Add a number of #[inline] annotation through crates

Adding `#[inline]` will typically improve codegen for optimized builds
without LTO (so far the majority in practice) by allowing functions that
otherwise couldn't be inlined across codegen units to get inlined
across codegen units.

Right now `wasm-bindgen` has a lot of functions that are very small and
delegate to other functions, but aren't otherwise candidates for
inlining because they're concrete.

I was poking around in release-mode wasm recently and noticed an
alarming number of functions for tiny pieces of functionality, which
motivates this patch!

crates/backend/src/codegen.rs

@@ -546,22 +546,26 @@ impl ToTokens for ast::ImportType {
                 impl IntoWasmAbi for #rust_name {
                     type Abi = <JsValue as IntoWasmAbi>::Abi;
 
+                    #[inline]
                     fn into_abi(self, extra: &mut Stack) -> Self::Abi {
                         self.obj.into_abi(extra)
                     }
                 }
 
                 impl OptionIntoWasmAbi for #rust_name {
+                    #[inline]
                     fn none() -> Self::Abi { 0 }
                 }
 
                 impl<'a> OptionIntoWasmAbi for &'a #rust_name {
+                    #[inline]
                     fn none() -> Self::Abi { 0 }
                 }
 
                 impl FromWasmAbi for #rust_name {
                     type Abi = <JsValue as FromWasmAbi>::Abi;
 
+                    #[inline]
                     unsafe fn from_abi(js: Self::Abi, extra: &mut Stack) -> Self {
                         #rust_name {
                             obj: JsValue::from_abi(js, extra),
@@ -570,12 +574,14 @@ impl ToTokens for ast::ImportType {
                 }
 
                 impl OptionFromWasmAbi for #rust_name {
+                    #[inline]
                     fn is_none(abi: &Self::Abi) -> bool { *abi == 0 }
                 }
 
                 impl<'a> IntoWasmAbi for &'a #rust_name {
                     type Abi = <&'a JsValue as IntoWasmAbi>::Abi;
 
+                    #[inline]
                     fn into_abi(self, extra: &mut Stack) -> Self::Abi {
                         (&self.obj).into_abi(extra)
                     }
@@ -585,6 +591,7 @@ impl ToTokens for ast::ImportType {
                     type Abi = <JsValue as RefFromWasmAbi>::Abi;
                     type Anchor = ManuallyDrop<#rust_name>;
 
+                    #[inline]
                     unsafe fn ref_from_abi(js: Self::Abi, extra: &mut Stack) -> Self::Anchor {
                         let tmp = <JsValue as RefFromWasmAbi>::ref_from_abi(js, extra);
                         ManuallyDrop::new(#rust_name {
@@ -595,17 +602,20 @@ impl ToTokens for ast::ImportType {
 
                 // TODO: remove this on the next major version
                 impl From<JsValue> for #rust_name {
+                    #[inline]
                     fn from(obj: JsValue) -> #rust_name {
                         #rust_name { obj }
                     }
                 }
 
                 impl AsRef<JsValue> for #rust_name {
+                    #[inline]
                     fn as_ref(&self) -> &JsValue { &self.obj }
                 }
 
 
                 impl From<#rust_name> for JsValue {
+                    #[inline]
                     fn from(obj: #rust_name) -> JsValue {
                         obj.obj
                     }
@@ -630,10 +640,12 @@ impl ToTokens for ast::ImportType {
                         panic!("cannot check instanceof on non-wasm targets");
                     }
 
+                    #[inline]
                     fn unchecked_from_js(val: JsValue) -> Self {
                         #rust_name { obj: val }
                     }
 
+                    #[inline]
                     fn unchecked_from_js_ref(val: &JsValue) -> &Self {
                         // Should be safe because `#rust_name` is a transparent
                         // wrapper around `val`
@@ -648,6 +660,7 @@ impl ToTokens for ast::ImportType {
         for superclass in self.extends.iter() {
             (quote! {
                 impl From<#rust_name> for #superclass {
+                    #[inline]
                     fn from(obj: #rust_name) -> #superclass {
                         use wasm_bindgen::JsCast;
                         #superclass::unchecked_from_js(obj.into())
@@ -655,6 +668,7 @@ impl ToTokens for ast::ImportType {
                 }
 
                 impl AsRef<#superclass> for #rust_name {
+                    #[inline]
                     fn as_ref(&self) -> &#superclass {
                         use wasm_bindgen::JsCast;
                         #superclass::unchecked_from_js_ref(self.as_ref())
@@ -724,6 +738,7 @@ impl ToTokens for ast::ImportEnum {
                 type Abi = <::wasm_bindgen::JsValue as
                     ::wasm_bindgen::convert::IntoWasmAbi>::Abi;
 
