bjoernager/rust
bjoernager/rust
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Implement pointer casting.

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This commit is contained in:
Charles Lew 2021-07-31 22:46:23 +08:00
parent 7069a8c2b7
commit 63ed625313
11 changed files with 256 additions and 88 deletions
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16
compiler/rustc_trait_selection/src/traits/mod.rs
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@ -756,16 +756,17 @@ fn vtable_trait_first_method_offset<'tcx>(
}
/// Find slot offset for trait vptr within vtable entries of another trait
/// FIXME: This function is not yet used. Remove `#[allow(dead_code)]` when it's used in upcoming pr.
#[allow(dead_code)]
fn vtable_trait_vptr_slot_offset<'tcx>(
pub fn vtable_trait_upcasting_coercion_new_vptr_slot(
tcx: TyCtxt<'tcx>,
key: (
ty::PolyTraitRef<'tcx>, // trait_to_be_found
ty::PolyTraitRef<'tcx>, // trait_owning_vtable
ty::PolyTraitRef<'tcx>, // trait owning vtable
ty::PolyTraitRef<'tcx>, // super trait ref
),
) -> Option<usize> {
let (trait_to_be_found, trait_owning_vtable) = key;
let (trait_owning_vtable, super_trait_ref) = key;
let super_trait_did = super_trait_ref.def_id();
// FIXME: take substsref part into account here after upcasting coercion allows the same def_id occur
// multiple times.
let vtable_segment_callback = {
let mut vptr_offset = 0;
@ -776,7 +777,7 @@ fn vtable_trait_vptr_slot_offset<'tcx>(
}
VtblSegment::TraitOwnEntries { trait_ref, emit_vptr } => {
vptr_offset += util::count_own_vtable_entries(tcx, trait_ref);
if trait_ref == trait_to_be_found {
if trait_ref.def_id() == super_trait_did {
if emit_vptr {
return ControlFlow::Break(Some(vptr_offset));
} else {
@ -810,6 +811,7 @@ pub fn provide(providers: &mut ty::query::Providers) {
specializes: specialize::specializes,
codegen_fulfill_obligation: codegen::codegen_fulfill_obligation,
vtable_entries,
vtable_trait_upcasting_coercion_new_vptr_slot,
subst_and_check_impossible_predicates,
mir_abstract_const: |tcx, def_id| {
let def_id = def_id.expect_local();