Section: New Results

Dataflow Analysis of Polyhedral X10 Programs

Participants : Paul Feautrier, Sanjay Rajopadhye [Colorado State Universty] , Vijay Saraswat [IBM Research] , Tomofumi Yuki [Colorado State University] .

X10 is a recent parallel language, developed by IBM Research, whose aim is to increase programmers productivity. It is a descendant of Java and it includes several new parallel constructs, such as async and finish , which generalize fork and join , clocks, which generalize barriers, and at , which enables the remote execution of program fragments. X10 programs are guaranteed to be deadlock-free, but may exhibit non-deterministic behaviors or races.

We have devised a verifier for the async /finish fragment of X10 and polyhedral programs. The approach consists in computing the source of each array access. In the presence of parallel constructs, the sequencing predicate is no longer a total order and a read may have several sources, which indicates a race. A proof-of-concept tool has been implemented. This work will be presented at the next Principles and Practice of Parallel Programming conference (PPoPP'13 in Shenzen, China) [13] .