/* Copyright (C) 2001-2018 Free Software Foundation, Inc.

   Contributed by David Mosberger-Tang <davidm@hpl.hp.com>.

   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

#include <assert.h>

#include <signal.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

#include <sigsetops.h>

#include <sys/time.h>

#include <sys/profil.h>

#ifndef SIGPROF

# include <gmon/sprofil.c>

#else

#include <libc-internal.h>

struct region

  {

    size_t offset;

    size_t nsamples;

    unsigned int scale;

    union

      {

	void *vp;

	unsigned short *us;

	unsigned int *ui;

      }

    sample;

    size_t start;

    size_t end;

  };

struct prof_info

  {

    unsigned int num_regions;

    struct region *region;

    struct region *last, *overflow;

    struct itimerval saved_timer;

    struct sigaction saved_action;

  };

static unsigned int overflow_counter;

static struct region default_overflow_region =

  {

    .offset	= 0,

    .nsamples	= 1,

    .scale	= 2,

    .sample	= { &overflow_counter },

    .start	= 0,

    .end	= ~(size_t) 0

  };

static struct prof_info prof_info;

static unsigned long int

pc_to_index (size_t pc, size_t offset, unsigned int scale, int prof_uint)

{

  size_t i = (pc - offset) / (prof_uint ? sizeof (int) : sizeof (short));

  if (sizeof (unsigned long long int) > sizeof (size_t))

    return (unsigned long long int) i * scale / 65536;

  else

    return i / 65536 * scale + i % 65536 * scale / 65536;

}

static inline size_t

index_to_pc (unsigned long int n, size_t offset, unsigned int scale,

	     int prof_uint)

{

  size_t pc, bin_size = (prof_uint ? sizeof (int) : sizeof (short));

  if (sizeof (unsigned long long int) > sizeof (size_t))

    pc = offset + (unsigned long long int) n * bin_size * 65536ull / scale;

  else

    pc = (offset + n * bin_size / scale * 65536

	  + n * bin_size % scale * 65536 / scale);

  if (pc_to_index (pc, offset, scale, prof_uint) < n)

    /* Adjust for rounding error.  */

    ++pc;

  assert (pc_to_index (pc - 1, offset, scale, prof_uint) < n

	  && pc_to_index (pc, offset, scale, prof_uint) >= n);

  return pc;

}

static void

profil_count (void *pcp, int prof_uint)

{

  struct region *region, *r = prof_info.last;

  size_t lo, hi, mid, pc = (unsigned long int) pcp;

  unsigned long int i;

  /* Fast path: pc is in same region as before.  */

  if (pc >= r->start && pc < r->end)

    region = r;

  else

    {

      /* Slow path: do a binary search for the right region.  */

      lo = 0; hi = prof_info.num_regions - 1;

      while (lo <= hi)

	{

	  mid = (lo + hi) / 2;

	  r = prof_info.region + mid;

	  if (pc >= r->start && pc < r->end)

	    {

	      prof_info.last = r;

	      region = r;

	      break;

	    }

	  if (pc < r->start)

	    hi = mid - 1;

	  else

	    lo = mid + 1;

	}

      /* No matching region: increment overflow count.  There is no point

	 in updating the cache here, as it won't hit anyhow.  */

      region = prof_info.overflow;

    }

  i = pc_to_index (pc, region->offset, region->scale, prof_uint);

  if (i < r->nsamples)

    {

      if (prof_uint)

	{

	  if (r->sample.ui[i] < (unsigned int) ~0)

	    ++r->sample.ui[i];

	}

      else

	{

	  if (r->sample.us[i] < (unsigned short) ~0)

	    ++r->sample.us[i];

	}

    }

  else

    {

      if (prof_uint)

	++prof_info.overflow->sample.ui[0];

      else

	++prof_info.overflow->sample.us[0];

    }

}

static inline void

profil_count_ushort (void *pcp)

{

  profil_count (pcp, 0);

}

static inline void

profil_count_uint (void *pcp)

{

  profil_count (pcp, 1);

}

/* Get the machine-dependent definition of `__profil_counter', the signal

   handler for SIGPROF.  It calls `profil_count' (above) with the PC of the

   interrupted code.  */

#define __profil_counter	__profil_counter_ushort

#define profil_count(pc)	profil_count (pc, 0)

#include <profil-counter.h>

#undef __profil_counter

#undef profil_count

#define __profil_counter	__profil_counter_uint

#define profil_count(pc)	profil_count (pc, 1)

#include <profil-counter.h>

static int

insert (int i, unsigned long int start, unsigned long int end, struct prof *p,

	int prof_uint)

