Study on Instrumentation Algorithm for Just-in-time Compiler Assisted Garbage Collection

Abstract: Just-in-time compiler assisted garbage collection (JIT-assisted GC) combines the advantages of explicit memory management and automatic memory management. Under the framework of JIT-assisted GC, JIT compiler analyses the applications to find dead objects and their dead points, then instruments the explicit "free " instructions in compilation time, accordingly garbage collector could reclaim the spaces owned by those dead objects in time and relieves its load on automatic garbage collection. A new algorithm on instrumenting "free " instructions in JIT-assisted-GC is proposed in this paper. It bases on the domination relations in the control flow and various instrumenting strategies are presented to ensure the validity and flexibility of instrumentation. Moreover, the object fields which refer to dead objects are detected, and instructions for loading those field references are produced and instrumented automatically. Experimental results show that the proposed algorithm for JIT-assisted-GC could reclaim plentiful memory spaces and improve the performance of Java applications efficiently