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Unified Diff: src/js/v8natives.js

Issue 1552473002: Revert of [runtime] Introduce dedicated JSBoundFunction to represent bound functions. (Closed) Base URL: https://chromium.googlesource.com/v8/v8.git@FunctionConstructor
Patch Set: Created 5 years ago
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Index: src/js/v8natives.js
diff --git a/src/js/v8natives.js b/src/js/v8natives.js
index 8a748a5ebf2ae24c2acdf685fac0dc73a0efd486..f57a89a9c0a57499ddcb1aa2e404f2a9672ad612 100644
--- a/src/js/v8natives.js
+++ b/src/js/v8natives.js
@@ -1236,10 +1236,80 @@
// ----------------------------------------------------------------------------
// 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.
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