[emval] Simplify dynamic invoker creation. NFC

src/lib/libembind.js

@@ -668,7 +668,7 @@ var LibraryEmbind = {
     // TODO: Remove this completely once all function invokers are being dynamically generated.
     var needsDestructorStack = usesDestructorStack(argTypes);
 
-    var returns = (argTypes[0].name !== 'void');
+    var returns = !argTypes[0].isVoid;
 
     var expectedArgCount = argCount - 2;
 #if ASSERTIONS
@@ -766,8 +766,8 @@ var LibraryEmbind = {
     var invokerFn = InvokerFunctions[signature](...closureArgs);
 #else
 
-    let [args, invokerFnBody] = createJsInvoker(argTypes, isClassMethodFunc, returns, isAsync);
-    var invokerFn = new Function(...args, invokerFnBody)(...closureArgs);
+    let invokerFactory = createJsInvoker(argTypes, isClassMethodFunc, returns, isAsync);
+    var invokerFn = invokerFactory(...closureArgs);
 #endif
 #endif
     return createNamedFunction(humanName, invokerFn);

src/lib/libembind_gen.js

@@ -134,13 +134,13 @@ var LibraryEmbind = {
       for (const argType of this.argumentTypes) {
         argTypes.push(this.convertToEmbindType(argType.type));
       }
-      const signature = createJsInvokerSignature(argTypes, !!this.thisType, this.returnType.name !== 'void', this.isAsync)
+      const signature = createJsInvokerSignature(argTypes, !!this.thisType, !this.returnType.isVoid, this.isAsync)
       if (emittedFunctions.has(signature)) {
         return;
       }
       emittedFunctions.add(signature);
-      let [args, body] = createJsInvoker(argTypes, !!this.thisType, this.returnType.name !== 'void', this.isAsync);
-      out.push(`'${signature}': function(${args.join(',')}) {\n${body}},`);
+      let invokerFactory = createJsInvoker(argTypes, !!this.thisType, !this.returnType.isVoid, this.isAsync);
+      out.push(`'${signature}': ${invokerFactory},`);
     }
   },
   $PointerDefinition: class {

src/lib/libembind_shared.js

@@ -293,7 +293,7 @@ var LibraryEmbindShared = {
     args1.push('checkArgCount', 'minArgs', 'maxArgs');
     invokerFnBody = `if (arguments.length !== ${args1.length}){ throw new Error(humanName + "Expected ${args1.length} closure arguments " + arguments.length + " given."); }\n${invokerFnBody}`;
 #endif
-    return [args1, invokerFnBody];
+    return new Function(args1, invokerFnBody);
   }
 };
 

src/lib/libemval.js

@@ -297,52 +297,41 @@ var LibraryEmVal = {
       return emval_returnValue(toReturnWire, destructorsRef, rv);
     };
 #else
-    var functionBody =
-      `return function (handle, methodName, destructorsRef, args) {\n`;
-
-    var offset = 0;
-    var argsList = []; // 'arg0, arg1, arg2, ... , argN'
-    var params = ['toValue'];
-    var args = [Emval.toValue];
-    for (var i = 0; i < argCount; ++i) {
-      argsList.push(`arg${i}`);
-      params.push(`argFromPtr${i}`);
-      args.push(argFromPtr[i]);
-      functionBody +=
-        `  var arg${i} = argFromPtr${i}(args${offset ? '+' + offset : ''});\n`;
-      offset += GenericWireTypeSize;
-    }
-    var invoker;
+    var captures = {'toValue': Emval.toValue};
+    var args = argFromPtr.map((argFromPtr, i) => {
+      var captureName = `argFromPtr${i}`;
+      captures[captureName] = argFromPtr;
+      return `${captureName}(args${i ? '+' + i * GenericWireTypeSize : ''})`;
+    });
+    var functionBody;
     switch (kind){
       case {{{ cDefs['internal::EM_INVOKER_KIND::FUNCTION'] }}}:
-        invoker = 'toValue(handle)';
+        functionBody = 'toValue(handle)';
         break;
       case {{{ cDefs['internal::EM_INVOKER_KIND::CONSTRUCTOR'] }}}:
-        invoker = 'new (toValue(handle))';
+        functionBody = 'new (toValue(handle))';
         break;
       case {{{ cDefs['internal::EM_INVOKER_KIND::CAST'] }}}:
-        invoker = '';
+        functionBody = '';
         break;
       case {{{ cDefs['internal::EM_INVOKER_KIND::METHOD'] }}}:
-        params.push('getStringOrSymbol');
-        args.push(getStringOrSymbol);
-        invoker = 'toValue(handle)[getStringOrSymbol(methodName)]';
+        captures['getStringOrSymbol'] = getStringOrSymbol;
+        functionBody = 'toValue(handle)[getStringOrSymbol(methodName)]';
         break;
     }
-    functionBody +=
-      `  var rv = ${invoker}(${argsList.join(', ')});\n`;
+    functionBody += `(${args})`;
     if (!retType.isVoid) {
-      params.push('toReturnWire', 'emval_returnValue');
-      args.push(toReturnWire, emval_returnValue);
-      functionBody +=
-        '  return emval_returnValue(toReturnWire, destructorsRef, rv);\n';
+      captures['toReturnWire'] = toReturnWire;
+      captures['emval_returnValue'] = emval_returnValue;
+      functionBody = `return emval_returnValue(toReturnWire, destructorsRef, ${functionBody})`;
     }
-    functionBody +=
-      "};\n";
+    functionBody = `return function (handle, methodName, destructorsRef, args) {
+${functionBody}
+}`;
 
-    var invokerFunction = new Function(...params, functionBody)(...args);
+    var invokerFunction = new Function(Object.keys(captures), functionBody)(...Object.values(captures));
 #endif
-    var functionName = `methodCaller<(${argTypes.map(t => t.name).join(', ')}) => ${retType.name}>`;
+    var functionName = `methodCaller<(${argTypes.map(t => t.name)}) => ${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": 7266,
-  "a.js.gz": 3321,
+  "a.js": 7255,
+  "a.js.gz": 3318,
   "a.wasm": 7300,
   "a.wasm.gz": 3348,
-  "total": 15118,
-  "total_gz": 7049
+  "total": 15107,
+  "total_gz": 7046
 }

test/code_size/embind_val_wasm.json

@@ -1,10 +1,10 @@
 {
   "a.html": 552,
   "a.html.gz": 380,
-  "a.js": 5367,
-  "a.js.gz": 2540,
+  "a.js": 5356,
+  "a.js.gz": 2531,
   "a.wasm": 9101,
   "a.wasm.gz": 4698,
-  "total": 15020,
-  "total_gz": 7618
+  "total": 15009,
+  "total_gz": 7609
 }