Async drop codegen with async drop glue through templated coroutine

compiler/rustc_borrowck/src/lib.rs

@@ -696,7 +696,14 @@ impl<'mir, 'tcx, R> rustc_mir_dataflow::ResultsVisitor<'mir, 'tcx, R>
             TerminatorKind::SwitchInt { discr, targets: _ } => {
                 self.consume_operand(loc, (discr, span), flow_state);
             }
-            TerminatorKind::Drop { place, target: _, unwind: _, replace } => {
+            TerminatorKind::Drop {
+                place,
+                target: _,
+                unwind: _,
+                replace,
+                drop: _,
+                async_fut: _,
+            } => {
                 debug!(
                     "visit_terminator_drop \
                      loc: {:?} term: {:?} place: {:?} span: {:?}",

compiler/rustc_borrowck/src/polonius/loan_invalidations.rs

@@ -100,7 +100,14 @@ impl<'cx, 'tcx> Visitor<'tcx> for LoanInvalidationsGenerator<'cx, 'tcx> {
             TerminatorKind::SwitchInt { discr, targets: _ } => {
                 self.consume_operand(location, discr);
             }
-            TerminatorKind::Drop { place: drop_place, target: _, unwind: _, replace } => {
+            TerminatorKind::Drop {
+                place: drop_place,
+                target: _,
+                unwind: _,
+                replace,
+                drop: _,
+                async_fut: _,
+            } => {
                 let write_kind =
                     if *replace { WriteKind::Replace } else { WriteKind::StorageDeadOrDrop };
                 self.access_place(

compiler/rustc_borrowck/src/type_check/mod.rs

@@ -1690,8 +1690,14 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                 }
             }
             TerminatorKind::Unreachable => {}
-            TerminatorKind::Drop { target, unwind, .. }
-            | TerminatorKind::Assert { target, unwind, .. } => {
+            TerminatorKind::Drop { target, unwind, drop, .. } => {
+                self.assert_iscleanup(body, block_data, target, is_cleanup);
+                self.assert_iscleanup_unwind(body, block_data, unwind, is_cleanup);
+                if let Some(drop) = drop {
+                    self.assert_iscleanup(body, block_data, drop, is_cleanup);
+                }
+            }
+            TerminatorKind::Assert { target, unwind, .. } => {
                 self.assert_iscleanup(body, block_data, target, is_cleanup);
                 self.assert_iscleanup_unwind(body, block_data, unwind, is_cleanup);
             }

compiler/rustc_codegen_cranelift/src/abi/mod.rs

@@ -412,7 +412,9 @@ pub(crate) fn codegen_terminator_call<'tcx>(
                     Err(instance) => Some(instance),
                 }
             }
-            InstanceKind::DropGlue(_, None) | ty::InstanceKind::AsyncDropGlueCtorShim(_, None) => {
+            // We don't need AsyncDropGlueCtorShim here because it is not `noop func`,
+            // it is `func returning noop future`
+            InstanceKind::DropGlue(_, None) => {
                 // empty drop glue - a nop.
                 let dest = target.expect("Non terminating drop_in_place_real???");
                 let ret_block = fx.get_block(dest);
@@ -598,9 +600,8 @@ pub(crate) fn codegen_drop<'tcx>(
     let ty = drop_place.layout().ty;
     let drop_instance = Instance::resolve_drop_in_place(fx.tcx, ty).polymorphize(fx.tcx);
 
-    if let ty::InstanceKind::DropGlue(_, None) | ty::InstanceKind::AsyncDropGlueCtorShim(_, None) =
-        drop_instance.def
-    {
+    // AsyncDropGlueCtorShim can't be here
+    if let ty::InstanceKind::DropGlue(_, None) = drop_instance.def {
         // we don't actually need to drop anything
     } else {
         match ty.kind() {

compiler/rustc_codegen_cranelift/src/base.rs

@@ -546,7 +546,11 @@ fn codegen_fn_body(fx: &mut FunctionCx<'_, '_, '_>, start_block: Block) {
             | TerminatorKind::CoroutineDrop => {
                 bug!("shouldn't exist at codegen {:?}", bb_data.terminator());
             }
-            TerminatorKind::Drop { place, target, unwind: _, replace: _ } => {
+            TerminatorKind::Drop { place, target, unwind: _, replace: _, drop, async_fut } => {
+                assert!(
+                    async_fut.is_none() && drop.is_none(),
+                    "Async Drop must be expanded or reset to sync before codegen"
+                );
                 let drop_place = codegen_place(fx, *place);
                 crate::abi::codegen_drop(fx, source_info, drop_place, *target);
             }

compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/cpp_like.rs

@@ -683,8 +683,7 @@ fn build_union_fields_for_direct_tag_coroutine<'ll, 'tcx>(
         _ => unreachable!(),
     };
 
