static void
xfol(Prog *p, Prog **last)
{
Prog *q;
int i;
enum as a;
loop:
if(p == P)
return;
if(p->as == AJMP)
if((q = p->pcond) != P && q->as != ATEXT) {
/* mark instruction as done and continue layout at target of jump */
p->mark = 1;
p = q;
if(p->mark == 0)
goto loop;
}
if(p->mark) {
/*
* p goes here, but already used it elsewhere.
* copy up to 4 instructions or else branch to other copy.
*/
for(i=0,q=p; i<4; i++,q=q->link) {
if(q == P)
break;
if(q == *last)
break;
a = q->as;
if(a == ANOP) {
i--;
continue;
}
if(nofollow(a) || pushpop(a))
break; // NOTE(rsc): arm does goto copy
if(q->pcond == P || q->pcond->mark)
continue;
if(a == ACALL || a == ALOOP)
continue;
for(;;) {
if(p->as == ANOP) {
p = p->link;
continue;
}
q = copyp(p);
p = p->link;
q->mark = 1;
(*last)->link = q;
*last = q;
if(q->as != a || q->pcond == P || q->pcond->mark)
continue;
q->as = relinv(q->as);
p = q->pcond;
q->pcond = q->link;
q->link = p;
xfol(q->link, last);
p = q->link;
if(p->mark)
return;
goto loop;
}
} /* */
q = prg();
q->as = AJMP;
q->line = p->line;
q->to.type = D_BRANCH;
q->to.offset = p->pc;
q->pcond = p;
p = q;
}
/* emit p */
p->mark = 1;
(*last)->link = p;
*last = p;
a = p->as;
/* continue loop with what comes after p */
if(nofollow(a))
return;
if(p->pcond != P && a != ACALL) {
/*
* some kind of conditional branch.
* recurse to follow one path.
* continue loop on the other.
*/
q = brchain(p->link);
if(q != P && q->mark)
if(a != ALOOP) {
p->as = relinv(a);
p->link = p->pcond;
p->pcond = q;
}
xfol(p->link, last);
q = brchain(p->pcond);
if(q->mark) {
p->pcond = q;
return;
}
p = q;
goto loop;
}
p = p->link;
goto loop;
}
void
xfol(Prog *p)
{
Prog *q;
int i;
enum as a;
loop:
if(p == P)
return;
if(p->as == ATEXT)
curtext = p;
if(p->as == AJMP)
if((q = p->pcond) != P) {
p->mark = 1;
p = q;
if(p->mark == 0)
goto loop;
}
if(p->mark) {
/* copy up to 4 instructions to avoid branch */
for(i=0,q=p; i<4; i++,q=q->link) {
if(q == P)
break;
if(q == lastp)
break;
a = q->as;
if(a == ANOP) {
i--;
continue;
}
switch(a) {
case AJMP:
case ARET:
case AIRETL:
case APUSHL:
case APUSHFL:
case APUSHW:
case APUSHFW:
case APOPL:
case APOPFL:
case APOPW:
case APOPFW:
goto brk;
}
if(q->pcond == P || q->pcond->mark)
continue;
if(a == ACALL || a == ALOOP)
continue;
for(;;) {
if(p->as == ANOP) {
p = p->link;
continue;
}
q = copyp(p);
p = p->link;
q->mark = 1;
lastp->link = q;
lastp = q;
if(q->as != a || q->pcond == P || q->pcond->mark)
continue;
q->as = relinv(q->as);
p = q->pcond;
q->pcond = q->link;
q->link = p;
xfol(q->link);
p = q->link;
if(p->mark)
return;
goto loop;
}
} /* */
brk:
;
q = prg();
q->as = AJMP;
q->line = p->line;
q->to.type = D_BRANCH;
q->to.offset = p->pc;
q->pcond = p;
p = q;
}
p->mark = 1;
lastp->link = p;
lastp = p;
a = p->as;
if(a == AJMP || a == ARET || a == AIRETL)
return;
if(p->pcond != P)
if(a != ACALL) {
q = brchain(p->link);
if(q != P && q->mark)
if(a != ALOOP) {
p->as = relinv(a);
p->link = p->pcond;
p->pcond = q;
}
xfol(p->link);
q = brchain(p->pcond);
if(q->mark) {
p->pcond = q;
return;
}
p = q;
goto loop;
}
p = p->link;
goto loop;
}
void
xfol(Prog *p)
{
Prog *q, *r;
int a, i;
loop:
