Implement code-generation step for bp2build.

Implement bp2build codegen as a discrete step that runs after an
alternatively registered pipeline of mutators, instead of a
presingleton.

bp2build codegen requires a Context that supports VisitAllModules and
PathContext, so this CL also makes a BpToBuildWrapperContext that
conforms to PathContext by adding two method implementations.

Test: GENERATE_BAZEL_FILES=true m nothing && bazel query //... --config=bp2build | wc -l # 31433
Test: m queryview && bazel query //... --config=queryview # 63638

Change-Id: I0dd359746584b228046d2d0ff00895f28f9bdfc3

android/register.go

@@ -37,9 +37,6 @@ type singleton struct {
 var singletons []singleton
 var preSingletons []singleton
 
-var bazelConverterSingletons []singleton
-var bazelConverterPreSingletons []singleton
-
 type mutator struct {
 	name            string
 	bottomUpMutator blueprint.BottomUpMutator
@@ -94,14 +91,6 @@ func RegisterPreSingletonType(name string, factory SingletonFactory) {
 	preSingletons = append(preSingletons, singleton{name, factory})
 }
 
-func RegisterBazelConverterSingletonType(name string, factory SingletonFactory) {
-	bazelConverterSingletons = append(bazelConverterSingletons, singleton{name, factory})
-}
-
-func RegisterBazelConverterPreSingletonType(name string, factory SingletonFactory) {
-	bazelConverterPreSingletons = append(bazelConverterPreSingletons, singleton{name, factory})
-}
-
 type Context struct {
 	*blueprint.Context
 	config Config
@@ -117,21 +106,20 @@ func NewContext(config Config) *Context {
 // singletons, module types and mutators to register for converting Blueprint
 // files to semantically equivalent BUILD files.
 func (ctx *Context) RegisterForBazelConversion() {
-	for _, t := range bazelConverterPreSingletons {
-		ctx.RegisterPreSingletonType(t.name, SingletonFactoryAdaptor(ctx, t.factory))
-	}
-
 	for _, t := range moduleTypes {
 		ctx.RegisterModuleType(t.name, ModuleFactoryAdaptor(t.factory))
 	}
 
-	for _, t := range bazelConverterSingletons {
+	// Required for SingletonModule types, even though we are not using them.
+	for _, t := range singletons {
 		ctx.RegisterSingletonType(t.name, SingletonFactoryAdaptor(ctx, t.factory))
 	}
 
 	registerMutatorsForBazelConversion(ctx.Context)
 }
 
+// Register the pipeline of singletons, module types, and mutators for
+// generating build.ninja and other files for Kati, from Android.bp files.
 func (ctx *Context) Register() {
 	for _, t := range preSingletons {
 		ctx.RegisterPreSingletonType(t.name, SingletonFactoryAdaptor(ctx, t.factory))

bp2build/bp2build.go

@@ -16,52 +16,34 @@ package bp2build
 
 import (
 	"android/soong/android"
+	"fmt"
 	"os"
 )
 
-// The Bazel bp2build singleton is responsible for writing .bzl files that are equivalent to
+// The Bazel bp2build code generator is responsible for writing .bzl files that are equivalent to
 // Android.bp files that are capable of being built with Bazel.
-func init() {
+func Codegen(ctx CodegenContext) {
-	android.RegisterBazelConverterPreSingletonType("androidbp_to_build", AndroidBpToBuildSingleton)
+	outputDir := android.PathForOutput(ctx, "bp2build")
-}
+	android.RemoveAllOutputDir(outputDir)
-
-func AndroidBpToBuildSingleton() android.Singleton {
-	return &androidBpToBuildSingleton{
-		name: "bp2build",
-	}
-}
-
-type androidBpToBuildSingleton struct {
-	name      string
-	outputDir android.OutputPath
-}
-
-func (s *androidBpToBuildSingleton) GenerateBuildActions(ctx android.SingletonContext) {
-	s.outputDir = android.PathForOutput(ctx, s.name)
-	android.RemoveAllOutputDir(s.outputDir)
-
-	if !ctx.Config().IsEnvTrue("CONVERT_TO_BAZEL") {
-		return
-	}
 
 	ruleShims := CreateRuleShims(android.ModuleTypeFactories())
 
