VNDK listing contains device modules only

Fix a bug where host-only modules were incorrectly listed as VNDK.
Also refactor VndkMutator() / apexVndkDepsMutator() module skipping
logic.

Bug: 158543482
Test: Add unit test to cc/cc_test.go
Change-Id: I50b09f526cbc081149d8241c2a091e3ee48ef4d7
Merged-In: I50b09f526cbc081149d8241c2a091e3ee48ef4d7
(cherry picked from commit bba545e039)

android/module.go

@@ -819,6 +819,10 @@ func (m *ModuleBase) Host() bool {
 	return m.Os().Class == Host || m.Os().Class == HostCross
 }
 
+func (m *ModuleBase) Device() bool {
+	return m.Os().Class == Device
+}
+
 func (m *ModuleBase) Arch() Arch {
 	return m.Target().Arch
 }

cc/cc_test.go

@@ -430,6 +430,40 @@ func TestVndk(t *testing.T) {
 	checkVndkLibrariesOutput(t, ctx, "vndkcorevariant.libraries.txt", nil)
 }
 
+func TestVndkWithHostSupported(t *testing.T) {
+	ctx := testCc(t, `
+		cc_library {
+			name: "libvndk_host_supported",
+			vendor_available: true,
+			vndk: {
+				enabled: true,
+			},
+			host_supported: true,
+		}
+
+		cc_library {
+			name: "libvndk_host_supported_but_disabled_on_device",
+			vendor_available: true,
+			vndk: {
+				enabled: true,
+			},
+			host_supported: true,
+			enabled: false,
+			target: {
+				host: {
+					enabled: true,
+				}
+			}
+		}
+
+		vndk_libraries_txt {
+			name: "vndkcore.libraries.txt",
+		}
+	`)
+
+	checkVndkLibrariesOutput(t, ctx, "vndkcore.libraries.txt", []string{"libvndk_host_supported.so"})
+}
+
 func TestVndkLibrariesTxtAndroidMk(t *testing.T) {
 	bp := `
 		vndk_libraries_txt {

cc/vndk.go

@@ -334,16 +334,24 @@ func processVndkLibrary(mctx android.BottomUpMutatorContext, m *Module) {
 	}
 }
 
-func IsForVndkApex(mctx android.BottomUpMutatorContext, m *Module) bool {
+// Sanity check for modules that mustn't be VNDK
+func shouldSkipVndkMutator(m *Module) bool {
 	if !m.Enabled() {
-		return false
+		return true
 	}
-
-	if !mctx.Device() {
-		return false
+	if !m.Device() {
+		// Skip non-device modules
+		return true
 	}
-
 	if m.Target().NativeBridge == android.NativeBridgeEnabled {
+		// Skip native_bridge modules
+		return true
+	}
+	return false
+}
+
+func IsForVndkApex(mctx android.BottomUpMutatorContext, m *Module) bool {
+	if shouldSkipVndkMutator(m) {
 		return false
 	}
 
@@ -377,11 +385,8 @@ func VndkMutator(mctx android.BottomUpMutatorContext) {
 	if !ok {
 		return
 	}
-	if !m.Enabled() {
-		return
-	}
-	if m.Target().NativeBridge == android.NativeBridgeEnabled {
-		// Skip native_bridge modules
+
+	if shouldSkipVndkMutator(m) {
 		return
 	}