X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/e2aaf4c4f98afe4b15ea297d8b0b2b0e210f6fc4..70b7c357476ed3525ddb5d2739e70690cfebb207:/src/reader.c diff --git a/src/reader.c b/src/reader.c index c0702eb0..15392b50 100644 --- a/src/reader.c +++ b/src/reader.c @@ -1,133 +1,167 @@ -/* Input parser for bison - Copyright (C) 1984, 1986, 1989, 1992, 1998, 2000, 2001, 2002 - Free Software Foundation, Inc. +/* Input parser for Bison + + Copyright (C) 1984, 1986, 1989, 1992, 1998, 2000-2003, 2005-2007, + 2009-2013 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., 59 Temple Place - Suite 330, - Boston, MA 02111-1307, USA. */ - + along with this program. If not, see . */ +#include #include "system.h" -#include "quotearg.h" -#include "quote.h" -#include "getargs.h" + +#include + +#include "complain.h" +#include "conflicts.h" #include "files.h" -#include "symtab.h" -#include "symlist.h" +#include "getargs.h" #include "gram.h" -#include "complain.h" -#include "output.h" +#include "muscle-tab.h" #include "reader.h" -#include "conflicts.h" -#include "muscle_tab.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); -int lineno; -static symbol_list_t *grammar = NULL; -static int start_flag = 0; +static symbol_list *grammar = NULL; +static bool start_flag = false; +merger_list *merge_functions; -/* Nonzero if %union has been seen. */ -int typed = 0; +/* Was %union seen? */ +bool union_seen = false; + +/* Was a tag seen? */ +bool tag_seen = false; + +/* Should rules have a default precedence? */ +bool default_prec = true; /*-----------------------. | Set the start symbol. | `-----------------------*/ void -grammar_start_symbol_set (symbol_t *s, location_t l) +grammar_start_symbol_set (symbol *sym, location loc) { if (start_flag) - complain_at (l, _("multiple %s declarations"), "%start"); + complain (&loc, complaint, _("multiple %s declarations"), "%start"); else { - start_flag = 1; - startsymbol = s; - startsymbol_location = l; + start_flag = true; + startsymbol = sym; + startsymbol_location = loc; } } + -/*----------------------------------------------------------------. -| There are two prologues: one before %union, one after. Augment | -| the current one. | -`----------------------------------------------------------------*/ +/*------------------------------------------------------------------------. +| Return the merger index for a merging function named NAME. Records the | +| function, if new, in MERGER_LIST. | +`------------------------------------------------------------------------*/ -void -prologue_augment (const char *prologue, location_t location) +static int +get_merge_function (uniqstr name) { - struct obstack *oout = - !typed ? &pre_prologue_obstack : &post_prologue_obstack; - - if (!no_lines_flag) + merger_list *syms; + merger_list head; + int n; + + if (! glr_parser) + return 0; + + head.next = merge_functions; + for (syms = &head, n = 1; syms->next; syms = syms->next, n += 1) + if (UNIQSTR_EQ (name, syms->next->name)) + break; + if (syms->next == NULL) { - obstack_fgrow2 (oout, muscle_find ("linef"), - location.first_line, - quotearg_style (c_quoting_style, - muscle_find ("filename"))); + syms->next = xmalloc (sizeof syms->next[0]); + syms->next->name = uniqstr_new (name); + /* 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; } - obstack_sgrow (oout, prologue); + 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; -/*----------------------. -| Handle the epilogue. | -`----------------------*/ + if (type == NULL) + type = uniqstr_new (""); -void -epilogue_set (const char *epilogue, location_t location) -{ - if (!no_lines_flag) + 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)) { - obstack_fgrow2 (&muscle_obstack, muscle_find ("linef"), - location.first_line, - quotearg_style (c_quoting_style, - muscle_find ("filename"))); + unsigned indent = 0; + complain_indent (&declaration_loc, complaint, &indent, + _("result type clash on merge function %s: " + "<%s> != <%s>"), + quote (merge_function->name), type, + merge_function->type); + indent += SUB_INDENT; + complain_indent (&merge_function->type_declaration_location, complaint, + &indent, + _("previous declaration")); } - obstack_sgrow (&muscle_obstack, epilogue); - obstack_1grow (&muscle_obstack, 0); - muscle_insert ("epilogue", obstack_finish (&muscle_obstack)); + merge_function->type = uniqstr_new (type); + merge_function->type_declaration_location = declaration_loc; } +/*--------------------------------------. +| Free all merge-function definitions. | +`--------------------------------------*/ - - -/*-------------------------------------------------------------------. -| Generate a dummy symbol, a nonterminal, whose name cannot conflict | -| with the user's names. | -`-------------------------------------------------------------------*/ - -static symbol_t * -gensym (location_t location) +void +free_merger_functions (void) { - /* Incremented for each generated symbol */ - static int gensym_count = 0; - static char buf[256]; - - symbol_t *sym; - - sprintf (buf, "@%d", ++gensym_count); - sym = getsym (buf, location); - sym->class = nterm_sym; - sym->number = nvars++; - return sym; + merger_list *L0 = merge_functions; + while (L0) + { + merger_list *L1 = L0->next; + free (L0); + L0 = L1; + } } + /*-------------------------------------------------------------------. -| Parse the input grammar into a one symbol_list_t structure. Each | +| Parse the input grammar into a one symbol_list structure. Each | | rule is represented by a sequence of symbols: the left hand side | | followed by the contents of the right hand side, followed by a | | null pointer instead of a symbol to terminate the rule. The next | @@ -135,23 +169,16 @@ gensym (location_t location) | | | All actions are copied out, labelled by the rule number they apply | | to. | -| | -| Bison used to allow some %directives in the rules sections, but | -| this is no longer consider appropriate: (i) the documented grammar | -| doesn't claim it, (ii), it would promote bad style, (iii), error | -| recovery for %directives consists in skipping the junk until a `%' | -| is seen and helrp synchronizing. This scheme is definitely wrong | -| in the rules section. | `-------------------------------------------------------------------*/ /* The (currently) last symbol of GRAMMAR. */ -symbol_list_t *grammar_end = NULL; +static symbol_list *grammar_end = NULL; -/* Append S to the GRAMMAR. */ -void -grammar_symbol_append (symbol_t *symbol, location_t location) +/* Append SYM to the grammar. */ +static symbol_list * +grammar_symbol_append (symbol *sym, location loc) { - symbol_list_t *p = symbol_list_new (symbol, location); + symbol_list *p = symbol_list_sym_new (sym, loc); if (grammar_end) grammar_end->next = p; @@ -159,13 +186,37 @@ grammar_symbol_append (symbol_t *symbol, location_t location) grammar = p; grammar_end = p; + + /* A null SYM stands for an end of rule; it is not an actual + 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) + { + complain (&name->loc, Wother, + _("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). */ -symbol_list_t *current_rule = NULL; -symbol_list_t *previous_rule_end = NULL; +static symbol_list *current_rule = NULL; +static symbol_list *previous_rule_end = NULL; /*----------------------------------------------. @@ -173,25 +224,22 @@ symbol_list_t *previous_rule_end = NULL; `----------------------------------------------*/ void -grammar_rule_begin (symbol_t *lhs, location_t location) +grammar_current_rule_begin (symbol *lhs, location loc, + named_ref *lhs_name) { - if (!start_flag) - { - startsymbol = lhs; - startsymbol_location = location; - start_flag = 1; - } + symbol_list* p; /* Start a new rule and record its lhs. */ ++nrules; - ++nritems; - previous_rule_end = grammar_end; - grammar_symbol_append (lhs, location); + + 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. */ - if (lhs->class == unknown_sym) { lhs->class = nterm_sym; @@ -199,41 +247,100 @@ grammar_rule_begin (symbol_t *lhs, location_t location) ++nvars; } else if (lhs->class == token_sym) - complain_at (location, _("rule given for %s, which is a token"), lhs->tag); + complain (&loc, complaint, _("rule given for %s, which is a token"), + lhs->tag); } -/* Check that the last rule (CURRENT_RULE) is properly defined. For - instance, there should be no type clash on the default action. */ + +/*----------------------------------------------------------------------. +| A symbol should be used if either: | +| 1. It has a destructor. | +| 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, bool *midrule_warning) +{ + if (symbol_code_props_get (s->content.sym, destructor)->code) + return true; + 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; +} + +/*----------------------------------------------------------------. +| Check that the rule R is properly defined. For instance, there | +| should be no type clash on the default action. | +`----------------------------------------------------------------*/ static void -grammar_current_rule_check (void) +grammar_rule_check (const symbol_list *r) { - symbol_t *lhs = current_rule->sym; - symbol_t *first_rhs = current_rule->next->sym; + /* Type check. - /* If there is an action, then there is nothing we can do: the user - is allowed to shoot in her foot. */ - if (current_rule->action) - return; + If there is an action, then there is nothing we can do: the user + is allowed to shoot herself in the foot. - /* If $$ is being set in default way, report if any type mismatch. - */ - if (first_rhs) + Don't worry about the default action if $$ is untyped, since $$'s + value can't be used. */ + if (!r->action_props.code && r->content.sym->type_name) { - const char *lhs_type = lhs->type_name ? lhs->type_name : ""; - const char *rhs_type = first_rhs->type_name ? first_rhs->type_name : ""; - if (strcmp (lhs_type, rhs_type)) - complain_at (current_rule->location, - _("type clash (`%s' `%s') on default action"), - lhs_type, rhs_type); - } - /* Warn if there is no default for $$ but we need one. */ - else - { - if (lhs->type_name) - complain_at (current_rule->location, - _("empty rule for typed nonterminal, and no action")); + symbol *first_rhs = r->next->content.sym; + /* If $$ is being set in default way, report if any type mismatch. */ + if (first_rhs) + { + char const *lhs_type = r->content.sym->type_name; + const char *rhs_type = + first_rhs->type_name ? first_rhs->type_name : ""; + if (!UNIQSTR_EQ (lhs_type, rhs_type)) + complain (&r->location, Wother, + _("type clash on default action: <%s> != <%s>"), + lhs_type, rhs_type); + } + /* Warn if there is no default for $$ but we need one. */ + else + complain (&r->location, Wother, + _("empty rule for typed nonterminal, and no action")); } + + /* Check that symbol values that should be used are in fact used. */ + { + symbol_list const *l = r; + int n = 0; + for (; 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, $$ = $1, `uses' both. */ + && (r->action_props.code || (n != 0 && n != 1))) + { + warnings warn_flag = midrule_warning ? Wmidrule_values : Wother; + if (n) + complain (&l->location, warn_flag, _("unused value: $%d"), n); + else + complain (&l->location, warn_flag, _("unset value: $$")); + } + } + } + + /* 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->status != declared && !r->ruleprec->prec) + complain (&r->location, Wother, + _("token for %%prec is not defined: %s"), r->ruleprec->tag); } @@ -242,12 +349,11 @@ grammar_current_rule_check (void) `-------------------------------------*/ void -grammar_rule_end (location_t location) +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 = location; - grammar_current_rule_check (); + current_rule->location = loc; } @@ -267,9 +373,12 @@ grammar_midrule_action (void) /* Make a DUMMY nonterminal, whose location is that of the midrule action. Create the MIDRULE. */ - location_t dummy_location = current_rule->action_location; - symbol_t *dummy = gensym (dummy_location); - symbol_list_t *midrule = symbol_list_new (dummy, dummy_location); + location dummy_location = current_rule->action_props.location; + 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. */ @@ -277,9 +386,12 @@ 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; + code_props_rule_action_init (&midrule->action_props, + current_rule->action_props.code, + current_rule->action_props.location, + midrule, 0, + current_rule->action_props.is_predicate); + code_props_none_init (¤t_rule->action_props); if (previous_rule_end) previous_rule_end->next = midrule; @@ -287,49 +399,101 @@ grammar_midrule_action (void) grammar = midrule; /* End