Auto merge of #58315 - gnzlbg:returns_twice, r=alexcrichton

Implement unstable ffi_return_twice attribute

This PR implements [RFC2633](https://github.com/rust-lang/rfcs/pull/2633)

r? @eddyb

1 files changed, 2 insertions, 0 deletions

diff --git a/src/rustllvm/RustWrapper.cpp b/src/rustllvm/RustWrapper.cpp
index b33165b8463..a00417a3629 100644
--- a/src/rustllvm/RustWrapper.cpp
+++ b/src/rustllvm/RustWrapper.cpp
@@ -190,6 +190,8 @@ static Attribute::AttrKind fromRust(LLVMRustAttribute Kind) {
     return Attribute::NonLazyBind;
   case OptimizeNone:
     return Attribute::OptimizeNone;
+  case ReturnsTwice:
+    return Attribute::ReturnsTwice;
   }
   report_fatal_error("bad AttributeKind");
 }