GeneratorFunction() makes generator instances

src/generator.js

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 47 matching lines @@
 
 function GeneratorObjectThrow(exn) {
   if (!IS_GENERATOR(this)) {
     throw MakeTypeError('incompatible_method_receiver',
                         ['[Generator].prototype.throw', this]);
   }
 
   return %_GeneratorThrow(this, exn);
 }
 
+function GeneratorFunctionPrototypeConstructor(x) {
+  if (%_IsConstructCall()) {
+    throw MakeTypeError('not_constructor', ['GeneratorFunctionPrototype']);
+  }
+}
+
+function GeneratorFunctionConstructor(arg1) {  // length == 1
+  var source = NewFunctionString(arguments, 'function*');
+  var global_receiver = %GlobalReceiver(global);
+  // Compile the string in the constructor and not a helper so that errors
+  // appear to come from here.
+  var f = %_CallFunction(global_receiver, %CompileString(source, true));
+  %FunctionMarkNameShouldPrintAsAnonymous(f);
+  return f;
+}
+
+
 function SetUpGenerators() {
   %CheckIsBootstrapping();
   var GeneratorObjectPrototype = GeneratorFunctionPrototype.prototype;
   InstallFunctions(GeneratorObjectPrototype,
                    DONT_ENUM | DONT_DELETE | READ_ONLY,
                    ["next", GeneratorObjectNext,
                     "send", GeneratorObjectSend,
                     "throw", GeneratorObjectThrow]);
   %SetProperty(GeneratorObjectPrototype, "constructor",
                GeneratorFunctionPrototype, DONT_ENUM | DONT_DELETE | READ_ONLY);
   %SetPrototype(GeneratorFunctionPrototype, $Function.prototype);
+  %SetCode(GeneratorFunctionPrototype, GeneratorFunctionPrototypeConstructor);
   %SetProperty(GeneratorFunctionPrototype, "constructor",
                GeneratorFunction, DONT_ENUM | DONT_DELETE | READ_ONLY);
   %SetPrototype(GeneratorFunction, $Function);
+  %SetCode(GeneratorFunction, GeneratorFunctionConstructor);
 }
 
 SetUpGenerators();