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[bison.git] / src / lalr.c

diff --git a/src/lalr.c b/src/lalr.c
index 0b26925580c370a826d098425ee17b26fff61a76..c16c6f52dafaea945a222c3f6103f32c6c312cf2 100644 (file)
--- a/src/lalr.c
+++ b/src/lalr.c
@@ -24,8 +24,10 @@
    tokens they accept.  */
 
 #include "system.h"
    tokens they accept.  */
 
 #include "system.h"

+#include "reader.h"

 #include "types.h"
 #include "LR0.h"
 #include "types.h"
 #include "LR0.h"

+#include "symtab.h"

 #include "gram.h"
 #include "complain.h"
 #include "lalr.h"
 #include "gram.h"
 #include "complain.h"
 #include "lalr.h"


@@ -33,14 +35,13 @@
 #include "derives.h"
 #include "getargs.h"
 
 #include "derives.h"
 #include "getargs.h"
 

-/* All the decorated states, indexed by the state number.  Warning:
-   there is a state_TABLE in LR0.c, but it is different and static.
-   */
-state_t **state_table = NULL;
+/* All the decorated states, indexed by the state number.  */
+state_t **states = NULL;

 
 int tokensetsize;
 short *LAruleno;
 unsigned *LA;
 
 int tokensetsize;
 short *LAruleno;
 unsigned *LA;

+size_t nLA;

 
 static int ngotos;
 short *goto_map;
 
 static int ngotos;
 short *goto_map;


@@ -103,7 +104,7 @@ traverse (int i)
          break;
 
        for (k = 0; k < size; ++k)
          break;
 
        for (k = 0; k < size; ++k)

-         F (i)[k] = F (j)[k];
+         F (j)[k] = F (i)[k];

       }
 }
 
       }
 }
 


@@ -132,89 +133,14 @@ digraph (short **relation)
 }
 
 
 }
 
 

-/*--------------------.
-| Build STATE_TABLE.  |
-`--------------------*/
-
-static void
-set_state_table (void)
-{
-  /* NSTATES + 1 because lookahead for the pseudo state number NSTATES
-     might be used (see conflicts.c).  It is too opaque for me to
-     provide a probably less hacky implementation. --akim */
-  state_table = XCALLOC (state_t *, nstates + 1);
-
-  {
-    state_t *sp;
-    for (sp = first_state; sp; sp = sp->next)
-      state_table[sp->number] = sp;
-  }
-
-  {
-    shifts *sp;
-    for (sp = first_shift; sp; sp = sp->next)
-      state_table[sp->number]->shifts = sp;
-  }
-
-  {
-    reductions *rp;
-    for (rp = first_reduction; rp; rp = rp->next)
-      state_table[rp->number]->reductions = rp;
-  }
-
-  /* Pessimization, but simplification of the code: make sure all the
-     states have a shifts, even if reduced to 0 shifts.  */
-  {
-    int i;
-    for (i = 0; i < nstates; i++)
-      if (!state_table[i]->shifts)
-       state_table[i]->shifts = shifts_new (0);
-  }
-
-  /* Initializing the lookaheads members.  Please note that it must be
-     performed after having set some of the other members which are
-     used below.  Change with extreme caution.  */
-  {
-    int i;
-    int count = 0;
-    for (i = 0; i < nstates; i++)
-      {
-       int k;
-       reductions *rp = state_table[i]->reductions;
-       shifts *sp = state_table[i]->shifts;
-
-       state_table[i]->lookaheads = count;
-
-       if (rp
-           && (rp->nreds > 1 || (sp->nshifts && SHIFT_IS_SHIFT (sp, 0))))
-         count += rp->nreds;
-       else
-         state_table[i]->consistent = 1;
-
-       for (k = 0; k < sp->nshifts; k++)
-         if (SHIFT_IS_ERROR (sp, k))
-           {
-             state_table[i]->consistent = 0;
-             break;
-           }
-      }
-
-    /* Seems to be needed by conflicts.c. */
-    state_table[nstates] = STATE_ALLOC (0);
-    state_table[nstates]->lookaheads = count;
-  }
-}
-
-

 static void
 initialize_LA (void)
 {
   int i;
   int j;
   short *np;
 static void
 initialize_LA (void)
 {
   int i;
   int j;
   short *np;

-  reductions *rp;

 
 

