Write barrier removal by static analysis

We present a new analysis for removing unnecessary write barriers in programs that use generational garbage collection. To our knowledge, this is the first static program analysis for this purpose. Our algorithm uses a pointer analysis to locate assignments that always create a reference from a younger object to an older object, then transforms the program to remove the write barriers normally associated with such assignments. We have implemented two transformations that reorder object allocations; these transformations can significantly increase the effectiveness of our write barrier removal algorithm. Our base technique assumes that the collector promotes objects in age order. We have developed an extension that enables the optimistic removal of write barriers, with the collector lazily adding each newly promoted object into a remembered set of objects whenever the compiler may have removed write barriers involving the object at statements that have yet to execute. This mechanism en...

• Type: Journal
• Year: 2002
• Where: SIGPLAN
• Authors: Karen Zee, Martin C. Rinard
• Keywords: Analysis, Generational Garbage Collection, SIGPLAN 2002, System Software, Write Barriers