X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/ceed8467b7db3615d3c9bfa9f3e5525d54c6a161..f377f69fec28013c79db4efe12bbb9d48987fb2c:/src/conflicts.c

diff --git a/src/conflicts.c b/src/conflicts.c
index 6b9cad07..24f27cc8 100644
--- a/src/conflicts.c
+++ b/src/conflicts.c
@@ -1,5 +1,6 @@
 /* Find and resolve or report look-ahead conflicts for bison,
-   Copyright (C) 1984, 1989, 1992, 2000 Free Software Foundation, Inc.
+   Copyright (C) 1984, 1989, 1992, 2000, 2001, 2002
+   Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
@@ -19,729 +20,532 @@
    02111-1307, USA.  */
 
 #include "system.h"
+#include "bitset.h"
+#include "complain.h"
 #include "getargs.h"
-#include "alloc.h"
+#include "symtab.h"
 #include "files.h"
 #include "gram.h"
 #include "state.h"
-
-
-extern char **tags;
-extern int tokensetsize;
-extern char *consistent;
-extern short *accessing_symbol;
-extern shifts **shift_table;
-extern unsigned *LA;
-extern short *LAruleno;
-extern short *lookaheads;
-extern int fixed_outfiles;
-
-extern void initialize_conflicts PARAMS((void));
-extern void conflict_log PARAMS((void));
-extern void verbose_conflict_log PARAMS((void));
-extern void print_reductions PARAMS((int));
-extern void finalize_conflicts PARAMS((void));
-
-static void set_conflicts PARAMS((int));
-static void resolve_sr_conflict PARAMS((int, int));
-static void flush_shift PARAMS((int, int));
-static void log_resolution PARAMS((int, int, int, char *));
-static void total_conflicts PARAMS((void));
-static void count_sr_conflicts PARAMS((int));
-static void count_rr_conflicts PARAMS((int));
-
-char any_conflicts;
-errs **err_table;
-int expected_conflicts;
-static char *conflicts;
-
-
-static unsigned *shiftset;
-static unsigned *lookaheadset;
-static int src_total;
-static int rrc_total;
-static int src_count;
-static int rrc_count;
-
-
-void
-initialize_conflicts (void)
+#include "lalr.h"
+#include "conflicts.h"
+#include "reader.h"
+#include "LR0.h"
+
+/* -1 stands for not specified. */
+int expected_conflicts = -1;
+static char *conflicts = NULL;
+struct obstack solved_conflicts_obstack;
+
+static bitset shiftset;
+static bitset lookaheadset;
+
+
+
+enum conflict_resolution_e
+  {
+    shift_resolution,
+    reduce_resolution,
+    left_resolution,
+    right_resolution,
+    nonassoc_resolution
+  };
+
+
+/*----------------------------------------------------------------.
+| Explain how an SR conflict between TOKEN and RULE was resolved: |
+| RESOLUTION.                                                     |
+`----------------------------------------------------------------*/
+
+static inline void
+log_resolution (rule_t *rule, symbol_number_t token,
+		enum conflict_resolution_e resolution)
 {
-  register int i;
-/*  register errs *sp; JF unused */
-
-  conflicts = NEW2(nstates, char);
-  shiftset = NEW2(tokensetsize, unsigned);
-  lookaheadset = NEW2(tokensetsize, unsigned);
-
-  err_table = NEW2(nstates, errs *);
-
-  any_conflicts = 0;
-
-  for (i = 0; i < nstates; i++)
-    set_conflicts(i);
-}
-
-
-static void
-set_conflicts (int state)
-{
-  register int i;
-  register int k;
-  register shifts *shiftp;
-  register unsigned *fp2;
-  register unsigned *fp3;
-  register unsigned *fp4;
-  register unsigned *fp1;
-  register int symbol;
-
-  if (consistent[state]) return;
-
-  for (i = 0; i < tokensetsize; i++)
-    lookaheadset[i] = 0;
-
-  shiftp = shift_table[state];
-  if (shiftp)
+  if (report_flag & report_solved_conflicts)
     {
-      k = shiftp->nshifts;
-      for (i = 0; i < k; i++)
+      /* The description of the resolution. */
+      switch (resolution)
 	{
-	  symbol = accessing_symbol[shiftp->shifts[i]];
-	  if (ISVAR(symbol)) break;
-	  SETBIT(lookaheadset, symbol);
+	case shift_resolution:
+	case right_resolution:
+	  obstack_fgrow2 (&solved_conflicts_obstack,
+			  _("\
+    Conflict between rule %d and token %s resolved as shift"),
+			  rule->number,
+			  symbols[token]->tag);
+	  break;
+	case reduce_resolution:
+	case left_resolution:
+	  obstack_fgrow2 (&solved_conflicts_obstack,
+			  _("\
+    Conflict between rule %d and token %s resolved as reduce"),
+			  rule->number,
+			  symbols[token]->tag);
+	  break;
+	case nonassoc_resolution:
+	  obstack_fgrow2 (&solved_conflicts_obstack,
+			  _("\
+    Conflict between rule %d and token %s resolved as an error"),
+			  rule->number,
+			  symbols[token]->tag);
+	  break;
 	}
-    }
 
