ref: e3aee39a389700ad821a1619f114e226c1bd42d0
dir: /sys/src/cmd/8c/bound.c/
#include "gc.h"
#include "bound.h"
static BB* bbfree;
static BBset* bbsfree;
static int bballoc;
static int bbsalloc;
static BB bbz;
static BBset bbsz;
static BB* firstbb;
static BB* lastbb;
static BB* wounded;
static BB* bbaux;
static BBset* recalc;
static BBset* bbhash[BBHASH];
static BB** ordered;
static int bcount;
static BBset** heap;
static int heapn;
static int bsize;
static char bbbuff[BBBSIZE];
static int bchange;
#define bdebug (debug['v'])
#define dbg 0
#define bcheck 0
static long
Rn(Reg *r)
{
if(r == R)
return -1;
return r->rpo;
}
static BB*
bba(void)
{
BB *b;
bballoc++;
b = bbfree;
if(b == nil) {
b = alloc(sizeof(*b));
} else
bbfree = b->link;
*b = bbz;
return b;
}
static void
bfree(BB *b)
{
bballoc--;
b->link = bbfree;
bbfree = b;
}
static BBset*
bbsa(void)
{
BBset *b;
bballoc++;
b = bbsfree;
if(b == nil) {
b = alloc(sizeof(*b));
} else
bbsfree = b->link;
*b = bbsz;
return b;
}
static void
bsfree(BBset *b)
{
bballoc--;
b->link = bbsfree;
bbsfree = b;
}
static void
dumpheap(void)
{
int i;
for(i = 1; i <= heapn; i++)
print(" %d", heap[i]->damage);
}
static void
checkheap(void)
{
int N, N2, n, c;
N = heapn;
N2 = N >> 1;
for(n = 1; n <= N2; n++) {
c = n << 1;
if((heap[c]->damage > heap[n]->damage)
|| ((c < N) && (heap[c + 1]->damage > heap[n]->damage))) {
print("bad heap (%d:%d) %d [", n, heap[n]->damage, heapn);
dumpheap();
print(" ]\n");
abort();
}
}
}
static void
downheap(int n)
{
int N, N2, d, c;
BBset *s, *t, *u;
s = heap[n];
d = s->damage;
//print("down %d %d", n, d);
N = heapn;
N2 = N >> 1;
while(n <= N2) {
c = n << 1;
t = heap[c];
if(c < N) {
u = heap[c + 1];
if(t->damage < u->damage) {
t = u;
c++;
}
}
//print(" [%d %d]", c, t->damage);
if(t->damage < d)
break;
heap[n] = t;
t->index = n;
n = c;
}
heap[n] = s;
s->index = n;
//print("\n");
//checkheap();
}
static void
upheap(int n)
{
int f, d;
BBset *s, *t;
s = heap[n];
d = s->damage;
//print("up %d %d", n, d);
while(n > 1) {
f = n >> 1;
t = heap[f];
//print(" [%d %d]", f, t->damage);
if(t->damage >= d)
break;
heap[n] = t;
t->index = n;
n = f;
}
heap[n] = s;
s->index = n;
//print("\n");
//checkheap();
}
static void
heapremove(BBset *s)
{
int x;
BBset *t;
x = s->index;
s->index = 0;
if(x == 0)
return;
if(x == heapn) {
heapn--;
return;
}
t = heap[heapn--];
heap[x] = t;
t->index = x;
if(s->damage < t->damage)
upheap(x);
else
downheap(x);
}
static void
heapadd(BBset *s)
{
int n;
n = heapn + 1;
heap[n] = s;
s->index = n;
heapn = n;
upheap(n);
}
static void
bbsrecalc(BBset *s)
{
if(s->recalc)
return;
s->recalc = 1;
s->link = recalc;
recalc = s;
heapremove(s);
}
static void
bbadd(BB *b, Hval h)
{
int k;
BBset *s;
k = h[0] & BBMASK;
for(s = bbhash[k]; s != nil; s = s->next) {
if(BBEQ(s->hash, h)) {
b->set = s;
b->link = s->ents;
s->ents = b;
bbsrecalc(s);
return;
}
}
s = bbsa();
s->next = bbhash[k];
bbhash[k] = s;
b->set = s;
b->link = nil;
