mirror of
https://git.hardenedbsd.org/hardenedbsd/HardenedBSD.git
synced 2024-12-21 08:24:10 +01:00
9f36c7f497
In case you're wondering, the gcc-2.7.2.1 import uses this to generate code. The size of the generated code is bigger than the entire bison release, making this a saving. The bison doc is pretty good apparently.
705 lines
15 KiB
C
705 lines
15 KiB
C
/* 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.
|
|
|
|
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.
|
|
|
|
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, 675 Mass Ave, Cambridge, MA 02139, USA. */
|
|
|
|
|
|
/* See comments in state.h for the data structures that represent it.
|
|
The entry point is generate_states. */
|
|
|
|
#include <stdio.h>
|
|
#include "system.h"
|
|
#include "machine.h"
|
|
#include "new.h"
|
|
#include "gram.h"
|
|
#include "state.h"
|
|
|
|
|
|
extern char *nullable;
|
|
extern short *itemset;
|
|
extern short *itemsetend;
|
|
|
|
|
|
int nstates;
|
|
int final_state;
|
|
core *first_state;
|
|
shifts *first_shift;
|
|
reductions *first_reduction;
|
|
|
|
int get_state();
|
|
core *new_state();
|
|
|
|
void new_itemsets();
|
|
void append_states();
|
|
void initialize_states();
|
|
void save_shifts();
|
|
void save_reductions();
|
|
void augment_automaton();
|
|
void insert_start_shift();
|
|
extern void initialize_closure();
|
|
extern void closure();
|
|
extern void finalize_closure();
|
|
extern void toomany();
|
|
|
|
static core *this_state;
|
|
static core *last_state;
|
|
static shifts *last_shift;
|
|
static reductions *last_reduction;
|
|
|
|
static int nshifts;
|
|
static short *shift_symbol;
|
|
|
|
static short *redset;
|
|
static short *shiftset;
|
|
|
|
static short **kernel_base;
|
|
static short **kernel_end;
|
|
static short *kernel_items;
|
|
|
|
/* hash table for states, to recognize equivalent ones. */
|
|
|
|
#define STATE_TABLE_SIZE 1009
|
|
static core **state_table;
|
|
|
|
|
|
|
|
void
|
|
allocate_itemsets()
|
|
{
|
|
register short *itemp;
|
|
register int symbol;
|
|
register int i;
|
|
register int count;
|
|
register short *symbol_count;
|
|
|
|
count = 0;
|
|
symbol_count = NEW2(nsyms, short);
|
|
|
|
itemp = ritem;
|
|
symbol = *itemp++;
|
|
while (symbol)
|
|
{
|
|
if (symbol > 0)
|
|
{
|
|
count++;
|
|
symbol_count[symbol]++;
|
|
}
|
|
symbol = *itemp++;
|
|
}
|
|
|
|
/* 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);
|
|
|
|
count = 0;
|
|
for (i = 0; i < nsyms; i++)
|
|
{
|
|
kernel_base[i] = kernel_items + count;
|
|
count += symbol_count[i];
|
|
}
|
|
|
|
shift_symbol = symbol_count;
|
|
kernel_end = NEW2(nsyms, short *);
|
|
}
|
|
|
|
|
|
void
|
|
allocate_storage()
|
|
{
|
|
allocate_itemsets();
|
|
|
|
shiftset = NEW2(nsyms, short);
|
|
redset = NEW2(nrules + 1, short);
|
|
state_table = NEW2(STATE_TABLE_SIZE, core *);
|
|
}
|
|
|
|
|
|
void
|
|
free_storage()
|
|
{
|
|
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()
|
|
{
|
|
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. */
|
|
void
|
|
new_itemsets()
|
|
{
|
|
register int i;
|
|
register int shiftcount;
|
|
register short *isp;
|
|
register short *ksp;
|
|
register int symbol;
|
|
|
|
#ifdef TRACE
|
|
fprintf(stderr, "Entering new_itemsets\n");
|
|
#endif
|
|
|
|
for (i = 0; i < nsyms; i++)
|
|
kernel_end[i] = NULL;
|
|
|
|
shiftcount = 0;
|
|
|
|
isp = itemset;
|
|
|
|
while (isp < itemsetend)
|
|
{
|
|
i = *isp++;
|
|
symbol = ritem[i];
|
|
if (symbol > 0)
|
|
{
|
|
ksp = kernel_end[symbol];
|
|
|
|
if (!ksp)
|
|
{
|
|
shift_symbol[shiftcount++] = symbol;
|
|
ksp = kernel_base[symbol];
|
|
}
|
|
|
|
*ksp++ = i + 1;
|
|
kernel_end[symbol] = ksp;
|
|
}
|
|
}
|
|
|
|
nshifts = shiftcount;
|
|
}
|
|
|
|
|
