X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/a17e599f81825bc01cb237925f34ccc67b51a9a0..f9abaa2c4c5c77c5b6bdcfc0149c0af5adc8cc39:/src/conflicts.c

diff --git a/src/conflicts.c b/src/conflicts.c
index e26a7adf..e08256a1 100644
--- a/src/conflicts.c
+++ b/src/conflicts.c
@@ -1,5 +1,5 @@
 /* Find and resolve or report look-ahead conflicts for bison,
-   Copyright 1984, 1989, 1992, 2000, 2001 Free Software Foundation, Inc.
+   Copyright 1984, 1989, 1992, 2000, 2001, 2002 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
@@ -19,8 +19,10 @@
    02111-1307, USA.  */
 
 #include "system.h"
+#include "bitset.h"
 #include "complain.h"
 #include "getargs.h"
+#include "symtab.h"
 #include "files.h"
 #include "gram.h"
 #include "state.h"
@@ -29,22 +31,23 @@
 #include "reader.h"
 #include "LR0.h"
 
-errs **err_table = NULL;
 /* -1 stands for not specified. */
 int expected_conflicts = -1;
 static char *conflicts = NULL;
 
-static unsigned *shiftset = NULL;
-static unsigned *lookaheadset = NULL;
+static bitset shiftset;
+static bitset lookaheadset;
 
 
 static inline void
-log_resolution (int state, int LAno, int token, char *resolution)
+log_resolution (state_t *state, int LAno, int token, char *resolution)
 {
-  obstack_fgrow4 (&output_obstack,
-		  _("\
+  if (verbose_flag)
+    obstack_fgrow4 (&output_obstack,
+		    _("\
 Conflict in state %d between rule %d and token %s resolved as %s.\n"),
-		  state, LAruleno[LAno], tags[token], resolution);
+		    state->number, LAruleno[LAno], symbols[token]->tag,
+		    resolution);
 }
 
 
@@ -55,23 +58,28 @@ Conflict in state %d between rule %d and token %s resolved as %s.\n"),
 `------------------------------------------------------------------*/
 
 static void
-flush_shift (int state, int token)
+flush_shift (state_t *state, int token)
 {
-  shifts *shiftp;
-  int k, i;
+  shifts *shiftp = state->shifts;
+  int i;
+
+  bitset_reset (lookaheadset, token);
+  for (i = 0; i < shiftp->nshifts; i++)
+    if (!SHIFT_IS_DISABLED (shiftp, i) && SHIFT_SYMBOL (shiftp, i) == token)
+      SHIFT_DISABLE (shiftp, i);
+}
 
-  shiftp = state_table[state].shift_table;
 
-  if (shiftp)
-    {
-      k = shiftp->nshifts;
-      for (i = 0; i < k; i++)
-	{
-	  if (shiftp->shifts[i]
-	      && token == state_table[shiftp->shifts[i]].accessing_symbol)
-	    (shiftp->shifts[i]) = 0;
-	}
-    }
+/*-------------------------------------------------------------------.
+| Turn off the reduce recorded for the specified token for the       |
+| specified lookahead.  Used when we resolve a shift-reduce conflict |
+| in favor of the shift.                                             |
+`-------------------------------------------------------------------*/
+
+static void
+flush_reduce (int lookahead, int token)
+{
+  bitset_reset (LA[lookahead], token);
 }
 
 
@@ -83,168 +91,124 @@ flush_shift (int state, int token)
 `------------------------------------------------------------------*/
 
 static void
-resolve_sr_conflict (int state, int lookaheadnum)
+resolve_sr_conflict (state_t *state, int lookahead)
 {
   int i;
-  int mask;
-  unsigned *fp1;
-  unsigned *fp2;
-  int redprec;
-  errs *errp = ERRS_ALLOC (ntokens + 1);
-  short *errtokens = errp->errs;
-
   /* find the rule to reduce by to get precedence of reduction  */
-  redprec = rule_table[LAruleno[lookaheadnum]].prec;
+  int redprec = rules[LAruleno[lookahead]].prec;
+  errs *errp = errs_new (ntokens + 1);
+  errp->nerrs = 0;
 
