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Transform async ResumeTy in generator transform
- Eliminates all the `get_context` calls that async lowering created. - Replace all `Local` `ResumeTy` types with `&mut Context<'_>`. The `Local`s that have their types replaced are: - The `resume` argument itself. - The argument to `get_context`. - The yielded value of a `yield`. The `ResumeTy` hides a `&mut Context<'_>` behind an unsafe raw pointer, and the `get_context` function is being used to convert that back to a `&mut Context<'_>`. Ideally the async lowering would not use the `ResumeTy`/`get_context` indirection, but rather directly use `&mut Context<'_>`, however that would currently lead to higher-kinded lifetime errors. See <https://github.com/rust-lang/rust/issues/105501>. The async lowering step and the type / lifetime inference / checking are still using the `ResumeTy` indirection for the time being, and that indirection is removed here. After this transform, the generator body only knows about `&mut Context<'_>`.
This commit is contained in:
Arpad Borsos
parent
6ba6d22bdf
commit
96931a787a
@ -291,6 +291,7 @@ language_item_table! {
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IdentityFuture, sym::identity_future, identity_future_fn, Target::Fn, GenericRequirement::None;
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GetContext, sym::get_context, get_context_fn, Target::Fn, GenericRequirement::None;
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Context, sym::Context, context, Target::Struct, GenericRequirement::None;
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FuturePoll, sym::poll, future_poll_fn, Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None;
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FromFrom, sym::from, from_fn, Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None;
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@ -1952,6 +1952,15 @@ impl<'tcx> TyCtxt<'tcx> {
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self.mk_ty(GeneratorWitness(types))
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}
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/// Creates a `&mut Context<'_>` [`Ty`] with erased lifetimes.
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pub fn mk_task_context(self) -> Ty<'tcx> {
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let context_did = self.require_lang_item(LangItem::Context, None);
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let context_adt_ref = self.adt_def(context_did);
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let context_substs = self.intern_substs(&[self.lifetimes.re_erased.into()]);
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let context_ty = self.mk_adt(context_adt_ref, context_substs);
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self.mk_mut_ref(self.lifetimes.re_erased, context_ty)
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}
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#[inline]
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pub fn mk_ty_var(self, v: TyVid) -> Ty<'tcx> {
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self.mk_ty_infer(TyVar(v))
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@ -460,6 +460,104 @@ fn replace_local<'tcx>(
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new_local
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}
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/// Transforms the `body` of the generator applying the following transforms:
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///
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/// - Eliminates all the `get_context` calls that async lowering created.
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/// - Replace all `Local` `ResumeTy` types with `&mut Context<'_>` (`context_mut_ref`).
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///
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/// The `Local`s that have their types replaced are:
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/// - The `resume` argument itself.
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/// - The argument to `get_context`.
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/// - The yielded value of a `yield`.
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///
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/// The `ResumeTy` hides a `&mut Context<'_>` behind an unsafe raw pointer, and the
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/// `get_context` function is being used to convert that back to a `&mut Context<'_>`.
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///
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/// Ideally the async lowering would not use the `ResumeTy`/`get_context` indirection,
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/// but rather directly use `&mut Context<'_>`, however that would currently
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/// lead to higher-kinded lifetime errors.
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/// See <https://github.com/rust-lang/rust/issues/105501>.
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///
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/// The async lowering step and the type / lifetime inference / checking are
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/// still using the `ResumeTy` indirection for the time being, and that indirection
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/// is removed here. After this transform, the generator body only knows about `&mut Context<'_>`.
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fn transform_async_context<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
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let context_mut_ref = tcx.mk_task_context();
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// replace the type of the `resume` argument
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replace_resume_ty_local(tcx, body, Local::new(2), context_mut_ref);
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let get_context_def_id = tcx.require_lang_item(LangItem::GetContext, None);
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for bb in BasicBlock::new(0)..body.basic_blocks.next_index() {
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let bb_data = &body[bb];
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if bb_data.is_cleanup {
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continue;
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}
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match &bb_data.terminator().kind {
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TerminatorKind::Call { func, .. } => {
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let func_ty = func.ty(body, tcx);
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if let ty::FnDef(def_id, _) = *func_ty.kind() {
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if def_id == get_context_def_id {
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let local = eliminate_get_context_call(&mut body[bb]);
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replace_resume_ty_local(tcx, body, local, context_mut_ref);
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}
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} else {
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continue;
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}
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}
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TerminatorKind::Yield { resume_arg, .. } => {
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replace_resume_ty_local(tcx, body, resume_arg.local, context_mut_ref);
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}
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_ => {}
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}
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}
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}
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fn eliminate_get_context_call<'tcx>(bb_data: &mut BasicBlockData<'tcx>) -> Local {
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let terminator = bb_data.terminator.take().unwrap();
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if let TerminatorKind::Call { mut args, destination, target, .. } = terminator.kind {
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let arg = args.pop().unwrap();
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let local = arg.place().unwrap().local;
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let arg = Rvalue::Use(arg);
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let assign = Statement {
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source_info: terminator.source_info,
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kind: StatementKind::Assign(Box::new((destination, arg))),
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};
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bb_data.statements.push(assign);
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bb_data.terminator = Some(Terminator {
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source_info: terminator.source_info,
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kind: TerminatorKind::Goto { target: target.unwrap() },
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});
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local
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} else {
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bug!();
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}
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}
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#[cfg_attr(not(debug_assertions), allow(unused))]
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fn replace_resume_ty_local<'tcx>(
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tcx: TyCtxt<'tcx>,
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body: &mut Body<'tcx>,
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local: Local,
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context_mut_ref: Ty<'tcx>,
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) {
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let local_ty = std::mem::replace(&mut body.local_decls[local].ty, context_mut_ref);
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// We have to replace the `ResumeTy` that is used for type and borrow checking
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// with `&mut Context<'_>` in MIR.