-  k = lookaheads[state + 1];
-  fp4 = lookaheadset + tokensetsize;
-
-  /* loop over all rules which require lookahead in this state */
-  /* first check for shift-reduce conflict, and try to resolve using precedence  */
-
-  for (i = lookaheads[state]; i < k; i++)
-    if (rprec[LAruleno[i]])
-      {
-	fp1 = LA + i * tokensetsize;
-	fp2 = fp1;
-	fp3 = lookaheadset;
+      /* The reason. */
+      switch (resolution)
+	{
+	case shift_resolution:
+	  obstack_fgrow2 (&solved_conflicts_obstack,
+			  " (%s < %s)",
+			  rule->prec->tag,
+			  symbols[token]->tag);
+	  break;
+
+	case reduce_resolution:
+	  obstack_fgrow2 (&solved_conflicts_obstack,
+			  " (%s < %s)",
+			  symbols[token]->tag,
+			  rule->prec->tag);
+	  break;
+
+	case left_resolution:
+	  obstack_fgrow1 (&solved_conflicts_obstack,
+			  " (%%left %s)",
+			  symbols[token]->tag);
+	  break;
+
+	case right_resolution:
+	  obstack_fgrow1 (&solved_conflicts_obstack,
+			  " (%%right %s)",
+			  symbols[token]->tag);
+	  break;
+	case nonassoc_resolution:
+	  obstack_fgrow1 (&solved_conflicts_obstack,
+			  " (%%nonassoc %s)",
+			  symbols[token]->tag);
+	  break;
+	}
+      obstack_sgrow (&solved_conflicts_obstack, ".\n");
+    }
+}
 
-	while (fp3 < fp4)
-	  {
-	    if (*fp2++ & *fp3++)
-	      {
-		resolve_sr_conflict(state, i);
-		break;
-	      }
-	  }
-      }
 
-  /* loop over all rules which require lookahead in this state */
-  /* Check for conflicts not resolved above.  */
+/*------------------------------------------------------------------.
+| Turn off the shift recorded for the specified token in the        |
+| specified state.  Used when we resolve a shift-reduce conflict in |
+| favor of the reduction.                                           |
+`------------------------------------------------------------------*/
 
-  for (i = lookaheads[state]; i < k; i++)
-    {
-      fp1 = LA + i * tokensetsize;
-      fp2 = fp1;
-      fp3 = lookaheadset;
+static void
+flush_shift (state_t *state, int token)
+{
+  transitions_t *transitions = state->transitions;
+  int i;
+
+  bitset_reset (lookaheadset, token);
+  for (i = 0; i < transitions->num; i++)
+    if (!TRANSITION_IS_DISABLED (transitions, i)
+	&& TRANSITION_SYMBOL (transitions, i) == token)
+      TRANSITION_DISABLE (transitions, i);
+}
 
-      while (fp3 < fp4)
-	{
-	  if (*fp2++ & *fp3++)
-	    {
-	      conflicts[state] = 1;
-	      any_conflicts = 1;
-	    }
-	}
 
