cmd/internal/gc: make class uint8 throughout

This prevents conversion noise.

No functional changes. Passes toolstash -cmp.

Change-Id: I238adf28680f875217827931a689ce7f19a9b371
Reviewed-on: https://go-review.googlesource.com/8164Reviewed-by: David Chase <drchase@google.com>

src/cmd/internal/gc/dcl.go

@@ -165,7 +165,7 @@ var vargen int
 
 var declare_typegen int
 
-func declare(n *Node, ctxt int) {
+func declare(n *Node, ctxt uint8) {
 	if ctxt == PDISCARD {
 		return
 	}
@@ -232,7 +232,7 @@ func declare(n *Node, ctxt int) {
 	autoexport(n, ctxt)
 }
 
-func addvar(n *Node, t *Type, ctxt int) {
+func addvar(n *Node, t *Type, ctxt uint8) {
 	if n == nil || n.Sym == nil || (n.Op != ONAME && n.Op != ONONAME) || t == nil {
 		Fatal("addvar: n=%v t=%v nil", Nconv(n, 0), Tconv(t, 0))
 	}

src/cmd/internal/gc/export.go

@@ -57,7 +57,7 @@ func exportedsym(sym *Sym) bool {
 	return sym.Pkg == localpkg && exportname(sym.Name)
 }
 
-func autoexport(n *Node, ctxt int) {
+func autoexport(n *Node, ctxt uint8) {
 	if n == nil || n.Sym == nil {
 		return
 	}

src/cmd/internal/gc/go.go

@@ -333,7 +333,7 @@ const (
 
 // declaration context
 const (
-	Pxxx      = iota
+	Pxxx      = uint8(iota)
 	PEXTERN   // global variable
 	PAUTO     // local variables
 	PPARAM    // input arguments
@@ -343,7 +343,7 @@ const (
 
 	PDISCARD // discard during parse of duplicate import
 
-	PHEAP = 1 << 7 // an extra bit to identify an escaped variable
+	PHEAP = uint8(1 << 7) // an extra bit to identify an escaped variable
 )
 
 const (
@@ -594,7 +594,7 @@ var importlist *NodeList // imported functions and methods with inlinable bodies
 
 var funcsyms *NodeList
 
-var dclcontext int // PEXTERN/PAUTO
+var dclcontext uint8 // PEXTERN/PAUTO
 
 var incannedimport int
 

src/cmd/internal/gc/plive.go

@@ -828,10 +828,10 @@ func checkparam(fn *Node, p *obj.Prog, n *Node) {
 		return
 	}
 	var a *Node
-	var class int
+	var class uint8
 	for l := fn.Func.Dcl; l != nil; l = l.Next {
 		a = l.N
-		class = int(a.Class) &^ PHEAP
+		class = a.Class &^ PHEAP
 		if a.Op == ONAME && (class == PPARAM || class == PPARAMOUT) && a == n {
 			return
 		}

src/cmd/internal/gc/racewalk.go

@@ -492,7 +492,7 @@ func callinstr(np **Node, init **NodeList, wr int, skip int) bool {
 	if isartificial(b) {
 		return false
 	}
-	class := int(b.Class)
+	class := b.Class
 
 	// BUG: we _may_ want to instrument PAUTO sometimes
 	// e.g. if we've got a local variable/method receiver

src/cmd/internal/gc/walk.go

@@ -287,9 +287,9 @@ func walkstmt(np **Node) {
 			// so that reorder3 can fix up conflicts
 			var rl *NodeList
 
-			var cl int
+			var cl uint8
 			for ll := Curfn.Func.Dcl; ll != nil; ll = ll.Next {
-				cl = int(ll.N.Class) &^ PHEAP
+				cl = ll.N.Class &^ PHEAP
 				if cl == PAUTO {
 					break
 				}