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#include "lisc.h"
Bits
liveon(Blk *b, Blk *s)
{
Bits v;
Phi *p;
uint a;
v = s->in;
for (p=s->phi; p; p=p->link) {
BCLR(v, p->to.val);
for (a=0; a<p->narg; a++)
if (p->blk[a] == b)
if (rtype(p->arg[a]) == RTmp)
BSET(v, p->arg[a].val);
}
return v;
}
static void
phifix(int t1, short *phi, Tmp *tmp)
{
int t, t2;
/* detect temporaries in the same
* phi-class that interfere and
* separate them
*/
t = phirepr(tmp, t1);
t2 = phi[t];
if (t2 && t2 != t1) {
if (tmp[t1].phi != t1) {
tmp[t1].phi = t1;
t = t1;
} else {
tmp[t2].phi = t2;
phi[t2] = t2;
}
}
phi[t] = t1;
}
static void
bset(Ref r, Blk *b, int *nlv, short *phi, Tmp *tmp)
{
if (rtype(r) != RTmp)
return;
BSET(b->gen, r.val);
phifix(r.val, phi, tmp);
if (!BGET(b->in, r.val)) {
++*nlv;
BSET(b->in, r.val);
}
}
/* liveness analysis
* requires rpo computation
*/
void
filllive(Fn *f)
{
Blk *b;
Ins *i;
int t, z, m, n, chg, nlv;
short *phi;
Bits u, v;
Mem *ma;
assert(f->ntmp <= NBit*BITS);
phi = emalloc(f->ntmp * sizeof phi[0]);
for (b=f->start; b; b=b->link) {
b->in = (Bits){{0}};
b->out = (Bits){{0}};
b->gen = (Bits){{0}};
}
chg = 1;
Again:
for (n=f->nblk-1; n>=0; n--) {
b = f->rpo[n];
u = b->out;
if (b->s1) {
v = liveon(b, b->s1);
for (z=0; z<BITS; z++)
b->out.t[z] |= v.t[z];
}
if (b->s2) {
v = liveon(b, b->s2);
for (z=0; z<BITS; z++)
b->out.t[z] |= v.t[z];
}
chg |= memcmp(&b->out, &u, sizeof(Bits));
memset(phi, 0, f->ntmp * sizeof phi[0]);
b->in = b->out;
nlv = bcnt(&b->in);
for (t=0; t<f->ntmp; t++)
if (BGET(b->in, t))
phifix(t, phi, f->tmp);
bset(b->jmp.arg, b, &nlv, phi, f->tmp);
b->nlive = nlv;
for (i=&b->ins[b->nins]; i!=b->ins;) {
if ((--i)->op == OCall) {
b->in.t[0] &= ~calldef(*i, &m);
nlv -= m;
if (nlv + NRSave > b->nlive)
b->nlive = nlv + NRSave;
b->in.t[0] |= calluse(*i, &m);
nlv += m;
}
if (!req(i->to, R)) {
assert(rtype(i->to) == RTmp);
nlv -= BGET(b->in, i->to.val);
BSET(b->gen, i->to.val);
BCLR(b->in, i->to.val);
t = phirepr(f->tmp, i->to.val);
phi[t] = 0;
}
for (m=0; m<2; m++)
switch (rtype(i->arg[m])) {
case RAMem:
ma = &f->mem[i->arg[m].val & AMask];
bset(ma->base, b, &nlv, phi, f->tmp);
bset(ma->index, b, &nlv, phi, f->tmp);
break;
default:
bset(i->arg[m], b, &nlv, phi, f->tmp);
break;
}
if (nlv > b->nlive)
b->nlive = nlv;
}
}
if (chg) {
chg = 0;
goto Again;
}
free(phi);
if (debug['L']) {
fprintf(stderr, "\n> Liveness analysis:\n");
for (b=f->start; b; b=b->link) {
fprintf(stderr, "\t%-10sin: ", b->name);
dumpts(&b->in, f->tmp, stderr);
fprintf(stderr, "\t out: ");
dumpts(&b->out, f->tmp, stderr);
fprintf(stderr, "\t gen: ");
dumpts(&b->gen, f->tmp, stderr);
fprintf(stderr, "\t live: %d\n", b->nlive);
}
}
}
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