ref: 5c1feb0ef0b795e5de71e956f9ccddcd5c4b7f21
dir: /sys/src/cmd/spin/pangen5.c/
/***** spin: pangen5.c *****/
/* Copyright (c) 1999-2003 by Lucent Technologies, Bell Laboratories. */
/* All Rights Reserved. This software is for educational purposes only. */
/* No guarantee whatsoever is expressed or implied by the distribution of */
/* this code. Permission is given to distribute this code provided that */
/* this introductory message is not removed and no monies are exchanged. */
/* Software written by Gerard J. Holzmann. For tool documentation see: */
/* http://spinroot.com/ */
/* Send all bug-reports and/or questions to: bugs@spinroot.com */
#include "spin.h"
#include "y.tab.h"
typedef struct BuildStack {
FSM_trans *t;
struct BuildStack *nxt;
} BuildStack;
extern ProcList *rdy;
extern int verbose, eventmapnr, claimnr, rvopt, export_ast, u_sync;
extern Element *Al_El;
static FSM_state *fsm_free;
static FSM_trans *trans_free;
static BuildStack *bs, *bf;
static int max_st_id;
static int cur_st_id;
int o_max;
FSM_state *fsm;
FSM_state **fsm_tbl;
FSM_use *use_free;
static void ana_seq(Sequence *);
static void ana_stmnt(FSM_trans *, Lextok *, int);
extern void AST_slice(void);
extern void AST_store(ProcList *, int);
extern int has_global(Lextok *);
extern void exit(int);
static void
fsm_table(void)
{ FSM_state *f;
max_st_id += 2;
/* fprintf(stderr, "omax %d, max=%d\n", o_max, max_st_id); */
if (o_max < max_st_id)
{ o_max = max_st_id;
fsm_tbl = (FSM_state **) emalloc(max_st_id * sizeof(FSM_state *));
} else
memset((char *)fsm_tbl, 0, max_st_id * sizeof(FSM_state *));
cur_st_id = max_st_id;
max_st_id = 0;
for (f = fsm; f; f = f->nxt)
fsm_tbl[f->from] = f;
}
static int
FSM_DFS(int from, FSM_use *u)
{ FSM_state *f;
FSM_trans *t;
FSM_use *v;
int n;
if (from == 0)
return 1;
f = fsm_tbl[from];
if (!f)
{ printf("cannot find state %d\n", from);
fatal("fsm_dfs: cannot happen\n", (char *) 0);
}
if (f->seen)
return 1;
f->seen = 1;
for (t = f->t; t; t = t->nxt)
{
for (n = 0; n < 2; n++)
for (v = t->Val[n]; v; v = v->nxt)
if (u->var == v->var)
return n; /* a read or write */
if (!FSM_DFS(t->to, u))
return 0;
}
return 1;
}
static void
new_dfs(void)
{ int i;
for (i = 0; i < cur_st_id; i++)
if (fsm_tbl[i])
fsm_tbl[i]->seen = 0;
}
static int
good_dead(Element *e, FSM_use *u)
{
switch (u->special) {
case 2: /* ok if it's a receive */
if (e->n->ntyp == ASGN
&& e->n->rgt->ntyp == CONST
&& e->n->rgt->val == 0)
return 0;
break;
case 1: /* must be able to use oval */
if (e->n->ntyp != 'c'
&& e->n->ntyp != 'r')
return 0; /* can't really happen */
break;
}
return 1;
}
#if 0
static int howdeep = 0;
#endif
static int
eligible(FSM_trans *v)
{ Element *el = ZE;
Lextok *lt = ZN;
if (v) el = v->step;
if (el) lt = v->step->n;
if (!lt /* dead end */
|| v->nxt /* has alternatives */
|| el->esc /* has an escape */
|| (el->status&CHECK2) /* remotely referenced */
|| lt->ntyp == ATOMIC
|| lt->ntyp == NON_ATOMIC /* used for inlines -- should be able to handle this */
|| lt->ntyp == IF
|| lt->ntyp == C_CODE
|| lt->ntyp == C_EXPR
|| has_lab(el, 0) /* any label at all */
|| lt->ntyp == DO
