-/* Type definitions for nondeterministic finite state machine for bison,
- Copyright 2001 Free Software Foundation, Inc.
+/* Type definitions for the finite state machine for Bison.
+
+ Copyright (C) 2001-2007, 2009-2012 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 <hash.h>
+
+#include "complain.h"
+#include "gram.h"
#include "state.h"
+#include "print-xml.h"
+
+
+ /*-------------------.
+ | Shifts and Gotos. |
+ `-------------------*/
+
+
+/*-----------------------------------------.
+| Create a new array of NUM shifts/gotos. |
+`-----------------------------------------*/
+
+static transitions *
+transitions_new (int num, state **the_states)
+{
+ size_t states_size = num * sizeof *the_states;
+ transitions *res = xmalloc (offsetof (transitions, states) + states_size);
+ res->num = num;
+ memcpy (res->states, the_states, states_size);
+ return res;
+}
+
+
+/*-------------------------------------------------------.
+| Return the state such that SHIFTS contain a shift/goto |
+| to it on SYM. Abort if none found. |
+`-------------------------------------------------------*/
+
+state *
+transitions_to (transitions *shifts, symbol_number sym)
+{
+ int j;
+ for (j = 0; ; j++)
+ {
+ aver (j < shifts->num);
+ if (TRANSITION_SYMBOL (shifts, j) == sym)
+ return shifts->states[j];
+ }
+}
+
+
+ /*--------------------.
+ | Error transitions. |
+ `--------------------*/
+
/*---------------------------------.
-| Create a new array of N shitfs. |
+| Create a new array of NUM errs. |
`---------------------------------*/
-shifts *
-shifts_new (int n)
+errs *
+errs_new (int num, symbol **tokens)
+{
+ size_t symbols_size = num * sizeof *tokens;
+ errs *res = xmalloc (offsetof (errs, symbols) + symbols_size);
+ res->num = num;
+ memcpy (res->symbols, tokens, symbols_size);
+ return res;
+}
+
+
+
+
+ /*-------------.
+ | Reductions. |
+ `-------------*/
+
+
+/*---------------------------------------.
+| Create a new array of NUM reductions. |
+`---------------------------------------*/
+
+static reductions *
+reductions_new (int num, rule **reds)
+{
+ size_t rules_size = num * sizeof *reds;
+ reductions *res = xmalloc (offsetof (reductions, rules) + rules_size);
+ res->num = num;
+ res->lookahead_tokens = NULL;
+ memcpy (res->rules, reds, rules_size);
+ return res;
+}
+
+
+
+ /*---------.
+ | States. |
+ `---------*/
+
+
+state_number nstates = 0;
+/* FINAL_STATE is properly set by new_state when it recognizes its
+ accessing symbol: $end. */
+state *final_state = NULL;
+
+
+/*------------------------------------------------------------------.
+| Create a new state with ACCESSING_SYMBOL, for those items. Store |
+| it in the state hash table. |
+`------------------------------------------------------------------*/
+
+state *
+state_new (symbol_number accessing_symbol,
+ size_t nitems, item_number *core)
+{
+ state *res;
+ size_t items_size = nitems * sizeof *core;
+
+ aver (nstates < STATE_NUMBER_MAXIMUM);
+
+ res = xmalloc (offsetof (state, items) + items_size);
+ res->number = nstates++;
+ res->accessing_symbol = accessing_symbol;
+ res->transitions = NULL;
+ res->reductions = NULL;
+ res->errs = NULL;
+ res->state_list = NULL;
+ res->consistent = 0;
+ res->solved_conflicts = NULL;
+ res->solved_conflicts_xml = NULL;
+
+ res->nitems = nitems;
+ memcpy (res->items, core, items_size);
+
+ state_hash_insert (res);
+
+ return res;
+}
+
+state *
+state_new_isocore (state const *s)
{
- shifts *res = SHIFTS_ALLOC (n);
- res->nshifts = n;
+ state *res;
+ size_t items_size = s->nitems * sizeof *s->items;
+
+ aver (nstates < STATE_NUMBER_MAXIMUM);
+
+ res = xmalloc (offsetof (state, items) + items_size);
+ res->number = nstates++;
+ res->accessing_symbol = s->accessing_symbol;
+ res->transitions =
+ transitions_new (s->transitions->num, s->transitions->states);
+ res->reductions = reductions_new (s->reductions->num, s->reductions->rules);
+ res->errs = NULL;
+ res->state_list = NULL;
+ res->consistent = s->consistent;
+ res->solved_conflicts = NULL;
+ res->solved_conflicts_xml = NULL;
+
+ res->nitems = s->nitems;
+ memcpy (res->items, s->items, items_size);
+
return res;
}
+
+
+/*---------.
