Separate HostOrDevice out of Arch

Take HostOrDevice out of Arch, and put it into AndroidModuleBase
instead.  Also separate out the host vs. device mutator from
ArchMutator.  This will make it possible for genrules to depend
on a host tool, regardless of which host arches it is compiled
for.

Change-Id: I22bbfd28b65c3eebdfa101a712f90dd615148dc8

common/arch.go

@@ -129,15 +129,14 @@ type archProperties struct {
 
 // An Arch indicates a single CPU architecture.
 type Arch struct {
-	HostOrDevice HostOrDevice
-	ArchType     ArchType
-	ArchVariant  string
-	CpuVariant   string
-	Abi          string
+	ArchType    ArchType
+	ArchVariant string
+	CpuVariant  string
+	Abi         string
 }
 
 func (a Arch) String() string {
-	s := a.HostOrDevice.String() + "_" + a.ArchType.String()
+	s := a.ArchType.String()
 	if a.ArchVariant != "" {
 		s += "_" + a.ArchVariant
 	}
@@ -247,37 +246,60 @@ var hostOrDeviceName = map[HostOrDevice]string{
 
 var (
 	armArch = Arch{
-		HostOrDevice: Device,
-		ArchType:     Arm,
-		ArchVariant:  "armv7-a-neon",
-		CpuVariant:   "cortex-a15",
-		Abi:          "armeabi-v7a",
+		ArchType:    Arm,
+		ArchVariant: "armv7-a-neon",
+		CpuVariant:  "cortex-a15",
+		Abi:         "armeabi-v7a",
 	}
 	arm64Arch = Arch{
-		HostOrDevice: Device,
-		ArchType:     Arm64,
-		ArchVariant:  "armv8-a",
-		CpuVariant:   "denver",
-		Abi:          "arm64-v8a",
+		ArchType:    Arm64,
+		ArchVariant: "armv8-a",
+		CpuVariant:  "denver",
+		Abi:         "arm64-v8a",
 	}
-	hostArch = Arch{
-		HostOrDevice: Host,
-		ArchType:     X86,
+	x86Arch = Arch{
+		ArchType: X86,
 	}
-	host64Arch = Arch{
-		HostOrDevice: Host,
-		ArchType:     X86_64,
+	x8664Arch = Arch{
+		ArchType: X86_64,
 	}
-	commonDevice = Arch{
-		HostOrDevice: Device,
-		ArchType:     Common,
-	}
-	commonHost = Arch{
-		HostOrDevice: Host,
-		ArchType:     Common,
+	commonArch = Arch{
+		ArchType: Common,
 	}
 )
 
+func HostOrDeviceMutator(mctx blueprint.EarlyMutatorContext) {
+	var module AndroidModule
+	var ok bool
+	if module, ok = mctx.Module().(AndroidModule); !ok {
+		return
+	}
+
+	hods := []HostOrDevice{}
+
+	if module.base().HostSupported() {
+		hods = append(hods, Host)
+	}
+
+	if module.base().DeviceSupported() {
+		hods = append(hods, Device)
+	}
+
+	if len(hods) == 0 {
+		return
+	}
+
+	hodNames := []string{}
+	for _, hod := range hods {
+		hodNames = append(hodNames, hod.String())
+	}
+
+	modules := mctx.CreateVariations(hodNames...)
+	for i, m := range modules {
+		m.(AndroidModule).base().SetHostOrDevice(hods[i])
+	}
+}
+
 func ArchMutator(mctx blueprint.EarlyMutatorContext) {
 	var module AndroidModule
 	var ok bool
@@ -290,19 +312,19 @@ func ArchMutator(mctx blueprint.EarlyMutatorContext) {
 
 	arches := []Arch{}
 
-	if module.base().HostSupported() {
+	if module.base().HostSupported() && module.base().HostOrDevice().Host() {
 		switch module.base().commonProperties.Compile_multilib {
 		case "common":
-			arches = append(arches, commonHost)
+			arches = append(arches, commonArch)
 		default:
-			arches = append(arches, host64Arch)
+			arches = append(arches, x8664Arch)
 		}
 	}
 
-	if module.base().DeviceSupported() {
+	if module.base().DeviceSupported() && module.base().HostOrDevice().Device() {
 		switch module.base().commonProperties.Compile_multilib {
 		case "common":
-			arches = append(arches, commonDevice)
+			arches = append(arches, commonArch)
 		case "both":
 			arches = append(arches, arm64Arch, armArch)
 		case "first", "64":
@@ -328,7 +350,7 @@ func ArchMutator(mctx blueprint.EarlyMutatorContext) {
 
 	for i, m := range modules {
 		m.(AndroidModule).base().SetArch(arches[i])
-		m.(AndroidModule).base().setArchProperties(mctx, arches[i])
+		m.(AndroidModule).base().setArchProperties(mctx)
 	}
 }
 
@@ -373,7 +395,10 @@ func InitArchModule(m AndroidModule, defaultMultilib Multilib,
 }
 
 // Rewrite the module's properties structs to contain arch-specific values.
-func (a *AndroidModuleBase) setArchProperties(ctx blueprint.EarlyMutatorContext, arch Arch) {
+func (a *AndroidModuleBase) setArchProperties(ctx blueprint.EarlyMutatorContext) {
+	arch := a.commonProperties.CompileArch
+	hod := a.commonProperties.CompileHostOrDevice
+
 	if arch.ArchType == Common {
 		return
 	}
@@ -406,7 +431,6 @@ func (a *AndroidModuleBase) setArchProperties(ctx blueprint.EarlyMutatorContext,
 		//         key: value,
 		//     },
 		// },
-		hod := arch.HostOrDevice
 		a.extendProperties(ctx, "target", hod.FieldLower(), generalPropsValue,
 			reflect.ValueOf(a.archProperties[i].Target).FieldByName(hod.Field()).Elem().Elem())