LLVM Might Get An AAP Back-End (Altruistic Processor)

There's an active proposal to incorporate a back-end into LLVM for AAP, a processor ISA for deeply-embedded Harvard architectures.

AAP is designed for FPGA usage and there is an open-source soft-core with commercial deployments also being available. AAP is short for the Altruistic Processor and is described in technical detail here. AAP is said to be an original design but inspired by the OpenRISC / RISC-V projects.

AAP stakeholders have already designed a complete LLVM/Clang toolchain and GDB/Binutils support, etc, around their simulator implementations. Developers are also working on AAP architecture support for the GCC compiler.

The AAP backend for LLVM is at a point where the developers are hoping to mainline the code. Their request for comments can be found here.

While the open-source Altruistic Processor sounds interesting from a technical perspective for possible embedded systems, so far there is some disagreement by LLVM developers whether to accept this backend. There is concern whether there are enough users interested in AAP, whether there are sufficient developers to maintain this backend if it's to be mainlined, and similar questions about whether it's worthwhile to upstream having this code in their tree. We'll see in the days/weeks ahead what happens and if there's anything else interesting to report on AAP. For now the code is available via GitHub for those wanting to learn more about Altruistic this weekend.