cmd/compile: move OCASE/OXCASE Node.Nname into Node.Rlist (type switch variable)

$ sizeof -p cmd/compile/internal/gc Node
Node 168
$

Change-Id: I22bcea8099f308298c9db75c937f35e7fca906f1
Reviewed-on: https://go-review.googlesource.com/10535Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>

src/cmd/compile/internal/gc/esc.go

@@ -604,9 +604,9 @@ func esc(e *EscState, n *Node, up *Node) {
 	if n.Op == OSWITCH && n.Left != nil && n.Left.Op == OTYPESW {
 		for ll := n.List; ll != nil; ll = ll.Next { // cases
 
-			// ll->n->nname is the variable per case
-			if ll.N.Nname != nil {
-				e.nodeEscState(ll.N.Nname).Escloopdepth = e.loopdepth
+			// ll.N.Rlist is the variable per case
+			if ll.N.Rlist != nil {
+				e.nodeEscState(ll.N.Rlist.N).Escloopdepth = e.loopdepth
 			}
 		}
 	}
@@ -677,9 +677,11 @@ func esc(e *EscState, n *Node, up *Node) {
 		if n.Left != nil && n.Left.Op == OTYPESW {
 			for ll := n.List; ll != nil; ll = ll.Next {
 				// cases
-				// ntest->right is the argument of the .(type),
-				// ll->n->nname is the variable per case
-				escassign(e, ll.N.Nname, n.Left.Right)
+				// n.Left.Right is the argument of the .(type),
+				// ll.N.Rlist is the variable per case
+				if ll.N.Rlist != nil {
+					escassign(e, ll.N.Rlist.N, n.Left.Right)
+				}
 			}
 		}
 

src/cmd/compile/internal/gc/go.y

@@ -549,7 +549,7 @@ case:
 				// type switch - declare variable
 				nn = newname(n.Sym);
 				declare(nn, dclcontext);
-				$$.Nname = nn;
+				$$.Rlist = list1(nn);
 	
 				// keep track of the instances for reporting unused
 				nn.Name.Defn = typesw.Right;
@@ -595,7 +595,7 @@ case:
 				// type switch - declare variable
 				nn = newname(n.Sym);
 				declare(nn, dclcontext);
-				$$.Nname = nn;
+				$$.Rlist = list1(nn);
 	
 				// keep track of the instances for reporting unused
 				nn.Name.Defn = typesw.Right;

src/cmd/compile/internal/gc/swt.go

@@ -165,8 +165,8 @@ func typecheckswitch(n *Node) {
 
 		if top == Etype && n.Type != nil {
 			ll = ncase.List
-			nvar := ncase.Nname
-			if nvar != nil {
+			if ncase.Rlist != nil {
+				nvar := ncase.Rlist.N
 				if ll != nil && ll.Next == nil && ll.N.Type != nil && !Istype(ll.N.Type, TNIL) {
 					// single entry type switch
 					nvar.Name.Param.Ntype = typenod(ll.N.Type)
@@ -176,7 +176,7 @@ func typecheckswitch(n *Node) {
 				}
 
 				typecheck(&nvar, Erv|Easgn)
-				ncase.Nname = nvar
+				ncase.Rlist.N = nvar
 			}
 		}
 
@@ -378,9 +378,9 @@ func casebody(sw *Node, typeswvar *Node) {
 		}
 
 		stat = list(stat, Nod(OLABEL, jmp.Left, nil))
-		if typeswvar != nil && needvar && n.Nname != nil {
-			l := list1(Nod(ODCL, n.Nname, nil))
-			l = list(l, Nod(OAS, n.Nname, typeswvar))
+		if typeswvar != nil && needvar && n.Rlist != nil {
+			l := list1(Nod(ODCL, n.Rlist.N, nil))
+			l = list(l, Nod(OAS, n.Rlist.N, typeswvar))
 			typechecklist(l, Etop)
 			stat = concat(stat, l)
 		}
@@ -645,12 +645,13 @@ func (s *typeSwitch) walk(sw *Node) {
 // typeone generates an AST that jumps to the
 // case body if the variable is of type t.
 func (s *typeSwitch) typeone(t *Node) *Node {
-	name := t.Nname
+	var name *Node
 	var init *NodeList
-	if name == nil {
-		typecheck(&nblank, Erv|Easgn)
+	if t.Rlist == nil {
 		name = nblank
+		typecheck(&nblank, Erv|Easgn)
 	} else {
+		name = t.Rlist.N
 		init = list1(Nod(ODCL, name, nil))
 	}
 

src/cmd/compile/internal/gc/y.go

@@ -1618,7 +1618,7 @@ yydefault:
 					// type switch - declare variable
 					nn = newname(n.Sym)
 					declare(nn, dclcontext)
-					yyVAL.node.Nname = nn
+					yyVAL.node.Rlist = list1(nn)
 
 					// keep track of the instances for reporting unused
 					nn.Name.Defn = typesw.Right
@@ -1670,7 +1670,7 @@ yydefault:
 					// type switch - declare variable
 					nn = newname(n.Sym)
 					declare(nn, dclcontext)
-					yyVAL.node.Nname = nn
+					yyVAL.node.Rlist = list1(nn)
 
 					// keep track of the instances for reporting unused
 					nn.Name.Defn = typesw.Right