| commit | ab0b7e0c43b1f64d0feaf411f792430aef8d148f | [log] [tgz] |
|---|---|---|
| author | Mathias Rav <mathiasr@google.com> | Thu May 24 09:54:41 2018 +0200 |
| committer | Mathias Rav <mathiasr@google.com> | Thu May 24 09:54:41 2018 +0200 |
| tree | 856dc90094289e41f119abb160b5a00a50d36b48 | |
| parent | 3726e35942658a60e9e9549dc95d62590c9eade7 [diff] |
Outliner: Don't use mutable keys in HashMap The Outline type (used by Outliner to represent outlining candidates) is mutable since it stores references to IR instructions belonging to particular methods. As a result, the Outline type can change its mapping identity when R8 optimizations determine that an instruction's out-value can be set to null (which happens e.g. on all StringBuilder and StringBuffer methods that are known to return `this`). When Outline is used as the key type in a HashMap, the map must not stay around long enough for the Outline keys to change their mapping identities in this way. Change Outliner from keeping a Map<Outline, List<DexEncodedMethod>> as its outlining candidates to simply List<List<DexEncodedMethod>>, one method list per Outline. The Outliner should not assume that when converting IRCode x to CF/DEX and back to an IRCode y, the set of outlines spotted in x is equal to the set of outlines spotted in y. Instead, outlining should be performed in three phases: First, when all methods are converted to IR as part of normal processing, outlines are spotted to identify methods containing frequently-occurring outline sites. Second, the identified methods are converted back to IR to identify the actually-frequent outlines. Third, the outline support class is generated and the actually-frequent outlines are outlined. Note that the IR constructed in the second step is thrown away in order to ensure that the same set of outlines are spotted in the second and third steps. Change-Id: I665b041a04d3c7fee392c3a0a3b5cccb093d9cad
The 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.