Change register allocator to deal better with unconstrained uses.

When low on registers, if the interval we are currently attempting
to allocate a register for has an unconstrained first use, split
the current interval instead of finding another interval to split.

In addition, make the determination of when to split argument
values right after their definition more precise.

These changes shouldn't matter much at this point. However,
zerny@ is working on changes to debug information handling
that will make this occur a lot more for arguments. For such
cases this is needed and generates better code than we currently
do.

R=zerny@google.com

Change-Id: I6d83b91a15486d294c2c66f68b17cb871c0cbae1
3 files changed
tree: 75a402517e04749a54cb903cb97c53b9cff8e30e
  1. buildSrc/
  2. scripts/
  3. src/
  4. tests/
  5. third_party/
  6. tools/
  7. .gitignore
  8. AUTHORS
  9. build.gradle
  10. codereview.settings
  11. CONTRIBUTING.md
  12. copyAdditionalJctfCommonFiles.gradle
  13. LICENSE
  14. README.md
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.

Testing

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.

Getting help

For questions, bug reports and other issues reach out to us at r8-dev@googlegroups.com.