diff options
Diffstat (limited to 'compiler/rustc_mir_transform/src')
| -rw-r--r-- | compiler/rustc_mir_transform/src/add_subtyping_projections.rs | 70 | ||||
| -rw-r--r-- | compiler/rustc_mir_transform/src/gvn.rs | 1 | ||||
| -rw-r--r-- | compiler/rustc_mir_transform/src/inline.rs | 24 | ||||
| -rw-r--r-- | compiler/rustc_mir_transform/src/lib.rs | 2 | ||||
| -rw-r--r-- | compiler/rustc_mir_transform/src/reveal_all.rs | 4 |
5 files changed, 97 insertions, 4 deletions
diff --git a/compiler/rustc_mir_transform/src/add_subtyping_projections.rs b/compiler/rustc_mir_transform/src/add_subtyping_projections.rs new file mode 100644 index 00000000000..e5be7c0ca76 --- /dev/null +++ b/compiler/rustc_mir_transform/src/add_subtyping_projections.rs @@ -0,0 +1,70 @@ +use crate::MirPass; +use rustc_index::IndexVec; +use rustc_middle::mir::patch::MirPatch; +use rustc_middle::mir::visit::MutVisitor; +use rustc_middle::mir::*; +use rustc_middle::ty::TyCtxt; + +pub struct Subtyper; + +pub struct SubTypeChecker<'a, 'tcx> { + tcx: TyCtxt<'tcx>, + patcher: MirPatch<'tcx>, + local_decls: &'a IndexVec<Local, LocalDecl<'tcx>>, +} + +impl<'a, 'tcx> MutVisitor<'tcx> for SubTypeChecker<'a, 'tcx> { + fn tcx(&self) -> TyCtxt<'tcx> { + self.tcx + } + + fn visit_assign( + &mut self, + place: &mut Place<'tcx>, + rvalue: &mut Rvalue<'tcx>, + location: Location, + ) { + // We don't need to do anything for deref temps as they are + // not part of the source code, but used for desugaring purposes. + if self.local_decls[place.local].is_deref_temp() { + return; + } + let mut place_ty = place.ty(self.local_decls, self.tcx).ty; + let mut rval_ty = rvalue.ty(self.local_decls, self.tcx); + // Not erasing this causes `Free Regions` errors in validator, + // when rval is `ReStatic`. + rval_ty = self.tcx.erase_regions_ty(rval_ty); + place_ty = self.tcx.erase_regions(place_ty); + if place_ty != rval_ty { + let temp = self + .patcher + .new_temp(rval_ty, self.local_decls[place.as_ref().local].source_info.span); + let new_place = Place::from(temp); + self.patcher.add_assign(location, new_place, rvalue.clone()); + let subtyped = new_place.project_deeper(&[ProjectionElem::Subtype(place_ty)], self.tcx); + *rvalue = Rvalue::Use(Operand::Move(subtyped)); + } + } +} + +// Aim here is to do this kind of transformation: +// +// let place: place_ty = rval; +// // gets transformed to +// let temp: rval_ty = rval; +// let place: place_ty = temp as place_ty; +pub fn subtype_finder<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) { + let patch = MirPatch::new(body); + let mut checker = SubTypeChecker { tcx, patcher: patch, local_decls: &body.local_decls }; + + for (bb, data) in body.basic_blocks.as_mut_preserves_cfg().iter_enumerated_mut() { + checker.visit_basic_block_data(bb, data); + } + checker.patcher.apply(body); +} + +impl<'tcx> MirPass<'tcx> for Subtyper { + fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) { + subtype_finder(tcx, body); + } +} diff --git a/compiler/rustc_mir_transform/src/gvn.rs b/compiler/rustc_mir_transform/src/gvn.rs index 449bade3322..56bdc5a171a 100644 --- a/compiler/rustc_mir_transform/src/gvn.rs +++ b/compiler/rustc_mir_transform/src/gvn.rs @@ -306,6 +306,7 @@ impl<'body, 'tcx> VnState<'body, 'tcx> { } ProjectionElem::Downcast(name, index) => ProjectionElem::Downcast(name, index), ProjectionElem::OpaqueCast(ty) => ProjectionElem::OpaqueCast(ty), + ProjectionElem::Subtype(ty) => ProjectionElem::Subtype(ty), }; value = self.insert(Value::Projection(value, proj)); } diff --git a/compiler/rustc_mir_transform/src/inline.rs b/compiler/rustc_mir_transform/src/inline.rs