X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/b86796bf874bdc68d99c18d3ec9f9460755b1963..8c165d891d5db7953b90142ed34cbbbc114e7f67:/src/conflicts.c

diff --git a/src/conflicts.c b/src/conflicts.c
index 6d9562bc..e09b6d87 100644
--- a/src/conflicts.c
+++ b/src/conflicts.c
@@ -1,5 +1,6 @@
 /* Find and resolve or report look-ahead conflicts for bison,
-   Copyright 1984, 1989, 1992, 2000, 2001, 2002 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.
 
@@ -34,20 +35,98 @@
 /* -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 (state_t *state, int LAno, int token, char *resolution)
+log_resolution (rule_t *rule, int token,
+		enum conflict_resolution_e resolution)
 {
-  if (verbose_flag)
-    obstack_fgrow4 (&output_obstack,
-		    _("\
-Conflict in state %d between rule %d and token %s resolved as %s.\n"),
-		    state->number, LAruleno[LAno], symbols[token]->tag,
-		    resolution);
+  if (report_flag & report_solved_conflicts)
+    {
+      /* The description of the resolution. */
+      switch (resolution)
+	{
+	case shift_resolution:
+	case left_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 right_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;
+	}
+
+      /* 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");
+    }
 }
 
 
@@ -77,9 +156,9 @@ flush_shift (state_t *state, int token)
 `-------------------------------------------------------------------*/
 
 static void
-flush_reduce (int lookahead, int token)
+flush_reduce (bitset lookaheads, int token)
 {
-  bitset_reset (LA[lookahead], token);
+  bitset_reset (lookaheads, token);
 }
 
 
@@ -88,19 +167,23 @@ flush_reduce (int lookahead, int token)
 | 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.      |
 `------------------------------------------------------------------*/
 
 static void
 resolve_sr_conflict (state_t *state, int lookahead)
 {
   int i;
-  /* find the rule to reduce by to get precedence of reduction  */
-  int redprec = rules[LAruleno[lookahead]].prec;
+  /* Find the rule to reduce by to get precedence of reduction.  */
+  rule_t *redrule = state->lookaheads_rule[lookahead];
+  int redprec = redrule->prec->prec;
+  bitset lookaheads = state->lookaheads[lookahead];
   errs *errp = errs_new (ntokens + 1);
   errp->nerrs = 0;
 
   for (i = 0; i < ntokens; i++)
-    if (bitset_test (LA[lookahead], i)
+    if (bitset_test (lookaheads, i)
 	&& bitset_test (lookaheadset, i)
 	&& symbols[i]->prec)
       {
@@ -109,13 +192,13 @@ resolve_sr_conflict (state_t *state, int lookahead)
 	   The precedence of shifting is that of token i.  */
 	if (symbols[i]->prec < redprec)
 	  {
-	    log_resolution (state, lookahead, i, _("reduce"));
+	    log_resolution (redrule, i, reduce_resolution);
 	    flush_shift (state, i);
 	  }
 	else if (symbols[i]->prec > redprec)
 	  {
-	    log_resolution (state, lookahead, i, _("shift"));
-	    flush_reduce (lookahead, i);
+	    log_resolution (redrule, i, shift_resolution);
+	    flush_reduce (lookaheads, i);
 	  }
 	else
 	  /* Matching precedence levels.
@@ -126,22 +209,26 @@ resolve_sr_conflict (state_t *state, int lookahead)
 	  switch (symbols[i]->assoc)
 	    {
 	    case right_assoc:
-	      log_resolution (state, lookahead, i, _("shift"));
-	      flush_reduce (lookahead, i);
+	      log_resolution (redrule, i, right_resolution);
+	      flush_reduce (lookaheads, i);
 	      break;
 
 	    case left_assoc:
-	      log_resolution (state, lookahead, i, _("reduce"));
+	      log_resolution (redrule, i, left_resolution);
 	      flush_shift (state, i);
 	      break;
 
 	    case non_assoc:
-	      log_resolution (state, lookahead, i, _("an error"));
+	      log_resolution (redrule, i, nonassoc_resolution);
 	      flush_shift (state, i);
-	      flush_reduce (lookahead, i);
+	      flush_reduce (lookaheads, i);
 	      /* Record an explicit error for this token.  */
 	      errp->errs[errp->nerrs++] = i;
 	      break;
+
+	    case undef_assoc:
+	      assert (symbols[i]->assoc != undef_assoc);
+	      break;
 	    }
       }
 
