X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/db34f7988941444bdc5f2b6adcf7fb83648f9a18..a17187e56386747a9b4d9633c3d116c2087f2b8b:/src/reader.c

diff --git a/src/reader.c b/src/reader.c
index f607f9ee..2e0aa5ee 100644
--- a/src/reader.c
+++ b/src/reader.c
@@ -1,7 +1,7 @@
 /* Input parser for Bison
 
-   Copyright (C) 1984, 1986, 1989, 1992, 1998, 2000, 2001, 2002, 2003,
-   2005, 2006, 2007, 2009 Free Software Foundation, Inc.
+   Copyright (C) 1984, 1986, 1989, 1992, 1998, 2000-2003, 2005-2007,
+   2009-2012 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
@@ -21,7 +21,7 @@
 #include <config.h>
 #include "system.h"
 
-#include <quotearg.h>
+#include <quote.h>
 
 #include "complain.h"
 #include "conflicts.h"
@@ -35,6 +35,7 @@
 #include "scan-gram.h"
 #include "scan-code.h"
 
+static void prepare_percent_define_front_end_variables (void);
 static void check_and_convert_grammar (void);
 
 static symbol_list *grammar = NULL;
@@ -93,7 +94,7 @@ get_merge_function (uniqstr name)
       syms->next = xmalloc (sizeof syms->next[0]);
       syms->next->name = uniqstr_new (name);
       /* After all symbol type declarations have been parsed, packgram invokes
-	 record_merge_function_type to set the type.  */
+         record_merge_function_type to set the type.  */
       syms->next->type = NULL;
       syms->next->next = NULL;
       merge_functions = head.next;
@@ -128,17 +129,17 @@ record_merge_function_type (int merger, uniqstr type, location declaration_loc)
   if (merge_function->type != NULL && !UNIQSTR_EQ (merge_function->type, type))
     {
       complain_at (declaration_loc,
-		   _("result type clash on merge function `%s': <%s> != <%s>"),
-		   merge_function->name, type, merge_function->type);
+                   _("result type clash on merge function %s: <%s> != <%s>"),
+                   quote (merge_function->name), type, merge_function->type);
       complain_at (merge_function->type_declaration_location,
-		   _("previous declaration"));
+                   _("previous declaration"));
     }
   merge_function->type = uniqstr_new (type);
   merge_function->type_declaration_location = declaration_loc;
 }
 
 /*--------------------------------------.
-| Free all merge-function definitions.	|
+| Free all merge-function definitions.  |
 `--------------------------------------*/
 
 void
@@ -169,7 +170,7 @@ free_merger_functions (void)
 static symbol_list *grammar_end = NULL;
 
 /* Append SYM to the grammar.  */
-static void
+static symbol_list *
 grammar_symbol_append (symbol *sym, location loc)
 {
   symbol_list *p = symbol_list_sym_new (sym, loc);
@@ -185,8 +186,27 @@ grammar_symbol_append (symbol *sym, location loc)
      part of it.  */
   if (sym)
     ++nritems;
+
+  return p;
 }
 
+static void
+assign_named_ref (symbol_list *p, named_ref *name)
+{
+  symbol *sym = p->content.sym;
+
+  if (name->id == sym->tag)
+    {
+      warn_at (name->loc,
+               _("duplicated symbol name for %s ignored"),
+               quote (sym->tag));
+      named_ref_free (name);
+    }
+  else
+    p->named_ref = name;
+}
+
+
 /* The rule currently being defined, and the previous rule.
    CURRENT_RULE points to the first LHS of the current rule, while
    PREVIOUS_RULE_END points to the *end* of the previous rule (NULL).  */
@@ -199,12 +219,19 @@ static symbol_list *previous_rule_end = NULL;
 `----------------------------------------------*/
 
 void
-grammar_current_rule_begin (symbol *lhs, location loc)
+grammar_current_rule_begin (symbol *lhs, location loc,
+                            named_ref *lhs_name)
 {
+  symbol_list* p;
+
   /* Start a new rule and record its lhs.  */
   ++nrules;
   previous_rule_end = grammar_end;
-  grammar_symbol_append (lhs, loc);
+
+  p = grammar_symbol_append (lhs, loc);
+  if (lhs_name)
+    assign_named_ref (p, named_ref_copy (lhs_name));
+
   current_rule = grammar_end;
 
