cmd/compile/internal/gc: convert fields of Symlink to bool

Convert two fields of struct Symlink in subr.go from uint8 to bool.

This change passes go build -toolexec 'toolstash -cmp' -a std.

Change-Id: I913006f41605b17b0d82fe358ee773f6ecaa681c
Reviewed-on: https://go-review.googlesource.com/14378Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

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

@@ -2163,17 +2163,17 @@ func adddot(n *Node) *Node {
  */
 type Symlink struct {
 	field     *Type
-	good      uint8
-	followptr uint8
 	link      *Symlink
+	good      bool
+	followptr bool
 }
 
 var slist *Symlink
 
-func expand0(t *Type, followptr int) {
+func expand0(t *Type, followptr bool) {
 	u := t
 	if Isptr[u.Etype] {
-		followptr = 1
+		followptr = true
 		u = u.Type
 	}
 
@@ -2187,7 +2187,7 @@ func expand0(t *Type, followptr int) {
 			sl = new(Symlink)
 			sl.field = f
 			sl.link = slist
-			sl.followptr = uint8(followptr)
+			sl.followptr = followptr
 			slist = sl
 		}
 
@@ -2205,13 +2205,13 @@ func expand0(t *Type, followptr int) {
 			sl = new(Symlink)
 			sl.field = f
 			sl.link = slist
-			sl.followptr = uint8(followptr)
+			sl.followptr = followptr
 			slist = sl
 		}
 	}
 }
 
-func expand1(t *Type, d int, followptr int) {
+func expand1(t *Type, d int, followptr bool) {
 	if t.Trecur != 0 {
 		return
 	}
@@ -2226,7 +2226,7 @@ func expand1(t *Type, d int, followptr int) {
 
 	u := t
 	if Isptr[u.Etype] {
-		followptr = 1
+		followptr = true
 		u = u.Type
 	}
 
@@ -2263,7 +2263,7 @@ func expandmeth(t *Type) {
 	// generate all reachable methods
 	slist = nil
 
-	expand1(t, len(dotlist)-1, 0)
+	expand1(t, len(dotlist)-1, false)
 
 	// check each method to be uniquely reachable
 	var c int
@@ -2278,7 +2278,7 @@ func expandmeth(t *Type) {
 			if c == 1 {
 				// addot1 may have dug out arbitrary fields, we only want methods.
 				if f.Type.Etype == TFUNC && f.Type.Thistuple > 0 {
-					sl.good = 1
+					sl.good = true
 					sl.field = f
 				}
 			}
@@ -2293,13 +2293,13 @@ func expandmeth(t *Type) {
 
 	t.Xmethod = t.Method
 	for sl := slist; sl != nil; sl = sl.link {
-		if sl.good != 0 {
+		if sl.good {
 			// add it to the base type method list
 			f = typ(TFIELD)
 
 			*f = *sl.field
 			f.Embedded = 1 // needs a trampoline
-			if sl.followptr != 0 {
+			if sl.followptr {
 				f.Embedded = 2
 			}
 			f.Down = t.Xmethod
@@ -2968,8 +2968,8 @@ func geneq(sym *Sym, t *Type) {
 	safemode = old_safemode
 }
 
-func ifacelookdot(s *Sym, t *Type, followptr *int, ignorecase int) *Type {
-	*followptr = 0
+func ifacelookdot(s *Sym, t *Type, followptr *bool, ignorecase int) *Type {
+	*followptr = false
 
 	if t == nil {
 		return nil
@@ -2988,7 +2988,7 @@ func ifacelookdot(s *Sym, t *Type, followptr *int, ignorecase int) *Type {
 		if c == 1 {
 			for i = 0; i < d; i++ {
 				if Isptr[dotlist[i].field.Type.Etype] {
-					*followptr = 1
+					*followptr = true
 					break
 				}
 			}
@@ -3046,7 +3046,7 @@ func implements(t *Type, iface *Type, m **Type, samename **Type, ptr *int) bool
 	}
 	var tm *Type
 	var imtype *Type
-	var followptr int
+	var followptr bool
 	var rcvr *Type
 	for im := iface.Type; im != nil; im = im.Down {
 		imtype = methodfunc(im.Type, nil)
@@ -3065,7 +3065,7 @@ func implements(t *Type, iface *Type, m **Type, samename **Type, ptr *int) bool
 		// the method does not exist for value types.
 		rcvr = getthisx(tm.Type).Type.Type
 
-		if Isptr[rcvr.Etype] && !Isptr[t0.Etype] && followptr == 0 && !isifacemethod(tm.Type) {
+		if Isptr[rcvr.Etype] && !Isptr[t0.Etype] && !followptr && !isifacemethod(tm.Type) {
 			if false && Debug['r'] != 0 {
 				Yyerror("interface pointer mismatch")
 			}