-  size_t nLA = state_table[nstates]->lookaheads;
+  /* Avoid having to special case 0.  */

   if (!nLA)
     nLA = 1;
 
   if (!nLA)
     nLA = 1;
 


@@ -224,67 +150,61 @@ initialize_LA (void)
 
   np = LAruleno;
   for (i = 0; i < nstates; i++)
 
   np = LAruleno;
   for (i = 0; i < nstates; i++)

-    if (!state_table[i]->consistent)
-      if ((rp = state_table[i]->reductions))
-       for (j = 0; j < rp->nreds; j++)
-         *np++ = rp->rules[j];
+    if (!states[i]->consistent)
+      for (j = 0; j < states[i]->reductions->nreds; j++)
+       *np++ = states[i]->reductions->rules[j];

 }
 
 
 static void
 set_goto_map (void)
 {
 }
 
 
 static void
 set_goto_map (void)
 {

-  shifts *sp;
-  int i;
-  int symbol;
-  int k;
+  int state, i;

   short *temp_map;
   short *temp_map;

-  int state2;
-  int state1;

 
   goto_map = XCALLOC (short, nvars + 1) - ntokens;
   temp_map = XCALLOC (short, nvars + 1) - ntokens;
 
   ngotos = 0;
 
   goto_map = XCALLOC (short, nvars + 1) - ntokens;
   temp_map = XCALLOC (short, nvars + 1) - ntokens;
 
   ngotos = 0;

-  for (sp = first_shift; sp; sp = sp->next)
-    for (i = sp->nshifts - 1; i >= 0 && SHIFT_IS_GOTO (sp, i); --i)
-      {
-       symbol = state_table[sp->shifts[i]]->accessing_symbol;
+  for (state = 0; state < nstates; ++state)
+    {
+      shifts *sp = states[state]->shifts;
+      for (i = sp->nshifts - 1; i >= 0 && SHIFT_IS_GOTO (sp, i); --i)
+       {
+         if (ngotos == MAXSHORT)
+           fatal (_("too many gotos (max %d)"), MAXSHORT);

 
 

-       if (ngotos == MAXSHORT)
-         fatal (_("too many gotos (max %d)"), MAXSHORT);
+         ngotos++;
+         goto_map[SHIFT_SYMBOL (sp, i)]++;
+       }
+    }

 
 

-       ngotos++;
-       goto_map[symbol]++;
+  {
+    int k = 0;
+    for (i = ntokens; i < nsyms; i++)
+      {
+       temp_map[i] = k;
+       k += goto_map[i];

       }
 
       }
 

-  k = 0;
-  for (i = ntokens; i < nsyms; i++)
-    {
-      temp_map[i] = k;
-      k += goto_map[i];
-    }
+    for (i = ntokens; i < nsyms; i++)
+      goto_map[i] = temp_map[i];

 
 

-  for (i = ntokens; i < nsyms; i++)
-    goto_map[i] = temp_map[i];
-
-  goto_map[nsyms] = ngotos;
-  temp_map[nsyms] = ngotos;
+    goto_map[nsyms] = ngotos;
+    temp_map[nsyms] = ngotos;
+  }

 
   from_state = XCALLOC (short, ngotos);
   to_state = XCALLOC (short, ngotos);
 
 
   from_state = XCALLOC (short, ngotos);
   to_state = XCALLOC (short, ngotos);
 

-  for (sp = first_shift; sp; sp = sp->next)
+  for (state = 0; state < nstates; ++state)

     {
     {

-      state1 = sp->number;
+      shifts *sp = states[state]->shifts;

       for (i = sp->nshifts - 1; i >= 0 && SHIFT_IS_GOTO (sp, i); --i)
        {
       for (i = sp->nshifts - 1; i >= 0 && SHIFT_IS_GOTO (sp, i); --i)
        {

-         state2 = sp->shifts[i];
-         symbol = state_table[state2]->accessing_symbol;
-
-         k = temp_map[symbol]++;
-         from_state[k] = state1;
-         to_state[k] = state2;
+         int k = temp_map[SHIFT_SYMBOL (sp, i)]++;
+         from_state[k] = state;
+         to_state[k] = sp->shifts[i];

        }
     }
 
        }
     }
 


@@ -340,18 +260,15 @@ initialize_F (void)
   for (i = 0; i < ngotos; i++)
     {
       int stateno = to_state[i];
   for (i = 0; i < ngotos; i++)
     {
       int stateno = to_state[i];

