/* Generate the nondeterministic finite state machine for bison,
- Copyright 1984, 1986, 1989, 2000, 2001 Free Software Foundation, Inc.
+ Copyright 1984, 1986, 1989, 2000, 2001, 2002 Free Software Foundation, Inc.
This file is part of Bison, the GNU Compiler Compiler.
The entry point is generate_states. */
#include "system.h"
+#include "bitset.h"
+#include "quotearg.h"
#include "symtab.h"
+#include "gram.h"
#include "getargs.h"
#include "reader.h"
#include "gram.h"
#include "lalr.h"
#include "reduce.h"
-int nstates;
-/* Initialize the final state to -1, otherwise, it might be set to 0
- by default, and since we don't compute the reductions of the final
- state, we end up not computing the reductions of the initial state,
- which is of course needed.
+typedef struct state_list_s
+{
+ struct state_list_s *next;
+ state_t *state;
+} state_list_t;
- FINAL_STATE is properly set by new_state when it recognizes the
- accessing symbol: EOF. */
-int final_state = -1;
-static state_t *first_state = NULL;
+static state_list_t *first_state = NULL;
+static state_list_t *last_state = NULL;
-static state_t *this_state = NULL;
-static state_t *last_state = NULL;
+static void
+state_list_append (state_t *state)
+{
+ state_list_t *node = XMALLOC (state_list_t, 1);
+ node->next = NULL;
+ node->state = state;
+
+ if (!first_state)
+ first_state = node;
+ if (last_state)
+ last_state->next = node;
+ last_state = node;
+}
static int nshifts;
-static short *shift_symbol = NULL;
+static symbol_number_t *shift_symbol = NULL;
static short *redset = NULL;
-static short *shiftset = NULL;
+static state_number_t *shiftset = NULL;
-static short **kernel_base = NULL;
+static item_number_t **kernel_base = NULL;
static int *kernel_size = NULL;
-static short *kernel_items = NULL;
-
-/* hash table for states, to recognize equivalent ones. */
-
-#define STATE_HASH_SIZE 1009
-static state_t **state_hash = NULL;
+static item_number_t *kernel_items = NULL;
\f
static void
allocate_itemsets (void)
{
- int i;
+ int i, r;
+ item_number_t *rhsp;
/* Count the number of occurrences of all the symbols in RITEMS.
Note that useless productions (hence useless nonterminals) are
int count = 0;
short *symbol_count = XCALLOC (short, nsyms + nuseless_nonterminals);
- for (i = 0; i < nritems; ++i)
- if (ritem[i] >= 0)
+ for (r = 1; r < nrules + 1; ++r)
+ for (rhsp = rules[r].rhs; *rhsp >= 0; ++rhsp)
{
count++;
- symbol_count[ritem[i]]++;
+ symbol_count[*rhsp]++;
}
/* See comments before new_itemsets. All the vectors of items
appears as an item, which is symbol_count[symbol].
We allocate that much space for each symbol. */
- kernel_base = XCALLOC (short *, nsyms);
+ kernel_base = XCALLOC (item_number_t *, nsyms);
if (count)
- kernel_items = XCALLOC (short, count);
+ kernel_items = XCALLOC (item_number_t, count);
count = 0;
for (i = 0; i < nsyms; i++)
{
allocate_itemsets ();
- shiftset = XCALLOC (short, nsyms);
+ shiftset = XCALLOC (state_number_t, nsyms);
redset = XCALLOC (short, nrules + 1);
- state_hash = XCALLOC (state_t *, STATE_HASH_SIZE);
+ state_hash_new ();
+ shift_symbol = XCALLOC (symbol_number_t, nsyms);
}
free (kernel_base);
free (kernel_size);
XFREE (kernel_items);
- free (state_hash);
+ state_hash_free ();
}
-/*----------------------------------------------------------------.
-| Find which symbols can be shifted in the current state, and for |
-| each one record which items would be active after that shift. |
-| Uses the contents of itemset. |
-| |
-| shift_symbol is set to a vector of the symbols that can be |
-| shifted. For each symbol in the grammar, kernel_base[symbol] |
-| points to a vector of item numbers activated if that symbol is |
-| shifted, and kernel_size[symbol] is their numbers. |
-`----------------------------------------------------------------*/
+/*---------------------------------------------------------------.
