/* Gcov.c: prepend line execution counts and branch probabilities to a
   source file.
   Copyright (C) 1990, 1991, 1992, 1993, 1994, 1996, 1997, 1998, 1999,
   2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
   Free Software Foundation, Inc.
   Contributed by James E. Wilson of Cygnus Support.
   Mangled by Bob Manson of Cygnus Support.
   Mangled further by Nathan Sidwell <nathan@codesourcery.com>

Gcov 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.

Gcov 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.

You should have received a copy of the GNU General Public License
along with Gcov; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */

/* ??? Print a list of the ten blocks with the highest execution counts,
   and list the line numbers corresponding to those blocks.  Also, perhaps
   list the line numbers with the highest execution counts, only printing
   the first if there are several which are all listed in the same block.  */

/* ??? Should have an option to print the number of basic blocks, and the
   percent of them that are covered.  */

/* Need an option to show individual block counts, and show
   probabilities of fall through arcs.  */

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "intl.h"
#include "version.h"

#include <getopt.h>

#define IN_GCOV 1
#include "gcov-io.h"
#include "gcov-io.c"

/* The gcno file is generated by -ftest-coverage option. The gcda file is
   generated by a program compiled with -fprofile-arcs. Their formats
   are documented in gcov-io.h.  */

/* The functions in this file for creating and solution program flow graphs
   are very similar to functions in the gcc source file profile.c.  In
   some places we make use of the knowledge of how profile.c works to
   select particular algorithms here.  */

/* This is the size of the buffer used to read in source file lines.  */

#define STRING_SIZE 200

struct function_info;
struct block_info;
struct source_info;

/* Describes an arc between two basic blocks.  */

typedef struct arc_info
{
  /* source and destination blocks.  */
  struct block_info *src;
  struct block_info *dst;

  /* transition counts.  */
  gcov_type count;
  /* used in cycle search, so that we do not clobber original counts.  */
  gcov_type cs_count;

  unsigned int count_valid : 1;
  unsigned int on_tree : 1;
  unsigned int fake : 1;
  unsigned int fall_through : 1;

  /* Arc is for a function that abnormally returns.  */
  unsigned int is_call_non_return : 1;

  /* Arc is for catch/setjmp.  */
  unsigned int is_nonlocal_return : 1;

  /* Is an unconditional branch.  */
  unsigned int is_unconditional : 1;

  /* Loop making arc.  */
  unsigned int cycle : 1;

  /* Next branch on line.  */
  struct arc_info *line_next;

  /* Links to next arc on src and dst lists.  */
  struct arc_info *succ_next;
  struct arc_info *pred_next;
} arc_t;

/* Describes a basic block. Contains lists of arcs to successor and
   predecessor blocks.  */

typedef struct block_info
{
  /* Chain of exit and entry arcs.  */
  arc_t *succ;
  arc_t *pred;

  /* Number of unprocessed exit and entry arcs.  */
  gcov_type num_succ;
  gcov_type num_pred;

  /* Block execution count.  */
  gcov_type count;
  unsigned flags : 13;
  unsigned count_valid : 1;
  unsigned valid_chain : 1;
  unsigned invalid_chain : 1;

  /* Block is a call instrumenting site.  */
  unsigned is_call_site : 1; /* Does the call.  */
  unsigned is_call_return : 1; /* Is the return.  */

  /* Block is a landing pad for longjmp or throw.  */
  unsigned is_nonlocal_return : 1;

  union
  {
    struct
    {
     /* Array of line numbers and source files. source files are
        introduced by a linenumber of zero, the next 'line number' is
        the number of the source file.  Always starts with a source
        file.  */
      unsigned *encoding;
      unsigned num;
    } line; /* Valid until blocks are linked onto lines */
    struct
    {
      /* Single line graph cycle workspace.  Used for all-blocks
	 mode.  */
      arc_t *arc;
      unsigned ident;
    } cycle; /* Used in all-blocks mode, after blocks are linked onto
	       lines.  */
  } u;

  /* Temporary chain for solving graph, and for chaining blocks on one
     line.  */
  struct block_info *chain;

} block_t;

/* Describes a single function. Contains an array of basic blocks.  */

typedef struct function_info
{
  /* Name of function.  */
  char *name;
  unsigned ident;
  unsigned checksum;

  /* Array of basic blocks.  */
  block_t *blocks;
  unsigned num_blocks;
  unsigned blocks_executed;

  /* Raw arc coverage counts.  */
  gcov_type *counts;
  unsigned num_counts;

  /* First line number.  */
  unsigned line;
  struct source_info *src;

  /* Next function in same source file.  */
  struct function_info *line_next;

  /* Next function.  */
  struct function_info *next;
} function_t;

/* Describes coverage of a file or function.  */

typedef struct coverage_info
{
  int lines;
  int lines_executed;

  int branches;
  int branches_executed;
  int branches_taken;

  int calls;
  int calls_executed;

  char *name;
} coverage_t;

/* Describes a single line of source. Contains a chain of basic blocks
   with code on it.  */

typedef struct line_info
{
  gcov_type count;	   /* execution count */
  union
  {
    arc_t *branches;	   /* branches from blocks that end on this
			      line. Used for branch-counts when not
			      all-blocks mode.  */
    block_t *blocks;       /* blocks which start on this line.  Used
			      in all-blocks mode.  */
  } u;
  unsigned exists : 1;
} line_t;

/* Describes a file mentioned in the block graph.  Contains an array
   of line info.  */

typedef struct source_info
{
  /* Name of source file.  */
  char *name;
  unsigned index;
  time_t file_time;

  /* Array of line information.  */
  line_t *lines;
  unsigned num_lines;

  coverage_t coverage;

  /* Functions in this source file.  These are in ascending line
     number order.  */
  function_t *functions;

  /* Next source file.  */
  struct source_info *next;
} source_t;

/* Holds a list of function basic block graphs.  */

static function_t *functions;

/* This points to the head of the sourcefile structure list.  New elements
   are always prepended.  */

static source_t *sources;

/* Next index for a source file.  */

static unsigned source_index;

/* This holds data summary information.  */

static struct gcov_summary object_summary;
static unsigned program_count;

/* Modification time of graph file.  */

static time_t bbg_file_time;

/* Name and file pointer of the input file for the basic block graph.  */

static char *bbg_file_name;

/* Stamp of the bbg file */
static unsigned bbg_stamp;

/* Name and file pointer of the input file for the arc count data.  */

static char *da_file_name;

/* Data file is missing.  */

static int no_data_file;

/* If there is several input files, compute and display results after
   reading all data files.  This way if two or more gcda file refer to
   the same source file (eg inline subprograms in a .h file), the
   counts are added.  */

static int multiple_files = 0;

/* Output branch probabilities.  */

static int flag_branches = 0;

/* Show unconditional branches too.  */
static int flag_unconditional = 0;

/* Output a gcov file if this is true.  This is on by default, and can
   be turned off by the -n option.  */

static int flag_gcov_file = 1;

/* For included files, make the gcov output file name include the name
   of the input source file.  For example, if x.h is included in a.c,
   then the output file name is a.c##x.h.gcov instead of x.h.gcov.  */

static int flag_long_names = 0;

