DevTools.hx

package ;

class DevTools {
  macro static public function measure(e, ?msg:String) {
    if (msg == null) 
      msg = haxe.macro.ExprTools.toString(e);
    return macro @:pos(e.pos) {
      var start = haxe.Timer.stamp(),
          result = [$e];//wrapping in the array skews the result a bit, but avoids issues with Void
      var duration = haxe.Timer.stamp() - start;
      trace($v{msg}+ ' took '+duration + ' seconds');//one could add some formatting here
      result[0];
    }
  }
}

Example.hx

package ;

import DevTools.*;

class Example {
  static function guessPi(?samples = 1000000) {
    var hits = 0;
    for (i in 0...samples) {
      var x = Math.random(),
          y = Math.random();
      if (x * x + y * y <= 1) hits++;
    }
    return hits / samples * 4;
  }
  static function main() {
    measure(trace('foo'));
    measure(for (i in 0...100000) {}, 'long loop');
    trace('PI is approximately '+measure(guessPi()));
  }
}