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 <quotearg.h>
  24
  25 #include "LR0.h"
  26 #include "closure.h"
  27 #include "complain.h"
  28 #include "conflicts.h"
  29 #include "files.h"
  30 #include "getargs.h"
  31 #include "gram.h"
  32 #include "graphviz.h"
  33 #include "lalr.h"
  34 #include "print_graph.h"
  35 #include "reader.h"
  36 #include "state.h"
  37 #include "symtab.h"
  38
  39
  40 /*----------------------------.
  41 | Construct the node labels.  |
  42 `----------------------------*/
  43
  44 static void
  45 print_core (struct obstack *oout, state *s)
  46 {
  47   size_t i;
  48   item_number *sitems = s->items;
  49   size_t snritems = s->nitems;
  50
  51   /* Output all the items of a state, not only its kernel.  */
  52   if (report_flag & report_itemsets)
  53     {
  54       closure (sitems, snritems);
  55       sitems = itemset;
  56       snritems = nitemset;
  57     }
  58
  59   obstack_fgrow1 (oout, "%d", s->number);
  60   for (i = 0; i < snritems; i++)
  61     {
  62       item_number *sp;
  63       item_number *sp1;
  64       rule_number r;
  65
  66       sp1 = sp = ritem + sitems[i];
  67
  68       while (*sp >= 0)
  69         sp++;
  70
  71       r = item_number_as_rule_number (*sp);
  72
  73       obstack_fgrow1 (oout, "\n%s -> ", rules[r].lhs->tag);
  74
  75       for (sp = rules[r].rhs; sp < sp1; sp++)
  76         obstack_fgrow1 (oout, "%s ", symbols[*sp]->tag);
  77
  78       obstack_1grow (oout, '.');
  79
  80       for (/* Nothing */; *sp >= 0; ++sp)
  81         obstack_fgrow1 (oout, " %s", symbols[*sp]->tag);
  82
  83       /* Experimental feature: display the lookahead tokens. */
  84       if (report_flag & report_lookahead_tokens
  85           && item_number_is_rule_number (*sp1))
  86         {
  87           /* Find the reduction we are handling.  */
  88           reductions *reds = s->reductions;
  89           int redno = state_reduction_find (s, &rules[r]);
  90
  91           /* Print them if there are.  */
  92           if (reds->lookahead_tokens && redno != -1)
  93             {
  94               bitset_iterator biter;
  95               int k;
  96               char const *sep = "";
  97               obstack_sgrow (oout, "[");
  98               BITSET_FOR_EACH (biter, reds->lookahead_tokens[redno], k, 0)
  99                 {
 100                   obstack_fgrow2 (oout, "%s%s", sep, symbols[k]->tag);
 101                   sep = ", ";
 102                 }
 103               obstack_sgrow (oout, "]");
 104             }
 105         }
 106     }
 107 }
 108
 109
 110 /*---------------------------------------------------------------.
 111 | Output in graph_obstack edges specifications in incidence with |
 112 | current node.                                                  |
 113 `---------------------------------------------------------------*/
 114
 115 static void
 116 print_actions (state const *s, FILE *fgraph)
 117 {
 118   int i;
 119
 120   transitions const *trans = s->transitions;
 121
 122   if (!trans->num && !s->reductions)
 123     return;
 124
 125   for (i = 0; i < trans->num; i++)
 126     if (!TRANSITION_IS_DISABLED (trans, i))
 127       {
 128         state *s1 = trans->states[i];
 129         symbol_number sym = s1->accessing_symbol;
 130
 131         /* Shifts are solid, gotos are dashed, and error is dotted.  */
 132         char const *style =
 133           (TRANSITION_IS_ERROR (trans, i) ? "dotted"
 134            : TRANSITION_IS_SHIFT (trans, i) ? "solid"
 135            : "dashed");
 136
 137         if (TRANSITION_IS_ERROR (trans, i)
 138             && strcmp (symbols[sym]->tag, "error") != 0)
 139           abort ();
 140         output_edge (s->number, s1->number,
 141                      TRANSITION_IS_ERROR (trans, i) ? NULL : symbols[sym]->tag,
 142                      style, fgraph);
 143       }
 144 }
 145
 146
 147 /*-------------------------------------------------------------.
 148 | Output in FGRAPH the current node specifications and exiting |
 149 | edges.                                                       |
 150 `-------------------------------------------------------------*/
 151
 152 static void
 153 print_state (state *s, FILE *fgraph)
 154 {
 155   struct obstack node_obstack;
 156
 157   /* A node's label contains its items.  */
 158   obstack_init (&node_obstack);
 159   print_core (&node_obstack, s);
 160   obstack_1grow (&node_obstack, '\0');
 161   output_node (s->number, obstack_finish (&node_obstack), fgraph);
 162   obstack_free (&node_obstack, 0);
 163
 164   /* Output the edges.  */
 165   print_actions (s, fgraph);
 166 }
 167 \f
 168
 169 void
 170 print_graph (void)
 171 {
 172   state_number i;
 173   FILE *fgraph = xfopen (spec_graph_file, "w");
 174   start_graph (fgraph);
 175
 176   /* Output nodes and edges. */
 177   new_closure (nritems);
 178   for (i = 0; i < nstates; i++)
 179     print_state (states[i], fgraph);
 180   free_closure ();
 181
 182   finish_graph (fgraph);
 183   xfclose (fgraph);
 184 }