|| lt->ntyp == UNLESS
|| lt->ntyp == D_STEP
|| lt->ntyp == ELSE
|| lt->ntyp == '@'
|| lt->ntyp == 'c'
|| lt->ntyp == 'r'
|| lt->ntyp == 's')
return 0;
if (!(el->status&(2|4))) /* not atomic */
{ int unsafe = (el->status&I_GLOB)?1:has_global(el->n);
if (unsafe)
return 0;
}
return 1;
}
static int
canfill_in(FSM_trans *v)
{ Element *el = v->step;
Lextok *lt = v->step->n;
if (!lt /* dead end */
|| v->nxt /* has alternatives */
|| el->esc /* has an escape */
|| (el->status&CHECK2)) /* remotely referenced */
return 0;
if (!(el->status&(2|4)) /* not atomic */
&& ((el->status&I_GLOB)
|| has_global(el->n))) /* and not safe */
return 0;
return 1;
}
static int
pushbuild(FSM_trans *v)
{ BuildStack *b;
for (b = bs; b; b = b->nxt)
if (b->t == v)
return 0;
if (bf)
{ b = bf;
bf = bf->nxt;
} else
b = (BuildStack *) emalloc(sizeof(BuildStack));
b->t = v;
b->nxt = bs;
bs = b;
return 1;
}
static void
popbuild(void)
{ BuildStack *f;
if (!bs)
fatal("cannot happen, popbuild", (char *) 0);
f = bs;
bs = bs->nxt;
f->nxt = bf;
bf = f; /* freelist */
}
static int
build_step(FSM_trans *v)
{ FSM_state *f;
Element *el = v->step;
#if 0
Lextok *lt = ZN;
#endif
int st = v->to;
int r;
if (!el) return -1;
if (v->step->merge)
return v->step->merge; /* already done */
if (!eligible(v)) /* non-blocking */
return -1;
if (!pushbuild(v)) /* cycle detected */
return -1; /* break cycle */
f = fsm_tbl[st];
#if 0
lt = v->step->n;
if (verbose&32)
{ if (++howdeep == 1)
printf("spin: %s, line %3d, merge:\n",
lt->fn->name,
lt->ln);
printf("\t[%d] <seqno %d>\t", howdeep, el->seqno);
comment(stdout, lt, 0);
printf(";\n");
}
#endif
r = build_step(f->t);
v->step->merge = (r == -1) ? st : r;
#if 0
if (verbose&32)
{ printf(" merge value: %d (st=%d,r=%d, line %d)\n",
v->step->merge, st, r, el->n->ln);
howdeep--;
}
#endif
popbuild();
return v->step->merge;
}
static void
FSM_MERGER(char *pname_unused) /* find candidates for safely merging steps */
{ FSM_state *f, *g;
FSM_trans *t;
Lextok *lt;
for (f = fsm; f; f = f->nxt) /* all states */
for (t = f->t; t; t = t->nxt) /* all edges */
{ if (!t->step) continue; /* happens with 'unless' */
t->step->merge_in = f->in; /* ?? */
if (t->step->merge)
continue;
lt = t->step->n;
if (lt->ntyp == 'c'
|| lt->ntyp == 'r'
|| lt->ntyp == 's') /* blocking stmnts */
continue; /* handled in 2nd scan */
if (!eligible(t))
continue;
g = fsm_tbl[t->to];
if (!eligible(g->t))
{
#define SINGLES
#ifdef SINGLES
t->step->merge_single = t->to;
#if 0
if ((verbose&32))
{ printf("spin: %s, line %3d, merge_single:\n\t<seqno %d>\t",
t->step->n->fn->name,
t->step->n->ln,
t->step->seqno);
comment(stdout, t->step->n, 0);
printf(";\n");
}
#endif
#endif
/* t is an isolated eligible step:
*
* a merge_start can connect to a proper
* merge chain or to a merge_single
* a merge chain can be preceded by
* a merge_start, but not by a merge_single
*/
continue;
}
(void) build_step(t);
}
/* 2nd scan -- find possible merge_starts */
for (f = fsm; f; f = f->nxt) /* all states */
for (t = f->t; t; t = t->nxt) /* all edges */
{ if (!t->step || t->step->merge)
continue;
lt = t->step->n;
#if 0
4.1.3:
