cmd/compile: encapsulate map value type

Passes toolstash -cmp.

Change-Id: I83af544974e1e91e0810e13321afb3e665dcdf12
Reviewed-on: https://go-review.googlesource.com/21248
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

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

@@ -213,8 +213,7 @@ func dowidth(t *Type) {
 
 	case TMAP: // implemented as pointer
 		w = int64(Widthptr)
-
+		checkwidth(t.Val())
-		checkwidth(t.Type)
 		checkwidth(t.Key())
 
 	case TFORW: // should have been filled in

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

@@ -542,8 +542,8 @@ func (p *exporter) typ(t *Type) {
 
 	case TMAP:
 		p.tag(mapTag)
-		p.typ(t.Key()) // key
+		p.typ(t.Key())
-		p.typ(t.Type)  // val
+		p.typ(t.Val())
 
 	case TCHAN:
 		p.tag(chanTag)

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

@@ -609,7 +609,7 @@ func typefmt(t *Type, flag FmtFlag) string {
 		return "chan " + t.Type.String()
 
 	case TMAP:
-		return "map[" + t.Key().String() + "]" + t.Type.String()
+		return "map[" + t.Key().String() + "]" + t.Val().String()
 
 	case TINTER:
 		var buf bytes.Buffer
@@ -674,15 +674,15 @@ func typefmt(t *Type, flag FmtFlag) string {
 			// Format the bucket struct for map[x]y as map.bucket[x]y.
 			// This avoids a recursive print that generates very long names.
 			if t.Map.Bucket == t {
-				return "map.bucket[" + t.Map.Key().String() + "]" + t.Map.Type.String()
+				return "map.bucket[" + t.Map.Key().String() + "]" + t.Map.Val().String()
 			}
 
 			if t.Map.Hmap == t {
-				return "map.hdr[" + t.Map.Key().String() + "]" + t.Map.Type.String()
+				return "map.hdr[" + t.Map.Key().String() + "]" + t.Map.Val().String()
 			}
 
 			if t.Map.Hiter == t {
-				return "map.iter[" + t.Map.Key().String() + "]" + t.Map.Type.String()
+				return "map.iter[" + t.Map.Key().String() + "]" + t.Map.Val().String()
 			}
 
 			Yyerror("unknown internal map type")

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

@@ -55,7 +55,7 @@ func typecheckrange(n *Node) {
 
 	case TMAP:
 		t1 = t.Key()
-		t2 = t.Type
+		t2 = t.Val()
 
 	case TCHAN:
 		if t.Chan&Crecv == 0 {
@@ -231,7 +231,7 @@ func walkrange(n *Node) {
 
 		fn := syslook("mapiterinit")
 
-		fn = substArgTypes(fn, t.Key(), t.Type, th)
+		fn = substArgTypes(fn, t.Key(), t.Val(), th)
 		init = append(init, mkcall1(fn, nil, nil, typename(t), ha, Nod(OADDR, hit, nil)))
 		n.Left = Nod(ONE, NodSym(ODOT, hit, keysym), nodnil())
 

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

@@ -82,7 +82,7 @@ func mapbucket(t *Type) *Type {
 
 	bucket := typ(TSTRUCT)
 	keytype := t.Key()
-	valtype := t.Type
+	valtype := t.Val()
 	dowidth(keytype)
 	dowidth(valtype)
 	if keytype.Width > MAXKEYSIZE {
@@ -125,7 +125,7 @@ func mapbucket(t *Type) *Type {
 	// so if the struct needs 64-bit padding (because a key or value does)
 	// then it would end with an extra 32-bit padding field.
 	// Preempt that by emitting the padding here.
-	if int(t.Type.Align) > Widthptr || int(t.Key().Align) > Widthptr {
+	if int(t.Val().Align) > Widthptr || int(t.Key().Align) > Widthptr {
 		field = append(field, makefield("pad", Types[TUINTPTR]))
 	}
 