/* Output count information for every basic block, not merely those
   that contain line number information.  */

static int flag_all_blocks = 0;

/* Output summary info for each function.  */

static int flag_function_summary = 0;

/* Object directory file prefix.  This is the directory/file where the
   graph and data files are looked for, if nonzero.  */

static char *object_directory = 0;

/* Preserve all pathname components. Needed when object files and
   source files are in subdirectories. '/' is mangled as '#', '.' is
   elided and '..' mangled to '^'.  */

static int flag_preserve_paths = 0;

/* Output the number of times a branch was taken as opposed to the percentage
   of times it was taken.  */

static int flag_counts = 0;

/* Forward declarations.  */
static void fnotice (FILE *, const char *, ...) ATTRIBUTE_PRINTF_2;
static int process_args (int, char **);
static void print_usage (int) ATTRIBUTE_NORETURN;
static void print_version (void) ATTRIBUTE_NORETURN;
static void process_file (const char *);
static void generate_results (const char *);
static void create_file_names (const char *);
static source_t *find_source (const char *);
static int read_graph_file (void);
static int read_count_file (void);
static void solve_flow_graph (function_t *);
static void add_branch_counts (coverage_t *, const arc_t *);
static void add_line_counts (coverage_t *, function_t *);
static void function_summary (const coverage_t *, const char *);
static const char *format_gcov (gcov_type, gcov_type, int);
static void accumulate_line_counts (source_t *);
static int output_branch_count (FILE *, int, const arc_t *);
static void output_lines (FILE *, const source_t *);
static char *make_gcov_file_name (const char *, const char *);
static void release_structures (void);
extern int main (int, char **);

int
main (int argc, char **argv)
{
  int argno;

  /* Unlock the stdio streams.  */
  unlock_std_streams ();

  gcc_init_libintl ();

  /* Handle response files.  */
  expandargv (&argc, &argv);

  argno = process_args (argc, argv);
  if (optind == argc)
    print_usage (true);

  if (argc - argno > 1)
    multiple_files = 1;

  for (; argno != argc; argno++)
    process_file (argv[argno]);

  generate_results (multiple_files ? NULL : argv[argc - 1]);

  release_structures ();

  return 0;
}

static void
fnotice (FILE *file, const char *cmsgid, ...)
{
  va_list ap;

  va_start (ap, cmsgid);
  vfprintf (file, _(cmsgid), ap);
  va_end (ap);
}

/* Print a usage message and exit.  If ERROR_P is nonzero, this is an error,
   otherwise the output of --help.  */

static void
print_usage (int error_p)
{
  FILE *file = error_p ? stderr : stdout;
  int status = error_p ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE;

  fnotice (file, "Usage: gcov [OPTION]... SOURCEFILE...\n\n");
  fnotice (file, "Print code coverage information.\n\n");
  fnotice (file, "  -h, --help                      Print this help, then exit\n");
  fnotice (file, "  -v, --version                   Print version number, then exit\n");
  fnotice (file, "  -a, --all-blocks                Show information for every basic block\n");
  fnotice (file, "  -b, --branch-probabilities      Include branch probabilities in output\n");
  fnotice (file, "  -c, --branch-counts             Given counts of branches taken\n\
                                    rather than percentages\n");
  fnotice (file, "  -n, --no-output                 Do not create an output file\n");
  fnotice (file, "  -l, --long-file-names           Use long output file names for included\n\
                                    source files\n");
  fnotice (file, "  -f, --function-summaries        Output summaries for each function\n");
  fnotice (file, "  -o, --object-directory DIR|FILE Search for object files in DIR or called FILE\n");
  fnotice (file, "  -p, --preserve-paths            Preserve all pathname components\n");
  fnotice (file, "  -u, --unconditional-branches    Show unconditional branch counts too\n");
  fnotice (file, "\nFor bug reporting instructions, please see:\n%s.\n",
	   bug_report_url);
  exit (status);
}

/* Print version information and exit.  */

static void
print_version (void)
{
  fnotice (stdout, "gcov %s%s\n", pkgversion_string, version_string);
  fprintf (stdout, "Copyright %s 2009 Free Software Foundation, Inc.\n",
	   _("(C)"));
  fnotice (stdout,
	   _("This is free software; see the source for copying conditions.\n"
	     "There is NO warranty; not even for MERCHANTABILITY or \n"
	     "FITNESS FOR A PARTICULAR PURPOSE.\n\n"));
  exit (SUCCESS_EXIT_CODE);
}

static const struct option options[] =
{
  { "help",                 no_argument,       NULL, 'h' },
  { "version",              no_argument,       NULL, 'v' },
  { "all-blocks",           no_argument,       NULL, 'a' },
  { "branch-probabilities", no_argument,       NULL, 'b' },
  { "branch-counts",        no_argument,       NULL, 'c' },
  { "no-output",            no_argument,       NULL, 'n' },
  { "long-file-names",      no_argument,       NULL, 'l' },
  { "function-summaries",   no_argument,       NULL, 'f' },
  { "preserve-paths",       no_argument,       NULL, 'p' },
  { "object-directory",     required_argument, NULL, 'o' },
  { "object-file",          required_argument, NULL, 'o' },
  { "unconditional-branches", no_argument,     NULL, 'u' },
  { 0, 0, 0, 0 }
};

/* Process args, return index to first non-arg.  */

static int
process_args (int argc, char **argv)
{
  int opt;

  while ((opt = getopt_long (argc, argv, "abcfhlno:puv", options, NULL)) != -1)
    {
      switch (opt)
	{
	case 'a':
	  flag_all_blocks = 1;
	  break;
	case 'b':
	  flag_branches = 1;
	  break;
	case 'c':
	  flag_counts = 1;
	  break;
	case 'f':
	  flag_function_summary = 1;
	  break;
	case 'h':
	  print_usage (false);
	  /* print_usage will exit.  */
	case 'l':
	  flag_long_names = 1;
	  break;
	case 'n':
	  flag_gcov_file = 0;
	  break;
	case 'o':
	  object_directory = optarg;
	  break;
	case 'p':
	  flag_preserve_paths = 1;
	  break;
	case 'u':
	  flag_unconditional = 1;
	  break;
	case 'v':
	  print_version ();
	  /* print_version will exit.  */
	default:
	  print_usage (true);
	  /* print_usage will exit.  */
	}
    }

  return optind;
}

/* Process a single source file.  */

static void
process_file (const char *file_name)
{
  function_t *fn;
  function_t *fn_p;
  function_t *old_functions;

