Add system_modules to droidstubs

This allows droidstubs to use the same system modules to create the
stubs that will be used to compile them. It improves consistency and
avoids droidstubs having to duplicate the libraries that make up the
system modules on its libs property.

Adds systemModules() to the sdkContext which allows consistent error
checking behavior between droidstubs and java_library.

Bug: 142534789
Test: m checkbuild
Change-Id: Ib2006906d9528a900f16851f50b62152ffb51a1b

java/aar.go

@@ -520,6 +520,10 @@ func (a *AARImport) sdkVersion() string {
 	return proptools.StringDefault(a.properties.Sdk_version, defaultSdkVersion(a))
 }
 
+func (a *AARImport) systemModules() string {
+	return ""
+}
+
 func (a *AARImport) minSdkVersion() string {
 	if a.properties.Min_sdk_version != nil {
 		return *a.properties.Min_sdk_version

java/droiddoc.go

@@ -67,9 +67,15 @@ type JavadocProperties struct {
 	// If set to false, don't allow this module(-docs.zip) to be exported. Defaults to true.
 	Installable *bool
 
-	// if not blank, set to the version of the sdk to compile against
+	// if not blank, set to the version of the sdk to compile against.
+	// Defaults to compiling against the current platform.
 	Sdk_version *string `android:"arch_variant"`
 
+	// When targeting 1.9 and above, override the modules to use with --system,
+	// otherwise provides defaults libraries to add to the bootclasspath.
+	// Defaults to "none"
+	System_modules *string
+
 	Aidl struct {
 		// Top level directories to pass to aidl tool
 		Include_dirs []string
@@ -401,6 +407,10 @@ func (j *Javadoc) sdkVersion() string {
 	return proptools.StringDefault(j.properties.Sdk_version, defaultSdkVersion(j))
 }
 
+func (j *Javadoc) systemModules() string {
+	return proptools.String(j.properties.System_modules)
+}
+
 func (j *Javadoc) minSdkVersion() string {
 	return j.sdkVersion()
 }
@@ -427,6 +437,10 @@ func (j *Javadoc) addDeps(ctx android.BottomUpMutatorContext) {
 				}
 				ctx.AddVariationDependencies(nil, bootClasspathTag, sdkDep.modules...)
 			}
+		} else if sdkDep.systemModules != "" {
+			// Add the system modules to both the system modules and bootclasspath.
+			ctx.AddVariationDependencies(nil, systemModulesTag, sdkDep.systemModules)
+			ctx.AddVariationDependencies(nil, bootClasspathTag, sdkDep.systemModules)
 		}
 	}
 
@@ -514,6 +528,10 @@ func (j *Javadoc) collectDeps(ctx android.ModuleContext) deps {
 		case bootClasspathTag:
 			if dep, ok := module.(Dependency); ok {
 				deps.bootClasspath = append(deps.bootClasspath, dep.ImplementationJars()...)
+			} else if sm, ok := module.(*SystemModules); ok {
+				// A system modules dependency has been added to the bootclasspath
+				// so add its libs to the bootclasspath.
+				deps.bootClasspath = append(deps.bootClasspath, sm.headerJars...)
 			} else {
 				panic(fmt.Errorf("unknown dependency %q for %q", otherName, ctx.ModuleName()))
 			}

java/java.go

@@ -270,7 +270,8 @@ type CompilerDeviceProperties struct {
 		Proguard_flags_files []string `android:"path"`
 	}
 
-	// When targeting 1.9, override the modules to use with --system
+	// When targeting 1.9 and above, override the modules to use with --system,
+	// otherwise provides defaults libraries to add to the bootclasspath.
 	System_modules *string
 
 	UncompressDex bool `blueprint:"mutated"`
@@ -457,7 +458,10 @@ type checkVendorModuleContext interface {
 type sdkDep struct {
 	useModule, useFiles, useDefaultLibs, invalidVersion bool
 
-	modules       []string
+	modules []string
+
+	// The default system modules to use. Will be an empty string if no system
+	// modules are to be used.
 	systemModules string
 
 	frameworkResModule string
@@ -496,6 +500,10 @@ func (j *Module) sdkVersion() string {
 	return proptools.StringDefault(j.deviceProperties.Sdk_version, defaultSdkVersion(j))
 }
 
+func (j *Module) systemModules() string {
+	return proptools.String(j.deviceProperties.System_modules)
+}
+
 func (j *Module) minSdkVersion() string {
 	if j.deviceProperties.Min_sdk_version != nil {
 		return *j.deviceProperties.Min_sdk_version
@@ -528,13 +536,10 @@ func (j *Module) deps(ctx android.BottomUpMutatorContext) {
 					ctx.AddVariationDependencies(nil, proguardRaiseTag, config.DefaultLibraries...)
 				}
 			}
-		} else if j.deviceProperties.System_modules == nil {
-			ctx.PropertyErrorf("sdk_version",
-				`system_modules is required to be set when sdk_version is "none", did you mean "core_platform"`)
-		} else if *j.deviceProperties.System_modules != "none" {
+		} else if sdkDep.systemModules != "" {
 			// Add the system modules to both the system modules and bootclasspath.
-			ctx.AddVariationDependencies(nil, systemModulesTag, *j.deviceProperties.System_modules)
-			ctx.AddVariationDependencies(nil, bootClasspathTag, *j.deviceProperties.System_modules)
+			ctx.AddVariationDependencies(nil, systemModulesTag, sdkDep.systemModules)
+			ctx.AddVariationDependencies(nil, bootClasspathTag, sdkDep.systemModules)
 		}
 		if ctx.ModuleName() == "android_stubs_current" ||
 			ctx.ModuleName() == "android_system_stubs_current" ||

java/sdk.go

@@ -39,6 +39,8 @@ var apiFingerprintPathKey = android.NewOnceKey("apiFingerprintPathKey")
 type sdkContext interface {
 	// sdkVersion returns the sdk_version property of the current module, or an empty string if it is not set.
 	sdkVersion() string
+	// systemModules returns the system_modules property of the current module, or an empty string if it is not set.
+	systemModules() string
 	// minSdkVersion returns the min_sdk_version property of the current module, or sdkVersion() if it is not set.
 	minSdkVersion() string
 	// targetSdkVersion returns the target_sdk_version property of the current module, or sdkVersion() if it is not set.
@@ -185,8 +187,18 @@ func decodeSdkDep(ctx android.BaseModuleContext, sdkContext sdkContext) sdkDep {
 			frameworkResModule: "framework-res",
 		}
 	case "none":
+		systemModules := sdkContext.systemModules()
+		if systemModules == "" {
+			ctx.PropertyErrorf("sdk_version",
+				`system_modules is required to be set to a non-empty value when sdk_version is "none", did you mean sdk_version: "core_platform"?`)
+		} else if systemModules == "none" {
+			// Normalize no system modules to an empty string.
+			systemModules = ""
+		}
+
 		return sdkDep{
 			noStandardLibs: true,
+			systemModules:  systemModules,
 		}
 	case "core_platform":
 		return sdkDep{