PackageToJS: Extend instantiation hooks to allow instance instrumentation

Plugins/PackageToJS/Templates/instantiate.d.ts

@@ -93,12 +93,30 @@ export type InstantiateOptions = {
     /**
      * Add imports to the WebAssembly import object
      * @param imports - The imports to add
+     * @param context - The context object
      */
     addToCoreImports?: (
         imports: WebAssembly.Imports,
-        getInstance: () => WebAssembly.Instance | null,
-        getExports: () => Exports | null,
+        context: {
+            getInstance: () => WebAssembly.Instance | null,
+            getExports: () => Exports | null,
+            _swift: SwiftRuntime,
+        }
     ) => void
+
+    /**
+     * Instrument the WebAssembly instance
+     *
+     * @param instance - The instance of the WebAssembly module
+     * @param context - The context object
+     * @returns The instrumented instance
+     */
+    instrumentInstance?: (
+        instance: WebAssembly.Instance,
+        context: {
+            _swift: SwiftRuntime
+        }
+    ) => WebAssembly.Instance
 }
 
 /**

Plugins/PackageToJS/Templates/instantiate.js

@@ -94,7 +94,11 @@ async function _instantiate(
 /* #endif */
     };
     instantiator.addImports(importObject);
-    options.addToCoreImports?.(importObject, () => instance, () => exports);
+    options.addToCoreImports?.(importObject, {
+        getInstance: () => instance,
+        getExports: () => exports,
+        _swift: swift,
+    });
 
     let module;
     let instance;
@@ -117,6 +121,7 @@ async function _instantiate(
         module = await _WebAssembly.compile(moduleSource);
         instance = await _WebAssembly.instantiate(module, importObject);
     }
+    instance = options.instrumentInstance?.(instance, { _swift: swift }) ?? instance;
 
     swift.setInstance(instance);
     instantiator.setInstance(instance);

Plugins/PackageToJS/Templates/test.js

@@ -171,8 +171,8 @@ export async function testBrowserInPage(options, processInfo) {
         // Instantiate the WebAssembly file
         return await instantiate({
             ...options,
-            addToCoreImports: (imports) => {
-                options.addToCoreImports?.(imports);
+            addToCoreImports: (imports, context) => {
+                options.addToCoreImports?.(imports, context);
                 imports["wasi_snapshot_preview1"]["proc_exit"] = (code) => {
                     exitTest(code);
                     throw new ExitError(code);

Tests/prelude.mjs

@@ -4,8 +4,9 @@ export function setupOptions(options, context) {
     setupTestGlobals(globalThis);
     return {
         ...options,
-        addToCoreImports(importObject, getInstance, getExports) {
-            options.addToCoreImports?.(importObject);
+        addToCoreImports(importObject, importsContext) {
+            const { getInstance, getExports } = importsContext;
+            options.addToCoreImports?.(importObject, importsContext);
             importObject["JavaScriptEventLoopTestSupportTests"] = {
                 "isMainThread": () => context.isMainThread,
             }