diff --git a/Makefile b/Makefile
index f3dc5a995..0341cf99c 100644
--- a/Makefile
+++ b/Makefile
@@ -2,6 +2,7 @@ RUNTIME_SRC = \
   src/runtime/runtime.js \
   src/runtime/spread.js \
   src/runtime/classes.js \
+  src/runtime/generators.js \
   src/runtime/url.js \
   src/runtime/ModuleStore.js
 SRC = \
diff --git a/bin/traceur.js b/bin/traceur.js
index 4b1bc7ca0..b13c76c06 100644
--- a/bin/traceur.js
+++ b/bin/traceur.js
@@ -267,6 +267,149 @@
       throw $TypeError(x + ' is not an Object');
     return x;
   }
+  function setupGlobals(global) {
+    global.Symbol = Symbol;
+    polyfillObject(global.Object);
+  }
+  setupGlobals(global);
+  global.$traceurRuntime = {
+    assertObject: assertObject,
+    exportStar: exportStar,
+    getOwnHashObject: getOwnHashObject,
+    setProperty: setProperty,
+    setupGlobals: setupGlobals,
+    toObject: toObject,
+    toProperty: toProperty,
+    type: types,
+    typeof: typeOf,
+    createPrivateName: createPrivateName,
+    defineProperties: $defineProperties,
+    defineProperty: $defineProperty,
+    getOwnPropertyDescriptor: $getOwnPropertyDescriptor,
+    getOwnPropertyNames: $getOwnPropertyNames
+  };
+})(typeof global !== 'undefined' ? global : this);
+(function() {
+  'use strict';
+  var toObject = $traceurRuntime.toObject;
+  function spread() {
+    var rv = [],
+        k = 0;
+    for (var i = 0; i < arguments.length; i++) {
+      var valueToSpread = toObject(arguments[i]);
+      for (var j = 0; j < valueToSpread.length; j++) {
+        rv[k++] = valueToSpread[j];
+      }
+    }
+    return rv;
+  }
+  $traceurRuntime.spread = spread;
+})();
+(function() {
+  'use strict';
+  var $Object = Object;
+  var $TypeError = TypeError;
+  var $create = $Object.create;
+  var $defineProperties = $traceurRuntime.defineProperties;
+  var $defineProperty = $traceurRuntime.defineProperty;
+  var $getOwnPropertyDescriptor = $traceurRuntime.getOwnPropertyDescriptor;
+  var $getOwnPropertyNames = $traceurRuntime.getOwnPropertyNames;
+  var $getPrototypeOf = Object.getPrototypeOf;
+  function superDescriptor(homeObject, name) {
+    var proto = $getPrototypeOf(homeObject);
+    do {
+      var result = $getOwnPropertyDescriptor(proto, name);
+      if (result)
+        return result;
+      proto = $getPrototypeOf(proto);
+    } while (proto);
+    return undefined;
+  }
+  function superCall(self, homeObject, name, args) {
+    return superGet(self, homeObject, name).apply(self, args);
+  }
+  function superGet(self, homeObject, name) {
+    var descriptor = superDescriptor(homeObject, name);
+    if (descriptor) {
+      if (!descriptor.get)
+        return descriptor.value;
+      return descriptor.get.call(self);
+    }
+    return undefined;
+  }
+  function superSet(self, homeObject, name, value) {
+    var descriptor = superDescriptor(homeObject, name);
+    if (descriptor && descriptor.set) {
+      descriptor.set.call(self, value);
+      return value;
+    }
+    throw $TypeError("super has no setter '" + name + "'.");
+  }
+  function getDescriptors(object) {
+    var descriptors = {},
+        name,
+        names = $getOwnPropertyNames(object);
+    for (var i = 0; i < names.length; i++) {
+      var name = names[i];
+      descriptors[name] = $getOwnPropertyDescriptor(object, name);
+    }
+    return descriptors;
+  }
+  function createClass(ctor, object, staticObject, superClass) {
+    $defineProperty(object, 'constructor', {
+      value: ctor,
+      configurable: true,
+      enumerable: false,
+      writable: true
+    });
+    if (arguments.length > 3) {
+      if (typeof superClass === 'function')
+        ctor.__proto__ = superClass;