an rv send operation inside an atomic, *loses* atomicity
when executed
and should therefore never be merged with a subsequent
statement within the atomic sequence
the same is not true for non-rv send operations
#endif
if (lt->ntyp == 'c' /* potentially blocking stmnts */
|| lt->ntyp == 'r'
|| (lt->ntyp == 's' && u_sync == 0)) /* added !u_sync in 4.1.3 */
{ if (!canfill_in(t)) /* atomic, non-global, etc. */
continue;
g = fsm_tbl[t->to];
if (!g || !g->t || !g->t->step)
continue;
if (g->t->step->merge)
t->step->merge_start = g->t->step->merge;
#ifdef SINGLES
else if (g->t->step->merge_single)
t->step->merge_start = g->t->step->merge_single;
#endif
#if 0
if ((verbose&32)
&& t->step->merge_start)
{ printf("spin: %s, line %3d, merge_START:\n\t<seqno %d>\t",
lt->fn->name,
lt->ln,
t->step->seqno);
comment(stdout, lt, 0);
printf(";\n");
}
#endif
}
}
}
static void
FSM_ANA(void)
{ FSM_state *f;
FSM_trans *t;
FSM_use *u, *v, *w;
int n;
for (f = fsm; f; f = f->nxt) /* all states */
for (t = f->t; t; t = t->nxt) /* all edges */
for (n = 0; n < 2; n++) /* reads and writes */
for (u = t->Val[n]; u; u = u->nxt)
{ if (!u->var->context /* global */
|| u->var->type == CHAN
|| u->var->type == STRUCT)
continue;
new_dfs();
if (FSM_DFS(t->to, u)) /* cannot hit read before hitting write */
u->special = n+1; /* means, reset to 0 after use */
}
if (!export_ast)
for (f = fsm; f; f = f->nxt)
for (t = f->t; t; t = t->nxt)
for (n = 0; n < 2; n++)
for (u = t->Val[n], w = (FSM_use *) 0; u; )
{ if (u->special)
{ v = u->nxt;
if (!w) /* remove from list */
t->Val[n] = v;
else
w->nxt = v;
#if q
if (verbose&32)
{ printf("%s : %3d: %d -> %d \t",
t->step->n->fn->name,
t->step->n->ln,
f->from,
t->to);
comment(stdout, t->step->n, 0);
printf("\t%c%d: %s\n", n==0?'R':'L',
u->special, u->var->name);
}
#endif
if (good_dead(t->step, u))
{ u->nxt = t->step->dead; /* insert into dead */
t->step->dead = u;
}
u = v;
} else
{ w = u;
u = u->nxt;
} }
}
void
rel_use(FSM_use *u)
{
if (!u) return;
rel_use(u->nxt);
u->var = (Symbol *) 0;
u->special = 0;
u->nxt = use_free;
use_free = u;
}
static void
rel_trans(FSM_trans *t)
{
if (!t) return;
rel_trans(t->nxt);
rel_use(t->Val[0]);
rel_use(t->Val[1]);
t->Val[0] = t->Val[1] = (FSM_use *) 0;
t->nxt = trans_free;
trans_free = t;
}
static void
rel_state(FSM_state *f)
{
if (!f) return;
rel_state(f->nxt);
rel_trans(f->t);
f->t = (FSM_trans *) 0;
f->nxt = fsm_free;
fsm_free = f;
}
static void
FSM_DEL(void)
{
rel_state(fsm);
fsm = (FSM_state *) 0;
}
static FSM_state *
mkstate(int s)
{ FSM_state *f;
/* fsm_tbl isn't allocated yet */
for (f = fsm; f; f = f->nxt)
if (f->from == s)
break;
if (!f)
{ if (fsm_free)
{ f = fsm_free;
memset(f, 0, sizeof(FSM_state));
fsm_free = fsm_free->nxt;
} else
f = (FSM_state *) emalloc(sizeof(FSM_state));
f->from = s;
f->t = (FSM_trans *) 0;
f->nxt = fsm;
fsm = f;
if (s > max_st_id)
max_st_id = s;
}
return f;
}
static FSM_trans *
get_trans(int to)
{ FSM_trans *t;
if (trans_free)
{ t = trans_free;
memset(t, 0, sizeof(FSM_trans));
trans_free = trans_free->nxt;
} else
t = (FSM_trans *) emalloc(sizeof(FSM_trans));
t->to = to;
return t;