-	buildToTargets := GenerateSoongModuleTargets(ctx)
+	buildToTargets := GenerateSoongModuleTargets(ctx.Context())
 
 	filesToWrite := CreateBazelFiles(ruleShims, buildToTargets)
 	for _, f := range filesToWrite {
-		if err := s.writeFile(ctx, f); err != nil {
+		if err := writeFile(outputDir, ctx, f); err != nil {
-			ctx.Errorf("Failed to write %q (dir %q) due to %q", f.Basename, f.Dir, err)
+			fmt.Errorf("Failed to write %q (dir %q) due to %q", f.Basename, f.Dir, err)
 		}
 	}
 }
 
-func (s *androidBpToBuildSingleton) getOutputPath(ctx android.PathContext, dir string) android.OutputPath {
+func writeFile(outputDir android.OutputPath, ctx android.PathContext, f BazelFile) error {
-	return s.outputDir.Join(ctx, dir)
+	return writeReadOnlyFile(ctx, getOutputPath(outputDir, ctx, f.Dir), f.Basename, f.Contents)
 }
 
-func (s *androidBpToBuildSingleton) writeFile(ctx android.PathContext, f BazelFile) error {
+func getOutputPath(outputDir android.OutputPath, ctx android.PathContext, dir string) android.OutputPath {
-	return writeReadOnlyFile(ctx, s.getOutputPath(ctx, f.Dir), f.Basename, f.Contents)
+	return outputDir.Join(ctx, dir)
 }
 
 // The auto-conversion directory should be read-only, sufficient for bazel query. The files

bp2build/build_conversion.go

@@ -39,8 +39,26 @@ type bpToBuildContext interface {
 	ModuleSubDir(module blueprint.Module) string
 	ModuleType(module blueprint.Module) string
 
-	VisitAllModulesBlueprint(visit func(blueprint.Module))
+	VisitAllModules(visit func(blueprint.Module))
-	VisitDirectDeps(module android.Module, visit func(android.Module))
+	VisitDirectDeps(module blueprint.Module, visit func(blueprint.Module))
+}
+
+type CodegenContext struct {
+	config  android.Config
+	context android.Context
+}
+
+func (ctx CodegenContext) AddNinjaFileDeps(...string) {}
+func (ctx CodegenContext) Config() android.Config     { return ctx.config }
+func (ctx CodegenContext) Context() android.Context   { return ctx.context }
+
+// NewCodegenContext creates a wrapper context that conforms to PathContext for
+// writing BUILD files in the output directory.
+func NewCodegenContext(config android.Config, context android.Context) CodegenContext {
+	return CodegenContext{
+		context: context,
+		config:  config,
+	}
 }
 
 // props is an unsorted map. This function ensures that
@@ -57,7 +75,7 @@ func propsToAttributes(props map[string]string) string {
 
 func GenerateSoongModuleTargets(ctx bpToBuildContext) map[string][]BazelTarget {
 	buildFileToTargets := make(map[string][]BazelTarget)
-	ctx.VisitAllModulesBlueprint(func(m blueprint.Module) {
+	ctx.VisitAllModules(func(m blueprint.Module) {
 		dir := ctx.ModuleDir(m)
 		t := generateSoongModuleTarget(ctx, m)
 		buildFileToTargets[ctx.ModuleDir(m)] = append(buildFileToTargets[dir], t)
@@ -75,7 +93,7 @@ func generateSoongModuleTarget(ctx bpToBuildContext, m blueprint.Module) BazelTa
 	// out the implications of that.
 	depLabels := map[string]bool{}
 	if aModule, ok := m.(android.Module); ok {
-		ctx.VisitDirectDeps(aModule, func(depModule android.Module) {
+		ctx.VisitDirectDeps(aModule, func(depModule blueprint.Module) {
 			depLabels[qualifiedTargetLabel(ctx, depModule)] = true
 		})
 	}

bp2build/build_conversion_test.go

@@ -200,11 +200,7 @@ func TestGenerateSoongModuleTargets(t *testing.T) {
 		_, errs = ctx.PrepareBuildActions(config)
 		android.FailIfErrored(t, errs)
 
