libgcov-driver.c

/* Routines required for instrumenting a program.  */
/* Compile this one with gcc.  */
/* Copyright (C) 1989-2016 Free Software Foundation, Inc.

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.

GCC 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 General Public License
for more details.

Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.

You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
<http://www.gnu.org/licenses/>.  */

#include "libgcov.h"

#if defined(inhibit_libc)
/* If libc and its header files are not available, provide dummy functions.  */

#if defined(L_gcov)
void __gcov_init (struct gcov_info *p __attribute__ ((unused))) {}
#endif

#else /* inhibit_libc */

#include <string.h>
#if GCOV_LOCKED
#include <fcntl.h>
#include <errno.h>
#include <sys/stat.h>
#endif

#ifdef L_gcov

/* A utility function for outputing errors.  */
static int gcov_error (const char *, ...);

#include "gcov-io.c"

struct gcov_fn_buffer
{
  struct gcov_fn_buffer *next;
  unsigned fn_ix;
  struct gcov_fn_info info;
  /* note gcov_fn_info ends in a trailing array.  */
};

struct gcov_summary_buffer
{
  struct gcov_summary_buffer *next;
  struct gcov_summary summary;
};

/* A struct that bundles all the related information about the
   gcda filename.  */

struct gcov_filename
{
  char *filename;  /* filename buffer */
  size_t max_length;  /* maximum filename length */
  int strip; /* leading chars to strip from filename */
  size_t prefix; /* chars to prepend to filename */
};

static struct gcov_fn_buffer *
free_fn_data (const struct gcov_info *gi_ptr, struct gcov_fn_buffer *buffer,
              unsigned limit)
{
  struct gcov_fn_buffer *next;
  unsigned ix, n_ctr = 0;

  if (!buffer)
    return 0;
  next = buffer->next;

  for (ix = 0; ix != limit; ix++)
    if (gi_ptr->merge[ix])
      free (buffer->info.ctrs[n_ctr++].values);
  free (buffer);
  return next;
}

static struct gcov_fn_buffer **
buffer_fn_data (const char *filename, const struct gcov_info *gi_ptr,
                struct gcov_fn_buffer **end_ptr, unsigned fn_ix)
{
  unsigned n_ctrs = 0, ix = 0;
  struct gcov_fn_buffer *fn_buffer;
  unsigned len;

  for (ix = GCOV_COUNTERS; ix--;)
    if (gi_ptr->merge[ix])
      n_ctrs++;

  len = sizeof (*fn_buffer) + sizeof (fn_buffer->info.ctrs[0]) * n_ctrs;
  fn_buffer = (struct gcov_fn_buffer *) xmalloc (len);

  if (!fn_buffer)
    goto fail;

  fn_buffer->next = 0;
  fn_buffer->fn_ix = fn_ix;
  fn_buffer->info.ident = gcov_read_unsigned ();
  fn_buffer->info.lineno_checksum = gcov_read_unsigned ();
  fn_buffer->info.cfg_checksum = gcov_read_unsigned ();

  for (n_ctrs = ix = 0; ix != GCOV_COUNTERS; ix++)
    {
      gcov_unsigned_t length;
      gcov_type *values;

      if (!gi_ptr->merge[ix])
        continue;

      if (gcov_read_unsigned () != GCOV_TAG_FOR_COUNTER (ix))
        {
          len = 0;
          goto fail;
        }

      length = GCOV_TAG_COUNTER_NUM (gcov_read_unsigned ());
      len = length * sizeof (gcov_type);
      values = (gcov_type *) xmalloc (len);
      if (!values)
        goto fail;

      fn_buffer->info.ctrs[n_ctrs].num = length;
      fn_buffer->info.ctrs[n_ctrs].values = values;

      while (length--)
        *values++ = gcov_read_counter ();
      n_ctrs++;
    }

  *end_ptr = fn_buffer;
  return &fn_buffer->next;

fail:
  gcov_error ("profiling:%s:Function %u %s %u \n", filename, fn_ix,
              len ? "cannot allocate" : "counter mismatch", len ? len : ix);

