Instead of attaching lookaheads and duplicating the rules being

[bison.git] / src / lalr.c

diff --git a/src/lalr.c b/src/lalr.c
index a889677b07de89f12304f68cce2d19325a97731d..2c0c942aeb216ab26c958efa11b616a5c0753de3 100644 (file)
--- a/src/lalr.c
+++ b/src/lalr.c
@@ -32,7 +32,6 @@
 #include "symtab.h"
 #include "gram.h"
 #include "reader.h"
 #include "symtab.h"
 #include "gram.h"
 #include "reader.h"

-#include "types.h"

 #include "LR0.h"
 #include "complain.h"
 #include "lalr.h"
 #include "LR0.h"
 #include "complain.h"
 #include "lalr.h"


@@ -40,66 +39,56 @@
 #include "derives.h"
 #include "getargs.h"
 
 #include "derives.h"
 #include "getargs.h"
 

-rule_t **LArule = NULL;
-bitsetv LA = NULL;
-size_t nLA;
-
-static int ngotos;
-short *goto_map = NULL;
+goto_number_t *goto_map = NULL;
+static goto_number_t ngotos = 0;

 state_number_t *from_state = NULL;
 state_number_t *to_state = NULL;
 
 state_number_t *from_state = NULL;
 state_number_t *to_state = NULL;
 

-/* And for the famous F variable, which name is so descriptive that a
-   comment is hardly needed.  <grin>.  */
-static bitsetv F = NULL;
+/* Linked list of goto numbers.  */
+typedef struct goto_list_s
+{
+  struct goto_list_s *next;
+  goto_number_t value;
+} goto_list_t;

 
 

-static short **includes;
-static shorts **lookback;

 
 

+/* LA is a LR by NTOKENS matrix of bits.  LA[l, i] is 1 if the rule
+   LArule[l] is applicable in the appropriate state when the next
+   token is symbol i.  If LA[l, i] and LA[l, j] are both 1 for i != j,
+   it is a conflict.  */

 
 

+static bitsetv LA = NULL;
+size_t nLA;

 
 
 
 

-static void
-initialize_LA (void)
-{
-  state_number_t i;
-  int j;
-  rule_t **np;
+/* And for the famous F variable, which name is so descriptive that a
+   comment is hardly needed.  <grin>.  */
+static bitsetv F = NULL;

 
 

-  /* Avoid having to special case 0.  */
-  if (!nLA)
-    nLA = 1;
+static goto_number_t **includes;
+static goto_list_t **lookback;

 
 

-  LA = bitsetv_create (nLA, ntokens, BITSET_FIXED);
-  LArule = XCALLOC (rule_t *, nLA);
-  lookback = XCALLOC (shorts *, nLA);

 
 

-  np = LArule;
-  for (i = 0; i < nstates; i++)
-    if (!states[i]->consistent)
-      for (j = 0; j < states[i]->reductions->num; j++)
-       *np++ = &rules[states[i]->reductions->rules[j]];
-}

 
 
 static void
 set_goto_map (void)
 {
   state_number_t state;
 
 
 static void
 set_goto_map (void)
 {
   state_number_t state;

-  short *temp_map;
+  goto_number_t *temp_map;

 
 

-  goto_map = XCALLOC (short, nvars + 1) - ntokens;
-  temp_map = XCALLOC (short, nvars + 1) - ntokens;
+  goto_map = XCALLOC (goto_number_t, nvars + 1) - ntokens;
+  temp_map = XCALLOC (goto_number_t, nvars + 1) - ntokens;

 
   ngotos = 0;
   for (state = 0; state < nstates; ++state)
     {
 
   ngotos = 0;
   for (state = 0; state < nstates; ++state)
     {

-      transitions_t *sp = states[state]->shifts;
+      transitions_t *sp = states[state]->transitions;

       int i;
       for (i = sp->num - 1; i >= 0 && TRANSITION_IS_GOTO (sp, i); --i)
        {
       int i;
       for (i = sp->num - 1; i >= 0 && TRANSITION_IS_GOTO (sp, i); --i)
        {

-         if (ngotos == SHRT_MAX)
-           fatal (_("too many gotos (max %d)"), SHRT_MAX);
+         if (ngotos == GOTO_NUMBER_MAX)
+           fatal (_("too many gotos (max %d)"), GOTO_NUMBER_MAX);

 
          ngotos++;
          goto_map[TRANSITION_SYMBOL (sp, i)]++;
 
          ngotos++;
          goto_map[TRANSITION_SYMBOL (sp, i)]++;


