gcc/graph.c

   1 /* Output routines for graphical representation.
   2    Copyright (C) 1998-2013 Free Software Foundation, Inc.
   3    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
   4    Rewritten for DOT output by Steven Bosscher, 2012.
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 3, or (at your option) any later
  11 version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  21
  22 #include "config.h"
  23 #include "system.h"
  24 #include "coretypes.h"
  25 #include "diagnostic-core.h" /* for fatal_error */
  26 #include "sbitmap.h"
  27 #include "basic-block.h"
  28 #include "cfgloop.h"
  29 #include "graph.h"
  30 #include "dumpfile.h"
  31 #include "pretty-print.h"
  32
  33 /* DOT files with the .dot extension are recognized as document templates
  34    by a well-known piece of word processing software out of Redmond, WA.
  35    Therefore some recommend using the .gv extension instead.  Obstinately
  36    ignore that recommendation...  */
  37 static const char *const graph_ext = ".dot";
  38
  39 /* Open a file with MODE for dumping our graph to.
  40    Return the file pointer.  */
  41 static FILE *
  42 open_graph_file (const char *base, const char *mode)
  43 {
  44   size_t namelen = strlen (base);
  45   size_t extlen = strlen (graph_ext) + 1;
  46   char *buf = XALLOCAVEC (char, namelen + extlen);
  47   FILE *fp;
  48
  49   memcpy (buf, base, namelen);
  50   memcpy (buf + namelen, graph_ext, extlen);
  51
  52   fp = fopen (buf, mode);
  53   if (fp == NULL)
  54     fatal_error ("can%'t open %s: %m", buf);
  55
  56   return fp;
  57 }
  58
  59 /* Return a pretty-print buffer for output to file FP.  */
  60
  61 static pretty_printer *
  62 init_graph_slim_pretty_print (FILE *fp)
  63 {
  64   static bool initialized = false;
  65   static pretty_printer graph_slim_pp;
  66
  67   if (! initialized)
  68     {
  69       pp_construct (&graph_slim_pp, /*prefix=*/NULL, /*linewidth=*/0);
  70       initialized = true;
  71     }
  72   else
  73     gcc_assert (! pp_last_position_in_text (&graph_slim_pp));
  74
  75   graph_slim_pp.buffer->stream = fp;
  76   return &graph_slim_pp;
  77 }
  78
  79 /* Draw a basic block BB belonging to the function with FUNCDEF_NO
  80    as its unique number.  */
  81 static void
  82 draw_cfg_node (pretty_printer *pp, int funcdef_no, basic_block bb)
  83 {
  84   const char *shape;
  85   const char *fillcolor;
  86
  87   if (bb->index == ENTRY_BLOCK || bb->index == EXIT_BLOCK)
  88     {
  89       shape = "Mdiamond";
  90       fillcolor = "white";
  91     }
  92   else
  93     {
  94       shape = "record";
  95       fillcolor =
  96         BB_PARTITION (bb) == BB_HOT_PARTITION ? "lightpink"
  97         : BB_PARTITION (bb) == BB_COLD_PARTITION ? "lightblue"
  98         : "lightgrey";
  99     }
 100
 101   pp_printf (pp,
 102              "\tfn_%d_basic_block_%d "
 103              "[shape=%s,style=filled,fillcolor=%s,label=\"",
 104              funcdef_no, bb->index, shape, fillcolor);
 105
 106   if (bb->index == ENTRY_BLOCK)
 107     pp_string (pp, "ENTRY");
 108   else if (bb->index == EXIT_BLOCK)
 109     pp_string (pp, "EXIT");
 110   else
 111     {
 112       pp_character (pp, '{');
 113       pp_write_text_to_stream (pp);
 114       dump_bb_for_graph (pp, bb);
 115       pp_character (pp, '}');
 116     }
 117
 118   pp_string (pp, "\"];\n\n");
 119   pp_flush (pp);
 120 }
 121
 122 /* Draw all successor edges of a basic block BB belonging to the function
 123    with FUNCDEF_NO as its unique number.  */
 124 static void
 125 draw_cfg_node_succ_edges (pretty_printer *pp, int funcdef_no, basic_block bb)
 126 {
 127   edge e;
 128   edge_iterator ei;
 129   FOR_EACH_EDGE (e, ei, bb->succs)
 130     {
 131       const char *style = "\"solid,bold\"";
 132       const char *color = "black";
 133       int weight = 10;
 134
 135       if (e->flags & EDGE_FAKE)
 136         {
 137           style = "dotted";
 138           color = "green";
 139           weight = 0;
 140         }
 141       else if (e->flags & EDGE_DFS_BACK)
 142         {
 143           style = "\"dotted,bold\"";
 144           color = "blue";
 145           weight = 10;
 146         }
 147       else if (e->flags & EDGE_FALLTHRU)
 148         {
 149           color = "blue";
 150           weight = 100;
 151         }
 152
 153       if (e->flags & EDGE_ABNORMAL)
 154         color = "red";
 155
 156       pp_printf (pp,
 157                  "\tfn_%d_basic_block_%d:s -> fn_%d_basic_block_%d:n "
 158                  "[style=%s,color=%s,weight=%d,constraint=%s];\n",
 159                  funcdef_no, e->src->index,
 160                  funcdef_no, e->dest->index,
 161                  style, color, weight,
 162                  (e->flags & (EDGE_FAKE | EDGE_DFS_BACK)) ? "false" : "true");
 163     }
 164   pp_flush (pp);
 165 }
 166
 167 /* Draw all the basic blocks in the CFG in case loops are not available.