  return (struct gcov_fn_buffer **)free_fn_data (gi_ptr, fn_buffer, ix);
}

/* Add an unsigned value to the current crc */

static gcov_unsigned_t
crc32_unsigned (gcov_unsigned_t crc32, gcov_unsigned_t value)
{
  unsigned ix;

  for (ix = 32; ix--; value <<= 1)
    {
      unsigned feedback;

      feedback = (value ^ crc32) & 0x80000000 ? 0x04c11db7 : 0;
      crc32 <<= 1;
      crc32 ^= feedback;
    }

  return crc32;
}

/* Check if VERSION of the info block PTR matches libgcov one.
   Return 1 on success, or zero in case of versions mismatch.
   If FILENAME is not NULL, its value used for reporting purposes
   instead of value from the info block.  */

static int
gcov_version (struct gcov_info *ptr, gcov_unsigned_t version,
              const char *filename)
{
  if (version != GCOV_VERSION)
    {
      char v[4], e[4];

      GCOV_UNSIGNED2STRING (v, version);
      GCOV_UNSIGNED2STRING (e, GCOV_VERSION);

      gcov_error ("profiling:%s:Version mismatch - expected %.4s got %.4s\n",
                  filename? filename : ptr->filename, e, v);
      return 0;
    }
  return 1;
}

/* Insert counter VALUE into HISTOGRAM.  */

static void
gcov_histogram_insert(gcov_bucket_type *histogram, gcov_type value)
{
  unsigned i;

  i = gcov_histo_index(value);
  histogram[i].num_counters++;
  histogram[i].cum_value += value;
  if (value < histogram[i].min_value)
    histogram[i].min_value = value;
}

/* Computes a histogram of the arc counters to place in the summary SUM.  */

static void
gcov_compute_histogram (struct gcov_info *list, struct gcov_summary *sum)
{
  struct gcov_info *gi_ptr;
  const struct gcov_fn_info *gfi_ptr;
  const struct gcov_ctr_info *ci_ptr;
  struct gcov_ctr_summary *cs_ptr;
  unsigned t_ix, f_ix, ctr_info_ix, ix;
  int h_ix;

  /* This currently only applies to arc counters.  */
  t_ix = GCOV_COUNTER_ARCS;

  /* First check if there are any counts recorded for this counter.  */
  cs_ptr = &(sum->ctrs[t_ix]);
  if (!cs_ptr->num)
    return;

  for (h_ix = 0; h_ix < GCOV_HISTOGRAM_SIZE; h_ix++)
    {
      cs_ptr->histogram[h_ix].num_counters = 0;
      cs_ptr->histogram[h_ix].min_value = cs_ptr->run_max;
      cs_ptr->histogram[h_ix].cum_value = 0;
    }

  /* Walk through all the per-object structures and record each of
     the count values in histogram.  */
  for (gi_ptr = list; gi_ptr; gi_ptr = gi_ptr->next)
    {
      if (!gi_ptr->merge[t_ix])
        continue;

      /* Find the appropriate index into the gcov_ctr_info array
         for the counter we are currently working on based on the
         existence of the merge function pointer for this object.  */
      for (ix = 0, ctr_info_ix = 0; ix < t_ix; ix++)
        {
          if (gi_ptr->merge[ix])
            ctr_info_ix++;
        }
      for (f_ix = 0; f_ix != gi_ptr->n_functions; f_ix++)
        {
          gfi_ptr = gi_ptr->functions[f_ix];

          if (!gfi_ptr || gfi_ptr->key != gi_ptr)
            continue;

          ci_ptr = &gfi_ptr->ctrs[ctr_info_ix];
          for (ix = 0; ix < ci_ptr->num; ix++)
            gcov_histogram_insert (cs_ptr->histogram, ci_ptr->values[ix]);
        }
    }
}

/* buffer for the fn_data from another program.  */
static struct gcov_fn_buffer *fn_buffer;
/* buffer for summary from other programs to be written out. */
static struct gcov_summary_buffer *sum_buffer;

/* This function computes the program level summary and the histo-gram.
   It computes and returns CRC32 and stored summary in THIS_PRG.
   Also determines the longest filename length of the info files.  */

