hat-01-03-building-hat-with-maven.md

Building HAT

---

• Contents
• House Keeping
  • Project Layout
  • Building Babylon
  • Building HAT
• Programming Model
  • Programming Model
• Interface Mapping
  • Interface Mapping Overview
  • Cascade Interface Mapping
• Implementation Detail
  • Walkthrough Of Accelerator.compute()
  • How we minimize buffer transfers

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Building HAT

We can build HAT using maven and cmake.

Maven controls the build but delegates to cmake for native artifacts (such as various backends).

Note: You should not edit the pom.xml files, these are autogenerated (using mkpoms) and your changes will get overwritten.

Setting environment variables JAVA_HOME and PATH

To build HAT we need to ensure that JAVA_HOME is set to point to our babylon jdk (the one we built here)

It will simplify our tasks going forward if we add ${JAVA_HOME}/bin to our PATH (before any other JAVA installs).

The env.bash shell script can be sourced (dot included) in your shell to set JAVA_HOME and PATH

It should detect the arch type (AARCH64 or X86_46) and select the correct relative parent dir and inject that dir in your PATH.

You will need jextract for your platform, and the jextract/bin dir should also be in your path.

cd hat
. ./env.bash
export PATH=${PATH}:/path/to/my/jextract/bin
echo ${JAVA_HOME}
/Users/ME/github/babylon/hat/../build/macosx-aarch64-server-release/jdk
echo ${PATH}
/Users/ME/github/babylon/hat/../build/macosx-aarch64-server-release/jdk/bin:/usr/local/bin:......

Root level maven pom.xml properties

If you followed the instructions for building babylon your pom.xml properties should look like this, and should not need changing

<project>
    <!-- yada -->
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <hat.build>${env.PWD}/build</hat.build>
    </properties>
    <!-- yada -->
</project>

Sanity checking your env and root pom.xml

After sourcing env.bash or making changes to pom.xml we can sanity check our setup by running

cd hat
java @bldr/sanity

Building with maven

Now we should be able to use maven to build, if successful maven will place all jars and libs in a newly created build dir in your top level hat dir.

cd hat
. ./env.bash
mvn clean  compile package install
ls build
hat-1.0.jar                         hat-example-heal-1.0.jar        libptx_backend.dylib
hat-backend-ffi-cuda-1.0.jar        hat-example-mandel-1.0.jar      libspirv_backend.dylib
hat-backend-ffi-mock-1.0.jar        hat-example-squares-1.0.jar     mock_info
hat-backend-ffi-opencl-1.0.jar      hat-example-view-1.0.jar        opencl_info
hat-backend-ffi-ptx-1.0.jar         hat-example-violajones-1.0.jar  ptx_info
hat-backend-ffi-spirv-1.0.jar       libmock_backend.dylib           spirv_info
hat-example-experiments-1.0.jar     libopencl_backend.dylib

The provided maven-build.bash script contains the minimal maven commandline

bash maven-build.bash

Running an example

To run an example we use the maven artifacts in build

${JAVA_HOME}/bin/java \
   --enable-preview --enable-native-access=ALL-UNNAMED \
   --class-path build/hat-1.0.jar:build/hat-example-mandel-1.0.jar:build/hat-backend-ffi-opencl-1.0.jar \
   --add-exports=java.base/jdk.internal=ALL-UNNAMED \
   -Djava.library.path=build\
   mandel.Main

The provided hat/run java launch script simplifies this somewhat, we just need to pass the backend name ffi-opencl and the package name mandel (all examples are assumed to be in packagename/Main.java

java @hat/run ffi-opencl mandel