ref: a609c6102f28f53a9a151804998d4e4b5347ddb5
dir: /sys/src/cmd/spin/tl_buchi.c/
/***** tl_spin: tl_buchi.c *****/
/*
* This file is part of the public release of Spin. It is subject to the
* terms in the LICENSE file that is included in this source directory.
* Tool documentation is available at http://spinroot.com
*
* Based on the translation algorithm by Gerth, Peled, Vardi, and Wolper,
* presented at the PSTV Conference, held in 1995, Warsaw, Poland 1995.
*/
#include "tl.h"
extern int tl_verbose, tl_clutter, Total, Max_Red;
extern char *claim_name;
FILE *tl_out; /* if standalone: = stdout; */
typedef struct Transition {
Symbol *name;
Node *cond;
int redundant, merged, marked;
struct Transition *nxt;
} Transition;
typedef struct State {
Symbol *name;
Transition *trans;
Graph *colors;
unsigned char redundant;
unsigned char accepting;
unsigned char reachable;
struct State *nxt;
} State;
static State *never = (State *) 0;
static int hitsall;
void
ini_buchi(void)
{
never = (State *) 0;
hitsall = 0;
}
static int
sametrans(Transition *s, Transition *t)
{
if (strcmp(s->name->name, t->name->name) != 0)
return 0;
return isequal(s->cond, t->cond);
}
static Node *
Prune(Node *p)
{
if (p)
switch (p->ntyp) {
case PREDICATE:
case NOT:
case FALSE:
case TRUE:
#ifdef NXT
case NEXT:
#endif
case CEXPR:
return p;
case OR:
p->lft = Prune(p->lft);
if (!p->lft)
{ releasenode(1, p->rgt);
return ZN;
}
p->rgt = Prune(p->rgt);
if (!p->rgt)
{ releasenode(1, p->lft);
return ZN;
}
return p;
case AND:
p->lft = Prune(p->lft);
if (!p->lft)
return Prune(p->rgt);
p->rgt = Prune(p->rgt);
if (!p->rgt)
return p->lft;
return p;
}
releasenode(1, p);
return ZN;
}
static State *
findstate(char *nm)
{ State *b;
for (b = never; b; b = b->nxt)
if (!strcmp(b->name->name, nm))
return b;
if (strcmp(nm, "accept_all"))
{ if (strncmp(nm, "accept", 6))
{ int i; char altnm[64];
for (i = 0; i < 64; i++)
if (nm[i] == '_')
break;
if (i >= 64)
Fatal("name too long %s", nm);
sprintf(altnm, "accept%s", &nm[i]);
return findstate(altnm);
}
/* Fatal("buchi: no state %s", nm); */
}
return (State *) 0;
}
static void
Dfs(State *b)
{ Transition *t;
if (!b || b->reachable) return;
b->reachable = 1;
if (b->redundant)
printf("/* redundant state %s */\n",
b->name->name);
for (t = b->trans; t; t = t->nxt)
{ if (!t->redundant)
{ Dfs(findstate(t->name->name));
if (!hitsall
&& strcmp(t->name->name, "accept_all") == 0)
hitsall = 1;
}
}
}
void
retarget(char *from, char *to)
{ State *b;
Transition *t;
Symbol *To = tl_lookup(to);
if (tl_verbose) printf("replace %s with %s\n", from, to);
for (b = never; b; b = b->nxt)
{ if (!strcmp(b->name->name, from))
b->redundant = 1;
else
for (t = b->trans; t; t = t->nxt)
{ if (!strcmp(t->name->name, from))
t->name = To;
} }
}
#ifdef NXT
static Node *
nonxt(Node *n)
{
switch (n->ntyp) {
case U_OPER:
case V_OPER:
case NEXT:
return ZN;
case OR:
n->lft = nonxt(n->lft);
n->rgt = nonxt(n->rgt);
if (!n->lft || !n->rgt)
return True;
return n;
case AND:
n->lft = nonxt(n->lft);
