Refactor to make interpreter and codegen backend neutral to vtable internal representation.
This commit is contained in:
Charles Lew
parent
14831568d5
commit
a86d3a7e45
10 changed files with 246 additions and 177 deletions
|
|
@ -31,7 +31,8 @@ use rustc_hir::def_id::DefId;
|
|||
use rustc_middle::ty::fold::TypeFoldable;
|
||||
use rustc_middle::ty::subst::{InternalSubsts, SubstsRef};
|
||||
use rustc_middle::ty::{
|
||||
self, GenericParamDefKind, ParamEnv, ToPredicate, Ty, TyCtxt, WithConstness,
|
||||
self, GenericParamDefKind, ParamEnv, ToPredicate, Ty, TyCtxt, VtblEntry, WithConstness,
|
||||
COMMON_VTABLE_ENTRIES,
|
||||
};
|
||||
use rustc_span::Span;
|
||||
|
||||
|
|
@ -455,59 +456,89 @@ fn subst_and_check_impossible_predicates<'tcx>(
|
|||
|
||||
/// Given a trait `trait_ref`, iterates the vtable entries
|
||||
/// that come from `trait_ref`, including its supertraits.
|
||||
fn vtable_methods<'tcx>(
|
||||
fn vtable_entries<'tcx>(
|
||||
tcx: TyCtxt<'tcx>,
|
||||
trait_ref: ty::PolyTraitRef<'tcx>,
|
||||
) -> &'tcx [Option<(DefId, SubstsRef<'tcx>)>] {
|
||||
debug!("vtable_methods({:?})", trait_ref);
|
||||
) -> &'tcx [VtblEntry<'tcx>] {
|
||||
debug!("vtable_entries({:?})", trait_ref);
|
||||
|
||||
tcx.arena.alloc_from_iter(supertraits(tcx, trait_ref).flat_map(move |trait_ref| {
|
||||
let trait_methods = tcx
|
||||
.associated_items(trait_ref.def_id())
|
||||
.in_definition_order()
|
||||
.filter(|item| item.kind == ty::AssocKind::Fn);
|
||||
let entries = COMMON_VTABLE_ENTRIES.iter().cloned().chain(
|
||||
supertraits(tcx, trait_ref).flat_map(move |trait_ref| {
|
||||
let trait_methods = tcx
|
||||
.associated_items(trait_ref.def_id())
|
||||
.in_definition_order()
|
||||
.filter(|item| item.kind == ty::AssocKind::Fn);
|
||||
|
||||
// Now list each method's DefId and InternalSubsts (for within its trait).
|
||||
// If the method can never be called from this object, produce None.
|
||||
trait_methods.map(move |trait_method| {
|
||||
debug!("vtable_methods: trait_method={:?}", trait_method);
|
||||
let def_id = trait_method.def_id;
|
||||
// Now list each method's DefId and InternalSubsts (for within its trait).
|
||||
// If the method can never be called from this object, produce `Vacant`.
|
||||
trait_methods.map(move |trait_method| {
|
||||
debug!("vtable_entries: trait_method={:?}", trait_method);
|
||||
let def_id = trait_method.def_id;
|
||||
|
||||
// Some methods cannot be called on an object; skip those.
|
||||
if !is_vtable_safe_method(tcx, trait_ref.def_id(), &trait_method) {
|
||||
debug!("vtable_methods: not vtable safe");
|
||||
return None;
|
||||
}
|
||||
// Some methods cannot be called on an object; skip those.
|
||||
if !is_vtable_safe_method(tcx, trait_ref.def_id(), &trait_method) {
|
||||
debug!("vtable_entries: not vtable safe");
|
||||
return VtblEntry::Vacant;
|
||||
}
|
||||
|
||||
// The method may have some early-bound lifetimes; add regions for those.
|
||||
let substs = trait_ref.map_bound(|trait_ref| {
|
||||
InternalSubsts::for_item(tcx, def_id, |param, _| match param.kind {
|
||||
GenericParamDefKind::Lifetime => tcx.lifetimes.re_erased.into(),
|
||||
GenericParamDefKind::Type { .. } | GenericParamDefKind::Const { .. } => {
|
||||
trait_ref.substs[param.index as usize]
|
||||
}
|
||||
})
|
||||
});
|
||||
// The method may have some early-bound lifetimes; add regions for those.
|
||||
let substs = trait_ref.map_bound(|trait_ref| {
|
||||
InternalSubsts::for_item(tcx, def_id, |param, _| match param.kind {
|
||||
GenericParamDefKind::Lifetime => tcx.lifetimes.re_erased.into(),
|
||||
GenericParamDefKind::Type { .. } | GenericParamDefKind::Const { .. } => {
|
||||
trait_ref.substs[param.index as usize]
|
||||
}
|
||||
})
|
||||
});
|
||||
|
||||
// The trait type may have higher-ranked lifetimes in it;
|
||||
// erase them if they appear, so that we get the type
|
||||
// at some particular call site.