-      fp2 = fp1;
-      fp3 = lookaheadset;
+/*-------------------------------------------------------------------.
+| 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.                                             |
+`-------------------------------------------------------------------*/
 
-      while (fp3 < fp4)
-	*fp3++ |= *fp2++;
-    }
+static void
+flush_reduce (bitset lookaheads, int token)
+{
+  bitset_reset (lookaheads, token);
 }
 
 
-
-/* Attempt to resolve shift-reduce conflict for one rule
-by means of precedence declarations.
-It has already been checked that the rule has a precedence.
-A conflict is resolved by modifying the shift or reduce tables
-so that there is no longer a conflict.  */
+/*------------------------------------------------------------------.
+| Attempt to resolve shift-reduce conflict for one rule by means of |
+| precedence declarations.  It has already been checked that the    |
+| rule has a precedence.  A conflict is resolved by modifying the   |
+| shift or reduce tables so that there is no longer a conflict.     |
+|                                                                   |
+| LOOKAHEAD is the number of the lookahead bitset to consider.      |
+|                                                                   |
+| ERRS can be used to store discovered explicit errors.             |
+`------------------------------------------------------------------*/
 
 static void
-resolve_sr_conflict (int state, int lookaheadnum)
+resolve_sr_conflict (state_t *state, int ruleno,
+		     symbol_t **errs)
 {
-  register int i;
-  register int mask;
-  register unsigned *fp1;
-  register unsigned *fp2;
-  register int redprec;
-  errs *errp = (errs *) xmalloc (sizeof(errs) + ntokens * sizeof(short));
-  short *errtokens = errp->errs;
-
-  /* find the rule to reduce by to get precedence of reduction  */
-  redprec = rprec[LAruleno[lookaheadnum]];
-
-  mask = 1;
-  fp1 = LA + lookaheadnum * tokensetsize;
-  fp2 = lookaheadset;
+  symbol_number_t i;
+  reductions_t *reds = state->reductions;
+  /* Find the rule to reduce by to get precedence of reduction.  */
+  rule_t *redrule = reds->rules[ruleno];
+  int redprec = redrule->prec->prec;
+  bitset lookaheads = reds->lookaheads[ruleno];
+  int nerrs = 0;
+
   for (i = 0; i < ntokens; i++)
-    {
-      if ((mask & *fp2 & *fp1) && sprec[i])
+    if (bitset_test (lookaheads, 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 (verboseflag) log_resolution(state, lookaheadnum, i, _("reduce"));
-	      *fp2 &= ~mask;  /* flush the shift for this token */
-	      flush_shift(state, i);
-	    }
-	  else if (sprec[i] > redprec)
-	    {
-	      if (verboseflag) log_resolution(state, lookaheadnum, i, _("shift"));
-	      *fp1 &= ~mask;  /* flush the reduce for this token */
-	    }
-	  else
+	if (symbols[i]->prec < redprec)
+	  {
+	    log_resolution (redrule, i, reduce_resolution);
+	    flush_shift (state, i);
+	  }
+	else if (symbols[i]->prec > redprec)
+	  {
+	    log_resolution (redrule, i, shift_resolution);
+	    flush_reduce (lookaheads, 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)
 	    {
-	      /* 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:
-	          if (verboseflag) log_resolution(state, lookaheadnum, i, _("shift"));
-		  break;
-
-		case LEFT_ASSOC:
-	          if (verboseflag) log_resolution(state, lookaheadnum, i, _("reduce"));
-		  break;
-
-		case NON_ASSOC:
-	          if (verboseflag) 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;
-		}
+	    case right_assoc:
+	      log_resolution (redrule, i, right_resolution);
+	      flush_reduce (lookaheads, i);
+	      break;
+
+	    case left_assoc:
+	      log_resolution (redrule, i, left_resolution);
+	      flush_shift (state, i);
+	      break;
+
+	    case non_assoc:
+	      log_resolution (redrule, i, nonassoc_resolution);
+	      flush_shift (state, i);
+	      flush_reduce (lookaheads, i);
+	      /* Record an explicit error for this token.  */
+	      errs[nerrs++] = symbols[i];
+	      break;
+
+	    case undef_assoc:
+	      assert (symbols[i]->assoc != undef_assoc);
+	      break;
 	    }
-	}
+      }
 
