1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484
use crate::prelude::*;
use crate::runtime::vm::{self as runtime};
use crate::store::{AutoAssertNoGc, StoreData, StoreOpaque, Stored};
use crate::trampoline::generate_table_export;
use crate::{AnyRef, AsContext, AsContextMut, ExternRef, Func, HeapType, Ref, TableType};
use core::iter;
use core::ptr::NonNull;
use runtime::{GcRootsList, SendSyncPtr};
use wasmtime_environ::TypeTrace;
/// A WebAssembly `table`, or an array of values.
///
/// Like [`Memory`][crate::Memory] a table is an indexed array of values, but
/// unlike [`Memory`][crate::Memory] it's an array of WebAssembly reference type
/// values rather than bytes. One of the most common usages of a table is a
/// function table for wasm modules (a `funcref` table), where each element has
/// the `ValType::FuncRef` type.
///
/// A [`Table`] "belongs" to the store that it was originally created within
/// (either via [`Table::new`] or via instantiating a
/// [`Module`](crate::Module)). Operations on a [`Table`] only work with the
/// store it belongs to, and if another store is passed in by accident then
/// methods will panic.
#[derive(Copy, Clone, Debug)]
#[repr(transparent)] // here for the C API
pub struct Table(pub(super) Stored<crate::runtime::vm::ExportTable>);
impl Table {
/// Creates a new [`Table`] with the given parameters.
///
/// * `store` - the owner of the resulting [`Table`]
/// * `ty` - the type of this table, containing both the element type as
/// well as the initial size and maximum size, if any.
/// * `init` - the initial value to fill all table entries with, if the
/// table starts with an initial size.
///
/// # Errors
///
/// Returns an error if `init` does not match the element type of the table,
/// or if `init` does not belong to the `store` provided.
///
/// # Panics
///
/// This function will panic when used with a [`Store`](`crate::Store`)
/// which has a [`ResourceLimiterAsync`](`crate::ResourceLimiterAsync`)
/// (see also: [`Store::limiter_async`](`crate::Store::limiter_async`).
/// When using an async resource limiter, use [`Table::new_async`]
/// instead.
///
/// # Examples
///
/// ```
/// # use wasmtime::*;
/// # fn main() -> anyhow::Result<()> {
/// let engine = Engine::default();
/// let mut store = Store::new(&engine, ());
///
/// let ty = TableType::new(RefType::FUNCREF, 2, None);
/// let table = Table::new(&mut store, ty, Ref::Func(None))?;
///
/// let module = Module::new(
/// &engine,
/// "(module
/// (table (import \"\" \"\") 2 funcref)
/// (func $f (result i32)
/// i32.const 10)
/// (elem (i32.const 0) $f)
/// )"
/// )?;
///
/// let instance = Instance::new(&mut store, &module, &[table.into()])?;
/// // ...
/// # Ok(())
/// # }
/// ```
pub fn new(mut store: impl AsContextMut, ty: TableType, init: Ref) -> Result<Table> {
Table::_new(store.as_context_mut().0, ty, init)
}
/// Async variant of [`Table::new`]. You must use this variant with
/// [`Store`](`crate::Store`)s which have a
/// [`ResourceLimiterAsync`](`crate::ResourceLimiterAsync`).
///
/// # Panics
///
/// This function will panic when used with a non-async
/// [`Store`](`crate::Store`)
#[cfg(feature = "async")]
pub async fn new_async<T>(
mut store: impl AsContextMut<Data = T>,
ty: TableType,
init: Ref,
) -> Result<Table>
where
T: Send,
{
let mut store = store.as_context_mut();
assert!(
store.0.async_support(),
"cannot use `new_async` without enabling async support on the config"
);
store
.on_fiber(|store| Table::_new(store.0, ty, init))
.await?
