glibc/gmon/gmon.c

/*-
 * Copyright (c) 1983, 1992, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */
#include <sys/param.h>
#include <sys/time.h>
#include <sys/gmon.h>
#include <sys/gmon_out.h>

#include <ansidecl.h>
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

struct __bb *__bb_head;	/*  Head of basic-block list or NULL. */

struct gmonparam _gmonparam = { GMON_PROF_OFF };

/*
 * See profil(2) where this is described:
 */
static int	s_scale;
#define		SCALE_1_TO_1	0x10000L

#define ERR(s) write(2, s, sizeof(s))

/*
 * Discover the tick frequency of the machine if something goes wrong,
 * we return 0, an impossible hertz.
 */
static int
DEFUN_VOID(hertz)
{
  struct itimerval tim;
    
  tim.it_interval.tv_sec = 0;
  tim.it_interval.tv_usec = 1;
  tim.it_value.tv_sec = 0;
  tim.it_value.tv_usec = 0;
  setitimer(ITIMER_REAL, &tim, 0);
  setitimer(ITIMER_REAL, 0, &tim);
  if (tim.it_interval.tv_usec < 2)
    return 0;
  return (1000000 / tim.it_interval.tv_usec);
}


/*
 * Control profiling
 *	profiling is what mcount checks to see if
 *	all the data structures are ready.
 */
void
DEFUN(moncontrol, (mode), int mode)
{
  struct gmonparam *p = &_gmonparam;

  if (mode)
    {
      /* start */
      profil((void *) p->kcount, p->kcountsize, p->lowpc, s_scale);
      p->state = GMON_PROF_ON;
    }
  else
    {
      /* stop */
      profil((void *) 0, 0, 0, 0);
      p->state = GMON_PROF_OFF;
    }
}


void
DEFUN(monstartup, (lowpc, highpc), u_long lowpc AND u_long highpc)
{
  register int o;
  char *cp;
  struct gmonparam *p = &_gmonparam;

  /*
   * round lowpc and highpc to multiples of the density we're using
   * so the rest of the scaling (here and in gprof) stays in ints.
   */
  p->lowpc = ROUNDDOWN(lowpc, HISTFRACTION * sizeof(HISTCOUNTER));
  p->highpc = ROUNDUP(highpc, HISTFRACTION * sizeof(HISTCOUNTER));
  p->textsize = p->highpc - p->lowpc;
  p->kcountsize = p->textsize / HISTFRACTION;
  p->hashfraction = HASHFRACTION;
  p->log_hashfraction = -1;
  if ((HASHFRACTION & (HASHFRACTION - 1)) == 0) {
      /* if HASHFRACTION is a power of two, mcount can use shifting
	 instead of integer division.  Precompute shift amount. */
      p->log_hashfraction = ffs(p->hashfraction * sizeof(*p->froms)) - 1;
  }
  p->fromssize = p->textsize / HASHFRACTION;
  p->tolimit = p->textsize * ARCDENSITY / 100;
  if (p->tolimit < MINARCS)
    p->tolimit = MINARCS;
  else if (p->tolimit > MAXARCS)
    p->tolimit = MAXARCS;
  p->tossize = p->tolimit * sizeof(struct tostruct);

  cp = malloc (p->kcountsize + p->fromssize + p->tossize);
  if (! cp)
    {
      ERR("monstartup: out of memory\n");
      return;
    }
  bzero(cp, p->kcountsize + p->fromssize + p->tossize);
  p->tos = (struct tostruct *)cp;
  cp += p->tossize;
  p->kcount = (u_short *)cp;
  cp += p->kcountsize;
  p->froms = (u_short *)cp;

  p->tos[0].link = 0;

  o = p->highpc - p->lowpc;
  if (p->kcountsize < o)
    {
#ifndef hp300
      s_scale = ((float)p->kcountsize / o ) * SCALE_1_TO_1;
#else
      /* avoid floating point operations */
      int quot = o / p->kcountsize;

