X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/5458913abab5e33938892b0d279f02f3b09d94db..bcd80897f3b414973fc34dc2ec57ce4df2e69253:/src/graphviz.c

diff --git a/src/graphviz.c b/src/graphviz.c
index 0007f9e0..9da5f6e3 100644
--- a/src/graphviz.c
+++ b/src/graphviz.c
@@ -25,12 +25,14 @@
 #include <quotearg.h>
 
 #include "files.h"
+#include "gram.h"
 #include "graphviz.h"
+#include "tables.h"
 
 /* Return an unambiguous printable representation for NAME, suitable
    for C strings.  Use slot 2 since the user may use slots 0 and 1.  */
 
-static char const *
+static char *
 quote (char const *name)
 {
   return quotearg_n_style (2, c_quoting_style, name);
@@ -51,12 +53,16 @@ start_graph (FILE *fout)
            "digraph %s\n"
            "{\n",
            quote (grammar_file));
+  fprintf (fout,
+           "  node [fontname = courier, shape = box, colorscheme = paired6]\n"
+           "  edge [fontname = courier]\n"
+           "\n");
 }
 
 void
 output_node (int id, char const *label, FILE *fout)
 {
-  fprintf (fout, "  %d [label=%s]\n", id, quote (label));
+  fprintf (fout, "  %d [label=\"%s\"]\n", id, label);
 }
 
 void
@@ -69,6 +75,142 @@ output_edge (int source, int destination, char const *label,
   fputs ("]\n", fout);
 }
 
+char const *
+escape (char const *name)
+{
+  char *q = quote (name);
+  q[strlen (q) - 1] = '\0';
+  return q + 1;
+}
+
+static void
+no_reduce_bitset_init (state const *s, bitset *no_reduce_set)
+{
+  int n;
+  *no_reduce_set = bitset_create (ntokens, BITSET_FIXED);
+  bitset_zero (*no_reduce_set);
+  FOR_EACH_SHIFT (s->transitions, n)
+    bitset_set (*no_reduce_set, TRANSITION_SYMBOL (s->transitions, n));
+  for (n = 0; n < s->errs->num; ++n)
+    if (s->errs->symbols[n])
+      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, q);
+  return false;
+}
+
+void
+output_red (state const *s, reductions const *reds, FILE *fout)
+{
+  bitset no_reduce_set;
+  int j;
+  int source = s->number;
+
+  /* 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 (&dout);
+  obstack_init (&eout);
+
+  for (j = 0; j < reds->num; ++j)
+    {
+      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];
+
+      /* Build the lookahead tokens lists, one for enabled transitions and one
+         for disabled transistions. */
+      if (default_reduction && default_reduction == reds->rules[j])
+        defaulted = true;
+      if (reds->lookahead_tokens)
+        {
+          int i;
+          for (i = 0; i < ntokens; i++)
+            if (bitset_test (reds->lookahead_tokens[j], i))
+              {
+                if (bitset_test (no_reduce_set, i))
+                  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);
+                  }
+              }
+        }
+
+      /* Do the actual output. */
+      conclude_red (&dout, source, ruleno, false, firstd, fout);
+      conclude_red (&eout, source, ruleno, true, firste && !defaulted, fout);
+    }
+  obstack_free (&dout, 0);
+  obstack_free (&eout, 0);
+  bitset_free (no_reduce_set);
+}
+
 void
 finish_graph (FILE *fout)
 {