[dev.regabi] cmd/compile: cleanup for concrete types - mop-up

An automated rewrite will add concrete type assertions after
a test of n.Op(), when n can be safely type-asserted
(meaning, n is not reassigned a different type, n is not reassigned
and then used outside the scope of the type assertion,
and so on).

This sequence of CLs handles the code that the automated
rewrite does not: adding specific types to function arguments,
adjusting code not to call n.Left() etc when n may have multiple
representations, and so on.

This CL handles all the little files that are left.

Passes buildall w/ toolstash -cmp.

Change-Id: I6588c92dbbdd37342a77b365d70e02134a033d2a
Reviewed-on: https://go-review.googlesource.com/c/go/+/277932
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

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

@@ -119,6 +119,7 @@ func widstruct(errtype *types.Type, t *types.Type, o int64, flag int) int64 {
 		}
 		f.Offset = o
 		if n := ir.AsNode(f.Nname); n != nil {
+			n := n.Name()
 			// addrescapes has similar code to update these offsets.
 			// Usually addrescapes runs after widstruct,
 			// in which case we could drop this,

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

@@ -192,7 +192,7 @@ func capturevars(fn *ir.Func) {
 
 		var outer ir.Node
 		outer = v.Outer
-		outermost := v.Defn
+		outermost := v.Defn.(*ir.Name)
 
 		// out parameters will be assigned to implicitly upon return.
 		if outermost.Class() != ir.PPARAMOUT && !outermost.Name().Addrtaken() && !outermost.Name().Assigned() && v.Type().Width <= 128 {
@@ -414,25 +414,26 @@ func walkclosure(clo ir.Node, init *ir.Nodes) ir.Node {
 	return walkexpr(cfn, init)
 }
 
-func typecheckpartialcall(dot ir.Node, sym *types.Sym) *ir.CallPartExpr {
+func typecheckpartialcall(n ir.Node, sym *types.Sym) *ir.CallPartExpr {
-	switch dot.Op() {
+	switch n.Op() {
 	case ir.ODOTINTER, ir.ODOTMETH:
 		break
 
 	default:
 		base.Fatalf("invalid typecheckpartialcall")
 	}
+	dot := n.(*ir.SelectorExpr)
 
 	// Create top-level function.
 	fn := makepartialcall(dot, dot.Type(), sym)
 	fn.SetWrapper(true)
 
-	return ir.NewCallPartExpr(dot.Pos(), dot.Left(), dot.(*ir.SelectorExpr).Selection, fn)
+	return ir.NewCallPartExpr(dot.Pos(), dot.Left(), dot.Selection, fn)
 }
 
 // makepartialcall returns a DCLFUNC node representing the wrapper function (*-fm) needed
 // for partial calls.
-func makepartialcall(dot ir.Node, t0 *types.Type, meth *types.Sym) *ir.Func {
+func makepartialcall(dot *ir.SelectorExpr, t0 *types.Type, meth *types.Sym) *ir.Func {
 	rcvrtype := dot.Left().Type()
 	sym := methodSymSuffix(rcvrtype, meth, "-fm")
 
@@ -508,7 +509,7 @@ func makepartialcall(dot ir.Node, t0 *types.Type, meth *types.Sym) *ir.Func {
 // partialCallType returns the struct type used to hold all the information
 // needed in the closure for n (n must be a OCALLPART node).
 // The address of a variable of the returned type can be cast to a func.
-func partialCallType(n ir.Node) *types.Type {
+func partialCallType(n *ir.CallPartExpr) *types.Type {
 	t := tostruct([]*ir.Field{
 		namedfield("F", types.Types[types.TUINTPTR]),
 		namedfield("R", n.Left().Type()),

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

@@ -165,10 +165,10 @@ func variter(vl []ir.Node, t ir.Ntype, el []ir.Node) []ir.Node {
 			if Curfn != nil {
 				init = append(init, ir.Nod(ir.ODCL, v, nil))
 			}
-			e = ir.Nod(ir.OAS, v, e)
+			as := ir.Nod(ir.OAS, v, e)
-			init = append(init, e)
+			init = append(init, as)
-			if e.Right() != nil {
+			if e != nil {
-				v.Defn = e
+				v.Defn = as
 			}
 		}
 	}
@@ -799,7 +799,7 @@ func makefuncsym(s *types.Sym) {
 }
 
 // setNodeNameFunc marks a node as a function.
-func setNodeNameFunc(n ir.Node) {
+func setNodeNameFunc(n *ir.Name) {
 	if n.Op() != ir.ONAME || n.Class() != ir.Pxxx {
 		base.Fatalf("expected ONAME/Pxxx node, got %v", n)
 	}
@@ -861,12 +861,16 @@ func newNowritebarrierrecChecker() *nowritebarrierrecChecker {
 	return c
 }
 
-func (c *nowritebarrierrecChecker) findExtraCalls(n ir.Node) {
+func (c *nowritebarrierrecChecker) findExtraCalls(nn ir.Node) {
-	if n.Op() != ir.OCALLFUNC {
+	if nn.Op() != ir.OCALLFUNC {
 		return
 	}
-	fn := n.Left()
+	n := nn.(*ir.CallExpr)
-	if fn == nil || fn.Op() != ir.ONAME || fn.Class() != ir.PFUNC || fn.Name().Defn == nil {
+	if n.Left() == nil || n.Left().Op() != ir.ONAME {
+		return
+	}
+	fn := n.Left().(*ir.Name)
+	if fn.Class() != ir.PFUNC || fn.Name().Defn == nil {
 		return
 	}
 	if !isRuntimePkg(fn.Sym().Pkg) || fn.Sym().Name != "systemstack" {

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

@@ -110,7 +110,7 @@ func varEmbed(p *noder, names []ir.Node, typ ir.Ntype, exprs []ir.Node, embeds [
 		}
 	}
 
-	v := names[0]
+	v := names[0].(*ir.Name)
 	if dclcontext != ir.PEXTERN {
 		numLocalEmbed++
 		v = ir.NewNameAt(v.Pos(), lookupN("embed.", numLocalEmbed))

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

@@ -74,7 +74,7 @@ func dumpexport(bout *bio.Writer) {
 	}
 }
 
-func importsym(ipkg *types.Pkg, s *types.Sym, op ir.Op) ir.Node {
+func importsym(ipkg *types.Pkg, s *types.Sym, op ir.Op) *ir.Name {
 	n := ir.AsNode(s.PkgDef())
 	if n == nil {
 		// iimport should have created a stub ONONAME
@@ -92,7 +92,7 @@ func importsym(ipkg *types.Pkg, s *types.Sym, op ir.Op) ir.Node {
 	if n.Op() != ir.ONONAME && n.Op() != op {
 		redeclare(base.Pos, s, fmt.Sprintf("during import %q", ipkg.Path))
 	}
-	return n
+	return n.(*ir.Name)
 }
 
 // importtype returns the named type declared by symbol s.
@@ -102,7 +102,6 @@ func importtype(ipkg *types.Pkg, pos src.XPos, s *types.Sym) *types.Type {
 	n := importsym(ipkg, s, ir.OTYPE)
 	if n.Op() != ir.OTYPE {
 		t := types.NewNamed(n)
-
 		n.SetOp(ir.OTYPE)
 		n.SetPos(pos)
 		n.SetType(t)
@@ -121,7 +120,7 @@ func importtype(ipkg *types.Pkg, pos src.XPos, s *types.Sym) *types.Type {
 func importobj(ipkg *types.Pkg, pos src.XPos, s *types.Sym, op ir.Op, ctxt ir.Class, t *types.Type) ir.Node {
 	n := importsym(ipkg, s, op)
 	if n.Op() != ir.ONONAME {
-		if n.Op() == op && (n.Class() != ctxt || !types.Identical(n.Type(), t)) {
+		if n.Op() == op && (op == ir.ONAME && n.Class() != ctxt || !types.Identical(n.Type(), t)) {
 			redeclare(base.Pos, s, fmt.Sprintf("during import %q", ipkg.Path))
 		}
 		return nil

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

@@ -31,13 +31,21 @@ func sysvar(name string) *obj.LSym {
 // isParamStackCopy reports whether this is the on-stack copy of a
 // function parameter that moved to the heap.
 func isParamStackCopy(n ir.Node) bool {
-	return n.Op() == ir.ONAME && (n.Class() == ir.PPARAM || n.Class() == ir.PPARAMOUT) && n.Name().Heapaddr != nil
+	if n.Op() != ir.ONAME {
+		return false
+	}
+	name := n.(*ir.Name)
+	return (name.Class() == ir.PPARAM || name.Class() == ir.PPARAMOUT) && name.Heapaddr != nil
 }
 
 // isParamHeapCopy reports whether this is the on-heap copy of
 // a function parameter that moved to the heap.
 func isParamHeapCopy(n ir.Node) bool {
-	return n.Op() == ir.ONAME && n.Class() == ir.PAUTOHEAP && n.Name().Stackcopy != nil
+	if n.Op() != ir.ONAME {
+		return false
+	}
+	name := n.(*ir.Name)
+	return name.Class() == ir.PAUTOHEAP && name.Name().Stackcopy != nil
 }
 
 // autotmpname returns the name for an autotmp variable numbered n.