#if !IN_GCOV_TOOL
static
#endif
gcov_unsigned_t
compute_summary (struct gcov_info *list, struct gcov_summary *this_prg,
		 size_t *max_length)
{
  struct gcov_info *gi_ptr;
  const struct gcov_fn_info *gfi_ptr;
  struct gcov_ctr_summary *cs_ptr;
  const struct gcov_ctr_info *ci_ptr;
  int f_ix;
  unsigned t_ix;
  gcov_unsigned_t c_num;
  gcov_unsigned_t crc32 = 0;

  /* Find the totals for this execution.  */
  memset (this_prg, 0, sizeof (*this_prg));
  *max_length = 0;
  for (gi_ptr = list; gi_ptr; gi_ptr = gi_ptr->next)
    {
      size_t len = strlen (gi_ptr->filename);
      if (len > *max_length)
	*max_length = len;
      
      crc32 = crc32_unsigned (crc32, gi_ptr->stamp);
      crc32 = crc32_unsigned (crc32, gi_ptr->n_functions);

      for (f_ix = 0; (unsigned)f_ix != gi_ptr->n_functions; f_ix++)
        {
          gfi_ptr = gi_ptr->functions[f_ix];

          if (gfi_ptr && gfi_ptr->key != gi_ptr)
            gfi_ptr = 0;

          crc32 = crc32_unsigned (crc32, gfi_ptr ? gfi_ptr->cfg_checksum : 0);
          crc32 = crc32_unsigned (crc32,
                                  gfi_ptr ? gfi_ptr->lineno_checksum : 0);
          if (!gfi_ptr)
            continue;

          ci_ptr = gfi_ptr->ctrs;
          for (t_ix = 0; t_ix != GCOV_COUNTERS_SUMMABLE; t_ix++)
            {
              if (!gi_ptr->merge[t_ix])
                continue;

              cs_ptr = &(this_prg->ctrs[t_ix]);
              cs_ptr->num += ci_ptr->num;
              crc32 = crc32_unsigned (crc32, ci_ptr->num);

              for (c_num = 0; c_num < ci_ptr->num; c_num++)
                {
                  cs_ptr->sum_all += ci_ptr->values[c_num];
                  if (cs_ptr->run_max < ci_ptr->values[c_num])
                    cs_ptr->run_max = ci_ptr->values[c_num];
                }
              ci_ptr++;
            }
        }
    }
  gcov_compute_histogram (list, this_prg);
  return crc32;
}

/* Including system dependent components. */
#include "libgcov-driver-system.c"

/* This function merges counters in GI_PTR to an existing gcda file.
   Return 0 on success.
   Return -1 on error. In this case, caller will goto read_fatal.  */

static int
merge_one_data (const char *filename,
		struct gcov_info *gi_ptr,
		struct gcov_summary *prg_p,
		struct gcov_summary *this_prg,
		gcov_position_t *summary_pos_p,
		gcov_position_t *eof_pos_p,
		gcov_unsigned_t crc32)
{
  gcov_unsigned_t tag, length;
  unsigned t_ix;
  int f_ix;
  int error = 0;
  struct gcov_fn_buffer **fn_tail = &fn_buffer;
  struct gcov_summary_buffer **sum_tail = &sum_buffer;

  length = gcov_read_unsigned ();
  if (!gcov_version (gi_ptr, length, filename))
    return -1;

  length = gcov_read_unsigned ();
  if (length != gi_ptr->stamp)
    /* Read from a different compilation. Overwrite the file.  */
    return 0;

  /* Look for program summary.  */
  for (f_ix = 0;;)
    {
      struct gcov_summary tmp;

      *eof_pos_p = gcov_position ();
      tag = gcov_read_unsigned ();
      if (tag != GCOV_TAG_PROGRAM_SUMMARY)
        break;

      f_ix--;
      length = gcov_read_unsigned ();
      gcov_read_summary (&tmp);
      if ((error = gcov_is_error ()))
        goto read_error;
      if (*summary_pos_p)
        {
          /* Save all summaries after the one that will be
             merged into below. These will need to be rewritten
             as histogram merging may change the number of non-zero
             histogram entries that will be emitted, and thus the
             size of the merged summary.  */
          (*sum_tail) = (struct gcov_summary_buffer *)
              xmalloc (sizeof(struct gcov_summary_buffer));
          (*sum_tail)->summary = tmp;
          (*sum_tail)->next = 0;
          sum_tail = &((*sum_tail)->next);
          goto next_summary;
        }
      if (tmp.checksum != crc32)
        goto next_summary;

