* src/closure.c (firsts): Now, also a bitset.

[bison.git] / src / LR0.c

diff --git a/src/LR0.c b/src/LR0.c
index ff5fdb614123433ca3ccae7a386304b3fac067cd..6a911f240f47fe0bc569729854dd6c9e820aa4dc 100644 (file)
--- a/src/LR0.c
+++ b/src/LR0.c
@@ -23,6 +23,7 @@
    The entry point is generate_states.  */
 
 #include "system.h"
    The entry point is generate_states.  */
 
 #include "system.h"

+#include "symtab.h"

 #include "getargs.h"
 #include "reader.h"
 #include "gram.h"
 #include "getargs.h"
 #include "reader.h"
 #include "gram.h"


@@ -30,18 +31,22 @@
 #include "complain.h"
 #include "closure.h"
 #include "LR0.h"
 #include "complain.h"
 #include "closure.h"
 #include "LR0.h"

+#include "lalr.h"

 #include "reduce.h"
 
 int nstates;
 #include "reduce.h"
 
 int nstates;

-int final_state;
-state_t *first_state = NULL;
-shifts *first_shift = NULL;
-reductions *first_reduction = NULL;
+/* Initialize the final state to -1, otherwise, it might be set to 0
+   by default, and since we don't compute the reductions of the final
+   state, we end up not computing the reductions of the initial state,
+   which is of course needed.
+
+   FINAL_STATE is properly set by new_state when it recognizes the
+   accessing symbol: EOF.  */
+int final_state = -1;
+static state_t *first_state = NULL;

 
 static state_t *this_state = NULL;
 static state_t *last_state = NULL;
 
 static state_t *this_state = NULL;
 static state_t *last_state = NULL;

-static shifts *last_shift = NULL;
-static reductions *last_reduction = NULL;

 
 static int nshifts;
 static short *shift_symbol = NULL;
 
 static int nshifts;
 static short *shift_symbol = NULL;


@@ -71,8 +76,8 @@ allocate_itemsets (void)
   int count = 0;
   short *symbol_count = XCALLOC (short, nsyms + nuseless_nonterminals);
 
   int count = 0;
   short *symbol_count = XCALLOC (short, nsyms + nuseless_nonterminals);
 

-  for (i = 0; ritem[i]; ++i)
-    if (ritem[i] > 0)
+  for (i = 0; i < nritems; ++i)
+    if (ritem[i] >= 0)

       {
        count++;
        symbol_count[ritem[i]]++;
       {
        count++;
        symbol_count[ritem[i]]++;


@@ -108,6 +113,7 @@ allocate_storage (void)
   shiftset = XCALLOC (short, nsyms);
   redset = XCALLOC (short, nrules + 1);
   state_hash = XCALLOC (state_t *, STATE_HASH_SIZE);
   shiftset = XCALLOC (short, nsyms);
   redset = XCALLOC (short, nrules + 1);
   state_hash = XCALLOC (state_t *, STATE_HASH_SIZE);

+  shift_symbol = XCALLOC (short, nsyms);

 }
 
 
 }
 
 


@@ -149,13 +155,12 @@ new_itemsets (void)
   for (i = 0; i < nsyms; i++)
     kernel_size[i] = 0;
 
   for (i = 0; i < nsyms; i++)
     kernel_size[i] = 0;
 

-  shift_symbol = XCALLOC (short, nsyms);

   nshifts = 0;
 
   for (i = 0; i < nitemset; ++i)
     {
       int symbol = ritem[itemset[i]];
   nshifts = 0;
 
   for (i = 0; i < nitemset; ++i)
     {
       int symbol = ritem[itemset[i]];

-      if (symbol > 0)
+      if (symbol >= 0)

        {
          if (!kernel_size[symbol])
            {
        {
          if (!kernel_size[symbol])
            {


@@ -183,7 +188,7 @@ new_state (int symbol)
 
   if (trace_flag)
     fprintf (stderr, "Entering new_state, state = %d, symbol = %d (%s)\n",
 
   if (trace_flag)
     fprintf (stderr, "Entering new_state, state = %d, symbol = %d (%s)\n",

-            this_state->number, symbol, tags[symbol]);
+            this_state->number, symbol, symbols[symbol]->tag);

 
   if (nstates >= MAXSHORT)
     fatal (_("too many states (max %d)"), MAXSHORT);
 
   if (nstates >= MAXSHORT)
     fatal (_("too many states (max %d)"), MAXSHORT);


@@ -199,6 +204,10 @@ new_state (int symbol)
   last_state = p;
   nstates++;
 
   last_state = p;
   nstates++;
 

+  /* If this is the eoftoken, then this is the final state. */
+  if (symbol == 0)
+    final_state = p->number;
+

   return p;
 }
 
   return p;
 }
 


@@ -218,7 +227,7 @@ get_state (int symbol)
 
   if (trace_flag)
     fprintf (stderr, "Entering get_state, state = %d, symbol = %d (%s)\n",
 
   if (trace_flag)
     fprintf (stderr, "Entering get_state, state = %d, symbol = %d (%s)\n",

-            this_state->number, symbol, tags[symbol]);
+            this_state->number, symbol, symbols[symbol]->tag);