s->ents = b;
BBCP(s->hash, h);
bbsrecalc(s);
}
static int
hashbb(BB *b, Hval h)
{
Reg *r;
Prog *p;
char *s;
int c, f, i, n;
r = b->first;
s = bbbuff;
i = 0;
n = BBBSIZE;
for(;;) {
p = r->prog;
if(p->as != ANOP) {
if(p->to.type == D_BRANCH)
p->to.offset = r->s2->rpo;
c = snprint(s, n, "%P", p);
s += c;
n -= c;
i++;
}
if(r == b->last)
break;
r = r->link;
}
if(n == 0)
return Bbig;
b->len = i;
BBMKHASH(bbbuff, BBBSIZE - n, h);
f = b->flags;
if(i == 1 && r->prog->as == AJMP && b->first->p1 == R)
f = Bjo;
else if(b->first->p1 != R)
f |= Bpre;
if(bdebug)
print("A %x %s %ux %ux\n", f, bbbuff, h[0], h[1]);
return f;
}
static void
enterbb(BB *b)
{
Hval h;
b->flags = hashbb(b, h);
if(b->flags != Bbig)
bbadd(b, h);
}
static void
preproc(BB *b, int x)
{
BB *n;
Reg *r;
ordered[x] = b;
if(b->last->rpo - b->first->rpo > BBBIG) {
b->flags = Bbig;
return;
}
if(b->first->p2 == nil) {
b->flags = Bdel;
return;
}
switch(b->last->prog->as) {
case ARET:
case AJMP:
case AIRETL:
break;
default:
b->flags = Bdel;
n = bba();
n->first = b->first;
for(r = b->last->link; r != R; r = r->link) {
switch(r->prog->as) {
case ARET:
case AJMP:
case AIRETL:
n->last = r;
n->flags = Bpin;
enterbb(n);
if(n->flags & Bpin) {
n->aux = bbaux;
bbaux = n;
}
else
bfree(n);
return;
}
}
bfree(n);
return;
}
enterbb(b);
}
static int
p2len(Reg *r)
{
int c;
c = 0;
for(r = r->p2; r != nil; r = r->p2link)
c++;
return c;
}
static void
calcdamage(BBset *s)
{
BB *f;
int d, t;
s->recalc = 0;
f = s->ents;
if(f == nil)
return;
if(f->flags & Bjo) {
if(bdebug)
print("add %ld jo\n", f->first->rpo);
s->damage = COSTJO;
heapadd(s);
return;
}
if(f->link == nil) {
if(bdebug)
print("solo %x %x\n", s->hash[0], s->hash[1]);
return;
}
d = 0;
t = 0;
while(f != nil) {
if((f->flags & (Bpre|Bpin)) == 0 && f->last->link != R) {
t = 1;
d += (f->last->rpo - f->first->rpo) >> 1;
}
d += p2len(f->first);
f = f->link;
}
if(t == 0) {
if(bdebug)
print("all pre %ld\n", s->ents->first->rpo);
return;
}
if(bdebug)
print("add %ld %d\n", s->ents->first->rpo, d);
if(d > COSTHI)
d = COSTHI;
s->damage = d;
heapadd(s);
}
static Reg*
findjump(BB *b)
{
Reg *r, *l;
r = b->first;
l = b->last;
for(;;) {
if(r->prog->as == AJMP)
break;
if(r == l) {
diag(Z, "findjump botch");
break;
}
r = r->link;
}
return r;
}
static BB*
findset(int r)
{
BB *s, **p;
int n, n2;
if(r < ordered[0]->first->rpo)
return nil;
n = bcount;
p = ordered;
while(n > 0) {
n2 = n >> 1;
s = p[n2];
if(r < s->first->rpo) {
n = n2;
continue;
}
if(r > s->last->rpo) {
n2++;
p += n2;
n -= n2;
continue;
}
return s;
}
diag(Z, "findset botch");
return nil;
}
static void
wound(Reg *r)
{
BB *b, *p, **n;
BBset *s;
b = findset(r->rpo);
if(b == nil)
return;
s = b->set;
if(s == nil)
return;
for(n = &s->ents; (p = *n) != nil; n = &(*n)->link) {
if(p == b) {
*n = b->link;
b->link = wounded;
wounded = b;
bbsrecalc(s);
return;
}
}
}
static void
printbl(Reg *l)
{
if(l == nil) {
print("Z");
return;
}
print("%ld", l->rpo);
