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/android/bazel_overlay.go b/android/bazel_overlay.go
new file mode 100644
index 0000000..a034282
--- /dev/null
+++ b/android/bazel_overlay.go
@@ -0,0 +1,76 @@
+// 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 android
+
+import (
+ "fmt"
+ "os"
+ "strings"
+
+ "github.com/google/blueprint"
+)
+
+// The Bazel Overlay singleton is responsible for generating the Ninja actions
+// for calling the soong_build primary builder in the main build.ninja file.
+func init() {
+ RegisterSingletonType("bazel_overlay", BazelOverlaySingleton)
+}
+
+func BazelOverlaySingleton() Singleton {
+ return &bazelOverlaySingleton{}
+}
+
+type bazelOverlaySingleton struct{}
+
+func (c *bazelOverlaySingleton) GenerateBuildActions(ctx SingletonContext) {
+ // Create a build and rule statement, using the Bazel overlay's WORKSPACE
+ // file as the output file marker.
+ var deps Paths
+ moduleListFilePath := pathForBuildToolDep(ctx, ctx.Config().moduleListFile)
+ deps = append(deps, moduleListFilePath)
+ deps = append(deps, pathForBuildToolDep(ctx, ctx.Config().ProductVariablesFileName))
+
+ bazelOverlayDirectory := PathForOutput(ctx, "bazel_overlay")
+ bazelOverlayWorkspaceFile := bazelOverlayDirectory.Join(ctx, "WORKSPACE")
+ primaryBuilder := primaryBuilderPath(ctx)
+ bazelOverlay := ctx.Rule(pctx, "bazelOverlay",
+ blueprint.RuleParams{
+ Command: fmt.Sprintf(
+ "rm -rf ${outDir}/* && %s --bazel_overlay_dir ${outDir} %s && echo WORKSPACE: `cat %s` > ${outDir}/.overlay-depfile.d",
+ primaryBuilder.String(),
+ strings.Join(os.Args[1:], " "),
+ moduleListFilePath.String(), // Use the contents of Android.bp.list as the depfile.
+ ),
+ CommandDeps: []string{primaryBuilder.String()},
+ Description: fmt.Sprintf(
+ "Creating the Bazel overlay workspace with %s at $outDir",
+ primaryBuilder.Base()),
+ Deps: blueprint.DepsGCC,
+ Depfile: "${outDir}/.overlay-depfile.d",
+ },
+ "outDir")
+
+ ctx.Build(pctx, BuildParams{
+ Rule: bazelOverlay,
+ Output: bazelOverlayWorkspaceFile,
+ Inputs: deps,
+ Args: map[string]string{
+ "outDir": bazelOverlayDirectory.String(),
+ },
+ })
+
+ // Add a phony target for building the bazel overlay
+ ctx.Phony("bazel_overlay", bazelOverlayWorkspaceFile)
+}