Reaching *reaching(Cfg *cfg)
{
Bitset **in, **out;
Bitset **gen, **kill;
Bitset *bbin, *bbout;
Reaching *reaching;
size_t **defs; /* mapping from did => [def,list] */
size_t *ndefs;
size_t i, j;
int changed;
in = zalloc(cfg->nbb * sizeof(Bb*));
out = zalloc(cfg->nbb * sizeof(Bb*));
gen = zalloc(cfg->nbb * sizeof(Bb*));
kill = zalloc(cfg->nbb * sizeof(Bb*));
defs = zalloc(ndecls * sizeof(size_t*));
ndefs = zalloc(ndecls * sizeof(size_t));
collectdefs(cfg, defs, ndefs);
for (i = 0; i < cfg->nbb; i++) {
in[i] = mkbs();
out[i] = mkbs();
gen[i] = mkbs();
kill[i] = mkbs();
if (cfg->bb[i])
genkill(cfg->bb[i], defs, ndefs, gen[i], kill[i]);
}
do {
changed = 0;
for (i = 0; i < cfg->nbb; i++) {
if (!cfg->bb[i])
continue;
bbin = mkbs();
for (j = 0; bsiter(cfg->bb[i]->pred, &j); j++)
bsunion(bbin, out[j]);
bbout = bsdup(bbin);
bsdiff(bbout, kill[i]);
bsunion(bbout, gen[i]);
if (!bseq(out[i], bbout) || !bseq(in[i], bbin)) {
changed = 1;
bsfree(in[i]);
bsfree(out[i]);
in[i] = bbin;
out[i] = bbout;
}
}
} while (changed);
reaching = xalloc(sizeof(Reaching));
reaching->in = in;
reaching->out = out;
reaching->defs = defs;
reaching->ndefs = ndefs;
return reaching;
}
static Bb *mkbb(Cfg *cfg)
{
Bb *bb;
bb = zalloc(sizeof(Bb));
bb->id = cfg->nextbbid++;
bb->pred = mkbs();
bb->succ = mkbs();
lappend(&cfg->bb, &cfg->nbb, bb);
return bb;
}
static void checkreach(Cfg *cfg)
{
Bitset *reach, *kill;
size_t i, j, k;
Reaching *r;
Node *n, *m;
Bb *bb;
r = reaching(cfg);
// dumpcfg(cfg, stdout);
for (i = 0; i < cfg->nbb; i++) {
bb = cfg->bb[i];
if (!bb)
continue;
reach = bsdup(r->in[i]);
kill = mkbs();
for (j = 0; j < bb->nnl; j++) {
n = bb->nl[j];
if (exprop(n) == Oundef) {
bsput(reach, n->nid);
} else {
m = assignee(n);
if (m)
for (k = 0; k < r->ndefs[m->expr.did]; k++)
bsput(kill, r->defs[m->expr.did][k]);
checkundef(n, r, reach, kill);
}
}
bsfree(reach);
bsfree(kill);
}
}
