Dynamic Memory Allocation Techniques for High-level Synthesis

The omission of support for several software-defined constructs within High-Level Synthesis (HLS) have hindered it’s broad adoption. Dynamic memory allocation is one feature that is not within the traditional supported subset. This works expands the synthesizable subset of the C languages for HLS tools, by including dynamic memory allocation algorithms (i.e. malloc and free). We define a variety of high-level synthesis approaches to support malloc and free. We first provide a library of HLS-friendly allocation algorithms, libmem, which is studied for performance and area impacts. We also define a framework to improve the performance and area of dynamic memory allocation mechanisms in HLS applications. Our framework employs a variety of dynamic and static program analyses to identify the required size of the heap memory space, parallelize dynamic memory allocators and save precious on-chip BRAM. We evaluate our work with a variety of benchmarks, and demonstrate the usefulness of including dynamic memory allocation within HLS.M.A.S