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use crate::runtime::vm::TableElement;
use crate::store::{AutoAssertNoGc, StoreOpaque};
use crate::{
prelude::*, AnyRef, ArrayRef, AsContext, AsContextMut, ExternRef, Func, HeapType, RefType,
Rooted, RootedGcRefImpl, StructRef, ValType, V128,
};
use core::ptr;
pub use crate::runtime::vm::ValRaw;
/// Possible runtime values that a WebAssembly module can either consume or
/// produce.
///
/// Note that we inline the `enum Ref { ... }` variants into `enum Val { ... }`
/// here as a size optimization.
#[derive(Debug, Clone, Copy)]
pub enum Val {
// NB: the ordering here is intended to match the ordering in
// `ValType` to improve codegen when learning the type of a value.
//
/// A 32-bit integer.
I32(i32),
/// A 64-bit integer.
I64(i64),
/// A 32-bit float.
///
/// Note that the raw bits of the float are stored here, and you can use
/// `f32::from_bits` to create an `f32` value.
F32(u32),
/// A 64-bit float.
///
/// Note that the raw bits of the float are stored here, and you can use
/// `f64::from_bits` to create an `f64` value.
F64(u64),
/// A 128-bit number.
V128(V128),
/// A function reference.
FuncRef(Option<Func>),
/// An external reference.
ExternRef(Option<Rooted<ExternRef>>),
/// An internal reference.
AnyRef(Option<Rooted<AnyRef>>),
}
macro_rules! accessors {
($bind:ident $(($variant:ident($ty:ty) $get:ident $unwrap:ident $cvt:expr))*) => ($(
/// Attempt to access the underlying value of this `Val`, returning
/// `None` if it is not the correct type.
#[inline]
pub fn $get(&self) -> Option<$ty> {
if let Val::$variant($bind) = self {
Some($cvt)
} else {
None
}
}
/// Returns the underlying value of this `Val`, panicking if it's the
/// wrong type.
///
/// # Panics
///
/// Panics if `self` is not of the right type.
#[inline]
pub fn $unwrap(&self) -> $ty {
self.$get().expect(concat!("expected ", stringify!($ty)))
}
)*)
}
impl Val {
/// Returns the null reference for the given heap type.
#[inline]
pub fn null_ref(heap_type: &HeapType) -> Val {
Ref::null(&heap_type).into()
}
/// Returns the null function reference value.
///
/// The return value has type `(ref null nofunc)` aka `nullfuncref` and is a
/// subtype of all function references.
#[inline]
pub const fn null_func_ref() -> Val {
Val::FuncRef(None)
}
/// Returns the null function reference value.
///
/// The return value has type `(ref null extern)` aka `nullexternref` and is
/// a subtype of all external references.
#[inline]
pub const fn null_extern_ref() -> Val {
Val::ExternRef(None)
}
/// Returns the null function reference value.
///
/// The return value has type `(ref null any)` aka `nullref` and is a
/// subtype of all internal references.
#[inline]
pub const fn null_any_ref() -> Val {
Val::AnyRef(None)
}
/// Returns the default value for the given type, if any exists.
///
/// Returns `None` if there is no default value for the given type (for
/// example, non-nullable reference types do not have a default value).
pub fn default_for_ty(ty: &ValType) -> Option<Val> {
match ty {
ValType::I32 => Some(Val::I32(0)),
ValType::I64 => Some(Val::I64(0)),
ValType::F32 => Some(Val::F32(0)),
ValType::F64 => Some(Val::F64(0)),
ValType::V128 => Some(Val::V128(V128::from(0))),
ValType::Ref(ref_ty) => {
if ref_ty.is_nullable() {
Some(Val::null_ref(ref_ty.heap_type()))
} else {
None
}
}
}
}
/// Returns the corresponding [`ValType`] for this `Val`.
///
/// # Errors
///
/// Returns an error if this value is a GC reference that has since been
/// unrooted.
///
/// # Panics
///
/// Panics if this value is associated with a different store.
