From 0574167d92a232cb8f5a9107aabda0aefbc39e8b Mon Sep 17 00:00:00 2001
From: Antoine Pitrou <antoine@python.org>
Date: Tue, 19 Jul 2022 16:40:28 +0200
Subject: [PATCH] Fix #9947: make the ABI identical between debug and non-debug
 builds

---
 src/google/protobuf/message_lite.cc |  8 ++------
 src/google/protobuf/metadata_lite.h | 13 ++++++++++---
 2 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/src/google/protobuf/message_lite.cc b/src/google/protobuf/message_lite.cc
index 27a8b38bab56..2674b2698e1f 100644
--- a/src/google/protobuf/message_lite.cc
+++ b/src/google/protobuf/message_lite.cc
@@ -521,18 +521,14 @@ void GenericTypeHandler<std::string>::Merge(const std::string& from,
   *to = from;
 }
 
-// Non-inline implementations of InternalMetadata routines
-#if defined(NDEBUG) || defined(_MSC_VER)
-// for opt and MSVC builds, the destructor is defined in the header.
-#else
+// Non-inline implementations of InternalMetadata destructor
 // This is moved out of the header because the GOOGLE_DCHECK produces a lot of code.
-InternalMetadata::~InternalMetadata() {
+void InternalMetadata::CheckedDestruct() {
   if (HasMessageOwnedArenaTag()) {
     GOOGLE_DCHECK(!HasUnknownFieldsTag());
     delete reinterpret_cast<Arena*>(ptr_ - kMessageOwnedArenaTagMask);
   }
 }
-#endif
 
 // Non-inline variants of std::string specializations for
 // various InternalMetadata routines.
diff --git a/src/google/protobuf/metadata_lite.h b/src/google/protobuf/metadata_lite.h
index af840e5065c9..d015dc2f9da4 100644
--- a/src/google/protobuf/metadata_lite.h
+++ b/src/google/protobuf/metadata_lite.h
@@ -77,15 +77,19 @@ class PROTOBUF_EXPORT InternalMetadata {
     GOOGLE_DCHECK(!is_message_owned || arena != nullptr);
   }
 
-#if defined(NDEBUG) || defined(_MSC_VER)
+  // To keep the ABI identical between debug and non-debug builds,
+  // the destructor is always defined here even though it may delegate
+  // to a non-inline private method.
+  // (see https://github.com/protocolbuffers/protobuf/issues/9947)
   ~InternalMetadata() {
+#if defined(NDEBUG) || defined(_MSC_VER)
     if (HasMessageOwnedArenaTag()) {
       delete reinterpret_cast<Arena*>(ptr_ - kMessageOwnedArenaTagMask);
     }
-  }
 #else
-  ~InternalMetadata();
+    CheckedDestruct();
 #endif
+  }
 
   template <typename T>
   void Delete() {
@@ -264,6 +268,9 @@ class PROTOBUF_EXPORT InternalMetadata {
   PROTOBUF_NOINLINE void DoSwap(T* other) {
     mutable_unknown_fields<T>()->Swap(other);
   }
+
+  // Private helper with debug checks for ~InternalMetadata()
+  void CheckedDestruct();
 };
 
 // String Template specializations.