[embind] Remove newFunc helper. NFC (#23937)

The newFunc approach is kind old, from 2013, using new Function can
improve the performance drawback from prototype re-assigning.

Author: mikelxk

src/lib/libembind.js

@@ -18,7 +18,7 @@
 /*global floatReadValueFromPointer, integerReadValueFromPointer, enumReadValueFromPointer, replacePublicSymbol, craftInvokerFunction, tupleRegistrations*/
 /*global finalizationRegistry, attachFinalizer, detachFinalizer, releaseClassHandle, runDestructor*/
 /*global ClassHandle, makeClassHandle, structRegistrations, whenDependentTypesAreResolved, BindingError, deletionQueue, delayFunction:true, upcastPointer*/
-/*global exposePublicSymbol, heap32VectorToArray, newFunc, char_0, char_9*/
+/*global exposePublicSymbol, heap32VectorToArray, char_0, char_9*/
 /*global getInheritedInstanceCount, getLiveInheritedInstances, setDelayFunction, InternalError, runDestructors*/
 /*global requireRegisteredType, unregisterInheritedInstance, registerInheritedInstance, PureVirtualError, throwUnboundTypeError*/
 /*global assert, validateThis, downcastPointer, registeredPointers, RegisteredClass, getInheritedInstance */
@@ -705,42 +705,14 @@ var LibraryEmbind = {
     }
   },
 
-#if DYNAMIC_EXECUTION
-  $newFunc__deps: ['$createNamedFunction'],
-  $newFunc: function(constructor, argumentList) {
-    if (!(constructor instanceof Function)) {
-      throw new TypeError(`new_ called with constructor type ${typeof(constructor)} which is not a function`);
-    }
-    /*
-     * Previously, the following line was just:
-     *   function dummy() {};
-     * Unfortunately, Chrome was preserving 'dummy' as the object's name, even
-     * though at creation, the 'dummy' has the correct constructor name.  Thus,
-     * objects created with IMVU.new would show up in the debugger as 'dummy',
-     * which isn't very helpful.  Using IMVU.createNamedFunction addresses the
-     * issue.  Doubly-unfortunately, there's no way to write a test for this
-     * behavior.  -NRD 2013.02.22
-     */
-    var dummy = createNamedFunction(constructor.name || 'unknownFunctionName', function(){});
-    dummy.prototype = constructor.prototype;
-    var obj = new dummy;
-
-    var r = constructor.apply(obj, argumentList);
-    return (r instanceof Object) ? r : obj;
-  },
-#endif
-
   // The path to interop from JS code to C++ code:
   // (hand-written JS code) -> (autogenerated JS invoker) -> (template-generated C++ invoker) -> (target C++ function)
   // craftInvokerFunction generates the JS invoker function for each function exposed to JS through embind.
   $craftInvokerFunction__deps: [
     '$createNamedFunction', '$runDestructors', '$throwBindingError', '$usesDestructorStack',
-#if DYNAMIC_EXECUTION
-    '$newFunc',
 #if !EMBIND_AOT
     '$createJsInvoker',
 #endif
-#endif
 #if EMBIND_AOT
     '$InvokerFunctions',
     '$createJsInvokerSignature',
@@ -878,9 +850,11 @@ var LibraryEmbind = {
     var signature = createJsInvokerSignature(argTypes, isClassMethodFunc, returns, isAsync);
     var invokerFn = InvokerFunctions[signature](...closureArgs);
 #else
+
     let [args, invokerFnBody] = createJsInvoker(argTypes, isClassMethodFunc, returns, isAsync);
     args.push(invokerFnBody);
-    var invokerFn = newFunc(Function, args)(...closureArgs);
+    var invokerFn = new Function(...args)(...closureArgs);
+
 #endif
 #endif
     return createNamedFunction(humanName, invokerFn);

src/lib/libembind_gen.js

@@ -857,7 +857,6 @@ var LibraryEmbind = {
 
   // Stub functions used by eval, but not needed for TS generation:
   $makeLegalFunctionName: () => { throw new Error('stub function should not be called'); },
-  $newFunc: () => { throw new Error('stub function should not be called'); },
   $runDestructors: () => { throw new Error('stub function should not be called'); },
   $createNamedFunction: () => { throw new Error('stub function should not be called'); },
 };

src/lib/libemval.js

@@ -5,7 +5,6 @@
 
 /*global Module:true, Runtime*/
 /*global HEAP32*/
-/*global newFunc*/
 /*global createNamedFunction*/
 /*global readLatin1String, stringToUTF8*/
 /*global requireRegisteredType, throwBindingError, runDestructors*/
@@ -332,9 +331,6 @@ var LibraryEmVal = {
     '$emval_addMethodCaller', '$emval_lookupTypes',
     '$createNamedFunction',
     '$reflectConstruct', '$emval_returnValue',
-#if DYNAMIC_EXECUTION
-    '$newFunc',
-#endif
   ],
   _emval_get_method_caller: (argCount, argTypes, kind) => {
     var types = emval_lookupTypes(argCount, argTypes);
@@ -384,7 +380,7 @@ var LibraryEmVal = {
       "};\n";
 
     params.push(functionBody);
-    var invokerFunction = newFunc(Function, params)(...args);
+    var invokerFunction = new Function(...params)(...args);
 #endif
     var functionName = `methodCaller<(${types.map(t => t.name).join(', ')}) => ${retType.name}>`;
     return emval_addMethodCaller(createNamedFunction(functionName, invokerFunction));

test/code_size/embind_hello_wasm.json

@@ -1,10 +1,10 @@
 {
   "a.html": 552,
   "a.html.gz": 380,
-  "a.js": 9750,
-  "a.js.gz": 4262,
+  "a.js": 9482,
+  "a.js.gz": 4167,
   "a.wasm": 7348,
   "a.wasm.gz": 3378,
-  "total": 17650,
-  "total_gz": 8020
+  "total": 17382,
+  "total_gz": 7925
 }