cmd/compile: simplify staticname

Add docs.
Give it a more natural signature.

Passes toolstash -cmp.

Change-Id: Iab368dd10e8f16e41b725c2980020bbead2cdefb
Reviewed-on: https://go-review.googlesource.com/26756
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

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

@@ -400,7 +400,7 @@ func staticassign(l *Node, r *Node, out *[]*Node) bool {
 		switch r.Left.Op {
 		case OARRAYLIT, OSLICELIT, OMAPLIT, OSTRUCTLIT:
 			// Init pointer.
-			a := staticname(r.Left.Type, inNonInitFunction)
+			a := staticname(r.Left.Type)
 
 			inittemps[r] = a
 			gdata(l, Nod(OADDR, a, nil), int(l.Type.Width))
@@ -425,7 +425,7 @@ func staticassign(l *Node, r *Node, out *[]*Node) bool {
 		// Init slice.
 		bound := r.Right.Int64()
 		ta := typArray(r.Type.Elem(), bound)
-		a := staticname(ta, inNonInitFunction)
+		a := staticname(ta)
 		inittemps[r] = a
 		n := *l
 		n.Xoffset = l.Xoffset + int64(Array_array)
@@ -507,12 +507,13 @@ const (
 // most of the work is to generate
 // data statements for the constant
 // part of the composite literal.
-func staticname(t *Type, ctxt initContext) *Node {
+
+// staticname return a name backed by a static data symbol.
+// Callers should set n.Name.Readonly = true on the
+// returned node for readonly nodes.
+func staticname(t *Type) *Node {
 	n := newname(LookupN("statictmp_", statuniqgen))
 	statuniqgen++
-	if ctxt == inInitFunction {
-		n.Name.Readonly = true
-	}
 	addvar(n, t, PEXTERN)
 	return n
 }
@@ -684,7 +685,7 @@ func slicelit(ctxt initContext, n *Node, var_ *Node, init *Nodes) {
 
 	if ctxt == inNonInitFunction {
 		// put everything into static array
-		vstat := staticname(t, ctxt)
+		vstat := staticname(t)
 
 		fixedlit(ctxt, initKindStatic, n, vstat, init)
 		fixedlit(ctxt, initKindDynamic, n, vstat, init)
@@ -724,7 +725,10 @@ func slicelit(ctxt initContext, n *Node, var_ *Node, init *Nodes) {
 
 	mode := getdyn(n, true)
 	if mode&initConst != 0 {
-		vstat = staticname(t, ctxt)
+		vstat = staticname(t)
+		if ctxt == inInitFunction {
+			vstat.Name.Readonly = true
+		}
 		fixedlit(ctxt, initKindStatic, n, vstat, init)
 	}
 
@@ -819,8 +823,6 @@ func slicelit(ctxt initContext, n *Node, var_ *Node, init *Nodes) {
 }
 
 func maplit(ctxt initContext, n *Node, m *Node, init *Nodes) {
-	ctxt = inInitFunction
-
 	// make the map var
 	nerr := nerrors
 
@@ -852,8 +854,10 @@ func maplit(ctxt initContext, n *Node, m *Node, init *Nodes) {
 		dowidth(tv)
 
 		// make and initialize static arrays
-		vstatk := staticname(tk, ctxt)
-		vstatv := staticname(tv, ctxt)
+		vstatk := staticname(tk)
+		vstatk.Name.Readonly = true
+		vstatv := staticname(tv)
+		vstatv.Name.Readonly = true
 
 		b := int64(0)
 		for _, r := range n.List.Slice() {
@@ -1005,7 +1009,8 @@ func anylit(ctxt initContext, n *Node, var_ *Node, init *Nodes) {
 		if var_.isSimpleName() && n.List.Len() > 4 {
 			if ctxt == inInitFunction {
 				// lay out static data
-				vstat := staticname(t, ctxt)
+				vstat := staticname(t)
+				vstat.Name.Readonly = true
 
 				litctxt := ctxt
 				if n.Op == OARRAYLIT {

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

@@ -1636,7 +1636,8 @@ opswitch:
 		if isStaticCompositeLiteral(n) {
 			// n can be directly represented in the read-only data section.
 			// Make direct reference to the static data. See issue 12841.
-			vstat := staticname(n.Type, inInitFunction)
+			vstat := staticname(n.Type)
+			vstat.Name.Readonly = true
 			fixedlit(inInitFunction, initKindStatic, n, vstat, init)
 			n = vstat
 			n = typecheck(n, Erv)