X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/4d4f699ca481fbb1d255ade0561ad6c7a89949ae..e91ff6ce3d2653b41265591dafd4bdb32ae114c2:/src/lalr.c?ds=sidebyside

diff --git a/src/lalr.c b/src/lalr.c
index c2554dcf..643f8fd9 100644
--- a/src/lalr.c
+++ b/src/lalr.c
@@ -1,5 +1,6 @@
 /* Compute look-ahead criteria for bison,
-   Copyright 1984, 1986, 1989, 2000, 2001  Free Software Foundation, Inc.
+   Copyright (C) 1984, 1986, 1989, 2000, 2001, 2002
+   Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
@@ -24,52 +25,58 @@
    tokens they accept.  */
 
 #include "system.h"
+#include "bitset.h"
+#include "bitsetv.h"
+#include "quotearg.h"
+#include "symtab.h"
+#include "gram.h"
+#include "reader.h"
 #include "types.h"
 #include "LR0.h"
-#include "gram.h"
 #include "complain.h"
 #include "lalr.h"
 #include "nullable.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;
-
-int tokensetsize;
-short *LAruleno;
-unsigned *LA;
+/* All the decorated states, indexed by the state number.  */
+state_t **states = NULL;
 
-short *goto_map;
-short *from_state;
-short *to_state;
+rule_t **LArule = NULL;
+bitsetv LA = NULL;
+size_t nLA;
 
-extern void berror PARAMS ((const char *));
-
-static int infinity;
 static int ngotos;
+short *goto_map = NULL;
+short *from_state = NULL;
+short *to_state = NULL;
 
 /* And for the famous F variable, which name is so descriptive that a
    comment is hardly needed.  <grin>.  */
-static unsigned *F = NULL;
-#define F(Rule)  (F + (Rule) * tokensetsize)
+static bitsetv F = NULL;
 
 static short **includes;
 static shorts **lookback;
+
+
+/*---------------------------------------------------------------.
+| digraph & traverse.                                            |
+|                                                                |
+| The following variables are used as common storage between the |
+| two.                                                           |
+`---------------------------------------------------------------*/
+
 static short **R;
 static short *INDEX;
 static short *VERTICES;
 static int top;
-
+static int infinity;
 
 static void
 traverse (int i)
 {
   int j;
-  size_t k;
   int height;
-  size_t size = F (i + 1) - F(i);
 
   VERTICES[++top] = i;
   INDEX[i] = height = top;
@@ -83,8 +90,7 @@ traverse (int i)
 	if (INDEX[i] > INDEX[R[i][j]])
 	  INDEX[i] = INDEX[R[i][j]];
 
-	for (k = 0; k < size; ++k)
-	  F (i)[k] |= F (R[i][j])[k];
+	bitset_or (F[i], F[i], F[R[i][j]]);
       }
 
   if (INDEX[i] == height)
@@ -96,8 +102,7 @@ traverse (int i)
 	if (i == j)
 	  break;
 
-	for (k = 0; k < size; ++k)
-	  F (i)[k] = F (j)[k];
+	bitset_copy (F[j], F[i]);
       }
 }
 
@@ -126,192 +131,79 @@ 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);
-
-  {
-    core *sp;
-    for (sp = first_state; sp; sp = sp->next)
-      {
-	state_table[sp->number].state = sp;
-	state_table[sp->number].accessing_symbol = sp->accessing_symbol;
-      }
-  }
-
-  {
-    shifts *sp;
-    for (sp = first_shift; sp; sp = sp->next)
-      state_table[sp->number].shift_table = sp;
-  }
-
-  {
-    reductions *rp;
-    for (rp = first_reduction; rp; rp = rp->next)
-      state_table[rp->number].reduction_table = rp;
-  }
-
-  /* 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].reduction_table;
-	shifts *sp = state_table[i].shift_table;
-
-	state_table[i].lookaheads = count;
-
-	if (rp
-	    && (rp->nreds > 1
-		|| (sp && !ISVAR (state_table[sp->shifts[0]].accessing_symbol))))
-	  count += rp->nreds;
-	else
-	  state_table[i].consistent = 1;
-
-	if (sp)
-	  for (k = 0; k < sp->nshifts; k++)
-	    if (state_table[sp->shifts[k]].accessing_symbol
-		== error_token_number)
-	      {
-		state_table[i].consistent = 0;
-		break;
-	      }
-      }
-     state_table[nstates].lookaheads = count;
-  }
-}
-
-
-/*------------------------------------------.
-| Return the size of the longest rule RHS.  |
-`------------------------------------------*/
-
-static size_t
-maxrhs (void)
-{
-  short *itemp;
-  int length;
-  int max;
-
-  length = 0;
-  max = 0;
-  for (itemp = ritem; *itemp; itemp++)
-    {
-      if (*itemp > 0)
-	{
-	  length++;
-	}
-      else
-	{
-	  if (length > max)
-	    max = length;
-	  length = 0;
-	}
-    }
-
-  return max;
-}
-
-
 static void
 initialize_LA (void)
 {
-  int i;
+  size_t i;
   int j;
-  short *np;
-  reductions *rp;
+  rule_t **np;
 