  /* Save and clear the list of current functions.  They will be appended
     later.  */
  old_functions = functions;
  functions = NULL;

  create_file_names (file_name);
  if (read_graph_file ())
    return;

  if (!functions)
    {
      fnotice (stderr, "%s:no functions found\n", bbg_file_name);
      return;
    }

  if (read_count_file ())
    return;

  for (fn_p = NULL, fn = functions; fn; fn_p = fn, fn = fn->next)
    solve_flow_graph (fn);

  if (fn_p)
    fn_p->next = old_functions;
}

static void
generate_results (const char *file_name)
{
  source_t *src;
  function_t *fn;

  for (src = sources; src; src = src->next)
    src->lines = XCNEWVEC (line_t, src->num_lines);
  for (fn = functions; fn; fn = fn->next)
    {
      coverage_t coverage;

      memset (&coverage, 0, sizeof (coverage));
      coverage.name = fn->name;
      add_line_counts (flag_function_summary ? &coverage : NULL, fn);
      if (flag_function_summary)
	{
	  function_summary (&coverage, "Function");
	  fnotice (stdout, "\n");
	}
    }

  for (src = sources; src; src = src->next)
    {
      accumulate_line_counts (src);
      function_summary (&src->coverage, "File");
      if (flag_gcov_file)
	{
	  char *gcov_file_name = make_gcov_file_name (file_name, src->name);
	  FILE *gcov_file = fopen (gcov_file_name, "w");

	  if (gcov_file)
	    {
	      fnotice (stdout, "%s:creating '%s'\n",
		       src->name, gcov_file_name);
	      output_lines (gcov_file, src);
	      if (ferror (gcov_file))
		    fnotice (stderr, "%s:error writing output file '%s'\n",
			     src->name, gcov_file_name);
	      fclose (gcov_file);
	    }
	  else
	    fnotice (stderr, "%s:could not open output file '%s'\n",
		     src->name, gcov_file_name);
	  free (gcov_file_name);
	}
      fnotice (stdout, "\n");
    }
}

/* Release all memory used.  */

static void
release_structures (void)
{
  function_t *fn;
  source_t *src;

  while ((src = sources))
    {
      sources = src->next;

      free (src->name);
      free (src->lines);
    }

  while ((fn = functions))
    {
      unsigned ix;
      block_t *block;

      functions = fn->next;
      for (ix = fn->num_blocks, block = fn->blocks; ix--; block++)
	{
	  arc_t *arc, *arc_n;

	  for (arc = block->succ; arc; arc = arc_n)
	    {
	      arc_n = arc->succ_next;
	      free (arc);
	    }
	}
      free (fn->blocks);
      free (fn->counts);
    }
}

/* Generate the names of the graph and data files. If OBJECT_DIRECTORY
   is not specified, these are looked for in the current directory,
   and named from the basename of the FILE_NAME sans extension. If
   OBJECT_DIRECTORY is specified and is a directory, the files are in
   that directory, but named from the basename of the FILE_NAME, sans
   extension. Otherwise OBJECT_DIRECTORY is taken to be the name of
   the object *file*, and the data files are named from that.  */

static void
create_file_names (const char *file_name)
{
  char *cptr;
  char *name;
  int length = strlen (file_name);
  int base;

  /* Free previous file names.  */
  if (bbg_file_name)
    free (bbg_file_name);
  if (da_file_name)
    free (da_file_name);
  da_file_name = bbg_file_name = NULL;
  bbg_file_time = 0;
  bbg_stamp = 0;

  if (object_directory && object_directory[0])
    {
      struct stat status;

      length += strlen (object_directory) + 2;
      name = XNEWVEC (char, length);
      name[0] = 0;

      base = !stat (object_directory, &status) && S_ISDIR (status.st_mode);
      strcat (name, object_directory);
      if (base && (! IS_DIR_SEPARATOR (name[strlen (name) - 1])))
	strcat (name, "/");
    }
  else
    {
      name = XNEWVEC (char, length + 1);
      name[0] = 0;
      base = 1;
    }

  if (base)
    {
      /* Append source file name.  */
      const char *cptr = lbasename (file_name);
      strcat (name, cptr ? cptr : file_name);
    }

  /* Remove the extension.  */
  cptr = strrchr (name, '.');
  if (cptr)
    *cptr = 0;

  length = strlen (name);
  
  bbg_file_name = XNEWVEC (char, length + strlen (GCOV_NOTE_SUFFIX) + 1);
  strcpy (bbg_file_name, name);
  strcpy (bbg_file_name + length, GCOV_NOTE_SUFFIX);

  da_file_name = XNEWVEC (char, length + strlen (GCOV_DATA_SUFFIX) + 1);
  strcpy (da_file_name, name);
  strcpy (da_file_name + length, GCOV_DATA_SUFFIX);

  free (name);
  return;
}

/* Find or create a source file structure for FILE_NAME. Copies
   FILE_NAME on creation */

static source_t *
find_source (const char *file_name)
{
  source_t *src;
  struct stat status;

  if (!file_name)
    file_name = "<unknown>";

  for (src = sources; src; src = src->next)
    if (!strcmp (file_name, src->name))
      break;

  if (!src)
    {
      src = XCNEW (source_t);
      src->name = xstrdup (file_name);
      src->coverage.name = src->name;
      src->index = source_index++;
      src->next = sources;
      sources = src;
      
      if (!stat (file_name, &status))
	src->file_time = status.st_mtime;
    }

  if (src->file_time > bbg_file_time)
    {
      static int info_emitted;

      fnotice (stderr, "%s:source file is newer than graph file '%s'\n",
	       src->name, bbg_file_name);
      if (!info_emitted)
	{
	  fnotice (stderr,
		   "(the message is only displayed one per source file)\n");
	  info_emitted = 1;
	}
      src->file_time = 0;
    }

  return src;
}

/* Read the graph file. Return nonzero on fatal error.  */

static int
read_graph_file (void)
{
  unsigned version;
  unsigned current_tag = 0;
  struct function_info *fn = NULL;
  function_t *old_functions_head = functions;
  source_t *src = NULL;
  unsigned ix;
  unsigned tag;

  if (!gcov_open (bbg_file_name, 1))
    {
      fnotice (stderr, "%s:cannot open graph file\n", bbg_file_name);
      return 1;
    }
  bbg_file_time = gcov_time ();
  if (!gcov_magic (gcov_read_unsigned (), GCOV_NOTE_MAGIC))
    {
      fnotice (stderr, "%s:not a gcov graph file\n", bbg_file_name);
      gcov_close ();
      return 1;
    }

  version = gcov_read_unsigned ();
  if (version != GCOV_VERSION)
    {
      char v[4], e[4];

