* src/state.h (state_t): `solved_conflicts' is a new member.

[bison.git] / src / conflicts.c

diff --git a/src/conflicts.c b/src/conflicts.c
index d90b380aa4ef87b5fb8b1cdc6f3d5157b81a4e4b..0ba2e5ac4315ec8953341395a4d188842810cd5d 100644 (file)
--- 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 +35,93 @@
 /* -1 stands for not specified. */
 int expected_conflicts = -1;
 static char *conflicts = NULL;
+struct obstack solved_conflicts_obstack;
 
 static bitset shiftset;
 static bitset lookaheadset;
+
 \f
 
+enum conflict_resolution_e
+  {
+    shift_resolution,
+    reduce_resolution,
+    left_resolution,
+    right_resolution,
+    nonassoc_resolution,
+  };
+
+
 static inline void
-log_resolution (state_t *state, int LAno, int token, char *resolution)
+log_resolution (int lookahead, 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"),
+                         LArule[lookahead]->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"),
+                         LArule[lookahead]->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,
+                         symbols[token]->tag);
+         break;
+       }
+
+      /* The reason. */
+      switch (resolution)
+       {
+       case shift_resolution:
+         obstack_fgrow2 (&solved_conflicts_obstack,
+                         " (%s < %s)",
+                         LArule[lookahead]->prec->tag,
+                         symbols[token]->tag);
+         break;
+
+       case reduce_resolution:
+         obstack_fgrow2 (&solved_conflicts_obstack,
+                         " (%s < %s)",
+                         symbols[token]->tag,
+                         LArule[lookahead]->prec->tag);
+         break;
+
+       case left_resolution:
+         obstack_printf (&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");
+    }
 }
 
 
@@ -95,7 +169,7 @@ 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;
+  int redprec = LArule[lookahead]->prec->prec;
   errs *errp = errs_new (ntokens + 1);
   errp->nerrs = 0;
 
@@ -109,12 +183,12 @@ 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 (lookahead, i, reduce_resolution);
            flush_shift (state, i);
          }
        else if (symbols[i]->prec > redprec)
          {
-           log_resolution (state, lookahead, i, _("shift"));
+           log_resolution (lookahead, i, shift_resolution);
            flush_reduce (lookahead, i);
          }
        else
@@ -126,17 +200,17 @@ resolve_sr_conflict (state_t *state, int lookahead)
          switch (symbols[i]->assoc)
            {
            case right_assoc:
-             log_resolution (state, lookahead, i, _("shift"));
+             log_resolution (lookahead, i, right_resolution);
              flush_reduce (lookahead, i);
              break;
 
            case left_assoc:
-             log_resolution (state, lookahead, i, _("reduce"));
+             log_resolution (lookahead, i, left_resolution);
              flush_shift (state, i);
              break;
 
            case non_assoc:
-             log_resolution (state, lookahead, i, _("an error"));
+             log_resolution (lookahead, i, nonassoc_resolution);
              flush_shift (state, i);
              flush_reduce (lookahead, i);
              /* Record an explicit error for this token.  */
@@ -149,6 +223,12 @@ 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);
+    }
 }
 
 
@@ -172,7 +252,8 @@ set_conflicts (state_t *state)
      check for shift-reduce conflict, and try to resolve using
      precedence */
   for (i = 0; i < state->nlookaheads; ++i)
-    if (rules[LAruleno[state->lookaheadsp + i]].prec
+    if (LArule[state->lookaheadsp + i]->prec
+       && LArule[state->lookaheadsp + i]->prec->prec
        && !bitset_disjoint_p (LA[state->lookaheadsp + i], lookaheadset))
       {
        resolve_sr_conflict (state, state->lookaheadsp + i);
@@ -191,13 +272,14 @@ set_conflicts (state_t *state)
 }
 
 void
-solve_conflicts (void)
+conflicts_solve (void)
 {
   size_t i;
 
   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++)
     set_conflicts (states[i]);
@@ -389,9 +471,10 @@ conflicts_print (void)
 
 
 void
-free_conflicts (void)
+conflicts_free (void)
 {
   XFREE (conflicts);
   bitset_free (shiftset);
   bitset_free (lookaheadset);
+  obstack_free (&solved_conflicts_obstack, NULL);
 }