src/print_graph.c

   1 /* Output a graph of the generated parser, for Bison.
   2
   3    Copyright (C) 2001-2007, 2009-2015 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       if (0 <= *r->rhs)
  88         for (/* Nothing */; *sp >= 0; ++sp)
  89           obstack_printf (oout, " %s", escape (symbols[*sp]->tag));
  90       else
  91         obstack_printf (oout, " %%empty");
  92
  93       /* Experimental feature: display the lookahead tokens. */
  94       if (report_flag & report_lookahead_tokens
  95           && item_number_is_rule_number (*sp1))
  96         {
  97           /* Find the reduction we are handling.  */
  98           reductions *reds = s->reductions;
  99           int redno = state_reduction_find (s, r);
 100
 101           /* Print them if there are.  */
 102           if (reds->lookahead_tokens && redno != -1)
 103             {
 104               bitset_iterator biter;
 105               int k;
 106               char const *sep = "";
 107               obstack_sgrow (oout, "  [");
 108               BITSET_FOR_EACH (biter, reds->lookahead_tokens[redno], k, 0)
 109                 {
 110                   obstack_sgrow (oout, sep);
 111                   obstack_sgrow (oout, escape (symbols[k]->tag));
 112                   sep = ", ";
 113                 }
 114               obstack_1grow (oout, ']');
 115             }
 116         }
 117       obstack_sgrow (oout, "\\l");
 118     }
 119 }
 120
 121
 122 /*---------------------------------------------------------------.
 123 | Output in graph_obstack edges specifications in incidence with |
 124 | current node.                                                  |
 125 `---------------------------------------------------------------*/
 126
 127 static void
 128 print_actions (state const *s, FILE *fgraph)
 129 {
 130   transitions const *trans = s->transitions;
 131   int i;
 132
 133   if (!trans->num && !s->reductions)
 134     return;
 135
 136   for (i = 0; i < trans->num; i++)
 137     if (!TRANSITION_IS_DISABLED (trans, i))
 138       {
 139         state *s1 = trans->states[i];
 140         symbol_number sym = s1->accessing_symbol;
 141
 142         /* Shifts are solid, gotos are dashed, and error is dotted.  */
 143         char const *style =
 144           (TRANSITION_IS_ERROR (trans, i) ? "dotted"
 145            : TRANSITION_IS_SHIFT (trans, i) ? "solid"
 146            : "dashed");
 147
 148         if (TRANSITION_IS_ERROR (trans, i)
 149             && STRNEQ (symbols[sym]->tag, "error"))
 150           abort ();
 151         output_edge (s->number, s1->number,
 152                      TRANSITION_IS_ERROR (trans, i) ? NULL : symbols[sym]->tag,
 153                      style, fgraph);
 154       }
 155   /* Display reductions. */
 156   output_red (s, s->reductions, fgraph);
 157 }
 158
 159
 160 /*-------------------------------------------------------------.
 161 | Output in FGRAPH the current node specifications and exiting |
 162 | edges.                                                       |
 163 `-------------------------------------------------------------*/
 164
 165 static void
 166 print_state (state *s, FILE *fgraph)
 167 {
 168   struct obstack node_obstack;
 169
 170   /* A node's label contains its items.  */
 171   obstack_init (&node_obstack);
 172   print_core (&node_obstack, s);
 173   output_node (s->number, obstack_finish0 (&node_obstack), fgraph);
 174   obstack_free (&node_obstack, 0);
 175
 176   /* Output the edges.  */
 177   print_actions (s, fgraph);
 178 }
 179 \f
 180
 181 void
 182 print_graph (void)
 183 {
 184   state_number i;
 185   FILE *fgraph = xfopen (spec_graph_file, "w");
 186   start_graph (fgraph);
 187
 188   /* Output nodes and edges. */
 189   new_closure (nritems);
 190   for (i = 0; i < nstates; i++)
 191     print_state (states[i], fgraph);
 192   free_closure ();
 193
 194   finish_graph (fgraph);
 195   xfclose (fgraph);
 196 }