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

      fnotice (stderr, "%s:version '%.4s', prefer '%.4s'\n",
	       bbg_file_name, v, e);
    }
  bbg_stamp = gcov_read_unsigned ();

  while ((tag = gcov_read_unsigned ()))
    {
      unsigned length = gcov_read_unsigned ();
      gcov_position_t base = gcov_position ();

      if (tag == GCOV_TAG_FUNCTION)
	{
	  char *function_name;
	  unsigned ident, checksum, lineno;
	  source_t *src;
	  function_t *probe, *prev;

	  ident = gcov_read_unsigned ();
	  checksum = gcov_read_unsigned ();
	  function_name = xstrdup (gcov_read_string ());
	  src = find_source (gcov_read_string ());
	  lineno = gcov_read_unsigned ();

	  fn = XCNEW (function_t);
	  fn->name = function_name;
	  fn->ident = ident;
	  fn->checksum = checksum;
	  fn->src = src;
	  fn->line = lineno;

	  fn->next = functions;
	  functions = fn;
	  current_tag = tag;

	  if (lineno >= src->num_lines)
	    src->num_lines = lineno + 1;
	  /* Now insert it into the source file's list of
	     functions. Normally functions will be encountered in
	     ascending order, so a simple scan is quick.  */
	  for (probe = src->functions, prev = NULL;
	       probe && probe->line > lineno;
	       prev = probe, probe = probe->line_next)
	    continue;
	  fn->line_next = probe;
	  if (prev)
	    prev->line_next = fn;
	  else
	    src->functions = fn;
	}
      else if (fn && tag == GCOV_TAG_BLOCKS)
	{
	  if (fn->blocks)
	    fnotice (stderr, "%s:already seen blocks for '%s'\n",
		     bbg_file_name, fn->name);
	  else
	    {
	      unsigned ix, num_blocks = GCOV_TAG_BLOCKS_NUM (length);
	      fn->num_blocks = num_blocks;

	      fn->blocks = XCNEWVEC (block_t, fn->num_blocks);
	      for (ix = 0; ix != num_blocks; ix++)
		fn->blocks[ix].flags = gcov_read_unsigned ();
	    }
	}
      else if (fn && tag == GCOV_TAG_ARCS)
	{
	  unsigned src = gcov_read_unsigned ();
	  unsigned num_dests = GCOV_TAG_ARCS_NUM (length);

	  if (src >= fn->num_blocks || fn->blocks[src].succ)
	    goto corrupt;

	  while (num_dests--)
	    {
	      struct arc_info *arc;
	      unsigned dest = gcov_read_unsigned ();
	      unsigned flags = gcov_read_unsigned ();

	      if (dest >= fn->num_blocks)
		goto corrupt;
	      arc = XCNEW (arc_t);

	      arc->dst = &fn->blocks[dest];
	      arc->src = &fn->blocks[src];

	      arc->count = 0;
	      arc->count_valid = 0;
	      arc->on_tree = !!(flags & GCOV_ARC_ON_TREE);
	      arc->fake = !!(flags & GCOV_ARC_FAKE);
	      arc->fall_through = !!(flags & GCOV_ARC_FALLTHROUGH);

	      arc->succ_next = fn->blocks[src].succ;
	      fn->blocks[src].succ = arc;
	      fn->blocks[src].num_succ++;

	      arc->pred_next = fn->blocks[dest].pred;
	      fn->blocks[dest].pred = arc;
	      fn->blocks[dest].num_pred++;

	      if (arc->fake)
		{
		  if (src)
		    {
		      /* Exceptional exit from this function, the
			 source block must be a call.  */
		      fn->blocks[src].is_call_site = 1;
		      arc->is_call_non_return = 1;
		    }
		  else
		    {
		      /* Non-local return from a callee of this
		         function. The destination block is a catch or
		         setjmp.  */
		      arc->is_nonlocal_return = 1;
		      fn->blocks[dest].is_nonlocal_return = 1;
		    }
		}

	      if (!arc->on_tree)
		fn->num_counts++;
	    }
	}
      else if (fn && tag == GCOV_TAG_LINES)
	{
	  unsigned blockno = gcov_read_unsigned ();
	  unsigned *line_nos = XCNEWVEC (unsigned, length - 1);

	  if (blockno >= fn->num_blocks || fn->blocks[blockno].u.line.encoding)
	    goto corrupt;

	  for (ix = 0; ;  )
	    {
	      unsigned lineno = gcov_read_unsigned ();

	      if (lineno)
		{
		  if (!ix)
		    {
		      line_nos[ix++] = 0;
		      line_nos[ix++] = src->index;
		    }
		  line_nos[ix++] = lineno;
		  if (lineno >= src->num_lines)
		    src->num_lines = lineno + 1;
		}
	      else
		{
		  const char *file_name = gcov_read_string ();

		  if (!file_name)
		    break;
		  src = find_source (file_name);

		  line_nos[ix++] = 0;
		  line_nos[ix++] = src->index;
		}
	    }

	  fn->blocks[blockno].u.line.encoding = line_nos;
	  fn->blocks[blockno].u.line.num = ix;
	}
      else if (current_tag && !GCOV_TAG_IS_SUBTAG (current_tag, tag))
	{
	  fn = NULL;
	  current_tag = 0;
	}
      gcov_sync (base, length);
      if (gcov_is_error ())
	{
	corrupt:;
	  fnotice (stderr, "%s:corrupted\n", bbg_file_name);
	  gcov_close ();
	  return 1;
	}
    }
  gcov_close ();

  /* We built everything backwards, so nreverse them all.  */

  /* Reverse sources. Not strictly necessary, but we'll then process
     them in the 'expected' order.  */
  {
    source_t *src, *src_p, *src_n;

    for (src_p = NULL, src = sources; src; src_p = src, src = src_n)
      {
	src_n = src->next;
	src->next = src_p;
      }
    sources =  src_p;
  }

  /* Reverse functions.  */
  {
    function_t *fn, *fn_p, *fn_n;

    for (fn_p = old_functions_head, fn = functions;
	 fn != old_functions_head;
	 fn_p = fn, fn = fn_n)
      {
	unsigned ix;

	fn_n = fn->next;
	fn->next = fn_p;

	/* Reverse the arcs.  */
	for (ix = fn->num_blocks; ix--;)
	  {
	    arc_t *arc, *arc_p, *arc_n;

	    for (arc_p = NULL, arc = fn->blocks[ix].succ; arc;
		 arc_p = arc, arc = arc_n)
	      {
		arc_n = arc->succ_next;
		arc->succ_next = arc_p;
	      }
	    fn->blocks[ix].succ = arc_p;

	    for (arc_p = NULL, arc = fn->blocks[ix].pred; arc;
		 arc_p = arc, arc = arc_n)
	      {
		arc_n = arc->pred_next;
		arc->pred_next = arc_p;
	      }
	    fn->blocks[ix].pred = arc_p;
	  }
      }
    functions = fn_p;
  }
  return 0;
}

/* Reads profiles from the count file and attach to each
   function. Return nonzero if fatal error.  */

static int
read_count_file (void)
{
  unsigned ix;
  unsigned version;
  unsigned tag;
  function_t *fn = NULL;
  int error = 0;

  if (!gcov_open (da_file_name, 1))
    {
      fnotice (stderr, "%s:cannot open data file, assuming not executed\n",
	       da_file_name);
      no_data_file = 1;
      return 0;
    }
  if (!gcov_magic (gcov_read_unsigned (), GCOV_DATA_MAGIC))
    {
      fnotice (stderr, "%s:not a gcov data file\n", da_file_name);
    cleanup:;
      gcov_close ();
      return 1;
    }
  version = gcov_read_unsigned ();
  if (version != GCOV_VERSION)
    {
      char v[4], e[4];

