diff options
Diffstat (limited to 'compiler')
| -rw-r--r-- | compiler/rustc_mir_build/src/build/expr/as_place.rs | 79 | ||||
| -rw-r--r-- | compiler/rustc_mir_build/src/build/expr/as_rvalue.rs | 1 | ||||
| -rw-r--r-- | compiler/rustc_mir_build/src/build/expr/category.rs | 1 | ||||
| -rw-r--r-- | compiler/rustc_mir_build/src/build/expr/into.rs | 1 | ||||
| -rw-r--r-- | compiler/rustc_mir_build/src/thir/cx/expr.rs | 132 | ||||
| -rw-r--r-- | compiler/rustc_mir_build/src/thir/cx/mod.rs | 4 | ||||
| -rw-r--r-- | compiler/rustc_mir_build/src/thir/mod.rs | 8 |
7 files changed, 108 insertions, 118 deletions
diff --git a/compiler/rustc_mir_build/src/build/expr/as_place.rs b/compiler/rustc_mir_build/src/build/expr/as_place.rs index b94346fa439..3f06aa1b131 100644 --- a/compiler/rustc_mir_build/src/build/expr/as_place.rs +++ b/compiler/rustc_mir_build/src/build/expr/as_place.rs @@ -160,6 +160,30 @@ impl<'a, 'tcx> Builder<'a, 'tcx> { expr_span, source_info, ), + ExprKind::UpvarRef { closure_def_id, var_hir_id } => { + let capture = this + .hir + .typeck_results + .closure_captures + .get(&closure_def_id) + .and_then(|captures| captures.get_full(&var_hir_id)); + + if capture.is_none() { + if !this.hir.tcx().features().capture_disjoint_fields { + bug!( + "No associated capture found for {:?} even though \ + capture_disjoint_fields isn't enabled", + expr.kind + ) + } + // FIXME(project-rfc-2229#24): Handle this case properly + } + + // Unwrap until the FIXME has been resolved + let (capture_index, _, upvar_id) = capture.unwrap(); + this.lower_closure_capture(block, capture_index, *upvar_id) + } + ExprKind::SelfRef => block.and(PlaceBuilder::from(Local::new(1))), ExprKind::VarRef { id } => { let place_builder = if this.is_bound_var_in_guard(id) { @@ -270,6 +294,61 @@ impl<'a, 'tcx> Builder<'a, 'tcx> { } } + /// Lower a closure/generator capture by representing it as a field + /// access within the desugared closure/generator. + /// + /// `capture_index` is the index of the capture within the desugared + /// closure/generator. + fn lower_closure_capture( + &mut self, + block: BasicBlock, + capture_index: usize, + upvar_id: ty::UpvarId, + ) -> BlockAnd<PlaceBuilder<'tcx>> { + let closure_ty = self + .hir + .typeck_results() + .node_type(self.hir.tcx().hir().local_def_id_to_hir_id(upvar_id.closure_expr_id)); + + // Captures are represented using fields inside a structure. + // This represents accessing self in the closure structure + let mut place_builder = PlaceBuilder::from(Local::new(1)); + + // In case of Fn/FnMut closures we must deref to access the fields + // Generators are considered FnOnce, so we ignore this step for them. + if let ty::Closure(_, closure_substs) = closure_ty.kind() { + match self.hir.infcx().closure_kind(closure_substs).unwrap() { + ty::ClosureKind::Fn | ty::ClosureKind::FnMut => { + place_builder = place_builder.deref(); + } + ty::ClosureKind::FnOnce => {} + } + } + + let substs = match closure_ty.kind() { + ty::Closure(_, substs) => ty::UpvarSubsts::Closure(substs), + ty::Generator(_, substs, _) => ty::UpvarSubsts::Generator(substs), + _ => bug!("Lowering capture for non-closure type {:?