From: Arthur Cohen <[email protected]>
Per Rust's RFC 1861 (https://rust-lang.github.io/rfcs/1861-extern-types.html),
extern types
are FFI-safe types that are dynamically sized, and should thus compile down to
regular empty
types like C's void type. They are to always be used with an indirection, which
means they are
effectively always a regular pointer (not a pointer + metadata like a lot of
pointers in Rust) to
C's void type.
Closes Rust-GCC/gccrs#1922. We eventually need to work on adding checks to
external types, but as
they are currently implemented as types not implementing `Sized`, a lot of
their typechecking
behavior is covered.
gcc/rust/ChangeLog:
* backend/rust-compile-type.cc (TyTyResolveCompile::visit): Change
extern type codegen from
empty struct to the void type node.
---
gcc/rust/backend/rust-compile-type.cc | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/gcc/rust/backend/rust-compile-type.cc
b/gcc/rust/backend/rust-compile-type.cc
index 56f9e942434..4b39a44f11c 100644
--- a/gcc/rust/backend/rust-compile-type.cc
+++ b/gcc/rust/backend/rust-compile-type.cc
@@ -344,7 +344,10 @@ TyTyResolveCompile::visit (const TyTy::ADTType &type)
}
else if (type.get_adt_kind () == TyTy::ADTType::ADTKind::EXTERN)
{
- type_record = Backend::struct_type ({});
+ // Extern types are codegen'd as C's void type. They can only be used
+ // through indirection, so they're effectively always codegen'd as
+ // `void *` types.
+ type_record = void_type_node;
}
else if (!type.is_enum ())
{
--
2.50.1