|
|
|
/* 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. */
|
|
void
|
|
append_states()
|
|
{
|
|
register int i;
|
|
register int j;
|
|
register int symbol;
|
|
|
|
#ifdef TRACE
|
|
fprintf(stderr, "Entering append_states\n");
|
|
#endif
|
|
|
|
/* first sort shift_symbol into increasing order */
|
|
|
|
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;
|
|
}
|
|
|
|
for (i = 0; i < nshifts; i++)
|
|
{
|
|
symbol = shift_symbol[i];
|
|
shiftset[i] = get_state(symbol);
|
|
}
|
|
}
|
|
|
|
|
|
|
|
/* 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 */
|
|
|
|
int
|
|
get_state(symbol)
|
|
int symbol;
|
|
{
|
|
register int key;
|
|
register short *isp1;
|
|
register short *isp2;
|
|
register short *iend;
|
|
register core *sp;
|
|
register int found;
|
|
|
|
int n;
|
|
|
|
#ifdef TRACE
|
|
fprintf(stderr, "Entering get_state, symbol = %d\n", symbol);
|
|
#endif
|
|
|
|
isp1 = kernel_base[symbol];
|
|
iend = kernel_end[symbol];
|
|
n = iend - isp1;
|
|
|
|
/* add up the target state's active item numbers to get a hash key */
|
|
key = 0;
|
|
while (isp1 < iend)
|
|
key += *isp1++;
|
|
|
|
key = key % STATE_TABLE_SIZE;
|
|
|
|
sp = state_table[key];
|
|
|
|
if (sp)
|
|
{
|
|
found = 0;
|
|
while (!found)
|
|
{
|
|
if (sp->nitems == n)
|
|
{
|
|
found = 1;
|
|
isp1 = kernel_base[symbol];
|
|
isp2 = sp->items;
|
|
|
|
while (found && isp1 < iend)
|
|
{
|
|
if (*isp1++ != *isp2++)
|
|
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_table[key] = sp = new_state(symbol);
|
|
}
|
|
|
|
return (sp->number);
|
|
}
|
|
|
|
|
|
|
|
/* subroutine of get_state. create a new state for those items, if necessary. */
|
|
|
|
core *
|
|
new_state(symbol)
|
|
int symbol;
|
|
{
|
|
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)
|
|
toomany("states");
|
|
|
|
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++;
|
|
|
|
last_state->next = p;
|
|
last_state = p;
|
|
|
|
nstates++;
|
|
|
|
return (p);
|
|
}
|
|
|
|
|
|
void
|
|
initialize_states()
|
|
{
|
|
register core *p;
|
|
/* register unsigned *rp1; JF unused */
|
|
/* register unsigned *rp2; JF unused */
|
|
/* register unsigned *rend; JF unused */
|
|
|
|
p = (core *) xmalloc((unsigned) (sizeof(core) - sizeof(short)));
|
|
first_state = last_state = this_state = p;
|
|
nstates = 1;
|
|
}
|
|
|
|
|
|
void
|
|
save_shifts()
|
|
{
|
|
register shifts *p;
|
|
register short *sp1;
|
|
register short *sp2;
|
|
register short *send;
|
|
|
|
p = (shifts *) xmalloc((unsigned) (sizeof(shifts) +
|
|
(nshifts - 1) * sizeof(short)));
|
|
|
|
p->number = this_state->number;
|
|
p->nshifts = nshifts;
|
|
|
|
sp1 = shiftset;
|
|
sp2 = p->shifts;
|
|
send = shiftset + nshifts;
|
|
|
|
while (sp1 < send)
|
|
*sp2++ = *sp1++;
|
|
|
|
if (last_shift)
|
|
{
|
|
last_shift->next = p;
|
|
last_shift = p;
|
|
}
|
|
else
|
|
{
|
|
first_shift = p;
|
|
last_shift = p;
|
|
}
|
|
}
|
|
|
|
|
|
|
|
/* 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. */
|
|
void
|
|
save_reductions()
|
|
{
|
|
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. */
|
|
|
|
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;
|
|
|
|
while (rp1 < rend)
|
|
*rp2++ = *rp1++;
|
|
|
|
if (last_reduction)
|
|
{
|
|
last_reduction->next = p;
|
|
last_reduction = p;
|
|
}
|
|
else
|
|
{
|
|
first_reduction = p;
|
|
last_reduction = p;
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
|
|
/* 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. */
|
|
void
|
|
augment_automaton()
|
|
{
|
|
register int i;
|
|
register int k;
|
|
/* register int found; JF unused */
|
|
register core *statep;
|
|
register shifts *sp;
|
|
register shifts *sp2;
|
|
register shifts *sp1;
|
|
|
|
sp = first_shift;
|
|
|
|
if (sp)
