cmd/compile: make ifaceData accept a position

This lets us provide a better position in its use in swt.go.

Change-Id: I7c0da6bd0adea81acfc9a591e6a01b241a5e0942
Reviewed-on: https://go-review.googlesource.com/c/go/+/228219
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>

3 files changed, 13 insertions, 7 deletions

diff --git a/src/cmd/compile/internal/gc/subr.go b/src/cmd/compile/internal/gc/subr.go
index 7805079a63..ff0fffb9bd 100644
--- a/src/cmd/compile/internal/gc/subr.go
+++ b/src/cmd/compile/internal/gc/subr.go
@@ -376,7 +376,13 @@ func newnamel(pos src.XPos, s *types.Sym) *Node {
 // nodSym makes a Node with Op op and with the Left field set to left
 // and the Sym field set to sym. This is for ODOT and friends.
 func nodSym(op Op, left *Node, sym *types.Sym) *Node {
-	n := nod(op, left, nil)
+	return nodlSym(lineno, op, left, sym)
+}
+
+// nodlSym makes a Node with position Pos, with Op op, and with the Left field set to left
+// and the Sym field set to sym. This is for ODOT and friends.
+func nodlSym(pos src.XPos, op Op, left *Node, sym *types.Sym) *Node {
+	n := nodl(pos, op, left, nil)
 	n.Sym = sym
 	return n
 }
@@ -1896,11 +1902,11 @@ func itabType(itab *Node) *Node {
 // ifaceData loads the data field from an interface.
 // The concrete type must be known to have type t.
 // It follows the pointer if !isdirectiface(t).
-func ifaceData(n *Node, t *types.Type) *Node {
+func ifaceData(pos src.XPos, n *Node, t *types.Type) *Node {
 	if t.IsInterface() {
 		Fatalf("ifaceData interface: %v", t)
 	}
-	ptr := nodSym(OIDATA, n, nil)
+	ptr := nodlSym(pos, OIDATA, n, nil)
 	if isdirectiface(t) {
 		ptr.Type = t
 		ptr.SetTypecheck(1)
@@ -1909,7 +1915,7 @@ func ifaceData(n *Node, t *types.Type) *Node {
 	ptr.Type = types.NewPtr(t)
 	ptr.SetBounded(true)
 	ptr.SetTypecheck(1)
-	ind := nod(ODEREF, ptr, nil)
+	ind := nodl(pos, ODEREF, ptr, nil)
 	ind.Type = t
 	ind.SetTypecheck(1)
 	return ind
diff --git a/src/cmd/compile/internal/gc/swt.go b/src/cmd/compile/internal/gc/swt.go
index 6c931f2dab..88c8ea8146 100644
--- a/src/cmd/compile/internal/gc/swt.go
+++ b/src/cmd/compile/internal/gc/swt.go
@@ -584,7 +584,7 @@ func walkTypeSwitch(sw *Node) {
 				if singleType.IsInterface() {
 					Fatalf("singleType interface should have been handled in Add")
 				}
-				val = ifaceData(s.facename, singleType)
+				val = ifaceData(ncase.Pos, s.facename, singleType)
 			}
 			l := []*Node{
 				nodl(ncase.Pos, ODCL, caseVar, nil),
diff --git a/src/cmd/compile/internal/gc/walk.go b/src/cmd/compile/internal/gc/walk.go
index 56062f8c57..bf12455a5d 100644
--- a/src/cmd/compile/internal/gc/walk.go
+++ b/src/cmd/compile/internal/gc/walk.go
@@ -886,7 +886,7 @@ opswitch:
 			init.Append(nif)
 
 			// Build the result.
-			e := nod(OEFACE, tmp, ifaceData(c, types.NewPtr(types.Types[TUINT8])))
+			e := nod(OEFACE, tmp, ifaceData(n.Pos, c, types.NewPtr(types.Types[TUINT8])))
 			e.Type = toType // assign type manually, typecheck doesn't understand OEFACE.
 			e.SetTypecheck(1)
 			n = e
@@ -3165,7 +3165,7 @@ func walkcompare(n *Node, init *Nodes) *Node {
 			eqtype = nod(andor, nonnil, match)
 		}
 		// Check for data equal.
-		eqdata := nod(eq, ifaceData(l, r.Type), r)
+		eqdata := nod(eq, ifaceData(n.Pos, l, r.Type), r)
 		// Put it all together.
 		expr := nod(andor, eqtype, eqdata)
 		n = finishcompare(n, expr, init)