-  size_t nLA = state_table[nstates].lookaheads;
+  /* Avoid having to special case 0.  */
   if (!nLA)
     nLA = 1;
 
-  LA = XCALLOC (unsigned, nLA * tokensetsize);
-  LAruleno = XCALLOC (short, nLA);
+  LA = bitsetv_create (nLA, ntokens, BITSET_FIXED);
+  LArule = XCALLOC (rule_t *, nLA);
   lookback = XCALLOC (shorts *, nLA);
 
-  np = LAruleno;
+  np = LArule;
   for (i = 0; i < nstates; i++)
-    if (!state_table[i].consistent)
-      if ((rp = state_table[i].reduction_table))
-	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++ = &rules[states[i]->reductions->rules[j]];
 }
 
 
 static void
 set_goto_map (void)
 {
-  shifts *sp;
+  size_t state;
   int i;
-  int symbol;
-  int k;
   short *temp_map;
-  int state2;
-  int state1;
 
   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 (state = 0; state < nstates; ++state)
     {
-      for (i = sp->nshifts - 1; i >= 0; i--)
+      shifts *sp = states[state]->shifts;
+      for (i = sp->nshifts - 1; i >= 0 && SHIFT_IS_GOTO (sp, i); --i)
 	{
-	  symbol = state_table[sp->shifts[i]].accessing_symbol;
-
-	  if (ISTOKEN (symbol))
-	    break;
-
-	  if (ngotos == MAXSHORT)
-	    fatal (_("too many gotos (max %d)"), MAXSHORT);
+	  if (ngotos == SHRT_MAX)
+	    fatal (_("too many gotos (max %d)"), SHRT_MAX);
 
 	  ngotos++;
-	  goto_map[symbol]++;
+	  goto_map[SHIFT_SYMBOL (sp, i)]++;
 	}
     }
 
-  k = 0;
-  for (i = ntokens; i < nsyms; i++)
-    {
-      temp_map[i] = k;
-      k += goto_map[i];
-    }
+  {
+    int 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);
 
-  for (sp = first_shift; sp; sp = sp->next)
+  for (state = 0; state < nstates; ++state)
     {
-      state1 = sp->number;
-      for (i = sp->nshifts - 1; i >= 0; i--)
+      shifts *sp = states[state]->shifts;
+      for (i = sp->nshifts - 1; i >= 0 && SHIFT_IS_GOTO (sp, i); --i)
 	{
-	  state2 = sp->shifts[i];
-	  symbol = state_table[state2].accessing_symbol;
-
-	  if (ISTOKEN (symbol))
-	    break;
-
-	  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];
 	}
     }
 
@@ -325,7 +217,7 @@ set_goto_map (void)
 `----------------------------------------------------------*/
 
 static int
-map_goto (int state, int symbol)
+map_goto (int state, token_number_t symbol)
 {
   int high;
   int low;
@@ -362,38 +254,30 @@ initialize_F (void)
 
   int i;
 
-  F = XCALLOC (unsigned, ngotos * tokensetsize);
+  F = bitsetv_create (ngotos, ntokens, BITSET_FIXED);
 
   for (i = 0; i < ngotos; i++)
     {
       int stateno = to_state[i];
-      shifts *sp = state_table[stateno].shift_table;
+      shifts *sp = states[stateno]->shifts;
 
-      if (sp)
-	{
-	  int j;
-	  for (j = 0; j < sp->nshifts; j++)
-	    {
-	      int symbol = state_table[sp->shifts[j]].accessing_symbol;
-	      if (ISVAR (symbol))
-		break;
-	      SETBIT (F + i * tokensetsize, symbol);
-	    }
+      int j;
+      for (j = 0; j < sp->nshifts && SHIFT_IS_SHIFT (sp, j); j++)
+	bitset_set (F[i], SHIFT_SYMBOL (sp, j));
 
-	  for (; j < sp->nshifts; j++)
-	    {
-	      int symbol = state_table[sp->shifts[j]].accessing_symbol;
-	      if (nullable[symbol])
-		edge[nedges++] = map_goto (stateno, symbol);
-	    }
+      for (; j < sp->nshifts; j++)
+	{
+	  token_number_t symbol = SHIFT_SYMBOL (sp, j);
+	  if (nullable[symbol])
+	    edge[nedges++] = map_goto (stateno, symbol);
+	}
 