+      ctor.prototype = $create(getProtoParent(superClass), getDescriptors(object));
+    } else {
+      ctor.prototype = object;
+    }
+    $defineProperty(ctor, 'prototype', {
+      configurable: false,
+      writable: false
+    });
+    return $defineProperties(ctor, getDescriptors(staticObject));
+  }
+  function getProtoParent(superClass) {
+    if (typeof superClass === 'function') {
+      var prototype = superClass.prototype;
+      if ($Object(prototype) === prototype || prototype === null)
+        return superClass.prototype;
+    }
+    if (superClass === null)
+      return null;
+    throw new $TypeError();
+  }
+  function defaultSuperCall(self, homeObject, args) {
+    if ($getPrototypeOf(homeObject) !== null)
+      superCall(self, homeObject, 'constructor', args);
+  }
+  $traceurRuntime.createClass = createClass;
+  $traceurRuntime.defaultSuperCall = defaultSuperCall;
+  $traceurRuntime.superCall = superCall;
+  $traceurRuntime.superGet = superGet;
+  $traceurRuntime.superSet = superSet;
+})();
+(function() {
+  'use strict';
+  var createPrivateName = $traceurRuntime.createPrivateName;
+  var $defineProperties = $traceurRuntime.defineProperties;
+  var $defineProperty = $traceurRuntime.defineProperty;
+  var $create = Object.create;
+  var $TypeError = TypeError;
+  function nonEnum(value) {
+    return {
+      configurable: true,
+      enumerable: false,
+      value: value,
+      writable: true
+    };
+  }
   var ST_NEWBORN = 0;
   var ST_EXECUTING = 1;
   var ST_SUSPENDED = 2;
@@ -389,7 +532,7 @@
     next: {enumerable: false},
     throw: {enumerable: false}
   });
-  defineProperty(GeneratorFunctionPrototype.prototype, Symbol.iterator, nonEnum(function() {
+  Object.defineProperty(GeneratorFunctionPrototype.prototype, Symbol.iterator, nonEnum(function() {
     return this;
   }));
   function createGeneratorInstance(innerFunction, functionObject, self) {
@@ -414,7 +557,7 @@
       ctx.reject = reject;
     });
   }
-  AsyncFunctionContext.prototype = Object.create(GeneratorContext.prototype);
+  AsyncFunctionContext.prototype = $create(GeneratorContext.prototype);
   AsyncFunctionContext.prototype.end = function() {
     switch (this.state) {
       case END_STATE:
@@ -469,135 +612,9 @@
     if (last.finallyFallThrough !== undefined)
       ctx.finallyFallThrough = last.finallyFallThrough;
   }
-  function setupGlobals(global) {
-    global.Symbol = Symbol;
-    polyfillObject(global.Object);
-  }
-  setupGlobals(global);
-  global.$traceurRuntime = {
-    assertObject: assertObject,
-    asyncWrap: asyncWrap,
-    exportStar: exportStar,
-    initGeneratorFunction: initGeneratorFunction,
-    createGeneratorInstance: createGeneratorInstance,
-    getOwnHashObject: getOwnHashObject,
-    setProperty: setProperty,
-    setupGlobals: setupGlobals,
-    toObject: toObject,
-    toProperty: toProperty,
-    type: types,
-    typeof: typeOf,
-    defineProperties: $defineProperties,
-    defineProperty: $defineProperty,
-    getOwnPropertyDescriptor: $getOwnPropertyDescriptor,
-    getOwnPropertyNames: $getOwnPropertyNames
-  };
-})(typeof global !== 'undefined' ? global : this);
-(function() {
-  'use strict';
-  var toObject = $traceurRuntime.toObject;
-  function spread() {
-    var rv = [],
-        k = 0;
-    for (var i = 0; i < arguments.length; i++) {
-      var valueToSpread = toObject(arguments[i]);
-      for (var j = 0; j < valueToSpread.length; j++) {
-        rv[k++] = valueToSpread[j];
-      }
-    }
-    return rv;
-  }
-  $traceurRuntime.spread = spread;
-})();
-(function() {
-  'use strict';
-  var $Object = Object;
-  var $TypeError = TypeError;
-  var $create = $Object.create;
