Initial reorg.

This is largely the same as #305, but updated for the current tree.

crates/api/src/trampoline/create_handle.rs

@@ -0,0 +1,62 @@
+//! Support for a calling of an imported function.
+
+use anyhow::Result;
+use cranelift_entity::PrimaryMap;
+use cranelift_wasm::DefinedFuncIndex;
+//use target_lexicon::HOST;
+use wasmtime_environ::Module;
+use wasmtime_runtime::{Imports, InstanceHandle, VMFunctionBody};
+
+use crate::{HashMap, HashSet};
+use alloc::boxed::Box;
+use alloc::rc::Rc;
+use alloc::string::String;
+use alloc::vec::Vec;
+use core::any::Any;
+use core::cell::{RefCell, RefMut};
+
+use crate::runtime::Store;
+
+pub(crate) fn create_handle(
+    module: Module,
+    signature_registry: Option<RefMut<Store>>,
+    finished_functions: PrimaryMap<DefinedFuncIndex, *const VMFunctionBody>,
+    state: Box<dyn Any>,
+) -> Result<InstanceHandle> {
+    let global_exports: Rc<RefCell<HashMap<String, Option<wasmtime_runtime::Export>>>> =
+        Rc::new(RefCell::new(HashMap::new()));
+
+    let imports = Imports::new(
+        HashSet::new(),
+        PrimaryMap::new(),
+        PrimaryMap::new(),
+        PrimaryMap::new(),
+        PrimaryMap::new(),
+    );
+    let data_initializers = Vec::new();
+
+    // Compute indices into the shared signature table.
+    let signatures = signature_registry
+        .and_then(|mut signature_registry| {
+            Some(
+                module
+                    .signatures
+                    .values()
+                    .map(|sig| signature_registry.register_cranelift_signature(sig))
+                    .collect::<PrimaryMap<_, _>>(),
+            )
+        })
+        .unwrap_or_else(|| PrimaryMap::new());
+
+    Ok(InstanceHandle::new(
+        Rc::new(module),
+        global_exports,
+        finished_functions.into_boxed_slice(),
+        imports,
+        &data_initializers,
+        signatures.into_boxed_slice(),
+        None,
+        state,
+    )
+    .expect("instance"))
+}