-	  if (nedges)
-	    {
-	      reads[i] = XCALLOC (short, nedges + 1);
-	      shortcpy (reads[i], edge, nedges);
-	      reads[i][nedges] = -1;
-	      nedges = 0;
-	    }
+      if (nedges)
+	{
+	  reads[i] = XCALLOC (short, nedges + 1);
+	  memcpy (reads[i], edge, nedges * sizeof (edge[0]));
+	  reads[i][nedges] = -1;
+	  nedges = 0;
 	}
     }
 
@@ -408,77 +292,106 @@ initialize_F (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 k;
-  int found;
   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 (LArule[state->lookaheadsp + i]->number == ruleno)
+      break;
 
-  assert (found);
+  assert (LArule[state->lookaheadsp + i]->number == ruleno);
 
   sp = XCALLOC (shorts, 1);
-  sp->next = lookback[i];
+  sp->next = lookback[state->lookaheadsp + i];
   sp->value = gotono;
-  lookback[i] = sp;
+  lookback[state->lookaheadsp + i] = sp;
 }
 
 
-static short **
-transpose (short **R_arg, int n)
+static void
+matrix_print (FILE *out, short **matrix, int n)
 {
-  short **new_R;
-  short **temp_R;
-  short *nedges;
-  int i;
+  int i, j;
+
+  for (i = 0; i < n; ++i)
+    {
+      fprintf (out, "%3d: ", i);
+      if (matrix[i])
+	for (j = 0; matrix[i][j] != -1; ++j)
+	  fprintf (out, "%3d ", matrix[i][j]);
+      fputc ('\n', out);
+    }
+  fputc ('\n', out);
+}
 
-  nedges = XCALLOC (short, n);
+/*-------------------------------------------------------------------.
+| Return the transpose of R_ARG, of size N.  Destroy R_ARG, as it is |
+| replaced with the result.                                          |
+|                                                                    |
+| R_ARG[I] is NULL or a -1 terminated list of numbers.               |
+|                                                                    |
+| RESULT[NUM] is NULL or the -1 terminated list of the I such as NUM |
+| is in R_ARG[I].                                                    |
+`-------------------------------------------------------------------*/
 
-  for (i = 0; i < n; i++)
+static short **
+transpose (short **R_arg, int n)
+{
+  /* The result. */
+  short **new_R = XCALLOC (short *, n);
+  /* END_R[I] -- next entry of NEW_R[I]. */
+  short **end_R = XCALLOC (short *, n);
+  /* NEDGES[I] -- total size of NEW_R[I]. */
+  short *nedges = XCALLOC (short, n);
+  int i, j;
+
+  if (trace_flag)
     {
-      short *sp = R_arg[i];
-      if (sp)
-	{
-	  while (*sp >= 0)
-	    nedges[*sp++]++;
-	}
+      fputs ("transpose: input\n", stderr);
+      matrix_print (stderr, R_arg, n);
     }
 
-  new_R = XCALLOC (short *, n);
-  temp_R = XCALLOC (short *, n);
+  /* Count. */
+  for (i = 0; i < n; i++)
+    if (R_arg[i])
+      for (j = 0; R_arg[i][j] >= 0; ++j)
+	++nedges[R_arg[i][j]];
 
+  /* Allocate. */
   for (i = 0; i < n; i++)
     if (nedges[i] > 0)
       {
 	short *sp = XCALLOC (short, nedges[i] + 1);
-	new_R[i] = sp;
-	temp_R[i] = sp;
 	sp[nedges[i]] = -1;
+	new_R[i] = sp;
+	end_R[i] = sp;
       }
 
-  XFREE (nedges);
+  /* Store. */
+  for (i = 0; i < n; i++)
+    if (R_arg[i])
+      for (j = 0; R_arg[i][j] >= 0; ++j)
+	{
+	  *end_R[R_arg[i][j]] = i;
+	  ++end_R[R_arg[i][j]];
+	}
+
+  free (nedges);
+  free (end_R);
 
+  /* Free the input: it is replaced with the result. */
   for (i = 0; i < n; i++)
+    XFREE (R_arg[i]);
+  free (R_arg);
+
+  if (trace_flag)
     {
-      short *sp = R_arg[i];
-      if (sp)
-	while (*sp >= 0)
-	  *temp_R[*sp++]++ = i;
+      fputs ("transpose: output\n", stderr);
+      matrix_print (stderr, new_R, n);
     }
 
