649775 - TI: Crash in mjit-generated code

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[Christian Holler (:decoder)]

The following testcase crashes on TI rev a3eeee8f7803 (run with options -n -m -a), tested on 64 bit:

var x = [, ];
var n = [, ];
var np = 18229;
sa = Array;
function copy_(x, y) {
    var i;
    var k = x < y ? x.length : y.length;
    for (i = 0; i < k; i--)
        x[i];
}
function mont_(x, y, n, np) {
    copy_(x, sa);
}
mont_(x, x, n, np);

Comment 1

[Brian Hackett [Laid off!]]

Erk, array underflow from an incorrectly hoisted bounds check. Oops! We only accounted for the index variable increasing and overflowing the array, not decreasing and underflowing the array.

http://hg.mozilla.org/projects/jaegermonkey/rev/f3acaebac193

Comment 2

[Christian Holler (:decoder)]

A testcase for this bug was automatically identified at js/src/jit-test/tests/jaeger/bug649775.js.