b58afbf849
This commit refactors module instantiation in the runtime to allow for different instance allocation strategy implementations. It adds an `InstanceAllocator` trait with the current implementation put behind the `OnDemandInstanceAllocator` struct. The Wasmtime API has been updated to allow a `Config` to have an instance allocation strategy set which will determine how instances get allocated. This change is in preparation for an alternative *pooling* instance allocator that can reserve all needed host process address space in advance. This commit also makes changes to the `wasmtime_environ` crate to represent compiled modules in a way that reduces copying at instantiation time.
This is the wasmtime-jit crate, which contains JIT-based execution
for wasm, using the wasm ABI defined by wasmtime-environ and the
runtime support provided by wasmtime-runtime.
Most users will want to use the main wasmtime crate instead of using this
crate directly.