while((l = l->p2link) != nil)
print(" %ld", l->rpo);
}
static void
appset(Reg *e, Reg *s)
{
for(;;) {
if(s->p2link == R) {
s->p2link = e;
return;
}
s = s->p2link;
}
}
static Reg*
delset(Reg *e, Reg *s)
{
Reg *c, *l;
c = s;
l = nil;
for(;;) {
if(e == c) {
if(l == nil)
return s->p2link;
l->p2link = c->p2link;
return s;
}
l = c;
c = c->p2link;
if(c == nil)
return s;
}
}
static void
redest(Reg *s, Reg *d)
{
while(s != R) {
s->s2 = d;
s = s->p2link;
}
}
static void
changedest(Reg *s, Reg *d, int x)
{
Reg *l;
if(bdebug) {
print("change %ld [", s->rpo);
printbl(s->p2);
print("] -> %ld [", d->rpo);
printbl(d->p2);
print("]\n");
}
if(s->p2 == nil) {
// print("deadjmp\n");
return;
}
l = s->p2;
for(;;) {
if(bdebug)
print("s2 %ld = %ld\n", l->rpo, d->rpo);
l->s2 = d;
wound(l);
if(l->p2link == nil)
break;
l = l->p2link;
}
if(x) {
l->p2link = delset(s, d->p2);
d->p2 = s->p2;
}
else {
l->p2link = d->p2;
d->p2 = s->p2;
s->p2 = nil;
}
if(bdebug) {
print("result [");
printbl(d->p2);
print("]\n");
}
bchange = 1;
}
static void
bexcise(BB *b)
{
Reg *r, *l;
l = b->last;
r = b->first;
if(bdebug)
print("excise %ld to %ld\n", r->rpo, l->rpo);
for(;;) {
r->prog->as = ANOP;
r->prog->to.type = D_NONE;
r->p2 = R;
if(r->s2 != R) {
r->s2->p2 = delset(r, r->s2->p2);
r->s2 = R;
}
if(r == l)
break;
r = r->link;
}
}
static int
backtrack(Reg *s, Reg *d)
{
int i;
char l[BINST], r[BINST];
//print("backtrack %ld %ld\n", Rn(s), Rn(d));
i = 0;
while(s != nil && d != nil) {
if(snprint(l, BINST, "%P", s->prog) == BINST)
break;
if(snprint(r, BINST, "%P", d->prog) == BINST)
break;
//print("%s\t%s\n", l, r);
if(strcmp(l, r) != 0)
break;
i++;
s = s->p2link;
d = d->p2link;
}
return i;
}
static void
checktails(void)
{
int c;
Reg *r;
c = 0;
for(r = firstr; r->link != R; r = r->link) {
if(r->prog->as == AJMP && r->s2 != nil)
c += backtrack(r->p1, r->s2->p1);
}
if(c > 0)
print("tails %s %d\n", firstr->prog->from.sym->name, c);
}
static void
process(BBset *s)
{
Reg *h;
BB *f, *o, *p, *t;
if(bdebug)
print("process %d %x %x\n", s->damage, s->hash[0], s->hash[1]);
f = s->ents;
if(f->flags & Bjo) {
s->ents = nil;
h = findjump(f)->s2;
o = nil;
while(f != nil) {
t = f->link;
if((f->flags & Bjo) != 0 && f->first->s2 != f->first) {
changedest(f->first, h, 1);
bexcise(f);
}
else {
f->link = o;
o = f;
}
f = t;
}
s->ents = o;
}
else {
o = nil;
p = nil;
while(f != nil) {
t = f->link;
if((f->flags & (Bpre|Bpin)) != 0 || (f->last->link == R)) {
f->link = p;
p = f;
}
else {
f->link = o;
o = f;
}
f = t;
}
if(o == nil) {
diag(Z, "all Bpre");
return;
}
if(p == nil) {
p = o;
o = p->link;
p->link = nil;
s->ents = p;
}
else
s->ents = p;
h = p->first;
// oblit o list repl with jmp to h
while(o != nil) {
changedest(o->first, h, 1);
bexcise(o);
o = o->link;
}
bbsrecalc(s);
}
}
static void
iterate(void)
{
BBset *s;
BB *b, *t;
heapn = 0;
for(;;) {
for(b = wounded; b != nil; b = t) {
t = b->link;
enterbb(b);
}
wounded = nil;
for(s = recalc; s != nil; s = s->link)