+| Free S. |
+`---------*/
+
+static void
+state_free (state *s)
+{
+ free (s->transitions);
+ free (s->reductions);
+ free (s->errs);
+ free (s);
+}
+
+
+/*---------------------------.
+| Set the transitions of S. |
+`---------------------------*/
+
+void
+state_transitions_set (state *s, int num, state **trans)
+{
+ aver (!s->transitions);
+ s->transitions = transitions_new (num, trans);
+}
+
+
+/*--------------------------.
+| Set the reductions of S. |
+`--------------------------*/
+
+void
+state_reductions_set (state *s, int num, rule **reds)
+{
+ aver (!s->reductions);
+ s->reductions = reductions_new (num, reds);
+}
+
+
+int
+state_reduction_find (state *s, rule *r)
+{
+ int i;
+ reductions *reds = s->reductions;
+ for (i = 0; i < reds->num; ++i)
+ if (reds->rules[i] == r)
+ return i;
+ return -1;
+}
+
+
+/*--------------------.
+| Set the errs of S. |
+`--------------------*/
+
+void
+state_errs_set (state *s, int num, symbol **tokens)
+{
+ aver (!s->errs);
+ s->errs = errs_new (num, tokens);
+}
+
+
+
+/*--------------------------------------------------.
+| Print on OUT all the lookahead tokens such that S |
+| wants to reduce R. |
+`--------------------------------------------------*/
+
+void
+state_rule_lookahead_tokens_print (state *s, rule *r, FILE *out)
+{
+ /* Find the reduction we are handling. */
+ reductions *reds = s->reductions;
+ int red = state_reduction_find (s, r);
+
+ /* Print them if there are. */
+ if (reds->lookahead_tokens && red != -1)
+ {
+ bitset_iterator biter;
+ int k;
+ char const *sep = "";
+ fprintf (out, " [");
+ BITSET_FOR_EACH (biter, reds->lookahead_tokens[red], k, 0)
+ {
+ fprintf (out, "%s%s", sep, symbols[k]->tag);
+ sep = ", ";
+ }
+ fprintf (out, "]");
+ }
+}
+
+void
+state_rule_lookahead_tokens_print_xml (state *s, rule *r,
+ FILE *out, int level)
+{
+ /* Find the reduction we are handling. */
+ reductions *reds = s->reductions;
+ int red = state_reduction_find (s, r);
+
+ /* Print them if there are. */
+ if (reds->lookahead_tokens && red != -1)
+ {
+ bitset_iterator biter;
+ int k;
+ xml_puts (out, level, "<lookaheads>");
+ BITSET_FOR_EACH (biter, reds->lookahead_tokens[red], k, 0)
+ {
+ xml_printf (out, level + 1, "<symbol>%s</symbol>",
+ xml_escape (symbols[k]->tag));
+ }
+ xml_puts (out, level, "</lookaheads>");
+ }
+}
+
+
+/*---------------------.
