bjoernager/rust
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Auto merge of #95576 - DrMeepster:box_erasure, r=oli-obk

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Remove dereferencing of Box from codegen

Through #94043, #94414, #94873, and #95328, I've been fixing issues caused by Box being treated like a pointer when it is not a pointer. However, these PRs just introduced special cases for Box. This PR removes those special cases and instead transforms a deref of Box into a deref of the pointer it contains.

Hopefully, this is the end of the Box<T, A> ICEs.
This commit is contained in:
bors 2022-06-21 11:00:39 +00:00
commit a25b1315ee
18 changed files with 477 additions and 162 deletions
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13
compiler/rustc_mir_dataflow/src/elaborate_drops.rs
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@ -410,7 +410,18 @@ where
fn open_drop_for_box(&mut self, adt: ty::AdtDef<'tcx>, substs: SubstsRef<'tcx>) -> BasicBlock {
debug!("open_drop_for_box({:?}, {:?}, {:?})", self, adt, substs);
let interior = self.tcx().mk_place_deref(self.place);
// drop glue is sent straight to codegen
// box cannot be directly dereferenced
let unique_ty = adt.non_enum_variant().fields[0].ty(self.tcx(), substs);
let nonnull_ty =
unique_ty.ty_adt_def().unwrap().non_enum_variant().fields[0].ty(self.tcx(), substs);
let ptr_ty = self.tcx().mk_imm_ptr(substs[0].expect_ty());
let unique_place = self.tcx().mk_place_field(self.place, Field::new(0), unique_ty);
let nonnull_place = self.tcx().mk_place_field(unique_place, Field::new(0), nonnull_ty);
let ptr_place = self.tcx().mk_place_field(nonnull_place, Field::new(0), ptr_ty);
let interior = self.tcx().mk_place_deref(ptr_place);
let interior_path = self.elaborator.deref_subpath(self.path);
let succ = self.box_free_block(adt, substs, self.succ, self.unwind);