}
static void
FSM_EDGE(int from, int to, Element *e)
{ FSM_state *f;
FSM_trans *t;
f = mkstate(from); /* find it or else make it */
t = get_trans(to);
t->step = e;
t->nxt = f->t;
f->t = t;
f = mkstate(to);
f->in++;
if (export_ast)
{ t = get_trans(from);
t->step = e;
t->nxt = f->p; /* from is a predecessor of to */
f->p = t;
}
if (t->step)
ana_stmnt(t, t->step->n, 0);
}
#define LVAL 1
#define RVAL 0
static void
ana_var(FSM_trans *t, Lextok *now, int usage)
{ FSM_use *u, *v;
if (!t || !now || !now->sym)
return;
if (now->sym->name[0] == '_'
&& (strcmp(now->sym->name, "_") == 0
|| strcmp(now->sym->name, "_pid") == 0
|| strcmp(now->sym->name, "_last") == 0))
return;
v = t->Val[usage];
for (u = v; u; u = u->nxt)
if (u->var == now->sym)
return; /* it's already there */
if (!now->lft)
{ /* not for array vars -- it's hard to tell statically
if the index would, at runtime, evaluate to the
same values at lval and rval references
*/
if (use_free)
{ u = use_free;
use_free = use_free->nxt;
} else
u = (FSM_use *) emalloc(sizeof(FSM_use));
u->var = now->sym;
u->nxt = t->Val[usage];
t->Val[usage] = u;
} else
ana_stmnt(t, now->lft, RVAL); /* index */
if (now->sym->type == STRUCT
&& now->rgt
&& now->rgt->lft)
ana_var(t, now->rgt->lft, usage);
}
static void
ana_stmnt(FSM_trans *t, Lextok *now, int usage)
{ Lextok *v;
if (!t || !now) return;
switch (now->ntyp) {
case '.':
case BREAK:
case GOTO:
case CONST:
case TIMEOUT:
case NONPROGRESS:
case ELSE:
case '@':
case 'q':
case IF:
case DO:
case ATOMIC:
case NON_ATOMIC:
case D_STEP:
case C_CODE:
case C_EXPR:
break;
case '!':
case UMIN:
case '~':
case ENABLED:
case PC_VAL:
case LEN:
case FULL:
case EMPTY:
case NFULL:
case NEMPTY:
case ASSERT:
case 'c':
ana_stmnt(t, now->lft, RVAL);
break;
case '/':
case '*':
case '-':
case '+':
case '%':
case '&':
case '^':
case '|':
case LT:
case GT:
case LE:
case GE:
case NE:
case EQ:
case OR:
case AND:
case LSHIFT:
case RSHIFT:
ana_stmnt(t, now->lft, RVAL);
ana_stmnt(t, now->rgt, RVAL);
break;
case ASGN:
ana_stmnt(t, now->lft, LVAL);
ana_stmnt(t, now->rgt, RVAL);
break;
case PRINT:
case RUN:
for (v = now->lft; v; v = v->rgt)
ana_stmnt(t, v->lft, RVAL);
break;
case PRINTM:
if (now->lft && !now->lft->ismtyp)
ana_stmnt(t, now->lft, RVAL);
break;
case 's':
ana_stmnt(t, now->lft, RVAL);
for (v = now->rgt; v; v = v->rgt)
ana_stmnt(t, v->lft, RVAL);
break;
case 'R':
case 'r':
ana_stmnt(t, now->lft, RVAL);
for (v = now->rgt; v; v = v->rgt)
{ if (v->lft->ntyp == EVAL)
ana_stmnt(t, v->lft->lft, RVAL);
else
if (v->lft->ntyp != CONST
&& now->ntyp != 'R') /* was v->lft->ntyp */
ana_stmnt(t, v->lft, LVAL);
}
break;
case '?':
ana_stmnt(t, now->lft, RVAL);
if (now->rgt)
{ ana_stmnt(t, now->rgt->lft, RVAL);
ana_stmnt(t, now->rgt->rgt, RVAL);
}
break;
case NAME:
ana_var(t, now, usage);
break;
case 'p': /* remote ref */
ana_stmnt(t, now->lft->lft, RVAL); /* process id */
ana_var(t, now, RVAL);
ana_var(t, now->rgt, RVAL);
break;
default:
printf("spin: bad node type %d line %d (ana_stmnt)\n", now->ntyp, now->ln);
fatal("aborting", (char *) 0);
}
}
void
ana_src(int dataflow, int merger) /* called from main.c and guided.c */