}
fn _new(store: &mut StoreOpaque, ty: TableType, init: Ref) -> Result<Table> {
let wasmtime_export = generate_table_export(store, &ty)?;
let init = init.into_table_element(store, ty.element())?;
unsafe {
let table = Table::from_wasmtime_table(wasmtime_export, store);
let wasmtime_table = table.wasmtime_table(store, iter::empty());
(*wasmtime_table)
.fill(store.gc_store_mut()?, 0, init, ty.minimum())
.err2anyhow()?;
Ok(table)
}
}
/// Returns the underlying type of this table, including its element type as
/// well as the maximum/minimum lower bounds.
///
/// # Panics
///
/// Panics if `store` does not own this table.
pub fn ty(&self, store: impl AsContext) -> TableType {
self._ty(store.as_context().0)
}
fn _ty(&self, store: &StoreOpaque) -> TableType {
let ty = &store[self.0].table.table;
TableType::from_wasmtime_table(store.engine(), ty)
}
fn wasmtime_table(
&self,
store: &mut StoreOpaque,
lazy_init_range: impl Iterator<Item = u64>,
) -> *mut runtime::Table {
unsafe {
let export = &store[self.0];
crate::runtime::vm::Instance::from_vmctx(export.vmctx, |handle| {
let idx = handle.table_index(&*export.definition);
handle.get_defined_table_with_lazy_init(idx, lazy_init_range)
})
}
}
/// Returns the table element value at `index`.
///
/// Returns `None` if `index` is out of bounds.
///
/// # Panics
///
/// Panics if `store` does not own this table.
pub fn get(&self, mut store: impl AsContextMut, index: u64) -> Option<Ref> {
let mut store = AutoAssertNoGc::new(store.as_context_mut().0);
let table = self.wasmtime_table(&mut store, iter::once(index));
unsafe {
match (*table).get(store.unwrap_gc_store_mut(), index)? {
runtime::TableElement::FuncRef(f) => {
let func = Func::from_vm_func_ref(&mut store, f);
Some(func.into())
}
runtime::TableElement::UninitFunc => {
unreachable!("lazy init above should have converted UninitFunc")
}
runtime::TableElement::GcRef(None) => {
Some(Ref::null(self._ty(&store).element().heap_type()))
}
#[cfg_attr(not(feature = "gc"), allow(unreachable_code, unused_variables))]
runtime::TableElement::GcRef(Some(x)) => {
match self._ty(&store).element().heap_type().top() {
HeapType::Any => {
let x = AnyRef::from_cloned_gc_ref(&mut store, x);
Some(x.into())
}
HeapType::Extern => {
let x = ExternRef::from_cloned_gc_ref(&mut store, x);
Some(x.into())
}
HeapType::Func => {
unreachable!("never have TableElement::GcRef for func tables")
}
ty => unreachable!("not a top type: {ty:?}"),
}
}
}
}
}
/// Writes the `val` provided into `index` within this table.
///
/// # Errors
///
/// Returns an error if `index` is out of bounds, if `val` does not have
/// the right type to be stored in this table, or if `val` belongs to a
/// different store.
///
/// # Panics
///
/// Panics if `store` does not own this table.
pub fn set(&self, mut store: impl AsContextMut, index: u64, val: Ref) -> Result<()> {
let store = store.as_context_mut().0;
let ty = self.ty(&store);
let val = val.into_table_element(store, ty.element())?;
let table = self.wasmtime_table(store, iter::empty());
unsafe {
(*table)
.set(index, val)
.map_err(|()| anyhow!("table element index out of bounds"))
}
}
/// Returns the current size of this table.
///
/// # Panics
///
/// Panics if `store` does not own this table.
pub fn size(&self, store: impl AsContext) -> u64 {
self.internal_size(store.as_context().0)
}
pub(crate) fn internal_size(&self, store: &StoreOpaque) -> u64 {
// unwrap here should be ok because the runtime should always guarantee
// that we can fit the number of elements in a 64-bit integer.
unsafe { u64::try_from((*store[self.0].definition).current_elements).unwrap() }
}
/// Grows the size of this table by `delta` more elements, initialization
/// all new elements to `init`.
