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Add a first-class way of accessing caller's exports (#1290)

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* Add a first-class way of accessing caller's exports

This commit is a continuation of #1237 and updates the API of `Func` to
allow defining host functions which have easy access to a caller's
memory in particular. The new APIs look like so:

* The `Func::wrap*` family of functions was condensed into one
  `Func::wrap` function.
* The ABI layer of conversions in `WasmTy` were removed
* An optional `Caller<'_>` argument can be at the front of all
  host-defined functions now.

The old way the wasi bindings looked up memory has been removed and is
now replaced with the `Caller` type. The `Caller` type has a
`get_export` method on it which allows looking up a caller's export by
name, allowing you to get access to the caller's memory easily, and even
during instantiation.

* Add a temporary note

* Move some docs
This commit is contained in:
Alex Crichton
2020-03-18 16:57:31 -05:00
committed by GitHub
parent 1958e8af96
commit f63c3c814e
10 changed files with 550 additions and 509 deletions
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577
crates/api/src/func.rs
View File

@@ -1,12 +1,12 @@
use crate::callable::{NativeCallable, WasmtimeFn, WrappedCallable}; use crate::callable::{NativeCallable, WasmtimeFn, WrappedCallable};
use crate::{Callable, FuncType, Store, Trap, Val, ValType}; use crate::{Callable, Extern, FuncType, Memory, Store, Trap, Val, ValType};
use anyhow::{ensure, Context as _}; use anyhow::{ensure, Context as _};
use std::fmt; use std::fmt;
use std::mem; use std::mem;
use std::panic::{self, AssertUnwindSafe}; use std::panic::{self, AssertUnwindSafe};
use std::ptr; use std::ptr;
use std::rc::Rc; use std::rc::Rc;
use wasmtime_runtime::{InstanceHandle, VMContext, VMFunctionBody}; use wasmtime_runtime::{Export, InstanceHandle, VMContext, VMFunctionBody};
/// A WebAssembly function which can be called. /// A WebAssembly function which can be called.
/// ///
@@ -59,7 +59,7 @@ use wasmtime_runtime::{InstanceHandle, VMContext, VMFunctionBody};
/// # } /// # }
/// ``` /// ```
/// ///
/// You can also use the [`wrap*` family of functions](Func::wrap1) to create a /// You can also use the [`wrap` function](Func::wrap) to create a
/// `Func` /// `Func`
/// ///
/// ``` /// ```
@@ -69,7 +69,7 @@ use wasmtime_runtime::{InstanceHandle, VMContext, VMFunctionBody};
/// ///
/// // Create a custom `Func` which can execute arbitrary code inside of the /// // Create a custom `Func` which can execute arbitrary code inside of the
/// // closure. /// // closure.
/// let add = Func::wrap2(&store, |a: i32, b: i32| -> i32 { a + b }); /// let add = Func::wrap(&store, |a: i32, b: i32| -> i32 { a + b });
/// ///
/// // Next we can hook that up to a wasm module which uses it. /// // Next we can hook that up to a wasm module which uses it.
/// let module = Module::new( /// let module = Module::new(
@@ -148,95 +148,6 @@ pub struct Func {
ty: FuncType, ty: FuncType,
} }
macro_rules! wrappers {
($(
$(#[$doc:meta])*
($name:ident $(,$args:ident)*)
)*) => ($(
$(#[$doc])*
pub fn $name<F, $($args,)* R>(store: &Store, func: F) -> Func
where
F: Fn($($args),*) -> R + 'static,
$($args: WasmTy,)*
R: WasmRet,
{
#[allow(non_snake_case)]
unsafe extern "C" fn shim<F, $($args,)* R>(
vmctx: *mut VMContext,
_caller_vmctx: *mut VMContext,
$($args: $args::Abi,)*
) -> R::Abi
where
F: Fn($($args),*) -> R + 'static,
$($args: WasmTy,)*
R: WasmRet,
{
let ret = {
let instance = InstanceHandle::from_vmctx(vmctx);
let func = instance.host_state().downcast_ref::<F>().expect("state");
panic::catch_unwind(AssertUnwindSafe(|| {
func($($args::from_abi(_caller_vmctx, $args)),*)
}))
};
match ret {
Ok(ret) => ret.into_abi(),
Err(panic) => wasmtime_runtime::resume_panic(panic),
}
}
#[allow(non_snake_case)]
unsafe extern "C" fn trampoline<F, $($args,)* R>(
callee_vmctx: *mut VMContext,
caller_vmctx: *mut VMContext,
ptr: *const VMFunctionBody,
args: *mut u128,
)
where
F: Fn($($args),*) -> R + 'static,
$($args: WasmTy,)*
R: WasmRet,
{
let ptr = mem::transmute::<
*const VMFunctionBody,
unsafe extern "C" fn(
*mut VMContext,
*mut VMContext,
$($args::Abi,)*
) -> R::Abi,
>(ptr);
let mut _next = args as *const u128;
$(let $args = $args::load(&mut _next);)*
let ret = ptr(callee_vmctx, caller_vmctx, $($args),*);
R::store(ret, args);
}
let mut _args = Vec::new();
$($args::push(&mut _args);)*
let mut ret = Vec::new();
R::push(&mut ret);
let ty = FuncType::new(_args.into(), ret.into());
unsafe {
let trampoline = trampoline::<F, $($args,)* R>;
let (instance, export) = crate::trampoline::generate_raw_func_export(
&ty,
std::slice::from_raw_parts_mut(
shim::<F, $($args,)* R> as *mut _,
0,
),
trampoline,
store,
Box::new(func),
)
.expect("failed to generate export");
let callable = Rc::new(WasmtimeFn::new(store, instance, export, trampoline));
Func::from_wrapped(store, ty, callable)
}
}
)*)
}
macro_rules! getters { macro_rules! getters {
($( ($(
$(#[$doc:meta])* $(#[$doc:meta])*
@@ -277,15 +188,15 @@ macro_rules! getters {
unsafe extern "C" fn( unsafe extern "C" fn(
*mut VMContext, *mut VMContext,
*mut VMContext, *mut VMContext,
$($args::Abi,)* $($args,)*
) -> R::Abi, ) -> R,
>(f.address); >(f.address);
let mut ret = None; let mut ret = None;
$(let $args = $args.into_abi();)* $(let $args = $args.into_abi();)*
wasmtime_runtime::catch_traps(f.vmctx, || { wasmtime_runtime::catch_traps(f.vmctx, || {
ret = Some(fnptr(f.vmctx, ptr::null_mut(), $($args,)*)); ret = Some(fnptr(f.vmctx, ptr::null_mut(), $($args,)*));
}).map_err(Trap::from_jit)?; }).map_err(Trap::from_jit)?;
Ok(R::from_abi(f.vmctx, ret.unwrap())) Ok(ret.unwrap())
} }
}) })
} }
@@ -313,15 +224,7 @@ impl Func {
Func::from_wrapped(store, ty, callable) Func::from_wrapped(store, ty, callable)
} }
wrappers! { /// Creates a new `Func` from the given Rust closure.
/// Creates a new `Func` from the given Rust closure, which takes 0
/// arguments.
///
/// For more information about this function, see [`Func::wrap1`].
(wrap0)
/// Creates a new `Func` from the given Rust closure, which takes 1
/// argument.
/// ///
/// This function will create a new `Func` which, when called, will /// This function will create a new `Func` which, when called, will
/// execute the given Rust closure. Unlike [`Func::new`] the target /// execute the given Rust closure. Unlike [`Func::new`] the target
@@ -345,11 +248,20 @@ impl Func {
/// | `()` | nothing | no return value | /// | `()` | nothing | no return value |
/// | `Result<T, Trap>` | `T` | function may trap | /// | `Result<T, Trap>` | `T` | function may trap |
/// ///
/// Note that when using this API (and the related `wrap*` family of /// At this time multi-value returns are not supported, and supporting this
