cmd/internal/gc: change Naddr to take a *Addr to fill in

This allows gins to let Naddr fill in p.From and p.To directly,
avoiding the zeroing and copying of a temporary.

Change-Id: I96d120afe266e68f94d5e82b00886bf6bd458f85
Reviewed-on: https://go-review.googlesource.com/7742Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>

src/cmd/5g/ggen.go

@@ -78,7 +78,7 @@ func zerorange(p *obj.Prog, frame int64, lo int64, hi int64, r0 *uint32) *obj.Pr
 		p.Reg = arm.REGSP
 		p = appendpp(p, obj.ADUFFZERO, obj.TYPE_NONE, 0, 0, obj.TYPE_MEM, 0, 0)
 		f := gc.Sysfunc("duffzero")
-		p.To = gc.Naddr(f)
+		gc.Naddr(&p.To, f)
 		gc.Afunclit(&p.To, f)
 		p.To.Offset = 4 * (128 - cnt/int64(gc.Widthptr))
 	} else {

src/cmd/5g/gsubr.go

@@ -842,22 +842,11 @@ func gins(as int, f *gc.Node, t *gc.Node) *obj.Prog {
 	//		constnode.vconst = v;
 	//		idx.reg = nod.reg;
 	//		regfree(&nod);
-	var af obj.Addr
 
-	var at obj.Addr
-	if f != nil {
-		af = gc.Naddr(f)
-	}
-	if t != nil {
-		at = gc.Naddr(t)
-	}
 	p := gc.Prog(as)
-	if f != nil {
-		p.From = af
-	}
-	if t != nil {
-		p.To = at
-	}
+	gc.Naddr(&p.From, f)
+	gc.Naddr(&p.To, t)
+
 	if gc.Debug['g'] != 0 {
 		fmt.Printf("%v\n", p)
 	}
@@ -869,8 +858,7 @@ func gins(as int, f *gc.Node, t *gc.Node) *obj.Prog {
  */
 func raddr(n *gc.Node, p *obj.Prog) {
 	var a obj.Addr
-
-	a = gc.Naddr(n)
+	gc.Naddr(&a, n)
 	if a.Type != obj.TYPE_REG {
 		if n != nil {
 			gc.Fatal("bad in raddr: %v", gc.Oconv(int(n.Op), 0))
@@ -1306,7 +1294,7 @@ func sudoaddable(as int, n *gc.Node, a *obj.Addr, w *int) bool {
 		reg1 := &clean[cleani-2]
 		reg.Op = gc.OEMPTY
 		reg1.Op = gc.OEMPTY
-		*a = gc.Naddr(n)
+		gc.Naddr(a, n)
 		return true
 
 	case gc.ODOT,
@@ -1330,7 +1318,7 @@ func sudoaddable(as int, n *gc.Node, a *obj.Addr, w *int) bool {
 
 			n1.Type = n.Type
 			n1.Xoffset += oary[0]
-			*a = gc.Naddr(&n1)
+			gc.Naddr(a, &n1)
 			return true
 		}
 
@@ -1358,7 +1346,7 @@ func sudoaddable(as int, n *gc.Node, a *obj.Addr, w *int) bool {
 		a.Type = obj.TYPE_NONE
 		a.Name = obj.NAME_NONE
 		n1.Type = n.Type
-		*a = gc.Naddr(&n1)
+		gc.Naddr(a, &n1)
 		return true
 
 	case gc.OINDEX:

src/cmd/6g/gsubr.go

@@ -746,21 +746,10 @@ func gins(as int, f *gc.Node, t *gc.Node) *obj.Prog {
 		}
 	}
 
-	var af obj.Addr
-	if f != nil {
-		af = gc.Naddr(f)
-	}
-	var at obj.Addr
-	if t != nil {
-		at = gc.Naddr(t)
-	}
 	p := gc.Prog(as)
-	if f != nil {
-		p.From = af
-	}
-	if t != nil {
-		p.To = at
-	}
+	gc.Naddr(&p.From, f)
+	gc.Naddr(&p.To, t)
+
 	if gc.Debug['g'] != 0 {
 		fmt.Printf("%v\n", p)
 	}
@@ -780,10 +769,10 @@ func gins(as int, f *gc.Node, t *gc.Node) *obj.Prog {
 		w = 8
 	}
 