-  var $defineProperties = $traceurRuntime.defineProperties;
-  var $defineProperty = $traceurRuntime.defineProperty;
-  var $getOwnPropertyDescriptor = $traceurRuntime.getOwnPropertyDescriptor;
-  var $getOwnPropertyNames = $traceurRuntime.getOwnPropertyNames;
-  var $getPrototypeOf = Object.getPrototypeOf;
-  function superDescriptor(homeObject, name) {
-    var proto = $getPrototypeOf(homeObject);
-    do {
-      var result = $getOwnPropertyDescriptor(proto, name);
-      if (result)
-        return result;
-      proto = $getPrototypeOf(proto);
-    } while (proto);
-    return undefined;
-  }
-  function superCall(self, homeObject, name, args) {
-    return superGet(self, homeObject, name).apply(self, args);
-  }
-  function superGet(self, homeObject, name) {
-    var descriptor = superDescriptor(homeObject, name);
-    if (descriptor) {
-      if (!descriptor.get)
-        return descriptor.value;
-      return descriptor.get.call(self);
-    }
-    return undefined;
-  }
-  function superSet(self, homeObject, name, value) {
-    var descriptor = superDescriptor(homeObject, name);
-    if (descriptor && descriptor.set) {
-      descriptor.set.call(self, value);
-      return value;
-    }
-    throw $TypeError("super has no setter '" + name + "'.");
-  }
-  function getDescriptors(object) {
-    var descriptors = {},
-        name,
-        names = $getOwnPropertyNames(object);
-    for (var i = 0; i < names.length; i++) {
-      var name = names[i];
-      descriptors[name] = $getOwnPropertyDescriptor(object, name);
-    }
-    return descriptors;
-  }
-  function createClass(ctor, object, staticObject, superClass) {
-    $defineProperty(object, 'constructor', {
-      value: ctor,
-      configurable: true,
-      enumerable: false,
-      writable: true
-    });
-    if (arguments.length > 3) {
-      if (typeof superClass === 'function')
-        ctor.__proto__ = superClass;
-      ctor.prototype = $create(getProtoParent(superClass), getDescriptors(object));
-    } else {
-      ctor.prototype = object;
-    }
-    $defineProperty(ctor, 'prototype', {
-      configurable: false,
-      writable: false
-    });
-    return $defineProperties(ctor, getDescriptors(staticObject));
-  }
-  function getProtoParent(superClass) {
-    if (typeof superClass === 'function') {
-      var prototype = superClass.prototype;
-      if ($Object(prototype) === prototype || prototype === null)
-        return superClass.prototype;
-    }
-    if (superClass === null)
-      return null;
-    throw new $TypeError();
-  }
-  function defaultSuperCall(self, homeObject, args) {
-    if ($getPrototypeOf(homeObject) !== null)
-      superCall(self, homeObject, 'constructor', args);
-  }
-  $traceurRuntime.createClass = createClass;
-  $traceurRuntime.defaultSuperCall = defaultSuperCall;
-  $traceurRuntime.superCall = superCall;
-  $traceurRuntime.superGet = superGet;
-  $traceurRuntime.superSet = superSet;
+  $traceurRuntime.asyncWrap = asyncWrap;
+  $traceurRuntime.initGeneratorFunction = initGeneratorFunction;
+  $traceurRuntime.createGeneratorInstance = createGeneratorInstance;
 })();
 (function() {
   function buildFromEncodedParts(opt_scheme, opt_userInfo, opt_domain, opt_port, opt_path, opt_queryData, opt_fragment) {
diff --git a/src/runtime/runtime.js b/src/runtime/runtime.js
index 8cafe7e2a..6eb61f298 100644
--- a/src/runtime/runtime.js
+++ b/src/runtime/runtime.js
@@ -391,244 +391,6 @@
     return x;
   }
 
-  // Generator states. Terminology roughly matches that of
-  //   http://wiki.ecmascript.org/doku.php?id=harmony:generators
-  // Since 'state' is already taken, use 'GState' instead to denote what's
-  // referred to as "G.[[State]]" on that page.