n->rgt = nonxt(n->rgt);
if (!n->lft)
{ if (!n->rgt)
n = ZN;
else
n = n->rgt;
} else if (!n->rgt)
n = n->lft;
return n;
}
return n;
}
#endif
static Node *
combination(Node *s, Node *t)
{ Node *nc;
#ifdef NXT
Node *a = nonxt(s);
Node *b = nonxt(t);
if (tl_verbose)
{ printf("\tnonxtA: "); dump(a);
printf("\n\tnonxtB: "); dump(b);
printf("\n");
}
/* if there's only a X(f), its equivalent to true */
if (!a || !b)
nc = True;
else
nc = tl_nn(OR, a, b);
#else
nc = tl_nn(OR, s, t);
#endif
if (tl_verbose)
{ printf("\tcombo: "); dump(nc);
printf("\n");
}
return nc;
}
Node *
unclutter(Node *n, char *snm)
{ Node *t, *s, *v, *u;
Symbol *w;
/* check only simple cases like !q && q */
for (t = n; t; t = t->rgt)
{ if (t->rgt)
{ if (t->ntyp != AND || !t->lft)
return n;
if (t->lft->ntyp != PREDICATE
#ifdef NXT
&& t->lft->ntyp != NEXT
#endif
&& t->lft->ntyp != NOT)
return n;
} else
{ if (t->ntyp != PREDICATE
#ifdef NXT
&& t->ntyp != NEXT
#endif
&& t->ntyp != NOT)
return n;
}
}
for (t = n; t; t = t->rgt)
{ if (t->rgt)
v = t->lft;
else
v = t;
if (v->ntyp == NOT
&& v->lft->ntyp == PREDICATE)
{ w = v->lft->sym;
for (s = n; s; s = s->rgt)
{ if (s == t) continue;
if (s->rgt)
u = s->lft;
else
u = s;
if (u->ntyp == PREDICATE
&& strcmp(u->sym->name, w->name) == 0)
{ if (tl_verbose)
{ printf("BINGO %s:\t", snm);
dump(n);
printf("\n");
}
return False;
}
}
} }
return n;
}
static void
clutter(void)
{ State *p;
Transition *s;
for (p = never; p; p = p->nxt)
for (s = p->trans; s; s = s->nxt)
{ s->cond = unclutter(s->cond, p->name->name);
if (s->cond
&& s->cond->ntyp == FALSE)
{ if (s != p->trans
|| s->nxt)
s->redundant = 1;
}
}
}
static void
showtrans(State *a)
{ Transition *s;
for (s = a->trans; s; s = s->nxt)
{ printf("%s ", s->name?s->name->name:"-");
dump(s->cond);
printf(" %d %d %d\n", s->redundant, s->merged, s->marked);
}
}
static int
mergetrans(void)
{ State *b;
Transition *s, *t;
Node *nc; int cnt = 0;
for (b = never; b; b = b->nxt)
{ if (!b->reachable) continue;
for (s = b->trans; s; s = s->nxt)
{ if (s->redundant) continue;
for (t = s->nxt; t; t = t->nxt)
if (!t->redundant
&& !strcmp(s->name->name, t->name->name))
{ if (tl_verbose)
{ printf("===\nstate %s, trans to %s redundant\n",
b->name->name, s->name->name);
showtrans(b);
printf(" conditions ");
dump(s->cond); printf(" <-> ");
dump(t->cond); printf("\n");
}
if (!s->cond) /* same as T */
{ releasenode(1, t->cond); /* T or t */
nc = True;
} else if (!t->cond)
{ releasenode(1, s->cond);
nc = True;
} else
{ nc = combination(s->cond, t->cond);
}
t->cond = rewrite(nc);
t->merged = 1;
s->redundant = 1;
cnt++;
break;
} } }
return cnt;
}
static int
all_trans_match(State *a, State *b)
{ Transition *s, *t;
int found, result = 0;
if (a->accepting != b->accepting)
goto done;
for (s = a->trans; s; s = s->nxt)
{ if (s->redundant) continue;
found = 0;
for (t = b->trans; t; t = t->nxt)
{ if (t->redundant) continue;
if (sametrans(s, t))
{ found = 1;
t->marked = 1;
break;
} }
if (!found)
goto done;
}
for (s = b->trans; s; s = s->nxt)