-	if w != 0 && ((f != nil && af.Width < int64(w)) || (t != nil && at.Width > int64(w))) {
+	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, af.Width, at.Width)
+		gc.Fatal("bad width: %v (%d, %d)\n", p, p.From.Width, p.To.Width)
 	}
 
 	if p.To.Type == obj.TYPE_ADDR && w > 0 {
@@ -1405,7 +1394,7 @@ func sudoaddable(as int, n *gc.Node, a *obj.Addr) bool {
 		reg1 := &clean[cleani-2]
 		reg.Op = gc.OEMPTY
 		reg1.Op = gc.OEMPTY
-		*a = gc.Naddr(n)
+		gc.Naddr(a, n)
 		return true
 
 	case gc.ODOT,
@@ -1429,7 +1418,7 @@ func sudoaddable(as int, n *gc.Node, a *obj.Addr) bool {
 
 			n1.Type = n.Type
 			n1.Xoffset += oary[0]
-			*a = gc.Naddr(&n1)
+			gc.Naddr(a, &n1)
 			return true
 		}
 
@@ -1457,7 +1446,7 @@ func sudoaddable(as int, n *gc.Node, a *obj.Addr) bool {
 		a.Type = obj.TYPE_NONE
 		a.Index = obj.TYPE_NONE
 		fixlargeoffset(&n1)
-		*a = gc.Naddr(&n1)
+		gc.Naddr(a, &n1)
 		return true
 
 	case gc.OINDEX:

src/cmd/7g/ggen.go

@@ -77,7 +77,7 @@ func zerorange(p *obj.Prog, frame int64, lo int64, hi int64) *obj.Prog {
 		p.Reg = arm64.REGRT1
 		p = appendpp(p, obj.ADUFFZERO, obj.TYPE_NONE, 0, 0, obj.TYPE_MEM, 0, 0)
 		f := gc.Sysfunc("duffzero")
-		p.To = gc.Naddr(f)
+		gc.Naddr(&p.To, f)
 		gc.Afunclit(&p.To, f)
 		p.To.Offset = 4 * (128 - cnt/int64(gc.Widthptr))
 	} else {

src/cmd/7g/gsubr.go

@@ -615,22 +615,10 @@ func gins(as int, f *gc.Node, t *gc.Node) *obj.Prog {
 	// TODO(austin): Add self-move test like in 6g (but be careful
 	// of truncation moves)
 
-	af := obj.Addr(obj.Addr{})
+	p := gc.Prog(as)
+	gc.Naddr(&p.From, f)
+	gc.Naddr(&p.To, t)
 
-	at := obj.Addr(obj.Addr{})
-	if f != nil {
-		af = gc.Naddr(f)
-	}
-	if t != nil {
-		at = gc.Naddr(t)
-	}
-	p := (*obj.Prog)(gc.Prog(as))
-	if f != nil {
-		p.From = af
-	}
-	if t != nil {
-		p.To = at
-	}
 	if gc.Debug['g'] != 0 {
 		fmt.Printf("%v\n", p)
 	}
@@ -650,16 +638,16 @@ func gins(as int, f *gc.Node, t *gc.Node) *obj.Prog {
 		w = 4
 
 	case arm64.AMOVD:
-		if af.Type == obj.TYPE_CONST || af.Type == obj.TYPE_ADDR {
+		if p.From.Type == obj.TYPE_CONST || p.From.Type == obj.TYPE_ADDR {
 			break
 		}
 		w = 8
 	}
 
-	if w != 0 && ((f != nil && af.Width < int64(w)) || (t != nil && at.Type != obj.TYPE_REG && at.Width > int64(w))) {
+	if w != 0 && ((f != nil && p.From.Width < int64(w)) || (t != nil && p.To.Type != obj.TYPE_REG && p.To.Width > int64(w))) {
 		gc.Dump("f", f)
 		gc.Dump("t", t)
-		gc.Fatal("bad width: %v (%d, %d)\n", p, af.Width, at.Width)
+		gc.Fatal("bad width: %v (%d, %d)\n", p, p.From.Width, p.To.Width)
 	}
 
 	return p
@@ -690,7 +678,7 @@ func fixlargeoffset(n *gc.Node) {
 func raddr(n *gc.Node, p *obj.Prog) {
 	var a obj.Addr
 
