Revert of [runtime] Introduce dedicated JSBoundFunction to represent bound functions.

src/js/v8natives.js

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 (function(global, utils) {
 
 %CheckIsBootstrapping();
 
 // ----------------------------------------------------------------------------
 // Imports
@@ skipping 1218 matching lines @@
   "parseInt", GlobalParseInt,
   "parseFloat", GlobalParseFloat
 ]);
 
 %SetForceInlineFlag(NumberIsNaN);
 
 
 // ----------------------------------------------------------------------------
 // Function
 
+// ES6 9.2.3.2 Function.prototype.bind(thisArg , ...args)
+function FunctionBind(this_arg) { // Length is 1.
+  if (!IS_CALLABLE(this)) throw MakeTypeError(kFunctionBind);
+
+  var boundFunction = function () {
+    // Poison .arguments and .caller, but is otherwise not detectable.
+    "use strict";
+    // This function must not use any object literals (Object, Array, RegExp),
+    // since the literals-array is being used to store the bound data.
+    if (!IS_UNDEFINED(new.target)) {
+      return %NewObjectFromBound(boundFunction);
+    }
+    var bindings = %BoundFunctionGetBindings(boundFunction);
+
+    var argc = %_ArgumentsLength();
+    if (argc == 0) {
+      return %Apply(bindings[0], bindings[1], bindings, 2, bindings.length - 2);
+    }
+    if (bindings.length === 2) {
+      return %Apply(bindings[0], bindings[1], arguments, 0, argc);
+    }
+    var bound_argc = bindings.length - 2;
+    var argv = new InternalArray(bound_argc + argc);
+    for (var i = 0; i < bound_argc; i++) {
+      argv[i] = bindings[i + 2];
+    }
+    for (var j = 0; j < argc; j++) {
+      argv[i++] = %_Arguments(j);
+    }
+    return %Apply(bindings[0], bindings[1], argv, 0, bound_argc + argc);
+  };
+
+  var proto = %_GetPrototype(this);  // in ES6 9.4.1.3 BoundFunctionCreate
+
+  var new_length = 0;
+  if (ObjectGetOwnPropertyDescriptor(this, "length") !== UNDEFINED) {
+    var old_length = this.length;
+    if (IS_NUMBER(old_length)) {
+      var argc = %_ArgumentsLength();
+      if (argc > 0) argc--;  // Don't count the thisArg as parameter.
+      new_length = TO_INTEGER(old_length) - argc;
+      if (new_length < 0) new_length = 0;
+    }
+  }
+
+  // This runtime function finds any remaining arguments on the stack,
+  // so we don't pass the arguments object.
+  var result = %FunctionBindArguments(boundFunction, this, this_arg,
+                                      new_length, proto);
+
+  var name = this.name;
+  var bound_name = IS_STRING(name) ? name : "";
+  %DefineDataPropertyUnchecked(result, "name", "bound " + bound_name,
+                               DONT_ENUM | READ_ONLY);
+
+  // We already have caller and arguments properties on functions,
+  // which are non-configurable. It therefore makes no sence to
+  // try to redefine these as defined by the spec. The spec says
+  // that bind should make these throw a TypeError if get or set
+  // is called and make them non-enumerable and non-configurable.
+  // To be consistent with our normal functions we leave this as it is.
+  // TODO(lrn): Do set these to be thrower.
+  return result;
+}
+
+
 // ----------------------------------------------------------------------------
 
 %AddNamedProperty(GlobalFunction.prototype, "constructor", GlobalFunction,
                   DONT_ENUM);
 
+utils.InstallFunctions(GlobalFunction.prototype, DONT_ENUM, [
+  "bind", FunctionBind,
+]);
+
 // ----------------------------------------------------------------------------
 // Iterator related spec functions.
 
 // ES6 7.4.1 GetIterator(obj, method)
 function GetIterator(obj, method) {
   if (IS_UNDEFINED(method)) {
     method = obj[iteratorSymbol];
   }
   if (!IS_CALLABLE(method)) {
     throw MakeTypeError(kNotIterable, obj);
@@ skipping 21 matching lines @@
   to.ObjectIsFrozen = ObjectIsFrozen;
   to.ObjectIsSealed = ObjectIsSealed;
   to.ObjectKeys = ObjectKeys;
 });
 
 %InstallToContext([
   "object_value_of", ObjectValueOf,
 ]);
 
 })