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 "system.h"
  22
  23 #include "LR0.h"
  24 #include "closure.h"
  25 #include "complain.h"
  26 #include "conflicts.h"
  27 #include "files.h"
  28 #include "getargs.h"
  29 #include "gram.h"
  30 #include "graphviz.h"
  31 #include "lalr.h"
  32 #include "print_graph.h"
  33 #include "reader.h"
  34 #include "state.h"
  35 #include "symtab.h"
  36
  37
  38 /*----------------------------.
  39 | Construct the node labels.  |
  40 `----------------------------*/
  41
  42 static void
  43 print_core (struct obstack *oout, state *s)
  44 {
  45   size_t i;
  46   item_number *sitems = s->items;
  47   size_t snritems = s->nitems;
  48
  49   /* Output all the items of a state, not only its kernel.  */
  50   if (report_flag & report_itemsets)
  51     {
  52       closure (sitems, snritems);
  53       sitems = itemset;
  54       snritems = nitemset;
  55     }
  56
  57   obstack_fgrow1 (oout, "%d", s->number);
  58   for (i = 0; i < snritems; i++)
  59     {
  60       item_number *sp;
  61       item_number *sp1;
  62       rule_number r;
  63
  64       sp1 = sp = ritem + sitems[i];
  65
  66       while (*sp >= 0)
  67         sp++;
  68
  69       r = item_number_as_rule_number (*sp);
  70
  71       obstack_fgrow1 (oout, "\n%s -> ", rules[r].lhs->tag);
  72
  73       for (sp = rules[r].rhs; sp < sp1; sp++)
  74         obstack_fgrow1 (oout, "%s ", symbols[*sp]->tag);
  75
  76       obstack_1grow (oout, '.');
  77
  78       for (/* Nothing */; *sp >= 0; ++sp)
  79         obstack_fgrow1 (oout, " %s", symbols[*sp]->tag);
  80
  81       /* Experimental feature: display the lookahead tokens. */
  82       if (report_flag & report_lookahead_tokens
  83           && item_number_is_rule_number (*sp1))
  84         {
  85           /* Find the reduction we are handling.  */
  86           reductions *reds = s->reductions;
  87           int redno = state_reduction_find (s, &rules[r]);
  88
  89           /* Print them if there are.  */
  90           if (reds->lookahead_tokens && redno != -1)
  91             {
  92               bitset_iterator biter;
  93               int k;
  94               char const *sep = "";
  95               obstack_sgrow (oout, "[");
  96               BITSET_FOR_EACH (biter, reds->lookahead_tokens[redno], k, 0)
  97                 {
  98                   obstack_fgrow2 (oout, "%s%s", sep, symbols[k]->tag);
  99                   sep = ", ";
 100                 }
 101               obstack_sgrow (oout, "]");
 102             }
 103         }
 104     }
 105 }
 106
 107
 108 /*---------------------------------------------------------------.
 109 | Output in graph_obstack edges specifications in incidence with |
 110 | current node.                                                  |
 111 `---------------------------------------------------------------*/
 112
 113 static void
 114 print_actions (state const *s, FILE *fgraph)
 115 {
 116   int i;
 117
 118   transitions const *trans = s->transitions;
 119
 120   if (!trans->num && !s->reductions)
 121     return;
 122
 123   for (i = 0; i < trans->num; i++)
 124     if (!TRANSITION_IS_DISABLED (trans, i))
 125       {
 126         state *s1 = trans->states[i];
 127         symbol_number sym = s1->accessing_symbol;
 128
 129         /* Shifts are solid, gotos are dashed, and error is dotted.  */
 130         char const *style =
 131           (TRANSITION_IS_ERROR (trans, i) ? "dotted"
 132            : TRANSITION_IS_SHIFT (trans, i) ? "solid"
 133            : "dashed");
 134
 135         if (TRANSITION_IS_ERROR (trans, i)
 136             && strcmp (symbols[sym]->tag, "error") != 0)
 137           abort ();
 138         output_edge (s->number, s1->number,
 139                      TRANSITION_IS_ERROR (trans, i) ? NULL : symbols[sym]->tag,
 140                      style, fgraph);
 141       }
 142 }
 143
 144
 145 /*-------------------------------------------------------------.
 146 | Output in FGRAPH the current node specifications and exiting |
 147 | edges.                                                       |
 148 `-------------------------------------------------------------*/
 149
 150 static void
 151 print_state (state *s, FILE *fgraph)
 152 {
 153   struct obstack node_obstack;
 154
 155   /* A node's label contains its items.  */
 156   obstack_init (&node_obstack);
 157   print_core (&node_obstack, s);
 158   obstack_1grow (&node_obstack, '\0');
 159   output_node (s->number, obstack_finish (&node_obstack), fgraph);
 160   obstack_free (&node_obstack, 0);
 161
 162   /* Output the edges.  */
 163   print_actions (s, fgraph);
 164 }
 165 \f
 166
 167 void
 168 print_graph (void)
 169 {
 170   state_number i;
 171   FILE *fgraph = xfopen (spec_graph_file, "w");
 172   start_graph (fgraph);
 173
 174   /* Output nodes and edges. */
 175   new_closure (nritems);
 176   for (i = 0; i < nstates; i++)
 177     print_state (states[i], fgraph);
 178   free_closure ();
 179
 180   finish_graph (fgraph);
 181   xfclose (fgraph);
 182 }