@@ -136,7 +136,7 @@ func mapbucket(t *Type) *Type {
 	// the type of the overflow field to uintptr in this case.
 	// See comment on hmap.overflow in ../../../../runtime/hashmap.go.
 	otyp := Ptrto(bucket)
-	if !haspointers(t.Type) && !haspointers(t.Key()) && t.Type.Width <= MAXVALSIZE && t.Key().Width <= MAXKEYSIZE {
+	if !haspointers(t.Val()) && !haspointers(t.Key()) && t.Val().Width <= MAXVALSIZE && t.Key().Width <= MAXKEYSIZE {
 		otyp = Types[TUINTPTR]
 	}
 	ovf := makefield("overflow", otyp)
@@ -211,7 +211,7 @@ func hiter(t *Type) *Type {
 	// must match ../../../../runtime/hashmap.go:hiter.
 	var field [12]*Field
 	field[0] = makefield("key", Ptrto(t.Key()))
-	field[1] = makefield("val", Ptrto(t.Type))
+	field[1] = makefield("val", Ptrto(t.Val()))
 	field[2] = makefield("t", Ptrto(Types[TUINT8]))
 	field[3] = makefield("h", Ptrto(hmap(t)))
 	field[4] = makefield("buckets", Ptrto(mapbucket(t)))
@@ -1226,7 +1226,7 @@ ok:
 	// ../../../../runtime/type.go:/mapType
 	case TMAP:
 		s1 := dtypesym(t.Key())
-		s2 := dtypesym(t.Type)
+		s2 := dtypesym(t.Val())
 		s3 := dtypesym(mapbucket(t))
 		s4 := dtypesym(hmap(t))
 		ot = dcommontype(s, ot, t)
@@ -1242,11 +1242,11 @@ ok:
 			ot = duint8(s, ot, 0) // not indirect
 		}
 
-		if t.Type.Width > MAXVALSIZE {
+		if t.Val().Width > MAXVALSIZE {
 			ot = duint8(s, ot, uint8(Widthptr))
 			ot = duint8(s, ot, 1) // indirect
 		} else {
-			ot = duint8(s, ot, uint8(t.Type.Width))
+			ot = duint8(s, ot, uint8(t.Val().Width))
 			ot = duint8(s, ot, 0) // not indirect
 		}
 

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

@@ -860,7 +860,7 @@ func maplit(ctxt int, n *Node, var_ *Node, init *Nodes) {
 		// build type [count]struct { a Tindex, b Tvalue }
 		t := n.Type
 		tk := t.Key()
-		tv := t.Type
+		tv := t.Val()
 
 		syma := Lookup("a")
 		symb := Lookup("b")
@@ -969,7 +969,7 @@ func maplit(ctxt int, n *Node, var_ *Node, init *Nodes) {
 		// use temporary so that mapassign1 can have addressable key, val.
 		if key == nil {
 			key = temp(var_.Type.Key())
-			val = temp(var_.Type.Type)
+			val = temp(var_.Type.Val())
 		}
 
 		setlineno(r.Left)

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

@@ -773,6 +773,7 @@ func eqtype1(t1, t2 *Type, assumedEqual map[typePair]struct{}) bool {
 		if !eqtype1(t1.Key(), t2.Key(), assumedEqual) {
 			return false
 		}
+		return eqtype1(t1.Val(), t2.Val(), assumedEqual)
 	}
 
 	return eqtype1(t1.Type, t2.Type, assumedEqual)

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

@@ -342,6 +342,12 @@ func (t *Type) Key() *Type {
 	return t.Down
 }
 
+// Val returns the value type of map type t.
+func (t *Type) Val() *Type {
+	t.wantEtype(TMAP)
+	return t.Type
+}
+
 func (t *Type) Methods() *Fields {
 	// TODO(mdempsky): Validate t?
 	return &t.methods
@@ -524,9 +530,10 @@ func (t *Type) cmp(x *Type) ssa.Cmp {
 
 	switch t.Etype {
 	case TMAP:
-		if c := t.Down.cmp(x.Down); c != ssa.CMPeq {
+		if c := t.Key().cmp(x.Key()); c != ssa.CMPeq {
 			return c
 		}
+		return t.Val().cmp(x.Val())
 
 	case TPTR32, TPTR64:
 		// No special cases for these two, they are handled
@@ -614,7 +621,7 @@ func (t *Type) cmp(x *Type) ssa.Cmp {
 		panic(e)
 	}
 
