diff --git a/compiler/rustc_middle/src/mir/tcx.rs b/compiler/rustc_middle/src/mir/tcx.rs index af23c8b2ea76d..862f78d725982 100644 --- a/compiler/rustc_middle/src/mir/tcx.rs +++ b/compiler/rustc_middle/src/mir/tcx.rs @@ -86,6 +86,14 @@ impl<'tcx> PlaceTy<'tcx> { } } + pub fn multi_projection_ty( + self, + tcx: TyCtxt<'tcx>, + elems: &[PlaceElem<'tcx>], + ) -> PlaceTy<'tcx> { + elems.iter().fold(self, |place_ty, &elem| place_ty.projection_ty(tcx, elem)) + } + /// Convenience wrapper around `projection_ty_core` for /// `PlaceElem`, where we can just use the `Ty` that is already /// stored inline on field projection elems. @@ -167,11 +175,7 @@ impl<'tcx> Place<'tcx> { where D: HasLocalDecls<'tcx>, { - projection - .iter() - .fold(PlaceTy::from_ty(local_decls.local_decls()[local].ty), |place_ty, &elem| { - place_ty.projection_ty(tcx, elem) - }) + PlaceTy::from_ty(local_decls.local_decls()[local].ty).multi_projection_ty(tcx, projection) } pub fn ty(&self, local_decls: &D, tcx: TyCtxt<'tcx>) -> PlaceTy<'tcx> diff --git a/compiler/rustc_mir_transform/src/elaborate_drop.rs b/compiler/rustc_mir_transform/src/elaborate_drop.rs index ed4903017f353..2de55e38052e3 100644 --- a/compiler/rustc_mir_transform/src/elaborate_drop.rs +++ b/compiler/rustc_mir_transform/src/elaborate_drop.rs @@ -89,6 +89,7 @@ pub(crate) trait DropElaborator<'a, 'tcx>: fmt::Debug { // Accessors + fn patch_ref(&self) -> &MirPatch<'tcx>; fn patch(&mut self) -> &mut MirPatch<'tcx>; fn body(&self) -> &'a Body<'tcx>; fn tcx(&self) -> TyCtxt<'tcx>; @@ -180,7 +181,14 @@ where { #[instrument(level = "trace", skip(self), ret)] fn place_ty(&self, place: Place<'tcx>) -> Ty<'tcx> { - place.ty(self.elaborator.body(), self.tcx()).ty + if place.local < self.elaborator.body().local_decls.next_index() { + place.ty(self.elaborator.body(), self.tcx()).ty + } else { + // We don't have a slice with all the locals, since some are in the patch. + tcx::PlaceTy::from_ty(self.elaborator.patch_ref().local_ty(place.local)) + .multi_projection_ty(self.elaborator.tcx(), place.projection) + .ty + } } fn tcx(&self) -> TyCtxt<'tcx> { @@ -410,12 +418,26 @@ where let unique_place = self.tcx().mk_place_field(self.place, FieldIdx::ZERO, unique_ty); let nonnull_place = self.tcx().mk_place_field(unique_place, FieldIdx::ZERO, nonnull_ty); - let ptr_place = self.tcx().mk_place_field(nonnull_place, FieldIdx::ZERO, ptr_ty); - let interior = self.tcx().mk_place_deref(ptr_place); + let ptr_local = self.new_temp(ptr_ty); + + let interior = self.tcx().mk_place_deref(Place::from(ptr_local)); let interior_path = self.elaborator.deref_subpath(self.path); - self.drop_subpath(interior, interior_path, succ, unwind) + let do_drop_bb = self.drop_subpath(interior, interior_path, succ, unwind); + + let setup_bbd = BasicBlockData { + statements: vec![self.assign( + Place::from(ptr_local), + Rvalue::Cast(CastKind::Transmute, Operand::Copy(nonnull_place), ptr_ty), + )], + terminator: Some(Terminator { + kind: TerminatorKind::Goto { target: do_drop_bb }, + source_info: self.source_info, + }), + is_cleanup: unwind.is_cleanup(), + }; + self.elaborator.patch().new_block(setup_bbd) } #[instrument(level = "debug", ret)] diff --git a/compiler/rustc_mir_transform/src/elaborate_drops.rs b/compiler/rustc_mir_transform/src/elaborate_drops.rs index 2d74fcff415ed..ab6aafab446bb 100644 --- a/compiler/rustc_mir_transform/src/elaborate_drops.rs +++ b/compiler/rustc_mir_transform/src/elaborate_drops.rs @@ -138,6 +138,10 @@ impl InitializationData<'_, '_> { impl<'a, 'tcx> DropElaborator<'a, 'tcx> for ElaborateDropsCtxt<'a, 'tcx> { type Path = MovePathIndex; + fn patch_ref(&self) -> &MirPatch<'tcx> { + &self.patch + } + fn patch(&mut self) -> &mut MirPatch<'tcx> { &mut self.patch } diff --git a/compiler/rustc_mir_transform/src/patch.rs b/compiler/rustc_mir_transform/src/patch.rs index 72cd9c224f648..b4f6fa514a487 100644 --- a/compiler/rustc_mir_transform/src/patch.rs +++ b/compiler/rustc_mir_transform/src/patch.rs @@ -166,6 +166,14 @@ impl<'tcx> MirPatch<'tcx> { Local::new(index) } + /// Returns the type of a local that's newly-added in the patch. + pub(crate) fn local_ty(&self, local: Local) -> Ty<'tcx> { + let local = local.as_usize(); + assert!(local < self.next_local); + let new_local_idx = self.new_locals.len() - (self.next_local - local); + self.new_locals[new_local_idx].ty + } + pub(crate) fn new_block(&mut self, data: BasicBlockData<'tcx>) -> BasicBlock { let block = BasicBlock::new(self.patch_map.len()); debug!("MirPatch: new_block: {:?}: {:?}", block, data); diff --git a/compiler/rustc_mir_transform/src/shim.rs b/compiler/rustc_mir_transform/src/shim.rs index e8d86bad98735..34074a84e28b6 100644 --- a/compiler/rustc_mir_transform/src/shim.rs +++ b/compiler/rustc_mir_transform/src/shim.rs @@ -350,6 +350,9 @@ impl fmt::Debug for DropShimElaborator<'_, '_> { impl<'a, 'tcx> DropElaborator<'a, 'tcx> for DropShimElaborator<'a, 'tcx> { type Path = (); + fn patch_ref(&self) -> &MirPatch<'tcx> { + &self.patch + } fn patch(&mut self) -> &mut MirPatch<'tcx> { &mut self.patch } diff --git a/tests/mir-opt/box_expr.main.ElaborateDrops.diff b/tests/mir-opt/box_expr.main.ElaborateDrops.diff index ec40fac2894eb..827dc6ac7aefe 100644 --- a/tests/mir-opt/box_expr.main.ElaborateDrops.diff +++ b/tests/mir-opt/box_expr.main.ElaborateDrops.diff @@ -12,6 +12,7 @@ let mut _7: std::boxed::Box; + let mut _8: &mut std::boxed::Box; + let mut _9: (); ++ let mut _10: *const S; scope 1 { debug x => _1; } @@ -68,7 +69,7 @@ bb8 (cleanup): { - drop(_5) -> [return: bb9, unwind terminate(cleanup)]; -+ goto -> bb11; ++ goto -> bb12; } bb9 (cleanup): { @@ -82,6 +83,11 @@ + + bb11 (cleanup): { + goto -> bb10; ++ } ++ ++ bb12 (cleanup): { ++ _10 = copy ((_5.0: std::ptr::Unique).0: std::ptr::NonNull) as *const S (Transmute); ++ goto -> bb11; } } diff --git a/tests/mir-opt/box_partial_move.maybe_move.ElaborateDrops.diff b/tests/mir-opt/box_partial_move.maybe_move.ElaborateDrops.diff new file mode 100644 index 0000000000000..f090795e88656 --- /dev/null +++ b/tests/mir-opt/box_partial_move.maybe_move.ElaborateDrops.diff @@ -0,0 +1,94 @@ +- // MIR for `maybe_move` before ElaborateDrops ++ // MIR for `maybe_move` after ElaborateDrops + + fn maybe_move(_1: bool, _2: Box) -> Option { + debug cond => _1; + debug thing => _2; + let mut _0: std::option::Option; + let mut _3: bool; + let mut _4: std::string::String; ++ let mut _5: bool; ++ let mut _6: &mut std::boxed::Box; ++ let mut _7: (); ++ let mut _8: &mut std::boxed::Box; ++ let mut _9: (); ++ let mut _10: *const std::string::String; + + bb0: { ++ _5 = const false; ++ _5 = const true; + StorageLive(_3); + _3 = copy _1; + switchInt(move _3) -> [0: bb3, otherwise: bb1]; + } + + bb1: { + StorageLive(_4); ++ _5 = const false; + _4 = move (*_2); + _0 = Option::::Some(move _4); +- drop(_4) -> [return: bb2, unwind: bb6]; ++ goto -> bb2; + } + + bb2: { + StorageDead(_4); + goto -> bb4; + } + + bb3: { + _0 = Option::::None; + goto -> bb4; + } + + bb4: { + StorageDead(_3); +- drop(_2) -> [return: bb5, unwind continue]; ++ goto -> bb14; + } + + bb5: { + return; + } + + bb6 (cleanup): { +- drop(_2) -> [return: bb7, unwind terminate(cleanup)]; ++ goto -> bb7; + } + + bb7 (cleanup): { + resume; ++ } ++ ++ bb8: { ++ goto -> bb5; ++ } ++ ++ bb9: { ++ _6 = &mut _2; ++ _7 = as Drop>::drop(move _6) -> [return: bb8, unwind: bb7]; ++ } ++ ++ bb10 (cleanup): { ++ _8 = &mut _2; ++ _9 = as Drop>::drop(move _8) -> [return: bb7, unwind terminate(cleanup)]; ++ } ++ ++ bb11: { ++ goto -> bb13; ++ } ++ ++ bb12: { ++ drop((*_10)) -> [return: bb9, unwind: bb10]; ++ } ++ ++ bb13: { ++ switchInt(copy _5) -> [0: bb9, otherwise: bb12]; ++ } ++ ++ bb14: { ++ _10 = copy ((_2.0: std::ptr::Unique).0: std::ptr::NonNull) as *const std::string::String (Transmute); ++ goto -> bb11; + } + } + diff --git a/tests/mir-opt/box_partial_move.rs b/tests/mir-opt/box_partial_move.rs new file mode 100644 index 0000000000000..5cbd242986f52 --- /dev/null +++ b/tests/mir-opt/box_partial_move.rs @@ -0,0 +1,17 @@ +//@ test-mir-pass: ElaborateDrops +//@ needs-unwind + +#![feature(rustc_attrs, liballoc_internals)] + +// EMIT_MIR box_partial_move.maybe_move.ElaborateDrops.diff +fn maybe_move(cond: bool, thing: Box) -> Option { + // CHECK-LABEL: fn maybe_move( + // CHECK: let mut [[PTR:_[0-9]+]]: *const std::string::String; + // CHECK: [[PTR]] = copy ((_2.0: std::ptr::Unique).0: std::ptr::NonNull) as *const std::string::String (Transmute); + // CHECK: drop((*[[PTR]])) + if cond { Some(*thing) } else { None } +} + +fn main() { + maybe_move(false, Box::new("hello".to_string())); +}