bjoernager/rust
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Elaborate all box dereferences in ElaborateBoxDerefs

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so that it is the only pass responsible for elaboration, instead of
splitting this responsibility between the `StateTransform` and
`ElaborateBoxDerefs`.
This commit is contained in:
Tomasz Miąsko 2022-08-01 00:00:00 +00:00
parent 31d892a942
commit 4462b4af52
2 changed files with 9 additions and 102 deletions
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23
compiler/rustc_mir_transform/src/elaborate_box_derefs.rs
View file

@ -107,27 +107,8 @@ impl<'tcx> MirPass<'tcx> for ElaborateBoxDerefs {
let mut visitor =
ElaborateBoxDerefVisitor { tcx, unique_did, nonnull_did, local_decls, patch };
for (block, BasicBlockData { statements, terminator, .. }) in
body.basic_blocks.as_mut_preserves_cfg().iter_enumerated_mut()
{
let mut index = 0;
for statement in statements {
let location = Location { block, statement_index: index };
visitor.visit_statement(statement, location);
index += 1;
}
let location = Location { block, statement_index: index };
match terminator {
// yielding into a box is handled when lowering generators
Some(Terminator { kind: TerminatorKind::Yield { value, .. }, .. }) => {
visitor.visit_operand(value, location);
}
Some(terminator) => {
visitor.visit_terminator(terminator, location);
}
None => {}
}
for (block, data) in body.basic_blocks.as_mut_preserves_cfg().iter_enumerated_mut() {
visitor.visit_basic_block_data(block, data);
}
visitor.patch.apply(body);

88
compiler/rustc_mir_transform/src/generator.rs
View file

@ -1182,8 +1182,6 @@ fn create_cases<'tcx>(
transform: &TransformVisitor<'tcx>,
operation: Operation,
) -> Vec<(usize, BasicBlock)> {
let tcx = transform.tcx;
let source_info = SourceInfo::outermost(body.span);
transform
@ -1216,85 +1214,13 @@ fn create_cases<'tcx>(
if operation == Operation::Resume {
// Move the resume argument to the destination place of the `Yield` terminator
let resume_arg = Local::new(2); // 0 = return, 1 = self
// handle `box yield` properly
let box_place = if let [projection @ .., ProjectionElem::Deref] =
&**point.resume_arg.projection
{
let box_place =
Place::from(point.resume_arg.local).project_deeper(projection, tcx);
let box_ty = box_place.ty(&body.local_decls, tcx).ty;
if box_ty.is_box() { Some((box_place, box_ty)) } else { None }
} else {
None
};
if let Some((box_place, box_ty)) = box_place {
let unique_did = box_ty
.ty_adt_def()
.expect("expected Box to be an Adt")
.non_enum_variant()
.fields[0]
.did;
let Some(nonnull_def) = tcx.type_of(unique_did).ty_adt_def() else {
span_bug!(tcx.def_span(unique_did), "expected Box to contain Unique")
};
let nonnull_did = nonnull_def.non_enum_variant().fields[0].did;
let (unique_ty, nonnull_ty, ptr_ty) =
crate::elaborate_box_derefs::build_ptr_tys(
tcx,
box_ty.boxed_ty(),
unique_did,
nonnull_did,
);
let ptr_local = body.local_decls.push(LocalDecl::new(ptr_ty, body.span));
statements.push(Statement {
source_info,
kind: StatementKind::StorageLive(ptr_local),
});
statements.push(Statement {
source_info,
kind: StatementKind::Assign(Box::new((
Place::from(ptr_local),
Rvalue::Use(Operand::Copy(box_place.project_deeper(
&crate::elaborate_box_derefs::build_projection(
unique_ty, nonnull_ty, ptr_ty,
),
tcx,
))),
))),
});
statements.push(Statement {
source_info,
kind: StatementKind::Assign(Box::new((
Place::from(ptr_local)
.project_deeper(&[ProjectionElem::Deref], tcx),
Rvalue::Use(Operand::Move(resume_arg.into())),
))),
});
statements.push(Statement {
source_info,
kind: StatementKind::StorageDead(ptr_local),
});
} else {
statements.push(Statement {
source_info,
kind: StatementKind::Assign(Box::new((
point.resume_arg,
Rvalue::Use(Operand::Move(resume_arg.into())),
))),
});
}
statements.push(Statement {
source_info,
kind: StatementKind::Assign(Box::new((
point.resume_arg,
Rvalue::Use(Operand::Move(resume_arg.into())),
))),
});
}
// Then jump to the real target