Enable unsafe-attr-outside-unsafe 2024 edition lint (bytecodealliance#9964)

* Enable `unsafe-attr-outside-unsafe` 2024 edition lint

This commit enables the `unsafe-attr-outside-unsafe` lint in rustc used
in transitioning to the 2024 edition. This requires that the
`#[no_mangle]` attribute is replaced in favor of `#[unsafe(no_mangle)]`.
This mostly affects the C API of wasmtime and most of the changes here
are a simple search/replace.

* Another attribute update

* Fix command adapter build

Author: alexcrichton

Cargo.toml

@@ -183,6 +183,7 @@ unused-macro-rules = 'warn'
 # bit too noisy to enable wholesale but some selective items are ones we want to
 # opt-in to.
 keyword_idents_2024 = 'warn'
+unsafe-attr-outside-unsafe = 'warn'
 deprecated-safe-2024 = 'warn'
 rust-2024-guarded-string-incompatible-syntax = 'warn'
 rust-2024-prelude-collisions = 'warn'

crates/bench-api/src/lib.rs

@@ -265,7 +265,7 @@ impl WasmBenchConfig {
 /// that contains the engine's initialized state, and `0` is returned. On
 /// failure, a non-zero status code is returned and `out_bench_ptr` is left
 /// untouched.
-#[no_mangle]
+#[unsafe(no_mangle)]
 pub extern "C" fn wasm_bench_create(
     config: WasmBenchConfig,
     out_bench_ptr: *mut *mut c_void,
@@ -347,7 +347,7 @@ pub extern "C" fn wasm_bench_create(
 }
 
 /// Free the engine state allocated by this library.
-#[no_mangle]
+#[unsafe(no_mangle)]
 pub extern "C" fn wasm_bench_free(state: *mut c_void) {
     assert!(!state.is_null());
     unsafe {
@@ -356,7 +356,7 @@ pub extern "C" fn wasm_bench_free(state: *mut c_void) {
 }
 
 /// Compile the Wasm benchmark module.
-#[no_mangle]
+#[unsafe(no_mangle)]
 pub extern "C" fn wasm_bench_compile(
     state: *mut c_void,
     wasm_bytes: *const u8,
@@ -369,15 +369,15 @@ pub extern "C" fn wasm_bench_compile(
 }
 
 /// Instantiate the Wasm benchmark module.
-#[no_mangle]
+#[unsafe(no_mangle)]
 pub extern "C" fn wasm_bench_instantiate(state: *mut c_void) -> ExitCode {
     let state = unsafe { (state as *mut BenchState).as_mut().unwrap() };
     let result = state.instantiate().context("failed to instantiate");
     to_exit_code(result)
 }
 
 /// Execute the Wasm benchmark module.
-#[no_mangle]
+#[unsafe(no_mangle)]
 pub extern "C" fn wasm_bench_execute(state: *mut c_void) -> ExitCode {
     let state = unsafe { (state as *mut BenchState).as_mut().unwrap() };
     let result = state.execute().context("failed to execute");

crates/c-api-macros/src/lib.rs

@@ -26,7 +26,7 @@ pub fn declare_own(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
 
     (quote! {
         #[doc = #docs]
-        #[no_mangle]
+        #[unsafe(no_mangle)]
         pub extern fn #delete(_: Box<#ty>) {}
     })
     .into()
@@ -48,7 +48,7 @@ pub fn declare_ty(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
         wasmtime_c_api_macros::declare_own!(#ty);
 
         #[doc = #docs]
-        #[no_mangle]
+        #[unsafe(no_mangle)]
         pub extern fn #copy(src: &#ty) -> Box<#ty> {
             Box::new(src.clone())
         }
@@ -96,27 +96,27 @@ pub fn declare_ref(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
         wasmtime_c_api_macros::declare_ty!(#ty);
 
         #[doc = #same_docs]
-        #[no_mangle]
+        #[unsafe(no_mangle)]
         pub extern fn #same(_a: &#ty, _b: &#ty) -> bool {
             eprintln!("`{}` is not implemented", stringify!(#same));
             std::process::abort();
         }
 
         #[doc = #get_host_info_docs]
-        #[no_mangle]
+        #[unsafe(no_mangle)]
         pub extern fn #get_host_info(a: &#ty) -> *mut std::os::raw::c_void {
             std::ptr::null_mut()
         }
 
         #[doc = #set_host_info_docs]
-        #[no_mangle]
+        #[unsafe(no_mangle)]
         pub extern fn #set_host_info(a: &#ty, info: *mut std::os::raw::c_void) {
             eprintln!("`{}` is not implemented", stringify!(#set_host_info));
             std::process::abort();
         }
 
