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Rollup merge of #149950 - WaffleLapkin:inlines-ur-mu-into-asm, r=jdonszelmann

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Simplify how inline asm handles `MaybeUninit`

This is just better, but this is also allows it to handle changes from https://github.com/rust-lang/rust/pull/149614 (i.e. `ManuallyDrop` containing `MaybeDangle`).
This commit is contained in:
Stuart Cook 2025-12-16 14:40:44 +11:00 • committed by GitHub
commit 461d0d0dfd
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2 changed files with 3 additions and 25 deletions
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14
compiler/rustc_codegen_cranelift/src/inline_asm.rs
View file

@ -857,19 +857,9 @@ fn call_inline_asm<'tcx>(
fn asm_clif_type<'tcx>(fx: &FunctionCx<'_, '_, 'tcx>, ty: Ty<'tcx>) -> Option<types::Type> {
match ty.kind() {
// Adapted from https://github.com/rust-lang/rust/blob/f3c66088610c1b80110297c2d9a8b5f9265b013f/compiler/rustc_hir_analysis/src/check/intrinsicck.rs#L136-L151
// Adapted from https://github.com/rust-lang/rust/blob/df44a57fd29fca899ce473f85ed64efd0708dd7c/compiler/rustc_hir_typeck/src/inline_asm.rs#L180-L183
ty::Adt(adt, args) if fx.tcx.is_lang_item(adt.did(), LangItem::MaybeUninit) => {
let fields = &adt.non_enum_variant().fields;
let ty = fields[FieldIdx::ONE].ty(fx.tcx, args);
let ty::Adt(ty, args) = ty.kind() else {
unreachable!("expected first field of `MaybeUninit` to be an ADT")
};
assert!(
ty.is_manually_drop(),
"expected first field of `MaybeUninit` to be `ManuallyDrop`"
);
let fields = &ty.non_enum_variant().fields;
let ty = fields[FieldIdx::ZERO].ty(fx.tcx, args);
let ty = args.type_at(0);
fx.clif_type(ty)
}
_ => fx.clif_type(ty),

14
compiler/rustc_hir_typeck/src/inline_asm.rs
View file

@ -178,19 +178,7 @@ impl<'a, 'tcx> InlineAsmCtxt<'a, 'tcx> {
ty::Never if is_input => return None,
_ if ty.references_error() => return None,
ty::Adt(adt, args) if self.tcx().is_lang_item(adt.did(), LangItem::MaybeUninit) => {
let fields = &adt.non_enum_variant().fields;
let ty = fields[FieldIdx::ONE].ty(self.tcx(), args);
// FIXME: Are we just trying to map to the `T` in `MaybeUninit<T>`?
// If so, just get it from the args.
let ty::Adt(ty, args) = ty.kind() else {
unreachable!("expected first field of `MaybeUninit` to be an ADT")
};
assert!(
ty.is_manually_drop(),
"expected first field of `MaybeUninit` to be `ManuallyDrop`"
);
let fields = &ty.non_enum_variant().fields;
let ty = fields[FieldIdx::ZERO].ty(self.tcx(), args);
let ty = args.type_at(0);
self.get_asm_ty(expr.span, ty)
}
_ => self.get_asm_ty(expr.span, ty),