/* Generate the nondeterministic finite state machine for bison,
Copyright (C) 1984, 1986, 1989 Free Software Foundation, Inc.
-This file is part of Bison, the GNU Compiler Compiler.
+ This file is part of Bison, the GNU Compiler Compiler.
-Bison 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.
+ Bison 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.
-Bison 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.
+ Bison 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. */
+ 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. */
/* See comments in state.h for the data structures that represent it.
#include "gram.h"
#include "state.h"
#include "complain.h"
-
+#include "closure.h"
extern char *nullable;
extern short *itemset;
shifts *first_shift;
reductions *first_reduction;
-extern void generate_states PARAMS((void));
-
-static int get_state PARAMS((int));
-static core *new_state PARAMS((int));
-static void allocate_itemsets PARAMS((void));
-static void allocate_storage PARAMS((void));
-static void free_storage PARAMS((void));
-static void new_itemsets PARAMS((void));
-static void append_states PARAMS((void));
-static void initialize_states PARAMS((void));
-static void save_shifts PARAMS((void));
-static void save_reductions PARAMS((void));
-static void augment_automaton PARAMS((void));
-static void insert_start_shift PARAMS((void));
-extern void initialize_closure PARAMS((int));
-extern void closure PARAMS((short *, int));
-extern void finalize_closure PARAMS((void));
+extern void generate_states PARAMS ((void));
static core *this_state;
static core *last_state;
#define STATE_TABLE_SIZE 1009
static core **state_table;
-
-
+\f
static void
allocate_itemsets (void)
{
- register short *itemp;
- register int symbol;
- register int i;
- register int count;
- register short *symbol_count;
+ short *itemp;
+ int symbol;
+ int i;
+ int count;
+ short *symbol_count;
count = 0;
- symbol_count = NEW2(nsyms, short);
+ symbol_count = NEW2 (nsyms, short);
itemp = ritem;
symbol = *itemp++;
symbol = *itemp++;
}
- /* see comments before new_itemsets. All the vectors of items
- live inside kernel_items. The number of active items after
+ /* See comments before new_itemsets. All the vectors of items
+ live inside KERNEL_ITEMS. The number of active items after
some symbol cannot be more than the number of times that symbol
appears as an item, which is symbol_count[symbol].
We allocate that much space for each symbol. */
- kernel_base = NEW2(nsyms, short *);
- kernel_items = NEW2(count, short);
+ kernel_base = NEW2 (nsyms, short *);
+ kernel_items = NEW2 (count, short);
count = 0;
for (i = 0; i < nsyms; i++)
}
shift_symbol = symbol_count;
- kernel_end = NEW2(nsyms, short *);
+ kernel_end = NEW2 (nsyms, short *);
}
static void
allocate_storage (void)
{
- allocate_itemsets();
+ allocate_itemsets ();
- shiftset = NEW2(nsyms, short);
- redset = NEW2(nrules + 1, short);
- state_table = NEW2(STATE_TABLE_SIZE, core *);
+ shiftset = NEW2 (nsyms, short);
+ redset = NEW2 (nrules + 1, short);
+ state_table = NEW2 (STATE_TABLE_SIZE, core *);
}
static void
free_storage (void)
{
- FREE(shift_symbol);
- FREE(redset);
- FREE(shiftset);
- FREE(kernel_base);
- FREE(kernel_end);
- FREE(kernel_items);
- FREE(state_table);
+ FREE (shift_symbol);
+ FREE (redset);
+ FREE (shiftset);
+ FREE (kernel_base);
+ FREE (kernel_end);
+ FREE (kernel_items);
+ FREE (state_table);
}
-/* compute the nondeterministic finite state machine (see state.h for details)
-from the grammar. */
-void
-generate_states (void)
-{
- allocate_storage();
- initialize_closure(nitems);
- initialize_states();
-
- while (this_state)
- {
- /* 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 */
- if (nshifts > 0)
- save_shifts();
-
- /* states are queued when they are created; process them all */
- this_state = this_state->next;
- }
-
- /* discard various storage */
- finalize_closure();
- free_storage();
-
- /* set up initial and final states as parser wants them */
- augment_automaton();
-}
-
+/*----------------------------------------------------------------.