-	a = gc.Naddr(n)
+	gc.Naddr(&a, n)
 	if a.Type != obj.TYPE_REG {
 		if n != nil {
 			gc.Fatal("bad in raddr: %v", gc.Oconv(int(n.Op), 0))

src/cmd/8g/gsubr.go

@@ -1844,21 +1844,10 @@ func gins(as int, f *gc.Node, t *gc.Node) *obj.Prog {
 		}
 	}
 
-	var af obj.Addr
-	var at obj.Addr
-	if f != nil {
-		af = gc.Naddr(f)
-	}
-	if t != nil {
-		at = gc.Naddr(t)
-	}
 	p := gc.Prog(as)
-	if f != nil {
-		p.From = af
-	}
-	if t != nil {
-		p.To = at
-	}
+	gc.Naddr(&p.From, f)
+	gc.Naddr(&p.To, t)
+
 	if gc.Debug['g'] != 0 {
 		fmt.Printf("%v\n", p)
 	}
@@ -1875,10 +1864,10 @@ func gins(as int, f *gc.Node, t *gc.Node) *obj.Prog {
 		w = 4
 	}
 
-	if true && w != 0 && f != nil && (af.Width > int64(w) || at.Width > int64(w)) {
+	if true && w != 0 && f != nil && (p.From.Width > int64(w) || p.To.Width > int64(w)) {
 		gc.Dump("bad width from:", f)
 		gc.Dump("bad width to:", t)
-		gc.Fatal("bad width: %v (%d, %d)\n", p, af.Width, at.Width)
+		gc.Fatal("bad width: %v (%d, %d)\n", p, p.From.Width, p.To.Width)
 	}
 
 	if p.To.Type == obj.TYPE_ADDR && w > 0 {

src/cmd/9g/ggen.go

@@ -76,7 +76,7 @@ func zerorange(p *obj.Prog, frame int64, lo int64, hi int64) *obj.Prog {
 		p.Reg = ppc64.REGSP
 		p = appendpp(p, obj.ADUFFZERO, obj.TYPE_NONE, 0, 0, obj.TYPE_MEM, 0, 0)
 		f := gc.Sysfunc("duffzero")
-		p.To = gc.Naddr(f)
+		gc.Naddr(&p.To, f)
 		gc.Afunclit(&p.To, f)
 		p.To.Offset = 4 * (128 - cnt/int64(gc.Widthptr))
 	} else {

src/cmd/9g/gsubr.go

@@ -696,22 +696,10 @@ func gins(as int, f *gc.Node, t *gc.Node) *obj.Prog {
 	// TODO(austin): Add self-move test like in 6g (but be careful
 	// of truncation moves)
 
-	af := obj.Addr(obj.Addr{})
+	p := gc.Prog(as)
+	gc.Naddr(&p.From, f)
+	gc.Naddr(&p.To, t)
 
-	at := obj.Addr(obj.Addr{})
-	if f != nil {
-		af = gc.Naddr(f)
-	}
-	if t != nil {
-		at = gc.Naddr(t)
-	}
-	p := (*obj.Prog)(gc.Prog(as))
-	if f != nil {
-		p.From = af
-	}
-	if t != nil {
-		p.To = at
-	}
 	if gc.Debug['g'] != 0 {
 		fmt.Printf("%v\n", p)
 	}
@@ -738,16 +726,16 @@ func gins(as int, f *gc.Node, t *gc.Node) *obj.Prog {
 
 	case ppc64.AMOVD,
 		ppc64.AMOVDU:
-		if af.Type == obj.TYPE_CONST || af.Type == obj.TYPE_ADDR {
+		if p.From.Type == obj.TYPE_CONST || p.From.Type == obj.TYPE_ADDR {
 			break
 		}
 		w = 8
 	}
 
-	if w != 0 && ((f != nil && af.Width < int64(w)) || (t != nil && at.Type != obj.TYPE_REG && at.Width > int64(w))) {
+	if w != 0 && ((f != nil && p.From.Width < int64(w)) || (t != nil && p.To.Type != obj.TYPE_REG && p.To.Width > int64(w))) {
 		gc.Dump("f", f)
 		gc.Dump("t", t)
-		gc.Fatal("bad width: %v (%d, %d)\n", p, af.Width, at.Width)
+		gc.Fatal("bad width: %v (%d, %d)\n", p, p.From.Width, p.To.Width)
 	}
 
