Source code

Revision control

Copy as Markdown

Other Tools

// Tests when JSOP_OPTIMIZE_SPREADCALL can't be applied during the initial
// Ion compilation.
// JSOP_OPTIMIZE_SPREADCALL can be optimised when the following conditions
// are fulfilled:
// (1) the argument is an array
// (2) the array has no hole
// (3) array[@@iterator] is not modified
// (4) the array's prototype is Array.prototype
// (5) Array.prototype[@@iterator] is not modified
// (6) %ArrayIteratorPrototype%.next is not modified
function add(a, b) {
return a + b;
}
// %ArrayIteratorPrototype%.next was modified.
function test() {
var ArrayIteratorPrototype = Object.getPrototypeOf(Array.prototype[Symbol.iterator]());
var ArrayIteratorPrototypeNext = ArrayIteratorPrototype.next;
ArrayIteratorPrototype.next = function() {
var res = ArrayIteratorPrototypeNext.call(this);
if (!res.done) {
res.value += 2;
}
return res;
};
function fn(...rest) {
return add(...rest);
}
for (var i = 0; i < 2000; ++i) {
assertEq(fn(1, 2), 7);
}
}
test();