/// functions), the intention is to create as thin of a layer as /// is the subject of [#1178].
/// possible for when WebAssembly calls the function provided. With ///
/// sufficient inlining and optimization the WebAssembly will call /// [#1178]: https://github.com/bytecodealliance/wasmtime/issues/1178
/// straight into `func` provided, with no extra fluff entailed. ///
/// Finally you can also optionally take [`Caller`] as the first argument of
/// your closure. If inserted then you're able to inspect the caller's
/// state, for example the [`Memory`] it has exported so you can read what
/// pointers point to.
///
/// Note that when using this API, the intention is to create as thin of a
/// layer as possible for when WebAssembly calls the function provided. With
/// sufficient inlining and optimization the WebAssembly will call straight
/// into `func` provided, with no extra fluff entailed.
/// ///
/// # Examples /// # Examples
/// ///
@@ -360,7 +272,7 @@ impl Func {
/// # use wasmtime::*; /// # use wasmtime::*;
/// # fn main() -> anyhow::Result<()> { /// # fn main() -> anyhow::Result<()> {
/// # let store = Store::default(); /// # let store = Store::default();
/// let add = Func::wrap2(&store, |a: i32, b: i32| a + b); /// let add = Func::wrap(&store, |a: i32, b: i32| a + b);
/// let module = Module::new( /// let module = Module::new(
/// &store, /// &store,
/// r#" /// r#"
@@ -386,7 +298,7 @@ impl Func {
/// # use wasmtime::*; /// # use wasmtime::*;
/// # fn main() -> anyhow::Result<()> { /// # fn main() -> anyhow::Result<()> {
/// # let store = Store::default(); /// # let store = Store::default();
/// let add = Func::wrap2(&store, |a: i32, b: i32| { /// let add = Func::wrap(&store, |a: i32, b: i32| {
/// match a.checked_add(b) { /// match a.checked_add(b) {
/// Some(i) => Ok(i), /// Some(i) => Ok(i),
/// None => Err(Trap::new("overflow")), /// None => Err(Trap::new("overflow")),
@@ -417,7 +329,7 @@ impl Func {
/// # use wasmtime::*; /// # use wasmtime::*;
/// # fn main() -> anyhow::Result<()> { /// # fn main() -> anyhow::Result<()> {
/// # let store = Store::default(); /// # let store = Store::default();
/// let debug = Func::wrap4(&store, |a: i32, b: f32, c: i64, d: f64| { /// let debug = Func::wrap(&store, |a: i32, b: f32, c: i64, d: f64| {
/// println!("a={}", a); /// println!("a={}", a);
/// println!("b={}", b); /// println!("b={}", b);
/// println!("c={}", c); /// println!("c={}", c);
@@ -442,91 +354,64 @@ impl Func {
/// # Ok(()) /// # Ok(())
/// # } /// # }
/// ``` /// ```
(wrap1, A1)
/// Creates a new `Func` from the given Rust closure, which takes 2
/// arguments.
/// ///
/// For more information about this function, see [`Func::wrap1`]. /// Finally if you want to get really fancy you can also implement
(wrap2, A1, A2) /// imports that read/write wasm module's memory
/// Creates a new `Func` from the given Rust closure, which takes 3
/// arguments.
/// ///
/// For more information about this function, see [`Func::wrap1`]. /// ```
(wrap3, A1, A2, A3) /// use std::str;
/// Creates a new `Func` from the given Rust closure, which takes 4
/// arguments.
/// ///
/// For more information about this function, see [`Func::wrap1`]. /// # use wasmtime::*;
(wrap4, A1, A2, A3, A4) /// # fn main() -> anyhow::Result<()> {
/// # let store = Store::default();
/// Creates a new `Func` from the given Rust closure, which takes 5 /// let log_str = Func::wrap(&store, |caller: Caller<'_>, ptr: i32, len: i32| {
/// arguments. /// let mem = match caller.get_export("memory") {
/// Some(Extern::Memory(mem)) => mem,
/// _ => return Err(Trap::new("failed to find host memory")),
/// };
/// ///
/// For more information about this function, see [`Func::wrap1`]. /// // We're reading raw wasm memory here so we need `unsafe`. Note
(wrap5, A1, A2, A3, A4, A5) /// // though that this should be safe because we don't reenter wasm
/// // while we're reading wasm memory, nor should we clash with
/// Creates a new `Func` from the given Rust closure, which takes 6 /// // any other memory accessors (assuming they're well-behaved
/// arguments. /// // too).
/// /// unsafe {
/// For more information about this function, see [`Func::wrap1`]. /// let data = mem.data_unchecked()
(wrap6, A1, A2, A3, A4, A5, A6) /// .get(ptr as u32 as usize..)
/// .and_then(|arr| arr.get(..len as u32 as usize));
/// Creates a new `Func` from the given Rust closure, which takes 7 /// let string = match data {
/// arguments. /// Some(data) => match str::from_utf8(data) {
/// /// Ok(s) => s,
/// For more information about this function, see [`Func::wrap1`]. /// Err(_) => return Err(Trap::new("invalid utf-8")),
(wrap7, A1, A2, A3, A4, A5, A6, A7) /// },
/// None => return Err(Trap::new("pointer/length out of bounds")),
/// Creates a new `Func` from the given Rust closure, which takes 8 /// };
/// arguments. /// assert_eq!(string, "Hello, world!");
/// /// println!("{}", string);
/// For more information about this function, see [`Func::wrap1`]. /// }
(wrap8, A1, A2, A3, A4, A5, A6, A7, A8) /// Ok(())
/// });
/// Creates a new `Func` from the given Rust closure, which takes 9 /// let module = Module::new(
/// arguments. /// &store,
/// /// r#"
/// For more information about this function, see [`Func::wrap1`]. /// (module
(wrap9, A1, A2, A3, A4, A5, A6, A7, A8, A9) /// (import "" "" (func $log_str (param i32 i32)))
/// (func (export "foo")
/// Creates a new `Func` from the given Rust closure, which takes 10 /// i32.const 4 ;; ptr
/// arguments. /// i32.const 13 ;; len
/// /// call $log_str)
/// For more information about this function, see [`Func::wrap1`]. /// (memory (export "memory") 1)
(wrap10, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10) /// (data (i32.const 4) "Hello, world!"))
/// "#,
/// Creates a new `Func` from the given Rust closure, which takes 11 /// )?;
/// arguments. /// let instance = Instance::new(&module, &[log_str.into()])?;
/// /// let foo = instance.exports()[0].func().unwrap().get0::<()>()?;
/// For more information about this function, see [`Func::wrap1`]. /// foo()?;
(wrap11, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11) /// # Ok(())
/// # }
/// Creates a new `Func` from the given Rust closure, which takes 12 /// ```
/// arguments. pub fn wrap<Params, Results>(store: &Store, func: impl IntoFunc<Params, Results>) -> Func {
/// func.into_func(store)
/// For more information about this function, see [`Func::wrap1`].
(wrap12, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12)
/// Creates a new `Func` from the given Rust closure, which takes 13
/// arguments.
///
/// For more information about this function, see [`Func::wrap1`].
(wrap13, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13)
