src/print_graph.c

   1 /* Output a graph of the generated parser, for Bison.
   2
   3    Copyright (C) 2001-2007, 2009-2012 Free Software Foundation, Inc.
   4
   5    This file is part of Bison, the GNU Compiler Compiler.
   6
   7    This program is free software: you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation, either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include <config.h>
  21 #include <quotearg.h>
  22 #include "system.h"
  23
  24 #include "LR0.h"
  25 #include "closure.h"
  26 #include "complain.h"
  27 #include "conflicts.h"
  28 #include "files.h"
  29 #include "getargs.h"
  30 #include "gram.h"
  31 #include "graphviz.h"
  32 #include "lalr.h"
  33 #include "print_graph.h"
  34 #include "reader.h"
  35 #include "state.h"
  36 #include "symtab.h"
  37
  38
  39 /*----------------------------.
  40 | Construct the node labels.  |
  41 `----------------------------*/
  42
  43 static void
  44 print_core (struct obstack *oout, state *s)
  45 {
  46   size_t i;
  47   item_number *sitems = s->items;
  48   size_t snritems = s->nitems;
  49
  50   /* Output all the items of a state, not only its kernel.  */
  51   if (report_flag & report_itemsets)
  52     {
  53       closure (sitems, snritems);
  54       sitems = itemset;
  55       snritems = nitemset;
  56     }
  57
  58   obstack_printf (oout, "state %d\\n", s->number);
  59   for (i = 0; i < snritems; i++)
  60     {
  61       item_number *sp;
  62       item_number *sp1;
  63       rule_number r;
  64
  65       sp1 = sp = ritem + sitems[i];
  66
  67       while (*sp >= 0)
  68         sp++;
  69
  70       r = item_number_as_rule_number (*sp);
  71
  72       obstack_printf (oout, "%d: %s -> ", r, escape (rules[r].lhs->tag));
  73
  74       for (sp = rules[r].rhs; sp < sp1; sp++)
  75         obstack_printf (oout, "%s ", escape (symbols[*sp]->tag));
  76
  77       obstack_1grow (oout, '.');
  78
  79       for (/* Nothing */; *sp >= 0; ++sp)
  80         obstack_printf (oout, " %s", escape (symbols[*sp]->tag));
  81
  82       /* Experimental feature: display the lookahead tokens. */
  83       if (report_flag & report_lookahead_tokens
  84           && item_number_is_rule_number (*sp1))
  85         {
  86           /* Find the reduction we are handling.  */
  87           reductions *reds = s->reductions;
  88           int redno = state_reduction_find (s, &rules[r]);
  89
  90           /* Print them if there are.  */
  91           if (reds->lookahead_tokens && redno != -1)
  92             {
  93               bitset_iterator biter;
  94               int k;
  95               char const *sep = "";
  96               obstack_1grow (oout, '[');
  97               BITSET_FOR_EACH (biter, reds->lookahead_tokens[redno], k, 0)
  98                 {
  99                   obstack_sgrow (oout, sep);
 100                   obstack_sgrow (oout, escape (symbols[k]->tag));
 101                   sep = ", ";
 102                 }
 103               obstack_1grow (oout, ']');
 104             }
 105         }
 106       obstack_sgrow (oout, "\\l");
 107     }
 108 }
 109
 110
 111 /*---------------------------------------------------------------.
 112 | Output in graph_obstack edges specifications in incidence with |
 113 | current node.                                                  |
 114 `---------------------------------------------------------------*/
 115
 116 static void
 117 print_actions (state const *s, FILE *fgraph)
 118 {
 119   int i;
 120
 121   transitions const *trans = s->transitions;
 122
 123   if (!trans->num && !s->reductions)
 124     return;
 125
 126   for (i = 0; i < trans->num; i++)
 127     if (!TRANSITION_IS_DISABLED (trans, i))
 128       {
 129         state *s1 = trans->states[i];
 130         symbol_number sym = s1->accessing_symbol;
 131
 132         /* Shifts are solid, gotos are dashed, and error is dotted.  */
 133         char const *style =
 134           (TRANSITION_IS_ERROR (trans, i) ? "dotted"
 135            : TRANSITION_IS_SHIFT (trans, i) ? "solid"
 136            : "dashed");
 137
 138         if (TRANSITION_IS_ERROR (trans, i)
 139             && strcmp (symbols[sym]->tag, "error") != 0)
 140           abort ();
 141         output_edge (s->number, s1->number,
 142                      TRANSITION_IS_ERROR (trans, i) ? NULL : symbols[sym]->tag,
 143                      style, fgraph);
 144       }
 145 }
 146
 147
 148 /*-------------------------------------------------------------.
 149 | Output in FGRAPH the current node specifications and exiting |
 150 | edges.                                                       |
 151 `-------------------------------------------------------------*/
 152
 153 static void
 154 print_state (state *s, FILE *fgraph)
 155 {
 156   struct obstack node_obstack;
 157
 158   /* A node's label contains its items.  */
 159   obstack_init (&node_obstack);
 160   print_core (&node_obstack, s);
 161   obstack_1grow (&node_obstack, '\0');
 162   output_node (s->number, obstack_finish (&node_obstack), fgraph);
 163   obstack_free (&node_obstack, 0);
 164
 165   /* Output the edges.  */
 166   print_actions (s, fgraph);
 167 }
 168 \f
 169
 170 void
 171 print_graph (void)
 172 {
 173   state_number i;
 174   FILE *fgraph = xfopen (spec_graph_file, "w");
 175   start_graph (fgraph);
 176
 177   /* Output nodes and edges. */
 178   new_closure (nritems);
 179   for (i = 0; i < nstates; i++)
 180     print_state (states[i], fgraph);
 181   free_closure ();
 182
 183   finish_graph (fgraph);
 184   xfclose (fgraph);
 185 }