Getting Rid of Store-Buffers in TSO Analysis

Abstract

Abstract. We propose an approach for reducing the TSO reachability analysis of concurrent programs to their SC reachability analysis, under some conditions on the explored behaviors. First, we propose a linear code-to-code translation that takes as input a concurrent program P and produces a concurrent program P such that, running P under SC yields the same set of reachable (shared) states as running P under TSO with at most k context-switches for each thread, for a fixed k. Basically, we show that it is possible to use only O(k) additional copies of the shared variables of P as local variables to simulate the store buffers, even if they are unbounded. Furthermore, we show that our translation can be extended so that an unbounded number of context-switches is possible, under the condition that each write operation sent to the store buffer stays there for at most k contextswitches of the thread. Experimental results show that bugs due to TSO can be detected with small bounds, using off-the-shelf SC analysis tools.

Counter-Example Guided Fence Insertion under TSO

“…Existing approaches avoid solving the general problem by considering under-approximations, over-approximations, restricted classes of programs, forbidding sequential inconsistent behavior, or by proposing exact algorithms for which termination is not guaranteed. Under-approximations of the program behavior can be achieved through testing [9], bounded model checking [7,6], or by restricting the behavior of the program, e.g., through bounding the sizes of the buffers [18] or the number of switches [5]. Such techniques are useful in practice for finding errors.…”

Context-Bounded Analysis for POWER

“…These are widespread medium-sized benchmarks that are used by many tools for analyzing concurrent programs running under weak memory models (e.g. [24,12,15,10,40,2,37,13,3,8,22,7,4,14]). We divide our results in two sets.…”

“…We investigate the issue of defining approximate analysis. Our approach consists in introducing a parametric under-approximation schema in the spirit of context-bounding [33,31,27,25,12]. Context-bounding has been proposed in [33] as a suitable approach for efficient bug detection in multithreaded programs.…”

“…In the context of weak memory models, context-bounded analysis has been extended in [12] to the case of programs running on TSO. The work we present here aims at extending this approach to the case of POWER.…”

“…There has been a lot of work on automatic program verification under weak memory models, based on precise, under-approximate, and abstract analyses, e.g., [29,23,24,12,36,37,18,5,8,15,16,13,14,39,2,40,20,10,38,26,19]. While most of these works concern TSO, only a few of them address the safety verification problem under POWER (e.g., [6,10,36,9,11]).…”