V8 checks

checks.js

exports.fastElements = function(obj) {
    if (%HasFastSmiElements(obj)) {
        console.log('Fast SMI elements');
    }
    if (%HasFastSmiOrObjectElements(obj)) {
        console.log('Fast SMI or Object elements');
    }
    if (%HasFastObjectElements(obj)) {
        console.log('Fast Object elements');
    }
    if (%HasFastDoubleElements(obj)) {
        console.log('Fast double elements');
    }
    if (%HasFastHoleyElements(obj)) {
        console.log('Fast holey elements');
    }
};

exports.smi = function(x) {
  %_IsSmi(x) ?
    console.log('X is SMI') :
    console.log('X is not SMI');
};

exports.funcOptimization = function(fn) {
    switch(%GetOptimizationStatus(fn)) {
        case 1:
            console.log('Function is optimized');
            break;
        case 2:
            console.log('Function is not optimized');
            break;
        case 3:
            console.log('Function is always optimized');
            break;
        case 4:
            console.log('Function is never optimized');
            break;
        case 6:
            console.log('Function is maybe deoptimized');
            break;
    }
};