6b137c2a3d
After compilation there's actually no need to hold onto the native signature for a wasm function type, so this commit moves out the `ir::Signature` value from a `Module` into a separate field that's deallocated when compilation is finished. This simplifies the `SignatureRegistry` because it only needs to track wasm functino types and it also means less work is done for `Func::wrap`.
This is the wasmtime-environ crate, which contains the implementations
of the ModuleEnvironment and FuncEnvironment traits from
cranelift-wasm. They effectively
implement an ABI for basic wasm compilation that defines how linear memories
are allocated, how indirect calls work, and other details. They can be used
for JITing, native object files, or other purposes.