Precise slicing of concurrent programs

Abstract

While there exist efficient algorithms to slice sequential programs precisely, there are only two algorithms for precise slicing of concurrent interprocedural programs with recursive procedures (Krinke 2003;Nanda and Ramesh 2006). We present an empirical evaluation of both algorithms for Java. We demonstrate that both algorithms provide the same precision up to the model of concurrency in use and show that the concurrency model has strong impact on slice precision and computation costs. Furthermore, we extend both algorithms to support dynamic thread creation both in loops and recursion -a feature that the original algorithms could not fully handle. The worst case complexity of the algorithms being exponential, we developed several optimizations and compared these with each other and with algorithms that trade precision for speed. Finally, we show that one algorithm may produce incorrect slices and present a remedy.

Flow-sensitive, context-sensitive, and object-sensitive information flow control based on program dependence graphs

“…The prototype is an Eclipse plugin, which allows interactive definition of security lattices, automatic generation of SDG's, annotation of security levels to SDG nodes via source annotation and automatic security checks [16]. All mechanisms described in previous parts of the paper have been implemented and are working.…”

Slicing Concurrent Programs Based on Program Reachability Graphs

“…If we add parallel flow edges, i.e., edges from cobegin node to the entry node of its each kid thread or from the exit node of each thread to its coend node, the CFGs for all threads in a concurrent program will be connected and the generated graph is called threaded control flow graph (TCFG) [9][10][11][12][13][14].…”

“…Program slicing has been successfully applied in many software engineering activities, such as program understanding, debugging, testing, maintenance, measurement, reengineering [2]. Unfortunately, most approaches and tools for sequential programs cannot be directly applicable to concurrent programs [3][4][5][6][7][8][9][10][11][12][13][14].…”

“…Thus, we try to compute a slice that is as precise as possible. Up to now, researchers have proposed several slicing algorithms by additionally judging whether dependence statement sequences meet the requirement of execution order or not when traversing program dependence graphs [4][5][6][7][8][9][10][11][12][13][14]. Although they may remove considerable redundant statements and improve the precision, these methods have not handled the intransitive dependence problem inherently.…”

“…Although they may remove considerable redundant statements and improve the precision, these methods have not handled the intransitive dependence problem inherently. When there is a redefinition of a shared variable by another thread, some dependence statement sequences may be still intransitive despite of meeting the requirement of execution order [13][14]. If we settle the problem, more precise slice will be obtained.…”