-		bp2BuildCtx := bp2buildBlueprintWrapContext{
+		bazelTargets := GenerateSoongModuleTargets(ctx.Context.Context)[dir]
-			bpCtx: ctx.Context.Context,
-		}
-
-		bazelTargets := GenerateSoongModuleTargets(&bp2BuildCtx)[dir]
 		if g, w := len(bazelTargets), 1; g != w {
 			t.Fatalf("Expected %d bazel target, got %d", w, g)
 		}

bp2build/testing.go

@@ -2,8 +2,6 @@ package bp2build
 
 import (
 	"android/soong/android"
-
-	"github.com/google/blueprint"
 )
 
 type nestedProps struct {
@@ -102,35 +100,3 @@ func customDefaultsModuleFactory() android.Module {
 	android.InitDefaultsModule(m)
 	return m
 }
-
-type bp2buildBlueprintWrapContext struct {
-	bpCtx *blueprint.Context
-}
-
-func (ctx *bp2buildBlueprintWrapContext) ModuleName(module blueprint.Module) string {
-	return ctx.bpCtx.ModuleName(module)
-}
-
-func (ctx *bp2buildBlueprintWrapContext) ModuleDir(module blueprint.Module) string {
-	return ctx.bpCtx.ModuleDir(module)
-}
-
-func (ctx *bp2buildBlueprintWrapContext) ModuleSubDir(module blueprint.Module) string {
-	return ctx.bpCtx.ModuleSubDir(module)
-}
-
-func (ctx *bp2buildBlueprintWrapContext) ModuleType(module blueprint.Module) string {
-	return ctx.bpCtx.ModuleType(module)
-}
-
-func (ctx *bp2buildBlueprintWrapContext) VisitAllModulesBlueprint(visit func(blueprint.Module)) {
-	ctx.bpCtx.VisitAllModules(visit)
-}
-
-func (ctx *bp2buildBlueprintWrapContext) VisitDirectDeps(module android.Module, visit func(android.Module)) {
-	ctx.bpCtx.VisitDirectDeps(module, func(m blueprint.Module) {
-		if aModule, ok := m.(android.Module); ok {
-			visit(aModule)
-		}
-	})
-}

cmd/soong_build/main.go

@@ -23,6 +23,7 @@ import (
 	"github.com/google/blueprint/bootstrap"
 
 	"android/soong/android"
+	"android/soong/bp2build"
 )
 
 var (
@@ -54,18 +55,12 @@ func newNameResolver(config android.Config) *android.NameResolver {
 // bazelConversionRequested checks that the user is intending to convert
 // Blueprint to Bazel BUILD files.
 func bazelConversionRequested(configuration android.Config) bool {
-	return configuration.IsEnvTrue("CONVERT_TO_BAZEL")
+	return configuration.IsEnvTrue("GENERATE_BAZEL_FILES")
 }
 
-func newContext(srcDir string, configuration android.Config) *android.Context {
+func newContext(configuration android.Config) *android.Context {
 	ctx := android.NewContext(configuration)
-	if bazelConversionRequested(configuration) {
+	ctx.Register()
-		// Register an alternate set of singletons and mutators for bazel
-		// conversion for Bazel conversion.
-		ctx.RegisterForBazelConversion()
-	} else {
-		ctx.Register()
-	}
 	if !shouldPrepareBuildActions(configuration) {
 		configuration.SetStopBefore(bootstrap.StopBeforePrepareBuildActions)
 	}
@@ -100,13 +95,22 @@ func main() {
 		// enabled even if it completed successfully.
 		extraNinjaDeps = append(extraNinjaDeps, filepath.Join(configuration.BuildDir(), "always_rerun_for_delve"))
 	}
+
+	if bazelConversionRequested(configuration) {
+		// Run the alternate pipeline of bp2build mutators and singleton to convert Blueprint to BUILD files
+		// before everything else.
+		runBp2Build(configuration, extraNinjaDeps)
+		// Short-circuit and return.
+		return
+	}
+
 	if configuration.BazelContext.BazelEnabled() {
 		// Bazel-enabled mode. Soong runs in two passes.
 		// First pass: Analyze the build tree, but only store all bazel commands
 		// needed to correctly evaluate the tree in the second pass.
 		// TODO(cparsons): Don't output any ninja file, as the second pass will overwrite
 		// the incorrect results from the first pass, and file I/O is expensive.
-		firstCtx := newContext(srcDir, configuration)
+		firstCtx := newContext(configuration)
 		configuration.SetStopBefore(bootstrap.StopBeforeWriteNinja)
 		bootstrap.Main(firstCtx.Context, configuration, extraNinjaDeps...)
 		// Invoke bazel commands and save results for second pass.
@@ -120,10 +124,10 @@ func main() {
 			fmt.Fprintf(os.Stderr, "%s", err)
 			os.Exit(1)
 		}
-		ctx = newContext(srcDir, secondPassConfig)
+		ctx = newContext(secondPassConfig)
 		bootstrap.Main(ctx.Context, secondPassConfig, extraNinjaDeps...)
 	} else {
-		ctx = newContext(srcDir, configuration)
+		ctx = newContext(configuration)
 		bootstrap.Main(ctx.Context, configuration, extraNinjaDeps...)
 	}
 
