Create a AOSP Bazel overlay workspace with Soong
The Bazel overlay is a directory at out/soong/bazel_overlay that
replicates the layout of the AOSP Soong module tree, but as a Bazel
workspace. Each Soong module variant is represented as a BUILD target
created with the `soong_module` rule.
To create this overlay, run `m bazel_overlay`.
A `soong_module` target can depend on other `soong_module` targets.
These dependencies replicate each module's `directDeps` in the Blueprint
graph, just before `PrepareBuildActions`.
This enables users to use bazel query as a way to introspect the Soong
module graph. For example,
- Direct reverse dependencies of //bionic/libc:generated_android_ids in
//bionic/libc/...:
$ bazel query 'rdeps(//bionic/libc/...,
//bionic/libc:generated_android_ids, 1)'
//bionic/libc:libc_bionic_ndk--android_recovery_arm_armv7-a-neon_static
//bionic/libc:libc_bionic_ndk--android_ramdisk_arm_armv7-a-neon_static
//bionic/libc:libc_bionic_ndk--android_arm_armv7-a-neon_static_com.android.runtime
//bionic/libc:libc_bionic_ndk--android_arm_armv7-a-neon_static
//bionic/libc:generated_android_ids
- Why does com.android.runtime depend on lzma?
$ bazel query
'somepath(//bionic/apex:com.android.runtime--android_common_com.android.runtime_image,
//external/lzma/...)'
//bionic/apex:com.android.runtime--android_common_com.android.runtime_image
//bionic/libc/malloc_debug:libc_malloc_debug--android_arm_armv7-a-neon_shared_com.android.runtime
//system/core/libunwindstack:libunwindstack--android_arm_armv7-a-neon_shared_com.android.runtime
//external/lzma/C:liblzma--android_arm_armv7-a-neon_shared_com.android.runtime
- What does the dep graph of //bionic/libc:crtbegin_so look like?
$ bazel query
'deps(//bionic/libc:crtbegin_so--android_arm_armv7-a-neon)'
--output=graph > graph.in && dot -Tpng < graph.in > graph.png
https://photos.app.goo.gl/DfsdoFRNsRjGwTmy8
Test: croot && m bazel_overlay && cd out/soong/bazel_overlay && bazel
query //... && bazel query 'rdeps(//bionic/libc/...,
//bionic/libc:generated_android_ids, 1)'
Signed-off-by: Jingwen Chen <jingwen@google.com>
Change-Id: I3bf40309bfb2d963bb8a688706385a57ee304c37#
diff --git a/cmd/soong_build/Android.bp b/cmd/soong_build/Android.bp
index b559bac..7b8352b 100644
--- a/cmd/soong_build/Android.bp
+++ b/cmd/soong_build/Android.bp
@@ -26,6 +26,7 @@
srcs: [
"main.go",
"writedocs.go",
+ "bazel_overlay.go",
],
primaryBuilder: true,
}
diff --git a/cmd/soong_build/bazel_overlay.go b/cmd/soong_build/bazel_overlay.go
new file mode 100644
index 0000000..e37c163
--- /dev/null
+++ b/cmd/soong_build/bazel_overlay.go
@@ -0,0 +1,173 @@
+// Copyright 2020 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import (
+ "android/soong/android"
+ "fmt"
+ "io/ioutil"
+ "os"
+ "path/filepath"
+ "strings"
+
+ "github.com/google/blueprint"
+)
+
+const (
+ soongModuleLoad = `package(default_visibility = ["//visibility:public"])
+load("//:soong_module.bzl", "soong_module")
+`
+
+ // A BUILD file target snippet representing a Soong module
+ soongModuleTarget = `soong_module(
+ name = "%s",
+ module_name = "%s",
+ module_type = "%s",
+ module_variant = "%s",
+ deps = [
+ %s
+ ],
+)
+`
+
+ // The soong_module rule implementation in a .bzl file
+ soongModuleBzl = `
+SoongModuleInfo = provider(
+ fields = {
+ "name": "Name of module",
+ "type": "Type of module",
+ "variant": "Variant of module",
+ },
+)
+
+def _soong_module_impl(ctx):
+ return [
+ SoongModuleInfo(
+ name = ctx.attr.module_name,
+ type = ctx.attr.module_type,
+ variant = ctx.attr.module_variant,
+ ),
+ ]
+
+soong_module = rule(
+ implementation = _soong_module_impl,
+ attrs = {
+ "module_name": attr.string(mandatory = True),
+ "module_type": attr.string(mandatory = True),
+ "module_variant": attr.string(),
+ "deps": attr.label_list(providers = [SoongModuleInfo]),
+ },
+)
+`
+)
+
+func targetNameWithVariant(c *blueprint.Context, logicModule blueprint.Module) string {
+ name := ""
+ if c.ModuleSubDir(logicModule) != "" {
+ name = c.ModuleName(logicModule) + "--" + c.ModuleSubDir(logicModule)
+ } else {
+ name = c.ModuleName(logicModule)
+ }
+
+ return strings.Replace(name, "//", "", 1)
+}
+
+func qualifiedTargetLabel(c *blueprint.Context, logicModule blueprint.Module) string {
+ return "//" +
+ packagePath(c, logicModule) +
+ ":" +
+ targetNameWithVariant(c, logicModule)
+}
+
+func packagePath(c *blueprint.Context, logicModule blueprint.Module) string {
+ return filepath.Dir(c.BlueprintFile(logicModule))
+}
+
+func createBazelOverlay(ctx *android.Context, bazelOverlayDir string) error {
+ blueprintCtx := ctx.Context
+ blueprintCtx.VisitAllModules(func(module blueprint.Module) {
+ buildFile, err := buildFileForModule(blueprintCtx, module)
+ if err != nil {
+ panic(err)
+ }
+
+ // TODO(b/163018919): DirectDeps can have duplicate (module, variant)
+ // items, if the modules are added using different DependencyTag. Figure
+ // out the implications of that.