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#[cfg(debug_assertions)]
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{
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if let ty::Adt(resume_ty_adt, _) = local_ty.kind() {
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let expected_adt = tcx.adt_def(tcx.require_lang_item(LangItem::ResumeTy, None));
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assert_eq!(*resume_ty_adt, expected_adt);
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} else {
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panic!("expected `ResumeTy`, found `{:?}`", local_ty);
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};
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}
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}
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struct LivenessInfo {
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/// Which locals are live across any suspension point.
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saved_locals: GeneratorSavedLocals,
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@ -1283,13 +1381,13 @@ impl<'tcx> MirPass<'tcx> for StateTransform {
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}
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};
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let is_async_kind = body.generator_kind().unwrap() != GeneratorKind::Gen;
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let is_async_kind = matches!(body.generator_kind(), Some(GeneratorKind::Async(_)));
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let (state_adt_ref, state_substs) = if is_async_kind {
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// Compute Poll<return_ty>
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let state_did = tcx.require_lang_item(LangItem::Poll, None);
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let state_adt_ref = tcx.adt_def(state_did);
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let state_substs = tcx.intern_substs(&[body.return_ty().into()]);
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(state_adt_ref, state_substs)
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let poll_did = tcx.require_lang_item(LangItem::Poll, None);
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let poll_adt_ref = tcx.adt_def(poll_did);
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let poll_substs = tcx.intern_substs(&[body.return_ty().into()]);
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(poll_adt_ref, poll_substs)
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} else {
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// Compute GeneratorState<yield_ty, return_ty>
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let state_did = tcx.require_lang_item(LangItem::GeneratorState, None);
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@ -1303,13 +1401,19 @@ impl<'tcx> MirPass<'tcx> for StateTransform {
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// RETURN_PLACE then is a fresh unused local with type ret_ty.
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let new_ret_local = replace_local(RETURN_PLACE, ret_ty, body, tcx);
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// Replace all occurrences of `ResumeTy` with `&mut Context<'_>` within async bodies.
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if is_async_kind {
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transform_async_context(tcx, body);
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}
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// We also replace the resume argument and insert an `Assign`.
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// This is needed because the resume argument `_2` might be live across a `yield`, in which
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// case there is no `Assign` to it that the transform can turn into a store to the generator
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// state. After the yield the slot in the generator state would then be uninitialized.
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let resume_local = Local::new(2);
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let new_resume_local =
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replace_local(resume_local, body.local_decls[resume_local].ty, body, tcx);
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let resume_ty =
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if is_async_kind { tcx.mk_task_context() } else { body.local_decls[resume_local].ty };
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let new_resume_local = replace_local(resume_local, resume_ty, body, tcx);
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// When first entering the generator, move the resume argument into its new local.
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let source_info = SourceInfo::outermost(body.span);
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@ -164,6 +164,7 @@ symbols! {
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Capture,
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Center,
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Clone,
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Context,
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Continue,
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Copy,
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Count,
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@ -108,21 +108,41 @@ fn fn_sig_for_fn_abi<'tcx>(
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// `Generator::resume(...) -> GeneratorState` function in case we
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// have an ordinary generator, or the `Future::poll(...) -> Poll`
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// function in case this is a special generator backing an async construct.
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let ret_ty = if tcx.generator_is_async(did) {
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let state_did = tcx.require_lang_item(LangItem::Poll, None);
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let state_adt_ref = tcx.adt_def(state_did);
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let state_substs = tcx.intern_substs(&[sig.return_ty.into()]);
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tcx.mk_adt(state_adt_ref, state_substs)
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let (resume_ty, ret_ty) = if tcx.generator_is_async(did) {
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// The signature should be `Future::poll(_, &mut Context<'_>) -> Poll<Output>`
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let poll_did = tcx.require_lang_item(LangItem::Poll, None);
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let poll_adt_ref = tcx.adt_def(poll_did);
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let poll_substs = tcx.intern_substs(&[sig.return_ty.into()]);
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let ret_ty = tcx.mk_adt(poll_adt_ref, poll_substs);
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// We have to replace the `ResumeTy` that is used for type and borrow checking
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// with `&mut Context<'_>` which is used in codegen.
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#[cfg(debug_assertions)]
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{
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if let ty::Adt(resume_ty_adt, _) = sig.resume_ty.kind() {
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let expected_adt =
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tcx.adt_def(tcx.require_lang_item(LangItem::ResumeTy, None));
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assert_eq!(*resume_ty_adt, expected_adt);
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} else {
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panic!("expected `ResumeTy`, found `{:?}`", sig.resume_ty);
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};
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}
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let context_mut_ref = tcx.mk_task_context();
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(context_mut_ref, ret_ty)
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} else {
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// The signature should be `Generator::resume(_, Resume) -> GeneratorState<Yield, Return>`
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let state_did = tcx.require_lang_item(LangItem::GeneratorState, None);
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let state_adt_ref = tcx.adt_def(state_did);
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let state_substs = tcx.intern_substs(&[sig.yield_ty.into(), sig.return_ty.into()]);
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tcx.mk_adt(state_adt_ref, state_substs)
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let ret_ty = tcx.mk_adt(state_adt_ref, state_substs);
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(sig.resume_ty, ret_ty)
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};
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ty::Binder::bind_with_vars(
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tcx.mk_fn_sig(
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[env_ty, sig.resume_ty].iter(),
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[env_ty, resume_ty].iter(),
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&ret_ty,
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false,
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hir::Unsafety::Normal,
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@ -112,6 +112,10 @@ pub unsafe fn get_context<'a, 'b>(cx: ResumeTy) -> &'a mut Context<'b> {
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unsafe { &mut *cx.0.as_ptr().cast() }
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}
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// FIXME(swatinem): This fn is currently needed to work around shortcomings
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// in type and lifetime inference.
