Languages Must Expose Memory Heterogeneity

The last decade has seen an explosion in new and innovative memory technologies. While certain technologies, like transactional memory, have seen adoption at the language level, others, such as sandboxed memory, scratchpad memory, and persistent memory, have not received any systematic programming language support. This is true even though the underlying compiler-level mechanisms for these mechanisms are similar. In this paper, we argue that programming languages must be enhanced to expose heterogeneous memory technologies to programmers, so that they can enjoy the benefits of those technologies and be able to reason about programs that use the advanced features of novel memory technologies. We sketch a language design that allows programmers to specify memory requirements and behaviors, for both data and code. We further describe how a compiler can support such a language and suggest hardware improvements that can improve efficiencies of heterogeneous memories.