-  mask = 1;
-  fp1 = LA (lookaheadnum);
-  fp2 = lookaheadset;
   for (i = 0; i < ntokens; i++)
-    {
-      if ((mask & *fp2 & *fp1) && sprec[i])
+    if (bitset_test (LA[lookahead], i)
+	&& bitset_test (lookaheadset, i)
+	&& symbols[i]->prec)
+      {
 	/* Shift-reduce conflict occurs for token number i
 	   and it has a precedence.
 	   The precedence of shifting is that of token i.  */
-	{
-	  if (sprec[i] < redprec)
+	if (symbols[i]->prec < redprec)
+	  {
+	    log_resolution (state, lookahead, i, _("reduce"));
+	    flush_shift (state, i);
+	  }
+	else if (symbols[i]->prec > redprec)
+	  {
+	    log_resolution (state, lookahead, i, _("shift"));
+	    flush_reduce (lookahead, i);
+	  }
+	else
+	  /* Matching precedence levels.
+	     For left association, keep only the reduction.
+	     For right association, keep only the shift.
+	     For nonassociation, keep neither.  */
+
+	  switch (symbols[i]->assoc)
 	    {
-	      log_resolution (state, lookaheadnum, i, _("reduce"));
-	      *fp2 &= ~mask;	/* flush the shift for this token */
+	    case right_assoc:
+	      log_resolution (state, lookahead, i, _("shift"));
+	      flush_reduce (lookahead, i);
+	      break;
+
+	    case left_assoc:
+	      log_resolution (state, lookahead, i, _("reduce"));
 	      flush_shift (state, i);
+	      break;
+
+	    case non_assoc:
+	      log_resolution (state, lookahead, i, _("an error"));
+	      flush_shift (state, i);
+	      flush_reduce (lookahead, i);
+	      /* Record an explicit error for this token.  */
+	      errp->errs[errp->nerrs++] = i;
+	      break;
 	    }
-	  else if (sprec[i] > redprec)
-	    {
-	      log_resolution (state, lookaheadnum, i, _("shift"));
-	      *fp1 &= ~mask;	/* flush the reduce for this token */
-	    }
-	  else
-	    {
-	      /* Matching precedence levels.
-	         For left association, keep only the reduction.
-	         For right association, keep only the shift.
-	         For nonassociation, keep neither.  */
-
-	      switch (sassoc[i])
-		{
-		case right_assoc:
-		  log_resolution (state, lookaheadnum, i, _("shift"));
-		  break;
-
-		case left_assoc:
-		  log_resolution (state, lookaheadnum, i, _("reduce"));
-		  break;
-
-		case non_assoc:
-		  log_resolution (state, lookaheadnum, i, _("an error"));
-		  break;
-		}
-
-	      if (sassoc[i] != right_assoc)
-		{
-		  *fp2 &= ~mask;	/* flush the shift for this token */
-		  flush_shift (state, i);
-		}
-	      if (sassoc[i] != left_assoc)
-		{
-		  *fp1 &= ~mask;	/* flush the reduce for this token */
-		}
-	      if (sassoc[i] == non_assoc)
-		{
-		  /* Record an explicit error for this token.  */
-		  *errtokens++ = i;
-		}
-	    }
-	}
-
-      mask <<= 1;
-      if (mask == 0)
-	{
-	  mask = 1;
-	  fp2++;
-	  fp1++;
-	}
-    }
-  errp->nerrs = errtokens - errp->errs;
-  if (errp->nerrs)
-    {
-      /* Some tokens have been explicitly made errors.  Allocate
-         a permanent errs structure for this state, to record them.  */
-      i = (char *) errtokens - (char *) errp;
-      err_table[state] = ERRS_ALLOC (i + 1);
-      bcopy (errp, err_table[state], i);
-    }
-  else
-    err_table[state] = 0;
+      }
+
+  /* Some tokens have been explicitly made errors.  Allocate a
+     permanent errs structure for this state, to record them.  */
+  state->errs = errs_dup (errp);
   free (errp);
 }
 
 
 static void
-set_conflicts (int state)
+set_conflicts (state_t *state)
 {
   int i, j;
   shifts *shiftp;
-  int symbol;
 
-  if (state_table[state].consistent)
+  if (state->consistent)
     return;
 
-  for (i = 0; i < tokensetsize; i++)
-    lookaheadset[i] = 0;
+  bitset_zero (lookaheadset);
 
-  shiftp = state_table[state].shift_table;
-  if (shiftp)
-    for (i = 0; i < shiftp->nshifts; i++)
-      {
-	symbol = state_table[shiftp->shifts[i]].accessing_symbol;
-	if (ISVAR (symbol))
-	  break;
-	SETBIT (lookaheadset, symbol);
-      }
+  shiftp = state->shifts;
+  for (i = 0; i < shiftp->nshifts && SHIFT_IS_SHIFT (shiftp, i); i++)
+    if (!SHIFT_IS_DISABLED (shiftp, i))
+      bitset_set (lookaheadset, SHIFT_SYMBOL (shiftp, i));
 
