ref: 6c2f8fd5e4f0e0be44495a5526930fa3760cd87e
dir: /utils/0c/sgen.c/
#include "gc.h"
void
codgen(Node *n, Node *nn)
{
Prog *sp;
Node *n1, nod, nod1;
cursafe = 0;
curarg = 0;
maxargsafe = 0;
/*
* isolate name
*/
for(n1 = nn;; n1 = n1->left) {
if(n1 == Z) {
diag(nn, "cant find function name");
return;
}
if(n1->op == ONAME)
break;
}
nearln = nn->lineno;
gpseudo(ATEXT, n1->sym, nodconst(stkoff));
sp = p;
/*
* isolate first argument
*/
if(REGARG) {
if(typesu[thisfn->link->etype]) {
nod1 = *nodret->left;
nodreg(&nod, &nod1, REGARG);
gopcode(OAS, &nod, Z, &nod1);
} else
if(firstarg && typechlp[firstargtype->etype]) {
nod1 = *nodret->left;
nod1.sym = firstarg;
nod1.type = firstargtype;
nod1.xoffset = align(0, firstargtype, Aarg1);
nod1.etype = firstargtype->etype;
nodreg(&nod, &nod1, REGARG);
gopcode(OAS, &nod, Z, &nod1);
}
}
retok = 0;
gen(n);
if(!retok)
if(thisfn->link->etype != TVOID)
warn(Z, "no return at end of function: %s", n1->sym->name);
noretval(3);
gbranch(ORETURN);
if(!debug['N'] || debug['R'] || debug['P'])
regopt(sp);
sp->to.offset += maxargsafe;
}
void
gen(Node *n)
{
Node *l, nod;
Prog *sp, *spc, *spb;
Case *cn;
long sbc, scc;
int o;
loop:
if(n == Z)
return;
nearln = n->lineno;
o = n->op;
if(debug['G'])
if(o != OLIST)
print("%L %O\n", nearln, o);
retok = 0;
switch(o) {
default:
complex(n);
cgen(n, Z);
break;
case OLIST:
gen(n->left);
rloop:
n = n->right;
goto loop;
case ORETURN:
retok = 1;
complex(n);
if(n->type == T)
break;
l = n->left;
if(l == Z) {
noretval(3);
gbranch(ORETURN);
break;
}
if(typesu[n->type->etype]) {
sugen(l, nodret, n->type->width);
noretval(3);
gbranch(ORETURN);
break;
}
regret(&nod, n);
cgen(l, &nod);
regfree(&nod);
if(typefd[n->type->etype])
noretval(1);
else
noretval(2);
gbranch(ORETURN);
break;
case OLABEL:
l = n->left;
if(l) {
l->pc = pc;
if(l->label)
patch(l->label, pc);
}
gbranch(OGOTO); /* prevent self reference in reg */
patch(p, pc);
goto rloop;
case OGOTO:
retok = 1;
n = n->left;
if(n == Z)
return;
if(n->complex == 0) {
diag(Z, "label undefined: %s", n->sym->name);
return;
}
gbranch(OGOTO);
if(n->pc) {
patch(p, n->pc);
return;
}
if(n->label)
patch(n->label, pc-1);
n->label = p;
return;
case OCASE:
l = n->left;
if(cases == C)
diag(n, "case/default outside a switch");
if(l == Z) {
casf();
cases->val = 0;
cases->def = 1;
cases->label = pc;
goto rloop;
}
complex(l);
if(l->type == T)
goto rloop;
if(l->op == OCONST)
if(typechl[l->type->etype]) {
casf();
cases->val = l->vconst;
cases->def = 0;
cases->label = pc;
goto rloop;
}
diag(n, "case expression must be integer constant");
goto rloop;
case OSWITCH:
l = n->left;
complex(l);
if(l->type == T)
break;
if(!typechl[l->type->etype]) {
diag(n, "switch expression must be integer");
break;
}
gbranch(OGOTO); /* entry */
sp = p;
cn = cases;
cases = C;
casf();
sbc = breakpc;
breakpc = pc;
gbranch(OGOTO);
spb = p;
gen(n->right);
gbranch(OGOTO);
patch(p, breakpc);
patch(sp, pc);
regalloc(&nod, l, Z);
nod.type = types[TLONG];
cgen(l, &nod);
doswit(&nod);
regfree(&nod);
patch(spb, pc);
cases = cn;
breakpc = sbc;
break;
case OWHILE:
case ODWHILE:
l = n->left;
gbranch(OGOTO); /* entry */
sp = p;
scc = continpc;
continpc = pc;
gbranch(OGOTO);
spc = p;
sbc = breakpc;
breakpc = pc;
gbranch(OGOTO);
spb = p;
patch(spc, pc);
if(n->op == OWHILE)
patch(sp, pc);
bcomplex(l); /* test */
patch(p, breakpc);
if(n->op == ODWHILE)
patch(sp, pc);
gen(n->right); /* body */
gbranch(OGOTO);
patch(p, continpc);
patch(spb, pc);
continpc = scc;
breakpc = sbc;
break;
case OFOR:
l = n->left;
gen(l->right->left); /* init */
gbranch(OGOTO); /* entry */
sp = p;
scc = continpc;
continpc = pc;
gbranch(OGOTO);
spc = p;
sbc = breakpc;
breakpc = pc;
gbranch(OGOTO);
spb = p;
patch(spc, pc);
gen(l->right->right); /* inc */
patch(sp, pc);
if(l->left != Z) { /* test */
bcomplex(l->left);
patch(p, breakpc);
}
gen(n->right); /* body */
gbranch(OGOTO);
patch(p, continpc);
patch(spb, pc);
continpc = scc;
breakpc = sbc;
break;
case OCONTINUE:
if(continpc < 0) {
diag(n, "continue not in a loop");
break;
}
gbranch(OGOTO);
patch(p, continpc);
break;
case OBREAK:
if(breakpc < 0) {
diag(n, "break not in a loop");
break;
}
gbranch(OGOTO);
patch(p, breakpc);
break;
case OIF:
l = n->left;
bcomplex(l);
sp = p;
if(n->right->left != Z)
gen(n->right->left);
if(n->right->right != Z) {
gbranch(OGOTO);
patch(sp, pc);
sp = p;
gen(n->right->right);
}
patch(sp, pc);
break;
case OSET:
case OUSED:
usedset(n->left, o);
break;
}
}
void
usedset(Node *n, int o)
{
if(n->op == OLIST) {
usedset(n->left, o);
usedset(n->right, o);
return;
}
complex(n);
switch(n->op) {
case OADDR: /* volatile */
gins(ANOP, n, Z);
break;
case ONAME:
if(o == OSET)
gins(ANOP, Z, n);
else
gins(ANOP, n, Z);
break;
}
}
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(r);
if(t >= 0) {
n->op = OASHL;
r->vconst = t;
r->type = types[TINT];
}
t = vlog(l);
if(t >= 0) {
n->op = OASHL;
n->left = r;
n->right = l;
r = l;
l = n->left;
r->vconst = t;
r->type = types[TINT];
}
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];
}
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;
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++;
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;
}
}
void
bcomplex(Node *n)
{
complex(n);
if(n->type != T)
if(tcompat(n, T, n->type, tnot))
n->type = T;
if(n->type != T)
boolgen(n, 1, Z);
else
gbranch(OGOTO);
}