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 /* Print the lhs of a rule in such a manner that there is no vertical
  44    repetition, like in *.output files. */
  45
  46 static void
  47 print_lhs (struct obstack *oout, rule *previous_rule, rule *r)
  48 {
  49   if (previous_rule && STREQ (previous_rule->lhs->tag, r->lhs->tag))
  50     {
  51       int i;
  52       for (i = 0; i < strlen (r->lhs->tag); ++i)
  53         obstack_1grow (oout, ' ');
  54       obstack_1grow (oout, '|');
  55     }
  56   else
  57     {
  58       obstack_sgrow (oout, escape (r->lhs->tag));
  59       obstack_1grow (oout, ':');
  60     }
  61 }
  62
  63 static void
  64 print_core (struct obstack *oout, state *s)
  65 {
  66   item_number *sitems = s->items;
  67   rule *previous_rule = NULL;
  68   size_t i;
  69   size_t snritems = s->nitems;
  70
  71   /* Output all the items of a state, not only its kernel.  */
  72   if (report_flag & report_itemsets)
  73     {
  74       closure (sitems, snritems);
  75       sitems = itemset;
  76       snritems = nitemset;
  77     }
  78
  79   obstack_printf (oout, _("State %d"), s->number);
  80   obstack_sgrow (oout, "\\n");
  81   for (i = 0; i < snritems; i++)
  82     {
  83       item_number *sp;
  84       item_number *sp1;
  85       rule_number r;
  86
  87       sp1 = sp = ritem + sitems[i];
  88
  89       while (*sp >= 0)
  90         sp++;
  91
  92       r = item_number_as_rule_number (*sp);
  93
  94       obstack_printf (oout, "%3d ", r);
  95       print_lhs (oout, previous_rule, &rules[r]);
  96       previous_rule = &rules[r];
  97
  98       for (sp = rules[r].rhs; sp < sp1; sp++)
  99         obstack_printf (oout, " %s", escape (symbols[*sp]->tag));
 100
 101       obstack_sgrow (oout, " .");
 102
 103       for (/* Nothing */; *sp >= 0; ++sp)
 104         obstack_printf (oout, " %s", escape (symbols[*sp]->tag));
 105
 106       /* Experimental feature: display the lookahead tokens. */
 107       if (report_flag & report_lookahead_tokens
 108           && item_number_is_rule_number (*sp1))
 109         {
 110           /* Find the reduction we are handling.  */
 111           reductions *reds = s->reductions;
 112           int redno = state_reduction_find (s, &rules[r]);
 113
 114           /* Print them if there are.  */
 115           if (reds->lookahead_tokens && redno != -1)
 116             {
 117               bitset_iterator biter;
 118               int k;
 119               char const *sep = "";
 120               obstack_sgrow (oout, "  [");
 121               BITSET_FOR_EACH (biter, reds->lookahead_tokens[redno], k, 0)
 122                 {
 123                   obstack_sgrow (oout, sep);
 124                   obstack_sgrow (oout, escape (symbols[k]->tag));
 125                   sep = ", ";
 126                 }
 127               obstack_1grow (oout, ']');
 128             }
 129         }
 130       obstack_sgrow (oout, "\\l");
 131     }
 132 }
 133
 134
 135 /*---------------------------------------------------------------.
 136 | Output in graph_obstack edges specifications in incidence with |
 137 | current node.                                                  |
 138 `---------------------------------------------------------------*/
 139
 140 static void
 141 print_actions (state const *s, FILE *fgraph)
 142 {
 143   transitions const *trans = s->transitions;
 144   int i;
 145
 146   /* Display reductions. */
 147   output_red (s, s->reductions, fgraph);
 148
 149   if (!trans->num && !s->reductions)
 150     return;
 151
 152   for (i = 0; i < trans->num; i++)
 153     if (!TRANSITION_IS_DISABLED (trans, i))
 154       {
 155         state *s1 = trans->states[i];
 156         symbol_number sym = s1->accessing_symbol;
 157
 158         /* Shifts are solid, gotos are dashed, and error is dotted.  */
 159         char const *style =
 160           (TRANSITION_IS_ERROR (trans, i) ? "dotted"
 161            : TRANSITION_IS_SHIFT (trans, i) ? "solid"
 162            : "dashed");
 163
 164         if (TRANSITION_IS_ERROR (trans, i)
 165             && strcmp (symbols[sym]->tag, "error") != 0)
 166           abort ();
 167         output_edge (s->number, s1->number,
 168                      TRANSITION_IS_ERROR (trans, i) ? NULL : symbols[sym]->tag,
 169                      style, fgraph);
 170       }
 171 }
 172
 173
 174 /*-------------------------------------------------------------.
 175 | Output in FGRAPH the current node specifications and exiting |
 176 | edges.                                                       |
 177 `-------------------------------------------------------------*/
 178
 179 static void
 180 print_state (state *s, FILE *fgraph)
 181 {
 182   struct obstack node_obstack;
 183
 184   /* A node's label contains its items.  */
 185   obstack_init (&node_obstack);
 186   print_core (&node_obstack, s);
 187   obstack_1grow (&node_obstack, '\0');
 188   output_node (s->number, obstack_finish (&node_obstack), fgraph);
 189   obstack_free (&node_obstack, 0);
 190
 191   /* Output the edges.  */
 192   print_actions (s, fgraph);
 193 }
 194 \f
 195
 196 void
 197 print_graph (void)
 198 {
 199   state_number i;
 200   FILE *fgraph = xfopen (spec_graph_file, "w");
 201   start_graph (fgraph);
 202
 203   /* Output nodes and edges. */
 204   new_closure (nritems);
 205   for (i = 0; i < nstates; i++)
 206     print_state (states[i], fgraph);
 207   free_closure ();
 208
 209   finish_graph (fgraph);
 210   xfclose (fgraph);
 211 }