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Auto merge of #90050 - michaelwoerister:fix-vtable-debug-name-crash-90019, r=wesleywiser

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Erase late-bound regions before computing vtable debuginfo name.

Fixes #90019.

The `msvc_enum_fallback()` for computing enum type names needs to access the memory layout of niche enums in order to determine the type name. `compute_debuginfo_vtable_name()` did not properly erase regions before computing type names which made memory layout computation ICE when encountering un-erased regions.

r? `@wesleywiser`
This commit is contained in:
bors 2021-10-20 14:37:48 +00:00
parent 6162529a01 5929cf0d67
commit 3d71e749a2
2 changed files with 14 additions and 7 deletions
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11
compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs
View file

@ -480,14 +480,11 @@ pub fn compute_debuginfo_vtable_name<'tcx>(
}
if let Some(trait_ref) = trait_ref {
push_item_name(tcx, trait_ref.skip_binder().def_id, true, &mut vtable_name);
let trait_ref =
tcx.normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), trait_ref);
push_item_name(tcx, trait_ref.def_id, true, &mut vtable_name);
visited.clear();
push_generic_params_internal(
tcx,
trait_ref.skip_binder().substs,
&mut vtable_name,
&mut visited,
);
push_generic_params_internal(tcx, trait_ref.substs, &mut vtable_name, &mut visited);
} else {
vtable_name.push_str("_");
}

10
src/test/codegen/debug-vtable.rs
View file

@ -18,6 +18,9 @@
// MSVC-LABEL: !DIGlobalVariable(name: "impl$<debug_vtable::Foo, _>::vtable$"
// CHECK: !DISubrange(count: 3
// NONMSVC-LABEL: !DIGlobalVariable(name: "<debug_vtable::bar::{closure#0} as core::ops::function::FnOnce<(core::option::Option<&dyn core::ops::function::Fn<(), Output=()>>)>>::{vtable}"
// MSVC-LABEL: !DIGlobalVariable(name: "impl$<debug_vtable::bar::closure$0, core::ops::function::FnOnce<tuple$<enum$<core::option::Option<ref$<dyn$<core::ops::function::Fn<tuple$<>,assoc$<Output,tuple$<> > > > > >, {{.*}}, {{.*}}, Some> > > >::vtable$"
#![crate_type = "lib"]
pub struct Foo;
@ -45,3 +48,10 @@ pub fn foo(x: &Foo) -> (u32, (u64, i8), &dyn Send) {
let z: &dyn SomeTraitWithGenerics<u64, i8> = x;
(y.method1(), z.method1(), x as &dyn Send)
}
// Constructing the debuginfo name for the FnOnce vtable below initially caused an ICE on MSVC
// because the trait type contains a late bound region that needed to be erased before the type
// layout for the niche enum `Option<&dyn Fn()>` could be computed.
pub fn bar() -> Box<dyn FnOnce(Option<&dyn Fn()>)> {
Box::new(|_x: Option<&dyn Fn()>| {})
}