#[inline]
pub fn ty(&self, store: impl AsContext) -> Result<ValType> {
self.load_ty(&store.as_context().0)
}
#[inline]
pub(crate) fn load_ty(&self, store: &StoreOpaque) -> Result<ValType> {
Ok(match self {
Val::I32(_) => ValType::I32,
Val::I64(_) => ValType::I64,
Val::F32(_) => ValType::F32,
Val::F64(_) => ValType::F64,
Val::V128(_) => ValType::V128,
Val::ExternRef(Some(_)) => ValType::EXTERNREF,
Val::ExternRef(None) => ValType::NULLFUNCREF,
Val::FuncRef(None) => ValType::NULLFUNCREF,
Val::FuncRef(Some(f)) => ValType::Ref(RefType::new(
false,
HeapType::ConcreteFunc(f.load_ty(store)),
)),
Val::AnyRef(None) => ValType::NULLREF,
Val::AnyRef(Some(a)) => ValType::Ref(RefType::new(false, a._ty(store)?)),
})
}
/// Does this value match the given type?
///
/// Returns an error is an underlying `Rooted` has been unrooted.
///
/// # Panics
///
/// Panics if this value is not associated with the given store.
pub fn matches_ty(&self, store: impl AsContext, ty: &ValType) -> Result<bool> {
self._matches_ty(&store.as_context().0, ty)
}
pub(crate) fn _matches_ty(&self, store: &StoreOpaque, ty: &ValType) -> Result<bool> {
assert!(self.comes_from_same_store(store));
assert!(ty.comes_from_same_engine(store.engine()));
Ok(match (self, ty) {
(Val::I32(_), ValType::I32)
| (Val::I64(_), ValType::I64)
| (Val::F32(_), ValType::F32)
| (Val::F64(_), ValType::F64)
| (Val::V128(_), ValType::V128) => true,
(Val::FuncRef(f), ValType::Ref(ref_ty)) => Ref::from(*f)._matches_ty(store, ref_ty)?,
(Val::ExternRef(e), ValType::Ref(ref_ty)) => {
Ref::from(*e)._matches_ty(store, ref_ty)?
}
(Val::AnyRef(a), ValType::Ref(ref_ty)) => Ref::from(*a)._matches_ty(store, ref_ty)?,
(Val::I32(_), _)
| (Val::I64(_), _)
| (Val::F32(_), _)
| (Val::F64(_), _)
| (Val::V128(_), _)
| (Val::FuncRef(_), _)
| (Val::ExternRef(_), _)
| (Val::AnyRef(_), _) => false,
})
}
pub(crate) fn ensure_matches_ty(&self, store: &StoreOpaque, ty: &ValType) -> Result<()> {
if !self.comes_from_same_store(store) {
bail!("value used with wrong store")
}
if !ty.comes_from_same_engine(store.engine()) {
bail!("type used with wrong engine")
}
if self._matches_ty(store, ty)? {
Ok(())
} else {
let actual_ty = self.load_ty(store)?;
bail!("type mismatch: expected {ty}, found {actual_ty}")
}
}
/// Convenience method to convert this [`Val`] into a [`ValRaw`].
///
/// Returns an error if this value is a GC reference and the GC reference
/// has been unrooted.
///
/// # Unsafety
///
/// This method is unsafe for the reasons that [`ExternRef::to_raw`] and
/// [`Func::to_raw`] are unsafe.
pub unsafe fn to_raw(&self, store: impl AsContextMut) -> Result<ValRaw> {
match self {
Val::I32(i) => Ok(ValRaw::i32(*i)),
Val::I64(i) => Ok(ValRaw::i64(*i)),
Val::F32(u) => Ok(ValRaw::f32(*u)),
Val::F64(u) => Ok(ValRaw::f64(*u)),
Val::V128(b) => Ok(ValRaw::v128(b.as_u128())),
Val::ExternRef(e) => Ok(ValRaw::externref(match e {
None => 0,
Some(e) => e.to_raw(store)?,
})),
Val::AnyRef(e) => Ok(ValRaw::anyref(match e {
None => 0,
Some(e) => e.to_raw(store)?,
})),
Val::FuncRef(f) => Ok(ValRaw::funcref(match f {
Some(f) => f.to_raw(store),
None => ptr::null_mut(),
})),
}
}
/// Convenience method to convert a [`ValRaw`] into a [`Val`].