 
   /* Add up the target state's active item numbers to get a hash key.
      */
 
   /* Add up the target state's active item numbers to get a hash key.
      */


@@ -319,208 +328,8 @@ static void
 save_shifts (void)
 {
   shifts *p = shifts_new (nshifts);
 save_shifts (void)
 {
   shifts *p = shifts_new (nshifts);

-
-  p->number = this_state->number;
-

   shortcpy (p->shifts, shiftset, nshifts);
   shortcpy (p->shifts, shiftset, nshifts);

-
-  if (last_shift)
-    last_shift->next = p;
-  else
-    first_shift = p;
-  last_shift = p;
-}
-
-
-/*------------------------------------------------------------------.
-| Subroutine of augment_automaton.  Create the next-to-final state, |
-| to which a shift has already been made in the initial state.      |
-`------------------------------------------------------------------*/
-
-static void
-insert_start_shift (void)
-{
-  state_t *statep;
-  shifts *sp;
-
-  statep = STATE_ALLOC (0);
-  statep->number = nstates;
-  statep->accessing_symbol = start_symbol;
-
-  last_state->next = statep;
-  last_state = statep;
-
-  /* Make a shift from this state to (what will be) the final state.  */
-  sp = shifts_new (1);
-  sp->number = nstates++;
-  sp->shifts[0] = nstates;
-
-  last_shift->next = sp;
-  last_shift = sp;
-}
-
-
-/*------------------------------------------------------------------.
-| Make sure that the initial state has a shift that accepts the     |
-| grammar's start symbol and goes to the next-to-final state, which |
-| has a shift going to the final state, which has a shift to the    |
-| termination state.  Create such states and shifts if they don't   |
-| happen to exist already.                                          |
-`------------------------------------------------------------------*/
-
-static void
-augment_automaton (void)
-{
-  state_t *statep;
-  shifts *sp;
-  shifts *sp1 = NULL;
-
-  sp = first_shift;
-
-  if (!sp->nshifts)
-    {
-      /* There are no shifts for any state.  Make one shift, from the
-        initial state to the next-to-final state.  */
-
-      sp = shifts_new (1);
-      sp->shifts[0] = nstates;
-
-      /* Initialize the chain of shifts with sp.  */
-      first_shift = sp;
-      last_shift = sp;
-
-      /* Create the next-to-final state, with shift to
-         what will be the final state.  */
-      insert_start_shift ();
-    }
-  else if (sp->number == 0)
-    {
-      statep = first_state->next;
-
-      /* The states reached by shifts from FIRST_STATE are numbered
-        1..(SP->NSHIFTS).  Look for one reached by START_SYMBOL.  */
-      while (statep->accessing_symbol < start_symbol
-            && statep->number < sp->nshifts)
-       statep = statep->next;
-
-      if (statep->accessing_symbol == start_symbol)
-       {
-         /* We already have a next-to-final state.
-            Make sure it has a shift to what will be the final state.  */
-         while (sp && sp->number < statep->number)
-           {
-             sp1 = sp;
-             sp = sp->next;
-           }
-
-         if (sp && sp->number == statep->number)
-           {
-             int i;
-             shifts *sp2 = shifts_new (sp->nshifts + 1);
-             sp2->number = statep->number;
-             sp2->shifts[0] = nstates;
-             for (i = sp->nshifts; i > 0; i--)
-               sp2->shifts[i] = sp->shifts[i - 1];
-
-             /* Patch sp2 into the chain of shifts in place of sp,
-                following sp1.  */
-             sp2->next = sp->next;
-             sp1->next = sp2;
-             if (sp == last_shift)
-               last_shift = sp2;
-             XFREE (sp);
-           }
-         else
-           {
-             shifts *sp2 = shifts_new (1);
-             sp2->number = statep->number;
-             sp2->shifts[0] = nstates;
-
-             /* Patch sp2 into the chain of shifts between sp1 and sp.  */
-             sp2->next = sp;
-             sp1->next = sp2;
-             if (sp == 0)
-               last_shift = sp2;
-           }
-       }
-      else
-       {
-         int i, k;
-         shifts *sp2;
-
-         /* There is no next-to-final state as yet.  */
-         /* Add one more shift in first_shift,
-            going to the next-to-final state (yet to be made).  */
-         sp = first_shift;
-
-         sp2 = shifts_new (sp->nshifts + 1);
-
-         /* Stick this shift into the vector at the proper place.  */
-         statep = first_state->next;
-         for (k = 0, i = 0; i < sp->nshifts; k++, i++)
-           {
-             if (statep->accessing_symbol > start_symbol && i == k)
-               sp2->shifts[k++] = nstates;
-             sp2->shifts[k] = sp->shifts[i];
-             statep = statep->next;
-           }
-         if (i == k)
-           sp2->shifts[k++] = nstates;
-
-         /* Patch sp2 into the chain of shifts
-            in place of sp, at the beginning.  */
-         sp2->next = sp->next;
-         first_shift = sp2;
-         if (last_shift == sp)
-           last_shift = sp2;
-
-         XFREE (sp);
-
-         /* Create the next-to-final state, with shift to
-            what will be the final state.  */
-         insert_start_shift ();
-       }
-    }
-  else
-    {
-      /* The initial state didn't even have any shifts.
-        Give it one shift, to the next-to-final state.  */
-      sp = shifts_new (1);
-      sp->shifts[0] = nstates;
-
-      /* Patch sp into the chain of shifts at the beginning.  */
-      sp->next = first_shift;
-      first_shift = sp;
-
-      /* Create the next-to-final state, with shift to
-        what will be the final state.  */
-      insert_start_shift ();
-    }
-
-  /* Make the final state--the one that follows a shift from the
-     next-to-final state.
-     The symbol for that shift is 0 (end-of-file).  */
-  statep = STATE_ALLOC (0);
-  statep->number = nstates;
-  last_state->next = statep;
-  last_state = statep;
-
-  /* Make the shift from the final state to the termination state.  */
-  sp = shifts_new (1);
-  sp->number = nstates++;
-  sp->shifts[0] = nstates;
-  last_shift->next = sp;
-  last_shift = sp;
-
-  /* Note that the variable `final_state' refers to what we sometimes call
-     the termination state.  */
-  final_state = nstates;
-
-  /* Make the termination state.  */
-  statep = STATE_ALLOC (0);
-  statep->number = nstates++;
-  last_state->next = statep;
-  last_state = statep;
+  this_state->shifts = p;