@@ -154,6 +158,22 @@ func main() {
 	}
 }
 
+// Run Soong in the bp2build mode. This creates a standalone context that registers
+// an alternate pipeline of mutators and singletons specifically for generating
+// Bazel BUILD files instead of Ninja files.
+func runBp2Build(configuration android.Config, extraNinjaDeps []string) {
+	// Register an alternate set of singletons and mutators for bazel
+	// conversion for Bazel conversion.
+	bp2buildCtx := android.NewContext(configuration)
+	bp2buildCtx.RegisterForBazelConversion()
+	configuration.SetStopBefore(bootstrap.StopBeforePrepareBuildActions)
+	bp2buildCtx.SetNameInterface(newNameResolver(configuration))
+	bootstrap.Main(bp2buildCtx.Context, configuration, extraNinjaDeps...)
+
+	codegenContext := bp2build.NewCodegenContext(configuration, *bp2buildCtx)
+	bp2build.Codegen(codegenContext)
+}
+
 // shouldPrepareBuildActions reads configuration and flags if build actions
 // should be generated.
 func shouldPrepareBuildActions(configuration android.Config) bool {

cmd/soong_build/queryview.go

@@ -20,48 +20,11 @@ import (
 	"io/ioutil"
 	"os"
 	"path/filepath"
-
-	"github.com/google/blueprint"
 )
 
-type queryviewContext struct {
-	bpCtx *blueprint.Context
-}
-
-func (ctx *queryviewContext) ModuleName(module blueprint.Module) string {
-	return ctx.bpCtx.ModuleName(module)
-}
-
-func (ctx *queryviewContext) ModuleDir(module blueprint.Module) string {
-	return ctx.bpCtx.ModuleDir(module)
-}
-
-func (ctx *queryviewContext) ModuleSubDir(module blueprint.Module) string {
-	return ctx.bpCtx.ModuleSubDir(module)
-}
-
-func (ctx *queryviewContext) ModuleType(module blueprint.Module) string {
-	return ctx.bpCtx.ModuleType(module)
-}
-
-func (ctx *queryviewContext) VisitAllModulesBlueprint(visit func(blueprint.Module)) {
-	ctx.bpCtx.VisitAllModules(visit)
-}
-
-func (ctx *queryviewContext) VisitDirectDeps(module android.Module, visit func(android.Module)) {
-	ctx.bpCtx.VisitDirectDeps(module, func(m blueprint.Module) {
-		if aModule, ok := m.(android.Module); ok {
-			visit(aModule)
-		}
-	})
-}
-
 func createBazelQueryView(ctx *android.Context, bazelQueryViewDir string) error {
-	qvCtx := queryviewContext{
-		bpCtx: ctx.Context,
-	}
 	ruleShims := bp2build.CreateRuleShims(android.ModuleTypeFactories())
-	buildToTargets := bp2build.GenerateSoongModuleTargets(&qvCtx)
+	buildToTargets := bp2build.GenerateSoongModuleTargets(*ctx)
 
 	filesToWrite := bp2build.CreateBazelFiles(ruleShims, buildToTargets)
 	for _, f := range filesToWrite {