      GCOV_UNSIGNED2STRING (v, version);
      GCOV_UNSIGNED2STRING (e, GCOV_VERSION);
      
      fnotice (stderr, "%s:version '%.4s', prefer version '%.4s'\n",
	       da_file_name, v, e);
    }
  tag = gcov_read_unsigned ();
  if (tag != bbg_stamp)
    {
      fnotice (stderr, "%s:stamp mismatch with graph file\n", da_file_name);
      goto cleanup;
    }

  while ((tag = gcov_read_unsigned ()))
    {
      unsigned length = gcov_read_unsigned ();
      unsigned long base = gcov_position ();

      if (tag == GCOV_TAG_OBJECT_SUMMARY)
	gcov_read_summary (&object_summary);
      else if (tag == GCOV_TAG_PROGRAM_SUMMARY)
	program_count++;
      else if (tag == GCOV_TAG_FUNCTION)
	{
	  unsigned ident = gcov_read_unsigned ();
	  struct function_info *fn_n = functions;

	  /* Try to find the function in the list.
	     To speed up the search, first start from the last function
	     found.   */
	  for (fn = fn ? fn->next : NULL; ; fn = fn->next)
	    {
	      if (fn)
		;
	      else if ((fn = fn_n))
		fn_n = NULL;
	      else
		{
		  fnotice (stderr, "%s:unknown function '%u'\n",
			   da_file_name, ident);
		  break;
		}
	      if (fn->ident == ident)
		break;
	    }

	  if (!fn)
	    ;
	  else if (gcov_read_unsigned () != fn->checksum)
	    {
	    mismatch:;
	      fnotice (stderr, "%s:profile mismatch for '%s'\n",
		       da_file_name, fn->name);
	      goto cleanup;
	    }
	}
      else if (tag == GCOV_TAG_FOR_COUNTER (GCOV_COUNTER_ARCS) && fn)
	{
	  if (length != GCOV_TAG_COUNTER_LENGTH (fn->num_counts))
	    goto mismatch;

	  if (!fn->counts)
	    fn->counts = XCNEWVEC (gcov_type, fn->num_counts);

	  for (ix = 0; ix != fn->num_counts; ix++)
	    fn->counts[ix] += gcov_read_counter ();
	}
      gcov_sync (base, length);
      if ((error = gcov_is_error ()))
	{
	  fnotice (stderr, error < 0 ? "%s:overflowed\n" : "%s:corrupted\n",
		   da_file_name);
	  goto cleanup;
	}
    }

  gcov_close ();
  return 0;
}

/* Solve the flow graph. Propagate counts from the instrumented arcs
   to the blocks and the uninstrumented arcs.  */

static void
solve_flow_graph (function_t *fn)
{
  unsigned ix;
  arc_t *arc;
  gcov_type *count_ptr = fn->counts;
  block_t *blk;
  block_t *valid_blocks = NULL;    /* valid, but unpropagated blocks.  */
  block_t *invalid_blocks = NULL;  /* invalid, but inferable blocks.  */

  if (fn->num_blocks < 2)
    fnotice (stderr, "%s:'%s' lacks entry and/or exit blocks\n",
	     bbg_file_name, fn->name);
  else
    {
      if (fn->blocks[0].num_pred)
	fnotice (stderr, "%s:'%s' has arcs to entry block\n",
		 bbg_file_name, fn->name);
      else
	/* We can't deduce the entry block counts from the lack of
	   predecessors.  */
	fn->blocks[0].num_pred = ~(unsigned)0;

      if (fn->blocks[fn->num_blocks - 1].num_succ)
	fnotice (stderr, "%s:'%s' has arcs from exit block\n",
		 bbg_file_name, fn->name);
      else
	/* Likewise, we can't deduce exit block counts from the lack
	   of its successors.  */
	fn->blocks[fn->num_blocks - 1].num_succ = ~(unsigned)0;
    }

  /* Propagate the measured counts, this must be done in the same
     order as the code in profile.c  */
  for (ix = 0, blk = fn->blocks; ix != fn->num_blocks; ix++, blk++)
    {
      block_t const *prev_dst = NULL;
      int out_of_order = 0;
      int non_fake_succ = 0;

      for (arc = blk->succ; arc; arc = arc->succ_next)
	{
	  if (!arc->fake)
	    non_fake_succ++;

	  if (!arc->on_tree)
	    {
	      if (count_ptr)
		arc->count = *count_ptr++;
	      arc->count_valid = 1;
	      blk->num_succ--;
	      arc->dst->num_pred--;
	    }
	  if (prev_dst && prev_dst > arc->dst)
	    out_of_order = 1;
	  prev_dst = arc->dst;
	}
      if (non_fake_succ == 1)
	{
	  /* If there is only one non-fake exit, it is an
	     unconditional branch.  */
	  for (arc = blk->succ; arc; arc = arc->succ_next)
	    if (!arc->fake)
	      {
		arc->is_unconditional = 1;
		/* If this block is instrumenting a call, it might be
		   an artificial block. It is not artificial if it has
		   a non-fallthrough exit, or the destination of this
		   arc has more than one entry.  Mark the destination
		   block as a return site, if none of those conditions
		   hold.  */
		if (blk->is_call_site && arc->fall_through
		    && arc->dst->pred == arc && !arc->pred_next)
		  arc->dst->is_call_return = 1;
	      }
	}

      /* Sort the successor arcs into ascending dst order. profile.c
	 normally produces arcs in the right order, but sometimes with
	 one or two out of order.  We're not using a particularly
	 smart sort.  */
      if (out_of_order)
	{
	  arc_t *start = blk->succ;
	  unsigned changes = 1;

	  while (changes)
	    {
	      arc_t *arc, *arc_p, *arc_n;

	      changes = 0;
	      for (arc_p = NULL, arc = start; (arc_n = arc->succ_next);)
		{
		  if (arc->dst > arc_n->dst)
		    {
		      changes = 1;
		      if (arc_p)
			arc_p->succ_next = arc_n;
		      else
			start = arc_n;
		      arc->succ_next = arc_n->succ_next;
		      arc_n->succ_next = arc;
		      arc_p = arc_n;
		    }
		  else
		    {
		      arc_p = arc;
		      arc = arc_n;
		    }
		}
	    }
	  blk->succ = start;
	}

