gcc-4_8/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, label=\"[%i%%]\"];\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                  e->probability * 100 / REG_BR_PROB_BASE);
 164     }
 165   pp_flush (pp);
 166 }
 167
 168 /* Draw all the basic blocks in the CFG in case loops are not available.
 169    First compute a topological order of the blocks to get a good ranking of
 170    the nodes.  Then, if any nodes are not reachable from ENTRY, add them at
 171    the end.  */
 172
 173 static void
 174 draw_cfg_nodes_no_loops (pretty_printer *pp, struct function *fun)
 175 {
 176   int *rpo = XNEWVEC (int, n_basic_blocks_for_function (fun));
 177   int i, n;
 178   sbitmap visited;
 179
 180   visited = sbitmap_alloc (last_basic_block);
 181   bitmap_clear (visited);
 182
 183   /* FIXME: pre_and_rev_post_order_compute only works if fun == cfun.  */
 184   n = pre_and_rev_post_order_compute (NULL, rpo, true);
 185   for (i = 0; i < n; i++)
 186     {
 187       basic_block bb = BASIC_BLOCK (rpo[i]);
 188       draw_cfg_node (pp, fun->funcdef_no, bb);
 189       bitmap_set_bit (visited, bb->index);
 190     }
 191   free (rpo);
 192
 193   if (n != n_basic_blocks_for_function (fun))
 194     {
 195       /* Some blocks are unreachable.  We still want to dump them.  */
 196       basic_block bb;
 197       FOR_ALL_BB_FN (bb, fun)
 198         if (! bitmap_bit_p (visited, bb->index))
 199           draw_cfg_node (pp, fun->funcdef_no, bb);
 200     }
 201
 202   sbitmap_free (visited);
 203 }
 204
 205 /* Draw all the basic blocks in LOOP.  Print the blocks in breath-first
 206    order to get a good ranking of the nodes.  This function is recursive:
 207    It first prints inner loops, then the body of LOOP itself.  */
 208
 209 static void
 210 draw_cfg_nodes_for_loop (pretty_printer *pp, int funcdef_no,
 211                          struct loop *loop)
 212 {
 213   basic_block *body;
 214   unsigned int i;
 215   const char *fillcolors[3] = { "grey88", "grey77", "grey66" };
 216
 217   if (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->latch == EXIT_BLOCK_PTR)
 234     body = get_loop_body (loop);
 235   else
 236     body = get_loop_body_in_bfs_order (loop);
 237
 238   for (i = 0; i < loop->num_nodes; i++)
 239     {
 240       basic_block bb = body[i];
 241       if (bb->loop_father == loop)
 242         draw_cfg_node (pp, funcdef_no, bb);
 243     }
 244
 245   free (body);
 246
 247   if (loop->latch != EXIT_BLOCK_PTR)
 248     pp_printf (pp, "\t}\n");
 249 }
 250
 251 /* Draw all the basic blocks in the CFG in case the loop tree is available.
 252    All loop bodys are printed in clusters.  */
 253
 254 static void
 255 draw_cfg_nodes (pretty_printer *pp, struct function *fun)
 256 {
 257   /* ??? This x_current_loops should be enapsulated.  */
 258   if (fun->x_current_loops)
 259     draw_cfg_nodes_for_loop (pp, fun->funcdef_no,
 260                              fun->x_current_loops->tree_root);
 261   else
 262     draw_cfg_nodes_no_loops (pp, fun);
 263 }
 264
 265 /* Draw all edges in the CFG.  Retreating edges are drawin as not
 266    constraining, this makes the layout of the graph better.
 267    (??? Calling mark_dfs_back may change the compiler's behavior when
 268    dumping, but computing back edges here for ourselves is also not
 269    desirable.)  */
 270
 271 static void
 272 draw_cfg_edges (pretty_printer *pp, struct function *fun)
 273 {
 274   basic_block bb;
 275   mark_dfs_back_edges ();
 276   FOR_ALL_BB (bb)
 277     draw_cfg_node_succ_edges (pp, fun->funcdef_no, bb);
 278
 279   /* Add an invisible edge from ENTRY to EXIT, to improve the graph layout.  */
 280   pp_printf (pp,
 281              "\tfn_%d_basic_block_%d:s -> fn_%d_basic_block_%d:n "
 282              "[style=\"invis\",constraint=true];\n",
 283              fun->funcdef_no, ENTRY_BLOCK,
 284              fun->funcdef_no, EXIT_BLOCK);
 285   pp_flush (pp);
 286 }
 287
 288 /* Print a graphical representation of the CFG of function FUN.
 289    First print all basic blocks.  Draw all edges at the end to get
 290    subgraphs right for GraphViz, which requires nodes to be defined
 291    before edges to cluster nodes properly.  */
 292
 293 void
 294 print_graph_cfg (const char *base, struct function *fun)
 295 {
 296   const char *funcname = function_name (fun);
 297   FILE *fp = open_graph_file (base, "a");
 298   pretty_printer *pp = init_graph_slim_pretty_print (fp);
 299   pp_printf (pp, "subgraph \"%s\" {\n"
 300                  "\tcolor=\"black\";\n"
 301                  "\tlabel=\"%s\";\n",
 302                  funcname, funcname);
 303   draw_cfg_nodes (pp, fun);
 304   draw_cfg_edges (pp, fun);
 305   pp_printf (pp, "}\n");
 306   pp_flush (pp);
 307   fclose (fp);
 308 }
 309
 310 /* Start the dump of a graph.  */
 311 static void
 312 start_graph_dump (FILE *fp, const char *base)
 313 {
 314   pretty_printer *pp = init_graph_slim_pretty_print (fp);
 315   pp_string (pp, "digraph \"");
 316   pp_write_text_to_stream (pp);
 317   pp_string (pp, base);
 318   pp_write_text_as_dot_label_to_stream (pp, /*for_record=*/false);
 319   pp_string (pp, "\" {\n");
 320   pp_string (pp, "overlap=false;\n");
 321   pp_flush (pp);
 322 }
 323
 324 /* End the dump of a graph.  */
 325 static void
 326 end_graph_dump (FILE *fp)
 327 {
 328   fputs ("}\n", fp);
 329 }
 330
 331 /* Similar as clean_dump_file, but this time for graph output files.  */
 332 void
 333 clean_graph_dump_file (const char *base)
 334 {
 335   FILE *fp = open_graph_file (base, "w");
 336   start_graph_dump (fp, base);
 337   fclose (fp);
 338 }
 339
 340
 341 /* Do final work on the graph output file.  */
 342 void
 343 finish_graph_dump_file (const char *base)
 344 {
 345   FILE *fp = open_graph_file (base, "a");
 346   end_graph_dump (fp);
 347   fclose (fp);
 348 }