/* Input parser for Bison
- Copyright (C) 1984, 1986, 1989, 1992, 1998, 2000, 2001, 2002, 2003,
- 2005, 2006, 2007 Free Software Foundation, Inc.
+ Copyright (C) 1984, 1986, 1989, 1992, 1998, 2000-2003, 2005-2007,
+ 2009-2011 Free Software Foundation, Inc.
This file is part of Bison, the GNU Compiler Compiler.
#include <config.h>
#include "system.h"
+#include <quote.h>
#include <quotearg.h>
#include "complain.h"
#include "files.h"
#include "getargs.h"
#include "gram.h"
-#include "muscle_tab.h"
+#include "muscle-tab.h"
#include "reader.h"
#include "symlist.h"
#include "symtab.h"
#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;
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);
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). */
`----------------------------------------------*/
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. */
/*----------------------------------------------------------------------.
| 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;
}
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);
}
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;
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 (¤t_rule->action_props);
if (previous_rule_end)
/* 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);
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");
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 (¤t_rule->action_props, action, loc,
- current_rule);
+ current_rule, name, is_predicate);
}
\f
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
gram_debug = trace_flag & trace_parse;
gram_scanner_initialize ();
gram_parse ();
+ prepare_percent_define_front_end_variables ();
if (! complaint_issued)
check_and_convert_grammar ();
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;
+ /* 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-reductions", "most");
+ else
+ muscle_percent_define_default ("lr.default-reductions", "accepting");
+ free (lr_type);
+ }
+
+ /* Check %define front-end variables. */
+ {
+ static char const * const values[] = {
+ "lr.type", "lalr", "ielr", "canonical-lr", NULL,
+ "lr.default-reductions", "most", "consistent", "accepting", NULL,
+ NULL
+ };
+ muscle_percent_define_check_values (values);
+ }
+}
+
/*-------------------------------------------------------------.
| Check the grammar that has just been read, and convert it to |
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)
{
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)
{
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