cmd/compile: delete Func.Outer

This was just storage for a linked list.

Change-Id: I850e8db1e1f5e72410f5c904be9409179b56a94a
Reviewed-on: https://go-review.googlesource.com/23484
Reviewed-by: David Chase <drchase@google.com>

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

@@ -505,10 +505,8 @@ func ifacedcl(n *Node) {
 	n.Func = new(Func)
 	n.Func.FCurfn = Curfn
 	dclcontext = PPARAM
-	markdcl()
-	Funcdepth++
-	n.Func.Outer = Curfn
-	Curfn = n
+	
+	funcstart(n)
 	funcargs(n.Right)
 
 	// funcbody is normally called after the parser has
@@ -535,11 +533,7 @@ func funchdr(n *Node) {
 	}
 
 	dclcontext = PAUTO
-	markdcl()
-	Funcdepth++
-
-	n.Func.Outer = Curfn
-	Curfn = n
+	funcstart(n)
 
 	if n.Func.Nname != nil {
 		funcargs(n.Func.Nname.Name.Param.Ntype)
@@ -672,6 +666,19 @@ func funcargs2(t *Type) {
 	}
 }
 
+var funcstack []*Node // stack of previous values of Curfn
+var Funcdepth int32 // len(funcstack) during parsing, but then forced to be the same later during compilation
+
+
+// start the function.
+// called before funcargs; undone at end of funcbody.
+func funcstart(n *Node) {
+	markdcl()
+	funcstack = append(funcstack, Curfn)
+	Funcdepth++
+	Curfn = n
+}
+
 // finish the body.
 // called in auto-declaration context.
 // returns in extern-declaration context.
@@ -681,9 +688,8 @@ func funcbody(n *Node) {
 		Fatalf("funcbody: unexpected dclcontext %d", dclcontext)
 	}
 	popdcl()
+	funcstack, Curfn = funcstack[:len(funcstack)-1], funcstack[len(funcstack)-1]
 	Funcdepth--
-	Curfn = n.Func.Outer
-	n.Func.Outer = nil
 	if Funcdepth == 0 {
 		dclcontext = PEXTERN
 	}

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

@@ -259,8 +259,6 @@ var Widthreg int
 
 var nblank *Node
 
-var Funcdepth int32
-
 var typecheckok bool
 
 var compiling_runtime bool

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

@@ -23,7 +23,7 @@ func TestSizeof(t *testing.T) {
 		_64bit uintptr     // size on 64bit platforms
 	}{
 		{Flow{}, 52, 88},
-		{Func{}, 96, 168},
+		{Func{}, 92, 160},
 		{Name{}, 52, 80},
 		{Node{}, 92, 144},
 		{Sym{}, 60, 112},

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

@@ -199,9 +199,8 @@ type Func struct {
 	Dcl        []*Node // autodcl for this func/closure
 	Inldcl     Nodes   // copy of dcl for use in inlining
 	Closgen    int
-	Outerfunc  *Node
+	Outerfunc  *Node // outer function (for closure)
 	FieldTrack map[*Sym]struct{}
-	Outer      *Node // outer func for closure
 	Ntype      *Node // signature
 	Top        int   // top context (Ecall, Eproc, etc)
 	Closure    *Node // OCLOSURE <-> ODCLFUNC