      /* Place it on the invalid chain, it will be ignored if that's
	 wrong.  */
      blk->invalid_chain = 1;
      blk->chain = invalid_blocks;
      invalid_blocks = blk;
    }

  while (invalid_blocks || valid_blocks)
    {
      while ((blk = invalid_blocks))
	{
	  gcov_type total = 0;
	  const arc_t *arc;

	  invalid_blocks = blk->chain;
	  blk->invalid_chain = 0;
	  if (!blk->num_succ)
	    for (arc = blk->succ; arc; arc = arc->succ_next)
	      total += arc->count;
	  else if (!blk->num_pred)
	    for (arc = blk->pred; arc; arc = arc->pred_next)
	      total += arc->count;
	  else
	    continue;

	  blk->count = total;
	  blk->count_valid = 1;
	  blk->chain = valid_blocks;
	  blk->valid_chain = 1;
	  valid_blocks = blk;
	}
      while ((blk = valid_blocks))
	{
	  gcov_type total;
	  arc_t *arc, *inv_arc;

	  valid_blocks = blk->chain;
	  blk->valid_chain = 0;
	  if (blk->num_succ == 1)
	    {
	      block_t *dst;

	      total = blk->count;
	      inv_arc = NULL;
	      for (arc = blk->succ; arc; arc = arc->succ_next)
		{
		  total -= arc->count;
		  if (!arc->count_valid)
		    inv_arc = arc;
		}
	      dst = inv_arc->dst;
	      inv_arc->count_valid = 1;
	      inv_arc->count = total;
	      blk->num_succ--;
	      dst->num_pred--;
	      if (dst->count_valid)
		{
		  if (dst->num_pred == 1 && !dst->valid_chain)
		    {
		      dst->chain = valid_blocks;
		      dst->valid_chain = 1;
		      valid_blocks = dst;
		    }
		}
	      else
		{
		  if (!dst->num_pred && !dst->invalid_chain)
		    {
		      dst->chain = invalid_blocks;
		      dst->invalid_chain = 1;
		      invalid_blocks = dst;
		    }
		}
	    }
	  if (blk->num_pred == 1)
	    {
	      block_t *src;

	      total = blk->count;
	      inv_arc = NULL;
	      for (arc = blk->pred; arc; arc = arc->pred_next)
		{
		  total -= arc->count;
		  if (!arc->count_valid)
		    inv_arc = arc;
		}
	      src = inv_arc->src;
	      inv_arc->count_valid = 1;
	      inv_arc->count = total;
	      blk->num_pred--;
	      src->num_succ--;
	      if (src->count_valid)
		{
		  if (src->num_succ == 1 && !src->valid_chain)
		    {
		      src->chain = valid_blocks;
		      src->valid_chain = 1;
		      valid_blocks = src;
		    }
		}
	      else
		{
		  if (!src->num_succ && !src->invalid_chain)
		    {
		      src->chain = invalid_blocks;
		      src->invalid_chain = 1;
		      invalid_blocks = src;
		    }
		}
	    }
	}
    }

  /* If the graph has been correctly solved, every block will have a
     valid count.  */
  for (ix = 0; ix < fn->num_blocks; ix++)
    if (!fn->blocks[ix].count_valid)
      {
	fnotice (stderr, "%s:graph is unsolvable for '%s'\n",
		 bbg_file_name, fn->name);
	break;
      }
}


/* Increment totals in COVERAGE according to arc ARC.  */

static void
add_branch_counts (coverage_t *coverage, const arc_t *arc)
{
  if (arc->is_call_non_return)
    {
      coverage->calls++;
      if (arc->src->count)
	coverage->calls_executed++;
    }
  else if (!arc->is_unconditional)
    {
      coverage->branches++;
      if (arc->src->count)
	coverage->branches_executed++;
      if (arc->count)
	coverage->branches_taken++;
    }
}

/* Format a HOST_WIDE_INT as either a percent ratio, or absolute
   count.  If dp >= 0, format TOP/BOTTOM * 100 to DP decimal places.
   If DP is zero, no decimal point is printed. Only print 100% when
   TOP==BOTTOM and only print 0% when TOP=0.  If dp < 0, then simply
   format TOP.  Return pointer to a static string.  */

static char const *
format_gcov (gcov_type top, gcov_type bottom, int dp)
{
  static char buffer[20];

  if (dp >= 0)
    {
      float ratio = bottom ? (float)top / bottom : 0;
      int ix;
      unsigned limit = 100;
      unsigned percent;

      for (ix = dp; ix--; )
	limit *= 10;

      percent = (unsigned) (ratio * limit + (float)0.5);
      if (percent <= 0 && top)
	percent = 1;
      else if (percent >= limit && top != bottom)
	percent = limit - 1;
      ix = sprintf (buffer, "%.*u%%", dp + 1, percent);
      if (dp)
	{
	  dp++;
	  do
	    {
	      buffer[ix+1] = buffer[ix];
	      ix--;
	    }
	  while (dp--);
	  buffer[ix + 1] = '.';
	}
    }
  else
    sprintf (buffer, HOST_WIDEST_INT_PRINT_DEC, (HOST_WIDEST_INT)top);

  return buffer;
}


/* Output summary info for a function.  */

static void
function_summary (const coverage_t *coverage, const char *title)
{
  fnotice (stdout, "%s '%s'\n", title, coverage->name);

  if (coverage->lines)
    fnotice (stdout, "Lines executed:%s of %d\n",
	     format_gcov (coverage->lines_executed, coverage->lines, 2),
	     coverage->lines);
  else
    fnotice (stdout, "No executable lines\n");

  if (flag_branches)
    {
      if (coverage->branches)
	{
	  fnotice (stdout, "Branches executed:%s of %d\n",
		   format_gcov (coverage->branches_executed,
				coverage->branches, 2),
		   coverage->branches);
	  fnotice (stdout, "Taken at least once:%s of %d\n",
		   format_gcov (coverage->branches_taken,
				coverage->branches, 2),
		   coverage->branches);
	}
      else
	fnotice (stdout, "No branches\n");
      if (coverage->calls)
	fnotice (stdout, "Calls executed:%s of %d\n",
		 format_gcov (coverage->calls_executed, coverage->calls, 2),
		 coverage->calls);
      else
	fnotice (stdout, "No calls\n");
    }
}

/* Generate an output file name. LONG_OUTPUT_NAMES and PRESERVE_PATHS
   affect name generation. With preserve_paths we create a filename
   from all path components of the source file, replacing '/' with
   '#', without it we simply take the basename component. With
   long_output_names we prepend the processed name of the input file
   to each output name (except when the current source file is the
   input file, so you don't get a double concatenation). The two
   components are separated by '##'. Also '.' filename components are
   removed and '..'  components are renamed to '^'.  */

static char *
make_gcov_file_name (const char *input_name, const char *src_name)
{
  const char *cptr;
  char *name;

  if (flag_long_names && input_name && strcmp (src_name, input_name))
    {
      name = XNEWVEC (char, strlen (src_name) + strlen (input_name) + 10);
      name[0] = 0;
      /* Generate the input filename part.  */
      cptr = flag_preserve_paths ? NULL : lbasename (input_name);
      strcat (name, cptr ? cptr : input_name);
      strcat (name, "##");
    }
  else
    {
      name = XNEWVEC (char, strlen (src_name) + 10);
      name[0] = 0;
    }

  /* Generate the source filename part.  */

  cptr = flag_preserve_paths ? NULL : lbasename (src_name);
  strcat (name, cptr ? cptr : src_name);

  if (flag_preserve_paths)
    {
      /* Convert '/' and '\' to '#', remove '/./', convert '/../' to '/^/',
	 convert ':' to '~' on DOS based file system.  */
      char *pnew = name, *pold = name;

