X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/06505b0c69485c906ed183dcf200d11fd6fce400..3209eb1c4c5de8dd812e65da27df00c548f476fe:/src/reader.c diff --git a/src/reader.c b/src/reader.c index de501a13..f2e12c6b 100644 --- a/src/reader.c +++ b/src/reader.c @@ -1,7 +1,7 @@ /* Input parser for Bison Copyright (C) 1984, 1986, 1989, 1992, 1998, 2000-2003, 2005-2007, - 2009-2013 Free Software Foundation, Inc. + 2009-2015 Free Software Foundation, Inc. This file is part of Bison, the GNU Compiler Compiler. @@ -321,7 +321,7 @@ grammar_rule_check (const symbol_list *r) bool midrule_warning = false; if (!l->action_props.is_value_used && symbol_should_be_used (l, &midrule_warning) - /* The default action, $$ = $1, `uses' both. */ + /* The default action, $$ = $1, 'uses' both. */ && (r->action_props.code || (n != 0 && n != 1))) { warnings warn_flag = midrule_warning ? Wmidrule_values : Wother; @@ -333,6 +333,18 @@ grammar_rule_check (const symbol_list *r) } } + /* Check that %empty => empty rule. */ + if (r->percent_empty_loc.start.file + && r->next && r->next->content.sym) + complain (&r->percent_empty_loc, complaint, + _("%%empty on non-empty rule")); + + /* Check that empty rule => %empty. */ + if (!(r->next && r->next->content.sym) + && !r->midrule_parent_rule + && !r->percent_empty_loc.start.file) + complain (&r->location, Wempty_rule, _("empty rule without %%empty")); + /* 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. */ @@ -430,8 +442,26 @@ grammar_current_rule_prec_set (symbol *precsym, location loc) token. */ symbol_class_set (precsym, token_sym, loc, false); if (current_rule->ruleprec) - complain (&loc, complaint, _("only one %s allowed per rule"), "%prec"); - current_rule->ruleprec = precsym; + duplicate_directive ("%prec", + current_rule->ruleprec->location, loc); + else + current_rule->ruleprec = precsym; +} + +/* Set %empty for the current rule. */ + +void +grammar_current_rule_empty_set (location loc) +{ + /* If %empty is used and -Wno-empty-rule is not, then enable + -Wempty-rule. */ + if (warning_is_unset (Wempty_rule)) + warning_argmatch ("empty-rule", 0, 0); + if (current_rule->percent_empty_loc.start.file) + duplicate_directive ("%empty", + current_rule->percent_empty_loc, loc); + else + current_rule->percent_empty_loc = loc; } /* Attach dynamic precedence DPREC to the current rule. */ @@ -446,8 +476,13 @@ grammar_current_rule_dprec_set (int dprec, location loc) complain (&loc, complaint, _("%s must be followed by positive number"), "%dprec"); else if (current_rule->dprec != 0) - complain (&loc, complaint, _("only one %s allowed per rule"), "%dprec"); - current_rule->dprec = dprec; + duplicate_directive ("%dprec", + current_rule->dprec_location, loc); + else + { + current_rule->dprec = dprec; + current_rule->dprec_location = loc; + } } /* Attach a merge function NAME with argument type TYPE to current @@ -460,9 +495,13 @@ grammar_current_rule_merge_set (uniqstr name, location loc) complain (&loc, Wother, _("%s affects only GLR parsers"), "%merge"); if (current_rule->merger != 0) - complain (&loc, complaint, _("only one %s allowed per rule"), "%merge"); - current_rule->merger = get_merge_function (name); - current_rule->merger_declaration_location = loc; + duplicate_directive ("%merge", + current_rule->merger_declaration_location, loc); + else + { + current_rule->merger = get_merge_function (name); + current_rule->merger_declaration_location = loc; + } } /* Attach SYM to the current rule. If needed, move the previous @@ -477,7 +516,7 @@ grammar_current_rule_symbol_append (symbol *sym, location loc, grammar_midrule_action (); p = grammar_symbol_append (sym, loc); if (name) - assign_named_ref(p, name); + assign_named_ref (p, name); if (sym->status == undeclared || sym->status == used) sym->status = needed; } @@ -535,7 +574,7 @@ packgram (void) rules[ruleno].action_location = p->action_props.location; rules[ruleno].is_predicate = p->action_props.is_predicate; - /* If the midrule's $$ is set or its $n is used, remove the `$' from the + /* If the midrule's $$ 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. */ if (p->midrule_parent_rule @@ -712,7 +751,7 @@ check_and_convert_grammar (void) /* Insert the initial rule, whose line is that of the first rule (not that of the start symbol): - accept: %start EOF. */ + $accept: %start $end. */ { symbol_list *p = symbol_list_sym_new (accept, empty_location); p->location = grammar->location; @@ -725,7 +764,8 @@ check_and_convert_grammar (void) grammar = p; } - aver (nsyms <= SYMBOL_NUMBER_MAXIMUM && nsyms == ntokens + nvars); + aver (nsyms <= SYMBOL_NUMBER_MAXIMUM); + aver (nsyms == ntokens + nvars); /* Assign the symbols their symbol numbers. Write #defines for the token symbols into FDEFINES if requested. */ @@ -736,11 +776,11 @@ check_and_convert_grammar (void) action type checking. Before invoking grammar_rule_check (in packgram below) on any rule, make - sure all actions have already been scanned in order to set `used' flags. + sure all actions have already been scanned in order to set 'used' flags. Otherwise, checking that a midrule's $$ should be set will not always work properly because the check must forward-reference the midrule's parent - rule. For the same reason, all the `used' flags must be set before - checking whether to remove `$' from any midrule symbol name (also in + rule. For the same reason, all the 'used' flags must be set before + checking whether to remove '$' from any midrule symbol name (also in packgram). */ { symbol_list *sym;