diff --git a/android/mutator.go b/android/mutator.go
index eba0e2f..e9ccd7f 100644
--- a/android/mutator.go
+++ b/android/mutator.go
@@ -78,11 +78,11 @@
 	registerLoadHookMutator,
 	RegisterNamespaceMutator,
 	// Rename package module types.
-	registerPackageRenamer,
+	RegisterPackageRenamer,
 	RegisterPrebuiltsPreArchMutators,
-	registerVisibilityRuleChecker,
+	RegisterVisibilityRuleChecker,
 	RegisterDefaultsPreArchMutators,
-	registerVisibilityRuleGatherer,
+	RegisterVisibilityRuleGatherer,
 }
 
 func registerArchMutator(ctx RegisterMutatorsContext) {
@@ -99,7 +99,7 @@
 var postDeps = []RegisterMutatorFunc{
 	registerPathDepsMutator,
 	RegisterPrebuiltsPostDepsMutators,
-	registerVisibilityRuleEnforcer,
+	RegisterVisibilityRuleEnforcer,
 	registerNeverallowMutator,
 	RegisterOverridePostDepsMutators,
 }
diff --git a/android/package.go b/android/package.go
index 880d6a9..ed604c6 100644
--- a/android/package.go
+++ b/android/package.go
@@ -98,7 +98,7 @@
 }
 
 // Registers the function that renames the packages.
-func registerPackageRenamer(ctx RegisterMutatorsContext) {
+func RegisterPackageRenamer(ctx RegisterMutatorsContext) {
 	ctx.BottomUp("packageRenamer", packageRenamer).Parallel()
 	ctx.BottomUp("packageErrorReporter", packageErrorReporter).Parallel()
 }
diff --git a/android/package_test.go b/android/package_test.go
index ae286d6..8071c51 100644
--- a/android/package_test.go
+++ b/android/package_test.go
@@ -88,7 +88,7 @@
 
 	ctx := NewTestArchContext()
 	ctx.RegisterModuleType("package", PackageFactory)
-	ctx.PreArchMutators(registerPackageRenamer)
+	ctx.PreArchMutators(RegisterPackageRenamer)
 	ctx.Register()
 
 	ctx.MockFileSystem(fs)
diff --git a/android/visibility.go b/android/visibility.go
index a7e718b..c28ec93 100644
--- a/android/visibility.go
+++ b/android/visibility.go
@@ -117,12 +117,15 @@
 }
 
 func (c compositeRule) String() string {
+	return "[" + strings.Join(c.Strings(), ", ") + "]"
+}
+
+func (c compositeRule) Strings() []string {
 	s := make([]string, 0, len(c))
 	for _, r := range c {
 		s = append(s, r.String())
 	}
-
-	return "[" + strings.Join(s, ", ") + "]"
+	return s
 }
 
 // A packageRule is a visibility rule that matches modules in a specific package (i.e. directory).
@@ -189,7 +192,7 @@
 
 // The rule checker needs to be registered before defaults expansion to correctly check that
 // //visibility:xxx isn't combined with other packages in the same list in any one module.
-func registerVisibilityRuleChecker(ctx RegisterMutatorsContext) {
+func RegisterVisibilityRuleChecker(ctx RegisterMutatorsContext) {
 	ctx.BottomUp("visibilityRuleChecker", visibilityRuleChecker).Parallel()
 }
 
@@ -199,12 +202,12 @@
 // having to process multiple variants for each module. This goes after defaults expansion to gather
 // the complete visibility lists from flat lists and after the package info is gathered to ensure
 // that default_visibility is available.
-func registerVisibilityRuleGatherer(ctx RegisterMutatorsContext) {
+func RegisterVisibilityRuleGatherer(ctx RegisterMutatorsContext) {
 	ctx.BottomUp("visibilityRuleGatherer", visibilityRuleGatherer).Parallel()
 }
 