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// See the comment at the bottom of `LoweringContext::make_async_expr` and
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// <https://github.com/rust-lang/rust/issues/104826>.
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#[doc(hidden)]
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#[unstable(feature = "gen_future", issue = "50547")]
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#[inline]
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@ -174,6 +174,7 @@ impl RawWakerVTable {
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/// Currently, `Context` only serves to provide access to a [`&Waker`](Waker)
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/// which can be used to wake the current task.
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#[stable(feature = "futures_api", since = "1.36.0")]
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#[cfg_attr(not(bootstrap), lang = "Context")]
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pub struct Context<'a> {
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waker: &'a Waker,
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// Ensure we future-proof against variance changes by forcing
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@ -0,0 +1,41 @@
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// MIR for `a::{closure#0}` 0 generator_resume
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/* generator_layout = GeneratorLayout {
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field_tys: {},
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variant_fields: {
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Unresumed(0): [],
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Returned (1): [],
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Panicked (2): [],
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},
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storage_conflicts: BitMatrix(0x0) {},
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} */
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fn a::{closure#0}(_1: Pin<&mut [async fn body@$DIR/async_await.rs:11:14: 11:16]>, _2: &mut Context<'_>) -> Poll<()> {
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debug _task_context => _4; // in scope 0 at $DIR/async_await.rs:+0:14: +0:16
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let mut _0: std::task::Poll<()>; // return place in scope 0 at $DIR/async_await.rs:+0:14: +0:16
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let mut _3: (); // in scope 0 at $DIR/async_await.rs:+0:14: +0:16
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let mut _4: &mut std::task::Context<'_>; // in scope 0 at $DIR/async_await.rs:+0:14: +0:16
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let mut _5: u32; // in scope 0 at $DIR/async_await.rs:+0:14: +0:16
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bb0: {
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_5 = discriminant((*(_1.0: &mut [async fn body@$DIR/async_await.rs:11:14: 11:16]))); // scope 0 at $DIR/async_await.rs:+0:14: +0:16
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switchInt(move _5) -> [0: bb1, 1: bb2, otherwise: bb3]; // scope 0 at $DIR/async_await.rs:+0:14: +0:16
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}
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bb1: {
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_4 = move _2; // scope 0 at $DIR/async_await.rs:+0:14: +0:16
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_3 = const (); // scope 0 at $DIR/async_await.rs:+0:14: +0:16
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Deinit(_0); // scope 0 at $DIR/async_await.rs:+0:16: +0:16
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((_0 as Ready).0: ()) = move _3; // scope 0 at $DIR/async_await.rs:+0:16: +0:16
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discriminant(_0) = 0; // scope 0 at $DIR/async_await.rs:+0:16: +0:16
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discriminant((*(_1.0: &mut [async fn body@$DIR/async_await.rs:11:14: 11:16]))) = 1; // scope 0 at $DIR/async_await.rs:+0:16: +0:16
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return; // scope 0 at $DIR/async_await.rs:+0:16: +0:16
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}
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bb2: {