|
||||
let substs =
|
||||
tcx.normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), substs);
|
||||
// The trait type may have higher-ranked lifetimes in it;
|
||||
// erase them if they appear, so that we get the type
|
||||
// at some particular call site.
|
||||
let substs =
|
||||
tcx.normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), substs);
|
||||
|
||||
// It's possible that the method relies on where-clauses that
|
||||
// do not hold for this particular set of type parameters.
|
||||
// Note that this method could then never be called, so we
|
||||
// do not want to try and codegen it, in that case (see #23435).
|
||||
let predicates = tcx.predicates_of(def_id).instantiate_own(tcx, substs);
|
||||
if impossible_predicates(tcx, predicates.predicates) {
|
||||
debug!("vtable_methods: predicates do not hold");
|
||||
return None;
|
||||
}
|
||||
// It's possible that the method relies on where-clauses that
|
||||
// do not hold for this particular set of type parameters.
|
||||
// Note that this method could then never be called, so we
|
||||
// do not want to try and codegen it, in that case (see #23435).
|
||||
let predicates = tcx.predicates_of(def_id).instantiate_own(tcx, substs);
|
||||
if impossible_predicates(tcx, predicates.predicates) {
|
||||
debug!("vtable_entries: predicates do not hold");
|
||||
return VtblEntry::Vacant;
|
||||
}
|
||||
|
||||
Some((def_id, substs))
|
||||
})
|
||||
}))
|
||||
VtblEntry::Method(def_id, substs)
|
||||
})
|
||||
}),
|
||||
);
|
||||
|
||||
tcx.arena.alloc_from_iter(entries)
|
||||
}
|
||||
|
||||
/// Find slot base for trait methods within vtable entries of another trait
|
||||
fn vtable_trait_first_method_offset<'tcx>(
|
||||
tcx: TyCtxt<'tcx>,
|
||||
key: (
|
||||
ty::PolyTraitRef<'tcx>, // trait_to_be_found
|
||||
ty::PolyTraitRef<'tcx>, // trait_owning_vtable
|
||||
),
|
||||
) -> usize {
|
||||
let (trait_to_be_found, trait_owning_vtable) = key;
|
||||
|
||||
let mut supertraits = util::supertraits(tcx, trait_owning_vtable);
|
||||
|
||||
// For each of the non-matching predicates that
|
||||
// we pass over, we sum up the set of number of vtable
|
||||
// entries, so that we can compute the offset for the selected
|
||||
// trait.
|
||||
let vtable_base = ty::COMMON_VTABLE_ENTRIES.len()
|
||||
+ supertraits
|
||||
.by_ref()
|
||||
.take_while(|t| *t != trait_to_be_found)
|
||||
.map(|t| util::count_own_vtable_entries(tcx, t))
|
||||
.sum::<usize>();
|
||||
|
||||
vtable_base
|
||||
}
|
||||
|
||||
/// Check whether a `ty` implements given trait(trait_def_id).
|
||||
|
|
@ -547,7 +578,7 @@ pub fn provide(providers: &mut ty::query::Providers) {
|
|||
specialization_graph_of: specialize::specialization_graph_provider,
|
||||
specializes: specialize::specializes,
|
||||
codegen_fulfill_obligation: codegen::codegen_fulfill_obligation,
|
||||
vtable_methods,
|
||||
vtable_entries,
|
||||
type_implements_trait,
|
||||
subst_and_check_impossible_predicates,
|
||||
mir_abstract_const: |tcx, def_id| {
|
||||
|
|
|
|||
|
|
@ -396,19 +396,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
|
|||
let mut nested = vec![];
|
||||
|
||||
let mut supertraits = util::supertraits(tcx, ty::Binder::dummy(object_trait_ref));
|
||||
|
||||
// For each of the non-matching predicates that
|
||||
// we pass over, we sum up the set of number of vtable
|
||||
// entries, so that we can compute the offset for the selected
|
||||
// trait.
|
||||
let vtable_base = supertraits
|
||||
.by_ref()
|
||||
.take(index)
|
||||
.map(|t| super::util::count_own_vtable_entries(tcx, t))
|
||||
.sum();
|
||||
|
||||
let unnormalized_upcast_trait_ref =
|
||||
supertraits.next().expect("supertraits iterator no longer has as many elements");
|
||||
supertraits.nth(index).expect("supertraits iterator no longer has as many elements");
|
||||
|
||||
let upcast_trait_ref = normalize_with_depth_to(
|
||||
self,
|
||||
|
|
@ -490,6 +479,12 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
|
|||
}
|
||||
|
||||
debug!(?nested, "object nested obligations");
|
||||
|
||||
let vtable_base = super::super::vtable_trait_first_method_offset(
|
||||
tcx,
|
||||
(unnormalized_upcast_trait_ref, ty::Binder::dummy(object_trait_ref)),
|
||||
);
|
||||
|
||||
Ok(ImplSourceObjectData { upcast_trait_ref, vtable_base, nested })
|
||||
}
|
||||
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue