cmd/compile: use IsSlice and IsArray instead of checking Bound

Changes generated by eg and manually checked.

Isfixedarray, Isslice, and many other
Type-related functions in subr.go should
either be deleted or moved to type.go.
Later, though; the game now is cleanup via encapsulation.

Passes toolstash -cmp.

Change-Id: I83dd8816f6263b74367d23c2719a08c362e330f9
Reviewed-on: https://go-review.googlesource.com/21303Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

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

@@ -240,7 +240,7 @@ func dowidth(t *Type) {
 		if t.Type == nil {
 			break
 		}
-		if t.Bound >= 0 {
+		if t.IsArray() {
 			dowidth(t.Type)
 			if t.Type.Width != 0 {
 				cap := (uint64(Thearch.MAXWIDTH) - 1) / uint64(t.Type.Width)

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

@@ -506,7 +506,7 @@ func (p *exporter) typ(t *Type) {
 		if t.isDDDArray() {
 			Fatalf("array bounds should be known at export time: %v", t)
 		}
-		if t.Bound >= 0 {
+		if t.IsArray() {
 			p.tag(arrayTag)
 			p.int64(t.Bound)
 		} else {

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

@@ -586,7 +586,7 @@ func typefmt(t *Type, flag FmtFlag) string {
 		return "*" + t.Type.String()
 
 	case TARRAY:
-		if t.Bound >= 0 {
+		if t.IsArray() {
 			return fmt.Sprintf("[%d]%v", t.Bound, t.Type)
 		}
 		if t.isDDDArray() {

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

@@ -674,7 +674,7 @@ func haspointers(t *Type) bool {
 		ret = false
 
 	case TARRAY:
-		if t.Bound < 0 { // slice
+		if t.IsSlice() {
 			ret = true
 			break
 		}
@@ -835,7 +835,7 @@ func dcommontype(s *Sym, ot int, t *Type) int {
 	ot = duint8(s, ot, t.Align) // fieldAlign
 
 	i = kinds[t.Etype]
-	if t.Etype == TARRAY && t.Bound < 0 {
+	if t.IsSlice() {
 		i = obj.KindSlice
 	}
 	if !haspointers(t) {
@@ -1114,7 +1114,7 @@ ok:
 		ot = dextratype(s, ot, t, 0)
 
 	case TARRAY:
-		if t.Bound >= 0 {
+		if t.IsArray() {
 			// ../../../../runtime/type.go:/arrayType
 			s1 := dtypesym(t.Type)
 			t2 := typSlice(t.Type)

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

@@ -540,7 +540,7 @@ func getdyn(n *Node, top int) initGenType {
 		return initDynamic
 
 	case OARRAYLIT:
-		if top == 0 && n.Type.Bound < 0 {
+		if top == 0 && n.Type.IsSlice() {
 			return initDynamic
 		}
 
@@ -568,7 +568,7 @@ func structlit(ctxt int, pass int, n *Node, var_ *Node, init *Nodes) {
 
 		switch value.Op {
 		case OARRAYLIT:
-			if value.Type.Bound < 0 {
+			if value.Type.IsSlice() {
 				if pass == 1 && ctxt != 0 {
 					a := NodSym(ODOT, var_, index.Sym)
 					slicelit(ctxt, value, a, init)
@@ -630,7 +630,7 @@ func arraylit(ctxt int, pass int, n *Node, var_ *Node, init *Nodes) {
 
 		switch value.Op {
 		case OARRAYLIT:
-			if value.Type.Bound < 0 {
+			if value.Type.IsSlice() {
 				if pass == 1 && ctxt != 0 {
 					a := Nod(OINDEX, var_, index)
 					slicelit(ctxt, value, a, init)
@@ -804,7 +804,7 @@ func slicelit(ctxt int, n *Node, var_ *Node, init *Nodes) {
 
 		switch value.Op {
 		case OARRAYLIT:
-			if value.Type.Bound < 0 {
+			if value.Type.IsSlice() {
 				break
 			}
 			arraylit(ctxt, 2, value, a, init)
@@ -1076,7 +1076,7 @@ func anylit(ctxt int, n *Node, var_ *Node, init *Nodes) {
 		if t.Etype != TARRAY {
 			Fatalf("anylit: not array")
 		}
-		if t.Bound < 0 {
+		if t.IsSlice() {
 			slicelit(ctxt, n, var_, init)
 			break
 		}
@@ -1195,7 +1195,7 @@ func stataddr(nam *Node, n *Node) bool {
 		return true
 
 	case OINDEX:
-		if n.Left.Type.Bound < 0 {
+		if n.Left.Type.IsSlice() {
 			break
 		}
 		if !stataddr(nam, n.Left) {
@@ -1384,7 +1384,7 @@ func genAsInitNoCheck(n *Node, reportOnly bool) bool {
 		}
 
 		// nr is the array being converted to a slice
-		if nr.Type == nil || nr.Type.Etype != TARRAY || nr.Type.Bound < 0 {
+		if nr.Type == nil || nr.Type.Etype != TARRAY || nr.Type.IsSlice() {
 			return false
 		}
 

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

@@ -583,11 +583,11 @@ func Istype(t *Type, et EType) bool {
 }
 
 func Isfixedarray(t *Type) bool {
-	return t != nil && t.Etype == TARRAY && t.Bound >= 0
+	return t != nil && t.IsArray()
 }
 
 func Isslice(t *Type) bool {
-	return t != nil && t.Etype == TARRAY && t.Bound < 0
+	return t != nil && t.IsSlice()
 }
 
 func isblank(n *Node) bool {

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

@@ -789,6 +789,7 @@ func (t *Type) IsChan() bool {
 }
 
 func (t *Type) IsSlice() bool {
+	// TODO(josharian): Change this to t.Bound == -1.
 	return t.Etype == TARRAY && t.Bound < 0
 }
 

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

@@ -375,7 +375,7 @@ OpSwitch:
 				Yyerror("array bound is too large")
 				n.Type = nil
 				return n
-			} else if t.Bound < 0 {
+			} else if t.IsSlice() {
 				Yyerror("array bound must be non-negative")
 				n.Type = nil
 				return n
@@ -1412,7 +1412,7 @@ OpSwitch:
 			}
 
 		case TARRAY:
-			if t.Bound < 0 { // slice
+			if t.IsSlice() {
 				break
 			}
 			if callrecv(l) { // has call or receive
@@ -2974,7 +2974,7 @@ func typecheckcomplit(n *Node) *Node {
 			i++
 			if int64(i) > length {
 				length = int64(i)
-				if t.Bound >= 0 && length > t.Bound {
+				if t.IsArray() && length > t.Bound {
 					setlineno(l)
 					Yyerror("array index %d out of bounds [0:%d]", length-1, t.Bound)
 					t.Bound = -1 // no more errors
@@ -2991,7 +2991,7 @@ func typecheckcomplit(n *Node) *Node {
 		if t.isDDDArray() {
 			t.Bound = length
 		}
-		if t.Bound < 0 {
+		if t.IsSlice() {
 			n.Right = Nodintconst(length)
 		}
 		n.Op = OARRAYLIT