      if (quot >= 0x10000)
	s_scale = 1;
      else if (quot >= 0x100)
	s_scale = 0x10000 / quot;
      else if (o >= 0x800000)
	s_scale = 0x1000000 / (o / (p->kcountsize >> 8));
      else
	s_scale = 0x1000000 / ((o << 8) / p->kcountsize);
#endif
    } else
      s_scale = SCALE_1_TO_1;

  moncontrol(1);
}


static void
DEFUN(write_hist, (fd), int fd)
{
  const u_char tag = GMON_TAG_TIME_HIST;
  struct gmon_hist_hdr thdr;
  int size, rate;

  if (_gmonparam.kcountsize > 0)
    {
      size = _gmonparam.kcountsize / sizeof(HISTCOUNTER);
      rate = hertz();
      bcopy(&_gmonparam.lowpc, &thdr.low_pc, sizeof(thdr.low_pc));
      bcopy(&_gmonparam.highpc, &thdr.high_pc, sizeof(thdr.high_pc));
      bcopy(&size, &thdr.hist_size, sizeof(thdr.hist_size));
      bcopy(&rate, &thdr.prof_rate, sizeof(thdr.prof_rate));
      strcpy(thdr.dimen, "seconds");
      thdr.dimen_abbrev = 's';

      write(fd, &tag, sizeof(tag));
      write(fd, &thdr, sizeof(thdr));
      write(fd, _gmonparam.kcount, _gmonparam.kcountsize);
    }
}


static void
DEFUN(write_call_graph, (fd), int fd)
{
  const u_char tag = GMON_TAG_CG_ARC;
  struct gmon_cg_arc_record raw_arc;
  int from_index, to_index, from_len;
  u_long frompc;

  from_len = _gmonparam.fromssize / sizeof(*_gmonparam.froms);
  for (from_index = 0; from_index < from_len; ++from_index)
    {
      if (_gmonparam.froms[from_index] == 0)
	continue;

      frompc = _gmonparam.lowpc;
      frompc += (from_index * _gmonparam.hashfraction
		 * sizeof(*_gmonparam.froms));
      for (to_index = _gmonparam.froms[from_index];
	   to_index != 0;
	   to_index = _gmonparam.tos[to_index].link)
	{
	  bcopy(&frompc, &raw_arc.from_pc, sizeof(raw_arc.from_pc));
	  bcopy(&_gmonparam.tos[to_index].selfpc, &raw_arc.self_pc,
		sizeof(raw_arc.self_pc));
	  bcopy(&_gmonparam.tos[to_index].count, &raw_arc.count,
		sizeof(raw_arc.count));

	  write(fd, &tag, sizeof(tag));
	  write(fd, &raw_arc, sizeof(raw_arc));
	}
    }
}


static void
DEFUN(write_bb_counts, (fd), int fd)
{
  struct __bb *grp;
  const u_char tag = GMON_TAG_BB_COUNT;
  int ncounts;
  int i;

  /* Write each group of basic-block info (all basic-blocks in a
     compilation unit form a single group). */

  for (grp = __bb_head; grp; grp = grp->next)
    {
      ncounts = grp->ncounts;
      write(fd, &tag, sizeof(tag));
      write(fd, &ncounts, sizeof(ncounts));
      for (i = 0; i < ncounts; ++i)
	{
	  write(fd, &grp->addresses[i], sizeof(grp->addresses[0]));
	  write(fd, &grp->counts[i], sizeof(grp->counts[0]));
	}
    }
}


void
DEFUN_VOID(_mcleanup)
{
    const int version = GMON_VERSION;
    struct gmon_hdr ghdr;
    int fd;

    moncontrol(0);
    fd = open("gmon.out", O_CREAT|O_TRUNC|O_WRONLY, 0666);
    if (fd < 0)
      {
	perror("_mcleanup: gmon.out");
	return;
      }

    /* write gmon.out header: */
    bcopy(GMON_MAGIC, &ghdr.cookie[0], 4);
    bcopy(&version, &ghdr.version, sizeof(version));
    write(fd, &ghdr, sizeof(ghdr));

    /* write PC histogram: */
    write_hist(fd);

    /* write call-graph: */
    write_call_graph(fd);

    /* write basic-block execution counts: */
    write_bb_counts(fd);

    close(fd);
}