35
  36 #if 0
  37 #include <unistd.h>
  38 #include <sys/param.h>
  39 #endif
  40 #include <sys/gmon.h>
  41
  42 /* This file provides the machine-dependent definitions of the _MCOUNT_DECL
  43    and MCOUNT macros.  */
  44 #include <machine-gmon.h>
  45
  46 #include <atomic.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(count_ptr, selfpc) /* _mcount; may be static, inline, etc */
  64 {
  65         register ARCINDEX *frompcindex;
  66         register struct tostruct *top, *prevtop;
  67         register struct gmonparam *p;
  68         register ARCINDEX toindex;
  69
  70         /* Check for nested function trampoline.  */
  71         if (selfpc & 2)
  72           selfpc = *(u_long *) (selfpc + 10);
  73
  74         p = &_gmonparam;
  75         /*
  76          * check that we are profiling
  77          * and that we aren't recursively invoked.
  78          */
  79 #if 0
  80         if (catomic_compare_and_exchange_bool_acq (&p->state, GMON_PROF_BUSY,
  81                                                    GMON_PROF_ON))
  82           return;
  83 #elif defined (__ARC700__)
  84 /* ??? This could temporarily lose the ERROR / OFF condition in a race,
  85    but doing an actual compare_and_exchange would be too costly.  It would
  86    be better if we had a semaphore independent of the 'sticky' state, but
  87    then we could run into ABI compatibility problems with the size of struct
  88    gmonparam.  */
  89         {
  90           u_long old_state;
  91
  92           __asm ("ex %0,%1": "=r" (old_state), "+m" (p->state)
  93                  : "0" (GMON_PROF_BUSY));
  94           if (old_state != GMON_PROF_ON)
  95             {
  96               switch (old_state)
  97                 {
  98                 case GMON_PROF_OFF:
  99                   __asm ("ex %0,%1": "+r" (old_state), "+m" (p->state));
 100                   if (old_state == GMON_PROF_BUSY
 101                       /* Switching off while we say we are busy while profiling
 102                          was actually already switched off is all right.  */
 103                       || old_state == GMON_PROF_OFF)
 104                     break;
 105                   /* It is not clear if we should allow switching on
 106                      profiling at this point, and how to handle further races.
 107                      For now, record an error in this case.  */
 108                   /* Fall through.  */
 109                 default: /* We expect here only GMON_PROF_ERROR.  */
 110                   p->state = GMON_PROF_ERROR;
 111                   break;
 112                 case GMON_PROF_BUSY: break;
 113                 }
 114               return;
 115             }
 116         }
 117 #else /* ??? No semaphore primitives available.  */
 118         if (p->state != GMON_PROF_ON)
 119           return;
 120         p->state = GMON_PROF_BUSY;
 121 #endif
 122
 123         frompcindex = count_ptr;
 124         toindex = *frompcindex;
 125         if (toindex == 0) {
 126                 /*
 127                  *      first time traversing this arc
 128                  */
 129                 toindex = ++p->tos[0].link;
 130                 if (toindex >= (ARCINDEX) p->tolimit)
 131                         /* halt further profiling */
 132                         goto overflow;
 133
 134                 *frompcindex = toindex;
 135                 top = &p->tos[toindex];
 136                 top->selfpc = selfpc;
 137                 top->count = 1;
 138                 top->link = 0;
 139                 goto done;
 140         }
 141         top = &p->tos[toindex];
 142         if (top->selfpc == selfpc) {
 143                 /*
 144                  * arc at front of chain; usual case.
 145                  */
 146                 top->count++;
 147                 goto done;
 148         }
 149         /*
 150          * have to go looking down chain for it.
 151          * top points to what we are looking at,
 152          * prevtop points to previous top.
 153          * we know it is not at the head of the chain.
 154          */
 155         for (; /* goto done */; ) {
 156                 if (top->link == 0) {
 157                         /*
 158                          * top is end of the chain and none of the chain
 159                          * had top->selfpc == selfpc.
 160                          * so we allocate a new tostruct
 161                          * and link it to the head of the chain.
 162                          */
 163                         toindex = ++p->tos[0].link;
 164                         if (toindex >= (ARCINDEX) p->tolimit)
 165                                 goto overflow;
 166
 167                         top = &p->tos[toindex];
 168                         top->selfpc = selfpc;
 169                         top->count = 1;
 170                         top->link = *frompcindex;
 171                         *frompcindex = toindex;
 172                         goto done;
 173                 }
 174                 /*
 175                  * otherwise, check the next arc on the chain.
 176                  */
 177                 prevtop = top;
 178                 top = &p->tos[top->link];
 179                 if (top->selfpc == selfpc) {
 180                         /*
 181                          * there it is.
 182                          * increment its count
 183                          * move it to the head of the chain.
 184                          */
 185                         top->count++;
 186                         toindex = prevtop->link;
 187                         prevtop->link = top->link;
 188                         top->link = *frompcindex;
 189                         *frompcindex = toindex;
 190                         goto done;
 191                 }
 192
 193         }
 194 done:
 195         p->state = GMON_PROF_ON;
 196         return;
 197 overflow:
 198         p->state = GMON_PROF_ERROR;
 199         return;
 200 }
 201
 202 /*
 203  * Actual definition of mcount function.  Defined in <machine/profile.h>,
 204  * which is included by <sys/gmon.h>.
 205  */
 206 MCOUNT