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assert(const false, "`async fn` resumed after completion") -> bb2; // scope 0 at $DIR/async_await.rs:+0:14: +0:16
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}
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bb3: {
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unreachable; // scope 0 at $DIR/async_await.rs:+0:14: +0:16
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}
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}
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@ -0,0 +1,337 @@
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// MIR for `b::{closure#0}` 0 generator_resume
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/* generator_layout = GeneratorLayout {
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field_tys: {
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_0: impl std::future::Future<Output = ()>,
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_1: impl std::future::Future<Output = ()>,
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},
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variant_fields: {
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Unresumed(0): [],
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Returned (1): [],
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Panicked (2): [],
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Suspend0 (3): [_0],
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Suspend1 (4): [_1],
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},
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storage_conflicts: BitMatrix(2x2) {
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(_0, _0),
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(_1, _1),
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},
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} */
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fn b::{closure#0}(_1: Pin<&mut [async fn body@$DIR/async_await.rs:14:18: 17:2]>, _2: &mut Context<'_>) -> Poll<()> {
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debug _task_context => _38; // in scope 0 at $DIR/async_await.rs:+0:18: +3:2
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let mut _0: std::task::Poll<()>; // return place in scope 0 at $DIR/async_await.rs:+0:18: +3:2
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let _3: (); // in scope 0 at $DIR/async_await.rs:+1:5: +1:14
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let mut _4: impl std::future::Future<Output = ()>; // in scope 0 at $DIR/async_await.rs:+1:8: +1:14
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let mut _5: impl std::future::Future<Output = ()>; // in scope 0 at $DIR/async_await.rs:+1:5: +1:8
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let mut _6: impl std::future::Future<Output = ()>; // in scope 0 at $DIR/async_await.rs:+1:8: +1:14
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let mut _7: (); // in scope 0 at $DIR/async_await.rs:+0:18: +3:2
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let _8: (); // in scope 0 at $DIR/async_await.rs:+1:8: +1:14
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let mut _9: std::task::Poll<()>; // in scope 0 at $DIR/async_await.rs:+1:8: +1:14
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let mut _10: std::pin::Pin<&mut impl std::future::Future<Output = ()>>; // in scope 0 at $DIR/async_await.rs:+1:8: +1:14
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let mut _11: &mut impl std::future::Future<Output = ()>; // in scope 0 at $DIR/async_await.rs:+1:8: +1:14
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let mut _12: &mut impl std::future::Future<Output = ()>; // in scope 0 at $DIR/async_await.rs:+1:8: +1:14
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let mut _13: &mut std::task::Context<'_>; // in scope 0 at $DIR/async_await.rs:+1:5: +1:14
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let mut _14: &mut std::task::Context<'_>; // in scope 0 at $DIR/async_await.rs:+1:5: +1:14
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let mut _15: &mut std::task::Context<'_>; // in scope 0 at $DIR/async_await.rs:+1:8: +1:14
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let mut _16: isize; // in scope 0 at $DIR/async_await.rs:+1:8: +1:14
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let mut _18: !; // in scope 0 at $DIR/async_await.rs:+1:5: +1:14