/// Creates a new `Func` from the given Rust closure, which takes 14
/// arguments.
///
/// For more information about this function, see [`Func::wrap1`].
(wrap14, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14)
/// Creates a new `Func` from the given Rust closure, which takes 15
/// arguments.
///
/// For more information about this function, see [`Func::wrap1`].
(wrap15, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15)
} }
fn from_wrapped( fn from_wrapped(
@@ -634,7 +519,7 @@ impl Func {
/// instead this function jumps directly into JIT code. /// instead this function jumps directly into JIT code.
/// ///
/// For more information about which Rust types match up to which wasm /// For more information about which Rust types match up to which wasm
/// types, see the documentation on [`Func::wrap1`]. /// types, see the documentation on [`Func::wrap`].
/// ///
/// # Return /// # Return
/// ///
@@ -746,52 +631,36 @@ impl fmt::Debug for Func {
} }
/// A trait implemented for types which can be arguments to closures passed to /// A trait implemented for types which can be arguments to closures passed to
/// [`Func::wrap1`] and friends. /// [`Func::wrap`] and friends.
/// ///
/// This trait should not be implemented by user types. This trait may change at /// This trait should not be implemented by user types. This trait may change at
/// any time internally. The types which implement this trait, however, are /// any time internally. The types which implement this trait, however, are
/// stable over time. /// stable over time.
/// ///
/// For more information see [`Func::wrap1`] /// For more information see [`Func::wrap`]
pub trait WasmTy { pub unsafe trait WasmTy: Copy {
#[doc(hidden)]
type Abi: Copy;
#[doc(hidden)] #[doc(hidden)]
fn push(dst: &mut Vec<ValType>); fn push(dst: &mut Vec<ValType>);
#[doc(hidden)] #[doc(hidden)]
fn matches(tys: impl Iterator<Item = ValType>) -> anyhow::Result<()>; fn matches(tys: impl Iterator<Item = ValType>) -> anyhow::Result<()>;
#[doc(hidden)] #[doc(hidden)]
fn from_abi(vmctx: *mut VMContext, abi: Self::Abi) -> Self; unsafe fn load(ptr: &mut *const u128) -> Self;
#[doc(hidden)] #[doc(hidden)]
fn into_abi(self) -> Self::Abi; unsafe fn store(abi: Self, ptr: *mut u128);
#[doc(hidden)]
unsafe fn load(ptr: &mut *const u128) -> Self::Abi;
#[doc(hidden)]
unsafe fn store(abi: Self::Abi, ptr: *mut u128);
} }
impl WasmTy for () { unsafe impl WasmTy for () {
type Abi = ();
fn push(_dst: &mut Vec<ValType>) {} fn push(_dst: &mut Vec<ValType>) {}
fn matches(_tys: impl Iterator<Item = ValType>) -> anyhow::Result<()> { fn matches(_tys: impl Iterator<Item = ValType>) -> anyhow::Result<()> {
Ok(()) Ok(())
} }
#[inline] #[inline]
fn from_abi(_vmctx: *mut VMContext, abi: Self::Abi) -> Self { unsafe fn load(_ptr: &mut *const u128) -> Self {}
abi
}
#[inline] #[inline]
fn into_abi(self) -> Self::Abi { unsafe fn store(_abi: Self, _ptr: *mut u128) {}
self
}
#[inline]
unsafe fn load(_ptr: &mut *const u128) -> Self::Abi {}
#[inline]
unsafe fn store(_abi: Self::Abi, _ptr: *mut u128) {}
} }
impl WasmTy for i32 { unsafe impl WasmTy for i32 {
type Abi = Self;
fn push(dst: &mut Vec<ValType>) { fn push(dst: &mut Vec<ValType>) {
dst.push(ValType::I32); dst.push(ValType::I32);
} }
@@ -805,27 +674,18 @@ impl WasmTy for i32 {
Ok(()) Ok(())
} }
#[inline] #[inline]
fn from_abi(_vmctx: *mut VMContext, abi: Self::Abi) -> Self { unsafe fn load(ptr: &mut *const u128) -> Self {
abi
}
#[inline]
fn into_abi(self) -> Self::Abi {
self
}
#[inline]
unsafe fn load(ptr: &mut *const u128) -> Self::Abi {
let ret = **ptr as Self; let ret = **ptr as Self;
*ptr = (*ptr).add(1); *ptr = (*ptr).add(1);
return ret; return ret;
} }
#[inline] #[inline]
unsafe fn store(abi: Self::Abi, ptr: *mut u128) { unsafe fn store(abi: Self, ptr: *mut u128) {
*ptr = abi as u128; *ptr = abi as u128;
} }
} }
impl WasmTy for i64 { unsafe impl WasmTy for i64 {
type Abi = Self;
fn push(dst: &mut Vec<ValType>) { fn push(dst: &mut Vec<ValType>) {
dst.push(ValType::I64); dst.push(ValType::I64);
} }
@@ -839,27 +699,18 @@ impl WasmTy for i64 {
Ok(()) Ok(())
} }
#[inline] #[inline]
fn from_abi(_vmctx: *mut VMContext, abi: Self::Abi) -> Self { unsafe fn load(ptr: &mut *const u128) -> Self {
abi
}
#[inline]
fn into_abi(self) -> Self::Abi {
self
}
#[inline]
unsafe fn load(ptr: &mut *const u128) -> Self::Abi {
let ret = **ptr as Self; let ret = **ptr as Self;
*ptr = (*ptr).add(1); *ptr = (*ptr).add(1);
return ret; return ret;
} }
#[inline] #[inline]
unsafe fn store(abi: Self::Abi, ptr: *mut u128) { unsafe fn store(abi: Self, ptr: *mut u128) {
*ptr = abi as u128; *ptr = abi as u128;
} }
} }
impl WasmTy for f32 { unsafe impl WasmTy for f32 {
type Abi = Self;
fn push(dst: &mut Vec<ValType>) { fn push(dst: &mut Vec<ValType>) {
dst.push(ValType::F32); dst.push(ValType::F32);
} }
@@ -873,27 +724,18 @@ impl WasmTy for f32 {
Ok(()) Ok(())
} }
#[inline] #[inline]
fn from_abi(_vmctx: *mut VMContext, abi: Self::Abi) -> Self { unsafe fn load(ptr: &mut *const u128) -> Self {
abi
}
#[inline]
fn into_abi(self) -> Self::Abi {
self
}
#[inline]
unsafe fn load(ptr: &mut *const u128) -> Self::Abi {
let ret = f32::from_bits(**ptr as u32); let ret = f32::from_bits(**ptr as u32);
*ptr = (*ptr).add(1); *ptr = (*ptr).add(1);
return ret; return ret;
} }
#[inline] #[inline]
unsafe fn store(abi: Self::Abi, ptr: *mut u128) { unsafe fn store(abi: Self, ptr: *mut u128) {
*ptr = abi.to_bits() as u128; *ptr = abi.to_bits() as u128;
} }
} }
impl WasmTy for f64 { unsafe impl WasmTy for f64 {
type Abi = Self;
fn push(dst: &mut Vec<ValType>) { fn push(dst: &mut Vec<ValType>) {
dst.push(ValType::F64); dst.push(ValType::F64);
} }
@@ -907,34 +749,26 @@ impl WasmTy for f64 {
Ok(()) Ok(())
} }
#[inline] #[inline]
fn from_abi(_vmctx: *mut VMContext, abi: Self::Abi) -> Self { unsafe fn load(ptr: &mut *const u128) -> Self {
abi
}
#[inline]
fn into_abi(self) -> Self::Abi {
self
}
#[inline]
unsafe fn load(ptr: &mut *const u128) -> Self::Abi {
let ret = f64::from_bits(**ptr as u64); let ret = f64::from_bits(**ptr as u64);
*ptr = (*ptr).add(1); *ptr = (*ptr).add(1);
return ret; return ret;
} }
#[inline] #[inline]
unsafe fn store(abi: Self::Abi, ptr: *mut u128) { unsafe fn store(abi: Self, ptr: *mut u128) {
*ptr = abi.to_bits() as u128; *ptr = abi.to_bits() as u128;
} }
} }
/// A trait implemented for types which can be returned from closures passed to /// A trait implemented for types which can be returned from closures passed to
/// [`Func::wrap1`] and friends. /// [`Func::wrap`] and friends.
/// ///
/// This trait should not be implemented by user types. This trait may change at /// This trait should not be implemented by user types. This trait may change at