-    let coroutine_layout =
-        cx.tcx.coroutine_layout(coroutine_def_id, coroutine_args.kind_ty()).unwrap();
+    let coroutine_layout = cx.tcx.coroutine_layout(coroutine_def_id, coroutine_args.args).unwrap();
 
     let common_upvar_names = cx.tcx.closure_saved_names_of_captured_variables(coroutine_def_id);
     let variant_range = coroutine_args.variant_range(coroutine_def_id, cx.tcx);

compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/native.rs

@@ -158,10 +158,8 @@ pub(super) fn build_coroutine_di_node<'ll, 'tcx>(
             DIFlags::FlagZero,
         ),
         |cx, coroutine_type_di_node| {
-            let coroutine_layout = cx
-                .tcx
-                .coroutine_layout(coroutine_def_id, coroutine_args.as_coroutine().kind_ty())
-                .unwrap();
+            let coroutine_layout =
+                cx.tcx.coroutine_layout(coroutine_def_id, coroutine_args).unwrap();
 
             let Variants::Multiple { tag_encoding: TagEncoding::Direct, ref variants, .. } =
                 coroutine_type_and_layout.variants

compiler/rustc_codegen_ssa/src/back/symbol_export.rs

@@ -383,6 +383,16 @@ fn exported_symbols_provider_local(
                         },
                     ));
                 }
+                MonoItem::Fn(Instance { def: InstanceKind::AsyncDropGlue(_, ty), args: _ }) => {
+                    symbols.push((
+                        ExportedSymbol::AsyncDropGlue(ty),
+                        SymbolExportInfo {
+                            level: SymbolExportLevel::Rust,
+                            kind: SymbolExportKind::Text,
+                            used: false,
+                        },
+                    ));
+                }
                 _ => {
                     // Any other symbols don't qualify for sharing
                 }
@@ -406,6 +416,8 @@ fn upstream_monomorphizations_provider(
 
     let drop_in_place_fn_def_id = tcx.lang_items().drop_in_place_fn();
     let async_drop_in_place_fn_def_id = tcx.lang_items().async_drop_in_place_fn();
+    let async_drop_in_place_poll_fn_def_id = tcx.lang_items().async_drop_in_place_poll_fn();
+    let future_drop_poll_fn_def_id = tcx.lang_items().future_drop_poll_fn();
 
     for &cnum in cnums.iter() {
         for (exported_symbol, _) in tcx.exported_symbols(cnum).iter() {
@@ -424,8 +436,20 @@ fn upstream_monomorphizations_provider(
                     if let Some(async_drop_in_place_fn_def_id) = async_drop_in_place_fn_def_id {
                         (async_drop_in_place_fn_def_id, tcx.mk_args(&[ty.into()]))
                     } else {
-                        // `drop_in_place` in place does not exist, don't try
-                        // to use it.
+                        continue;
+                    }
+                }
+                ExportedSymbol::AsyncDropGlue(ty) => {
+                    if let Some(poll_fn_def_id) = async_drop_in_place_poll_fn_def_id {
+                        (poll_fn_def_id, tcx.mk_args(&[ty.into()]))
+                    } else {
+                        continue;
+                    }
+                }
+                ExportedSymbol::FutureDropPoll(ty) => {
+                    if let Some(poll_fn_def_id) = future_drop_poll_fn_def_id {
+                        (poll_fn_def_id, tcx.mk_args(&[ty.into()]))
+                    } else {
                         continue;
                     }
                 }
@@ -577,6 +601,20 @@ pub fn symbol_name_for_instance_in_crate<'tcx>(
                 instantiating_crate,
             )
         }
+        ExportedSymbol::AsyncDropGlue(ty) => {
+            rustc_symbol_mangling::symbol_name_for_instance_in_crate(
+                tcx,
+                Instance::resolve_async_drop_in_place_poll(tcx, ty),
+                instantiating_crate,
+            )
+        }
+        ExportedSymbol::FutureDropPoll(ty) => {
+            rustc_symbol_mangling::symbol_name_for_instance_in_crate(
+                tcx,
+                Instance::resolve_future_drop_poll(tcx, ty),
+                instantiating_crate,
+            )
+        }
         ExportedSymbol::NoDefId(symbol_name) => symbol_name.to_string(),
     }
 }
@@ -628,6 +666,8 @@ pub fn linking_symbol_name_for_instance_in_crate<'tcx>(
         // AsyncDropGlueCtorShim always use the Rust calling convention and thus follow the
         // target's default symbol decoration scheme.
         ExportedSymbol::AsyncDropGlueCtorShim(..) => None,
+        ExportedSymbol::AsyncDropGlue(..) => None,
+        ExportedSymbol::FutureDropPoll(..) => None,
         // NoDefId always follow the target's default symbol decoration scheme.
         ExportedSymbol::NoDefId(..) => None,
         // ThreadLocalShim always follow the target's default symbol decoration scheme.

