Do not let the scan-skel token buffer grow unboundedly in the usual case.

[bison.git] / src / derives.c

diff --git a/src/derives.c b/src/derives.c
index 6a5681bb35af7fdff7e779287965290f2a86bcc5..da881ecc521e8277974e22adcb88a24c6c39b94b 100644 (file)
--- a/src/derives.c
+++ b/src/derives.c
@@ -1,5 +1,7 @@
 /* Match rules with nonterminals for bison,
-   Copyright 1984, 1989, 2000, 2001, 2002  Free Software Foundation, Inc.
+
+   Copyright (C) 1984, 1989, 2000, 2001, 2002 Free Software
+   Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
@@ -20,14 +22,22 @@
 
 
 #include "system.h"
+
 #include "getargs.h"
-#include "symtab.h"
-#include "types.h"
-#include "reader.h"
-#include "gram.h"
+
 #include "derives.h"
+#include "gram.h"
+#include "reader.h"
+#include "symtab.h"
+
+/* Linked list of rule numbers.  */
+typedef struct rule_list
+{
+  struct rule_list *next;
+  rule *value;
+} rule_list;
 
-rule_number_t **derives = NULL;
+rule ***derives = NULL;
 
 static void
 print_derives (void)
@@ -38,16 +48,12 @@ print_derives (void)
 
   for (i = ntokens; i < nsyms; i++)
     {
-      rule_number_t *rp;
+      rule **rp;
       fprintf (stderr, "\t%s derives\n", symbols[i]->tag);
-      for (rp = derives[i]; *rp > 0; rp++)
+      for (rp = derives[i - ntokens]; *rp; ++rp)
        {
-         item_number_t *rhsp;
-         fprintf (stderr, "\t\t%d:", *rp);
-         for (rhsp = rules[*rp].rhs; *rhsp >= 0; ++rhsp)
-           fprintf (stderr, " %s", symbol_tag_get (symbols[*rhsp]));
-         fprintf (stderr, " (rule %d)\n",
-                  rule_number_of_item_number (*rhsp) - 1);
+         fprintf (stderr, "\t\t%3d ", (*rp)->user_number);
+         rule_rhs_print (*rp, stderr);
        }
     }
 
@@ -56,53 +62,60 @@ print_derives (void)
 
 
 void
-set_derives (void)
+derives_compute (void)
 {
-  symbol_number_t i;
-  rule_number_t r;
-  shorts *p;
-  rule_number_t *q;
-  shorts **dset;
-  shorts *delts;
-
-  dset = XCALLOC (shorts *, nvars) - ntokens;
-  delts = XCALLOC (shorts, nrules + 1);
-
-  p = delts;
-  for (r = nrules; r > 0; r--)
+  symbol_number i;
+  int r;
+  rule **q;
+
+  /* DSET[NTERM - NTOKENS] -- A linked list of the numbers of the rules
+     whose LHS is NTERM.  */
+  rule_list **dset = CALLOC (dset, nvars);
+
+  /* DELTS[RULE] -- There are NRULES rule number to attach to nterms.
+     Instead of performing NRULES allocations for each, have an array
+     indexed by rule numbers.  */
+  rule_list *delts = CALLOC (delts, nrules);
+
+  for (r = nrules - 1; r >= 0; --r)
     {
-      symbol_number_t lhs = rules[r].lhs->number;
-      p->next = dset[lhs];
-      p->value = r;
-      dset[lhs] = p;
-      p++;
+      symbol_number lhs = rules[r].lhs->number;
+      rule_list *p = &delts[r];
+      /* A new LHS is found.  */
+      p->next = dset[lhs - ntokens];
+      p->value = &rules[r];
+      dset[lhs - ntokens] = p;
     }
 
-  derives = XCALLOC (rule_number_t *, nvars) - ntokens;
-  q = XCALLOC (short, nvars + int_of_rule_number (nrules));
+  /* DSET contains what we need under the form of a linked list.  Make
+     it a single array.  */
+
+  CALLOC (derives, nvars);
+  CALLOC (q, nvars + nrules);
 
   for (i = ntokens; i < nsyms; i++)
     {
-      derives[i] = q;
-      p = dset[i];
+      rule_list *p = dset[i - ntokens];
+      derives[i - ntokens] = q;
       while (p)
        {
          *q++ = p->value;
          p = p->next;
        }
-      *q++ = -1;
+      *q++ = NULL;
     }
 
-  if (trace_flag)
+  if (trace_flag & trace_sets)
     print_derives ();
 
-  XFREE (dset + ntokens);
-  XFREE (delts);
+  free (dset);
+  free (delts);
 }
 
+
 void
-free_derives (void)
+derives_free (void)
 {
-  XFREE (derives[ntokens]);
-  XFREE (derives + ntokens);
+  XFREE (derives[0]);
+  XFREE (derives);
 }