/* Generate Graphiviz format .dot dump of functions control flow graph,
   similar as the gcc internal vcg dump.
   Copyright (C) 2010 by
   Author: "Dennis, CHENG Renquan" <crquan@fedoraproject.org>

This software 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.

It 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 GCC; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */

#include "gcc-plugin.h"
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "tree.h"
#include "rtl.h"
#include "basic-block.h"
#include "function.h"
#include "langhooks.h"
#include "tree-flow.h"
#include "tree-dump.h"
#include "tree-pass.h"
#include "toplev.h"

int plugin_is_GPL_compatible;

/* global variables */
static const char *plugin_name;
static int dot_nr;
static FILE *dot_file = NULL;
static bool disabled = false;

static struct plugin_info _version_help_info =
{
  "0.1",			/* version */
  "Dump internal gimple cfg into Graphviz .dot format",
				/* help */
};

static void
gimple_cfg2dot (void)
{
  edge e;
  edge_iterator ei;
  basic_block bb;

  const char *funcname
    = lang_hooks.decl_printable_name (current_function_decl, 2);

  /* Write the file header.  */
  fprintf (dot_file, "// Function %s\n", funcname);
  fprintf (dot_file, "digraph graph_%s {\n\n", funcname);
  fprintf (dot_file, "  graph [ label=%s, labelloc=top ];\n\n", funcname);

  /* Write blocks and edges.  */
  FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs)
    {
      fprintf (dot_file, "  ENTRY -> %d", e->dest->index);

      /* how to represent this in Graphviz dot ??? */
      /* if (e->flags & EDGE_FAKE) */
      /* 	fprintf (file, " linestyle: dotted priority: 10"); */
      /* else */
      /* 	fprintf (file, " linestyle: solid priority: 100"); */

      fprintf (dot_file, "\n");
    }
  fputc ('\n', dot_file);

  FOR_EACH_BB (bb)
    {
      enum gimple_code head_code, end_code;
      const char *head_name, *end_name;
      int head_line = 0;
      int end_line = 0;
      gimple first = first_stmt (bb);
      gimple last = last_stmt (bb);

      if (first)
	{
	  head_code = gimple_code (first);
	  head_name = gimple_code_name[head_code];
	  head_line = get_lineno (first);
	}
      else
	head_name = "no-statement";

      if (last)
	{
	  end_code = gimple_code (last);
	  end_name = gimple_code_name[end_code];
	  end_line = get_lineno (last);
	}
      else
	end_name = "no-statement";

      fprintf (dot_file, "  %d [ label=\"#%d\\n%s (%d)\\n%s (%d)\" ]\n",
	       bb->index, bb->index, head_name, head_line, end_name,
	       end_line);

      FOR_EACH_EDGE (e, ei, bb->succs)
	{
	  if (e->dest == EXIT_BLOCK_PTR)
	    fprintf (dot_file, "  %d -> EXIT\n", bb->index);
	  else
	    {
	      fprintf (dot_file, "  %d -> %d", bb->index, e->dest->index);

	      /* if (e->flags & EDGE_FAKE) */
	      /*   fprintf (file, " priority: 10 linestyle: dotted"); */
	      /* else */
	      /*   fprintf (file, " priority: 100 linestyle: solid"); */

	      fprintf (dot_file, "\n");
	    }
	}

      if (bb->next_bb != EXIT_BLOCK_PTR)
	fputc ('\n', dot_file);
    }

  fprintf (dot_file, "}\n\n");
}

static void
open_dump_file (void)
{
  dot_nr = dump_register (".dot", NULL, NULL, TDF_TREE);

  /* manually set dfi->state to -1 enable it,
     because the dump_enable is static, cannot be used
     by plugins.
  */
  get_dump_file_info (dot_nr)->state = -1;
  dot_file = dump_begin (dot_nr, NULL);
  if (dot_file)
    {
      time_t now;
      time (&now);
      fprintf (dot_file,
	       "\n// Generated by %s gcc plugin %s at %s\n",
	       plugin_name, _version_help_info.version,
	       ctime (&now));
    }
  else
    {
      warning (0, "dot dump file open failed, diable this pass for following functions.");
      disabled = true;
    }
}

static bool
gate_enabled (void)
{
  return !disabled;
}

static unsigned int
execute_pass_cfg2dot (void)
{
  if (!dot_file)
    open_dump_file ();

  gimple_cfg2dot ();

  return 0;
}

static struct gimple_opt_pass pass_cfg2dot =
{
  {
    GIMPLE_PASS,
    "*cfg2dot",				/* name */
    gate_enabled,			/* gate */
    execute_pass_cfg2dot,		/* execute */
    NULL,				/* sub */
    NULL,				/* next */
    0,					/* static_pass_number */
    TV_NONE,				/* tv_id */
    PROP_cfg,				/* properties_required */
    0,					/* properties_provided */
    0,					/* properties_destroyed */
    0,					/* todo_flags_start */
    0					/* todo_flags_finish */
  }
};

static void
plugin_finish_unit (void *gcc_data,
		    void *user_data)
{
  if (dot_file)
    {
      dump_end (dot_nr, dot_file);
      dot_file = NULL;
      dot_nr = 0;
    }
}

int
plugin_init (struct plugin_name_args *plugin_info,
	     struct plugin_gcc_version *version)
{
  struct register_pass_info regi_info;

  plugin_name = plugin_info->base_name;

  register_callback (plugin_name,
		     PLUGIN_INFO,
		     NULL,
		     &_version_help_info);
  register_callback (plugin_name,
		     PLUGIN_FINISH_UNIT,
		     plugin_finish_unit,
		     NULL);

  regi_info.pass = &pass_cfg2dot.pass;
  regi_info.reference_pass_name = "cfg";
  regi_info.ref_pass_instance_number = 0;
  regi_info.pos_op = PASS_POS_INSERT_AFTER;

  register_callback (plugin_name,
		     PLUGIN_PASS_MANAGER_SETUP,
		     NULL,
		     &regi_info);

  return 0;
}