-      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.  */
+  state_errs_set (state, nerrs, errs);
+
+  if (obstack_object_size (&solved_conflicts_obstack))
     {
-      /* 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 *) xmalloc ((unsigned int)i);
-      bcopy (errp, err_table[state], i);
+      obstack_1grow (&solved_conflicts_obstack, '\0');
+      state->solved_conflicts = obstack_finish (&solved_conflicts_obstack);
     }
-  else
-    err_table[state] = 0;
-  free(errp);
 }
 
 
-
-/* turn off the shift recorded for the specified token in the specified state.
-Used when we resolve a shift-reduce conflict in favor of the reduction.  */
+/*-------------------------------------------------------------------.
+| Solve the S/R conflicts of STATE using the                         |
+| precedence/associativity, and flag it inconsistent if it still has |
+| conflicts.  ERRS can be used as storage to compute the list of     |
+| lookaheads on which this STATE raises a parse error (%nonassoc).   |
+`-------------------------------------------------------------------*/
 
 static void
-flush_shift (int state, int token)
+set_conflicts (state_t *state, symbol_t **errs)
 {
-  register shifts *shiftp;
-  register int k, i;
-/*  register unsigned symbol; JF unused */
+  int i;
+  transitions_t *transitions = state->transitions;
+  reductions_t *reds = state->reductions;
+
+  if (state->consistent)
+    return;
 
-  shiftp = shift_table[state];
+  bitset_zero (lookaheadset);
 
-  if (shiftp)
+  FOR_EACH_SHIFT (transitions, i)
+    bitset_set (lookaheadset, TRANSITION_SYMBOL (transitions, 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 = 0; i < reds->num; ++i)
+    if (reds->rules[i]->prec && reds->rules[i]->prec->prec
+	&& !bitset_disjoint_p (reds->lookaheads[i], lookaheadset))
+      {
+	resolve_sr_conflict (state, i, errs);
+	break;
+      }
+
+  /* Loop over all rules which require lookahead in this state.  Check
+     for conflicts not resolved above.  */
+  for (i = 0; i < reds->num; ++i)
     {
-      k = shiftp->nshifts;
-      for (i = 0; i < k; i++)
-	{
-	  if (shiftp->shifts[i] && token == accessing_symbol[shiftp->shifts[i]])
-	    (shiftp->shifts[i]) = 0;
-	}
+      if (!bitset_disjoint_p (reds->lookaheads[i], lookaheadset))
+	conflicts[state->number] = 1;
+
+      bitset_or (lookaheadset, lookaheadset, reds->lookaheads[i]);
     }
 }
 
 
-static void
-log_resolution (int state, int LAno, int token, char *resolution)
-{
-  fprintf(foutput,
-	  _("Conflict in state %d between rule %d and token %s resolved as %s.\n"),
-	  state, LAruleno[LAno], tags[token], resolution);
-}
-
+/*----------------------------------------------------------------.
+| Solve all the S/R conflicts using the precedence/associativity, |
+| and flag as inconsistent the states that still have conflicts.  |
+`----------------------------------------------------------------*/
 
 void
-conflict_log (void)
+conflicts_solve (void)
 {
-  register int i;
+  state_number_t i;
+  /* List of lookaheads on which we explicitly raise a parse error.  */
+  symbol_t **errs = XMALLOC (symbol_t *, ntokens + 1);
 
