wasm-spec-interpreter

This project shows how to use ocaml-interop to call into the Wasm spec interpreter. There are several steps to making this work:

• building the OCaml Wasm spec interpreter as a static library
• building a Rust-to-OCaml FFI bridge using ocaml-interop and a custom OCaml wrapper
• linking both things into a Rust crate

Dependencies

This crate only builds in an environment with:

• make (the Wasm spec interpreter uses a Makefile)
• ocamlopt, ocamlbuild (available with, e.g., dnf install ocaml)
• Linux tools (e.g. ar); currently it is easiest to build the static libraries in a single environment but this could be fixed in the future (TODO)
• libgmp, for the OCaml zarith package
• git is used by build.rs to retrieve the repository containing the Wasm spec interpreter; it is safe to completely remove ocaml/spec to get a new copy

Build

cargo build --features build-libinterpret

Use FFI_LIB_DIR=path/to/lib/... to specify a different location for the static library (this is mainly for debugging). If the build-libinterpret feature is not provided, this crate will build successfully but fail at runtime.

Test

cargo test --features build-libinterpret