      for (t_ix = 0; t_ix != GCOV_COUNTERS_SUMMABLE; t_ix++)
        if (tmp.ctrs[t_ix].num != this_prg->ctrs[t_ix].num)
          goto next_summary;
      *prg_p = tmp;
      *summary_pos_p = *eof_pos_p;

    next_summary:;
    }

  /* Merge execution counts for each function.  */
  for (f_ix = 0; (unsigned)f_ix != gi_ptr->n_functions;
       f_ix++, tag = gcov_read_unsigned ())
    {
      const struct gcov_ctr_info *ci_ptr;
      const struct gcov_fn_info *gfi_ptr = gi_ptr->functions[f_ix];

      if (tag != GCOV_TAG_FUNCTION)
        goto read_mismatch;

      length = gcov_read_unsigned ();
      if (!length)
        /* This function did not appear in the other program.
           We have nothing to merge.  */
        continue;

      if (length != GCOV_TAG_FUNCTION_LENGTH)
        goto read_mismatch;

      if (!gfi_ptr || gfi_ptr->key != gi_ptr)
        {
          /* This function appears in the other program.  We
             need to buffer the information in order to write
             it back out -- we'll be inserting data before
             this point, so cannot simply keep the data in the
             file.  */
          fn_tail = buffer_fn_data (filename, gi_ptr, fn_tail, f_ix);
          if (!fn_tail)
            goto read_mismatch;
          continue;
        }

      length = gcov_read_unsigned ();
      if (length != gfi_ptr->ident)
        goto read_mismatch;

      length = gcov_read_unsigned ();
      if (length != gfi_ptr->lineno_checksum)
        goto read_mismatch;

      length = gcov_read_unsigned ();
      if (length != gfi_ptr->cfg_checksum)
        goto read_mismatch;

      ci_ptr = gfi_ptr->ctrs;
      for (t_ix = 0; t_ix < GCOV_COUNTERS; t_ix++)
        {
          gcov_merge_fn merge = gi_ptr->merge[t_ix];

          if (!merge)
            continue;

          tag = gcov_read_unsigned ();
          length = gcov_read_unsigned ();
          if (tag != GCOV_TAG_FOR_COUNTER (t_ix)
              || length != GCOV_TAG_COUNTER_LENGTH (ci_ptr->num))
            goto read_mismatch;
          (*merge) (ci_ptr->values, ci_ptr->num);
          ci_ptr++;
        }
      if ((error = gcov_is_error ()))
        goto read_error;
    }

  if (tag)
    {
    read_mismatch:;
      gcov_error ("profiling:%s:Merge mismatch for %s %u\n",
                  filename, f_ix >= 0 ? "function" : "summary",
                  f_ix < 0 ? -1 - f_ix : f_ix);
      return -1;
    }
  return 0;

read_error:
  gcov_error ("profiling:%s:%s merging\n", filename,
              error < 0 ? "Overflow": "Error");
  return -1;
}

/* Write counters in GI_PTR and the summary in PRG to a gcda file. In
   the case of appending to an existing file, SUMMARY_POS will be non-zero.
   We will write the file starting from SUMMAY_POS.  */

static void
write_one_data (const struct gcov_info *gi_ptr,
		const struct gcov_summary *prg_p,
		const gcov_position_t eof_pos,
		const gcov_position_t summary_pos)
{
  unsigned f_ix;
  struct gcov_summary_buffer *next_sum_buffer;

  /* Write out the data.  */
  if (!eof_pos)
    {
      gcov_write_tag_length (GCOV_DATA_MAGIC, GCOV_VERSION);
      gcov_write_unsigned (gi_ptr->stamp);
    }

  if (summary_pos)
    gcov_seek (summary_pos);

  /* Generate whole program statistics.  */
  gcov_write_summary (GCOV_TAG_PROGRAM_SUMMARY, prg_p);

