Graal is a dynamic compiler written in Java that integrates with the HotSpot JVM. It has a focus on high performance and extensibility. In addition, it provides optimized performance for Truffle based languages running on the JVM.

Setup

Working with Graal will mean cloning more than one repository and so it's recommended to create and use a separate directory:

mkdir graal
cd graal

Building Graal

To simplify Graal development, a separate Python tool called mx has been co-developed. This tool must be downloaded and put onto your PATH:

git clone https://github.com/graalvm/mx.git
export PATH=$PWD/mx:$PATH

Graal depends on a JDK that supports JVMCI (JVM Compiler Interface). Graal works with build 143 or later of a JDK9 Early Access Release. JVMCI enabled builds of JDK8 for selected platforms are available via OTN. If you are not on one of these platforms (e.g., Windows), see Building JVMCI JDK8 below.

Once you have installed (or built) a JVMCI JDK, ensure JAVA_HOME is pointing at the JDK home directory (or at <jdk_home>/Contents/Home on Mac OS X if the JDK has this layout).

Graal also depends on Truffle which needs to be cloned along with Graal.

git clone https://github.com/graalvm/graal-core.git
cd graal-core
mx

The mx command ensures a Truffle version in sync with Graal is cloned as a sibling of the graal-core directory. Changing to the graal-core directory informs mx that the focus of development (called the primary suite) is Graal. All subsequent mx commands should be executed from this directory.

After pulling subsequent Graal changes, the mx sforceimports command should be run to bring the Truffle dependency up to date.

Here's the recipe for building and running the GraalVM (If on Windows, replace mx with mx.cmd):

mx build
mx vm

By default, Graal is only used for hosted compilation (i.e., the VM still uses C2 for compilation). To make the VM use Graal as the top tier JIT compiler, add the -XX:+UseJVMCICompiler option to the command line. To disable use of Graal altogether, use -XX:-EnableJVMCI.

IDE Configuration

You can generate IDE project configurations by running:

mx ideinit

This will generate Eclipse, IntelliJ, and NetBeans project configurations. Further information on how to import these project configurations into individual IDEs can be found on the IDEs page.

The Graal code base includes the Ideal Graph Visualizer which is very useful in terms of visualizing Graal's intermediate representation (IR). You can get a quick insight into this tool by running the commands below. The first command launches the tool and the second runs one of the unit tests included in the Graal code base with extra options to make Graal output the IR for all methods it compiles to the tool. You should wait for the GUI to appear before running the second command.

mx igv &
mx unittest -Dgraal.Dump BC_athrow0

If you added -XX:+UseJVMCICompiler as described above, you will see IR for compilations requested by the VM itself in addition to compilations requested by the unit test. The former are those with a prefix in the UI denoting the compiler thread and id of the compilation (e.g., JVMCI CompilerThread0:390).

The first time you run mx igv, the Ideal Graph Visualizer will be transparently built. This only works if ant has internet access because it needs to download the NetBeans platform packages. You therefore have to configure ant to use proxies if necessary (e.g., set ANT_ARGS=-autoproxy in your environment).

Further information can be found on the Debugging page.

Publications and Presentations

For video tutorials, presentations and publications on Graal visit the Publications page.

Building JVMCI JDK8

To create a JVMCI enabled JDK8 on other platforms (e.g., Windows):

hg clone http://hg.openjdk.java.net/graal/graal-jvmci-8
cd graal-jvmci-8
mx --java-home /path/to/jdk8u111 build
export JAVA_HOME=$(mx --java-home /path/to/jdk8u111 jdkhome)

You need to use exactly version 8u111 as the bootstrap JDK in the mx --java-home ... build command. The build step above should work on all supported JDK 8 build platforms. It should also work on other platforms (such as Oracle Linux, CentOS and Fedora as described here). If you run into build problems, send a message to the Graal mailing list.