X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/e256e17f572408a91d2014d6b8be1b11e5910b40..8bb3a2e7dfd705ff7cb78fb12028557a92b4feaf:/src/reader.c diff --git a/src/reader.c b/src/reader.c index 2c05c19a..250e4f8b 100644 --- a/src/reader.c +++ b/src/reader.c @@ -1,29 +1,27 @@ /* Input parser for Bison Copyright (C) 1984, 1986, 1989, 1992, 1998, 2000, 2001, 2002, 2003, - 2005, 2006 Free Software Foundation, Inc. + 2005, 2006, 2007, 2009 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 #include "complain.h" @@ -31,13 +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; @@ -45,7 +44,10 @@ static bool start_flag = false; merger_list *merge_functions; /* Was %union seen? */ -bool typed = false; +bool union_seen = false; + +/* Was a tag seen? */ +bool tag_seen = false; /* Should rules have a default precedence? */ bool default_prec = true; @@ -67,37 +69,15 @@ 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); -} - -/*-------------------------------------------------------------------. -| Return the merger index for a merging function named NAME, whose | -| arguments have type TYPE. Records the function, if new, in | -| MERGER_LIST. | -`-------------------------------------------------------------------*/ +/*------------------------------------------------------------------------. +| Return the merger index for a merging function named NAME. Records the | +| function, if new, in MERGER_LIST. | +`------------------------------------------------------------------------*/ static int -get_merge_function (uniqstr name, uniqstr type, location loc) +get_merge_function (uniqstr name) { merger_list *syms; merger_list head; @@ -106,9 +86,6 @@ get_merge_function (uniqstr name, uniqstr type, location loc) if (! glr_parser) return 0; - if (type == NULL) - type = uniqstr_new (""); - head.next = merge_functions; for (syms = &head, n = 1; syms->next; syms = syms->next, n += 1) if (UNIQSTR_EQ (name, syms->next->name)) @@ -117,16 +94,51 @@ get_merge_function (uniqstr name, uniqstr type, location loc) { syms->next = xmalloc (sizeof syms->next[0]); syms->next->name = uniqstr_new (name); - syms->next->type = uniqstr_new (type); + /* After all symbol type declarations have been parsed, packgram invokes + record_merge_function_type to set the type. */ + syms->next->type = NULL; syms->next->next = NULL; merge_functions = head.next; } - else if (!UNIQSTR_EQ (type, syms->next->type)) - warn_at (loc, _("result type clash on merge function %s: <%s> != <%s>"), - name, type, syms->next->type); return n; } +/*-------------------------------------------------------------------------. +| For the existing merging function with index MERGER, record the result | +| type as TYPE as required by the lhs of the rule whose %merge declaration | +| is at DECLARATION_LOC. | +`-------------------------------------------------------------------------*/ + +static void +record_merge_function_type (int merger, uniqstr type, location declaration_loc) +{ + int merger_find; + merger_list *merge_function; + + if (merger <= 0) + return; + + if (type == NULL) + type = uniqstr_new (""); + + merger_find = 1; + for (merge_function = merge_functions; + merge_function != NULL && merger_find != merger; + merge_function = merge_function->next) + merger_find += 1; + aver (merge_function != NULL && merger_find == merger); + 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); + complain_at (merge_function->type_declaration_location, + _("previous declaration")); + } + merge_function->type = uniqstr_new (type); + merge_function->type_declaration_location = declaration_loc; +} + /*--------------------------------------. | Free all merge-function definitions. | `--------------------------------------*/ @@ -159,10 +171,10 @@ 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_new (sym, loc); + symbol_list *p = symbol_list_sym_new (sym, loc); if (grammar_end) grammar_end->next = p; @@ -175,8 +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). */ @@ -189,19 +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) { - if (!start_flag) - { - startsymbol = lhs; - startsymbol_location = loc; - start_flag = true; - } + 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, lhs_name); + current_rule = grammar_end; /* Mark the rule's lhs as a nonterminal if not already so. */ @@ -217,16 +248,25 @@ grammar_current_rule_begin (symbol *lhs, location loc) /*----------------------------------------------------------------------. -| A symbol should be used if it has a destructor, or if it is a | -| mid-rule symbol (i.e., the generated LHS replacing a mid-rule | -| action) that was assigned