   /* Mark the rule's lhs as a nonterminal if not already so.  */
@@ -222,22 +249,25 @@ grammar_current_rule_begin (symbol *lhs, location loc)
 /*----------------------------------------------------------------------.
 | A symbol should be used if either:                                    |
 |   1. It has a destructor.                                             |
-|   2. --warnings=midrule-values and the symbol is a mid-rule symbol    |
-|      (i.e., the generated LHS replacing a mid-rule action) that was   |
-|      assigned to or used, as in "exp: { $$ = 1; } { $$ = $1; }".      |
+|   2. The symbol is a mid-rule symbol (i.e., the generated LHS         |
+|      replacing a mid-rule action) that was assigned to or used, as in |
+|      "exp: { $$ = 1; } { $$ = $1; }".                                 |
 `----------------------------------------------------------------------*/
 
 static bool
-symbol_should_be_used (symbol_list const *s)
+symbol_should_be_used (symbol_list const *s, bool *midrule_warning)
 {
   if (symbol_destructor_get (s->content.sym)->code)
     return true;
-  if (warnings_flag & warnings_midrule_values)
-    return ((s->midrule && s->midrule->action_props.is_value_used)
-	    || (s->midrule_parent_rule
-		&& symbol_list_n_get (s->midrule_parent_rule,
-				      s->midrule_parent_rhs_index)
-                     ->action_props.is_value_used));
+  if ((s->midrule && s->midrule->action_props.is_value_used)
+      || (s->midrule_parent_rule
+          && symbol_list_n_get (s->midrule_parent_rule,
+                                s->midrule_parent_rhs_index)
+               ->action_props.is_value_used))
+    {
+      *midrule_warning = true;
+      return true;
+    }
   return false;
 }
 
@@ -261,19 +291,19 @@ grammar_rule_check (const symbol_list *r)
       symbol *first_rhs = r->next->content.sym;
       /* If $$ is being set in default way, report if any type mismatch.  */
       if (first_rhs)
-	{
-	  char const *lhs_type = r->content.sym->type_name;
-	  const char *rhs_type =
-	    first_rhs->type_name ? first_rhs->type_name : "";
-	  if (!UNIQSTR_EQ (lhs_type, rhs_type))
-	    warn_at (r->location,
-		     _("type clash on default action: <%s> != <%s>"),
-		     lhs_type, rhs_type);
-	}
+        {
+          char const *lhs_type = r->content.sym->type_name;
+          const char *rhs_type =
+            first_rhs->type_name ? first_rhs->type_name : "";
+          if (!UNIQSTR_EQ (lhs_type, rhs_type))
+            warn_at (r->location,
+                     _("type clash on default action: <%s> != <%s>"),
+                     lhs_type, rhs_type);
+        }
       /* Warn if there is no default for $$ but we need one.  */
       else
-	warn_at (r->location,
-		 _("empty rule for typed nonterminal, and no action"));
+        warn_at (r->location,
+                 _("empty rule for typed nonterminal, and no action"));
     }
 
   /* Check that symbol values that should be used are in fact used.  */
@@ -281,17 +311,31 @@ grammar_rule_check (const symbol_list *r)
     symbol_list const *l = r;
     int n = 0;
     for (; l && l->content.sym; l = l->next, ++n)
-      if (! (l->action_props.is_value_used
-	     || !symbol_should_be_used (l)
-	     /* The default action, $$ = $1, `uses' both.  */
-	     || (!r->action_props.code && (n == 0 || n == 1))))
-	{
-	  if (n)
-	    warn_at (r->location, _("unused value: $%d"), n);
-	  else
-	    warn_at (r->location, _("unset value: $$"));
-	}
+      {
+        bool midrule_warning = false;
+        if (!l->action_props.is_value_used
+            && symbol_should_be_used (l, &midrule_warning)
+            /* The default action, $$ = $1, `uses' both.  */
+            && (r->action_props.code || (n != 0 && n != 1)))
+          {
+            void (*warn_at_ptr)(location, char const*, ...) =
+              midrule_warning ? midrule_value_at : warn_at;
+            if (n)
+              warn_at_ptr (r->location, _("unused value: $%d"), n);
+            else
+              warn_at_ptr (r->location, _("unset value: $$"));
+          }
+      }
   }
+
+  /* See comments in grammar_current_rule_prec_set for how POSIX
+     mandates this complaint.  It's only for identifiers, so skip
+     it for char literals and strings, which are always tokens.  */
+  if (r->ruleprec
+      && r->ruleprec->tag[0] != '\'' && r->ruleprec->tag[0] != '"'
+      && !r->ruleprec->declared && !r->ruleprec->prec)
+    warn_at (r->location, _("token for %%prec is not defined: %s"),
+             r->ruleprec->tag);
 }
 
 
@@ -328,6 +372,9 @@ grammar_midrule_action (void)
   symbol *dummy = dummy_symbol_get (dummy_location);
   symbol_list *midrule = symbol_list_sym_new (dummy, dummy_location);
 