+| 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_end[symbol] points after the end of that |
+| vector. |
+`----------------------------------------------------------------*/
-/* 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_end[symbol] points after the end of that vector. */
static void
new_itemsets (void)
{
- register int i;
- register int shiftcount;
- register short *isp;
- register short *ksp;
- register int symbol;
-
-#ifdef TRACE
- fprintf(stderr, "Entering new_itemsets\n");
+ int i;
+ int shiftcount;
+ short *isp;
+ short *ksp;
+ int symbol;
+
+#if TRACE
+ fprintf (stderr, "Entering new_itemsets\n");
#endif
for (i = 0; i < nsyms; i++)
symbol = ritem[i];
if (symbol > 0)
{
- ksp = kernel_end[symbol];
+ ksp = kernel_end[symbol];
- if (!ksp)
+ if (!ksp)
{
shift_symbol[shiftcount++] = symbol;
ksp = kernel_base[symbol];
}
- *ksp++ = i + 1;
- kernel_end[symbol] = ksp;
+ *ksp++ = i + 1;
+ kernel_end[symbol] = ksp;
}
}
-/* Use the information computed by new_itemsets to find the state numbers
- reached by each shift transition from the current state.
+/*-----------------------------------------------------------------.
+| Subroutine of get_state. Create a new state for those items, if |
+| necessary. |
+`-----------------------------------------------------------------*/
- shiftset is set up as a vector of state numbers of those states. */
-static void
-append_states (void)
+static core *
+new_state (int symbol)
{
- register int i;
- register int j;
- register int symbol;
+ int n;
+ core *p;
+ short *isp1;
+ short *isp2;
+ short *iend;
-#ifdef TRACE
- fprintf(stderr, "Entering append_states\n");
+#if TRACE
+ fprintf (stderr, "Entering new_state, symbol = %d\n", symbol);
#endif
- /* first sort shift_symbol into increasing order */
+ if (nstates >= MAXSHORT)
+ fatal (_("too many states (max %d)"), MAXSHORT);
- for (i = 1; i < nshifts; i++)
- {
- symbol = shift_symbol[i];
- j = i;
- while (j > 0 && shift_symbol[j - 1] > symbol)
- {
- shift_symbol[j] = shift_symbol[j - 1];
- j--;
- }
- shift_symbol[j] = symbol;
- }
+ isp1 = kernel_base[symbol];
+ iend = kernel_end[symbol];
+ n = iend - isp1;
- for (i = 0; i < nshifts; i++)
- {
- symbol = shift_symbol[i];
- shiftset[i] = get_state(symbol);
- }
-}
+ p =
+ (core *) xmalloc ((unsigned) (sizeof (core) + (n - 1) * sizeof (short)));
+ p->accessing_symbol = symbol;
+ p->number = nstates;
+ p->nitems = n;
+
+ isp2 = p->items;
+ while (isp1 < iend)
+ *isp2++ = *isp1++;
+
+ last_state->next = p;
+ last_state = p;
+ nstates++;
+ return p;
+}
-/* find the state number for the state we would get to
-(from the current state) by shifting symbol.
-Create a new state if no equivalent one exists already.
-Used by append_states */
+
+/*--------------------------------------------------------------.
+| Find the state number for the state we would get to (from the |
+| current state) by shifting symbol. Create a new state if no |
+| equivalent one exists already. Used by append_states. |
+`--------------------------------------------------------------*/
static int
get_state (int symbol)
{
- register int key;
- register short *isp1;
- register short *isp2;
- register short *iend;
- register core *sp;
- register int found;
+ int key;
+ short *isp1;
+ short *isp2;
+ short *iend;
+ core *sp;
+ int found;
int n;
-#ifdef TRACE
- fprintf(stderr, "Entering get_state, symbol = %d\n", symbol);
+#if TRACE
+ fprintf (stderr, "Entering get_state, symbol = %d\n", symbol);
#endif
isp1 = kernel_base[symbol];
{
sp = sp->link;
}
- else /* bucket exhausted and no match */
+ else /* bucket exhausted and no match */
{
- sp = sp->link = new_state(symbol);
+ sp = sp->link = new_state (symbol);
found = 1;
}
}
}
}
- else /* bucket is empty */
+ else /* bucket is empty */
{
- state_table[key] = sp = new_state(symbol);
+ state_table[key] = sp = new_state (symbol);
}
return sp->number;
}
+/*------------------------------------------------------------------.