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let mut _19: &mut std::task::Context<'_>; // in scope 0 at $DIR/async_await.rs:+1:8: +1:14
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let mut _20: (); // in scope 0 at $DIR/async_await.rs:+1:8: +1:14
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let mut _21: impl std::future::Future<Output = ()>; // in scope 0 at $DIR/async_await.rs:+2:8: +2:14
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let mut _22: impl std::future::Future<Output = ()>; // in scope 0 at $DIR/async_await.rs:+2:5: +2:8
|
||||
let mut _23: impl std::future::Future<Output = ()>; // in scope 0 at $DIR/async_await.rs:+2:8: +2:14
|
||||
let _24: (); // in scope 0 at $DIR/async_await.rs:+2:8: +2:14
|
||||
let mut _25: std::task::Poll<()>; // in scope 0 at $DIR/async_await.rs:+2:8: +2:14
|
||||
let mut _26: std::pin::Pin<&mut impl std::future::Future<Output = ()>>; // in scope 0 at $DIR/async_await.rs:+2:8: +2:14
|
||||
let mut _27: &mut impl std::future::Future<Output = ()>; // in scope 0 at $DIR/async_await.rs:+2:8: +2:14
|
||||
let mut _28: &mut impl std::future::Future<Output = ()>; // in scope 0 at $DIR/async_await.rs:+2:8: +2:14
|
||||
let mut _29: &mut std::task::Context<'_>; // in scope 0 at $DIR/async_await.rs:+2:5: +2:14
|
||||
let mut _30: &mut std::task::Context<'_>; // in scope 0 at $DIR/async_await.rs:+2:5: +2:14
|
||||
let mut _31: &mut std::task::Context<'_>; // in scope 0 at $DIR/async_await.rs:+2:8: +2:14
|
||||
let mut _32: isize; // in scope 0 at $DIR/async_await.rs:+2:8: +2:14
|
||||
let mut _34: !; // in scope 0 at $DIR/async_await.rs:+2:5: +2:14
|
||||
let mut _35: &mut std::task::Context<'_>; // in scope 0 at $DIR/async_await.rs:+2:8: +2:14
|
||||
let mut _36: (); // in scope 0 at $DIR/async_await.rs:+2:8: +2:14
|
||||
let mut _37: (); // in scope 0 at $DIR/async_await.rs:+0:18: +3:2
|
||||
let mut _38: &mut std::task::Context<'_>; // in scope 0 at $DIR/async_await.rs:+0:18: +3:2
|
||||
let mut _39: u32; // in scope 0 at $DIR/async_await.rs:+0:18: +3:2
|
||||
scope 1 {
|
||||
debug __awaitee => (((*(_1.0: &mut [async fn body@$DIR/async_await.rs:14:18: 17:2])) as variant#3).0: impl std::future::Future<Output = ()>); // in scope 1 at $DIR/async_await.rs:+1:8: +1:14
|
||||
let _17: (); // in scope 1 at $DIR/async_await.rs:+1:5: +1:14
|
||||
scope 2 {
|
||||
}
|
||||
scope 3 {
|
||||
debug result => _17; // in scope 3 at $DIR/async_await.rs:+1:5: +1:14
|
||||
}
|
||||
}
|
||||
scope 4 {
|
||||
debug __awaitee => (((*(_1.0: &mut [async fn body@$DIR/async_await.rs:14:18: 17:2])) as variant#4).0: impl std::future::Future<Output = ()>); // in scope 4 at $DIR/async_await.rs:+2:8: +2:14
|
||||
let _33: (); // in scope 4 at $DIR/async_await.rs:+2:5: +2:14
|
||||
scope 5 {
|
||||
}
|
||||
scope 6 {
|
||||
debug result => _33; // in scope 6 at $DIR/async_await.rs:+2:5: +2:14
|
||||
}
|
||||
}
|
||||
|
||||
bb0: {
|
||||
_39 = discriminant((*(_1.0: &mut [async fn body@$DIR/async_await.rs:14:18: 17:2]))); // scope 0 at $DIR/async_await.rs:+0:18: +3:2
|
||||
switchInt(move _39) -> [0: bb1, 1: bb29, 3: bb27, 4: bb28, otherwise: bb30]; // scope 0 at $DIR/async_await.rs:+0:18: +3:2
|
||||
}
|
||||
|
||||
bb1: {
|
||||
_38 = move _2; // scope 0 at $DIR/async_await.rs:+0:18: +3:2
|
||||
StorageLive(_3); // scope 0 at $DIR/async_await.rs:+1:5: +1:14
|
||||
StorageLive(_4); // scope 0 at $DIR/async_await.rs:+1:8: +1:14
|
||||
StorageLive(_5); // scope 0 at $DIR/async_await.rs:+1:5: +1:8
|
||||
_5 = a() -> bb2; // scope 0 at $DIR/async_await.rs:+1:5: +1:8
|
||||
// mir::Constant
|
||||
// + span: $DIR/async_await.rs:15:5: 15:6
|
||||
// + literal: Const { ty: fn() -> impl Future<Output = ()> {a}, val: Value(<ZST>) }
|
||||
}
|
||||
|
||||
bb2: {
|
||||
_4 = <impl Future<Output = ()> as IntoFuture>::into_future(move _5) -> bb3; // scope 0 at $DIR/async_await.rs:+1:8: +1:14
|
||||
// mir::Constant
|
||||
// + span: $DIR/async_await.rs:15:8: 15:14
|
||||
// + literal: Const { ty: fn(impl Future<Output = ()>) -> <impl Future<Output = ()> as IntoFuture>::IntoFuture {<impl Future<Output = ()> as IntoFuture>::into_future}, val: Value(<ZST>) }
|
||||
}
|
||||
|
||||
bb3: {
|
||||
StorageDead(_5); // scope 0 at $DIR/async_await.rs:+1:13: +1:14
|
||||
nop; // scope 0 at $DIR/async_await.rs:+1:8: +1:14
|
||||
(((*(_1.0: &mut [async fn body@$DIR/async_await.rs:14:18: 17:2])) as variant#3).0: impl std::future::Future<Output = ()>) = move _4; // scope 0 at $DIR/async_await.rs:+1:8: +1:14
|
||||
goto -> bb4; // scope 1 at $DIR/async_await.rs:+1:8: +1:14
