Add FinalDeps mutator phase, where CreateVariations is disallowed.

This is for use to add dependencies between specific module variants,
without getting the dependencies potentially duplicated as more
variants are created.

Moved genrule tool dependency registration to this phase, to avoid
potential splitting of its dependencies, and for consistency with the
same kind of dependency on dex2oat in https://r.android.com/1205730.

Test: m nothing
Bug: 145934348
Change-Id: I1f9e75354e359cef5f41d14e5016b0a67d7655d7

android/mutator_test.go

@@ -15,9 +15,12 @@
 package android
 
 import (
+	"fmt"
 	"reflect"
+	"strings"
 	"testing"
 
+	"github.com/google/blueprint"
 	"github.com/google/blueprint/proptools"
 )
 
@@ -185,3 +188,110 @@ func TestModuleString(t *testing.T) {
 		t.Errorf("want module String() values:\n%q\ngot:\n%q", want, moduleStrings)
 	}
 }
+
+func TestFinalDepsPhase(t *testing.T) {
+	ctx := NewTestContext()
+
+	finalGot := map[string]int{}
+
+	dep1Tag := struct {
+		blueprint.BaseDependencyTag
+	}{}
+	dep2Tag := struct {
+		blueprint.BaseDependencyTag
+	}{}
+
+	ctx.PostDepsMutators(func(ctx RegisterMutatorsContext) {
+		ctx.BottomUp("far_deps_1", func(ctx BottomUpMutatorContext) {
+			if !strings.HasPrefix(ctx.ModuleName(), "common_dep") {
+				ctx.AddFarVariationDependencies([]blueprint.Variation{}, dep1Tag, "common_dep_1")
+			}
+		})
+		ctx.BottomUp("variant", func(ctx BottomUpMutatorContext) {
+			ctx.CreateLocalVariations("a", "b")
+		})
+	})
+
+	ctx.FinalDepsMutators(func(ctx RegisterMutatorsContext) {
+		ctx.BottomUp("far_deps_2", func(ctx BottomUpMutatorContext) {
+			if !strings.HasPrefix(ctx.ModuleName(), "common_dep") {
+				ctx.AddFarVariationDependencies([]blueprint.Variation{}, dep2Tag, "common_dep_2")
+			}
+		})
+		ctx.BottomUp("final", func(ctx BottomUpMutatorContext) {
+			finalGot[ctx.Module().String()] += 1
+			ctx.VisitDirectDeps(func(mod Module) {
+				finalGot[fmt.Sprintf("%s -> %s", ctx.Module().String(), mod)] += 1
+			})
+		})
+	})
+
+	ctx.RegisterModuleType("test", mutatorTestModuleFactory)
+
+	bp := `
+		test {
+			name: "common_dep_1",
+		}
+		test {
+			name: "common_dep_2",
+		}
+		test {
+			name: "foo",
+		}
+	`
+
+	config := TestConfig(buildDir, nil, bp, nil)
+	ctx.Register(config)
+
+	_, errs := ctx.ParseFileList(".", []string{"Android.bp"})
+	FailIfErrored(t, errs)
+	_, errs = ctx.PrepareBuildActions(config)
+	FailIfErrored(t, errs)
+
+	finalWant := map[string]int{
+		"common_dep_1{variant:a}":                   1,
+		"common_dep_1{variant:b}":                   1,
+		"common_dep_2{variant:a}":                   1,
+		"common_dep_2{variant:b}":                   1,
+		"foo{variant:a}":                            1,
+		"foo{variant:a} -> common_dep_1{variant:a}": 1,
+		"foo{variant:a} -> common_dep_2{variant:a}": 1,
+		"foo{variant:b}":                            1,
+		"foo{variant:b} -> common_dep_1{variant:b}": 1,
+		"foo{variant:b} -> common_dep_2{variant:a}": 1,
+	}
+
+	if !reflect.DeepEqual(finalWant, finalGot) {
+		t.Errorf("want:\n%q\ngot:\n%q", finalWant, finalGot)
+	}
+}
+
+func TestNoCreateVariationsInFinalDeps(t *testing.T) {
+	ctx := NewTestContext()
+
+	checkErr := func() {
+		if err := recover(); err == nil || !strings.Contains(fmt.Sprintf("%s", err), "not allowed in FinalDepsMutators") {
+			panic("Expected FinalDepsMutators consistency check to fail")
+		}
+	}
+
+	ctx.FinalDepsMutators(func(ctx RegisterMutatorsContext) {
+		ctx.BottomUp("vars", func(ctx BottomUpMutatorContext) {
+			defer checkErr()
+			ctx.CreateVariations("a", "b")
+		})
+		ctx.BottomUp("local_vars", func(ctx BottomUpMutatorContext) {
+			defer checkErr()
+			ctx.CreateLocalVariations("a", "b")
+		})
+	})
+
+	ctx.RegisterModuleType("test", mutatorTestModuleFactory)
+	config := TestConfig(buildDir, nil, `test {name: "foo"}`, nil)
+	ctx.Register(config)
+
+	_, errs := ctx.ParseFileList(".", []string{"Android.bp"})
+	FailIfErrored(t, errs)
+	_, errs = ctx.PrepareBuildActions(config)
+	FailIfErrored(t, errs)
+}