  /* Rewrite all the summaries that were after the summary we merged
     into. This is necessary as the merged summary may have a different
     size due to the number of non-zero histogram entries changing after
     merging.  */

  while (sum_buffer)
    {
      gcov_write_summary (GCOV_TAG_PROGRAM_SUMMARY, &sum_buffer->summary);
      next_sum_buffer = sum_buffer->next;
      free (sum_buffer);
      sum_buffer = next_sum_buffer;
    }

  /* Write execution counts for each function.  */
  for (f_ix = 0; f_ix != gi_ptr->n_functions; f_ix++)
    {
      unsigned buffered = 0;
      const struct gcov_fn_info *gfi_ptr;
      const struct gcov_ctr_info *ci_ptr;
      gcov_unsigned_t length;
      unsigned t_ix;

      if (fn_buffer && fn_buffer->fn_ix == f_ix)
        {
          /* Buffered data from another program.  */
          buffered = 1;
          gfi_ptr = &fn_buffer->info;
          length = GCOV_TAG_FUNCTION_LENGTH;
        }
      else
        {
          gfi_ptr = gi_ptr->functions[f_ix];
          if (gfi_ptr && gfi_ptr->key == gi_ptr)
            length = GCOV_TAG_FUNCTION_LENGTH;
          else
                length = 0;
        }

      gcov_write_tag_length (GCOV_TAG_FUNCTION, length);
      if (!length)
        continue;

      gcov_write_unsigned (gfi_ptr->ident);
      gcov_write_unsigned (gfi_ptr->lineno_checksum);
      gcov_write_unsigned (gfi_ptr->cfg_checksum);

      ci_ptr = gfi_ptr->ctrs;
      for (t_ix = 0; t_ix < GCOV_COUNTERS; t_ix++)
        {
          gcov_unsigned_t n_counts;
          gcov_type *c_ptr;

          if (!gi_ptr->merge[t_ix])
            continue;

          n_counts = ci_ptr->num;
          gcov_write_tag_length (GCOV_TAG_FOR_COUNTER (t_ix),
                                 GCOV_TAG_COUNTER_LENGTH (n_counts));
          c_ptr = ci_ptr->values;
          while (n_counts--)
            gcov_write_counter (*c_ptr++);
          ci_ptr++;
        }
      if (buffered)
        fn_buffer = free_fn_data (gi_ptr, fn_buffer, GCOV_COUNTERS);
    }

  gcov_write_unsigned (0);
}

/* Helper function for merging summary.
   Return -1 on error. Return 0 on success.  */

static int
merge_summary (const char *filename, int run_counted,
	       const struct gcov_info *gi_ptr, struct gcov_summary *prg,
	       struct gcov_summary *this_prg, gcov_unsigned_t crc32,
	       struct gcov_summary *all_prg __attribute__ ((unused)))
{
  struct gcov_ctr_summary *cs_prg, *cs_tprg;
  unsigned t_ix;
#if !GCOV_LOCKED 
  /* summary for all instances of program.  */ 
  struct gcov_ctr_summary *cs_all;
#endif 

  /* Merge the summaries.  */
  for (t_ix = 0; t_ix < GCOV_COUNTERS_SUMMABLE; t_ix++)
    {
      cs_prg = &(prg->ctrs[t_ix]);
      cs_tprg = &(this_prg->ctrs[t_ix]);

      if (gi_ptr->merge[t_ix])
        {
	  int first = !cs_prg->runs;

