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multistart: adjust reader checks for generated rules

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So far we were not checking the generated rule 0 at all.  Now there
can be several of them.  Instead of not checking at all, let's be more
selective on the check to run on them.

* src/reader.c (grammar_rule_check_and_complete): Don't check for
value usage for generated rules, it is ok to have a valued start
symbol, in which case it is ok for the generated rule ("accept: start
$end {}") to not use $1.
(packgram): Call grammar_rule_check_and_complete for all the rules.
This commit is contained in:
Akim Demaille
2020-07-05 07:56:04 +02:00
parent a0b044186b
commit a6805bb8d9
1 changed files with 27 additions and 26 deletions
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53
src/reader.c
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@@ -266,6 +266,7 @@ symbol_should_be_used (symbol_list const *s, bool *midrule_warning)
static void
grammar_rule_check_and_complete (symbol_list *r)
{
const symbol *lhs = r->content.sym;
/* Type check.
If there is an action, then there is nothing we can do: the user
@@ -273,13 +274,13 @@ grammar_rule_check_and_complete (symbol_list *r)
Don't worry about the default action if $$ is untyped, since $$'s
value can't be used. */
if (!r->action_props.code && r->content.sym->content->type_name)
if (!r->action_props.code && lhs->content->type_name)
{
symbol *first_rhs = r->next->content.sym;
/* If $$ is being set in default way, report if any type mismatch. */
if (first_rhs)
{
char const *lhs_type = r->content.sym->content->type_name;
char const *lhs_type = lhs->content->type_name;
char const *rhs_type =
first_rhs->content->type_name ? first_rhs->content->type_name : "";
if (!UNIQSTR_EQ (lhs_type, rhs_type))
@@ -311,25 +312,29 @@ grammar_rule_check_and_complete (symbol_list *r)
_("empty rule for typed nonterminal, and no action"));
}
/* Check that symbol values that should be used are in fact used. */
{
int n = 0;
for (symbol_list const *l = r; l && l->content.sym; l = l->next, ++n)
{
bool midrule_warning = false;
if (!l->action_props.is_value_used
&& symbol_should_be_used (l, &midrule_warning)
/* The default action, $$ = $1, 'uses' both. */
&& (r->action_props.code || (n != 0 && n != 1)))
{
warnings warn_flag = midrule_warning ? Wmidrule_values : Wother;
if (n)
complain (&l->sym_loc, warn_flag, _("unused value: $%d"), n);
else
complain (&l->rhs_loc, warn_flag, _("unset value: $$"));
}
}
}
/* Check that symbol values that should be used are in fact used.
Don't check the generated start rules. It has no action, so some
rhs symbols may appear unused, but the parsing algorithm ensures
that %destructor's are invoked appropriately. */
if (lhs != acceptsymbol)
{
int n = 0;
for (symbol_list const *l = r; l && l->content.sym; l = l->next, ++n)
{
bool midrule_warning = false;
if (!l->action_props.is_value_used
&& symbol_should_be_used (l, &midrule_warning)
/* The default action, $$ = $1, 'uses' both. */
&& (r->action_props.code || (n != 0 && n != 1)))
{
warnings warn_flag = midrule_warning ? Wmidrule_values : Wother;
if (n)
complain (&l->sym_loc, warn_flag, _("unused value: $%d"), n);
else
complain (&l->rhs_loc, warn_flag, _("unset value: $$"));
}
}
}
/* Check that %empty => empty rule. */
if (r->percent_empty_loc.start.file
@@ -624,11 +629,7 @@ packgram (void)
->action_props.is_value_used)))
lhs->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. */
if (lhs != grammar)
grammar_rule_check_and_complete (lhs);
grammar_rule_check_and_complete (lhs);
rules[ruleno].code = ruleno;
rules[ruleno].number = ruleno;