the dummy's rule. */ - previous_rule_end = symbol_list_new (NULL, dummy_location); - previous_rule_end->next = current_rule; + midrule->next = symbol_list_sym_new (NULL, dummy_location); + midrule->next->next = current_rule; - midrule->next = previous_rule_end; + previous_rule_end = midrule->next; /* Insert the dummy nonterminal replacing the midrule action into - the current rule. */ - grammar_current_rule_symbol_append (dummy, dummy_location); + the current rule. Bind it to its dedicated rule. */ + 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. */ void -grammar_current_rule_prec_set (symbol_t *precsym, location_t location) +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 (location, _("two @prec's in a row")); + complain (&loc, complaint, _("only one %s allowed per rule"), "%prec"); current_rule->ruleprec = precsym; } -/* Attach a SYMBOL to the current rule. If needed, move the previous - action as a mid-rule action. */ +/* Attach dynamic precedence DPREC to the current rule. */ void -grammar_current_rule_symbol_append (symbol_t *symbol, location_t location) +grammar_current_rule_dprec_set (int dprec, location loc) { - if (current_rule->action) - grammar_midrule_action (); - ++nritems; - grammar_symbol_append (symbol, location); + if (! glr_parser) + complain (&loc, Wother, _("%s affects only GLR parsers"), + "%dprec"); + if (dprec <= 0) + 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; } +/* Attach a merge function NAME with argument type TYPE to current + rule. */ -/* Attach an ACTION to the current rule. If needed, move the previous +void +grammar_current_rule_merge_set (uniqstr name, location loc) +{ + if (! glr_parser) + 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; +} + +/* Attach SYM to the current rule. If needed, move the previous action as a mid-rule action. */ void -grammar_current_rule_action_append (const char *action, location_t location) +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 (); - current_rule->action = action; - current_rule->action_location = location; + p = grammar_symbol_append (sym, loc); + if (name) + assign_named_ref(p, name); + if (sym->status == undeclared || sym->status == used) + sym->status = needed; +} + +/* Attach an ACTION to the current rule. */ + +void +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, name, is_predicate); } @@ -341,60 +505,92 @@ grammar_current_rule_action_append (const char *action, location_t location) static void packgram (void) { - unsigned int itemno; - int ruleno; - symbol_list_t *p; + unsigned int itemno = 0; + rule_number ruleno = 0; + symbol_list *p = grammar; + + ritem = xnmalloc (nritems + 1, sizeof *ritem); - ritem = XCALLOC (item_number_t, nritems); - rules = XCALLOC (rule_t, nrules) - 1; + /* This sentinel is used by build_relations in gram.c. */ + *ritem++ = 0; - itemno = 0; - ruleno = 1; + rules = xnmalloc (nrules, sizeof *rules); - p = grammar; while (p) { - symbol_t *ruleprec = p->ruleprec; + 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; + rules[ruleno].merger = p->merger; + 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; - - p = p->next; - while (p && p->sym) - { - /* item_number_t = symbol_number_t. - But the former needs to contain more: negative rule numbers. */ - ritem[itemno++] = symbol_number_as_item_number (p->sym->number); - /* A rule gets by default the precedence and associativity - of the last token in it. */ - if (p->sym->class == token_sym) - rules[ruleno].prec = p->sym; - if (p) - p = p->next; - } + 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 + %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; + + /* Don't allow rule_length == INT_MAX, since that might + cause confusion with strtol if INT_MAX == LONG_MAX. */ + if (rule_length == INT_MAX) + complain (&rules[ruleno].location, fatal, _("rule is too long")); + + /* item_number = symbol_number. + But the former needs to contain more: negative rule numbers. */ + 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->content.sym->class == token_sym && default_prec) + rules[ruleno].prec = p->content.sym; + } /* If this rule has a %prec, the specified symbol's precedence replaces the default. */ if (ruleprec) - { - rules[ruleno].precsym = ruleprec; - rules[ruleno].prec = ruleprec; - } - ritem[itemno++] = -ruleno; + { + rules[ruleno].precsym = ruleprec; + rules[ruleno].prec = ruleprec; + } + /* An item ends by the rule number (negated). */ + ritem[itemno++] = rule_number_as_item_number (ruleno); + aver (itemno < ITEM_NUMBER_MAX); ++ruleno; + aver (ruleno < RULE_NUMBER_MAX); if (p) - p = p->next; + p = p->next; } - assert (itemno == nritems); + aver (itemno == nritems); - if (trace_flag) + if (trace_flag & trace_sets) ritem_print (stderr); } @@ -408,88 +604,154 @@ packgram (void) void reader (void) { - gram_control_t gram_control; - lineno = 1; - /* Initialize the symbol table. */ symbols_new (); - /* Construct the axiom symbol. */ - axiom = getsym ("$axiom", empty_location); - axiom->class = nterm_sym; - axiom->number = nvars++; + /* Construct the accept symbol. */ + accept = symbol_get ("$accept", empty_location); + accept->class = nterm_sym; + accept->number = nvars++; /* Construct the error token */ - errtoken = getsym ("error", empty_location); + errtoken = symbol_get ("error", empty_location); errtoken->class = token_sym; errtoken->number = ntokens++; /* Construct a token that represents all undefined literal tokens. It is always token number 2. */ - undeftoken = getsym ("$undefined.", empty_location); + undeftoken = symbol_get ("$undefined", empty_location); 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 (); - finput = xfopen (infile, "r"); - gram_in = finput; + if (complaint_status < status_complaint) + 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-state", "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 (STRNEQ (lr_type, "canonical-lr")) + muscle_percent_define_default ("lr.default-reduction", "most"); + else + muscle_percent_define_default ("lr.default-reduction", "accepting"); + free (lr_type); + } + + /* Check %define front-end variables. */ + { + static char const * const values[] = { + "lr.type", "lalr", "ielr", "canonical-lr", NULL, + "lr.default-reduction", "most", "consistent", "accepting", NULL, + NULL + }; + muscle_percent_define_check_values (values); + } +} - gram_debug = !!getenv ("parse"); - gram__flex_debug = !!getenv ("scan"); - scanner_initialize (); - gram_parse (&gram_control); - /* Grammar has been read. Do some checking */ +/*-------------------------------------------------------------. +| Check the grammar that has just been read, and convert it to | +| internal form. | +`-------------------------------------------------------------*/ + +static void +check_and_convert_grammar (void) +{ + /* Grammar has been read. Do some checking. */ if (nrules == 0) - fatal (_("no rules in the input grammar")); + complain (NULL, fatal, _("no rules in the input grammar")); + + /* If the user did not define her ENDTOKEN, do it now. */ + if (!endtoken) + { + endtoken = symbol_get ("$end", empty_location); + endtoken->class = token_sym; + endtoken->number = 0; + /* Value specified by POSIX. */ + endtoken->user_token_number = 0; + } /* Report any undefined symbols and consider them nonterminals. */ symbols_check_defined (); - /* If the user did not define her EOFTOKEN, do it now. */ - if (!eoftoken) + /* Find the start symbol if no %start. */ + if (!start_flag) { - eoftoken = getsym ("$", empty_location); - eoftoken->class = token_sym; - eoftoken->number = 0; - /* Value specified by POSIX. */ - eoftoken->user_token_number = 0; + 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, which line is that of the first rule + /* Insert the initial rule, whose line is that of the first rule (not that of the start symbol): - axiom: %start EOF. */ + accept: %start EOF. */ { - symbol_list_t *p = symbol_list_new (axiom, 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 (eoftoken, 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; } - if (nsyms > SHRT_MAX) - fatal (_("too many symbols (tokens plus nonterminals); maximum %d"), - SHRT_MAX); - - assert (nsyms == ntokens + nvars); - - xfclose (finput); + 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_t is no longer needed. */ - LIST_FREE (symbol_list_t, grammar); + /* The grammar as a symbol_list is no longer needed. */ + symbol_list_free (grammar); }