+| Use the information computed by new_itemsets to find the state |
+| numbers reached by each shift transition from the current state. |
+| |
+| shiftset is set up as a vector of state numbers of those states. |
+`------------------------------------------------------------------*/
-
-/* subroutine of get_state. create a new state for those items, if necessary. */
-
-static core *
-new_state (int symbol)
+static void
+append_states (void)
{
- register int n;
- register core *p;
- register short *isp1;
- register short *isp2;
- register short *iend;
-
-#ifdef TRACE
- fprintf(stderr, "Entering new_state, symbol = %d\n", symbol);
-#endif
-
- if (nstates >= MAXSHORT)
- fatal (_("too many states (max %d)"), MAXSHORT);
+ int i;
+ int j;
+ int symbol;
- isp1 = kernel_base[symbol];
- iend = kernel_end[symbol];
- n = iend - isp1;
-
- p = (core *) xmalloc((unsigned) (sizeof(core) + (n - 1) * sizeof(short)));
- p->accessing_symbol = symbol;
- p->number = nstates;
- p->nitems = n;
-
- isp2 = p->items;
- while (isp1 < iend)
- *isp2++ = *isp1++;
+#if TRACE
+ fprintf (stderr, "Entering append_states\n");
+#endif
- last_state->next = p;
- last_state = p;
+ /* first sort shift_symbol into increasing order */
- nstates++;
+ for (i = 1; i < nshifts; i++)
+ {
+ symbol = shift_symbol[i];
+ j = i;
+ while (j > 0 && shift_symbol[j - 1] > symbol)
+ {
+ shift_symbol[j] = shift_symbol[j - 1];
+ j--;
+ }
+ shift_symbol[j] = symbol;
+ }
- return p;
+ for (i = 0; i < nshifts; i++)
+ {
+ symbol = shift_symbol[i];
+ shiftset[i] = get_state (symbol);
+ }
}
static void
-initialize_states (void)
+new_states (void)
{
- register core *p;
-/* register unsigned *rp1; JF unused */
-/* register unsigned *rp2; JF unused */
-/* register unsigned *rend; JF unused */
+ core *p;
- p = (core *) xmalloc((unsigned) (sizeof(core) - sizeof(short)));
+ p = (core *) xmalloc ((unsigned) (sizeof (core) - sizeof (short)));
first_state = last_state = this_state = p;
nstates = 1;
}
static void
save_shifts (void)
{
- register shifts *p;
- register short *sp1;
- register short *sp2;
- register short *send;
+ shifts *p;
+ short *sp1;
+ short *sp2;
+ short *send;
- p = (shifts *) xmalloc((unsigned) (sizeof(shifts) +
- (nshifts - 1) * sizeof(short)));
+ p = (shifts *) xmalloc ((unsigned) (sizeof (shifts) +
+ (nshifts - 1) * sizeof (short)));
p->number = this_state->number;
p->nshifts = nshifts;
}
+/*------------------------------------------------------------------.
+| Subroutine of augment_automaton. Create the next-to-final state, |
+| to which a shift has already been made in the initial state. |
+`------------------------------------------------------------------*/
-/* find which rules can be used for reduction transitions from the current state
- and make a reductions structure for the state to record their rule numbers. */
static void
-save_reductions (void)
+insert_start_shift (void)
{
- register short *isp;
- register short *rp1;
- register short *rp2;
- register int item;
- register int count;
- register reductions *p;
-
- short *rend;
-
- /* find and count the active items that represent ends of rules */
-
- count = 0;
- for (isp = itemset; isp < itemsetend; isp++)
- {
- item = ritem[*isp];
- if (item < 0)
- {
- redset[count++] = -item;
- }
- }
-
- /* make a reductions structure and copy the data into it. */
+ core *statep;
+ shifts *sp;
- if (count)
- {
- p = (reductions *) xmalloc((unsigned) (sizeof(reductions) +
- (count - 1) * sizeof(short)));
-
- p->number = this_state->number;
- p->nreds = count;
+ statep = (core *) xmalloc ((unsigned) (sizeof (core) - sizeof (short)));
+ statep->number = nstates;
+ statep->accessing_symbol = start_symbol;
- rp1 = redset;
- rp2 = p->rules;
- rend = rp1 + count;
+ last_state->next = statep;
+ last_state = statep;
- while (rp1 < rend)
- *rp2++ = *rp1++;
+ /* Make a shift from this state to (what will be) the final state. */
+ sp = NEW (shifts);
+ sp->number = nstates++;
+ sp->nshifts = 1;
+ sp->shifts[0] = nstates;
- if (last_reduction)
- {
- last_reduction->next = p;
- last_reduction = p;
- }
- else
- {
- first_reduction = p;
- last_reduction = p;
- }
- }
+ last_shift->next = sp;
+ last_shift = sp;
}
+/*------------------------------------------------------------------.
