src/print_graph.c

   1 /* Output a graph of the generated parser, for Bison.
   2
   3    Copyright (C) 2001-2007, 2009-2013 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 /* Print the lhs of a rule in such a manner that there is no vertical
  43    repetition, like in *.output files. */
  44
  45 static void
  46 print_lhs (struct obstack *oout, rule *previous_rule, rule *r)
  47 {
  48   if (previous_rule && STREQ (previous_rule->lhs->tag, r->lhs->tag))
  49     {
  50       int i;
  51       for (i = 0; i < strlen (r->lhs->tag); ++i)
  52         obstack_1grow (oout, ' ');
  53       obstack_1grow (oout, '|');
  54     }
  55   else
  56     {
  57       obstack_sgrow (oout, escape (r->lhs->tag));
  58       obstack_1grow (oout, ':');
  59     }
  60 }
  61
  62 static void
  63 print_core (struct obstack *oout, state *s)
  64 {
  65   item_number *sitems = s->items;
  66   rule *previous_rule = NULL;
  67   size_t i;
  68   size_t snritems = s->nitems;
  69
  70   /* Output all the items of a state, not only its kernel.  */
  71   if (report_flag & report_itemsets)
  72     {
  73       closure (sitems, snritems);
  74       sitems = itemset;
  75       snritems = nitemset;
  76     }
  77
  78   obstack_printf (oout, _("State %d"), s->number);
  79   obstack_sgrow (oout, "\\n\\l");
  80   for (i = 0; i < snritems; i++)
  81     {
  82       item_number *sp;
  83       item_number *sp1;
  84       rule_number r;
  85
  86       sp1 = sp = ritem + sitems[i];
  87
  88       while (*sp >= 0)
  89         sp++;
  90
  91       r = item_number_as_rule_number (*sp);
  92
  93       obstack_printf (oout, "%3d ", r);
  94       print_lhs (oout, previous_rule, &rules[r]);
  95       previous_rule = &rules[r];
  96
  97       for (sp = rules[r].rhs; sp < sp1; sp++)
  98         obstack_printf (oout, " %s", escape (symbols[*sp]->tag));
  99
 100       obstack_sgrow (oout, " .");
 101
 102       for (/* Nothing */; *sp >= 0; ++sp)
 103         obstack_printf (oout, " %s", escape (symbols[*sp]->tag));
 104
 105       /* Experimental feature: display the lookahead tokens. */
 106       if (report_flag & report_lookahead_tokens
 107           && item_number_is_rule_number (*sp1))
 108         {
 109           /* Find the reduction we are handling.  */
 110           reductions *reds = s->reductions;
 111           int redno = state_reduction_find (s, &rules[r]);
 112
 113           /* Print them if there are.  */
 114           if (reds->lookahead_tokens && redno != -1)
 115             {
 116               bitset_iterator biter;
 117               int k;
 118               char const *sep = "";
 119               obstack_sgrow (oout, "  [");
 120               BITSET_FOR_EACH (biter, reds->lookahead_tokens[redno], k, 0)
 121                 {
 122                   obstack_sgrow (oout, sep);
 123                   obstack_sgrow (oout, escape (symbols[k]->tag));
 124                   sep = ", ";
 125                 }
 126               obstack_1grow (oout, ']');
 127             }
 128         }
 129       obstack_sgrow (oout, "\\l");
 130     }
 131 }
 132
 133
 134 /*---------------------------------------------------------------.
 135 | Output in graph_obstack edges specifications in incidence with |
 136 | current node.                                                  |
 137 `---------------------------------------------------------------*/
 138
 139 static void
 140 print_actions (state const *s, FILE *fgraph)
 141 {
 142   transitions const *trans = s->transitions;
 143   int i;
 144
 145   if (!trans->num && !s->reductions)
 146     return;
 147
 148   for (i = 0; i < trans->num; i++)
 149     if (!TRANSITION_IS_DISABLED (trans, i))
 150       {
 151         state *s1 = trans->states[i];
 152         symbol_number sym = s1->accessing_symbol;
 153
 154         /* Shifts are solid, gotos are dashed, and error is dotted.  */
 155         char const *style =
 156           (TRANSITION_IS_ERROR (trans, i) ? "dotted"
 157            : TRANSITION_IS_SHIFT (trans, i) ? "solid"
 158            : "dashed");
 159
 160         if (TRANSITION_IS_ERROR (trans, i)
 161             && strcmp (symbols[sym]->tag, "error") != 0)
 162           abort ();
 163         output_edge (s->number, s1->number,
 164                      TRANSITION_IS_ERROR (trans, i) ? NULL : symbols[sym]->tag,
 165                      style, fgraph);
 166       }
 167   /* Display reductions. */
 168   output_red (s, s->reductions, fgraph);
 169 }
 170
 171
 172 /*-------------------------------------------------------------.
 173 | Output in FGRAPH the current node specifications and exiting |
 174 | edges.                                                       |
 175 `-------------------------------------------------------------*/
 176
 177 static void
 178 print_state (state *s, FILE *fgraph)
 179 {
 180   struct obstack node_obstack;
 181
 182   /* A node's label contains its items.  */
 183   obstack_init (&node_obstack);
 184   print_core (&node_obstack, s);
 185   obstack_1grow (&node_obstack, '\0');
 186   output_node (s->number, obstack_finish (&node_obstack), fgraph);
 187   obstack_free (&node_obstack, 0);
 188
 189   /* Output the edges.  */
 190   print_actions (s, fgraph);
 191 }
 192 \f
 193
 194 void
 195 print_graph (void)
 196 {
 197   state_number i;
 198   FILE *fgraph = xfopen (spec_graph_file, "w");
 199   start_graph (fgraph);
 200
 201   /* Output nodes and edges. */
 202   new_closure (nritems);
 203   for (i = 0; i < nstates; i++)
 204     print_state (states[i], fgraph);
 205   free_closure ();
 206
 207   finish_graph (fgraph);
 208   xfclose (fgraph);
 209 }