ffi: fast buffer path leaks V8 handles on every optimized call #66866

import { dlopen } from 'node:ffi';

const { functions: { strlen } } = dlopen(null, {
  strlen: { arguments: ['buffer'], return: 'u64' },
});

const kind = process.argv[2] ?? 'view';
const ab = new ArrayBuffer(16); // zero-filled, so strlen() returns 0n
const arg = kind === 'arraybuffer' ? ab : new Uint8Array(ab);

function hot(x) { return strlen(x); }

const mb = () => Math.round(process.memoryUsage().rss / 2 ** 20);
const before = mb();
for (let i = 0; i < 2e7; i++) hot(arg);
console.log(`${kind}: rss ${before} MB -> ${mb()} MB after 2e7 calls`);