-  var ST_NEWBORN = 0;
-  var ST_EXECUTING = 1;
-  var ST_SUSPENDED = 2;
-  var ST_CLOSED = 3;
-
-  var END_STATE = -2;
-  var RETHROW_STATE = -3;
-
-
-  function getInternalError(state) {
-    return new Error('Traceur compiler bug: invalid state in state machine: ' +
-                      state);
-  }
-
-  function GeneratorContext() {
-    this.state = 0;
-    this.GState = ST_NEWBORN;
-    this.storedException = undefined;
-    this.finallyFallThrough = undefined;
-    this.sent_ = undefined;
-    this.returnValue = undefined;
-    this.tryStack_ = [];
-  }
-  GeneratorContext.prototype = {
-    pushTry: function(catchState, finallyState) {
-      if (finallyState !== null) {
-        var finallyFallThrough = null;
-        for (var i = this.tryStack_.length - 1; i >= 0; i--) {
-          if (this.tryStack_[i].catch !== undefined) {
-            finallyFallThrough = this.tryStack_[i].catch;
-            break;
-          }
-        }
-        if (finallyFallThrough === null)
-          finallyFallThrough = RETHROW_STATE;
-
-        this.tryStack_.push({
-          finally: finallyState,
-          finallyFallThrough: finallyFallThrough
-        });
-      }
-
-      if (catchState !== null) {
-        this.tryStack_.push({catch: catchState});
-      }
-    },
-    popTry: function() {
-      this.tryStack_.pop();
-    },
-    get sent() {
-      this.maybeThrow();
-      return this.sent_;
-    },
-    set sent(v) {
-      this.sent_ = v;
-    },
-    get sentIgnoreThrow() {
-      return this.sent_;
-    },
-    maybeThrow: function() {
-      if (this.action === 'throw') {
-        this.action = 'next';
-        throw this.sent_;
-      }
-    },
-    end: function() {
-      switch (this.state) {
-        case END_STATE:
-          return this;
-        case RETHROW_STATE:
-          throw this.storedException;
-        default:
-          throw getInternalError(this.state);
-      }
-    },
-    handleException: function(ex) {
-      this.GState = ST_CLOSED;
-      this.state = END_STATE;
-      throw ex;
-    }
-  };
-
-  function nextOrThrow(ctx, moveNext, action, x) {
-    switch (ctx.GState) {
-      case ST_EXECUTING:
-        throw new Error(`"${action}" on executing generator`);
-
-      case ST_CLOSED:
-        throw new Error(`"${action}" on closed generator`);
-
-      case ST_NEWBORN:
-        if (action === 'throw') {
-          ctx.GState = ST_CLOSED;
-          throw x;
-        }
-        if (x !== undefined)
-          throw $TypeError('Sent value to newborn generator');
-        // fall through
-
-      case ST_SUSPENDED:
-        ctx.GState = ST_EXECUTING;
-        ctx.action = action;
-        ctx.sent = x;
-        var value = moveNext(ctx);
-        var done = value === ctx;
-        if (done)
-          value = ctx.returnValue;
-        ctx.GState = done ? ST_CLOSED : ST_SUSPENDED;
-        return {value: value, done: done};
-    }
-  }
-
-  var ctxName = createPrivateName();
-  var moveNextName = createPrivateName();
-
-  function GeneratorFunction() {}
-
-  function GeneratorFunctionPrototype() {}
-
-  GeneratorFunction.prototype = GeneratorFunctionPrototype;
-
-  $defineProperty(GeneratorFunctionPrototype, 'constructor',
-      nonEnum(GeneratorFunction));
-
-  GeneratorFunctionPrototype.prototype = {
-    constructor: GeneratorFunctionPrototype,
-    next: function(v) {