      /* First check for leading drive separator.  */

      while (*pold != '\0')
	{
	  if (*pold == '/' || *pold == '\\')
	    {
	      *pnew++ = '#';
	      pold++;
	    }
#if defined (HAVE_DOS_BASED_FILE_SYSTEM)
	  else if (*pold == ':')
	    {
	      *pnew++ = '~';
	      pold++;
	    }
#endif
	  else if ((*pold == '/' && strstr (pold, "/./") == pold)
		   || (*pold == '\\' && strstr (pold, "\\.\\") == pold))
	      pold += 3;
	  else if (*pold == '/' && strstr (pold, "/../") == pold)
	    {
	      strcpy (pnew, "/^/");
	      pnew += 3;
	      pold += 4;
	    }
	  else if (*pold == '\\' && strstr (pold, "\\..\\") == pold)
	    {
	      strcpy (pnew, "\\^\\");
	      pnew += 3;
	      pold += 4;
	    }
	  else
	    *pnew++ = *pold++;
	}

      *pnew = '\0';
    }

  strcat (name, ".gcov");
  return name;
}

/* Scan through the bb_data for each line in the block, increment
   the line number execution count indicated by the execution count of
   the appropriate basic block.  */

static void
add_line_counts (coverage_t *coverage, function_t *fn)
{
  unsigned ix;
  line_t *line = NULL; /* This is propagated from one iteration to the
			  next.  */

  /* Scan each basic block.  */
  for (ix = 0; ix != fn->num_blocks; ix++)
    {
      block_t *block = &fn->blocks[ix];
      unsigned *encoding;
      const source_t *src = NULL;
      unsigned jx;

      if (block->count && ix && ix + 1 != fn->num_blocks)
	fn->blocks_executed++;
      for (jx = 0, encoding = block->u.line.encoding;
	   jx != block->u.line.num; jx++, encoding++)
	if (!*encoding)
	  {
	    unsigned src_n = *++encoding;

	    for (src = sources; src->index != src_n; src = src->next)
	      continue;
	    jx++;
	  }
	else
	  {
	    line = &src->lines[*encoding];

	    if (coverage)
	      {
		if (!line->exists)
		  coverage->lines++;
		if (!line->count && block->count)
		  coverage->lines_executed++;
	      }
	    line->exists = 1;
	    line->count += block->count;
	  }
      free (block->u.line.encoding);
      block->u.cycle.arc = NULL;
      block->u.cycle.ident = ~0U;

      if (!ix || ix + 1 == fn->num_blocks)
	/* Entry or exit block */;
      else if (flag_all_blocks)
	{
	  line_t *block_line = line ? line : &fn->src->lines[fn->line];

	  block->chain = block_line->u.blocks;
	  block_line->u.blocks = block;
	}
      else if (flag_branches)
	{
	  arc_t *arc;

	  for (arc = block->succ; arc; arc = arc->succ_next)
	    {
	      arc->line_next = line->u.branches;
	      line->u.branches = arc;
	      if (coverage && !arc->is_unconditional)
		add_branch_counts (coverage, arc);
	    }
	}
    }
  if (!line)
    fnotice (stderr, "%s:no lines for '%s'\n", bbg_file_name, fn->name);
}

/* Accumulate the line counts of a file.  */

static void
accumulate_line_counts (source_t *src)
{
  line_t *line;
  function_t *fn, *fn_p, *fn_n;
  unsigned ix;

  /* Reverse the function order.  */
  for (fn = src->functions, fn_p = NULL; fn;
       fn_p = fn, fn = fn_n)
    {
      fn_n = fn->line_next;
      fn->line_next = fn_p;
    }
  src->functions = fn_p;

  for (ix = src->num_lines, line = src->lines; ix--; line++)
    {
      if (!flag_all_blocks)
	{
	  arc_t *arc, *arc_p, *arc_n;

	  /* Total and reverse the branch information.  */
	  for (arc = line->u.branches, arc_p = NULL; arc;
	       arc_p = arc, arc = arc_n)
	    {
	      arc_n = arc->line_next;
	      arc->line_next = arc_p;

	      add_branch_counts (&src->coverage, arc);
	    }
	  line->u.branches = arc_p;
	}
      else if (line->u.blocks)
	{
	  /* The user expects the line count to be the number of times
	     a line has been executed. Simply summing the block count
	     will give an artificially high number.  The Right Thing
	     is to sum the entry counts to the graph of blocks on this
	     line, then find the elementary cycles of the local graph
	     and add the transition counts of those cycles.  */
	  block_t *block, *block_p, *block_n;
	  gcov_type count = 0;

	  /* Reverse the block information.  */
	  for (block = line->u.blocks, block_p = NULL; block;
	       block_p = block, block = block_n)
	    {
	      block_n = block->chain;
	      block->chain = block_p;
	      block->u.cycle.ident = ix;
	    }
	  line->u.blocks = block_p;

	  /* Sum the entry arcs.  */
	  for (block = line->u.blocks; block; block = block->chain)
	    {
	      arc_t *arc;

	      for (arc = block->pred; arc; arc = arc->pred_next)
		{
		  if (arc->src->u.cycle.ident != ix)
		    count += arc->count;
		  if (flag_branches)
		    add_branch_counts (&src->coverage, arc);
		}

	      /* Initialize the cs_count.  */
	      for (arc = block->succ; arc; arc = arc->succ_next)
		arc->cs_count = arc->count;
	    }

	  /* Find the loops. This uses the algorithm described in
	     Tiernan 'An Efficient Search Algorithm to Find the
	     Elementary Circuits of a Graph', CACM Dec 1970. We hold
	     the P array by having each block point to the arc that
	     connects to the previous block. The H array is implicitly
	     held because of the arc ordering, and the block's
	     previous arc pointer.

	     Although the algorithm is O(N^3) for highly connected
	     graphs, at worst we'll have O(N^2), as most blocks have
	     only one or two exits. Most graphs will be small.

	     For each loop we find, locate the arc with the smallest
	     transition count, and add that to the cumulative
	     count.  Decrease flow over the cycle and remove the arc
	     from consideration.  */
	  for (block = line->u.blocks; block; block = block->chain)
	    {
	      block_t *head = block;
	      arc_t *arc;

	    next_vertex:;
	      arc = head->succ;
	    current_vertex:;
	      while (arc)
		{
		  block_t *dst = arc->dst;
		  if (/* Already used that arc.  */
		      arc->cycle
		      /* Not to same graph, or before first vertex.  */
		      || dst->u.cycle.ident != ix
		      /* Already in path.  */
		      || dst->u.cycle.arc)
		    {
		      arc = arc->succ_next;
		      continue;
		    }

		  if (dst == block)
		    {
		      /* Found a closing arc.  */
		      gcov_type cycle_count = arc->cs_count;
		      arc_t *cycle_arc = arc;
		      arc_t *probe_arc;

		      /* Locate the smallest arc count of the loop.  */
		      for (dst = head; (probe_arc = dst->u.cycle.arc);
			   dst = probe_arc->src)
			if (cycle_count > probe_arc->cs_count)
			  {
			    cycle_count = probe_arc->cs_count;
			    cycle_arc = probe_arc;
			  }

		      count += cycle_count;
		      cycle_arc->cycle = 1;

		      /* Remove the flow from the cycle.  */
		      arc->cs_count -= cycle_count;
		      for (dst = head; (probe_arc = dst->u.cycle.arc);
			   dst = probe_arc->src)
			probe_arc->cs_count -= cycle_count;