///
/// # Unsafety
///
/// This method is unsafe for the reasons that [`ExternRef::from_raw`] and
/// [`Func::from_raw`] are unsafe. Additionally there's no guarantee
/// otherwise that `raw` should have the type `ty` specified.
pub unsafe fn from_raw(mut store: impl AsContextMut, raw: ValRaw, ty: ValType) -> Val {
let mut store = AutoAssertNoGc::new(store.as_context_mut().0);
Self::_from_raw(&mut store, raw, &ty)
}
pub(crate) unsafe fn _from_raw(
store: &mut AutoAssertNoGc<'_>,
raw: ValRaw,
ty: &ValType,
) -> Val {
match ty {
ValType::I32 => Val::I32(raw.get_i32()),
ValType::I64 => Val::I64(raw.get_i64()),
ValType::F32 => Val::F32(raw.get_f32()),
ValType::F64 => Val::F64(raw.get_f64()),
ValType::V128 => Val::V128(raw.get_v128().into()),
ValType::Ref(ref_ty) => {
let ref_ = match ref_ty.heap_type() {
HeapType::Func | HeapType::ConcreteFunc(_) => {
Func::_from_raw(store, raw.get_funcref()).into()
}
HeapType::NoFunc => Ref::Func(None),
HeapType::Extern => ExternRef::_from_raw(store, raw.get_externref()).into(),
HeapType::NoExtern => Ref::Extern(None),
HeapType::Any
| HeapType::Eq
| HeapType::I31
| HeapType::Array
| HeapType::ConcreteArray(_)
| HeapType::Struct
| HeapType::ConcreteStruct(_) => {
AnyRef::_from_raw(store, raw.get_anyref()).into()
}
HeapType::None => Ref::Any(None),
};
assert!(
ref_ty.is_nullable() || !ref_.is_null(),
"if the type is not nullable, we shouldn't get null; got \
type = {ref_ty}, ref = {ref_:?}"
);
ref_.into()
}
}
}
accessors! {
e
(I32(i32) i32 unwrap_i32 *e)
(I64(i64) i64 unwrap_i64 *e)
(F32(f32) f32 unwrap_f32 f32::from_bits(*e))
(F64(f64) f64 unwrap_f64 f64::from_bits(*e))
(FuncRef(Option<&Func>) func_ref unwrap_func_ref e.as_ref())
(ExternRef(Option<&Rooted<ExternRef>>) extern_ref unwrap_extern_ref e.as_ref())
(AnyRef(Option<&Rooted<AnyRef>>) any_ref unwrap_any_ref e.as_ref())
(V128(V128) v128 unwrap_v128 *e)
}
/// Get this value's underlying reference, if any.
#[inline]
pub fn ref_(self) -> Option<Ref> {
match self {
Val::FuncRef(f) => Some(Ref::Func(f)),
Val::ExternRef(e) => Some(Ref::Extern(e)),
Val::AnyRef(a) => Some(Ref::Any(a)),
Val::I32(_) | Val::I64(_) | Val::F32(_) | Val::F64(_) | Val::V128(_) => None,
}
}
/// Attempt to access the underlying `externref` value of this `Val`.
///
/// If this is not an `externref`, then `None` is returned.
///
/// If this is a null `externref`, then `Some(None)` is returned.
///
/// If this is a non-null `externref`, then `Some(Some(..))` is returned.
#[inline]
pub fn externref(&self) -> Option<Option<&Rooted<ExternRef>>> {
match self {
Val::ExternRef(None) => Some(None),
Val::ExternRef(Some(e)) => Some(Some(e)),
_ => None,
}
}
/// Returns the underlying `externref` value of this `Val`, panicking if it's the
/// wrong type.
///
/// If this is a null `externref`, then `None` is returned.
///
/// If this is a non-null `externref`, then `Some(..)` is returned.
///
/// # Panics
///
/// Panics if `self` is not a (nullable) `externref`.
#[inline]
pub fn unwrap_externref(&self) -> Option<&Rooted<ExternRef>> {
self.externref().expect("expected externref")
}
/// Attempt to access the underlying `anyref` value of this `Val`.
///
/// If this is not an `anyref`, then `None` is returned.
///
/// If this is a null `anyref`, then `Some(None)` is returned.
///
/// If this is a non-null `anyref`, then `Some(Some(..))` is returned.
#[inline]
pub fn anyref(&self) -> Option<Option<&Rooted<AnyRef>>> {
match self {
Val::AnyRef(None) => Some(None),
Val::AnyRef(Some(e)) => Some(Some(e)),
_ => None,
}
}
/// Returns the underlying `anyref` value of this `Val`, panicking if it's the
/// wrong type.