+  /* Remember named_ref of previous action. */
+  named_ref *action_name = current_rule->action_props.named_ref;
+
   /* Make a new rule, whose body is empty, before the current one, so
      that the action just read can belong to it.  */
   ++nrules;
@@ -337,7 +384,8 @@ grammar_midrule_action (void)
   code_props_rule_action_init (&midrule->action_props,
                                current_rule->action_props.code,
                                current_rule->action_props.location,
-                               midrule);
+                               midrule, 0,
+                               current_rule->action_props.is_predicate);
   code_props_none_init (&current_rule->action_props);
 
   if (previous_rule_end)
@@ -353,7 +401,8 @@ grammar_midrule_action (void)
 
   /* Insert the dummy nonterminal replacing the midrule action into
      the current rule.  Bind it to its dedicated rule.  */
-  grammar_current_rule_symbol_append (dummy, dummy_location);
+  grammar_current_rule_symbol_append (dummy, dummy_location,
+                                      action_name);
   grammar_end->midrule = midrule;
   midrule->midrule_parent_rule = current_rule;
   midrule->midrule_parent_rhs_index = symbol_list_length (current_rule->next);
@@ -364,6 +413,16 @@ grammar_midrule_action (void)
 void
 grammar_current_rule_prec_set (symbol *precsym, location loc)
 {
+  /* POSIX says that any identifier is a nonterminal if it does not
+     appear on the LHS of a grammar rule and is not defined by %token
+     or by one of the directives that assigns precedence to a token.  We
+     ignore this here because the only kind of identifier that POSIX
+     allows to follow a %prec is a token and because assuming it's a
+     token now can produce more logical error messages.  Nevertheless,
+     grammar_rule_check does obey what we believe is the real intent of
+     POSIX here: that an error be reported for any identifier that
+     appears after %prec but that is not defined separately as a
+     token.  */
   symbol_class_set (precsym, token_sym, loc, false);
   if (current_rule->ruleprec)
     complain_at (loc, _("only one %s allowed per rule"), "%prec");
@@ -402,24 +461,29 @@ grammar_current_rule_merge_set (uniqstr name, location loc)
    action as a mid-rule action.  */
 
 void
-grammar_current_rule_symbol_append (symbol *sym, location loc)
+grammar_current_rule_symbol_append (symbol *sym, location loc,
+                                    named_ref *name)
 {
+  symbol_list *p;
   if (current_rule->action_props.code)
     grammar_midrule_action ();
-  grammar_symbol_append (sym, loc);
+  p = grammar_symbol_append (sym, loc);
+  if (name)
+    assign_named_ref(p, name);
 }
 
 /* Attach an ACTION to the current rule.  */
 
 void
-grammar_current_rule_action_append (const char *action, location loc)
+grammar_current_rule_action_append (const char *action, location loc,
+                                    named_ref *name, bool is_predicate)
 {
   if (current_rule->action_props.code)
     grammar_midrule_action ();
   /* After all symbol declarations have been parsed, packgram invokes
      code_props_translate_code.  */
   code_props_rule_action_init (&current_rule->action_props, action, loc,
-                               current_rule);
+                               current_rule, name, is_predicate);
 }
 
 
@@ -447,7 +511,7 @@ packgram (void)
       int rule_length = 0;
       symbol *ruleprec = p->ruleprec;
       record_merge_function_type (p->merger, p->content.sym->type_name,
-				  p->merger_declaration_location);
+                                  p->merger_declaration_location);
       rules[ruleno].user_number = ruleno;
       rules[ruleno].number = ruleno;
       rules[ruleno].lhs = p->content.sym;
@@ -460,49 +524,50 @@ packgram (void)
       rules[ruleno].useful = true;
       rules[ruleno].action = p->action_props.code;
       rules[ruleno].action_location = p->action_props.location;
+      rules[ruleno].is_predicate = p->action_props.is_predicate;
 
       /* If the midrule's $$ is set or its $n is used, remove the `$' from the
-	 symbol name so that it's a user-defined symbol so that the default
-	 %destructor and %printer apply.  */
+         symbol name so that it's a user-defined symbol so that the default
+         %destructor and %printer apply.  */
       if (p->midrule_parent_rule
           && (p->action_props.is_value_used
-	      || symbol_list_n_get (p->midrule_parent_rule,
-				    p->midrule_parent_rhs_index)
+              || symbol_list_n_get (p->midrule_parent_rule,
+                                    p->midrule_parent_rhs_index)
                    ->action_props.is_value_used))
-	p->content.sym->tag += 1;
+        p->content.sym->tag += 1;
 
       /* Don't check the generated rule 0.  It has no action, so some rhs
-	 symbols may appear unused, but the parsing algorithm ensures that
-	 %destructor's are invoked appropriately.  */
+         symbols may appear unused, but the parsing algorithm ensures that
+         %destructor's are invoked appropriately.  */
       if (p != grammar)
-	grammar_rule_check (p);
+        grammar_rule_check (p);
 
       for (p = p->next; p && p->content.sym; p = p->next)
-	{
-	  ++rule_length;
+        {
+          ++rule_length;
 
