Native: support reentrant mode for CalledFromNativeGuard

kotlin-native/runtime/src/legacymm/cpp/Memory.cpp

@@ -3746,7 +3746,7 @@ kotlin::ThreadState kotlin::GetThreadState(MemoryState* thread) noexcept {
     return ThreadState::kRunnable;
 }
 
-ALWAYS_INLINE kotlin::CalledFromNativeGuard::CalledFromNativeGuard() noexcept {
+ALWAYS_INLINE kotlin::CalledFromNativeGuard::CalledFromNativeGuard(bool reentrant) noexcept {
     // no-op, used by the new MM only.
 }
 

kotlin-native/runtime/src/main/cpp/Memory.h

@@ -447,13 +447,15 @@ private:
 // No-op for old GC.
 class CalledFromNativeGuard final : private Pinned {
 public:
-    ALWAYS_INLINE CalledFromNativeGuard() noexcept;
+    ALWAYS_INLINE CalledFromNativeGuard(bool reentrant = false) noexcept;
 
     ~CalledFromNativeGuard() noexcept {
-        SwitchThreadState(thread_, ThreadState::kNative);
+        SwitchThreadState(thread_, oldState_, reentrant_);
     }
 private:
     MemoryState* thread_;
+    ThreadState oldState_;
+    bool reentrant_;
 };
 
 template <ThreadState state, typename R, typename... Args>

kotlin-native/runtime/src/mm/cpp/Memory.cpp

@@ -532,10 +532,10 @@ MemoryState* kotlin::mm::GetMemoryState() {
     return ToMemoryState(ThreadRegistry::Instance().CurrentThreadDataNode());
 }
 
-ALWAYS_INLINE kotlin::CalledFromNativeGuard::CalledFromNativeGuard() noexcept {
+ALWAYS_INLINE kotlin::CalledFromNativeGuard::CalledFromNativeGuard(bool reentrant) noexcept : reentrant_(reentrant) {
     Kotlin_initRuntimeIfNeeded();
     thread_ = mm::GetMemoryState();
-    SwitchThreadState(thread_, ThreadState::kRunnable);
+    oldState_ = SwitchThreadState(thread_, ThreadState::kRunnable, reentrant_);
 }
 
 const bool kotlin::kSupportsMultipleMutators = kotlin::gc::kSupportsMultipleMutators;