   /* Loop over all rules which require lookahead in this state.  First
      check for shift-reduce conflict, and try to resolve using
      precedence */
-  for (i = state_table[state].lookaheads;
-       i < state_table[state + 1].lookaheads;
-       ++i)
-    if (rule_table[LAruleno[i]].prec)
-      for (j = 0; j < tokensetsize; ++j)
-	if (LA (i)[j] & lookaheadset[j])
+  for (i = 0; i < state->nlookaheads; ++i)
+    if (rules[LAruleno[state->lookaheadsp + i]].prec)
+      for (j = 0; j < ntokens; ++j)
+	if (bitset_test (LA[state->lookaheadsp + i], j)
+	    && bitset_test (lookaheadset, j))
 	  {
-	    resolve_sr_conflict (state, i);
+	    resolve_sr_conflict (state, state->lookaheadsp + i);
 	    break;
 	  }
 
 
   /* Loop over all rules which require lookahead in this state.  Check
      for conflicts not resolved above.  */
-  for (i = state_table[state].lookaheads;
-       i < state_table[state + 1].lookaheads;
-       ++i)
+  for (i = 0; i < state->nlookaheads; ++i)
     {
-      for (j = 0; j < tokensetsize; ++j)
-	if (LA (i)[j] & lookaheadset[j])
-	  conflicts[state] = 1;
+      /* FIXME: Here, I need something like `bitset_disjoint_p'. */
+      for (j = 0; j < ntokens; ++j)
+	if (bitset_test (LA[state->lookaheadsp + i], j)
+	    && bitset_test (lookaheadset, j))
+	  conflicts[state->number] = 1;
 
-      for (j = 0; j < tokensetsize; ++j)
-	lookaheadset[j] |= LA (i)[j];
+      bitset_or (lookaheadset, lookaheadset, LA[state->lookaheadsp + i]);
     }
 }
 
 void
 solve_conflicts (void)
 {
-  int i;
+  size_t i;
 
   conflicts = XCALLOC (char, nstates);
-  shiftset = XCALLOC (unsigned, tokensetsize);
-  lookaheadset = XCALLOC (unsigned, tokensetsize);
-
-  err_table = XCALLOC (errs *, nstates);
+  shiftset = bitset_create (ntokens, BITSET_FIXED);
+  bitset_zero (shiftset);
+  lookaheadset = bitset_create (ntokens, BITSET_FIXED);
+  bitset_zero (lookaheadset);
 
   for (i = 0; i < nstates; i++)
-    set_conflicts (i);
+    set_conflicts (states[i]);
 }
 
 
@@ -253,72 +217,30 @@ solve_conflicts (void)
 `---------------------------------------------*/
 
 static int
-count_sr_conflicts (int state)
+count_sr_conflicts (state_t *state)
 {
   int i;
-  int k;
-  int mask;
-  shifts *shiftp;
-  unsigned *fp1;
-  unsigned *fp2;
-  unsigned *fp3;
-  int symbol;
-
   int src_count = 0;
+  shifts *shiftp = state->shifts;
 
-  shiftp = state_table[state].shift_table;
   if (!shiftp)
     return 0;
 
-  for (i = 0; i < tokensetsize; i++)
-    {
-      shiftset[i] = 0;
-      lookaheadset[i] = 0;
-    }
+  bitset_zero (lookaheadset);
+  bitset_zero (shiftset);
 
-  k = shiftp->nshifts;
-  for (i = 0; i < k; i++)
-    {
-      if (!shiftp->shifts[i])
-	continue;
-      symbol = state_table[shiftp->shifts[i]].accessing_symbol;
-      if (ISVAR (symbol))
-	break;
-      SETBIT (shiftset, symbol);
-    }
+  for (i = 0; i < shiftp->nshifts && SHIFT_IS_SHIFT (shiftp, i); i++)
+    if (!SHIFT_IS_DISABLED (shiftp, i))
+      bitset_set (shiftset, SHIFT_SYMBOL (shiftp, i));
 
-  k = state_table[state + 1].lookaheads;
-  fp3 = lookaheadset + tokensetsize;
+  for (i = 0; i < state->nlookaheads; ++i)
+    bitset_or (lookaheadset, lookaheadset, LA[state->lookaheadsp + i]);
 
-  for (i = state_table[state].lookaheads; i < k; i++)
-    {
-      fp1 = LA (i);
-      fp2 = lookaheadset;
+  bitset_and (lookaheadset, lookaheadset, shiftset);
 