 168    First compute a topological order of the blocks to get a good ranking of
 169    the nodes.  Then, if any nodes are not reachable from ENTRY, add them at
 170    the end.  */
 171
 172 static void
 173 draw_cfg_nodes_no_loops (pretty_printer *pp, struct function *fun)
 174 {
 175   int *rpo = XNEWVEC (int, n_basic_blocks_for_function (fun));
 176   int i, n;
 177   sbitmap visited;
 178
 179   visited = sbitmap_alloc (last_basic_block);
 180   bitmap_clear (visited);
 181
 182   /* FIXME: pre_and_rev_post_order_compute only works if fun == cfun.  */
 183   n = pre_and_rev_post_order_compute (NULL, rpo, true);
 184   for (i = 0; i < n; i++)
 185     {
 186       basic_block bb = BASIC_BLOCK (rpo[i]);
 187       draw_cfg_node (pp, fun->funcdef_no, bb);
 188       bitmap_set_bit (visited, bb->index);
 189     }
 190   free (rpo);
 191
 192   if (n != n_basic_blocks_for_function (fun))
 193     {
 194       /* Some blocks are unreachable.  We still want to dump them.  */
 195       basic_block bb;
 196       FOR_ALL_BB_FN (bb, fun)
 197         if (! bitmap_bit_p (visited, bb->index))
 198           draw_cfg_node (pp, fun->funcdef_no, bb);
 199     }
 200
 201   sbitmap_free (visited);
 202 }
 203
 204 /* Draw all the basic blocks in LOOP.  Print the blocks in breath-first
 205    order to get a good ranking of the nodes.  This function is recursive:
 206    It first prints inner loops, then the body of LOOP itself.  */
 207
 208 static void
 209 draw_cfg_nodes_for_loop (pretty_printer *pp, int funcdef_no,
 210                          struct loop *loop)
 211 {
 212   basic_block *body;
 213   unsigned int i;
 214   const char *fillcolors[3] = { "grey88", "grey77", "grey66" };
 215
 216   if (loop->header != NULL
 217       && loop->latch != EXIT_BLOCK_PTR)
 218     pp_printf (pp,
 219                "\tsubgraph cluster_%d_%d {\n"
 220                "\tstyle=\"filled\";\n"
 221                "\tcolor=\"darkgreen\";\n"
 222                "\tfillcolor=\"%s\";\n"
 223                "\tlabel=\"loop %d\";\n"
 224                "\tlabeljust=l;\n"
 225                "\tpenwidth=2;\n",
 226                funcdef_no, loop->num,
 227                fillcolors[(loop_depth (loop) - 1) % 3],
 228                loop->num);
 229
 230   for (struct loop *inner = loop->inner; inner; inner = inner->next)
 231     draw_cfg_nodes_for_loop (pp, funcdef_no, inner);
 232
 233   if (loop->header == NULL)
 234     return;
 235
 236   if (loop->latch == EXIT_BLOCK_PTR)
 237     body = get_loop_body (loop);
 238   else
 239     body = get_loop_body_in_bfs_order (loop);
 240
 241   for (i = 0; i < loop->num_nodes; i++)
 242     {
 243       basic_block bb = body[i];
 244       if (bb->loop_father == loop)
 245         draw_cfg_node (pp, funcdef_no, bb);
 246     }
 247
 248   free (body);
 249
 250   if (loop->latch != EXIT_BLOCK_PTR)
 251     pp_printf (pp, "\t}\n");
 252 }
 253
 254 /* Draw all the basic blocks in the CFG in case the loop tree is available.