	  if (!run_counted)
	    cs_prg->runs++;
          if (first)
            cs_prg->num = cs_tprg->num;
          cs_prg->sum_all += cs_tprg->sum_all;
          if (cs_prg->run_max < cs_tprg->run_max)
            cs_prg->run_max = cs_tprg->run_max;
          cs_prg->sum_max += cs_tprg->run_max;
          if (first)
            memcpy (cs_prg->histogram, cs_tprg->histogram,
                   sizeof (gcov_bucket_type) * GCOV_HISTOGRAM_SIZE);
          else
            gcov_histogram_merge (cs_prg->histogram, cs_tprg->histogram);
        }
      else if (cs_prg->runs)
        {
          gcov_error ("profiling:%s:Merge mismatch for summary.\n",
                      filename);
          return -1;
        }
#if !GCOV_LOCKED
      cs_all = &all_prg->ctrs[t_ix];
      if (!cs_all->runs && cs_prg->runs)
        {
          cs_all->num = cs_prg->num;
          cs_all->runs = cs_prg->runs;
          cs_all->sum_all = cs_prg->sum_all;
          cs_all->run_max = cs_prg->run_max;
          cs_all->sum_max = cs_prg->sum_max;
        }
      else if (!all_prg->checksum
               /* Don't compare the histograms, which may have slight
                  variations depending on the order they were updated
                  due to the truncating integer divides used in the
                  merge.  */
               && (cs_all->num != cs_prg->num
                   || cs_all->runs != cs_prg->runs
                   || cs_all->sum_all != cs_prg->sum_all
                   || cs_all->run_max != cs_prg->run_max
                   || cs_all->sum_max != cs_prg->sum_max))
             {
               gcov_error ("profiling:%s:Data file mismatch - some "
                           "data files may have been concurrently "
                           "updated without locking support\n", filename);
               all_prg->checksum = ~0u;
             }
#endif
    }
  
  prg->checksum = crc32;

  return 0;
}


/* Sort N entries in VALUE_ARRAY in descending order.
   Each entry in VALUE_ARRAY has two values. The sorting
   is based on the second value.  */

GCOV_LINKAGE  void
gcov_sort_n_vals (gcov_type *value_array, int n)
{
  int j, k;

  for (j = 2; j < n; j += 2)
    {
      gcov_type cur_ent[2];

      cur_ent[0] = value_array[j];
      cur_ent[1] = value_array[j + 1];
      k = j - 2;
      while (k >= 0 && value_array[k + 1] < cur_ent[1])
        {
          value_array[k + 2] = value_array[k];
          value_array[k + 3] = value_array[k+1];
          k -= 2;
        }
      value_array[k + 2] = cur_ent[0];
      value_array[k + 3] = cur_ent[1];
    }
}

/* Sort the profile counters for all indirect call sites. Counters
   for each call site are allocated in array COUNTERS.  */

static void
gcov_sort_icall_topn_counter (const struct gcov_ctr_info *counters)
{
  int i;
  gcov_type *values;
  int n = counters->num;

  gcc_assert (!(n % GCOV_ICALL_TOPN_NCOUNTS));
  values = counters->values;

  for (i = 0; i < n; i += GCOV_ICALL_TOPN_NCOUNTS)
    {
      gcov_type *value_array = &values[i + 1];
      gcov_sort_n_vals (value_array, GCOV_ICALL_TOPN_NCOUNTS - 1);
    }
}

/* Sort topn indirect_call profile counters in GI_PTR.  */

static void
gcov_sort_topn_counter_arrays (const struct gcov_info *gi_ptr)
{
  unsigned int i;
  int f_ix;
  const struct gcov_fn_info *gfi_ptr;
  const struct gcov_ctr_info *ci_ptr;

  if (!gi_ptr->merge[GCOV_COUNTER_ICALL_TOPNV]) 
    return;

  for (f_ix = 0; (unsigned)f_ix != gi_ptr->n_functions; f_ix++)
    {
      gfi_ptr = gi_ptr->functions[f_ix];
      ci_ptr = gfi_ptr->ctrs;
      for (i = 0; i < GCOV_COUNTERS; i++)
        {
          if (!gi_ptr->merge[i])
            continue;
          if (i == GCOV_COUNTER_ICALL_TOPNV)
            {
              gcov_sort_icall_topn_counter (ci_ptr);
              break;
            }
          ci_ptr++;
        }
    }
}

/* Dump the coverage counts for one gcov_info object. We merge with existing
   counts when possible, to avoid growing the .da files ad infinitum. We use
   this program's checksum to make sure we only accumulate whole program
   statistics to the correct summary. An object file might be embedded
   in two separate programs, and we must keep the two program
   summaries separate.  */

static void
dump_one_gcov (struct gcov_info *gi_ptr, struct gcov_filename *gf,
	       unsigned run_counted,
	       gcov_unsigned_t crc32, struct gcov_summary *all_prg,
	       struct gcov_summary *this_prg)
{
  struct gcov_summary prg; /* summary for this object over all program.  */
  int error;
  gcov_unsigned_t tag;
  gcov_position_t summary_pos = 0;
  gcov_position_t eof_pos = 0;

