From ae48c4ce2cc5d3dafe5f2f0733a92fd871907f65 Mon Sep 17 00:00:00 2001
From: Ramon de C Valle <rcvalle@users.noreply.github.com>
Date: Thu, 21 Mar 2024 13:29:24 -0700
Subject: [PATCH] CFI: Fix encode_ty: unexpected 'CoroutineWitness'

Fix #122705 by adding support for encoding `ty:CoroutineClosure`.
---
 .../src/typeid/typeid_itanium_cxx_abi.rs          |  8 +++++++-
 .../sanitizer/cfi-async-closure-issue-122705.rs   | 15 +++++++++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)
 create mode 100644 tests/ui/sanitizer/cfi-async-closure-issue-122705.rs

diff --git a/compiler/rustc_symbol_mangling/src/typeid/typeid_itanium_cxx_abi.rs b/compiler/rustc_symbol_mangling/src/typeid/typeid_itanium_cxx_abi.rs
index 06a07678dc621..e6423c0caa45b 100644
--- a/compiler/rustc_symbol_mangling/src/typeid/typeid_itanium_cxx_abi.rs
+++ b/compiler/rustc_symbol_mangling/src/typeid/typeid_itanium_cxx_abi.rs
@@ -1278,6 +1278,13 @@ fn transform_ty<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>, options: TransformTyOptio
             );
         }
 
+        ty::CoroutineClosure(_, args) => {
+            // Transform async closures into function pointers
+            let fn_ptr = args.as_coroutine_closure().signature_parts_ty();
+            // Transform fn_sig inputs and output
+            ty = transform_ty(tcx, fn_ptr, options);
+        }
+
         ty::Ref(region, ty0, ..) => {
             // Remove references from function items, closures, and Fn trait objects
             if ty0.is_fn_def() || ty0.is_closure() || is_dynamic_fn_trait(tcx, *ty0) {
@@ -1364,7 +1371,6 @@ fn transform_ty<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>, options: TransformTyOptio
 
         ty::Bound(..)
         | ty::Error(..)
-        | ty::CoroutineClosure(..)
         | ty::CoroutineWitness(..)
         | ty::Infer(..)
         | ty::Placeholder(..) => {
diff --git a/tests/ui/sanitizer/cfi-async-closure-issue-122705.rs b/tests/ui/sanitizer/cfi-async-closure-issue-122705.rs
new file mode 100644
index 0000000000000..2f86d2e9fe61c
--- /dev/null
+++ b/tests/ui/sanitizer/cfi-async-closure-issue-122705.rs
@@ -0,0 +1,15 @@
+// Verifies that using async closure works.
+//
+//@ needs-sanitizer-cfi
+//@ compile-flags: -Clto -Cprefer-dynamic=off -Ctarget-feature=-crt-static -Zsanitizer=cfi -Copt-level=0 --edition=2021
+//@ run-pass
+
+#![feature(async_closure)]
+
+#[inline(never)]
+fn foo<T>(_: T) {}
+
+fn main() {
+    let a = async move |_: i32, _: i32| {};
+    foo(a);
+}