-  src_total = 0;
-  rrc_total = 0;
+  conflicts = XCALLOC (char, nstates);
+  shiftset = bitset_create (ntokens, BITSET_FIXED);
+  lookaheadset = bitset_create (ntokens, BITSET_FIXED);
+  obstack_init (&solved_conflicts_obstack);
 
   for (i = 0; i < nstates; i++)
     {
-      if (conflicts[i])
-	{
-	  count_sr_conflicts(i);
-	  count_rr_conflicts(i);
-	  src_total += src_count;
-	  rrc_total += rrc_count;
-	}
+      set_conflicts (states[i], errs);
+
+      /* For uniformity of the code, make sure all the states have a valid
+	 `errs' member.  */
+      if (!states[i]->errs)
+	states[i]->errs = errs_new (0, 0);
     }
 
-  total_conflicts();
+  free (errs);
 }
 
 
-void
-verbose_conflict_log (void)
+/*---------------------------------------------.
+| Count the number of shift/reduce conflicts.  |
+`---------------------------------------------*/
+
+static int
+count_sr_conflicts (state_t *state)
 {
-  register int i;
+  int i;
+  int src_count = 0;
+  transitions_t *transitions = state->transitions;
+  reductions_t *reds = state->reductions;
 
-  src_total = 0;
-  rrc_total = 0;
+  if (!transitions)
+    return 0;
 
-  for (i = 0; i < nstates; i++)
-    {
-      if (conflicts[i])
-	{
-	  count_sr_conflicts(i);
-	  count_rr_conflicts(i);
-	  src_total += src_count;
-	  rrc_total += rrc_count;
+  bitset_zero (lookaheadset);
+  bitset_zero (shiftset);
 
-	  fprintf(foutput, _("State %d contains"), i);
+  FOR_EACH_SHIFT (transitions, i)
+    bitset_set (shiftset, TRANSITION_SYMBOL (transitions, i));
 
-	  if (src_count == 1)
-	    fprintf(foutput, _(" 1 shift/reduce conflict"));
-	  else if (src_count > 1)
-	    fprintf(foutput, _(" %d shift/reduce conflicts"), src_count);
+  for (i = 0; i < reds->num; ++i)
+    bitset_or (lookaheadset, lookaheadset, reds->lookaheads[i]);
 
-	  if (src_count > 0 && rrc_count > 0)
-	    fprintf(foutput, _(" and"));
+  bitset_and (lookaheadset, lookaheadset, shiftset);
 
-	  if (rrc_count == 1)
-	    fprintf(foutput, _(" 1 reduce/reduce conflict"));
-	  else if (rrc_count > 1)
-	    fprintf(foutput, _(" %d reduce/reduce conflicts"), rrc_count);
+  src_count = bitset_count (lookaheadset);
 
-	  putc('.', foutput);
-	  putc('\n', foutput);
-	}
-    }
-
-  total_conflicts();
+  return src_count;
 }
 
 
-static void
-total_conflicts (void)
+/*----------------------------------------------------------------.
+| Count the number of reduce/reduce conflicts.  If ONE_PER_TOKEN, |
+| count one conflict for each token that has any reduce/reduce    |
+| conflicts.  Otherwise, count one conflict for each pair of      |
+| conflicting reductions.                                         |
++`----------------------------------------------------------------*/
+
+static int
+count_rr_conflicts (state_t *state, int one_per_token)
 {
-  if (src_total == expected_conflicts && rrc_total == 0)
-    return;
+  int i;
+  reductions_t *reds = state->reductions;
+  int rrc_count = 0;
 
-  if (fixed_outfiles)
+  for (i = 0; i < ntokens; i++)
     {
-      /* If invoked under the name `yacc', use the output format
-	 specified by POSIX.  */
-      fprintf(stderr, _("conflicts: "));
-      if (src_total > 0)
-	fprintf(stderr, _(" %d shift/reduce"), src_total);
-      if (src_total > 0 && rrc_total > 0)
-	fprintf(stderr, ",");
-      if (rrc_total > 0)
-	fprintf(stderr, _(" %d reduce/reduce"), rrc_total);
-      putc('\n', stderr);
+      int count = 0;
+      int j;
+      for (j = 0; j < reds->num; ++j)
+	if (bitset_test (reds->lookaheads[j], i))
+	  count++;
+
+      if (count >= 2)
+	rrc_count += one_per_token ? 1 : count-1;
     }
-  else
-    {
-      fprintf(stderr, _("%s contains"), infile);
-
-      if (src_total == 1)
-	fprintf(stderr, _(" 1 shift/reduce conflict"));
-      else if (src_total > 1)
-	fprintf(stderr, _(" %d shift/reduce conflicts"), src_total);
-
-      if (src_total > 0 && rrc_total > 0)
-	fprintf(stderr, _(" and"));
-
-      if (rrc_total == 1)
-	fprintf(stderr, _(" 1 reduce/reduce conflict"));
-      else if (rrc_total > 1)
-	fprintf(stderr, _(" %d reduce/reduce conflicts"), rrc_total);
 
