Runtime prevention of concurrency related type-state violations in multithreaded applications

Abstract

We propose a new method for runtime prevention of type state violations in multithreaded applications due to erroneous thread interleavings. The new method employs a combination of static and dynamic program analysis techniques to control the execution order of the method calls to suppress illegal call sequences. The legal behavior of a shared object is specified by a type-state automaton, which serves as the guidance for our method to delay certain method calls at run time. Our main contribution is a new theoretical framework for ensuring that the runtime prevention strategy is always safe, i.e., they do not introduce new erroneous interleavings. Furthermore, whenever the static program analysis is precise enough, our method guarantees to steer the program to a failurefree interleaving as long as such interleaving exists. We have implemented the new method in a tool based on the LLVM compiler framework. Our experiments on a set of multithreaded C/C++ applications show that the method is both efficient and effective in suppressing concurrency related type-state violations.