You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: stack_creator.rs
    path of file: ./repos/wasmtime/tests/all
    
    the code of the file until where you have to start completion: #![cfg(all(not(target_os = "windows"), not(miri)))]
use anyhow::{bail, Context};
use std::{
    alloc::{GlobalAlloc, Layout, System},
    ops::Range,
    ptr::NonNull,
    sync::Arc,
};
use wasmtime::*;

fn align_up(v: usize, align: usize) -> usize {
    return (v + (align - 1)) & 
    
    fn new_stack(&self, size: usize) -> Result<Box<dyn StackMemory>> {
        if size != self.size {
            bail!("must use the size we allocated for this stack memory creator");
        }
        let page_size = rustix::param::page_size();
        // skip over the page size
        let base_ptr = unsafe { self.memory.as_ptr().add(page_size) };
        let base = NonNull::new(base_ptr).context("unable to compute stack base")?;
        Ok(Box::new(CustomStack::new(base, self.size)))
    }