Support `__crubit::annotate(cpp_name="X")` to rename Rust function names that are C++ reserved keywords.
We keep the thunk name untouched for two reasons:
1. First, it doesn't affect the C++ usage.
2. We can avoid demangling and mangling the thunk name as there is no straight-forward way to replace the name in the thunk name.
PiperOrigin-RevId: 648856269
Change-Id: I3e5c1d2f6822e0a750298c0195efa183162139ba
diff --git a/bazel/llvm.bzl b/bazel/llvm.bzl
index 8312583..12374f3 100644
--- a/bazel/llvm.bzl
+++ b/bazel/llvm.bzl
@@ -53,7 +53,7 @@
executable = False,
)
-LLVM_COMMIT_SHA = "9b8c2fae38bcff0b16d996ee002ff1e989fa23ea"
+LLVM_COMMIT_SHA = "9ceb45cc191628926496bd33b4d52011ed519151"
def llvm_loader_repository_dependencies():
# This *declares* the dependency, but it won't actually be *downloaded* unless it's used.
diff --git a/cc_bindings_from_rs/bindings.rs b/cc_bindings_from_rs/bindings.rs
index 2144142..11ae5c9 100644
--- a/cc_bindings_from_rs/bindings.rs
+++ b/cc_bindings_from_rs/bindings.rs
@@ -1107,10 +1107,13 @@
};
let fully_qualified_fn_name = FullyQualifiedName::new(tcx, def_id);
- let short_fn_name =
+ let unqualified_rust_fn_name =
fully_qualified_fn_name.name.expect("Functions are assumed to always have a name");
- let main_api_fn_name =
- format_cc_ident(short_fn_name.as_str()).context("Error formatting function name")?;
+ let attribute = crubit_attr::get(tcx, def_id).unwrap();
+ let cpp_name = attribute.cpp_name;
+ // The generated C++ function name.
+ let main_api_fn_name = format_cc_ident(cpp_name.unwrap_or(unqualified_rust_fn_name).as_str())
+ .context("Error formatting function name")?;
let mut main_api_prereqs = CcPrerequisites::default();
let main_api_ret_type = format_ret_ty_for_cc(db, &sig)?.into_tokens(&mut main_api_prereqs);
@@ -1190,7 +1193,7 @@
},
None => None,
};
- let needs_definition = short_fn_name.as_str() != thunk_name;
+ let needs_definition = unqualified_rust_fn_name.as_str() != thunk_name;
let main_api_params = params
.iter()
.skip(if method_kind.has_self_param() { 1 } else { 0 })
@@ -1329,7 +1332,7 @@
let fully_qualified_fn_name = match struct_name.as_ref() {
None => fully_qualified_fn_name.format_for_rs(),
Some(struct_name) => {
- let fn_name = make_rs_ident(short_fn_name.as_str());
+ let fn_name = make_rs_ident(unqualified_rust_fn_name.as_str());
let struct_name = struct_name.format_for_rs();
quote! { #struct_name :: #fn_name }
}
@@ -3678,6 +3681,52 @@
});
}
+ #[test]
+ fn test_format_fn_cpp_name() {
+ let test_src = r#"
+ #![feature(register_tool)]
+ #![register_tool(__crubit)]
+
+ #[no_mangle]
+ #[__crubit::annotate(cpp_name="Create")]
+ pub fn foo() {}
+ "#;
+ test_format_item(test_src, "foo", |result| {
+ let result = result.unwrap().unwrap();
+ let main_api = &result.main_api;
+ assert!(main_api.prereqs.is_empty());
+
+ assert_rs_matches!(
+ result.rs_details,
+ quote! {
+ #[no_mangle]
+ extern "C" fn __crubit_thunk_foo() -> () {
+ ::rust_out::foo()
+ }
+ }
+ );
+
+ assert_cc_matches!(
+ main_api.tokens,
+ quote! {
+ void Create();
+ }
+ );
+ assert_cc_matches!(
+ result.cc_details.tokens,
+ quote! {
+ namespace __crubit_internal {
+ extern "C" void __crubit_thunk_foo();
+ }
+ ...
