]> git.saurik.com Git - bison.git/blobdiff - src/conflicts.c
* src/LR0.c (state_list_t, state_list_append): New.
[bison.git] / src / conflicts.c
index 0ba2e5ac4315ec8953341395a4d188842810cd5d..028768174ed80765ea3be9637a7a98839d10abe9 100644 (file)
@@ -48,12 +48,17 @@ enum conflict_resolution_e
     reduce_resolution,
     left_resolution,
     right_resolution,
-    nonassoc_resolution,
+    nonassoc_resolution
   };
 
 
+/*----------------------------------------------------------------.
+| Explain how an SR conflict between TOKEN and RULE was resolved: |
+| RESOLUTION.                                                     |
+`----------------------------------------------------------------*/
+
 static inline void
-log_resolution (int lookahead, int token,
+log_resolution (rule_t *rule, int token,
                enum conflict_resolution_e resolution)
 {
   if (report_flag & report_solved_conflicts)
@@ -66,7 +71,7 @@ log_resolution (int lookahead, int token,
          obstack_fgrow2 (&solved_conflicts_obstack,
                          _("\
     Conflict between rule %d and token %s resolved as shift"),
-                         LArule[lookahead]->number,
+                         rule->number,
                          symbols[token]->tag);
          break;
        case reduce_resolution:
@@ -74,14 +79,14 @@ log_resolution (int lookahead, int token,
          obstack_fgrow2 (&solved_conflicts_obstack,
                          _("\
     Conflict between rule %d and token %s resolved as reduce"),
-                         LArule[lookahead]->number,
+                         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"),
-                         LArule[lookahead]->number,
+                         rule->number,
                          symbols[token]->tag);
          break;
        }
@@ -92,7 +97,7 @@ log_resolution (int lookahead, int token,
        case shift_resolution:
          obstack_fgrow2 (&solved_conflicts_obstack,
                          " (%s < %s)",
-                         LArule[lookahead]->prec->tag,
+                         rule->prec->tag,
                          symbols[token]->tag);
          break;
 
@@ -100,11 +105,11 @@ log_resolution (int lookahead, int token,
          obstack_fgrow2 (&solved_conflicts_obstack,
                          " (%s < %s)",
                          symbols[token]->tag,
-                         LArule[lookahead]->prec->tag);
+                         rule->prec->tag);
          break;
 
        case left_resolution:
-         obstack_printf (&solved_conflicts_obstack,
+         obstack_fgrow1 (&solved_conflicts_obstack,
                          " (%%left %s)",
                          symbols[token]->tag);
          break;
@@ -134,7 +139,7 @@ log_resolution (int lookahead, int token,
 static void
 flush_shift (state_t *state, int token)
 {
-  shifts *shiftp = state->shifts;
+  shifts_t *shiftp = state->shifts;
   int i;
 
   bitset_reset (lookaheadset, token);
@@ -151,9 +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);
 }
 
 
@@ -162,19 +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 = LArule[lookahead]->prec->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)
       {
@@ -183,13 +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 (lookahead, i, reduce_resolution);
+           log_resolution (redrule, i, reduce_resolution);
            flush_shift (state, i);
          }
        else if (symbols[i]->prec > redprec)
          {
-           log_resolution (lookahead, i, shift_resolution);
-           flush_reduce (lookahead, i);
+           log_resolution (redrule, i, shift_resolution);
+           flush_reduce (lookaheads, i);
          }
        else
          /* Matching precedence levels.
@@ -200,22 +209,26 @@ resolve_sr_conflict (state_t *state, int lookahead)
          switch (symbols[i]->assoc)
            {
            case right_assoc:
-             log_resolution (lookahead, i, right_resolution);
-             flush_reduce (lookahead, i);
+             log_resolution (redrule, i, right_resolution);
+             flush_reduce (lookaheads, i);
              break;
 
            case left_assoc:
-             log_resolution (lookahead, i, left_resolution);
+             log_resolution (redrule, i, left_resolution);
              flush_shift (state, i);
              break;
 
            case non_assoc:
-             log_resolution (lookahead, i, nonassoc_resolution);
+             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;
            }
       }
 
