Enable warnings if async is disabled (#10145)

* Enable warnings if `async` is disabled

Continuation of work in #10131.

This required a number of organizational changes to help cut down on
`#[cfg]`, notably lots of async-related pieces from `store.rs` have
moved to `store/async_.rs` to avoid having lots of conditional imports.
Additionally this removes all of the `#[cfg]` annotations on those
methods already.

Additionally the signature of `AsyncCx::block_on` was updated to be a
bit more general to ideally remove the need for `Pin` but it ended up
not panning out quite just yet. In the future it should be possible to
remove the need for `Pin` at callsites though.

* Rebase conflicts

.github/workflows/main.yml

@@ -541,7 +541,7 @@ jobs:
           os: ubuntu-latest
           test: >
             cargo check -p wasmtime --no-default-features --features runtime,component-model &&
-            cargo check -p wasmtime --no-default-features --features runtime,gc,component-model &&
+            cargo check -p wasmtime --no-default-features --features runtime,gc,component-model,async &&
             cargo check -p cranelift-control --no-default-features &&
             cargo check -p pulley-interpreter --features encode,decode,disas,interp &&
             cargo check -p wasmtime-wasi-io --no-default-features
@@ -573,7 +573,7 @@ jobs:
         # A no_std target without 64-bit atomics
         - target: riscv32imac-unknown-none-elf
           os: ubuntu-latest
-          test: cargo check -p wasmtime --no-default-features --features runtime,gc,component-model
+          test: cargo check -p wasmtime --no-default-features --features runtime,gc,component-model,async
     env: ${{ matrix.env || fromJSON('{}') }}
     steps:
     - uses: actions/checkout@v4

crates/wasmtime/src/lib.rs

@@ -285,7 +285,6 @@
 // here to get warnings in all configurations of Wasmtime.
 #![cfg_attr(
     any(
-        not(feature = "async"),
         not(feature = "gc"),
         not(feature = "gc-drc"),
         not(feature = "gc-null"),

crates/wasmtime/src/runtime/component/linker.rs

@@ -9,9 +9,9 @@ use crate::hash_map::HashMap;
 use crate::prelude::*;
 use crate::{AsContextMut, Engine, Module, StoreContextMut};
 use alloc::sync::Arc;
-use core::future::Future;
 use core::marker;
-use core::pin::Pin;
+#[cfg(feature = "async")]
+use core::{future::Future, pin::Pin};
 use wasmtime_environ::component::{NameMap, NameMapIntern};
 use wasmtime_environ::PrimaryMap;
 
@@ -433,8 +433,8 @@ impl<T> LinkerInstance<'_, T> {
         );
         let ff = move |mut store: StoreContextMut<'_, T>, params: Params| -> Result<Return> {
             let async_cx = store.as_context_mut().0.async_cx().expect("async cx");
-            let mut future = Pin::from(f(store.as_context_mut(), params));
-            unsafe { async_cx.block_on(future.as_mut()) }?
+            let future = f(store.as_context_mut(), params);
+            unsafe { async_cx.block_on(Pin::from(future)) }?
         };
         self.func_wrap(name, ff)
     }
@@ -604,8 +604,8 @@ impl<T> LinkerInstance<'_, T> {
         );
         let ff = move |mut store: StoreContextMut<'_, T>, params: &[Val], results: &mut [Val]| {
             let async_cx = store.as_context_mut().0.async_cx().expect("async cx");
-            let mut future = Pin::from(f(store.as_context_mut(), params, results));
-            unsafe { async_cx.block_on(future.as_mut()) }?
+            let future = f(store.as_context_mut(), params, results);
+            unsafe { async_cx.block_on(Pin::from(future)) }?
         };
         self.func_new(name, ff)
     }
@@ -676,8 +676,8 @@ impl<T> LinkerInstance<'_, T> {
             &self.engine,
             move |mut cx: crate::Caller<'_, T>, (param,): (u32,)| {
                 let async_cx = cx.as_context_mut().0.async_cx().expect("async cx");
-                let mut future = Pin::from(dtor(cx.as_context_mut(), param));
-                match unsafe { async_cx.block_on(future.as_mut()) } {
+                let future = dtor(cx.as_context_mut(), param);
+                match unsafe { async_cx.block_on(Pin::from(future)) } {
                     Ok(Ok(())) => Ok(()),
                     Ok(Err(trap)) | Err(trap) => Err(trap),
                 }

crates/wasmtime/src/runtime/func.rs

@@ -12,11 +12,11 @@ use crate::{
 };
 use alloc::sync::Arc;
 use core::ffi::c_void;
-use core::future::Future;
 use core::mem::{self, MaybeUninit};
 use core::num::NonZeroUsize;
-use core::pin::Pin;
 use core::ptr::NonNull;
+#[cfg(feature = "async")]
+use core::{future::Future, pin::Pin};
 use wasmtime_environ::VMSharedTypeIndex;
 
