PLOMO2: A new generation of tools to navigate and profile programs

An INRIA Equipe Associee between RMOD and PLEIAD, a continuation of the PLOMO Equipe Associee named after cerro El Plomo, the highest peak (5424 meters) that is visible from Santiago. Foto by by Thiago "James".

Performing effective software development and maintenance are best achieved with effective tool support. Provided by a variety of tools, each one presenting a specific kind of information supporting the task at hand. The goal of the first PLOMO was to develop new meta tools to improve and bring synergy in the existing infrastructure of Pharo (for software development) and the Moose software analysis platform (for maintenance). With Plomo2, we want to build on top of this work and invent a new generation tools to navigate and profile programs.

The hypotheses that Plomo2 will seek to verify are:

• Use of reflection enables new profiling techniques
• Use of visualization in a programming environment improves programmer performance

The overall objectives of Plomo2 are:

1. Infrastructure for profiling programs and recording programmer activity.
2. Visual software maps defined in a flexible and agile fashion
3. Combining dynamic information with visualization to improve the development environment
4. Empirical evaluation of this environment

All the efforts will be performed on Pharo and Moose, two platforms heavily used by the RMoD and Pleiad teams.

For both for program profiling and programmer activity recording, we need a way to deeply hook into the system. We plan for this to improve the reflective infrastructure of Pharo.

During the previous period we worked on OPAL, a new compiler toolchain for Pharo. In essence the work on the compiler framework does not move forward the state of the art in compiler technology. However it has already been proven to be a crucial building block. It provided the fundamentals for many research experiments and new features for Pharo. For example, Pleiad and RMoD collaborated on a novel type system for Pharo that was realized using the new compiler infrastructure. Other examples are the many new features of Pharo 3 that use parts of the new compiler chain, like AST-based navigation in the editor or breakpoints.

The Opal flexible compiler infrastructure will allow us to build a new generation of reflective infrastructure. Such infrastructure is keys to support tools (profilers) and new language design (AOP, proxies, isolation). We are now in a position to perform a new iteration on the reflective layer and metaobject protocol for Pharo. In 2005 we started to develop new reflective foundations and we learned a lot (partial reflection, metalevel recursion handling, object-centric on the fly propagation, proxies, isolation). We are now in a situation to step back and redesign the reflective layer based on all the cases we identified and developed.

The results of this work package will be used and thus validated by WP3. In addition, we plan to realize the next generation of the AOP framework Phantom using the reflection framework. This especially makes sure that the framework is general and not just limited for the use in tools.

Plomo made a lot of progress by realizing the Roassal visualisation framework. We plan to enhance the infrastructure to visually render software-related data. We will investigate two complementary directions:

1. Interaction and scalability in Roassal 2D. Roassal is an Agile Visualization Engine that offers large range of options to make the user interact with the visualization. Visualization software require particular customizations to cope with large amount of data. Navigation should support interactive and semantic zooming, which is an essential feature for navigating large amount of data elements. Additional layers, including drawing dependency matrices, vectorial and interactive charts are required
2. Visual representation of 3D environment gives a sensation of immersion that is often key to identify some patterns in a data structure. Current programming environments exploiting 3D are either fixed to a particular representation or unfit to be used as the base of a programming environment

The goal of the third work package is to build on top of both WP1 and WP2: Combining dynamic information with visualization to improve the development environment.

1. Visualization to navigate and browse source code – System complexity is a polymetric view efficient at representing class hierarchies in a software source code. It has been shown that system complexity is effective for software maintenance. We will augment the range of application of it by using it to navigate and browser application source code.
2. Visualizing dynamic information to navigate source code. The static view of code should be enhanced with dynamic information gathered from program execution. A good example here is visualization of profiling and tracing information.
3. Context based on history – It has been shown that analyzing past user actions may precisely infer what will be the next user actions. Unfortunately, history is poorly supported in traditional programming environment. Making history a first class element in the programming environment is the topic of this work package.

This work package will therefore validate both WP1 and WP2. We will validate the ideas developed as part of WP3 by carrying out an empirical evaluation.