src/print_graph.c

   1 /* Output a graph of the generated parser, for Bison.
   2
   3    Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007 Free Software
   4    Foundation, Inc.
   5
   6    This file is part of Bison, the GNU Compiler Compiler.
   7
   8    This program is free software: you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation, either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 #include <config.h>
  22 #include "system.h"
  23
  24 #include <quotearg.h>
  25
  26 #include "LR0.h"
  27 #include "closure.h"
  28 #include "complain.h"
  29 #include "conflicts.h"
  30 #include "files.h"
  31 #include "getargs.h"
  32 #include "gram.h"
  33 #include "graphviz.h"
  34 #include "lalr.h"
  35 #include "print_graph.h"
  36 #include "reader.h"
  37 #include "state.h"
  38 #include "symtab.h"
  39
  40
  41 /*----------------------------.
  42 | Construct the node labels.  |
  43 `----------------------------*/
  44
  45 static void
  46 print_core (struct obstack *oout, state *s)
  47 {
  48   size_t i;
  49   item_number *sitems = s->items;
  50   size_t snritems = s->nitems;
  51
  52   /* Output all the items of a state, not only its kernel.  */
  53   if (report_flag & report_itemsets)
  54     {
  55       closure (sitems, snritems);
  56       sitems = itemset;
  57       snritems = nitemset;
  58     }
  59
  60   obstack_fgrow1 (oout, "%d", s->number);
  61   for (i = 0; i < snritems; i++)
  62     {
  63       item_number *sp;
  64       item_number *sp1;
  65       rule_number r;
  66
  67       sp1 = sp = ritem + sitems[i];
  68
  69       while (*sp >= 0)
  70         sp++;
  71
  72       r = item_number_as_rule_number (*sp);
  73
  74       obstack_fgrow1 (oout, "\n%s -> ", rules[r].lhs->tag);
  75
  76       for (sp = rules[r].rhs; sp < sp1; sp++)
  77         obstack_fgrow1 (oout, "%s ", symbols[*sp]->tag);
  78
  79       obstack_1grow (oout, '.');
  80
  81       for (/* Nothing */; *sp >= 0; ++sp)
  82         obstack_fgrow1 (oout, " %s", symbols[*sp]->tag);
  83
  84       /* Experimental feature: display the lookahead tokens. */
  85       if (report_flag & report_lookahead_tokens
  86           && item_number_is_rule_number (*sp1))
  87         {
  88           /* Find the reduction we are handling.  */
  89           reductions *reds = s->reductions;
  90           int redno = state_reduction_find (s, &rules[r]);
  91
  92           /* Print them if there are.  */
  93           if (reds->lookahead_tokens && redno != -1)
  94             {
  95               bitset_iterator biter;
  96               int k;
  97               char const *sep = "";
  98               obstack_sgrow (oout, "[");
  99               BITSET_FOR_EACH (biter, reds->lookahead_tokens[redno], k, 0)
 100                 {
 101                   obstack_fgrow2 (oout, "%s%s", sep, symbols[k]->tag);
 102                   sep = ", ";
 103                 }
 104               obstack_sgrow (oout, "]");
 105             }
 106         }
 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 }