-      putc('.', stderr);
-      putc('\n', stderr);
-    }
+  return rrc_count;
 }
 
 
-static void
-count_sr_conflicts (int state)
-{
-  register int i;
-  register int k;
-  register int mask;
-  register shifts *shiftp;
-  register unsigned *fp1;
-  register unsigned *fp2;
-  register unsigned *fp3;
-  register int symbol;
+/*--------------------------------------------------------------.
+| Return a human readable string which reports shift/reduce and |
+| reduce/reduce conflict numbers (SRC_NUM, RRC_NUM).            |
+`--------------------------------------------------------------*/
 
-  src_count = 0;
-
-  shiftp = shift_table[state];
-  if (!shiftp) return;
+static const char *
+conflict_report (int src_num, int rrc_num)
+{
+  static char res[4096];
+  char *cp = res;
 
-  for (i = 0; i < tokensetsize; i++)
+  if (src_num >= 1)
     {
-      shiftset[i] = 0;
-      lookaheadset[i] = 0;
+      sprintf (cp, ngettext ("%d shift/reduce conflict",
+			     "%d shift/reduce conflicts", src_num), src_num);
+      cp += strlen (cp);
     }
 
-  k = shiftp->nshifts;
-  for (i = 0; i < k; i++)
+  if (src_num > 0 && rrc_num > 0)
     {
-      if (! shiftp->shifts[i]) continue;
-      symbol = accessing_symbol[shiftp->shifts[i]];
-      if (ISVAR(symbol)) break;
-      SETBIT(shiftset, symbol);
+      sprintf (cp, " %s ", _("and"));
+      cp += strlen (cp);
     }
 
-  k = lookaheads[state + 1];
-  fp3 = lookaheadset + tokensetsize;
-
-  for (i = lookaheads[state]; i < k; i++)
+  if (rrc_num >= 1)
     {
-      fp1 = LA + i * tokensetsize;
-      fp2 = lookaheadset;
-
-      while (fp2 < fp3)
-	*fp2++ |= *fp1++;
+      sprintf (cp, ngettext ("%d reduce/reduce conflict",
+			     "%d reduce/reduce conflicts", rrc_num), rrc_num);
+      cp += strlen (cp);
     }
 
-  fp1 = shiftset;
-  fp2 = lookaheadset;
-
-  while (fp2 < fp3)
-    *fp2++ &= *fp1++;
+  *cp++ = '\0';
 
-  mask = 1;
-  fp2 = lookaheadset;
-  for (i = 0; i < ntokens; i++)
-    {
-      if (mask & *fp2)
-	src_count++;
-
-      mask <<= 1;
-      if (mask == 0)
-	{
-	  mask = 1;
-	  fp2++;
-	}
-    }
+  return res;
 }
 
 
+/*----------------------------------------------------------------.
+| Same as above, but report the number of conflicts a` la POSIX.  |
+`----------------------------------------------------------------*/
+
 static void
-count_rr_conflicts (int state)
+conflict_report_yacc (int src_num, int rrc_num)
 {
-  register int i;
-  register int j;
-  register int count;
-  register unsigned mask;
-  register unsigned *baseword;
-  register unsigned *wordp;
-  register int m;
-  register int n;
-
-  rrc_count = 0;
+  /* If invoked with `--yacc', use the output format specified by
+     POSIX.  */
+  fprintf (stderr, _("conflicts: "));
+  if (src_num > 0)
+    fprintf (stderr, _(" %d shift/reduce"), src_num);
+  if (src_num > 0 && rrc_num > 0)
+    fprintf (stderr, ",");
+  if (rrc_num > 0)
+    fprintf (stderr, _(" %d reduce/reduce"), rrc_num);
+  putc ('\n', stderr);
+}
 