         #[doc = #set_host_info_final_docs]
-        #[no_mangle]
+        #[unsafe(no_mangle)]
         pub extern fn #set_host_info_final(
             a: &#ty,
             info: *mut std::os::raw::c_void,
@@ -127,14 +127,14 @@ pub fn declare_ref(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
         }
 
         #[doc = #as_ref_docs]
-        #[no_mangle]
+        #[unsafe(no_mangle)]
         pub extern fn #as_ref(a: &#ty) -> Box<crate::wasm_ref_t> {
             eprintln!("`{}` is not implemented", stringify!(#as_ref));
             std::process::abort();
         }
 
         #[doc = #as_ref_const_docs]
-        #[no_mangle]
+        #[unsafe(no_mangle)]
         pub extern fn #as_ref_const(a: &#ty) -> Box<crate::wasm_ref_t> {
             eprintln!("`{}` is not implemented", stringify!(#as_ref_const));
             std::process::abort();

crates/c-api/src/async.rs

@@ -18,25 +18,25 @@ use crate::{
     WASMTIME_I32,
 };
 
-#[no_mangle]
+#[unsafe(no_mangle)]
 pub extern "C" fn wasmtime_config_async_support_set(c: &mut wasm_config_t, enable: bool) {
     c.config.async_support(enable);
 }
 
-#[no_mangle]
+#[unsafe(no_mangle)]
 pub extern "C" fn wasmtime_config_async_stack_size_set(c: &mut wasm_config_t, size: usize) {
     c.config.async_stack_size(size);
 }
 
-#[no_mangle]
+#[unsafe(no_mangle)]
 pub extern "C" fn wasmtime_context_epoch_deadline_async_yield_and_update(
     mut store: WasmtimeStoreContextMut<'_>,
     delta: u64,
 ) {
     store.epoch_deadline_async_yield_and_update(delta);
 }
 
-#[no_mangle]
+#[unsafe(no_mangle)]
 pub extern "C" fn wasmtime_context_fuel_async_yield_interval(
     mut store: WasmtimeStoreContextMut<'_>,
     interval: Option<NonZeroU64>,
@@ -194,10 +194,10 @@ pub struct wasmtime_call_future_t<'a> {
     underlying: Pin<Box<dyn Future<Output = ()> + 'a>>,
 }
 
-#[no_mangle]
+#[unsafe(no_mangle)]
 pub extern "C" fn wasmtime_call_future_delete(_future: Box<wasmtime_call_future_t>) {}
 
-#[no_mangle]
+#[unsafe(no_mangle)]
 pub extern "C" fn wasmtime_call_future_poll(future: &mut wasmtime_call_future_t) -> bool {
     let w = futures::task::noop_waker_ref();
     match future.underlying.as_mut().poll(&mut Context::from_waker(w)) {
@@ -242,7 +242,7 @@ async fn do_func_call_async(
     }
 }
 
-#[no_mangle]
+#[unsafe(no_mangle)]
 pub unsafe extern "C" fn wasmtime_func_call_async<'a>(
     store: WasmtimeStoreContextMut<'a>,
     func: &'a Func,
@@ -270,7 +270,7 @@ pub unsafe extern "C" fn wasmtime_func_call_async<'a>(
     Box::new(wasmtime_call_future_t { underlying: fut })
 }
 
-#[no_mangle]
+#[unsafe(no_mangle)]
 pub unsafe extern "C" fn wasmtime_linker_define_async_func(
     linker: &mut wasmtime_linker_t,
     module: *const u8,
@@ -308,7 +308,7 @@ async fn do_linker_instantiate_async(
     }
 }
 
-#[no_mangle]
+#[unsafe(no_mangle)]
 pub extern "C" fn wasmtime_linker_instantiate_async<'a>(
     linker: &'a wasmtime_linker_t,
     store: WasmtimeStoreContextMut<'a>,
@@ -342,7 +342,7 @@ async fn do_instance_pre_instantiate_async(
     }
 }
 
-#[no_mangle]
+#[unsafe(no_mangle)]
 pub extern "C" fn wasmtime_instance_pre_instantiate_async<'a>(
     instance_pre: &'a wasmtime_instance_pre_t,
     store: WasmtimeStoreContextMut<'a>,
@@ -438,7 +438,7 @@ unsafe impl StackCreator for CHostStackCreator {
     }
 }
 
-#[no_mangle]
+#[unsafe(no_mangle)]
 pub unsafe extern "C" fn wasmtime_config_host_stack_creator_set(
     c: &mut wasm_config_t,
     creator: &wasmtime_stack_creator_t,