cmd/compile: use one format for exporting calls of builtin functions

Minor cleanup. Each of these cases appears both during export and
import when running all.bash and thus is tested by all.bash.

Change-Id: Iaa4a5a5b163cefe33e43d08d396e02a02e5c22a5
Reviewed-on: https://go-review.googlesource.com/23060Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

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

@@ -1256,26 +1256,35 @@ func (p *exporter) expr(n *Node) {
 		p.expr(max)
 
 	case OCOPY, OCOMPLEX:
+		// treated like other builtin calls (see e.g., OREAL)
 		p.op(op)
 		p.expr(n.Left)
 		p.expr(n.Right)
+		p.op(OEND)
 
 	case OCONV, OCONVIFACE, OCONVNOP, OARRAYBYTESTR, OARRAYRUNESTR, OSTRARRAYBYTE, OSTRARRAYRUNE, ORUNESTR:
 		p.op(OCONV)
 		p.typ(n.Type)
-		if p.bool(n.Left != nil) {
+		if n.Left != nil {
 			p.expr(n.Left)
+			p.op(OEND)
 		} else {
-			p.exprList(n.List)
+			p.exprList(n.List) // emits terminating OEND
 		}
 
 	case OREAL, OIMAG, OAPPEND, OCAP, OCLOSE, ODELETE, OLEN, OMAKE, ONEW, OPANIC, ORECOVER, OPRINT, OPRINTN:
 		p.op(op)
-		if p.bool(n.Left != nil) {
+		if n.Left != nil {
 			p.expr(n.Left)
+			p.op(OEND)
 		} else {
-			p.exprList(n.List)
+			p.exprList(n.List) // emits terminating OEND
+		}
+		// only append() calls may contain '...' arguments
+		if op == OAPPEND {
 			p.bool(n.Isddd)
+		} else if n.Isddd {
+			Fatalf("exporter: unexpected '...' with %s call", opnames[op])
 		}
 
 	case OCALL, OCALLFUNC, OCALLMETH, OCALLINTER, OGETG:

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

@@ -884,29 +884,18 @@ func (p *importer) node() *Node {
 		n.SetSliceBounds(low, high, max)
 		return n
 
-	case OCOPY, OCOMPLEX:
-		n := builtinCall(op)
-		n.List.Set([]*Node{p.expr(), p.expr()})
-		return n
-
 	// case OCONV, OCONVIFACE, OCONVNOP, OARRAYBYTESTR, OARRAYRUNESTR, OSTRARRAYBYTE, OSTRARRAYRUNE, ORUNESTR:
 	// 	unreachable - mapped to OCONV case below by exporter
 
 	case OCONV:
 		n := Nod(OCALL, typenod(p.typ()), nil)
-		if p.bool() {
-			n.List.Set1(p.expr())
-		} else {
-			n.List.Set(p.exprList())
-		}
+		n.List.Set(p.exprList())
 		return n
 
-	case OREAL, OIMAG, OAPPEND, OCAP, OCLOSE, ODELETE, OLEN, OMAKE, ONEW, OPANIC, ORECOVER, OPRINT, OPRINTN:
+	case OCOPY, OCOMPLEX, OREAL, OIMAG, OAPPEND, OCAP, OCLOSE, ODELETE, OLEN, OMAKE, ONEW, OPANIC, ORECOVER, OPRINT, OPRINTN:
 		n := builtinCall(op)
-		if p.bool() {
-			n.List.Set1(p.expr())
-		} else {
-			n.List.Set(p.exprList())
+		n.List.Set(p.exprList())
+		if op == OAPPEND {
 			n.Isddd = p.bool()
 		}
 		return n