Retain unsafe in imports (rustwasm#3302)

crates/backend/src/ast.rs

@@ -301,6 +301,8 @@ pub struct Function {
     pub rust_attrs: Vec<syn::Attribute>,
     /// The visibility of this function in Rust
     pub rust_vis: syn::Visibility,
+    /// Whether this is an `unsafe` function
+    pub r#unsafe: bool,
     /// Whether this is an `async` function
     pub r#async: bool,
     /// Whether to generate a typescript definition for this function

crates/backend/src/codegen.rs

@@ -1178,6 +1178,11 @@ impl TryToTokens for ast::ImportFunction {
             &self.rust_name,
         );
 
+        let maybe_unsafe = if self.function.r#unsafe {
+            Some(quote! {unsafe})
+        } else {
+            None
+        };
         let maybe_async = if self.function.r#async {
             Some(quote! {async})
         } else {
@@ -1190,7 +1195,7 @@ impl TryToTokens for ast::ImportFunction {
             #[allow(clippy::all, clippy::nursery, clippy::pedantic, clippy::restriction)]
             #(#attrs)*
             #[doc = #doc_comment]
-            #vis #maybe_async fn #rust_name(#me #(#arguments),*) #ret {
+            #vis #maybe_async #maybe_unsafe fn #rust_name(#me #(#arguments),*) #ret {
                 #extern_fn
 
                 unsafe {

crates/macro-support/src/parser.rs

@@ -909,6 +909,7 @@ fn function_from_decl(
             ret,
             rust_attrs: attrs,
             rust_vis: vis,
+            r#unsafe: sig.unsafety.is_some(),
             r#async: sig.asyncness.is_some(),
             generate_typescript: opts.skip_typescript().is_none(),
             variadic: opts.variadic().is_some(),