@@ -127,13 +116,13 @@ set_goto_map (void)
 
   for (state = 0; state < nstates; ++state)
     {
 
   for (state = 0; state < nstates; ++state)
     {

-      transitions_t *sp = states[state]->shifts;
+      transitions_t *sp = states[state]->transitions;

       int i;
       for (i = sp->num - 1; i >= 0 && TRANSITION_IS_GOTO (sp, i); --i)
        {
          int k = temp_map[TRANSITION_SYMBOL (sp, i)]++;
          from_state[k] = state;
       int i;
       for (i = sp->num - 1; i >= 0 && TRANSITION_IS_GOTO (sp, i); --i)
        {
          int k = temp_map[TRANSITION_SYMBOL (sp, i)]++;
          from_state[k] = state;

-         to_state[k] = sp->states[i];
+         to_state[k] = sp->states[i]->number;

        }
     }
 
        }
     }
 


@@ -178,8 +167,8 @@ map_goto (state_number_t state, symbol_number_t symbol)
 static void
 initialize_F (void)
 {
 static void
 initialize_F (void)
 {

-  short **reads = XCALLOC (short *, ngotos);
-  short *edge = XCALLOC (short, ngotos + 1);
+  goto_number_t **reads = XCALLOC (goto_number_t *, ngotos);
+  goto_number_t *edge = XCALLOC (goto_number_t, ngotos + 1);

   int nedges = 0;
 
   int i;
   int nedges = 0;
 
   int i;


@@ -189,10 +178,10 @@ initialize_F (void)
   for (i = 0; i < ngotos; i++)
     {
       state_number_t stateno = to_state[i];
   for (i = 0; i < ngotos; i++)
     {
       state_number_t stateno = to_state[i];

-      transitions_t *sp = states[stateno]->shifts;
+      transitions_t *sp = states[stateno]->transitions;

 
       int j;
 
       int j;

-      for (j = 0; j < sp->num && TRANSITION_IS_SHIFT (sp, j); j++)
+      FOR_EACH_SHIFT (sp, j)

        bitset_set (F[i], TRANSITION_SYMBOL (sp, j));
 
       for (; j < sp->num; j++)
        bitset_set (F[i], TRANSITION_SYMBOL (sp, j));
 
       for (; j < sp->num; j++)


@@ -204,7 +193,7 @@ initialize_F (void)
 
       if (nedges)
        {
 
       if (nedges)
        {

-         reads[i] = XCALLOC (short, nedges + 1);
+         reads[i] = XCALLOC (goto_number_t, nedges + 1);

          memcpy (reads[i], edge, nedges * sizeof (edge[0]));
          reads[i][nedges] = -1;
          nedges = 0;
          memcpy (reads[i], edge, nedges * sizeof (edge[0]));
          reads[i][nedges] = -1;
          nedges = 0;


@@ -222,21 +211,13 @@ initialize_F (void)
 
 
 static void
 
 
 static void

-add_lookback_edge (state_t *state, rule_number_t ruleno, int gotono)
+add_lookback_edge (state_t *state, rule_t *rule, int gotono)

 {
 {

-  int i;
-  shorts *sp;
-
-  for (i = 0; i < state->nlookaheads; ++i)
-    if (state->lookaheads_rule[i]->number == ruleno)
-      break;
-
-  assert (state->lookaheads_rule[i]->number == ruleno);
-
-  sp = XCALLOC (shorts, 1);
-  sp->next = lookback[(state->lookaheads - LA) + i];
+  int r = state_reduction_find (state, rule);
+  goto_list_t *sp = XCALLOC (goto_list_t, 1);
+  sp->next = lookback[(state->reductions->lookaheads - LA) + r];

   sp->value = gotono;
   sp->value = gotono;

-  lookback[(state->lookaheads - LA) + i] = sp;
+  lookback[(state->reductions->lookaheads - LA) + r] = sp;

 }
 
 
 }
 
 


@@ -244,19 +225,19 @@ add_lookback_edge (state_t *state, rule_number_t ruleno, int gotono)
 static void
 build_relations (void)
 {
 static void
 build_relations (void)
 {

-  short *edge = XCALLOC (short, ngotos + 1);
+  goto_number_t *edge = XCALLOC (goto_number_t, ngotos + 1);

   state_number_t *states1 = XCALLOC (state_number_t, ritem_longest_rhs () + 1);
   int i;
 
   state_number_t *states1 = XCALLOC (state_number_t, ritem_longest_rhs () + 1);
   int i;
 

-  includes = XCALLOC (short *, ngotos);
+  includes = XCALLOC (goto_number_t *, ngotos);

 
   for (i = 0; i < ngotos; i++)
     {
       int nedges = 0;
       symbol_number_t symbol1 = states[to_state[i]]->accessing_symbol;
 
   for (i = 0; i < ngotos; i++)
     {
       int nedges = 0;
       symbol_number_t symbol1 = states[to_state[i]]->accessing_symbol;