-      while (fp2 < fp3)
-	*fp2++ |= *fp1++;
-    }
-
-  fp1 = shiftset;
-  fp2 = lookaheadset;
-
-  while (fp2 < fp3)
-    *fp2++ &= *fp1++;
-
-  mask = 1;
-  fp2 = lookaheadset;
   for (i = 0; i < ntokens; i++)
-    {
-      if (mask & *fp2)
-	src_count++;
-
-      mask <<= 1;
-      if (mask == 0)
-	{
-	  mask = 1;
-	  fp2++;
-	}
-    }
+    if (bitset_test (lookaheadset, i))
+      src_count++;
 
   return src_count;
 }
@@ -329,45 +251,24 @@ count_sr_conflicts (int state)
 `----------------------------------------------*/
 
 static int
-count_rr_conflicts (int state)
+count_rr_conflicts (state_t *state)
 {
   int i;
-  unsigned mask;
-  unsigned *baseword;
-
   int rrc_count = 0;
 
-  int m = state_table[state].lookaheads;
-  int n = state_table[state + 1].lookaheads;
-
-  if (n - m < 2)
+  if (state->nlookaheads < 2)
     return 0;
 
-  mask = 1;
-  baseword = LA (m);
   for (i = 0; i < ntokens; i++)
     {
-      unsigned *wordp = baseword;
-
       int count = 0;
       int j;
-      for (j = m; j < n; j++)
-	{
-	  if (mask & *wordp)
-	    count++;
-
-	  wordp += tokensetsize;
-	}
+      for (j = 0; j < state->nlookaheads; ++j)
+	if (bitset_test (LA[state->lookaheadsp + j], i))
+	  count++;
 
       if (count >= 2)
 	rrc_count++;
-
-      mask <<= 1;
-      if (mask == 0)
-	{
-	  mask = 1;
-	  baseword++;
-	}
     }
 
   return rrc_count;
@@ -420,13 +321,13 @@ void
 conflicts_output (FILE *out)
 {
   bool printed_sth = FALSE;
-  int i;
+  size_t i;
   for (i = 0; i < nstates; i++)
     if (conflicts[i])
       {
 	fprintf (out, _("State %d contains "), i);
-	fputs (conflict_report (count_sr_conflicts (i),
-				count_rr_conflicts (i)), out);
+	fputs (conflict_report (count_sr_conflicts (states[i]),
+				count_rr_conflicts (states[i])), out);
 	printed_sth = TRUE;
       }
   if (printed_sth)
@@ -441,7 +342,7 @@ conflicts_output (FILE *out)
 void
 conflicts_print (void)
 {
-  int i;
+  size_t i;
 
   /* Is the number of SR conflicts OK?  Either EXPECTED_CONFLICTS is
      not set, and then we want 0 SR, or else it is specified, in which
@@ -455,8 +356,8 @@ conflicts_print (void)
   for (i = 0; i < nstates; i++)
     if (conflicts[i])
       {
-	src_total += count_sr_conflicts (i);
-	rrc_total += count_rr_conflicts (i);
+	src_total += count_sr_conflicts (states[i]);
+	rrc_total += count_rr_conflicts (states[i]);
       }
 
   src_ok = src_total == (expected_conflicts == -1 ? 0 : expected_conflicts);
@@ -497,209 +398,10 @@ conflicts_print (void)
 }
 
