feat(vm): threaded VM

fix-vm/src/stack.rs

@@ -1,76 +0,0 @@
-use std::mem::MaybeUninit;
-
-use gc_arena::Collect;
-
-pub(super) struct Stack<const N: usize, T> {
-    inner: Box<[MaybeUninit<T>; N]>,
-    len: usize,
-}
-
-unsafe impl<'gc, const N: usize, T: Collect<'gc> + 'gc> Collect<'gc> for Stack<N, T> {
-    const NEEDS_TRACE: bool = T::NEEDS_TRACE;
-    fn trace<U: gc_arena::collect::Trace<'gc>>(&self, cc: &mut U) {
-        for item in self.inner[..self.len].iter() {
-            unsafe {
-                item.assume_init_ref().trace(cc);
-            }
-        }
-    }
-}
-
-impl<const N: usize, T> Default for Stack<N, T> {
-    fn default() -> Self {
-        Self::new()
-    }
-}
-
-impl<const N: usize, T> Stack<N, T> {
-    pub(super) fn new() -> Self {
-        Self {
-            inner: Box::new([const { MaybeUninit::uninit() }; N]),
-            len: 0,
-        }
-    }
-
-    pub(super) fn push(&mut self, val: T) -> Result<(), T> {
-        if self.len == N {
-            return Err(val);
-        }
-        unsafe {
-            self.inner.get_unchecked_mut(self.len).write(val);
-        }
-        self.len += 1;
-        Ok(())
-    }
-
-    pub(super) fn pop(&mut self) -> Option<T> {
-        if self.len == 0 {
-            return None;
-        }
-        let ret = unsafe {
-            self.inner
-                .get_unchecked_mut(self.len - 1)
-                .assume_init_read()
-        };
-        self.len -= 1;
-        Some(ret)
-    }
-
-    pub(super) fn tos(&self) -> Option<&T> {
-        if self.len == 0 {
-            return None;
-        }
-        Some(unsafe { self.inner.get_unchecked(self.len - 1).assume_init_ref() })
-    }
-
-    pub(super) fn tos_mut(&mut self) -> Option<&mut T> {
-        if self.len == 0 {
-            return None;
-        }
-        Some(unsafe { self.inner.get_unchecked_mut(self.len - 1).assume_init_mut() })
-    }
-
-    pub(super) fn len(&self) -> usize {
-        self.len
-    }
-}

fix-vm/src/value.rs

@@ -263,11 +263,11 @@ impl<'gc> Value<'gc> {
     }
 
     #[inline]
-    pub(crate) fn restrict(self) -> Option<StrictValue<'gc>> {
-        if !self.is::<Thunk<'gc>>() {
-            Some(StrictValue(self))
+    pub(crate) fn restrict(self) -> Result<StrictValue<'gc>, Gc<'gc, Thunk<'gc>>> {
+        if let Some(thunk) = self.as_gc::<Thunk<'gc>>() {
+            Err(thunk)
         } else {
-            None
+            Ok(StrictValue(self))
         }
     }
 }
@@ -462,7 +462,7 @@ pub(crate) enum ThunkState<'gc> {
         arg: Value<'gc>,
     },
     Blackhole,
-    Evaluated(Value<'gc>),
+    Evaluated(StrictValue<'gc>),
 }
 
 #[derive(Collect, Debug)]