{ ProcList *p;
Element *e;
#if 0
int counter = 1;
#endif
for (p = rdy; p; p = p->nxt)
{ if (p->tn == eventmapnr
|| p->tn == claimnr)
continue;
ana_seq(p->s);
fsm_table();
e = p->s->frst;
#if 0
if (dataflow || merger)
{ printf("spin: %d, optimizing '%s'",
counter++, p->n->name);
fflush(stdout);
}
#endif
if (dataflow)
{ FSM_ANA();
}
if (merger)
{ FSM_MERGER(p->n->name);
huntele(e, e->status, -1)->merge_in = 1; /* start-state */
#if 0
printf("\n");
#endif
}
if (export_ast)
AST_store(p, huntele(e, e->status, -1)->seqno);
FSM_DEL();
}
for (e = Al_El; e; e = e->Nxt)
{
if (!(e->status&DONE) && (verbose&32))
{ printf("unreachable code: ");
printf("%s, line %3d: ",
e->n->fn->name, e->n->ln);
comment(stdout, e->n, 0);
printf("\n");
}
e->status &= ~DONE;
}
if (export_ast)
{ AST_slice();
exit(0);
}
}
void
spit_recvs(FILE *f1, FILE *f2) /* called from pangen2.c */
{ Element *e;
Sequence *s;
extern int Unique;
fprintf(f1, "unsigned char Is_Recv[%d];\n", Unique);
fprintf(f2, "void\nset_recvs(void)\n{\n");
for (e = Al_El; e; e = e->Nxt)
{ if (!e->n) continue;
switch (e->n->ntyp) {
case 'r':
markit: fprintf(f2, "\tIs_Recv[%d] = 1;\n", e->Seqno);
break;
case D_STEP:
s = e->n->sl->this;
switch (s->frst->n->ntyp) {
case DO:
fatal("unexpected: do at start of d_step", (char *) 0);
case IF: /* conservative: fall through */
case 'r': goto markit;
}
break;
}
}
fprintf(f2, "}\n");
if (rvopt)
{
fprintf(f2, "int\nno_recvs(int me)\n{\n");
fprintf(f2, " int h; uchar ot; short tt;\n");
fprintf(f2, " Trans *t;\n");
fprintf(f2, " for (h = BASE; h < (int) now._nr_pr; h++)\n");
fprintf(f2, " { if (h == me) continue;\n");
fprintf(f2, " tt = (short) ((P0 *)pptr(h))->_p;\n");
fprintf(f2, " ot = (uchar) ((P0 *)pptr(h))->_t;\n");
fprintf(f2, " for (t = trans[ot][tt]; t; t = t->nxt)\n");
fprintf(f2, " if (Is_Recv[t->t_id]) return 0;\n");
fprintf(f2, " }\n");
fprintf(f2, " return 1;\n");
fprintf(f2, "}\n");
}
}
static void
ana_seq(Sequence *s)
{ SeqList *h;
Sequence *t;
Element *e, *g;
int From, To;
for (e = s->frst; e; e = e->nxt)
{ if (e->status & DONE)
goto checklast;
e->status |= DONE;
From = e->seqno;
if (e->n->ntyp == UNLESS)
ana_seq(e->sub->this);
else if (e->sub)
{ for (h = e->sub; h; h = h->nxt)
{ g = huntstart(h->this->frst);
To = g->seqno;
if (g->n->ntyp != 'c'
|| g->n->lft->ntyp != CONST
|| g->n->lft->val != 0
|| g->esc)
FSM_EDGE(From, To, e);
/* else it's a dead link */
}
for (h = e->sub; h; h = h->nxt)
ana_seq(h->this);
} else if (e->n->ntyp == ATOMIC
|| e->n->ntyp == D_STEP
|| e->n->ntyp == NON_ATOMIC)
{
t = e->n->sl->this;
g = huntstart(t->frst);
t->last->nxt = e->nxt;
To = g->seqno;
FSM_EDGE(From, To, e);
ana_seq(t);
} else
{ if (e->n->ntyp == GOTO)
{ g = get_lab(e->n, 1);
g = huntele(g, e->status, -1);
To = g->seqno;
} else if (e->nxt)
{ g = huntele(e->nxt, e->status, -1);
To = g->seqno;
} else
To = 0;
FSM_EDGE(From, To, e);
if (e->esc
&& e->n->ntyp != GOTO
&& e->n->ntyp != '.')
for (h = e->esc; h; h = h->nxt)
{ g = huntstart(h->this->frst);
To = g->seqno;
FSM_EDGE(From, To, ZE);
ana_seq(h->this);
}
}
checklast: if (e == s->last)
break;
}
}