| commit | 430740d2175f8379ae28bad2c2fd56b27c0a7efa | [log] [tgz] |
|---|---|---|
| author | Søren Gjesse <sgjesse@google.com> | Thu Jan 10 16:49:42 2019 +0100 |
| committer | Søren Gjesse <sgjesse@google.com> | Thu Jan 10 16:49:42 2019 +0100 |
| tree | 21742cdb31e3329bcee2ba2d5022340500414743 | |
| parent | 7ee4ca7121598908c8f16be87a0871be3a54c056 [diff] |
Synthesize -assumevalue rule automatically based on min sdk
If there are no Proguard rules in the input configuration matching
the field
public static final int android.os.Build$VERSION.SDK_INT
R8 will synthesize the following -assumevalues rule from the
min sdk passed to the compilation:
-assumevalues public class android.os.Build$VERSION {
public static int SDK_INT return <min sdk>..2147483647;
}
This will remove effectively dead code that is guarded by explicit
checks on the SDK_INT value.
Bug: 110178672
Change-Id: Ib3b0d969ed5d49d22f9fe48b8c84f6b2d79c0c20The R8 repo contains two tools:
D8 is a replacement for the DX dexer and R8 is a replacement for the Proguard shrinking and minification tool.
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.
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.
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.
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.