+                #[inline]
                 fn into_abi(self, extra: &mut ::wasm_bindgen::convert::Stack) -> Self::Abi {
                     ::wasm_bindgen::JsValue::from(self).into_abi(extra)
                 }
@@ -971,6 +986,7 @@ impl ToTokens for ast::Enum {
             impl ::wasm_bindgen::convert::IntoWasmAbi for #enum_name {
                 type Abi = u32;
 
+                #[inline]
                 fn into_abi(self, _extra: &mut ::wasm_bindgen::convert::Stack) -> u32 {
                     self as u32
                 }
@@ -1135,11 +1151,13 @@ impl ToTokens for ast::Dictionary {
 
                 // interop w/ JsValue
                 impl From<#name> for JsValue {
+                    #[inline]
                     fn from(val: #name) -> JsValue {
                         val.obj.into()
                     }
                 }
                 impl AsRef<JsValue> for #name {
+                    #[inline]
                     fn as_ref(&self) -> &JsValue { self.obj.as_ref() }
                 }
 
@@ -1152,6 +1170,7 @@ impl ToTokens for ast::Dictionary {
 
                 impl IntoWasmAbi for #name {
                     type Abi = <Object as IntoWasmAbi>::Abi;
+                    #[inline]
                     fn into_abi(self, extra: &mut Stack) -> Self::Abi {
                         self.obj.into_abi(extra)
                     }
@@ -1159,6 +1178,7 @@ impl ToTokens for ast::Dictionary {
 
                 impl<'a> IntoWasmAbi for &'a #name {
                     type Abi = <&'a Object as IntoWasmAbi>::Abi;
+                    #[inline]
                     fn into_abi(self, extra: &mut Stack) -> Self::Abi {
                         (&self.obj).into_abi(extra)
                     }
@@ -1166,18 +1186,22 @@ impl ToTokens for ast::Dictionary {
 
                 impl FromWasmAbi for #name {
                     type Abi = <Object as FromWasmAbi>::Abi;
+                    #[inline]
                     unsafe fn from_abi(abi: Self::Abi, extra: &mut Stack) -> Self {
                         #name { obj: Object::from_abi(abi, extra) }
                     }
                 }
 
                 impl OptionIntoWasmAbi for #name {
+                    #[inline]
                     fn none() -> Self::Abi { Object::none() }
                 }
                 impl<'a> OptionIntoWasmAbi for &'a #name {
+                    #[inline]
                     fn none() -> Self::Abi { <&'a Object>::none() }
                 }
                 impl OptionFromWasmAbi for #name {
+                    #[inline]
                     fn is_none(abi: &Self::Abi) -> bool { Object::is_none(abi) }
                 }
 
@@ -1185,6 +1209,7 @@ impl ToTokens for ast::Dictionary {
                     type Abi = <Object as RefFromWasmAbi>::Abi;
                     type Anchor = ManuallyDrop<#name>;
 
+                    #[inline]
                     unsafe fn ref_from_abi(js: Self::Abi, extra: &mut Stack) -> Self::Anchor {
                         let tmp = <Object as RefFromWasmAbi>::ref_from_abi(js, extra);
                         ManuallyDrop::new(#name {
@@ -1194,14 +1219,17 @@ impl ToTokens for ast::Dictionary {
                 }
 
                 impl JsCast for #name {
+                    #[inline]
                     fn instanceof(val: &JsValue) -> bool {
                         Object::instanceof(val)
                     }
 
+                    #[inline]
                     fn unchecked_from_js(val: JsValue) -> Self {
                         #name { obj: Object::unchecked_from_js(val) }
                     }
 
+                    #[inline]
                     fn unchecked_from_js_ref(val: &JsValue) -> &Self {
                         unsafe { &*(val as *const JsValue as *const #name) }
                     }

src/closure.rs

@@ -327,6 +327,7 @@ macro_rules! doit {
                 <&Self>::describe();
             }
 
+            #[inline]
             fn invoke_fn() -> u32 {
                 #[allow(non_snake_case)]
                 unsafe extern fn invoke<$($var: FromWasmAbi,)* R: ReturnWasmAbi>(
@@ -354,6 +355,7 @@ macro_rules! doit {
                 invoke::<$($var,)* R> as u32
             }
 
+            #[inline]
             fn destroy_fn() -> u32 {
                 unsafe extern fn destroy<$($var: FromWasmAbi,)* R: ReturnWasmAbi>(
                     a: usize,
@@ -376,6 +378,7 @@ macro_rules! doit {
                 <&mut Self>::describe();
             }
 