///
/// If this is a null `anyref`, then `None` is returned.
///
/// If this is a non-null `anyref`, then `Some(..)` is returned.
///
/// # Panics
///
/// Panics if `self` is not a (nullable) `anyref`.
#[inline]
pub fn unwrap_anyref(&self) -> Option<&Rooted<AnyRef>> {
self.anyref().expect("expected anyref")
}
/// Attempt to access the underlying `funcref` value of this `Val`.
///
/// If this is not an `funcref`, then `None` is returned.
///
/// If this is a null `funcref`, then `Some(None)` is returned.
///
/// If this is a non-null `funcref`, then `Some(Some(..))` is returned.
#[inline]
pub fn funcref(&self) -> Option<Option<&Func>> {
match self {
Val::FuncRef(None) => Some(None),
Val::FuncRef(Some(f)) => Some(Some(f)),
_ => None,
}
}
/// Returns the underlying `funcref` value of this `Val`, panicking if it's the
/// wrong type.
///
/// If this is a null `funcref`, then `None` is returned.
///
/// If this is a non-null `funcref`, then `Some(..)` is returned.
///
/// # Panics
///
/// Panics if `self` is not a (nullable) `funcref`.
#[inline]
pub fn unwrap_funcref(&self) -> Option<&Func> {
self.funcref().expect("expected funcref")
}
#[inline]
pub(crate) fn comes_from_same_store(&self, store: &StoreOpaque) -> bool {
match self {
Val::FuncRef(Some(f)) => f.comes_from_same_store(store),
Val::FuncRef(None) => true,
Val::ExternRef(Some(x)) => x.comes_from_same_store(store),
Val::ExternRef(None) => true,
Val::AnyRef(Some(a)) => a.comes_from_same_store(store),
Val::AnyRef(None) => true,
// Integers, floats, and vectors have no association with any
// particular store, so they're always considered as "yes I came
// from that store",
Val::I32(_) | Val::I64(_) | Val::F32(_) | Val::F64(_) | Val::V128(_) => true,
}
}
}
impl From<i32> for Val {
#[inline]
fn from(val: i32) -> Val {
Val::I32(val)
}
}
impl From<i64> for Val {
#[inline]
fn from(val: i64) -> Val {
Val::I64(val)
}
}
impl From<f32> for Val {
#[inline]
fn from(val: f32) -> Val {
Val::F32(val.to_bits())
}
}
impl From<f64> for Val {
#[inline]
fn from(val: f64) -> Val {
Val::F64(val.to_bits())
}
}
impl From<Ref> for Val {
#[inline]
fn from(val: Ref) -> Val {
match val {
Ref::Extern(e) => Val::ExternRef(e),
Ref::Func(f) => Val::FuncRef(f),
Ref::Any(a) => Val::AnyRef(a),
}
}
}
impl From<Rooted<ExternRef>> for Val {
#[inline]
fn from(val: Rooted<ExternRef>) -> Val {
Val::ExternRef(Some(val))
}
}
impl From<Option<Rooted<ExternRef>>> for Val {
#[inline]
fn from(val: Option<Rooted<ExternRef>>) -> Val {
Val::ExternRef(val)
}
}
impl From<Rooted<AnyRef>> for Val {
#[inline]
fn from(val: Rooted<AnyRef>) -> Val {
Val::AnyRef(Some(val))
}
}
impl From<Option<Rooted<AnyRef>>> for Val {
#[inline]
fn from(val: Option<Rooted<AnyRef>>) -> Val {
Val::AnyRef(val)
}
}
impl From<Rooted<StructRef>> for Val {
#[inline]
fn from(val: Rooted<StructRef>) -> Val {
Val::AnyRef(Some(val.into()))
}
}
impl From<Option<Rooted<StructRef>>> for Val {
#[inline]
fn from(val: Option<Rooted<StructRef>>) -> Val {
Val::AnyRef(val.map(Into::into))
}
}
impl From<Rooted<ArrayRef>> for Val {
#[inline]
fn from(val: Rooted<ArrayRef>) -> Val {
Val::AnyRef(Some(val.into()))
}
}
impl From<Option<Rooted<ArrayRef>>> for Val {
#[inline]
fn from(val: Option<Rooted<ArrayRef>>) -> Val {
Val::AnyRef(val.map(Into::into))
}
}
impl From<Func> for Val {
#[inline]
fn from(val: Func) -> Val {
Val::FuncRef(Some(val))
}
}
impl From<Option<Func>> for Val {
#[inline]
fn from(val: Option<Func>) -> Val {
Val::FuncRef(val)
}
}
impl From<u128> for Val {
#[inline]
fn from(val: u128) -> Val {
Val::V128(val.into())
}
}
impl From<V128> for Val {
#[inline]
fn from(val: V128) -> Val {
Val::V128(val)
}
}
/// A reference.