///
/// Returns the previous size of this table if successful.
///
/// # Errors
///
/// Returns an error if the table cannot be grown by `delta`, for example
/// if it would cause the table to exceed its maximum size. Also returns an
/// error if `init` is not of the right type or if `init` does not belong to
/// `store`.
///
/// # Panics
///
/// Panics if `store` does not own this table.
///
/// This function will panic when used with a [`Store`](`crate::Store`)
/// which has a [`ResourceLimiterAsync`](`crate::ResourceLimiterAsync`)
/// (see also: [`Store::limiter_async`](`crate::Store::limiter_async`)).
/// When using an async resource limiter, use [`Table::grow_async`]
/// instead.
pub fn grow(&self, mut store: impl AsContextMut, delta: u64, init: Ref) -> Result<u64> {
let store = store.as_context_mut().0;
let ty = self.ty(&store);
let init = init.into_table_element(store, ty.element())?;
let table = self.wasmtime_table(store, iter::empty());
unsafe {
match (*table).grow(delta, init, store)? {
Some(size) => {
let vm = (*table).vmtable();
*store[self.0].definition = vm;
// unwrap here should be ok because the runtime should always guarantee
// that we can fit the table size in a 64-bit integer.
Ok(u64::try_from(size).unwrap())
}
None => bail!("failed to grow table by `{}`", delta),
}
}
}
/// Async variant of [`Table::grow`]. Required when using a
/// [`ResourceLimiterAsync`](`crate::ResourceLimiterAsync`).
///
/// # Panics
///
/// This function will panic when used with a non-async
/// [`Store`](`crate::Store`).
#[cfg(feature = "async")]
pub async fn grow_async<T>(
&self,
mut store: impl AsContextMut<Data = T>,
delta: u64,
init: Ref,
) -> Result<u64>
where
T: Send,
{
let mut store = store.as_context_mut();
assert!(
store.0.async_support(),
"cannot use `grow_async` without enabling async support on the config"
);
store
.on_fiber(|store| self.grow(store, delta, init))
.await?
}
/// Copy `len` elements from `src_table[src_index..]` into
/// `dst_table[dst_index..]`.
///
/// # Errors
///
/// Returns an error if the range is out of bounds of either the source or
/// destination tables, or if the source table's element type does not match
/// the destination table's element type.
///
/// # Panics
///
/// Panics if `store` does not own either `dst_table` or `src_table`.
pub fn copy(
mut store: impl AsContextMut,
dst_table: &Table,
dst_index: u64,
src_table: &Table,
src_index: u64,
len: u64,
) -> Result<()> {
let store = store.as_context_mut().0;
let dst_ty = dst_table.ty(&store);
let src_ty = src_table.ty(&store);
src_ty
.element()
.ensure_matches(store.engine(), dst_ty.element())
.context(
"type mismatch: source table's element type does not match \
destination table's element type",
)?;
let dst_table = dst_table.wasmtime_table(store, iter::empty());
let src_range = src_index..(src_index.checked_add(len).unwrap_or(u64::MAX));
let src_table = src_table.wasmtime_table(store, src_range);
unsafe {
runtime::Table::copy(
store.gc_store_mut()?,
dst_table,
src_table,
dst_index,
src_index,
len,
)
.err2anyhow()?;
}
Ok(())
}
/// Fill `table[dst..(dst + len)]` with the given value.
///
/// # Errors
///
/// Returns an error if
///
/// * `val` is not of the same type as this table's
/// element type,
///
/// * the region to be filled is out of bounds, or
///
/// * `val` comes from a different `Store` from this table.