-  m = lookaheads[state];
-  n = lookaheads[state + 1];
 
-  if (n - m < 2) return;
+/*-----------------------------------------------------------.
+| Output the detailed description of states with conflicts.  |
+`-----------------------------------------------------------*/
 
-  mask = 1;
-  baseword = LA + m * tokensetsize;
-  for (i = 0; i < ntokens; i++)
+void
+conflicts_output (FILE *out)
+{
+  bool printed_sth = FALSE;
+  state_number_t i;
+  for (i = 0; i < nstates; i++)
     {
-      wordp = baseword;
-
-      count = 0;
-      for (j = m; j < n; j++)
-	{
-	  if (mask & *wordp)
-	    count++;
-
-	  wordp += tokensetsize;
-	}
-
-      if (count >= 2) rrc_count++;
-
-      mask <<= 1;
-      if (mask == 0)
+      state_t *s = states[i];
+      if (conflicts[i])
 	{
-	  mask = 1;
-	  baseword++;
+	  fprintf (out, _("State %d contains "), i);
+	  fprintf (out, "%s.\n",
+		   conflict_report (count_sr_conflicts (s),
+				    count_rr_conflicts (s, TRUE)));
+	  printed_sth = TRUE;
 	}
     }
+  if (printed_sth)
+    fputs ("\n\n", out);
 }
 
+/*--------------------------------------------------------.
+| Total the number of S/R and R/R conflicts.  Unlike the  |
+| code in conflicts_output, however, count EACH pair of   |
+| reductions for the same state and lookahead as one      |
+| conflict.						  |
+`--------------------------------------------------------*/
 
-void
-print_reductions (int state)
+int
+conflicts_total_count (void)
 {
-  register int i;
-  register int j;
-  register int k;
-  register unsigned *fp1;
-  register unsigned *fp2;
-  register unsigned *fp3;
-  register unsigned *fp4;
-  register int rule;
-  register int symbol;
-  register unsigned mask;
-  register int m;
-  register int n;
-  register int default_LA;
-  register int default_rule = 0;
-  register int cmax;
-  register int count;
-  register shifts *shiftp;
-  register errs *errp;
-  int nodefault = 0;
-
-  for (i = 0; i < tokensetsize; i++)
-    shiftset[i] = 0;
-
-  shiftp = shift_table[state];
-  if (shiftp)
-    {
-      k = shiftp->nshifts;
-      for (i = 0; i < k; i++)
-	{
-	  if (! shiftp->shifts[i]) continue;
-	  symbol = accessing_symbol[shiftp->shifts[i]];
-	  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);
-	}
-    }
+  state_number_t i;
+  int count;
 
-  errp = err_table[state];
-  if (errp)
-    {
-      k = errp->nerrs;
-      for (i = 0; i < k; i++)
-	{
-	  if (! errp->errs[i]) continue;
-	  symbol = errp->errs[i];
-	  SETBIT(shiftset, symbol);
-	}
-    }
+  /* Conflicts by state.  */
+  count = 0;
+  for (i = 0; i < nstates; i++)
+    if (conflicts[i])
+      {
+	count += count_sr_conflicts (states[i]);
+	count += count_rr_conflicts (states[i], FALSE);
+      }
+  return count;
+}
 
-  m = lookaheads[state];
-  n = lookaheads[state + 1];
 
-  if (n - m == 1 && ! nodefault)
-    {
-      default_rule = LAruleno[m];
+/*------------------------------------------.
+| Reporting the total number of conflicts.  |
+`------------------------------------------*/
 
-      fp1 = LA + m * tokensetsize;
-      fp2 = shiftset;
-      fp3 = lookaheadset;
-      fp4 = lookaheadset + tokensetsize;
+void
+conflicts_print (void)
+{
+  /* 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
+     case we want equality.  */
+  int src_ok = 0;
 
