Initial reorg.

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

crates/runtime/src/imports.rs

@@ -0,0 +1,54 @@
+use crate::instance::InstanceHandle;
+use crate::vmcontext::{VMFunctionImport, VMGlobalImport, VMMemoryImport, VMTableImport};
+use crate::HashSet;
+use cranelift_entity::{BoxedSlice, PrimaryMap};
+use cranelift_wasm::{FuncIndex, GlobalIndex, MemoryIndex, TableIndex};
+
+/// Resolved import pointers.
+#[derive(Clone)]
+pub struct Imports {
+    /// The set of instances that the imports depend on.
+    pub dependencies: HashSet<InstanceHandle>,
+
+    /// Resolved addresses for imported functions.
+    pub functions: BoxedSlice<FuncIndex, VMFunctionImport>,
+
+    /// Resolved addresses for imported tables.
+    pub tables: BoxedSlice<TableIndex, VMTableImport>,
+
+    /// Resolved addresses for imported memories.
+    pub memories: BoxedSlice<MemoryIndex, VMMemoryImport>,
+
+    /// Resolved addresses for imported globals.
+    pub globals: BoxedSlice<GlobalIndex, VMGlobalImport>,
+}
+
+impl Imports {
+    /// Construct a new `Imports` instance.
+    pub fn new(
+        dependencies: HashSet<InstanceHandle>,
+        function_imports: PrimaryMap<FuncIndex, VMFunctionImport>,
+        table_imports: PrimaryMap<TableIndex, VMTableImport>,
+        memory_imports: PrimaryMap<MemoryIndex, VMMemoryImport>,
+        global_imports: PrimaryMap<GlobalIndex, VMGlobalImport>,
+    ) -> Self {
+        Self {
+            dependencies,
+            functions: function_imports.into_boxed_slice(),
+            tables: table_imports.into_boxed_slice(),
+            memories: memory_imports.into_boxed_slice(),
+            globals: global_imports.into_boxed_slice(),
+        }
+    }
+
+    /// Construct a new `Imports` instance with no imports.
+    pub fn none() -> Self {
+        Self {
+            dependencies: HashSet::new(),
+            functions: PrimaryMap::new().into_boxed_slice(),
+            tables: PrimaryMap::new().into_boxed_slice(),
+            memories: PrimaryMap::new().into_boxed_slice(),
+            globals: PrimaryMap::new().into_boxed_slice(),
+        }
+    }
+}