/* Output routines for graphical representation.
   Copyright (C) 1998-2012
   Free Software Foundation, Inc.
   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
   Rewritten for DOT output by Steven Bosscher, 2012.

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.

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 "config.h"
#include "system.h"
#include "coretypes.h"
#include "diagnostic-core.h" /* for fatal_error */
#include "basic-block.h"
#include "graph.h"
#include "dumpfile.h"
#include "pretty-print.h"

/* DOT files with the .dot extension are recognized as document templates
   by a well-known piece of word processing software out of Redmond, WA.
   Therefore some recommend using the .gv extension instead.  Obstinately
   ignore that recommendatition...  */
static const char *const graph_ext = ".dot";

/* Open a file with MODE for dumping our graph to.
   Return the file pointer.  */
static FILE *
open_graph_file (const char *base, const char *mode)
{
  size_t namelen = strlen (base);
  size_t extlen = strlen (graph_ext) + 1;
  char *buf = XALLOCAVEC (char, namelen + extlen);
  FILE *fp;

  memcpy (buf, base, namelen);
  memcpy (buf + namelen, graph_ext, extlen);

  fp = fopen (buf, mode);
  if (fp == NULL)
    fatal_error ("can%'t open %s: %m", buf);

  return fp;
}

/* Return a pretty-print buffer for output to file FP.  */

static pretty_printer *
init_graph_slim_pretty_print (FILE *fp)
{
  static bool initialized = false;
  static pretty_printer graph_slim_pp;

  if (! initialized)
    {
      pp_construct (&graph_slim_pp, /*prefix=*/NULL, /*linewidth=*/0);
      initialized = true;
    }
  else
    gcc_assert (! pp_last_position_in_text (&graph_slim_pp));

  graph_slim_pp.buffer->stream = fp;
  return &graph_slim_pp;
}

/* Draw a basic block BB belonging to the function with FUNCDEF_NO
   as its unique number.  */
static void
draw_cfg_node (pretty_printer *pp, int funcdef_no, basic_block bb)
{
  const char *shape;
  const char *fillcolor;

  if (bb->index == ENTRY_BLOCK || bb->index == EXIT_BLOCK)
    {
      shape = "Mdiamond";
      fillcolor = "white";
    }
  else
    {
      shape = "record";
      fillcolor =
	BB_PARTITION (bb) == BB_HOT_PARTITION ? "lightpink"
	: BB_PARTITION (bb) == BB_COLD_PARTITION ? "lightblue"
	: "lightgrey";
    }

  pp_printf (pp,
	     "\tfn_%d_basic_block_%d "
	     "[shape=%s,style=filled,fillcolor=%s,label=\"",
	     funcdef_no, bb->index, shape, fillcolor);

  if (bb->index == ENTRY_BLOCK)
    pp_string (pp, "ENTRY");
  else if (bb->index == EXIT_BLOCK)
    pp_string (pp, "EXIT");
  else
    {
      pp_character (pp, '{');
      pp_write_text_to_stream (pp);
      dump_bb_for_graph (pp, bb);
      pp_character (pp, '}');
    }

  pp_string (pp, "\"];\n\n");
  pp_flush (pp);
}

/* Draw all successor edges of a basic block BB belonging to the function
   with FUNCDEF_NO as its unique number.  */
static void
draw_cfg_node_succ_edges (pretty_printer *pp, int funcdef_no, basic_block bb)
{
  edge e;
  edge_iterator ei;
  FOR_EACH_EDGE (e, ei, bb->succs)
    {
      const char *style = "\"solid,bold\"";
      const char *color = "black";
      int weight = 10;

      if (e->flags & EDGE_FAKE)
	{
	  style = "dotted";
	  color = "green";
	  weight = 0;
	}
      else if (e->flags & EDGE_DFS_BACK)
	{
	  style = "\"dotted,bold\"";
	  color = "blue";
	  weight = 10;
	}
      else if (e->flags & EDGE_FALLTHRU)
	{
	  color = "blue";
	  weight = 100;
	}

      if (e->flags & EDGE_ABNORMAL)
	color = "red";

      pp_printf (pp,
		 "\tfn_%d_basic_block_%d:s -> fn_%d_basic_block_%d:n "
		 "[style=%s,color=%s,weight=%d,constraint=%s];\n",
		 funcdef_no, e->src->index,
		 funcdef_no, e->dest->index,
		 style, color, weight,
		 (e->flags & (EDGE_FAKE | EDGE_DFS_BACK)) ? "false" : "true");
    }
  pp_flush (pp);
}

/* Print a graphical representation of the CFG of function FUN.  */

void
print_graph_cfg (const char *base, struct function *fun)
{
  const char *funcname = function_name (fun);
  int funcdef_no = fun->funcdef_no;
  FILE *fp = open_graph_file (base, "a");
  int *rpo = XNEWVEC (int, n_basic_blocks);
  basic_block bb;
  int i, n;
  pretty_printer *pp = init_graph_slim_pretty_print (fp);

  pp_printf (pp, "subgraph \"%s\" {\n"
	         "\tcolor=\"black\";\n"
		 "\tlabel=\"%s\";\n",
		 funcname, funcname);

  /* First print all basic blocks.
     Visit the blocks in reverse post order to get a good ranking
     of the nodes.  */
  n = pre_and_rev_post_order_compute (NULL, rpo, true);
  for (i = 0; i < n; i++)
    draw_cfg_node (pp, funcdef_no, BASIC_BLOCK (rpo[i]));

  /* Draw all edges at the end to get subgraphs right for GraphViz,
     which requires nodes to be defined before edges to cluster
     nodes properly.

     Draw retreating edges as not constraining, this makes the layout
     of the graph better.  (??? Calling mark_dfs_back may change the
     compiler's behavior when dumping, but computing back edges here
     for ourselves is also not desirable.)  */
  mark_dfs_back_edges ();
  FOR_ALL_BB (bb)
    draw_cfg_node_succ_edges (pp, funcdef_no, bb);

  pp_printf (pp, "\t}\n");
  pp_flush (pp);
  fclose (fp);
}

/* Start the dump of a graph.  */
static void
start_graph_dump (FILE *fp)
{
  fputs ("digraph \"\" {\n"
	 "overlap=false;\n",
	 fp);
}

/* End the dump of a graph.  */
static void
end_graph_dump (FILE *fp)
{
  fputs ("}\n", fp);
}

/* Similar as clean_dump_file, but this time for graph output files.  */
void
clean_graph_dump_file (const char *base)
{
  FILE *fp = open_graph_file (base, "w");
  start_graph_dump (fp);
  fclose (fp);
}


/* Do final work on the graph output file.  */
void
finish_graph_dump_file (const char *base)
{
  FILE *fp = open_graph_file (base, "a");
  end_graph_dump (fp);
  fclose (fp);
}