/// any time internally. The types which implement this trait, however, are /// any time internally. The types which implement this trait, however, are
/// stable over time. /// stable over time.
/// ///
/// For more information see [`Func::wrap1`] /// For more information see [`Func::wrap`]
pub trait WasmRet { pub unsafe trait WasmRet {
#[doc(hidden)] #[doc(hidden)]
type Abi; type Abi;
#[doc(hidden)] #[doc(hidden)]
@@ -947,8 +781,8 @@ pub trait WasmRet {
unsafe fn store(abi: Self::Abi, ptr: *mut u128); unsafe fn store(abi: Self::Abi, ptr: *mut u128);
} }
impl<T: WasmTy> WasmRet for T { unsafe impl<T: WasmTy> WasmRet for T {
type Abi = T::Abi; type Abi = T;
fn push(dst: &mut Vec<ValType>) { fn push(dst: &mut Vec<ValType>) {
T::push(dst) T::push(dst)
} }
@@ -959,7 +793,7 @@ impl<T: WasmTy> WasmRet for T {
#[inline] #[inline]
fn into_abi(self) -> Self::Abi { fn into_abi(self) -> Self::Abi {
T::into_abi(self) self
} }
#[inline] #[inline]
@@ -968,8 +802,8 @@ impl<T: WasmTy> WasmRet for T {
} }
} }
impl<T: WasmTy> WasmRet for Result<T, Trap> { unsafe impl<T: WasmTy> WasmRet for Result<T, Trap> {
type Abi = T::Abi; type Abi = T;
fn push(dst: &mut Vec<ValType>) { fn push(dst: &mut Vec<ValType>) {
T::push(dst) T::push(dst)
} }
@@ -995,3 +829,198 @@ impl<T: WasmTy> WasmRet for Result<T, Trap> {
T::store(abi, ptr); T::store(abi, ptr);
} }
} }
/// Internal trait implemented for all arguments that can be passed to
/// [`Func::wrap`].
///
/// This trait should not be implemented by external users, it's only intended
/// as an implementation detail of this crate.
pub trait IntoFunc<Params, Results> {
#[doc(hidden)]
fn into_func(self, store: &Store) -> Func;
}
/// A structure representing the *caller's* context when creating a function
/// via [`Func::wrap`].
///
/// This structure can be taken as the first parameter of a closure passed to
/// [`Func::wrap`], and it can be used to learn information about the caller of
/// the function, such as the calling module's memory, exports, etc.
///
/// The primary purpose of this structure is to provide access to the
/// caller's information, such as it's exported memory. This allows
/// functions which take pointers as arguments to easily read the memory the
/// pointers point into.
///
/// Note that this is intended to be a pretty temporary mechanism for accessing
/// the caller's memory until interface types has been fully standardized and
/// implemented.
pub struct Caller<'a> {
store: &'a Store,
caller_vmctx: *mut VMContext,
}
impl Caller<'_> {
/// Looks up an export from the caller's module by the `name` given.
///
/// Note that this function is only implemented for the `Extern::Memory`
/// type currently. No other exported structure can be acquired through this
/// just yet, but this may be implemented in the future!
///
/// # Return
///
/// If a memory export with the `name` provided was found, then it is
/// returned as a `Memory`. There are a number of situations, however, where
/// the memory may not be available:
///
/// * The caller instance may not have an export named `name`
/// * The export named `name` may not be an exported memory
/// * There may not be a caller available, for example if `Func` was called
/// directly from host code.
///
/// It's recommended to take care when calling this API and gracefully
/// handling a `None` return value.
pub fn get_export(&self, name: &str) -> Option<Extern> {
unsafe {
if self.caller_vmctx.is_null() {
return None;
}
let instance = InstanceHandle::from_vmctx(self.caller_vmctx);
let export = match instance.lookup(name) {
Some(Export::Memory(m)) => m,
_ => return None,
};
let mem = Memory::from_wasmtime_memory(export, self.store, instance);
Some(Extern::Memory(mem))
}
}
}
macro_rules! impl_into_func {
($(
($($args:ident)*)
)*) => ($(
// Implement for functions without a leading `&Caller` parameter,
// delegating to the implementation below which does have the leading
// `Caller` parameter.
impl<F, $($args,)* R> IntoFunc<($($args,)*), R> for F
where
F: Fn($($args),*) -> R + 'static,
$($args: WasmTy,)*
R: WasmRet,
{
#[allow(non_snake_case)]
fn into_func(self, store: &Store) -> Func {
Func::wrap(store, move |_: Caller<'_>, $($args:$args),*| {
self($($args),*)
})
}
}
#[allow(non_snake_case)]
impl<F, $($args,)* R> IntoFunc<(Caller<'_>, $($args,)*), R> for F
where
F: Fn(Caller<'_>, $($args),*) -> R + 'static,
$($args: WasmTy,)*
R: WasmRet,
{
fn into_func(self, store: &Store) -> Func {
// Note that this shim's ABI must match that expected by
// cranelift, since cranelift is generating raw function calls
// directly to this function.
unsafe extern "C" fn shim<F, $($args,)* R>(
vmctx: *mut VMContext,
caller_vmctx: *mut VMContext,
$($args: $args,)*
) -> R::Abi
where
F: Fn(Caller<'_>, $($args),*) -> R + 'static,
$($args: WasmTy,)*
R: WasmRet,
{
let ret = {
let instance = InstanceHandle::from_vmctx(vmctx);
let (func, store) = instance.host_state().downcast_ref::<(F, Store)>().expect("state");
panic::catch_unwind(AssertUnwindSafe(|| {
func(
Caller { store, caller_vmctx },
$($args,)*
)
}))
};
match ret {
Ok(ret) => ret.into_abi(),
Err(panic) => wasmtime_runtime::resume_panic(panic),
}
}
unsafe extern "C" fn trampoline<$($args,)* R>(
callee_vmctx: *mut VMContext,
caller_vmctx: *mut VMContext,
ptr: *const VMFunctionBody,
args: *mut u128,
)
where
$($args: WasmTy,)*
R: WasmRet,
{
let ptr = mem::transmute::<
*const VMFunctionBody,
unsafe extern "C" fn(
*mut VMContext,
*mut VMContext,
$($args,)*
) -> R::Abi,
>(ptr);
let mut _next = args as *const u128;
$(let $args = $args::load(&mut _next);)*
let ret = ptr(callee_vmctx, caller_vmctx, $($args),*);
R::store(ret, args);
}
let mut _args = Vec::new();
$($args::push(&mut _args);)*
let mut ret = Vec::new();
R::push(&mut ret);
let ty = FuncType::new(_args.into(), ret.into());
let store_clone = store.clone();
unsafe {
let trampoline = trampoline::<$($args,)* R>;
let (instance, export) = crate::trampoline::generate_raw_func_export(
&ty,
std::slice::from_raw_parts_mut(
shim::<F, $($args,)* R> as *mut _,
0,
),
trampoline,
store,
Box::new((self, store_clone)),
)
.expect("failed to generate export");
let callable = Rc::new(WasmtimeFn::new(store, instance, export, trampoline));
Func::from_wrapped(store, ty, callable)
}
}
}
)*)
}
impl_into_func! {
()
(A1)
(A1 A2)
(A1 A2 A3)
(A1 A2 A3 A4)
(A1 A2 A3 A4 A5)
(A1 A2 A3 A4 A5 A6)
(A1 A2 A3 A4 A5 A6 A7)
(A1 A2 A3 A4 A5 A6 A7 A8)
(A1 A2 A3 A4 A5 A6 A7 A8 A9)
(A1 A2 A3 A4 A5 A6 A7 A8 A9 A10)
(A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11)
(A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12)
(A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12 A13)
(A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12 A13 A14)
(A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12 A13 A14 A15)
}