 255    All loop bodys are printed in clusters.  */
 256
 257 static void
 258 draw_cfg_nodes (pretty_printer *pp, struct function *fun)
 259 {
 260   /* ??? This x_current_loops should be enapsulated.  */
 261   if (fun->x_current_loops)
 262     draw_cfg_nodes_for_loop (pp, fun->funcdef_no,
 263                              fun->x_current_loops->tree_root);
 264   else
 265     draw_cfg_nodes_no_loops (pp, fun);
 266 }
 267
 268 /* Draw all edges in the CFG.  Retreating edges are drawin as not
 269    constraining, this makes the layout of the graph better.
 270    (??? Calling mark_dfs_back may change the compiler's behavior when
 271    dumping, but computing back edges here for ourselves is also not
 272    desirable.)  */
 273
 274 static void
 275 draw_cfg_edges (pretty_printer *pp, struct function *fun)
 276 {
 277   basic_block bb;
 278   mark_dfs_back_edges ();
 279   FOR_ALL_BB (bb)
 280     draw_cfg_node_succ_edges (pp, fun->funcdef_no, bb);
 281
 282   /* Add an invisible edge from ENTRY to EXIT, to improve the graph layout.  */
 283   pp_printf (pp,
 284              "\tfn_%d_basic_block_%d:s -> fn_%d_basic_block_%d:n "
 285              "[style=\"invis\",constraint=true];\n",
 286              fun->funcdef_no, ENTRY_BLOCK,
 287              fun->funcdef_no, EXIT_BLOCK);
 288   pp_flush (pp);
 289 }
 290
 291 /* Print a graphical representation of the CFG of function FUN.
 292    First print all basic blocks.  Draw all edges at the end to get
 293    subgraphs right for GraphViz, which requires nodes to be defined
 294    before edges to cluster nodes properly.  */
 295
 296 void
 297 print_graph_cfg (const char *base, struct function *fun)
 298 {
 299   const char *funcname = function_name (fun);
 300   FILE *fp = open_graph_file (base, "a");
 301   pretty_printer *pp = init_graph_slim_pretty_print (fp);
 302   pp_printf (pp, "subgraph \"%s\" {\n"
 303                  "\tcolor=\"black\";\n"
 304                  "\tlabel=\"%s\";\n",
 305                  funcname, funcname);
 306   draw_cfg_nodes (pp, fun);
 307   draw_cfg_edges (pp, fun);
 308   pp_printf (pp, "}\n");
 309   pp_flush (pp);
 310   fclose (fp);
 311 }
 312
 313 /* Start the dump of a graph.  */
 314 static void
 315 start_graph_dump (FILE *fp, const char *base)
 316 {
 317   pretty_printer *pp = init_graph_slim_pretty_print (fp);
 318   pp_string (pp, "digraph \"");
 319   pp_write_text_to_stream (pp);
 320   pp_string (pp, base);
 321   pp_write_text_as_dot_label_to_stream (pp, /*for_record=*/false);
 322   pp_string (pp, "\" {\n");
 323   pp_string (pp, "overlap=false;\n");
 324   pp_flush (pp);
 325 }
 326
 327 /* End the dump of a graph.  */
 328 static void
 329 end_graph_dump (FILE *fp)
 330 {
 331   fputs ("}\n", fp);
 332 }
 333
 334 /* Similar as clean_dump_file, but this time for graph output files.  */
 335 void
 336 clean_graph_dump_file (const char *base)
 337 {
 338   FILE *fp = open_graph_file (base, "w");
 339   start_graph_dump (fp, base);
 340   fclose (fp);
 341 }
 342
 343
 344 /* Do final work on the graph output file.  */
 345 void
 346 finish_graph_dump_file (const char *base)
 347 {
 348   FILE *fp = open_graph_file (base, "a");
 349   end_graph_dump (fp);
 350   fclose (fp);
 351 }