* Port v8 fuzzer to the new framework This commit aims to improve the support for the new "meta" differential fuzzer added in #4515 by ensuring that all existing differential fuzzing is migrated to this new fuzzer. This PR includes features such as: * The V8 differential execution is migrated to the new framework. * `Config::set_differential_config` no longer force-disables wasm features, instead allowing them to be enabled as per the fuzz input. * `DiffInstance::{hash, hash}` was replaced with `DiffInstance::get_{memory,global}` to allow more fine-grained assertions. * Support for `FuncRef` and `ExternRef` have been added to `DiffValue` and `DiffValueType`. For now though generating an arbitrary `ExternRef` and `FuncRef` simply generates a null value. * Arbitrary `DiffValue::{F32,F64}` values are guaranteed to use canonical NaN representations to fix an issue with v8 where with the v8 engine we can't communicate non-canonical NaN values through JS. * `DiffEngine::evaluate` allows "successful failure" for cases where engines can't support that particular invocation, for example v8 can't support `v128` arguments or return values. * Smoke tests were added for each engine to ensure that a simple wasm module works at PR-time. * Statistics printed from the main fuzzer now include percentage-rates for chosen engines as well as percentage rates for styles-of-module. There's also a few small refactorings here and there but mostly just things I saw along the way. * Update the fuzzing README
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-interopand 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 aMakefile)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 OCamlzarithpackagegitis used bybuild.rsto retrieve the repository containing the Wasm spec interpreter; it is safe to completely removeocaml/specto 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