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   obstack_1grow (oout, ' ');
  62 }
  63
  64 static void
  65 print_core (struct obstack *oout, state *s)
  66 {
  67   item_number *sitems = s->items;
  68   rule *previous_rule = NULL;
  69   size_t i;
  70   size_t snritems = s->nitems;
  71
  72   /* Output all the items of a state, not only its kernel.  */
  73   if (report_flag & report_itemsets)
  74     {
  75       closure (sitems, snritems);
  76       sitems = itemset;
  77       snritems = nitemset;
  78     }
  79
  80   obstack_printf (oout, _("State %d"), s->number);
  81   obstack_sgrow (oout, "\\n");
  82   for (i = 0; i < snritems; i++)
  83     {
  84       item_number *sp;
  85       item_number *sp1;
  86       rule_number r;
  87
  88       sp1 = sp = ritem + sitems[i];
  89
  90       while (*sp >= 0)
  91         sp++;
  92
  93       r = item_number_as_rule_number (*sp);
  94
  95       obstack_printf (oout, "%3d ", r);
  96       print_lhs (oout, previous_rule, &rules[r]);
  97       previous_rule = &rules[r];
  98
  99       for (sp = rules[r].rhs; sp < sp1; sp++)
 100         obstack_printf (oout, "%s ", escape (symbols[*sp]->tag));
 101
 102       obstack_1grow (oout, '.');
 103
 104       for (/* Nothing */; *sp >= 0; ++sp)
 105         obstack_printf (oout, " %s", escape (symbols[*sp]->tag));
 106
 107       /* Experimental feature: display the lookahead tokens. */
 108       if (report_flag & report_lookahead_tokens
 109           && item_number_is_rule_number (*sp1))
 110         {
 111           /* Find the reduction we are handling.  */
 112           reductions *reds = s->reductions;
 113           int redno = state_reduction_find (s, &rules[r]);
 114
 115           /* Print them if there are.  */
 116           if (reds->lookahead_tokens && redno != -1)
 117             {
 118               bitset_iterator biter;
 119               int k;
 120               char const *sep = "";
 121               obstack_sgrow (oout, "  [");
 122               BITSET_FOR_EACH (biter, reds->lookahead_tokens[redno], k, 0)
 123                 {
 124                   obstack_sgrow (oout, sep);
 125                   obstack_sgrow (oout, escape (symbols[k]->tag));
 126                   sep = ", ";
 127                 }
 128               obstack_1grow (oout, ']');
 129             }
 130         }
 131       obstack_sgrow (oout, "\\l");
 132     }
 133 }
 134
 135
 136 /*---------------------------------------------------------------.
 137 | Output in graph_obstack edges specifications in incidence with |
 138 | current node.                                                  |
 139 `---------------------------------------------------------------*/
 140
 141 static void
 142 print_actions (state const *s, FILE *fgraph)
 143 {
 144   transitions const *trans = s->transitions;
 145   int i;
 146
 147   /* Display reductions. */
 148   output_red (s, s->reductions, fgraph);
 149
 150   if (!trans->num && !s->reductions)
 151     return;
 152
 153   for (i = 0; i < trans->num; i++)
 154     if (!TRANSITION_IS_DISABLED (trans, i))
 155       {
 156         state *s1 = trans->states[i];
 157         symbol_number sym = s1->accessing_symbol;
 158
 159         /* Shifts are solid, gotos are dashed, and error is dotted.  */
 160         char const *style =
 161           (TRANSITION_IS_ERROR (trans, i) ? "dotted"
 162            : TRANSITION_IS_SHIFT (trans, i) ? "solid"
 163            : "dashed");
 164
 165         if (TRANSITION_IS_ERROR (trans, i)
 166             && STRNEQ (symbols[sym]->tag, "error"))
 167           abort ();
 168         output_edge (s->number, s1->number,
 169                      TRANSITION_IS_ERROR (trans, i) ? NULL : symbols[sym]->tag,
 170                      style, fgraph);
 171       }
 172 }
 173
 174
 175 /*-------------------------------------------------------------.
 176 | Output in FGRAPH the current node specifications and exiting |
 177 | edges.                                                       |
 178 `-------------------------------------------------------------*/
 179
 180 static void
 181 print_state (state *s, FILE *fgraph)
 182 {
 183   struct obstack node_obstack;
 184
 185   /* A node's label contains its items.  */
 186   obstack_init (&node_obstack);
 187   print_core (&node_obstack, s);
 188   output_node (s->number, obstack_finish0 (&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 }