evalFuncOpt.js

/**
 * Test V8 optimization against eval and new Function
 * Run with: node --allow-natives-syntax evalFuncOpt.js
 * More verbose with: node --trace_opt --trace_deopt --allow-natives-syntax evalFuncOpt.js
 * 
 * More info at: https://github.com/petkaantonov/bluebird/wiki/Optimization-killers
 */

function adder(a, b) {
    return new Function('a', 'b', 'return b%2 ? a + b : b%3 ? a - b : b%5 ? b / a : a * b')(a, b);
}
function addereval(a, b) {
    return eval('b%2 ? a + b : b%3 ? a - b : b%5 ? b / a : a * b');
}
var b = 0;
function printStatus(fn) {
    switch (%GetOptimizationStatus(fn)) {
        case 1: console.log(fn.name, "function is optimized"); break;
        case 2: console.log(fn.name, "function is not optimized"); break;
        case 3: console.log(fn.name, "function is always optimized"); break;
        case 4: console.log(fn.name, "function is never optimized"); break;
        case 6: console.log(fn.name, "function is maybe deoptimized"); break;
        case 7: console.log("Function is optimized by TurboFan"); break;
        default: console.log("Unknown optimization status"); break;
    }
}
adder(0, 1);
adder(2, 3);
%OptimizeFunctionOnNextCall(adder);
printStatus(adder);
adder(4, 5);
printStatus(adder);

addereval(0, 1);
addereval(2, 3);
%OptimizeFunctionOnNextCall(addereval);
printStatus(addereval);
addereval(4, 5);
printStatus(addereval);