grammar: warn about unused precedence for symbols

[bison.git] / src / graphviz.c

diff --git a/src/graphviz.c b/src/graphviz.c
index b37a28e0cdfc317a5edd3d704f8af78b6a742459..5ee41e73f3523fea0a306dc5f8bece5782649a5c 100644 (file)
--- a/src/graphviz.c
+++ b/src/graphviz.c
@@ -1,6 +1,6 @@
 /* Output Graphviz specification of a state machine generated by Bison.
 
-   Copyright (C) 2006-2007, 2009-2012 Free Software Foundation, Inc.
+   Copyright (C) 2006-2007, 2009-2013 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
@@ -53,7 +53,10 @@ start_graph (FILE *fout)
            "digraph %s\n"
            "{\n",
            quote (grammar_file));
-  fprintf (fout, "node [shape=box]\n");
+  fprintf (fout,
+           "  node [fontname = courier, shape = box, colorscheme = paired6]\n"
+           "  edge [fontname = courier]\n"
+           "\n");
 }
 
 void
@@ -93,13 +96,58 @@ no_reduce_bitset_init (state const *s, bitset *no_reduce_set)
       bitset_set (*no_reduce_set, s->errs->symbols[n]->number);
 }
 
+static void
+conclude_red (struct obstack *out, int source, rule_number ruleno,
+              bool enabled, bool first, FILE *fout)
+{
+  /* If no lookahead tokens were valid transitions, this reduction is
+     actually hidden, so cancel everything. */
+  if (first)
+    (void) obstack_finish0 (out);
+  else
+    {
+      char const *ed = enabled ? "" : "d";
+      char const *color = enabled ? ruleno ? "3" : "1" : "5";
+
+      /* First, build the edge's head. The name of reduction nodes is "nRm",
+         with n the source state and m the rule number. This is because we
+         don't want all the reductions bearing a same rule number to point to
+         the same state, since that is not the desired format. */
+      fprintf (fout, "  %1$d -> \"%1$dR%2$d%3$s\" [",
+               source, ruleno, ed);
+
+      /* (The lookahead tokens have been added to the beginning of the
+         obstack, in the caller function.) */
+      if (! obstack_empty_p (out))
+        {
+          char *label = obstack_finish0 (out);
+          fprintf (fout, "label=\"[%s]\", ", label);
+          obstack_free (out, label);
+        }
+
+      /* Then, the edge's tail. */
+      fprintf (fout, "style=solid]\n");
+
+      /* Build the associated diamond representation of the target rule. */
+      fprintf (fout, " \"%dR%d%s\" [label=\"",
+               source, ruleno, ed);
+      if (ruleno)
+        fprintf (fout, "R%d", ruleno);
+      else
+        fprintf (fout, "Acc");
+
+      fprintf (fout, "\", fillcolor=%s, shape=diamond, style=filled]\n",
+               color);
+    }
+}
+
 static bool
 print_token (struct obstack *out, bool first, char const *tok)
 {
   char const *q = escape (tok);
 
   if (! first)
-    obstack_sgrow (out, ",");
+    obstack_sgrow (out, ", ");
   obstack_sgrow (out, q);
   return false;
 }
@@ -110,58 +158,57 @@ output_red (state const *s, reductions const *reds, FILE *fout)
   bitset no_reduce_set;
   int j;
   int source = s->number;
-  struct obstack oout;
+
+  /* Two obstacks are needed: one for the enabled reductions, and one
+     for the disabled reductions, because in the end we want two
+     separate edges, even though in most cases only one will actually
+     be printed. */
+  struct obstack dout;
+  struct obstack eout;
 
   no_reduce_bitset_init (s, &no_reduce_set);
-  obstack_init (&oout);
+  obstack_init (&dout);
+  obstack_init (&eout);
 
   for (j = 0; j < reds->num; ++j)
     {
-      bool disabled = false;
-      bool first = true;
-      int ruleno = reds->rules[j]->user_number;
+      bool defaulted = false;
+      bool firstd = true;
+      bool firste = true;
+      rule_number ruleno = reds->rules[j]->number;
       rule *default_reduction = NULL;
 
       if (yydefact[s->number] != 0)
         default_reduction = &rules[yydefact[s->number] - 1];
 
-      /* First, print the edges that represent each possible reduction for
-         the given state. */
-      obstack_printf (&oout, "  %1$d -> \"%1$dR%2$d\" [label=\"",
-                      source, ruleno);
+      /* Build the lookahead tokens lists, one for enabled transitions and one
+         for disabled transistions. */
       if (default_reduction && default_reduction == reds->rules[j])
-        first = print_token (&oout, true, "$default");
-      else
+        defaulted = true;
+      if (reds->lookahead_tokens)
         {
           int i;
           for (i = 0; i < ntokens; i++)
             if (bitset_test (reds->lookahead_tokens[j], i))
               {
-                first = print_token (&oout, first, symbols[i]->tag);
                 if (bitset_test (no_reduce_set, i))
-                  disabled = true;
+                  firstd = print_token (&dout, firstd, symbols[i]->tag);
+                else
+                  {
+                    if (! defaulted)
+                      firste = print_token (&eout, firste, symbols[i]->tag);
+                    bitset_set (no_reduce_set, i);
+                  }
               }
         }
-      obstack_sgrow (&oout, "\" style=solid]\n");
-
-      /* Then, print the reduction's representation. This most be done later
-         because the we need the previously determined boolean to know if this
-         reduction is disabled or not. */
-      obstack_printf (&oout, " \"%dR%d\" "
-                             "[style=filled shape=diamond fillcolor=%s "
-                             "label=\"R%d\"]\n",
-                      source, ruleno,
-                      disabled ? "firebrick1" : "yellowgreen",
-                      ruleno);
-
-      /* If no lookahead tokens were valid transitions, this reduction is
-         actually disabled, so don't print it. */
-      if (first)
-        (void) obstack_finish0 (&oout);
-      else
-        fprintf (fout, obstack_finish0 (&oout));
+
+      /* Do the actual output. */
+      conclude_red (&dout, source, ruleno, false, firstd, fout);
+      conclude_red (&eout, source, ruleno, true, firste && !defaulted, fout);
     }
-  obstack_free (&oout, 0);
+  obstack_free (&dout, 0);
+  obstack_free (&eout, 0);
+  bitset_free (no_reduce_set);
 }
 
 void