Make highmem classification of metalava optional

We have added a lot of metalava invocations since the highmem
differentation was added, most of which do not use a lot of memory.

By collecting data of max rss per process we have narrowed down
the set of highmem modules to a smaller set, and will annotate the
relevant modules as such.

Bug: 170701554
Test: NINJA_HIGHMEM_NUM_JOBS=3 m checkapi (no long tail of metalava)
Change-Id: Ic9c8c91388b02889111ef596fc6fd8bde9b42b9d

java/droiddoc.go

@@ -262,6 +262,10 @@ type DroidstubsProperties struct {
 	// TODO(b/146727827): Remove capability when we do not need to generate stubs and API separately.
 	Generate_stubs *bool
 
+	// if set to true, provides a hint to the build system that this rule uses a lot of memory,
+	// whicih can be used for scheduling purposes
+	High_mem *bool
+
 	// is set to true, Metalava will allow framework SDK to contain API levels annotations.
 	Api_levels_annotations_enabled *bool
 
@@ -1260,8 +1264,6 @@ func (d *Droidstubs) apiLevelsAnnotationsFlags(ctx android.ModuleContext, cmd *a
 
 func metalavaCmd(ctx android.ModuleContext, rule *android.RuleBuilder, javaVersion javaVersion, srcs android.Paths,
 	srcJarList android.Path, bootclasspath, classpath classpath, sourcepaths android.Paths, implicitsRsp android.WritablePath, sandbox bool) *android.RuleBuilderCommand {
-	// Metalava uses lots of memory, restrict the number of metalava jobs that can run in parallel.
-	rule.HighMem()
 	cmd := rule.Command()
 	if ctx.Config().UseRBE() && ctx.Config().IsEnvTrue("RBE_METALAVA") {
 		rule.Remoteable(android.RemoteRuleSupports{RBE: true})
@@ -1343,6 +1345,11 @@ func (d *Droidstubs) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 
 	rule := android.NewRuleBuilder()
 
+	if BoolDefault(d.properties.High_mem, false) {
+		// This metalava run uses lots of memory, restrict the number of metalava jobs that can run in parallel.
+		rule.HighMem()
+	}
+
 	generateStubs := BoolDefault(d.properties.Generate_stubs, true)
 	var stubsDir android.OptionalPath
 	if generateStubs {

java/java_test.go

@@ -1232,31 +1232,24 @@ func TestDroiddocArgsAndFlagsCausesError(t *testing.T) {
 func TestDroidstubs(t *testing.T) {
 	ctx, _ := testJavaWithFS(t, `
 		droiddoc_exported_dir {
-		    name: "droiddoc-templates-sdk",
+			name: "droiddoc-templates-sdk",
-		    path: ".",
+			path: ".",
 		}
 
 		droidstubs {
-		    name: "bar-stubs",
+			name: "bar-stubs",
-		    srcs: [
+			srcs: ["bar-doc/a.java"],
-		        "bar-doc/a.java",
+			api_levels_annotations_dirs: ["droiddoc-templates-sdk"],
-				],
+			api_levels_annotations_enabled: true,
-				api_levels_annotations_dirs: [
-					"droiddoc-templates-sdk",
-				],
-				api_levels_annotations_enabled: true,
 		}
 
 		droidstubs {
-		    name: "bar-stubs-other",
+			name: "bar-stubs-other",
-		    srcs: [
+			srcs: ["bar-doc/a.java"],
-		        "bar-doc/a.java",
+			high_mem: true,
-				],
+			api_levels_annotations_dirs: ["droiddoc-templates-sdk"],
-				api_levels_annotations_dirs: [
+			api_levels_annotations_enabled: true,
-					"droiddoc-templates-sdk",
+			api_levels_jar_filename: "android.other.jar",
-				],
-				api_levels_annotations_enabled: true,
-				api_levels_jar_filename: "android.other.jar",
 		}
 		`,
 		map[string][]byte{
@@ -1265,23 +1258,31 @@ func TestDroidstubs(t *testing.T) {
 	testcases := []struct {
 		moduleName          string
 		expectedJarFilename string
+		high_mem            bool
 	}{
 		{
 			moduleName:          "bar-stubs",
 			expectedJarFilename: "android.jar",
+			high_mem:            false,
 		},
 		{
 			moduleName:          "bar-stubs-other",
 			expectedJarFilename: "android.other.jar",
+			high_mem:            true,
 		},
 	}
 	for _, c := range testcases {
 		m := ctx.ModuleForTests(c.moduleName, "android_common")
 		metalava := m.Rule("metalava")
+		rp := metalava.RuleParams
 		expected := "--android-jar-pattern ./%/public/" + c.expectedJarFilename
-		if actual := metalava.RuleParams.Command; !strings.Contains(actual, expected) {
+		if actual := rp.Command; !strings.Contains(actual, expected) {
 			t.Errorf("For %q, expected metalava argument %q, but was not found %q", c.moduleName, expected, actual)
 		}
+
+		if actual := rp.Pool != nil && strings.Contains(rp.Pool.String(), "highmem"); actual != c.high_mem {
+			t.Errorf("Expected %q high_mem to be %v, was %v", c.moduleName, c.high_mem, actual)
+		}
 	}
 }