Version 1.4.29

Cherry-pick: Fix not setting offset on DexItemBasedConstString replacement
CL: https://r8-review.googlesource.com/c/r8/+/33145

Cherry-pick: Add test for gms core with forced jumbo string rewriting
CL: https://r8-review.googlesource.com/c/r8/+/33228

Cherry-pick: Don't generate compat rules when tracing reflective use
CL: https://r8-review.googlesource.com/c/r8/+/32845

Cherry-pick: Mark fields accessed by reflection as both read and written
CL: https://r8-review.googlesource.com/c/r8/+/33271

Cherry-pick: Print proper reason for kept-by-reflection edges.
CL: https://r8-review.googlesource.com/c/r8/+/33263

Cherry-pick: Ensure that we can merge desugared java8 classes
CL: https://r8-review.googlesource.com/c/r8/+/33281

Cherry-pick: Add support for -libraryjars in ProguardTestBuilder.
CL: https://r8-review.googlesource.com/c/r8/+/33274

Cherry-pick: Throw for unimplemented APIs in ProguardTestBuilder
CL: https://r8-review.googlesource.com/c/r8/+/33262

Cherry-pick: Guard check-cast elimination when in-value is null constant
CL: https://r8-review.googlesource.com/c/r8/+/33300

Cherry-pick: Revert "Revert "Assert that definitionFor is only called on non-null class types.""
CL: https://r8-review.googlesource.com/c/r8/+/33280

Bug: 123152027
Bug: 123242448
Bug: 123215165
Bug: 69590587
Bug: 123164442
Bug: 123269162
Change-Id: I06db0b137ceb3d3410f04680c5bbecc697b8f905
38 files changed
tree: 41521fdc2ffca0d93ca94f314f7927b8314beeab
  1. buildSrc/
  2. library-licensing/
  3. scripts/
  4. src/
  5. tests/
  6. third_party/
  7. tools/
  8. .gitignore
  10. build.gradle
  11. codereview.settings
  13. copyAdditionalJctfCommonFiles.gradle
  16. PRESUBMIT.py
  17. README.md

D8 dexer and R8 shrinker

The R8 repo contains two tools:

  • D8 is a dexer that converts java byte code to dex code.
  • R8 is a java program shrinking and minification tool that converts java byte code to optimized dex code.

D8 is a replacement for the DX dexer and R8 is a replacement for the Proguard shrinking and minification tool.

Downloading and building

The R8 project uses depot_tools from the chromium project to manage dependencies. Install depot_tools and add it to your path before proceeding.

The R8 project uses Java 8 language features and requires a Java 8 compiler and runtime system.

Typical steps to download and build:

$ git clone https://r8.googlesource.com/r8
$ cd r8
$ tools/gradle.py d8 r8

The tools/gradle.py script will bootstrap using depot_tools to download a version of gradle to use for building on the first run. This will produce two jar files: build/libs/d8.jar and build/libs/r8.jar.

Running D8

The D8 dexer has a simple command-line interface with only a few options.

The most important option is whether to build in debug or release mode. Debug is the default mode and includes debugging information in the resulting dex files. Debugging information contains information about local variables used when debugging dex code. This information is not useful when shipping final Android apps to users and therefore, final builds should use the --release flag to remove this debugging information to produce smaller dex files.

Typical invocations of D8 to produce dex file(s) in the out directoy:

Debug mode build:

$ java -jar build/libs/d8.jar --output out input.jar

Release mode build:

$ java -jar build/libs/d8.jar --release --output out input.jar

The full set of D8 options can be obtained by running the command line tool with the --help option.

Running R8

R8 is a Proguard replacement for whole-program optimization, shrinking and minification. R8 uses the Proguard keep rule format for specifying the entry points for an application.

Typical invocations of R8 to produce optimized dex file(s) in the out directory:

$ java -jar build/libs/r8.jar --release --output out --pg-conf proguard.cfg input.jar

The full set of R8 options can be obtained by running the command line tool with the --help option.


Typical steps to run tests:

$ tools/test.py --no_internal

The tools/test.py script will use depot_tools to download a lot of tests and test dependencies on the first run. This includes prebuilt version of the art runtime on which to validate the produced dex code.


In order to contribute to D8/R8 you have to sign the Contributor License Agreement. If your contribution is owned by your employer you need the Corporate Contributor License Agreement.

Once the license agreement is in place, you can upload your patches using ‘git cl’ which is available in depot_tools. Once you have a change that you are happy with you should make sure that it passes all tests and then upload the change to our code review tool using:

$ git cl upload

On your first upload you will be asked to acquire credentials. Follow the instructions given by git cl upload.

On successful uploads a link to the code review is printed in the output of the upload command. In the code review tool you can assign reviewers and mark the change ready for review. At that point the code review tool will send emails to reviewers.

Getting help

For questions, reach out to us at r8-dev@googlegroups.com.

For D8, find known issues in the D8 issue tracker or file a new D8 bug report.

For R8, find known issues in the R8 issue tracker or file a new R8 bug report.