Extending the OpenSHMEM analyzer to perform synchronization and multi-valued analysis

OpenSHMEM Analyzer (OSA) is a compiler-based tool that provides static analysis forOpenSHMEMprograms. It was developed with the intention of providing feedback to the users about semantics errors due to incorrect use of the OpenSHMEM API in their programs, thus making development of OpenSHMEMapplications an easier task for beginners as well as experienced programmers. In this paper we discuss the improvements to theOSA tool to perform parallel analysis to detect collective synchronization structure of a program. Synchronization is a critical aspect of all programming models and in OpenSHMEMit is the responsibility of the programmer to introduce synchronization calls to ensure the completion of communication among processing elements (PEs) to prevent use of old/incorrect data, avoid deadlocks and ensure data race free execution keeping in mind the semantics of OpenSHMEM library specification. Our analysis yields three tangible outputs: a detailed control flow graph (CFG) making all the OpenSHMEM calls used, a system dependence graph and a barrier tree. The barrier tree represents the synchronization structure of the programpresented in a simplisticmanner that enables visualization of the program's synchronization keeping in mind the concurrent nature of SPMD applications that use OpenSHMEM library calls. This provides a graphical representation of the synchronization calls in the order in which they appear at execution time and how the different PEs in OpenSHMEMmay encounter them based upon the different execution paths available in the program. Our results include the summarization of the analysis conducted within themiddle-endof a compiler and the improvementswe have done to the existing analysis to make it aware of the parallelism in the OpenSHMEM program.