bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

Auto merge of #123106 - maurer:cfi-closures, r=compiler-errors

Browse source 
CFI: Abstract Closures and Coroutines

This will abstract coroutines in a moment, it's just abstracting closures for now to show `@rcvalle`

This uses the same principal as the methods on traits - figure out the `dyn` type representing the fn trait, instantiate it, and attach that alias set. We're essentially just computing how we would be called in a dynamic context, and attaching that.
This commit is contained in:
bors 2024-03-30 17:56:26 +00:00
commit 70714e38f2
5 changed files with 241 additions and 59 deletions
Download patch file Download diff file Expand all files Collapse all files

131
compiler/rustc_symbol_mangling/src/typeid/typeid_itanium_cxx_abi.rs
View file

@ -10,6 +10,7 @@
use rustc_data_structures::base_n;
use rustc_data_structures::fx::FxHashMap;
use rustc_hir as hir;
use rustc_hir::lang_items::LangItem;
use rustc_middle::ty::layout::IntegerExt;
use rustc_middle::ty::TypeVisitableExt;
use rustc_middle::ty::{
@ -641,9 +642,7 @@ fn encode_ty<'tcx>(
}
// Function types
ty::FnDef(def_id, args)
| ty::Closure(def_id, args)
| ty::CoroutineClosure(def_id, args) => {
ty::FnDef(def_id, args) | ty::Closure(def_id, args) => {
// u<length><name>[I<element-type1..element-typeN>E], where <element-type> is <subst>,
// as vendor extended type.
let mut s = String::new();
@ -654,6 +653,18 @@ fn encode_ty<'tcx>(
typeid.push_str(&s);
}
ty::CoroutineClosure(def_id, args) => {
// u<length><name>[I<element-type1..element-typeN>E], where <element-type> is <subst>,
// as vendor extended type.
let mut s = String::new();
let name = encode_ty_name(tcx, *def_id);
let _ = write!(s, "u{}{}", name.len(), &name);
let parent_args = tcx.mk_args(args.as_coroutine_closure().parent_args());
s.push_str(&encode_args(tcx, parent_args, dict, options));
compress(dict, DictKey::Ty(ty, TyQ::None), &mut s);
typeid.push_str(&s);
}
ty::Coroutine(def_id, args, ..) => {
// u<length><name>[I<element-type1..element-typeN>E], where <element-type> is <subst>,
// as vendor extended type.
@ -1151,43 +1162,91 @@ pub fn typeid_for_instance<'tcx>(
};
let stripped_ty = strip_receiver_auto(tcx, upcast_ty);
instance.args = tcx.mk_args_trait(stripped_ty, instance.args.into_iter().skip(1));
} else if let ty::InstanceDef::VTableShim(def_id) = instance.def
&& let Some(trait_id) = tcx.trait_of_item(def_id)
{
// VTableShims may have a trait method, but a concrete Self. This is not suitable for a vtable,
// as the caller will not know the concrete Self.
let trait_ref = ty::TraitRef::new(tcx, trait_id, instance.args);
let invoke_ty = trait_object_ty(tcx, ty::Binder::dummy(trait_ref));
instance.args = tcx.mk_args_trait(invoke_ty, trait_ref.args.into_iter().skip(1));
}
if !options.contains(EncodeTyOptions::NO_SELF_TYPE_ERASURE)
&& let Some(impl_id) = tcx.impl_of_method(instance.def_id())
&& let Some(trait_ref) = tcx.impl_trait_ref(impl_id)
{
let impl_method = tcx.associated_item(instance.def_id());
let method_id = impl_method
.trait_item_def_id
.expect("Part of a trait implementation, but not linked to the def_id?");
let trait_method = tcx.associated_item(method_id);
let trait_id = trait_ref.skip_binder().def_id;
if traits::is_vtable_safe_method(tcx, trait_id, trait_method)
&& tcx.object_safety_violations(trait_id).is_empty()
if !options.contains(EncodeTyOptions::NO_SELF_TYPE_ERASURE) {
if let Some(impl_id) = tcx.impl_of_method(instance.def_id())
&& let Some(trait_ref) = tcx.impl_trait_ref(impl_id)
{
// Trait methods will have a Self polymorphic parameter, where the concreteized
// implementatation will not. We need to walk back to the more general trait method
let trait_ref = tcx.instantiate_and_normalize_erasing_regions(
instance.args,
ty::ParamEnv::reveal_all(),
trait_ref,
);
let invoke_ty = trait_object_ty(tcx, ty::Binder::dummy(trait_ref));
let impl_method = tcx.associated_item(instance.def_id());
let method_id = impl_method
