Automatic Promotion of Helper Functions to TCG Using LLVM

Explore a build-time tool called helper2tcg that translates C helper functions directly to optimized Tiny Code Generators for QEMU. Learn how this IR-to-IR translator maps LLVM IR produced by clang to QEMU's IR, leveraging existing optimization passes like autovectorization to produce efficient output code with minimal manual effort. Discover the tool's application to the Hexagon frontend, where it emits efficient Tiny Code for 1400 out of 2000 instructions, resulting in impressive performance improvements, particularly for vector instructions with up to 40x speedup. Witness an interactive demo showcasing C to TCG mappings in this 28-minute KVM Forum talk, which addresses the challenges of describing instruction semantics using Tiny Code for CISC architectures in QEMU frontends.