		      /* Unwind to the cyclic arc.  */
		      while (head != cycle_arc->src)
			{
			  arc = head->u.cycle.arc;
			  head->u.cycle.arc = NULL;
			  head = arc->src;
			}
		      /* Move on.  */
		      arc = arc->succ_next;
		      continue;
		    }

		  /* Add new block to chain.  */
		  dst->u.cycle.arc = arc;
		  head = dst;
		  goto next_vertex;
		}
	      /* We could not add another vertex to the path. Remove
		 the last vertex from the list.  */
	      arc = head->u.cycle.arc;
	      if (arc)
		{
		  /* It was not the first vertex. Move onto next arc.  */
		  head->u.cycle.arc = NULL;
		  head = arc->src;
		  arc = arc->succ_next;
		  goto current_vertex;
		}
	      /* Mark this block as unusable.  */
	      block->u.cycle.ident = ~0U;
	    }

	  line->count = count;
	}

      if (line->exists)
	{
	  src->coverage.lines++;
	  if (line->count)
	    src->coverage.lines_executed++;
	}
    }
}

/* Output information about ARC number IX.  Returns nonzero if
   anything is output.  */

static int
output_branch_count (FILE *gcov_file, int ix, const arc_t *arc)
{

  if (arc->is_call_non_return)
    {
      if (arc->src->count)
	{
	  fnotice (gcov_file, "call   %2d returned %s\n", ix,
		   format_gcov (arc->src->count - arc->count,
				arc->src->count, -flag_counts));
	}
      else
	fnotice (gcov_file, "call   %2d never executed\n", ix);
    }
  else if (!arc->is_unconditional)
    {
      if (arc->src->count)
	fnotice (gcov_file, "branch %2d taken %s%s\n", ix,
		 format_gcov (arc->count, arc->src->count, -flag_counts),
		 arc->fall_through ? " (fallthrough)" : "");
      else
	fnotice (gcov_file, "branch %2d never executed\n", ix);
    }
  else if (flag_unconditional && !arc->dst->is_call_return)
    {
      if (arc->src->count)
	fnotice (gcov_file, "unconditional %2d taken %s\n", ix,
		 format_gcov (arc->count, arc->src->count, -flag_counts));
      else
	fnotice (gcov_file, "unconditional %2d never executed\n", ix);
    }
  else
    return 0;
  return 1;

}

/* Read in the source file one line at a time, and output that line to
   the gcov file preceded by its execution count and other
   information.  */

static void
output_lines (FILE *gcov_file, const source_t *src)
{
  FILE *source_file;
  unsigned line_num;	/* current line number.  */
  const line_t *line;           /* current line info ptr.  */
  char string[STRING_SIZE];     /* line buffer.  */
  char const *retval = "";	/* status of source file reading.  */
  function_t *fn = NULL;

  fprintf (gcov_file, "%9s:%5d:Source:%s\n", "-", 0, src->name);
  if (!multiple_files)
    {
      fprintf (gcov_file, "%9s:%5d:Graph:%s\n", "-", 0, bbg_file_name);
      fprintf (gcov_file, "%9s:%5d:Data:%s\n", "-", 0,
	       no_data_file ? "-" : da_file_name);
      fprintf (gcov_file, "%9s:%5d:Runs:%u\n", "-", 0,
	       object_summary.ctrs[GCOV_COUNTER_ARCS].runs);
    }
  fprintf (gcov_file, "%9s:%5d:Programs:%u\n", "-", 0, program_count);

  source_file = fopen (src->name, "r");
  if (!source_file)
    {
      fnotice (stderr, "%s:cannot open source file\n", src->name);
      retval = NULL;
    }
  else if (src->file_time == 0)
    fprintf (gcov_file, "%9s:%5d:Source is newer than graph\n", "-", 0);

  if (flag_branches)
    fn = src->functions;

  for (line_num = 1, line = &src->lines[line_num];
       line_num < src->num_lines; line_num++, line++)
    {
      for (; fn && fn->line == line_num; fn = fn->line_next)
	{
	  arc_t *arc = fn->blocks[fn->num_blocks - 1].pred;
	  gcov_type return_count = fn->blocks[fn->num_blocks - 1].count;
	  
	  for (; arc; arc = arc->pred_next)
	    if (arc->fake)
	      return_count -= arc->count;
	  
	  fprintf (gcov_file, "function %s", fn->name);
	  fprintf (gcov_file, " called %s",
		   format_gcov (fn->blocks[0].count, 0, -1));
	  fprintf (gcov_file, " returned %s",
		   format_gcov (return_count, fn->blocks[0].count, 0));
	  fprintf (gcov_file, " blocks executed %s",
		   format_gcov (fn->blocks_executed, fn->num_blocks - 2, 0));
	  fprintf (gcov_file, "\n");
	}

      /* For lines which don't exist in the .bb file, print '-' before
	 the source line.  For lines which exist but were never
	 executed, print '#####' before the source line.  Otherwise,
	 print the execution count before the source line.  There are
	 16 spaces of indentation added before the source line so that
	 tabs won't be messed up.  */
      fprintf (gcov_file, "%9s:%5u:",
	       !line->exists ? "-" : !line->count ? "#####"
	       : format_gcov (line->count, 0, -1), line_num);

      if (retval)
	{
	  /* Copy source line.  */
	  do
	    {
	      retval = fgets (string, STRING_SIZE, source_file);
	      if (!retval)
		break;
	      fputs (retval, gcov_file);
	    }
	  while (!retval[0] || retval[strlen (retval) - 1] != '\n');
	}
      if (!retval)
	fputs ("/*EOF*/\n", gcov_file);

      if (flag_all_blocks)
	{
	  block_t *block;
	  arc_t *arc;
	  int ix, jx;

	  for (ix = jx = 0, block = line->u.blocks; block;
	       block = block->chain)
	    {
	      if (!block->is_call_return)
		fprintf (gcov_file, "%9s:%5u-block %2d\n",
			 !line->exists ? "-" : !block->count ? "$$$$$"
			 : format_gcov (block->count, 0, -1),
			 line_num, ix++);
	      if (flag_branches)
		for (arc = block->succ; arc; arc = arc->succ_next)
		  jx += output_branch_count (gcov_file, jx, arc);
	    }
	}
      else if (flag_branches)
	{
	  int ix;
	  arc_t *arc;

	  for (ix = 0, arc = line->u.branches; arc; arc = arc->line_next)
	    ix += output_branch_count (gcov_file, ix, arc);
	}
    }

  /* Handle all remaining source lines.  There may be lines after the
     last line of code.  */
  if (retval)
    {
      for (; (retval = fgets (string, STRING_SIZE, source_file)); line_num++)
	{
	  fprintf (gcov_file, "%9s:%5u:%s", "-", line_num, retval);

	  while (!retval[0] || retval[strlen (retval) - 1] != '\n')
	    {
	      retval = fgets (string, STRING_SIZE, source_file);
	      if (!retval)
		break;
	      fputs (retval, gcov_file);
	    }
	}
    }

  if (source_file)
    fclose (source_file);
}