-      while (fp3 < fp4)
-	*fp3++ = *fp1++ & *fp2++;
+  int src_total = 0;
+  int rrc_total = 0;
 
-      mask = 1;
-      fp3 = lookaheadset;
+  /* Conflicts by state.  */
+  {
+    state_number_t i;
 
-      for (i = 0; i < ntokens; i++)
+    for (i = 0; i < nstates; i++)
+      if (conflicts[i])
 	{
-	  if (mask & *fp3)
-	    fprintf(foutput, _("    %-4s\t[reduce using rule %d (%s)]\n"),
-		    tags[i], default_rule, tags[rlhs[default_rule]]);
-
-	  mask <<= 1;
-	  if (mask == 0)
-	    {
-	      mask = 1;
-	      fp3++;
-	    }
+	  src_total += count_sr_conflicts (states[i]);
+	  rrc_total += count_rr_conflicts (states[i], TRUE);
 	}
+  }
 
-      fprintf(foutput, _("    $default\treduce using rule %d (%s)\n\n"),
-	      default_rule, tags[rlhs[default_rule]]);
-    }
-  else if (n - m >= 1)
-    {
-      cmax = 0;
-      default_LA = -1;
-      fp4 = lookaheadset + tokensetsize;
+  src_ok = src_total == (expected_conflicts == -1 ? 0 : expected_conflicts);
 
-      if (! nodefault)
-	for (i = m; i < n; i++)
-	  {
-	    fp1 = LA + i * tokensetsize;
-	    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)
-        {
-          k = shiftp->nshifts;
-          for (i = 0; i < k; i++)
-	    {
-	      if (! shiftp->shifts[i]) continue;
-	      symbol = accessing_symbol[shiftp->shifts[i]];
-	      if (ISVAR(symbol)) break;
-	      SETBIT(shiftset, symbol);
-	    }
-        }
-
-      mask = 1;
-      fp1 = LA + m * tokensetsize;
-      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)
-			{
-			  rule = LAruleno[j];
-			  fprintf(foutput, _("    %-4s\treduce using rule %d (%s)\n"),
-				  tags[i], rule, tags[rlhs[rule]]);
-			}
-		      else defaulted = 1;
-
-		      count++;
-		    }
-		  else
-		    {
-		      if (defaulted)
-			{
-			  rule = LAruleno[default_LA];
-			  fprintf(foutput, _("    %-4s\treduce using rule %d (%s)\n"),
-				  tags[i], rule, tags[rlhs[rule]]);
-			  defaulted = 0;
-			}
-		      rule = LAruleno[j];
-		      fprintf(foutput, _("    %-4s\t[reduce using rule %d (%s)]\n"),
-			      tags[i], rule, tags[rlhs[rule]]);
-		    }
-		}
-
-	      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 there are no RR conflicts, and as many SR conflicts as
+     expected, then there is nothing to report.  */
+  if (!rrc_total && src_ok)
+    return;
 
-      if (default_LA >= 0)
-	{
-	  fprintf(foutput, _("    $default\treduce using rule %d (%s)\n"),
-		  default_rule, tags[rlhs[default_rule]]);
-	}
+  /* Report the total number of conflicts on STDERR.  */
+  if (yacc_flag)
+    conflict_report_yacc (src_total, rrc_total);
+  else
+    warn ("%s", conflict_report (src_total, rrc_total));
 
-      putc('\n', foutput);
-    }
+  if (expected_conflicts != -1 && !src_ok)
+    complain (ngettext ("expected %d shift/reduce conflict",
+			"expected %d shift/reduce conflicts",
+			expected_conflicts),
+	      expected_conflicts);
 }
 
 
 void
-finalize_conflicts (void)
+conflicts_free (void)
 {
-  FREE(conflicts);
-  FREE(shiftset);
-  FREE(lookaheadset);
+  XFREE (conflicts);
+  bitset_free (shiftset);
+  bitset_free (lookaheadset);
+  obstack_free (&solved_conflicts_obstack, NULL);
 }