2
crates/api/src/lib.rs
View File

@@ -24,7 +24,7 @@ mod values;
pub use crate::callable::Callable; pub use crate::callable::Callable;
pub use crate::externals::*; pub use crate::externals::*;
pub use crate::frame_info::FrameInfo; pub use crate::frame_info::FrameInfo;
pub use crate::func::{Func, WasmRet, WasmTy}; pub use crate::func::*;
pub use crate::instance::Instance; pub use crate::instance::Instance;
pub use crate::module::Module; pub use crate::module::Module;
pub use crate::r#ref::{AnyRef, HostInfo, HostRef}; pub use crate::r#ref::{AnyRef, HostInfo, HostRef};

6
crates/api/tests/externals.rs
View File

@@ -62,7 +62,7 @@ fn cross_store() -> anyhow::Result<()> {
// ============ Cross-store instantiation ============== // ============ Cross-store instantiation ==============
let func = Func::wrap0(&store2, || {}); let func = Func::wrap(&store2, || {});
let ty = GlobalType::new(ValType::I32, Mutability::Const); let ty = GlobalType::new(ValType::I32, Mutability::Const);
let global = Global::new(&store2, ty, Val::I32(0))?; let global = Global::new(&store2, ty, Val::I32(0))?;
let ty = MemoryType::new(Limits::new(1, None)); let ty = MemoryType::new(Limits::new(1, None));
@@ -84,8 +84,8 @@ fn cross_store() -> anyhow::Result<()> {
// ============ Cross-store globals ============== // ============ Cross-store globals ==============
let store1val = Val::FuncRef(Func::wrap0(&store1, || {})); let store1val = Val::FuncRef(Func::wrap(&store1, || {}));
let store2val = Val::FuncRef(Func::wrap0(&store2, || {})); let store2val = Val::FuncRef(Func::wrap(&store2, || {}));
let ty = GlobalType::new(ValType::FuncRef, Mutability::Var); let ty = GlobalType::new(ValType::FuncRef, Mutability::Var);
assert!(Global::new(&store2, ty.clone(), store1val.clone()).is_err()); assert!(Global::new(&store2, ty.clone(), store1val.clone()).is_err());