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

 
       int j;
       for (j = 0; j < sp->nshifts && SHIFT_IS_SHIFT (sp, j); j++)
 
       int j;
       for (j = 0; j < sp->nshifts && SHIFT_IS_SHIFT (sp, j); j++)

-       {
-         int symbol = state_table[sp->shifts[j]]->accessing_symbol;
-         SETBIT (F (i), symbol);
-       }
+       SETBIT (F (i), SHIFT_SYMBOL (sp, j));

 
       for (; j < sp->nshifts; j++)
        {
 
       for (; j < sp->nshifts; j++)
        {

-         int symbol = state_table[sp->shifts[j]]->accessing_symbol;
+         int symbol = SHIFT_SYMBOL (sp, j);

          if (nullable[symbol])
            edge[nedges++] = map_goto (stateno, symbol);
        }
          if (nullable[symbol])
            edge[nedges++] = map_goto (stateno, symbol);
        }


@@ -376,30 +293,21 @@ initialize_F (void)
 
 
 static void
 
 
 static void

-add_lookback_edge (int stateno, int ruleno, int gotono)
+add_lookback_edge (state_t *state, int ruleno, int gotono)

 {
   int i;
 {
   int i;

-  int k;
-  int found;

   shorts *sp;
 
   shorts *sp;
 

-  i = state_table[stateno]->lookaheads;
-  k = state_table[stateno + 1]->lookaheads;
-  found = 0;
-  while (!found && i < k)
-    {
-      if (LAruleno[i] == ruleno)
-       found = 1;
-      else
-       i++;
-    }
+  for (i = 0; i < state->nlookaheads; ++i)
+    if (LAruleno[state->lookaheadsp + i] == ruleno)
+      break;

 
 

-  assert (found);
+  assert (LAruleno[state->lookaheadsp + i] == ruleno);

 
   sp = XCALLOC (shorts, 1);
 
   sp = XCALLOC (shorts, 1);

-  sp->next = lookback[i];
+  sp->next = lookback[state->lookaheadsp + i];

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

-  lookback[i] = sp;
+  lookback[state->lookaheadsp + i] = sp;

 }
 
 
 }
 
 


@@ -493,7 +401,7 @@ static void
 build_relations (void)
 {
   short *edge = XCALLOC (short, ngotos + 1);
 build_relations (void)
 {
   short *edge = XCALLOC (short, ngotos + 1);

-  short *states = XCALLOC (short, ritem_longest_rhs () + 1);
+  short *states1 = XCALLOC (short, ritem_longest_rhs () + 1);

   int i;
 
   includes = XCALLOC (short *, ngotos);
   int i;
 
   includes = XCALLOC (short *, ngotos);


@@ -501,34 +409,33 @@ build_relations (void)
   for (i = 0; i < ngotos; i++)
     {
       int nedges = 0;
   for (i = 0; i < ngotos; i++)
     {
       int nedges = 0;

-      int state1 = from_state[i];
-      int symbol1 = state_table[to_state[i]]->accessing_symbol;
+      int symbol1 = states[to_state[i]]->accessing_symbol;

       short *rulep;
 
       for (rulep = derives[symbol1]; *rulep > 0; rulep++)
        {
          int done;
          int length = 1;
       short *rulep;
 
       for (rulep = derives[symbol1]; *rulep > 0; rulep++)
        {
          int done;
          int length = 1;

-         int stateno = state1;

          short *rp;
          short *rp;

-         states[0] = state1;
+         state_t *state = states[from_state[i]];
+         states1[0] = state->number;

 
 

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

            {
            {

-             shifts *sp = state_table[stateno]->shifts;
+             shifts *sp = state->shifts;

              int j;
              for (j = 0; j < sp->nshifts; j++)
                {
              int j;
              for (j = 0; j < sp->nshifts; j++)
                {

-                 stateno = sp->shifts[j];
-                 if (state_table[stateno]->accessing_symbol == *rp)
+                 state = states[sp->shifts[j]];
+                 if (state->accessing_symbol == *rp)

                    break;
                }
 
                    break;
                }
 

-             states[length++] = stateno;
+             states1[length++] = state->number;

            }
 
            }
 

-         if (!state_table[stateno]->consistent)
-           add_lookback_edge (stateno, *rulep, i);
+         if (!state->consistent)
+           add_lookback_edge (state, *rulep, i);

 
          length--;
          done = 0;
 
          length--;
          done = 0;