}", closure_ty) + }; + + // Access the capture by accessing the field within the Closure struct. + // + // We must have inferred the capture types since we are building MIR, therefore + // it's safe to call `upvar_tys` and we can unwrap here because + // we know that the capture exists and is the `capture_index`-th capture. + let var_ty = substs.upvar_tys().nth(capture_index).unwrap(); + place_builder = place_builder.field(Field::new(capture_index), var_ty); + + // If the variable is captured via ByRef(Immutable/Mutable) Borrow, + // we need to deref it + match self.hir.typeck_results.upvar_capture(upvar_id) { + ty::UpvarCapture::ByRef(_) => { + block.and(place_builder.deref()) + } + ty::UpvarCapture::ByValue(_) => block.and(place_builder), + } + } + /// Lower an index expression /// /// This has two complications; diff --git a/compiler/rustc_mir_build/src/build/expr/as_rvalue.rs b/compiler/rustc_mir_build/src/build/expr/as_rvalue.rs index 2853bf887fa..106ec1631e1 100644 --- a/compiler/rustc_mir_build/src/build/expr/as_rvalue.rs +++ b/compiler/rustc_mir_build/src/build/expr/as_rvalue.rs @@ -251,6 +251,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> { | ExprKind::Index { .. } | ExprKind::VarRef { .. } | ExprKind::SelfRef + | ExprKind::UpvarRef { .. } | ExprKind::Break { .. } | ExprKind::Continue { .. } | ExprKind::Return { .. } diff --git a/compiler/rustc_mir_build/src/build/expr/category.rs b/compiler/rustc_mir_build/src/build/expr/category.rs index ac5cf187aa0..925c698111d 100644 --- a/compiler/rustc_mir_build/src/build/expr/category.rs +++ b/compiler/rustc_mir_build/src/build/expr/category.rs @@ -39,6 +39,7 @@ impl Category { | ExprKind::Deref { .. } | ExprKind::Index { .. } | ExprKind::SelfRef + | ExprKind::UpvarRef { .. } | ExprKind::VarRef { .. } | ExprKind::PlaceTypeAscription { .. } | ExprKind::ValueTypeAscription { .. } => Some(Category::Place), diff --git a/compiler/rustc_mir_build/src/build/expr/into.rs b/compiler/rustc_mir_build/src/build/expr/into.rs index 9dc596a345f..9ff1134e675 100644 --- a/compiler/rustc_mir_build/src/build/expr/into.rs +++ b/compiler/rustc_mir_build/src/build/expr/into.rs @@ -401,6 +401,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> { // Avoid creating a temporary ExprKind::VarRef { .. } | ExprKind::SelfRef + | ExprKind::UpvarRef { .. } | ExprKind::PlaceTypeAscription { .. } | ExprKind::ValueTypeAscription { .. } => { debug_assert!(Category::of(&expr.kind) == Some(Category::Place)); diff --git a/compiler/rustc_mir_build/src/thir/cx/expr.rs b/compiler/rustc_mir_build/src/thir/cx/expr.rs index 47c0400533b..e404afeb698 100644 --- a/compiler/rustc_mir_build/src/thir/cx/expr.rs +++ b/compiler/rustc_mir_build/src/thir/cx/expr.rs @@ -880,130 +880,26 @@ fn convert_path_expr<'a, 'tcx>( ExprKind::Deref { arg: Expr { ty, temp_lifetime, span: expr.span, kind }.to_ref() } } - Res::Local(var_hir_id) => convert_var(cx, expr, var_hir_id), + Res::Local(var_hir_id) => convert_var(cx, var_hir_id), _ => span_bug!(expr.span, "res `{:?}` not yet implemented", res), } } -fn convert_var<'tcx>( - cx: &mut Cx<'_, 'tcx>, - expr: &'tcx hir::Expr<'tcx>, - var_hir_id: hir::HirId, -) -> ExprKind<'tcx> { - let upvar_index = cx - .typeck_results() - .closure_captures - .get(&cx.body_owner) - .and_then(|upvars| upvars.get_full(&var_hir_id).map(|(i, _, _)| i)); - - debug!( - "convert_var({:?}): upvar_index={:?}, body_owner={:?}", - var_hir_id, upvar_index, cx.body_owner - ); - - let temp_lifetime = cx.region_scope_tree.temporary_scope(expr.hir_id.local_id); - - match upvar_index { - None => ExprKind::VarRef { id: var_hir_id }, +fn convert_var<'tcx>(cx: &mut Cx<'_, 'tcx>, var_hir_id: hir::HirId) -> ExprKind<'tcx> { + // We want upvars here not captures. + // Captures will be handled in MIR. + let is_upvar = cx + .tcx + .upvars_mentioned(cx.body_owner) + .map_or(false, |upvars| upvars.contains_key(&var_hir_id)); - Some(upvar_index) => { - let closure_def_id = cx.body_owner; - let upvar_id = ty::UpvarId { - var_path: ty::UpvarPath { hir_id: var_hir_id }, - closure_expr_id: closure_def_id.expect_local(), - }; - let var_ty = cx.typeck_results().node_type(var_hir_id); + debug!("convert_var({:?}): is_upvar={}, body_owner={:?