Introduction

The Platform-Neutral Compute Intermediate Language, or PENCIL, is a C99-based language developed as part of the CARP Project. A key goal of the language is to serve as an intermediate language for the compilation of domain-specific languages. The PENCIL representation can then be compiled into efficient, device-specific OpenCL code using a PENCIL-to-OpenCL compiler such as PPCG. This eliminates the need for the DSL implementer to develop different platform-specific backends: all that is needed to target different platforms is a PENCIL backend!

The PENCIL Scala library

The PENCIL repository contains a Scala library that can be used to implement a PENCIL backend for a DSL compiler. The library provides the following:

• An in-memory representation of the PENCIL as a set of Scala classes.
• Validation functions for the in-memory PENCIL representation.
• A printer to obtain PENCIL code from the in-memory representation.

This library significantly simplifies the development process of targeting a DSL to PENCIL, by providing an API for building, manipulating, and printing the PENCIL intermediate representation.

Using the PENCIL Scala library

• Download the library:

  git clone git@github.com:carpproject/pencil.git

• Build the library following the instructions in the README.txt file
• To use the library, add the pencil.jar file to your CLASSPATH:

  export CLASSPATH=$CLASSPATH:${PENCIL_CLONE}/pencil.jar
  

• There is an example demonstrating the PENCIL library usage: github This example can also be found in the example directory in the PENCIL library repository.

Useful links

• VOBLA: a DSL for linear algebra targeting PENCIL: github
• PENCIL IR internal documentation: doxygen
• PENCIL to CUDA/OpenCL compiler: PPCG