compiler/rustc_codegen_ssa/src/mir/block.rs

@@ -854,10 +854,9 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
 
         let def = instance.map(|i| i.def);
 
-        if let Some(
-            ty::InstanceKind::DropGlue(_, None) | ty::InstanceKind::AsyncDropGlueCtorShim(_, None),
-        ) = def
-        {
+        // We don't need AsyncDropGlueCtorShim here because it is not `noop func`,
+        // it is `func returning noop future`
+        if let Some(ty::InstanceKind::DropGlue(_, None)) = def {
             // Empty drop glue; a no-op.
             let target = target.unwrap();
             return helper.funclet_br(self, bx, target, mergeable_succ);
@@ -1363,16 +1362,21 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 MergingSucc::False
             }
 
-            mir::TerminatorKind::Drop { place, target, unwind, replace: _ } => self
-                .codegen_drop_terminator(
+            mir::TerminatorKind::Drop { place, target, unwind, replace: _, drop, async_fut } => {
+                assert!(
+                    async_fut.is_none() && drop.is_none(),
+                    "Async Drop must be expanded or reset to sync before codegen"
+                );
+                self.codegen_drop_terminator(
                     helper,
                     bx,
                     &terminator.source_info,
                     place,
                     target,
                     unwind,
                     mergeable_succ(),
-                ),
+                )
+            }
 
             mir::TerminatorKind::Assert { ref cond, expected, ref msg, target, unwind } => self
                 .codegen_assert_terminator(

compiler/rustc_const_eval/src/const_eval/machine.rs

@@ -572,6 +572,7 @@ impl<'tcx> interpret::Machine<'tcx> for CompileTimeMachine<'tcx> {
             RemainderByZero(op) => RemainderByZero(eval_to_int(op)?),
             ResumedAfterReturn(coroutine_kind) => ResumedAfterReturn(*coroutine_kind),
             ResumedAfterPanic(coroutine_kind) => ResumedAfterPanic(*coroutine_kind),
+            ResumedAfterDrop(coroutine_kind) => ResumedAfterDrop(*coroutine_kind),
             MisalignedPointerDereference { ref required, ref found } => {
                 MisalignedPointerDereference {
                     required: eval_to_int(required)?,

compiler/rustc_const_eval/src/interpret/terminator.rs

@@ -172,7 +172,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
                 }
             }
 
-            Drop { place, target, unwind, replace: _ } => {
+            Drop { place, target, unwind, replace: _, drop: _, async_fut: _ } => {
                 let place = self.eval_place(place)?;
                 let instance = Instance::resolve_drop_in_place(*self.tcx, place.layout.ty);
                 if let ty::InstanceKind::DropGlue(_, None) = instance.def {
@@ -587,6 +587,8 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
             | ty::InstanceKind::FnPtrAddrShim(..)
             | ty::InstanceKind::ThreadLocalShim(..)
             | ty::InstanceKind::AsyncDropGlueCtorShim(..)
+            | ty::InstanceKind::AsyncDropGlue(..)
+            | ty::InstanceKind::FutureDropPollShim(..)
             | ty::InstanceKind::Item(_) => {
                 // We need MIR for this fn
                 let Some((body, instance)) = M::find_mir_or_eval_fn(