 	return p

src/cmd/internal/gc/gsubr.go

@@ -273,7 +273,9 @@ func markautoused(p *obj.Prog) {
 	}
 }
 
-func Naddr(n *Node) (a obj.Addr) {
+// Naddr rewrites a to refer to n.
+// It assumes that a is zeroed on entry.
+func Naddr(a *obj.Addr, n *Node) {
 	if n == nil {
 		return
 	}
@@ -293,7 +295,7 @@ func Naddr(n *Node) (a obj.Addr) {
 	switch n.Op {
 	default:
 		a := a // copy to let escape into Ctxt.Dconv
-		Fatal("naddr: bad %v %v", Oconv(int(n.Op), 0), Ctxt.Dconv(&a))
+		Fatal("naddr: bad %v %v", Oconv(int(n.Op), 0), Ctxt.Dconv(a))
 
 	case OREGISTER:
 		a.Type = obj.TYPE_REG
@@ -337,7 +339,7 @@ func Naddr(n *Node) (a obj.Addr) {
 		a.Offset = n.Xoffset
 
 	case OCFUNC:
-		a = Naddr(n.Left)
+		Naddr(a, n.Left)
 		a.Sym = Linksym(n.Left.Sym)
 
 	case ONAME:
@@ -407,7 +409,7 @@ func Naddr(n *Node) (a obj.Addr) {
 			a.Offset = Mpgetfix(n.Val.U.Xval)
 
 		case CTSTR:
-			datagostring(n.Val.U.Sval, &a)
+			datagostring(n.Val.U.Sval, a)
 
 		case CTBOOL:
 			a.Sym = nil
@@ -421,20 +423,20 @@ func Naddr(n *Node) (a obj.Addr) {
 		}
 
 	case OADDR:
-		a = Naddr(n.Left)
+		Naddr(a, n.Left)
 		a.Etype = uint8(Tptr)
 		if Thearch.Thechar != '5' && Thearch.Thechar != '7' && Thearch.Thechar != '9' { // TODO(rsc): Do this even for arm, ppc64.
 			a.Width = int64(Widthptr)
 		}
 		if a.Type != obj.TYPE_MEM {
 			a := a // copy to let escape into Ctxt.Dconv
-			Fatal("naddr: OADDR %v (from %v)", Ctxt.Dconv(&a), Oconv(int(n.Left.Op), 0))
+			Fatal("naddr: OADDR %v (from %v)", Ctxt.Dconv(a), Oconv(int(n.Left.Op), 0))
 		}
 		a.Type = obj.TYPE_ADDR
 
 		// itable of interface value
 	case OITAB:
-		a = Naddr(n.Left)
+		Naddr(a, n.Left)
 
 		if a.Type == obj.TYPE_CONST && a.Offset == 0 {
 			break // itab(nil)
@@ -444,7 +446,7 @@ func Naddr(n *Node) (a obj.Addr) {
 
 		// pointer in a string or slice
 	case OSPTR:
-		a = Naddr(n.Left)
+		Naddr(a, n.Left)
 
 		if a.Type == obj.TYPE_CONST && a.Offset == 0 {
 			break // ptr(nil)
@@ -455,7 +457,7 @@ func Naddr(n *Node) (a obj.Addr) {
 
 		// len of string or slice
 	case OLEN:
-		a = Naddr(n.Left)
+		Naddr(a, n.Left)
 
 		if a.Type == obj.TYPE_CONST && a.Offset == 0 {
 			break // len(nil)
@@ -471,7 +473,7 @@ func Naddr(n *Node) (a obj.Addr) {
 
 		// cap of string or slice
 	case OCAP:
-		a = Naddr(n.Left)
+		Naddr(a, n.Left)
 
 		if a.Type == obj.TYPE_CONST && a.Offset == 0 {
 			break // cap(nil)

src/cmd/internal/gc/plive.go

@@ -1054,8 +1054,8 @@ func newpcdataprog(prog *obj.Prog, index int32) *obj.Prog {
 	Nodconst(&to, Types[TINT32], int64(index))
 	pcdata := unlinkedprog(obj.APCDATA)
 	pcdata.Lineno = prog.Lineno
-	pcdata.From = Naddr(&from)
-	pcdata.To = Naddr(&to)
+	Naddr(&pcdata.From, &from)
+	Naddr(&pcdata.To, &to)
 	return pcdata
 }