 }
 
 
 }
 
 


@@ -533,12 +342,15 @@ augment_automaton (void)
 static void
 save_reductions (void)
 {
 static void
 save_reductions (void)
 {

-  int count;
+  int count = 0;

   int i;
 
   int i;
 

-  /* Find and count the active items that represent ends of rules. */
+  /* If this is the final state, we want it to have no reductions at
+     all, although it has one for `START_SYMBOL EOF .'.  */
+  if (this_state->number == final_state)
+    return;

 
 

-  count = 0;
+  /* Find and count the active items that represent ends of rules. */

   for (i = 0; i < nitemset; ++i)
     {
       int item = ritem[itemset[i]];
   for (i = 0; i < nitemset; ++i)
     {
       int item = ritem[itemset[i]];


@@ -547,25 +359,37 @@ save_reductions (void)
     }
 
   /* Make a reductions structure and copy the data into it.  */
     }
 
   /* Make a reductions structure and copy the data into it.  */

+  this_state->reductions = reductions_new (count);
+  shortcpy (this_state->reductions->rules, redset, count);
+}

 
 

-  if (count)
-    {
-      reductions *p = REDUCTIONS_ALLOC (count);
-
-      p->number = this_state->number;
-      p->nreds = count;
+\f
+/*---------------.
+| Build STATES.  |
+`---------------*/

 
 

-      shortcpy (p->rules, redset, count);
+static void
+set_states (void)
+{
+  state_t *sp;
+  states = XCALLOC (state_t *, nstates);

 
 

-      if (last_reduction)
-       last_reduction->next = p;
-      else
-       first_reduction = p;
-      last_reduction = p;
+  for (sp = first_state; sp; sp = sp->next)
+    {
+      /* Pessimization, but simplification of the code: make sure all
+        the states have a shifts, errs, and reductions, even if
+        reduced to 0.  */
+      if (!sp->shifts)
+       sp->shifts = shifts_new (0);
+      if (!sp->errs)
+       sp->errs = errs_new (0);
+      if (!sp->reductions)
+       sp->reductions = reductions_new (0);
+
+      states[sp->number] = sp;

     }
 }
 
     }
 }
 

-\f

 /*-------------------------------------------------------------------.
 | Compute the nondeterministic finite state machine (see state.h for |
 | details) from the grammar.                                         |
 /*-------------------------------------------------------------------.
 | Compute the nondeterministic finite state machine (see state.h for |
 | details) from the grammar.                                         |


@@ -575,14 +399,15 @@ void
 generate_states (void)
 {
   allocate_storage ();
 generate_states (void)
 {
   allocate_storage ();

-  new_closure (nitems);
+  new_closure (nritems);

   new_states ();
 
   while (this_state)
     {
       if (trace_flag)
        fprintf (stderr, "Processing state %d (reached by %s)\n",
   new_states ();
 
   while (this_state)
     {
       if (trace_flag)
        fprintf (stderr, "Processing state %d (reached by %s)\n",

-                this_state->number, tags[this_state->accessing_symbol]);
+                this_state->number,
+                symbols[this_state->accessing_symbol]->tag);

       /* Set up ruleset and itemset for the transitions out of this
          state.  ruleset gets a 1 bit for each rule that could reduce
          now.  itemset gets a vector of all the items that could be
       /* Set up ruleset and itemset for the transitions out of this
          state.  ruleset gets a 1 bit for each rule that could reduce
          now.  itemset gets a vector of all the items that could be


@@ -607,6 +432,6 @@ generate_states (void)
   free_closure ();
   free_storage ();
 
   free_closure ();
   free_storage ();
 

-  /* set up initial and final states as parser wants them */
-  augment_automaton ();
+  /* Set up STATES. */
+  set_states ();

 }
 }