+| Make sure that the initial state has a shift that accepts the |
+| grammar's start symbol and goes to the next-to-final state, which |
+| has a shift going to the final state, which has a shift to the |
+| termination state. Create such states and shifts if they don't |
+| happen to exist already. |
+`------------------------------------------------------------------*/
-/* Make sure that the initial state has a shift that accepts the
-grammar's start symbol and goes to the next-to-final state,
-which has a shift going to the final state, which has a shift
-to the termination state.
-Create such states and shifts if they don't happen to exist already. */
static void
augment_automaton (void)
{
- register int i;
- register int k;
-/* register int found; JF unused */
- register core *statep;
- register shifts *sp;
- register shifts *sp2;
- register shifts *sp1 = NULL;
+ int i;
+ int k;
+ core *statep;
+ shifts *sp;
+ shifts *sp2;
+ shifts *sp1 = NULL;
sp = first_shift;
/* The states reached by shifts from first_state are numbered 1...K.
Look for one reached by start_symbol. */
while (statep->accessing_symbol < start_symbol
- && statep->number < k)
+ && statep->number < k)
statep = statep->next;
if (statep->accessing_symbol == start_symbol)
{
/* We already have a next-to-final state.
- Make sure it has a shift to what will be the final state. */
+ Make sure it has a shift to what will be the final state. */
k = statep->number;
while (sp && sp->number < k)
if (sp && sp->number == k)
{
- sp2 = (shifts *) xmalloc((unsigned) (sizeof(shifts)
- + sp->nshifts * sizeof(short)));
+ sp2 = (shifts *) xmalloc ((unsigned) (sizeof (shifts)
+ +
+ sp->nshifts *
+ sizeof (short)));
sp2->number = k;
sp2->nshifts = sp->nshifts + 1;
sp2->shifts[0] = nstates;
sp1->next = sp2;
if (sp == last_shift)
last_shift = sp2;
- FREE(sp);
+ FREE (sp);
}
else
{
- sp2 = NEW(shifts);
+ sp2 = NEW (shifts);
sp2->number = k;
sp2->nshifts = 1;
sp2->shifts[0] = nstates;
{
/* There is no next-to-final state as yet. */
/* Add one more shift in first_shift,
- going to the next-to-final state (yet to be made). */
+ going to the next-to-final state (yet to be made). */
sp = first_shift;
- sp2 = (shifts *) xmalloc(sizeof(shifts)
- + sp->nshifts * sizeof(short));
+ sp2 = (shifts *) xmalloc (sizeof (shifts)
+ + sp->nshifts * sizeof (short));
sp2->nshifts = sp->nshifts + 1;
/* Stick this shift into the vector at the proper place. */
sp2->shifts[k++] = nstates;
/* Patch sp2 into the chain of shifts
- in place of sp, at the beginning. */
+ in place of sp, at the beginning. */
sp2->next = sp->next;
first_shift = sp2;
if (last_shift == sp)
last_shift = sp2;
- FREE(sp);
+ FREE (sp);
/* Create the next-to-final state, with shift to
- what will be the final state. */
- insert_start_shift();
+ what will be the final state. */
+ insert_start_shift ();
}
}
else
{
/* The initial state didn't even have any shifts.
Give it one shift, to the next-to-final state. */
- sp = NEW(shifts);
+ sp = NEW (shifts);
sp->nshifts = 1;
sp->shifts[0] = nstates;
/* Create the next-to-final state, with shift to
what will be the final state. */
- insert_start_shift();
+ insert_start_shift ();
}
}
else
{
/* There are no shifts for any state.
