Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

Make wasm-bindgen compatible with the standard C ABI #3595

Merged
merged 7 commits into from
Sep 12, 2023
Merged

Make wasm-bindgen compatible with the standard C ABI #3595

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
7 commits
Select commit Hold shift + click to select a range
4b73e0f
Make `wasm-bindgen` compatible with the standard C ABI
Liamolucko Sep 5, 2023
9460acc
Update the guide
Liamolucko Sep 5, 2023
fea9ca9
Fix reference tests
Liamolucko Sep 6, 2023
4b8aecf
Add changelog entry
Liamolucko Sep 7, 2023
600c40c
Add spacing
Liamolucko Sep 7, 2023
c83a290
Mention `WasmAbi` in the changelog
Liamolucko Sep 7, 2023
6078cb3
fix a tiny typo
Liamolucko Sep 12, 2023
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Jump to
Jump to file
Failed to load files.
Diff view
Diff view
11 changes: 11 additions & 0 deletions CHANGELOG.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -70,6 +70,17 @@
When exported constructors return `Self`.
[#3562](https://github.com/rustwasm/wasm-bindgen/pull/3562)

* Made `wasm-bindgen` forwards-compatible with the standard C ABI.
[#3595](https://github.com/rustwasm/wasm-bindgen/pull/3595)
Liamolucko marked this conversation as resolved.
Show resolved Hide resolved

* Changed the design of the internal `WasmAbi` trait. Rather than marking a type
which can be passed directly as a parameter/result to/from JS, it now lets
types specify how they can be split into / recreated from multiple primitive
types which are then passed to/from JS.
`WasmPrimitive` now serves the old function of `WasmAbi`, minus allowing
`#[repr(C)]` types.
[#3595](https://github.com/rustwasm/wasm-bindgen/pull/3595)

### Fixed

* Fixed bindings and comments for `Atomics.wait`.
Expand Down
124 changes: 86 additions & 38 deletions crates/backend/src/codegen.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -3,6 +3,7 @@ use crate::encode;
use crate::Diagnostic;
use once_cell::sync::Lazy;
use proc_macro2::{Ident, Literal, Span, TokenStream};
use quote::format_ident;
use quote::quote_spanned;
use quote::{quote, ToTokens};
use std::collections::{HashMap, HashSet};
Expand Down Expand Up @@ -142,15 +143,15 @@ impl TryToTokens for ast::LinkToModule {
let link_function_name = self.0.link_function_name(0);
let name = Ident::new(&link_function_name, Span::call_site());
let wasm_bindgen = &self.0.wasm_bindgen;
let abi_ret = quote! { <std::string::String as #wasm_bindgen::convert::FromWasmAbi>::Abi };
let abi_ret = quote! { #wasm_bindgen::convert::WasmRet<<std::string::String as #wasm_bindgen::convert::FromWasmAbi>::Abi> };
let extern_fn = extern_fn(&name, &[], &[], &[], abi_ret);
(quote! {
{
#program
#extern_fn

unsafe {
<std::string::String as #wasm_bindgen::convert::FromWasmAbi>::from_abi(#name())
<std::string::String as #wasm_bindgen::convert::FromWasmAbi>::from_abi(#name().join())
}
}
})
Expand Down Expand Up @@ -401,7 +402,7 @@ impl ToTokens for ast::StructField {
#[cfg_attr(all(target_arch = "wasm32", not(any(target_os = "emscripten", target_os = "wasi"))), no_mangle)]
#[doc(hidden)]
pub unsafe extern "C" fn #getter(js: u32)
-> <#ty as #wasm_bindgen::convert::IntoWasmAbi>::Abi
-> #wasm_bindgen::convert::WasmRet<<#ty as #wasm_bindgen::convert::IntoWasmAbi>::Abi>
{
use #wasm_bindgen::__rt::{WasmRefCell, assert_not_null};
use #wasm_bindgen::convert::IntoWasmAbi;
Expand All @@ -412,7 +413,7 @@ impl ToTokens for ast::StructField {
let js = js as *mut WasmRefCell<#struct_name>;
assert_not_null(js);
let val = #val;
<#ty as IntoWasmAbi>::into_abi(val)
<#ty as IntoWasmAbi>::into_abi(val).into()
}
};
})
Expand All @@ -432,6 +433,9 @@ impl ToTokens for ast::StructField {
return;
}

let abi = quote! { <#ty as #wasm_bindgen::convert::FromWasmAbi>::Abi };
let (args, names) = splat(wasm_bindgen, &Ident::new("val", rust_name.span()), &abi);