 // This must be registered after the deps have been resolved.
-func registerVisibilityRuleEnforcer(ctx RegisterMutatorsContext) {
+func RegisterVisibilityRuleEnforcer(ctx RegisterMutatorsContext) {
 	ctx.TopDown("visibilityRuleEnforcer", visibilityRuleEnforcer).Parallel()
 }
 
@@ -384,8 +387,6 @@
 
 	qualified := createQualifiedModuleName(ctx)
 
-	moduleToVisibilityRule := moduleToVisibilityRuleMap(ctx)
-
 	// Visit all the dependencies making sure that this module has access to them all.
 	ctx.VisitDirectDeps(func(dep Module) {
 		depName := ctx.OtherModuleName(dep)
@@ -397,19 +398,25 @@
 			return
 		}
 
-		value, ok := moduleToVisibilityRule.Load(depQualified)
-		var rule compositeRule
-		if ok {
-			rule = value.(compositeRule)
-		} else {
-			rule = packageDefaultVisibility(ctx, depQualified)
-		}
+		rule := effectiveVisibilityRules(ctx, depQualified)
 		if rule != nil && !rule.matches(qualified) {
 			ctx.ModuleErrorf("depends on %s which is not visible to this module", depQualified)
 		}
 	})
 }
 
+func effectiveVisibilityRules(ctx BaseModuleContext, qualified qualifiedModuleName) compositeRule {
+	moduleToVisibilityRule := moduleToVisibilityRuleMap(ctx)
+	value, ok := moduleToVisibilityRule.Load(qualified)
+	var rule compositeRule
+	if ok {
+		rule = value.(compositeRule)
+	} else {
+		rule = packageDefaultVisibility(ctx, qualified)
+	}
+	return rule
+}
+
 func createQualifiedModuleName(ctx BaseModuleContext) qualifiedModuleName {
 	moduleName := ctx.ModuleName()
 	dir := ctx.ModuleDir()
@@ -433,3 +440,19 @@
 		packageQualifiedId = packageQualifiedId.getContainingPackageId()
 	}
 }
+
+// Get the effective visibility rules, i.e. the actual rules that affect the visibility of the
+// property irrespective of where they are defined.
+//
+// Includes visibility rules specified by package default_visibility and/or on defaults.
+// Short hand forms, e.g. //:__subpackages__ are replaced with their full form, e.g.
+// //package/containing/rule:__subpackages__.
+func EffectiveVisibilityRules(ctx BaseModuleContext, module Module) []string {
+	moduleName := ctx.OtherModuleName(module)
+	dir := ctx.OtherModuleDir(module)
+	qualified := qualifiedModuleName{dir, moduleName}
+
+	rule := effectiveVisibilityRules(ctx, qualified)
+
+	return rule.Strings()
+}
diff --git a/android/visibility_test.go b/android/visibility_test.go
index fd9e98c..1984a21 100644
--- a/android/visibility_test.go
+++ b/android/visibility_test.go
@@ -874,11 +874,11 @@
 	ctx.RegisterModuleType("package", PackageFactory)
 	ctx.RegisterModuleType("mock_library", newMockLibraryModule)
 	ctx.RegisterModuleType("mock_defaults", defaultsFactory)
-	ctx.PreArchMutators(registerPackageRenamer)
-	ctx.PreArchMutators(registerVisibilityRuleChecker)
+	ctx.PreArchMutators(RegisterPackageRenamer)
+	ctx.PreArchMutators(RegisterVisibilityRuleChecker)
 	ctx.PreArchMutators(RegisterDefaultsPreArchMutators)
-	ctx.PreArchMutators(registerVisibilityRuleGatherer)
-	ctx.PostDepsMutators(registerVisibilityRuleEnforcer)
+	ctx.PreArchMutators(RegisterVisibilityRuleGatherer)
+	ctx.PostDepsMutators(RegisterVisibilityRuleEnforcer)
 	ctx.Register()
 
 	ctx.MockFileSystem(fs)