hostdex:true modules are available for platform

Java libraries with hostdex: true are available for the platform even if
it doesn't have "//apex_available:platform" in the apex_available
property. Note that the java libraries are still prevented from being
installed to the device.

Bug: 128708192
Test: m

Change-Id: I6463ebc59cf7fd861b812999d7a79c387bbb3335

android/apex.go

@@ -138,7 +138,7 @@ func (m *ApexModuleBase) IsInstallableToApex() bool {
 }
 
 const (
-	availableToPlatform = "//apex_available:platform"
+	AvailableToPlatform = "//apex_available:platform"
 	availableToAnyApex  = "//apex_available:anyapex"
 )
 
@@ -149,7 +149,7 @@ func CheckAvailableForApex(what string, apex_available []string) bool {
 		return true
 	}
 	return InList(what, apex_available) ||
-		(what != availableToPlatform && InList(availableToAnyApex, apex_available))
+		(what != AvailableToPlatform && InList(availableToAnyApex, apex_available))
 }
 
 func (m *ApexModuleBase) AvailableFor(what string) bool {
@@ -165,7 +165,7 @@ func (m *ApexModuleBase) DepIsInSameApex(ctx BaseModuleContext, dep Module) bool
 
 func (m *ApexModuleBase) checkApexAvailableProperty(mctx BaseModuleContext) {
 	for _, n := range m.ApexProperties.Apex_available {
-		if n == availableToPlatform || n == availableToAnyApex {
+		if n == AvailableToPlatform || n == availableToAnyApex {
 			continue
 		}
 		if !mctx.OtherModuleExists(n) && !mctx.Config().AllowMissingDependencies() {
@@ -179,7 +179,7 @@ func (m *ApexModuleBase) CreateApexVariations(mctx BottomUpMutatorContext) []Mod
 		m.checkApexAvailableProperty(mctx)
 		sort.Strings(m.apexVariations)
 		variations := []string{}
-		availableForPlatform := mctx.Module().(ApexModule).AvailableFor(availableToPlatform) || mctx.Host()
+		availableForPlatform := mctx.Module().(ApexModule).AvailableFor(AvailableToPlatform) || mctx.Host()
 		if availableForPlatform {
 			variations = append(variations, "") // Original variation for platform
 		}

java/androidmk.go

@@ -24,7 +24,7 @@ import (
 func (library *Library) AndroidMkEntriesHostDex() android.AndroidMkEntries {
 	hostDexNeeded := Bool(library.deviceProperties.Hostdex) && !library.Host()
 	if !library.IsForPlatform() {
-		// If the platform variant is available, don't emit hostdex modules from the APEX variants
+		// Don't emit hostdex modules from the APEX variants
 		hostDexNeeded = false
 	}
 
@@ -62,8 +62,14 @@ func (library *Library) AndroidMkEntries() []android.AndroidMkEntries {
 	var entriesList []android.AndroidMkEntries
 
 	mainEntries := android.AndroidMkEntries{Disabled: true}
+
 	// For a java library built for an APEX, we don't need Make module
-	if library.IsForPlatform() {
+	hideFromMake := !library.IsForPlatform()
+	// If not available for platform, don't emit to make.
+	if !library.ApexModuleBase.AvailableFor(android.AvailableToPlatform) {
+		hideFromMake = true
+	}
+	if !hideFromMake {
 		mainEntries = android.AndroidMkEntries{
 			Class:      "JAVA_LIBRARIES",
 			OutputFile: android.OptionalPathForPath(library.outputFile),

java/java.go

@@ -559,6 +559,16 @@ func (j *Module) targetSdkVersion() string {
 	return j.sdkVersion()
 }
 
+func (j *Module) AvailableFor(what string) bool {
+	if what == android.AvailableToPlatform && Bool(j.deviceProperties.Hostdex) {
+		// Exception: for hostdex: true libraries, the platform variant is created
+		// even if it's not marked as available to platform. In that case, the platform
+		// variant is used only for the hostdex and not installed to the device.
+		return true
+	}
+	return j.ApexModuleBase.AvailableFor(what)
+}
+
 func (j *Module) deps(ctx android.BottomUpMutatorContext) {
 	if ctx.Device() {
 		sdkDep := decodeSdkDep(ctx, sdkContext(j))