if(p == P)
return;
setarch(p);
a = p->as;
if(a == ATEXT)
curtext = p;
if(!curtext->from.sym->reachable) {
p = p->cond;
goto loop;
}
if(a == AB) {
q = p->cond;
if(q != P) {
p->mark |= FOLL;
p = q;
if(!(p->mark & FOLL))
goto loop;
}
}
if(p->mark & FOLL) {
for(i=0,q=p; i<4; i++,q=q->link) {
if(q == lastp)
break;
a = q->as;
if(a == ANOP) {
i--;
continue;
}
if(a == AB || (a == ARET && q->scond == 14) || a == ARFE)
goto copy;
if(!q->cond || (q->cond->mark&FOLL))
continue;
if(a != ABEQ && a != ABNE)
continue;
copy:
for(;;) {
r = prg();
*r = *p;
if(!(r->mark&FOLL))
print("cant happen 1\n");
r->mark |= FOLL;
if(p != q) {
p = p->link;
lastp->link = r;
lastp = r;
continue;
}
lastp->link = r;
lastp = r;
if(a == AB || (a == ARET && q->scond == 14) || a == ARFE)
return;
r->as = ABNE;
if(a == ABNE)
r->as = ABEQ;
r->cond = p->link;
r->link = p->cond;
if(!(r->link->mark&FOLL))
xfol(r->link);
if(!(r->cond->mark&FOLL))
print("cant happen 2\n");
return;
}
}
a = AB;
q = prg();
q->as = a;
q->line = p->line;
q->to.type = D_BRANCH;
q->to.offset = p->pc;
q->cond = p;
p = q;
}
p->mark |= FOLL;
lastp->link = p;
lastp = p;
if(a == AB || (a == ARET && p->scond == 14) || a == ARFE){
return;
}
if(p->cond != P)
if(a != ABL && a != ABX && p->link != P) {
q = brchain(p->link);
if(a != ATEXT && a != ABCASE)
if(q != P && (q->mark&FOLL)) {
p->as = relinv(a);
p->link = p->cond;
p->cond = q;
}
xfol(p->link);
q = brchain(p->cond);
if(q == P)
q = p->cond;
if(q->mark&FOLL) {
p->cond = q;
return;
}
p = q;
goto loop;
}
p = p->link;
goto loop;
}
static void
xfol(Prog *p, Prog **last)
{
Prog *q, *r;
int a, i;
loop:
if(p == P)
return;
a = p->as;
if(a == AB) {
q = p->cond;
if(q != P && q->as != ATEXT) {
p->mark |= FOLL;
p = q;
if(!(p->mark & FOLL))
goto loop;
}
}
if(p->mark & FOLL) {
for(i=0,q=p; i<4; i++,q=q->link) {
if(q == *last || q == nil)
break;
a = q->as;
if(a == ANOP) {
i--;
continue;
}
if(a == AB || (a == ARET && q->scond == 14) || a == ARFE || a == AUNDEF)
goto copy;
if(q->cond == P || (q->cond->mark&FOLL))
continue;
if(a != ABEQ && a != ABNE)
continue;
copy:
for(;;) {
r = prg();
*r = *p;
if(!(r->mark&FOLL))
print("can't happen 1\n");
r->mark |= FOLL;
if(p != q) {
p = p->link;
(*last)->link = r;
*last = r;
continue;
}
(*last)->link = r;
*last = r;
if(a == AB || (a == ARET && q->scond == 14) || a == ARFE || a == AUNDEF)
return;
r->as = ABNE;
if(a == ABNE)
r->as = ABEQ;
r->cond = p->link;
r->link = p->cond;
if(!(r->link->mark&FOLL))
xfol(r->link, last);
if(!(r->cond->mark&FOLL))
print("can't happen 2\n");
return;
}
}
a = AB;
q = prg();
q->as = a;
q->line = p->line;
q->to.type = D_BRANCH;
q->to.offset = p->pc;
q->cond = p;
p = q;
}
p->mark |= FOLL;
(*last)->link = p;
*last = p;
if(a == AB || (a == ARET && p->scond == 14) || a == ARFE || a == AUNDEF){
return;
}
if(p->cond != P)
if(a != ABL && a != ABX && p->link != P) {
q = brchain(p->link);
if(a != ATEXT && a != ABCASE)
if(q != P && (q->mark&FOLL)) {
p->as = relinv(a);
p->link = p->cond;
p->cond = q;
}
xfol(p->link, last);
q = brchain(p->cond);
if(q == P)
q = p->cond;
if(q->mark&FOLL) {
p->cond = q;
return;
}
p = q;
goto loop;
}
p = p->link;
goto loop;
}