Add a fallback for argumentsLength without mutable-globals (#1084)

Author: dcodeIO

.github/workflows/ci.yml

@@ -123,3 +123,21 @@ jobs:
         npm run build
         cd ..
         npm test rt-stub
+  test-loader:
+    name: "Test loader on node: node"
+    runs-on: ubuntu-latest
+    needs: check
+    steps:
+    - uses: actions/checkout@v1.0.0
+    - uses: dcodeIO/setup-node-nvm@v1.0.0
+      with:
+        node-version: node
+    - name: Install dependencies
+      run: npm ci --no-audit
+    - name: Clean distribution files
+      run: npm run clean
+    - name: Test the loader
+      run: |
+        cd lib/loader
+        npm run asbuild
+        npm run test

cli/asc.json

@@ -210,15 +210,16 @@
       " exception-handling  Exception handling.",
       " tail-calls          Tail call operations."
     ],
-    "type": "s"
+    "type": "S"
   },
   "disable": {
     "description": [
       "Disables WebAssembly features that are enabled by default.",
       "",
       " mutable-globals     Mutable global imports and exports.",
       ""
-    ]
+    ],
+    "type": "S"
   },
   "transform": {
     "description": "Specifies the path to a custom transform to 'require'.",

lib/loader/index.js

@@ -276,16 +276,6 @@ function postInstantiate(baseModule, instance) {
   return demangle(rawExports, baseModule);
 }
 
-/** Wraps a WebAssembly function while also taking care of variable arguments. */
-function wrapFunction(fn, argumentsLength) {
-  var wrap = (...args) => {
-    if (argumentsLength) argumentsLength.value = args.length;
-    return fn(...args);
-  }
-  wrap.original = fn;
-  return wrap;
-}
-
 function isResponse(o) {
   return typeof Response !== "undefined" && o instanceof Response;
 }
@@ -342,18 +332,17 @@ exports.instantiateStreaming = instantiateStreaming;
 /** Demangles an AssemblyScript module's exports to a friendly object structure. */
 function demangle(exports, baseModule) {
   var module = baseModule ? Object.create(baseModule) : {};
-  var argumentsLength = exports["__argumentsLength"];
-  function hasOwnProperty(elem, prop) {
-    return Object.prototype.hasOwnProperty.call(elem, prop);
-  }
+  var setArgumentsLength = exports["__argumentsLength"]
+    ? function(length) { exports["__argumentsLength"].value = length; }
+    : exports["__setArgumentsLength"] || exports["__setargc"] || function() {};
   for (let internalName in exports) {
-    if (!hasOwnProperty(exports, internalName)) continue;
-    let elem = exports[internalName];
+    if (!Object.prototype.hasOwnProperty.call(exports, internalName)) continue;
+    const elem = exports[internalName];
     let parts = internalName.split(".");
     let curr = module;
     while (parts.length > 1) {
       let part = parts.shift();
-      if (!hasOwnProperty(curr, part)) curr[part] = {};
+      if (!Object.prototype.hasOwnProperty.call(curr, part)) curr[part] = {};
       curr = curr[part];
     }
     let name = parts[0];
@@ -381,7 +370,7 @@ function demangle(exports, baseModule) {
       name = name.substring(hash + 1);
       curr = curr[className].prototype;
       if (/^(get|set):/.test(name)) {
-        if (!hasOwnProperty(curr, name = name.substring(4))) {
+        if (!Object.prototype.hasOwnProperty.call(curr, name = name.substring(4))) {
           let getter = exports[internalName.replace("set:", "get:")];
           let setter = exports[internalName.replace("get:", "set:")];
           Object.defineProperty(curr, name, {
@@ -392,33 +381,36 @@ function demangle(exports, baseModule) {
         }
       } else {
         if (name === 'constructor') {
-          curr[name] = wrapFunction(elem, argumentsLength);
-        } else { // for methods
-          Object.defineProperty(curr, name, {
-            value: function (...args) {
-              if (argumentsLength) argumentsLength.value = args.length;
-              return elem(this[THIS], ...args);
-            }
-          });
+          (curr[name] = (...args) => {
+            setArgumentsLength(args.length);
+            return elem(...args);
+          }).original = elem;
+        } else { // instance method
+          (curr[name] = function(...args) { // !
+            setArgumentsLength(args.length);
+            return elem(this[THIS], ...args);
+          }).original = elem;
         }
       }
     } else {
       if (/^(get|set):/.test(name)) {
-        if (!hasOwnProperty(curr, name = name.substring(4))) {
+        if (!Object.prototype.hasOwnProperty.call(curr, name = name.substring(4))) {
           Object.defineProperty(curr, name, {
             get: exports[internalName.replace("set:", "get:")],
             set: exports[internalName.replace("get:", "set:")],
             enumerable: true
           });
         }
-      } else if (typeof elem === "function") {
-        curr[name] = wrapFunction(elem, argumentsLength);
+      } else if (typeof elem === "function" && elem !== setArgumentsLength) {
+        (curr[name] = (...args) => {
+          setArgumentsLength(args.length);
+          return elem(...args);
+        }).original = elem;
       } else {
         curr[name] = elem;
       }
     }
   }
-
   return module;
 }
 

lib/loader/package.json

@@ -24,7 +24,9 @@
   "main": "index.js",
   "types": "index.d.ts",
   "scripts": {
-    "test:build": "asc tests/assembly/index.ts -b tests/build/untouched.wasm",
+    "asbuild": "npm run asbuild:default && npm run asbuild:legacy",
+    "asbuild:default": "node ../../bin/asc tests/assembly/index.ts -b tests/build/default.wasm",
+    "asbuild:legacy": "node ../../bin/asc tests/assembly/index.ts --disable mutable-globals -b tests/build/legacy.wasm",
     "test": "node tests"
   },
   "files": [