to, as in "exp: { $$ = 1; } { $$ = $1; }". | +| 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; }". | `----------------------------------------------------------------------*/ static bool symbol_should_be_used (symbol_list const *s) { - return (s->sym->destructor - || (s->midrule && s->midrule->used)); + 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)); + return false; } /*----------------------------------------------------------------. @@ -244,13 +284,13 @@ grammar_rule_check (const symbol_list *r) Don't worry about the default action if $$ is untyped, since $$'s value can't be used. */ - if (!r->action && r->sym->type_name) + if (!r->action_props.code && r->content.sym->type_name) { - symbol *first_rhs = r->next->sym; + symbol *first_rhs = r->next->content.sym; /* If $$ is being set in default way, report if any type mismatch. */ if (first_rhs) { - char const *lhs_type = r->sym->type_name; + char const *lhs_type = r->content.sym->type_name; const char *rhs_type = first_rhs->type_name ? first_rhs->type_name : ""; if (!UNIQSTR_EQ (lhs_type, rhs_type)) @@ -268,11 +308,11 @@ grammar_rule_check (const symbol_list *r) { symbol_list const *l = r; int n = 0; - for (; l && l->sym; l = l->next, ++n) - if (! (l->used + for (; l && l->content.sym; l = l->next, ++n) + if (! (l->action_props.is_value_used || !symbol_should_be_used (l) /* The default action, $$ = $1, `uses' both. */ - || (!r->action && (n == 0 || n == 1)))) + || (!r->action_props.code && (n == 0 || n == 1)))) { if (n) warn_at (r->location, _("unused value: $%d"), n); @@ -280,6 +320,15 @@ grammar_rule_check (const symbol_list *r) warn_at (r->location, _("unset value: $$")); } } + + /* See comments in grammar_current_rule_prec_set for how POSIX + mandates this complaint. It's only for identifiers, so skip + it for char literals and strings, which are always tokens. */ + if (r->ruleprec + && r->ruleprec->tag[0] != '\'' && r->ruleprec->tag[0] != '"' + && !r->ruleprec->declared && !r->ruleprec->prec) + warn_at (r->location, _("token for %%prec is not defined: %s"), + r->ruleprec->tag); } @@ -293,7 +342,6 @@ grammar_current_rule_end (location loc) /* Put an empty link in the list to mark the end of this rule */ grammar_symbol_append (NULL, grammar_end->location); current_rule->location = loc; - grammar_rule_check (current_rule); } @@ -313,9 +361,12 @@ grammar_midrule_action (void) /* Make a DUMMY nonterminal, whose location is that of the midrule action. Create the MIDRULE. */ - location dummy_location = current_rule->action_location; + location dummy_location = current_rule->action_props.location; symbol *dummy = dummy_symbol_get (dummy_location); - symbol_list *midrule = symbol_list_new (dummy, dummy_location); + symbol_list *midrule = symbol_list_sym_new (dummy, dummy_location); + + /* Remember named_ref of previous action. */ + named_ref *action_name = current_rule->action_props.named_ref; /* Make a new rule, whose body is empty, before the current one, so that the action just read can belong to it. */ @@ -323,13 +374,11 @@ grammar_midrule_action (void) ++nritems; /* Attach its location and actions to that of the DUMMY. */ midrule->location = dummy_location; - midrule->action = current_rule->action; - midrule->action_location = dummy_location; - current_rule->action = NULL; - /* If $$ was used in the action, the LHS of the enclosing rule was - incorrectly flagged as used. */ - midrule->used = current_rule->used; - current_rule->used = false; + code_props_rule_action_init (&midrule->action_props, + current_rule->action_props.code, + current_rule->action_props.location, + midrule, 0); + code_props_none_init (¤t_rule->action_props); if (previous_rule_end) previous_rule_end->next = midrule; @@ -337,16 +386,18 @@ grammar_midrule_action (void) grammar = midrule; /* End the dummy's rule. */ - midrule->next = symbol_list_new (NULL, dummy_location); - grammar_rule_check (midrule); + midrule->next = symbol_list_sym_new (NULL, dummy_location); midrule->next->next = current_rule; previous_rule_end = midrule->next; /* 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); } /* Set the precedence symbol of the current rule to PRECSYM. */ @@ -354,6 +405,17 @@ 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"); current_rule->ruleprec = precsym; @@ -383,31 +445,37 @@ grammar_current_rule_merge_set (uniqstr name, location loc) warn_at (loc, _("%s affects only GLR parsers"), "%merge"); if (current_rule->merger != 0) complain_at (loc, _("only one %s allowed per rule"), "%merge"); - current_rule->merger = - get_merge_function (name, current_rule->sym->type_name, loc); + current_rule->merger = get_merge_function (name); + current_rule->merger_declaration_location = loc; } /* Attach SYM to the current rule. If needed, move the previous 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) { - if (current_rule->action) + 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) + if (current_rule->action_props.code) grammar_midrule_action (); - current_rule->action = action; - current_rule->action_location = loc; - current_rule->action = translate_rule_action (current_rule); + /* 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, name); } @@ -434,9 +502,11 @@ 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); rules[ruleno].user_number = ruleno; rules[ruleno].number = ruleno; - rules[ruleno].lhs = p->sym; + rules[ruleno].lhs = p->content.sym; rules[ruleno].rhs = ritem + itemno; rules[ruleno].prec = NULL; rules[ruleno].dprec = p->dprec; @@ -444,10 +514,26 @@ packgram (void) rules[ruleno].precsym = NULL; rules[ruleno].location = p->location; rules[ruleno].useful = true; - rules[ruleno].action = p->action; - rules[ruleno].action_location = p->action_location; - - for (p = p->next; p && p->sym; p = p->next) + rules[ruleno].action = p->action_props.code; + rules[ruleno].action_location = p->action_props.location; + + /* 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 + && (p->action_props.is_value_used + || symbol_list_n_get (p->midrule_parent_rule, + p->midrule_parent_rhs_index) + ->action_props.is_value_used)) + 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. */ + if (p != grammar) + grammar_rule_check (p); + + for (p = p->next; p && p->content.sym; p = p->next) { ++rule_length; @@ -458,11 +544,12 @@ packgram (void) /* item_number = symbol_number. But the former needs to contain more: negative rule numbers. */ - ritem[itemno++] = symbol_number_as_item_number (p->sym->number); + 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->sym->class == token_sym && default_prec) - rules[ruleno].prec = p->sym; + if (p->content.sym->class == token_sym && default_prec) + rules[ruleno].prec = p->content.sym; } /* If this rule has a %prec, @@ -474,15 +561,15 @@ packgram (void) } /* An item ends by the rule number (negated). */ ritem[itemno++] = rule_number_as_item_number (ruleno); - assert (itemno < ITEM_NUMBER_MAX); + aver (itemno < ITEM_NUMBER_MAX); ++ruleno; - assert (ruleno < RULE_NUMBER_MAX); + aver (ruleno < RULE_NUMBER_MAX); if (p) p = p->next; } - assert (itemno == nritems); + aver (itemno == nritems); if (trace_flag & trace_sets) ritem_print (stderr); @@ -517,16 +604,13 @@ 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 (); @@ -534,6 +618,35 @@ 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", "all"); + 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", "all", "consistent", "accepting", NULL, + NULL + }; + muscle_percent_define_check_values (values); + } +} + /*-------------------------------------------------------------. | Check the grammar that has just been read, and convert it to | @@ -547,9 +660,6 @@ 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) { @@ -560,31 +670,69 @@ 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) + { + symbol_list *node; + for (node = grammar; + node != NULL && symbol_is_dummy (node->content.sym); + node = node->next) + { + for (node = node->next; + node != NULL && node->content.sym != NULL; + node = node->next) + ; + } + aver (node != NULL); + grammar_start_symbol_set (node->content.sym, + node->content.sym->location); + } + /* Insert the initial rule, whose line is that of the first rule (not that of the start symbol): accept: %start EOF. */ { - symbol_list *p = symbol_list_new (accept, empty_location); + symbol_list *p = symbol_list_sym_new (accept, empty_location); p->location = grammar->location; - p->next = symbol_list_new (startsymbol, empty_location); - p->next->next = symbol_list_new (endtoken, empty_location); - p->next->next->next = symbol_list_new (NULL, empty_location); + p->next = symbol_list_sym_new (startsymbol, empty_location); + p->next->next = symbol_list_sym_new (endtoken, empty_location); + p->next->next->next = symbol_list_sym_new (NULL, empty_location); p->next->next->next->next = grammar; nrules += 1; nritems += 3; grammar = p; } - assert (nsyms <= SYMBOL_NUMBER_MAXIMUM && nsyms == ntokens + nvars); + aver (nsyms <= SYMBOL_NUMBER_MAXIMUM && nsyms == ntokens + nvars); /* Assign the symbols their symbol numbers. Write #defines for the 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 (); /* The grammar as a symbol_list is no longer needed. */ - LIST_FREE (symbol_list, grammar); + symbol_list_free (grammar); }