147
crates/api/tests/func.rs
View File

@@ -1,25 +1,25 @@
use anyhow::Result; use anyhow::Result;
use std::rc::Rc; use std::rc::Rc;
use std::sync::atomic::{AtomicUsize, Ordering::SeqCst}; use std::sync::atomic::{AtomicUsize, Ordering::SeqCst};
use wasmtime::{Callable, Func, FuncType, Instance, Module, Store, Trap, Val, ValType}; use wasmtime::*;
#[test] #[test]
fn func_constructors() { fn func_constructors() {
let store = Store::default(); let store = Store::default();
Func::wrap0(&store, || {}); Func::wrap(&store, || {});
Func::wrap1(&store, |_: i32| {}); Func::wrap(&store, |_: i32| {});
Func::wrap2(&store, |_: i32, _: i64| {}); Func::wrap(&store, |_: i32, _: i64| {});
Func::wrap2(&store, |_: f32, _: f64| {}); Func::wrap(&store, |_: f32, _: f64| {});
Func::wrap0(&store, || -> i32 { 0 }); Func::wrap(&store, || -> i32 { 0 });
Func::wrap0(&store, || -> i64 { 0 }); Func::wrap(&store, || -> i64 { 0 });
Func::wrap0(&store, || -> f32 { 0.0 }); Func::wrap(&store, || -> f32 { 0.0 });
Func::wrap0(&store, || -> f64 { 0.0 }); Func::wrap(&store, || -> f64 { 0.0 });
Func::wrap0(&store, || -> Result<(), Trap> { loop {} }); Func::wrap(&store, || -> Result<(), Trap> { loop {} });
Func::wrap0(&store, || -> Result<i32, Trap> { loop {} }); Func::wrap(&store, || -> Result<i32, Trap> { loop {} });
Func::wrap0(&store, || -> Result<i64, Trap> { loop {} }); Func::wrap(&store, || -> Result<i64, Trap> { loop {} });
Func::wrap0(&store, || -> Result<f32, Trap> { loop {} }); Func::wrap(&store, || -> Result<f32, Trap> { loop {} });
Func::wrap0(&store, || -> Result<f64, Trap> { loop {} }); Func::wrap(&store, || -> Result<f64, Trap> { loop {} });
} }
#[test] #[test]
@@ -37,7 +37,7 @@ fn dtor_runs() {
let store = Store::default(); let store = Store::default();
let a = A; let a = A;
assert_eq!(HITS.load(SeqCst), 0); assert_eq!(HITS.load(SeqCst), 0);
Func::wrap0(&store, move || { Func::wrap(&store, move || {
drop(&a); drop(&a);
}); });
assert_eq!(HITS.load(SeqCst), 1); assert_eq!(HITS.load(SeqCst), 1);
@@ -57,7 +57,7 @@ fn dtor_delayed() -> Result<()> {
let store = Store::default(); let store = Store::default();
let a = A; let a = A;
let func = Func::wrap0(&store, move || drop(&a)); let func = Func::wrap(&store, move || drop(&a));
assert_eq!(HITS.load(SeqCst), 0); assert_eq!(HITS.load(SeqCst), 0);
let wasm = wat::parse_str(r#"(import "" "" (func))"#)?; let wasm = wat::parse_str(r#"(import "" "" (func))"#)?;
@@ -73,27 +73,27 @@ fn dtor_delayed() -> Result<()> {
fn signatures_match() { fn signatures_match() {
let store = Store::default(); let store = Store::default();
let f = Func::wrap0(&store, || {}); let f = Func::wrap(&store, || {});
assert_eq!(f.ty().params(), &[]); assert_eq!(f.ty().params(), &[]);
assert_eq!(f.ty().results(), &[]); assert_eq!(f.ty().results(), &[]);
let f = Func::wrap0(&store, || -> i32 { loop {} }); let f = Func::wrap(&store, || -> i32 { loop {} });
assert_eq!(f.ty().params(), &[]); assert_eq!(f.ty().params(), &[]);
assert_eq!(f.ty().results(), &[ValType::I32]); assert_eq!(f.ty().results(), &[ValType::I32]);
let f = Func::wrap0(&store, || -> i64 { loop {} }); let f = Func::wrap(&store, || -> i64 { loop {} });
assert_eq!(f.ty().params(), &[]); assert_eq!(f.ty().params(), &[]);
assert_eq!(f.ty().results(), &[ValType::I64]); assert_eq!(f.ty().results(), &[ValType::I64]);
let f = Func::wrap0(&store, || -> f32 { loop {} }); let f = Func::wrap(&store, || -> f32 { loop {} });
assert_eq!(f.ty().params(), &[]); assert_eq!(f.ty().params(), &[]);
assert_eq!(f.ty().results(), &[ValType::F32]); assert_eq!(f.ty().results(), &[ValType::F32]);
let f = Func::wrap0(&store, || -> f64 { loop {} }); let f = Func::wrap(&store, || -> f64 { loop {} });
assert_eq!(f.ty().params(), &[]); assert_eq!(f.ty().params(), &[]);
assert_eq!(f.ty().results(), &[ValType::F64]); assert_eq!(f.ty().results(), &[ValType::F64]);
let f = Func::wrap5(&store, |_: f32, _: f64, _: i32, _: i64, _: i32| -> f64 { let f = Func::wrap(&store, |_: f32, _: f64, _: i32, _: i64, _: i32| -> f64 {
loop {} loop {}
}); });
assert_eq!( assert_eq!(
@@ -144,23 +144,23 @@ fn import_works() -> Result<()> {
Instance::new( Instance::new(
&module, &module,
&[ &[
Func::wrap0(&store, || { Func::wrap(&store, || {
assert_eq!(HITS.fetch_add(1, SeqCst), 0); assert_eq!(HITS.fetch_add(1, SeqCst), 0);
}) })
.into(), .into(),
Func::wrap1(&store, |x: i32| -> i32 { Func::wrap(&store, |x: i32| -> i32 {
assert_eq!(x, 0); assert_eq!(x, 0);
assert_eq!(HITS.fetch_add(1, SeqCst), 1); assert_eq!(HITS.fetch_add(1, SeqCst), 1);
1 1
}) })
.into(), .into(),
Func::wrap2(&store, |x: i32, y: i64| { Func::wrap(&store, |x: i32, y: i64| {
assert_eq!(x, 2); assert_eq!(x, 2);
assert_eq!(y, 3); assert_eq!(y, 3);
assert_eq!(HITS.fetch_add(1, SeqCst), 2); assert_eq!(HITS.fetch_add(1, SeqCst), 2);
}) })
.into(), .into(),
Func::wrap5(&store, |a: i32, b: i64, c: i32, d: f32, e: f64| { Func::wrap(&store, |a: i32, b: i64, c: i32, d: f32, e: f64| {
assert_eq!(a, 100); assert_eq!(a, 100);
assert_eq!(b, 200); assert_eq!(b, 200);
assert_eq!(c, 300); assert_eq!(c, 300);
@@ -177,7 +177,7 @@ fn import_works() -> Result<()> {
#[test] #[test]
fn trap_smoke() { fn trap_smoke() {
let store = Store::default(); let store = Store::default();
let f = Func::wrap0(&store, || -> Result<(), Trap> { Err(Trap::new("test")) }); let f = Func::wrap(&store, || -> Result<(), Trap> { Err(Trap::new("test")) });
let err = f.call(&[]).unwrap_err(); let err = f.call(&[]).unwrap_err();
assert_eq!(err.message(), "test"); assert_eq!(err.message(), "test");
} }
@@ -194,7 +194,7 @@ fn trap_import() -> Result<()> {
let module = Module::new(&store, &wasm)?; let module = Module::new(&store, &wasm)?;
