Represent friend functions in IR.
This is implemented by resolving friend declarations to their underlying function or function template declaration (discarding friend non-functions) and recursing through the existing function [template] importers.
PiperOrigin-RevId: 463662513
diff --git a/rs_bindings_from_cc/test/golden/friend_functions_rs_api.rs b/rs_bindings_from_cc/test/golden/friend_functions_rs_api.rs
new file mode 100644
index 0000000..b95cbdf
--- /dev/null
+++ b/rs_bindings_from_cc/test/golden/friend_functions_rs_api.rs
@@ -0,0 +1,118 @@
+// Part of the Crubit project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+// Automatically @generated Rust bindings for C++ target
+// //rs_bindings_from_cc/test/golden:friend_functions_cc
+#![rustfmt::skip]
+#![feature(const_ptr_offset_from, custom_inner_attributes)]
+#![allow(non_camel_case_types)]
+#![allow(non_snake_case)]
+#![allow(non_upper_case_globals)]
+#![deny(warnings)]
+
+// Part of the Crubit project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+#[derive(Clone, Copy)]
+#[repr(C)]
+pub struct SomeClass {
+ __non_field_data: [::std::mem::MaybeUninit<u8>; 1],
+}
+forward_declare::unsafe_define!(forward_declare::symbol!("SomeClass"), crate::SomeClass);
+
+impl Default for SomeClass {
+ #[inline(always)]
+ fn default() -> Self {
+ let mut tmp = ::std::mem::MaybeUninit::<Self>::zeroed();
+ unsafe {
+ crate::detail::__rust_thunk___ZN9SomeClassC1Ev(&mut tmp);
+ tmp.assume_init()
+ }
+ }
+}
+
+impl<'b> From<::ctor::RvalueReference<'b, crate::SomeClass>> for SomeClass {
+ #[inline(always)]
+ fn from(__param_0: ::ctor::RvalueReference<'b, crate::SomeClass>) -> Self {
+ let mut tmp = ::std::mem::MaybeUninit::<Self>::zeroed();
+ unsafe {
+ crate::detail::__rust_thunk___ZN9SomeClassC1EOS_(&mut tmp, __param_0);
+ tmp.assume_init()
+ }
+ }
+}
+
+// rs_bindings_from_cc/test/golden/friend_functions.h;l=10
+// Error while generating bindings for item 'SomeClass::operator=':
+// operator= for Unpin types is not yet supported.
+
+// rs_bindings_from_cc/test/golden/friend_functions.h;l=10
+// Error while generating bindings for item 'SomeClass::operator=':
+// operator= for Unpin types is not yet supported.
+
+/// Friend functions that are visible via ADL.
+#[inline(always)]
+pub fn visible_val(__param_0: crate::SomeClass) {
+ unsafe { crate::detail::__rust_thunk___Z11visible_val9SomeClass(__param_0) }
+}
+
+#[inline(always)]
+pub fn visible_ref<'a>(__param_0: &'a mut crate::SomeClass) {
+ unsafe { crate::detail::__rust_thunk___Z11visible_refR9SomeClass(__param_0) }
+}
+
+#[inline(always)]
+pub fn visible_cref<'a>(__param_0: &'a crate::SomeClass) {
+ unsafe { crate::detail::__rust_thunk___Z12visible_crefRK9SomeClass(__param_0) }
+}
+
+#[inline(always)]
+pub fn visible_rref<'a>(__param_0: ::ctor::RvalueReference<'a, crate::SomeClass>) {
+ unsafe { crate::detail::__rust_thunk___Z12visible_rrefO9SomeClass(__param_0) }
+}
+
+// CRUBIT_RS_BINDINGS_FROM_CC_TEST_GOLDEN_FRIEND_FUNCTIONS_H_
+
+mod detail {
+ #[allow(unused_imports)]
+ use super::*;
+ extern "C" {
+ pub(crate) fn __rust_thunk___ZN9SomeClassC1Ev<'a>(
+ __this: &'a mut ::std::mem::MaybeUninit<crate::SomeClass>,
+ );
+ pub(crate) fn __rust_thunk___ZN9SomeClassC1EOS_<'a, 'b>(
+ __this: &'a mut ::std::mem::MaybeUninit<crate::SomeClass>,
+ __param_0: ::ctor::RvalueReference<'b, crate::SomeClass>,
+ );
+ #[link_name = "_Z11visible_val9SomeClass"]
+ pub(crate) fn __rust_thunk___Z11visible_val9SomeClass(__param_0: crate::SomeClass);
+ #[link_name = "_Z11visible_refR9SomeClass"]
+ pub(crate) fn __rust_thunk___Z11visible_refR9SomeClass<'a>(
+ __param_0: &'a mut crate::SomeClass,
+ );
+ #[link_name = "_Z12visible_crefRK9SomeClass"]
+ pub(crate) fn __rust_thunk___Z12visible_crefRK9SomeClass<'a>(
+ __param_0: &'a crate::SomeClass,
+ );
+ #[link_name = "_Z12visible_rrefO9SomeClass"]
+ pub(crate) fn __rust_thunk___Z12visible_rrefO9SomeClass<'a>(
+ __param_0: ::ctor::RvalueReference<'a, crate::SomeClass>,
+ );
+ }
+}
+
+const _: () = assert!(::std::mem::size_of::<Option<&i32>>() == ::std::mem::size_of::<&i32>());
+
+const _: () = assert!(::std::mem::size_of::<crate::SomeClass>() == 1);
+const _: () = assert!(::std::mem::align_of::<crate::SomeClass>() == 1);
+const _: () = {
+ static_assertions::assert_impl_all!(crate::SomeClass: Clone);
+};
+const _: () = {
+ static_assertions::assert_impl_all!(crate::SomeClass: Copy);
+};
+const _: () = {
+ static_assertions::assert_not_impl_any!(crate::SomeClass: Drop);
+};