calcdamage(s);
recalc = nil;
if(heapn == 0)
return;
s = heap[1];
heapremove(s);
process(s);
}
}
static void
cleanup(void)
{
int i;
BB *l, *n;
BBset *b, *t;
for(i = 0; i < BBHASH; i++) {
b = bbhash[i];
bbhash[i] = nil;
while(b != nil) {
t = b->next;
bsfree(b);
b = t;
}
}
for(i = 0; i < bcount; i++)
bfree(ordered[i]);
for(l = bbaux; l != nil; l = n) {
n = l->aux;
bfree(l);
}
bbaux = nil;
}
static void
prreg(Reg *r)
{
Prog *p;
p = r->prog;
if(p->to.type == D_BRANCH)
p->to.offset = r->s2->rpo;
print("%ld:%P\tr %lX ", r->rpo, r->prog, r->regu);
print("p1 %ld p2 %ld p2l %ld s1 %ld s2 %ld link %ld",
Rn(r->p1), Rn(r->p2), Rn(r->p2link),
Rn(r->s1), Rn(r->s2), Rn(r->link));
if(!r->active)
print(" d");
// print(" %p %p\n", r->prog, r->prog->link);
print("\n");
}
static void prfunc(char*);
static void
checkr(int d)
{
Prog *p;
Reg *r, *t;
for(r = firstr; r->link != R; r = r->link) {
for(p = r->prog->link; p != P && p != r->link->prog; p = p->link)
;
if(p == P) {
print("%ld: bad prog link\n", r->rpo);
if(d)
prfunc(nil);
abort();
}
if(r->s1 != R && (r->s1 != r->link || r->link->p1 != r)) {
print("%ld: bad s1 p1\n", r->rpo);
if(d)
prfunc(nil);
abort();
}
if(r->s2 != R && r->s2->p2 == nil) {
print("%ld: no p2 for s2\n", r->rpo);
if(d)
prfunc(nil);
abort();
}
if(r->p2 != R) {
t = r->p2->s2;
while(t != r) {
t = t->p2link;
if(t == R) {
print("%ld: bad s2 for p2\n", r->rpo);
if(d)
prfunc(nil);
abort();
}
}
}
}
}
static void
prfunc(char *s)
{
Reg *r;
if(s != nil)
print("%s structure %s\n", s, firstr->prog->from.sym->name);
for(r = firstr; r != R; r = r->link)
prreg(r);
if(s != nil) {
print("end\n");
checkr(0);
}
}
/* find p in r's list and replace with l */
static void
adjprog(Reg *r, Prog *p, Prog *l)
{
Prog *t, **n;
for(n = &r->prog->link; (t = *n) != nil; n = &t->link) {
if(t == p) {
*n = l;
return;
}
}
print("adjprog botch\n");
abort();
}
static void
jumptojump(void)
{
Reg *r;
for(r = firstr; r != R; r = r->link) {
if(r->prog->as == AJMP && r->p2 != R && r->s2 != r) {
if(bdebug)
print("jump as dest %ld -> %ld\n", r->rpo, r->s2->rpo);
changedest(r, r->s2, 0);
bchange++;
}
}
}
/* drag a tail to replace a jump. seems to be a bad idea. */
static void
rearrange(void)
{
int i;
Reg *j, *t;
BB *b, *p, *s;
for(i = 0; i < bcount; i++) {
b = ordered[i];
if(b->flags & Bdel)
continue;
j = b->last;
if(j->prog->as == AJMP && j->s2->p1 == R) {
t = j->s2;
if(t == b->first)
continue;
s = findset(t->rpo);
if(s == nil) {
diag(Z, "no self");
continue;
}
if(s == ordered[0])
continue;
if(s->flags & Bdel)
continue;
if(s->last->link == R)
continue;
if(bdebug)
print("drag %ld to %ld\n", t->rpo, j->rpo);
p = findset(t->rpo - 1);
if(p == nil) {
diag(Z, "no predec");
continue;
}
if(p->last->link != t) {
diag(Z, "bad predec %ld %ld", p->last->rpo, t->rpo);
continue;
}
/* poison everything in sight */
b->flags |= Bdel;
s->flags |= Bdel;
findset(j->link->rpo)->flags |= Bdel;
findset(s->last->link->rpo)->flags |= Bdel;