|
||||
}
|
||||
|
||||
bb4: {
|
||||
StorageLive(_8); // scope 1 at $DIR/async_await.rs:+1:8: +1:14
|
||||
StorageLive(_9); // scope 1 at $DIR/async_await.rs:+1:8: +1:14
|
||||
StorageLive(_10); // scope 2 at $DIR/async_await.rs:+1:8: +1:14
|
||||
StorageLive(_11); // scope 2 at $DIR/async_await.rs:+1:8: +1:14
|
||||
StorageLive(_12); // scope 2 at $DIR/async_await.rs:+1:8: +1:14
|
||||
_12 = &mut (((*(_1.0: &mut [async fn body@$DIR/async_await.rs:14:18: 17:2])) as variant#3).0: impl std::future::Future<Output = ()>); // scope 2 at $DIR/async_await.rs:+1:8: +1:14
|
||||
_11 = &mut (*_12); // scope 2 at $DIR/async_await.rs:+1:8: +1:14
|
||||
_10 = Pin::<&mut impl Future<Output = ()>>::new_unchecked(move _11) -> bb5; // scope 2 at $DIR/async_await.rs:+1:8: +1:14
|
||||
// mir::Constant
|
||||
// + span: $DIR/async_await.rs:15:8: 15:14
|
||||
// + literal: Const { ty: unsafe fn(&mut impl Future<Output = ()>) -> Pin<&mut impl Future<Output = ()>> {Pin::<&mut impl Future<Output = ()>>::new_unchecked}, val: Value(<ZST>) }
|
||||
}
|
||||
|
||||
bb5: {
|
||||
StorageDead(_11); // scope 2 at $DIR/async_await.rs:+1:13: +1:14
|
||||
StorageLive(_13); // scope 2 at $DIR/async_await.rs:+1:5: +1:14
|
||||
StorageLive(_14); // scope 2 at $DIR/async_await.rs:+1:5: +1:14
|
||||
StorageLive(_15); // scope 2 at $DIR/async_await.rs:+1:8: +1:14
|
||||
_15 = _38; // scope 2 at $DIR/async_await.rs:+1:8: +1:14
|
||||
_14 = move _15; // scope 2 at $DIR/async_await.rs:+1:5: +1:14
|
||||
goto -> bb6; // scope 2 at $DIR/async_await.rs:+1:5: +1:14
|
||||
}
|
||||
|
||||
bb6: {
|
||||
_13 = &mut (*_14); // scope 2 at $DIR/async_await.rs:+1:5: +1:14
|
||||
StorageDead(_15); // scope 2 at $DIR/async_await.rs:+1:13: +1:14
|
||||
_9 = <impl Future<Output = ()> as Future>::poll(move _10, move _13) -> bb7; // scope 2 at $DIR/async_await.rs:+1:8: +1:14
|
||||
// mir::Constant
|
||||
// + span: $DIR/async_await.rs:15:8: 15:14
|
||||
// + literal: Const { ty: for<'a, 'b, 'c> fn(Pin<&'a mut impl Future<Output = ()>>, &'b mut Context<'c>) -> Poll<<impl Future<Output = ()> as Future>::Output> {<impl Future<Output = ()> as Future>::poll}, val: Value(<ZST>) }
|
||||
}
|
||||
|
||||
bb7: {
|
||||
StorageDead(_13); // scope 2 at $DIR/async_await.rs:+1:13: +1:14
|
||||
StorageDead(_10); // scope 2 at $DIR/async_await.rs:+1:13: +1:14
|
||||
_16 = discriminant(_9); // scope 1 at $DIR/async_await.rs:+1:8: +1:14
|
||||
switchInt(move _16) -> [0: bb10, 1: bb8, otherwise: bb9]; // scope 1 at $DIR/async_await.rs:+1:8: +1:14
|
||||
}
|
||||
|
||||
bb8: {
|
||||
_8 = const (); // scope 1 at $DIR/async_await.rs:+1:8: +1:14
|
||||
StorageDead(_14); // scope 1 at $DIR/async_await.rs:+1:13: +1:14
|
||||
StorageDead(_12); // scope 1 at $DIR/async_await.rs:+1:13: +1:14
|
||||
StorageDead(_9); // scope 1 at $DIR/async_await.rs:+1:13: +1:14
|
||||
StorageDead(_8); // scope 1 at $DIR/async_await.rs:+1:13: +1:14
|
||||
StorageLive(_19); // scope 1 at $DIR/async_await.rs:+1:8: +1:14
|
||||
StorageLive(_20); // scope 1 at $DIR/async_await.rs:+1:8: +1:14
|
||||
_20 = (); // scope 1 at $DIR/async_await.rs:+1:8: +1:14
|
||||
Deinit(_0); // scope 1 at $DIR/async_await.rs:+1:8: +1:14
|
||||
discriminant(_0) = 1; // scope 1 at $DIR/async_await.rs:+1:8: +1:14
|
||||
discriminant((*(_1.0: &mut [async fn body@$DIR/async_await.rs:14:18: 17:2]))) = 3; // scope 1 at $DIR/async_await.rs:+1:8: +1:14
|
||||
return; // scope 1 at $DIR/async_await.rs:+1:8: +1:14
|
||||
}
|
||||
|
||||
bb9: {
|
||||
unreachable; // scope 1 at $DIR/async_await.rs:+1:8: +1:14
|
||||
}
|
||||
|
||||
bb10: {
|
||||
StorageLive(_17); // scope 1 at $DIR/async_await.rs:+1:5: +1:14
|
||||
_17 = ((_9 as Ready).0: ()); // scope 1 at $DIR/async_await.rs:+1:5: +1:14
|
||||
_3 = _17; // scope 3 at $DIR/async_await.rs:+1:5: +1:14
|
||||
StorageDead(_17); // scope 1 at $DIR/async_await.rs:+1:13: +1:14
|
||||
StorageDead(_14); // scope 1 at $DIR/async_await.rs:+1:13: +1:14
|
||||
StorageDead(_12); // scope 1 at $DIR/async_await.rs:+1:13: +1:14
|
||||
StorageDead(_9); // scope 1 at $DIR/async_await.rs:+1:13: +1:14
|
||||
StorageDead(_8); // scope 1 at $DIR/async_await.rs:+1:13: +1:14
|
||||
goto -> bb12; // scope 0 at $DIR/async_await.rs:+1:13: +1:14
|
||||
}
|
||||
|
||||
bb11: {
|
||||
StorageDead(_20); // scope 1 at $DIR/async_await.rs:+1:13: +1:14
|
||||
_38 = move _19; // scope 1 at $DIR/async_await.rs:+1:8: +1:14
|
||||
StorageDead(_19); // scope 1 at $DIR/async_await.rs:+1:13: +1:14