compiler/rustc_feature/src/unstable.rs

@@ -357,6 +357,8 @@ declare_features! (
     (unstable, associated_type_defaults, "1.2.0", Some(29661)),
     /// Allows `async || body` closures.
     (unstable, async_closure, "1.37.0", Some(62290)),
+    /// Allows implementing `AsyncDrop`.
+    (incomplete, async_drop, "CURRENT_RUSTC_VERSION", None),
     /// Allows `#[track_caller]` on async functions.
     (unstable, async_fn_track_caller, "1.73.0", Some(110011)),
     /// Allows `for await` loops.

compiler/rustc_hir/src/lang_items.rs

@@ -167,19 +167,10 @@ language_item_table! {
 
     Drop,                    sym::drop,                drop_trait,                 Target::Trait,          GenericRequirement::None;
     Destruct,                sym::destruct,            destruct_trait,             Target::Trait,          GenericRequirement::None;
-
-    AsyncDrop,               sym::async_drop,          async_drop_trait,           Target::Trait,          GenericRequirement::Exact(0);
-    AsyncDestruct,           sym::async_destruct,      async_destruct_trait,       Target::Trait,          GenericRequirement::Exact(0);
+    AsyncDrop,               sym::async_drop,          async_drop_trait,           Target::Trait,          GenericRequirement::None;
     AsyncDropInPlace,        sym::async_drop_in_place, async_drop_in_place_fn,     Target::Fn,             GenericRequirement::Exact(1);
-    SurfaceAsyncDropInPlace, sym::surface_async_drop_in_place, surface_async_drop_in_place_fn, Target::Fn, GenericRequirement::Exact(1);
-    AsyncDropSurfaceDropInPlace, sym::async_drop_surface_drop_in_place, async_drop_surface_drop_in_place_fn, Target::Fn, GenericRequirement::Exact(1);
-    AsyncDropSlice,          sym::async_drop_slice,    async_drop_slice_fn,        Target::Fn,             GenericRequirement::Exact(1);
-    AsyncDropChain,          sym::async_drop_chain,    async_drop_chain_fn,        Target::Fn,             GenericRequirement::Exact(2);
-    AsyncDropNoop,           sym::async_drop_noop,     async_drop_noop_fn,         Target::Fn,             GenericRequirement::Exact(0);
-    AsyncDropDeferredDropInPlace, sym::async_drop_deferred_drop_in_place, async_drop_deferred_drop_in_place_fn, Target::Fn, GenericRequirement::Exact(1);
-    AsyncDropFuse,           sym::async_drop_fuse,     async_drop_fuse_fn,         Target::Fn,             GenericRequirement::Exact(1);
-    AsyncDropDefer,          sym::async_drop_defer,    async_drop_defer_fn,        Target::Fn,             GenericRequirement::Exact(1);
-    AsyncDropEither,         sym::async_drop_either,   async_drop_either_fn,       Target::Fn,             GenericRequirement::Exact(3);
+    AsyncDropInPlacePoll,    sym::async_drop_in_place_poll, async_drop_in_place_poll_fn, Target::Closure,  GenericRequirement::Exact(1);
+    FutureDropPoll,          sym::future_drop_poll,    future_drop_poll_fn,        Target::Fn,             GenericRequirement::Exact(1);
 