(quote! {
#[cfg(all(target_arch = "wasm32", not(any(target_os = "emscripten", target_os = "wasi"))))]
#[automatically_derived]
Expand All @@ -440,13 +444,14 @@ impl ToTokens for ast::StructField {
#[doc(hidden)]
pub unsafe extern "C" fn #setter(
js: u32,
val: <#ty as #wasm_bindgen::convert::FromWasmAbi>::Abi,
#(#args,)*
) {
use #wasm_bindgen::__rt::{WasmRefCell, assert_not_null};
use #wasm_bindgen::convert::FromWasmAbi;

let js = js as *mut WasmRefCell<#struct_name>;
assert_not_null(js);
let val = <#abi as #wasm_bindgen::convert::WasmAbi>::join(#(#names),*);
let val = <#ty as FromWasmAbi>::from_abi(val);
(*js).borrow_mut().#rust_name = val;
}
Expand Down Expand Up @@ -525,52 +530,61 @@ impl TryToTokens for ast::Export {
elem,
..
}) => {
args.push(quote! {
#ident: <#elem as #wasm_bindgen::convert::RefMutFromWasmAbi>::Abi
});
let abi = quote! { <#elem as #wasm_bindgen::convert::RefMutFromWasmAbi>::Abi };
let (prim_args, prim_names) = splat(wasm_bindgen, &ident, &abi);
args.extend(prim_args);
arg_conversions.push(quote! {
let mut #ident = unsafe {
<#elem as #wasm_bindgen::convert::RefMutFromWasmAbi>
::ref_mut_from_abi(#ident)
::ref_mut_from_abi(
<#abi as #wasm_bindgen::convert::WasmAbi>::join(#(#prim_names),*)
)
};
let #ident = &mut *#ident;
});
}
syn::Type::Reference(syn::TypeReference { elem, .. }) => {
if self.function.r#async {
args.push(quote! {
#ident: <#elem as #wasm_bindgen::convert::LongRefFromWasmAbi>::Abi
});
let abi =
quote! { <#elem as #wasm_bindgen::convert::LongRefFromWasmAbi>::Abi };
let (prim_args, prim_names) = splat(wasm_bindgen, &ident, &abi);
args.extend(prim_args);
arg_conversions.push(quote! {
let #ident = unsafe {
<#elem as #wasm_bindgen::convert::LongRefFromWasmAbi>
::long_ref_from_abi(#ident)
::long_ref_from_abi(
<#abi as #wasm_bindgen::convert::WasmAbi>::join(#(#prim_names),*)
)
};
let #ident = <<#elem as #wasm_bindgen::convert::LongRefFromWasmAbi>
::Anchor as core::borrow::Borrow<#elem>>
::borrow(&#ident);
});
} else {
args.push(quote! {
#ident: <#elem as #wasm_bindgen::convert::RefFromWasmAbi>::Abi
});
let abi = quote! { <#elem as #wasm_bindgen::convert::RefFromWasmAbi>::Abi };
let (prim_args, prim_names) = splat(wasm_bindgen, &ident, &abi);
args.extend(prim_args);
arg_conversions.push(quote! {
let #ident = unsafe {
<#elem as #wasm_bindgen::convert::RefFromWasmAbi>
::ref_from_abi(#ident)
::ref_from_abi(
<#abi as #wasm_bindgen::convert::WasmAbi>::join(#(#prim_names),*)
)
};
let #ident = &*#ident;
});
}
}
_ => {
args.push(quote! {
#ident: <#ty as #wasm_bindgen::convert::FromWasmAbi>::Abi
});
let abi = quote! { <#ty as #wasm_bindgen::convert::FromWasmAbi>::Abi };
let (prim_args, prim_names) = splat(wasm_bindgen, &ident, &abi);
args.extend(prim_args);
arg_conversions.push(quote! {
let #ident = unsafe {
<#ty as #wasm_bindgen::convert::FromWasmAbi>
::from_abi(#ident)
::from_abi(
<#abi as #wasm_bindgen::convert::WasmAbi>::join(#(#prim_names),*)
)
};
});
}
Expand Down Expand Up @@ -642,7 +656,7 @@ impl TryToTokens for ast::Export {
}

