Extract worklet logic from value unpacker

[tomekzaw]

Summary

This PR moves the logic behind creation of worklets from JS valueUnpacker directly into C++ ShareableWorklet::toJSValue.

It's a step towards removing valueUnpacker which has been causing some problems recently (see #5660).

Fixes #5445.

Test plan

App.tsx

import { StyleSheet, View, Button } from 'react-native';

import { runOnUI } from 'react-native-reanimated';
import React from 'react';

export default function EmptyExample() {
  const handlePress = () => {
    runOnUI(() => {
      console.log('Hello world!');
    })();
  };

  return (
    <View style={styles.container}>
      <Button title="ShareableWorklet" onPress={handlePress} />
    </View>
  );
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    alignItems: 'center',
    justifyContent: 'center',
  },
});

[tomekzaw]

Some performance measurements:

main debug 136360 us main release 86487 us

this PR debug 397071 us this PR release 242305 us

😢

[tjzel]

Haven't had the time to check it yet, but did you verify that the caches are actually utilized? Maybe that's the reason for performance issues.

[tomekzaw]

@tjzel You are right, it looks like after the changes the cache does not work as expected.

Before:

worklet hash: creation time
17031627990684: 109 us
17031627990684: 5 us
17031627990684: 3 us
17031627990684: 3 us
17031627990684: 3 us
17031627990684: 3 us
17031627990684: 3 us
17031627990684: 3 us

After:

worklet hash: creation time
17031627990684: 123 us
17031627990684: 110 us
17031627990684: 110 us
17031627990684: 108 us
17031627990684: 107 us
17031627990684: 107 us
17031627990684: 113 us
17031627990684: 106 us

[tomekzaw]

CWCT (cumulative worklet creation time)

#include <iostream>
#include <sstream>
#include <chrono>

using namespace std::chrono;

auto start = high_resolution_clock::now();
// ShareableWorklet::toJSValue
auto end = high_resolution_clock::now();
auto duration = duration_cast<microseconds>(end - start);
static unsigned long acc = 0;
acc += duration.count();
std::cout << static_cast<unsigned long long>(workletHash.asNumber()) << ": " << acc << " us" << std::endl;

	main	this PR
debug	122455 us	122862 us
release	82094 us	82824 us

So it's just a 1% slower 🥳

[tomekzaw]

WIT (worklet invocation time)

function worklet() {
  'worklet';
  // do nothing
}
runOnUI(() => {
  const start = performance.now();
  for (let i = 0; i < 10000000; i++) {
    worklet();
  }
  const end = performance.now();
  console.log(end - start, 'ms');
})();

	main	this PR
debug	373 ms	371 ms
release	347 ms	347 ms