let trap = Instance::new( let trap = Instance::new(
&module, &module,
&[Func::wrap0(&store, || -> Result<(), Trap> { Err(Trap::new("foo")) }).into()], &[Func::wrap(&store, || -> Result<(), Trap> { Err(Trap::new("foo")) }).into()],
) )
.err() .err()
.unwrap() .unwrap()
@@ -206,7 +206,7 @@ fn trap_import() -> Result<()> {
#[test] #[test]
fn get_from_wrapper() { fn get_from_wrapper() {
let store = Store::default(); let store = Store::default();
let f = Func::wrap0(&store, || {}); let f = Func::wrap(&store, || {});
assert!(f.get0::<()>().is_ok()); assert!(f.get0::<()>().is_ok());
assert!(f.get0::<i32>().is_err()); assert!(f.get0::<i32>().is_err());
assert!(f.get1::<(), ()>().is_ok()); assert!(f.get1::<(), ()>().is_ok());
@@ -216,23 +216,23 @@ fn get_from_wrapper() {
assert!(f.get2::<i32, i32, ()>().is_err()); assert!(f.get2::<i32, i32, ()>().is_err());
assert!(f.get2::<i32, i32, i32>().is_err()); assert!(f.get2::<i32, i32, i32>().is_err());
let f = Func::wrap0(&store, || -> i32 { loop {} }); let f = Func::wrap(&store, || -> i32 { loop {} });
assert!(f.get0::<i32>().is_ok()); assert!(f.get0::<i32>().is_ok());
let f = Func::wrap0(&store, || -> f32 { loop {} }); let f = Func::wrap(&store, || -> f32 { loop {} });
assert!(f.get0::<f32>().is_ok()); assert!(f.get0::<f32>().is_ok());
let f = Func::wrap0(&store, || -> f64 { loop {} }); let f = Func::wrap(&store, || -> f64 { loop {} });
assert!(f.get0::<f64>().is_ok()); assert!(f.get0::<f64>().is_ok());
let f = Func::wrap1(&store, |_: i32| {}); let f = Func::wrap(&store, |_: i32| {});
assert!(f.get1::<i32, ()>().is_ok()); assert!(f.get1::<i32, ()>().is_ok());
assert!(f.get1::<i64, ()>().is_err()); assert!(f.get1::<i64, ()>().is_err());
assert!(f.get1::<f32, ()>().is_err()); assert!(f.get1::<f32, ()>().is_err());
assert!(f.get1::<f64, ()>().is_err()); assert!(f.get1::<f64, ()>().is_err());
let f = Func::wrap1(&store, |_: i64| {}); let f = Func::wrap(&store, |_: i64| {});
assert!(f.get1::<i64, ()>().is_ok()); assert!(f.get1::<i64, ()>().is_ok());
let f = Func::wrap1(&store, |_: f32| {}); let f = Func::wrap(&store, |_: f32| {});
assert!(f.get1::<f32, ()>().is_ok()); assert!(f.get1::<f32, ()>().is_ok());
let f = Func::wrap1(&store, |_: f64| {}); let f = Func::wrap(&store, |_: f64| {});
assert!(f.get1::<f64, ()>().is_ok()); assert!(f.get1::<f64, ()>().is_ok());
} }
@@ -293,7 +293,7 @@ fn get_from_module() -> anyhow::Result<()> {
#[test] #[test]
fn call_wrapped_func() -> Result<()> { fn call_wrapped_func() -> Result<()> {
let store = Store::default(); let store = Store::default();
let f = Func::wrap4(&store, |a: i32, b: i64, c: f32, d: f64| { let f = Func::wrap(&store, |a: i32, b: i64, c: f32, d: f64| {
assert_eq!(a, 1); assert_eq!(a, 1);
assert_eq!(b, 2); assert_eq!(b, 2);
assert_eq!(c, 3.0); assert_eq!(c, 3.0);
@@ -302,28 +302,93 @@ fn call_wrapped_func() -> Result<()> {
f.call(&[Val::I32(1), Val::I64(2), 3.0f32.into(), 4.0f64.into()])?; f.call(&[Val::I32(1), Val::I64(2), 3.0f32.into(), 4.0f64.into()])?;
f.get4::<i32, i64, f32, f64, ()>()?(1, 2, 3.0, 4.0)?; f.get4::<i32, i64, f32, f64, ()>()?(1, 2, 3.0, 4.0)?;
let f = Func::wrap0(&store, || 1i32); let f = Func::wrap(&store, || 1i32);
let results = f.call(&[])?; let results = f.call(&[])?;
assert_eq!(results.len(), 1); assert_eq!(results.len(), 1);
assert_eq!(results[0].unwrap_i32(), 1); assert_eq!(results[0].unwrap_i32(), 1);
assert_eq!(f.get0::<i32>()?()?, 1); assert_eq!(f.get0::<i32>()?()?, 1);
let f = Func::wrap0(&store, || 2i64); let f = Func::wrap(&store, || 2i64);
let results = f.call(&[])?; let results = f.call(&[])?;
assert_eq!(results.len(), 1); assert_eq!(results.len(), 1);
assert_eq!(results[0].unwrap_i64(), 2); assert_eq!(results[0].unwrap_i64(), 2);
assert_eq!(f.get0::<i64>()?()?, 2); assert_eq!(f.get0::<i64>()?()?, 2);
let f = Func::wrap0(&store, || 3.0f32); let f = Func::wrap(&store, || 3.0f32);
let results = f.call(&[])?; let results = f.call(&[])?;
assert_eq!(results.len(), 1); assert_eq!(results.len(), 1);
assert_eq!(results[0].unwrap_f32(), 3.0); assert_eq!(results[0].unwrap_f32(), 3.0);
assert_eq!(f.get0::<f32>()?()?, 3.0); assert_eq!(f.get0::<f32>()?()?, 3.0);
let f = Func::wrap0(&store, || 4.0f64); let f = Func::wrap(&store, || 4.0f64);
let results = f.call(&[])?; let results = f.call(&[])?;
assert_eq!(results.len(), 1); assert_eq!(results.len(), 1);
assert_eq!(results[0].unwrap_f64(), 4.0); assert_eq!(results[0].unwrap_f64(), 4.0);
assert_eq!(f.get0::<f64>()?()?, 4.0); assert_eq!(f.get0::<f64>()?()?, 4.0);
Ok(()) Ok(())
} }
#[test]
fn caller_memory() -> anyhow::Result<()> {
let store = Store::default();
let f = Func::wrap(&store, |c: Caller<'_>| {
assert!(c.get_export("x").is_none());
assert!(c.get_export("y").is_none());
assert!(c.get_export("z").is_none());
});
f.call(&[])?;
let f = Func::wrap(&store, |c: Caller<'_>| {
assert!(c.get_export("x").is_none());
});
let module = Module::new(
&store,
r#"
(module
(import "" "" (func $f))
(start $f)
)
"#,
)?;
Instance::new(&module, &[f.into()])?;
let f = Func::wrap(&store, |c: Caller<'_>| {
assert!(c.get_export("memory").is_some());
});
let module = Module::new(
&store,
r#"
(module
(import "" "" (func $f))
(memory (export "memory") 1)
(start $f)
)
"#,
)?;
Instance::new(&module, &[f.into()])?;
let f = Func::wrap(&store, |c: Caller<'_>| {
assert!(c.get_export("m").is_some());
assert!(c.get_export("f").is_none());
assert!(c.get_export("g").is_none());
assert!(c.get_export("t").is_none());
});
let module = Module::new(
&store,
r#"
(module
(import "" "" (func $f))
(memory (export "m") 1)
(func (export "f"))
(global (export "g") i32 (i32.const 0))
(table (export "t") 1 funcref)
(start $f)
)
"#,
)?;
Instance::new(&module, &[f.into()])?;
Ok(())
}

