From 382b2fc89e664ea8103ba81cb71fb0e7dca54b50 Mon Sep 17 00:00:00 2001
From: Mykola Pokhylets <mykola.pokhylets@gmail.com>
Date: Wed, 1 Oct 2025 17:01:25 +0200
Subject: [PATCH] Fix swift_bridgeObjectRetain() dropping integer bits

In particular this was breaking deferred type-checking of arrays.

Regression was introduced in https://github.com/swiftlang/swift/commit/724a9a7da404a0635fb9717a3f0f578dbbe0eb28
---
 stdlib/public/runtime/SwiftObject.mm | 30 ++++------------------------
 1 file changed, 4 insertions(+), 26 deletions(-)

diff --git a/stdlib/public/runtime/SwiftObject.mm b/stdlib/public/runtime/SwiftObject.mm
index 97d28325ed162..78aa562de0f51 100644
--- a/stdlib/public/runtime/SwiftObject.mm
+++ b/stdlib/public/runtime/SwiftObject.mm
@@ -677,20 +677,6 @@ static bool isBridgeObjectTaggedPointer(void *object) {
   return (void*)(uintptr_t(object) & ~unTaggedNonNativeBridgeObjectBits);
 }
 
-#if SWIFT_OBJC_INTEROP
-#if __arm64__
-// Marking this as noinline allows swift_bridgeObjectRetain to avoid emitting
-// a stack frame for the swift_retain path on ARM64. It makes for worse codegen
-// on x86-64, though, so limit it to ARM64.
-SWIFT_NOINLINE
-#endif
-static void *objcRetainAndReturn(void *object) {
-  auto const objectRef = toPlainObject_unTagged_bridgeObject(object);
-  objc_retain(static_cast<id>(objectRef));
-  return object;
-}
-#endif
-
 void *swift::swift_bridgeObjectRetain(void *object) {
 #if SWIFT_OBJC_INTEROP
   if (isObjCTaggedPointer(object) || isBridgeObjectTaggedPointer(object))
@@ -698,22 +684,14 @@ static bool isBridgeObjectTaggedPointer(void *object) {
 #endif
 
   auto const objectRef = toPlainObject_unTagged_bridgeObject(object);
-
 #if SWIFT_OBJC_INTEROP
   if (!isNonNative_unTagged_bridgeObject(object)) {
-    return swift_retain(static_cast<HeapObject *>(objectRef));
+    swift_retain(static_cast<HeapObject *>(objectRef));
+    return object;
   }
-
-  // Put the call to objc_retain in a separate function, tail-called here. This
-  // allows the fast path of swift_bridgeObjectRetain to avoid creating a stack
-  // frame on ARM64. We can't directly tail-call objc_retain, because
-  // swift_bridgeObjectRetain returns the pointer with objectPointerIsObjCBit
-  // set, so we have to make a non-tail call and then return the value with the
-  // bit set.
-  SWIFT_MUSTTAIL return objcRetainAndReturn(object);
+  objc_retain(static_cast<id>(objectRef));
+  return object;
 #else
-  // No tail call here. When !SWIFT_OBJC_INTEROP, the value of objectRef may be
-  // different from that of object, e.g. on Linux ARM64.
   swift_retain(static_cast<HeapObject *>(objectRef));
   return object;
 #endif