{ if (s->redundant || s->marked) continue;
found = 0;
for (t = a->trans; t; t = t->nxt)
{ if (t->redundant) continue;
if (sametrans(s, t))
{ found = 1;
break;
} }
if (!found)
goto done;
}
result = 1;
done:
for (s = b->trans; s; s = s->nxt)
s->marked = 0;
return result;
}
#ifndef NO_OPT
#define BUCKY
#endif
#ifdef BUCKY
static int
all_bucky(State *a, State *b)
{ Transition *s, *t;
int found, result = 0;
for (s = a->trans; s; s = s->nxt)
{ if (s->redundant) continue;
found = 0;
for (t = b->trans; t; t = t->nxt)
{ if (t->redundant) continue;
if (isequal(s->cond, t->cond))
{ if (strcmp(s->name->name, b->name->name) == 0
&& strcmp(t->name->name, a->name->name) == 0)
{ found = 1; /* they point to each other */
t->marked = 1;
break;
}
if (strcmp(s->name->name, t->name->name) == 0
&& strcmp(s->name->name, "accept_all") == 0)
{ found = 1;
t->marked = 1;
break;
/* same exit from which there is no return */
}
}
}
if (!found)
goto done;
}
for (s = b->trans; s; s = s->nxt)
{ if (s->redundant || s->marked) continue;
found = 0;
for (t = a->trans; t; t = t->nxt)
{ if (t->redundant) continue;
if (isequal(s->cond, t->cond))
{ if (strcmp(s->name->name, a->name->name) == 0
&& strcmp(t->name->name, b->name->name) == 0)
{ found = 1;
t->marked = 1;
break;
}
if (strcmp(s->name->name, t->name->name) == 0
&& strcmp(s->name->name, "accept_all") == 0)
{ found = 1;
t->marked = 1;
break;
}
}
}
if (!found)
goto done;
}
result = 1;
done:
for (s = b->trans; s; s = s->nxt)
s->marked = 0;
return result;
}
static int
buckyballs(void)
{ State *a, *b, *c, *d;
int m, cnt=0;
do {
m = 0; cnt++;
for (a = never; a; a = a->nxt)
{ if (!a->reachable) continue;
if (a->redundant) continue;
for (b = a->nxt; b; b = b->nxt)
{ if (!b->reachable) continue;
if (b->redundant) continue;
if (all_bucky(a, b))
{ m++;
if (tl_verbose)
{ printf("%s bucky match %s\n",
a->name->name, b->name->name);
}
if (a->accepting && !b->accepting)
{ if (strcmp(b->name->name, "T0_init") == 0)
{ c = a; d = b;
b->accepting = 1;
} else
{ c = b; d = a;
}
} else
{ c = a; d = b;
}
retarget(c->name->name, d->name->name);
if (!strncmp(c->name->name, "accept", 6)
&& Max_Red == 0)
{ char buf[64];
sprintf(buf, "T0%s", &(c->name->name[6]));
retarget(buf, d->name->name);
}
break;
}
} }
} while (m && cnt < 10);
return cnt-1;
}
#endif
static int
mergestates(int v)
{ State *a, *b;
int m, cnt=0;
if (tl_verbose)
return 0;
do {
m = 0; cnt++;
for (a = never; a; a = a->nxt)
{ if (v && !a->reachable) continue;
if (a->redundant) continue; /* 3.3.10 */
for (b = a->nxt; b; b = b->nxt)
{ if (v && !b->reachable) continue;
if (b->redundant) continue; /* 3.3.10 */
if (all_trans_match(a, b))
{ m++;
if (tl_verbose)
{ printf("%d: state %s equals state %s\n",
cnt, a->name->name, b->name->name);
showtrans(a);
printf("==\n");
showtrans(b);
}
retarget(a->name->name, b->name->name);
if (!strncmp(a->name->name, "accept", 6)
&& Max_Red == 0)
{ char buf[64];
sprintf(buf, "T0%s", &(a->name->name[6]));
retarget(buf, b->name->name);
}
break;
}
#if 0
