Merge changes I0668ff5a,Iff2d7063,I6f8b1e2d,I126db49d,Ic6582260

* changes:
  Exclude source->prebuilt deps from visibility enforcement
  Dedup package build components registration
  Support registering hard coded pre arch mutators
  Added java_system_modules_import
  Document java_system_modules

java/java_test.go

@@ -1261,3 +1261,33 @@ func TestJavaSystemModules(t *testing.T) {
 		}
 	}
 }
+
+func TestJavaSystemModulesImport(t *testing.T) {
+	ctx, _ := testJava(t, `
+		java_system_modules_import {
+			name: "system-modules",
+			libs: ["system-module1", "system-module2"],
+		}
+		java_import {
+			name: "system-module1",
+			jars: ["a.jar"],
+		}
+		java_import {
+			name: "system-module2",
+			jars: ["b.jar"],
+		}
+		`)
+
+	// check the existence of the module
+	systemModules := ctx.ModuleForTests("system-modules", "android_common")
+
+	cmd := systemModules.Rule("jarsTosystemModules")
+
+	// make sure the command compiles against the supplied modules.
+	for _, module := range []string{"system-module1.jar", "system-module2.jar"} {
+		if !strings.Contains(cmd.Args["classpath"], module) {
+			t.Errorf("system modules classpath %v does not contain %q", cmd.Args["classpath"],
+				module)
+		}
+	}
+}

java/system_modules.go

@@ -35,6 +35,7 @@ func init() {
 
 func RegisterSystemModulesBuildComponents(ctx android.RegistrationContext) {
 	ctx.RegisterModuleType("java_system_modules", SystemModulesFactory)
+	ctx.RegisterModuleType("java_system_modules_import", systemModulesImportFactory)
 }
 
 var (
@@ -92,6 +93,9 @@ func TransformJarsToSystemModules(ctx android.ModuleContext, jars android.Paths)
 	return outDir, outputs.Paths()
 }
 
+// java_system_modules creates a system module from a set of java libraries that can
+// be referenced from the system_modules property. It must contain at a minimum the
+// java.base module which must include classes from java.lang amongst other java packages.
 func SystemModulesFactory() android.Module {
 	module := &SystemModules{}
 	module.AddProperties(&module.properties)
@@ -157,3 +161,30 @@ func (system *SystemModules) AndroidMk() android.AndroidMkData {
 		},
 	}
 }
+
+// A prebuilt version of java_system_modules. It does not import the
+// generated system module, it generates the system module from imported
+// java libraries in the same way that java_system_modules does. It just
+// acts as a prebuilt, i.e. can have the same base name as another module
+// type and the one to use is selected at runtime.
+func systemModulesImportFactory() android.Module {
+	module := &systemModulesImport{}
+	module.AddProperties(&module.properties)
+	android.InitPrebuiltModule(module, &module.properties.Libs)
+	android.InitAndroidArchModule(module, android.HostAndDeviceSupported, android.MultilibCommon)
+	android.InitDefaultableModule(module)
+	return module
+}
+
+type systemModulesImport struct {
+	SystemModules
+	prebuilt android.Prebuilt
+}
+
+func (system *systemModulesImport) Name() string {
+	return system.prebuilt.Name(system.ModuleBase.Name())
+}
+
+func (system *systemModulesImport) Prebuilt() *android.Prebuilt {
+	return &system.prebuilt
+}