+| Find which symbols can be shifted in STATE, and for each one |
+| record which items would be active after that shift. Uses the |
+| contents of itemset. |
+| |
+| shift_symbol is set to a vector of the symbols that can be |
+| shifted. For each symbol in the grammar, kernel_base[symbol] |
+| points to a vector of item numbers activated if that symbol is |
+| shifted, and kernel_size[symbol] is their numbers. |
+`---------------------------------------------------------------*/
static void
-new_itemsets (void)
+new_itemsets (state_t *state)
{
int i;
if (trace_flag)
fprintf (stderr, "Entering new_itemsets, state = %d\n",
- this_state->number);
+ state->number);
for (i = 0; i < nsyms; i++)
kernel_size[i] = 0;
- shift_symbol = XCALLOC (short, nsyms);
nshifts = 0;
- for (i = 0; i < nitemset; ++i)
- {
- int symbol = ritem[itemset[i]];
- if (symbol >= 0)
- {
- if (!kernel_size[symbol])
- {
- shift_symbol[nshifts] = symbol;
- nshifts++;
- }
-
- kernel_base[symbol][kernel_size[symbol]] = itemset[i] + 1;
- kernel_size[symbol]++;
- }
- }
+ for (i = 0; i < nritemset; ++i)
+ if (ritem[itemset[i]] >= 0)
+ {
+ symbol_number_t symbol
+ = item_number_as_symbol_number (ritem[itemset[i]]);
+ if (!kernel_size[symbol])
+ {
+ shift_symbol[nshifts] = symbol;
+ nshifts++;
+ }
+
+ kernel_base[symbol][kernel_size[symbol]] = itemset[i] + 1;
+ kernel_size[symbol]++;
+ }
}
`-----------------------------------------------------------------*/
static state_t *
-new_state (int symbol)
+new_state (symbol_number_t symbol, size_t core_size, item_number_t *core)
{
- state_t *p;
+ state_t *res;
if (trace_flag)
fprintf (stderr, "Entering new_state, state = %d, symbol = %d (%s)\n",
- this_state->number, symbol, symbols[symbol]->tag);
-
- if (nstates >= MAXSHORT)
- fatal (_("too many states (max %d)"), MAXSHORT);
-
- p = STATE_ALLOC (kernel_size[symbol]);
- p->accessing_symbol = symbol;
- p->number = nstates;
- p->nitems = kernel_size[symbol];
-
- shortcpy (p->items, kernel_base[symbol], kernel_size[symbol]);
+ nstates, symbol, symbol_tag_get (symbols[symbol]));
- last_state->next = p;
- last_state = p;
- nstates++;
+ res = state_new (symbol, core_size, core);
+ state_hash_insert (res);
- /* If this is the eoftoken, then this is the final state. */
- if (symbol == 0)
- final_state = p->number;
+ /* If this is the eoftoken, and this is not the initial state, then
+ this is the final state. */
+ if (symbol == 0 && first_state)
+ final_state = res;
- return p;
+ state_list_append (res);
+ return res;
}
| equivalent one exists already. Used by append_states. |
`--------------------------------------------------------------*/
-static int
-get_state (int symbol)
+static state_number_t
+get_state (symbol_number_t symbol, size_t core_size, item_number_t *core)
{
- int key;
- int i;
state_t *sp;
if (trace_flag)
- fprintf (stderr, "Entering get_state, state = %d, symbol = %d (%s)\n",
- this_state->number, symbol, symbols[symbol]->tag);
-
- /* Add up the target state's active item numbers to get a hash key.
- */
- key = 0;
- for (i = 0; i < kernel_size[symbol]; ++i)
- key += kernel_base[symbol][i];
- key = key % STATE_HASH_SIZE;
- sp = state_hash[key];
-
- if (sp)
- {
- int found = 0;
- while (!found)
- {
- if (sp->nitems == kernel_size[symbol])
- {
- found = 1;
- for (i = 0; i < kernel_size[symbol]; ++i)
- if (kernel_base[symbol][i] != sp->items[i])
- found = 0;
- }
-
- if (!found)
- {
- if (sp->link)
- {
- sp = sp->link;
- }
- else /* bucket exhausted and no match */
- {
- sp = sp->link = new_state (symbol);
- found = 1;
- }
- }
- }
- }
- else /* bucket is empty */
- {
- state_hash[key] = sp = new_state (symbol);
- }
+ fprintf (stderr, "Entering get_state, symbol = %d (%s)\n",
+ symbol, symbol_tag_get (symbols[symbol]));
+
+ sp = state_hash_lookup (core_size, core);
+ if (!sp)
+ sp = new_state (symbol, core_size, core);
if (trace_flag)
fprintf (stderr, "Exiting get_state => %d\n", sp->number);
/*------------------------------------------------------------------.
| Use the information computed by new_itemsets to find the state |
-| numbers reached by each shift transition from the current state. |
+| numbers reached by each shift transition from STATE. |
| |
-| shiftset is set up as a vector of state numbers of those states. |
+| SHIFTSET is set up as a vector of state numbers of those states. |
`------------------------------------------------------------------*/
static void
-append_states (void)
+append_states (state_t *state)
{
int i;
int j;
- int symbol;
+ symbol_number_t symbol;
if (trace_flag)
fprintf (stderr, "Entering append_states, state = %d\n",
- this_state->number);
+ state->number);
/* first sort shift_symbol into increasing order */
}
for (i = 0; i < nshifts; i++)
- shiftset[i] = get_state (shift_symbol[i]);
+ {
+ symbol = shift_symbol[i];
+ shiftset[i] = get_state (symbol,
+ kernel_size[symbol], kernel_base[symbol]);
+ }
}
static void
new_states (void)
{
- first_state = last_state = this_state = STATE_ALLOC (0);
- nstates = 1;
+ /* The 0 at the lhs is the index of the item of this initial rule. */
+ kernel_base[0][0] = 0;
+ kernel_size[0] = 1;
+ state_list_append (new_state (0, kernel_size[0], kernel_base[0]));
}
-/*------------------------------------------------------------.