{

  struct region *r;

  size_t to_copy;

  if (start >= end)

    return 0;		/* don't bother with empty regions */

  if (prof_info.num_regions == 0)

    r = malloc (sizeof (*r));

  else

    r = realloc (prof_info.region, (prof_info.num_regions + 1) * sizeof (*r));

  if (r == NULL)

    return -1;

  to_copy = prof_info.num_regions - i;

  if (to_copy > 0)

    memmove (r + i + 1, r + i, to_copy * sizeof (*r));

  r[i].offset = p->pr_off;

  r[i].nsamples = p->pr_size / (prof_uint ? sizeof (int) : sizeof (short));

  r[i].scale = p->pr_scale;

  r[i].sample.vp = p->pr_base;

  r[i].start = start;

  r[i].end = end;

  prof_info.region = r;

  ++prof_info.num_regions;

  if (p->pr_off == 0 && p->pr_scale == 2)

    prof_info.overflow = r;

  return 0;

}

/* Add a new profiling region.  If the new region overlaps with

   existing ones, this may add multiple subregions so that the final

   data structure is free of overlaps.  The absence of overlaps makes

   it possible to use a binary search in profil_count().  Note that

   this function depends on new regions being presented in DECREASING

   ORDER of starting address.  */

static int

add_region (struct prof *p, int prof_uint)

{

  unsigned long int nsamples;

  size_t start, end;

  unsigned int i;

  if (p->pr_scale < 2)

    return 0;

  nsamples = p->pr_size / (prof_uint ? sizeof (int) : sizeof (short));

  start = p->pr_off;

  end = index_to_pc (nsamples, p->pr_off, p->pr_scale, prof_uint);

  /* Merge with existing regions.  */

  for (i = 0; i < prof_info.num_regions; ++i)

    {

      if (start < prof_info.region[i].start)

	{

	  if (end < prof_info.region[i].start)

	    break;

	  else if (insert (i, start, prof_info.region[i].start, p, prof_uint)

		   < 0)

	    return -1;

	}

      start = prof_info.region[i].end;

    }

  return insert (i, start, end, p, prof_uint);

}

static int

pcmp (const void *left, const void *right)

{

  struct prof *l = *(struct prof **) left;

  struct prof *r = *(struct prof **) right;

  if (l->pr_off < r->pr_off)

    return 1;

  else if (l->pr_off > r->pr_off)

    return -1;

  return 0;

}

int

__sprofil (struct prof *profp, int profcnt, struct timeval *tvp,

	   unsigned int flags)

{

  struct prof *p[profcnt];

  struct itimerval timer;

  struct sigaction act;

  int i;

  if (tvp != NULL)

    {

      /* Return profiling period.  */

      unsigned long int t = 1000000 / __profile_frequency ();

      tvp->tv_sec  = t / 1000000;

      tvp->tv_usec = t % 1000000;

    }

  if (prof_info.num_regions > 0)

    {

      /* Disable profiling.  */

      if (__setitimer (ITIMER_PROF, &prof_info.saved_timer, NULL) < 0)

	return -1;

      if (__sigaction (SIGPROF, &prof_info.saved_action, NULL) < 0)

	return -1;

      free (prof_info.region);

      return 0;

    }

  prof_info.num_regions = 0;

  prof_info.region = NULL;

  prof_info.overflow = &default_overflow_region;

  for (i = 0; i < profcnt; ++i)

    p[i] = profp + i;

  /* Sort in order of decreasing starting address: */

  qsort (p, profcnt, sizeof (p[0]), pcmp);

  /* Add regions in order of decreasing starting address: */

  for (i = 0; i < profcnt; ++i)

    if (add_region (p[i], (flags & PROF_UINT) != 0) < 0)

      {

	free (prof_info.region);

	prof_info.num_regions = 0;

	prof_info.region = NULL;

	return -1;

      }

  if (prof_info.num_regions == 0)

    return 0;

  prof_info.last = prof_info.region;

  /* Install SIGPROF handler.  */

  if (flags & PROF_UINT)

    act.sa_handler = (sighandler_t) &__profil_counter_uint;

  else

    act.sa_handler = (sighandler_t) &__profil_counter_ushort;

  act.sa_flags = SA_RESTART;

  __sigfillset (&act.sa_mask);

  if (__sigaction (SIGPROF, &act, &prof_info.saved_action) < 0)

    return -1;

  /* Setup profiling timer.  */

  timer.it_value.tv_sec  = 0;

  timer.it_value.tv_usec = 1;

  timer.it_interval = timer.it_value;

  return __setitimer (ITIMER_PROF, &timer, &prof_info.saved_timer);

}

weak_alias (__sprofil, sprofil)

#endif /* SIGPROF */