///
/// References come in three broad flavors:
///
/// 1. Function references. These are references to a function that can be
/// invoked.
///
/// 2. External references. These are references to data that is external
/// and opaque to the Wasm guest, provided by the host.
///
/// 3. Internal references. These are references to allocations inside the
/// Wasm's heap, such as structs and arrays. These are part of the GC
/// proposal, and not yet implemented in Wasmtime.
///
/// At the Wasm level, there are nullable and non-nullable variants of each type
/// of reference. Both variants are represented with `Ref` at the Wasmtime API
/// level. For example, values of both `(ref extern)` and `(ref null extern)`
/// types will be represented as `Ref::Extern(Option<ExternRef>)` in the
/// Wasmtime API. Nullable references are represented as `Option<Ref>` where
/// null references are represented as `None`. Wasm can construct null
/// references via the `ref.null <heap-type>` instruction.
///
/// References are non-forgable: Wasm cannot create invalid references, for
/// example, by claiming that the integer `0xbad1bad2` is actually a reference.
#[derive(Debug, Clone)]
pub enum Ref {
// NB: We have a variant for each of the type hierarchies defined in Wasm,
// and push the `Option` that provides nullability into each variant. This
// allows us to get the most-precise type of any reference value, whether it
// is null or not, without any additional metadata.
//
// Consider if we instead had the nullability inside `Val::Ref` and each of
// the `Ref` variants did not have an `Option`:
//
// enum Val {
// Ref(Option<Ref>),
// // Etc...
// }
// enum Ref {
// Func(Func),
// External(ExternRef),
// // Etc...
// }
//
// In this scenario, what type would we return from `Val::ty` for
// `Val::Ref(None)`? Because Wasm has multiple separate type hierarchies,
// there is no single common bottom type for all the different kinds of
// references. So in this scenario, `Val::Ref(None)` doesn't have enough
// information to reconstruct the value's type. That's a problem for us
// because we need to get a value's type at various times all over the code
// base.
//
/// A first-class reference to a WebAssembly function.
///
/// The host, or the Wasm guest, can invoke this function.
///
/// The host can create function references via [`Func::new`] or
/// [`Func::wrap`].
///
/// The Wasm guest can create non-null function references via the
/// `ref.func` instruction, or null references via the `ref.null func`
/// instruction.
Func(Option<Func>),
/// A reference to an value outside of the Wasm heap.
///
/// These references are opaque to the Wasm itself. Wasm can't create
/// non-null external references, nor do anything with them accept pass them
/// around as function arguments and returns and place them into globals and
/// tables.
///
/// Wasm can create null external references via the `ref.null extern`
/// instruction.
Extern(Option<Rooted<ExternRef>>),
/// An internal reference.
///
/// The `AnyRef` type represents WebAssembly `anyref` values. These can be
/// references to `struct`s and `array`s or inline/unboxed 31-bit
/// integers.
///
/// Unlike `externref`, Wasm guests can directly allocate `anyref`s, and
/// does not need to rely on the host to do that.
