parser: use %empty

[bison.git] / src / symtab.c

diff --git a/src/symtab.c b/src/symtab.c
index cc81c5f94a7747888241c156fd324f00d7784c8a..b132e07bcd2b71ccfc61a3443760cc00587dc3b1 100644 (file)
--- a/src/symtab.c
+++ b/src/symtab.c
@@ -1,6 +1,6 @@
 /* Symbol table manager for Bison.
 
-   Copyright (C) 1984, 1989, 2000-2002, 2004-2012 Free Software
+   Copyright (C) 1984, 1989, 2000-2002, 2004-2013 Free Software
    Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
@@ -46,6 +46,17 @@ symbol *accept = NULL;
 symbol *startsymbol = NULL;
 location startsymbol_location;
 
+/*---------------------------.
+| Precedence relation graph. |
+`---------------------------*/
+
+static symgraph **prec_nodes;
+
+/*-----------------------------------.
+| Store which associativity is used. |
+`-----------------------------------*/
+
+bool *used_assoc = NULL;
 
 /*---------------------------------.
 | Create a new symbol, named TAG.  |
@@ -142,13 +153,13 @@ symbol_print (symbol const *s, FILE *f)
 {
   if (s)
     {
-      fprintf (f, "\"%s\"", s->tag);
+      fputs (s->tag, f);
       SYMBOL_ATTR_PRINT (type_name);
       SYMBOL_CODE_PRINT (destructor);
       SYMBOL_CODE_PRINT (printer);
     }
   else
-    fprintf (f, "<NULL>");
+    fputs ("<NULL>", f);
 }
 
 #undef SYMBOL_ATTR_PRINT
@@ -971,3 +982,187 @@ symbols_pack (void)
               _("the start symbol %s is a token"),
               startsymbol->tag);
 }
+
+/*---------------------------------.
+| Initialize relation graph nodes. |
+`---------------------------------*/
+
+static void
+init_prec_nodes (void)
+{
+  int i;
+  prec_nodes = xcalloc (nsyms, sizeof *prec_nodes);
+  for (i = 0; i < nsyms; ++i)
+    {
+      prec_nodes[i] = xmalloc (sizeof *prec_nodes[i]);
+      symgraph *s = prec_nodes[i];
+      s->id = i;
+      s->succ = 0;
+      s->pred = 0;
+    }
+}
+
+/*----------------.
+| Create a link.  |
+`----------------*/
+
+static symgraphlink *
+symgraphlink_new (graphid id, symgraphlink *next)
+{
+  symgraphlink *l = xmalloc (sizeof *l);
+  l->id = id;
+  l->next = next;
+  return l;
+}
+
+
+/*------------------------------------------------------------------.
+| Register the second symbol of the precedence relation, and return |
+| whether this relation is new.  Use only in register_precedence.   |
+`------------------------------------------------------------------*/
+
+static bool
+register_precedence_second_symbol (symgraphlink **first, graphid sym)
+{
+  if (!*first || sym < (*first)->id)
+    *first = symgraphlink_new (sym, *first);
+  else
+    {
+      symgraphlink *slist = *first;
+
+      while (slist->next && slist->next->id <= sym)
+        slist = slist->next;
+
+      if (slist->id == sym)
+        /* Relation already present. */
+        return false;
+
+      slist->next = symgraphlink_new (sym, slist->next);
+    }
+  return true;
+}
+
+/*------------------------------------------------------------------.
+| Register a new relation between symbols as used. The first symbol |
+| has a greater precedence than the second one.                     |
+`------------------------------------------------------------------*/
+
+void
+register_precedence (graphid first, graphid snd)
+{
+  if (!prec_nodes)
+    init_prec_nodes ();
+  register_precedence_second_symbol (&(prec_nodes[first]->succ), snd);
+  register_precedence_second_symbol (&(prec_nodes[snd]->pred), first);
+}
+
+
+/*---------------------------------------.
+| Deep clear a linked / adjacency list). |
+`---------------------------------------*/
+
+static void
+linkedlist_free (symgraphlink *node)
+{
+  if (node)
+    {
+      while (node->next)
+        {
+          symgraphlink *tmp = node->next;
+          free (node);
+          node = tmp;
+        }
+      free (node);
+    }
+}
+
+/*----------------------------------------------.
+| Clear and destroy association tracking table. |
+`----------------------------------------------*/
+
+static void
+assoc_free (void)
+{
+  int i;
+  for (i = 0; i < nsyms; ++i)
+    {
+      linkedlist_free (prec_nodes[i]->pred);
+      linkedlist_free (prec_nodes[i]->succ);
+      free (prec_nodes[i]);
+    }
+  free (prec_nodes);
+}
+
+/*---------------------------------------.
+| Initialize association tracking table. |
+`---------------------------------------*/
+
+static void
+init_assoc (void)
+{
+  graphid i;
+  used_assoc = xcalloc(nsyms, sizeof(*used_assoc));
+  for (i = 0; i < nsyms; ++i)
+    used_assoc[i] = false;
+}
+
+/*------------------------------------------------------------------.
+| Test if the associativity for the symbols is defined and useless. |
+`------------------------------------------------------------------*/
+
+static inline bool
+is_assoc_useless (symbol *s)
+{
+  return s
+      && s->assoc != undef_assoc
+      && s->assoc != precedence_assoc
+      && !used_assoc[s->number];
+}
+
+/*-------------------------------.
+| Register a used associativity. |
+`-------------------------------*/
+
+void
+register_assoc (graphid i, graphid j)
+{
+  if (!used_assoc)
+    init_assoc ();
+  used_assoc[i] = true;
+  used_assoc[j] = true;
+}
+
+/*--------------------------------------------------.
+| Print a warning for unused precedence relations.  |
+`--------------------------------------------------*/
+
+void
+print_precedence_warnings (void)
+{
+  int i;
+  if (!prec_nodes)
+    init_prec_nodes ();
+  if (!used_assoc)
+    init_assoc ();
+  for (i = 0; i < nsyms; ++i)
+    {
+      symbol *s = symbols[i];
+      if (s
+          && s->prec != 0
+          && !prec_nodes[i]->pred
+          && !prec_nodes[i]->succ)
+        {
+          if (is_assoc_useless (s))
+            complain (&s->location, Wprecedence,
+                      _("useless precedence and associativity for %s"), s->tag);
+          else if (s->assoc == precedence_assoc)
+            complain (&s->location, Wprecedence,
+                      _("useless precedence for %s"), s->tag);
+        }
+      else if (is_assoc_useless (s))
+        complain (&s->location, Wprecedence,
+                  _("useless associativity for %s, use %%precedence"), s->tag);
+    }
+  free (used_assoc);
+  assoc_free ();
+}