/*
* generate one instruction:
* as f, t
*/
func gins(as int, f *gc.Node, t *gc.Node) *obj.Prog {
// Node nod;
// if(f != N && f->op == OINDEX) {
// gc.Regalloc(&nod, ®node, Z);
// v = constnode.vconst;
// gc.Cgen(f->right, &nod);
// constnode.vconst = v;
// idx.reg = nod.reg;
// gc.Regfree(&nod);
// }
// if(t != N && t->op == OINDEX) {
// gc.Regalloc(&nod, ®node, Z);
// v = constnode.vconst;
// gc.Cgen(t->right, &nod);
// constnode.vconst = v;
// idx.reg = nod.reg;
// gc.Regfree(&nod);
// }
if f != nil && f.Op == gc.OADDR && (as == x86.AMOVL || as == x86.AMOVQ) {
// Turn MOVL $xxx into LEAL xxx.
// These should be equivalent but most of the backend
// only expects to see LEAL, because that's what we had
// historically generated. Various hidden assumptions are baked in by now.
if as == x86.AMOVL {
as = x86.ALEAL
} else {
as = x86.ALEAQ
}
f = f.Left
}
switch as {
case x86.AMOVB,
x86.AMOVW,
x86.AMOVL,
x86.AMOVQ,
x86.AMOVSS,
x86.AMOVSD:
if f != nil && t != nil && samaddr(f, t) {
return nil
}
case x86.ALEAQ:
if f != nil && gc.Isconst(f, gc.CTNIL) {
gc.Fatal("gins LEAQ nil %v", f.Type)
}
}
p := gc.Prog(as)
gc.Naddr(&p.From, f)
gc.Naddr(&p.To, t)
if gc.Debug['g'] != 0 {
fmt.Printf("%v\n", p)
}
w := int32(0)
switch as {
case x86.AMOVB:
w = 1
case x86.AMOVW:
w = 2
case x86.AMOVL:
w = 4
case x86.AMOVQ:
w = 8
}
if w != 0 && ((f != nil && p.From.Width < int64(w)) || (t != nil && p.To.Width > int64(w))) {
gc.Dump("f", f)
gc.Dump("t", t)
gc.Fatal("bad width: %v (%d, %d)\n", p, p.From.Width, p.To.Width)
}
if p.To.Type == obj.TYPE_ADDR && w > 0 {
gc.Fatal("bad use of addr: %v", p)
}
return p
}
/*
* generate code to compute address of n,
* a reference to a (perhaps nested) field inside
* an array or struct.
* return 0 on failure, 1 on success.
* on success, leaves usable address in a.
*
* caller is responsible for calling sudoclean
* after successful sudoaddable,
* to release the register used for a.
*/
func sudoaddable(as int, n *gc.Node, a *obj.Addr) bool {
if n.Type == nil {
return false
}
*a = obj.Addr{}
switch n.Op {
case gc.OLITERAL:
if !gc.Isconst(n, gc.CTINT) {
break
}
v := gc.Mpgetfix(n.Val.U.Xval)
if v >= 32000 || v <= -32000 {
break
}
switch as {
default:
return false
case x86.AADDB,
x86.AADDW,
x86.AADDL,
x86.AADDQ,
x86.ASUBB,
x86.ASUBW,
x86.ASUBL,
x86.ASUBQ,
x86.AANDB,
x86.AANDW,
x86.AANDL,
x86.AANDQ,
x86.AORB,
x86.AORW,
x86.AORL,
x86.AORQ,
x86.AXORB,
x86.AXORW,
x86.AXORL,
x86.AXORQ,
x86.AINCB,
x86.AINCW,
x86.AINCL,
x86.AINCQ,
x86.ADECB,
x86.ADECW,
x86.ADECL,
x86.ADECQ,
x86.AMOVB,
x86.AMOVW,
x86.AMOVL,
x86.AMOVQ:
break
}
cleani += 2
reg := &clean[cleani-1]
reg1 := &clean[cleani-2]
reg.Op = gc.OEMPTY
reg1.Op = gc.OEMPTY
gc.Naddr(a, n)
return true
case gc.ODOT,
gc.ODOTPTR:
cleani += 2
reg := &clean[cleani-1]
reg1 := &clean[cleani-2]
reg.Op = gc.OEMPTY
reg1.Op = gc.OEMPTY
var nn *gc.Node
var oary [10]int64
o := gc.Dotoffset(n, oary[:], &nn)
if nn == nil {
sudoclean()
return false
}
if nn.Addable && o == 1 && oary[0] >= 0 {
// directly addressable set of DOTs
n1 := *nn
n1.Type = n.Type
n1.Xoffset += oary[0]
gc.Naddr(a, &n1)
return true
}
gc.Regalloc(reg, gc.Types[gc.Tptr], nil)
n1 := *reg
n1.Op = gc.OINDREG
if oary[0] >= 0 {
gc.Agen(nn, reg)
n1.Xoffset = oary[0]
} else {
gc.Cgen(nn, reg)
gc.Cgen_checknil(reg)
n1.Xoffset = -(oary[0] + 1)
}
for i := 1; i < o; i++ {
if oary[i] >= 0 {
gc.Fatal("can't happen")
}
gins(movptr, &n1, reg)
gc.Cgen_checknil(reg)
n1.Xoffset = -(oary[i] + 1)
}
a.Type = obj.TYPE_NONE
a.Index = obj.TYPE_NONE
gc.Fixlargeoffset(&n1)
gc.Naddr(a, &n1)
return true
case gc.OINDEX:
return false
}
return false
}