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

@@ -48,10 +48,10 @@ func fninit(n []ir.Node) {
 		if n.Op() == ir.ONONAME {
 			continue
 		}
-		if n.Op() != ir.ONAME || n.Class() != ir.PEXTERN {
+		if n.Op() != ir.ONAME || n.(*ir.Name).Class() != ir.PEXTERN {
 			base.Fatalf("bad inittask: %v", n)
 		}
-		deps = append(deps, n.Sym().Linksym())
+		deps = append(deps, n.(*ir.Name).Sym().Linksym())
 	}
 
 	// Make a function that contains all the initialization statements.
@@ -86,10 +86,10 @@ func fninit(n []ir.Node) {
 	// Record user init functions.
 	for i := 0; i < renameinitgen; i++ {
 		s := lookupN("init.", i)
-		fn := ir.AsNode(s.Def).Name().Defn
+		fn := ir.AsNode(s.Def).Name().Defn.(*ir.Func)
 		// Skip init functions with empty bodies.
 		if fn.Body().Len() == 1 {
-			if stmt := fn.Body().First(); stmt.Op() == ir.OBLOCK && stmt.List().Len() == 0 {
+			if stmt := fn.Body().First(); stmt.Op() == ir.OBLOCK && stmt.(*ir.BlockStmt).List().Len() == 0 {
 				continue
 			}
 		}

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

@@ -323,7 +323,7 @@ func (d *initDeps) foundDep(n *ir.Name) {
 	}
 	d.seen.Add(n)
 	if d.transitive && n.Class() == ir.PFUNC {
-		d.inspectList(n.Defn.Body())
+		d.inspectList(n.Defn.(*ir.Func).Body())
 	}
 }
 

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

@@ -244,7 +244,7 @@ func Main(archInit func(*Arch)) {
 	timings.Start("fe", "typecheck", "top1")
 	for i := 0; i < len(xtop); i++ {
 		n := xtop[i]
-		if op := n.Op(); op != ir.ODCL && op != ir.OAS && op != ir.OAS2 && (op != ir.ODCLTYPE || !n.Left().Name().Alias()) {
+		if op := n.Op(); op != ir.ODCL && op != ir.OAS && op != ir.OAS2 && (op != ir.ODCLTYPE || !n.(*ir.Decl).Left().Name().Alias()) {
 			xtop[i] = typecheck(n, ctxStmt)
 		}
 	}
@@ -256,7 +256,7 @@ func Main(archInit func(*Arch)) {
 	timings.Start("fe", "typecheck", "top2")
 	for i := 0; i < len(xtop); i++ {
 		n := xtop[i]
-		if op := n.Op(); op == ir.ODCL || op == ir.OAS || op == ir.OAS2 || op == ir.ODCLTYPE && n.Left().Name().Alias() {
+		if op := n.Op(); op == ir.ODCL || op == ir.OAS || op == ir.OAS2 || op == ir.ODCLTYPE && n.(*ir.Decl).Left().Name().Alias() {
 			xtop[i] = typecheck(n, ctxStmt)
 		}
 	}

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

@@ -986,7 +986,7 @@ func typenamesym(t *types.Type) *types.Sym {
 	return s
 }
 
-func typename(t *types.Type) ir.Node {
+func typename(t *types.Type) *ir.AddrExpr {
 	s := typenamesym(t)
 	if s.Def == nil {
 		n := ir.NewNameAt(src.NoXPos, s)
@@ -1002,7 +1002,7 @@ func typename(t *types.Type) ir.Node {
 	return n
 }
 
-func itabname(t, itype *types.Type) ir.Node {
+func itabname(t, itype *types.Type) *ir.AddrExpr {
 	if t == nil || (t.IsPtr() && t.Elem() == nil) || t.IsUntyped() || !itype.IsInterface() || itype.IsEmptyInterface() {
 		base.Fatalf("itabname(%v, %v)", t, itype)
 	}

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

@@ -101,9 +101,11 @@ func (v *bottomUpVisitor) visit(n *ir.Func) uint32 {
 			}
 		case ir.OCALLPART:
 			fn := ir.AsNode(callpartMethod(n).Nname)
-			if fn != nil && fn.Op() == ir.ONAME && fn.Class() == ir.PFUNC && fn.Name().Defn != nil {
+			if fn != nil && fn.Op() == ir.ONAME {
-				if m := v.visit(fn.Name().Defn.(*ir.Func)); m < min {
+				if fn := fn.(*ir.Name); fn.Class() == ir.PFUNC && fn.Name().Defn != nil {
-					min = m
+					if m := v.visit(fn.Name().Defn.(*ir.Func)); m < min {
+						min = m
+					}
 				}
 			}
 		case ir.OCLOSURE:

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

@@ -1234,7 +1234,7 @@ func genwrapper(rcvr *types.Type, method *types.Field, newnam *types.Sym) {
 		left := dot.Left() // skip final .M
 		// TODO(mdempsky): Remove dependency on dotlist.
 		if !dotlist[0].field.Type.IsPtr() {
-			left = ir.Nod(ir.OADDR, left, nil)
+			left = nodAddr(left)
 		}
 		as := ir.Nod(ir.OAS, nthis, convnop(left, rcvr))
 		fn.PtrBody().Append(as)

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

@@ -2791,7 +2791,7 @@ func pushtype(nn ir.Node, t *types.Type) ir.Node {
 		// For *T, return &T{...}.
 		n.SetRight(ir.TypeNode(t.Elem()))
 
-		addr := ir.NodAt(n.Pos(), ir.OADDR, n, nil)
+		addr := nodAddrAt(n.Pos(), n)
 		addr.SetImplicit(true)
 		return addr
 	}

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

@@ -152,23 +152,27 @@ func initUniverse() {
 
 	for _, s := range &builtinFuncs {
 		s2 := types.BuiltinPkg.Lookup(s.name)
-		s2.Def = NewName(s2)
+		def := NewName(s2)
-		ir.AsNode(s2.Def).SetSubOp(s.op)
+		def.SetSubOp(s.op)
+		s2.Def = def
 	}
 
 	for _, s := range &unsafeFuncs {
 		s2 := unsafepkg.Lookup(s.name)
-		s2.Def = NewName(s2)
+		def := NewName(s2)
-		ir.AsNode(s2.Def).SetSubOp(s.op)
+		def.SetSubOp(s.op)
+		s2.Def = def
 	}
 
 	s = types.BuiltinPkg.Lookup("true")
-	s.Def = nodbool(true)
+	b := nodbool(true)
-	ir.AsNode(s.Def).SetSym(lookup("true"))
+	b.(*ir.Name).SetSym(lookup("true"))
+	s.Def = b
 
 	s = types.BuiltinPkg.Lookup("false")
-	s.Def = nodbool(false)
+	b = nodbool(false)
-	ir.AsNode(s.Def).SetSym(lookup("false"))
+	b.(*ir.Name).SetSym(lookup("false"))
+	s.Def = b
 
 	s = lookup("_")
 	types.BlankSym = s
@@ -187,8 +191,9 @@ func initUniverse() {
 
 	types.Types[types.TNIL] = types.New(types.TNIL)
 	s = types.BuiltinPkg.Lookup("nil")
-	s.Def = nodnil()
+	nnil := nodnil()
-	ir.AsNode(s.Def).SetSym(s)
+	nnil.(*ir.NilExpr).SetSym(s)
+	s.Def = nnil
 
 	s = types.BuiltinPkg.Lookup("iota")
 	s.Def = ir.NewIota(base.Pos, s)

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

@@ -31,18 +31,20 @@ func evalunsafe(n ir.Node) int64 {
 			base.Errorf("invalid expression %v", n)
 			return 0
 		}
+		sel := n.Left().(*ir.SelectorExpr)
 
 		// Remember base of selector to find it back after dot insertion.
 		// Since r->left may be mutated by typechecking, check it explicitly
 		// first to track it correctly.
-		n.Left().SetLeft(typecheck(n.Left().Left(), ctxExpr))
+		sel.SetLeft(typecheck(sel.Left(), ctxExpr))
-		sbase := n.Left().Left()
+		sbase := sel.Left()
 
-		n.SetLeft(typecheck(n.Left(), ctxExpr))
+		tsel := typecheck(sel, ctxExpr)
-		if n.Left().Type() == nil {
+		n.SetLeft(tsel)
+		if tsel.Type() == nil {
 			return 0
 		}
-		switch n.Left().Op() {
+		switch tsel.Op() {
 		case ir.ODOT, ir.ODOTPTR:
 			break
 		case ir.OCALLPART:
@@ -55,7 +57,8 @@ func evalunsafe(n ir.Node) int64 {
 
 		// Sum offsets for dots until we reach sbase.
 		var v int64
-		for r := n.Left(); r != sbase; r = r.Left() {
+		var next ir.Node
+		for r := tsel; r != sbase; r = next {
 			switch r.Op() {
 			case ir.ODOTPTR:
 				// For Offsetof(s.f), s may itself be a pointer,
@@ -68,8 +71,9 @@ func evalunsafe(n ir.Node) int64 {
 				fallthrough
 			case ir.ODOT:
 				v += r.Offset()
+				next = r.Left()
 			default:
-				ir.Dump("unsafenmagic", n.Left())
+				ir.Dump("unsafenmagic", tsel)
 				base.Fatalf("impossible %v node after dot insertion", r.Op())
 			}
 		}