Any(Option<Rooted<AnyRef>>),
}
impl From<Func> for Ref {
#[inline]
fn from(f: Func) -> Ref {
Ref::Func(Some(f))
}
}
impl From<Option<Func>> for Ref {
#[inline]
fn from(f: Option<Func>) -> Ref {
Ref::Func(f)
}
}
impl From<Rooted<ExternRef>> for Ref {
#[inline]
fn from(e: Rooted<ExternRef>) -> Ref {
Ref::Extern(Some(e))
}
}
impl From<Option<Rooted<ExternRef>>> for Ref {
#[inline]
fn from(e: Option<Rooted<ExternRef>>) -> Ref {
Ref::Extern(e)
}
}
impl From<Rooted<AnyRef>> for Ref {
#[inline]
fn from(e: Rooted<AnyRef>) -> Ref {
Ref::Any(Some(e))
}
}
impl From<Option<Rooted<AnyRef>>> for Ref {
#[inline]
fn from(e: Option<Rooted<AnyRef>>) -> Ref {
Ref::Any(e)
}
}
impl From<Rooted<StructRef>> for Ref {
#[inline]
fn from(e: Rooted<StructRef>) -> Ref {
Ref::Any(Some(e.into()))
}
}
impl From<Option<Rooted<StructRef>>> for Ref {
#[inline]
fn from(e: Option<Rooted<StructRef>>) -> Ref {
Ref::Any(e.map(Into::into))
}
}
impl From<Rooted<ArrayRef>> for Ref {
#[inline]
fn from(e: Rooted<ArrayRef>) -> Ref {
Ref::Any(Some(e.into()))
}
}
impl From<Option<Rooted<ArrayRef>>> for Ref {
#[inline]
fn from(e: Option<Rooted<ArrayRef>>) -> Ref {
Ref::Any(e.map(Into::into))
}
}
impl Ref {
/// Create a null reference to the given heap type.
#[inline]
pub fn null(heap_type: &HeapType) -> Self {
match heap_type.top() {
HeapType::Any => Ref::Any(None),
HeapType::Extern => Ref::Extern(None),
HeapType::Func => Ref::Func(None),
ty => unreachable!("not a heap type: {ty:?}"),
}
}
/// Is this a null reference?
#[inline]
pub fn is_null(&self) -> bool {
match self {
Ref::Any(None) | Ref::Extern(None) | Ref::Func(None) => true,
Ref::Any(Some(_)) | Ref::Extern(Some(_)) | Ref::Func(Some(_)) => false,
}
}
/// Is this a non-null reference?
#[inline]
pub fn is_non_null(&self) -> bool {
!self.is_null()
}
/// Is this an `extern` reference?
#[inline]
pub fn is_extern(&self) -> bool {
matches!(self, Ref::Extern(_))
}
/// Get the underlying `extern` reference, if any.
///
/// Returns `None` if this `Ref` is not an `extern` reference, eg it is a
/// `func` reference.
///
/// Returns `Some(None)` if this `Ref` is a null `extern` reference.
///
/// Returns `Some(Some(_))` if this `Ref` is a non-null `extern` reference.
#[inline]
pub fn as_extern(&self) -> Option<Option<&Rooted<ExternRef>>> {
match self {
Ref::Extern(e) => Some(e.as_ref()),
_ => None,
}
}
/// Get the underlying `extern` reference, panicking if this is a different
/// kind of reference.
///
/// Returns `None` if this `Ref` is a null `extern` reference.
///
/// Returns `Some(_)` if this `Ref` is a non-null `extern` reference.
#[inline]
pub fn unwrap_extern(&self) -> Option<&Rooted<ExternRef>> {
self.as_extern()
.expect("Ref::unwrap_extern on non-extern reference")
}
/// Is this an `any` reference?
#[inline]
pub fn is_any(&self) -> bool {
matches!(self, Ref::Any(_))
}
/// Get the underlying `any` reference, if any.
///
/// Returns `None` if this `Ref` is not an `any` reference, eg it is a
/// `func` reference.
///
/// Returns `Some(None)` if this `Ref` is a null `any` reference.
///
/// Returns `Some(Some(_))` if this `Ref` is a non-null `any` reference.
#[inline]
pub fn as_any(&self) -> Option<Option<&Rooted<AnyRef>>> {
match self {
Ref::Any(e) => Some(e.as_ref()),
_ => None,
}
}
/// Get the underlying `any` reference, panicking if this is a different
/// kind of reference.
///
/// Returns `None` if this `Ref` is a null `any` reference.
///
/// Returns `Some(_)` if this `Ref` is a non-null `any` reference.
#[inline]
pub fn unwrap_any(&self) -> Option<&Rooted<AnyRef>> {
self.as_any().expect("Ref::unwrap_any on non-any reference")
}
/// Is this a `func` reference?
#[inline]
pub fn is_func(&self) -> bool {
matches!(self, Ref::Func(_))
}
/// Get the underlying `func` reference, if any.
