MicroVM Reference Implementation

This project is outdated. Please use the microvm-refimpl2.

This is the previous reference implementation of MicroVM. It implements the specification in https://github.com/microvm/microvm-spec-legacy/wiki

MicroVM, a.k.a. µVM, or uvm, is a low-level virtual machine designed to support high-level programming languages. It is designed to provide concurrency, JIT compiling and garbage collection as its core functions while keeping the VM itself minimal. The purpose of this reference implementation, however, is to demonstrate its interface to its client, which is the program that compiles high-level language programs to the MicroVM intermediate representation.

Implementation Details

Given the purpose of demonstrating the interface, this MicroVM is not implemented efficiently and realistically as a productional virtual machine. It produces the desired computation results expected from a productional VM, but there are some limitations:

• This implementation is written in the Java programming language and runs on the Hotspot JVM.
• It assumes 64-bit x86-64 architecture.
• This implementation uses green threads. MicroVM threads and MicroVM stacks can be created in the desired way as the interface specifies, but only one thread is running at any moment.
• The execution is done by interpreting rather than JIT compiling.
• It has a single-threaded stop-the-world garbage collector. It has a simplistic Immix-like mark-region GC for small objects and a mark-sweep GC for large objects.

Building and Running

This reference implementation is written in the Java programming language. It is recommended to use the Eclipse IDE.

This project depends on the sun.misc.Unsafe class for raw memory access. You should use the Hotspot JVM.

It uses the Antlr parser generator for the MicroVM Intermediate Representation parser. Antlr 4.2 is bundled in this project. To generate the parser, you should install Ant and invoke:

ant build-uir-parser

Then the project should compile. The source code is in the src directory and the generated parser is in the parser-generated directory.

Currently it still needs to know some implementation details about the MicroVM to use it. There are many test cases in the test directory, especially the uvm.refimpl.TestMicroVMRefImpl test suite. Please have a look at the source code.

Authors

This project is created by Kunshan Wang, Yi Lin, Steve Blackburn, Antony Hosking, Michael Norrish. See the LICENSE file for the licence.

Contact

Kunshan Wang [email protected]