Section: New Software and Platforms

Introduction

This section lists and briefly describes the software developments conducted within Compsys. Most are tools that we extend and maintain over the years. They mainly concern three activities: a) the development of research tools, in general available on demand, linked to polyhedra and loop/array transformations, b) the development of tools linked to the start-up XtremLogic (mostly done outside Compsys but partly inspired by work from Compsys), and c) the development of algorithms in the context of our collaborations with STMicroelectronics. These last developments have been stopped right now, since the end of the Mediacom project in 2012. They are described in previous Compsys activity reports: they concerned register allocation, SSA deconstruction, liveness analysis, intermediate representations, etc. They were done within the compilers of STMicroelectronics, not as stand-alone tools, so they are not available as the other tools.

Concerning tools based on a polyhedral representation of nested loops, many of them are now available. They have been developed and maintained over the years by different teams, after the introduction of Paul Feautrier's Pip, a tool for parametric integer linear programming. This “polyhedral model” view of codes is now widely accepted: it was or is used by Cairn, Parkas, and Camus Inria project-teams, PIPS at École des Mines de Paris, Suif from Stanford University, Compaan at Berkeley and Leiden, PiCo from the HP-Labs (continued as PicoExpress by Synfora and now Synopsis), the DTSE methodology at Imec, Sadayappan's group at Ohio State University, Rajopadhye's group at Colorado State's University, etc. In the last 10 years, several compiler groups have shown their interest in polyhedral methods, e.g., the Gcc group, IBM, and Reservoir Labs, a company that develops a compiler fully based on the polyhedral model and on the techniques that we (the french community) introduced for loop and array transformations. Polyhedra are also used in test and certification projects (Verimag, Lande, Vertecs). Now that these techniques are well-established and disseminated in and by other groups, we prefer to focus on the development of new techniques and tools, which are described here. Some of these tools can be used through a web interface on the Compsys tool demonstrator web page http://compsys-tools.ens-lyon.fr/ .

Recent activity concerns the development, by Christophe Alias, of HLS compiler parts to be transferred to the XtremLogic start-up (Zettice project) (see Section  7.2 ). An important effort of applied research and software development [12] has been achieved, resulting in the Dcc (DPN C Compiler) tool, outlined in Section  5.5 . Also, optimization developments (scalability, memory leaks, parallelization, etc) were performed on the PoCo compiler framework (see Section  5.6 ) and the Bee tool (see Section  5.7 ).

Also, several successive developments have been made related to termination tools. Our first implementation, RanK (see Section  5.9 ), was extended by other tools such as SToP (see Section  5.12 ) and, more recently Termite, (see Section  5.13 ).