X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/95021767a1e93fa7b83f8a6c5ec5fd5f8064dd2c..8ffd7912e3b71fb0cc69e83225c3ad8e3452270f:/src/reader.c diff --git a/src/reader.c b/src/reader.c index 587a4f09..92db5717 100644 --- a/src/reader.c +++ b/src/reader.c @@ -1,28 +1,27 @@ /* 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. - Bison is free software; you can redistribute it and/or modify + This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by - the Free Software Foundation; either version 2, or (at your option) - any later version. + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. - Bison is distributed in the hope that it will be useful, + This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License - along with Bison; see the file COPYING. If not, write to - the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, - Boston, MA 02110-1301, USA. */ + along with this program. If not, see . */ #include #include "system.h" +#include #include #include "complain.h" @@ -30,13 +29,14 @@ #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; @@ -69,27 +69,6 @@ grammar_start_symbol_set (symbol *sym, location loc) } } - -/*---------------------------------------------------------------------. -| There are two prologues: one before the first %union and one after. | -| Augment the one specified by POST. | -`---------------------------------------------------------------------*/ - -void -prologue_augment (const char *prologue, location loc, bool post) -{ - struct obstack *oout = - !post ? &pre_prologue_obstack : &post_prologue_obstack; - - obstack_fgrow1 (oout, "]b4_syncline(%d, [[", loc.start.line); - /* FIXME: Protection of M4 characters missing here. See - output.c:escaped_output. */ - MUSCLE_OBSTACK_SGROW (oout, - quotearg_style (c_quoting_style, loc.start.file)); - obstack_sgrow (oout, "]])[\n"); - obstack_sgrow (oout, prologue); -} - /*------------------------------------------------------------------------. @@ -192,7 +171,7 @@ 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); @@ -208,8 +187,27 @@ 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). */ @@ -222,12 +220,19 @@ 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. */ @@ -245,22 +250,25 @@ 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; } @@ -304,17 +312,31 @@ 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); } @@ -351,6 +373,9 @@ 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; @@ -360,7 +385,7 @@ 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); code_props_none_init (¤t_rule->action_props); if (previous_rule_end) @@ -376,7 +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); @@ -387,6 +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"); @@ -425,24 +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) { 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); } @@ -465,20 +506,6 @@ packgram (void) rules = xnmalloc (nrules, sizeof *rules); - /* Before invoking grammar_rule_check on any rule, make 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. */ - while (p) - { - code_props_translate_code (&p->action_props); - if (p) - p = p->next; - } - - p = grammar; while (p) { int rule_length = 0; @@ -585,16 +612,13 @@ reader (void) undeftoken->class = token_sym; undeftoken->number = ntokens++; - /* Initialize the obstacks. */ - obstack_init (&pre_prologue_obstack); - obstack_init (&post_prologue_obstack); - gram_in = xfopen (grammar_file, "r"); gram__flex_debug = trace_flag & trace_scan; gram_debug = trace_flag & trace_parse; gram_scanner_initialize (); gram_parse (); + prepare_percent_define_front_end_variables (); if (! complaint_issued) check_and_convert_grammar (); @@ -602,6 +626,35 @@ reader (void) 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 | @@ -615,9 +668,6 @@ 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) { @@ -628,6 +678,9 @@ 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) { @@ -668,6 +721,23 @@ check_and_convert_grammar (void) token symbols into FDEFINES if requested. */ symbols_pack (); + /* Scan rule actions after invoking symbol_check_alias_consistency (in + symbols_pack above) so that token types are set correctly before the rule + 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. + 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 + packgram). */ + { + symbol_list *sym; + for (sym = grammar; sym; sym = sym->next) + code_props_translate_code (&sym->action_props); + } + /* Convert the grammar into the format described in gram.h. */ packgram ();