  fn_buffer = 0;
  sum_buffer = 0;

  gcov_sort_topn_counter_arrays (gi_ptr);

  error = gcov_exit_open_gcda_file (gi_ptr, gf);
  if (error == -1)
    return;

  tag = gcov_read_unsigned ();
  if (tag)
    {
      /* Merge data from file.  */
      if (tag != GCOV_DATA_MAGIC)
        {
          gcov_error ("profiling:%s:Not a gcov data file\n", gf->filename);
          goto read_fatal;
        }
      error = merge_one_data (gf->filename, gi_ptr, &prg, this_prg,
			      &summary_pos, &eof_pos, crc32);
      if (error == -1)
        goto read_fatal;
    }

  gcov_rewrite ();

  if (!summary_pos)
    {
      memset (&prg, 0, sizeof (prg));
      summary_pos = eof_pos;
    }

  error = merge_summary (gf->filename, run_counted, gi_ptr, &prg, this_prg,
			 crc32, all_prg);
  if (error == -1)
    goto read_fatal;

  write_one_data (gi_ptr, &prg, eof_pos, summary_pos);
  /* fall through */

read_fatal:;
  while (fn_buffer)
    fn_buffer = free_fn_data (gi_ptr, fn_buffer, GCOV_COUNTERS);

  if ((error = gcov_close ()))
    gcov_error (error  < 0 ?
                "profiling:%s:Overflow writing\n" :
                "profiling:%s:Error writing\n",
                gf->filename);
}


/* Dump all the coverage counts for the program. It first computes program
   summary and then traverses gcov_list list and dumps the gcov_info
   objects one by one.  */

#if !IN_GCOV_TOOL
static
#endif
void
gcov_do_dump (struct gcov_info *list, int run_counted)
{
  struct gcov_info *gi_ptr;
  struct gcov_filename gf;
  gcov_unsigned_t crc32;
  struct gcov_summary all_prg;
  struct gcov_summary this_prg;

  crc32 = compute_summary (list, &this_prg, &gf.max_length);

  allocate_filename_struct (&gf);
#if !GCOV_LOCKED
  memset (&all_prg, 0, sizeof (all_prg));
#endif

  /* Now merge each file.  */
  for (gi_ptr = list; gi_ptr; gi_ptr = gi_ptr->next)
    dump_one_gcov (gi_ptr, &gf, run_counted, crc32, &all_prg, &this_prg);

  free (gf.filename);
}

#if !IN_GCOV_TOOL
void
__gcov_dump_one (struct gcov_root *root)
{
  if (root->dumped)
    return;

  gcov_do_dump (root->list, root->run_counted);
  
  root->dumped = 1;
  root->run_counted = 1;
}

/* Per-dynamic-object gcov state.  */
struct gcov_root __gcov_root;

/* Exactly one of these will be live in the process image.  */
struct gcov_master __gcov_master = 
  {GCOV_VERSION, 0};

static void
gcov_exit (void)
{
  __gcov_dump_one (&__gcov_root);
  if (__gcov_root.next)
    __gcov_root.next->prev = __gcov_root.prev;
  if (__gcov_root.prev)
    __gcov_root.prev->next = __gcov_root.next;
  else
    __gcov_master.root = __gcov_root.next;
}

/* Add a new object file onto the bb chain.  Invoked automatically
  when running an object file's global ctors.  */

void
__gcov_init (struct gcov_info *info)
{
  if (!info->version || !info->n_functions)
    return;
  if (gcov_version (info, info->version, 0))
    {
      if (!__gcov_root.list)
	{
	  /* Add to master list and at exit function.  */
	  if (gcov_version (NULL, __gcov_master.version, "<master>"))
	    {
	      __gcov_root.next = __gcov_master.root;
	      if (__gcov_master.root)
		__gcov_master.root->prev = &__gcov_root;
	      __gcov_master.root = &__gcov_root;
	    }
	  atexit (gcov_exit);
	}

      info->next = __gcov_root.list;
      __gcov_root.list = info;
    }
}
#endif /* !IN_GCOV_TOOL */
#endif /* L_gcov */
#endif /* inhibit_libc */