Precise and scalable context-sensitive pointer analysis via value flow graph

In this paper, we propose a novel method for context-sensitive pointer analysis using the value flow graph (VFG) formulation. We achieve context-sensitivity by simultaneously applying function cloning and computing context-free language reachability (CFL-reachability) in a novel way. In contrast to existing clone-based and CFL-based approaches, flow-sensitivity is easily integrated in our approach by using a flow-sensitive VFG where each value flow edge is computed in a flow-sensitive manner. We apply context-sensitivity to both local variables and heap objects and propose a new approximation for heap cloning. We prove that our approach can achieve context-sensitivity without loss of precision, i.e., it is as precise as inlining all function calls. We develop an efficient algorithm and implement a context-, flow-, and field-sensitive pointer analysis with heap cloning support in LLVM. We evaluate the efficiency and precision of our implementation using standard SPEC CPU2006 benchmarks. Our experimental results show that the analysis is much faster than existing approaches, it scales well to large real-world applications, and it enables more effective compiler optimizations.