.trait_item_def_id
.expect("Part of a trait implementation, but not linked to the def_id?");
let trait_method = tcx.associated_item(method_id);
let trait_id = trait_ref.skip_binder().def_id;
if traits::is_vtable_safe_method(tcx, trait_id, trait_method)
&& tcx.object_safety_violations(trait_id).is_empty()
{
// Trait methods will have a Self polymorphic parameter, where the concreteized
// implementatation will not. We need to walk back to the more general trait method
let trait_ref = tcx.instantiate_and_normalize_erasing_regions(
instance.args,
ty::ParamEnv::reveal_all(),
trait_ref,
);
let invoke_ty = trait_object_ty(tcx, ty::Binder::dummy(trait_ref));
// At the call site, any call to this concrete function through a vtable will be
// `Virtual(method_id, idx)` with appropriate arguments for the method. Since we have the
// original method id, and we've recovered the trait arguments, we can make the callee
// instance we're computing the alias set for match the caller instance.
//
// Right now, our code ignores the vtable index everywhere, so we use 0 as a placeholder.
// If we ever *do* start encoding the vtable index, we will need to generate an alias set
// based on which vtables we are putting this method into, as there will be more than one
// index value when supertraits are involved.
instance.def = ty::InstanceDef::Virtual(method_id, 0);
let abstract_trait_args =
tcx.mk_args_trait(invoke_ty, trait_ref.args.into_iter().skip(1));
instance.args = instance.args.rebase_onto(tcx, impl_id, abstract_trait_args);
// At the call site, any call to this concrete function through a vtable will be
// `Virtual(method_id, idx)` with appropriate arguments for the method. Since we have the
// original method id, and we've recovered the trait arguments, we can make the callee
// instance we're computing the alias set for match the caller instance.
//
// Right now, our code ignores the vtable index everywhere, so we use 0 as a placeholder.
// If we ever *do* start encoding the vtable index, we will need to generate an alias set
// based on which vtables we are putting this method into, as there will be more than one
// index value when supertraits are involved.
instance.def = ty::InstanceDef::Virtual(method_id, 0);
let abstract_trait_args =
tcx.mk_args_trait(invoke_ty, trait_ref.args.into_iter().skip(1));
instance.args = instance.args.rebase_onto(tcx, impl_id, abstract_trait_args);
}
} else if tcx.is_closure_like(instance.def_id()) {
// We're either a closure or a coroutine. Our goal is to find the trait we're defined on,
// instantiate it, and take the type of its only method as our own.
let closure_ty = instance.ty(tcx, ty::ParamEnv::reveal_all());
let (trait_id, inputs) = match closure_ty.kind() {
ty::Closure(..) => {
let closure_args = instance.args.as_closure();
let trait_id = tcx.fn_trait_kind_to_def_id(closure_args.kind()).unwrap();
let tuple_args =
tcx.instantiate_bound_regions_with_erased(closure_args.sig()).inputs()[0];
(trait_id, tuple_args)
}
ty::Coroutine(..) => (
tcx.require_lang_item(LangItem::Coroutine, None),
instance.args.as_coroutine().resume_ty(),
),
ty::CoroutineClosure(..) => (
tcx.require_lang_item(LangItem::FnOnce, None),
tcx.instantiate_bound_regions_with_erased(
instance.args.as_coroutine_closure().coroutine_closure_sig(),
)
.tupled_inputs_ty,
),
x => bug!("Unexpected type kind for closure-like: {x:?}"),
};
let trait_ref = ty::TraitRef::new(tcx, trait_id, [closure_ty, inputs]);
let invoke_ty = trait_object_ty(tcx, ty::Binder::dummy(trait_ref));
let abstract_args = tcx.mk_args_trait(invoke_ty, trait_ref.args.into_iter().skip(1));
// There should be exactly one method on this trait, and it should be the one we're
// defining.
let call = tcx
.associated_items(trait_id)
.in_definition_order()
.find(|it| it.kind == ty::AssocKind::Fn)
.expect("No call-family function on closure-like Fn trait?")
.def_id;
instance.def = ty::InstanceDef::Virtual(call, 0);
instance.args = abstract_args;
}
}