plan9fox/sys/src/cmd/vc/sgen.c
2011-03-30 19:35:09 +03:00

228 lines
3.1 KiB
C

#include "gc.h"
void
noretval(int n)
{
if(n & 1) {
gins(ANOP, Z, Z);
p->to.type = D_REG;
p->to.reg = REGRET;
}
if(n & 2) {
gins(ANOP, Z, Z);
p->to.type = D_FREG;
p->to.reg = FREGRET;
}
}
/*
* calculate addressability as follows
* CONST ==> 20 $value
* NAME ==> 10 name
* REGISTER ==> 11 register
* INDREG ==> 12 *[(reg)+offset]
* &10 ==> 2 $name
* ADD(2, 20) ==> 2 $name+offset
* ADD(3, 20) ==> 3 $(reg)+offset
* &12 ==> 3 $(reg)+offset
* *11 ==> 11 ??
* *2 ==> 10 name
* *3 ==> 12 *(reg)+offset
* calculate complexity (number of registers)
*/
void
xcom(Node *n)
{
Node *l, *r;
int t;
if(n == Z)
return;
l = n->left;
r = n->right;
n->addable = 0;
n->complex = 0;
switch(n->op) {
case OCONST:
n->addable = 20;
return;
case OREGISTER:
n->addable = 11;
return;
case OINDREG:
n->addable = 12;
return;
case ONAME:
n->addable = 10;
return;
case OADDR:
xcom(l);
if(l->addable == 10)
n->addable = 2;
if(l->addable == 12)
n->addable = 3;
break;
case OIND:
xcom(l);
if(l->addable == 11)
n->addable = 12;
if(l->addable == 3)
n->addable = 12;
if(l->addable == 2)
n->addable = 10;
break;
case OADD:
xcom(l);
xcom(r);
if(l->addable == 20) {
if(r->addable == 2)
n->addable = 2;
if(r->addable == 3)
n->addable = 3;
}
if(r->addable == 20) {
if(l->addable == 2)
n->addable = 2;
if(l->addable == 3)
n->addable = 3;
}
break;
case OASLMUL:
case OASMUL:
xcom(l);
xcom(r);
t = vlog(r);
if(t >= 0) {
n->op = OASASHL;
r->vconst = t;
r->type = types[TINT];
}
break;
case OMUL:
case OLMUL:
xcom(l);
xcom(r);
t = vlog(l);
if(t >= 0) {
n->left = r;
n->right = l;
l = r;
r = n->right;
}
t = vlog(r);
if(t >= 0) {
n->op = OASHL;
r->vconst = t;
r->type = types[TINT];
simplifyshift(n);
}
break;
case OASLDIV:
xcom(l);
xcom(r);
t = vlog(r);
if(t >= 0) {
n->op = OASLSHR;
r->vconst = t;
r->type = types[TINT];
}
break;
case OLDIV:
xcom(l);
xcom(r);
t = vlog(r);
if(t >= 0) {
n->op = OLSHR;
r->vconst = t;
r->type = types[TINT];
simplifyshift(n);
}
break;
case OASLMOD:
xcom(l);
xcom(r);
t = vlog(r);
if(t >= 0) {
n->op = OASAND;
r->vconst--;
}
break;
case OLMOD:
xcom(l);
xcom(r);
t = vlog(r);
if(t >= 0) {
n->op = OAND;
r->vconst--;
}
break;
case OLSHR:
case OASHL:
case OASHR:
xcom(l);
xcom(r);
simplifyshift(n);
break;
default:
if(l != Z)
xcom(l);
if(r != Z)
xcom(r);
break;
}
if(n->addable >= 10)
return;
if(l != Z)
n->complex = l->complex;
if(r != Z) {
if(r->complex == n->complex)
n->complex = r->complex+1;
else
if(r->complex > n->complex)
n->complex = r->complex;
}
if(n->complex == 0)
n->complex++;
if(com64(n))
return;
switch(n->op) {
case OFUNC:
n->complex = FNX;
break;
case OADD:
case OXOR:
case OAND:
case OOR:
case OEQ:
case ONE:
/*
* immediate operators, make const on right
*/
if(l->op == OCONST) {
n->left = r;
n->right = l;
}
break;
}
}