-  XFREE (temp_R);
-
   return new_R;
 }
 
@@ -486,52 +399,43 @@ transpose (short **R_arg, int n)
 static void
 build_relations (void)
 {
+  short *edge = XCALLOC (short, ngotos + 1);
+  short *states1 = XCALLOC (short, ritem_longest_rhs () + 1);
   int i;
-  int j;
-  short *rulep;
-  short *rp;
-  int nedges;
-  int done;
-  int state1;
-  int stateno;
-  int symbol1;
-  short *edge;
-  short *states;
-  short **new_includes;
 
   includes = XCALLOC (short *, ngotos);
-  edge = XCALLOC (short, ngotos + 1);
-  states = XCALLOC (short, maxrhs () + 1);
 
   for (i = 0; i < ngotos; i++)
     {
-      nedges = 0;
-      state1 = from_state[i];
-      symbol1 = state_table[to_state[i]].accessing_symbol;
+      int nedges = 0;
+      token_number_t symbol1 = states[to_state[i]]->accessing_symbol;
+      short *rulep;
 
       for (rulep = derives[symbol1]; *rulep > 0; rulep++)
 	{
+	  int done;
 	  int length = 1;
-	  states[0] = state1;
-	  stateno = state1;
+	  item_number_t *rp;
+	  state_t *state = states[from_state[i]];
+	  states1[0] = state->number;
 
-	  for (rp = ritem + rule_table[*rulep].rhs; *rp > 0; rp++)
+	  for (rp = rules[*rulep].rhs; *rp >= 0; rp++)
 	    {
-	      int symbol2 = *rp;
-	      shifts *sp = state_table[stateno].shift_table;
-
+	      shifts *sp = state->shifts;
+	      int j;
 	      for (j = 0; j < sp->nshifts; j++)
 		{
-		  stateno = sp->shifts[j];
-		  if (state_table[stateno].accessing_symbol == symbol2)
+		  state = states[sp->shifts[j]];
+		  if (state->accessing_symbol
+		      == item_number_as_token_number (*rp))
 		    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;
@@ -542,8 +446,9 @@ build_relations (void)
 	      /* JF added rp>=ritem &&   I hope to god its right! */
 	      if (rp >= ritem && ISVAR (*rp))
 		{
-		  stateno = states[--length];
-		  edge[nedges++] = map_goto (stateno, *rp);
+		  /* Downcasting from item_number_t to token_number_t. */
+		  edge[nedges++] = map_goto (states1[--length],
+					     item_number_as_token_number (*rp));
 		  if (nullable[*rp])
 		    done = 0;
 		}
@@ -552,6 +457,7 @@ build_relations (void)
 
       if (nedges)
 	{
+	  int j;
 	  includes[i] = XCALLOC (short, nedges + 1);
 	  for (j = 0; j < nedges; j++)
 	    includes[i][j] = edge[j];
@@ -559,16 +465,10 @@ build_relations (void)
 	}
     }
 
-  new_includes = transpose (includes, ngotos);
-
-  for (i = 0; i < ngotos; i++)
-    XFREE (includes[i]);
-  XFREE (includes);
-
-  includes = new_includes;
-
   XFREE (edge);
-  XFREE (states);
+  XFREE (states1);
+
+  includes = transpose (includes, ngotos);
 }
 
 
@@ -590,37 +490,98 @@ compute_FOLLOWS (void)
 static void
 compute_lookaheads (void)
 {
-  int i;
+  size_t i;
   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)
-      {
-	unsigned *fp1 = LA (i);
-	unsigned *fp2 = F (sp->value);
-	while (fp1 < LA (i + 1))
-	  *fp1++ |= *fp2++;
-      }
+      bitset_or (LA[i], LA[i], F[sp->value]);
 
   /* Free LOOKBACK. */
-  for (i = 0; i < state_table[nstates].lookaheads; i++)
+  for (i = 0; i < nLA; i++)
     LIST_FREE (shorts, lookback[i]);
 
   XFREE (lookback);
-  XFREE (F);
+  bitsetv_free (F);
 }
 
 
+/*--------------------------------------.
+| Initializing the lookaheads members.  |
+`--------------------------------------*/
+
+static void
+initialize_lookaheads (void)
+{
+  size_t 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)
+{
+  size_t i;
+  int 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 (bitset_test (LA[states[i]->lookaheadsp + j], k))
+	    fprintf (out, "   on %d (%s) -> rule %d\n",
+		     k, quotearg_style (escape_quoting_style, symbols[k]->tag),
+		     LArule[states[i]->lookaheadsp + j]->number - 1);
+    }
+  fprintf (out, "Lookaheads: END\n");
+}
+
 void
 lalr (void)
 {
-  tokensetsize = WORDSIZE (ntokens);
-
-  set_state_table ();
+  initialize_lookaheads ();
   initialize_LA ();
   set_goto_map ();
   initialize_F ();
   build_relations ();
   compute_FOLLOWS ();
   compute_lookaheads ();
+
+  if (trace_flag)
+    lookaheads_print (stderr);
 }