@@ -149,13 +236,19 @@ resolve_sr_conflict (state_t *state, int lookahead)
      permanent errs structure for this state, to record them.  */
   state->errs = errs_dup (errp);
   free (errp);
+
+  if (obstack_object_size (&solved_conflicts_obstack))
+    {
+      obstack_1grow (&solved_conflicts_obstack, '\0');
+      state->solved_conflicts = obstack_finish (&solved_conflicts_obstack);
+    }
 }
 
 
 static void
 set_conflicts (state_t *state)
 {
-  int i, j;
+  int i;
   shifts *shiftp;
 
   if (state->consistent)
@@ -170,43 +263,36 @@ set_conflicts (state_t *state)
 
   /* Loop over all rules which require lookahead in this state.  First
      check for shift-reduce conflict, and try to resolve using
-     precedence */
+     precedence.  */
   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, state->lookaheadsp + i);
-	    break;
-	  }
-
+    if (state->lookaheads_rule[i]->prec
+	&& state->lookaheads_rule[i]->prec->prec
+	&& !bitset_disjoint_p (state->lookaheads[i], lookaheadset))
+      {
+	resolve_sr_conflict (state, i);
+	break;
+      }
 
   /* Loop over all rules which require lookahead in this state.  Check
      for conflicts not resolved above.  */
   for (i = 0; i < state->nlookaheads; ++i)
     {
-      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 < ntokens; ++j)
-	if (bitset_test (LA[state->lookaheadsp + i], j))
-	  bitset_set (lookaheadset, j);
+      if (!bitset_disjoint_p (state->lookaheads[i], lookaheadset))
+	conflicts[state->number] = 1;
+
+      bitset_or (lookaheadset, lookaheadset, state->lookaheads[i]);
     }
 }
 
 void
-solve_conflicts (void)
+conflicts_solve (void)
 {
   size_t i;
 
   conflicts = XCALLOC (char, nstates);
   shiftset = bitset_create (ntokens, BITSET_FIXED);
-  bitset_zero (shiftset);
   lookaheadset = bitset_create (ntokens, BITSET_FIXED);
-  bitset_zero (lookaheadset);
+  obstack_init (&solved_conflicts_obstack);
 
   for (i = 0; i < nstates; i++)
     set_conflicts (states[i]);
@@ -220,7 +306,7 @@ solve_conflicts (void)
 static int
 count_sr_conflicts (state_t *state)
 {
-  int i, k;
+  int i;
   int src_count = 0;
   shifts *shiftp = state->shifts;
 
@@ -235,15 +321,11 @@ count_sr_conflicts (state_t *state)
       bitset_set (shiftset, SHIFT_SYMBOL (shiftp, i));
 
   for (i = 0; i < state->nlookaheads; ++i)
-    for (k = 0; k < ntokens; ++k)
-      if (bitset_test (LA[state->lookaheadsp + i], k))
-	bitset_set (lookaheadset, k);
+    bitset_or (lookaheadset, lookaheadset, state->lookaheads[i]);
 
   bitset_and (lookaheadset, lookaheadset, shiftset);
 
-  for (i = 0; i < ntokens; i++)
-    if (bitset_test (lookaheadset, i))
-      src_count++;
+  src_count = bitset_count (lookaheadset);
 
   return src_count;
 }
@@ -267,7 +349,7 @@ count_rr_conflicts (state_t *state)
       int count = 0;
       int j;
       for (j = 0; j < state->nlookaheads; ++j)
-	if (bitset_test (LA[state->lookaheadsp + j], i))
+	if (bitset_test (state->lookaheads[j], i))
 	  count++;
 
       if (count >= 2)
@@ -402,9 +484,10 @@ conflicts_print (void)
 
 
 void
-free_conflicts (void)
+conflicts_free (void)
 {
   XFREE (conflicts);
   bitset_free (shiftset);
   bitset_free (lookaheadset);
+  obstack_free (&solved_conflicts_obstack, NULL);
 }