X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/5967f0cf594cf19cd596b171392cc51bbd0ee596..728c4be2:/src/state.c?ds=sidebyside

diff --git a/src/state.c b/src/state.c
index bae3575e..3ba592bf 100644
--- a/src/state.c
+++ b/src/state.c
@@ -1,6 +1,6 @@
 /* Type definitions for nondeterministic finite state machine for Bison.
 
-   Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006 Free Software
+   Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007 Free Software
    Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
@@ -145,7 +145,6 @@ state_new (symbol_number accessing_symbol,
   res->errs = NULL;
   res->consistent = 0;
   res->solved_conflicts = NULL;
-  res->reachable = false;
 
   res->nitems = nitems;
   memcpy (res->items, core, items_size);
@@ -354,41 +353,49 @@ state_hash_lookup (size_t nitems, item_number *core)
 }
 
 
-/*------------------------------------------------------.
-| Mark S and all states reachable from S as reachable.  |
-`------------------------------------------------------*/
+/*--------------------------------------------------------.
+| Record S and all states reachable from S in REACHABLE.  |
+`--------------------------------------------------------*/
 
 static void
-state_mark_reachable_states (state *s)
+state_record_reachable_states (state *s, bitset reachable)
 {
-  if (s->reachable)
+  if (bitset_test (reachable, s->number))
     return;
-  s->reachable = true;
-  for (int i = 0; i < s->transitions->num; ++i)
-    if (!TRANSITION_IS_DISABLED (s->transitions, i))
-      state_mark_reachable_states (s->transitions->states[i]);
+  bitset_set (reachable, s->number);
+  {
+    int i;
+    for (i = 0; i < s->transitions->num; ++i)
+      if (!TRANSITION_IS_DISABLED (s->transitions, i))
+        state_record_reachable_states (s->transitions->states[i], reachable);
+  }
 }
 
 void
 state_remove_unreachable_states (state_number old_to_new[])
 {
   state_number nstates_reachable = 0;
-  state_mark_reachable_states (states[0]);
-  for (state_number i = 0; i < nstates; ++i)
-    {
-      if (states[i]->reachable)
-        {
-          states[nstates_reachable] = states[i];
-          states[nstates_reachable]->number = nstates_reachable;
-          old_to_new[i] = nstates_reachable++;
-        }
-      else
-        {
-          state_free (states[i]);
-          old_to_new[i] = nstates;
-        }
-    }
+  bitset reachable = bitset_create (nstates, BITSET_FIXED);
+  state_record_reachable_states (states[0], reachable);
+  {
+    state_number i;
+    for (i = 0; i < nstates; ++i)
+      {
+        if (bitset_test (reachable, states[i]->number))
+          {
+            states[nstates_reachable] = states[i];
+            states[nstates_reachable]->number = nstates_reachable;
+            old_to_new[i] = nstates_reachable++;
+          }
+        else
+          {
+            state_free (states[i]);
+            old_to_new[i] = nstates;
+          }
+      }
+  }
   nstates = nstates_reachable;
+  bitset_free (reachable);
 }
 
 /* All the decorated states, indexed by the state number.  */