-      rule_number_t *rulep;
+      rule_t **rulep;

 
 

-      for (rulep = derives[symbol1]; *rulep > 0; rulep++)
+      for (rulep = derives[symbol1]; *rulep; rulep++)

        {
          int done;
          int length = 1;
        {
          int done;
          int length = 1;


@@ -264,10 +245,10 @@ build_relations (void)
          state_t *state = states[from_state[i]];
          states1[0] = state->number;
 
          state_t *state = states[from_state[i]];
          states1[0] = state->number;
 

-         for (rp = rules[*rulep].rhs; *rp >= 0; rp++)
+         for (rp = (*rulep)->rhs; *rp >= 0; rp++)

            {
            {

-             state = transitions_to (state->shifts,
-                                item_number_as_symbol_number (*rp));
+             state = transitions_to (state->transitions,
+                                     item_number_as_symbol_number (*rp));

              states1[length++] = state->number;
            }
 
              states1[length++] = state->number;
            }
 


@@ -295,7 +276,7 @@ build_relations (void)
       if (nedges)
        {
          int j;
       if (nedges)
        {
          int j;

-         includes[i] = XCALLOC (short, nedges + 1);
+         includes[i] = XCALLOC (goto_number_t, nedges + 1);

          for (j = 0; j < nedges; j++)
            includes[i][j] = edge[j];
          includes[i][nedges] = -1;
          for (j = 0; j < nedges; j++)
            includes[i][j] = edge[j];
          includes[i][nedges] = -1;


@@ -328,7 +309,7 @@ static void
 compute_lookaheads (void)
 {
   size_t i;
 compute_lookaheads (void)
 {
   size_t i;

-  shorts *sp;
+  goto_list_t *sp;

 
   for (i = 0; i < nLA; i++)
     for (sp = lookback[i]; sp; sp = sp->next)
 
   for (i = 0; i < nLA; i++)
     for (sp = lookback[i]; sp; sp = sp->next)


@@ -336,74 +317,79 @@ compute_lookaheads (void)
 
   /* Free LOOKBACK. */
   for (i = 0; i < nLA; i++)
 
   /* Free LOOKBACK. */
   for (i = 0; i < nLA; i++)

-    LIST_FREE (shorts, lookback[i]);
+    LIST_FREE (goto_list_t, lookback[i]);

 
   XFREE (lookback);
   bitsetv_free (F);
 }
 
 
 
   XFREE (lookback);
   bitsetv_free (F);
 }
 
 

-/*-------------------------------------------------------------.
-| Count the number of lookaheads required for each state       |
-| (NLOOKAHEADS member).  Compute the total number of LA, NLA.  |
-`-------------------------------------------------------------*/
+/*---------------------------------------------------------------.
+| Count the number of lookaheads required for STATE (NLOOKAHEADS |
+| member).                                                       |
+`---------------------------------------------------------------*/

 
 

-static void
-states_lookaheads_count (void)
+static int
+state_lookaheads_count (state_t *state)

 {
 {

-  state_number_t i;
-  nLA = 0;
-
-  /* Count   */
-  for (i = 0; i < nstates; i++)
-    {
-      int k;
-      int nlookaheads = 0;
-      reductions_t *rp = states[i]->reductions;
-      transitions_t *sp = states[i]->shifts;
-
-      /* We need a lookahead either to distinguish different
-        reductions (i.e., there are two or more), or to distinguish a
-        reduction from a shift.  Otherwise, it is straightforward,
-        and the state is `consistent'.  */
-      if (rp->num > 1
-         || (rp->num == 1 && sp->num && TRANSITION_IS_SHIFT (sp, 0)))
-       nlookaheads += rp->num;
-      else
-       states[i]->consistent = 1;
-
-      for (k = 0; k < sp->num; k++)
-       if (TRANSITION_IS_ERROR (sp, k))
-         {
-           states[i]->consistent = 0;
-           break;
-         }
+  int k;
+  int nlookaheads = 0;
+  reductions_t *rp = state->reductions;
+  transitions_t *sp = state->transitions;
+
+  /* We need a lookahead either to distinguish different
+     reductions (i.e., there are two or more), or to distinguish a
+     reduction from a shift.  Otherwise, it is straightforward,
+     and the state is `consistent'.  */
+  if (rp->num > 1
+      || (rp->num == 1 && sp->num &&
+         !TRANSITION_IS_DISABLED (sp, 0) && TRANSITION_IS_SHIFT (sp, 0)))
+    nlookaheads += rp->num;
+  else
+    state->consistent = 1;
+
+  for (k = 0; k < sp->num; k++)
+    if (!TRANSITION_IS_DISABLED (sp, k) && TRANSITION_IS_ERROR (sp, k))
+      {
+       state->consistent = 0;
+       break;
+      }