let projection = quote! { <#ret_ty as #wasm_bindgen::convert::ReturnWasmAbi> };
let convert_ret = quote! { #projection::return_abi(#ret) };
let convert_ret = quote! { #projection::return_abi(#ret).into() };
let describe_ret = quote! {
<#ret_ty as WasmDescribe>::describe();
<#inner_ret_ty as WasmDescribe>::describe();
Expand All @@ -664,7 +678,7 @@ impl TryToTokens for ast::Export {
all(target_arch = "wasm32", not(any(target_os = "emscripten", target_os = "wasi"))),
export_name = #export_name,
)]
pub unsafe extern "C" fn #generated_name(#(#args),*) -> #projection::Abi {
pub unsafe extern "C" fn #generated_name(#(#args),*) -> #wasm_bindgen::convert::WasmRet<#projection::Abi> {
#start_check

let #ret = #call;
Expand Down Expand Up @@ -1147,10 +1161,11 @@ impl TryToTokens for ast::ImportFunction {
),
};

abi_argument_names.push(name.clone());
abi_arguments.push(quote! {
#name: <#ty as #wasm_bindgen::convert::IntoWasmAbi>::Abi
});
let abi = quote! { <#ty as #wasm_bindgen::convert::IntoWasmAbi>::Abi };
let (prim_args, prim_names) = splat(wasm_bindgen, &name, &abi);
abi_arguments.extend(prim_args);
abi_argument_names.extend(prim_names.iter().cloned());

let var = if i == 0 && is_method {
quote! { self }
} else {
Expand All @@ -1160,6 +1175,7 @@ impl TryToTokens for ast::ImportFunction {
arg_conversions.push(quote! {
let #name = <#ty as #wasm_bindgen::convert::IntoWasmAbi>
::into_abi(#var);
let (#(#prim_names),*) = <#abi as #wasm_bindgen::convert::WasmAbi>::split(#name);
});
}
let abi_ret;
Expand All @@ -1173,12 +1189,13 @@ impl TryToTokens for ast::ImportFunction {
}
Some(ref ty) => {
if self.function.r#async {
abi_ret =
quote! { <js_sys::Promise as #wasm_bindgen::convert::FromWasmAbi>::Abi };
abi_ret = quote! {
#wasm_bindgen::convert::WasmRet<<js_sys::Promise as #wasm_bindgen::convert::FromWasmAbi>::Abi>
};
let future = quote! {
#wasm_bindgen_futures::JsFuture::from(
<js_sys::Promise as #wasm_bindgen::convert::FromWasmAbi>
::from_abi(#ret_ident)
::from_abi(#ret_ident.join())
).await
};
convert_ret = if self.catch {
Expand All @@ -1188,22 +1205,23 @@ impl TryToTokens for ast::ImportFunction {
};
} else {
abi_ret = quote! {
<#ty as #wasm_bindgen::convert::FromWasmAbi>::Abi
#wasm_bindgen::convert::WasmRet<<#ty as #wasm_bindgen::convert::FromWasmAbi>::Abi>
};
convert_ret = quote! {
<#ty as #wasm_bindgen::convert::FromWasmAbi>
::from_abi(#ret_ident)
::from_abi(#ret_ident.join())
};
}
}
None => {
if self.function.r#async {
abi_ret =
quote! { <js_sys::Promise as #wasm_bindgen::convert::FromWasmAbi>::Abi };
abi_ret = quote! {
#wasm_bindgen::convert::WasmRet<<js_sys::Promise as #wasm_bindgen::convert::FromWasmAbi>::Abi>
};
let future = quote! {
#wasm_bindgen_futures::JsFuture::from(
<js_sys::Promise as #wasm_bindgen::convert::FromWasmAbi>
::from_abi(#ret_ident)
::from_abi(#ret_ident.join())
).await
};
convert_ret = if self.catch {
Expand Down Expand Up @@ -1421,23 +1439,27 @@ impl ToTokens for ast::ImportStatic {
let shim_name = &self.shim;
let vis = &self.vis;
let wasm_bindgen = &self.wasm_bindgen;

let abi_ret = quote! {
#wasm_bindgen::convert::WasmRet<<#ty as #wasm_bindgen::convert::FromWasmAbi>::Abi>
};
(quote! {
#[automatically_derived]
#vis static #name: #wasm_bindgen::JsStatic<#ty> = {
fn init() -> #ty {
#[link(wasm_import_module = "__wbindgen_placeholder__")]
#[cfg(all(target_arch = "wasm32", not(any(target_os = "emscripten", target_os = "wasi"))))]
extern "C" {
fn #shim_name() -> <#ty as #wasm_bindgen::convert::FromWasmAbi>::Abi;
fn #shim_name() -> #abi_ret;
}

