[es6] implement Reflect.apply() & Reflect.construct()

src/runtime.js

 // Copyright 2006-2008 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.
 
 // This files contains runtime support implemented in JavaScript.
 
 // CAUTION: Some of the functions specified in this file are called
 // directly from compiled code. These are the functions with names in
 // ALL CAPS. The compiled code passes the first argument in 'this'.
 
@@ skipping 431 matching lines @@
   if (args != null && !IS_SPEC_OBJECT(args)) {
     throw %MakeTypeError('apply_wrong_args', []);
   }
 
   // Return the length which is the number of arguments to copy to the
   // stack. It is guaranteed to be a small integer at this point.
   return length;
 }
 
 
+function REFLECT_APPLY_PREPARE(args) {
+  var length;
+  // First check whether length is a positive Smi and args is an
+  // array. This is the fast case. If this fails, we do the slow case
+  // that takes care of more eventualities.
+  if (IS_ARRAY(args)) {
+    length = args.length;
+    if (%_IsSmi(length) && length >= 0 && length < 0x800000 &&
+        IS_SPEC_FUNCTION(this)) {
+      return length;
+    }
+  }
+
+  if (!IS_SPEC_FUNCTION(this)) {
+    throw %MakeTypeError('called_non_callable', [ %ToString(this) ]);
+  }
+
+  if (!IS_SPEC_OBJECT(args)) {
+    throw %MakeTypeError('reflect_apply_wrong_args', [ ]);
+  }
+
+  length = %ToLength(args.length);
+
+  // We can handle any number of apply arguments if the stack is
+  // big enough, but sanity check the value to avoid overflow when
+  // multiplying with pointer size.
+  if (length > 0x800000) {

[arv (Not doing code reviews), 2015/03/03 14:25:52]

maybe add a const/macro for this?

[caitp (gmail), 2015/03/03 15:53:49]

Replaced the magic number with a macro, hows that?

+    throw %MakeRangeError('stack_overflow', []);
+  }
+
+  // Return the length which is the number of arguments to copy to the
+  // stack. It is guaranteed to be a small integer at this point.
+  return length;
+}
+
+
+function REFLECT_CONSTRUCT_PREPARE(args, newTarget) {
+  var length;
+  var ctorOk = IS_SPEC_FUNCTION(this) && %IsConstructor(this);
+  var newTargetOk = IS_SPEC_FUNCTION(newTarget) && %IsConstructor(newTarget);
+
+  // First check whether length is a positive Smi and args is an
+  // array. This is the fast case. If this fails, we do the slow case
+  // that takes care of more eventualities.
+  if (IS_ARRAY(args)) {
+    length = args.length;
+    if (%_IsSmi(length) && length >= 0 && length < 0x800000 &&
+        ctorOk && newTargetOk) {
+      return length;
+    }
+  }
+
+  if (!ctorOk) {
+    if (!IS_SPEC_FUNCTION(this)) {
+      throw %MakeTypeError('called_non_callable', [ %ToString(this) ]);
+    } else {
+      throw %MakeTypeError('not_constructor', [ %ToString(this) ]);
+    }
+  }
+
+  if (!newTargetOk) {
+    if (!IS_SPEC_FUNCTION(newTarget)) {
+      throw %MakeTypeError('called_non_callable', [ %ToString(newTarget) ]);
+    } else {
+      throw %MakeTypeError('not_constructor', [ %ToString(newTarget) ]);
+    }
+  }
+
+  if (!IS_SPEC_OBJECT(args)) {
+    throw %MakeTypeError('reflect_construct_wrong_args', [ ]);
+  }
+
+  length = %ToLength(args.length);
+
+  // We can handle any number of apply arguments if the stack is
+  // big enough, but sanity check the value to avoid overflow when
+  // multiplying with pointer size.
+  if (length > 0x800000) {
+    throw %MakeRangeError('stack_overflow', []);
+  }
+
+  // Return the length which is the number of arguments to copy to the
+  // stack. It is guaranteed to be a small integer at this point.
+  return length;
+}
+
+
 function STACK_OVERFLOW(length) {
   throw %MakeRangeError('stack_overflow', []);
 }
 
 
 // Convert the receiver to an object - forward to ToObject.
 function TO_OBJECT() {
   return %ToObject(this);
 }
 
@@ skipping 225 matching lines @@
   return i;
 }
 
 
 // NOTE: Setting the prototype for Array must take place as early as
 // possible due to code generation for array literals.  When
 // generating code for a array literal a boilerplate array is created
 // that is cloned when running the code.  It is essential that the
 // boilerplate gets the right prototype.
 %FunctionSetPrototype($Array, new $Array(0));