Depth-First Copying Garbage Collection without Extra Stack Space

In this paper, we propose two copying garbage collection methods. These two methods copy data structures in depth-first order, while conventional method copies in breadth-first order. This modification greatly improves memory access locality during both garbage collection and computation after. Restriction on data structure representation is also relaxed because the proposed methods don't require that a data object itself indicates whether it is a pointer. For the depth-first copying, it is necessary to memorize information about non-leaf data structures so that their unprocessed elements are visited afterward. The first proposed method, the link method, links data structures that have unprocessed elements. Another method, the reservation-stack method, pushes each unprocessed element being a pointer to another structure to a stack allocated at the end of the area to which data objects are copied. Therefore, neither of methods requires extra stack space. We evaluated the performance of..