 /// A reference to the abstract `nofunc` heap value.
@@ -563,8 +563,8 @@ impl Func {
                 .0
                 .async_cx()
                 .expect("Attempt to spawn new action on dying fiber");
-            let mut future = Pin::from(func(caller, params, results));
-            match unsafe { async_cx.block_on(future.as_mut()) } {
+            let future = func(caller, params, results);
+            match unsafe { async_cx.block_on(Pin::from(future)) } {
                 Ok(Ok(())) => Ok(()),
                 Ok(Err(trap)) | Err(trap) => Err(trap),
             }
@@ -838,6 +838,7 @@ impl Func {
         }
     }
 
+    #[cfg(feature = "async")]
     fn wrap_inner<F, T, Params, Results>(mut store: impl AsContextMut<Data = T>, func: F) -> Func
     where
         F: Fn(Caller<'_, T>, Params) -> Results + Send + Sync + 'static,
@@ -881,9 +882,9 @@ impl Func {
                 .0
                 .async_cx()
                 .expect("Attempt to start async function on dying fiber");
-            let mut future = Pin::from(func(caller, args));
+            let future = func(caller, args);
 
-            match unsafe { async_cx.block_on(future.as_mut()) } {
+            match unsafe { async_cx.block_on(Pin::from(future)) } {
                 Ok(ret) => ret.into_fallible(),
                 Err(e) => R::fallible_from_error(e),
             }

crates/wasmtime/src/runtime/linker.rs

@@ -5,15 +5,13 @@ use crate::store::StoreOpaque;
 use crate::{prelude::*, IntoFunc};
 use crate::{
     AsContext, AsContextMut, Caller, Engine, Extern, ExternType, Func, FuncType, ImportType,
-    Instance, Module, StoreContextMut, Val, ValRaw, ValType, WasmTyList,
+    Instance, Module, StoreContextMut, Val, ValRaw, ValType,
 };
 use alloc::sync::Arc;
 use core::fmt;
-#[cfg(feature = "async")]
-use core::future::Future;
 use core::marker;
 #[cfg(feature = "async")]
-use core::pin::Pin;
+use core::{future::Future, pin::Pin};
 use log::warn;
 
 /// Structure used to link wasm modules/instances together.
@@ -465,8 +463,8 @@ impl<T> Linker<T> {
                 .0
                 .async_cx()
                 .expect("Attempt to spawn new function on dying fiber");
-            let mut future = Pin::from(func(caller, params, results));
-            match unsafe { async_cx.block_on(future.as_mut()) } {
+            let future = func(caller, params, results);
+            match unsafe { async_cx.block_on(Pin::from(future)) } {
                 Ok(Ok(())) => Ok(()),
                 Ok(Err(trap)) | Err(trap) => Err(trap),
             }
@@ -543,7 +541,7 @@ impl<T> Linker<T> {
 
     /// Asynchronous analog of [`Linker::func_wrap`].
     #[cfg(feature = "async")]
-    pub fn func_wrap_async<F, Params: WasmTyList, Args: crate::WasmRet>(
+    pub fn func_wrap_async<F, Params: crate::WasmTyList, Args: crate::WasmRet>(
         &mut self,
         module: &str,
         name: &str,
@@ -568,8 +566,8 @@ impl<T> Linker<T> {
                     .0
                     .async_cx()
                     .expect("Attempt to start async function on dying fiber");
-                let mut future = Pin::from(func(caller, args));
-                match unsafe { async_cx.block_on(future.as_mut()) } {
+                let future = func(caller, args);
+                match unsafe { async_cx.block_on(Pin::from(future)) } {
                     Ok(ret) => ret.into_fallible(),
                     Err(e) => Args::fallible_from_error(e),
                 }