refactor to use reg.Set

pass/reg.go

@@ -11,8 +11,8 @@ func Liveness(fn *avo.Function) error {
 
 	// Initialize to empty sets.
 	for _, i := range is {
-		i.LiveIn = map[reg.ID]bool{}
-		i.LiveOut = map[reg.ID]bool{}
+		i.LiveIn = reg.NewEmptySet()
+		i.LiveOut = reg.NewEmptySet()
 	}
 
 	// Iterative dataflow analysis.
@@ -22,18 +22,9 @@ func Liveness(fn *avo.Function) error {
 		for _, i := range is {
 			// in[n] = use[n] UNION (out[n] - def[n])
 			nin := len(i.LiveIn)
-			for _, r := range i.InputRegisters() {
-				i.LiveIn[r.ID()] = true
-			}
-			def := map[reg.ID]bool{}
-			for _, r := range i.OutputRegisters() {
-				def[r.ID()] = true
-			}
-			for id := range i.LiveOut {
-				if !def[id] {
-					i.LiveIn[id] = true
-				}
-			}
+			i.LiveIn.Update(reg.NewSetFromSlice(i.InputRegisters()))
+			def := reg.NewSetFromSlice(i.OutputRegisters())
+			i.LiveIn.Update(i.LiveOut.Difference(def))
 			if len(i.LiveIn) != nin {
 				changes = true
 			}
@@ -44,9 +35,7 @@ func Liveness(fn *avo.Function) error {
 				if s == nil {
 					continue
 				}
-				for id := range s.LiveIn {
-					i.LiveOut[id] = true
-				}
+				i.LiveOut.Update(s.LiveIn)
 			}
 			if len(i.LiveOut) != nout {
 				changes = true
@@ -60,3 +49,7 @@ func Liveness(fn *avo.Function) error {
 
 	return nil
 }
+
+func AllocateRegisters(fn *avo.Function) error {
+	return nil
+}

pass/reg_test.go

@@ -50,14 +50,9 @@ func AssertLiveness(t *testing.T, ctx *build.Context, in, out [][]reg.Register)
 	}
 }
 
-func AssertRegistersMatchSet(t *testing.T, rs []reg.Register, s map[reg.ID]bool) {
-	if len(rs) != len(s) {
-		t.Fatalf("size mismatch")
-	}
-	for _, r := range rs {
-		if _, found := s[r.ID()]; !found {
-			t.Fatalf("missing register ID %v", r.ID())
-		}
+func AssertRegistersMatchSet(t *testing.T, rs []reg.Register, s reg.Set) {
+	if !s.Equals(reg.NewSetFromSlice(rs)) {
+		t.Fatalf("register slice does not match set: %#v and %#v", rs, s)
 	}
 }