src/derives.c

   1 /* Match rules with nonterminals for bison,
   2    Copyright 1984, 1989, 2000, 2001  Free Software Foundation, Inc.
   3
   4    This file is part of Bison, the GNU Compiler Compiler.
   5
   6    Bison is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2, or (at your option)
   9    any later version.
  10
  11    Bison is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with Bison; see the file COPYING.  If not, write to
  18    the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  19    Boston, MA 02111-1307, USA.  */
  20
  21
  22 #include "system.h"
  23 #include "getargs.h"
  24 #include "types.h"
  25 #include "reader.h"
  26 #include "gram.h"
  27 #include "derives.h"
  28
  29 short **derives = NULL;
  30
  31 static void
  32 print_derives (void)
  33 {
  34   int i;
  35
  36   fputs ("DERIVES\n", stderr);
  37
  38   for (i = ntokens; i < nsyms; i++)
  39     {
  40       short *sp;
  41       fprintf (stderr, "\t%s derives\n", tags[i]);
  42       for (sp = derives[i]; *sp > 0; sp++)
  43         {
  44           short *rhsp;
  45           fprintf (stderr, "\t\t%d:", *sp);
  46           for (rhsp = &ritem[rule_table[*sp].rhs]; *rhsp >= 0; ++rhsp)
  47             fprintf (stderr, " %s", tags[*rhsp]);
  48           fprintf (stderr, " (rule %d)\n", -*rhsp - 1);
  49         }
  50     }
  51
  52   fputs ("\n\n", stderr);
  53 }
  54
  55
  56 void
  57 set_derives (void)
  58 {
  59   int i;
  60   shorts *p;
  61   short *q;
  62   shorts **dset;
  63   shorts *delts;
  64
  65   dset = XCALLOC (shorts *, nvars) - ntokens;
  66   delts = XCALLOC (shorts, nrules + 1);
  67
  68   p = delts;
  69   for (i = nrules; i > 0; i--)
  70     if (rule_table[i].useful)
  71       {
  72         int lhs = rule_table[i].lhs;
  73         p->next = dset[lhs];
  74         p->value = i;
  75         dset[lhs] = p;
  76         p++;
  77       }
  78
  79   derives = XCALLOC (short *, nvars) - ntokens;
  80   q = XCALLOC (short, nvars + nrules);
  81
  82   for (i = ntokens; i < nsyms; i++)
  83     {
  84       derives[i] = q;
  85       p = dset[i];
  86       while (p)
  87         {
  88           *q++ = p->value;
  89           p = p->next;
  90         }
  91       *q++ = -1;
  92     }
  93
  94   if (trace_flag)
  95     print_derives ();
  96
  97   XFREE (dset + ntokens);
  98   XFREE (delts);
  99 }
 100
 101 void
 102 free_derives (void)
 103 {
 104   XFREE (derives[ntokens]);
 105   XFREE (derives + ntokens);
 106 }