X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/2cec70b9f139dd207022c35fdbe8b49fd1cf230d..71b52b1342c65a5497f6b3780481ff2deb932a56:/src/state.c

diff --git a/src/state.c b/src/state.c
index ed4a5082..c1ac3f17 100644
--- a/src/state.c
+++ b/src/state.c
@@ -1,66 +1,466 @@
-/* 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.  |
 `---------------------------------*/
 
-#define SHIFTS_ALLOC(Nshifts)						\
-  (shifts *) xcalloc ((unsigned) (sizeof (shifts) 			\
-                                  + (Nshifts - 1) * sizeof (short)), 1)
+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;
 
-shifts *
-shifts_new (int n)
+
+/*------------------------------------------------------------------.
+| 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)
 {
-  shifts *res = SHIFTS_ALLOC (n);
-  res->nshifts = n;
+  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)
+{
+  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 a new array of N errs.  |
+| Create the states hash table.  |
 `-------------------------------*/
 
-#define ERRS_ALLOC(Nerrs)						\
-  (errs *) xcalloc ((unsigned) (sizeof (errs) 				\
-                                  + (Nerrs - 1) * sizeof (short)), 1)
+void
+state_hash_new (void)
+{
+  state_table = hash_initialize (HT_INITIAL_CAPACITY,
+                                 NULL,
+                                 state_hasher,
+                                 state_comparator,
+                                 NULL);
+}
 
 
-errs *
-errs_new (int n)
+/*---------------------------------------------.
+| Free the states hash table, not the states.  |
+`---------------------------------------------*/
+
+void
+state_hash_free (void)
 {
-  errs *res = ERRS_ALLOC (n);
-  res->nerrs = n;
-  return res;
+  hash_free (state_table);
 }
 
 
-errs *
-errs_dup (errs *src)
+/*-----------------------------------.
+| Insert S in the state hash table.  |
+`-----------------------------------*/
+
+void
+state_hash_insert (state *s)
 {
-  errs *res = errs_new (src->nerrs);
-  memcpy (res->errs, src->errs, src->nerrs);
-  return res;
+  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);
 }