@@ -539,8 +446,7 @@ build_relations (void)
              /* JF added rp>=ritem &&   I hope to god its right! */
              if (rp >= ritem && ISVAR (*rp))
                {
              /* JF added rp>=ritem &&   I hope to god its right! */
              if (rp >= ritem && ISVAR (*rp))
                {

-                 stateno = states[--length];
-                 edge[nedges++] = map_goto (stateno, *rp);
+                 edge[nedges++] = map_goto (states1[--length], *rp);

                  if (nullable[*rp])
                    done = 0;
                }
                  if (nullable[*rp])
                    done = 0;
                }


@@ -558,7 +464,7 @@ build_relations (void)
     }
 
   XFREE (edge);
     }
 
   XFREE (edge);

-  XFREE (states);
+  XFREE (states1);

 
   includes = transpose (includes, ngotos);
 }
 
   includes = transpose (includes, ngotos);
 }


@@ -582,10 +488,10 @@ compute_FOLLOWS (void)
 static void
 compute_lookaheads (void)
 {
 static void
 compute_lookaheads (void)
 {

-  int i;
+  size_t i;

   shorts *sp;
 
   shorts *sp;
 

-  for (i = 0; i < state_table[nstates]->lookaheads; i++)
+  for (i = 0; i < nLA; i++)

     for (sp = lookback[i]; sp; sp = sp->next)
       {
        int size = LA (i + 1) - LA (i);
     for (sp = lookback[i]; sp; sp = sp->next)
       {
        int size = LA (i + 1) - LA (i);


@@ -595,7 +501,7 @@ compute_lookaheads (void)
       }
 
   /* Free LOOKBACK. */
       }
 
   /* Free LOOKBACK. */

-  for (i = 0; i < state_table[nstates]->lookaheads; i++)
+  for (i = 0; i < nLA; i++)

     LIST_FREE (shorts, lookback[i]);
 
   XFREE (lookback);
     LIST_FREE (shorts, lookback[i]);
 
   XFREE (lookback);


@@ -603,16 +509,83 @@ compute_lookaheads (void)
 }
 
 
 }
 
 

+/*--------------------------------------.
+| Initializing the lookaheads members.  |
+`--------------------------------------*/
+
+static void
+initialize_lookaheads (void)
+{
+  int i;
+  nLA = 0;
+  for (i = 0; i < nstates; i++)
+    {
+      int k;
+      int nlookaheads = 0;
+      reductions *rp = states[i]->reductions;
+      shifts *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->nreds > 1
+         || (rp->nreds == 1 && sp->nshifts && SHIFT_IS_SHIFT (sp, 0)))
+       nlookaheads += rp->nreds;
+      else
+       states[i]->consistent = 1;
+
+      for (k = 0; k < sp->nshifts; k++)
+       if (SHIFT_IS_ERROR (sp, k))
+         {
+           states[i]->consistent = 0;
+           break;
+         }
+
+      states[i]->nlookaheads = nlookaheads;
+      states[i]->lookaheadsp = nLA;
+      nLA += nlookaheads;
+    }
+}
+
+
+/*---------------------------------------.
+| Output the lookaheads for each state.  |
+`---------------------------------------*/
+
+static void
+lookaheads_print (FILE *out)
+{
+  int i, j, k;
+  fprintf (out, "Lookaheads: BEGIN\n");
+  for (i = 0; i < nstates; ++i)
+    {
+      fprintf (out, "State %d: %d lookaheads\n",
+              i, states[i]->nlookaheads);
+
+      for (j = 0; j < states[i]->nlookaheads; ++j)
+       for (k = 0; k < ntokens; ++k)
+         if (BITISSET (LA (states[i]->lookaheadsp + j), j))
+           fprintf (out, "   on %d (%s) -> rule %d\n",
+                    k, symbols[k]->tag,
+                    -LAruleno[states[i]->lookaheadsp + j] - 1);
+    }
+  fprintf (out, "Lookaheads: END\n");
+}
+

 void
 lalr (void)
 {
   tokensetsize = WORDSIZE (ntokens);
 
 void
 lalr (void)
 {
   tokensetsize = WORDSIZE (ntokens);
 

-  set_state_table ();
+  initialize_lookaheads ();

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

+
+  if (trace_flag)
+    lookaheads_print (stderr);

 }
 }