https://gcc.gnu.org/g:2be06e73fcefc311a78bceb15f725b5ae7c6bee6
commit r17-3129-g2be06e73fcefc311a78bceb15f725b5ae7c6bee6 Author: Enes Cevik <[email protected]> Date: Mon Jul 13 13:08:32 2026 +0300 gccrs: lang: Register lang items for alloc crate This patch registers several lang items as stubs to progress towards compiling the 'alloc' crate. - 'oom', 'alloc_layout': Require no specific handling; symbol generation is sufficient. - 'box_free': Full implementation requires a mature drop infrastructure. Registered as a stub for now. - 'drop_in_place': Full implementation requires a mature drop infrastructure. Registered as a stub for now. - 'maybe_uninit': Requires layout engine maturity and niche-filling mechanisms. Registered as a stub. - 'future_trait', 'poll', 'Ready', 'Pending': Registered as stubs due to lack of async support. - 'generator', 'generator_state': Registered as stubs due to lack of generator support. The 'Ready' and 'Pending' lang items are excluded from the new test cases because lang item attributes on enum variants are not currently handled (see Rust-GCC/gccrs#4703). gcc/rust/ChangeLog: * hir/rust-ast-lower-base.cc (warn_if_stub_lang_item): New function. (ASTLoweringBase::handle_lang_item_attribute): Emit a warning if lang item is stub. * util/rust-lang-item.cc (Rust::LangItem::lang_items): Add new lang items to the BiMap. * util/rust-lang-item.h (class LangItem): Add new lang items to Kind enum. gcc/testsuite/ChangeLog: * rust/compile/lang-items-stub.rs: New test. * rust/compile/lang-items-symbol.rs: New test. Signed-off-by: Enes Cevik <[email protected]> Diff: --- gcc/rust/hir/rust-ast-lower-base.cc | 29 ++++++++++++++++++-- gcc/rust/util/rust-lang-item.cc | 12 +++++++++ gcc/rust/util/rust-lang-item.h | 12 +++++++++ gcc/testsuite/rust/compile/lang-items-stub.rs | 36 +++++++++++++++++++++++++ gcc/testsuite/rust/compile/lang-items-symbol.rs | 8 ++++++ 5 files changed, 95 insertions(+), 2 deletions(-) diff --git a/gcc/rust/hir/rust-ast-lower-base.cc b/gcc/rust/hir/rust-ast-lower-base.cc index ffa7a0f39db5..7cbe52af6298 100644 --- a/gcc/rust/hir/rust-ast-lower-base.cc +++ b/gcc/rust/hir/rust-ast-lower-base.cc @@ -853,6 +853,28 @@ ASTLoweringBase::handle_doc_item_attribute (const ItemWrapper &, rust_assert (meta_item); } +static void +warn_if_stub_lang_item (location_t locus, LangItem::Kind kind) +{ + switch (kind) + { + case LangItem::Kind::FUTURE_TRAIT: + case LangItem::Kind::POLL: + case LangItem::Kind::READY: + case LangItem::Kind::PENDING: + case LangItem::Kind::GENERATOR: + case LangItem::Kind::GENERATOR_STATE: + case LangItem::Kind::MAYBE_UNINIT: + case LangItem::Kind::BOX_FREE: + case LangItem::Kind::DROP_IN_PLACE: + rust_warning_at (locus, 0, "%qs is not implemented and has no effect", + LangItem::PrettyString (kind).c_str ()); + break; + default: + break; + } +} + void ASTLoweringBase::handle_lang_item_attribute (const ItemWrapper &item, const AST::Attribute &attr) @@ -863,8 +885,11 @@ ASTLoweringBase::handle_lang_item_attribute (const ItemWrapper &item, auto lang_item_type = LangItem::Parse (*lang_item_type_str); if (lang_item_type) - mappings.insert_lang_item (*lang_item_type, - item.get_mappings ().get_defid ()); + { + mappings.insert_lang_item (*lang_item_type, + item.get_mappings ().get_defid ()); + warn_if_stub_lang_item (attr.get_locus (), *lang_item_type); + } else rust_error_at (attr.get_locus (), "unknown lang item"); } diff --git a/gcc/rust/util/rust-lang-item.cc b/gcc/rust/util/rust-lang-item.cc index 731fd23f3148..c58ab401fd1c 100644 --- a/gcc/rust/util/rust-lang-item.cc +++ b/gcc/rust/util/rust-lang-item.cc @@ -124,9 +124,21 @@ const BiMap<std::string, LangItem::Kind> Rust::LangItem::lang_items = {{ {"discriminant_kind", Kind::DISCRIMINANT_KIND}, {"discriminant_type", Kind::DISCRIMINANT_TYPE}, {"manually_drop", Kind::MANUALLY_DROP}, + {"drop_in_place", Kind::DROP_IN_PLACE}, {"exchange_malloc", Kind::EXCHANGE_MALLOC}, {"owned_box", Kind::OWNED_BOX}, + {"oom", Kind::OOM}, + {"alloc_layout", Kind::ALLOC_LAYOUT}, + {"box_free", Kind::BOX_FREE}, + {"maybe_uninit", Kind::MAYBE_UNINIT}, + + {"future_trait", Kind::FUTURE_TRAIT}, + {"poll", Kind::POLL}, + {"Ready", Kind::READY}, + {"Pending", Kind::PENDING}, + {"generator", Kind::GENERATOR}, + {"generator_state", Kind::GENERATOR_STATE}, }}; tl::optional<LangItem::Kind> diff --git a/gcc/rust/util/rust-lang-item.h b/gcc/rust/util/rust-lang-item.h index 9684148f7554..d6bea1a8e432 100644 --- a/gcc/rust/util/rust-lang-item.h +++ b/gcc/rust/util/rust-lang-item.h @@ -160,9 +160,21 @@ public: DISCRIMINANT_KIND, MANUALLY_DROP, + DROP_IN_PLACE, EXCHANGE_MALLOC, OWNED_BOX, + OOM, + ALLOC_LAYOUT, + BOX_FREE, + MAYBE_UNINIT, + + FUTURE_TRAIT, + POLL, + READY, + PENDING, + GENERATOR, + GENERATOR_STATE, }; static const BiMap<std::string, Kind> lang_items; diff --git a/gcc/testsuite/rust/compile/lang-items-stub.rs b/gcc/testsuite/rust/compile/lang-items-stub.rs new file mode 100644 index 000000000000..09dd06e0ebe5 --- /dev/null +++ b/gcc/testsuite/rust/compile/lang-items-stub.rs @@ -0,0 +1,36 @@ +#![feature(no_core, lang_items)] +#![no_core] + + +#[lang = "sized"] +pub trait Sized {} + +#[lang = "future_trait"] // { dg-warning "...lang = .future_trait... is not implemented and has no effect" } +pub trait Future { + #[lang = "poll"] // { dg-warning "...lang = .poll... is not implemented and has no effect" } + fn poll() {} +} + +#[lang = "generator"] // { dg-warning "...lang = .generator... is not implemented and has no effect" } +pub trait Generator {} + +#[lang = "generator_state"] // { dg-warning "...lang = .generator_state... is not implemented and has no effect" } +pub enum GeneratorState {} + +#[lang = "box_free"] // { dg-warning "...lang = .box_free... is not implemented and has no effect" } +pub fn _box_free() {} + +#[repr(transparent)] +pub struct ManuallyDrop<T: ?Sized> { + _value: T, +} + +#[lang = "maybe_uninit"] // { dg-warning "...lang = .maybe_uninit... is not implemented and has no effect" } +#[repr(transparent)] +pub union MaybeUninit<T> { + uninit: (), + value: ManuallyDrop<T>, +} + +#[lang = "drop_in_place"] // { dg-warning "...lang = .drop_in_place... is not implemented and has no effect" } +pub unsafe fn drop_in_place<T: ?Sized>(to_drop: *mut T) {} diff --git a/gcc/testsuite/rust/compile/lang-items-symbol.rs b/gcc/testsuite/rust/compile/lang-items-symbol.rs new file mode 100644 index 000000000000..bc113d52b57f --- /dev/null +++ b/gcc/testsuite/rust/compile/lang-items-symbol.rs @@ -0,0 +1,8 @@ +#![feature(no_core, lang_items)] +#![no_core] + +#[lang = "alloc_layout"] +pub struct Layout; + +#[lang = "oom"] +pub fn _oom() {}
