X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/7d6bad195977b0204fc8406cac57cf5a4f1c769b..0fcc2e9a740785bc2aade5199f979832ebd74fdf:/src/symtab.c

diff --git a/src/symtab.c b/src/symtab.c
index 9014acf2..1c2372c1 100644
--- a/src/symtab.c
+++ b/src/symtab.c
@@ -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
@@ -232,9 +243,12 @@ symbol_type_set (symbol *sym, uniqstr type_name, location loc)
     {
       if (sym->type_name)
         symbol_redeclaration (sym, "%type", sym->type_location, loc);
-      uniqstr_assert (type_name);
-      sym->type_name = type_name;
-      sym->type_location = loc;
+      else
+        {
+          uniqstr_assert (type_name);
+          sym->type_name = type_name;
+          sym->type_location = loc;
+        }
     }
 }
 
@@ -250,7 +264,8 @@ symbol_code_props_set (symbol *sym, code_props_type kind,
     symbol_redeclaration (sym, code_props_type_string (kind),
                           sym->props[kind].location,
                           code->location);
-  sym->props[kind] = *code;
+  else
+    sym->props[kind] = *code;
 }
 
 /*-----------------------------------------------------.
@@ -266,7 +281,8 @@ semantic_type_code_props_set (semantic_type *type,
     semantic_type_redeclaration (type, code_props_type_string (kind),
                                  type->props[kind].location,
                                  code->location);
-  type->props[kind] = *code;
+  else
+    type->props[kind] = *code;
 }
 
 /*---------------------------------------------------.
@@ -310,12 +326,15 @@ symbol_precedence_set (symbol *sym, int prec, assoc a, location loc)
 {
   if (a != undef_assoc)
     {
-      if (sym->prec != 0)
+      if (sym->prec)
         symbol_redeclaration (sym, assoc_to_string (a), sym->prec_location,
                               loc);
-      sym->prec = prec;
-      sym->assoc = a;
-      sym->prec_location = loc;
+      else
+        {
+          sym->prec = prec;
+          sym->assoc = a;
+          sym->prec_location = loc;
+        }
     }
 
   /* Only terminals have a precedence. */
@@ -349,7 +368,8 @@ symbol_class_set (symbol *sym, symbol_class class, location loc, bool declaring)
     {
       if (sym->status == declared && !warned)
         complain (&loc, Wother, _("symbol %s redeclared"), sym->tag);
-      sym->status = declared;
+      else
+        sym->status = declared;
     }
 }
 
@@ -430,7 +450,7 @@ semantic_type_check_defined (semantic_type *sem_type)
   /* <*> and <> do not have to be "declared".  */
   if (sem_type->status == declared
       || !*sem_type->tag
-      || STREQ(sem_type->tag, "*"))
+      || STREQ (sem_type->tag, "*"))
     {
       int i;
       for (i = 0; i < 2; ++i)
@@ -604,8 +624,8 @@ symbol_translation (symbol *this)
           (this->user_token_number,
            symbols[token_translations[this->user_token_number]],
            this);
-
-      token_translations[this->user_token_number] = this->number;
+      else
+        token_translations[this->user_token_number] = this->number;
     }
 
   return true;
@@ -971,3 +991,187 @@ 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->prec_location, Wprecedence,
+                      _("useless precedence and associativity for %s"), s->tag);
+          else if (s->assoc == precedence_assoc)
+            complain (&s->prec_location, Wprecedence,
+                      _("useless precedence for %s"), s->tag);
+        }
+      else if (is_assoc_useless (s))
+        complain (&s->prec_location, Wprecedence,
+                  _("useless associativity for %s, use %%precedence"), s->tag);
+    }
+  free (used_assoc);
+  assoc_free ();
+}