///
/// # Panics
///
/// Panics if `store` does not own either `dst_table` or `src_table`.
pub fn fill(&self, mut store: impl AsContextMut, dst: u64, val: Ref, len: u64) -> Result<()> {
let store = store.as_context_mut().0;
let ty = self.ty(&store);
let val = val.into_table_element(store, ty.element())?;
let table = self.wasmtime_table(store, iter::empty());
unsafe {
(*table)
.fill(store.gc_store_mut()?, dst, val, len)
.err2anyhow()?;
}
Ok(())
}
pub(crate) fn trace_roots(&self, store: &mut StoreOpaque, gc_roots_list: &mut GcRootsList) {
if !self
._ty(store)
.element()
.is_vmgcref_type_and_points_to_object()
{
return;
}
let table = self.wasmtime_table(store, iter::empty());
for gc_ref in unsafe { (*table).gc_refs_mut() } {
if let Some(gc_ref) = gc_ref {
let gc_ref = NonNull::from(gc_ref);
let gc_ref = SendSyncPtr::new(gc_ref);
unsafe {
gc_roots_list.add_root(gc_ref, "Wasm table element");
}
}
}
}
pub(crate) unsafe fn from_wasmtime_table(
mut wasmtime_export: crate::runtime::vm::ExportTable,
store: &mut StoreOpaque,
) -> Table {
// Ensure that the table's type is engine-level canonicalized.
wasmtime_export
.table
.table
.ref_type
.canonicalize_for_runtime_usage(&mut |module_index| {
crate::runtime::vm::Instance::from_vmctx(wasmtime_export.vmctx, |instance| {
instance.engine_type_index(module_index)
})
});
Table(store.store_data_mut().insert(wasmtime_export))
}
pub(crate) fn wasmtime_ty<'a>(&self, data: &'a StoreData) -> &'a wasmtime_environ::Table {
&data[self.0].table.table
}
pub(crate) fn vmimport(&self, store: &StoreOpaque) -> crate::runtime::vm::VMTableImport {
let export = &store[self.0];
crate::runtime::vm::VMTableImport {
from: export.definition,
vmctx: export.vmctx,
}
}
/// Get a stable hash key for this table.
///
/// Even if the same underlying table definition is added to the
/// `StoreData` multiple times and becomes multiple `wasmtime::Table`s,
/// this hash key will be consistent across all of these tables.
#[allow(dead_code)] // Not used yet, but added for consistency.
pub(crate) fn hash_key(&self, store: &StoreOpaque) -> impl core::hash::Hash + Eq {
store[self.0].definition as usize
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::{Instance, Module, Store};
#[test]
fn hash_key_is_stable_across_duplicate_store_data_entries() -> Result<()> {
let mut store = Store::<()>::default();
let module = Module::new(
store.engine(),
r#"
(module
(table (export "t") 1 1 externref)
)
"#,
)?;
let instance = Instance::new(&mut store, &module, &[])?;
// Each time we `get_table`, we call `Table::from_wasmtime` which adds
// a new entry to `StoreData`, so `t1` and `t2` will have different
// indices into `StoreData`.
let t1 = instance.get_table(&mut store, "t").unwrap();
let t2 = instance.get_table(&mut store, "t").unwrap();
// That said, they really point to the same table.
assert!(t1.get(&mut store, 0).unwrap().unwrap_extern().is_none());
assert!(t2.get(&mut store, 0).unwrap().unwrap_extern().is_none());
let e = ExternRef::new(&mut store, 42)?;
t1.set(&mut store, 0, e.into())?;
assert!(t1.get(&mut store, 0).unwrap().unwrap_extern().is_some());
assert!(t2.get(&mut store, 0).unwrap().unwrap_extern().is_some());
// And therefore their hash keys are the same.
assert!(t1.hash_key(&store.as_context().0) == t2.hash_key(&store.as_context().0));
// But the hash keys are different from different tables.
let instance2 = Instance::new(&mut store, &module, &[])?;
let t3 = instance2.get_table(&mut store, "t").unwrap();
assert!(t1.hash_key(&store.as_context().0) != t3.hash_key(&store.as_context().0));
Ok(())
}
}