#[cfg(not(all(target_arch = "wasm32", not(any(target_os = "emscripten", target_os = "wasi")))))]
unsafe fn #shim_name() -> <#ty as wasm_bindgen::convert::FromWasmAbi>::Abi {
unsafe fn #shim_name() -> #abi_ret {
panic!("cannot access imported statics on non-wasm targets")
}

unsafe {
<#ty as #wasm_bindgen::convert::FromWasmAbi>::from_abi(#shim_name())
<#ty as #wasm_bindgen::convert::FromWasmAbi>::from_abi(#shim_name().join())
}
}
thread_local!(static _VAL: #ty = init(););
Expand Down Expand Up @@ -1540,6 +1562,32 @@ fn extern_fn(
}
}

/// Splats an argument with the given name and ABI type into 4 arguments, one
/// for each primitive that the ABI type splits into.
///
/// Returns an `(args, names)` pair, where `args` is the list of arguments to
/// be inserted into the function signature, and `names` is a list of the names
/// of those arguments.
fn splat(
wasm_bindgen: &syn::Path,
name: &Ident,
abi: &TokenStream,
) -> (Vec<TokenStream>, Vec<Ident>) {
let mut args = Vec::new();
let mut names = Vec::new();

for n in 1..=4 {
let arg_name = format_ident!("{name}_{n}");
let prim_name = format_ident!("Prim{n}");
args.push(quote! {
#arg_name: <#abi as #wasm_bindgen::convert::WasmAbi>::#prim_name
});
names.push(arg_name);
}

(args, names)
}

/// Converts `span` into a stream of tokens, and attempts to ensure that `input`
/// has all the appropriate span information so errors in it point to `span`.
fn respan(input: TokenStream, span: &dyn ToTokens) -> TokenStream {
Expand Down
4 changes: 2 additions & 2 deletions crates/cli/tests/reference/anyref-import-catch.wat
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -5,8 +5,8 @@
(type (;3;) (func (param i32) (result i32)))
(import "./reference_test_bg.js" "__wbindgen_init_externref_table" (func (;0;) (type 0)))
(func $__wbindgen_exn_store (;1;) (type 2) (param i32))
(func $__externref_table_dealloc (;2;) (type 2) (param i32))
(func $exported (;3;) (type 2) (param i32))
(func $exported (;2;) (type 2) (param i32))
(func $__externref_table_dealloc (;3;) (type 2) (param i32))
(func $__externref_table_alloc (;4;) (type 1) (result i32))
(func $__wbindgen_add_to_stack_pointer (;5;) (type 3) (param i32) (result i32))
(table (;0;) 128 externref)
Expand Down
4 changes: 2 additions & 2 deletions crates/cli/tests/reference/builder.wat
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,8 +1,8 @@
(module
(type (;0;) (func (result i32)))
(type (;1;) (func (param i32)))
(func $__wbg_classbuilder_free (;0;) (type 1) (param i32))
(func $classbuilder_builder (;1;) (type 0) (result i32))
(func $classbuilder_builder (;0;) (type 0) (result i32))
(func $__wbg_classbuilder_free (;1;) (type 1) (param i32))
(memory (;0;) 17)
(export "memory" (memory 0))
(export "__wbg_classbuilder_free" (func $__wbg_classbuilder_free))
Expand Down
4 changes: 2 additions & 2 deletions crates/cli/tests/reference/constructor.wat
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,8 +1,8 @@
(module
(type (;0;) (func (result i32)))
(type (;1;) (func (param i32)))
(func $__wbg_classconstructor_free (;0;) (type 1) (param i32))
(func $classconstructor_new (;1;) (type 0) (result i32))
(func $classconstructor_new (;0;) (type 0) (result i32))
(func $__wbg_classconstructor_free (;1;) (type 1) (param i32))
(memory (;0;) 17)
(export "memory" (memory 0))
(export "__wbg_classconstructor_free" (func $__wbg_classconstructor_free))
Expand Down