index ebd61f8ad95..b53e0852c09 100644 --- a/compiler/rustc_mir_transform/src/inline.rs +++ b/compiler/rustc_mir_transform/src/inline.rs @@ -218,7 +218,13 @@ impl<'tcx> Inliner<'tcx> { // Normally, this shouldn't be required, but trait normalization failure can create a // validation ICE. let output_type = callee_body.return_ty(); - if !util::is_subtype(self.tcx, self.param_env, output_type, destination_ty) { + if !util::relate_types( + self.tcx, + self.param_env, + ty::Variance::Covariant, + output_type, + destination_ty, + ) { trace!(?output_type, ?destination_ty); return Err("failed to normalize return type"); } @@ -248,7 +254,13 @@ impl<'tcx> Inliner<'tcx> { self_arg_ty.into_iter().chain(arg_tuple_tys).zip(callee_body.args_iter()) { let input_type = callee_body.local_decls[input].ty; - if !util::is_subtype(self.tcx, self.param_env, input_type, arg_ty) { + if !util::relate_types( + self.tcx, + self.param_env, + ty::Variance::Covariant, + input_type, + arg_ty, + ) { trace!(?arg_ty, ?input_type); return Err("failed to normalize tuple argument type"); } @@ -257,7 +269,13 @@ impl<'tcx> Inliner<'tcx> { for (arg, input) in args.iter().zip(callee_body.args_iter()) { let input_type = callee_body.local_decls[input].ty; let arg_ty = arg.ty(&caller_body.local_decls, self.tcx); - if !util::is_subtype(self.tcx, self.param_env, input_type, arg_ty) { + if !util::relate_types( + self.tcx, + self.param_env, + ty::Variance::Covariant, + input_type, + arg_ty, + ) { trace!(?arg_ty, ?input_type); return Err("failed to normalize argument type"); } diff --git a/compiler/rustc_mir_transform/src/lib.rs b/compiler/rustc_mir_transform/src/lib.rs index 754f2ee8376..c0a09b7a761 100644 --- a/compiler/rustc_mir_transform/src/lib.rs +++ b/compiler/rustc_mir_transform/src/lib.rs @@ -54,6 +54,7 @@ mod check_packed_ref; pub mod check_unsafety; mod remove_place_mention; // This pass is public to allow external drivers to perform MIR cleanup +mod add_subtyping_projections; pub mod cleanup_post_borrowck; mod const_debuginfo; mod const_goto; @@ -481,6 +482,7 @@ fn run_runtime_lowering_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) { // These next passes must be executed together &add_call_guards::CriticalCallEdges, &reveal_all::RevealAll, // has to be done before drop elaboration, since we need to drop opaque types, too. + &add_subtyping_projections::Subtyper, // calling this after reveal_all ensures that we don't deal with opaque types &elaborate_drops::ElaborateDrops, // This will remove extraneous landing pads which are no longer // necessary as well as well as forcing any call in a non-unwinding diff --git a/compiler/rustc_mir_transform/src/reveal_all.rs b/compiler/rustc_mir_transform/src/reveal_all.rs index 55f1eac6f84..1626cf3c035 100644 --- a/compiler/rustc_mir_transform/src/reveal_all.rs +++ b/compiler/rustc_mir_transform/src/reveal_all.rs @@ -46,16 +46,18 @@ impl<'tcx> MutVisitor<'tcx> for RevealAllVisitor<'tcx> { .filter(|elem| !matches!(elem, ProjectionElem::OpaqueCast(_))) .collect::<Vec<_>>(), ); + self.super_place(place, _context, _location); } #[inline] - fn visit_constant(&mut self, constant: &mut ConstOperand<'tcx>, _: Location) { + fn visit_constant(&mut self, constant: &mut ConstOperand<'tcx>, location: Location) { // We have to use `try_normalize_erasing_regions` here, since it's // possible that we visit impossible-to-satisfy where clauses here, // see #91745 if let Ok(c) = self.tcx.try_normalize_erasing_regions(self.param_env, constant.const_) { constant.const_ = c; } + self.super_constant(constant, location); } #[inline] |