-	  /* Don't allow rule_length == INT_MAX, since that might
-	     cause confusion with strtol if INT_MAX == LONG_MAX.  */
-	  if (rule_length == INT_MAX)
-	      fatal_at (rules[ruleno].location, _("rule is too long"));
+          /* Don't allow rule_length == INT_MAX, since that might
+             cause confusion with strtol if INT_MAX == LONG_MAX.  */
+          if (rule_length == INT_MAX)
+              fatal_at (rules[ruleno].location, _("rule is too long"));
 
-	  /* item_number = symbol_number.
-	     But the former needs to contain more: negative rule numbers. */
-	  ritem[itemno++] =
+          /* item_number = symbol_number.
+             But the former needs to contain more: negative rule numbers. */
+          ritem[itemno++] =
             symbol_number_as_item_number (p->content.sym->number);
-	  /* A rule gets by default the precedence and associativity
-	     of its last token.  */
-	  if (p->content.sym->class == token_sym && default_prec)
-	    rules[ruleno].prec = p->content.sym;
-	}
+          /* A rule gets by default the precedence and associativity
+             of its last token.  */
+          if (p->content.sym->class == token_sym && default_prec)
+            rules[ruleno].prec = p->content.sym;
+        }
 
       /* If this rule has a %prec,
          the specified symbol's precedence replaces the default.  */
       if (ruleprec)
-	{
-	  rules[ruleno].precsym = ruleprec;
-	  rules[ruleno].prec = ruleprec;
-	}
+        {
+          rules[ruleno].precsym = ruleprec;
+          rules[ruleno].prec = ruleprec;
+        }
       /* An item ends by the rule number (negated).  */
       ritem[itemno++] = rule_number_as_item_number (ruleno);
       aver (itemno < ITEM_NUMBER_MAX);
@@ -510,7 +575,7 @@ packgram (void)
       aver (ruleno < RULE_NUMBER_MAX);
 
       if (p)
-	p = p->next;
+        p = p->next;
     }
 
   aver (itemno == nritems);
@@ -554,39 +619,47 @@ reader (void)
   gram_debug = trace_flag & trace_parse;
   gram_scanner_initialize ();
   gram_parse ();
+  prepare_percent_define_front_end_variables ();
+
+  if (! complaint_issued)
+    check_and_convert_grammar ();
 
-  /* IELR would be a better default, but LALR is historically the default.  */
+  xfclose (gram_in);
+}
+
+static void
+prepare_percent_define_front_end_variables (void)
+{
+  /* Set %define front-end variable defaults.  */
+  muscle_percent_define_default ("lr.keep-unreachable-states", "false");
   {
     char *lr_type;
-    muscle_percent_define_default ("lr.type", "LALR");
+    /* IELR would be a better default, but LALR is historically the
+       default.  */
+    muscle_percent_define_default ("lr.type", "lalr");
     lr_type = muscle_percent_define_get ("lr.type");
-    if (0 != strcmp (lr_type, "canonical LR"))
-      muscle_percent_define_default ("lr.default_rules", "all");
+    if (STRNEQ (lr_type, "canonical-lr"))
+      muscle_percent_define_default ("lr.default-reductions", "most");
     else
-      muscle_percent_define_default ("lr.default_rules", "accepting");
+      muscle_percent_define_default ("lr.default-reductions", "accepting");
     free (lr_type);
   }
 
-  /* Check front-end %define variable values.  */
+  /* Check %define front-end variables.  */
   {
     static char const * const values[] = {
-      "lr.type", "LALR", "IELR", "canonical LR", NULL,
-      "lr.default_rules", "all", "consistent", "accepting", NULL,
+      "lr.type", "lalr", "ielr", "canonical-lr", NULL,
+      "lr.default-reductions", "most", "consistent", "accepting", NULL,
       NULL
     };
     muscle_percent_define_check_values (values);
   }
-
-  if (! complaint_issued)
-    check_and_convert_grammar ();
-
-  xfclose (gram_in);
 }
 
 
 /*-------------------------------------------------------------.
 | Check the grammar that has just been read, and convert it to |
-| internal form.					       |
+| internal form.                                               |
 `-------------------------------------------------------------*/
 
 static void
@@ -596,9 +669,6 @@ check_and_convert_grammar (void)
   if (nrules == 0)
     fatal (_("no rules in the input grammar"));
 
-  /* Report any undefined symbols and consider them nonterminals.  */
-  symbols_check_defined ();
-
   /* If the user did not define her ENDTOKEN, do it now. */
   if (!endtoken)
     {
@@ -609,6 +679,9 @@ check_and_convert_grammar (void)
       endtoken->user_token_number = 0;
     }
 
+  /* Report any undefined symbols and consider them nonterminals.  */
+  symbols_check_defined ();
+
   /* Find the start symbol if no %start.  */
   if (!start_flag)
     {