Flash / Actionscript CPU profiler

Question

Have you found such a tool and used it successfully?

Answer 1

I was also looking for a profiler for AS, but I wanted an freeware/open source solution that works with FlashDevelop and Flex SDK. I found none. So I wrote a simple python script and an even simpler AS class. The script essentially takes any AS file and adds profiling code (i.e. calls to measure the total runtime of that function with an accuracy of 1 ms - the resolution of the flash.utils.getTimer() call) to each function definition. The script sometimes makes mistakes, but these are usually easy to fix by hand. Then you need to add one more line manually: dump the profiling statistics somewhere at some point. This method is obviously far from accurate, but it nonetheless gives you good feel of bottlenecks in your code. I used it for a 100k file with success.

Here is the AS class:

package  {
    public class Profiler {
        private static var instance:Profiler;

        public static function get profiler():Profiler {
            if (!Profiler.instance) Profiler.instance = new Profiler;
            return Profiler.instance;
        }

        private var data:Object = {};

        public function profile(fn:String, dur:int):void {
            if (!data.hasOwnProperty(fn)) data[fn] = new Number(0);
            data[fn] += dur / 1000.0;
        }

        public function clear():void {
            data = { };
        }

        public function get stats():String {
            var st:String = "";
            for (var fn:String in data) {
                st += fn + ":\t" + data[fn] + "\n";
            }
            return st;
        }
    }
}

And here is the python script that does the trick:

import sre, sys

rePOI = sre.compile(r'''\bclass\b|\bfunction\b|\breturn\b|["'/{}]''')
reFun = sre.compile(r'\bfunction\b\s*((?:[gs]et\s+)?\w*)\s*\(')
reCls = sre.compile(r'class\s+(\w+)[\s{]')
reStr = sre.compile(r'''(["'/]).*?(?<!\\)\1''')

def addProfilingCalls(body):
    stack = []
    pos = 0
    depth = 0
    retvar = 0
    klass = ""
    match = rePOI.search(body, pos)
    while match:
        poi = match.group(0)
        pos = match.start(0)
        endpos = match.end(0)

        if poi in '''"'/''':
            strm = reStr.match(body, pos)
            if strm and (poi != '/' or sre.search('[=(,]\s*$', body[:pos])):
                endpos = strm.end(0)

        elif poi == 'class':
            klass = reCls.match(body, pos).group(1)
            sys.stderr.write('class ' + klass + '\n')

        elif poi == 'function':
            fname = reFun.match(body, pos)
            if fname.group(1):
                fname = klass + '.' + fname.group(1)
            else:
                lastf = stack[-1]
                lastf['anon'] += 1
                fname = lastf['name'] + '.anon' + str(lastf['anon'])
            sys.stderr.write('function ' + fname + '\n')
            stack.append({'name':fname, 'depth':depth, 'anon':0})

            brace = body.find('{', pos) + 1
            line = "\nvar __start__:int = flash.utils.getTimer();"
            body = body[:brace] + line + body[brace:]
            depth += 1
            endpos = brace + len(line)

        elif poi == '{':
            depth += 1

        elif poi == 'return':
            lastf = stack[-1]
            semicolon = body.find(';', pos) + 1
            if sre.match('return\s*;', body[pos:]):
                line = "{ Profiler.profiler.profile('" + lastf['name'] + \
                       "', flash.utils.getTimer() - __start__); return; }"
            else:
                retvar += 1
                line = "{ var __ret" + str(retvar) + "__:* =" + body[pos+6:semicolon] + \
                       "\nProfiler.profiler.profile('" + lastf['name'] + \
                       "', flash.utils.getTimer() - __start__); return __ret" + str(retvar) + "__; }"
            body = body[:pos] + line + body[semicolon:]
            endpos = pos + len(line)

        elif poi == '}':
            depth -= 1
            if len(stack) > 0 and stack[-1]['depth'] == depth:
                lastf = stack.pop()
                line = "Profiler.profiler.profile('" + lastf['name'] + \
                    "', flash.utils.getTimer() - __start__);\n"
                body = body[:pos] + line + body[pos:]
                endpos += len(line)

        pos = endpos
        match = rePOI.search(body, pos)
    return body

def main():
    if len(sys.argv) >= 2: inf = open(sys.argv[1], 'rU')
    else: inf = sys.stdin
    if len(sys.argv) >= 3: outf = open(sys.argv[2], 'wU')
    else: outf = sys.stdout
    outf.write(addProfilingCalls(inf.read()))
    inf.close()
    outf.close()

if __name__ == "__main__":
    main()

Feel free to use, distribute and modify both.