Refactoring `format_thunk_decl/impl` to take `FnSig`.
Before this CL these functions would call `get_fn_sig`, but this doesn't
work well for default methods provided by a trait (such as
`Clone::clone_from`), because the function signature of such methods
needs to be modified by substituting `self_ty` in place of `Self`.
This CL also changes `format_thunk_impl` to take `fn_def_id: DefId`
instead of `LocalDefId`, because methods provided by a trait (and the
trait definition) may come from a different trait.
PiperOrigin-RevId: 540678214
diff --git a/cc_bindings_from_rs/bindings.rs b/cc_bindings_from_rs/bindings.rs
index 5e70327..dac887a 100644
--- a/cc_bindings_from_rs/bindings.rs
+++ b/cc_bindings_from_rs/bindings.rs
@@ -738,15 +738,15 @@
/// Formats a C++ function declaration of a thunk that wraps a Rust function
/// identified by `fn_def_id`. `format_thunk_impl` may panic if `fn_def_id`
/// doesn't identify a function.
-fn format_thunk_decl(
- input: &Input,
- fn_def_id: LocalDefId,
+fn format_thunk_decl<'tcx>(
+ input: &Input<'tcx>,
+ fn_def_id: DefId,
+ sig: &ty::FnSig<'tcx>,
thunk_name: &TokenStream,
) -> Result<CcSnippet> {
let tcx = input.tcx;
let mut prereqs = CcPrerequisites::default();
- let sig = get_fn_sig(tcx, fn_def_id);
let main_api_ret_type = format_ret_ty_for_cc(input, &sig)?.into_tokens(&mut prereqs);
let mut thunk_params = {
@@ -762,7 +762,7 @@
// Rust thunk will move a value via memcpy - we need to `ensure` that
// invoking the C++ destructor (on the moved-away value) is safe.
ensure!(
- !ty.needs_drop(tcx, tcx.param_env(fn_def_id.to_def_id())),
+ !ty.needs_drop(tcx, tcx.param_env(fn_def_id)),
"Only trivially-movable and trivially-destructible types \
may be passed by value over the FFI boundary"
);
@@ -801,13 +801,13 @@
/// - `::crate_name::some_module::SomeStruct::method`
/// - `<::create_name::some_module::SomeStruct as
/// ::core::default::Default>::default`
-fn format_thunk_impl(
- tcx: TyCtxt,
- fn_def_id: LocalDefId,
+fn format_thunk_impl<'tcx>(
+ tcx: TyCtxt<'tcx>,
+ fn_def_id: DefId,
+ sig: &ty::FnSig<'tcx>,
thunk_name: &str,
fully_qualified_fn_name: TokenStream,
) -> Result<TokenStream> {
- let sig = get_fn_sig(tcx, fn_def_id);
let param_names_and_types: Vec<(Ident, Ty)> = {
let param_names = tcx.fn_arg_names(fn_def_id).iter().enumerate().map(|(i, name)| {
if name.as_str().is_empty() {
@@ -1086,7 +1086,7 @@
let mut prereqs = main_api_prereqs;
let thunk_decl =
- format_thunk_decl(input, local_def_id, &thunk_name)?.into_tokens(&mut prereqs);
+ format_thunk_decl(input, def_id, &sig, &thunk_name)?.into_tokens(&mut prereqs);
let mut thunk_args = params
.iter()
@@ -1138,7 +1138,7 @@
quote! { #struct_name :: #fn_name }
}
};
- format_thunk_impl(tcx, local_def_id, &thunk_name, fully_qualified_fn_name)?
+ format_thunk_impl(tcx, def_id, &sig, &thunk_name, fully_qualified_fn_name)?
};
Ok(ApiSnippets { main_api, cc_details, rs_details })
}
@@ -1602,11 +1602,12 @@
inline #cc_struct_name(); __NEWLINE__ __NEWLINE__
});
let fn_def_id = trait_impl.items[0].id.owner_id.def_id;
+ let sig = get_fn_sig(tcx, fn_def_id);
let thunk_name = get_thunk_name(get_symbol_name(tcx, fn_def_id)?);
let cc_details = {
let thunk_name = format_cc_ident(&thunk_name)?;
let CcSnippet { tokens: thunk_decl, prereqs } =
- format_thunk_decl(input, fn_def_id, &thunk_name)?;
+ format_thunk_decl(input, fn_def_id.to_def_id(), &sig, &thunk_name)?;
let tokens = quote! {
#thunk_decl
#cc_struct_name::#cc_struct_name() {
@@ -1619,7 +1620,7 @@
let struct_name = &core.rs_fully_qualified_name;
let fully_qualified_fn_name =
quote! { <#struct_name as ::core::default::Default>::default };
- format_thunk_impl(tcx, fn_def_id, &thunk_name, fully_qualified_fn_name)?
+ format_thunk_impl(tcx, fn_def_id.to_def_id(), &sig, &thunk_name, fully_qualified_fn_name)?
};
Ok(ApiSnippets { main_api, cc_details, rs_details })
}
