Detect root objects in WASM stack

[myuon]

quartz/quartz/generator.qz

Line 747 in 90131ad

// FIXME: this is broken at 2.8.1

[myuon]

How about pushing to stack at every t_make or t_record, instead of t_let?

Or, at every function call of alloc_with_rep

[myuon]

fun f() {
  let k = make[vec[i32]]();

  return k;
}

fun g() {
  let l = f();
}

[myuon]

Observation: We only need to find the locals and get their values.

fun f() {
  let k = make[vec[i32]]();
  let h = make[vec[i32]]();
 
  return k;
}

fun g() {
  let l = f();

unwind:
  stack_push(l);

  perform_gc();
}

fun recursive(i: vec[i32]) {
  let k = make[vec[i32]]();
  
unwind:
  stack_push(k);

  recursive(k);
}

[myuon]

Or we should avoid using local variables, push everything to memory, which solves this issue

[myuon]

We need to do this:

• push all local variables to stack before function call
• push all local variables just before calling perform_gc