-      return nextOrThrow(this[ctxName], this[moveNextName], 'next', v);
-    },
-    throw: function(v) {
-      return nextOrThrow(this[ctxName], this[moveNextName], 'throw', v);
-    }
-  };
-
-  $defineProperties(GeneratorFunctionPrototype.prototype, {
-    constructor: {enumerable: false},
-    next: {enumerable: false},
-    throw: {enumerable: false},
-  });
-
-  defineProperty(GeneratorFunctionPrototype.prototype, Symbol.iterator,
-      nonEnum(function() {
-        return this;
-      }));
-
-  function createGeneratorInstance(innerFunction, functionObject, self) {
-    // TODO(arv): Use [[GeneratorState]]
-    var moveNext = getMoveNext(innerFunction, self);
-    var ctx = new GeneratorContext();
-
-    var object = $create(functionObject.prototype);
-    object[ctxName] = ctx;
-    object[moveNextName] = moveNext;
-    return object;
-  }
-
-  function initGeneratorFunction(functionObject) {
-    functionObject.prototype = $create(GeneratorFunctionPrototype.prototype);
-    functionObject.__proto__ = GeneratorFunctionPrototype;
-    return functionObject;
-  }
-
-  function AsyncFunctionContext() {
-    GeneratorContext.call(this);
-    this.err = undefined;
-    var ctx = this;
-    ctx.result = new Promise(function(resolve, reject) {
-      ctx.resolve = resolve;
-      ctx.reject = reject;
-    });
-  }
-  AsyncFunctionContext.prototype = Object.create(GeneratorContext.prototype);
-  AsyncFunctionContext.prototype.end = function() {
-    switch (this.state) {
-      case END_STATE:
-        this.resolve(this.returnValue);
-        break;
-      case RETHROW_STATE:
-        this.reject(this.storedException);
-        break;
-      default:
-        this.reject(getInternalError(this.state));
-    }
-  };
-  AsyncFunctionContext.prototype.handleException = function() {
-    this.state = RETHROW_STATE;
-  };
-
-  function asyncWrap(innerFunction, self) {
-    var moveNext = getMoveNext(innerFunction, self);
-    var ctx = new AsyncFunctionContext();
-    ctx.createCallback = function(newState) {
-      return function (value) {
-        ctx.state = newState;
-        ctx.value = value;
-        moveNext(ctx);
-      };
-    }
-
-    ctx.errback = function(err) {
-      handleCatch(ctx, err);
-      moveNext(ctx);
-    };
-
-    moveNext(ctx);
-    return ctx.result;
-  }
-
-  function getMoveNext(innerFunction, self) {
-    return function(ctx) {
-      while (true) {
-        try {
-          return innerFunction.call(self, ctx);
-        } catch (ex) {
-          handleCatch(ctx, ex);
-        }
-      }
-    };
-  }
-
-  function handleCatch(ctx, ex) {
-    ctx.storedException = ex;
-    var last = ctx.tryStack_[ctx.tryStack_.length - 1];
-    if (!last) {
-      ctx.handleException(ex);
-      return;
-    }
-
-    ctx.state = last.catch !== undefined ? last.catch : last.finally;
-
-    if (last.finallyFallThrough !== undefined)
-      ctx.finallyFallThrough = last.finallyFallThrough;
-  }
-
   function setupGlobals(global) {
     global.Symbol = Symbol;
 
@@ -639,10 +401,8 @@
 
   global.$traceurRuntime = {
     assertObject: assertObject,
-    asyncWrap: asyncWrap,
+    createPrivateName: createPrivateName,
     exportStar: exportStar,
-    initGeneratorFunction: initGeneratorFunction,
-    createGeneratorInstance: createGeneratorInstance,
     getOwnHashObject: getOwnHashObject,
     setProperty: setProperty,
     setupGlobals: setupGlobals,