Testing JIT compilation and runtime specialization in MoarVM

Description

Currently, MoarVM is tested indirectly via the NQP and Rakudo test suites. This is not necessarily sufficient to test the spesh and JIT subsystems of MoarVM, because these:

• operate only on very active code, which is rare in short-running tests
• work on an asynchronous thread, which makes this (somewhat) unpredictable
• are many layers removed from the code-as-written (separated by the rakudo/nqp bytecode compiler and static optimizer)

Yet these are highly complex subsystems with strict correctness requirements. Therefore we need a system to test these directly.

Expected outcomes

A successful project will deliver:

• A tool to execute test cases for spesh and the JIT compiler. This tool should read a test case and directly build a suitable IR representation of the code to be processed.
• A few example test cases that exercise this system.

Required skills

A student with skills in C programming and a working understanding of virtual machines and compilers should have a good chance of succeeding.

Rating

Medium/hard

Possible mentors

Bart Wiegmans (bartwiegmans@gmail.com)