+            #[inline]
             fn invoke_fn() -> u32 {
                 #[allow(non_snake_case)]
                 unsafe extern fn invoke<$($var: FromWasmAbi,)* R: ReturnWasmAbi>(
@@ -404,6 +407,7 @@ macro_rules! doit {
                 invoke::<$($var,)* R> as u32
             }
 
+            #[inline]
             fn destroy_fn() -> u32 {
                 unsafe extern fn destroy<$($var: FromWasmAbi,)* R: ReturnWasmAbi>(
                     a: usize,

src/convert/impls.rs

@@ -77,6 +77,7 @@ macro_rules! type_wasm_native {
         impl IntoWasmAbi for Option<$t> {
             type Abi = $r;
 
+            #[inline]
             fn into_abi(self, _extra: &mut Stack) -> $r {
                 match self {
                     None => $r {
@@ -94,6 +95,7 @@ macro_rules! type_wasm_native {
         impl FromWasmAbi for Option<$t> {
             type Abi = $r;
 
+            #[inline]
             unsafe fn from_abi(js: $r, _extra: &mut Stack) -> Self {
                 if js.present == 0 {
                     None
@@ -170,6 +172,7 @@ macro_rules! type_64 {
         impl IntoWasmAbi for Option<$t> {
             type Abi = WasmOptional64;
 
+            #[inline]
             fn into_abi(self, _extra: &mut Stack) -> WasmOptional64 {
                 match self {
                     None => WasmOptional64 {
@@ -191,6 +194,7 @@ macro_rules! type_64 {
         impl FromWasmAbi for Option<$t> {
             type Abi = WasmOptional64;
 
+            #[inline]
             unsafe fn from_abi(js: WasmOptional64, _extra: &mut Stack) -> Self {
                 if js.present == 0 {
                     None
@@ -257,6 +261,7 @@ impl FromWasmAbi for char {
 impl IntoWasmAbi for Option<char> {
     type Abi = WasmOptionalU32;
 
+    #[inline]
     fn into_abi(self, _extra: &mut Stack) -> WasmOptionalU32 {
         match self {
             None => WasmOptionalU32 {
@@ -274,6 +279,7 @@ impl IntoWasmAbi for Option<char> {
 impl FromWasmAbi for Option<char> {
     type Abi = WasmOptionalU32;
 
+    #[inline]
     unsafe fn from_abi(js: WasmOptionalU32, _extra: &mut Stack) -> Self {
         if js.present == 0 {
             None

src/lib.rs

@@ -91,6 +91,7 @@ impl JsValue {
     ///
     /// The utf-8 string provided is copied to the JS heap and the string will
     /// be owned by the JS garbage collector.
+    #[inline]
     pub fn from_str(s: &str) -> JsValue {
         unsafe {
             JsValue {
@@ -103,6 +104,7 @@ impl JsValue {
     ///
     /// This function creates a JS value representing a number (a heap
     /// allocated number) and returns a handle to the JS version of it.
+    #[inline]
     pub fn from_f64(n: f64) -> JsValue {
         unsafe {
             JsValue {
@@ -115,22 +117,21 @@ impl JsValue {
     ///
     /// This function creates a JS object representing a boolean (a heap
     /// allocated boolean) and returns a handle to the JS version of it.
+    #[inline]
     pub fn from_bool(b: bool) -> JsValue {
-        JsValue {
+        if b { JsValue::TRUE } else { JsValue::FALSE }
-            idx: if b { JSIDX_TRUE } else { JSIDX_FALSE },
-        }
     }
 
     /// Creates a new JS value representing `undefined`.
+    #[inline]
     pub fn undefined() -> JsValue {
-        JsValue {
+        JsValue::UNDEFINED
-            idx: JSIDX_UNDEFINED,
-        }
     }
 
     /// Creates a new JS value representing `null`.
+    #[inline]
     pub fn null() -> JsValue {
-        JsValue { idx: JSIDX_NULL }
+        JsValue::NULL
     }
 
     /// Creates a new JS symbol with the optional description specified.
@@ -263,50 +264,59 @@ impl JsValue {
     }
 
     /// Tests whether this JS value is `null`
+    #[inline]
     pub fn is_null(&self) -> bool {
         unsafe { __wbindgen_is_null(self.idx) == 1 }
     }
 
     /// Tests whether this JS value is `undefined`
+    #[inline]
     pub fn is_undefined(&self) -> bool {
         unsafe { __wbindgen_is_undefined(self.idx) == 1 }
     }
 