 
 

-      states[i]->nlookaheads = nlookaheads;
-      nLA += nlookaheads;
-    }
+  return nlookaheads;

 }
 
 
 }
 
 

-/*--------------------------------------.
-| Initializing the lookaheads members.  |
-`--------------------------------------*/
+/*----------------------------------------------.
+| Compute LA, NLA, and the lookaheads members.  |
+`----------------------------------------------*/

 
 static void
 
 static void

-states_lookaheads_initialize (void)
+initialize_LA (void)

 {
   state_number_t i;
 {
   state_number_t i;

-  bitsetv pLA = LA;
-  rule_t **pLArule = LArule;
+  bitsetv pLA;

 
 

-  /* Initialize the members LOOKAHEADS and LOOKAHEADS_RULE for each
-     state.  */
+  /* Compute the total number of reductions requiring a lookahead.  */
+  nLA = 0;
+  for (i = 0; i < nstates; i++)
+    nLA += state_lookaheads_count (states[i]);
+  /* Avoid having to special case 0.  */
+  if (!nLA)
+    nLA = 1;
+
+  pLA = LA = bitsetv_create (nLA, ntokens, BITSET_FIXED);
+  lookback = XCALLOC (goto_list_t *, nLA);
+
+  /* Initialize the members LOOKAHEADS for each state which reductions
+     require lookaheads.  */

   for (i = 0; i < nstates; i++)
     {
   for (i = 0; i < nstates; i++)
     {

-      states[i]->lookaheads = pLA;
-      states[i]->lookaheads_rule = pLArule;
-      pLA += states[i]->nlookaheads;
-      pLArule += states[i]->nlookaheads;
+      int count = state_lookaheads_count (states[i]);
+      if (count)
+       {
+         states[i]->reductions->lookaheads = pLA;
+         pLA += count;
+       }

     }
 }
 
     }
 }
 


@@ -420,16 +406,26 @@ lookaheads_print (FILE *out)
   fprintf (out, "Lookaheads: BEGIN\n");
   for (i = 0; i < nstates; ++i)
     {
   fprintf (out, "Lookaheads: BEGIN\n");
   for (i = 0; i < nstates; ++i)
     {

+      reductions_t *reds = states[i]->reductions;
+      bitset_iterator iter;
+      int nlookaheads = 0;
+
+      if (reds->lookaheads)
+       for (k = 0; k < reds->num; ++k)
+         if (reds->lookaheads[k])
+           ++nlookaheads;
+

       fprintf (out, "State %d: %d lookaheads\n",
       fprintf (out, "State %d: %d lookaheads\n",

-              i, states[i]->nlookaheads);
+              i, nlookaheads);

 
 

-      for (j = 0; j < states[i]->nlookaheads; ++j)
-       BITSET_EXECUTE (states[i]->lookaheads[j], 0, k,
-       {
-         fprintf (out, "   on %d (%s) -> rule %d\n",
-                  k, symbol_tag_get (symbols[k]),
-                  states[i]->lookaheads_rule[j]->number - 1);
-       });
+      if (reds->lookaheads)
+       for (j = 0; j < reds->num; ++j)
+         BITSET_FOR_EACH (iter, reds->lookaheads[j], k, 0)
+         {
+           fprintf (out, "   on %d (%s) -> rule %d\n",
+                    k, symbols[k]->tag,
+                    reds->rules[j]->number);
+         };

     }
   fprintf (out, "Lookaheads: END\n");
 }
     }
   fprintf (out, "Lookaheads: END\n");
 }


@@ -437,15 +433,23 @@ lookaheads_print (FILE *out)
 void
 lalr (void)
 {
 void
 lalr (void)
 {

-  states_lookaheads_count ();

   initialize_LA ();
   initialize_LA ();

-  states_lookaheads_initialize ();

   set_goto_map ();
   initialize_F ();
   build_relations ();
   compute_FOLLOWS ();
   compute_lookaheads ();
 
   set_goto_map ();
   initialize_F ();
   build_relations ();
   compute_FOLLOWS ();
   compute_lookaheads ();
 

-  if (trace_flag)
+  if (trace_flag & trace_sets)

     lookaheads_print (stderr);
 }
     lookaheads_print (stderr);
 }

+
+
+void
+lalr_free (void)
+{
+  state_number_t s;
+  for (s = 0; s < nstates; ++s)
+    states[s]->reductions->lookaheads = NULL;
+  bitsetv_free (LA);
+}