|
||||
_7 = const (); // scope 1 at $DIR/async_await.rs:+1:8: +1:14
|
||||
goto -> bb4; // scope 1 at $DIR/async_await.rs:+1:8: +1:14
|
||||
}
|
||||
|
||||
bb12: {
|
||||
nop; // scope 0 at $DIR/async_await.rs:+1:13: +1:14
|
||||
goto -> bb13; // scope 0 at $DIR/async_await.rs:+1:14: +1:15
|
||||
}
|
||||
|
||||
bb13: {
|
||||
StorageDead(_4); // scope 0 at $DIR/async_await.rs:+1:14: +1:15
|
||||
StorageDead(_3); // scope 0 at $DIR/async_await.rs:+1:14: +1:15
|
||||
StorageLive(_21); // scope 0 at $DIR/async_await.rs:+2:8: +2:14
|
||||
StorageLive(_22); // scope 0 at $DIR/async_await.rs:+2:5: +2:8
|
||||
_22 = a() -> bb14; // scope 0 at $DIR/async_await.rs:+2:5: +2:8
|
||||
// mir::Constant
|
||||
// + span: $DIR/async_await.rs:16:5: 16:6
|
||||
// + literal: Const { ty: fn() -> impl Future<Output = ()> {a}, val: Value(<ZST>) }
|
||||
}
|
||||
|
||||
bb14: {
|
||||
_21 = <impl Future<Output = ()> as IntoFuture>::into_future(move _22) -> bb15; // scope 0 at $DIR/async_await.rs:+2:8: +2:14
|
||||
// mir::Constant
|
||||
// + span: $DIR/async_await.rs:16:8: 16:14
|
||||
// + literal: Const { ty: fn(impl Future<Output = ()>) -> <impl Future<Output = ()> as IntoFuture>::IntoFuture {<impl Future<Output = ()> as IntoFuture>::into_future}, val: Value(<ZST>) }
|
||||
}
|
||||
|
||||
bb15: {
|
||||
StorageDead(_22); // scope 0 at $DIR/async_await.rs:+2:13: +2:14
|
||||
nop; // scope 0 at $DIR/async_await.rs:+2:8: +2:14
|
||||
(((*(_1.0: &mut [async fn body@$DIR/async_await.rs:14:18: 17:2])) as variant#4).0: impl std::future::Future<Output = ()>) = move _21; // scope 0 at $DIR/async_await.rs:+2:8: +2:14
|
||||
goto -> bb16; // scope 4 at $DIR/async_await.rs:+2:8: +2:14
|
||||
}
|
||||
|
||||
bb16: {
|
||||
StorageLive(_24); // scope 4 at $DIR/async_await.rs:+2:8: +2:14
|
||||
StorageLive(_25); // scope 4 at $DIR/async_await.rs:+2:8: +2:14
|
||||
StorageLive(_26); // scope 5 at $DIR/async_await.rs:+2:8: +2:14
|
||||
StorageLive(_27); // scope 5 at $DIR/async_await.rs:+2:8: +2:14
|
||||
StorageLive(_28); // scope 5 at $DIR/async_await.rs:+2:8: +2:14
|
||||
_28 = &mut (((*(_1.0: &mut [async fn body@$DIR/async_await.rs:14:18: 17:2])) as variant#4).0: impl std::future::Future<Output = ()>); // scope 5 at $DIR/async_await.rs:+2:8: +2:14
|
||||
_27 = &mut (*_28); // scope 5 at $DIR/async_await.rs:+2:8: +2:14
|
||||
_26 = Pin::<&mut impl Future<Output = ()>>::new_unchecked(move _27) -> bb17; // scope 5 at $DIR/async_await.rs:+2:8: +2:14
|
||||
// mir::Constant
|
||||
// + span: $DIR/async_await.rs:16:8: 16:14
|
||||
// + literal: Const { ty: unsafe fn(&mut impl Future<Output = ()>) -> Pin<&mut impl Future<Output = ()>> {Pin::<&mut impl Future<Output = ()>>::new_unchecked}, val: Value(<ZST>) }
|
||||
}
|
||||
|
||||
bb17: {
|
||||
StorageDead(_27); // scope 5 at $DIR/async_await.rs:+2:13: +2:14
|
||||
StorageLive(_29); // scope 5 at $DIR/async_await.rs:+2:5: +2:14
|
||||
StorageLive(_30); // scope 5 at $DIR/async_await.rs:+2:5: +2:14
|
||||
StorageLive(_31); // scope 5 at $DIR/async_await.rs:+2:8: +2:14
|
||||
_31 = _38; // scope 5 at $DIR/async_await.rs:+2:8: +2:14
|
||||
_30 = move _31; // scope 5 at $DIR/async_await.rs:+2:5: +2:14
|
||||
goto -> bb18; // scope 5 at $DIR/async_await.rs:+2:5: +2:14
|
||||
}
|
||||
|
||||
bb18: {
|
||||
_29 = &mut (*_30); // scope 5 at $DIR/async_await.rs:+2:5: +2:14
|
||||
StorageDead(_31); // scope 5 at $DIR/async_await.rs:+2:13: +2:14
|
||||
_25 = <impl Future<Output = ()> as Future>::poll(move _26, move _29) -> bb19; // scope 5 at $DIR/async_await.rs:+2:8: +2:14
|
||||
// mir::Constant
|
||||
// + span: $DIR/async_await.rs:16:8: 16:14
|
||||
// + literal: Const { ty: for<'a, 'b, 'c> fn(Pin<&'a mut impl Future<Output = ()>>, &'b mut Context<'c>) -> Poll<<impl Future<Output = ()> as Future>::Output> {<impl Future<Output = ()> as Future>::poll}, val: Value(<ZST>) }
|
||||
}
|
||||
|
||||
bb19: {
|
||||
StorageDead(_29); // scope 5 at $DIR/async_await.rs:+2:13: +2:14
|
||||
StorageDead(_26); // scope 5 at $DIR/async_await.rs:+2:13: +2:14
|
||||
_32 = discriminant(_25); // scope 4 at $DIR/async_await.rs:+2:8: +2:14
|
||||
switchInt(move _32) -> [0: bb22, 1: bb20, otherwise: bb21]; // scope 4 at $DIR/async_await.rs:+2:8: +2:14
|
||||
}
|
||||
|
||||
bb20: {
|
||||
_24 = const (); // scope 4 at $DIR/async_await.rs:+2:8: +2:14
|
||||
StorageDead(_30); // scope 4 at $DIR/async_await.rs:+2:13: +2:14
|
||||
StorageDead(_28); // scope 4 at $DIR/async_await.rs:+2:13: +2:14
|
||||
