/* Input parser for Bison
- Copyright (C) 1984, 1986, 1989, 1992, 1998, 2000, 2001, 2002, 2003
- Free Software Foundation, Inc.
+ Copyright (C) 1984, 1986, 1989, 1992, 1998, 2000, 2001, 2002, 2003,
+ 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., 59 Temple Place - Suite 330,
- Boston, MA 02111-1307, USA. */
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+#include <config.h>
#include "system.h"
+#include <quote.h>
#include <quotearg.h>
#include "complain.h"
#include "files.h"
#include "getargs.h"
#include "gram.h"
-#include "muscle_tab.h"
-#include "output.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;
static bool start_flag = false;
merger_list *merge_functions;
-/* Has %union been seen? */
-bool typed = false;
+/* 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;
}
}
-
-/*----------------------------------------------------------------.
-| There are two prologues: one before %union, one after. Augment |
-| the current one. |
-`----------------------------------------------------------------*/
-
-void
-prologue_augment (const char *prologue, location loc)
-{
- struct obstack *oout =
- !typed ? &pre_prologue_obstack : &post_prologue_obstack;
-
- obstack_fgrow1 (oout, "]b4_syncline([[%d]], [[", loc.start.line);
- MUSCLE_OBSTACK_SGROW (oout,
- quotearg_style (c_quoting_style, loc.start.file));
- obstack_sgrow (oout, "]])[\n");
- obstack_sgrow (oout, prologue);
-}
-
\f
-/*-------------------------------------------------------------------.
-| 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;
if (! glr_parser)
return 0;
- if (type == NULL)
- type = uniqstr_new ("");
-
head.next = merge_functions;
- for (syms = &head, n = 1; syms->next != NULL; syms = syms->next, n += 1)
+ for (syms = &head, n = 1; syms->next; syms = syms->next, n += 1)
if (UNIQSTR_EQ (name, syms->next->name))
break;
if (syms->next == NULL)
{
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. |
`--------------------------------------*/
void
free_merger_functions (void)
{
- merger_list *L0;
- if (! glr_parser)
- return;
- L0 = merge_functions;
- while (L0 != NULL)
+ merger_list *L0 = merge_functions;
+ while (L0)
{
merger_list *L1 = L0->next;
free (L0);
| |
| 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 *grammar_end = NULL;
+static symbol_list *grammar_end = NULL;
/* Append SYM to the grammar. */
-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;
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)
+ {
+ 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). */
-symbol_list *current_rule = NULL;
-symbol_list *previous_rule_end = NULL;
+static symbol_list *current_rule = NULL;
+static symbol_list *previous_rule_end = NULL;
/*----------------------------------------------.
`----------------------------------------------*/
void
-grammar_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;
- ++nritems;
-
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. */
-
if (lhs->class == unknown_sym)
{
lhs->class = nterm_sym;
complain_at (loc, _("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. --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)
+{
+ 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;
+}
+
+/*----------------------------------------------------------------.
+| 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 *lhs = current_rule->sym;
- char const *lhs_type = lhs->type_name;
- symbol *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 herself in the 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.
- /* Don't worry about the default action if $$ is untyped, since $$'s
+ Don't worry about the default action if $$ is untyped, since $$'s
value can't be used. */
- if (! lhs_type)
- return;
-
- /* If $$ is being set in default way, report if any type mismatch. */
- if (first_rhs)
+ if (!r->action_props.code && r->content.sym->type_name)
{
- const char *rhs_type = first_rhs->type_name ? first_rhs->type_name : "";
- if (!UNIQSTR_EQ (lhs_type, rhs_type))
- warn_at (current_rule->location,
- _("type clash on default action: <%s> != <%s>"),
- lhs_type, rhs_type);
+ symbol *first_rhs = r->next->content.sym;
+ /* If $$ 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))
+ warn_at (r->location,
+ _("type clash on default action: <%s> != <%s>"),
+ lhs_type, rhs_type);
+ }
+ /* Warn if there is no default for $$ but we need one. */
+ else
+ warn_at (r->location,
+ _("empty rule for typed nonterminal, and no action"));
}
- /* Warn if there is no default for $$ but we need one. */
- else
- warn_at (current_rule->location,
- _("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)
+ if (! (l->action_props.is_value_used
+ || !symbol_should_be_used (l)
+ /* The default action, $$ = $1, `uses' both. */
+ || (!r->action_props.code && (n == 0 || n == 1))))
+ {
+ if (n)
+ warn_at (r->location, _("unused value: $%d"), n);
+ else
+ warn_at (r->location, _("unset value: $$"));
+ }
+ }
}
`-------------------------------------*/
void
-grammar_rule_end (location loc)
+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_current_rule_check ();
}
/* 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. */
++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);
+ code_props_none_init (¤t_rule->action_props);
if (previous_rule_end)
previous_rule_end->next = midrule;
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 *precsym, location loc)
{
+ 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;
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 ();
- ++nritems;
- 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. If needed, move the previous
- action as a mid-rule action. */
+/* 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;
+ /* 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);
}
\f
rule_number ruleno = 0;
symbol_list *p = grammar;
- ritem = xnmalloc (nritems, sizeof *ritem);
+ ritem = xnmalloc (nritems + 1, sizeof *ritem);
+
+ /* This sentinel is used by build_relations in gram.c. */
+ *ritem++ = 0;
+
rules = xnmalloc (nrules, sizeof *rules);
while (p)
{
+ 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].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)
+ 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;
+
+ /* Don't allow rule_length == INT_MAX, since that might
+ cause confusion with strtol if INT_MAX == LONG_MAX. */
+ if (rule_length == INT_MAX)
+ fatal_at (rules[ruleno].location, _("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->sym->number);
+ ritem[itemno++] =
+ symbol_number_as_item_number (p->content.sym->number);
/* A rule gets by default the precedence and associativity
- of the last token in it. */
- if (p->sym->class == token_sym && default_prec)
- rules[ruleno].prec = p->sym;
- if (p)
- p = p->next;
+ 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,
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;
}
- if (itemno != nritems)
- abort ();
+ aver (itemno == nritems);
if (trace_flag & trace_sets)
ritem_print (stderr);
undeftoken->class = token_sym;
undeftoken->number = ntokens++;
- /* Initialize the obstacks. */
- obstack_init (&pre_prologue_obstack);
- obstack_init (&post_prologue_obstack);
-
- finput = xfopen (grammar_file, "r");
- gram_in = finput;
+ gram_in = xfopen (grammar_file, "r");
gram__flex_debug = trace_flag & trace_scan;
gram_debug = trace_flag & trace_parse;
- scanner_initialize ();
+ gram_scanner_initialize ();
gram_parse ();
+ prepare_percent_define_front_end_variables ();
- /* If something went wrong during the parsing, don't try to
- continue. */
- if (complaint_issued)
- return;
+ if (! complaint_issued)
+ check_and_convert_grammar ();
+
+ xfclose (gram_in);
+}
- /* Grammar has been read. Do some checking */
+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 |
+| 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"));
- /* Report any undefined symbols and consider them nonterminals. */
- symbols_check_defined ();
-
/* If the user did not define her ENDTOKEN, do it now. */
if (!endtoken)
{
endtoken->user_token_number = 0;
}
- /* Insert the initial rule, which line is that of the first rule
+ /* 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;
}
- if (! (nsyms <= SYMBOL_NUMBER_MAXIMUM && nsyms == ntokens + nvars))
- abort ();
-
- 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 is no longer needed. */
- LIST_FREE (symbol_list, grammar);
+ symbol_list_free (grammar);
}
projects / bison.git / blobdiff