///
/// Returns `None` if this `Ref` is not an `func` reference, eg it is an
/// `extern` reference.
///
/// Returns `Some(None)` if this `Ref` is a null `func` reference.
///
/// Returns `Some(Some(_))` if this `Ref` is a non-null `func` reference.
#[inline]
pub fn as_func(&self) -> Option<Option<&Func>> {
match self {
Ref::Func(f) => Some(f.as_ref()),
_ => None,
}
}
/// Get the underlying `func` reference, panicking if this is a different
/// kind of reference.
///
/// Returns `None` if this `Ref` is a null `func` reference.
///
/// Returns `Some(_)` if this `Ref` is a non-null `func` reference.
#[inline]
pub fn unwrap_func(&self) -> Option<&Func> {
self.as_func()
.expect("Ref::unwrap_func on non-func reference")
}
/// Get the type of this reference.
///
/// # Errors
///
/// Return an error if this reference has been unrooted.
///
/// # Panics
///
/// Panics if this reference is associated with a different store.
pub fn ty(&self, store: impl AsContext) -> Result<RefType> {
self.load_ty(&store.as_context().0)
}
pub(crate) fn load_ty(&self, store: &StoreOpaque) -> Result<RefType> {
assert!(self.comes_from_same_store(store));
Ok(RefType::new(
self.is_null(),
// NB: We choose the most-specific heap type we can here and let
// subtyping do its thing if callers are matching against a
// `HeapType::Func`.
match self {
Ref::Extern(None) => HeapType::NoExtern,
Ref::Extern(Some(_)) => HeapType::Extern,
Ref::Func(None) => HeapType::NoFunc,
Ref::Func(Some(f)) => HeapType::ConcreteFunc(f.load_ty(store)),
Ref::Any(None) => HeapType::None,
Ref::Any(Some(a)) => a._ty(store)?,
},
))
}
/// Does this reference value match the given type?
///
/// Returns an error if the underlying `Rooted` has been unrooted.
///
/// # Panics
///
/// Panics if this reference is not associated with the given store.
pub fn matches_ty(&self, store: impl AsContext, ty: &RefType) -> Result<bool> {
self._matches_ty(&store.as_context().0, ty)
}
pub(crate) fn _matches_ty(&self, store: &StoreOpaque, ty: &RefType) -> Result<bool> {
assert!(self.comes_from_same_store(store));
assert!(ty.comes_from_same_engine(store.engine()));
if self.is_null() && !ty.is_nullable() {
return Ok(false);
}
Ok(match (self, ty.heap_type()) {
(Ref::Extern(_), HeapType::Extern) => true,
(Ref::Extern(_), _) => false,
(Ref::Func(_), HeapType::Func) => true,
(Ref::Func(None), HeapType::NoFunc | HeapType::ConcreteFunc(_)) => true,
(Ref::Func(Some(f)), HeapType::ConcreteFunc(func_ty)) => f._matches_ty(store, func_ty),
(Ref::Func(_), _) => false,
(Ref::Any(_), HeapType::Any) => true,
(Ref::Any(Some(a)), HeapType::I31) => a._is_i31(store)?,
(Ref::Any(Some(a)), HeapType::Struct) => a._is_struct(store)?,
(Ref::Any(Some(a)), HeapType::ConcreteStruct(_ty)) => match a._as_struct(store)? {
None => false,
#[cfg_attr(not(feature = "gc"), allow(unreachable_patterns))]
Some(s) => s._matches_ty(store, _ty)?,
},
(Ref::Any(Some(_)), HeapType::Eq) => todo!("eqref"),
(Ref::Any(Some(a)), HeapType::Array) => a._is_array(store)?,
(Ref::Any(Some(a)), HeapType::ConcreteArray(_ty)) => match a._as_array(store)? {
None => false,
#[cfg_attr(not(feature = "gc"), allow(unreachable_patterns))]
Some(a) => a._matches_ty(store, _ty)?,
},
(
Ref::Any(None),
HeapType::None
| HeapType::I31
| HeapType::ConcreteStruct(_)
| HeapType::Struct
| HeapType::ConcreteArray(_)
| HeapType::Array,
) => true,
