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Properly handle Pin<&mut dyn* Trait> receiver in codegen

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This commit is contained in:
Michael Goulet 2022-11-19 03:06:21 +00:00
parent c620a972f3
commit 8f79fc24e3
3 changed files with 86 additions and 6 deletions
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30
compiler/rustc_codegen_ssa/src/mir/block.rs
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@ -938,7 +938,9 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
// that is understood elsewhere in the compiler as a method on
// `dyn Trait`.
// To get a `*mut RcBox<Self>`, we just keep unwrapping newtypes until
// we get a value of a built-in pointer type
// we get a value of a built-in pointer type.
//
// This is also relevant for `Pin<&mut Self>`, where we need to peel the `Pin`.
'descend_newtypes: while !op.layout.ty.is_unsafe_ptr()
&& !op.layout.ty.is_region_ptr()
{
@ -980,13 +982,29 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
continue;
}
Immediate(_) => {
let ty::Ref(_, ty, _) = op.layout.ty.kind() else {
span_bug!(span, "can't codegen a virtual call on {:#?}", op);
};
if !ty.is_dyn_star() {
// See comment above explaining why we peel these newtypes
'descend_newtypes: while !op.layout.ty.is_unsafe_ptr()
&& !op.layout.ty.is_region_ptr()
{
for i in 0..op.layout.fields.count() {
let field = op.extract_field(bx, i);
if !field.layout.is_zst() {
// we found the one non-zero-sized field that is allowed
// now find *its* non-zero-sized field, or stop if it's a
// pointer
op = field;
continue 'descend_newtypes;
}
}
span_bug!(span, "receiver has no non-zero-sized fields {:?}", op);
}
// Make sure that we've actually unwrapped the rcvr down
// to a pointer or ref to `dyn* Trait`.
if !op.layout.ty.builtin_deref(true).unwrap().ty.is_dyn_star() {
span_bug!(span, "can't codegen a virtual call on {:#?}", op);
}
// FIXME(dyn-star): Make sure this is done on a &dyn* receiver
let place = op.deref(bx.cx());
let data_ptr = place.project_field(bx, 0);
let meta_ptr = place.project_field(bx, 1);