}", var_hir_id, is_upvar, cx.body_owner); - // FIXME free regions in closures are not right - let closure_ty = cx - .typeck_results() - .node_type(cx.tcx.hir().local_def_id_to_hir_id(upvar_id.closure_expr_id)); - - // FIXME we're just hard-coding the idea that the - // signature will be &self or &mut self and hence will - // have a bound region with number 0 - let region = ty::ReFree(ty::FreeRegion { - scope: closure_def_id, - bound_region: ty::BoundRegion::BrAnon(0), - }); - let region = cx.tcx.mk_region(region); - - let self_expr = if let ty::Closure(_, closure_substs) = closure_ty.kind() { - match cx.infcx.closure_kind(closure_substs).unwrap() { - ty::ClosureKind::Fn => { - let ref_closure_ty = cx.tcx.mk_ref( - region, - ty::TypeAndMut { ty: closure_ty, mutbl: hir::Mutability::Not }, - ); - Expr { - ty: closure_ty, - temp_lifetime, - span: expr.span, - kind: ExprKind::Deref { - arg: Expr { - ty: ref_closure_ty, - temp_lifetime, - span: expr.span, - kind: ExprKind::SelfRef, - } - .to_ref(), - }, - } - } - ty::ClosureKind::FnMut => { - let ref_closure_ty = cx.tcx.mk_ref( - region, - ty::TypeAndMut { ty: closure_ty, mutbl: hir::Mutability::Mut }, - ); - Expr { - ty: closure_ty, - temp_lifetime, - span: expr.span, - kind: ExprKind::Deref { - arg: Expr { - ty: ref_closure_ty, - temp_lifetime, - span: expr.span, - kind: ExprKind::SelfRef, - } - .to_ref(), - }, - } - } - ty::ClosureKind::FnOnce => Expr { - ty: closure_ty, - temp_lifetime, - span: expr.span, - kind: ExprKind::SelfRef, - }, - } - } else { - Expr { ty: closure_ty, temp_lifetime, span: expr.span, kind: ExprKind::SelfRef } - }; - - // at this point we have `self.n`, which loads up the upvar - let field_kind = - ExprKind::Field { lhs: self_expr.to_ref(), name: Field::new(upvar_index) }; - - // ...but the upvar might be an `&T` or `&mut T` capture, at which - // point we need an implicit deref - match cx.typeck_results().upvar_capture(upvar_id) { - ty::UpvarCapture::ByValue(_) => field_kind, - ty::UpvarCapture::ByRef(borrow) => ExprKind::Deref { - arg: Expr { - temp_lifetime, - ty: cx.tcx.mk_ref( - borrow.region, - ty::TypeAndMut { ty: var_ty, mutbl: borrow.kind.to_mutbl_lossy() }, - ), - span: expr.span, - kind: field_kind, - } - .to_ref(), - }, - } - } + if is_upvar { + ExprKind::UpvarRef { closure_def_id: cx.body_owner, var_hir_id } + } else { + ExprKind::VarRef { id: var_hir_id } } } @@ -1102,7 +998,7 @@ fn capture_upvar<'tcx>( temp_lifetime, ty: var_ty, span: closure_expr.span, - kind: convert_var(cx, closure_expr, var_hir_id), + kind: convert_var(cx, var_hir_id), }; match upvar_capture { ty::UpvarCapture::ByValue(_) => captured_var.to_ref(), diff --git a/compiler/rustc_mir_build/src/thir/cx/mod.rs b/compiler/rustc_mir_build/src/thir/cx/mod.rs index cf42fee873e..465808cea9d 100644 --- a/compiler/rustc_mir_build/src/thir/cx/mod.rs +++ b/compiler/rustc_mir_build/src/thir/cx/mod.rs @@ -186,6 +186,10 @@ impl<'a, 'tcx> Cx<'a, 'tcx> { ty.needs_drop(self.tcx, self.param_env) } + crate fn infcx(&self) -> &'a InferCtxt<'a, 'tcx> { + self.infcx + } + crate fn tcx(&self) -> TyCtxt<'tcx> { self.tcx } diff --git a/compiler/rustc_mir_build/src/thir/mod.rs b/compiler/rustc_mir_build/src/thir/mod.rs index f2a2ef0d8f2..d577ec6734f 100644 --- a/compiler/rustc_mir_build/src/thir/mod.rs +++ b/compiler/rustc_mir_build/src/thir/mod.rs @@ -211,6 +211,14 @@ crate enum ExprKind<'tcx> { VarRef { id: hir::HirId, }, + /// Used to represent upvars mentioned in a closure/generator + UpvarRef { + /// DefId of the closure/generator + closure_def_id: DefId, + + /// HirId of the root variable + var_hir_id: hir::HirId, + }, /// first argument, used for self in a closure SelfRef, Borrow { |