(Ref::Any(_), _) => false,
})
}
pub(crate) fn ensure_matches_ty(&self, store: &StoreOpaque, ty: &RefType) -> Result<()> {
if !self.comes_from_same_store(store) {
bail!("reference used with wrong store")
}
if !ty.comes_from_same_engine(store.engine()) {
bail!("type used with wrong engine")
}
if self._matches_ty(store, ty)? {
Ok(())
} else {
let actual_ty = self.load_ty(store)?;
bail!("type mismatch: expected {ty}, found {actual_ty}")
}
}
pub(crate) fn comes_from_same_store(&self, store: &StoreOpaque) -> bool {
match self {
Ref::Func(Some(f)) => f.comes_from_same_store(store),
Ref::Func(None) => true,
Ref::Extern(Some(x)) => x.comes_from_same_store(store),
Ref::Extern(None) => true,
Ref::Any(Some(a)) => a.comes_from_same_store(store),
Ref::Any(None) => true,
}
}
pub(crate) fn into_table_element(
self,
store: &mut StoreOpaque,
ty: &RefType,
) -> Result<TableElement> {
let mut store = AutoAssertNoGc::new(store);
self.ensure_matches_ty(&store, &ty)
.context("type mismatch: value does not match table element type")?;
match (self, ty.heap_type().top()) {
(Ref::Func(None), HeapType::Func) => {
assert!(ty.is_nullable());
Ok(TableElement::FuncRef(ptr::null_mut()))
}
(Ref::Func(Some(f)), HeapType::Func) => {
debug_assert!(
f.comes_from_same_store(&store),
"checked in `ensure_matches_ty`"
);
Ok(TableElement::FuncRef(f.vm_func_ref(&mut store).as_ptr()))
}
(Ref::Extern(e), HeapType::Extern) => match e {
None => {
assert!(ty.is_nullable());
Ok(TableElement::GcRef(None))
}
#[cfg_attr(not(feature = "gc"), allow(unreachable_patterns))]
Some(e) => {
let gc_ref = e.try_clone_gc_ref(&mut store)?;
Ok(TableElement::GcRef(Some(gc_ref)))
}
},
(Ref::Any(a), HeapType::Any) => match a {
None => {
assert!(ty.is_nullable());
Ok(TableElement::GcRef(None))
}
#[cfg_attr(not(feature = "gc"), allow(unreachable_patterns))]
Some(a) => {
let gc_ref = a.try_clone_gc_ref(&mut store)?;
Ok(TableElement::GcRef(Some(gc_ref)))
}
},
_ => unreachable!("checked that the value matches the type above"),
}
}
}
#[cfg(test)]
mod tests {
use crate::*;
#[test]
fn size_of_val() {
// Try to keep tabs on the size of `Val` and make sure we don't grow its
// size.
assert_eq!(
std::mem::size_of::<Val>(),
if cfg!(any(
target_arch = "x86_64",
target_arch = "aarch64",
target_arch = "riscv64",
target_arch = "s390x"
)) {
24
} else {
panic!("unsupported architecture")
}
);
}
#[test]
fn size_of_ref() {
// Try to keep tabs on the size of `Ref` and make sure we don't grow its
// size.
assert_eq!(std::mem::size_of::<Ref>(), 24);
}
#[test]
#[should_panic]
fn val_matches_ty_wrong_engine() {
let e1 = Engine::default();
let e2 = Engine::default();
let t1 = FuncType::new(&e1, None, None);
let t2 = FuncType::new(&e2, None, None);
let mut s1 = Store::new(&e1, ());
let f = Func::new(&mut s1, t1.clone(), |_caller, _args, _results| Ok(()));
// Should panic.
let _ = Val::FuncRef(Some(f)).matches_ty(
&s1,
&ValType::Ref(RefType::new(true, HeapType::ConcreteFunc(t2))),
);
}
#[test]
#[should_panic]
fn ref_matches_ty_wrong_engine() {
let e1 = Engine::default();
let e2 = Engine::default();
let t1 = FuncType::new(&e1, None, None);
let t2 = FuncType::new(&e2, None, None);
let mut s1 = Store::new(&e1, ());
let f = Func::new(&mut s1, t1.clone(), |_caller, _args, _results| Ok(()));
// Should panic.
let _ = Ref::Func(Some(f)).matches_ty(&s1, &RefType::new(true, HeapType::ConcreteFunc(t2)));
}
}