prog: remove Dir from Type

Having Dir is Type is handy, but forces us to duplicate lots of types.
E.g. if a struct is referenced as both in and out, then we need to
have 2 copies and 2 copies of structs/types it includes.
If also prevents us from having the struct type as struct identity
(because we can have up to 3 of them).

Revert to the old way we used to do it: propagate Dir as we walk
syscall arguments. This moves lots of dir passing from pkg/compiler
to prog package.
Now Arg contains the dir, so once we build the tree, we can use dirs
as before.

Reduces size of sys/linux/gen/amd64.go from 6058336 to 5661150 (-6.6%).

Update #1580

1 files changed, 11 insertions, 6 deletions

diff --git a/prog/prog_test.go b/prog/prog_test.go
index a42e4437f..9b8f442e3 100644
--- a/prog/prog_test.go
+++ b/prog/prog_test.go
@@ -21,8 +21,8 @@ func TestGeneration(t *testing.T) {
 func TestDefault(t *testing.T) {
 	target, _, _ := initTest(t)
 	for _, meta := range target.Syscalls {
-		ForeachType(meta, func(typ Type) {
-			arg := typ.DefaultArg()
+		foreachType(meta, func(typ Type, ctx typeCtx) {
+			arg := typ.DefaultArg(ctx.Dir)
 			if !isDefault(arg) {
 				t.Errorf("default arg is not default: %s\ntype: %#v\narg: %#v",
 					typ, typ, arg)
@@ -203,8 +203,8 @@ func TestSpecialStructs(t *testing.T) {
 			t.Run(special, func(t *testing.T) {
 				var typ Type
 				for i := 0; i < len(target.Syscalls) && typ == nil; i++ {
-					ForeachType(target.Syscalls[i], func(t Type) {
-						if t.Dir() == DirOut {
+					foreachType(target.Syscalls[i], func(t Type, ctx typeCtx) {
+						if ctx.Dir == DirOut {
 							return
 						}
 						if s, ok := t.(*StructType); ok && s.Name() == special {
@@ -220,8 +220,13 @@ func TestSpecialStructs(t *testing.T) {
 				}
 				g := &Gen{newRand(target, rs), newState(target, nil, nil)}
 				for i := 0; i < iters/len(target.SpecialTypes); i++ {
-					arg, _ := gen(g, typ, nil)
-					gen(g, typ, arg)
+					var arg Arg
+					for i := 0; i < 2; i++ {
+						arg, _ = gen(g, typ, DirInOut, arg)
+						if arg.Dir() != DirInOut {
+							t.Fatalf("got wrong arg dir %v", arg.Dir())
+						}
+					}
 				}
 			})
 		}