     CoerceUnsized,           sym::coerce_unsized,      coerce_unsized_trait,       Target::Trait,          GenericRequirement::Minimum(1);
     DispatchFromDyn,         sym::dispatch_from_dyn,   dispatch_from_dyn_trait,    Target::Trait,          GenericRequirement::Minimum(1);
@@ -294,6 +285,10 @@ language_item_table! {
     PanicAsyncFnResumedPanic, sym::panic_const_async_fn_resumed_panic, panic_const_async_fn_resumed_panic, Target::Fn, GenericRequirement::None;
     PanicAsyncGenFnResumedPanic, sym::panic_const_async_gen_fn_resumed_panic, panic_const_async_gen_fn_resumed_panic, Target::Fn, GenericRequirement::None;
     PanicGenFnNonePanic, sym::panic_const_gen_fn_none_panic, panic_const_gen_fn_none_panic, Target::Fn, GenericRequirement::None;
+    PanicCoroutineResumedDrop, sym::panic_const_coroutine_resumed_drop, panic_const_coroutine_resumed_drop, Target::Fn, GenericRequirement::None;
+    PanicAsyncFnResumedDrop, sym::panic_const_async_fn_resumed_drop, panic_const_async_fn_resumed_drop, Target::Fn, GenericRequirement::None;
+    PanicAsyncGenFnResumedDrop, sym::panic_const_async_gen_fn_resumed_drop, panic_const_async_gen_fn_resumed_drop, Target::Fn, GenericRequirement::None;
+    PanicGenFnNoneDrop, sym::panic_const_gen_fn_none_drop, panic_const_gen_fn_none_drop, Target::Fn, GenericRequirement::None;
     /// libstd panic entry point. Necessary for const eval to be able to catch it
     BeginPanic,              sym::begin_panic,         begin_panic_fn,             Target::Fn,             GenericRequirement::None;
 
@@ -307,7 +302,7 @@ language_item_table! {
 
     ExchangeMalloc,          sym::exchange_malloc,     exchange_malloc_fn,         Target::Fn,             GenericRequirement::None;
     DropInPlace,             sym::drop_in_place,       drop_in_place_fn,           Target::Fn,             GenericRequirement::Minimum(1);
-    FallbackSurfaceDrop,     sym::fallback_surface_drop, fallback_surface_drop_fn, Target::Fn,             GenericRequirement::None;
+    DropInPlaceFuture,       sym::drop_in_place_future,drop_in_place_future_fn,    Target::Fn,             GenericRequirement::Exact(1);
     AllocLayout,             sym::alloc_layout,        alloc_layout,               Target::Struct,         GenericRequirement::None;
 
     Start,                   sym::start,               start_fn,                   Target::Fn,             GenericRequirement::Exact(1);
@@ -361,6 +356,7 @@ language_item_table! {
     ResumeTy,                sym::ResumeTy,            resume_ty,                  Target::Struct,         GenericRequirement::None;
     GetContext,              sym::get_context,         get_context_fn,             Target::Fn,             GenericRequirement::None;
 
+    Noop,                    sym::Noop,                noop,                       Target::Struct,         GenericRequirement::None;
     Context,                 sym::Context,             context,                    Target::Struct,         GenericRequirement::None;
     FuturePoll,              sym::poll,                future_poll_fn,             Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None;
 

compiler/rustc_hir_typeck/src/callee.rs

@@ -39,11 +39,9 @@ pub fn check_legal_trait_for_method_call(
     receiver: Option<Span>,
     expr_span: Span,
     trait_id: DefId,
-    body_id: DefId,
+    _body_id: DefId,
 ) -> Result<(), ErrorGuaranteed> {
-    if tcx.is_lang_item(trait_id, LangItem::Drop)
-        && tcx.lang_items().fallback_surface_drop_fn() != Some(body_id)
-    {
+    if tcx.is_lang_item(trait_id, LangItem::Drop) {
         let sugg = if let Some(receiver) = receiver.filter(|s| !s.is_empty()) {
             errors::ExplicitDestructorCallSugg::Snippet {
                 lo: expr_span.shrink_to_lo(),

compiler/rustc_middle/messages.ftl

@@ -1,17 +1,23 @@
 middle_adjust_for_foreign_abi_error =
     target architecture {$arch} does not support `extern {$abi}` ABI
 
+middle_assert_async_resume_after_drop = `async fn` resumed after async drop
+
 middle_assert_async_resume_after_panic = `async fn` resumed after panicking
 
 middle_assert_async_resume_after_return = `async fn` resumed after completion
 
+middle_assert_coroutine_resume_after_drop = coroutine resumed after async drop
+
 middle_assert_coroutine_resume_after_panic = coroutine resumed after panicking
 
 middle_assert_coroutine_resume_after_return = coroutine resumed after completion
 
 middle_assert_divide_by_zero =
     attempt to divide `{$val}` by zero
 
+middle_assert_gen_resume_after_drop = `gen` fn or block cannot be further iterated on after it async dropped
+
 middle_assert_gen_resume_after_panic = `gen` fn or block cannot be further iterated on after it panicked
 
 middle_assert_misaligned_ptr_deref =