|
|
{
|
|
if (sp->number == 0)
|
|
{
|
|
k = sp->nshifts;
|
|
statep = first_state->next;
|
|
|
|
/* 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 = 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. */
|
|
k = statep->number;
|
|
|
|
while (sp && sp->number < k)
|
|
{
|
|
sp1 = sp;
|
|
sp = sp->next;
|
|
}
|
|
|
|
if (sp && sp->number == k)
|
|
{
|
|
sp2 = (shifts *) xmalloc((unsigned) (sizeof(shifts)
|
|
+ sp->nshifts * sizeof(short)));
|
|
sp2->number = k;
|
|
sp2->nshifts = sp->nshifts + 1;
|
|
sp2->shifts[0] = nstates;
|
|
for (i = sp->nshifts; i > 0; i--)
|
|
sp2->shifts[i] = sp->shifts[i - 1];
|
|
|
|
/* Patch sp2 into the chain of shifts in place of sp,
|
|
following sp1. */
|
|
sp2->next = sp->next;
|
|
sp1->next = sp2;
|
|
if (sp == last_shift)
|
|
last_shift = sp2;
|
|
FREE(sp);
|
|
}
|
|
else
|
|
{
|
|
sp2 = NEW(shifts);
|
|
sp2->number = k;
|
|
sp2->nshifts = 1;
|
|
sp2->shifts[0] = nstates;
|
|
|
|
/* Patch sp2 into the chain of shifts between sp1 and sp. */
|
|
sp2->next = sp;
|
|
sp1->next = sp2;
|
|
if (sp == 0)
|
|
last_shift = sp2;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
/* 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). */
|
|
sp = first_shift;
|
|
|
|
sp2 = (shifts *) xmalloc(sizeof(shifts)
|
|
+ sp->nshifts * sizeof(short));
|
|
sp2->nshifts = sp->nshifts + 1;
|
|
|
|
/* Stick this shift into the vector at the proper place. */
|
|
statep = first_state->next;
|
|
for (k = 0, i = 0; i < sp->nshifts; k++, i++)
|
|
{
|
|
if (statep->accessing_symbol > start_symbol && i == k)
|
|
sp2->shifts[k++] = nstates;
|
|
sp2->shifts[k] = sp->shifts[i];
|
|
statep = statep->next;
|
|
}
|
|
if (i == k)
|
|
sp2->shifts[k++] = nstates;
|
|
|
|
/* Patch sp2 into the chain of shifts
|
|
in place of sp, at the beginning. */
|
|
sp2->next = sp->next;
|
|
first_shift = sp2;
|
|
if (last_shift == sp)
|
|
last_shift = sp2;
|
|
|
|
FREE(sp);
|
|
|
|
/* Create the next-to-final state, with shift to
|
|
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->nshifts = 1;
|
|
sp->shifts[0] = nstates;
|
|
|
|
/* Patch sp into the chain of shifts at the beginning. */
|
|
sp->next = first_shift;
|
|
first_shift = sp;
|
|
|
|
/* Create the next-to-final state, with shift to
|
|
what will be the final state. */
|
|
insert_start_shift();
|
|
}
|
|
}
|
|
else
|
|
{
|
|
/* There are no shifts for any state.
|
|
Make one shift, from the initial state to the next-to-final state. */
|
|
|
|
sp = NEW(shifts);
|
|
sp->nshifts = 1;
|
|
sp->shifts[0] = nstates;
|
|
|
|
/* Initialize the chain of shifts with sp. */
|
|
first_shift = sp;
|
|
last_shift = sp;
|
|
|
|
/* Create the next-to-final state, with shift to
|
|
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->number = nstates;
|
|
last_state->next = statep;
|
|
last_state = statep;
|
|
|
|
/* Make the shift from the final state to the termination state. */
|
|
sp = NEW(shifts);
|
|
sp->number = nstates++;
|
|
sp->nshifts = 1;
|
|
sp->shifts[0] = nstates;
|
|
last_shift->next = sp;
|
|
last_shift = sp;
|
|
|
|
/* Note that the variable `final_state' refers to what we sometimes call
|
|
the termination state. */
|
|
final_state = nstates;
|
|
|
|
/* Make the termination state. */
|
|
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. */
|
|
void
|
|
insert_start_shift()
|
|
{
|
|
register core *statep;
|
|
register shifts *sp;
|
|
|
|
statep = (core *) xmalloc((unsigned) (sizeof(core) - sizeof(short)));
|
|
statep->number = nstates;
|
|
statep->accessing_symbol = start_symbol;
|
|
|
|
last_state->next = statep;
|
|
last_state = statep;
|
|
|
|
/* 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;
|
|
|
|
last_shift->next = sp;
|
|
last_shift = sp;
|
|
}
|