-| Save the NSHIFTS of SHIFTSET into the current linked list. |
-`------------------------------------------------------------*/
-
-static void
-save_shifts (void)
-{
- shifts *p = shifts_new (nshifts);
- shortcpy (p->shifts, shiftset, nshifts);
- this_state->shifts = p;
-}
-
/*----------------------------------------------------------------.
| Find which rules can be used for reduction transitions from the |
`----------------------------------------------------------------*/
static void
-save_reductions (void)
+save_reductions (state_t *state)
{
int count = 0;
int i;
/* If this is the final state, we want it to have no reductions at
all, although it has one for `START_SYMBOL EOF .'. */
- if (this_state->number == final_state)
+ if (final_state && state->number == final_state->number)
return;
/* Find and count the active items that represent ends of rules. */
- for (i = 0; i < nitemset; ++i)
+ for (i = 0; i < nritemset; ++i)
{
int item = ritem[itemset[i]];
if (item < 0)
}
/* Make a reductions structure and copy the data into it. */
- this_state->reductions = reductions_new (count);
- shortcpy (this_state->reductions->rules, redset, count);
+ state->reductions = reductions_new (count);
+ memcpy (state->reductions->rules, redset, count * sizeof (redset[0]));
}
\f
-/*--------------------.
+/*---------------.
| Build STATES. |
-`--------------------*/
+`---------------*/
static void
set_states (void)
{
- state_t *sp;
states = XCALLOC (state_t *, nstates);
- for (sp = first_state; sp; sp = sp->next)
+ while (first_state)
{
+ state_list_t *this = first_state;
+
/* Pessimization, but simplification of the code: make sure all
the states have a shifts, errs, and reductions, even if
reduced to 0. */
- if (!sp->shifts)
- sp->shifts = shifts_new (0);
- if (!sp->errs)
- sp->errs = errs_new (0);
- if (!sp->reductions)
- sp->reductions = reductions_new (0);
-
- states[sp->number] = sp;
+ state_t *state = this->state;
+ if (!state->shifts)
+ state_shifts_set (state, 0, 0);
+ if (!state->errs)
+ state->errs = errs_new (0);
+ if (!state->reductions)
+ state->reductions = reductions_new (0);
+
+ states[state->number] = state;
+
+ first_state = this->next;
+ free (this);
}
+ first_state = NULL;
+ last_state = NULL;
}
+
/*-------------------------------------------------------------------.
| Compute the nondeterministic finite state machine (see state.h for |
| details) from the grammar. |
void
generate_states (void)
{
+ state_list_t *list = NULL;
allocate_storage ();
new_closure (nritems);
new_states ();
+ list = first_state;
- while (this_state)
+ while (list)
{
+ state_t *state = list->state;
if (trace_flag)
fprintf (stderr, "Processing state %d (reached by %s)\n",
- this_state->number,
- symbols[this_state->accessing_symbol]->tag);
+ state->number,
+ symbol_tag_get (symbols[state->accessing_symbol]));
/* Set up ruleset and itemset for the transitions out of this
state. ruleset gets a 1 bit for each rule that could reduce
now. itemset gets a vector of all the items that could be
accepted next. */
- closure (this_state->items, this_state->nitems);
- /* record the reductions allowed out of this state */
- save_reductions ();
- /* find the itemsets of the states that shifts can reach */
- new_itemsets ();
- /* find or create the core structures for those states */
- append_states ();
-
- /* create the shifts structures for the shifts to those states,
- now that the state numbers transitioning to are known */
- save_shifts ();
-
- /* states are queued when they are created; process them all */
- this_state = this_state->next;
+ closure (state->items, state->nitems);
+ /* Record the reductions allowed out of this state. */
+ save_reductions (state);
+ /* Find the itemsets of the states that shifts can reach. */
+ new_itemsets (state);
+ /* Find or create the core structures for those states. */
+ append_states (state);
+
+ /* Create the shifts structures for the shifts to those states,
+ now that the state numbers transitioning to are known. */
+ state_shifts_set (state, nshifts, shiftset);
+
+ /* States are queued when they are created; process them all.
+ */
+ list = list->next;
}
/* discard various storage */
projects / bison.git / blobdiff