 
-void
-print_reductions (FILE *out, int state)
-{
-  int i;
-  int j;
-  int symbol;
-  unsigned mask;
-  int m;
-  int n;
-  int default_LA;
-  int default_rule = 0;
-  int cmax;
-  int count;
-  shifts *shiftp;
-  errs *errp;
-  int nodefault = 0;
-
-  for (i = 0; i < tokensetsize; i++)
-    shiftset[i] = 0;
-
-  shiftp = state_table[state].shift_table;
-  if (shiftp)
-    for (i = 0; i < shiftp->nshifts; i++)
-      {
-	if (!shiftp->shifts[i])
-	  continue;
-	symbol = state_table[shiftp->shifts[i]].accessing_symbol;
-	if (ISVAR (symbol))
-	  break;
-	/* if this state has a shift for the error token,
-	   don't use a default rule.  */
-	if (symbol == error_token_number)
-	  nodefault = 1;
-	SETBIT (shiftset, symbol);
-      }
-
-  errp = err_table[state];
-  if (errp)
-    {
-      for (i = 0; i < errp->nerrs; i++)
-	{
-	  if (!errp->errs[i])
-	    continue;
-	  SETBIT (shiftset, errp->errs[i]);
-	}
-    }
-
-  m = state_table[state].lookaheads;
-  n = state_table[state + 1].lookaheads;
-
-  if (n - m == 1 && !nodefault)
-    {
-      int k;
-      default_rule = LAruleno[m];
-
-      for (k = 0; k < tokensetsize; ++k)
-	lookaheadset[k] = LA (m)[k] & shiftset[k];
-
-      for (i = 0; i < ntokens; i++)
-	if (BITISSET (lookaheadset, i))
-	  fprintf (out, _("    %-4s\t[reduce using rule %d (%s)]\n"),
-		   tags[i], default_rule,
-		   tags[rule_table[default_rule].lhs]);
-
-      fprintf (out, _("    $default\treduce using rule %d (%s)\n\n"),
-	       default_rule, tags[rule_table[default_rule].lhs]);
-    }
-  else if (n - m >= 1)
-    {
-      unsigned *fp1, *fp2, *fp3, *fp4;
-
-      cmax = 0;
-      default_LA = -1;
-      fp4 = lookaheadset + tokensetsize;
-
-      if (!nodefault)
-	for (i = m; i < n; i++)
-	  {
-	    fp1 = LA (i);
-	    fp2 = shiftset;
-	    fp3 = lookaheadset;
-
-	    while (fp3 < fp4)
-	      *fp3++ = *fp1++ & (~(*fp2++));
-
-	    count = 0;
-	    mask = 1;
-	    fp3 = lookaheadset;
-	    for (j = 0; j < ntokens; j++)
-	      {
-		if (mask & *fp3)
-		  count++;
-
-		mask <<= 1;
-		if (mask == 0)
-		  {
-		    mask = 1;
-		    fp3++;
-		  }
-	      }
-
-	    if (count > cmax)
-	      {
-		cmax = count;
-		default_LA = i;
-		default_rule = LAruleno[i];
-	      }
-
-	    fp2 = shiftset;
-	    fp3 = lookaheadset;
-
-	    while (fp3 < fp4)
-	      *fp2++ |= *fp3++;
-	  }
-
-      for (i = 0; i < tokensetsize; i++)
-	shiftset[i] = 0;
-
-      if (shiftp)
-	{
-	  for (i = 0; i < shiftp->nshifts; i++)
-	    {
-	      if (!shiftp->shifts[i])
-		continue;
-	      symbol = state_table[shiftp->shifts[i]].accessing_symbol;
-	      if (ISVAR (symbol))
-		break;
-	      SETBIT (shiftset, symbol);
-	    }
-	}
-
-      mask = 1;
-      fp1 = LA (m);
-      fp2 = shiftset;
-      for (i = 0; i < ntokens; i++)
-	{
-	  int defaulted = 0;
-
-	  if (mask & *fp2)
-	    count = 1;
-	  else
-	    count = 0;
-
-	  fp3 = fp1;
-	  for (j = m; j < n; j++)
-	    {
-	      if (mask & *fp3)
-		{
-		  if (count == 0)
-		    {
-		      if (j != default_LA)
-			fprintf (out,
-				 _("    %-4s\treduce using rule %d (%s)\n"),
-				 tags[i],
-				 LAruleno[j],
-				 tags[rule_table[LAruleno[j]].lhs]);
-		      else
-			defaulted = 1;
-
-		      count++;
-		    }
-		  else
-		    {
-		      if (defaulted)
-			fprintf (out,
-				 _("    %-4s\treduce using rule %d (%s)\n"),
-				 tags[i],
-				 LAruleno[default_LA],
-				 tags[rule_table[LAruleno[default_LA]].lhs]);
-		      defaulted = 0;
-		      fprintf (out,
-			       _("    %-4s\t[reduce using rule %d (%s)]\n"),
-			       tags[i],
-			       LAruleno[j],
-			       tags[rule_table[LAruleno[j]].lhs]);
-		    }
-		}
-
-	      fp3 += tokensetsize;
-	    }
-
-	  mask <<= 1;
-	  if (mask == 0)
-	    {
-	      mask = 1;
-	      /* We tried incrementing just fp1, and just fp2; both seem wrong.
-	         It seems necessary to increment both in sync.  */
-	      fp1++;
-	      fp2++;
-	    }
-	}
-
-      if (default_LA >= 0)
-	fprintf (out, _("    $default\treduce using rule %d (%s)\n"),
-		 default_rule, tags[rule_table[default_rule].lhs]);
-    }
-}
-
-
 void
 free_conflicts (void)
 {
   XFREE (conflicts);
-  XFREE (shiftset);
-  XFREE (lookaheadset);
+  bitset_free (shiftset);
+  bitset_free (lookaheadset);
 }