     /// Tests whether the type of this JS value is `symbol`
+    #[inline]
     pub fn is_symbol(&self) -> bool {
         unsafe { __wbindgen_is_symbol(self.idx) == 1 }
     }
 
     /// Tests whether `typeof self == "object" && self !== null`.
+    #[inline]
     pub fn is_object(&self) -> bool {
         unsafe { __wbindgen_is_object(self.idx) == 1 }
     }
 
     /// Tests whether the type of this JS value is `function`.
+    #[inline]
     pub fn is_function(&self) -> bool {
         unsafe { __wbindgen_is_function(self.idx) == 1 }
     }
 }
 
 impl PartialEq for JsValue {
+    #[inline]
     fn eq(&self, other: &JsValue) -> bool {
         unsafe { __wbindgen_jsval_eq(self.idx, other.idx) != 0 }
     }
 }
 
 impl PartialEq<bool> for JsValue {
+    #[inline]
     fn eq(&self, other: &bool) -> bool {
         self.as_bool() == Some(*other)
     }
 }
 
 impl PartialEq<str> for JsValue {
+    #[inline]
     fn eq(&self, other: &str) -> bool {
         *self == JsValue::from_str(other)
     }
 }
 
 impl<'a> PartialEq<&'a str> for JsValue {
+    #[inline]
     fn eq(&self, other: &&'a str) -> bool {
         <JsValue as PartialEq<str>>::eq(self, other)
     }
@@ -314,11 +324,13 @@ impl<'a> PartialEq<&'a str> for JsValue {
 
 if_std! {
     impl PartialEq<String> for JsValue {
+        #[inline]
         fn eq(&self, other: &String) -> bool {
             <JsValue as PartialEq<str>>::eq(self, other)
         }
     }
     impl<'a> PartialEq<&'a String> for JsValue {
+        #[inline]
         fn eq(&self, other: &&'a String) -> bool {
             <JsValue as PartialEq<str>>::eq(self, other)
         }
@@ -326,6 +338,7 @@ if_std! {
 }
 
 impl<'a> From<&'a str> for JsValue {
+        #[inline]
     fn from(s: &'a str) -> JsValue {
         JsValue::from_str(s)
     }
@@ -333,12 +346,14 @@ impl<'a> From<&'a str> for JsValue {
 
 if_std! {
     impl<'a> From<&'a String> for JsValue {
+        #[inline]
         fn from(s: &'a String) -> JsValue {
             JsValue::from_str(s)
         }
     }
 
     impl From<String> for JsValue {
+        #[inline]
         fn from(s: String) -> JsValue {
             JsValue::from_str(&s)
         }
@@ -346,6 +361,7 @@ if_std! {
 }
 
 impl From<bool> for JsValue {
+    #[inline]
     fn from(s: bool) -> JsValue {
         JsValue::from_bool(s)
     }
@@ -355,6 +371,7 @@ impl<'a, T> From<&'a T> for JsValue
 where
     T: JsCast,
 {
+    #[inline]
     fn from(s: &'a T) -> JsValue {
         s.as_ref().clone()
     }
@@ -364,6 +381,7 @@ impl<T> From<Option<T>> for JsValue
 where
     JsValue: From<T>,
 {
+    #[inline]
     fn from(s: Option<T>) -> JsValue {
         match s {
             Some(s) => s.into(),
@@ -374,18 +392,22 @@ where
 
 impl JsCast for JsValue {
     // everything is a `JsValue`!
+    #[inline]
     fn instanceof(_val: &JsValue) -> bool {
         true
     }
+    #[inline]
     fn unchecked_from_js(val: JsValue) -> Self {
         val
     }
+    #[inline]
     fn unchecked_from_js_ref(val: &JsValue) -> &Self {
         val
     }
 }
 
 impl AsRef<JsValue> for JsValue {
+    #[inline]
     fn as_ref(&self) -> &JsValue {
         self
     }
@@ -394,12 +416,14 @@ impl AsRef<JsValue> for JsValue {
 macro_rules! numbers {
     ($($n:ident)*) => ($(
         impl PartialEq<$n> for JsValue {
+            #[inline]
             fn eq(&self, other: &$n) -> bool {
                 self.as_f64() == Some(f64::from(*other))
             }
         }
 
         impl From<$n> for JsValue {
+            #[inline]
             fn from(n: $n) -> JsValue {
                 JsValue::from_f64(n.into())
             }
@@ -495,6 +519,7 @@ impl fmt::Debug for JsValue {
 }
 
 impl Drop for JsValue {
+    #[inline]
     fn drop(&mut self) {
         unsafe {
             // if the first bit is set then this is a stack value, so we for