+| A state hash table. |
+`---------------------*/
+
+/* Initial capacity of states hash table. */
+#define HT_INITIAL_CAPACITY 257
+
+static struct hash_table *state_table = NULL;
+
+/* Two states are equal if they have the same core items. */
+static inline bool
+state_compare (state const *s1, state const *s2)
+{
+ size_t i;
+
+ if (s1->nitems != s2->nitems)
+ return false;
+
+ for (i = 0; i < s1->nitems; ++i)
+ if (s1->items[i] != s2->items[i])
+ return false;
+
+ return true;
+}
+
+static bool
+state_comparator (void const *s1, void const *s2)
+{
+ return state_compare (s1, s2);
+}
+
+static inline size_t
+state_hash (state const *s, size_t tablesize)
+{
+ /* Add up the state's item numbers to get a hash key. */
+ size_t key = 0;
+ size_t i;
+ for (i = 0; i < s->nitems; ++i)
+ key += s->items[i];
+ return key % tablesize;
+}
+
+static size_t
+state_hasher (void const *s, size_t tablesize)
+{
+ return state_hash (s, tablesize);
+}
+
+
+/*-------------------------------.
+| Create the states hash table. |
+`-------------------------------*/
+
+void
+state_hash_new (void)
+{
+ state_table = hash_initialize (HT_INITIAL_CAPACITY,
+ NULL,
+ state_hasher,
+ state_comparator,
+ NULL);
+}
+
+
+/*---------------------------------------------.
+| Free the states hash table, not the states. |
+`---------------------------------------------*/
+
+void
+state_hash_free (void)
+{
+ hash_free (state_table);
+}
+
+
+/*-----------------------------------.
+| Insert S in the state hash table. |
+`-----------------------------------*/
+
+void
+state_hash_insert (state *s)
+{
+ if (!hash_insert (state_table, s))
+ xalloc_die ();
+}
+
+
+/*------------------------------------------------------------------.
+| Find the state associated to the CORE, and return it. If it does |
+| not exist yet, return NULL. |
+`------------------------------------------------------------------*/
+
+state *
+state_hash_lookup (size_t nitems, item_number *core)
+{
+ size_t items_size = nitems * sizeof *core;
+ state *probe = xmalloc (offsetof (state, items) + items_size);
+ state *entry;
+
+ probe->nitems = nitems;
+ memcpy (probe->items, core, items_size);
+ entry = hash_lookup (state_table, probe);
+ free (probe);
+ return entry;
+}
+
+
+/*--------------------------------------------------------.
+| Record S and all states reachable from S in REACHABLE. |
+`--------------------------------------------------------*/
+
+static void
+state_record_reachable_states (state *s, bitset reachable)
+{
+ if (bitset_test (reachable, s->number))
+ return;
+ bitset_set (reachable, s->number);
+ {
+ int i;
+ for (i = 0; i < s->transitions->num; ++i)
+ if (!TRANSITION_IS_DISABLED (s->transitions, i))
+ state_record_reachable_states (s->transitions->states[i], reachable);
+ }
+}
+
+void
+state_remove_unreachable_states (state_number old_to_new[])
+{
+ state_number nstates_reachable = 0;
+ bitset reachable = bitset_create (nstates, BITSET_FIXED);
+ state_record_reachable_states (states[0], reachable);
+ {
+ state_number i;
+ for (i = 0; i < nstates; ++i)
+ {
+ if (bitset_test (reachable, states[i]->number))
+ {
+ states[nstates_reachable] = states[i];
+ states[nstates_reachable]->number = nstates_reachable;
+ old_to_new[i] = nstates_reachable++;
+ }
+ else
+ {
+ state_free (states[i]);
+ old_to_new[i] = nstates;
+ }
+ }
+ }
+ nstates = nstates_reachable;
+ bitset_free (reachable);
+}
+
+/* All the decorated states, indexed by the state number. */
+state **states = NULL;
+
+
+/*----------------------.
+| Free all the states. |
+`----------------------*/
+
+void
+states_free (void)
+{
+ state_number i;
+ for (i = 0; i < nstates; ++i)
+ state_free (states[i]);
+ free (states);
+}
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