4
crates/api/tests/traps.rs
View File

@@ -278,7 +278,7 @@ fn rust_panic_import() -> Result<()> {
&module, &module,
&[ &[
func.into(), func.into(),
Func::wrap0(&store, || panic!("this is another panic")).into(), Func::wrap(&store, || panic!("this is another panic")).into(),
], ],
)?; )?;
let func = instance.exports()[0].func().unwrap().clone(); let func = instance.exports()[0].func().unwrap().clone();
@@ -329,7 +329,7 @@ fn rust_panic_start_function() -> Result<()> {
.unwrap_err(); .unwrap_err();
assert_eq!(err.downcast_ref::<&'static str>(), Some(&"this is a panic")); assert_eq!(err.downcast_ref::<&'static str>(), Some(&"this is a panic"));
let func = Func::wrap0(&store, || panic!("this is another panic")); let func = Func::wrap(&store, || panic!("this is another panic"));
let err = panic::catch_unwind(AssertUnwindSafe(|| { let err = panic::catch_unwind(AssertUnwindSafe(|| {
drop(Instance::new(&module, &[func.into()])); drop(Instance::new(&module, &[func.into()]));
})) }))

16
crates/wasi-common/wig/src/wasi.rs
View File

@@ -182,24 +182,26 @@ pub fn define_struct(args: TokenStream) -> TokenStream {
} }
let format_str = format!("{}({})", name, formats.join(", ")); let format_str = format!("{}({})", name, formats.join(", "));
let wrap = format_ident!("wrap{}", shim_arg_decls.len() + 1);
ctor_externs.push(quote! { ctor_externs.push(quote! {
let my_cx = cx.clone(); let my_cx = cx.clone();
let #name_ident = wasmtime::Func::#wrap( let #name_ident = wasmtime::Func::wrap(
store, store,
move |mem: crate::WasiCallerMemory #(,#shim_arg_decls)*| -> #ret_ty { move |caller: wasmtime::Caller<'_> #(,#shim_arg_decls)*| -> #ret_ty {
log::trace!( log::trace!(
#format_str, #format_str,
#(#format_args),* #(#format_args),*
); );
unsafe { unsafe {
let memory = match mem.get() { let memory = match caller.get_export("memory") {
Ok(e) => e, Some(wasmtime::Extern::Memory(m)) => m,
Err(e) => #handle_early_error, _ => {
let e = wasi_common::wasi::__WASI_ERRNO_INVAL;
#handle_early_error
}
}; };
hostcalls::#name_ident( hostcalls::#name_ident(
&mut my_cx.borrow_mut(), &mut my_cx.borrow_mut(),
memory, memory.data_unchecked_mut(),
#(#hostcall_args),* #(#hostcall_args),*
) #cvt_ret ) #cvt_ret
} }

55
crates/wasi/src/lib.rs
View File

@@ -16,58 +16,3 @@ pub fn is_wasi_module(name: &str) -> bool {
// trick. // trick.
name.starts_with("wasi") name.starts_with("wasi")
} }
/// This is an internal structure used to acquire a handle on the caller's
/// wasm memory buffer.
///
/// This exploits how we can implement `WasmTy` for ourselves locally even
/// though crates in general should not be doing that. This is a crate in
/// the wasmtime project, however, so we should be able to keep up with our own
/// changes.
///
/// In general this type is wildly unsafe. We need to update the wasi crates to
/// probably work with more `wasmtime`-like APIs to grip with the unsafety
/// around dealing with caller memory.
struct WasiCallerMemory {
base: *mut u8,
len: usize,
}
impl wasmtime::WasmTy for WasiCallerMemory {
type Abi = ();
fn push(_dst: &mut Vec<wasmtime::ValType>) {}
fn matches(_tys: impl Iterator<Item = wasmtime::ValType>) -> anyhow::Result<()> {
Ok(())
}
fn from_abi(vmctx: *mut wasmtime_runtime::VMContext, _abi: ()) -> Self {
unsafe {
match wasmtime_runtime::InstanceHandle::from_vmctx(vmctx).lookup("memory") {
Some(wasmtime_runtime::Export::Memory(m)) => WasiCallerMemory {
base: (*m.definition).base,
len: (*m.definition).current_length,
},
_ => WasiCallerMemory {
base: std::ptr::null_mut(),
len: 0,
},
}
}
}
fn into_abi(self) {}
unsafe fn load(_ptr: &mut *const u128) {}
unsafe fn store(_abi: Self::Abi, _ptr: *mut u128) {}
}
impl WasiCallerMemory {
unsafe fn get(&self) -> Result<&mut [u8], wasi_common::wasi::__wasi_errno_t> {
if self.base.is_null() {
Err(wasi_common::wasi::__WASI_ERRNO_INVAL)
} else {
Ok(std::slice::from_raw_parts_mut(self.base, self.len))
}
}
}

14
crates/wast/src/spectest.rs
View File

@@ -6,28 +6,28 @@ use wasmtime::*;
pub fn instantiate_spectest(store: &Store) -> HashMap<&'static str, Extern> { pub fn instantiate_spectest(store: &Store) -> HashMap<&'static str, Extern> {
let mut ret = HashMap::new(); let mut ret = HashMap::new();
let func = Func::wrap0(store, || {}); let func = Func::wrap(store, || {});
ret.insert("print", Extern::Func(func)); ret.insert("print", Extern::Func(func));
let func = Func::wrap1(store, |val: i32| println!("{}: i32", val)); let func = Func::wrap(store, |val: i32| println!("{}: i32", val));
ret.insert("print_i32", Extern::Func(func)); ret.insert("print_i32", Extern::Func(func));
let func = Func::wrap1(store, |val: i64| println!("{}: i64", val)); let func = Func::wrap(store, |val: i64| println!("{}: i64", val));
ret.insert("print_i64", Extern::Func(func)); ret.insert("print_i64", Extern::Func(func));
let func = Func::wrap1(store, |val: f32| println!("{}: f32", val)); let func = Func::wrap(store, |val: f32| println!("{}: f32", val));
ret.insert("print_f32", Extern::Func(func)); ret.insert("print_f32", Extern::Func(func));
let func = Func::wrap1(store, |val: f64| println!("{}: f64", val)); let func = Func::wrap(store, |val: f64| println!("{}: f64", val));
ret.insert("print_f64", Extern::Func(func)); ret.insert("print_f64", Extern::Func(func));
let func = Func::wrap2(store, |i: i32, f: f32| { let func = Func::wrap(store, |i: i32, f: f32| {
println!("{}: i32", i); println!("{}: i32", i);
println!("{}: f32", f); println!("{}: f32", f);
}); });
ret.insert("print_i32_f32", Extern::Func(func)); ret.insert("print_i32_f32", Extern::Func(func));
let func = Func::wrap2(store, |f1: f64, f2: f64| { let func = Func::wrap(store, |f1: f64, f2: f64| {
println!("{}: f64", f1); println!("{}: f64", f1);
println!("{}: f64", f2); println!("{}: f64", f2);
}); });

4
docs/embed-rust.md
View File

@@ -149,12 +149,12 @@ looks like this:
# (import "" "double" (func $double (param i32) (result i32))))"#)?; # (import "" "double" (func $double (param i32) (result i32))))"#)?;
// First we can create our `log` function, which will simply print out the // First we can create our `log` function, which will simply print out the
// parameter it receives. // parameter it receives.
let log = Func::wrap1(&store, |param: i32| { let log = Func::wrap(&store, |param: i32| {
println!("log: {}", param); println!("log: {}", param);
}); });
// Next we can create our double function which doubles the input it receives. // Next we can create our double function which doubles the input it receives.
let double = Func::wrap1(&store, |param: i32| param * 2); let double = Func::wrap(&store, |param: i32| param * 2);
// When instantiating the module we now need to provide the imports to the // When instantiating the module we now need to provide the imports to the
// instantiation process. This is the second slice argument, where each // instantiation process. This is the second slice argument, where each

2
examples/hello.rs
View File

@@ -20,7 +20,7 @@ fn main() -> Result<()> {
// Here we handle the imports of the module, which in this case is our // Here we handle the imports of the module, which in this case is our
// `HelloCallback` type and its associated implementation of `Callback. // `HelloCallback` type and its associated implementation of `Callback.
println!("Creating callback..."); println!("Creating callback...");
let hello_func = Func::wrap0(&store, || { let hello_func = Func::wrap(&store, || {
println!("Calling back..."); println!("Calling back...");
println!("> Hello World!"); println!("> Hello World!");
}); });