+ inline void Create() {
+ return __crubit_internal::__crubit_thunk_foo();
+ }
+ }
+ );
+ });
+ }
+
/// `test_format_item_fn_const` tests how bindings for an `const fn` are
/// generated.
///
diff --git a/cc_bindings_from_rs/crubit_attr.rs b/cc_bindings_from_rs/crubit_attr.rs
index 33bfc2c..f33e1a5 100644
--- a/cc_bindings_from_rs/crubit_attr.rs
+++ b/cc_bindings_from_rs/crubit_attr.rs
@@ -29,6 +29,18 @@
/// For instance,
/// `#[__crubit::annotate(internal_cc_type="std::basic_string<char>")]`
pub cc_type: Option<Symbol>,
+ // The C++ name of the item. This allows us to rename Rust function names that are
+ // not C++-compatible like `new`.
+ //
+ // For instance,
+ //
+ // ```
+ // #[__crubit::annotate(cpp_name="Create")]
+ // pub fn new() -> i32 {...}
+ // ```
+ //
+ // will rename `new` in Rust to `Create` in C++.
+ pub cpp_name: Option<Symbol>,
}
/// Gets the `#[__crubit::annotate(...)]` attribute(s) applied to a definition.
@@ -40,6 +52,7 @@
// reset in tests. The resulting test failures are very difficult.
let crubit_annotate = &[Symbol::intern("__crubit"), Symbol::intern("annotate")];
let cc_type = Symbol::intern("cc_type");
+ let cpp_name = Symbol::intern("cpp_name");
let mut crubit_attr = CrubitAttr::default();
// A quick note: the parsing logic is unfortunate, but such is life. We don't
@@ -75,6 +88,20 @@
"Unexpected duplicate #[__crubit::annotate(cc_type=...)]"
);
crubit_attr.cc_type = Some(s)
+ } else if arg.path == cpp_name {
+ let MetaItemKind::NameValue(value) = &arg.kind else {
+ bail!("Invalid #[__crubit::annotate(cpp_name=...)] attribute (expected =...)");
+ };
+ let LitKind::Str(s, _raw) = value.kind else {
+ bail!(
+ "Invalid #[__crubit::annotate(cpp_name=...)] attribute (expected =\"...\")"
+ );
+ };
+ ensure!(
+ crubit_attr.cpp_name.is_none(),
+ "Unexpected duplicate #[__crubit::annotate(cpp_name=...)]"
+ );
+ crubit_attr.cpp_name = Some(s);
}
}
}
@@ -126,6 +153,34 @@
}
#[test]
+ fn test_cpp_name() {
+ let test_src = r#"
+ #![feature(register_tool)]
+ #![register_tool(__crubit)]
+ #[__crubit::annotate(cpp_name = "Create")]
+ pub fn new() -> i32 { 0 }
+ "#;
+ run_compiler_for_testing(test_src, |tcx| {
+ let attr = get(tcx, find_def_id_by_name(tcx, "new")).unwrap();
+ assert_eq!(attr.cpp_name.unwrap(), Symbol::intern("Create"));
+ });
+ }
+
+ #[test]
+ fn test_cpp_name_duplicated() {
+ let test_src = r#"
+ #![feature(register_tool)]
+ #![register_tool(__crubit)]
+ #[__crubit::annotate(cpp_name = "Create", cpp_name = "Create2")]
+ pub fn new() -> i32 { 0 }
+ "#;
+ run_compiler_for_testing(test_src, |tcx| {
+ let attr = get(tcx, find_def_id_by_name(tcx, "new"));
+ assert!(attr.is_err());
+ });
+ }
+
+ #[test]
fn test_cc_type_multi() {
let test_src = r#"
#![feature(register_tool)]