StorageDead(_25); // scope 4 at $DIR/async_await.rs:+2:13: +2:14
|
||||
StorageDead(_24); // scope 4 at $DIR/async_await.rs:+2:13: +2:14
|
||||
StorageLive(_35); // scope 4 at $DIR/async_await.rs:+2:8: +2:14
|
||||
StorageLive(_36); // scope 4 at $DIR/async_await.rs:+2:8: +2:14
|
||||
_36 = (); // scope 4 at $DIR/async_await.rs:+2:8: +2:14
|
||||
Deinit(_0); // scope 4 at $DIR/async_await.rs:+2:8: +2:14
|
||||
discriminant(_0) = 1; // scope 4 at $DIR/async_await.rs:+2:8: +2:14
|
||||
discriminant((*(_1.0: &mut [async fn body@$DIR/async_await.rs:14:18: 17:2]))) = 4; // scope 4 at $DIR/async_await.rs:+2:8: +2:14
|
||||
return; // scope 4 at $DIR/async_await.rs:+2:8: +2:14
|
||||
}
|
||||
|
||||
bb21: {
|
||||
unreachable; // scope 4 at $DIR/async_await.rs:+2:8: +2:14
|
||||
}
|
||||
|
||||
bb22: {
|
||||
StorageLive(_33); // scope 4 at $DIR/async_await.rs:+2:5: +2:14
|
||||
_33 = ((_25 as Ready).0: ()); // scope 4 at $DIR/async_await.rs:+2:5: +2:14
|
||||
_37 = _33; // scope 6 at $DIR/async_await.rs:+2:5: +2:14
|
||||
StorageDead(_33); // scope 4 at $DIR/async_await.rs:+2:13: +2:14
|
||||
StorageDead(_30); // scope 4 at $DIR/async_await.rs:+2:13: +2:14
|
||||
StorageDead(_28); // scope 4 at $DIR/async_await.rs:+2:13: +2:14
|
||||
StorageDead(_25); // scope 4 at $DIR/async_await.rs:+2:13: +2:14
|
||||
StorageDead(_24); // scope 4 at $DIR/async_await.rs:+2:13: +2:14
|
||||
goto -> bb24; // scope 0 at $DIR/async_await.rs:+2:13: +2:14
|
||||
}
|
||||
|
||||
bb23: {
|
||||
StorageDead(_36); // scope 4 at $DIR/async_await.rs:+2:13: +2:14
|
||||
_38 = move _35; // scope 4 at $DIR/async_await.rs:+2:8: +2:14
|
||||
StorageDead(_35); // scope 4 at $DIR/async_await.rs:+2:13: +2:14
|
||||
_7 = const (); // scope 4 at $DIR/async_await.rs:+2:8: +2:14
|
||||
goto -> bb16; // scope 4 at $DIR/async_await.rs:+2:8: +2:14
|
||||
}
|
||||
|
||||
bb24: {
|
||||
nop; // scope 0 at $DIR/async_await.rs:+2:13: +2:14
|
||||
goto -> bb25; // scope 0 at $DIR/async_await.rs:+3:1: +3:2
|
||||
}
|
||||
|
||||
bb25: {
|
||||
StorageDead(_21); // scope 0 at $DIR/async_await.rs:+3:1: +3:2
|
||||
goto -> bb26; // scope 0 at $DIR/async_await.rs:+3:1: +3:2
|
||||
}
|
||||
|
||||
bb26: {
|
||||
Deinit(_0); // scope 0 at $DIR/async_await.rs:+3:2: +3:2
|
||||
((_0 as Ready).0: ()) = move _37; // scope 0 at $DIR/async_await.rs:+3:2: +3:2
|
||||
discriminant(_0) = 0; // scope 0 at $DIR/async_await.rs:+3:2: +3:2
|
||||
discriminant((*(_1.0: &mut [async fn body@$DIR/async_await.rs:14:18: 17:2]))) = 1; // scope 0 at $DIR/async_await.rs:+3:2: +3:2
|
||||
return; // scope 0 at $DIR/async_await.rs:+3:2: +3:2
|
||||
}
|
||||
|
||||
bb27: {
|
||||
StorageLive(_3); // scope 0 at $DIR/async_await.rs:+0:18: +3:2
|
||||
StorageLive(_4); // scope 0 at $DIR/async_await.rs:+0:18: +3:2
|
||||
StorageLive(_19); // scope 0 at $DIR/async_await.rs:+0:18: +3:2
|
||||
StorageLive(_20); // scope 0 at $DIR/async_await.rs:+0:18: +3:2
|
||||
_19 = move _2; // scope 0 at $DIR/async_await.rs:+0:18: +3:2
|
||||
goto -> bb11; // scope 0 at $DIR/async_await.rs:+0:18: +3:2
|
||||
}
|
||||
|
||||
bb28: {
|
||||
StorageLive(_21); // scope 0 at $DIR/async_await.rs:+0:18: +3:2
|
||||
StorageLive(_35); // scope 0 at $DIR/async_await.rs:+0:18: +3:2
|
||||
StorageLive(_36); // scope 0 at $DIR/async_await.rs:+0:18: +3:2
|
||||
_35 = move _2; // scope 0 at $DIR/async_await.rs:+0:18: +3:2
|
||||
goto -> bb23; // scope 0 at $DIR/async_await.rs:+0:18: +3:2
|
||||
}
|
||||
|
||||
bb29: {
|
||||
assert(const false, "`async fn` resumed after completion") -> bb29; // scope 0 at $DIR/async_await.rs:+0:18: +3:2
|
||||
}
|
||||
|
||||
bb30: {
|
||||
unreachable; // scope 0 at $DIR/async_await.rs:+0:18: +3:2
|
||||
}
|
||||
}
|
||||
17
tests/mir-opt/building/async_await.rs
Normal file
17
tests/mir-opt/building/async_await.rs
Normal file
@ -0,0 +1,17 @@
|
||||
// This test makes sure that the generator MIR pass eliminates all calls to
|
||||
// `get_context`, and that the MIR argument type for an async fn and all locals
|
||||
// related to `yield` are `&mut Context`, and its return type is `Poll`.
|
||||
|
||||
// edition:2018
|
||||
// compile-flags: -C panic=abort
|
||||
|
||||
#![crate_type = "lib"]
|
||||
|
||||
// EMIT_MIR async_await.a-{closure#0}.generator_resume.0.mir
|
||||
async fn a() {}
|
||||
|
||||
// EMIT_MIR async_await.b-{closure#0}.generator_resume.0.mir
|
||||
pub async fn b() {
|
||||
a().await;
|
||||
a().await
|
||||
}
|
||||
Loading…
Reference in New Issue
Block a user