+ depLabels := map[string]bool{}
+ blueprintCtx.VisitDirectDeps(module, func(depModule blueprint.Module) {
+ depLabels[qualifiedTargetLabel(blueprintCtx, depModule)] = true
+ })
+
+ var depLabelList string
+ for depLabel, _ := range depLabels {
+ depLabelList += "\"" + depLabel + "\",\n "
+ }
+ buildFile.Write([]byte(
+ fmt.Sprintf(
+ soongModuleTarget,
+ targetNameWithVariant(blueprintCtx, module),
+ blueprintCtx.ModuleName(module),
+ blueprintCtx.ModuleType(module),
+ // misleading name, this actually returns the variant.
+ blueprintCtx.ModuleSubDir(module),
+ depLabelList)))
+ buildFile.Close()
+ })
+
+ if err := writeReadOnlyFile(bazelOverlayDir, "WORKSPACE", ""); err != nil {
+ return err
+ }
+
+ if err := writeReadOnlyFile(bazelOverlayDir, "BUILD", ""); err != nil {
+ return err
+ }
+
+ return writeReadOnlyFile(bazelOverlayDir, "soong_module.bzl", soongModuleBzl)
+}
+
+func buildFileForModule(ctx *blueprint.Context, module blueprint.Module) (*os.File, error) {
+ // Create nested directories for the BUILD file
+ dirPath := filepath.Join(bazelOverlayDir, packagePath(ctx, module))
+ if _, err := os.Stat(dirPath); os.IsNotExist(err) {
+ os.MkdirAll(dirPath, os.ModePerm)
+ }
+ // Open the file for appending, and create it if it doesn't exist
+ f, err := os.OpenFile(
+ filepath.Join(dirPath, "BUILD.bazel"),
+ os.O_APPEND|os.O_CREATE|os.O_WRONLY,
+ 0644)
+ if err != nil {
+ return nil, err
+ }
+
+ // If the file is empty, add the load statement for the `soong_module` rule
+ fi, err := f.Stat()
+ if err != nil {
+ return nil, err
+ }
+ if fi.Size() == 0 {
+ f.Write([]byte(soongModuleLoad + "\n"))
+ }
+
+ return f, nil
+}
+
+// The overlay directory should be read-only, sufficient for bazel query.
+func writeReadOnlyFile(dir string, baseName string, content string) error {
+ workspaceFile := filepath.Join(bazelOverlayDir, baseName)
+ // 0444 is read-only
+ return ioutil.WriteFile(workspaceFile, []byte(content), 0444)
+}
diff --git a/cmd/soong_build/main.go b/cmd/soong_build/main.go
index 532d9e4..01a39a2 100644
--- a/cmd/soong_build/main.go
+++ b/cmd/soong_build/main.go
@@ -26,11 +26,13 @@
)
var (
- docFile string
+ docFile string
+ bazelOverlayDir string
)
func init() {
flag.StringVar(&docFile, "soong_docs", "", "build documentation file to output")
+ flag.StringVar(&bazelOverlayDir, "bazel_overlay_dir", "", "path to the bazel overlay directory")
}
func newNameResolver(config android.Config) *android.NameResolver {
@@ -65,7 +67,7 @@
os.Exit(1)
}
- if docFile != "" {
+ if !shouldPrepareBuildActions() {
configuration.SetStopBefore(bootstrap.StopBeforePrepareBuildActions)
}
@@ -85,6 +87,13 @@
bootstrap.Main(ctx.Context, configuration, extraNinjaDeps...)
+ if bazelOverlayDir != "" {
+ if err := createBazelOverlay(ctx, bazelOverlayDir); err != nil {
+ fmt.Fprintf(os.Stderr, "%s", err)
+ os.Exit(1)
+ }
+ }
+
if docFile != "" {
if err := writeDocs(ctx, docFile); err != nil {
fmt.Fprintf(os.Stderr, "%s", err)
@@ -94,7 +103,7 @@
// TODO(ccross): make this a command line argument. Requires plumbing through blueprint
// to affect the command line of the primary builder.
- if docFile == "" {
+ if shouldPrepareBuildActions() {
metricsFile := filepath.Join(bootstrap.BuildDir, "soong_build_metrics.pb")
err = android.WriteMetrics(configuration, metricsFile)
if err != nil {
@@ -103,3 +112,9 @@
}
}
}
+
+func shouldPrepareBuildActions() bool {
+ // If we're writing soong_docs or bazel_overlay, don't write build.ninja or
+ // collect metrics.
+ return docFile == "" && bazelOverlayDir == ""
+}