-	// Common element type comparison for TARRAY, TCHAN, TMAP, TPTR32, and TPTR64.
+	// Common element type comparison for TARRAY, TCHAN, TPTR32, and TPTR64.
 	return t.Type.cmp(x.Type)
 }
 

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

@@ -1026,7 +1026,7 @@ OpSwitch:
 			if n.Right.Type != nil {
 				n.Right = assignconv(n.Right, t.Key(), "map index")
 			}
-			n.Type = t.Type
+			n.Type = t.Val()
 			n.Op = OINDEXMAP
 		}
 
@@ -3021,10 +3021,10 @@ func typecheckcomplit(n *Node) *Node {
 			}
 
 			r = l.Right
-			pushtype(r, t.Type)
+			pushtype(r, t.Val())
 			r = typecheck(r, Erv)
-			r = defaultlit(r, t.Type)
+			r = defaultlit(r, t.Val())
-			l.Right = assignconv(r, t.Type, "map value")
+			l.Right = assignconv(r, t.Val(), "map value")
 		}
 
 		n.Op = OMAPLIT

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

@@ -835,7 +835,7 @@ opswitch:
 		r.Right = walkexpr(r.Right, init)
 		t := r.Left.Type
 		p := ""
-		if t.Type.Width <= 128 { // Check ../../runtime/hashmap.go:maxValueSize before changing.
+		if t.Val().Width <= 128 { // Check ../../runtime/hashmap.go:maxValueSize before changing.
 			switch algtype(t.Key()) {
 			case AMEM32:
 				p = "mapaccess2_fast32"
@@ -879,7 +879,7 @@ opswitch:
 
 		// don't generate a = *var if a is _
 		if !isblank(a) {
-			var_ := temp(Ptrto(t.Type))
+			var_ := temp(Ptrto(t.Val()))
 			var_.Typecheck = 1
 			n.List.SetIndex(0, var_)
 			n = walkexpr(n, init)
@@ -1200,7 +1200,7 @@ opswitch:
 
 		t := n.Left.Type
 		p := ""
-		if t.Type.Width <= 128 { // Check ../../runtime/hashmap.go:maxValueSize before changing.
+		if t.Val().Width <= 128 { // Check ../../runtime/hashmap.go:maxValueSize before changing.
 			switch algtype(t.Key()) {
 			case AMEM32:
 				p = "mapaccess1_fast32"
@@ -1223,9 +1223,9 @@ opswitch:
 			p = "mapaccess1"
 		}
 
-		n = mkcall1(mapfn(p, t), Ptrto(t.Type), init, typename(t), n.Left, key)
+		n = mkcall1(mapfn(p, t), Ptrto(t.Val()), init, typename(t), n.Left, key)
 		n = Nod(OIND, n, nil)
-		n.Type = t.Type
+		n.Type = t.Val()
 		n.Typecheck = 1
 
 	case ORECV:
@@ -1393,7 +1393,7 @@ opswitch:
 		}
 
 		fn := syslook("makemap")
-		fn = substArgTypes(fn, hmap(t), mapbucket(t), t.Key(), t.Type)
+		fn = substArgTypes(fn, hmap(t), mapbucket(t), t.Key(), t.Val())
 		n = mkcall1(fn, n.Type, init, typename(n.Type), conv(n.Left, Types[TINT64]), a, r)
 
 	case OMAKESLICE:
@@ -2647,7 +2647,7 @@ func mapfn(name string, t *Type) *Node {
 		Fatalf("mapfn %v", t)
 	}
 	fn := syslook(name)
-	fn = substArgTypes(fn, t.Key(), t.Type, t.Key(), t.Type)
+	fn = substArgTypes(fn, t.Key(), t.Val(), t.Key(), t.Val())
 	return fn
 }
 
@@ -2656,7 +2656,7 @@ func mapfndel(name string, t *Type) *Node {
 		Fatalf("mapfn %v", t)
 	}
 	fn := syslook(name)
-	fn = substArgTypes(fn, t.Key(), t.Type, t.Key())
+	fn = substArgTypes(fn, t.Key(), t.Val(), t.Key())
 	return fn
 }