else if (tl_verbose)
{ printf("\n%d: state %s differs from state %s [%d,%d]\n",
cnt, a->name->name, b->name->name,
a->accepting, b->accepting);
showtrans(a);
printf("==\n");
showtrans(b);
printf("\n");
}
#endif
} }
} while (m && cnt < 10);
return cnt-1;
}
static int tcnt;
static void
rev_trans(Transition *t) /* print transitions in reverse order... */
{
if (!t) return;
rev_trans(t->nxt);
if (t->redundant && !tl_verbose) return;
if (strcmp(t->name->name, "accept_all") == 0) /* 6.2.4 */
{ /* not d_step because there may be remote refs */
fprintf(tl_out, "\t:: atomic { (");
if (dump_cond(t->cond, t->cond, 1))
fprintf(tl_out, "1");
fprintf(tl_out, ") -> assert(!(");
if (dump_cond(t->cond, t->cond, 1))
fprintf(tl_out, "1");
fprintf(tl_out, ")) }\n");
} else
{ fprintf(tl_out, "\t:: (");
if (dump_cond(t->cond, t->cond, 1))
fprintf(tl_out, "1");
fprintf(tl_out, ") -> goto %s\n", t->name->name);
}
tcnt++;
}
static void
printstate(State *b)
{
if (!b || (!tl_verbose && !b->reachable)) return;
b->reachable = 0; /* print only once */
fprintf(tl_out, "%s:\n", b->name->name);
if (tl_verbose)
{ fprintf(tl_out, " /* ");
dump(b->colors->Other);
fprintf(tl_out, " */\n");
}
if (strncmp(b->name->name, "accept", 6) == 0
&& Max_Red == 0)
fprintf(tl_out, "T0%s:\n", &(b->name->name[6]));
fprintf(tl_out, "\tdo\n");
tcnt = 0;
rev_trans(b->trans);
if (!tcnt) fprintf(tl_out, "\t:: false\n");
fprintf(tl_out, "\tod;\n");
Total++;
}
void
addtrans(Graph *col, char *from, Node *op, char *to)
{ State *b;
Transition *t;
t = (Transition *) tl_emalloc(sizeof(Transition));
t->name = tl_lookup(to);
t->cond = Prune(dupnode(op));
if (tl_verbose)
{ printf("\n%s <<\t", from); dump(op);
printf("\n\t"); dump(t->cond);
printf(">> %s\n", t->name->name);
}
if (t->cond) t->cond = rewrite(t->cond);
for (b = never; b; b = b->nxt)
if (!strcmp(b->name->name, from))
{ t->nxt = b->trans;
b->trans = t;
return;
}
b = (State *) tl_emalloc(sizeof(State));
b->name = tl_lookup(from);
b->colors = col;
b->trans = t;
if (!strncmp(from, "accept", 6))
b->accepting = 1;
b->nxt = never;
never = b;
}
static void
clr_reach(void)
{ State *p;
for (p = never; p; p = p->nxt)
p->reachable = 0;
hitsall = 0;
}
void
fsm_print(void)
{ State *b; int cnt1, cnt2=0;
extern void put_uform(void);
if (tl_clutter) clutter();
b = findstate("T0_init");
if (b && (Max_Red == 0))
b->accepting = 1;
mergestates(0);
b = findstate("T0_init");
fprintf(tl_out, "never %s { /* ", claim_name?claim_name:"");
put_uform();
fprintf(tl_out, " */\n");
do {
clr_reach();
Dfs(b);
cnt1 = mergetrans();
cnt2 = mergestates(1);
if (tl_verbose)
printf("/* >>%d,%d<< */\n", cnt1, cnt2);
} while (cnt2 > 0);
#ifdef BUCKY
buckyballs();
clr_reach();
Dfs(b);
#endif
if (b && b->accepting)
fprintf(tl_out, "accept_init:\n");
if (!b && !never)
{ fprintf(tl_out, " 0 /* false */;\n");
} else
{ printstate(b); /* init state must be first */
for (b = never; b; b = b->nxt)
printstate(b);
}
if (hitsall)
fprintf(tl_out, "accept_all:\n skip\n");
fprintf(tl_out, "}\n");
}