/* remove */
adjprog(p->last, t->prog, s->last->link->prog);
p->last->link = s->last->link;
/* fix tail */
adjprog(s->last, s->last->link->prog, j->link->prog);
s->last->link = j->link;
/* fix head */
adjprog(j, j->link->prog, t->prog);
j->link = t;
/* nop the jump */
j->prog->as = ANOP;
j->prog->to.type = D_NONE;
j->s2 = nil;
j->link->p2 = delset(j, j->link->p2);
j->s1 = t;
t->p1 = j;
if(bcheck)
checkr(1);
bchange++;
}
}
}
void
jumptodot(void)
{
Reg *r;
for(r = firstr; r != R; r = r->link) {
if(r->prog->as == AJMP && r->s2 == r->link) {
if(debug['v'])
print("jump to next %ld\n", r->rpo);
r->prog->as = ANOP;
r->prog->to.type = D_NONE;
r->s2 = nil;
r->link->p2 = delset(r, r->link->p2);
findset(r->rpo)->flags |= Bdel;
findset(r->link->rpo)->flags |= Bdel;
bchange++;
}
}
}
void
comtarg(void)
{
int n;
BB *b, *c;
Reg *r, *l, *p, *t;
loop:
bchange = 0;
/* excise NOPS because they just get in the way */
/* some have p2 because they are excised labelled moves */
if(debug['v']) {
n = 0;
for(r = firstr; r != R; r = r->link)
r->rpo = n++;
prfunc("prenop");
}
r = firstr;
l = r->link;
while(l != R) {
if(l->prog->as == ANOP) {
t = l->p1;
p = l->p2;
if(dbg) print("nop %ld [", l->rpo);
if(dbg) printbl(p);
for(;;) {
adjprog(r, l->prog, l->prog->link);
r->link = l->link;
l->link = freer;
freer = l;
l = r->link;
if(l->prog->as != ANOP)
break;
if(dbg) print("] %ld [", l->rpo);
if(dbg) printbl(l->p2);
if(p == R)
p = l->p2;
else if(l->p2 != nil)
appset(l->p2, p);
}
if(dbg) print("] %ld [", l->rpo);
if(dbg) printbl(l->p2);
if(p != R) {
redest(p, l);
if(l->p2 != R)
appset(p, l->p2);
else
l->p2 = p;
}
if(dbg) print("] -> [");
if(dbg) printbl(l->p2);
if(dbg) print("]\n");
if(r->s1 != R)
r->s1 = l;
l->p1 = t;
}
r = l;
l = r->link;
}
n = 0;
for(r = firstr; r != R; r = r->link)
r->rpo = n++;
if(debug['v'])
prfunc("input");
firstbb = nil;
lastbb = nil;
if(debug['v'])
print("bbstart\n");
n = 0;
r = firstr;
do {
b = bba();
b->first = r;
for(;;) {
l = r;
r = r->link;
switch(l->prog->as) {
case ARET:
case AJMP:
case AIRETL:
goto out;
}
if(r->p2 != R)
break;
}
out:
b->last = l;
if(lastbb == nil)
firstbb = b;
else
lastbb->link = b;
lastbb = b;
if(bdebug)
print("BB %ld %ld\n", b->first->rpo, b->last->rpo);
n++;
} while(r != R);
if(debug['v'])
print("end\n");
if(n > bsize) {
bsize = n * 3 / 2;
if(bsize < BBINIT)
bsize = BBINIT;
ordered = alloc(bsize * sizeof(*ordered));
heap = alloc((bsize + 1) * sizeof(*ordered));
}
if(debug['v'])
print("preprocstart\n");
n = 0;
for(b = firstbb; b != nil; b = c) {
c = b->link;
preproc(b, n++);
}
if(debug['v'])
print("end\n");
bcount = n;
jumptojump();
if(debug['v'])
print("iteratestart\n");
iterate();
//checktails();
if(debug['v'])
print("end\n");
if(debug['v'])
print("extrastart\n");
jumptodot();
// rearrange();
if(debug['v'])
print("end\n");
cleanup();
if(bballoc || bbsalloc)
diag(Z, "bballoc %d %d", bballoc, bbsalloc);
if(debug['v'])
prfunc("output");
if(1 && bchange)
goto loop;
}