@@ -236,7 +249,7 @@ static void
 set_conflicts (state_t *state)
 {
   int i;
-  shifts *shiftp;
+  shifts_t *shiftp;
 
   if (state->consistent)
     return;
@@ -250,13 +263,13 @@ 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 (LArule[state->lookaheadsp + i]->prec
-       && LArule[state->lookaheadsp + i]->prec->prec
-       && !bitset_disjoint_p (LA[state->lookaheadsp + i], lookaheadset))
+    if (state->lookaheads_rule[i]->prec
+       && state->lookaheads_rule[i]->prec->prec
+       && !bitset_disjoint_p (state->lookaheads[i], lookaheadset))
       {
-       resolve_sr_conflict (state, state->lookaheadsp + i);
+       resolve_sr_conflict (state, i);
        break;
       }
 
@@ -264,17 +277,17 @@ set_conflicts (state_t *state)
      for conflicts not resolved above.  */
   for (i = 0; i < state->nlookaheads; ++i)
     {
-      if (!bitset_disjoint_p (LA[state->lookaheadsp + i], lookaheadset))
+      if (!bitset_disjoint_p (state->lookaheads[i], lookaheadset))
        conflicts[state->number] = 1;
 
-      bitset_or (lookaheadset, lookaheadset, LA[state->lookaheadsp + i]);
+      bitset_or (lookaheadset, lookaheadset, state->lookaheads[i]);
     }
 }
 
 void
 conflicts_solve (void)
 {
-  size_t i;
+  state_number_t i;
 
   conflicts = XCALLOC (char, nstates);
   shiftset = bitset_create (ntokens, BITSET_FIXED);
@@ -295,7 +308,7 @@ count_sr_conflicts (state_t *state)
 {
   int i;
   int src_count = 0;
-  shifts *shiftp = state->shifts;
+  shifts_t *shiftp = state->shifts;
 
   if (!shiftp)
     return 0;
@@ -308,7 +321,7 @@ count_sr_conflicts (state_t *state)
       bitset_set (shiftset, SHIFT_SYMBOL (shiftp, i));
 
   for (i = 0; i < state->nlookaheads; ++i)
-    bitset_or (lookaheadset, lookaheadset, LA[state->lookaheadsp + i]);
+    bitset_or (lookaheadset, lookaheadset, state->lookaheads[i]);
 
   bitset_and (lookaheadset, lookaheadset, shiftset);
 
@@ -318,12 +331,15 @@ count_sr_conflicts (state_t *state)
 }
 
 
-/*----------------------------------------------.
-| Count the number of reduce/reduce conflicts.  |
-`----------------------------------------------*/
+/*----------------------------------------------------------------.
+| 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)
+count_rr_conflicts (state_t *state, int one_per_token)
 {
   int i;
   int rrc_count = 0;
@@ -336,11 +352,11 @@ 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)
-       rrc_count++;
+       rrc_count += one_per_token ? 1 : count-1;
     }
 
   return rrc_count;
@@ -393,19 +409,43 @@ void
 conflicts_output (FILE *out)
 {
   bool printed_sth = FALSE;
-  size_t i;
+  state_number_t i;
   for (i = 0; i < nstates; i++)
     if (conflicts[i])
       {
        fprintf (out, _("State %d contains "), i);
        fputs (conflict_report (count_sr_conflicts (states[i]),
-                               count_rr_conflicts (states[i])), out);
+                               count_rr_conflicts (states[i], TRUE)), out);
        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.                                              |
+`--------------------------------------------------------*/
+
+int
+conflicts_total_count (void)
+{
+  state_number_t i;
+  int count;
+
+  /* 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;
+}
+
 
 /*------------------------------------------.
 | Reporting the total number of conflicts.  |
@@ -414,8 +454,6 @@ conflicts_output (FILE *out)
 void
 conflicts_print (void)
 {
-  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
      case we want equality.  */
@@ -425,12 +463,16 @@ conflicts_print (void)
   int rrc_total = 0;
 
   /* Conflicts by state.  */
-  for (i = 0; i < nstates; i++)
-    if (conflicts[i])
-      {
-       src_total += count_sr_conflicts (states[i]);
-       rrc_total += count_rr_conflicts (states[i]);
-      }
+  {
+    state_number_t i;
+
+    for (i = 0; i < nstates; i++)
+      if (conflicts[i])
+       {
+         src_total += count_sr_conflicts (states[i]);
+         rrc_total += count_rr_conflicts (states[i], TRUE);
+       }
+  }
 
   src_ok = src_total == (expected_conflicts == -1 ? 0 : expected_conflicts);