Improve ABI conversion (#1746)

* Abi docs improvements * Change to using MaybeUninit when convering from abi * Run codegen * Initialize result__ to zero because we may read it even on error * Rerun codegen * Remove need for ManuallyDrop around non-blittable types * Run codegen once again * Fix issue with non-blittable ABI types * Revert manually drop change * Final weaks to the docs * Add clarifying note about no need for AddRef
microsoft · May 11, 2022 · 8281cc9 · 8281cc9
1 parent c178210
commit 8281cc9
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Showing 534 changed files with 121,582 additions and 121,493 deletions.
diff --git a/crates/libs/bindgen/src/functions.rs b/crates/libs/bindgen/src/functions.rs
@@ -172,8 +172,8 @@ fn gen_win_function(def: &MethodDef, gen: &Gen) -> TokenStream {
                         extern "system" {
                             fn #name(#(#abi_params),*) #abi_return_type;
                         }
-                        let mut result__: #abi_return_type_tokens = ::core::mem::zeroed();
-                        #name(#args ::core::mem::transmute(&mut result__)).from_abi::<#return_type_tokens>(result__)
+                        let mut result__ = ::core::mem::MaybeUninit::<#abi_return_type_tokens>::zeroed();
+                        #name(#args ::core::mem::transmute(result__.as_mut_ptr())).from_abi::<#return_type_tokens>(result__)
                     }
                     #[cfg(not(windows))]
                     unimplemented!("Unsupported target OS");

diff --git a/crates/libs/bindgen/src/methods.rs b/crates/libs/bindgen/src/methods.rs
@@ -37,9 +37,9 @@ pub fn gen_winrt_method(def: &TypeDef, kind: InterfaceKind, method: &MethodDef,
     let return_arg = if let Some(return_type) = &signature.return_type {
         if return_type.is_winrt_array() {
             let return_type = gen_element_name(return_type, gen);
-            quote! { ::windows::core::Array::<#return_type>::set_abi_len(&mut result__), &mut result__ as *mut _ as _ }
+            quote! { ::windows::core::Array::<#return_type>::set_abi_len(result__.assume_init_mut()), result__.as_mut_ptr() as *mut _ as _ }
         } else {
-            quote! { &mut result__ }
+            quote! { result__.as_mut_ptr() }
         }
     } else {
         quote! {}
@@ -56,9 +56,9 @@ pub fn gen_winrt_method(def: &TypeDef, kind: InterfaceKind, method: &MethodDef,
         if return_type.is_winrt_array() {
             (
                 quote! {
-                    let mut result__: #return_type_tokens = ::core::mem::zeroed();
+                    let mut result__ = ::core::mem::MaybeUninit::<#return_type_tokens>::zeroed();
                     (::windows::core::Interface::vtable(this).#vname)(::windows::core::Interface::as_raw(this), #(#args,)* #composable_args #return_arg)
-                        .and_then(|| result__ )
+                        .and_then(|| result__.assume_init() )
                 },
                 quote! {},
             )
@@ -68,14 +68,14 @@ pub fn gen_winrt_method(def: &TypeDef, kind: InterfaceKind, method: &MethodDef,
 
             (
                 quote! {
-                    let mut result__: #abi_type_name = ::core::mem::zeroed();
-                        (::windows::core::Interface::vtable(this).#vname)(::windows::core::Interface::as_raw(this), #args #composable_args #return_arg)
-                            .from_abi::<#return_type_tokens>(result__ )
+                    let mut result__ = ::core::mem::MaybeUninit::<#abi_type_name>::zeroed();
+                    (::windows::core::Interface::vtable(this).#vname)(::windows::core::Interface::as_raw(this), #args #composable_args #return_arg)
+                        .from_abi::<#return_type_tokens>(result__)
                 },
                 quote! {
-                    let mut result__: #abi_type_name = ::core::mem::zeroed();
-                        (::windows::core::Interface::vtable(this).#vname)(::windows::core::Interface::as_raw(this), #args ::core::ptr::null_mut(), &mut ::core::option::Option::<::windows::core::IInspectable>::None as *mut _ as _, #return_arg)
-                            .from_abi::<#return_type_tokens>(result__ )
+                    let mut result__ = ::core::mem::MaybeUninit::<#abi_type_name>::zeroed();
+                    (::windows::core::Interface::vtable(this).#vname)(::windows::core::Interface::as_raw(this), #args ::core::ptr::null_mut(), &mut ::core::option::Option::<::windows::core::IInspectable>::None as *mut _ as _, #return_arg)
+                        .from_abi::<#return_type_tokens>(result__)
                 },
             )
         }
@@ -201,8 +201,8 @@ pub fn gen_com_method(def: &TypeDef, kind: InterfaceKind, method: &MethodDef, me
                 #doc
                 #features
                 pub unsafe fn #name<#constraints>(&self, #params) -> ::windows::core::Result<#return_type_tokens> {
-                    let mut result__: #abi_return_type_tokens = ::core::mem::zeroed();
-                    (::windows::core::Interface::vtable(self)#bases.#vname)(::windows::core::Interface::as_raw(self), #args ::core::mem::transmute(&mut result__))
+                    let mut result__ = ::core::mem::MaybeUninit::<#abi_return_type_tokens>::zeroed();
+                    (::windows::core::Interface::vtable(self)#bases.#vname)(::windows::core::Interface::as_raw(self), #args ::core::mem::transmute(result__.as_mut_ptr()))
                     .from_abi::<#return_type_tokens>(result__ )
                 }
             }

diff --git a/crates/libs/bindgen/src/structs.rs b/crates/libs/bindgen/src/structs.rs
@@ -115,7 +115,6 @@ fn gen_windows_traits(def: &TypeDef, name: &TokenStream, cfg: &Cfg, gen: &Gen) -
         } else {
             quote! { ::core::mem::ManuallyDrop<Self> }
         };
-
         let features = gen.cfg(cfg);
 
         let mut tokens = quote! {