getCache = (associate, path) => {
	let o = cacheMap.get(associate);
	if (o === undefined) {
		o = new Map();
		cacheMap.set(associate, o);
	}
	let c = o.get(path);
	if (c === undefined) {
		c = { counter: 0 };
		o.set(path, c);
	}
	return c;
}
@param {Compiler} associate associate
@param {string} path path
@returns {{ counter: number }} result