- Make one shift, from the initial state to the next-to-final state. */
+ Make one shift, from the initial state to the next-to-final state. */
- sp = NEW(shifts);
+ sp = NEW (shifts);
sp->nshifts = 1;
sp->shifts[0] = nstates;
last_shift = sp;
/* Create the next-to-final state, with shift to
- what will be the final state. */
- insert_start_shift();
+ what will be the final state. */
+ insert_start_shift ();
}
/* Make the final state--the one that follows a shift from the
next-to-final state.
The symbol for that shift is 0 (end-of-file). */
- statep = (core *) xmalloc((unsigned) (sizeof(core) - sizeof(short)));
+ statep = (core *) xmalloc ((unsigned) (sizeof (core) - sizeof (short)));
statep->number = nstates;
last_state->next = statep;
last_state = statep;
/* Make the shift from the final state to the termination state. */
- sp = NEW(shifts);
+ sp = NEW (shifts);
sp->number = nstates++;
sp->nshifts = 1;
sp->shifts[0] = nstates;
final_state = nstates;
/* Make the termination state. */
- statep = (core *) xmalloc((unsigned) (sizeof(core) - sizeof(short)));
+ statep = (core *) xmalloc ((unsigned) (sizeof (core) - sizeof (short)));
statep->number = nstates++;
last_state->next = statep;
last_state = statep;
}
-/* subroutine of augment_automaton.
- Create the next-to-final state, to which a shift has already been made in
- the initial state. */
+/*----------------------------------------------------------------.
+| Find which rules can be used for reduction transitions from the |
+| current state and make a reductions structure for the state to |
+| record their rule numbers. |
+`----------------------------------------------------------------*/
+
static void
-insert_start_shift (void)
+save_reductions (void)
{
- register core *statep;
- register shifts *sp;
+ short *isp;
+ short *rp1;
+ short *rp2;
+ int item;
+ int count;
+ reductions *p;
- statep = (core *) xmalloc((unsigned) (sizeof(core) - sizeof(short)));
- statep->number = nstates;
- statep->accessing_symbol = start_symbol;
+ short *rend;
- last_state->next = statep;
- last_state = statep;
+ /* Find and count the active items that represent ends of rules. */
- /* Make a shift from this state to (what will be) the final state. */
- sp = NEW(shifts);
- sp->number = nstates++;
- sp->nshifts = 1;
- sp->shifts[0] = nstates;
+ count = 0;
+ for (isp = itemset; isp < itemsetend; isp++)
+ {
+ item = ritem[*isp];
+ if (item < 0)
+ redset[count++] = -item;
+ }
- last_shift->next = sp;
- last_shift = sp;
+ /* Make a reductions structure and copy the data into it. */
+
+ if (count)
+ {
+ p = (reductions *) xmalloc ((unsigned) (sizeof (reductions) +
+ (count - 1) * sizeof (short)));
+
+ p->number = this_state->number;
+ p->nreds = count;
+
+ rp1 = redset;
+ rp2 = p->rules;
+ rend = rp1 + count;
+
+ for (/* nothing */; rp1 < rend; ++rp1, ++rp2)
+ *rp2 = *rp1;
+
+ if (last_reduction)
+ {
+ last_reduction->next = p;
+ last_reduction = p;
+ }
+ else
+ {
+ first_reduction = p;
+ last_reduction = p;
+ }
+ }
+}
+
+\f
+/*-------------------------------------------------------------------.
+| Compute the nondeterministic finite state machine (see state.h for |
+| details) from the grammar. |
+`-------------------------------------------------------------------*/
+
+void
+generate_states (void)
+{
+ allocate_storage ();
+ new_closure (nitems);
+ new_states ();
+
+ while (this_state)
+ {
+ /* 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 */
+ if (nshifts > 0)
+ save_shifts ();
+
+ /* states are queued when they are created; process them all */
+ this_state = this_state->next;
+ }
+
+ /* discard various storage */
+ free_closure ();
+ free_storage ();
+
+ /* set up initial and final states as parser wants them */
+ augment_automaton ();
}
projects / bison.git / blobdiff