Snap for 7325276 from 1b18efe53304a3c3d7112e91250b885ed5437a9e to sc-release
Change-Id: Ibfc95196c6f0ea40b4ee1f8629345dc105882e4c
diff --git a/split/README.md b/split/README.md
new file mode 100644
index 0000000..db3e7de
--- /dev/null
+++ b/split/README.md
@@ -0,0 +1,107 @@
+# Manifest Split
+
+## Overview
+
+Split manifests are Android repo manifests that contain the minimum set of
+projects necessary to build a given target. If a project isn't used for building
+the target, it shouldn't be in the split manifest. This smaller manifest can be
+used to sync the Android source tree and build the specific target. This sync
+should be faster and smaller than a sync of a full manifest because it is
+syncing less projects.
+
+The `treble_manifest_split` tool is used to automatically create a split
+manifest from a full manifest using dependency information from the source tree
+and the build outputs. The tool attempts to infer as many dependencies as it
+can, but some will be missed due to implicit dependencies in the build system
+and source tree. This is solved by manually fine-tuning a tool configuration XML
+specific to your target.
+
+## Example for aosp_arm64
+
+### 1. Run a full build using a full manifest
+
+The `treble_manifest_split` tool needs the ninja build graph and deps log from a
+completed build in order to have a full view of the dependency graph. While the
+build graph is created at the beginning of a ninja build, the deps log is not
+complete until the build finishes.
+
+Use standard Android build commands to build your target.
+
+### 2. Use the treble_manifest_split tool
+
+```shell
+# Change to the directory where you ran the full build.
+cd /path/to/android
+
+# Set command line variables for the Android target you are using and the build
+# target that should be buildable from your split manifest.
+ANDROID_TARGET=aosp_arm64-userdebug
+BUILD_TARGET=droid
+
+# Build treble_manifest_split as a python binary.
+lunch $ANDROID_TARGET
+m treble_manifest_split
+
+# Create the split manifest using a sample config XML specific to aosp_arm64.
+out/host/linux-x86/bin/treble_manifest_split \
+ --manifest .repo/manifests/default.xml \
+ --split-manifest split_default.xml \
+ --debug-file debug.json \
+ --config tools/treble/split/sample_config.xml \
+ $BUILD_TARGET
+```
+
+### 3. Build using the split manifest
+
+You should test that the split manifest created by the tool can be used to build
+the partial target files package.
+
+1. Initialize a new repo directory using the steps in
+ https://source.android.com/setup/build/downloading#initializing-a-repo-client.
+1. Replace the `.repo/manifests/default.xml` full manifest with the
+ newly-generated split manifest.
+1. Use standard `repo sync` commands to sync your repo.
+1. Attempt a build of your target.
+
+### 4. Fix build errors
+
+Build errors may arise due to missing dependencies that were previously provided
+by now-removed projects. These dependencies may be implicit in the source code,
+or an explicit dependency type that is not yet able to be automatically detected
+by the tool.
+
+1. Find the dependency source project in your full-manifest repo directory.
+1. Update your config XML to manually add projects to your split manifest.
+
+ - For example, the following line in `sample_config.xml` in this tool
+ directory specifies a project that should be included in the split
+ manifest even if the tool doesn't automatically detect that it is
+ necessary.
+
+ ```
+ <add_project name="platform/external/python/cpython3" />
+ ```
+
+1. Regenerate the split manifest using `treble_manifest_split` in your
+ full-manifest directory. Remember to pass the path of your config XML to the
+ script's `--config` flag.
+
+### 5. Compare built artifacts
+
+A successful build alone is not sufficient to have full confidence in the split
+manifest. You should diff the output artifacts of the split-manifest build
+against the output artifacts of the full-manifest build.
+
+Suggestions for viewing diffs:
+
+- Use an external directory diffing tool on the output directories for each
+ partition, such as `out/target/product/<device>/system`.
+- Use `development/vndk/tools/image-diff-tool/diff.py` on output directories,
+ or on a zipped target-files archive if you are creating `dist` builds.
+
+The following may cause differences between output artifacts:
+
+- Non-hermetic inputs used in the module build rule, such as timestamps. Can
+ be fixed by removing the timestamp from the build rule.
+- An implicit and optional source dependency. Can be fixed by manually adding
+ the project that defines the missing source.
diff --git a/split/manifest_split.py b/split/manifest_split.py
index f329958..d5f9b95 100644
--- a/split/manifest_split.py
+++ b/split/manifest_split.py
@@ -619,7 +619,7 @@
repo_list_file = None
ninja_build_file = None
module_info_file = None
- ninja_binary = "ninja"
+ ninja_binary = "prebuilts/build-tools/linux-x86/bin/ninja"
kati_stamp_file = None
overlays = []
installed_prebuilts = []
diff --git a/split/sample_config.xml b/split/sample_config.xml
new file mode 100644
index 0000000..b9318ff
--- /dev/null
+++ b/split/sample_config.xml
@@ -0,0 +1,33 @@
+<?xml version="1.0" encoding="utf-8"?>
+<config>
+ <!-- treble_manifest_split config for aosp_arm64. -->
+
+ <!-- ============================================================= -->
+
+ <!-- Add projects that provide modules required for build success, but
+ are not detected automatically by the tool. -->
+
+ <!-- Lots of modules require py3-stdlib -->
+ <add_project name="platform/external/python/cpython3" />
+
+ <!-- bionic/libc:libc_jemalloc_wrapper requires libjemalloc5 -->
+ <add_project name="platform/external/jemalloc_new" />
+
+ <!-- libcore/ojluni:ojluni-phony requires art-notices-for-framework-stubs-jar -->
+ <add_project name="platform/prebuilts/module_sdk/art" />
+
+ <!-- Provides executable "as", needed by clang for some modules. -->
+ <add_project name="platform/prebuilts/gcc/linux-x86/arm/arm-linux-androideabi-4.9" />
+
+ <!-- ============================================================= -->
+
+ <!-- Remove some device projects that the tool included due to Kati makefile
+ scanning, but are not required to build aosp_arm64. -->
+ <remove_project name="device/generic/goldfish" />
+ <remove_project name="device/generic/goldfish-opengl" />
+ <remove_project name="device/google/atv" />
+ <remove_project name="device/google/trout" />
+ <remove_project name="device/ti/beagle-x15" />
+
+</config>
+
