Section: New Results

Tailoring Applications and boostrapping

Virtualization Support for Dynamic Core Library Update. Dynamically updating language runtime and core libraries such as collections and threading is challenging since the update mechanism uses such libraries at the same time that it modifies them. To tackle this challenge, we present Dynamic Core Library Update (DCU) as an extension of Dynamic Software Update (DSU) and our approach based on a virtualization architecture. Our solution supports the update of core libraries as any other normal library, avoiding the circular dependencies between the updater and the core libraries. Our benchmarks show that there is no evident performance overhead in comparison with a default execution. Finally, we show that our approach can be applied to real life scenario by introducing a critical update inside a web application with 20 simulated concurrent users. [34]

Bootstrapping Infrastructure. Bootstrapping is well known in the context of compilers, where a bootstrapped compiler can compile its own source code. Bootstrapping is a beneficial engineering practice because it raises the level of abstraction of a program making it easier to understand, optimize, evolve, etc. Bootstrapping a reflective object-oriented language is however more challenging , as we need also to initialize the runtime of the language with its initial objects and classes besides writing its compiler. We present a novel bootstrapping infrastructure for Pharo-like languages that allows us to easily extend and modify such languages. Our bootstrapping process relies on a first-class runtime. A first-class runtime is a meta-object that represents a program's runtime and provides a MOP to easily load code into it and manipulate its objects. It decou-ples the virtual machine (VM) and language concerns by introducing a clear VM-language interface. Using this process, we show how we succeeded to bootstrap a Smalltalk-based language named Candle and then extend it with traits in less than 250 lines of high-level Smalltalk code. We also show how we can bootstrap with minimal effort two other languages (Pharo and MetaTalk) with similar execution semantics but different object models. [35]