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 /* 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_core (struct obstack *oout, state *s)
  47 {
  48   item_number const *sitems = s->items;
  49   symbol *previous_lhs = NULL;
  50   size_t i;
  51   size_t snritems = s->nitems;
  52
  53   /* Output all the items of a state, not just its kernel.  */
  54   if (report_flag & report_itemsets)
  55     {
  56       closure (sitems, snritems);
  57       sitems = itemset;
  58       snritems = nitemset;
  59     }
  60
  61   obstack_printf (oout, _("State %d"), s->number);
  62   obstack_sgrow (oout, "\\n\\l");
  63   for (i = 0; i < snritems; i++)
  64     {
  65       item_number const *sp1 = ritem + sitems[i];
  66       item_number const *sp = sp1;
  67       rule *r;
  68
  69       while (0 <= *sp)
  70         sp++;
  71
  72       r = &rules[item_number_as_rule_number (*sp)];
  73
  74       obstack_printf (oout, "%3d ", r->number);
  75       if (previous_lhs && UNIQSTR_EQ (previous_lhs->tag, r->lhs->tag))
  76         obstack_printf (oout, "%*s| ",
  77                         (int) strlen (previous_lhs->tag), "");
  78       else
  79         obstack_printf (oout, "%s: ", escape (r->lhs->tag));
  80       previous_lhs = r->lhs;
  81
  82       for (sp = r->rhs; sp < sp1; sp++)
  83         obstack_printf (oout, "%s ", escape (symbols[*sp]->tag));
  84
  85       obstack_1grow (oout, '.');
  86
  87       for (/* Nothing */; *sp >= 0; ++sp)
  88         obstack_printf (oout, " %s", escape (symbols[*sp]->tag));
  89
  90       /* Experimental feature: display the lookahead tokens. */
  91       if (report_flag & report_lookahead_tokens
  92           && item_number_is_rule_number (*sp1))
  93         {
  94           /* Find the reduction we are handling.  */
  95           reductions *reds = s->reductions;
  96           int redno = state_reduction_find (s, r);
  97
  98           /* Print them if there are.  */
  99           if (reds->lookahead_tokens && redno != -1)
 100             {
 101               bitset_iterator biter;
 102               int k;
 103               char const *sep = "";
 104               obstack_sgrow (oout, "  [");
 105               BITSET_FOR_EACH (biter, reds->lookahead_tokens[redno], k, 0)
 106                 {
 107                   obstack_sgrow (oout, sep);
 108                   obstack_sgrow (oout, escape (symbols[k]->tag));
 109                   sep = ", ";
 110                 }
 111               obstack_1grow (oout, ']');
 112             }
 113         }
 114       obstack_sgrow (oout, "\\l");
 115     }
 116 }
 117
 118
 119 /*---------------------------------------------------------------.
 120 | Output in graph_obstack edges specifications in incidence with |
 121 | current node.                                                  |
 122 `---------------------------------------------------------------*/
 123
 124 static void
 125 print_actions (state const *s, FILE *fgraph)
 126 {
 127   transitions const *trans = s->transitions;
 128   int i;
 129
 130   if (!trans->num && !s->reductions)
 131     return;
 132
 133   for (i = 0; i < trans->num; i++)
 134     if (!TRANSITION_IS_DISABLED (trans, i))
 135       {
 136         state *s1 = trans->states[i];
 137         symbol_number sym = s1->accessing_symbol;
 138
 139         /* Shifts are solid, gotos are dashed, and error is dotted.  */
 140         char const *style =
 141           (TRANSITION_IS_ERROR (trans, i) ? "dotted"
 142            : TRANSITION_IS_SHIFT (trans, i) ? "solid"
 143            : "dashed");
 144
 145         if (TRANSITION_IS_ERROR (trans, i)
 146             && STRNEQ (symbols[sym]->tag, "error"))
 147           abort ();
 148         output_edge (s->number, s1->number,
 149                      TRANSITION_IS_ERROR (trans, i) ? NULL : symbols[sym]->tag,
 150                      style, fgraph);
 151       }
 152   /* Display reductions. */
 153   output_red (s, s->reductions, fgraph);
 154 }
 155
 156
 157 /*-------------------------------------------------------------.
 158 | Output in FGRAPH the current node specifications and exiting |
 159 | edges.                                                       |
 160 `-------------------------------------------------------------*/
 161
 162 static void
 163 print_state (state *s, FILE *fgraph)
 164 {
 165   struct obstack node_obstack;
 166
 167   /* A node's label contains its items.  */
 168   obstack_init (&node_obstack);
 169   print_core (&node_obstack, s);
 170   output_node (s->number, obstack_finish0 (&node_obstack), fgraph);
 171   obstack_free (&node_obstack, 0);
 172
 173   /* Output the edges.  */
 174   print_actions (s, fgraph);
 175 }
 176 \f
 177
 178 void
 179 print_graph (void)
 180 {
 181   state_number i;
 182   FILE *fgraph = xfopen (spec_graph_file, "w");
 183   start_graph (fgraph);
 184
 185   /* Output nodes and edges. */
 186   new_closure (nritems);
 187   for (i = 0; i < nstates; i++)
 188     print_state (states[i], fgraph);
 189   free_closure ();
 190
 191   finish_graph (fgraph);
 192   xfclose (fgraph);
 193 }